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Regulation of Calvarial Osteogenesis by Concomitant De-repression of GLI3 and Activation of IHH Targets

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Lotta K. Veistinen; Tuija Mustonen; Tuija Mustonen; Md. Rakibul Hasan; Maarit Takatalo; Yukiho Kobayashi; Yukiho Kobayashi; Dörthe A. Kesper; Andrea Vortkamp; David P. Rice; David P. Rice

2017-01-01

Loss-of-function mutations in GLI3 and IHH cause craniosynostosis and reduced osteogenesis, respectively. In this study, we show that Ihh ligand, the receptor Ptch1 and Gli transcription factors are differentially expressed in embryonic mouse calvaria osteogenic condensations. We show that in both Ihh−/− and Gli3Xt−J/Xt−J embryonic mice, the normal gene expression architecture is lost and this results in disorganized calvarial bone development. RUNX2 is a master regulatory transcription facto...
Regulation of sonic hedgehog-GLI1 downstream target genes PTCH1, Cyclin D2, Plakoglobin, PAX6 and NKX2.2 and their epigenetic status in medulloblastoma and astrocytoma

International Nuclear Information System (INIS)

Shahi, Mehdi H; Afzal, Mohammad; Sinha, Subrata; Eberhart, Charles G; Rey, Juan A; Fan, Xing; Castresana, Javier S

2010-01-01

The Sonic hedgehog (Shh) signaling pathway is critical for cell growth and differentiation. Impairment of this pathway can result in both birth defects and cancer. Despite its importance in cancer development, the Shh pathway has not been thoroughly investigated in tumorigenesis of brain tumors. In this study, we sought to understand the regulatory roles of GLI1, the immediate downstream activator of the Shh signaling pathway on its downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6 in medulloblastoma and astrocytic tumors. We silenced GLI1 expression in medulloblastoma and astrocytic cell lines by transfection of siRNA against GLI1. Subsequently, we performed RT-PCR and quantitative real time RT-PCR (qRT-PCR) to assay the expression of downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6. We also attempted to correlate the pattern of expression of GLI1 and its regulated genes in 14 cell lines and 41 primary medulloblastoma and astrocytoma tumor samples. We also assessed the methylation status of the Cyclin D2 and PTCH1 promoters in these 14 cell lines and 58 primary tumor samples. Silencing expression of GLI1 resulted up-regulation of all target genes in the medulloblastoma cell line, while only PTCH1 was up-regulated in astrocytoma. We also observed methylation of the cyclin D2 promoter in a significant number of astrocytoma cell lines (63%) and primary astrocytoma tumor samples (32%), but not at all in any medulloblastoma samples. PTCH1 promoter methylation was less frequently observed than Cyclin D2 promoter methylation in astrocytomas, and not at all in medulloblastomas. Our results demonstrate different regulatory mechanisms of Shh-GLI1 signaling. These differences vary according to the downstream target gene affected, the origin of the tissue, as well as epigenetic regulation of some of these genes
Regulation of sonic hedgehog-GLI1 downstream target genes PTCH1, Cyclin D2, Plakoglobin, PAX6 and NKX2.2 and their epigenetic status in medulloblastoma and astrocytoma

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Eberhart Charles G

2010-11-01

Full Text Available Abstract Background The Sonic hedgehog (Shh signaling pathway is critical for cell growth and differentiation. Impairment of this pathway can result in both birth defects and cancer. Despite its importance in cancer development, the Shh pathway has not been thoroughly investigated in tumorigenesis of brain tumors. In this study, we sought to understand the regulatory roles of GLI1, the immediate downstream activator of the Shh signaling pathway on its downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6 in medulloblastoma and astrocytic tumors. Methods We silenced GLI1 expression in medulloblastoma and astrocytic cell lines by transfection of siRNA against GLI1. Subsequently, we performed RT-PCR and quantitative real time RT-PCR (qRT-PCR to assay the expression of downstream target genes PTCH1, Cyclin D2, Plakoglobin, NKX2.2 and PAX6. We also attempted to correlate the pattern of expression of GLI1 and its regulated genes in 14 cell lines and 41 primary medulloblastoma and astrocytoma tumor samples. We also assessed the methylation status of the Cyclin D2 and PTCH1 promoters in these 14 cell lines and 58 primary tumor samples. Results Silencing expression of GLI1 resulted up-regulation of all target genes in the medulloblastoma cell line, while only PTCH1 was up-regulated in astrocytoma. We also observed methylation of the cyclin D2 promoter in a significant number of astrocytoma cell lines (63% and primary astrocytoma tumor samples (32%, but not at all in any medulloblastoma samples. PTCH1 promoter methylation was less frequently observed than Cyclin D2 promoter methylation in astrocytomas, and not at all in medulloblastomas. Conclusions Our results demonstrate different regulatory mechanisms of Shh-GLI1 signaling. These differences vary according to the downstream target gene affected, the origin of the tissue, as well as epigenetic regulation of some of these genes.
Regulation of Calvarial Osteogenesis by Concomitant De-repression of GLI3 and Activation of IHH Targets

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Lotta K. Veistinen

2017-12-01

Full Text Available Loss-of-function mutations in GLI3 and IHH cause craniosynostosis and reduced osteogenesis, respectively. In this study, we show that Ihh ligand, the receptor Ptch1 and Gli transcription factors are differentially expressed in embryonic mouse calvaria osteogenic condensations. We show that in both Ihh−/− and Gli3Xt−J/Xt−J embryonic mice, the normal gene expression architecture is lost and this results in disorganized calvarial bone development. RUNX2 is a master regulatory transcription factor controlling osteogenesis. In the absence of Gli3, RUNX2 isoform II and IHH are upregulated, and RUNX2 isoform I downregulated. This is consistent with the expanded and aberrant osteogenesis observed in Gli3Xt−J/Xt−J mice, and consistent with Runx2-I expression by relatively immature osteoprogenitors. Ihh−/− mice exhibited small calvarial bones and HH target genes, Ptch1 and Gli1, were absent. This indicates that IHH is the functional HH ligand, and that it is not compensated by another HH ligand. To decipher the roles and potential interaction of Gli3 and Ihh, we generated Ihh−/−;Gli3Xt−J/Xt−J compound mutant mice. Even in the absence of Ihh, Gli3 deletion was sufficient to induce aberrant precocious ossification across the developing suture, indicating that the craniosynostosis phenotype of Gli3Xt−J/Xt−J mice is not dependent on IHH ligand. Also, we found that Ihh was not required for Runx2 expression as the expression of RUNX2 target genes was unaffected by deletion of Ihh. To test whether RUNX2 has a role upstream of IHH, we performed RUNX2 siRNA knock down experiments in WT calvarial osteoblasts and explants and found that Ihh expression is suppressed. Our results show that IHH is the functional HH ligand in the embryonic mouse calvaria osteogenic condensations, where it regulates the progression of osteoblastic differentiation. As GLI3 represses the expression of Runx2-II and Ihh, and also elevates the Runx2-I expression
Regulation of Calvarial Osteogenesis by Concomitant De-repression of GLI3 and Activation of IHH Targets.

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Veistinen, Lotta K; Mustonen, Tuija; Hasan, Md Rakibul; Takatalo, Maarit; Kobayashi, Yukiho; Kesper, Dörthe A; Vortkamp, Andrea; Rice, David P

2017-01-01

Loss-of-function mutations in GLI3 and IHH cause craniosynostosis and reduced osteogenesis, respectively. In this study, we show that Ihh ligand, the receptor Ptch1 and Gli transcription factors are differentially expressed in embryonic mouse calvaria osteogenic condensations. We show that in both Ihh -/- and Gli3 Xt - J / Xt - J embryonic mice, the normal gene expression architecture is lost and this results in disorganized calvarial bone development. RUNX2 is a master regulatory transcription factor controlling osteogenesis. In the absence of Gli3 , RUNX2 isoform II and IHH are upregulated, and RUNX2 isoform I downregulated. This is consistent with the expanded and aberrant osteogenesis observed in Gli3 Xt - J / Xt - J mice, and consistent with Runx2-I expression by relatively immature osteoprogenitors. Ihh -/- mice exhibited small calvarial bones and HH target genes, Ptch1 and Gli1 , were absent. This indicates that IHH is the functional HH ligand, and that it is not compensated by another HH ligand. To decipher the roles and potential interaction of Gli3 and Ihh, we generated Ihh -/- ; Gli3 Xt - J / Xt - J compound mutant mice. Even in the absence of Ihh, Gli3 deletion was sufficient to induce aberrant precocious ossification across the developing suture, indicating that the craniosynostosis phenotype of Gli3 Xt - J / Xt - J mice is not dependent on IHH ligand. Also, we found that Ihh was not required for Runx2 expression as the expression of RUNX2 target genes was unaffected by deletion of Ihh . To test whether RUNX2 has a role upstream of IHH, we performed RUNX2 siRNA knock down experiments in WT calvarial osteoblasts and explants and found that Ihh expression is suppressed. Our results show that IHH is the functional HH ligand in the embryonic mouse calvaria osteogenic condensations, where it regulates the progression of osteoblastic differentiation. As GLI3 represses the expression of Runx2-II and Ihh , and also elevates the Runx2-I expression, and as IHH
Pituitary adenylyl cyclase activating polypeptide inhibits gli1 gene expression and proliferation in primary medulloblastoma derived tumorsphere cultures

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Dong Hongmei

2010-12-01

Full Text Available Abstract Background Hedgehog (HH signaling is critical for the expansion of granule neuron precursors (GNPs within the external granular layer (EGL during cerebellar development. Aberrant HH signaling within GNPs is thought to give rise to medulloblastoma (MB - the most commonly-observed form of malignant pediatric brain tumor. Evidence in both invertebrates and vertebrates indicates that cyclic AMP-dependent protein kinase A (PKA antagonizes HH signalling. Receptors specific for the neuropeptide pituitary adenylyl cyclase activating polypeptide (PACAP, gene name ADCYAP1 are expressed in GNPs. PACAP has been shown to protect GNPs from apoptosis in vitro, and to interact with HH signaling to regulate GNP proliferation. PACAP/ptch1 double mutant mice exhibit an increased incidence of MB compared to ptch1 mice, indicating that PACAP may regulate HH pathway-mediated MB pathogenesis. Methods Primary MB tumorsphere cultures were prepared from thirteen ptch1+/-/p53+/- double mutant mice and treated with the smoothened (SMO agonist purmorphamine, the SMO antagonist SANT-1, the neuropeptide PACAP, the PKA activator forskolin, and the PKA inhibitor H89. Gene expression of gli1 and [3H]-thymidine incorporation were assessed to determine drug effects on HH pathway activity and proliferation, respectively. PKA activity was determined in cell extracts by Western blotting using a phospho-PKA substrate antibody. Results Primary tumor cells cultured for 1-week under serum-free conditions grew as tumorspheres and were found to express PAC1 receptor transcripts. Gli1 gene expression was significantly reduced by SANT-1, PACAP and forskolin, but was unaffected by purmorphamine. The attenuation of gli1 gene expression by PACAP was reversed by the PKA inhibitor H89, which also blocked PKA activation. Treatment of tumorsphere cultures with PACAP, forskolin, and SANT-1 for 24 or 48 hours reduced proliferation. Conclusions Primary tumorspheres derived from ptch1+/-/p53
Pituitary adenylyl cyclase activating polypeptide inhibits gli1 gene expression and proliferation in primary medulloblastoma derived tumorsphere cultures

International Nuclear Information System (INIS)

Cohen, Joseph R; Resnick, Daniel Z; Niewiadomski, Pawel; Dong, Hongmei; Liau, Linda M; Waschek, James A

2010-01-01

Hedgehog (HH) signaling is critical for the expansion of granule neuron precursors (GNPs) within the external granular layer (EGL) during cerebellar development. Aberrant HH signaling within GNPs is thought to give rise to medulloblastoma (MB) - the most commonly-observed form of malignant pediatric brain tumor. Evidence in both invertebrates and vertebrates indicates that cyclic AMP-dependent protein kinase A (PKA) antagonizes HH signalling. Receptors specific for the neuropeptide pituitary adenylyl cyclase activating polypeptide (PACAP, gene name ADCYAP1) are expressed in GNPs. PACAP has been shown to protect GNPs from apoptosis in vitro, and to interact with HH signaling to regulate GNP proliferation. PACAP/ptch1 double mutant mice exhibit an increased incidence of MB compared to ptch1 mice, indicating that PACAP may regulate HH pathway-mediated MB pathogenesis. Primary MB tumorsphere cultures were prepared from thirteen ptch1 +/- /p53 +/- double mutant mice and treated with the smoothened (SMO) agonist purmorphamine, the SMO antagonist SANT-1, the neuropeptide PACAP, the PKA activator forskolin, and the PKA inhibitor H89. Gene expression of gli1 and [ 3 H]-thymidine incorporation were assessed to determine drug effects on HH pathway activity and proliferation, respectively. PKA activity was determined in cell extracts by Western blotting using a phospho-PKA substrate antibody. Primary tumor cells cultured for 1-week under serum-free conditions grew as tumorspheres and were found to express PAC1 receptor transcripts. Gli1 gene expression was significantly reduced by SANT-1, PACAP and forskolin, but was unaffected by purmorphamine. The attenuation of gli1 gene expression by PACAP was reversed by the PKA inhibitor H89, which also blocked PKA activation. Treatment of tumorsphere cultures with PACAP, forskolin, and SANT-1 for 24 or 48 hours reduced proliferation. Primary tumorspheres derived from ptch1 +/- /p53 +/- mice exhibit constitutive HH pathway activity
Anticancer drugs and the regulation of Hedgehog genes GLI1 and PTCH1, a comparative study in nonmelanoma skin cancer cell lines

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Olesen, Uffe H; Bojesen, Sophie; Gehl, Julie

2017-01-01

Nonmelanoma skin cancer is the most common cancer in humans, comprising mainly basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). BCC proliferation is highly dependent on the Hedgehog signaling pathway. We aimed to investigate a panel of anticancer drugs with known activity against skin...... of immortalized keratinocytes (HaCaT), BCC (UWBCC1 and BCC77015), and SCC (A431 and SCC25) cell lines. The impact of treatment on the regulation of Hedgehog pathway target genes (GLI1 and PTCH1), measured by real-time PCR, was compared between UWBCC1 and HaCaT. Varying cell line sensitivity profiles...... to the examined anticancer drugs were observed. Generally, 24-h drug exposure was sufficient to reduce cell viability. We found that 5-FU, MTX, and cisplatin significantly downregulated the expression of two genes controlled by the Hedgehog pathway (≤25-, 2.9-, and 12.5-fold, respectively, for GLI1 in UWBCC1...
GLI1 is involved in cell cycle regulation and proliferation of NT2 embryonal carcinoma stem cells

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Vestergaard, Janni; Lind-Thomsen, Allan; Pedersen, Mikkel W.

2008-01-01

of altered HH signaling are interpreted by specific cell types. We have investigated the role of the HH transcription factor glioma-associated oncogene homolog 1 (GLI1) in the human Ntera2=D1 (NT2) embryonal carcinoma stem cell line. The study revealed that expression of GLI1 and its direct transcriptional......1 phase cyclins. In conclusion, our results suggest that GLI1 is involved in cell cycle and proliferation control in the embryonal carcinoma stem cell line NT2....... target Patched (PTCH) is downregulated in the early stages of retinoic acid-induced neuronal differentiation of NT2 cells. To identify transcriptional targets of the HH transcription factor GLI1 in NT2 cells, we performed global expression profiling following GLI1 RNA interference (RNAi). Of the similar...
AMP-Activated Protein Kinase Directly Phosphorylates and Destabilizes Hedgehog Pathway Transcription Factor GLI1 in Medulloblastoma

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Yen-Hsing Li

2015-07-01

Full Text Available The Hedgehog (Hh pathway regulates cell differentiation and proliferation during development by controlling the Gli transcription factors. Cell fate decisions and progression toward organ and tissue maturity must be coordinated, and how an energy sensor regulates the Hh pathway is not clear. AMP-activated protein kinase (AMPK is an important sensor of energy stores and controls protein synthesis and other energy-intensive processes. AMPK is directly responsive to intracellular AMP levels, inhibiting a wide range of cell activities if ATP is low and AMP is high. Thus, AMPK can affect development by influencing protein synthesis and other processes needed for growth and differentiation. Activation of AMPK reduces GLI1 protein levels and stability, thus blocking Sonic-hedgehog-induced transcriptional activity. AMPK phosphorylates GLI1 at serines 102 and 408 and threonine 1074. Mutation of these three sites into alanine prevents phosphorylation by AMPK. This leads to increased GLI1 protein stability, transcriptional activity, and oncogenic potency.
Blocking signaling at the level of GLI regulates downstream gene expression and inhibits proliferation of canine osteosarcoma cells.

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Shahi, Mehdi Hayat; Holt, Roseline; Rebhun, Robert B

2014-01-01

The Hedgehog-GLI signaling pathway is active in a variety of human malignancies and is known to contribute to the growth and survival of human osteosarcoma cells. In this study, we examined the expression and regulation of GLI transcription factors in multiple canine osteosarcoma cell lines and analyzed the effects of inhibiting GLI with GANT61, a GLI-specific inhibitor. Compared with normal canine osteoblasts, real-time PCR showed that GLI1 and GLI2 were highly expressed in two out of three cell lines and correlated with downstream target gene expression of PTCH1and PAX6. Treatment of canine osteosarcoma cells with GANT61 resulted in decreased expression of GLI1, GLI2, PTCH1, and PAX6. Furthermore, GANT61 inhibited proliferation and colony formation in all three canine osteosarcoma cell lines. The finding that GLI signaling activity is present and active in canine osteosarcoma cells suggests that spontaneously arising osteosarcoma in dogs might serve as a good model for future preclinical testing of GLI inhibitors.
Blocking signaling at the level of GLI regulates downstream gene expression and inhibits proliferation of canine osteosarcoma cells.

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Mehdi Hayat Shahi

Full Text Available The Hedgehog-GLI signaling pathway is active in a variety of human malignancies and is known to contribute to the growth and survival of human osteosarcoma cells. In this study, we examined the expression and regulation of GLI transcription factors in multiple canine osteosarcoma cell lines and analyzed the effects of inhibiting GLI with GANT61, a GLI-specific inhibitor. Compared with normal canine osteoblasts, real-time PCR showed that GLI1 and GLI2 were highly expressed in two out of three cell lines and correlated with downstream target gene expression of PTCH1and PAX6. Treatment of canine osteosarcoma cells with GANT61 resulted in decreased expression of GLI1, GLI2, PTCH1, and PAX6. Furthermore, GANT61 inhibited proliferation and colony formation in all three canine osteosarcoma cell lines. The finding that GLI signaling activity is present and active in canine osteosarcoma cells suggests that spontaneously arising osteosarcoma in dogs might serve as a good model for future preclinical testing of GLI inhibitors.
Synergism between Hedgehog-GLI and EGFR signaling in Hedgehog-responsive human medulloblastoma cells induces downregulation of canonical Hedgehog-target genes and stabilized expression of GLI1.

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Frank Götschel

Full Text Available Aberrant activation of Hedgehog (HH signaling has been identified as a key etiologic factor in many human malignancies. Signal strength, target gene specificity, and oncogenic activity of HH signaling depend profoundly on interactions with other pathways, such as epidermal growth factor receptor-mediated signaling, which has been shown to cooperate with HH/GLI in basal cell carcinoma and pancreatic cancer. Our experimental data demonstrated that the Daoy human medulloblastoma cell line possesses a fully inducible endogenous HH pathway. Treatment of Daoy cells with Sonic HH or Smoothened agonist induced expression of GLI1 protein and simultaneously prevented the processing of GLI3 to its repressor form. To study interactions between HH- and EGF-induced signaling in greater detail, time-resolved measurements were carried out and analyzed at the transcriptomic and proteomic levels. The Daoy cells responded to the HH/EGF co-treatment by downregulating GLI1, PTCH, and HHIP at the transcript level; this was also observed when Amphiregulin (AREG was used instead of EGF. We identified a novel crosstalk mechanism whereby EGFR signaling silences proteins acting as negative regulators of HH signaling, as AKT- and ERK-signaling independent process. EGFR/HH signaling maintained high GLI1 protein levels which contrasted the GLI1 downregulation on the transcript level. Conversely, a high-level synergism was also observed, due to a strong and significant upregulation of numerous canonical EGF-targets with putative tumor-promoting properties such as MMP7, VEGFA, and IL-8. In conclusion, synergistic effects between EGFR and HH signaling can selectively induce a switch from a canonical HH/GLI profile to a modulated specific target gene profile. This suggests that there are more wide-spread, yet context-dependent interactions, between HH/GLI and growth factor receptor signaling in human malignancies.
The transcription factor Foxc1 is necessary for Ihh-Gli2-regulated endochondral ossification.

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Yoshida, Michiko; Hata, Kenji; Takashima, Rikako; Ono, Koichiro; Nakamura, Eriko; Takahata, Yoshifumi; Murakami, Tomohiko; Iseki, Sachiko; Takano-Yamamoto, Teruko; Nishimura, Riko; Yoneda, Toshiyuki

2015-03-26

Indian hedgehog (Ihh) regulates endochondral ossification in both a parathyroid hormone-related protein (PTHrP)-dependent and -independent manner by activating transcriptional mediator Gli2. However, the molecular mechanisms underlying these processes remain elusive. Here by using in vivo microarray analysis, we identify forkhead box C1 (Foxc1) as a transcriptional partner of Gli2. Foxc1 stimulates expression of Ihh target genes, including PTHrP and Col10a1, through its physical and functional interaction with Gli2. Conversely, a dominant negative Foxc1 inhibits the Ihh target gene expression. In a spontaneous loss of Foxc1 function mouse (Foxc1(ch/ch)), endochondral ossification is delayed and the expression of Ihh target genes inhibited. Moreover, the pathological Foxc1 missense mutation observed in the Axenfeld-Rieger syndrome impairs Gli2-Foxc1 association as well as Ihh function. Our findings suggest that Foxc1 is an important transcriptional partner of Ihh-Gli2 signalling during endochondral ossification, and that disruption of the Foxc1-Gli2 interaction causes skeletal abnormalities observed in the Axenfeld-Rieger syndrome.
Gli3 acts as a repressor downstream of Ihh in regulating two distinct steps of chondrocyte differentiation.

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Koziel, Lydia; Wuelling, Manuela; Schneider, Sabine; Vortkamp, Andrea

2005-12-01

During endochondral ossification, the secreted growth factor Indian hedgehog (Ihh) regulates several differentiation steps. It interacts with a second secreted factor, parathyroid hormone-related protein (PTHrP), to regulate the onset of hypertrophic differentiation, and it regulates chondrocyte proliferation and ossification of the perichondrium independently of PTHrP. To investigate how the Ihh signal is translated in the different target tissues, we analyzed the role of the zinc-finger transcription factor Gli3, which acts downstream of hedgehog signals in other organs. Loss of Gli3 in Ihh mutants restores chondrocyte proliferation and delays the accelerated onset of hypertrophic differentiation observed in Ihh-/- mutants. Furthermore the expression of the Ihh target genes patched (Ptch) and PTHrP is reactivated in Ihh-/-;Gli3-/- mutants. Gli3 seems thus to act as a strong repressor of Ihh signals in regulating chondrocyte differentiation. In addition, loss of Gli3 in mice that overexpress Ihh in chondrocytes accelerates the onset of hypertrophic differentiation by reducing the domain and possibly the level of PTHrP expression. Careful analysis of chondrocyte differentiation in Gli3-/- mutants revealed that Gli3 negatively regulates the differentiation of distal, low proliferating chondrocytes into columnar, high proliferating cells. Our results suggest a model in which the Ihh/Gli3 system regulates two distinct steps of chondrocyte differentiation: (1) the switch from distal into columnar chondrocytes is repressed by Gli3 in a PTHrP-independent mechanism; (2) the transition from proliferating into hypertrophic chondrocytes is regulated by Gli3-dependent expression of PTHrP. Furthermore, by regulating distal chondrocyte differentiation, Gli3 seems to position the domain of PTHrP expression.
Targeting GLI by GANT61 involves mechanisms dependent on inhibition of both transcription and DNA licensing.

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Zhang, Ruowen; Wu, Jiahui; Ferrandon, Sylvain; Glowacki, Katie J; Houghton, Janet A

2016-12-06

The GLI genes are transcription factors and in cancers are oncogenes, aberrantly and constitutively activated. GANT61, a specific GLI inhibitor, has induced extensive cytotoxicity in human models of colon cancer. The FOXM1 promoter was determined to be a transcriptional target of GLI1. In HT29 cells, inhibition of GLI1 binding at the GLI consensus sequence by GANT61 led to inhibited binding of Pol II, the pause-release factors DSIF, NELF and p-TEFb. The formation of R-loops (RNA:DNA hybrids, ssDNA), were reduced by GANT61 at the FOXM1 promoter. Pretreatment of HT29 cells with α-amanitin reduced GANT61-induced γH2AX foci. Co-localization of GLI1 and BrdU foci, inhibited by GANT61, indicated GLI1 and DNA replication to be linked. By co-immunoprecipitation and confocal microscopy, GLI1 co-localized with the DNA licensing factors ORC4, CDT1, and MCM2. Significant co-localization of GLI1 and ORC4 was inhibited by GANT61, and enrichment of ORC4 occurred at the GLI binding site in the FOXM1 promoter. CDT1 was found to be a transcription target of GLI1. Overexpression of CDT1 in HT29 and SW480 cells reduced GANT61-induced cell death, gH2AX foci, and cleavage of caspase-3. Data demonstrate involvement of transcription and of DNA replication licensing factors by non-transcriptional and transcriptional mechanisms in the GLI-dependent mechanism of action of GANT61.
Downregulation of the Sonic Hedgehog/Gli pathway transcriptional target Neogenin-1 is associated with basal cell carcinoma aggressiveness.

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Casas, Bárbara S; Adolphe, Christelle; Lois, Pablo; Navarrete, Nelson; Solís, Natalia; Bustamante, Eva; Gac, Patricio; Cabané, Patricio; Gallegos, Ivan; Wainwright, Brandon J; Palma, Verónica

2017-10-13

Basal Cell Carcinoma (BCC) is one of the most diagnosed cancers worldwide. It develops due to an unrestrained Sonic Hedgehog (SHH) signaling activity in basal cells of the skin. Certain subtypes of BCC are more aggressive than others, although the molecular basis of this phenomenon remains unknown. We have previously reported that Neogenin-1 (NEO1) is a downstream target gene of the SHH/GLI pathway in neural tissue. Given that SHH participates in epidermal homeostasis, here we analyzed the epidermal expression of NEO1 in order to identify whether it plays a role in adult epidermis or BCC. We describe the mRNA and protein expression profile of NEO1 and its ligands (Netrin-1 and RGMA) in human and mouse control epidermis and in a broad range of human BCCs. We identify in human BCC a significant positive correlation in the levels of NEO1 receptor, NTN-1 and RGMA ligands with respect to GLI1 , the main target gene of the canonical SHH pathway. Moreover, we show via cyclopamine inhibition of the SHH/GLI pathway of ex vivo cultures that NEO1 likely functions as a downstream target of SHH/GLI signaling in the skin. We also show how Neo1 expression decreases throughout BCC progression in the K14-Cre:Ptch1 lox/lox mouse model and that aggressive subtypes of human BCC exhibit lower levels of NEO1 than non-aggressive BCC samples. Taken together, these data suggest that NEO1 is a SHH/GLI target in epidermis. We propose that NEO1 may be important in tumor onset and is then down-regulated in advanced BCC or aggressive subtypes.
HECT E3 Ubiquitin Ligase Itch Functions as a Novel Negative Regulator of Gli-Similar 3 (Glis3 Transcriptional Activity.

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Gary T ZeRuth

Full Text Available The transcription factor Gli-similar 3 (Glis3 plays a critical role in the generation of pancreatic ß cells and the regulation insulin gene transcription and has been implicated in the development of several pathologies, including type 1 and 2 diabetes and polycystic kidney disease. However, little is known about the proteins and posttranslational modifications that regulate or mediate Glis3 transcriptional activity. In this study, we identify by mass-spectrometry and yeast 2-hybrid analyses several proteins that interact with the N-terminal region of Glis3. These include the WW-domain-containing HECT E3 ubiquitin ligases, Itch, Smurf2, and Nedd4. The interaction between Glis3 and the HECT E3 ubiquitin ligases was verified by co-immunoprecipitation assays and mutation analysis. All three proteins interact through their WW-domains with a PPxY motif located in the Glis3 N-terminus. However, only Itch significantly contributed to Glis3 polyubiquitination and reduced Glis3 stability by enhancing its proteasomal degradation. Itch-mediated degradation of Glis3 required the PPxY motif-dependent interaction between Glis3 and the WW-domains of Itch as well as the presence of the Glis3 zinc finger domains. Transcription analyses demonstrated that Itch dramatically inhibited Glis3-mediated transactivation and endogenous Ins2 expression by increasing Glis3 protein turnover. Taken together, our study identifies Itch as a critical negative regulator of Glis3-mediated transcriptional activity. This regulation provides a novel mechanism to modulate Glis3-driven gene expression and suggests that it may play a role in a number of physiological processes controlled by Glis3, such as insulin transcription, as well as in Glis3-associated diseases.
The Gli2 transcriptional activator is a crucial effector for Ihh signaling in osteoblast development and cartilage vascularization.

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Joeng, Kyu Sang; Long, Fanxin

2009-12-01

Indian hedgehog (Ihh) critically regulates multiple aspects of endochondral bone development. Although it is generally believed that all Ihh functions are mediated by the Gli family of transcription activators and repressors, formal genetic proof for this notion has not been provided. Moreover, the extent to which different Gli proteins contribute to Ihh functions is not fully understood. Previous work has shown that de-repression of the Gli3 repressor is the predominant mode through which Ihh controls chondrocyte proliferation and maturation, but that osteoblast differentiation and hypertrophic cartilage vascularization require additional mechanisms. To test the involvement of Gli2 activation in these processes, we have generated a mouse strain that expresses a constitutive Gli2 activator in a Cre-dependent manner, and have attempted to rescue the Ihh-null mouse with the Gli2 activator, either alone or in combination with Gli3 removal. Here, we report that the Gli2 activator alone is sufficient to induce vascularization of the hypertrophic cartilage in the absence of Ihh but requires simultaneous removal of Gli3 to restore osteoblast differentiation. These results therefore provide direct genetic evidence that Gli2 and Gli3 collectively mediate all major aspects of Ihh function during endochondral skeletal development.
Gli2 activator function in preosteoblasts is sufficient to mediate Ihh-dependent osteoblast differentiation, whereas the repressor function of Gli2 is dispensable for endochondral ossification.

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Kesper, Dörthe Andrea; Didt-Koziel, Lydia; Vortkamp, Andrea

2010-06-01

Signaling of Indian hedgehog (Ihh), one of the key regulators of endochondral ossification is mediated by transcription factors of the Gli family, Gli1, Gli2, and Gli3. Gli3 and to a lesser extent Gli2 can be proteolytically processed into short repressor proteins. Upon Ihh signaling, processing is inhibited and the full-length proteins function as activators of transcription. Gli3 has been shown to mainly act as a repressor of Ihh target genes in chondrocytes, but the role of other Gli isoforms is less clear. Analyzing mouse mutants deficient for Ihh;Gli2 or Gli3;Gli2, we show here that the Gli2 repressor has no detectable function in chondrocyte or osteoblast differentiation. Instead, Gli2 seems to act as an activator to fully induce the expression of Ihh target genes in skeletal tissues. Furthermore, we show that, in the absence of Gli3, the activator function of Gli2 is sufficient to induce Ihh-dependent osteoblast differentiation.

The transcription factor GLI1 modulates the inflammatory response during pancreatic tissue remodeling.

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Mathew, Esha; Collins, Meredith A; Fernandez-Barrena, Maite G; Holtz, Alexander M; Yan, Wei; Hogan, James O; Tata, Zachary; Allen, Benjamin L; Fernandez-Zapico, Martin E; di Magliano, Marina Pasca

2014-10-03

Pancreatic cancer, one of the deadliest human malignancies, is almost uniformly associated with a mutant, constitutively active form of the oncogene Kras. Studies in genetically engineered mouse models have defined a requirement for oncogenic KRAS in both the formation of pancreatic intraepithelial neoplasias, the most common precursor lesions to pancreatic cancer, and in the maintenance and progression of these lesions. Previous work using an inducible model allowing tissue-specific and reversible expression of oncogenic Kras in the pancreas indicates that inactivation of this GTPase at the pancreatic intraepithelial neoplasia stage promotes pancreatic tissue repair. Here, we extend these findings to identify GLI1, a transcriptional effector of the Hedgehog pathway, as a central player in pancreatic tissue repair upon Kras inactivation. Deletion of a single allele of Gli1 results in improper stromal remodeling and perdurance of the inflammatory infiltrate characteristic of pancreatic tumorigenesis. Strikingly, this partial loss of Gli1 affects activated fibroblasts in the pancreas and the recruitment of immune cells that are vital for tissue recovery. Analysis of the mechanism using expression and chromatin immunoprecipitation assays identified a subset of cytokines, including IL-6, mIL-8, Mcp-1, and M-csf (Csf1), as direct GLI1 target genes potentially mediating this phenomenon. Finally, we demonstrate that canonical Hedgehog signaling, a known regulator of Gli1 activity, is required for pancreas recovery. Collectively, these data delineate a new pathway controlling tissue repair and highlight the importance of GLI1 in regulation of the pancreatic microenvironment during this cellular process. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
Transcriptional profiles of SHH pathway genes in keratocystic odontogenic tumor and ameloblastoma.

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Gurgel, Clarissa Araújo Silva; Buim, Marcilei Eliza Cavichiolli; Carvalho, Kátia Cândido; Sales, Caroline Brandi Schlaepfer; Reis, Mitermayer Galvão; de Souza, Renata Oliveira; de Faro Valverde, Ludmila; de Azevedo, Roberto Almeida; Dos Santos, Jean Nunes; Soares, Fernando Augusto; Ramos, Eduardo Antônio Gonçalves

2014-09-01

Sonic hedgehog (SHH) pathway activation has been identified as a key factor in the development of many types of tumors, including odontogenic tumors. Our study examined the expression of genes in the SHH pathway to characterize their roles in the pathogenesis of keratocystic odontogenic tumors (KOT) and ameloblastomas (AB). We quantified the expression of SHH, SMO, PTCH1, SUFU, GLI1, CCND1, and BCL2 genes by qPCR in a total of 23 KOT, 11 AB, and three non-neoplastic oral mucosa (NNM). We also measured the expression of proteins related to this pathway (CCND1 and BCL2) by immunohistochemistry. We observed overexpression of SMO, PTCH1, GLI1, and CCND1 genes in both KOT (23/23) and AB (11/11). However, we did not detect expression of the SHH gene in 21/23 KOT and 10/11 AB tumors. Low levels of the SUFU gene were expressed in KOT (P = 0.0199) and AB (P = 0.0127) relative to the NNM. Recurrent KOT exhibited high levels of SMO (P = 0.035), PTCH1 (P = 0.048), CCND1 (P = 0.048), and BCL2 (P = 0.045) transcripts. Using immunolabeling of CCND1, we observed no statistical difference between primary and recurrent KOT (P = 0.8815), sporadic and NBCCS-KOT (P = 0.7688), and unicystic and solid AB (P = 0.7521). Overexpression of upstream (PTCH1 and SMO) and downstream (GLI1, CCND1 and BCL2) genes in the SHH pathway leads to the constitutive activation of this pathway in KOT and AB and may suggest a mechanism for the development of these types of tumors. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
Gli3 is a negative regulator of Tas1r3-expressing taste cells

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Jyotaki, Masafumi; Redding, Kevin; Jiang, Peihua

2018-01-01

Mouse taste receptor cells survive from 3–24 days, necessitating their regeneration throughout adulthood. In anterior tongue, sonic hedgehog (SHH), released by a subpopulation of basal taste cells, regulates transcription factors Gli2 and Gli3 in stem cells to control taste cell regeneration. Using single-cell RNA-Seq we found that Gli3 is highly expressed in Tas1r3-expressing taste receptor cells and Lgr5+ taste stem cells in posterior tongue. By PCR and immunohistochemistry we found that Gli3 was expressed in taste buds in all taste fields. Conditional knockout mice lacking Gli3 in the posterior tongue (Gli3CKO) had larger taste buds containing more taste cells than did control wild-type (Gli3WT) mice. In comparison to wild-type mice, Gli3CKO mice had more Lgr5+ and Tas1r3+ cells, but fewer type III cells. Similar changes were observed ex vivo in Gli3CKO taste organoids cultured from Lgr5+ taste stem cells. Further, the expression of several taste marker and Gli3 target genes was altered in Gli3CKO mice and/or organoids. Mirroring these changes, Gli3CKO mice had increased lick responses to sweet and umami stimuli, decreased lick responses to bitter and sour taste stimuli, and increased glossopharyngeal taste nerve responses to sweet and bitter compounds. Our results indicate that Gli3 is a suppressor of stem cell proliferation that affects the number and function of mature taste cells, especially Tas1r3+ cells, in adult posterior tongue. Our findings shed light on the role of the Shh pathway in adult taste cell regeneration and may help devise strategies for treating taste distortions from chemotherapy and aging. PMID:29415007
Complementary Gli activity mediates early patterning of the mouse visual system.

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Furimsky, Marosh; Wallace, Valerie A

2006-03-01

The Sonic hedgehog (Shh) signaling pathway plays a key role in the development of the vertebrate central nervous system, including the eye. This pathway is mediated by the Gli transcription factors (Gli1, Gli2, and Gli3) that differentially activate and repress the expression of specific downstream target genes. In this study, we investigated the roles of the three vertebrate Glis in mediating midline Shh signaling in early ocular development. We examined the ocular phenotypes of Shh and Gli combination mutant mouse embryos and monitored proximodistal and dorsoventral patterning by the expression of specific eye development regulatory genes using in situ hybridization. We show that midline Shh signaling relieves the repressor activity of Gli3 adjacent to the midline and then promotes eye pattern formation through the nonredundant activities of all three Gli proteins. Gli3, in particular, is required to specify the dorsal optic stalk and to define the boundary between the optic stalk and the optic cup.
New mutations and an updated database for the patched-1 (PTCH1) gene.

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Reinders, Marie G; van Hout, Antonius F; Cosgun, Betûl; Paulussen, Aimée D; Leter, Edward M; Steijlen, Peter M; Mosterd, Klara; van Geel, Michel; Gille, Johan J

2018-05-01

Basal cell nevus syndrome (BCNS) is an autosomal dominant disorder characterized by multiple basal cell carcinomas (BCCs), maxillary keratocysts, and cerebral calcifications. BCNS most commonly is caused by a germline mutation in the patched-1 (PTCH1) gene. PTCH1 mutations are also described in patients with holoprosencephaly. We have established a locus-specific database for the PTCH1 gene using the Leiden Open Variation Database (LOVD). We included 117 new PTCH1 variations, in addition to 331 previously published unique PTCH1 mutations. These new mutations were found in 141 patients who had a positive PTCH1 mutation analysis in either the VU University Medical Centre (VUMC) or Maastricht University Medical Centre (MUMC) between 1995 and 2015. The database contains 331 previously published unique PTCH1 mutations and 117 new PTCH1 variations. We have established a locus-specific database for the PTCH1 gene using the Leiden Open Variation Database (LOVD). The database provides an open collection for both clinicians and researchers and is accessible online at http://www.lovd.nl/PTCH1. © 2018 The Authors. Molecular Genetics & Genomic Medicine published by Wiley Periodicals, Inc.
Differential requirements for Gli2 and Gli3 in the regional specification of the mouse hypothalamus

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Roberta eHaddad-Tóvolli

2015-03-01

Full Text Available Secreted protein Sonic hedgehog (Shh ventralizes the neural tube by modulating the crucial balance between activating and repressing functions (GliA, GliR of transcription factors Gli2 and Gli3. This balance—the Shh-Gli code—is species- and context-dependent and has been elucidated for the mouse spinal cord. The hypothalamus, a forebrain region regulating vital functions like homeostasis and hormone secretion, shows dynamic and intricate Shh expression as well as complex regional differentiation. Here we asked if particular combinations of Gli2 and Gli3 and of GliA and GliR functions contribute to the variety of hypothalamic regions, i.e. we wanted to clarify the hypothalamic version of the Shh-Gli code. Based on mouse mutant analysis, we show that: 1 hypothalamic regional heterogeneity is based in part on differentially stringent requirements for Gli2 or Gli3; 2 another source of diversity are differential requirements for Shh of neural vs non-neural origin; 3 Gli2 is indispensable for the specification of a medial progenitor domain generating several essential hypothalamic nuclei plus the pituitary and median eminence; 4 the suppression of Gli3R by neural and non-neural Shh is essential for hypothalamic specification. Finally, we have mapped our results on a recent model which considers the hypothalamus as a transverse region with alar and basal portions. Our data confirm the model and are explained by it.
Hedgehog signaling pathway is active in GBM with GLI1 mRNA expression showing a single continuous distribution rather than discrete high/low clusters.

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Chandra, Vikas; Das, Tapojyoti; Gulati, Puneet; Biswas, Nidhan K; Rote, Sarang; Chatterjee, Uttara; Ghosh, Samarendra N; Deb, Sumit; Saha, Suniti K; Chowdhury, Anup K; Ghosh, Subhashish; Rudin, Charles M; Mukherjee, Ankur; Basu, Analabha; Dhara, Surajit

2015-01-01

Hedgehog (Hh) signaling pathway is a valid therapeutic target in a wide range of malignancies. We focus here on glioblastoma multiforme (GBM), a lethal malignancy of the central nervous system (CNS). By analyzing RNA-sequencing based transcriptomics data on 149 clinical cases of TCGA-GBM database we show here a strong correlation (r = 0.7) between GLI1 and PTCH1 mRNA expression--as a hallmark of the canonical Hh-pathway activity in this malignancy. GLI1 mRNA expression varied in 3 orders of magnitude among the GBM patients of the same cohort showing a single continuous distribution-unlike the discrete high/low-GLI1 mRNA expressing clusters of medulloblastoma (MB). When compared with MB as a reference, the median GLI1 mRNA expression in GBM appeared 14.8 fold lower than that of the "high-Hh" cluster of MB but 5.6 fold higher than that of the "low-Hh" cluster of MB. Next, we demonstrated statistically significant up- and down-regulation of GLI1 mRNA expressions in GBM patient-derived low-passage neurospheres in vitro by sonic hedgehog ligand-enriched conditioned media (shh-CM) and by Hh-inhibitor drug vismodegib respectively. We also showed clinically achievable dose (50 μM) of vismodegib alone to be sufficient to induce apoptosis and cell cycle arrest in these low-passage GBM neurospheres in vitro. Vismodegib showed an effect on the neurospheres, both by down-regulating GLI1 mRNA expression and by inducing apoptosis/cell cycle arrest, irrespective of their relative endogenous levels of GLI1 mRNA expression. We conclude from our study that this single continuous distribution pattern of GLI1 mRNA expression technically puts almost all GBM patients in a single group rather than discrete high- or low-clusters in terms of Hh-pathway activity. That is suggestive of therapies with Hh-pathway inhibitor drugs in this malignancy without a need for further stratification of patients on the basis of relative levels of Hh-pathway activity among them.
Correlation of hedgehog signal activation with chemoradiotherapy sensitivity and survival in esophageal squamous cell carcinomas

International Nuclear Information System (INIS)

Zhu Weiguo; You Zhenbin; Li Tao; Yu Changhua; Tao Guangzhou; Hu Mingli; Chen Xiaofei

2011-01-01

The objective of this study was to investigate the significance of hedgehog signaling pathway in chemoradiotherapy sensitivity and its effect on the prognosis of esophageal squamous cell carcinoma. In the present study, we used the method of immunohistochemistry to examine the expression status of two hedgehog components, PTCH1 and glioma-associated oncogene GLI-1, in 100 pre-treated biopsy specimens of esophageal squamous cell carcinoma patients treated with definitive chemoradiotherapy. We find that high levels of PTCH1 and GLI-1 were detected in 76.0 and 72.0% of esophageal squamous cell carcinoma, respectively. Significant associations of high PTCH1 and GLI-1 expression with large tumor size (both P=0.01), locoregional progression (P=0.001 and 0.003, respectively) and the lack of complete response to chemoradiotherapy (P=0.008 and 0.01, respectively) were observed. Univariate analysis revealed that high PTCH1 and GLI-1 expression was associated with poor locoregional progression-free survival, distant progression-free survival and overall survival. Furthermore, esophageal squamous cell carcinoma patients with high PTCH1 and GLI-1 expression have the shorter survival time than the subgroups with negative and low PTCH1 and GLI-1 expression. In multivariate analysis, PTCH1 and GLI-1 expression status were both evaluated as independent prognostic factors for locoregional progression-free survival, distant progression-free survival and overall survival. These findings suggest an important role for the activation of hedgehog signaling in esophageal squamous cell carcinoma progression and that PTCH1 and GLI-1 expression may be significantly associated with esophageal squamous cell carcinoma resistance to chemoradiotherapy. (author)
PTCH1 gene haplotype association with basal cell carcinoma after transplantation.

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Begnini, A; Tessari, G; Turco, A; Malerba, G; Naldi, L; Gotti, E; Boschiero, L; Forni, A; Rugiu, C; Piaserico, S; Fortina, A B; Brunello, A; Cascone, C; Girolomoni, G; Gomez Lira, M

2010-08-01

Basal cell carcinoma (BCC) is 10 times more frequent in organ transplant recipients (OTRs) than in the general population. Factors in OTRs conferring increased susceptibility to BCC include ultraviolet radiation exposure, immunosuppression, viral infections such as human papillomavirus, phototype and genetic predisposition. The PTCH1 gene is a negative regulator of the hedgehog pathway, that provides mitogenic signals to basal cells in skin. PTCH1 gene mutations cause naevoid BCC syndrome, and contribute to the development of sporadic BCC and other types of cancers. Associations have been reported between PTCH1 polymorphisms and BCC susceptibility in nontransplanted individuals. To search for novel common polymorphisms in the proximal 5' regulatory region upstream of PTCH1 gene exon 1B, and to investigate the possible association of PTCH1 polymorphisms and haplotypes with BCC risk after organ transplantation. Three PTCH1 single nucleotide polymorphisms (rs2297086, rs2066836 and rs357564) were analysed by restriction fragment length polymorphism analysis in 161 northern Italian OTRs (56 BCC cases and 105 controls). Two regions of the PTCH1 gene promoter were screened by heteroduplex analysis in 30 cases and 30 controls. Single locus analysis showed no significant association. Haplotype T(1686)-T(3944) appeared to confer a significantly higher risk for BCC development (odds ratio 2.98, 95% confidence interval 2.55-3.48; P = 0.001). Two novel rare polymorphisms were identified at positions 176 and 179 of the 5'UTR. Two novel alleles of the -4 (CGG)(n) microsatellite were identified. No association of this microsatellite with BCC was observed. Haplotypes containing T(1686)-T(3944) alleles were shown to be associated with an increased BCC risk in our study population. These data appear to be of great interest for further investigations in a larger group of transplant individuals. Our results do not support the hypothesis that common polymorphisms in the proximal 5
AICD Overexpression in Neuro 2A Cells Regulates Expression of PTCH1 and TRPC5

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Mithu Raychaudhuri

2011-01-01

Full Text Available Amyloid precursor protein (APP, implicated in Alzheimer's disease, is a transmembrane protein of undetermined function. APP is cleaved by gamma-secretase that releases the APP intracellular domain (AICD in the cytoplasm. In vitro and in vivo studies have implicated the role of AICD in cell signaling and transcriptional regulation of Gsk3β, KAI1, BACE1, EGFR, and other proteins. In this study, by overexpressing AICD in mouse neuroblastoma cell lines, we have demonstrated the alteration in the expressions of two proteins, patched homolog 1 (PTCH1, a receptor for sonic hedgehog signaling, and transient receptor potential cation channel subfamily C member 5 (TRPC5, a component of receptor-activated nonselective calcium permeant cation channel. Our results indicate the possibility of regulation by AICD in developmental processes as well as in the maintenance of calcium homeostasis at the transcription level.
A Novel Gli3 Enhancer Controls the Gli3 Spatiotemporal Expression Pattern through a TALE Homeodomain Protein Binding Site ▿‡

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Coy, Sarah; Caamaño, Jorge H.; Carvajal, Jaime; Cleary, Michael L.; Borycki, Anne-Gaëlle

2011-01-01

The zinc finger transcription factor Gli3 is an essential mediator of hedgehog signaling. Gli3 has a dynamic expression pattern during embryonic development. In the neural tube, Gli3 transcripts are patterned along the anteroposterior and dorsoventral axes such that the initial broad expression in the posterior neural tube becomes dorsally restricted as neurogenesis takes place. Little is known about the molecular mechanisms that regulate this dynamic expression. Here, we report on a phylogen...
GLI1, a master regulator of the hallmark of pancreatic cancer.

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Kasai, Kenji

2016-12-01

Hedgehog signaling is highly conserved across species and governs proper embryonic development. Germline gene mutations that reduce this signaling activity cause a variety of developmental abnormalities such as holoprosencephaly, while those that enhance Hedgehog signaling activity induce a tumor-predisposition condition Nevoid basal cell carcinoma syndrome. Furthermore, dysregulated activation of Hedgehog signaling has been recognized in various sporadic malignancies, including pancreatic adenocarcinoma. Pancreatic adenocarcinoma develops through a multistep carcinogenesis starting with oncogenic mutation of the KRAS gene. During this process, precancerous or cancer cells secrete Hedgehog ligand proteins to promote characteristic desmoplastic stroma around the cells, which in turn activates the expression of the downstream transcription factor GLI1 inside the cells. The quantitative and spatiotemporal dysregulation of GLI1 subsequently leads to the expression of transcriptional target genes of GLI1 that govern the hallmark of malignant properties. Here, after a brief introductory outline, a perspective is offered of Hedgehog signaling with a special focus on the role of GLI1 in pancreatic carcinogenesis. © 2016 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.
The role of the Hedgehog signaling pathway in cancer: A comprehensive review

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Ana Marija Skoda

2018-02-01

Full Text Available The Hedgehog (Hh signaling pathway was first identified in the common fruit fly. It is a highly conserved evolutionary pathway of signal transmission from the cell membrane to the nucleus. The Hh signaling pathway plays an important role in the embryonic development. It exerts its biological effects through a signaling cascade that culminates in a change of balance between activator and repressor forms of glioma-associated oncogene (Gli transcription factors. The components of the Hh signaling pathway involved in the signaling transfer to the Gli transcription factors include Hedgehog ligands (Sonic Hh [SHh], Indian Hh [IHh], and Desert Hh [DHh], Patched receptor (Ptch1, Ptch2, Smoothened receptor (Smo, Suppressor of fused homolog (Sufu, kinesin protein Kif7, protein kinase A (PKA, and cyclic adenosine monophosphate (cAMP. The activator form of Gli travels to the nucleus and stimulates the transcription of the target genes by binding to their promoters. The main target genes of the Hh signaling pathway are PTCH1, PTCH2, and GLI1. Deregulation of the Hh signaling pathway is associated with developmental anomalies and cancer, including Gorlin syndrome, and sporadic cancers, such as basal cell carcinoma, medulloblastoma, pancreatic, breast, colon, ovarian, and small-cell lung carcinomas. The aberrant activation of the Hh signaling pathway is caused by mutations in the related genes (ligand-independent signaling or by the excessive expression of the Hh signaling molecules (ligand-dependent signaling – autocrine or paracrine. Several Hh signaling pathway inhibitors, such as vismodegib and sonidegib, have been developed for cancer treatment. These drugs are regarded as promising cancer therapies, especially for patients with refractory/advanced cancers.
Lithium Suppresses Hedgehog Signaling via Promoting ITCH E3 Ligase Activity and Gli1–SUFU Interaction in PDA Cells

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Xinshuo Wang

2017-11-01

Full Text Available Dysregulation of Hedgehog (Hh signaling pathway is one of the hallmarks of pancreatic ductal adenocarcinoma (PDA. Lithium, a clinical mood stabilizer for the treatment of mental disorders, is known to suppress tumorigenic potential of PDA cells by targeting the Hh/Gli signaling pathway. In this study, we investigated the molecular mechanism of lithium induced down-regulation of Hh/Gli1. Our data show that lithium promotes the poly-ubiquitination and proteasome-mediated degradation of Gli1 through activating E3 ligase ITCH. Additionally, lithium enhances interaction between Gli1 and SUFU via suppressing GSK3β, which phosphorylates SUFU and destabilizes the SUFU-Gli1 inhibitory complex. Our studies illustrate a novel mechanism by which lithium suppresses Hh signaling via simultaneously promoting ITCH-dependent Gli1 ubiquitination/degradation and SUFU-mediated Gli1 inhibition.
Gli3 Regulation of Myogenesis Is Necessary for Ischemia-Induced Angiogenesis

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Renault, Marie-Ange; Vandierdonck, Soizic; Chapouly, Candice; Yu, Yang; Qin, Gangjian; Metras, Alexandre; Couffinhal, Thierry; Losordo, Douglas W.; Yao, Qinyu; Reynaud, Annabel; Jaspard-Vinassa, Béatrice; Belloc, Isabelle; Desgranges, Claude; Gadeau, Alain-Pierre

2015-01-01

Rationale A better understanding of the mechanism underlying skeletal muscle repair is required to develop therapies that promote tissue regeneration in adults. Hedgehog signaling has been shown previously to be involved in myogenesis and angiogenesis: 2 crucial processes for muscle development and regeneration. Objective The objective of this study was to identify the role of the hedgehog transcription factor Gli3 in the crosstalk between angiogenesis and myogenesis in adults. Methods and Results Using conditional knockout mice, we found that Gli3 deficiency in endothelial cells did not affect ischemic muscle repair, whereas in myocytes, Gli3 deficiency resulted in severely delayed ischemia-induced myogenesis. Moreover, angiogenesis was also significantly impaired in HSA-CreERT2; Gli3Flox/Flox mice, demonstrating that impaired myogenesis indirectly affects ischemia-induced angiogenesis. The role of Gli3 in myocytes was then further investigated. We found that Gli3 promotes myoblast differentiation through myogenic factor 5 regulation. In addition, we found that Gli3 regulates several proangiogenic factors, including thymidine phosphorylase and angiopoietin-1 both in vitro and in vivo, which indirectly promote endothelial cell proliferation and arteriole formation. In addition, we found that Gli3 is upregulated in proliferating myoblasts by the cell cycle–associated transcription factor E2F1. Conclusions This study shows for the first time that Gli3-regulated postnatal myogenesis is necessary for muscle repair–associated angiogenesis. Most importantly, it implies that myogenesis drives angiogenesis in the setting of skeletal muscle repair and identifies Gli3 as a potential target for regenerative medicine. PMID:24044950
The immunoprofile of odontogenic keratocyst (keratocystic odontogenic tumor) that includes expression of PTCH, SMO, GLI-1 and bcl-2 is similar to ameloblastoma but different from odontogenic cysts.

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Vered, M; Peleg, O; Taicher, S; Buchner, A

2009-08-01

The aggressive biological behavior of odontogenic keratocysts (OKCs), unlike that of other odontogenic cysts, has argued for its recent re-classification as a neoplasm, 'keratocystic odontogenic tumor'. Identification of mutations in the PTCH gene in some of the OKCs that were expected to produce truncated proteins, resulting in loss of control of the cell cycle, provided additional support for OKCs having a neoplastic nature. We investigated the immunohistochemical expression of the sonic hedgehog (SHH) signaling pathway-related proteins, PTCH, smoothened (SMO) and GLI-1, and of the SHH-induced bcl-2 oncoprotein in a series of primary OKC (pOKC), recurrent OKC (rOKC) and nevoid basal cell carcinoma syndrome-associated OKCs (NBCCS-OKCs), and compared them to solid ameloblastomas (SAMs), unicystic ameloblastomas (UAMs), 'orthokeratinized' OKCs (oOKCs), dentigerous cysts (DCs) and radicular cysts (RCs). All studied lesions expressed the SHH pathway-related proteins in a similar pattern. The expression of bcl-2 in OKCs (pOKCs and NBCCS-OKCs) and SAMs was significantly higher than in oOKCs, DCs and RCs (P < 0.001). The present results of the immunoprofile of OKCs (that includes the expression of the SHH-related proteins and the SHH-induced bcl-2 oncoprotein) further support the notion of OKC having a neoplastic nature. As OKCs vary considerably in their biologic behavior, it is suggested that the quality and quantity of interactions between the SHH and other cell cycle regulatory pathways are likely to work synergistically to define the individual phenotype and corresponding biological behavior of this lesion.
PTCH1 is a reliable marker for predicting imatinib response in chronic myeloid leukemia patients in chronic phase.

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Juan M Alonso-Dominguez

Full Text Available Patched homolog 1 gene (PTCH1 expression and the ratio of PTCH1 to Smoothened (SMO expression have been proposed as prognostic markers of the response of chronic myeloid leukemia (CML patients to imatinib. We compared these measurements in a realistic cohort of 101 patients with CML in chronic phase (CP using a simplified qPCR method, and confirmed the prognostic power of each in a competing risk analysis. Gene expression levels were measured in peripheral blood samples at diagnosis. The PTCH1/SMO ratio did not improve PTCH1 prognostic power (area under the receiver operating characteristic curve 0.71 vs. 0.72. In order to reduce the number of genes to be analyzed, PTCH1 was the selected measurement. High and low PTCH1 expression groups had significantly different cumulative incidences of imatinib failure (IF, which was defined as discontinuation of imatinib due to lack of efficacy (5% vs. 25% at 4 years, P = 0.013, probabilities of achieving a major molecular response (81% vs. 53% at first year, P = 0.02, and proportions of early molecular failure (14% vs. 43%, P = 0.015. Every progression to an advanced phase (n = 3 and CML-related death (n = 2 occurred in the low PTCH1 group (P<0.001 for both comparisons. PTCH1 was an independent prognostic factor for the prediction of IF. We also validated previously published thresholds for PTCH1 expression. Therefore, we confirmed that PTCH1 expression can predict the imatinib response in CML patients in CP by applying a more rigorous statistical analysis. Thus, PTCH1 expression is a promising molecular marker for predicting the imatinib response in CML patients in CP.
Msx genes are important apoptosis effectors downstream of the Shh/Gli3 pathway in the limb.

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Lallemand, Yvan; Bensoussan, Vardina; Cloment, Cécile Saint; Robert, Benoît

2009-07-15

In tetrapods, the anteroposterior (AP) patterning of the limb is under the control of the antagonistic activities of the secreted factor Sonic hedgehog (Shh) and Gli3R, the truncated repressor form of the transcription factor Gli3. In this report, we show that Msx1 and Msx2 are targets and downstream effectors of Gli3R. Consequently, in Shh null mutants, Msx genes are overexpressed and, furthermore, partially responsible for the limb phenotype. This is exemplified by the fact that reducing Msx activity in Shh mutants partially restores a normal limb development. Finally, we show that the main action of the Msx genes, in both normal and Shh(-/-) limb development, is to control cell death in the mesenchyme. We propose that, in the limb, Msx genes act downstream of the Shh/Gli3 pathway by transducing BMP signaling and that, in the absence of Shh signaling, their deregulation contributes to the extensive apoptosis that impairs limb development.
Identification of RegIV as a novel GLI1 target gene in human pancreatic cancer.

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Feng Wang

2011-04-01

Full Text Available GLI1 is the key transcriptional factor in the Hedgehog signaling pathway in pancreatic cancer. RegIV is associated with regeneration, and cell growth, survival, adhesion and resistance to apoptosis. We aimed to study RegIV expression in pancreatic cancer and its relationship to GLI1.GLI1 and RegIV expression were evaluated in tumor tissue and adjacent normal tissues of pancreatic cancer patients and 5 pancreatic cancer cell lines by qRT-PCR, Western blot, and immunohistochemistry (IHC, and the correlation between them. The GLI1-shRNA lentiviral vector was constructed and transfected into PANC-1, and lentiviral vector containing the GLI1 expression sequence was constructed and transfected into BxPC-3. GLI1 and RegIV expression were evaluated by qRT-PCR and Western blot. Finally we demonstrated RegIV to be the target of GLI1 by chromatin immunoprecipitation (CHIP and electrophoretic mobility shift assays (EMSA.The results of IHC and qRT-PCR showed that RegIV and GLI1 expression was higher in pancreatic cancer tissues versus adjacent normal tissues (p<0.001. RegIV expression correlated with GLI1 expression in these tissues (R = 0.795, p<0.0001. These results were verified for protein (R = 0.939, p = 0.018 and mRNA expression (R = 0.959, p = 0.011 in 5 pancreatic cancer cell lines. RegIV mRNA and protein expression was decreased (94.7±0.3%, 84.1±0.5%; respectively when GLI1 was knocked down (82.1±3.2%, 76.7±2.2%; respectively by the RNAi technique. GLI1 overexpression in mRNA and protein level (924.5±5.3%, 362.1±3.5%; respectively induced RegIV overexpression (729.1±4.3%, 339.0±3.7%; respectively. Moreover, CHIP and EMSA assays showed GLI1 protein bound to RegIV promotor regions (GATCATCCA in pancreatic cancer cells.GLI1 promotes RegIV transcription by binding to the RegIV gene promoter in pancreatic cancer.
A novel PTCH1 mutation in a patient with Gorlin syndrome.

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Okamoto, Nana; Naruto, Takuya; Kohmoto, Tomohiro; Komori, Takahide; Imoto, Issei

2014-01-01

Gorlin syndrome is an autosomal dominant disorder characterized by a wide range of developmental abnormalities and a predisposition to various tumors, and it is linked to the alteration of several causative genes, including PTCH1. We performed targeted resequencing using a next-generation sequencer to analyze genes associated with known clinical phenotypes in an 11-year-old male with sporadic jaw keratocysts. A novel duplication mutation (c.426dup) in PTCH1, resulting in a truncated protein, was identified.

Gorlin syndrome with an ovarian leiomyoma associated with a PTCH1 second hit.

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Akizawa, Yoshika; Miyashita, Toshiyuki; Sasaki, Ryo; Nagata, Reiko; Aoki, Ryoko; Ishitani, Ken; Nagashima, Yoji; Matsui, Hideo; Saito, Kayoko

2016-04-01

We describe a Gorlin syndrome (GS) case with two different second hit mutations of PTCH1, one in a keratocystic odontogenic tumor (KCOT) and the other in an ovarian leiomyoma. GS is a rare genetic condition manifesting as multiple basal cell nevi associated with other features such as medulloblastomas, skeletal abnormalities, and ovarian fibromas. A 21-year-old Japanese woman with a history of two KCOTs was diagnosed with GS according to clinical criteria. A PTCH1 mutation, c.1427del T, was detected in peripheral blood. A novel PTCH1 mutation, c.264_265insAATA, had been found in the maxillary KCOT as a second hit mutation. More recently, the ovarian tumor was detected during a gynecological examination. Laparoscopic adnexectomy was performed, and the pathological diagnosis of the ovarian tumor was leiomyoma. Interestingly, another novel mutation, loss of heterozygosity spanning from 9q22.32 to 9q31.2, including PTCH1 and 89 other genes, was detected in this ovarian tumor, providing evidence of a second hit mutation. This is the first report describing a GS-associated ovarian tumor carrying a second hit in the PTCH1 region. We anticipate that accumulation of more cases will clarify the importance of second hit mutations in ovarian tumor formation in GS. © 2016 Wiley Periodicals, Inc.
Radiation-induced chemical evolution of glycine to (Gly)2, (Gly)3, and (Gly)4

International Nuclear Information System (INIS)

Matsui, T.; Izumi, Y.; Kamohara, M.; Nakagawa, K.; Yokoya, A.

2006-01-01

Recently amino acids were detected from some meteorites. Since these amino acids were found after hydrolysis, some oligopeptides were possibly formed in space. A simulation experiment of chemical evolution from Glycine (Gly) to Glycylglycine ((Gly)2) was reported by Kaneko et al. In this work, we irradiated (Gly)2 with 8 eV vacuum ultraviolet photons or with 530 eV soft X-ray photons and examined absolute values of quantum yield of radiation-induced chemical evolution from Gly2 to Glycylglycylglycine ((Gly)3) and Glycylglycylglycylglycine ((Gly)4). Thin films of (Gly)2 were prepared on quartz plate or CuBe plate with a vacuum evaporation technique. These samples were irradiated by 8 eV photons from a Xe 2 * excimer lamp or by 530 eV soft X-ray photons at SPring-8 Synchrotron Radiation Facility. Irradiated samples were analyzed with a high performance liquid chromatography HPLC. Decomposition of (Gly)2 and production of Gly, (Gly)3 and (Gly)4 were observed. Quantum yield Y was defined to be N = Y N 0 , where N is the number of produced or decomposed molecule, and N 0 is the number of (Gly)2 molecules excited by photons. Obtained results by 8 eV irradiation were summarized in Table 1. The similar magnitude of decomposition of (Gly)2 may show that yield of the primary breaking reaction upon photo-excitation is of similar magnitude. It should be noted that (Gly)3 and (Gly)4 was produced by irradiation with the yield of 10 -4 without any catalysis. For soft X-ray irradiation, yield of Gly was tentatively determined to be about 40. This largervalue than that for 8 eV irradiation may originate from large energy of incident soft X-ray photons just like a result reported by Simakov et al. We will discuss in detail at the conference. (authors)
Inhibition of p70S6K2 down-regulates Hedgehog/GLI pathway in non-small cell lung cancer cell lines

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Kotani Hidehito

2009-07-01

Full Text Available Abstract Background The Hedgehog (HH pathway promotes tumorigenesis in a diversity of cancers. Activation of the HH signaling pathway is caused by overexpression of HH ligands or mutations in the components of the HH/GLI1 cascade, which lead to increased transactivation of GLI transcription factors. Although negative kinase regulators that antagonize the activity of GLI transcription factors have been reported, including GSK3β, PKA and CK1s, little is known regarding positive kinase regulators that are suitable for use on cancer therapeutic targets. The present study attempted to identify kinases whose silencing inhibits HH/GLI signalling in non-small cell lung cancer (NSCLC. Results To find positive kinase regulators in the HH pathway, kinome-wide siRNA screening was performed in a NSCLC cell line, A549, harboring the GLI regulatory reporter gene. This showed that p70S6K2-silencing remarkably reduced GLI reporter gene activity. The decrease in the activity of the HH pathway caused by p70S6K2-inhibition was accompanied by significant reduction in cell viability. We next investigated the mechanism for p70S6K2-mediated inhibition of GLI1 transcription by hypothesizing that GSK3β, a negative regulator of the HH pathway, is activated upon p70S6K2-silencing. We found that phosphorylated-GSK3β (Ser9 was reduced by p70S6K2-silencing, causing a decreased level of GLI1 protein. Finally, to further confirm the involvement of p70S6K2 in GLI1 signaling, down-regulation in GLI-mediated transcription by PI3KCA-inhibition was confirmed, establishing the pivotal role of the PI3K/p70S6K2 pathway in GLI1 cascade regulation. Conclusion We report herein that inhibition of p70S6K2, known as a downstream effector of the PI3K pathway, remarkably decreases GLI-mediated transactivation in NSCLC by reducing phosphorylated-GSK3β followed by GLI1 degradation. These results infer that p70S6K2 is a potential therapeutic target for NSCLC with hyperactivated HH/GLI pathway.
Activity of Metabotropic Glutamate Receptor 4 Suppresses Proliferation and Promotes Apoptosis With Inhibition of Gli-1 in Human Glioblastoma Cells

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Zhichao Zhang

2018-05-01

Full Text Available Glioblastoma multiforme (GBM is the most lethal glioma variant in the adult brain and among the deadliest of human cancers. Increasing evidence has shown that metabotropic glutamate receptor subtype 4 (mGluR4 expression may play roles in regulating the growth of neural stem cells as well as several cancer cell lines. Here, we investigated the effects of mGluR4 on the growth and apoptosis of the LN229 GBM cell line. Involvement of Gli-1, one of the key transcription factors in the sonic Hedgehog (SHH signaling pathway, was further explored. In this study, mGluR4 was activated using selective agonist VU0155041; and gene-targeted siRNAs were used to generate loss of function of mGluR4 and Gli-1 in LN229 cells. The results demonstrated that LN229 cells expressed mGluR4 and the agonist VU0155041 decreased cell viability in a dose- and time-dependent manner. Activation of mGluR4 inhibited cyclin D1 expression, activated pro-caspase-8/9/3, and disrupted the balance of Bcl-2/Bax expression, which indicated cell cycle arrest and apoptosis of LN229 cells, respectively. Furthermore, Gli-1 expression was reduced by mGluR4 activation in LN229 cells, and downregulation of Gli-1 expression by gene-targeted siRNA resulted in both inhibition of cell proliferation and promotion of apoptosis. Moreover, VU0155041 treatment substantially blocked SHH-induced cyclin D1 expression and cell proliferation, while increasing TUNEL-positive cells and the activation of apoptosis-related proteins. We concluded that activation of mGluR4 expressed in LN229 cells could inhibit GBM cell growth by decreasing cell proliferation and promoting apoptosis. Further suppression of intracellular Gli-1 expression might be involved in the action of mGluR4 on cancer cells. Our study suggested a novel role of mGluR4, which might serve as a potential drug target for control of GBM cell growth.
GLI1 interferes with the DNA mismatch repair system in pancreatic cancer through BHLHE41-mediated suppression of MLH1.

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Inaguma, Shingo; Riku, Miho; Hashimoto, Mitsuyoshi; Murakami, Hideki; Saga, Shinsuke; Ikeda, Hiroshi; Kasai, Kenji

2013-12-15

The mismatch repair (MMR) system is indispensable for the fidelity of DNA replication, the impairment of which predisposes to the development and progression of many types of cancers. To date, GLI1 transcription factor, a key molecule of the Hedgehog signaling pathway, has been shown to regulate the expression of several genes crucial for a variety of cancer cell properties in many types of cancers, including pancreatic ductal adenocarcinoma (PDAC), but whether GLI1 could control the MMR system was not known. Here, we showed that GLI1 and GLI2 indirectly suppressed the expression of MLH1 in PDAC cells. Through GLI1 target gene screening, we found that GLI1 and GLI2 activated the expression of a basic helix-loop-helix type suppressor BHLHE41/DEC2/SHARP1 through a GLI-binding site in the promoter. Consistent with a previous report that BHLHE41 suppresses the MLH1 promoter activity, we found that the activation of GLI1 led to the BHLHE41-dependent suppression of MLH1, and a double knockdown of GLI1 and GLI2 conversely increased the MLH1 protein in PDAC cells. Using TALEN-based modification of the MLH1 gene, we further showed that GLI1 expression was indeed associated with an increased tolerance to a methylating agent, methylnitrosourea cooperatively with a lower copy number status of MLH1. Finally, GLI1 expression was immunohistochemically related positively with BHLHE41 and inversely with MLH1 in PDAC cells and precancerous lesions of the pancreas. On the basis of these results, we propose that GLI1 depresses the MMR activity and might contribute to the development and progression of PDAC. ©2013 AACR.
Ihh controls cartilage development by antagonizing Gli3, but requires additional effectors to regulate osteoblast and vascular development.

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Hilton, Matthew J; Tu, Xiaolin; Cook, Julie; Hu, Hongliang; Long, Fanxin

2005-10-01

Indian hedgehog (Ihh) controls multiple aspects of endochondral skeletal development, including proliferation and maturation of chondrocytes, osteoblast development and cartilage vascularization. Although it is known that Gli transcription factors are key effectors of hedgehog signaling, it has not been established which Gli protein mediates Ihh activity in skeletal development. Here, we show that removal of Gli3 in Ihh-null mouse embryos restored normal proliferation and maturation of chondrocytes, but only partially rescued the defects in osteoblast development and cartilage vascularization. Remarkably, in both Ihh-/- and Ihh-/-; Gli3-/- embryos, vascularization promoted osteoblast development in perichondrial progenitor cells. Our results not only establish Gli3 as a critical effector for Ihh activity in the developing skeleton, but also identify an osteogenic role for a vasculature-derived signal, which integrates with Ihh and Wnt signals to determine the osteoblast versus chondrocyte fate in the mesenchymal progenitors.
Missense mutations in IHH impair Indian Hedgehog signaling in C3H10T1/2 cells: Implications for brachydactyly type A1, and new targets for Hedgehog signaling.

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Guo, Shengzhen; Zhou, Jian; Gao, Bo; Hu, Jianxin; Wang, Hongsheng; Meng, Junwei; Zhao, Xinzhi; Ma, Gang; Lin, Chuwen; Xiao, Yue; Tang, Wei; Zhu, Xuming; Cheah, Kathryn S E; Feng, Guoying; Chan, Danny; He, Lin

2010-01-01

Heterozygous missense mutations in IHH result in Brachydactyly type A1 (BDA1; OMIM 112500), a condition characterized by the shortening of digits due to hypoplasia/aplasia of the middle phalanx. Indian Hedgehog signaling regulates the proliferation and differentiation of chondrocytes and is essential for endochondral bone formation. Analyses of activated IHH signaling in C3H10T1/2 cells showed that three BDA1-associated mutations (p.E95K, p.D100E and p.E131K) severely impaired the induction of targets such as Ptch1 and Gli1. However, this was not a complete loss of function, suggesting that these mutations may affect the interaction with the receptor PTCH1 or its partners, with an impact on the induction potency. From comparative microarray expression analyses and quantitative real-time PCR, we identified three additional targets, Sostdc1, Penk1 and Igfbp5, which were also severely affected. Penk1 and Igfbp5 were confirmed to be regulated by GLI1, while the induction of Sostdc1 by IHH is independent of GLI1. SOSTDC1 is a BMP antagonist, and altered BMP signaling is known to affect digit formation. The role of Penk1 and Igfbp5 in skeletogenesis is not known. However, we have shown that both Penk1 and Igfbp5 are expressed in the interzone region of the developing joint of mouse digits, providing another link for a role for IHH signaling in the formation of the distal digits.
Histone acetyltransferase PCAF is required for Hedgehog-Gli-dependent transcription and cancer cell proliferation

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Malatesta, Martina; Steinhauer, Cornelia; Mohammad, Faizaan

2013-01-01

The Hedgehog (Hh) signaling pathway plays an important role in embryonic patterning and development of many tissues and organs as well as in maintaining and repairing mature tissues in adults. Uncontrolled activation of the Hh-Gli pathway has been implicated in developmental abnormalities as well...... that the histone acetyltransferase PCAF/KAT2B is an important factor of the Hh pathway. Specifically, we show that PCAF depletion impairs Hh activity and reduces expression of Hh target genes. Consequently, PCAF downregulation in medulloblastoma and glioblastoma cells leads to decreased proliferation and increased...... apoptosis. In addition, we found that PCAF interacts with GLI1, the downstream effector in the Hh-Gli pathway, and that PCAF or GLI1 loss reduces the levels of H3K9 acetylation on Hh target gene promoters. Finally, we observed that PCAF silencing reduces the tumor-forming potential of neural stem cells...
Nos2 inactivation promotes the development of medulloblastoma in Ptch1(+/- mice by deregulation of Gap43-dependent granule cell precursor migration.

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Daniel Haag

Full Text Available Medulloblastoma is the most common malignant brain tumor in children. A subset of medulloblastoma originates from granule cell precursors (GCPs of the developing cerebellum and demonstrates aberrant hedgehog signaling, typically due to inactivating mutations in the receptor PTCH1, a pathomechanism recapitulated in Ptch1(+/- mice. As nitric oxide may regulate GCP proliferation and differentiation, we crossed Ptch1(+/- mice with mice lacking inducible nitric oxide synthase (Nos2 to investigate a possible influence on tumorigenesis. We observed a two-fold higher medulloblastoma rate in Ptch1(+/- Nos2(-/- mice compared to Ptch1(+/- Nos2(+/+ mice. To identify the molecular mechanisms underlying this finding, we performed gene expression profiling of medulloblastomas from both genotypes, as well as normal cerebellar tissue samples of different developmental stages and genotypes. Downregulation of hedgehog target genes was observed in postnatal cerebellum from Ptch1(+/+ Nos2(-/- mice but not from Ptch1(+/- Nos2(-/- mice. The most consistent effect of Nos2 deficiency was downregulation of growth-associated protein 43 (Gap43. Functional studies in neuronal progenitor cells demonstrated nitric oxide dependence of Gap43 expression and impaired migration upon Gap43 knock-down. Both effects were confirmed in situ by immunofluorescence analyses on tissue sections of the developing cerebellum. Finally, the number of proliferating GCPs at the cerebellar periphery was decreased in Ptch1(+/+ Nos2(-/- mice but increased in Ptch1(+/- Nos2(-/ (- mice relative to Ptch1(+/- Nos2(+/+ mice. Taken together, these results indicate that Nos2 deficiency promotes medulloblastoma development in Ptch1(+/- mice through retention of proliferating GCPs in the external granular layer due to reduced Gap43 expression. This study illustrates a new role of nitric oxide signaling in cerebellar development and demonstrates that the localization of pre-neoplastic cells during
Evolution and Functional Diversification of the GLI Family of Transcription Factors in Vertebrates

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Amir Ali Abbasi

2009-05-01

Full Text Available Background: In vertebrates the “SONIC HEDGEHOG” signalling pathway has been implicated in cell-fate determination, proliferation and the patterning of many different cell types and organs. As the GLI family members (GLI1, GLI2 and GLI3 are key mediators of hedgehog morphogenetic signals, over the past couple of decades they have been extensively scrutinized by genetic, molecular and biochemical means. Thus, a great deal of information is currently available about the functional aspects of GLI proteins in various vertebrate species. To address the roles of GLI genes in diversifying the repertoire of the Hh signalling and deploying them for the vertebrate specifications, in this study we have examined the evolutionary patterns of vertebrate GLI sequences within and between species. Results: Phylogenetic tree analysis suggests that the vertebrate GLI1, GLI2 and GLI3 genes diverged after the separation of urochordates from vertebrates and before the tetrapods-bony fishes split. Lineage specific duplication events were also detected. Estimation of mode and strength of selection acting on GLI orthologs demonstrated that all members of the GLI gene family experienced more relaxed selection in teleost fish than in the mammalian lineage. Furthermore, the GLI1 gene appeared to have been exposed to different functional constraints in fish and tetrapod lineages, whilst a similar level of functional constraints on GLI2 and GLI3 was suggested by comparable average non-synonymous (Ka substitutions across the lineages. A relative rate test suggested that the majority of the paralogous copies of the GLI family analyzed evolved with similar evolutionary rates except GLI1 which evolved at a significantly faster rate than its paralogous counterparts in tetrapods. Conclusions: Our analysis shows that sequence evolutionary patterns of GLI family members are largely correlated with the reported similarities and differences in the functionality of GLI proteins
Hedgehog signaling pathway in neuroblastoma differentiation.

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Souzaki, Ryota; Tajiri, Tatsuro; Souzaki, Masae; Kinoshita, Yoshiaki; Tanaka, Sakura; Kohashi, Kenichi; Oda, Yoshinao; Katano, Mitsuo; Taguchi, Tomoaki

2010-12-01

The hedgehog (Hh) signaling pathway is activated in some adult cancers. On the other hand, the Hh signaling pathway plays an important role in the development of the neural crest in embryos. The aim of this study is to show the activation of Hh signaling pathway in neuroblastoma (NB), a pediatric malignancy arising from neural crest cells, and to reveal the meaning of the Hh signaling pathway in NB development. This study analyzed the expression of Sonic hedgehog (Shh), GLI1, and Patched 1 (Ptch1), transactivators of Hh signaling pathway, by immunohistochemistry in 82 NB and 10 ganglioneuroblastoma cases. All 92 cases were evaluated for the status of MYCN amplification. Of the 92 cases, 67 (73%) were positive for Shh, 62 cases (67%) were positive for GLI1, and 73 cases (79%) were positive for Ptch1. Only 2 (10%) of the 20 cases with MYCN amplification were positive for Shh and GLI1, and 4 cases (20%) were positive for Ptch1 (MYCN amplification vs no MYCN amplification, P ≦ .01). The percentage of GLI1-positive cells in the cases with INSS stage 1 without MYCN amplification was significantly higher than that with INSS stage 4. Of 72 cases without MYCN amplification, 60 were GLI1-positive. Twelve cases were GLI1-negative, and the prognosis of the GLI1-positive cases was significantly better than that of the GLI1-negative cases (P = .015). Most of NBs without MYCN amplification were positive for Shh, GLI1, and Ptch1. In the cases without MYCN amplification, the high expression of GLI1 was significantly associated with early clinical stage and a good prognosis of the patients. In contrast to adult cancers, the activation of the Hh signaling pathway in NB may be associated with the differentiation of the NB. Copyright © 2010 Elsevier Inc. All rights reserved.
GLI1 is a central mediator of EWS/FLI1 signaling in Ewing tumors.

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Jay Joo

2009-10-01

Full Text Available The Ewing Sarcoma Family Tumors (ESFT consist of the classical pathologic entities of Ewing Sarcoma and peripheral Primitive Neuroectodermal Tumor. Occurring largely in the childhood through young adult years, these tumors have an unsurpassed propensity for metastasis and have no defined cell of origin. The biology of these aggressive malignancies centers around EWS/FLI1 and related EWS/ETS chimeric transcription factors, which are largely limited to this tumor class. Much progress has been made in the identification of a network of loci whose expression is modulated by EWS/FLI1 and its congeners. To date, little progress has been made in reconstructing the sequence of direct and indirect events that produce this network of modulated loci. The recent identification of GLI1 as an upregulated target of EWS/ETS transcription factors suggests a target which may be a more central mediator in the ESFT signaling network. In this paper, we further define the relationship of EWS/FLI1 expression and GLI1 upregulation in ESFT. This relationship is supported with data from primary tumor specimens. It is consistently observed across multiple ESFT cell lines and with multiple means of EWS/FLI1 inhibition. GLI1 inhibition affects tumor cell line phenotype whether shRNA or endogenous or pharmacologic inhibitors are employed. As is seen in model transformation systems, GLI1 upregulation by EWS/FLI1 appears to be independent of Hedgehog stimulation. Consistent with a more central role in ESFT pathogenesis, several known EWS/FLI1 targets appear to be targeted through GLI1. These findings further establish a central role for GLI1 in the pathogenesis of Ewing Tumors.
A genome scale RNAi screen identifies GLI1 as a novel gene regulating vorinostat sensitivity.

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Falkenberg, K J; Newbold, A; Gould, C M; Luu, J; Trapani, J A; Matthews, G M; Simpson, K J; Johnstone, R W

2016-07-01

Vorinostat is an FDA-approved histone deacetylase inhibitor (HDACi) that has proven clinical success in some patients; however, it remains unclear why certain patients remain unresponsive to this agent and other HDACis. Constitutive STAT (signal transducer and activator of transcription) activation, overexpression of prosurvival Bcl-2 proteins and loss of HR23B have been identified as potential biomarkers of HDACi resistance; however, none have yet been used to aid the clinical utility of HDACi. Herein, we aimed to further elucidate vorinostat-resistance mechanisms through a functional genomics screen to identify novel genes that when knocked down by RNA interference (RNAi) sensitized cells to vorinostat-induced apoptosis. A synthetic lethal functional screen using a whole-genome protein-coding RNAi library was used to identify genes that when knocked down cooperated with vorinostat to induce tumor cell apoptosis in otherwise resistant cells. Through iterative screening, we identified 10 vorinostat-resistance candidate genes that sensitized specifically to vorinostat. One of these vorinostat-resistance genes was GLI1, an oncogene not previously known to regulate the activity of HDACi. Treatment of vorinostat-resistant cells with the GLI1 small-molecule inhibitor, GANT61, phenocopied the effect of GLI1 knockdown. The mechanism by which GLI1 loss of function sensitized tumor cells to vorinostat-induced apoptosis is at least in part through interactions with vorinostat to alter gene expression in a manner that favored apoptosis. Upon GLI1 knockdown and vorinostat treatment, BCL2L1 expression was repressed and overexpression of BCL2L1 inhibited GLI1-knockdown-mediated vorinostat sensitization. Taken together, we present the identification and characterization of GLI1 as a new HDACi resistance gene, providing a strong rationale for development of GLI1 inhibitors for clinical use in combination with HDACi therapy.
Pre-synaptic glycine GlyT1 transporter--NMDA receptor interaction: relevance to NMDA autoreceptor activation in the presence of Mg2+ ions.

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Musante, Veronica; Summa, Maria; Cunha, Rodrigo A; Raiteri, Maurizio; Pittaluga, Anna

2011-05-01

Rat hippocampal glutamatergic terminals possess NMDA autoreceptors whose activation by low micromolar NMDA elicits glutamate exocytosis in the presence of physiological Mg(2+) (1.2 mM), the release of glutamate being significantly reduced when compared to that in Mg(2+)-free condition. Both glutamate and glycine were required to evoke glutamate exocytosis in 1.2 mM Mg(2+), while dizocilpine, cis-4-[phosphomethyl]-piperidine-2-carboxylic acid and 7-Cl-kynurenic acid prevented it, indicating that occupation of both agonist sites is needed for receptor activation. D-serine mimicked glycine but also inhibited the NMDA/glycine-induced release of [(3H]D-aspartate, thus behaving as a partial agonist. The NMDA/glycine-induced release in 1.2 mM Mg(2+) strictly depended on glycine uptake through the glycine transporter type 1 (GlyT1), because the GlyT1 blocker N-[3-(4'-fluorophenyl)-3-(4'-phenylphenoxy)propyl])sarcosine hydrochloride, but not the GlyT2 blocker Org 25534, prevented it. Accordingly, [(3)H]glycine was taken up during superfusion, while lowering the external concentration of Na(+), the monovalent cation co-transported with glycine by GlyT1, abrogated the NMDA-induced effect. Western blot analysis of subsynaptic fractions confirms that GlyT1 and NMDA autoreceptors co-localize at the pre-synaptic level, where GluN3A subunits immunoreactivity was also recovered. It is proposed that GlyT1s coexist with NMDA autoreceptors on rat hippocampal glutamatergic terminals and that glycine taken up by GlyT1 may permit physiological activation of NMDA pre-synaptic autoreceptors. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.
Expression of the glioma-associated oncogene homolog 1 (gli1 in advanced serous ovarian cancer is associated with unfavorable overall survival.

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Alessandra Ciucci

Full Text Available Recent evidence links aberrant activation of Hedgehog (Hh signaling with the pathogenesis of several cancers including medulloblastoma, glioblastoma, melanoma as well as pancreas, colorectal, and prostate carcinomas. Here we investigated the role of the transcription factor Gli1 in ovarian cancer. To this end, the expression profile of Gli1 was examined in normal ovaries, ovarian tumors, and ovarian cancer cell lines, and the in vitro effects of a specific Hh-pathway blocker, KAAD-cyclopamine, or a specific Gli1 inhibitor (GANT58 on cell proliferation and on Hh target gene expression were also assessed. Results obtained showed that epithelial cells in ovarian cancer tissue express significantly higher levels of nuclear Gli1 than in normal ovarian tissue, where the protein was almost undetectable. In addition, multivariate analysis showed that nuclear Gli1 was independently associated to poor survival in advanced serous ovarian cancer patients (HR = 2.2, 95%CI 1.0-5.1, p = 0.04. In vitro experiments demonstrated Gli1 expression in the three ovarian carcinoma cell lines tested, A2780, SKOV-3 and OVCAR-3. Remarkably, although KAAD-cyclopamine led to decreased cell proliferation, this treatment did not inhibit hedgehog target gene expression in any of the three ovarian cancer cell lines, suggesting that the inhibition of cell proliferation was a nonspecific or toxic effect. In line with these data, no differences on cell proliferation were observed when cell lines were treated with GANT58. Overall, our clinical data support the role of Gli1 as a prognostic marker in advanced serous ovarian cancer and as a possible therapeutic target in this disease. However, our in vitro findings draw attention to the need for selection of appropriate experimental models that accurately represent human tumor for testing future therapies involving Hh pathway inhibitors.
Penetrance of eye defects in mice heterozygous for mutation of Gli3 is enhanced by heterozygous mutation of Pax6

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Price David J

2006-10-01

Full Text Available Abstract Background Knowledge of the consequences of heterozygous mutations of developmentally important genes is important for understanding human genetic disorders. The Gli3 gene encodes a zinc finger transcription factor and homozygous loss-of-function mutations of Gli3 are lethal. Humans heterozygous for mutations in this gene suffer Greig cephalopolysyndactyly or Pallister-Hall syndromes, in which limb defects are prominent, and mice heterozygous for similar mutations have extra digits. Here we examined whether eye development, which is abnormal in mice lacking functional Gli3, is defective in Gli3+/- mice. Results We showed that Gli3 is expressed in the developing eye but that Gli3+/- mice have only very subtle eye defects. We then generated mice compound heterozygous for mutations in both Gli3 and Pax6, which encodes another developmentally important transcription factor known to be crucial for eye development. Pax6+/-; Gli3+/- eyes were compared to the eyes of wild-type, Pax6+/- or Gli3+/- siblings. They exhibited a range of abnormalities of the retina, iris, lens and cornea that was more extensive than in single Gli3+/- or Pax6+/- mutants or than would be predicted by addition of their phenotypes. Conclusion These findings indicate that heterozygous mutations of Gli3 can impact on eye development. The importance of a normal Gli3 gene dosage becomes greater in the absence of a normal Pax6 gene dosage, suggesting that the two genes co-operate during eye morphogenesis.
Ihh/Gli2 signaling promotes osteoblast differentiation by regulating Runx2 expression and function.

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Shimoyama, Atsuko; Wada, Masahiro; Ikeda, Fumiyo; Hata, Kenji; Matsubara, Takuma; Nifuji, Akira; Noda, Masaki; Amano, Katsuhiko; Yamaguchi, Akira; Nishimura, Riko; Yoneda, Toshiyuki

2007-07-01

Genetic and cell biological studies have indicated that Indian hedgehog (Ihh) plays an important role in bone development and osteoblast differentiation. However, the molecular mechanism by which Ihh regulates osteoblast differentiation is complex and remains to be fully elucidated. In this study, we investigated the role of Ihh signaling in osteoblast differentiation using mesenchymal cells and primary osteoblasts. We observed that Ihh stimulated alkaline phosphatase (ALP) activity, osteocalcin expression, and calcification. Overexpression of Gli2- but not Gli3-induced ALP, osteocalcin expression, and calcification of these cells. In contrast, dominant-negative Gli2 markedly inhibited Ihh-dependent osteoblast differentiation. Ihh treatment or Gli2 overexpression also up-regulated the expression of Runx2, an essential transcription factor for osteoblastogenesis, and enhanced the transcriptional activity and osteogenic action of Runx2. Coimmunoprecipitation analysis demonstrated a physical interaction between Gli2 and Runx2. Moreover, Ihh or Gli2 overexpression failed to increase ALP activity in Runx2-deficient mesenchymal cells. Collectively, these results suggest that Ihh regulates osteoblast differentiation of mesenchymal cells through up-regulation of the expression and function of Runx2 by Gli2.
Cyclin D3 interacts with human activating transcription factor 5 and potentiates its transcription activity

International Nuclear Information System (INIS)

Liu Wenjin; Sun Maoyun; Jiang Jianhai; Shen Xiaoyun; Sun Qing; Liu Weicheng; Shen Hailian; Gu Jianxin

2004-01-01

The Cyclin D3 protein is a member of the D-type cyclins. Besides serving as cell cycle regulators, D-type cyclins have been reported to be able to interact with several transcription factors and modulate their transcriptional activations. Here we report that human activating transcription factor 5 (hATF5) is a new interacting partner of Cyclin D3. The interaction was confirmed by in vivo coimmunoprecipitation and in vitro binding analysis. Neither interaction between Cyclin D1 and hATF5 nor interaction between Cyclin D2 and hATF5 was observed. Confocal microscopy analysis showed that Cyclin D3 could colocalize with hATF5 in the nuclear region. Cyclin D3 could potentiate hATF5 transcriptional activity independently of its Cdk4 partner. But Cyclin D1 and Cyclin D2 had no effect on hATF5 transcriptional activity. These data provide a new clue to understand the new role of Cyclin D3 as a transcriptional regulator
Spop promotes skeletal development and homeostasis by positively regulating Ihh signaling.

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Cai, Hongchen; Liu, Aimin

2016-12-20

Indian Hedgehog (Ihh) regulates chondrocyte and osteoblast differentiation through the Glioma-associated oncogene homolog (Gli) transcription factors. Previous in vitro studies suggested that Speckle-type POZ protein (Spop), part of the Cullin-3 (Cul3) ubiquitin ligase complex, targets Gli2 and Gli3 for degradation and negatively regulates Hedgehog (Hh) signaling. In this study, we found defects in chondrocyte and osteoblast differentiation in Spop-null mutant mice. Strikingly, both the full-length and repressor forms of Gli3, but not Gli2, were up-regulated in Spop mutants, and Ihh target genes Patched 1 (Ptch1) and parathyroid hormone-like peptide (Pthlh) were down-regulated, indicating compromised Hh signaling. Consistent with this finding, reducing Gli3 dosage greatly rescued the Spop mutant skeletal defects. We further show that Spop directly targets the Gli3 repressor for ubiquitination and degradation. Finally, we demonstrate in a conditional mutant that loss of Spop results in brachydactyly and osteopenia, which can be rescued by reducing the dosage of Gli3. In summary, Spop is an important positive regulator of Ihh signaling and skeletal development.
Potential hot spot for de novo mutations in PTCH1 gene in Gorlin syndrome patients: a case report of twins from Croatia.

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Musani, Vesna; Ozretić, Petar; Trnski, Diana; Sabol, Maja; Poduje, Sanja; Tošić, Mateja; Šitum, Mirna; Levanat, Sonja

2018-02-28

We describe a case of twins with sporadic Gorlin syndrome. Both twins had common Gorlin syndrome features including calcification of the falx cerebri, multiple jaw keratocysts, and multiple basal cell carcinomas, but with different expressivity. One brother also had benign testicular mesothelioma. We propose this tumor type as a possible new feature of Gorlin syndrome. Gorlin syndrome is a rare autosomal dominant disorder characterized by both developmental abnormalities and cancer predisposition, with variable expression of various developmental abnormalities and different types of tumors. The syndrome is primarily caused by mutations in the Patched 1 (PTCH1) gene, although rare mutations of Patched 2 (PTCH2) or Suppressor of Fused (SUFU) genes have also been found. Neither founder mutations nor hot spot locations have been described for PTCH1 in Gorlin syndrome patients. Although de novo mutations of the PTCH1 gene occur in almost 50% of Gorlin syndrome cases, there are a few recurrent mutations. Our twin patients were carriers of a de novo mutation in the PTCH1 gene, c.3364_3365delAT (p.Met1122ValfsX22). This is, to our knowledge, the first Gorlin syndrome-causing mutation that has been reported four independent times in distant geographical locations. Therefore, we propose the location of the described mutation as a potential hot spot for mutations in PTCH1.

Melittin induces PTCH1 expression by down-regulating MeCP2 in human hepatocellular carcinoma SMMC-7721 cells

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Wu, Xiaoqin; Zhao, Bin; Cheng, Yahui; Yang, Yang; Huang, Cheng; Meng, Xiaoming; Wu, Baoming; Zhang, Lei; Lv, Xiongwen; Li, Jun

2015-01-01

Hepatocellular carcinoma (HCC) has a high mortality rate worldwide and still remains to be a noticeable public health problem. Therefore, new remedies are urgently needed. Melittin, a major component of bee venom, is known to suppress cell growth in various cancers including HCC. However, the mechanism of the anticancer effect of melittin on HCC has not been fully elucidated. It has been reported that Methyl-CpG binding protein 2 (MeCP2) plays a key role in tumor proliferation, apoptosis, migration and invasion. In the present study, we found the high expression of MeCP2 in human HCC tissues and in the SMMC-7721 cell line. MeCP2 silencing inhibited cell proliferation, while over-expression of MeCP2 promoted cell growth in SMMC-7721 cells. It indicates that MeCP2 may be an attractive target for human HCC. We further found that melittin could inhibit cell proliferation by reducing MeCP2 expression in vitro. Interestingly, the inhibitory effect of melittin on cell proliferation was due to a delay in G 0 /G 1 cell cycle progression, without influencing cell apoptosis. Next, we investigated the potential molecular mechanisms and found that MeCP2 could modulate Shh signaling in SMMC-7721 cells. Further study indicates that melittin may induce the demethylation of PTCH1 promoter, resulting in the increased expression of PTCH1. Furthermore, the expression of Shh and GLI1 was significantly lowered upon treatment of melittin. These results suggest that melittin can block Shh signaling in vitro. In short, these results indicate that melittin inhibits cell proliferation by down-regulating MeCP2 through Shh signaling in SMMC-7721 cells. - Highlights: • MeCP2 plays a key role in the proliferation of human HCC cells. • Melittin reduces MeCP2 expression in vitro. • Melittin induces G 0 /G 1 cell cycle arrest in SMMC-7721 cells. • MeCP2 modulates the Shh signaling pathway in SMMC-7721 cells. • Melittin blocks the Shh signaling pathway in SMMC-7721 cells.
Loss-of-Function of Gli3 in Mice Causes Abnormal Frontal Bone Morphology and Premature Synostosis of the Interfrontal Suture

OpenAIRE

Veistinen, Lotta; Takatalo, Maarit; Tanimoto, Yukiho; Kesper, Dörthe A.; Vortkamp, Andrea; Rice, David P. C.

2012-01-01

Greig cephalopolysyndactyly syndrome (GCPS) is an autosomal dominant disorder with polydactyly and syndactyly of the limbs and a broad spectrum of craniofacial abnormalities. Craniosynostosis of the metopic suture (interfrontal suture in mice) is an important but rare feature associated with GCPS. GCPS is caused by mutations in the transcription factor GLI3, which regulates Hedgehog signaling. The Gli3 loss-of-function (Gli3Xt-J/Xt-J) mouse largely phenocopies the human syndrome with the mice...
A mechanism for vertebrate Hedgehog signaling: recruitment to cilia and dissociation of SuFu-Gli protein complexes.

Science.gov (United States)

Tukachinsky, Hanna; Lopez, Lyle V; Salic, Adrian

2010-10-18

In vertebrates, Hedgehog (Hh) signaling initiated in primary cilia activates the membrane protein Smoothened (Smo) and leads to activation of Gli proteins, the transcriptional effectors of the pathway. In the absence of signaling, Gli proteins are inhibited by the cytoplasmic protein Suppressor of Fused (SuFu). It is unclear how Hh activates Gli and whether it directly regulates SuFu. We find that Hh stimulation quickly recruits endogenous SuFu-Gli complexes to cilia, suggesting a model in which Smo activates Gli by relieving inhibition by SuFu. In support of this model, we find that Hh causes rapid dissociation of the SuFu-Gli complex, thus allowing Gli to enter the nucleus and activate transcription. Activation of protein kinase A (PKA), an inhibitor of Hh signaling, blocks ciliary localization of SuFu-Gli complexes, which in turn prevents their dissociation by signaling. Our results support a simple mechanism in which Hh signals at vertebrate cilia cause dissociation of inactive SuFu-Gli complexes, a process inhibited by PKA.
A mechanism for vertebrate Hedgehog signaling: recruitment to cilia and dissociation of SuFu–Gli protein complexes

Science.gov (United States)

Tukachinsky, Hanna; Lopez, Lyle V.

2010-01-01

In vertebrates, Hedgehog (Hh) signaling initiated in primary cilia activates the membrane protein Smoothened (Smo) and leads to activation of Gli proteins, the transcriptional effectors of the pathway. In the absence of signaling, Gli proteins are inhibited by the cytoplasmic protein Suppressor of Fused (SuFu). It is unclear how Hh activates Gli and whether it directly regulates SuFu. We find that Hh stimulation quickly recruits endogenous SuFu–Gli complexes to cilia, suggesting a model in which Smo activates Gli by relieving inhibition by SuFu. In support of this model, we find that Hh causes rapid dissociation of the SuFu–Gli complex, thus allowing Gli to enter the nucleus and activate transcription. Activation of protein kinase A (PKA), an inhibitor of Hh signaling, blocks ciliary localization of SuFu–Gli complexes, which in turn prevents their dissociation by signaling. Our results support a simple mechanism in which Hh signals at vertebrate cilia cause dissociation of inactive SuFu–Gli complexes, a process inhibited by PKA. PMID:20956384
Abrogation of Gli3 expression suppresses the growth of colon cancer cells via activation of p53

International Nuclear Information System (INIS)

Kang, Han Na; Oh, Sang Cheul; Kim, Jun Suk; Yoo, Young A.

2012-01-01

p53, the major human tumor suppressor, appears to be related to sonic hedgehog (Shh)–Gli-mediated tumorigenesis. However, the role of p53 in tumor progression by the Shh–Gli signaling pathway is poorly understood. Herein we investigated the critical regulation of Gli3–p53 in tumorigenesis of colon cancer cells and the molecular mechanisms underlying these effects. RT-PCR analysis indicated that the mRNA level of Shh and Gli3 in colon tumor tissues was significantly higher than corresponding normal tissues (P < 0.001). The inhibition of Gli3 by treatment with Gli3 siRNA resulted in a clear decrease in cell proliferation and enhanced the level of expression of p53 proteins compared to treatment with control siRNA. The half-life of p53 was dramatically increased by treatment with Gli3 siRNA. In addition, treatment with MG132 blocked MDM2-mediated p53 ubiquitination and degradation, and led to accumulation of p53 in Gli3 siRNA-overexpressing cells. Importantly, ectopic expression of p53 siRNA reduced the ability of Gli3 siRNA to suppress proliferation of those cells compared with the cells treated with Gli3 siRNA alone. Moreover, Gli3 siRNA sensitized colon cancer cells to treatment with anti-cancer agents (5-FU and bevacizumab). Taken together, our studies demonstrate that loss of Gli3 signaling leads to disruption of the MDM2–p53 interaction and strongly potentiate p53-dependent cell growth inhibition in colon cancer cells, indicating a basis for the rational use of Gli3 antagonists as a novel treatment option for colon cancer.
Melittin induces PTCH1 expression by down-regulating MeCP2 in human hepatocellular carcinoma SMMC-7721 cells

Energy Technology Data Exchange (ETDEWEB)

Wu, Xiaoqin; Zhao, Bin; Cheng, Yahui; Yang, Yang; Huang, Cheng; Meng, Xiaoming; Wu, Baoming; Zhang, Lei; Lv, Xiongwen; Li, Jun, E-mail: xqwu01@foxmail.com

2015-10-01

Hepatocellular carcinoma (HCC) has a high mortality rate worldwide and still remains to be a noticeable public health problem. Therefore, new remedies are urgently needed. Melittin, a major component of bee venom, is known to suppress cell growth in various cancers including HCC. However, the mechanism of the anticancer effect of melittin on HCC has not been fully elucidated. It has been reported that Methyl-CpG binding protein 2 (MeCP2) plays a key role in tumor proliferation, apoptosis, migration and invasion. In the present study, we found the high expression of MeCP2 in human HCC tissues and in the SMMC-7721 cell line. MeCP2 silencing inhibited cell proliferation, while over-expression of MeCP2 promoted cell growth in SMMC-7721 cells. It indicates that MeCP2 may be an attractive target for human HCC. We further found that melittin could inhibit cell proliferation by reducing MeCP2 expression in vitro. Interestingly, the inhibitory effect of melittin on cell proliferation was due to a delay in G{sub 0}/G{sub 1} cell cycle progression, without influencing cell apoptosis. Next, we investigated the potential molecular mechanisms and found that MeCP2 could modulate Shh signaling in SMMC-7721 cells. Further study indicates that melittin may induce the demethylation of PTCH1 promoter, resulting in the increased expression of PTCH1. Furthermore, the expression of Shh and GLI1 was significantly lowered upon treatment of melittin. These results suggest that melittin can block Shh signaling in vitro. In short, these results indicate that melittin inhibits cell proliferation by down-regulating MeCP2 through Shh signaling in SMMC-7721 cells. - Highlights: • MeCP2 plays a key role in the proliferation of human HCC cells. • Melittin reduces MeCP2 expression in vitro. • Melittin induces G{sub 0}/G{sub 1} cell cycle arrest in SMMC-7721 cells. • MeCP2 modulates the Shh signaling pathway in SMMC-7721 cells. • Melittin blocks the Shh signaling pathway in SMMC-7721 cells.
Identification of GLI Mutations in Patients With Hirschsprung Disease That Disrupt Enteric Nervous System Development in Mice.

Science.gov (United States)

Liu, Jessica Ai-Jia; Lai, Frank Pui-Ling; Gui, Hong-Sheng; Sham, Mai-Har; Tam, Paul Kwong-Hang; Garcia-Barcelo, Maria-Mercedes; Hui, Chi-Chung; Ngan, Elly Sau-Wai

2015-12-01

Hirschsprung disease is characterized by a deficit in enteric neurons, which are derived from neural crest cells (NCCs). Aberrant hedgehog signaling disrupts NCC differentiation and might cause Hirschsprung disease. We performed genetic analyses to determine whether hedgehog signaling is involved in pathogenesis. We performed deep-target sequencing of DNA from 20 patients with Hirschsprung disease (16 men, 4 women), and 20 individuals without (controls), and searched for mutation(s) in GLI1, GLI2, GLI3, SUFU, and SOX10. Biological effects of GLI mutations were tested in luciferase reporter assays using HeLa or neuroblastoma cell lines. Development of the enteric nervous system was studied in Sufu(f/f), Gli3(Δ699), Wnt1-Cre, and Sox10(NGFP) mice using immunohistochemical and whole-mount staining procedures to quantify enteric neurons and glia and analyze axon fasciculation, respectively. NCC migration was studied using time-lapse imaging. We identified 3 mutations in GLI in 5 patients with Hirschsprung disease but no controls; all lead to increased transcription of SOX10 in cell lines. SUFU, GLI, and SOX10 form a regulatory loop that controls the neuronal vs glial lineages and migration of NCCs. Sufu mutants mice had high Gli activity, due to loss of Sufu, disrupting the regulatory loop and migration of enteric NCCs, leading to defective axonal fasciculation, delayed gut colonization, or intestinal hypoganglionosis. The ratio of enteric neurons to glia correlated inversely with Gli activity. We identified mutations that increase GLI activity in patients with Hirschsprung disease. Disruption of the SUFU-GLI-SOX10 regulatory loop disrupts migration of NCCs and development of the enteric nervous system in mice. Copyright © 2015 AGA Institute. Published by Elsevier Inc. All rights reserved.
Aberrant expression of sonic hedgehog pathway in colon cancer and melanosis coli.

Science.gov (United States)

Wang, Zhong Chuan; Gao, Jun; Zi, Shu Ming; Yang, Ming; Du, Peng; Cui, Long

2013-08-01

To determine the hedgehog (Hh) signaling pathway correlated with the development of colon cancer and melanosis coli. Protein and mRNA levels of Hh signaling pathway components (sonic hedgehog [Shh], protein patched homolog 1 [Ptch 1], GLI family zinc finger 1 [Gli 1] and suppressor of fused homolog [Drosophila] [Sufu]) in 127 patients with colon cancer, 36 with melanosis coli and 20 adjacent normal mucosal tissues taken from surgical specimens were evaluated using antibody staining and quantitative real-time polymerase chain reaction. In adjacent normal tissue Shh and Ptch1, but not Gli1 or Sufu, were weakly expressed and mainly in the lining epithelium of the colonic mucosa. In cancerous tissues Shh and Gli1 were uniformly strong while Ptch1 was patchy and weak, and Sufu uniformly weak, which paralleled their levels of corresponding mRNA. Elevated protein levels of Shh and Ptch were significantly associated with mucinous colonic tissues. Elevated Sufu protein levels were positively correlated with the diameter and invasion of the tumor. In patients with melanosis coli, mRNA levels of Shh, Ptch1, Gli1 and Sufu were very low, which was similar to those of adjacent normal tissues; but protein levels of Shh, Ptch1 and Gli1, but not Sufu, were high, which was similar to those of cancerous tissues. The mRNA and protein levels of Hh pathway components are aberrantly elevated in colon cancer, which may be the potential molecular classification markers. Further studies are required to determine the role of melanosis coli in the colon tumorigenesis. © 2013 The Authors. Journal of Digestive Diseases © 2013 Wiley Publishing Asia Pty Ltd and Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine.
PTCH1 Germline Mutations and the Basaloid Follicular Hamartoma Values in the Tumor Spectrum of Basal Cell Carcinoma Syndrome (NBCCS).

Science.gov (United States)

Ponti, Giovanni; Manfredini, Marco; Pastorino, Lorenza; Maccaferri, Monia; Tomasi, Aldo; Pellacani, Giovanni

2018-01-01

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominantly inherited disorder characterized by multiple basal cell carcinomas (BCC), odontogenic tumors and various skeletal anomalies. Basaloid follicular hamartomas (BFHs) constitute rare neoplasms that can be detected in sporadic and familial settings as in the Basaloid Follicular Hamartoma Syndrome (BFHS). Although BFHS shares clinical, histopathological and genetic overlapping with the NBCCS, they are still considered two distinctive entities. The aim of our single-institution study was the analysis of a cohort of PTCH1-mutated patients in order to define clinical and biomolecular relationship between NBCCS and BFHs. In our study we evaluated PTCH1 gene-carrier probands affected by NBCCS to detect the incidence of BFHs and their correlation with this rare syndrome. Among probands we recognized 4 patients with BFHs. We found 15 germline PTCH1 mutations, uniformly distributed across the PTCH1 gene. Six of them had familial history of NBCCS, two of them were novel and have not been described previously. NBCCS and BFHS may be the same genetic entity and not two distinctive syndromes. The inclusion of BFH in the NBCCS cutaneous tumor spectrum might be useful for the recognition of misdiagnosed NBCCS cases that could benefit from tailored surveillance strategies. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.
Molecular and clinical analyses of Greig cephalopolysyndactyly and Pallister-Hall syndromes: Robust phenotype prediction from the type and position of GLI3 mutations

NARCIS (Netherlands)

Johnston, Jennifer J.; Olivos-Glander, Isabelle; Killoran, Christina; Elson, Emma; Turner, Joyce T.; Peters, Kathryn F.; Abbott, Margaret H.; Aughton, David J.; Aylsworth, Arthur S.; Bamshad, Michael J.; Booth, Carol; Curry, Cynthia J.; David, Albert; Dinulos, Mary Beth; Flannery, David B.; Fox, Michelle A.; Graham, John M.; Grange, Dorothy K.; Guttmacher, Alan E.; Hannibal, Mark C.; Henn, Wolfram; Hennekam, Raoul C. M.; Holmes, Lewis B.; Hoyme, H. Eugene; Leppig, Kathleen A.; Lin, Angela E.; Macleod, Patrick; Manchester, David K.; Marcelis, Carlo; Mazzanti, Laura; McCann, Emma; McDonald, Marie T.; Mendelsohn, Nancy J.; Moeschler, John B.; Moghaddam, Billur; Neri, Giovanni; Newbury-Ecob, Ruth; Pagon, Roberta A.; Phillips, John A.; Sadler, Laurie S.; Stoler, Joan M.; Tilstra, David; Walsh Vockley, Catherine M.; Zackai, Elaine H.; Zadeh, Touran M.; Brueton, Louise; Black, Graeme Charles M.; Biesecker, Leslie G.

2005-01-01

Mutations in the GLI3 zinc-finger transcription factor gene cause Greig cephalopolysyndactyly syndrome (GCPS) and Pallister-Hall syndrome (PHS), which are variable but distinct clinical entities. We hypothesized that GLI3 mutations that predict a truncated functional repressor protein cause PHS and
Development of 1-aryl-3-furanyl/thienyl-imidazopyridine templates for inhibitors against hypoxia inducible factor (HIF)-1 transcriptional activity.

Science.gov (United States)

Fuse, Shinichiro; Ohuchi, Toshiaki; Asawa, Yasunobu; Sato, Shinichi; Nakamura, Hiroyuki

2016-12-15

1,3-Disubstituted-imidazopyridines were designed for developing inhibitors against HIF-1 transcriptional activity. Designed compounds were rapidly synthesized from a key aromatic scaffold via microwave-assisted Suzuki-Miyaura coupling/CH direct arylation sequence. Evaluation of ability to inhibit the hypoxia induced transcriptional activity of HIF-1 revealed that the compound 2i and 3a retained the same level of the inhibitory activity comparing with that of known inhibitor, YC-1 (1). Identified, readily accessible 1-aryl-3-furanyl/thienyl-imidazopyridine templates should be useful for future drug development. Copyright Â© 2016 Elsevier Ltd. All rights reserved.
Constitutive activation of Gli2 impairs bone formation in postnatal growing mice.

Directory of Open Access Journals (Sweden)

Kyu Sang Joeng

Full Text Available Indian hedgehog (Ihh signaling is indispensable for osteoblast differentiation during endochondral bone development in the mouse embryo. We have previously shown that the Gli2 transcription activator critically mediates Ihh function in osteoblastogenesis. To explore the possibility that activation of Hedgehog (Hh signaling may enhance bone formation, we generated mice that expressed a constitutively active form of Gli2 in the Osx-lineage cells. Unexpectedly, these mice exhibited severe osteopenia due to a marked decrease in osteoblast number and function, although bone resorption was not affected. Quantitative analyses of the molecular markers indicated that osteoblast differentiation was impaired in the mutant mouse. However, the osteoblast-lineage cells isolated from these mice exhibited more robust osteoblast differentiation than normal in vitro. Similarly, pharmacological stimulation of Hh signaling enhanced osteoblast differentiation from Osx-expressing cells isolated from the wild-type mouse. Thus, even though Hh signaling directly promotes osteoblast differentiation in vitro, constitutive activation of this pathway impairs bone formation in vivo, perhaps through an indirect mechanism.
Structural basis of SUFU–GLI interaction in human Hedgehog signalling regulation

International Nuclear Information System (INIS)

Cherry, Amy L.; Finta, Csaba; Karlström, Mikael; Jin, Qianren; Schwend, Thomas; Astorga-Wells, Juan; Zubarev, Roman A.; Del Campo, Mark; Criswell, Angela R.; Sanctis, Daniele de; Jovine, Luca; Toftgård, Rune

2013-01-01

Crystal and small-angle X-ray scattering structures of full-length human SUFU alone and in complex with the conserved SYGHL motif from GLI transcription factors show major conformational changes associated with binding and reveal an intrinsically disordered region crucial for pathway activation. Hedgehog signalling plays a fundamental role in the control of metazoan development, cell proliferation and differentiation, as highlighted by the fact that its deregulation is associated with the development of many human tumours. SUFU is an essential intracellular negative regulator of mammalian Hedgehog signalling and acts by binding and modulating the activity of GLI transcription factors. Despite its central importance, little is known about SUFU regulation and the nature of SUFU–GLI interaction. Here, the crystal and small-angle X-ray scattering structures of full-length human SUFU and its complex with the key SYGHL motif conserved in all GLIs are reported. It is demonstrated that GLI binding is associated with major conformational changes in SUFU, including an intrinsically disordered loop that is also crucial for pathway activation. These findings reveal the structure of the SUFU–GLI interface and suggest a mechanism for an essential regulatory step in Hedgehog signalling, offering possibilities for the development of novel pathway modulators and therapeutics
Structural basis of SUFU–GLI interaction in human Hedgehog signalling regulation

Energy Technology Data Exchange (ETDEWEB)

Cherry, Amy L.; Finta, Csaba; Karlström, Mikael; Jin, Qianren; Schwend, Thomas [Karolinska Institutet, Novum, Hälsovägen 7, SE-141 83 Huddinge (Sweden); Astorga-Wells, Juan [Karolinska Institutet, Scheeles väg 2, SE-171 77 Stockholm (Sweden); Biomotif AB, Enhagsvägen 7, SE-182 12 Danderyd (Sweden); Zubarev, Roman A. [Karolinska Institutet, Scheeles väg 2, SE-171 77 Stockholm (Sweden); Del Campo, Mark; Criswell, Angela R. [Rigaku Americas Corporation, 9009 New Trails Drive, The Woodlands, TX 77381 (United States); Sanctis, Daniele de [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, 38043 Grenoble (France); Jovine, Luca, E-mail: luca.jovine@ki.se; Toftgård, Rune, E-mail: luca.jovine@ki.se [Karolinska Institutet, Novum, Hälsovägen 7, SE-141 83 Huddinge (Sweden)

2013-12-01

Crystal and small-angle X-ray scattering structures of full-length human SUFU alone and in complex with the conserved SYGHL motif from GLI transcription factors show major conformational changes associated with binding and reveal an intrinsically disordered region crucial for pathway activation. Hedgehog signalling plays a fundamental role in the control of metazoan development, cell proliferation and differentiation, as highlighted by the fact that its deregulation is associated with the development of many human tumours. SUFU is an essential intracellular negative regulator of mammalian Hedgehog signalling and acts by binding and modulating the activity of GLI transcription factors. Despite its central importance, little is known about SUFU regulation and the nature of SUFU–GLI interaction. Here, the crystal and small-angle X-ray scattering structures of full-length human SUFU and its complex with the key SYGHL motif conserved in all GLIs are reported. It is demonstrated that GLI binding is associated with major conformational changes in SUFU, including an intrinsically disordered loop that is also crucial for pathway activation. These findings reveal the structure of the SUFU–GLI interface and suggest a mechanism for an essential regulatory step in Hedgehog signalling, offering possibilities for the development of novel pathway modulators and therapeutics.
Activation of the hedgehog pathway in advanced prostate cancer

Directory of Open Access Journals (Sweden)

McCormick Frank

2004-10-01

Full Text Available Abstract Background The hedgehog pathway plays a critical role in the development of prostate. However, the role of the hedgehog pathway in prostate cancer is not clear. Prostate cancer is the second most prevalent cause of cancer death in American men. Therefore, identification of novel therapeutic targets for prostate cancer has significant clinical implications. Results Here we report that activation of the hedgehog pathway occurs frequently in advanced human prostate cancer. We find that high levels of hedgehog target genes, PTCH1 and hedgehog-interacting protein (HIP, are detected in over 70% of prostate tumors with Gleason scores 8–10, but in only 22% of tumors with Gleason scores 3–6. Furthermore, four available metastatic tumors all have high expression of PTCH1 and HIP. To identify the mechanism of the hedgehog signaling activation, we examine expression of Su(Fu protein, a negative regulator of the hedgehog pathway. We find that Su(Fu protein is undetectable in 11 of 27 PTCH1 positive tumors, two of them contain somatic loss-of-function mutations of Su(Fu. Furthermore, expression of sonic hedgehog protein is detected in majority of PTCH1 positive tumors (24 out of 27. High levels of hedgehog target genes are also detected in four prostate cancer cell lines (TSU, DU145, LN-Cap and PC3. We demonstrate that inhibition of hedgehog signaling by smoothened antagonist, cyclopamine, suppresses hedgehog signaling, down-regulates cell invasiveness and induces apoptosis. In addition, cancer cells expressing Gli1 under the CMV promoter are resistant to cyclopamine-mediated apoptosis. All these data suggest a significant role of the hedgehog pathway for cellular functions of prostate cancer cells. Conclusion Our data indicate that activation of the hedgehog pathway, through loss of Su(Fu or overexpression of sonic hedgehog, may involve tumor progression and metastases of prostate cancer. Thus, targeted inhibition of hedgehog signaling may have
Menin and RNF20 recruitment is associated with dynamic histone modifications that regulate signal transducer and activator of transcription 1 (STAT1-activated transcription of the interferon regulatory factor 1 gene (IRF1

Directory of Open Access Journals (Sweden)

Buro Lauren J

2010-09-01

Full Text Available Abstract Background Signal transducer and activator of transcription (STAT activation of gene expression is both rapid and transient, and when properly executed it affects growth, differentiation, homeostasis and the immune response, but when dysregulated it contributes to human disease. Transcriptional activation is regulated by alterations to the chromatin template. However, the role of histone modification at gene loci that are activated for transcription in response to STAT signaling is poorly defined. Results Using chromatin immunoprecipitation, we profiled several histone modifications during STAT1 activation of the interferon regulatory factor 1 gene (IRF1. Methylated lysine histone proteins H3K4me2, H3K4me3, H3K79me3, H3K36me3 and monoubiquitinated histone ubH2B are dynamic and correlate with interferon (IFNγ induction of STAT1 activity. Chemical inhibition of H3K4 methylation downregulates IRF1 transcription and decreases RNA polymerase II (Pol II occupancy at the IRF1 promoter. MEN1, a component of a complex proteins associated with Set1 (COMPASS-like complex and the hBRE1 component, RNF20, are localized to IRF1 in the uninduced state and are further recruited when IRF1 is activated. RNAi-mediated depletion of RNF20 lowers both ubH2B and H3K4me3, but surprisingly, upregulates IFNγ induced IRF1 transcription. The dynamics of phosphorylation in the C-terminal domain (CTD of Pol II are disrupted during gene activation as well. Conclusions H2B monoubiquitination promotes H3K4 methylation, but the E3 ubiquitin ligase, RNF20, is repressive of inducible transcription at the IRF1 gene locus, suggesting that ubH2B can, directly or indirectly, affect Pol II CTD phosphorylation cycling to exert control on ongoing transcription.
Analysis of PGC-1α variants Gly482Ser and Thr612Met concerning their PPARγ2-coactivation function

International Nuclear Information System (INIS)

Nitz, Inke; Ewert, Agnes; Klapper, Maja; Doering, Frank

2007-01-01

Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) is a cofactor involved in adaptive thermogenesis, fatty acid oxidation, and gluconeogenesis. Dysfunctions of this protein are likely to contribute to the development of obesity and the metabolic syndrome. This is in part but not definitely confirmed by results of population studies. The aim of this study was to investigate if common genetic variants rs8192678 (Gly482Ser) and rs3736265 (Thr612Met) in the PGC-1α gene lead to a functional consequence in cofactor activity using peroxisome proliferator-activated receptor-γ 2 (PPARγ2) as interacting transcription factor. Reporter gene assays in HepG2 cells with wildtype and mutant proteins of both PGC1α and PPARγ2 (Pro12Ala, rs1801282) using the acyl-CoA-binding protein (ACBP) promoter showed no difference in coactivator activity. This is First study implicating that the Gly482Ser and Thr612Met polymorphisms in PGC-1α and Pro12Ala polymorphism in PPARγ2 do not affect the functional integrity of these proteins
A mechanism for vertebrate Hedgehog signaling: recruitment to cilia and dissociation of SuFu–Gli protein complexes

OpenAIRE

Tukachinsky, Hanna; Lopez, Lyle V.; Salic, Adrian

2010-01-01

In vertebrates, Hedgehog (Hh) signaling initiated in primary cilia activates the membrane protein Smoothened (Smo) and leads to activation of Gli proteins, the transcriptional effectors of the pathway. In the absence of signaling, Gli proteins are inhibited by the cytoplasmic protein Suppressor of Fused (SuFu). It is unclear how Hh activates Gli and whether it directly regulates SuFu. We find that Hh stimulation quickly recruits endogenous SuFu–Gli complexes to cilia, suggesting a model in wh...
Studies of the Gly482Ser polymorphism of the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) gene in Danish subjects with the metabolic syndrome

DEFF Research Database (Denmark)

Ambye, L; Rasmussen, S; Fenger, Mogens

2005-01-01

The peroxisome proliferator-activated receptor gamma co-activator 1alpha (PGC-1alpha) is a novel transcriptional co-activator that holds an important role in lipid and glucose metabolism. PGC-1alpha is a candidate gene for the metabolic syndrome (MS) as well as type 2 diabetes. Recent studies...... related to this syndrome. The variant was examined, using PCR-RFLP, in the DanMONICA cohort comprising a population-based sample of 2349 subjects. MS was defined using the National Cholesterol Education Program -- Adult Treatment Panel III (NCEP-ATPIII) criteria. The allelic frequency of the Ser482 allele...... and insulin secretion, 24-ambulatory blood pressure or left ventricular mass index. In conclusion, the Gly482Ser polymorphism of the PGC-1alpha gene is not associated with the metabolic syndrome, related quantitative traits or cardiac hypertrophy among Danish Caucasian subjects...
Transcriptional activity of Pax3 is co-activated by TAZ

International Nuclear Information System (INIS)

Murakami, Masao; Tominaga, Junji; Makita, Ryosuke; Uchijima, Yasunobu; Kurihara, Yukiko; Nakagawa, Osamu; Asano, Tomoichiro; Kurihara, Hiroki

2006-01-01

Pax3 is a transcription factor which functions in embryonic development and human diseases. In a yeast two-hybrid screen with full-length Pax3 as bait, we isolated a clone encoding transcriptional co-activator with PDZ-binding motif (TAZ) from an E10.5 mouse embryo cDNA library. Co-immunoprecipitation and nuclear co-localization of TAZ with Pax3 suggest that their association is functionally relevant. In situ hybridization revealed TAZ and Pax3 expression to partially overlap in the paraxial mesoderm, limb buds, and the neural tube. In C2C12 myoblast cells and NIH3T3 cells, TAZ enhanced the transcriptional activity of Pax3 on artificial and microphthalmia-associated transcription factor promoter-luciferase constructs, suggesting that TAZ can function as a co-activator of Pax3. Functional interaction between Pax3 and TAZ may provide a clue to clarifying the mechanism by which Pax3 serves as a transcriptional activator during embryogenesis

Expression of the glioma-associated oncogene homolog (GLI) 1 in human breast cancer is associated with unfavourable overall survival

International Nuclear Information System (INIS)

Haaf, Anette ten; Bektas, Nuran; Serenyi, Sonja von; Losen, Inge; Arweiler, Elfriede Christel; Hartmann, Arndt; Knüchel, Ruth; Dahl, Edgar

2009-01-01

The transcription factor GLI1, a member of the GLI subfamily of Krüppel-like zinc finger proteins is involved in signal transduction within the hedgehog pathway. Aberrant hedgehog signalling has been implicated in the development of different human tumour entities such as colon and lung cancer and increased GLI1 expression has been found in these tumour entities as well. In this study we questioned whether GLI1 expression might also be important in human breast cancer development. Furthermore we correlated GLI1 expression with histopathological and clinical data to evaluate whether GLI1 could represent a new prognostic marker in breast cancer treatment. Applying semiquantitative realtime PCR analysis and immunohistochemistry (IHC) GLI1 expression was analysed in human invasive breast carcinomas (n = 229) in comparison to normal human breast tissues (n = 58). GLI1 mRNA expression was furthermore analysed in a set of normal (n = 3) and tumourous breast cell lines (n = 8). IHC data were statistically interpreted using SPSS version 14.0. Initial analysis of GLI1 mRNA expression in a small cohort of (n = 5) human matched normal and tumourous breast tissues showed first tendency towards GLI1 overexpression in human breast cancers. However only a small sample number was included into these analyses and values for GLI1 overexpression were statistically not significant (P = 0.251, two-tailed Mann-Whitney U-test). On protein level, nuclear GLI1 expression in breast cancer cells was clearly more abundant than in normal breast epithelial cells (P = 0.008, two-tailed Mann-Whitney U-test) and increased expression of GLI1 protein in breast tumours significantly correlated with unfavourable overall survival (P = 0.019), but also with higher tumour stage (P < 0.001) and an increased number of tumour-positive axillar lymph nodes (P = 0.027). Interestingly, a highly significant correlation was found between GLI1 expression and the expression of SHH, a central upstream molecule of
New insights into genotype-phenotype correlation for GLI3 mutations.

Science.gov (United States)

Démurger, Florence; Ichkou, Amale; Mougou-Zerelli, Soumaya; Le Merrer, Martine; Goudefroye, Géraldine; Delezoide, Anne-Lise; Quélin, Chloé; Manouvrier, Sylvie; Baujat, Geneviève; Fradin, Mélanie; Pasquier, Laurent; Megarbané, André; Faivre, Laurence; Baumann, Clarisse; Nampoothiri, Sheela; Roume, Joëlle; Isidor, Bertrand; Lacombe, Didier; Delrue, Marie-Ange; Mercier, Sandra; Philip, Nicole; Schaefer, Elise; Holder, Muriel; Krause, Amanda; Laffargue, Fanny; Sinico, Martine; Amram, Daniel; André, Gwenaelle; Liquier, Alain; Rossi, Massimiliano; Amiel, Jeanne; Giuliano, Fabienne; Boute, Odile; Dieux-Coeslier, Anne; Jacquemont, Marie-Line; Afenjar, Alexandra; Van Maldergem, Lionel; Lackmy-Port-Lis, Marylin; Vincent-Delorme, Catherine; Chauvet, Marie-Liesse; Cormier-Daire, Valérie; Devisme, Louise; Geneviève, David; Munnich, Arnold; Viot, Géraldine; Raoul, Odile; Romana, Serge; Gonzales, Marie; Encha-Razavi, Ferechte; Odent, Sylvie; Vekemans, Michel; Attie-Bitach, Tania

2015-01-01

The phenotypic spectrum of GLI3 mutations includes autosomal dominant Greig cephalopolysyndactyly syndrome (GCPS) and Pallister-Hall syndrome (PHS). PHS was first described as a lethal condition associating hypothalamic hamartoma, postaxial or central polydactyly, anal atresia and bifid epiglottis. Typical GCPS combines polysyndactyly of hands and feet and craniofacial features. Genotype-phenotype correlations have been found both for the location and the nature of GLI3 mutations, highlighting the bifunctional nature of GLI3 during development. Here we report on the molecular and clinical study of 76 cases from 55 families with either a GLI3 mutation (49 GCPS and 21 PHS), or a large deletion encompassing the GLI3 gene (6 GCPS cases). Most of mutations are novel and consistent with the previously reported genotype-phenotype correlation. Our results also show a correlation between the location of the mutation and abnormal corpus callosum observed in some patients with GCPS. Fetal PHS observations emphasize on the possible lethality of GLI3 mutations and extend the phenotypic spectrum of malformations such as agnathia and reductional limbs defects. GLI3 expression studied by in situ hybridization during human development confirms its early expression in target tissues.
New insights into genotype–phenotype correlation for GLI3 mutations

Science.gov (United States)

Démurger, Florence; Ichkou, Amale; Mougou-Zerelli, Soumaya; Le Merrer, Martine; Goudefroye, Géraldine; Delezoide, Anne-Lise; Quélin, Chloé; Manouvrier, Sylvie; Baujat, Geneviève; Fradin, Mélanie; Pasquier, Laurent; Megarbané, André; Faivre, Laurence; Baumann, Clarisse; Nampoothiri, Sheela; Roume, Joëlle; Isidor, Bertrand; Lacombe, Didier; Delrue, Marie-Ange; Mercier, Sandra; Philip, Nicole; Schaefer, Elise; Holder, Muriel; Krause, Amanda; Laffargue, Fanny; Sinico, Martine; Amram, Daniel; André, Gwenaelle; Liquier, Alain; Rossi, Massimiliano; Amiel, Jeanne; Giuliano, Fabienne; Boute, Odile; Dieux-Coeslier, Anne; Jacquemont, Marie-Line; Afenjar, Alexandra; Van Maldergem, Lionel; Lackmy-Port-Lis, Marylin; Vincent- Delorme, Catherine; Chauvet, Marie-Liesse; Cormier-Daire, Valérie; Devisme, Louise; Geneviève, David; Munnich, Arnold; Viot, Géraldine; Raoul, Odile; Romana, Serge; Gonzales, Marie; Encha-Razavi, Ferechte; Odent, Sylvie; Vekemans, Michel; Attie-Bitach, Tania

2015-01-01

The phenotypic spectrum of GLI3 mutations includes autosomal dominant Greig cephalopolysyndactyly syndrome (GCPS) and Pallister–Hall syndrome (PHS). PHS was first described as a lethal condition associating hypothalamic hamartoma, postaxial or central polydactyly, anal atresia and bifid epiglottis. Typical GCPS combines polysyndactyly of hands and feet and craniofacial features. Genotype–phenotype correlations have been found both for the location and the nature of GLI3 mutations, highlighting the bifunctional nature of GLI3 during development. Here we report on the molecular and clinical study of 76 cases from 55 families with either a GLI3 mutation (49 GCPS and 21 PHS), or a large deletion encompassing the GLI3 gene (6 GCPS cases). Most of mutations are novel and consistent with the previously reported genotype–phenotype correlation. Our results also show a correlation between the location of the mutation and abnormal corpus callosum observed in some patients with GCPS. Fetal PHS observations emphasize on the possible lethality of GLI3 mutations and extend the phenotypic spectrum of malformations such as agnathia and reductional limbs defects. GLI3 expression studied by in situ hybridization during human development confirms its early expression in target tissues. PMID:24736735
Phe-Gly dipeptidomimetics designed for the di-/tripeptide transporters PEPT1 and PEPT2

DEFF Research Database (Denmark)

Våbenø, Jon; Lejon, Tore; Nielsen, Carsten Uhd

2004-01-01

A series of five Phe-Gly dipeptidomimetics containing different amide bond replacements have been synthesized in a facile way from the readily available unsaturated ketoester 1, and their affinities for the di-/tripeptide transporters hPEPT1 (Caco-2 cells) and rPEPT2 (SKPT cells) were tested...... information about the importance of flexibility and of the stereochemistry at the C(4)-position for this class of compounds. Furthermore, the intracellular uptake of 2a-4a in Caco-2 cells was investigated, showing a 3-fold reduction of the uptake of 2a in the presence of the competetive inhibitor Gly......-Pro, indicating contribution from an active transport component. No active uptake of 3a and 4a was observed. Transepithelial transport studies also indicated active transport of 2a across Caco-2 monolayers....
Reciprocal Regulation of Hypoxia-Inducible Factor 2α and GLI1 Expression Associated With the Radioresistance of Renal Cell Carcinoma

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Zhou, Jiancheng [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Wu, Kaijie [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Gao, Dexuan [Department of Urology, Shandong Provincial Hospital affiliated with Shandong University, Ji' nan (China); Zhu, Guodong; Wu, Dapeng; Wang, Xinyang; Chen, Yule; Du, Yuefeng; Song, Wenbin; Ma, Zhenkun [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China); Authement, Craig; Saha, Debabrata [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); Hsieh, Jer-Tsong, E-mail: jt.hsieh@utsouthwestern.edu [Department of Urology, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas (United States); He, Dalin, E-mail: dalinhe@yahoo.com [Department of Urology, First Affiliated Hospital of Medical School, Xi' an Jiaotong University, Xi' an (China)

2014-11-15

Purpose: Renal cell carcinoma (RCC) is often considered a radioresistant tumor, but the molecular mechanism underlying its radioresistance is poorly understood. This study explored the roles of hypoxia-inducible factor 2α (HIF2α) and sonic hedgehog (SHH)-GLI1 signaling in mediating the radioresistance of RCC cells and to unveil the interaction between these 2 signaling pathways. Methods and Materials: The activities of SHH-GLI1 signaling pathway under normoxia and hypoxia in RCC cells were examined by real-time polymerase chain reaction, Western blot, and luciferase reporter assay. The expression of HIF2α and GLI1 in RCC patients was examined by immunohistochemistry, and their correlation was analyzed. Furthermore, RCC cells were treated with HIF2α-specific shRNA (sh-HIF2α), GLI1 inhibitor GANT61, or a combination to determine the effect of ionizing radiation (IR) on RCC cells based on clonogenic assay and double-strand break repair assay. Results: RCC cells exhibited elevated SHH-GLI1 activities under hypoxia, which was mediated by HIF2α. Hypoxia induced GLI1 activation through SMO-independent pathways that could be ablated by PI3K inhibitor or MEK inhibitor. Remarkably, the SHH-GLI1 pathway also upregulated HIF2α expression in normoxia. Apparently, there was a positive correlation between HIF2α and GLI1 expression in RCC patients. The combination of sh-HIF2α and GLI1 inhibitor significantly sensitized RCC cells to IR. Conclusions: Cross-talk between the HIF2α and SHH-GLI1 pathways was demonstrated in RCC. Cotargeting these 2 pathways, significantly sensitizing RCC cells to IR, provides a novel strategy for RCC treatment.
GlyT1 Inhibitor NFPS Exerts Neuroprotection via GlyR Alpha1 Subunit in the Rat Model of Transient Focal Cerebral Ischaemia and Reperfusion

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Baosheng Huang

2016-05-01

Full Text Available Background/Aims: Glycine is a strychnine-sensitive inhibitory neurotransmitter in the central nervous system (CNS, especially in the spinal cord, brainstem, and retina. The objective of the present study was to investigate the potential neuroprotective effects of GlyT1 inhibitor N [3-(4'-fluorophenyl-3-(4'-phenylphenoxy propyl] sarcosine (NFPS in the rat model of experimental stroke. Methods: In vivo ischaemia was induced by transient middle cerebral artery occlusion (tMCAO. The methods of Western Blotting, Nissl Staining and Morris water maze methods were applied to analyze the anti-ischaemia mechanism. Results: The results showed that high dose of NFPS (H-NFPS significantly reduced infarct volume, neuronal injury and the expression of cleaved caspase-3, enhanced Bcl-2/Bax, and improved spatial learning deficits which were administered three hours after transient middle cerebral artery occlusion (tMCAO induction in rats, while, low dose of NFPS (L-NFPS exacerbated the injury of ischaemia. These findings suggested that low and high dose of NFPS produced opposite effects. Importantly, it was demonstrated that H-NFPS-dependent neuronal protection was inverted by salicylate (Sal, a specific GlyR ɑ1 antagonist. Such effects could probably be attributed to the enhanced glycine level in both synaptic and extrasynaptic clefts and the subsequently altered extrasynaptic GlyRs and their subtypes. Conclusions: These data imply that GlyT1 inhibitor NFPS may be a novel target for clinical treatment of transient focal cerebral ischaemia and reperfusion which are associated with altered GlyR alpha 1 subunits.
Genetic variations and alternative splicing. The Glioma associated oncogene 1, GLI1.

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Peter eZaphiropoulos

2012-07-01

Full Text Available Alternative splicing is a post-transcriptional regulatory process that is attaining stronger recognition as a modulator of gene expression. Alternative splicing occurs when the primary RNA transcript is differentially processed into more than one mature RNAs. This is the result of a variable definition/inclusion of the exons, the sequences that are excised from the primary RNA to form the mature RNAs. Consequently, RNA expression can generate a collection of differentially spliced RNAs, which may distinctly influence subsequent biological events, such as protein synthesis or other biomolecular interactions. Still the mechanisms that control exon definition and exon inclusion are not fully clarified. This mini-review highlights advances in this field as well as the impact of single nucleotide polymorphisms in affecting splicing decisions. The Glioma associated oncogene 1, GLI1, is taken as an example in addressing the role of nucleotide substitutions for splicing regulation.
Transcriptional activation of Mina by Sp1/3 factors.

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Lian, Shangli; Potula, Hari Hara S K; Pillai, Meenu R; Van Stry, Melanie; Koyanagi, Madoka; Chung, Linda; Watanabe, Makiko; Bix, Mark

2013-01-01

Mina is an epigenetic gene regulatory protein known to function in multiple physiological and pathological contexts, including pulmonary inflammation, cell proliferation, cancer and immunity. We showed previously that the level of Mina gene expression is subject to natural genetic variation linked to 21 SNPs occurring in the Mina 5' region. In order to explore the mechanisms regulating Mina gene expression, we set out to molecularly characterize the Mina promoter in the region encompassing these SNPs. We used three kinds of assays--reporter, gel shift and chromatin immunoprecipitation--to analyze a 2 kb genomic fragment spanning the upstream and intron 1 regions flanking exon 1. Here we discovered a pair of Mina promoters (P1 and P2) and a P1-specific enhancer element (E1). Pharmacologic inhibition and siRNA knockdown experiments suggested that Sp1/3 transcription factors trigger Mina expression through additive activity targeted to a cluster of four Sp1/3 binding sites forming the P1 promoter. These results set the stage for comprehensive analysis of Mina gene regulation from the context of tissue specificity, the impact of inherited genetic variation and the nature of upstream signaling pathways.
Mutations in PTCH and XPA heterozygosity in x-irradiated subjects with high multiplicity of basal cell carcinomas

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Burns, F.J.; Zhao, P.; Roy, N.; Shore, R.; Loomis, C. [NYU, New York, NY (United States). School of Medicine

2000-07-01

Basal cell carcinomas (BCCs) were obtained from subjects who had been treated with x-ray for tinea capitis at mean age 8 yr (average dose 3.0 Gy) and who have developed multiple (>5) skin cancers 35-40 years later. By allelic loss analysis, 9/10 tumors from 3 patients exhibited loss of heterozygosity (LOH) in one or more microsatellite markers in chromosome location 9q22.3. The xeroderma pigmentosum A (XPA) and PTCH (nevoid BCC syndrome (NBCCS)) genes are located in region 9q22.3, and often LOH in the region means that alleles of both genes are lost. Mutations were found in the undeleted PTCH allele in 2/9 BCCs, which is consistent with the two-allele inactivation model. A similar analysis for the XPA gene showed 5/9 BCCs with probable inactivating mutations. In 1 patient 5/5 cancers and normal blood showed the same 14 base deletion in codon 256-260 indicating this person was an XPA heterozygote. The same 5 cancers exhibited LOH in region 9q22.3 making it likely that 1 allele of both PTCH and XPA were lost. These results suggest how 2 genes could combine to produce an increase in susceptibility to X-ray-induced carcinogenesis in connection with UV as a second exogenous carcinogen (Supported by NIEHS and NCI). (author)
Signal interaction of Hedgehog/GLI and epidermal growth factor receptor signaling in cancer development

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Eberl, M.

2012-01-01

The subject of this PhD thesis is based on the cooperation of Hedgehog (HH)/GLI with epidermal growth factor receptor (EGFR) signaling synergistically promoting oncogenic transformation and cancer growth. In previous studies we have demonstrated that the HH/GLI and EGFR signaling pathways interact synergistically resulting not only in selective induction of HH/GLI-EGFR target genes, but also in the onset of oncogenic transformation and tumor formation (Kasper, Schnidar et al. 2006; Schnidar, Eberl et al. 2009). However, the molecular key mediators acting downstream of HH/GLI and EGFR signal cooperation were largely unknown and the in vivo evidence for the therapeutic relevance of HH/GLI and EGFR signal cooperation in HH-associated cancers was lacking. During my PhD thesis I could demonstrate that the integration of EGFR and HH/GLI signaling involves activation of RAS/MEK/ERK and JUN/AP1 signaling in response to EGFR activation. Furthermore I succeeded in identifying genes, including stem cell- (SOX2, SOX9), tumor growth- (JUN, TGFA, FGF19) and metastasis-associated genes (SPP1/osteopontin, CXCR4) that showed synergistic transcriptional activation by HH/GLI-EGFR signal integration. Importantly, I could demonstrate that these genes arrange themselves within a stable interdependent signaling network, which is required for in vivo growth of basal cell carcinoma (BCC) and tumor-initiating pancreatic cancer cells. These data validate EGFR signaling as additional drug target in HH/GLI driven cancers and provide new therapeutic strategies based on combined targeting of cooperative HH/GLI-EGFR signaling and selected downstream target genes (Eberl, Klingler et al. 2012). (author) [de
Inhibition of transcriptional activity of c-JUN by SIRT1

International Nuclear Information System (INIS)

Gao Zhanguo; Ye Jianping

2008-01-01

c-JUN is a major component of heterodimer transcription factor AP-1 (Activator Protein-1) that activates gene transcription in cell proliferation, inflammation and stress responses. SIRT1 (Sirtuin 1) is a histone deacetylase that controls gene transcription through modification of chromatin structure. However, it is not clear if SIRT1 regulates c-JUN activity in the control of gene transcription. Here, we show that SIRT1 associated with c-JUN in co-immunoprecipitation of whole cell lysate, and inhibited the transcriptional activity of c-JUN in the mammalian two hybridization system. SIRT1 was found in the AP-1 response element in the matrix metalloproteinase-9 (MMP9) promoter DNA leading to inhibition of histone 3 acetylation as shown in a ChIP assay. The SIRT1 signal was reduced by the AP-1 activator PMA, and induced by the SIRT1 activator Resveratrol in the promoter DNA. SIRT1-mediaetd inhibition of AP-1 was demonstrated in the MMP9 gene expression at the gene promoter, mRNA and protein levels. In mouse embryonic fibroblast (MEF) with SIRT1 deficiency (SIRT1 -/- ), mRNA and protein of MMP9 were increased in the basal condition, and the inhibitory activity of Resveratrol was significantly attenuated. Glucose-induced MMP9 expression was also inhibited by SIRT1 in response to Resveratrol. These data consistently suggest that SIRT1 directly inhibits the transcriptional activity of AP-1 by targeting c-JUN
Identification of a 3rd Na+ Binding Site of the Glycine Transporter, GlyT2.

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Nandhitha Subramanian

Full Text Available The Na+/Cl- dependent glycine transporters GlyT1 and GlyT2 regulate synaptic glycine concentrations. Glycine transport by GlyT2 is coupled to the co-transport of three Na+ ions, whereas transport by GlyT1 is coupled to the co-transport of only two Na+ ions. These differences in ion-flux coupling determine their respective concentrating capacities and have a direct bearing on their functional roles in synaptic transmission. The crystal structures of the closely related bacterial Na+-dependent leucine transporter, LeuTAa, and the Drosophila dopamine transporter, dDAT, have allowed prediction of two Na+ binding sites in GlyT2, but the physical location of the third Na+ site in GlyT2 is unknown. A bacterial betaine transporter, BetP, has also been crystallized and shows structural similarity to LeuTAa. Although betaine transport by BetP is coupled to the co-transport of two Na+ ions, the first Na+ site is not conserved between BetP and LeuTAa, the so called Na1' site. We hypothesized that the third Na+ binding site (Na3 site of GlyT2 corresponds to the BetP Na1' binding site. To identify the Na3 binding site of GlyT2, we performed molecular dynamics (MD simulations. Surprisingly, a Na+ placed at the location consistent with the Na1' site of BetP spontaneously dissociated from its initial location and bound instead to a novel Na3 site. Using a combination of MD simulations of a comparative model of GlyT2 together with an analysis of the functional properties of wild type and mutant GlyTs we have identified an electrostatically favorable novel third Na+ binding site in GlyT2 formed by Trp263 and Met276 in TM3, Ala481 in TM6 and Glu648 in TM10.
The expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats

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Katayama, Seiichi; Ashizawa, Koji; Gohma, Hiroshi; Fukuhara, Tadahiro; Narumi, Kazunori; Tsuzuki, Yasuhiro; Tatemoto, Hideki; Nakada, Tadashi; Nagai, Kenji

2006-01-01

The objective of this study was to investigate the effects of estrogen receptor (ER) agonists and an ER antagonist on the expression of Hedgehog genes (Indian hedgehog: Ihh; Desert hedgehog: Dhh) and Hedgehog target genes (Patched 1: Ptc1; glioma-associated oncogene homolog 1: Gli1; chicken ovalbumin upstream promoter transcription factor II: Coup-TfII) in the rat uterus. Immature female rats were administered once with 17α-ethynyl estradiol (EE, an ER agonist), propyl pyrazole triole (PPT, an ERα-selective agonist), diarylpropionitrile (DPN, an ERβ-selective agonist), or ICI 182,780 (an ER antagonist). Expression of mRNA for Ihh, Dhh, and Ptc1 was dose-dependently downregulated by EE in the uterus of immature rats, mediated by ER as confirmed by coadministration of ICI 182,780. The mRNA expression levels of Ptc1, Gli1, and Coup-TfII were simultaneously downregulated during the period in which the mRNA expression levels of Ihh and Dhh were downregulated in the uterus after administration of EE. PPT downregulated the transcription of Ihh, Dhh, Ptc1, Gli1, and Coup-TfII, indicating that expression of these genes was regulated by the ERα-dependent pathway. DPN also downregulated the transcription of Ihh and Dhh, although the effect was weaker than that of PPT, indicating that the regulation of uterine Ihh and Dhh transcription was also affected by the ERβ-dependent pathway. These results suggest that the expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats
The expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats.

Science.gov (United States)

Katayama, Seiichi; Ashizawa, Koji; Gohma, Hiroshi; Fukuhara, Tadahiro; Narumi, Kazunori; Tsuzuki, Yasuhiro; Tatemoto, Hideki; Nakada, Tadashi; Nagai, Kenji

2006-12-15

The objective of this study was to investigate the effects of estrogen receptor (ER) agonists and an ER antagonist on the expression of Hedgehog genes (Indian hedgehog: Ihh; Desert hedgehog: Dhh) and Hedgehog target genes (Patched 1: Ptc1; glioma-associated oncogene homolog 1: Gli1; chicken ovalbumin upstream promoter transcription factor II: Coup-TfII) in the rat uterus. Immature female rats were administered once with 17alpha-ethynyl estradiol (EE, an ER agonist), propyl pyrazole triole (PPT, an ERalpha-selective agonist), diarylpropionitrile (DPN, an ERbeta-selective agonist), or ICI 182,780 (an ER antagonist). Expression of mRNA for Ihh, Dhh, and Ptc1 was dose-dependently downregulated by EE in the uterus of immature rats, mediated by ER as confirmed by coadministration of ICI 182,780. The mRNA expression levels of Ptc1, Gli1, and Coup-TfII were simultaneously downregulated during the period in which the mRNA expression levels of Ihh and Dhh were downregulated in the uterus after administration of EE. PPT downregulated the transcription of Ihh, Dhh, Ptc1, Gli1, and Coup-TfII, indicating that expression of these genes was regulated by the ERalpha-dependent pathway. DPN also downregulated the transcription of Ihh and Dhh, although the effect was weaker than that of PPT, indicating that the regulation of uterine Ihh and Dhh transcription was also affected by the ERbeta-dependent pathway. These results suggest that the expression of Hedgehog genes (Ihh, Dhh) and Hedgehog target genes (Ptc1, Gli1, Coup-TfII) is affected by estrogenic stimuli in the uterus of immature female rats.
Evc is a positive mediator of Ihh-regulated bone growth that localises at the base of chondrocyte cilia.

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Ruiz-Perez, Victor L; Blair, Helen J; Rodriguez-Andres, M Elena; Blanco, Maria Jose; Wilson, Amy; Liu, Yu-Ning; Miles, Colin; Peters, Heiko; Goodship, Judith A

2007-08-01

EVC is a novel protein mutated in the human chondroectodermal dysplasia Ellis-van Creveld syndrome (EvC; OMIM: 225500). We have inactivated Evc in the mouse and show that Evc(-/-) mice develop an EvC-like syndrome, including short ribs, short limbs and dental abnormalities. lacZ driven by the Evc promoter revealed that Evc is expressed in the developing bones and the orofacial region. Antibodies developed against Evc locate the protein at the base of the primary cilium. The growth plate of Evc(-/-) mice shows delayed bone collar formation and advanced maturation of chondrocytes. Indian hedgehog (Ihh) is expressed normally in the growth plates of Evc(-/-) mice, but expression of the Ihh downstream genes Ptch1 and Gli1 was markedly decreased. Recent studies have shown that Smo localises to primary cilia and that Gli3 processing is defective in intraflagellar transport mutants. In vitro studies using Evc(-/-) cells demonstrate that the defect lies downstream of Smo. Chondrocyte cilia are present in Evc(-/-) mice and Gli3 processing appears normal by western blot analysis. We conclude that Evc is an intracellular component of the hedgehog signal transduction pathway that is required for normal transcriptional activation of Ihh target genes.
Gli1-Mediated Regulation of Sox2 Facilitates Self-Renewal of Stem-Like Cells and Confers Resistance to EGFR Inhibitors in Non-Small Cell Lung Cancer.

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Bora-Singhal, Namrata; Perumal, Deepak; Nguyen, Jonathan; Chellappan, Srikumar

2015-07-01

Non-small cell lung cancer (NSCLC) patients have very low survival rates because the current therapeutic strategies are not fully effective. Although EGFR tyrosine kinase inhibitors are effective for NSCLC patients harboring EGFR mutations, patients invariably develop resistance to these agents. Alterations in multiple signaling cascades have been associated with the development of resistance to EGFR inhibitors. Sonic Hedgehog and associated Gli transcription factors play a major role in embryonic development and have recently been found to be reactivated in NSCLC, and elevated Gli1 levels correlate with poor prognosis. The Hedgehog pathway has been implicated in the functions of cancer stem cells, although the underlying molecular mechanisms are not clear. In this context, we demonstrate that Gli1 is a strong regulator of embryonic stem cell transcription factor Sox2. Depletion of Gli1 or inhibition of the Hedgehog signaling significantly abrogated the self-renewal of stem-like side-population cells from NSCLCs as well as vascular mimicry of such cells. Gli1 was found to transcriptionally regulate Sox2 through its promoter region, and Gli1 could be detected on the Sox2 promoter. Inhibition of Hedgehog signaling appeared to work cooperatively with EGFR inhibitors in markedly reducing the viability of NSCLC cells as well as the self-renewal of stem-like cells. Thus, our study demonstrates a cooperative functioning of the EGFR signaling and Hedgehog pathways in governing the stem-like functions of NSCLC cancer stem cells and presents a novel therapeutic strategy to combat NSCLC harboring EGFR mutations. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
A role for smoothened during murine lens and cornea development.

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Janet J Y Choi

Full Text Available Various studies suggest that Hedgehog (Hh signalling plays roles in human and zebrafish ocular development. Recent studies (Kerr et al., Invest Ophthalmol Vis Sci. 2012; 53, 3316-30 showed that conditionally activating Hh signals promotes murine lens epithelial cell proliferation and disrupts fibre differentiation. In this study we examined the expression of the Hh pathway and the requirement for the Smoothened gene in murine lens development. Expression of Hh pathway components in developing lens was examined by RT-PCR, immunofluorescence and in situ hybridisation. The requirement of Smo in lens development was determined by conditional loss-of-function mutations, using LeCre and MLR10 Cre transgenic mice. The phenotype of mutant mice was examined by immunofluorescence for various markers of cell cycle, lens and cornea differentiation. Hh pathway components (Ptch1, Smo, Gli2, Gli3 were detected in lens epithelium from E12.5. Gli2 was particularly localised to mitotic nuclei and, at E13.5, Gli3 exhibited a shift from cytosol to nucleus, suggesting distinct roles for these transcription factors. Conditional deletion of Smo, from ∼E12.5 (MLR10 Cre did not affect ocular development, whereas deletion from ∼E9.5 (LeCre resulted in lens and corneal defects from E14.5. Mutant lenses were smaller and showed normal expression of p57Kip2, c-Maf, E-cadherin and Pax6, reduced expression of FoxE3 and Ptch1 and decreased nuclear Hes1. There was normal G1-S phase but decreased G2-M phase transition at E16.5 and epithelial cell death from E14.5-E16.5. Mutant corneas were thicker due to aberrant migration of Nrp2+ cells from the extraocular mesenchyme, resulting in delayed corneal endothelial but normal epithelial differentiation. These results indicate the Hh pathway is required during a discrete period (E9.5-E12.5 in lens development to regulate lens epithelial cell proliferation, survival and FoxE3 expression. Defective corneal development occurs
Steroidal regulation of Ihh and Gli1 expression in the rat uterus.

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Kubota, Kaiyu; Yamauchi, Nobuhiko; Yamagami, Kazuki; Nishimura, Sho; Gobaru, Takafumi; Yamanaka, Ken-ichi; Wood, Chris; Soh, Tomoki; Takahashi, Masashi; Hattori, Masa-aki

2010-05-01

Ovarian steroid hormones, progesterone (P4), and estradiol (E2) strictly regulate the endometrial tissue remodeling required for successful embryo implantation. Indian hedgehog (Ihh) is up-regulated by P4 and critically mediates uterine receptivity in the mouse. However, the regulation of Ihh expression during the implantation period still remains unclear. The present study was conducted to elucidate the mechanism of the steroidal regulation in the expression of Ihh and Gli1, the mediator of the Ihh pathway. Ihh mRNA was expressed in the rat uterus on 3.5-5.5 days post-coitus (dpc), while Gli1 expression transiently increased at 3.5 dpc but decreased significantly on 5.5 dpc (P Ihh was induced by the implantation-induced E2 treatment in the primed rat uterus. In contrast, expression of Gli1 was significantly decreased by E2 treatment (P = 0.016). In the case of ICI182.780 (ICI) treatment, Ihh expression was eliminated by ICI, whilst Gli1 expression increased. These results suggest that Ihh expression is maintained at a high level until the initiation of implantation, while the expression of Gli1 is decreased just prior to the initiation of implantation depending on the E2 action. This observation aids in the understanding of the Ihh signaling pathway mediating uterine remodeling for implantation.
Transcriptional activation of prostate specific homeobox gene NKX3-1 in subsets of T-cell lymphoblastic leukemia (T-ALL.

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Stefan Nagel

Full Text Available Homeobox genes encode transcription factors impacting key developmental processes including embryogenesis, organogenesis, and cell differentiation. Reflecting their tight transcriptional control, homeobox genes are often embedded in large non-coding, cis-regulatory regions, containing tissue specific elements. In T-cell acute lymphoblastic leukemia (T-ALL homeobox genes are frequently deregulated by chromosomal aberrations, notably translocations adding T-cell specific activatory elements. NKX3-1 is a prostate specific homeobox gene activated in T-ALL patients expressing oncogenic TAL1 or displaying immature T-cell characteristics. After investigating regulation of NKX3-1 in primary cells and cell lines, we report its ectopic expression in T-ALL cells independent of chromosomal rearrangements. Using siRNAs and expression profiling, we exploited NKX3-1 positive T-ALL cell lines as tools to investigate aberrant activatory mechanisms. Our data confirmed NKX3-1 activation by TAL1/GATA3/LMO and identified LYL1 as an alternative activator in immature T-ALL cells devoid of GATA3. Moreover, we showed that NKX3-1 is directly activated by early T-cell homeodomain factor MSX2. These activators were regulated by MLL and/or by IL7-, BMP4- and IGF2-signalling. Finally, we demonstrated homeobox gene SIX6 as a direct leukemic target of NKX3-1 in T-ALL. In conclusion, we identified three major mechanisms of NKX3-1 regulation in T-ALL cell lines which are represented by activators TAL1, LYL1 and MSX2, corresponding to particular T-ALL subtypes described in patients. These results may contribute to the understanding of leukemic transcriptional networks underlying disturbed T-cell differentiation in T-ALL.
The transcription factor ATF3 is upregulated during chondrocyte differentiation and represses cyclin D1 and A gene transcription

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James Claudine G

2006-09-01

Full Text Available Abstract Background Coordinated chondrocyte proliferation and differentiation are required for normal endochondral bone growth. Transcription factors binding to the cyclicAMP response element (CRE are known to regulate these processes. One member of this family, Activating Tanscription Factor 3 (ATF3, is expressed during skeletogenesis and acts as a transcriptional repressor, but the function of this protein in chondrogenesis is unknown. Results Here we demonstrate that Atf3 mRNA levels increase during mouse chondrocyte differentiation in vitro and in vivo. In addition, Atf3 mRNA levels are increased in response to cytochalasin D treatment, an inducer of chondrocyte maturation. This is accompanied by increased Atf3 promoter activity in cytochalasin D-treated chondrocytes. We had shown earlier that transcription of the cell cycle genes cyclin D1 and cyclin A in chondrocytes is dependent on CREs. Here we demonstrate that overexpression of ATF3 in primary mouse chondrocytes results in reduced transcription of both genes, as well as decreased activity of a CRE reporter plasmid. Repression of cyclin A transcription by ATF3 required the CRE in the cyclin A promoter. In parallel, ATF3 overexpression reduces the activity of a SOX9-dependent promoter and increases the activity of a RUNX2-dependent promoter. Conclusion Our data suggest that transcriptional induction of the Atf3 gene in maturing chondrocytes results in down-regulation of cyclin D1 and cyclin A expression as well as activation of RUNX2-dependent transcription. Therefore, ATF3 induction appears to facilitate cell cycle exit and terminal differentiation of chondrocytes.

Hypoxia-Inducible Factor 3 Is an Oxygen-Dependent Transcription Activator and Regulates a Distinct Transcriptional Response to Hypoxia

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Peng Zhang

2014-03-01

Full Text Available Hypoxia-inducible factors (HIFs play key roles in the cellular response to hypoxia. It is widely accepted that whereas HIF-1 and HIF-2 function as transcriptional activators, HIF-3 inhibits HIF-1/2α action. Contrary to this idea, we show that zebrafish Hif-3α has strong transactivation activity. Hif-3α is degraded under normoxia. Mutation of P393, P493, and L503 inhibits this oxygen-dependent degradation. Transcriptomics and chromatin immunoprecipitation analyses identify genes that are regulated by Hif-3α, Hif-1α, or both. Under hypoxia or when overexpressed, Hif-3α binds to its target gene promoters and upregulates their expression. Dominant-negative inhibition and knockdown of Hif-3α abolish hypoxia-induced Hif-3α-promoter binding and gene expression. Hif-3α not only mediates hypoxia-induced growth and developmental retardation but also possesses hypoxia-independent activities. Importantly, transactivation activity is conserved and human HIF-3α upregulates similar genes in human cells. These findings suggest that Hif-3 is an oxygen-dependent transcription factor and activates a distinct transcriptional response to hypoxia.
Glycine transporter GlyT1, but not GlyT2, is expressed in rat dorsal root ganglion--Possible implications for neuropathic pain

NARCIS (Netherlands)

Schlösser, Lukas; Barthel, Franziska; Brandenburger, Timo; Neumann, Elena; Bauer, Inge; Eulenburg, Volker; Werdehausen, Robert; Hermanns, Henning

2015-01-01

Glycinergic inhibitory neurotransmission plays a pivotal role in the development of neuropathic pain. The glycine concentration in the synaptic cleft is controlled by the glycine transporters GlyT1 and GlyT2. GlyT1 is expressed throughout the central nervous system, while GlyT2 is exclusively
MicroRNAs Promote Granule Cell Expansion in the Cerebellum Through Gli2.

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Constantin, Lena; Wainwright, Brandon J

2015-12-01

MicroRNAs (miRNAs) are important regulators of cerebellar function and homeostasis. Their deregulation results in cerebellar neuronal degeneration and spinocerebellar ataxia type 1 and contributes to medulloblastoma. Canonical miRNA processing involves Dicer, which cleaves precursor miRNAs into mature double-stranded RNA duplexes. In order to address the role of miRNAs in cerebellar granule cell precursor development, loxP-flanked exons of Dicer1 were conditionally inactivated using the granule cell precursor-specific Atoh1-Cre recombinase. A reduction of 87% in Dicer1 transcript was achieved in this conditional Dicer knockdown model. Although knockdown resulted in normal survival, mice had disruptions to the cortical layering of the anterior cerebellum, which resulted from the premature differentiation of granule cell precursors in this region during neonatal development. This defect manifested as a thinner external granular layer with ectopic mature granule cells, and a depleted internal granular layer. We found that expression of the activator components of the Hedgehog-Patched pathway, the Gli family of transcription factors, was perturbed in conditional Dicer knockdown mice. We propose that loss of Gli2 mRNA mediated the anterior-restricted defect in conditional Dicer knockdown mice and, as proof of principle, were able to show that miR-106b positively regulated Gli2 mRNA expression. These findings confirm the importance of miRNAs as positive mediators of Hedgehog-Patched signalling during granule cell precursor development.
Molecular Analysis of Gli3, Ihh, Rab23, and Jag1 in a Rabbit Model of Craniosynostosis: Likely Exclusion as the Loci of Origin.

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Gilbert, James R; Taylor, Gwen M; Losee, Joseph E; Mooney, Mark P; Cooper, Gregory M

2018-03-01

Craniosynostosis (CS) involves the premature fusion of one or more cranial sutures. The etiology of CS is complex and mutations in more than 50 distinct genes have been causally linked to the disorder. Many of the genes that have been associated with CS in humans play an essential role in tissue patterning and early craniofacial development. Among these genes are members of the Hedgehog (HH) and Notch signal transduction pathways, including the GLI family member Gli3, Indian Hedgehog ( Ihh), the RAS oncogene family member Rab23, and the Notch ligand JAGGED1 ( Jag1). We have previously described a colony of rabbits with a heritable pattern of coronal suture synostosis, although the genetic basis for synostosis within this model remains unknown. The present study was performed to determine if coding errors in Gli3, Ihh, Rab23, or Jag1 could be causally linked to craniosynostosis in this unique animal model. Sequencing of cDNA templates was performed using samples obtained from wild-type and craniosynostotic rabbits. Several nucleotide polymorphisms were identified in Gli3, Ihh, and Rab23, although these variants failed to segregate by phenotype. No nucleotide polymorphisms were identified in Jag1. These data indicate that the causal locus for heritable craniosynostosis in this rabbit model is not located within the protein coding regions of Gli3, Ihh, Rab23, or Jag1.
Sonic Hedgehog Signaling Drives Proliferation of Synoviocytes in Rheumatoid Arthritis: A Possible Novel Therapeutic Target

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Mingxia Wang

2014-01-01

Full Text Available Sonic hedgehog (Shh signaling controls many aspects of human development, regulates cell growth and differentiation in adult tissues, and is activated in a number of malignancies. Rheumatoid arthritis (RA is characterized by chronic synovitis and pannus formation associated with activation of fibroblast-like synoviocytes (FLS. We investigated whether Shh signaling plays a role in the proliferation of FLS in RA. Expression of Shh signaling related components (Shh, Ptch1, Smo, and Gli1 in RA synovial tissues was examined by immunohistochemistry (IHC and in FLS by IHC, immunofluorescence (IF, quantitative RT-PCR, and western blotting. Expression of Shh, Smo, and Gli1 in RA synovial tissue was higher than that in control tissue (P<0.05. Cyclopamine (a specific inhibitor of Shh signaling decreased mRNA expression of Shh, Ptch1, Smo, and Gli1 in cultured RA FLS, Shh, and Smo protein expression, and significantly decreased FLS proliferation. Flow cytometry analysis suggested that cyclopamine treatment resulted in cell cycle arrest of FLS in G1 phase. Our data show that Shh signaling is activated in synovium of RA patients in vivo and in cultured FLS form RA patients in vitro, suggesting a role in the proliferation of FLS in RA. It may therefore be a novel therapeutic target in RA.
Somatic mosaicism containing double mutations in PTCH1 revealed by generation of induced pluripotent stem cells from nevoid basal cell carcinoma syndrome.

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Ikemoto, Yu; Takayama, Yoshinaga; Fujii, Katsunori; Masuda, Mokuri; Kato, Chise; Hatsuse, Hiromi; Fujitani, Kazuko; Nagao, Kazuaki; Kameyama, Kohzoh; Ikehara, Hajime; Toyoda, Masashi; Umezawa, Akihiro; Miyashita, Toshiyuki

2017-08-01

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterised by developmental defects and tumorigenesis, such as medulloblastomas and basal cell carcinomas, caused by mutations of the patched-1 ( PTCH1 ) gene. In this article, we seek to demonstrate a mosaicism containing double mutations in PTCH1 in an individual with NBCCS. A de novo germline mutation of PTCH1 (c.272delG) was detected in a 31-year-old woman with NBCCS. Gene analysis of two out of four induced pluripotent stem cell (iPSC) clones established from the patient unexpectedly revealed an additional mutation, c.274delT. Deep sequencing confirmed a low-prevalence somatic mutation (5.5%-15.6% depending on the tissue) identical to the one found in iPSC clones. This is the first case of mosaicism unequivocally demonstrated in NBCCS. Furthermore, the mosaicism is unique in that the patient carries one normal and two mutant alleles. Because these mutations are located in close proximity, reversion error is likely to be involved in this event rather than a spontaneous mutation. In addition, this study indicates that gene analysis of iPSC clones can contribute to the detection of mosaicism containing a minor population carrying a second mutation. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.
The Effect of the Arg389Gly Beta-1 Adrenoceptor Polymorphism on Plasma Renin Activity and Heart Rate and the Genotype-Dependent Response to Metoprolol Treatment

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Petersen, Morten; Andersen, Jon T; Jimenez-Solem, Espen

2012-01-01

A gene-drug interaction has been indicated between beta-1 selective beta-blockers and the Arg389Gly polymorphism (rs1801253) in the adrenergic beta-1 receptor gene (ADRB1). We studied the effect of the ADRB1 Arg389Gly polymorphism on plasma renin activity (PRA) and heart rate (HR) and the genotype...
The sequential action of a dipeptidase and a beta-lyase is required for the release of the human body odorant 3-methyl-3-sulfanylhexan-1-ol from a secreted Cys-Gly-(S) conjugate by Corynebacteria.

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Emter, Roger; Natsch, Andreas

2008-07-25

Human axillary odor is formed by the action of Corynebacteria on odorless axilla secretions. Sulfanylalkanols, 3-methyl-3-sulfanylhexan-1-ol in particular, form one key class of the odoriferous compounds. A conjugate with the dipeptide Cys-Gly has been reported as the secreted precursor for 3-methyl-3-sulfanylhexan-1-ol. Here, we confirm the Cys-Gly-(S) conjugate as the major precursor of this odorant, with lower levels of the Cys-(S) conjugate being present in axilla secretions. The enzymatic release of 3-methyl-3-sulfanylhexan-1-ol from the Cys-Gly-(S) conjugate by the axilla isolate Corynebacterium Ax20 was thus investigated. Cellular extracts of Ax20 released 3-methyl-3-sulfanylhexan-1-ol from the Cys-Gly-(S) conjugate and from the Cys-(S) conjugate, whereas the previously isolated C-S lyase of this bacterial strain was only able to cleave the Cys-(S) conjugate. o-Phenanthroline blocked the release from the Cys-Gly-(S) conjugate but did not affect cleavage of the Cys-(S) conjugate, indicating that in a first step, a metal-dependent dipeptidase hydrolyzes the Cys-Gly bond. This enzyme was purified by four chromatographic steps and gel electrophoresis, and the partial amino acid sequence was determined. The corresponding gene was cloned and expressed in Escherichia coli. It codes for a novel dipeptidase with a high affinity toward the Cys-Gly-(S) conjugate of 3-methyl-3-sulfanylhexan-1-ol. Co-incubating either the synthetic Cys-Gly-(S) conjugate or fresh axilla secretions with both the C-S lyase and the novel dipeptidase did release 3-methyl-3-sulfanylhexan-1-ol, proving that the sequential action of these two enzymes from the skin bacterium Corynebacterium Ax20 does release the odorant from the key secreted precursor.
Hepatitis C virus nonstructural protein-5A activates sterol regulatory element-binding protein-1c through transcription factor Sp1

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Xiang, Zhonghua; Qiao, Ling; Zhou, Yan [Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3 (Canada); Babiuk, Lorne A. [University of Alberta, Edmonton, Alberta (Canada); Liu, Qiang, E-mail: qiang.liu@usask.ca [Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3 (Canada)

2010-11-19

Research highlights: {yields} A chimeric subgenomic HCV replicon expresses HCV-3a NS5A in an HCV-1b backbone. {yields} HCV-3a NS5A increases mature SREBP-1c protein level. {yields} HCV-3a NS5A activates SREBP-1c transcription. {yields} Domain II of HCV-3a NS5A is more effective in SREBP-1c promoter activation. {yields} Transcription factor Sp1 is required for SREBP-1c activation by HCV-3a NS5A. -- Abstract: Steatosis is an important clinical manifestation of hepatitis C virus (HCV) infection. The molecular mechanisms of HCV-associated steatosis are not well understood. Sterol regulatory element-binding protein-1c (SREBP-1c) is a key transcription factor which activates the transcription of lipogenic genes. Here we showed that the nuclear, mature SREBP-1c level increases in the nucleus of replicon cells expressing HCV-3a nonstructural protein-5A (NS5A). We further showed that HCV-3a NS5A up-regulates SREBP-1c transcription. Additional analysis showed that transcriptional factor Sp1 is involved in SREBP-1c activation by HCV-3a NS5A because inhibition of Sp1 activity by mithramycin A or a dominant-negative Sp1 construct abrogated SREBP-1c promoter activation by HCV-3a NS5A. In addition, chromatin immunoprecipitation (ChIP) assay demonstrated enhanced binding of Sp1 on the SREBP-1c promoter in HCV-3a NS5A replicon cells. These results showed that HCV-3a NS5A activates SREBP-1c transcription through Sp1. Taken together, our results suggest that HCV-3a NS5A is a contributing factor for steatosis caused by HCV-3a infection.
Hepatitis C virus nonstructural protein-5A activates sterol regulatory element-binding protein-1c through transcription factor Sp1

International Nuclear Information System (INIS)

Xiang, Zhonghua; Qiao, Ling; Zhou, Yan; Babiuk, Lorne A.; Liu, Qiang

2010-01-01

Research highlights: → A chimeric subgenomic HCV replicon expresses HCV-3a NS5A in an HCV-1b backbone. → HCV-3a NS5A increases mature SREBP-1c protein level. → HCV-3a NS5A activates SREBP-1c transcription. → Domain II of HCV-3a NS5A is more effective in SREBP-1c promoter activation. → Transcription factor Sp1 is required for SREBP-1c activation by HCV-3a NS5A. -- Abstract: Steatosis is an important clinical manifestation of hepatitis C virus (HCV) infection. The molecular mechanisms of HCV-associated steatosis are not well understood. Sterol regulatory element-binding protein-1c (SREBP-1c) is a key transcription factor which activates the transcription of lipogenic genes. Here we showed that the nuclear, mature SREBP-1c level increases in the nucleus of replicon cells expressing HCV-3a nonstructural protein-5A (NS5A). We further showed that HCV-3a NS5A up-regulates SREBP-1c transcription. Additional analysis showed that transcriptional factor Sp1 is involved in SREBP-1c activation by HCV-3a NS5A because inhibition of Sp1 activity by mithramycin A or a dominant-negative Sp1 construct abrogated SREBP-1c promoter activation by HCV-3a NS5A. In addition, chromatin immunoprecipitation (ChIP) assay demonstrated enhanced binding of Sp1 on the SREBP-1c promoter in HCV-3a NS5A replicon cells. These results showed that HCV-3a NS5A activates SREBP-1c transcription through Sp1. Taken together, our results suggest that HCV-3a NS5A is a contributing factor for steatosis caused by HCV-3a infection.
PKC-Dependent GlyT1 Ubiquitination Occurs Independent of Phosphorylation: Inespecificity in Lysine Selection for Ubiquitination.

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Susana P Barrera

Full Text Available Neurotransmitter transporter ubiquitination is emerging as the main mechanism for endocytosis and sorting of cargo into lysosomes. In this study, we demonstrate PKC-dependent ubiquitination of three different isoforms of the glycine transporter 1 (GlyT1. Incubation of cells expressing transporter with the PKC activator phorbol ester induced a dramatic, time-dependent increase in GlyT1 ubiquitination, followed by accumulation of GlyT1 in EEA1 positive early endosomes. This occurred via a mechanism that was abolished by inhibition of PKC. GlyT1 endocytosis was confirmed in both retinal sections and primary cultures of mouse amacrine neurons. Replacement of only all lysines in the N-and C-termini to arginines prevented ubiquitination and endocytosis, displaying redundancy in the mechanism of ubiquitination. Interestingly, a 40-50% reduction in glycine uptake was detected in phorbol-ester stimulated cells expressing the WT-GlyT1, whereas no significant change was for the mutant protein, demonstrating that endocytosis participates in the reduction of uptake. Consistent with previous findings for the dopamine transporter DAT, ubiquitination of GlyT1 tails functions as sorting signal to deliver transporter into the lysosome and removal of ubiquitination sites dramatically attenuated the rate of GlyT1 degradation. Finally, we showed for the first time that PKC-dependent GlyT1 phosphorylation was not affected by removal of ubiquitination sites, suggesting separate PKC-dependent signaling events for these posttranslational modifications.
THRAP3 interacts with and inhibits the transcriptional activity of SOX9 during chondrogenesis.

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Sono, Takashi; Akiyama, Haruhiko; Miura, Shigenori; Deng, Jian Min; Shukunami, Chisa; Hiraki, Yuji; Tsushima, Yu; Azuma, Yoshiaki; Behringer, Richard R; Matsuda, Shuichi

2018-07-01

Sex-determining region Y (Sry)-box (Sox)9 is required for chondrogenesis as a transcriptional activator of genes related to chondrocyte proliferation, differentiation, and cartilage-specific extracellular matrix. Although there have been studies investigating the Sox9-dependent transcriptional complexes, not all their components have been identified. In the present study, we demonstrated that thyroid hormone receptor-associated protein (THRAP)3 is a component of a SOX9 transcriptional complex by liquid chromatography mass spectrometric analysis of FLAG-tagged Sox9-binding proteins purified from FLAG-HA-tagged Sox9 knock-in mice. Thrap3 knockdown in ATDC5 chondrogenic cells increased the expression of Collagen type II alpha 1 chain (Col2a1) without affecting Sox9 expression. THRAP3 and SOX9 overexpression reduced Col2a1 levels to a greater degree than overexpression of SOX9 alone. The negative regulation of SOX9 transcriptional activity by THRAP3 was mediated by interaction between the proline-, glutamine-, and serine-rich domain of SOX9 and the innominate domain of THRAP3. These results indicate that THRAP3 negatively regulates SOX9 transcriptional activity as a cofactor of a SOX9 transcriptional complex during chondrogenesis.
Inflammation and Gli2 suppress gastrin gene expression in a murine model of antral hyperplasia.

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Milena Saqui-Salces

Full Text Available Chronic inflammation in the stomach can lead to gastric cancer. We previously reported that gastrin-deficient (Gast⁻/⁻ mice develop bacterial overgrowth, inflammatory infiltrate, increased Il-1β expression, antral hyperplasia and eventually antral tumors. Since Hedgehog (Hh signaling is active in gastric cancers but its role in precursor lesions is poorly understood, we examined the role of inflammation and Hh signaling in antral hyperplasia. LacZ reporter mice for Sonic hedgehog (Shh, Gli1, and Gli2 expression bred onto the Gast⁻/⁻ background revealed reduced Shh and Gli1 expression in the antra compared to wild type controls (WT. Gli2 expression in the Gast⁻/⁻ corpus was unchanged. However in the hyperplastic Gast⁻/⁻ antra, Gli2 expression increased in both the mesenchyme and epithelium, whereas expression in WT mice remained exclusively mesenchymal. These observations suggested that Gli2 is differentially regulated in the hyperplastic Gast⁻/⁻ antrum versus the corpus and by a Shh ligand-independent mechanism. Moreover, the proinflammatory cytokines Il-1β and Il-11, which promote gastric epithelial proliferation, were increased in the Gast⁻/⁻ stomach along with Infγ. To test if inflammation could account for elevated epithelial Gli2 expression in the Gast⁻/⁻ antra, the human gastric cell line AGS was treated with IL-1β and was found to increase GLI2 but decrease GLI1 levels. IL-1β also repressed human GAST gene expression. Indeed, GLI2 but not GLI1 or GLI3 expression repressed gastrin luciferase reporter activity by ∼50 percent. Moreover, chromatin immunoprecipitation of GLI2 in AGS cells confirmed that GLI2 directly binds to the GAST promoter. Using a mouse model of constitutively active epithelial GLI2 expression, we found that activated GLI2 repressed Gast expression but induced Il-1β gene expression and proliferation in the gastric antrum, along with a reduction of the number of G-cells. In summary
The Inflammatory Transcription Factors NFκB, STAT1 and STAT3 Drive Age-Associated Transcriptional Changes in the Human Kidney

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O’Brown, Zach K.; Van Nostrand, Eric L.; Higgins, John P.; Kim, Stuart K.

2015-01-01

Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. To identify potential regulators of kidney aging, we compared age-associated transcriptional changes in the human kidney with genome-wide maps of transcription factor occupancy from ChIP-seq datasets in human cells. The strongest candidates were the inflammation-associated transcription factors NFκB, STAT1 and STAT3, the activities of which increase with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator), IFNγ (a STAT1 activator), or TNFα (an NFκB activator) recapitulated age-associated gene expression changes. We show that common DNA variants in RELA and NFKB1, the two genes encoding subunits of the NFκB transcription factor, associate with kidney function and chronic kidney disease in gene association studies, providing the first evidence that genetic variation in NFκB contributes to renal aging phenotypes. Our results suggest that NFκB, STAT1 and STAT3 underlie transcriptional changes and chronic inflammation in the aging human kidney. PMID:26678048
Sp1 and Sp3 Are the Transcription Activators of Human ek1 Promoter in TSA-Treated Human Colon Carcinoma Cells.

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Kuan, Chee Sian; See Too, Wei Cun; Few, Ling Ling

2016-01-01

Ethanolamine kinase (EK) catalyzes the phosphorylation of ethanolamine, the first step in the CDP-ethanolamine pathway for the biosynthesis of phosphatidylethanolamine (PE). Human EK exists as EK1, EK2α and EK2β isoforms, encoded by two separate genes, named ek1 and ek2. EK activity is stimulated by carcinogens and oncogenes, suggesting the involvement of EK in carcinogenesis. Currently, little is known about EK transcriptional regulation by endogenous or exogenous signals, and the ek gene promoter has never been studied. In this report, we mapped the important regulatory regions in the human ek1 promoter. 5' deletion analysis and site-directed mutagenesis identified a Sp site at position (-40/-31) that was essential for the basal transcription of this gene. Treatment of HCT116 cells with trichostatin A (TSA), a histone deacetylase inhibitor, significantly upregulated the ek1 promoter activity through the Sp(-40/-31) site and increased the endogenous expression of ek1. Chromatin immunoprecipitation assay revealed that TSA increased the binding of Sp1, Sp3 and RNA polymerase II to the ek1 promoter in HCT116 cells. The effect of TSA on ek1 promoter activity was cell-line specific as TSA treatment did not affect ek1 promoter activity in HepG2 cells. In conclusion, we showed that Sp1 and Sp3 are not only essential for the basal transcription of the ek1 gene, their accessibility to the target site on the ek1 promoter is regulated by histone protein modification in a cell line dependent manner.
Gli as a novel therapeutic target in malignant pleural mesothelioma.

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Hui Li

Full Text Available Malignant pleural mesothelioma (MPM is a highly aggressive tumor with poor prognosis. Current treatment is rarely curative, thus novel meaningful therapies are urgently needed. Inhibition of Hedgehog (Hh signaling at the cell membrane level in several cancers has shown anti-cancer activity in recent clinical studies. Evidence of Hh-independent Gli activation suggests Gli as a more potent therapeutic target. The current study is aimed to evaluate the potential of Gli as a therapeutic target to treat MPM. The expression profiles of Gli factors and other Hh signaling components were characterized in 46 MPM patient tissue samples by RT-PCR and immunohistochemistry. Cultured cell lines were employed to investigate the requirement of Gli activation in tumor cell growth by inhibiting Gli through siRNA or a novel small molecule Gli inhibitor (Gli-I. A xenograft model was used to evaluate Gli-I in vivo. In addition, a side by side comparison between Gli and Smoothened (Smo inhibition was conducted in vitro using siRNA and small molecule inhibitors. Our study reported aberrant Gli1 and Gli2 activation in a large majority of tissues. Inhibition of Gli by siRNAs or Gli-I suppressed cell growth dramatically both in vitro and in vivo. Inhibition of Gli exhibited better cytotoxicity than that of Smo by siRNA and small molecule inhibitors vismodegib and cyclopamine. Combination of Gli-I and pemetrexed, as well as Gli-I and vismodegib demonstrated synergistic effects in suppression of MPM proliferation in vitro. In summary, Gli activation plays a critical role in MPM. Inhibition of Gli function holds strong potential to become a novel, clinically effective approach to treat MPM.
Gli2a protein localization reveals a role for Iguana/DZIP1 in primary ciliogenesis and a dependence of Hedgehog signal transduction on primary cilia in the zebrafish

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van Eeden Freek

2010-04-01

Full Text Available Abstract Background In mammalian cells, the integrity of the primary cilium is critical for proper regulation of the Hedgehog (Hh signal transduction pathway. Whether or not this dependence on the primary cilium is a universal feature of vertebrate Hedgehog signalling has remained contentious due, in part, to the apparent divergence of the intracellular transduction pathway between mammals and teleost fish. Results Here, using a functional Gli2-GFP fusion protein, we show that, as in mammals, the Gli2 transcription factor localizes to the primary cilia of cells in the zebrafish embryo and that this localization is modulated by the activity of the Hh pathway. Moreover, we show that the Igu/DZIP1protein, previously implicated in the modulation of Gli activity in zebrafish, also localizes to the primary cilium and is required for its proper formation. Conclusion Our findings demonstrate a conserved role of the primary cilium in mediating Hedgehog signalling activity across the vertebrate phylum and validate the use of the zebrafish as a representative model for the in vivo analysis of vertebrate Hedgehog signalling.
GLI3 Links Environmental Arsenic Exposure and Human Fetal Growth

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Emily F. Winterbottom

2015-06-01

Full Text Available Although considerable evidence suggests that in utero arsenic exposure affects children's health, these data are mainly from areas of the world where groundwater arsenic levels far exceed the World Health Organization limit of 10 μg/L. We, and others, have found that more common levels of in utero arsenic exposure may also impact children's health. However, the underlying molecular mechanisms are poorly understood. To address this issue, we analyzed the expression of key developmental genes in fetal placenta in a birth cohort of women using unregulated water supplies in a US region with elevated groundwater arsenic. We identified several genes whose expression associated with maternal arsenic exposure in a fetal sex-specific manner. In particular, expression of the HEDGEHOG pathway component, GLI3, in female placentae was both negatively associated with arsenic exposure and positively associated with infant birth weight. This suggests that modulation of GLI3 in the fetal placenta, and perhaps in other fetal tissues, contributes to arsenic's detrimental effects on fetal growth. We showed previously that arsenic-exposed NIH3T3 cells have reduced GLI3 repressor protein. Together, these studies identify GLI3 as a key signaling node that is affected by arsenic, mediating a subset of its effects on developmental signaling and fetal health.
Design and Synthesis of Novel and Selective Glycine Transporter-1 (GlyT1) Inhibitors with Memory Enhancing Properties.

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Santora, Vincent J; Almos, Theresa A; Barido, Richard; Basinger, Jillian; Bellows, Chris L; Bookser, Brett Carder; Breitenbucher, J Guy; Broadbent, Nicola J; Cabebe, Clifford; Chai, Chih-Kun; Chen, Mi; Chow, Stephine; Chung, De Michael; Crickard, Lindsay; Danks, Anne M; Freestone, Graeme; Gitnick, Dany; Gupta, Varsha; Hoffmaster, Christine; Hudson, Andrew R; Kaplan, Alan P; Kennedy, Michael R; Lee, Dong; Limberis, James; Ly, Kiev; Mak, Chi Ching; Masatsugu, Brittany; Morse, Andrew C; Na, Jim; Neul, David; Nikpur, John; Peters, Marco; Petroski, Robert E; Renick, Joel; Sebring, Kristen; Sevidal, Samantha; Tabatabaei, Ali; Wen, Jenny; Yan, Yingzhuo; Yoder, Zachary W; Zook, Douglas

2018-06-11

We report here the identification and optimization of a novel series of potent GlyT1 inhibitors. A ligand design campaign that utilized known GlyT1 inhibitors as starting points led to the identification of a novel series of pyrrolo[3,4-c]pyrazoles amides (21-50) with good in vitro potency. Subsequent optimization of physicochemical and in vitro ADME properties produced several compounds with promising pharmacokinetic profiles. In vivo inhibition of GlyT1 was demonstrated for select compounds within this series by measuring the elevation of glycine in the cerebrospinal fluid (CSF) of rats after a single oral dosing of 10 mg/kg. Ultimately, an optimized lead, compound 46, demonstrated in vivo efficacy in a rat Novel Object Recognition (NOR) assay after oral dosing at 0.1, 1, and 3 mg/kg.
Peptide analysis as amino alcohols by gas chromatography-mass spectrometry. Application to hyperoligopeptiduria. Detection of Gly-3Hyp-4Hyp and Gly-Pro-4Hyp-Gly.

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Steiner, W; Niederwieser, A

1979-03-15

A method for the qualitative analysis of oligopeptides in human urine in cases of peptiduria is described. After sample precleaning on a strongly acidic ion exchanger, the trifluoroacetyl/methyl esters were formed and the peptide derivatives were transformed into trifluoroethyl oligoamino alcohols according to Nau and Biemann. It was found that oligoamino alcohols could be isolated selectively on a weakly acidic ion exchanger. The O-trimethylsilylated trifluoroethyl oligoamino alcohols were separated on a SE-30 glass capillary column and analyzed by computer-assisted gas chromatography-mass spectrometry. In order to increase specificity and to facilitate mass spectrometric interpretation, aliquots of the sample were reduced separately with lithium-aluminium deuteride and hydride. Each peptide gave a pair of derivatives with characteristic mass differences of the ions, namely 2 mass units per reduced oxo group (deuterium-hydrogen-labelling of oxo groups by reduction). Correct identification is assumed only if both mass spectral patterns fit the theory. Sample volumes of 5--100 ml of urine are needed. About six samples can be derivatized per week. Three cases with suspected peptiduria were investigated and the following peptides were found: Gly-Pro-4Hyp-Gly; Gly-Pro-4Hyp; Gly-Hyp-Hyp (postulated isomer Gly-3Hyp-4Hyp); Pro-4Hyp and Gly-Pro. With exception of the tetrapeptide, these compounds could be detected also in the urine of a healthy child.

Sox2, Tlx, Gli3, and Her9 converge on Rx2 to define retinal stem cells in vivo

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Reinhardt, Robert; Centanin, Lázaro; Tavhelidse, Tinatini; Inoue, Daigo; Wittbrodt, Beate; Concordet, Jean-Paul; Martinez-Morales, Juan Ramón; Wittbrodt, Joachim

2015-01-01

Transcriptional networks defining stemness in adult neural stem cells (NSCs) are largely unknown. We used the proximal cis-regulatory element (pCRE) of the retina-specific homeobox gene 2 (rx2) to address such a network. Lineage analysis in the fish retina identified rx2 as marker for multipotent NSCs. rx2-positive cells located in the peripheral ciliary marginal zone behave as stem cells for the neuroretina, or the retinal pigmented epithelium. We identified upstream regulators of rx2 interrogating the rx2 pCRE in a trans-regulation screen and focused on four TFs (Sox2, Tlx, Gli3, and Her9) activating or repressing rx2 expression. We demonstrated direct interaction of the rx2 pCRE with the four factors in vitro and in vivo. By conditional mosaic gain- and loss-of-function analyses, we validated the activity of those factors on regulating rx2 transcription and consequently modulating neuroretinal and RPE stem cell features. This becomes obvious by the rx2-mutant phenotypes that together with the data presented above identify rx2 as a transcriptional hub balancing stemness of neuroretinal and RPE stem cells in the adult fish retina. PMID:25908840
Surface-enhanced Raman spectrum of Gly-Gly adsorbed on the silver colloidal surface

Science.gov (United States)

Xiaojuan, Yuan; Huaimin, Gu; Jiwei, Wu

2010-08-01

Raman and SERS spectra of homodipeptide Gly-Gly and Gly were recorded and compared in this paper, and band assignment for the functional groups contained in these molecules was analyzed in detail. Time-dependent and pH-dependent SERS spectra of Gly-Gly molecule adsorbed on nano-colloidal silver surface were also studied. The time-dependent SERS spectra of Gly-Gly are characterized by the increase in intensity of bands primarily representing the vibrational signatures emanating from the amino and amide moiety of Gly-Gly molecule. It is found that the adsorption style of Gly-Gly on the silver colloid changes as time goes on; at 5 min after adding the sample to the silver colloid, Gly-Gly adsorbs on silver surface firstly through the carboxylate, amino and amide groups, and then the carboxylate group is far away from the silver surface at 10 min to 3 days. The SERS variation of Gly-Gly with the change of pH suggests that the adsorption style is pH-dependent, the different adsorption behavior of the Gly-Gly occurs on silver surface at different pH values.
New insights into genotype–phenotype correlation for GLI3 mutations

OpenAIRE

Démurger, Florence; Ichkou, Amale; Mougou-Zerelli, Soumaya; Le Merrer, Martine; Goudefroye, Géraldine; Delezoide, Anne-Lise; Quélin, Chloé; Manouvrier, Sylvie; Baujat, Geneviève; Fradin, Mélanie; Pasquier, Laurent; Megarbané, André; Faivre, Laurence; Baumann, Clarisse; Nampoothiri, Sheela

2014-01-01

The phenotypic spectrum of GLI3 mutations includes autosomal dominant Greig cephalopolysyndactyly syndrome (GCPS) and Pallister–Hall syndrome (PHS). PHS was first described as a lethal condition associating hypothalamic hamartoma, postaxial or central polydactyly, anal atresia and bifid epiglottis. Typical GCPS combines polysyndactyly of hands and feet and craniofacial features. Genotype–phenotype correlations have been found both for the location and the nature of GLI3 mutations, highlightin...
Basal transcription of APOBEC3G is regulated by USF1 gene in hepatocyte

Energy Technology Data Exchange (ETDEWEB)

Zeng, Yanli [Department of Infectious Diseases, Zhengzhou University People' s Hospital (Henan Provincial People' s Hospital), Zhengzhou, 450003 (China); Li, Hui [The Central Hospital of Wuhan, Tongji Medical College Huazhong University of Science Technology, Wuhan, 430000 (China); Zhang, Xiaoju [Department of Respiratory Medicine, Zhengzhou University People' s Hospital (Henan Provincial People' s Hospital), Zhengzhou, 450003 (China); Shang, Jia [Department of Infectious Diseases, Zhengzhou University People' s Hospital (Henan Provincial People' s Hospital), Zhengzhou, 450003 (China); Kang, Yi, E-mail: kykangyi@163.com [Department of Infectious Diseases, Zhengzhou University People' s Hospital (Henan Provincial People' s Hospital), Zhengzhou, 450003 (China)

2016-01-29

Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G, A3G) exert antiviral defense as an important factor of innate immunity. A variety of cytokines such as IFN-γ,IL2,IL15,IL7 could induce the transcription of A3G. However, the regulation of other nuclear factor on the transcription of A3G have not been reported at the present. To gain new insights into the transcriptional regulation of this restriction factor, we cloned and characterized the promoter region of A3G and investigate the modulation of USF1 gene on the transcription of A3G. We identified a 232 bp region that was sufficient to regulate the activity of full promoter. Transcriptional start sites (TSS) were identified by the luciferase reporter assays of plasmids containing full or shorter fragments of the A3G promoter. The results demonstrated that the core promoter of A3G is located within the region -159/-84 relative to the TSS. Transcriptional activity of A3G core promoter regulated by USF1 was dependent on an E-box (located at position -91/-86 relative to the major TSS) and was abolished after mutation of this DNA element. USF1 gene can take part in basal transcription regulation of the human A3G gene in hepatocyte, and the identified E-box represented a binding site for the USF1. - Highlights: • The core promoter of A3G is located within the region −159/−84 relative to the TSS. • Transcriptional activity of A3G core promoter regulated by USF1 was dependent on an E-box (located at position −91/−86 relative to the major TSS). • USF1 gene can take part in basal transcription regulation of the human A3G gene in hepatocyte.
Basal transcription of APOBEC3G is regulated by USF1 gene in hepatocyte

International Nuclear Information System (INIS)

Zeng, Yanli; Li, Hui; Zhang, Xiaoju; Shang, Jia; Kang, Yi

2016-01-01

Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G, A3G) exert antiviral defense as an important factor of innate immunity. A variety of cytokines such as IFN-γ,IL2,IL15,IL7 could induce the transcription of A3G. However, the regulation of other nuclear factor on the transcription of A3G have not been reported at the present. To gain new insights into the transcriptional regulation of this restriction factor, we cloned and characterized the promoter region of A3G and investigate the modulation of USF1 gene on the transcription of A3G. We identified a 232 bp region that was sufficient to regulate the activity of full promoter. Transcriptional start sites (TSS) were identified by the luciferase reporter assays of plasmids containing full or shorter fragments of the A3G promoter. The results demonstrated that the core promoter of A3G is located within the region -159/-84 relative to the TSS. Transcriptional activity of A3G core promoter regulated by USF1 was dependent on an E-box (located at position -91/-86 relative to the major TSS) and was abolished after mutation of this DNA element. USF1 gene can take part in basal transcription regulation of the human A3G gene in hepatocyte, and the identified E-box represented a binding site for the USF1. - Highlights: • The core promoter of A3G is located within the region −159/−84 relative to the TSS. • Transcriptional activity of A3G core promoter regulated by USF1 was dependent on an E-box (located at position −91/−86 relative to the major TSS). • USF1 gene can take part in basal transcription regulation of the human A3G gene in hepatocyte.
E-cadherin is transcriptionally activated via suppression of ZEB1 transcriptional repressor by small RNA-mediated gene silencing.

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Minami Mazda

Full Text Available RNA activation has been reported to be induced by small interfering RNAs (siRNAs that act on the promoters of several genes containing E-cadherin. In this study, we present an alternative mechanism of E-cadherin activation in human PC-3 cells by siRNAs previously reported to possess perfect-complementary sequences to E-cadherin promoter. We found that activation of E-cadherin can be also induced via suppression of ZEB1, which is a transcriptional repressor of E-cadherin, by seed-dependent silencing mechanism of these siRNAs. The functional seed-complementary sites of the siRNAs were found in the coding region in addition to the 3' untranslated region of ZEB1 mRNA. Promoter analyses indicated that E-boxes, which are ZEB1-binding sites, in the upstream promoter region are indispensable for E-cadherin transcription by the siRNAs. Thus, the results caution against ignoring siRNA seed-dependent silencing effects in genome-wide transcriptional regulation. In addition, members of miR-302/372/373/520 family, which have the same seed sequences with one of the siRNAs containing perfect-complementarity to E-cadherin promoter, are also found to activate E-cadherin transcription. Thus, E-cadherin could be upregulated by the suppression of ZEB1 transcriptional repressor by miRNAs in vivo.
Sonic hedgehog (SHH) and glioblastoma-2 (Gli-2) expressions are associated with poor jaundice-free survival in biliary atresia.

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Jung, Hae Yoen; Jing, Jin; Lee, Kyoung Bun; Jang, Ja-June

2015-03-01

Biliary atresia (BA) causes biliary obstruction in neonates. Although the Kasai operation can successfully treat certain BA cases, many patients exhibit recurrent jaundice and secondary biliary cirrhosis requiring liver transplantation. Consequently, studies of the prognostic factors of the Kasai operation are needed. Accordingly, sonic hedgehog (SHH) pathway expression at the extrahepatic bile duct (EHBD), an important bile duct repair mechanism, will be investigated via immunohistochemistry in patients with BA to examine the association with post-Kasai operation prognosis. Fifty-seven EHBD specimens were obtained during Kasai operations from 1992 to 2009. The SHH, patched (PTCH), and glioblastoma-2 (Gli-2) immunohistochemical staining results were analyzed quantitatively. Overall, 57.9% of patients had bile flow normalization after the Kasai operation; 43.1% did not. High preoperative serum total bilirubin, direct bilirubin, and aspartate aminotransferase levels were associated with sustained jaundice post-Kasai operation, as was an age ≥65days at the time of surgery (all pjaundice relapse. Strong Gli-2 and SHH expression in the EHBD might be a poor prognostic factor in Kasai operation-treated patients with BA. Copyright © 2015 Elsevier Inc. All rights reserved.
Structure-activity relationship of linear peptide Bu-His-DPhe-Arg-Trp-Gly-NH(2) at the human melanocortin-1 and -4 receptors: histidine substitution.

Science.gov (United States)

Cheung, Adrian Wai-Hing; Danho, Waleed; Swistok, Joseph; Qi, Lida; Kurylko, Grazyna; Rowan, Karen; Yeon, Mitch; Franco, Lucia; Chu, Xin-Jie; Chen, Li; Yagaloff, Keith

2003-01-06

Systematic substitution of His(6) residue using non-selective hMC4R pentapeptide agonist (Bu-His(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-NH(2)) as the template led to the identification of Bu-Atc(6)(2-aminotetraline-2-carboxylic acid)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-NH(2) which showed moderate selectivity towards hMC4R over hMC1R. Further SAR studies resulted in the discovery of Penta-5-BrAtc(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-NH(2) and Penta-5-Me(2)NAtc(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-NH(2) which are potent hMC4R agonists and are inactive in hMC1R, hMC3R and hMC5R agonist assays.
Sox2, Tlx, Gli3, and Her9 converge on Rx2 to define retinal stem cells in vivo.

Science.gov (United States)

Reinhardt, Robert; Centanin, Lázaro; Tavhelidse, Tinatini; Inoue, Daigo; Wittbrodt, Beate; Concordet, Jean-Paul; Martinez-Morales, Juan Ramón; Wittbrodt, Joachim

2015-06-03

Transcriptional networks defining stemness in adult neural stem cells (NSCs) are largely unknown. We used the proximal cis-regulatory element (pCRE) of the retina-specific homeobox gene 2 (rx2) to address such a network. Lineage analysis in the fish retina identified rx2 as marker for multipotent NSCs. rx2-positive cells located in the peripheral ciliary marginal zone behave as stem cells for the neuroretina, or the retinal pigmented epithelium. We identified upstream regulators of rx2 interrogating the rx2 pCRE in a trans-regulation screen and focused on four TFs (Sox2, Tlx, Gli3, and Her9) activating or repressing rx2 expression. We demonstrated direct interaction of the rx2 pCRE with the four factors in vitro and in vivo. By conditional mosaic gain- and loss-of-function analyses, we validated the activity of those factors on regulating rx2 transcription and consequently modulating neuroretinal and RPE stem cell features. This becomes obvious by the rx2-mutant phenotypes that together with the data presented above identify rx2 as a transcriptional hub balancing stemness of neuroretinal and RPE stem cells in the adult fish retina. © 2015 The Authors. Published under the terms of the CC BY NC ND 4.0 license.
DOT1L and H3K79 Methylation in Transcription and Genomic Stability.

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Wood, Katherine; Tellier, Michael; Murphy, Shona

2018-02-27

The organization of eukaryotic genomes into chromatin provides challenges for the cell to accomplish basic cellular functions, such as transcription, DNA replication and repair of DNA damage. Accordingly, a range of proteins modify and/or read chromatin states to regulate access to chromosomal DNA. Yeast Dot1 and the mammalian homologue DOT1L are methyltransferases that can add up to three methyl groups to histone H3 lysine 79 (H3K79). H3K79 methylation is implicated in several processes, including transcription elongation by RNA polymerase II, the DNA damage response and cell cycle checkpoint activation. DOT1L is also an important drug target for treatment of mixed lineage leukemia (MLL)-rearranged leukemia where aberrant transcriptional activation is promoted by DOT1L mislocalisation. This review summarizes what is currently known about the role of Dot1/DOT1L and H3K79 methylation in transcription and genomic stability.
DOT1L and H3K79 Methylation in Transcription and Genomic Stability

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Katherine Wood

2018-02-01

Full Text Available The organization of eukaryotic genomes into chromatin provides challenges for the cell to accomplish basic cellular functions, such as transcription, DNA replication and repair of DNA damage. Accordingly, a range of proteins modify and/or read chromatin states to regulate access to chromosomal DNA. Yeast Dot1 and the mammalian homologue DOT1L are methyltransferases that can add up to three methyl groups to histone H3 lysine 79 (H3K79. H3K79 methylation is implicated in several processes, including transcription elongation by RNA polymerase II, the DNA damage response and cell cycle checkpoint activation. DOT1L is also an important drug target for treatment of mixed lineage leukemia (MLL-rearranged leukemia where aberrant transcriptional activation is promoted by DOT1L mislocalisation. This review summarizes what is currently known about the role of Dot1/DOT1L and H3K79 methylation in transcription and genomic stability.
YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

International Nuclear Information System (INIS)

Lin, Yi-Ting; Ding, Jing-Ya; Li, Ming-Yang; Yeh, Tien-Shun; Wang, Tsu-Wei; Yu, Jenn-Yah

2012-01-01

Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: ► YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. ► YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. ► Knockdown of Gli2 rescues the Yap-overexpression phenotype in P19 cells. ► Knockdown of Gli2 rescues the Yap
YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

Energy Technology Data Exchange (ETDEWEB)

Lin, Yi-Ting; Ding, Jing-Ya [Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan (China); Li, Ming-Yang [Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan (China); Yeh, Tien-Shun [Department of Anatomy and Cell Biology, National Yang-Ming University, Taipei 112, Taiwan (China); Wang, Tsu-Wei [Department of Life Science, National Taiwan Normal University, Taipei 116, Taiwan (China); Yu, Jenn-Yah [Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei 112, Taiwan (China); Brain Research Center, National Yang-Ming University, Taipei 112, Taiwan (China)

2012-09-10

Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: Black-Right-Pointing-Pointer YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. Black-Right-Pointing-Pointer YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. Black-Right-Pointing-Pointer Knockdown of Gli2 rescues the Yap
Lithium inhibits tumorigenic potential of PDA cells through targeting hedgehog-GLI signaling pathway.

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Zhonglu Peng

Full Text Available Hedgehog signaling pathway plays a critical role in the initiation and development of pancreatic ductal adenocarcinoma (PDA and represents an attractive target for PDA treatment. Lithium, a clinical mood stabilizer for mental disorders, potently inhibits the activity of glycogen synthase kinase 3β (GSK3β that promotes the ubiquitin-dependent proteasome degradation of GLI1, an important downstream component of hedgehog signaling. Herein, we report that lithium inhibits cell proliferation, blocks G1/S cell-cycle progression, induces cell apoptosis and suppresses tumorigenic potential of PDA cells through down-regulation of the expression and activity of GLI1. Moreover, lithium synergistically enhances the anti-cancer effect of gemcitabine. These findings further our knowledge of mechanisms of action for lithium and provide a potentially new therapeutic strategy for PDA through targeting GLI1.
Identification and Validation of Novel Hedgehog-Responsive Enhancers Predicted by Computational Analysis of Ci/Gli Binding Site Density

Science.gov (United States)

Richards, Neil; Parker, David S.; Johnson, Lisa A.; Allen, Benjamin L.; Barolo, Scott; Gumucio, Deborah L.

2015-01-01

The Hedgehog (Hh) signaling pathway directs a multitude of cellular responses during embryogenesis and adult tissue homeostasis. Stimulation of the pathway results in activation of Hh target genes by the transcription factor Ci/Gli, which binds to specific motifs in genomic enhancers. In Drosophila, only a few enhancers (patched, decapentaplegic, wingless, stripe, knot, hairy, orthodenticle) have been shown by in vivo functional assays to depend on direct Ci/Gli regulation. All but one (orthodenticle) contain more than one Ci/Gli site, prompting us to directly test whether homotypic clustering of Ci/Gli binding sites is sufficient to define a Hh-regulated enhancer. We therefore developed a computational algorithm to identify Ci/Gli clusters that are enriched over random expectation, within a given region of the genome. Candidate genomic regions containing Ci/Gli clusters were functionally tested in chicken neural tube electroporation assays and in transgenic flies. Of the 22 Ci/Gli clusters tested, seven novel enhancers (and the previously known patched enhancer) were identified as Hh-responsive and Ci/Gli-dependent in one or both of these assays, including: Cuticular protein 100A (Cpr100A); invected (inv), which encodes an engrailed-related transcription factor expressed at the anterior/posterior wing disc boundary; roadkill (rdx), the fly homolog of vertebrate Spop; the segment polarity gene gooseberry (gsb); and two previously untested regions of the Hh receptor-encoding patched (ptc) gene. We conclude that homotypic Ci/Gli clustering is not sufficient information to ensure Hh-responsiveness; however, it can provide a clue for enhancer recognition within putative Hedgehog target gene loci. PMID:26710299
Nfatc1 Is a Functional Transcriptional Factor Mediating Nell-1-Induced Runx3 Upregulation in Chondrocytes

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Chenshuang Li

2018-01-01

Full Text Available Neural EGFL like 1 (Nell-1 is essential for chondrogenic differentiation, maturation, and regeneration. Our previous studies have demonstrated that Nell-1’s pro-chondrogenic activities are predominantly reliant upon runt-related transcription factor 3 (Runx3-mediated Indian hedgehog (Ihh signaling. Here, we identify the nuclear factor of activated T-cells 1 (Nfatc1 as the key transcriptional factor mediating the Nell-1 → Runx3 signal transduction in chondrocytes. Using chromatin immunoprecipitation assay, we were able to determine that Nfatc1 binds to the −833–−810 region of the Runx3-promoter in response to Nell-1 treatment. By revealing the Nell-1 → Nfatc1 → Runx3 → Ihh cascade, we demonstrate the involvement of Nfatc1, a nuclear factor of activated T-cells, in chondrogenesis, while providing innovative insights into developing a novel therapeutic strategy for cartilage regeneration and other chondrogenesis-related conditions.
Modulation of mitochondrial activity in HaCaT keratinocytes by the cell penetrating peptide Z-Gly-RGD(DPhe)-mitoparan.

Science.gov (United States)

Richardson, Adam; Muir, Lewis; Mousdell, Sasha; Sexton, Darren; Jones, Sarah; Howl, John; Ross, Kehinde

2018-01-30

Biologically active cell penetrating peptides (CPPs) are an emerging class of therapeutic agent. The wasp venom peptide mastoparan is an established CPP that modulates mitochondrial activity and triggers caspase-dependent apoptosis in cancer cells, as does the mastoparan analogue mitoparan (mitP). Mitochondrial depolarisation and activation of the caspase cascade also underpins the action of dithranol, a topical agent for treatment of psoriasis. The effects of a potent mitP analogue on mitochondrial activity were therefore examined to assess its potential as a novel approach for targeting mitochondria for the treatment of psoriasis. In HaCaT keratinocytes treated with the mitP analogue Z-Gly-RGD(DPhe)-mitP for 24 h, a dose-dependent loss of mitochondrial activity was observed using the methyl-thiazolyl-tetrazolium (MTT) assay. At 10 μmol L -1 , MTT activity was less than 30% that observed in untreated cells. Staining with the cationic dye JC-1 suggested that Z-Gly-RGD(DPhe)-mitP also dissipated the mitochondrial membrane potential, with a threefold increase in mitochondrial depolarisation levels. However, caspase activity appeared to be reduced by 24 h exposure to Z-Gly-RGD(DPhe)-mitP treatment. Furthermore, Z-Gly-RGD(DPhe)-mitP treatment had little effect on overall cell viability. Our findings suggest Z-Gly-RGD(DPhe)-mitP promotes the loss of mitochondrial activity but does not appear to evoke apoptosis in HaCaT keratinocytes.
COBRA1 inhibits AP-1 transcriptional activity in transfected cells

International Nuclear Information System (INIS)

Zhong Hongjun; Zhu Jianhua; Zhang Hao; Ding Lihua; Sun Yan; Huang Cuifen; Ye Qinong

2004-01-01

Mutations in the breast cancer susceptibility gene (BRCA1) account for a significant proportion of hereditary breast and ovarian cancers. Cofactor of BRCA1 (COBRA1) was isolated as a BRCA1-interacting protein and exhibited a similar chromatin reorganizing activity to that of BRCA1. However, the biological role of COBRA1 remains largely unexplored. Here, we report that ectopic expression of COBRA1 inhibited activator protein 1 (AP-1) transcriptional activity in transfected cells in a dose-dependent manner, whereas reduction of endogenous COBRA1 with a small interfering RNA significantly enhanced AP-1-mediated transcriptional activation. COBRA1 physically interacted with the AP-1 family members, c-Jun and c-Fos, and the middle region of COBRA1 bound to c-Fos. Lack of c-Fos binding site in the COBRA1 completely abolished the COBRA1 inhibition of AP-1 trans-activation. These findings suggest that COBRA1 may directly modulate AP-1 pathway and, therefore, may play important roles in cell proliferation, differentiation, apoptosis, and oncogenesis
A transcriptional coregulator, SPIN·DOC, attenuates the coactivator activity of Spindlin1.

Science.gov (United States)

Bae, Narkhyun; Gao, Min; Li, Xu; Premkumar, Tolkappiyan; Sbardella, Gianluca; Chen, Junjie; Bedford, Mark T

2017-12-22

Spindlin1 (SPIN1) is a transcriptional coactivator with critical functions in embryonic development and emerging roles in cancer. SPIN1 harbors three Tudor domains, two of which engage the tail of histone H3 by reading the H3-Lys-4 trimethylation and H3-Arg-8 asymmetric dimethylation marks. To gain mechanistic insight into how SPIN1 functions as a transcriptional coactivator, here we purified its interacting proteins. We identified an uncharacterized protein (C11orf84), which we renamed SPIN1 docking protein (SPIN·DOC), that directly binds SPIN1 and strongly disrupts its histone methylation reading ability, causing it to disassociate from chromatin. The Spindlin family of coactivators has five related members (SPIN1, 2A, 2B, 3, and 4), and we found that all of them bind SPIN·DOC. It has been reported previously that SPIN1 regulates gene expression in the Wnt signaling pathway by directly interacting with transcription factor 4 (TCF4). We observed here that SPIN·DOC associates with TCF4 in a SPIN1-dependent manner and dampens SPIN1 coactivator activity in TOPflash reporter assays. Furthermore, knockdown and overexpression experiments indicated that SPIN·DOC represses the expression of a number of SPIN1-regulated genes, including those encoding ribosomal RNA and the cytokine IL1B. In conclusion, we have identified SPIN·DOC as a transcriptional repressor that binds SPIN1 and masks its ability to engage the H3-Lys-4 trimethylation activation mark. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Gly184 of the Escherichia coli cAMP receptor protein provides optimal context for both DNA binding and RNA polymerase interaction.

Science.gov (United States)

Hicks, Matt N; Gunasekara, Sanjiva; Serate, Jose; Park, Jin; Mosharaf, Pegah; Zhou, Yue; Lee, Jin-Won; Youn, Hwan

2017-10-01

The Escherichia coli cAMP receptor protein (CRP) utilizes the helix-turn-helix motif for DNA binding. The CRP's recognition helix, termed F-helix, includes a stretch of six amino acids (Arg180, Glu181, Thr182, Val183, Gly184, and Arg185) for direct DNA contacts. Arg180, Glu181 and Arg185 are known as important residues for DNA binding and specificity, but little has been studied for the other residues. Here we show that Gly184 is another F-helix residue critical for the transcriptional activation function of CRP. First, glycine was repeatedly selected at CRP position 184 for its unique ability to provide wild type-level transcriptional activation activity. To dissect the glycine requirement, wild type CRP and mutants G184A, G184F, G184S, and G184Y were purified and their in vitro DNA-binding activity was measured. G184A and G184F displayed reduced DNA binding, which may explain their low transcriptional activation activity. However, G184S and G184Y displayed apparently normal DNA affinity. Therefore, an additional factor is needed to account for the diminished transcriptional activation function in G184S and G184Y, and the best explanation is perturbations in their interaction with RNA polymerase. The fact that glycine is the smallest amino acid could not fully warrant its suitability, as shown in this study. We hypothesize that Gly184 fulfills the dual functions of DNA binding and RNA polymerase interaction by conferring conformational flexibility to the F-helix.

The metabolic activator FOXO1 binds hepatitis B virus DNA and activates its transcription

International Nuclear Information System (INIS)

Shlomai, Amir; Shaul, Yosef

2009-01-01

Hepatitis B virus (HBV) is a small DNA virus that targets the liver and infects humans worldwide. Recently we have shown that the metabolic regulator PGC-1α coactivates HBV transcription thereby rendering the virus susceptible to fluctuations in the nutritional status of the liver. PGC-1α coactivation of HBV is mediated through the liver-enriched nuclear receptor HNF4α and through another yet unknown transcription factor(s). Here we show that the forkhead transcription factor FOXO1, a known target for PGC-1α coactivation and a central mediator of glucose metabolism in the liver, binds HBV core promoter and activates its transcription. This activation is further enhanced in the presence of PGC-1α, implying that FOXO1 is a target for PGC-1α coactivation of HBV transcription. Thus, our results identify another key metabolic regulator as an activator of HBV transcription, thereby supporting the principle that HBV gene expression is regulated in a similar way to key hepatic metabolic genes.
Adult Gli2+/-;Gli3Δ699/+ Male and Female Mice Display a Spectrum of Genital Malformation.

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Fei He

Full Text Available Disorders of sexual development (DSD encompass a broad spectrum of urogenital malformations and are amongst the most common congenital birth defects. Although key genetic factors such as the hedgehog (Hh family have been identified, a unifying postnatally viable model displaying the spectrum of male and female urogenital malformations has not yet been reported. Since human cases are diagnosed and treated at various stages postnatally, equivalent mouse models enabling analysis at similar stages are of significant interest. Additionally, all non-Hh based genetic models investigating DSD display normal females, leaving female urogenital development largely unknown. Here, we generated compound mutant mice, Gli2+/-;Gli3Δ699/+, which exhibit a spectrum of urogenital malformations in both males and females upon birth, and also carried them well into adulthood. Analysis of embryonic day (E18.5 and adult mice revealed shortened anogenital distance (AGD, open ventral urethral groove, incomplete fusion of scrotal sac, abnormal penile size and structure, and incomplete testicular descent with hypoplasia in male mice, whereas female mutant mice displayed reduced AGD, urinary incontinence, and a number of uterine anomalies such as vaginal duplication. Male and female fertility was also investigated via breeding cages, and it was identified that male mice were infertile while females were unable to deliver despite becoming impregnated. We propose that Gli2+/-;Gli3Δ699/+ mice can serve as a genetic mouse model for common DSD such as cryptorchidism, hypospadias, and incomplete fusion of the scrotal sac in males, and a spectrum of uterine and vaginal abnormalities along with urinary incontinence in females, which could prove essential in revealing new insights into their equivalent diseases in humans.
Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling.

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Alexandre N Ermilov

2016-11-01

Full Text Available For homeostasis, lingual taste papilla organs require regulation of epithelial cell survival and renewal, with sustained innervation and stromal interactions. To investigate a role for Hedgehog/GLI signaling in adult taste organs we used a panel of conditional mouse models to manipulate GLI activity within epithelial cells of the fungiform and circumvallate papillae. Hedgehog signaling suppression rapidly led to taste bud loss, papilla disruption, and decreased proliferation in domains of papilla epithelium that contribute to taste cells. Hedgehog responding cells were eliminated from the epithelium but retained in the papilla stromal core. Despite papilla disruption and loss of taste buds that are a major source of Hedgehog ligand, innervation to taste papillae was maintained, and not misdirected, even after prolonged GLI blockade. Further, vimentin-positive fibroblasts remained in the papilla core. However, retained innervation and stromal cells were not sufficient to maintain taste bud cells in the context of compromised epithelial Hedgehog signaling. Importantly taste organ disruption after GLI blockade was reversible in papillae that retained some taste bud cell remnants where reactivation of Hedgehog signaling led to regeneration of papilla epithelium and taste buds. Therefore, taste bud progenitors were either retained during epithelial GLI blockade or readily repopulated during recovery, and were poised to regenerate taste buds once Hedgehog signaling was restored, with innervation and papilla connective tissue elements in place. Our data argue that Hedgehog signaling is essential for adult tongue tissue maintenance and that taste papilla epithelial cells represent the key targets for physiologic Hedgehog-dependent regulation of taste organ homeostasis. Because disruption of GLI transcriptional activity in taste papilla epithelium is sufficient to drive taste organ loss, similar to pharmacologic Hedgehog pathway inhibition, the findings
Maintenance of Taste Organs Is Strictly Dependent on Epithelial Hedgehog/GLI Signaling.

Science.gov (United States)

Ermilov, Alexandre N; Kumari, Archana; Li, Libo; Joiner, Ariell M; Grachtchouk, Marina A; Allen, Benjamin L; Dlugosz, Andrzej A; Mistretta, Charlotte M

2016-11-01

For homeostasis, lingual taste papilla organs require regulation of epithelial cell survival and renewal, with sustained innervation and stromal interactions. To investigate a role for Hedgehog/GLI signaling in adult taste organs we used a panel of conditional mouse models to manipulate GLI activity within epithelial cells of the fungiform and circumvallate papillae. Hedgehog signaling suppression rapidly led to taste bud loss, papilla disruption, and decreased proliferation in domains of papilla epithelium that contribute to taste cells. Hedgehog responding cells were eliminated from the epithelium but retained in the papilla stromal core. Despite papilla disruption and loss of taste buds that are a major source of Hedgehog ligand, innervation to taste papillae was maintained, and not misdirected, even after prolonged GLI blockade. Further, vimentin-positive fibroblasts remained in the papilla core. However, retained innervation and stromal cells were not sufficient to maintain taste bud cells in the context of compromised epithelial Hedgehog signaling. Importantly taste organ disruption after GLI blockade was reversible in papillae that retained some taste bud cell remnants where reactivation of Hedgehog signaling led to regeneration of papilla epithelium and taste buds. Therefore, taste bud progenitors were either retained during epithelial GLI blockade or readily repopulated during recovery, and were poised to regenerate taste buds once Hedgehog signaling was restored, with innervation and papilla connective tissue elements in place. Our data argue that Hedgehog signaling is essential for adult tongue tissue maintenance and that taste papilla epithelial cells represent the key targets for physiologic Hedgehog-dependent regulation of taste organ homeostasis. Because disruption of GLI transcriptional activity in taste papilla epithelium is sufficient to drive taste organ loss, similar to pharmacologic Hedgehog pathway inhibition, the findings suggest that taste
Stimulation of p38 (HOG1) kinase pathway by ionizing radiation results in downstream modulation of ATF/CREB transcription factor activity in NIH-3T3 cells

International Nuclear Information System (INIS)

Stevenson, Mary Ann; Yao Jin

1997-01-01

Purpose/Objective:p38 kinase, a member of the MAP kinase family, is activated in response to stresses such as high osmolarity and UV irradiation as well exposure to cytokines such as IL1β and TNFα. The kinase is part of a signal transduction pathway that leads from receptor activation through a three kinase cascade resulting in the activation of p38. p38 activation then leads to the phosphorylation of target proteins that include transcription factors such as nuclear factor of interleukin 6 and members of the activating transcription factor (ATF) family, and in addition, the stress protein, HSP27, via activation of MAPKAP2 kinase. In the present report, we have investigated the potential role of p38 in the response of NIH-3T3 cells to ionizing radiation. Materials and Methods:NIH-3T3 cells were grown to confluence in DMEM+10%CS and then serum deprived for 24 hours in DMEM+0.1%CS. Radiation exposures were delivered using a Philips RT250 (250Kvp X-ray tube). Activated forms of p38 kinase and ATF/CREB transcription factors were identified using immunoblotting techniques employing activation specific antibodies raised against the phosphorylated forms of the kinases/transcription factors. Kinase activity was directly measured using immunokinase assays. DNA binding of transcription factors to their respective consensus sequences was assayed by EMSA. Results:We found that p38 becomes rapidly phosphorylated and activated by exposure to ionizing radiation. Significantly, p38 is activated to a similar degree and with a similar time course by serum derpviation and entry of cells into a non-proliferating G 0 state, suggesting a causal role for p38 in quiescence. Phosphorylation of p38 directly correlated with phosphorylation and activation of ATF/CREB family members as well as DNA binding by these activated factors. Conclusion:Activation of p38 kinase and downstream transcription factors may play an important role in the response of cells to ionizing radiation. We are
Indian Hedgehog Signaling Regulates Transcription and Expression of Collagen Type X via Runx2/Smads Interactions*

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Amano, Katsuhiko; Densmore, Michael; Nishimura, Riko; Lanske, Beate

2014-01-01

Indian hedgehog (Ihh) is essential for chondrocyte differentiation and endochondral ossification and acts with parathyroid hormone-related peptide in a negative feedback loop to regulate early chondrocyte differentiation and entry to hypertrophic differentiation. Independent of this function, we and others recently reported independent Ihh functions to promote chondrocyte hypertrophy and matrix mineralization in vivo and in vitro. However, the molecular mechanisms for these actions and their functional significance are still unknown. We recently discovered that Ihh overexpression in chondrocytes stimulated the expression of late chondrocyte differentiation markers and induced matrix mineralization. Focusing on collagen type X (Col10α1) expression and transcription, we observed that hedgehog downstream transcription factors GLI-Krüppel family members (Gli) 1/2 increased COL10A1 promoter activity and identified a novel Gli1/2 response element in the 250-bp basic promoter. In addition, we found that Ihh induced Runx2 expression in chondrocytes without up-regulating other modulators of chondrocyte maturation such as Mef2c, Foxa2, and Foxa3. Runx2 promoted Col10α1 expression in cooperation with Ihh. Further analyses using promoter assays, immunofluorescence, and binding assays showed the interaction of Gli1/2 in a complex with Runx2/Smads induces chondrocyte differentiation. Finally, we could demonstrate that Ihh promotes in vitro matrix mineralization using similar molecular mechanisms. Our data provide an in vitro mechanism for Ihh signaling to positively regulate Col10α1 transcription. Thus, Ihh signaling could be an important player for not only early chondrocyte differentiation but maturation and calcification of chondrocytes. PMID:25028519
Role of GLI2 in hypopituitarism phenotype.

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Arnhold, Ivo J P; França, Marcela M; Carvalho, Luciani R; Mendonca, Berenice B; Jorge, Alexander A L

2015-06-01

GLI2 is a zinc-finger transcription factor involved in the Sonic Hedgehog pathway. Gli2 mutant mice have hypoplastic anterior and absent posterior pituitary glands. We reviewed the literature for patients with hypopituitarism and alterations in GLI2. Twenty-five patients (16 families) had heterozygous truncating mutations, and the phenotype frequently included GH deficiency, a small anterior pituitary lobe and an ectopic/undescended posterior pituitary lobe on magnetic resonance imaging and postaxial polydactyly. The inheritance pattern was autosomal dominant with incomplete penetrance and variable expressivity. The mutation was frequently inherited from an asymptomatic parent. Eleven patients had heterozygous non-synonymous GLI2 variants that were classified as variants of unknown significance, because they were either absent from or had a frequency lower than 0.001 in the databases. In these patients, the posterior pituitary was also ectopic, but none had polydactyly. A third group of variants found in patients with hypopituitarism were considered benign because their frequency was ≥ 0.001 in the databases. GLI2 is a large and polymorphic gene, and sequencing may identify variants whose interpretation may be difficult. Incomplete penetrance implies in the participation of other genetic and/or environmental factors. An interaction between Gli2 mutations and prenatal ethanol exposure has been demonstrated in mice dysmorphology. In conclusion, a relatively high frequency of GLI2 mutations and variants were identified in patients with congenital GH deficiency without other brain defects, and most of these patients presented with combined pituitary hormone deficiency and an ectopic posterior pituitary lobe. Future studies may clarify the relative role and frequency of GLI2 alterations in the aetiology of hypopituitarism. © 2015 Society for Endocrinology.
Zinc-fingers and homeoboxes 1 (ZHX1) binds DNA methyltransferase (DNMT) 3B to enhance DNMT3B-mediated transcriptional repression

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Kim, Sung-Hak; Park, Jinah; Choi, Moon-Chang; Kim, Hwang-Phill; Park, Jung-Hyun; Jung, Yeonjoo; Lee, Ju-Hee; Oh, Do-Youn; Im, Seock-Ah; Bang, Yung-Jue; Kim, Tae-You

2007-01-01

DNA methyltransferases (DNMT) 3B is a de novo DNMT that represses transcription independent of DNMT activity. In order to gain a better insight into DNMT3B-mediated transcriptional repression, we performed a yeast two-hybrid analysis using DNMT3B as a bait. Of the various binding candidates, ZHX1, a member of zinc-finger and homeobox protein, was found to interact with DNMT3B in vivo and in vitro. N-terminal PWWP domain of DNMT3B was required for its interaction with homeobox motifs of ZHX1. ZHX1 contains nuclear localization signal at C-terminal homeobox motif, and both ZHX1 and DNMT3B were co-localized in nucleus. Furthermore, we found that ZHX1 enhanced the transcriptional repression mediated by DNMT3B when DNMT3B is directly targeted to DNA. These results showed for First the direct linkage between DNMT and zinc-fingers homeoboxes protein, leading to enhanced gene silencing by DNMT3B
PEA3activates CXCL12transcription in MCF-7breast cancer cells%PEA3 activates CXCL12 transcription in MCF-7 breast cancer cells

Institute of Scientific and Technical Information of China (English)

CHEN Li; CHEN Bo-bin; LI Jun-jie; JIN Wei; SHAO Zhi-min

2011-01-01

Objective To explore the activity of PEA3 ( polyomavirus enhancer activator 3 ) on CXCL12 (Chemokine CXC motif ligand 12) transcription and to reveal the role of PEA3 involved in CXCL12-mediated metastasis and angiogenesis in breast cancer. Methods Methods such as cell transfection, ChIP assay (chromatin immunoprecipitation ), and siRNA (small interfering RNA) were applied to demonstrate and confirm the interaction between PEA3 and CXCL12. Results Over-expression of PEA3 could increase the CXCL12 mRNA level and the CXCL12 promoter activity in human MCF-7 breast cancer cells. ChIP assay demonstrated that PEA3 could bind to the CXCL12 promoter in the cells transfected with PEA3 expression vector. PEA3 siRNA decreased CXCL12 promoter activity and the binding of PEA3 to the CXCL12 promoter in MCF-7 cells. Conclusions PEA3 could activate CXCL12 promoter transcription. It may be a potential mechanism of tumor angiogenesis and metastasis regarding of PEA3 and CXCL12.
Transcriptional repressor role of PocR on the 1,3-propanediol biosynthetic pathway by Lactobacillus panis PM1.

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Kang, Tae Sun; Korber, Darren R; Tanaka, Takuji

2014-06-01

The regulatory role of a transcriptional regulator (PocR) in the 1,3-propanediol biosynthetic pathway of Lactobacillus panis PM1 contributes to the optimization of 1,3-propanediol production by this strain, which potentially will lead to 1,3-propanediol manufacturing efficiencies. Lactobacillus panis PM1 can utilize a 1,3-propanediol (1,3-PDO) biosynthetic pathway, consisting of diol dehydratase (PduCDE) and 1,3-PDO dehydrogenase, as a NADH recycling system, to survive under various environmental conditions. In this study, we identified a key transcriptional repressor (PocR) which was annotated as a transcriptional factor of AraC family as part of the 1,3-PDO biosynthetic pathway of L. panis PM1. The over-expression of the PocR gene resulted in the significant repression (81 %) of pduC (PduCDE large subunit) transcription, and subsequently, the decreased activity of PduCDE by 22 %. As a result of the regulation of PduCDE, production of both 3-hydroxypropionaldehyde and 1,3-PDO in the PocR over-expressing strain were significantly decreased by 40 % relative to the control strain. These results clearly demonstrate the transcriptional repressor role of PocR in the 1,3-PDO biosynthetic pathway.
In vivo evidence suggesting reciprocal renal hypoxia-inducible factor-1 upregulation and signal transducer and activator of transcription 3 activation in response to hypoxic and non-hypoxic stimuli.

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Nechemia-Arbely, Yael; Khamaisi, Mogher; Rosenberger, Christian; Koesters, Robert; Shina, Ahuva; Geva, Carmit; Shriki, Anat; Klaus, Stephen; Rosen, Seymour; Rose-John, Stefan; Galun, Eithan; Axelrod, Jonathan H; Heyman, Samuel N

2013-04-01

In vitro studies suggest that combined activation of hypoxia-inducible factor (HIF) and signal transducer and activator of transcription 3 (STAT3) promotes the hypoxia response. However, their interrelationship in vivo remains poorly defined. The present study investigated the possible relationship between HIF-1 upregulation and STAT3 activation in the rodent kidney in vivo. Activation of HIF-1 and STAT3 was analysed by immunohistochemical staining and western blot analysis in: (i) models of hypoxia-associated kidney injury induced by radiocontrast media or rhabdomyolysis; (ii) following activation of STAT3 by the interleukin (IL)-6-soluble IL-6 receptor complex; or (iii) following HIF-1α stabilization using hypoxic and non-hypoxic stimuli (mimosine, FG-4497, CO, CoCl(2)) and in targeted von Hippel-Lindau-knockout mice. Western blot analysis and immunostaining revealed marked induction of both transcription factors under all conditions tested, suggesting that in vivo STAT3 can trigger HIF and vice versa. Colocalization of HIF-1α and phosphorylated STAT3 was detected in some, but not all, renal cell types, suggesting that in some cells a paracrine mechanism may be responsible for the reciprocal activation of the two transcription factors. Nevertheless, in several cell types spatial concordance was observed under the majority of conditions tested, suggesting that HIF-1 and STAT3 may act as cotranscription factors. These in vivo studies suggest that, in response to renal hypoxic-stress, upregulation of HIF-1 and activation of STAT3 may be both reciprocal and cell type dependent. © 2013 The Authors Clinical and Experimental Pharmacology and Physiology © 2013 Wiley Publishing Asia Pty Ltd.
Cyclin D3 interacts with vitamin D receptor and regulates its transcription activity

International Nuclear Information System (INIS)

Jian Yongzhi; Yan Jun; Wang Hanzhou; Chen Chen; Sun Maoyun; Jiang Jianhai; Lu Jieqiong; Yang Yanzhong; Gu Jianxin

2005-01-01

D-type cyclins are essential for the progression through the G1 phase of the cell cycle. Besides serving as cell cycle regulators, D-type cyclins were recently reported to have transcription regulation functions. Here, we report that cyclin D3 is a new interacting partner of vitamin D receptor (VDR), a member of the superfamily of nuclear receptors for steroid hormones, thyroid hormone, and the fat-soluble vitamins A and D. The interaction was confirmed with methods of yeast two-hybrid system, in vitro binding analysis and in vivo co-immunoprecipitation. Cyclin D3 interacted with VDR in a ligand-independent manner, but treatment of the ligand, 1,25-dihydroxyvitamin D3, strengthened the interaction. Confocal microscopy analysis showed that ligand-activated VDR led to an accumulation of cyclin D3 in the nuclear region. Cyclin D3 up-regulated transcriptional activity of VDR and this effect was counteracted by overexpression of CDK4 and CDK6. These findings provide us a new clue to understand the transcription regulation functions of D-type cyclins
Elk3 from hamster-a ternary complex factor with strong transcriptional repressor activity

DEFF Research Database (Denmark)

Hjortoe, G.M.; Weilguny, D.; Willumsen, Berthe Marie

2005-01-01

the transcription of genes that are activated during entry into G1. We have isolated the Cricetulus griseus Elk3 gene from the Chinese hamster ovary (CHO) cell line and investigated the transcriptional potential of this factor. Transient transfections revealed that, in addition to its regulation of the c......-fos promoter, Elk3 from CHO cells seems to inhibit other promoters controlling expression of proteins involved in G1/S phase progression; Cyclin D1 and DHFR. As has been described for the Elk3 homologs Net (Mouse) and Sap-2 (Human), the results of the present study further indicate that hamster Elk3...
Targeted deficiency of the transcriptional activator Hnf1alpha alters subnuclear positioning of its genomic targets.

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Reini F Luco

2008-05-01

Full Text Available DNA binding transcriptional activators play a central role in gene-selective regulation. In part, this is mediated by targeting local covalent modifications of histone tails. Transcriptional regulation has also been associated with the positioning of genes within the nucleus. We have now examined the role of a transcriptional activator in regulating the positioning of target genes. This was carried out with primary beta-cells and hepatocytes freshly isolated from mice lacking Hnf1alpha, an activator encoded by the most frequently mutated gene in human monogenic diabetes (MODY3. We show that in Hnf1a-/- cells inactive endogenous Hnf1alpha-target genes exhibit increased trimethylated histone H3-Lys27 and reduced methylated H3-Lys4. Inactive Hnf1alpha-targets in Hnf1a-/- cells are also preferentially located in peripheral subnuclear domains enriched in trimethylated H3-Lys27, whereas active targets in wild-type cells are positioned in more central domains enriched in methylated H3-Lys4 and RNA polymerase II. We demonstrate that this differential positioning involves the decondensation of target chromatin, and show that it is spatially restricted rather than a reflection of non-specific changes in the nuclear organization of Hnf1a-deficient cells. This study, therefore, provides genetic evidence that a single transcriptional activator can influence the subnuclear location of its endogenous genomic targets in primary cells, and links activator-dependent changes in local chromatin structure to the spatial organization of the genome. We have also revealed a defect in subnuclear gene positioning in a model of a human transcription factor disease.
FTH1P3, a Novel H-Ferritin Pseudogene Transcriptionally Active, Is Ubiquitously Expressed and Regulated during Cell Differentiation.

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Maddalena Di Sanzo

Full Text Available Ferritin, the major iron storage protein, performs its essential functions in the cytoplasm, nucleus and mitochondria. The variable assembly of 24 subunits of the Heavy (H and Light (L type composes the cytoplasmic molecule. In humans, two distinct genes code these subunits, both belonging to complex multigene families. Until now, one H gene has been identified with the coding sequence interrupted by three introns and more than 20 intronless copies widely dispersed on different chromosomes. Two of the intronless genes are actively transcribed in a tissue-specific manner. Herein, we report that FTH1P3, another intronless pseudogene, is transcribed. FTH1P3 transcript was detected in several cell lines and tissues, suggesting that its transcription is ubiquitary, as it happens for the parental ferritin H gene. Moreover, FTH1P3 expression is positively regulated during the cell differentiation process.
GliZ, a transcriptional regulator of gliotoxin in Aspergillus fumigatus

DEFF Research Database (Denmark)

Bok, J.W.; Chung, D.W.; Balajee, A.

2006-01-01

Gliotoxin is a nonribosomal peptide produced by Aspergillus fumigatus. This compound has been proposed as an A. fumigatus virulence factor due to its cytotoxic, genotoxic, and apoptotic properties. Recent identification of the gliotoxin gene cluster identified several genes (gli genes) likely inv...
Histone deacetylase 3 represses p15INK4b and p21WAF1/cip1 transcription by interacting with Sp1

International Nuclear Information System (INIS)

Huang Weifeng; Tan Dapeng; Wang Xiuli; Han Songyan; Tan Jiang; Zhao Yanmei; Lu Jun; Huang Baiqu

2006-01-01

Histone deacetylase 3 (HDAC3) has been implicated to play roles in governing cell proliferation. Here we demonstrated that the overexpression of HDAC3 repressed transcription of p15 INK4b and p21 WAF1/cip1 genes in 293T cells, and that the recruitment of HDAC3 to the promoter regions of these genes was critical to this repression. We also showed that HDAC3 repressed GAL4-Sp1 transcriptional activity, and that Sp1 was co-immunoprecipitated with FLAG-tagged HDAC3. We conclude that HDAC3 can repress p15 INK4b and p21 WAF1/cip1 transcription by interacting with Sp1. Furthermore, knockdown of HDAC3 by RNAi up-regulated the transcriptional expression of p15 INK4b , but not that of p21 WAF1/cip1 , implicating the different roles of HDAC3 in repression of p15 INK4b and p21 WAF1/cip1 transcription. Data from this study indicate that the inhibition of p15 INK4b and p21 WAF1/cip1 may be one of the mechanisms by which HDAC3 participates in cell cycle regulation and oncogenesis
The roles of the catalytic and noncatalytic activities of Rpd3L and Rpd3S in the regulation of gene transcription in yeast.

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Daniella Yeheskely-Hayon

Full Text Available In budding yeasts, the histone deacetylase Rpd3 resides in two different complexes called Rpd3L (large and Rpd3S (small that exert opposing effects on the transcription of meiosis-specific genes. By introducing mutations that disrupt the integrity and function of either Rpd3L or Rpd3S, we show here that Rpd3 function is determined by its association with either of these complexes. Specifically, the catalytic activity of Rpd3S activates the transcription of the two major positive regulators of meiosis, IME1 and IME2, under all growth conditions and activates the transcription of NDT80 only during vegetative growth. In contrast, the effects of Rpd3L depends on nutrients; it represses or activates transcription in the presence or absence of a nitrogen source, respectively. Further, we show that transcriptional activation does not correlate with histone H4 deacetylation, suggesting an effect on a nonhistone protein. Comparison of rpd3-null and catalytic-site point mutants revealed an inhibitory activity that is independent of either the catalytic activity of Rpd3 or the integrity of Rpd3L and Rpd3S.
The Roles of the Catalytic and Noncatalytic Activities of Rpd3L and Rpd3S in the Regulation of Gene Transcription in Yeast

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Yeheskely-Hayon, Daniella; Kotler, Anat; Stark, Michal; Hashimshony, Tamar; Sagee, Shira; Kassir, Yona

2013-01-01

In budding yeasts, the histone deacetylase Rpd3 resides in two different complexes called Rpd3L (large) and Rpd3S (small) that exert opposing effects on the transcription of meiosis-specific genes. By introducing mutations that disrupt the integrity and function of either Rpd3L or Rpd3S, we show here that Rpd3 function is determined by its association with either of these complexes. Specifically, the catalytic activity of Rpd3S activates the transcription of the two major positive regulators of meiosis, IME1 and IME2, under all growth conditions and activates the transcription of NDT80 only during vegetative growth. In contrast, the effects of Rpd3L depends on nutrients; it represses or activates transcription in the presence or absence of a nitrogen source, respectively. Further, we show that transcriptional activation does not correlate with histone H4 deacetylation, suggesting an effect on a nonhistone protein. Comparison of rpd3-null and catalytic-site point mutants revealed an inhibitory activity that is independent of either the catalytic activity of Rpd3 or the integrity of Rpd3L and Rpd3S. PMID:24358376
Indian Hedgehog signaling pathway members are associated with magnetic resonance imaging manifestations and pathological scores in lumbar facet joint osteoarthritis

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Shuang, Feng; Zhou, Ying; Hou, Shu-Xun; Zhu, Jia-Liang; Liu, Yan; Zhang, Chun-Li; Tang, Jia-Guang

2015-05-01

Indian Hedgehog (HH) has been shown to be involved in osteoarthritis (OA) in articular joints, where there is evidence that Indian HH blockade could ameliorate OA. It seems to play a prominent role in development of the intervertebral disc (IVD) and in postnatal maintenance. There is little work on IHH in the IVD. Hence the aim of the current study was to investigate the role of Indian Hedgehog in the pathology of facet joint (FJ) OA. 24 patients diagnosed with lumbar intervertebral disk herniation or degenerative spinal stenosis were included. Preoperative magnetic resonance imaging (MRI) and Osteoarthritis Research Society International (OARSI) histopathology grading system was correlated to the mRNA levels of GLI1, PTCH1, and HHIP in the FJs. The Weishaupt grading and OARSI scores showed high positive correlation (r = 0.894) (P < 0.01). MRI Weishaupt grades showed positive correlation with GLI1 (r = 0.491), PTCH1 (r = 0.444), and HHIP (r = 0.654) mRNA levels (P < 0.05 in each case). OARSI scores were also positively correlated with GLI1 (r = 0. 646), PTCH1 (r = 0. 518), and HHIP (r = 0.762) mRNA levels (P < 0.01 in each case). Cumulatively our findings indicate that Indian HH signaling is increased in OA and is perhaps a key component in OA pathogenesis and progression.

Natural Variation in Monoterpene Synthesis in Kiwifruit: Transcriptional Regulation of Terpene Synthases by NAC and ETHYLENE-INSENSITIVE3-Like Transcription Factors1

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Nieuwenhuizen, Niels J.; Chen, Xiuyin; Wang, Mindy Y.; Matich, Adam J.; Perez, Ramon Lopez; Allan, Andrew C.; Green, Sol A.; Atkinson, Ross G.

2015-01-01

Two kiwifruit (Actinidia) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe Actinidia arguta fruit were correlated with increasing gene and protein expression of A. arguta terpene synthase1 (AaTPS1) and correlated with an increase in transcript levels of the 2-C-methyl-d-erythritol 4-phosphate pathway enzyme 1-deoxy-d-xylulose-5-phosphate synthase (DXS). Actinidia chinensis terpene synthase1 (AcTPS1) was identified as part of an array of eight tandemly duplicated genes, and AcTPS1 expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of DXS in Nicotiana benthamiana leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-d-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the AaTPS1 promoter, and cloned members of both TF classes were able to activate the AaTPS1 promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the AaTPS1 promoter but not the A. chinensis AcTPS1 promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe A. chinensis fruit can account for the low accumulation of AcTPS1 transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. PMID:25649633
Diarylheptanoids suppress proliferation of pancreatic cancer PANC-1 cells through modulating shh-Gli-FoxM1 pathway.

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Dong, Guang-Zhi; Jeong, Ji Hye; Lee, Yu-Ih; Lee, So Yoon; Zhao, Hui-Yuan; Jeon, Raok; Lee, Hwa Jin; Ryu, Jae-Ha

2017-04-01

Pancreatic cancer is one of the leading causes of cancer, and it has the lowest 5-year survival rates. It is necessary to develop more potent anti-pancreatic cancer drugs to overcome the fast metastasis and resistance to surgery, radiotherapy, chemotherapy, and combinations of these. We have identified several diarylheptanoids as anti-pancreatic cancer agents from Alpinia officinarum (lesser galangal) and Alnus japonica. These diarylheptanoids suppressed cell proliferation and induced the cell cycle arrest of pancreatic cancer cells (PANC-1). Among them, the most potent compounds 1 and 7 inhibited the shh-Gli-FoxM1 pathway and their target gene expression in PANC-1 cells. Furthermore, they suppressed the expression of the cell cycle associated genes that were rescued by the overexpression of exogenous FoxM1. Taken together, (E)-7-(4-hydroxy-3-methoxyphenyl)-1-phenylhept-4-en-3-one (1) from Alpinia officinarum (lesser galangal) and platyphyllenone (7) from Alnus japonica inhibit PANC-1 cell proliferation by suppressing the shh-Gli-FoxM1 pathway, and they can be potential candidates for anti-pancreatic cancer drug development.
Sp1/Sp3 and DNA-methylation contribute to basal transcriptional activation of human podoplanin in MG63 versus Saos-2 osteoblastic cells

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Puri Christina

2007-03-01

Full Text Available Abstract Background Podoplanin is a membrane mucin that, among a series of tissues, is expressed on late osteoblasts and osteocytes. Since recent findings have focussed on podoplanin's potential role as a tumour progression factor, we aimed at identifying regulatory elements conferring PDPN promoter activity. Here, we characterized the molecular mechanism controlling basal PDPN transcription in human osteoblast-like MG63 versus Saos-2 cells. Results We cloned and sequenced 2056 nucleotides from the 5'-flanking region of the PDPN gene and a computational search revealed that the TATA and CAAT box-lacking promoter possesses features of a growth-related gene, such as a GC-rich 5' region and the presence of multiple putative Sp1, AP-4 and NF-1 sites. Reporter gene assays demonstrated a functional promoter in MG63 cells exhibiting 30-fold more activity than in Saos-2 cells. In vitro DNase I footprinting revealed eight protected regions flanked by DNaseI hypersensitive sites within the region bp -728 to -39 present in MG63, but not in Saos-2 cells. Among these regions, mutation and supershift electrophoretic mobility shift assays (EMSA identified four Sp1/Sp3 binding sites and two binding sites for yet unknown transcription factors. Deletion studies demonstrated the functional importance of two Sp1/Sp3 sites for PDPN promoter activity. Overexpression of Sp1 and Sp3 independently increased the stimulatory effect of the promoter and podoplanin mRNA levels in MG63 and Saos-2 cells. In SL2 cells, Sp3 functioned as a repressor, while Sp1 and Sp3 acted positively synergistic. Weak PDPN promoter activity of Saos-2 cells correlated with low Sp1/Sp3 nuclear levels, which was confirmed by Sp1/Sp3 chromatin immunoprecipitations in vivo. Moreover, methylation-sensitive Southern blot analyses and bisulfite sequencing detected strong methylation of CpG sites upstream of bp -464 in MG63 cells, but hypomethylation of these sites in Saos-2 cells. Concomitantly
STAT3 induces transcription of the DNA methyltransferase 1 gene (DNMT1) in malignant T lymphocytes

DEFF Research Database (Denmark)

Zhang, Qian; Wang, Hong Y; Woetmann, Anders

2006-01-01

In this study, we demonstrated that STAT3, a well-characterized transcription factor expressed in continuously activated oncogenic form in the large spectrum of cancer types, induces in malignant T lymphocytes the expression of DNMT1, the key effector of epigenetic gene silencing. STAT3 binds in ...
Investigation of possible association between Ser9Gly polymorphism of the D3 dopaminergic receptor gene and response to typical antipsychotics in patients with schizophrenia

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Quirino Cordeiro

Full Text Available Typical antipsychotics have a high affinity for dopamine receptors. It is therefore of interest to investigate such loci in pharmacogenetic studies on psychosis. We investigated the hypothesis that Ser9Gly polymorphism of the DRD3 gene may play a role in the differences in individual response to typical antipsychotics between schizophrenic patients. The sample was composed of 53 good responders and 59 poor ones. No significant differences between the good and poor responders were found in the allelic distribution (good responders: Ser9 61.32%, Gly9 38.67%; poor responders: Ser9 64.40%, Gly9 35.59%; odds ratio, OR = 0.88, 0.49 < OR < 1.56; chi2 = 0.23, 1 degree of freedom, df, p = 0.63 and genotype distribution (good responders: Ser9/Ser9 37.73%, Ser9/Gly9 47.16%, Gly9/Gly9 15.09%; poor responders: Ser9/Ser9 42.37%, Ser9/Gly9 44.06%, Gly9/Gly9 13.55%; chi2 = 0.25, 2 df, p = 0.88. Nor was there any association with homozygosity (good responders: homozygous: 52.82%, heterozygous: 47.16%; poor responders: homozygous: 55.92%, heterozygous: 44.06%; odds ratio, OR = 0.88, 0.39 < OR < 1.99; chi2 = 0.11, 1 df, p = 0.74. The results did not support the hypothesis that Ser9Gly polymorphism of the DRD3 gene influences the response to typical antipsychotics in our sample of schizophrenics.
Targeted HIV-1 Latency Reversal Using CRISPR/Cas9-Derived Transcriptional Activator Systems.

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Julia K Bialek

Full Text Available CRISPR/Cas9 technology is currently considered the most advanced tool for targeted genome engineering. Its sequence-dependent specificity has been explored for locus-directed transcriptional modulation. Such modulation, in particular transcriptional activation, has been proposed as key approach to overcome silencing of dormant HIV provirus in latently infected cellular reservoirs. Currently available agents for provirus activation, so-called latency reversing agents (LRAs, act indirectly through cellular pathways to induce viral transcription. However, their clinical performance remains suboptimal, possibly because reservoirs have diverse cellular identities and/or proviral DNA is intractable to the induced pathways. We have explored two CRISPR/Cas9-derived activator systems as targeted approaches to induce dormant HIV-1 proviral DNA. These systems recruit multiple transcriptional activation domains to the HIV 5' long terminal repeat (LTR, for which we have identified an optimal target region within the LTR U3 sequence. Using this target region, we demonstrate transcriptional activation of proviral genomes via the synergistic activation mediator complex in various in culture model systems for HIV latency. Observed levels of induction are comparable or indeed higher than treatment with established LRAs. Importantly, activation is complete, leading to production of infective viral particles. Our data demonstrate that CRISPR/Cas9-derived technologies can be applied to counteract HIV latency and may therefore represent promising novel approaches in the quest for HIV elimination.
Synthesis and structure-activity relationship of N-alkyl Gly-boro-Pro inhibitors of DPP4, FAP, and DPP7.

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Hu, Yi; Ma, Lifu; Wu, Min; Wong, Melissa S; Li, Bei; Corral, Sergio; Yu, Zhizhou; Nomanbhoy, Tyzoon; Alemayehu, Senaiet; Fuller, Stacy R; Rosenblum, Jonathan S; Rozenkrants, Natasha; Minimo, Lauro C; Ripka, William C; Szardenings, Anna K; Kozarich, John W; Shreder, Kevin R

2005-10-01

The structure-activity relationship of various N-alkyl Gly-boro-Pro derivatives against three dipeptidyl peptidases (DPPs) was studied. In a series of N-cycloalkyl analogs, DPP4 and fibroblast activation protein-alpha (FAP) optimally preferred N-cycloheptyl whereas DPP7 tolerated even larger cycloalkyl rings. Gly alpha-carbon derivatization of N-cyclohexyl or N-(2-adamantyl) Gly-boro-Pro resulted in a significant decrease in potency against all the three DPPs.
Peripheral odontogenic keratocyst associated with nevoid basal cell carcinoma syndrome: a case report.

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Sakamoto, Kei; Morita, Kei-Ichi; Shimada, Yasuyuki; Omura, Ken; Izumo, Toshiyuki; Yamaguchi, Akira

2014-07-01

Peripheral odontogenic keratocyst (POKC) is a rare gingival cyst showing histologic features identical to those of keratocystic odontogenic tumor. A rare case of POKC associated with nevoid basal cell carcinoma syndrome (NBCCS) is presented. A 24-year-old woman with NBCCS presented with a pigmented papule, 3 mm in size, involving the lingual gingiva of the right canine area of the mandible. Based on a clinical diagnosis of benign pigmentation, an excisional biopsy was performed, and a histopathologic diagnosis of POKC was rendered. The lining cells were positive for the proteins GLI2, BCL2, keratin 8, keratin 17, and mTOR. TP53 and Ber-EP4 were also weakly positive. Gene mutational analysis on a buccal swab sample revealed 2 missense mutations in the PTCH1 gene. This case is a distinctive example of a genuine soft tissue counterpart of keratocystic odontogenic tumor, in which an aberrant PTCH1-GLI pathway played a considerable role in the pathogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.
IGF-1 induces SOCS-2 but not SOCS-1 and SOCS-3 transcription in juvenile Nile tilapia (Oreochromis niloticus).

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Liu, Cai-Zhi; Luo, Yuan; Limbu, Samwel Mchele; Chen, Li-Qiao; Du, Zhen-Yu

2018-05-20

Insulin-like growth factor-1 (IGF-1) plays a crucial role in regulating growth in vertebrates whereas suppressors of cytokine signaling (SOCS) act as feedback inhibitors of the GH/IGF-1 axis. Although SOCS-2 binds the IGF-1 receptor and inhibits IGF-1-induced STAT3 activation, presently there is no clear evidence as to whether IGF-1 could induce SOCS gene expression. The current study aimed to determine whether IGF-1 could induce the transcription of SOCS in juvenile Nile tilapia ( Oreochromis niloticus ). We show that there is a common positive relationship between the mRNA expression of IGF-I and SOCS-2 under different nutritional statuses and stimulants, but not the mRNA expression of SOCS-1 and SOCS-3 Furthermore, rhIGF-1 treatment and transcriptional activity assay confirmed the hypothesis that IGF-1 could induce SOCS-2 expression, whereas it had no effect or even decreased the expression of SOCS-1 and SOCS-3 Overall, we obtained evidence that the transcription of SOCS-2, but not SOCS-1 or SOCS-3, could be induced by IGF signaling, suggesting that SOCS-2 serves as a feedback suppressor of the IGF-1 axis in juvenile Nile tilapia. © 2018. Published by The Company of Biologists Ltd.
Direct interaction of natural and synthetic catechins with signal transducer activator of transcription 1 affects both its phosphorylation and activity

KAUST Repository

Menegazzi, Marta; Mariotto, Sofia; Dal Bosco, Martina; Darra, Elena; Vaiana, Nadia; Shoji, Kazuo; Safwat, Abdel Azeim; Marechal, Jean Didier; Perahia, David; Suzuki, Hisanori; Romeo, Sergio

2013-01-01

Our previous studies showed that (-)-epigallocatechin-3-gallate (EGCG) inhibits signal transducer activator of transcription 1 (STAT1) activation. Since EGCG may be a promising lead compound for new anti-STAT1 drug design, 15 synthetic catechins
GLI1, a crucial mediator of sonic hedgehog signaling in prostate cancer, functions as a negative modulator for androgen receptor

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Chen, Guangchun; Goto, Yutaka; Sakamoto, Ryuichi; Tanaka, Kimitaka; Matsubara, Eri; Nakamura, Masafumi; Zheng, Hong; Lu, Jian; Takayanagi, Ryoichi; Nomura, Masatoshi

2011-01-01

Research highlights: → GLI1, which play a central role in sonic hedgehog signaling in prostate cancer, can act as a co-repressor to substantially block androgen receptor-mediated transactivation. → GLI1 directly interacts with AR. → SHH-GLI pathway might be one of determinants governing the transition of prostate cancer from an androgen-dependent to an androgen-independent state. -- Abstract: Sonic hedgehog (SHH) signaling, acting in a combinatorial manner with androgen signaling, is essential for prostate patterning and development. Recently, elevated activation of SHH signaling has been shown to play important roles in proliferation, progression and metastasis of prostate cancer. In this report, we demonstrate for the first time, that GLI1, which has been shown to play a central role in SHH signaling in prostate cancer, can act as a co-repressor to substantially block androgen receptor (AR)-mediated transactivation, at least in part, by directly interacting with AR. Our observations suggest that the SHH-GLI pathway might be one of determinants governing the transition of prostate cancer from an androgen-dependent to an androgen-independent state by compensating, or even superseding androgen signaling.
Sp1/3 and NF-1 mediate basal transcription of the human P2X1 gene in megakaryoblastic MEG-01 cells

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Ennion Steven J

2006-03-01

Full Text Available Abstract Background P2X1 receptors play an important role in platelet function as they can induce shape change, granule centralization and are also involved in thrombus formation. As platelets have no nuclei, the level of P2X1 expression depends on transcriptional regulation in megakaryocytes, the platelet precursor cell. Since nothing is known about the molecular mechanisms regulating megakaryocytic P2X1 expression, this study aimed to identify and functionally characterize the P2X1 core promoter utilized in the human megakaryoblastic cell line MEG-01. Results In order to identify cis-acting elements involved in the transcriptional regulation of P2X1 expression, the ability of 4.7 kb P2X1 upstream sequence to drive luciferase reporter gene expression was tested. Low promoter activity was detected in proliferating MEG-01 cells. This activity increased 20-fold after phorbol-12-myristate-13-acetate (PMA induced differentiation. A transcription start site was detected 365 bp upstream of the start codon by primer extension. Deletion analysis of reporter constructs indicated a core promoter located within the region -68 to +149 bp that contained two Sp1 sites (named Sp1a and Sp1b and an NF-1 site. Individual mutations of Sp1b or NF-1 binding sites severely reduced promoter activity whereas triple mutation of Sp1a, Sp1b and NF-1 sites completely abolished promoter activity in both untreated and PMA treated cells. Sp1/3 and NF-1 proteins were shown to bind their respective sites by EMSA and interaction of Sp1/3, NF-1 and TFIIB with the endogenous P2X1 core promoter in MEG-01 cells was demonstrated by chromatin immunoprecipitation. Alignment of P2X1 genes from human, chimp, rat, mouse and dog revealed consensus Sp1a, Sp1b and NF-1 binding sites in equivalent positions thereby demonstrating evolutionary conservation of these functionally important sites. Conclusion This study has identified and characterized the P2X1 promoter utilized in MEG-01 cells and
Trans-activation of the 5' to 3' viral DNA strand transfer by nucleocapsid protein during reverse transcription of HIV1 RNA.

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Darlix, J L; Vincent, A; Gabus, C; de Rocquigny, H; Roques, B

1993-08-01

Two DNA strand transfer reactions take place during reverse transcription of the retroviral genome. The first transfer, that of the minus-strand strong stop DNA from the 5' end of the viral RNA to the 3' end, has been studied in vitro with two RNAs mimicking the 5' and 3' regions of the HIV1 genome and with nucleocapsid protein, NCp7, and reverse transcriptase. The results show that NCp7 strongly activates the 5' to 3' DNA strand transfer during reverse transcription while a basic peptide resembling NCp7 is inactive. Activation of the first transfer by several NCp7 derived peptides and the influence of the terminal redundancies (R) present at the 5' and 3' ends of HIV1 RNA were also examined. The first transfer is optimal in the presence of intact NCp7 and necessitates R on both the 5' and 3' RNAs. Sequencing of full length viral DNA products reveals approximately 40% misincorporations at the first nucleotide beyond the transfer point. If such base misincorporations occur during proviral DNA synthesis with possible homologous recombinations it may well contribute to the high level of genetic variability of HIV.
Identification and Characterization of KCASH2 and KCASH3, 2 Novel Cullin3 Adaptors Suppressing Histone Deacetylase and Hedgehog Activity in Medulloblastoma

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Enrico De Smaele

2011-04-01

Full Text Available Medulloblastoma is the most common pediatric malignant brain tumor, arising from aberrant cerebellar precursors' development, a process mainly controlled by Hedgehog (Hh signaling pathway. Histone deacetylase HDAC1 has been recently shown to modulate Hh signaling, deacetylating its effectors Gli1/2 and enhancing their transcriptional activity. Therefore, HDAC may represent a potential therapeutic target for Hh-dependent tumors, but still little information is available on the physiological mechanisms of HDAC regulation. The putative tumor suppressor RENKCTD11 acts through ubiquitination-dependent degradation of HDAC1, thereby affecting Hh activity and medulloblastoma growth. We identify and characterize here two RENKCTD11 homologues, defining a new family of proteins named KCASH, as “KCTD containing, Cullin3 adaptor, suppressor of Hedgehog.” Indeed, the novel genes (KCASH2KCTD21 and KCASH3KCTD6 share with RENKCTD11 a number of features, such as a BTB domain required for the formation of a Cullin3 ubiquitin ligase complex and HDAC1 ubiquitination and degradation capability, suppressing the acetylation-dependent Hh/Gli signaling. Expression of KCASH2 and -3 is observed in cerebellum, whereas epigenetic silencing and allelic deletion are observed in human medulloblastoma. Rescuing KCASHs expression reduces the Hedgehog-dependent medulloblastoma growth, suggesting that loss of members of this novel family of native HDAC inhibitors is crucial in sustaining Hh pathway-mediated tumorigenesis. Accordingly, they might represent a promising class of endogenous “agents” through which this pathway may be targeted.
Transcriptional activation of peroxisome proliferator-activated receptor-γ requires activation of both protein kinase A and Akt during adipocyte differentiation

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Kim, Sang-pil; Ha, Jung Min; Yun, Sung Ji; Kim, Eun Kyoung; Chung, Sung Woon; Hong, Ki Whan; Kim, Chi Dae; Bae, Sun Sik

2010-01-01

Research highlights: → Elevated cAMP activates both PKA and Epac. → PKA activates CREB transcriptional factor and Epac activates PI3K/Akt pathway via Rap1. → Akt modulates PPAR-γ transcriptional activity in concert with CREB. -- Abstract: Peroxisome proliferator-activated receptor-γ (PPAR-γ) is required for the conversion of pre-adipocytes. However, the mechanism underlying activation of PPAR-γ is unclear. Here we showed that cAMP-induced activation of protein kinase A (PKA) and Akt is essential for the transcriptional activation of PPAR-γ. Hormonal induction of adipogenesis was blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), by a protein kinase A (PKA) inhibitor (H89), and by a Rap1 inhibitor (GGTI-298). Transcriptional activity of PPAR-γ was markedly enhanced by 3-isobutyl-1-methylxanthine (IBMX), but not insulin and dexamethasone. In addition, IBMX-induced PPAR-γ transcriptional activity was blocked by PI3K/Akt, PKA, or Rap1 inhibitors. 8-(4-Chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT-2'-O-Me-cAMP) which is a specific agonist for exchanger protein directly activated by cAMP (Epac) significantly induced the activation of Akt. Furthermore, knock-down of Akt1 markedly attenuated PPAR-γ transcriptional activity. These results indicate that both PKA and Akt signaling pathways are required for transcriptional activation of PPAR-γ, suggesting post-translational activation of PPAR-γ might be critical step for adipogenic gene expression.
Association of expression of the hedgehog signal with Merkel cell polyomavirus infection and prognosis of Merkel cell carcinoma.

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Kuromi, Teruyuki; Matsushita, Michiko; Iwasaki, Takeshi; Nonaka, Daisuke; Kuwamoto, Satoshi; Nagata, Keiko; Kato, Masako; Akizuki, Gen; Kitamura, Yukisato; Hayashi, Kazuhiko

2017-11-01

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer that mostly occurs in the elderly. Merkel cell polyomavirus (MCPyV) is detected in approximately 80% of MCCs and is associated with carcinogenesis. Hedgehog signaling pathway plays a role in human embryogenesis and organogenesis. In addition, reactivation of this pathway later in life can cause tumors. Twenty-nineMCPyV-positive and 21 MCPyV-negative MCCs were immunohistochemically stained with primary antibodies for hedgehog signaling (SHH, IHH, PTCH1, SMO, GLI1, GLI2, and GLI3) and evaluated using H-score. Polymerase chain reaction and sequence analysis for SHH and GLI1 exons were also performed. Expression of SHH was higher in MCPyV-positive MCCs than in MCPyV-negative MCCs (PA. Only 2 mutations with amino acid changes were detected in MCPyV-negative MCCs only: 1 missense mutation in GLI1 exon 4 and 1 nonsense mutation in SHH-3B. Expression of SHH and GLI1 may be useful prognostic markers of MCC because increased expression was associated with better prognosis. The high rate of c.576G>A silent mutation in GLI1 exon 5 was a feature of MCC. Copyright © 2017 Elsevier Inc. All rights reserved.
Assessment of airborne soy-hull allergen (Gly m 1) in the Port of Ancona, Italy.

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Antonicelli, L; Ruello, M L; Monsalve, R I; González, R; Fava, G; Bonifazi, F

2010-10-01

Epidemic asthma outbreaks are potentially a very high-risk medical situation in seaport towns where large volumes of soybean are loaded and unloaded Airborne allergen assessment plays a pivotal role in evaluating the resulting environmental pollution. The aim of this study was to measure the airborne Gly m 1 allergen level in the seaport of Ancona in order assess the soybean-specific allergenic risk for the city. Allergen and PM10 were evaluated at progressive distances from the port area. Allergen analysis was performed by monoclonal antibody-based immunoassay on the sampled filters. Daily meteorological data were obtained from the local meteorological station. For estimating the assimilative capacity of the atmosphere, an approach based on dispersive ventilation coefficient was tried. The allergen concentrations detected were low (range = 0.4-171 ng/m3). A decreasing gradient of the airborne allergen from the unloading area (22.1 +/- 41.2 ng/m3) to the control area (0.6 +/- 0.7 ng/m3) was detected. The concentration of the airborne Gly m 1 was not coupled with the presence of the soy-carrying ships in the port. A statistically significant relationship between airborne allergen, PM10 and local meteorological parameters quantifies the association with the atmospheric condition. Airborne Gly m 1 is part of the atmospheric dust of Ancona. The low level of this allergen seems consistent with the absence of asthma epidemic outbreak.
Reconstruction of the gene regulatory network involved in the sonic hedgehog pathway with a potential role in early development of the mouse brain.

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Jinhua Liu

2014-10-01

Full Text Available The Sonic hedgehog (Shh signaling pathway is crucial for pattern formation in early central nervous system development. By systematically analyzing high-throughput in situ hybridization data of E11.5 mouse brain, we found that Shh and its receptor Ptch1 define two adjacent mutually exclusive gene expression domains: Shh+Ptch1- and Shh-Ptch1+. These two domains are associated respectively with Foxa2 and Gata3, two transcription factors that play key roles in specifying them. Gata3 ChIP-seq experiments and RNA-seq assays on Gata3-knockdown cells revealed that Gata3 up-regulates the genes that are enriched in the Shh-Ptch1+ domain. Important Gata3 targets include Slit2 and Slit3, which are involved in the process of axon guidance, as well as Slc18a1, Th and Qdpr, which are associated with neurotransmitter synthesis and release. By contrast, Foxa2 both up-regulates the genes expressed in the Shh+Ptch1- domain and down-regulates the genes characteristic of the Shh-Ptch1+ domain. From these and other data, we were able to reconstruct a gene regulatory network governing both domains. Our work provides the first genome-wide characterization of the gene regulatory network involved in the Shh pathway that underlies pattern formation in the early mouse brain.
Analysis of signal transducer and activator of transcription 3 (Stat 3) pathway in multiple myeloma: Stat 3 activation and cyclin D1 dysregulation are mutually exclusive events.

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Quintanilla-Martinez, Leticia; Kremer, Marcus; Specht, Katja; Calzada-Wack, Julia; Nathrath, Michaela; Schaich, Robert; Höfler, Heinz; Fend, Falko

2003-05-01

The signal transducer and activator of transcription molecules (Stats) play key roles in cytokine-induced signal transduction. Recently, it was proposed that constitutively activated Stat 3 (Stat 3 phosphorylated) contributes to the pathogenesis of multiple myeloma (MM) by preventing apoptosis and inducing proliferation. The study aim was to investigate Stat 3 activation in a series of multiple myeloma (MM) cases and its effect on downstream targets such as the anti-apoptotic proteins Bcl-xL, Mcl-1, and Bcl-2, and the cell-cycle protein cyclin D1. Forty-eight cases of MM were analyzed. Immunohistochemistry was performed on paraffin sections using antibodies against cyclin D1, Bcl-2, Bcl-xL, Mcl-1, p21, Stat 3, and Stat 3 phosphorylated (P). Their specificity was corroborated by Western blot analysis using eight human MM cell lines as control. The proliferation rate was assessed with the antibody MiB1. In addition, the mRNA levels of cyclin D1 and Stat 3 were determined by quantitative real-time reverse transcriptase-polymerase chain reaction of paraffin-embedded microdissected tissue. Three different groups determined by the expression of Stat 3P and cyclin D1 (protein and mRNA) were identified: group 1, Stat 3-activated (23 cases, 48%). All cases revealed nuclear expression of Stat 3P. No elevation of Stat 3 mRNA was identified in any of the cases. Three cases in this group showed intermediate to low cyclin D1 protein and mRNA expression. Group 2 included 15 (31%) cases with cyclin D1 staining and lack of Stat 3P. All cases showed intermediate to high levels of cyclin D1 mRNA expression. Group 3 included 10 (21%) cases with no expression of either cyclin D1 or Stat 3P. High levels of anti-apoptotic proteins Bcl-xL and Mcl-1 were identified in 89% and 100% of all cases, respectively. In contrast to Bcl-xL and Mcl-1, the expression of Bcl-2 showed an inverse correlation with proliferation rate (P: 0.0003). No significant differences were found between the three
The Role of the PGC1α Gly482Ser Polymorphism in Weight Gain due to Intensive Diabetes Therapy

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Samir S. Deeb

2009-01-01

Full Text Available The Diabetes Control and Complications Trial (DCCT involved intensive diabetes therapy of subjects with type 1 diabetes mellitus (T1DM for an average period of 6.5 years. A subset of these subjects gained excessive weight. We tested for association of polymorphisms in 8 candidate genes with the above trait. We found the Gly482Ser polymorphism in the peroxisome proliferator-activated receptor γ coactivator-1α (PGC1α to be significantly associated with weight gain in males (P=.0045 but not in females. The Ser allele was associated with greater weight gain than the Gly allele (P=.005. Subjects with a family history of type 2 diabetes mellitus (T2DM were more common among those who gained excessive weight. We conclude that T2DM and the Gly482Ser polymorphism in PGC1α contribute to the effect of intensive diabetes therapy on weight gain in males with T1DM.

Non-Canonical Hedgehog Signaling Is a Positive Regulator of the WNT Pathway and Is Required for the Survival of Colon Cancer Stem Cells

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Joseph L. Regan

2017-12-01

Full Text Available Summary: Colon cancer is a heterogeneous tumor driven by a subpopulation of cancer stem cells (CSCs. To study CSCs in colon cancer, we used limiting dilution spheroid and serial xenotransplantation assays to functionally define the frequency of CSCs in a panel of patient-derived cancer organoids. These studies demonstrated cancer organoids to be enriched for CSCs, which varied in frequency between tumors. Whole-transcriptome analysis identified WNT and Hedgehog signaling components to be enhanced in CSC-enriched tumors and in aldehyde dehydrogenase (ALDH-positive CSCs. Canonical GLI-dependent Hedgehog signaling is a negative regulator of WNT signaling in normal intestine and intestinal tumors. Here, we show that Hedgehog signaling in colon CSCs is autocrine SHH-dependent, non-canonical PTCH1 dependent, and GLI independent. In addition, using small-molecule inhibitors and RNAi against SHH-palmitoylating Hedgehog acyltransferase (HHAT, we demonstrate that non-canonical Hedgehog signaling is a positive regulator of WNT signaling and required for colon CSC survival. : Colon cancer is a heterogeneous tumor driven by a subpopulation(s of therapy-resistant cancer stem cells (CSCs. Regan et al. use 3D culture models to demonstrate that CSC survival is regulated by non-canonical, SHH-dependent, PTCH1-dependent Hedgehog signaling, which acts as a positive regulator of WNT signaling to block CSC differentiation. Keywords: WNT pathway, non-canonical Hedgehog signaling, cancer stem cell, colon cancer, cancer organoid, PTCH1, HHAT, SHH
MAML1 enhances the transcriptional activity of Runx2 and plays a role in bone development.

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Takashi Watanabe

Full Text Available Mastermind-like 1 (MAML1 is a transcriptional co-activator in the Notch signaling pathway. Recently, however, several reports revealed novel and unique roles for MAML1 that are independent of the Notch signaling pathway. We found that MAML1 enhances the transcriptional activity of runt-related transcription factor 2 (Runx2, a transcription factor essential for osteoblastic differentiation and chondrocyte proliferation and maturation. MAML1 significantly enhanced the Runx2-mediated transcription of the p6OSE2-Luc reporter, in which luciferase expression was controlled by six copies of the osteoblast specific element 2 (OSE2 from the Runx2-regulated osteocalcin gene promoter. Interestingly, a deletion mutant of MAML1 lacking the N-terminal Notch-binding domain also enhanced Runx2-mediated transcription. Moreover, inhibition of Notch signaling did not affect the action of MAML1 on Runx2, suggesting that the activation of Runx2 by MAML1 may be caused in a Notch-independent manner. Overexpression of MAML1 transiently enhanced the Runx2-mediated expression of alkaline phosphatase, an early marker of osteoblast differentiation, in the murine pluripotent mesenchymal cell line C3H10T1/2. MAML1(-/- embryos at embryonic day 16.5 (E16.5 had shorter bone lengths than wild-type embryos. The area of primary spongiosa of the femoral diaphysis was narrowed. At E14.5, extended zone of collagen type II alpha 1 (Col2a1 and Sox9 expression, markers of chondrocyte differentiation, and decreased zone of collagen type X alpha 1 (Col10a1 expression, a marker of hypertrophic chondrocyte, were observed. These observations suggest that chondrocyte maturation was impaired in MAML1(-/- mice. MAML1 enhances the transcriptional activity of Runx2 and plays a role in bone development.
The metal-responsive transcription factor-1 contributes to HIF-1 activation during hypoxic stress

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Murphy, Brian J.; Sato, Barbara G.; Dalton, Timothy P.; Laderoute, Keith R.

2005-01-01

Hypoxia-inducible factor-1 (HIF-1), the major transcriptional regulator of the mammalian cellular response to low oxygen (hypoxia), is embedded within a complex network of signaling pathways. We have been investigating the importance of another stress-responsive transcription factor, MTF-1, for the adaptation of cells to hypoxia. This article reports that MTF-1 plays a central role in hypoxic cells by contributing to HIF-1 activity. Loss of MTF-1 in transformed Mtf1 null mouse embryonic fibroblasts (MEFs) results in an attenuation of nuclear HIF-1α protein accumulation, HIF-1 transcriptional activity, and expression of an established HIF-1 target gene, glucose transporter-1 (Glut1). Mtf1 null (Mtf1 KO) MEFs also have constitutively higher levels of both glutathione (GSH) and the rate-limiting enzyme involved in GSH synthesis-glutamate cysteine ligase catalytic subunit-than wild type cells. The altered cellular redox state arising from increased GSH may perturb oxygen-sensing mechanisms in hypoxic Mtf1 KO cells and decrease the accumulation of HIF-1α protein. Together, these novel findings define a role for MTF-1 in the regulation of HIF-1 activity
Controlling cellular P-TEFb activity by the HIV-1 transcriptional transactivator Tat.

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Lisa Muniz

Full Text Available The human immunodeficiency virus 1 (HIV-1 transcriptional transactivator (Tat is essential for synthesis of full-length transcripts from the integrated viral genome by RNA polymerase II (Pol II. Tat recruits the host positive transcription elongation factor b (P-TEFb to the HIV-1 promoter through binding to the transactivator RNA (TAR at the 5'-end of the nascent HIV transcript. P-TEFb is a general Pol II transcription factor; its cellular activity is controlled by the 7SK small nuclear RNA (snRNA and the HEXIM1 protein, which sequester P-TEFb into transcriptionally inactive 7SK/HEXIM/P-TEFb snRNP. Besides targeting P-TEFb to HIV transcription, Tat also increases the nuclear level of active P-TEFb through promoting its dissociation from the 7SK/HEXIM/P-TEFb RNP by an unclear mechanism. In this study, by using in vitro and in vivo RNA-protein binding assays, we demonstrate that HIV-1 Tat binds with high specificity and efficiency to an evolutionarily highly conserved stem-bulge-stem motif of the 5'-hairpin of human 7SK snRNA. The newly discovered Tat-binding motif of 7SK is structurally and functionally indistinguishable from the extensively characterized Tat-binding site of HIV TAR and importantly, it is imbedded in the HEXIM-binding elements of 7SK snRNA. We show that Tat efficiently replaces HEXIM1 on the 7SK snRNA in vivo and therefore, it promotes the disassembly of the 7SK/HEXIM/P-TEFb negative transcriptional regulatory snRNP to augment the nuclear level of active P-TEFb. This is the first demonstration that HIV-1 specifically targets an important cellular regulatory RNA, most probably to promote viral transcription and replication. Demonstration that the human 7SK snRNA carries a TAR RNA-like Tat-binding element that is essential for the normal transcriptional regulatory function of 7SK questions the viability of HIV therapeutic approaches based on small drugs blocking the Tat-binding site of HIV TAR.
Obesity is associated with the Arg389Gly ADRB1 but not with the Trp64Arg ADRB3 polymorphism in children from San Luis PotosÍ and León, México.

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Aradillas-Garc X Cd, Celia; Cruz, Miguel; Pérez-Luque, Elva; Garay-Sevilla, María E; Malacara, Juan M; R, Aduna; Peralta, Jesús; Burguete-García, Ana; Alegría-Torres, Jorge A

2016-10-17

This research was designed to analyze the possible associations of Arg389Gly ADRB1 and Trp64Arg ADRB3 polymorphisms in children with obesity. A cross-sectional study included 1,046 school-age Mexican participants (6-12 years old) from the cities of San Luis PotosÍ and León. Children were classified as non-obese or obese according to their body mass index (BMI) percentile; obese children had a BMI≥95th percentile for sex and age. Biochemical data were collected. Polymorphisms were detected using TaqMan qPCR assay. A logistic regression analysis was used to calculate the risk of obesity based on genotypes. Differences were found between groups where obese children had a significant increase in systolic and diastolic blood pressure, fasting plasma glucose, insulin, HOMA-IR, LDL-cholesterol, triglycerides, and lower HDL-cholesterol compared with the normal weight group (P<0.05). The distribution of allele frequency in the population was Arg= 87.4 and Gly= 12.6 (Hardy Weinberg equilibrium c 2 = 3.16 , P = 0.07 ); Trp= 81.5 and Arg= 18.5 (Hardy Weinberg equilibrium c 2 = 2.2, P = 0.14 ) for ADRB1 and ADRB3, respectively. Even though no different frequencies of Arg389Gly polymorphism between groups were found (P = 0.08), children carriers of one Gly389 ADRB1 allele had a risk for obesity of OR=1.40 (95%CI, 1.03-1.90, P = 0.03) after adjustment for age and gender. No other association was found for Trp64Arg ADRB3 polymorphism. Only the Arg389Gly ADRB1 polymorphism was associated with risk for obesity in Mexican children.
PI3K/AKT signaling modulates transcriptional expression of EWS/FLI1 through specificity protein 1.

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Giorgi, Chiara; Boro, Aleksandar; Rechfeld, Florian; Lopez-Garcia, Laura A; Gierisch, Maria E; Schäfer, Beat W; Niggli, Felix K

2015-10-06

Ewing sarcoma (ES) is the second most frequent bone cancer in childhood and is characterized by the presence of the balanced translocation t(11;22)(q24;q12) in more than 85% of cases, generating a dysregulated transcription factor EWS/FLI1. This fusion protein is an essential oncogenic component of ES development which is necessary for tumor cell maintenance and represents an attractive therapeutic target. To search for modulators of EWS/FLI1 activity we screened a library of 153 targeted compounds and identified inhibitors of the PI3K pathway to directly modulate EWS/FLI1 transcription. Surprisingly, treatment of four different ES cell lines with BEZ235 resulted in down regulation of EWS/FLI1 mRNA and protein by ~50% with subsequent modulation of target gene expression. Analysis of the EWS/FLI1 promoter region (-2239/+67) using various deletion constructs identified two 14 bp minimal elements as being important for EWS/FLI1 transcription. We identified SP1 as modulator of EWS/FLI1 gene expression and demonstrated direct binding to one of these regions in the EWS/FLI1 promoter by EMSA and ChIP experiments. These results provide the first insights on the transcriptional regulation of EWS/FLI1, an area that has not been investigated so far, and offer an additional molecular explanation for the known sensitivity of ES cell lines to PI3K inhibition.
RKIP phosphorylation–dependent ERK1 activation stimulates adipogenic lipid accumulation in 3T3-L1 preadipocytes overexpressing LC3

Energy Technology Data Exchange (ETDEWEB)

Hahm, Jong Ryeal [Department of Internal Medicine, Gyeongsang National University School of Medicine, JinJu, 527-27 (Korea, Republic of); Institute of Health Sciences, Gyeongsang National University School of Medicine, JinJu, 527-27 (Korea, Republic of); Ahmed, Mahmoud [Department of Biochemistry and Convergence Medical Science, Gyeongsang National University School of Medicine, JinJu, 527-27 (Korea, Republic of); Institute of Health Sciences, Gyeongsang National University School of Medicine, JinJu, 527-27 (Korea, Republic of); Kim, Deok Ryong, E-mail: drkim@gnu.ac.kr [Department of Biochemistry and Convergence Medical Science, Gyeongsang National University School of Medicine, JinJu, 527-27 (Korea, Republic of); Institute of Health Sciences, Gyeongsang National University School of Medicine, JinJu, 527-27 (Korea, Republic of)

2016-09-09

3T3-L1 preadipocytes undergo adipogenesis in response to treatment with dexamethaxone, 1-methyl-3-isobutylxanthine, and insulin (DMI) through activation of several adipogenic transcription factors. Many autophagy-related proteins are also highly activated in the earlier stages of adipogenesis, and the LC3 conjugation system is required for formation of lipid droplets. Here, we investigated the effect of overexpression of green fluorescent protein (GFP)-LC3 fusion protein on adipogenesis. Overexpression of GFP-LC3 in 3T3-L1 preadipocytes using poly-L-lysine-assisted adenoviral GFP-LC3 transduction was sufficient to produce intracellular lipid droplets. Indeed, GFP-LC3 overexpression stimulated expression of some adipogenic transcription factors (e.g., C/EBPα or β, PPARγ, SREBP2). In particular, SREBP2 was highly activated in preadipocytes transfected with adenoviral GFP-LC3. Also, phosphorylation of Raf kinase inhibitory protein (RKIP) at serine 153, consequently stimulating extracellular-signal regulated kinase (ERK)1 activity, was significantly increased during adipogenesis induced by either poly-L-lysine-assisted adenoviral GFP-LC3 transduction or culture in the presence of dexamethasone, 1-methyl-3-isobutylxanthine, and insulin. Furthermore, RKIP knockdown promoted ERK1 and PPARγ activation, and significantly increased the intracellular accumulation of triacylglycerides in DMI-induced adipogenesis. In conclusion, GFP-LC3 overexpression in 3T3-L1 preadipocytes stimulates adipocyte differentiation via direct modulation of RKIP-dependent ERK1 activity. - Highlights: • Overexpression of GFP-LC3 in 3T3-L1 cells produces intracellular lipid droplets. • SREBP2 is highly activated in preadipocytes transfected with adenoviral GFP-LC3. • RKIP phosphorylation at serine 153 is significantly increased during adipogenesis. • RKIP knockdown promotes ERK1 and PPARγ activation during adipogenesis. • RKIP-dependent ERK1 activation increases triacylglycerides in
Activation of anthocyanin biosynthesis by expression of the radish R2R3-MYB transcription factor gene RsMYB1.

Science.gov (United States)

Lim, Sun-Hyung; Song, Ji-Hye; Kim, Da-Hye; Kim, Jae Kwang; Lee, Jong-Yeol; Kim, Young-Mi; Ha, Sun-Hwa

2016-03-01

RsMYB1, a MYB TF of red radish origin, was characterized as a positive regulator to transcriptionally activate the anthocyanin biosynthetic machinery by itself in Arabidopsis and tobacco plants. Anthocyanins, providing the bright red-orange to blue-violet colors, are flavonoid-derived pigments with strong antioxidant activity that have benefits for human health. We isolated RsMYB1, which encodes an R2R3-MYB transcription factor (TF), from red radish plants (Raphanus sativus L.) that accumulate high levels of anthocyanins. RsMYB1 shows higher expression in red radish than in common white radish, in both leaves and roots, at different growth stages. Consistent with RsMYB1 function as an anthocyanin-promoting TF, red radishes showed higher expression of all six anthocyanin biosynthetic and two anthocyanin regulatory genes. Transient expression of RsMYB1 in tobacco showed that RsMYB1 is a positive regulator of anthocyanin production with better efficiency than the basic helix-loop-helix (bHLH) TF gene B-Peru. Also, the synergistic effect of RsMYB1 with B-Peru was larger than the effect of the MYB TF gene mPAP1D with B-peru. Arabidopsis plants stably expressing RsMYB1 produced red pigmentation throughout the plant, accompanied by up-regulation of the six structural and two regulatory genes for anthocyanin production. This broad transcriptional activation of anthocyanin biosynthetic machinery in Arabidopsis included up-regulation of TRANSPARENT TESTA8, which encodes a bHLH TF. These results suggest that overexpression of RsMYB1 promotes anthocyanin production by triggering the expression of endogenous bHLH genes as potential binding partners for RsMYB1. In addition, RsMYB1-overexpressing Arabidopsis plants had a higher antioxidant capacity than did non-transgenic control plants. Taken together, RsMYB1 is an actively positive regulator for anthocyanins biosynthesis in radish plants and it might be one of the best targets for anthocyanin production by single gene
A novel PTCH1 gene mutation in a pediatric patient associated multiple keratocystic odontogenic tumors of the jaws and Gorlin-Goltz syndrome.

Science.gov (United States)

Ozcan, Gozde; Balta, Burhan; Sekerci, Ahmet Ercan; Etoz, Osman A; Martinuzzi, Claudia; Kara, Ozlem; Pastorino, Lorenza; Kocoglu, Fatma; Ulker, Omer; Erdogan, Murat

2016-01-01

Gorlin-Goltz syndrome (GGS) is an uncommon autosomal dominant inherited disorder which comprises the triad of basal cell carcinomas (BCCs), odontogenic keratocysts, and musculoskeletal malformations. Besides this triad, neurological, ophthalmic, endocrine, and genital manifestations are known to be variable. It is occasionally associated with aggressive BCC and internal malignancies. This report documents a case of GGS with a novel mutation in the PTCH1 gene in an 11-year-old child. The clinical, radiographic, histopathologic and molecular findings of this condition, and treatment are described, and a review of GGS was carried out.
Basal cell carcinoma preferentially arises from stem cells within hair follicle and mechanosensory niches.

Science.gov (United States)

Peterson, Shelby C; Eberl, Markus; Vagnozzi, Alicia N; Belkadi, Abdelmadjid; Veniaminova, Natalia A; Verhaegen, Monique E; Bichakjian, Christopher K; Ward, Nicole L; Dlugosz, Andrzej A; Wong, Sunny Y

2015-04-02

Basal cell carcinoma (BCC) is characterized by frequent loss of PTCH1, leading to constitutive activation of the Hedgehog pathway. Although the requirement for Hedgehog in BCC is well established, the identity of disease-initiating cells and the compartments in which they reside remain controversial. By using several inducible Cre drivers to delete Ptch1 in different cell compartments in mice, we show here that multiple hair follicle stem cell populations readily develop BCC-like tumors. In contrast, stem cells within the interfollicular epidermis do not efficiently form tumors. Notably, we observed that innervated Gli1-expressing progenitors within mechanosensory touch dome epithelia are highly tumorigenic. Sensory nerves activate Hedgehog signaling in normal touch domes, while denervation attenuates touch dome-derived tumors. Together, our studies identify varying tumor susceptibilities among different stem cell populations in the skin, highlight touch dome epithelia as "hot spots" for tumor formation, and implicate cutaneous nerves as mediators of tumorigenesis. Copyright © 2015 Elsevier Inc. All rights reserved.
Domestic allergens; Gli allergeni domestici

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Bressa, G. [Padua Univ., Padua (Italy). DIpt. di Tossicologia Ambientale

2000-12-01

Closed rooms can be the ideal habitat for the growth of many micro-organisms, some of which pathogenic for man. Indoor biologic contamination sources can vary: 1) external air can, through dust particles or water droplets, transfer a large number of germs inside the house; 2) air conditioning plants can become, if maintenance isn't carried out at regular intervals, a cultural medium for microbes which later spread to the air of house or office; 3) the presence of sick people or healthy carriers of pathogenic germs in closed rooms can represent a significant source of biologic contamination; 4) lastly, pets too can be considered as disease carriers. Particularly interesting is the so-called biologic dust - where mites proliferate - which, being trapped in curtains, carpeting, tapestry, fabrics and carpets, often causes respiratory system diseases. [Italian] Gli ambienti chiusi possono costituire l'habita ideale per la crescita di molti microorganismi, alcuni dei quali patogeni per l'uomo. Le fonti di contaminaizone biologica indoor possono essere diverse: 1) l'aria esterna puo' trasferire all'interno, attraverso particelle di polvere o goccioline d'acqua, un gran numero di germi; 2) gli impianti di condizionamento possono divenire, quando non si effettua una corretta manutenzione periodica, terreno di coltura di microbi che successivamente si diffondono nell'aria dell'abitazione o dell'ufficio; 3) la presenza in locali chiusi di persone malate o portatrici sane di germi patogeni puo' costituire un'importante sorgente di contaminazione biologica; 4) infine anche gli animali domestici possono essere considerati vettori di malattie. Di particolare interesse sono le polveri cosidette biologiche, in cui proliferano gli acari, che, essendo trattenute da tendaggi, parati, moquette, tessuti e tappeti, provocano frequentemente malattie dell'apparato respiratorio.
New PAH gene promoter KLF1 and 3'-region C/EBPalpha motifs influence transcription in vitro.

Science.gov (United States)

Klaassen, Kristel; Stankovic, Biljana; Kotur, Nikola; Djordjevic, Maja; Zukic, Branka; Nikcevic, Gordana; Ugrin, Milena; Spasovski, Vesna; Srzentic, Sanja; Pavlovic, Sonja; Stojiljkovic, Maja

2017-02-01

Phenylketonuria (PKU) is a metabolic disease caused by mutations in the phenylalanine hydroxylase (PAH) gene. Although the PAH genotype remains the main determinant of PKU phenotype severity, genotype-phenotype inconsistencies have been reported. In this study, we focused on unanalysed sequences in non-coding PAH gene regions to assess their possible influence on the PKU phenotype. We transiently transfected HepG2 cells with various chloramphenicol acetyl transferase (CAT) reporter constructs which included PAH gene non-coding regions. Selected non-coding regions were indicated by in silico prediction to contain transcription factor binding sites. Furthermore, electrophoretic mobility shift assay (EMSA) and supershift assays were performed to identify which transcriptional factors were engaged in the interaction. We found novel KLF1 motif in the PAH promoter, which decreases CAT activity by 50 % in comparison to basal transcription in vitro. The cytosine at the c.-170 promoter position creates an additional binding site for the protein complex involving KLF1 transcription factor. Moreover, we assessed for the first time the role of a multivariant variable number tandem repeat (VNTR) region located in the 3'-region of the PAH gene. We found that the VNTR3, VNTR7 and VNTR8 constructs had approximately 60 % of CAT activity. The regulation is mediated by the C/EBPalpha transcription factor, present in protein complex binding to VNTR3. Our study highlighted two novel promoter KLF1 and 3'-region C/EBPalpha motifs in the PAH gene which decrease transcription in vitro and, thus, could be considered as PAH expression modifiers. New transcription motifs in non-coding regions will contribute to better understanding of the PKU phenotype complexity and may become important for the optimisation of PKU treatment.
Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

International Nuclear Information System (INIS)

Sahu, Geetaram; Farley, Kalamo; El-Hage, Nazira; Aiamkitsumrit, Benjamas; Fassnacht, Ryan; Kashanchi, Fatah; Ochem, Alex; Simon, Gary L.; Karn, Jonathan; Hauser, Kurt F.; Tyagi, Mudit

2015-01-01

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-ĸB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-ĸB at 276th serine residue. These modifications enhance the interaction of NF-ĸB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication. - Highlights: • Cocaine induces the initiation phase of HIV transcription by activating NF-ĸB. • Cocaine induced NF-ĸB phosphorylation promotes its interaction with P300. • Cocaine enhances the elongation phase of HIV transcription by stimulating MSK1. • Cocaine activated MSK1 catalyzes the phosphorylation of histone H3 at its Ser10. • Cocaine induced H3S10 phosphorylation facilitates the recruitment of P-TEFb at LTR
Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

Energy Technology Data Exchange (ETDEWEB)

Sahu, Geetaram; Farley, Kalamo [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); El-Hage, Nazira [Virginia Commonwealth University, Richmond, VA (United States); Aiamkitsumrit, Benjamas; Fassnacht, Ryan [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); Kashanchi, Fatah [George Mason University, Manassas, VA (United States); Ochem, Alex [ICGEB, Wernher and Beit Building, Anzio Road, Observatory, 7925 Cape Town (South Africa); Simon, Gary L. [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); Karn, Jonathan [Case Western Reserve University, Cleveland, OH (United States); Hauser, Kurt F. [Virginia Commonwealth University, Richmond, VA (United States); Tyagi, Mudit, E-mail: tmudit@email.gwu.edu [Division of Infectious Diseases, Department of Medicine, George Washington University, Washington, DC (United States); Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington, DC 20037 (United States)

2015-09-15

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-ĸB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-ĸB at 276th serine residue. These modifications enhance the interaction of NF-ĸB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication. - Highlights: • Cocaine induces the initiation phase of HIV transcription by activating NF-ĸB. • Cocaine induced NF-ĸB phosphorylation promotes its interaction with P300. • Cocaine enhances the elongation phase of HIV transcription by stimulating MSK1. • Cocaine activated MSK1 catalyzes the phosphorylation of histone H3 at its Ser10. • Cocaine induced H3S10 phosphorylation facilitates the recruitment of P-TEFb at LTR.
Abscisic acid-dependent multisite phosphorylation regulates the activity of a transcription activator AREB1.

Science.gov (United States)

Furihata, Takashi; Maruyama, Kyonoshin; Fujita, Yasunari; Umezawa, Taishi; Yoshida, Riichiro; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2006-02-07

bZIP-type transcription factors AREBs/ABFs bind an abscisic acid (ABA)-responsive cis-acting element named ABRE and transactivate downstream gene expression in Arabidopsis. Because AREB1 overexpression could not induce downstream gene expression, activation of AREB1 requires ABA-dependent posttranscriptional modification. We confirmed that ABA activated 42-kDa kinase activity, which, in turn, phosphorylated Ser/Thr residues of R-X-X-S/T sites in the conserved regions of AREB1. Amino acid substitutions of R-X-X-S/T sites to Ala suppressed transactivation activity, and multiple substitution of these sites resulted in almost complete suppression of transactivation activity in transient assays. In contrast, substitution of the Ser/Thr residues to Asp resulted in high transactivation activity without exogenous ABA application. A phosphorylated, transcriptionally active form was achieved by substitution of Ser/Thr in all conserved R-X-X-S/T sites to Asp. Transgenic plants overexpressing the phosphorylated active form of AREB1 expressed many ABA-inducible genes, such as RD29B, without ABA treatment. These results indicate that the ABA-dependent multisite phosphorylation of AREB1 regulates its own activation in plants.
Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance.

Science.gov (United States)

Liu, Hong Xiang; Ermilov, Alexandre; Grachtchouk, Marina; Li, Libo; Gumucio, Deborah L; Dlugosz, Andrzej A; Mistretta, Charalotte M

2013-10-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste
A novel PTCH1 gene mutation in a pediatric patient associated multiple keratocystic odontogenic tumors of the jaws and Gorlin–Goltz syndrome

Directory of Open Access Journals (Sweden)

Gozde Ozcan

2016-01-01

Full Text Available Gorlin–Goltz syndrome (GGS is an uncommon autosomal dominant inherited disorder which comprises the triad of basal cell carcinomas (BCCs, odontogenic keratocysts, and musculoskeletal malformations. Besides this triad, neurological, ophthalmic, endocrine, and genital manifestations are known to be variable. It is occasionally associated with aggressive BCC and internal malignancies. This report documents a case of GGS with a novel mutation in the PTCH1 gene in an 11-year-old child. The clinical, radiographic, histopathologic and molecular findings of this condition, and treatment are described, and a review of GGS was carried out.
Transcription of human resistin gene involves an interaction of Sp1 with peroxisome proliferator-activating receptor gamma (PPARgamma.

Directory of Open Access Journals (Sweden)

Anil K Singh

2010-03-01

Full Text Available Resistin is a cysteine rich protein, mainly expressed and secreted by circulating human mononuclear cells. While several factors responsible for transcription of mouse resistin gene have been identified, not much is known about the factors responsible for the differential expression of human resistin.We show that the minimal promoter of human resistin lies within approximately 80 bp sequence upstream of the transcriptional start site (-240 whereas binding sites for cRel, CCAAT enhancer binding protein alpha (C/EBP-alpha, activating transcription factor 2 (ATF-2 and activator protein 1 (AP-1 transcription factors, important for induced expression, are present within sequences up to -619. Specificity Protein 1(Sp1 binding site (-276 to -295 is also present and an interaction of Sp1 with peroxisome proliferator activating receptor gamma (PPARgamma is necessary for constitutive expression in U937 cells. Indeed co-immunoprecipitation assay demonstrated a direct physical interaction of Sp1 with PPARgamma in whole cell extracts of U937 cells. Phorbol myristate acetate (PMA upregulated the expression of resistin mRNA in U937 cells by increasing the recruitment of Sp1, ATF-2 and PPARgamma on the resistin gene promoter. Furthermore, PMA stimulation of U937 cells resulted in the disruption of Sp1 and PPARgamma interaction. Chromatin immunoprecipitation (ChIP assay confirmed the recruitment of transcription factors phospho ATF-2, Sp1, Sp3, PPARgamma, chromatin modifier histone deacetylase 1 (HDAC1 and the acetylated form of histone H3 but not cRel, C/EBP-alpha and phospho c-Jun during resistin gene transcription.Our findings suggest a complex interplay of Sp1 and PPARgamma along with other transcription factors that drives the expression of resistin in human monocytic U937 cells.
Trypanosoma brucei TBRGG1, a mitochondrial oligo(U)-binding protein that co-localizes with an in vitro RNA editing activity

NARCIS (Netherlands)

Vanhamme, L.; Perez-Morga, D.; Marchal, C.; Speijer, D.; Lambert, L.; Geuskens, M.; Alexandre, S.; Ismaïli, N.; Göringer, U.; Benne, R.; Pays, E.

1998-01-01

We report the characterization of a Trypanosoma brucei 75-kDa protein of the RGG (Arg-Gly-Gly) type, termed TBRGG1. Dicistronic and monocistronic transcripts of the TBRGG1 gene were produced by both alternative splicing and polyadenylation. TBRGG1 was found in two or three forms that differ in their
Identification of a novel mutation in the PTCH gene in a patient with Gorlin-Goltz syndrome with unusual ocular disorders.

Science.gov (United States)

Romano, Mary; Iacovello, Daniela; Cascone, Nikhil C; Contestabile, Maria Teresa

2011-01-01

To document the clinical, functional, and in vivo microanatomic characteristics of a patient with Gorlin-Goltz syndrome with a novel nonsense mutation in PTCH (patched). Optical coherence tomography (OCT), fluorescein angiography, electrophysiologic testing, visual field, magnetic resonance imaging, and mutation screening of PTCH gene. Visual acuity was 20/20 in the right eye and 20/25 in the left. Fundus examination revealed myelinated nerve fibers in the left eye and bilateral epiretinal membranes with lamellar macular hole also documented with macular OCT. A reduction of the retinal nerve fiber layers in both eyes was found with fiber nervous OCT. Fluorescein angiography showed bilaterally foveal hyperfluorescence and the visual field revealed inferior hemianopia in the right eye. Pattern visual evoked potentials registered a reduction of amplitude in both eyes and latency was delayed in the left eye. Pattern electroretinogram showed a reduction in P50 and N95 peak time and a delay in P50 peak time in the left eye. Flash electroretinogram was reduced in rod response, maximal response, and oscillatory potentials in both eyes. Cone response was normal and 30-Hz flicker was slightly reduced in both eyes. Mutation screening identified a novel nonsense mutation in PTCH. A novel nonsense mutation in the PTCH gene was found. We report the occurrence of epiretinal membranes and the persistence of myelinated nerve fibers. Electrophysiologic and visual field alterations, supporting a neuroretinal dysfunction, were also documented.

Sall4-Gli3 system in early limb progenitors is essential for the development of limb skeletal elements.

Science.gov (United States)

Akiyama, Ryutaro; Kawakami, Hiroko; Wong, Julia; Oishi, Isao; Nishinakamura, Ryuichi; Kawakami, Yasuhiko

2015-04-21

Limb skeletal elements originate from the limb progenitor cells, which undergo expansion and patterning to develop each skeletal element. Posterior-distal skeletal elements, such as the ulna/fibula and posterior digits develop in a Sonic hedgehog (Shh)-dependent manner. However, it is poorly understood how anterior-proximal elements, such as the humerus/femur, the radius/tibia and the anterior digits, are developed. Here we show that the zinc finger factors Sall4 and Gli3 cooperate for proper development of the anterior-proximal skeletal elements and also function upstream of Shh-dependent posterior skeletal element development. Conditional inactivation of Sall4 in the mesoderm before limb outgrowth caused severe defects in the anterior-proximal skeletal elements in the hindlimb. We found that Gli3 expression is reduced in Sall4 mutant hindlimbs, but not in forelimbs. This reduction caused posteriorization of nascent hindlimb buds, which is correlated with a loss of anterior digits. In proximal development, Sall4 integrates Gli3 and the Plzf-Hox system, in addition to proliferative expansion of cells in the mesenchymal core of nascent hindlimb buds. Whereas forelimbs developed normally in Sall4 mutants, further genetic analysis identified that the Sall4-Gli3 system is a common regulator of the early limb progenitor cells in both forelimbs and hindlimbs. The Sall4-Gli3 system also functions upstream of the Shh-expressing ZPA and the Fgf8-expressing AER in fore- and hindlimbs. Therefore, our study identified a critical role of the Sall4-Gli3 system at the early steps of limb development for proper development of the appendicular skeletal elements.
Eviction of linker histone H1 by NAP-family histone chaperones enhances activated transcription.

Science.gov (United States)

Zhang, Qian; Giebler, Holli A; Isaacson, Marisa K; Nyborg, Jennifer K

2015-01-01

In the Metazoan nucleus, core histones assemble the genomic DNA to form nucleosome arrays, which are further compacted into dense chromatin structures by the linker histone H1. The extraordinary density of chromatin creates an obstacle for accessing the genetic information. Regulation of chromatin dynamics is therefore critical to cellular homeostasis, and histone chaperones serve as prominent players in these processes. In the current study, we examined the role of specific histone chaperones in negotiating the inherently repressive chromatin structure during transcriptional activation. Using a model promoter, we demonstrate that the human nucleosome assembly protein family members hNap1 and SET/Taf1β stimulate transcription in vitro during pre-initiation complex formation, prior to elongation. This stimulatory effect is dependent upon the presence of activators, p300, and Acetyl-CoA. We show that transcription from our chromatin template is strongly repressed by H1, and that both histone chaperones enhance RNA synthesis by overcoming H1-induced repression. Importantly, both hNap1 and SET/Taf1β directly bind H1, and function to enhance transcription by evicting the linker histone from chromatin reconstituted with H1. In vivo studies demonstrate that SET/Taf1β, but not hNap1, strongly stimulates activated transcription from the chromosomally-integrated model promoter, consistent with the observation that SET/Taf1β is nuclear, whereas hNap1 is primarily cytoplasmic. Together, these observations indicate that SET/Taf1β may serve as a critical regulator of H1 dynamics and gene activation in vivo. These studies uncover a novel function for SET that mechanistically couples transcriptional derepression with H1 dynamics. Furthermore, they underscore the significance of chaperone-dependent H1 displacement as an essential early step in the transition of a promoter from a dense chromatin state into one that is permissive to transcription factor binding and robust
Regulation of circadian clock transcriptional output by CLOCK:BMAL1

Science.gov (United States)

Trott, Alexandra J.

2018-01-01

The mammalian circadian clock relies on the transcription factor CLOCK:BMAL1 to coordinate the rhythmic expression of 15% of the transcriptome and control the daily regulation of biological functions. The recent characterization of CLOCK:BMAL1 cistrome revealed that although CLOCK:BMAL1 binds synchronously to all of its target genes, its transcriptional output is highly heterogeneous. By performing a meta-analysis of several independent genome-wide datasets, we found that the binding of other transcription factors at CLOCK:BMAL1 enhancers likely contribute to the heterogeneity of CLOCK:BMAL1 transcriptional output. While CLOCK:BMAL1 rhythmic DNA binding promotes rhythmic nucleosome removal, it is not sufficient to generate transcriptionally active enhancers as assessed by H3K27ac signal, RNA Polymerase II recruitment, and eRNA expression. Instead, the transcriptional activity of CLOCK:BMAL1 enhancers appears to rely on the activity of ubiquitously expressed transcription factors, and not tissue-specific transcription factors, recruited at nearby binding sites. The contribution of other transcription factors is exemplified by how fasting, which effects several transcription factors but not CLOCK:BMAL1, either decreases or increases the amplitude of many rhythmically expressed CLOCK:BMAL1 target genes. Together, our analysis suggests that CLOCK:BMAL1 promotes a transcriptionally permissive chromatin landscape that primes its target genes for transcription activation rather than directly activating transcription, and provides a new framework to explain how environmental or pathological conditions can reprogram the rhythmic expression of clock-controlled genes. PMID:29300726
The single nucleotide polymorphism Gly482Ser in the PGC-1α gene impairs exercise-induced slow-twitch muscle fibre transformation in humans.

Directory of Open Access Journals (Sweden)

Peter Steinbacher

Full Text Available PGC-1α (peroxisome proliferator-activated receptor γ co-activator 1α is an important regulator of mitochondrial biogenesis and a master regulator of enzymes involved in oxidative phosphorylation. Recent evidence demonstrated that the Gly482Ser single nucleotide polymorphism (SNP in the PGC-1α gene affects insulin sensitivity, blood lipid metabolism and binding to myocyte enhancer factor 2 (MEF2. Individuals carrying this SNP were shown to have a reduced cardiorespiratory fitness and a higher risk to develop type 2 diabetes. Here, we investigated the responses of untrained men with the Gly482Ser SNP to a 10 week programme of endurance training (cycling, 3 x 60 min/week, heart rate at 70-90% VO2peak. Quantitative data from analysis of biopsies from vastus lateralis muscle revealed that the SNP group, in contrast to the control group, lacked a training-induced increase in content of slow contracting oxidative fibres. Capillary supply, mitochondrial density, mitochondrial enzyme activities and intramyocellular lipid content increased similarly in both groups. These results indicate that the impaired binding of MEF2 to PGC-1α in humans with this SNP impedes exercise-induced fast-to-slow muscle fibre transformation.
The single nucleotide polymorphism Gly482Ser in the PGC-1α gene impairs exercise-induced slow-twitch muscle fibre transformation in humans.

Science.gov (United States)

Steinbacher, Peter; Feichtinger, René G; Kedenko, Lyudmyla; Kedenko, Igor; Reinhardt, Sandra; Schönauer, Anna-Lena; Leitner, Isabella; Sänger, Alexandra M; Stoiber, Walter; Kofler, Barbara; Förster, Holger; Paulweber, Bernhard; Ring-Dimitriou, Susanne

2015-01-01

PGC-1α (peroxisome proliferator-activated receptor γ co-activator 1α) is an important regulator of mitochondrial biogenesis and a master regulator of enzymes involved in oxidative phosphorylation. Recent evidence demonstrated that the Gly482Ser single nucleotide polymorphism (SNP) in the PGC-1α gene affects insulin sensitivity, blood lipid metabolism and binding to myocyte enhancer factor 2 (MEF2). Individuals carrying this SNP were shown to have a reduced cardiorespiratory fitness and a higher risk to develop type 2 diabetes. Here, we investigated the responses of untrained men with the Gly482Ser SNP to a 10 week programme of endurance training (cycling, 3 x 60 min/week, heart rate at 70-90% VO2peak). Quantitative data from analysis of biopsies from vastus lateralis muscle revealed that the SNP group, in contrast to the control group, lacked a training-induced increase in content of slow contracting oxidative fibres. Capillary supply, mitochondrial density, mitochondrial enzyme activities and intramyocellular lipid content increased similarly in both groups. These results indicate that the impaired binding of MEF2 to PGC-1α in humans with this SNP impedes exercise-induced fast-to-slow muscle fibre transformation.
The novel RAF1 mutation p.(Gly361Ala) located outside the kinase domain of the CR3 region in two patients with Noonan syndrome, including one with a rare brain tumor.

Science.gov (United States)

Harms, Frederike L; Alawi, Malik; Amor, David J; Tan, Tiong Y; Cuturilo, Goran; Lissewski, Christina; Brinkmann, Julia; Schanze, Denny; Kutsche, Kerstin; Zenker, Martin

2018-02-01

Noonan syndrome is characterized by typical craniofacial dysmorphism, postnatal growth retardation, congenital heart defect, and learning difficulties and belongs to the RASopathies, a group of neurodevelopmental disorders caused by germline mutations in genes encoding components of the RAS-MAPK pathway. Mutations in the RAF1 gene are associated with Noonan syndrome, with a high prevalence of hypertrophic cardiomyopathy (HCM). RAF1 mutations cluster in exons encoding the conserved region 2 (CR2), the kinase activation segment of the CR3 domain, and the C-terminus. We present two boys with Noonan syndrome and the identical de novo RAF1 missense variant c.1082G>C/p.(Gly361Ala) affecting the CR3, but located outside the kinase activation segment. The p.(Gly361Ala) mutation has been identified as a RAF1 allele conferring resistance to RAF inhibitors. This amino acid change favors a RAF1 conformation that allows for enhanced RAF dimerization and increased intrinsic kinase activity. Both patients with Noonan syndrome showed typical craniofacial dysmorphism, macrocephaly, and short stature. One individual developed HCM and was diagnosed with a disseminated oligodendroglial-like leptomeningeal tumor (DOLT) of childhood at the age of 9 years. While there is a well-established association of NS with malignant tumors, especially childhood hemato-oncological diseases, brain tumors have rarely been reported in Noonan syndrome. Our data demonstrate that mutation scanning of the entire coding region of genes associated with Noonan syndrome is mandatory not to miss rare variants located outside the known mutational hotspots. © 2017 Wiley Periodicals, Inc.
Arg16Gly and Gln27Glu β2 adrenergic polymorphisms influence cardiac autonomic modulation and baroreflex sensitivity in healthy young Brazilians

Science.gov (United States)

Atala, Magda M; Goulart, Alessandra; Guerra, Grazia M; Mostarda, Cristiano; Rodrigues, Bruno; Mello, Priscila R; Casarine, Dulce E; Irigoyen, Maria-Claudia; Pereira, Alexandre C; Consolim-Colombo, Fernanda M

2015-01-01

The association between functional β2 adrenergic receptor (β2-AR) polymorphisms and cardiac autonomic modulation is still unclear. Thus, two common polymorphisms in the β2-AR gene (Gln27Glu β2 and Arg16Gly β2) were studied to determine whether they might affect tonic and reflex cardiac sympathetic activity in healthy young subjects. A total of 213 healthy young white subjects of both genders (53% female), aged 18-30 years (23.5±3.4 y), had their continuous blood pressure curves noninvasively recorded by Finometer at baseline, and other hemodynamic parameters, as cardiac autonomic modulation, baroreflex sensitivity, and allele, genotype, and diplotype frequencies calculated. Associations were made between Arg16Gly β2 and Gln27Glu β2 polymorphisms and between β2-AR diplotypes and all variables. The heart rate was significantly lower (P<0.001) in the presence of homozygous Arg/Arg alleles (60.9±1.5 bpm) than in that of Arg/Gly heterozygotes (65.9±1.0 bpm) or Gly/Gly homozygotes (66.3±1.2 bpm). Homozygous carriers of Arg16 allele had an alpha index (19.2±1.3) significantly higher (P<0.001) than that of the subjects with the Gly allele Gly/Gly (14.5±0.7) or Arg/Gly (14.6±0.7). Furthermore, the recessive Glu27Glu and the heterozygous Gln27Glu genotypes had a higher percentage of low-frequency components (LF%) than the homozygous Gln27Gln (15.1% vs. 16.0% vs. 8.2%, P=0.03, respectively). In healthy young subjects, the presence of β2-AR Arg16 allele in a recessive model was associated with higher baroreflex sensitivity, and increased parasympathetic modulation in studied individuals. PMID:25755837
Depigmenting Effect of Resveratrol Is Dependent on FOXO3a Activation without SIRT1 Activation.

Science.gov (United States)

Kwon, Soon-Hyo; Choi, Hye-Ryung; Kang, Youn-A; Park, Kyoung-Chan

2017-06-07

Resveratrol exhibits not only anti-melanogenic property by inhibiting microphthalmia-associated transcription factor (MITF), but also anti-aging property by activating sirtuin-1 (SIRT1). In this study, the relationship between depigmenting effect of resveratrol and SIRT1/forkhead box O (FOXO) 3a activation and was investigated. Resveratrol suppressed melanogenesis by the downregulation of MITF and tyrosinase via ERK pathway. Results showed that the expression of both SIRT1 and FOXO3a were increased. It is reported that SIRT1 is critical regulator of FOXO-mediated transcription in response to oxidative stress. However in our study, FOXO3a activation appeared earlier than that of SIRT1. Furthermore, the effect of resveratrol on the levels of MITF and tyrosinase was suppressed when melanocytes were pre-treated with SP600125 (JNK inhibitor). However, pre-treatment with SIRT1 inhibitor (EX527, or sirtinol) did not affect the levels of MITF and tyrosinase. Therefore, resveratrol inhibits melanogenesis through the activation of FOXO3a but not by the activation of SIRT1. Although SIRT1 activation by resveratrol is a well-known mechanism of resveratrol-induced antiaging effects, our study showed that not SIRT1 but FOXO3a activation is involved in depigmenting effects of resveratrol.
Covalent attachment of cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) to poly(etheretherketone) surface by tailored silanization layers technique

International Nuclear Information System (INIS)

Zheng, Yanyan; Xiong, Chengdong; Li, Xiaoyu; Zhang, Lifang

2014-01-01

Highlights: • The carbonyl groups on PEEK surface were effectively reduced to hydroxyl groups using sodium borohydride. • Silanization layers technique was employed to immobilize the cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) on hydroxylation-pretreated PEEK sheet surface by covalent chemical attachment. • XPS, surface profiler and water contact angle measurements proved the presence of GRGD on PEEK surface. • Osteoblast-like cells (MC3T3-E1) attachment and proliferation were improved effectively on GRGD-modified PEEK surface. - Abstract: Poly(etheretherketone) (PEEK) is a rigid semicrystalline polymer that combines excellent mechanical properties, broad chemical resistance and bone-like stiffness and is widely used in biomedical fields. However, PEEK is naturally bioinert, leading to limited biomedical applications, especially when a direct bone-implant osteointegration is desired. In this study, a three-step reaction procedure was employed to immobilize the cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) on the surface of PEEK sheet by covalent chemical attachment to favor cell adhesion and proliferation. First, hydroxylation-pretreated PEEK surfaces were silanized with 7-Oct-1-enyltrichlorosilane (OETS) in dry cyclohexane, resulting in a silanization layer with terminal ethenyl. Second, the terminal ethylenic double bonds of the silanization layer on PEEK surface were converted to carboxyl groups through acidic potassium manganate oxidation. Finally, GRGD was covalently attached by carbodiimide mediated condensation between the carboxyl on PEEK surface and amine presents in GRGD. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, surface profiler and water contact angle measurements were applied to characterize the modified surfaces. The effect of cells attachment and proliferation on each specimen was investigated. Pre-osteoblast cells (MC3T3-E1) attachment, spreading and proliferation
Covalent attachment of cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) to poly(etheretherketone) surface by tailored silanization layers technique

Energy Technology Data Exchange (ETDEWEB)

Zheng, Yanyan [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xiong, Chengdong [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China); Li, Xiaoyu [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Zhang, Lifang, E-mail: zhanglfcioc@163.com [Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041 (China)

2014-11-30

Highlights: • The carbonyl groups on PEEK surface were effectively reduced to hydroxyl groups using sodium borohydride. • Silanization layers technique was employed to immobilize the cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) on hydroxylation-pretreated PEEK sheet surface by covalent chemical attachment. • XPS, surface profiler and water contact angle measurements proved the presence of GRGD on PEEK surface. • Osteoblast-like cells (MC3T3-E1) attachment and proliferation were improved effectively on GRGD-modified PEEK surface. - Abstract: Poly(etheretherketone) (PEEK) is a rigid semicrystalline polymer that combines excellent mechanical properties, broad chemical resistance and bone-like stiffness and is widely used in biomedical fields. However, PEEK is naturally bioinert, leading to limited biomedical applications, especially when a direct bone-implant osteointegration is desired. In this study, a three-step reaction procedure was employed to immobilize the cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) on the surface of PEEK sheet by covalent chemical attachment to favor cell adhesion and proliferation. First, hydroxylation-pretreated PEEK surfaces were silanized with 7-Oct-1-enyltrichlorosilane (OETS) in dry cyclohexane, resulting in a silanization layer with terminal ethenyl. Second, the terminal ethylenic double bonds of the silanization layer on PEEK surface were converted to carboxyl groups through acidic potassium manganate oxidation. Finally, GRGD was covalently attached by carbodiimide mediated condensation between the carboxyl on PEEK surface and amine presents in GRGD. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, surface profiler and water contact angle measurements were applied to characterize the modified surfaces. The effect of cells attachment and proliferation on each specimen was investigated. Pre-osteoblast cells (MC3T3-E1) attachment, spreading and proliferation
Regulation of Neph3 gene in podocytes - key roles of transcription factors NF-kappaB and Sp1

LENUS (Irish Health Repository)

Ristola, Mervi

2009-08-24

Abstract Background Neph3 (filtrin) is expressed in the glomerular podocytes where it localizes at the specialized cell adhesion structures of the foot processes called slit diaphragms which form the outermost layer of the glomerular filtration barrier. Neph3 protein shows homology and structural similarity to Neph1, Neph2 and nephrin, which all are crucial for maintaining the normal glomerular ultrafiltration function. The exact function of Neph3 in the kidney is not known but we have previously shown that the level of Neph3 mRNA is decreased in proteinuric diseases. This suggests that Neph3 may play a role in the pathogenesis of kidney damage, and emphasizes the need to analyze the regulatory mechanisms of Neph3 gene. In this study we investigated the transcriptional regulation of Neph3 gene by identifying transcription factors that control Neph3 expression. Results We cloned and characterized approximately 5 kb fragment upstream of the Neph3 gene. Neph3 proximal promoter near the transcription start site was found to be devoid of TATA and CAAT boxes, but to contain a highly GC-rich area. Using promoter reporter gene constructs, we localized the main activating regulatory region of Neph3 gene in its proximal promoter region from -105 to -57. Within this region, putative transcription factor binding sites for NF-κB and Sp1 were found by computational analysis. Mutational screening indicated that NF-κB and Sp1 response elements are essential for the basal transcriptional activity of the Neph3 promoter. Co-transfection studies further showed that NF-κB and Sp1 regulate Neph3 promoter activity. In addition, overexpression of NF-κB increased endogenous Neph3 gene expression. Chromatin immunoprecipitation assay using cultured human podocytes demonstrated that both NF-κB and Sp1 interact with the Neph3 promoter. Conclusion Our results show that NF-κB and Sp1 are key regulators of Neph3 expression at the basal level in podocytes, therefore providing new insight
Intestinal drug transport via the proton-coupled amino acid transporter PAT1 (SLC36A1) is inhibited by Gly-X(aa) dipeptides

DEFF Research Database (Denmark)

Frølund, Sidsel; Langthaler, Louise; Kall, Morten A

2012-01-01

-Sar as substrates of the amino acid transporter PAT1. The aim of the present study is to investigate if other Gly-containing dipeptides interact with PAT1, and whether they can inhibit PAT1 mediated drug absorption, in vitro and in vivo. The in vitro methods included two-electrode voltage clamp measurements on h...... of different dipeptides. The in vivo part consisted of a pharmacokinetic study in rats following oral administration of gaboxadol and preadministration of 200 mg/kg dipeptide. The results showed that in hPAT1 expressing oocytes Gly-Tyr, Gly-Pro, and Gly-Phe inhibited currents induced by drug substances......, the present study identifies selected dipeptides as inhibitors of PAT1 mediated drug absorption in various in vitro models....
Secondary Structure Adopted by the Gly-Gly-X Repetitive Regions of Dragline Spider Silk

Directory of Open Access Journals (Sweden)

Geoffrey M. Gray

2016-12-01

Full Text Available Solid-state NMR and molecular dynamics (MD simulations are presented to help elucidate the molecular secondary structure of poly(Gly-Gly-X, which is one of the most common structural repetitive motifs found in orb-weaving dragline spider silk proteins. The combination of NMR and computational experiments provides insight into the molecular secondary structure of poly(Gly-Gly-X segments and provides further support that these regions are disordered and primarily non-β-sheet. Furthermore, the combination of NMR and MD simulations illustrate the possibility for several secondary structural elements in the poly(Gly-Gly-X regions of dragline silks, including β-turns, 310-helicies, and coil structures with a negligible population of α-helix observed.
The ciliogenic transcription factor RFX3 regulates early midline distribution of guidepost neurons required for corpus callosum development.

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Carine Benadiba

Full Text Available The corpus callosum (CC is the major commissure that bridges the cerebral hemispheres. Agenesis of the CC is associated with human ciliopathies, but the origin of this default is unclear. Regulatory Factor X3 (RFX3 is a transcription factor involved in the control of ciliogenesis, and Rfx3-deficient mice show several hallmarks of ciliopathies including left-right asymmetry defects and hydrocephalus. Here we show that Rfx3-deficient mice suffer from CC agenesis associated with a marked disorganisation of guidepost neurons required for axon pathfinding across the midline. Using transplantation assays, we demonstrate that abnormalities of the mutant midline region are primarily responsible for the CC malformation. Conditional genetic inactivation shows that RFX3 is not required in guidepost cells for proper CC formation, but is required before E12.5 for proper patterning of the cortical septal boundary and hence accurate distribution of guidepost neurons at later stages. We observe focused but consistent ectopic expression of Fibroblast growth factor 8 (Fgf8 at the rostro commissural plate associated with a reduced ratio of GLIoma-associated oncogene family zinc finger 3 (GLI3 repressor to activator forms. We demonstrate on brain explant cultures that ectopic FGF8 reproduces the guidepost neuronal defects observed in Rfx3 mutants. This study unravels a crucial role of RFX3 during early brain development by indirectly regulating GLI3 activity, which leads to FGF8 upregulation and ultimately to disturbed distribution of guidepost neurons required for CC morphogenesis. Hence, the RFX3 mutant mouse model brings novel understandings of the mechanisms that underlie CC agenesis in ciliopathies.
Dietary agent, benzyl isothiocyanate inhibits signal transducer and activator of transcription 3 phosphorylation and collaborates with sulforaphane in the growth suppression of PANC-1 cancer cells

Directory of Open Access Journals (Sweden)

Deangelis Stephanie

2009-08-01

Full Text Available Abstract The Signal Transducer and Activator of Transcription (STAT proteins comprise a family of latent transcription factors with diverse functions. STAT3 has well established roles in cell proliferation, growth and survival, and its persistent activation has been detected with high frequency in many human cancers. As constitutive activation of STAT3 appears to be vital for the continued survival of these cancerous cells, it has emerged as an attractive target for chemotherapeutics. We examined whether the inhibitory activities of bioactive compounds from cruciferous vegetables, such as Benzyl isothiocyanate (BITC and sulforaphane, extended to STAT3 activation in PANC-1 human pancreatic cancer cells. BITC and sulforaphane were both capable of inhibiting cell viability and inducing apoptosis in PANC-1. Sulforaphane had minimal effect on the direct inhibition of STAT3 tyrosine phosphorylation, however, suggesting its inhibitory activities are most likely STAT3-independent. Conversely, BITC was shown to inhibit the tyrosine phosphorylation of STAT3, but not the phosphorylation of ERK1/2, MAPK and p70S6 kinase. These results suggest that STAT3 may be one of the targets of BITC-mediated inhibition of cell viability in PANC-1 cancer cells. In addition, we show that BITC can prevent the induction of STAT3 activation by Interleukin-6 in MDA-MB-453 breast cancer cells. Furthermore, combinations of BITC and sulforaphane inhibited cell viability and STAT3 phosphorylation more dramatically than either agent alone. These findings suggest that the combination of the dietary agents BITC and sulforaphane has potent inhibitory activity in pancreatic cancer cells and that they may have translational potential as chemopreventative or therapeutic agents.
Abscisic acid affects transcription of chloroplast genes via protein phosphatase 2C-dependent activation of nuclear genes: repression by guanosine-3'-5'-bisdiphosphate and activation by sigma factor 5.

Science.gov (United States)

Yamburenko, Maria V; Zubo, Yan O; Börner, Thomas

2015-06-01

Abscisic acid (ABA) represses the transcriptional activity of chloroplast genes (determined by run-on assays), with the exception of psbD and a few other genes in wild-type Arabidopsis seedlings and mature rosette leaves. Abscisic acid does not influence chloroplast transcription in the mutant lines abi1-1 and abi2-1 with constitutive protein phosphatase 2C (PP2C) activity, suggesting that ABA affects chloroplast gene activity by binding to the pyrabactin resistance (PYR)/PYR1-like or regulatory component of ABA receptor protein family (PYR/PYL/RCAR) and signaling via PP2Cs and sucrose non-fermenting protein-related kinases 2 (SnRK2s). Further we show by quantitative PCR that ABA enhances the transcript levels of RSH2, RSH3, PTF1 and SIG5. RelA/SpoT homolog 2 (RSH2) and RSH3 are known to synthesize guanosine-3'-5'-bisdiphosphate (ppGpp), an inhibitor of the plastid-gene-encoded chloroplast RNA polymerase. We propose, therefore, that ABA leads to an inhibition of chloroplast gene expression via stimulation of ppGpp synthesis. On the other hand, sigma factor 5 (SIG5) and plastid transcription factor 1 (PTF1) are known to be necessary for the transcription of psbD from a specific light- and stress-induced promoter (the blue light responsive promoter, BLRP). We demonstrate that ABA activates the psbD gene by stimulation of transcription initiation at BLRP. Taken together, our data suggest that ABA affects the transcription of chloroplast genes by a PP2C-dependent activation of nuclear genes encoding proteins involved in chloroplast transcription. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.
Synergistic cooperation of MDM2 and E2F1 contributes to TAp73 transcriptional activity

Energy Technology Data Exchange (ETDEWEB)

Kasim, Vivi, E-mail: vivikasim78@gmail.com [The Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Huang, Can; Zhang, Jing; Jia, Huizhen; Wang, Yunxia [The Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Yang, Li [The Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); The 111 Project Laboratory of Biomechanics and Tissue Repair, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Miyagishi, Makoto [Molecular Composite Medicine Research Group, Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8566 (Japan); Wu, Shourong, E-mail: shourongwu@hotmail.com [The Key Laboratory of Biorheological Science and Technology, Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); The 111 Project Laboratory of Biomechanics and Tissue Repair, College of Bioengineering, Chongqing University, Chongqing 400044 (China)

2014-07-04

Highlights: • MDM2 is a novel positive regulator of TAp73 transcriptional activity. • MDM2 colocalizes together and physically interacts with E2F1. • Synergistic cooperation of MDM2 and E2F1 is crucial for TAp73 transcription. • MDM2 regulates TAp73 transcriptional activity in a p53-independent manner. - Abstract: TAp73, a structural homologue of p53, plays an important role in tumorigenesis. E2F1 had been reported as a transcriptional regulator of TAp73, however, the detailed mechanism remains to be elucidated. Here we reported that MDM2-silencing reduced the activities of the TAp73 promoters and the endogenous TAp73 expression level significantly; while MDM2 overexpression upregulated them. We further revealed that the regulation of TAp73 transcriptional activity occurs as a synergistic effect of MDM2 and E2F1, most probably through their physical interaction in the nuclei. Furthermore, we also suggested that MDM2 might be involved in DNA damage-induced TAp73 transcriptional activity. Finally, we elucidated that MDM2-silencing reduced the proliferation rate of colon carcinoma cells regardless of the p53 status. Our data show a synergistic effect of MDM2 and E2F1 on TAp73 transcriptional activity, suggesting a novel regulation pathway of TAp73.
Synergistic cooperation of MDM2 and E2F1 contributes to TAp73 transcriptional activity

International Nuclear Information System (INIS)

Kasim, Vivi; Huang, Can; Zhang, Jing; Jia, Huizhen; Wang, Yunxia; Yang, Li; Miyagishi, Makoto; Wu, Shourong

2014-01-01

Highlights: • MDM2 is a novel positive regulator of TAp73 transcriptional activity. • MDM2 colocalizes together and physically interacts with E2F1. • Synergistic cooperation of MDM2 and E2F1 is crucial for TAp73 transcription. • MDM2 regulates TAp73 transcriptional activity in a p53-independent manner. - Abstract: TAp73, a structural homologue of p53, plays an important role in tumorigenesis. E2F1 had been reported as a transcriptional regulator of TAp73, however, the detailed mechanism remains to be elucidated. Here we reported that MDM2-silencing reduced the activities of the TAp73 promoters and the endogenous TAp73 expression level significantly; while MDM2 overexpression upregulated them. We further revealed that the regulation of TAp73 transcriptional activity occurs as a synergistic effect of MDM2 and E2F1, most probably through their physical interaction in the nuclei. Furthermore, we also suggested that MDM2 might be involved in DNA damage-induced TAp73 transcriptional activity. Finally, we elucidated that MDM2-silencing reduced the proliferation rate of colon carcinoma cells regardless of the p53 status. Our data show a synergistic effect of MDM2 and E2F1 on TAp73 transcriptional activity, suggesting a novel regulation pathway of TAp73
ETS transcription factors control transcription of EZH2 and epigenetic silencing of the tumor suppressor gene Nkx3.1 in prostate cancer.

Directory of Open Access Journals (Sweden)

Paolo Kunderfranco

2010-05-01

Full Text Available ETS transcription factors regulate important signaling pathways involved in cell differentiation and development in many tissues and have emerged as important players in prostate cancer. However, the biological impact of ETS factors in prostate tumorigenesis is still debated.We performed an analysis of the ETS gene family using microarray data and real-time PCR in normal and tumor tissues along with functional studies in normal and cancer cell lines to understand the impact in prostate tumorigenesis and identify key targets of these transcription factors. We found frequent dysregulation of ETS genes with oncogenic (i.e., ERG and ESE1 and tumor suppressor (i.e., ESE3 properties in prostate tumors compared to normal prostate. Tumor subgroups (i.e., ERG(high, ESE1(high, ESE3(low and NoETS tumors were identified on the basis of their ETS expression status and showed distinct transcriptional and biological features. ERG(high and ESE3(low tumors had the most robust gene signatures with both distinct and overlapping features. Integrating genomic data with functional studies in multiple cell lines, we demonstrated that ERG and ESE3 controlled in opposite direction transcription of the Polycomb Group protein EZH2, a key gene in development, differentiation, stem cell biology and tumorigenesis. We further demonstrated that the prostate-specific tumor suppressor gene Nkx3.1 was controlled by ERG and ESE3 both directly and through induction of EZH2.These findings provide new insights into the role of the ETS transcriptional network in prostate tumorigenesis and uncover previously unrecognized links between aberrant expression of ETS factors, deregulation of epigenetic effectors and silencing of tumor suppressor genes. The link between aberrant ETS activity and epigenetic gene silencing may be relevant for the clinical management of prostate cancer and design of new therapeutic strategies.
An activator of transcription regulates phage TP901-1 late gene expression

DEFF Research Database (Denmark)

Brøndsted, Lone; Pedersen, Margit; Hammer, Karin

2001-01-01

bp contains both the promoter and the region necessary for activation by ORF29. The transcriptional start site of the promoter was identified by primer extension to position 13073 on the TP901-1 genome, thus located 87 bp downstream of orf29 in a 580-bp intergenic region between orf29 and orf30....... Furthermore, the region located -85 to -61 bp upstream of the start site was shown to be necessary for promoter activity. During infection, the transcript arising from the late promoter is fully induced at 40 min postinfection, and our results suggest that a certain level of ORF29 must he reached in order...... to activate transcription of the promoter. Several lactococcal bacteriophages encode ORF29 homologous proteins, indicating that late transcription may be controlled by a similar mechanism in these phages. With the identification of this novel regulator, our results suggest that within the P335 group...

A critique on nuclear factor-kappa B and signal transducer and activator of transcription 3: The key transcription factors in periodontal pathogenesis

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Ranjith Ambili

2017-01-01

Full Text Available Periodontal disease is initiated by microorganisms in dental plaque, and host immunoinflammatory response to the microbial challenge helps in disease progression. Conventional periodontal therapy was mainly targeted on the elimination of microbial component. However, a better understanding of molecular aspects in host response will enable the clinicians to formulate effective host modulation therapy (HMT for the periodontal management. Inflammatory mediators were the main targets for HMT in the past. Transcription factors can regulate the production of multiple mediators simultaneously, and inhibition of these factors will be more beneficial than blocking individual molecule. Two important transcription factors implicated in chronic inflammatory diseases are nuclear factor kappa B (NF-κB and signal transducers and activators of transcription 3. The role of these factors in periodontal disease is a less explored area. This comprehensive review is aimed at unveiling the critical role of NF-κB and signal transducers and activators of transcription 3 in periodontal pathogenesis. An online search was performed using MEDLINE/PubMed database. All publications till 2016 related to NF-κB, signal transducer and activator of transcription 3 (STAT3, and inflammation were included in writing this review. A total of 27,390 references were published based on the search terms used. Out of these, 507 were related to the periodontal research published in English till 2016. Relevant papers were chosen after carefully reading the abstract. This review has attempted to comprehend the existing knowledge regarding the role of transcription factors NF-κB and STAT3 in periodontal disease. Moreover, it also provides a connecting molecular link for the periodontal medicine concept.
Radiation Chemical Studies of Gly-Met-Gly in Aqueous Solution

NARCIS (Netherlands)

Barata-Vallejo, Sebastian; Ferreri, Carla; Zhang, Tao; Permentier, Hjalmar; Bischoff, Rainer; Bobrowski, Krzysztof; Chatgilialoglu, Chryssostomos

2016-01-01

Important biological consequences are related to the reaction of HO(•) radicals with methionine (Met). Several fundamental aspects remain to be defined when Met is an amino acid residue incorporated in the interior of peptides and proteins. The present study focuses on Gly-Met-Gly, the simplest
APOBEC3G inhibits HIV-1 RNA elongation by inactivating the viral trans-activation response element.

Science.gov (United States)

Nowarski, Roni; Prabhu, Ponnandy; Kenig, Edan; Smith, Yoav; Britan-Rosich, Elena; Kotler, Moshe

2014-07-29

Deamination of cytidine residues in viral DNA is a major mechanism by which APOBEC3G (A3G) inhibits vif-deficient human immunodeficiency virus type 1 (HIV-1) replication. dC-to-dU transition following RNase-H activity leads to viral cDNA degradation, production of non-functional proteins, formation of undesired stop codons and decreased viral protein synthesis. Here, we demonstrate that A3G provides an additional layer of defense against HIV-1 infection dependent on inhibition of proviral transcription. HIV-1 transcription elongation is regulated by the trans-activation response (TAR) element, a short stem-loop RNA structure required for elongation factors binding. Vif-deficient HIV-1-infected cells accumulate short viral transcripts and produce lower amounts of full-length HIV-1 transcripts due to A3G deamination of the TAR apical loop cytidine, highlighting the requirement for TAR loop integrity in HIV-1 transcription. We further show that free single-stranded DNA (ssDNA) termini are not essential for A3G activity and a gap of CCC motif blocked with juxtaposed DNA or RNA on either or 3'+5' ends is sufficient for A3G deamination. These results identify A3G as an efficient mutator and that deamination of (-)SSDNA results in an early block of HIV-1 transcription. Copyright © 2014 Elsevier Ltd. All rights reserved.
Dexamethasone (DEX induces Osmotic stress transcription factor 1 (Ostf1 through the Akt-GSK3β pathway in freshwater Japanese eel gill cell cultures

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S. C. Chow

2013-03-01

Osmosensing and osmoregulatory processes undertaken in gills of euryhaline fish are coordinated by integrative actions of various signaling molecules/transcriptional factors. Considerable numbers of studies report the hyper- and hypo-osmoregulatory functions of fish gills, by illustrating the process of gill cell remodeling and the modulation of the expression of ion channels/transporters. Comparatively mechanistic information relayed from signal integration to transcriptional regulation in mediating gill cell functions has not yet been elucidated. In this study we demonstrate the functional links from cortisol stimulation, to Akt activation, to the expression of the transcriptional factor, Ostf1. Using the synthetic glucocorticoid receptor agonist, dexamethasone (DEX, Ostf1 expression is found to be activated via glucocorticoid receptor (GR and mediated by the Akt-GSK3β signaling pathway. Pharmacological experiments using kinase inhibitors reveal that the expression of Ostf1 is negatively regulated by Akt activation. The inhibition of PI3K or Akt activities, by the specific kinase inhibitors (wortmannin, LY294002 or SH6, stimulates Ostf1 expression, while a reduction of GSK3β activity by LiCl reduces Ostf1 expression. Collectively, our report for the first time indicates that DEX can induce Ostf1 via GR, with the involvement of the Akt-GSK3β signaling pathway in primary eel gill cell cultures. The data also suggest that Ostf1 may play different roles in gill cell survival during seawater acclimation.
Abscisic acid-dependent multisite phosphorylation regulates the activity of a transcription activator AREB1

OpenAIRE

Furihata, Takashi; Maruyama, Kyonoshin; Fujita, Yasunari; Umezawa, Taishi; Yoshida, Riichiro; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2006-01-01

bZIP-type transcription factors AREBs/ABFs bind an abscisic acid (ABA)-responsive cis-acting element named ABRE and transactivate downstream gene expression in Arabidopsis. Because AREB1 overexpression could not induce downstream gene expression, activation of AREB1 requires ABA-dependent posttranscriptional modification. We confirmed that ABA activated 42-kDa kinase activity, which, in turn, phosphorylated Ser/Thr residues of R-X-X-S/T sites in the conserved regions of AREB1. Amino acid subs...
Effective Biotransformation of Ethyl 4-Chloro-3-Oxobutanoate into Ethyl (S)-4-Chloro-3-Hydroxybutanoate by Recombinant E. coli CCZU-T15 Whole Cells in [ChCl][Gly]-Water Media.

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Dai, Yong; Huan, Bin; Zhang, Hai-Sheng; He, Yu-Cai

2017-04-01

To increase the biocatalytic activity of Escherichia coli CCZU-T15 whole cells, choline chloride/glycerol ([ChCl][Gly]) was firstly used as biocompatible solvent for the effective biotransformation of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl (S)-4-chloro-3-hydroxybutanoate [(S)-CHBE]. Furthermore, L-glutamine (150 mM) was added into [ChCl][Gly]-water ([ChCl][Gly] 12.5 vol%, pH 6.5) media instead of NAD + for increasing the biocatalytic efficiency. To further improve the biosynthesis of (S)-CHBE (>99 % e.e.) by E. coli CCZU-T15 whole cells, Tween-80 (7.5 mM) was also added into this reaction media, and (S)-CHBE (>9 % e.e.) could be effectively synthesized from 2000 and 3000 mM COBE in the yields of 100 and 93.0 % by whole cells of recombinant E. coli CCZU-T15, respectively. TEM image indicated that the cell membrane was permeabilized and lost its integrity and when the cell was exposed to [ChCl][Gly]-water media with Tween-80. Clearly, this bioprocess has high potential for the effective biosynthesis of (S)-CHBE (>99 % e.e.).
APOBEC3G inhibits elongation of HIV-1 reverse transcripts.

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Kate N Bishop

2008-12-01

Full Text Available APOBEC3G (A3G is a host cytidine deaminase that, in the absence of Vif, restricts HIV-1 replication and reduces the amount of viral DNA that accumulates in cells. Initial studies determined that A3G induces extensive mutation of nascent HIV-1 cDNA during reverse transcription. It has been proposed that this triggers the degradation of the viral DNA, but there is now mounting evidence that this mechanism may not be correct. Here, we use a natural endogenous reverse transcriptase assay to show that, in cell-free virus particles, A3G is able to inhibit HIV-1 cDNA accumulation not only in the absence of hypermutation but also without the apparent need for any target cell factors. We find that although reverse transcription initiates in the presence of A3G, elongation of the cDNA product is impeded. These data support the model that A3G reduces HIV-1 cDNA levels by inhibiting synthesis rather than by inducing degradation.
The adenovirus oncoprotein E1a stimulates binding of transcription factor ETF to transcriptionally activate the p53 gene.

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Hale, T K; Braithwaite, A W

1999-08-20

Expression of the tumor suppressor protein p53 plays an important role in regulating the cellular response to DNA damage. During adenovirus infection, levels of p53 protein also increase. It has been shown that this increase is due not only to increased stability of the p53 protein but to the transcriptional activation of the p53 gene during infection. We demonstrate here that the E1a proteins of adenovirus are responsible for activating the mouse p53 gene and that both major E1a proteins, 243R and 289R, are required for complete activation. E1a brings about the binding of two cellular transcription factors to the mouse p53 promoter. One of these, ETF, binds to three upstream sites in the p53 promoter and one downstream site, whereas E2F binds to one upstream site in the presence of E1a. Our studies indicate that E2F binding is not essential for activation of the p53 promoter but that ETF is. Our data indicate the ETF site located downstream of the start site of transcription is the key site in conferring E1a responsiveness on the p53 promoter.
A Gly482Ser missense mutation in the peroxisome proliferator-activated receptor gamma coactivator-1 is associated with altered lipid oxidation and early insulin secretion in Pima Indians

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Muller, Yunhua Li; Bogardus, Clifton; Pedersen, Oluf

2003-01-01

of the PGC-1 gene predicts a glycine to serine substitution at amino acid 482 and has been associated with type 2 diabetes in a Danish population. In this study, we examined whether this Gly482Ser polymorphism is associated with type 2 diabetes or obesity, or metabolic predictors of these diseases, in Pima...... Indians. There was no association of the Gly482Ser polymorphism with either type 2 diabetes or BMI (n = 984). However, among nondiabetic Pima Indians (n = 183-201), those with the Gly/Gly genotype had a lower mean insulin secretory response to intravenous and oral glucose and a lower mean rate of lipid...
CAR-mediated repression of Foxo1 transcriptional activity regulates the cell cycle inhibitor p21 in mouse livers

International Nuclear Information System (INIS)

Kazantseva, Yuliya A.; Yarushkin, Andrei A.; Pustylnyak, Vladimir O.

2014-01-01

Highlights: • CAR activation decreased the level of Foxo1 in mouse livers. • CAR activation decreased the level of p21 in mouse livers. • CAR activation inhibited Foxo1 transcriptional activity in mouse livers. - Abstract: 1,4-Bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP), an agonist of constitutive androstane receptor (CAR), is a well-known strong primary chemical mitogen for the mouse liver. Despite extensive investigation of the role of CAR in the regulation of cell proliferation, our knowledge of the intricate mediating mechanism is incomplete. In this study, we demonstrated that long-term CAR activation by TCPOBOP increased liver-to-body weight ratio and decreased tumour suppressor Foxo1 expression and transcriptional activity, which were correlated with reduced expression of genes regulated by Foxo1, including the cell-cycle inhibitor Cdkn1a(p21), and upregulation of the cell-cycle regulator Cyclin D1. Moreover, we demonstrated the negative regulatory effect of TCPOBOP-activated CAR on the association of Foxo1 with the target Foxo1 itself and Cdkn1a(p21) promoters. Thus, we identified CAR-mediated repression of cell cycle inhibitor p21, as mediated by repression of FOXO1 expression and transcriptional activity. CAR-FOXO1 cross-talk may provide new opportunities for understanding liver diseases and developing more effective therapeutic approaches to better drug treatments
Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) Pathway Is Induced by Mechanical Load and Reduces the Activity of Hedgehog Signaling in Chondrogenic Micromass Cell Cultures

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Juhász, Tamás; Szentléleky, Eszter; Szűcs Somogyi, Csilla; Takács, Roland; Dobrosi, Nóra; Engler, Máté; Tamás, Andrea; Reglődi, Dóra; Zákány, Róza

2015-01-01

Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurohormone exerting protective function during various stress conditions either in mature or developing tissues. Previously we proved the presence of PACAP signaling elements in chicken limb bud-derived chondrogenic cells in micromass cell cultures. Since no data can be found if PACAP signaling is playing any role during mechanical stress in any tissues, we aimed to investigate its contribution in mechanotransduction during chondrogenesis. Expressions of the mRNAs of PACAP and its major receptor, PAC1 increased, while that of other receptors, VPAC1, VPAC2 decreased upon mechanical stimulus. Mechanical load enhanced the expression of collagen type X, a marker of hypertrophic differentiation of chondrocytes and PACAP addition attenuated this elevation. Moreover, exogenous PACAP also prevented the mechanical load evoked activation of hedgehog signaling: protein levels of Sonic and Indian Hedgehogs and Gli1 transcription factor were lowered while expressions of Gli2 and Gli3 were elevated by PACAP application during mechanical load. Our results suggest that mechanical load activates PACAP signaling and exogenous PACAP acts against the hypertrophy inducing effect of mechanical load. PMID:26230691
Pituitary Adenylate Cyclase Activating Polypeptide (PACAP Pathway Is Induced by Mechanical Load and Reduces the Activity of Hedgehog Signaling in Chondrogenic Micromass Cell Cultures

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Tamás Juhász

2015-07-01

Full Text Available Pituitary adenylate cyclase activating polypeptide (PACAP is a neurohormone exerting protective function during various stress conditions either in mature or developing tissues. Previously we proved the presence of PACAP signaling elements in chicken limb bud-derived chondrogenic cells in micromass cell cultures. Since no data can be found if PACAP signaling is playing any role during mechanical stress in any tissues, we aimed to investigate its contribution in mechanotransduction during chondrogenesis. Expressions of the mRNAs of PACAP and its major receptor, PAC1 increased, while that of other receptors, VPAC1, VPAC2 decreased upon mechanical stimulus. Mechanical load enhanced the expression of collagen type X, a marker of hypertrophic differentiation of chondrocytes and PACAP addition attenuated this elevation. Moreover, exogenous PACAP also prevented the mechanical load evoked activation of hedgehog signaling: protein levels of Sonic and Indian Hedgehogs and Gli1 transcription factor were lowered while expressions of Gli2 and Gli3 were elevated by PACAP application during mechanical load. Our results suggest that mechanical load activates PACAP signaling and exogenous PACAP acts against the hypertrophy inducing effect of mechanical load.
Histone variant H2A.Z antagonizes the positive effect of the transcriptional activator CPC1 to regulate catalase-3 expression under normal and oxidative stress conditions.

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Dong, Qing; Wang, Yajun; Qi, Shaohua; Gai, Kexin; He, Qun; Wang, Ying

2018-05-05

In eukaryotes, deposition of the histone variant H2A.Z into nucleosomes through the chromatin remodeling complex, SWR1, is a crucial step in modulating gene transcription. Recently, H2A.Z has been shown to control the expression of responsive genes, but the underlying mechanism of how H2A.Z responds to physiological stimuli is not well understood. Here, we reveal that, in Neurospora crassa, H2A.Z is a negative regulator of catalase-3 gene, which is responsible for resistance to oxidative stress. H2A.Z represses cat-3 gene expression through direct incorporation at cat-3 locus in a SWR1 complex dependent pathway. Notably, loss of H2A.Z or SWR1 subunits leads to increased binding of a transcription factor, CPC1, at cat-3 locus. Additionally, introduction of plasmids containing gene encoding H2A.Z or SWR1 complex subunits into wild-type strains decreased CAT-3 expression, indicating that H2A.Z counteracts the positive effect of CPC1 to achieve low level cat-3 expression under non-inductive condition. Furthermore, upon oxidative stress, H2A.Z is rapidly evicted from cat-3 locus for the recruitment of CPC1, resulting in robust and full cat-3 gene expression in response to external stimuli. Collectively, this study strongly demonstrates that H2A.Z antagonizes the function of transcription factor to regulate responsive gene transcription under normal conditions and to poise for gene full activation under oxidative stress. Copyright © 2018. Published by Elsevier Inc.
The Transcription Profile of Tax-3 Is More Similar to Tax-1 than Tax-2: Insights into HTLV-3 Potential Leukemogenic Properties

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Chevalier, Sébastien A.; Durand, Stéphanie; Dasgupta, Arindam; Radonovich, Michael; Cimarelli, Andrea; Brady, John N.

2012-01-01

Human T-cell Lymphotropic Viruses type 1 (HTLV-1) is the etiological agent of Adult T-cell Leukemia/Lymphoma. Although associated with lymphocytosis, HTLV-2 infection is not associated with any malignant hematological disease. Similarly, no infection-related symptom has been detected in HTLV-3-infected individuals studied so far. Differences in individual Tax transcriptional activity might account for these distinct physiopathological outcomes. Tax-1 and Tax-3 possess a PDZ binding motif in their sequence. Interestingly, this motif, which is critical for Tax-1 transforming activity, is absent from Tax-2. We used the DNA microarray technology to analyze and compare the global gene expression profiles of different T- and non T-cell types expressing Tax-1, Tax-2 or Tax-3 viral transactivators. In a T-cell line, this analysis allowed us to identify 48 genes whose expression is commonly affected by all Tax proteins and are hence characteristic of the HTLV infection, independently of the virus type. Importantly, we also identified a subset of genes (n = 70) which are specifically up-regulated by Tax-1 and Tax-3, while Tax-1 and Tax-2 shared only 1 gene and Tax-2 and Tax-3 shared 8 genes. These results demonstrate that Tax-3 and Tax-1 are closely related in terms of cellular gene deregulation. Analysis of the molecular interactions existing between those Tax-1/Tax-3 deregulated genes then allowed us to highlight biological networks of genes characteristic of HTLV-1 and HTLV-3 infection. The majority of those up-regulated genes are functionally linked in biological processes characteristic of HTLV-1-infected T-cells expressing Tax such as regulation of transcription and apoptosis, activation of the NF-κB cascade, T-cell mediated immunity and induction of cell proliferation and differentiation. In conclusion, our results demonstrate for the first time that, in T- and non T-cells types, Tax-3 is a functional analogue of Tax-1 in terms of transcriptional activation and
Proto-oncogene FBI-1 (Pokemon) and SREBP-1 Synergistically Activate Transcription of Fatty-acid Synthase Gene (FASN)*S⃞

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Choi, Won-Il; Jeon, Bu-Nam; Park, Hyejin; Yoo, Jung-Yoon; Kim, Yeon-Sook; Koh, Dong-In; Kim, Myung-Hwa; Kim, Yu-Ri; Lee, Choong-Eun; Kim, Kyung-Sup; Osborne, Timothy F.; Hur, Man-Wook

2008-01-01

FBI-1 (Pokemon/ZBTB7A) is a proto-oncogenic transcription factor of the BTB/POZ (bric-à-brac, tramtrack, and broad complex and pox virus zinc finger) domain family. Recent evidence suggested that FBI-1 might be involved in adipogenic gene expression. Coincidentally, expression of FBI-1 and fatty-acid synthase (FASN) genes are often increased in cancer and immortalized cells. Both FBI-1 and FASN are important in cancer cell proliferation. SREBP-1 is a major regulator of many adipogenic genes, and FBI-1 and SREBP-1 (sterol-responsive element (SRE)-binding protein 1) interact with each other directly via their DNA binding domains. FBI-1 enhanced the transcriptional activation of SREBP-1 on responsive promoters, pGL2-6x(SRE)-Luc and FASN gene. FBI-1 and SREBP-1 synergistically activate transcription of the FASN gene by acting on the proximal GC-box and SRE/E-box. FBI-1, Sp1, and SREBP-1 can bind to all three SRE, GC-box, and SRE/E-box. Binding competition among the three transcription factors on the GC-box and SRE/E-box appears important in the transcription regulation. FBI-1 is apparently changing the binding pattern of Sp1 and SREBP-1 on the two elements in the presence of induced SREBP-1 and drives more Sp1 binding to the proximal promoter with less of an effect on SREBP-1 binding. The changes induced by FBI-1 appear critical in the synergistic transcription activation. The molecular mechanism revealed provides insight into how proto-oncogene FBI-1 may attack the cellular regulatory mechanism of FASN gene expression to provide more phospholipid membrane components needed for rapid cancer cell proliferation. PMID:18682402
Hedgehog-GLI signaling drives self-renewal and tumorigenicity of human melanoma-initiating cells.

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Santini, Roberta; Vinci, Maria C; Pandolfi, Silvia; Penachioni, Junia Y; Montagnani, Valentina; Olivito, Biagio; Gattai, Riccardo; Pimpinelli, Nicola; Gerlini, Gianni; Borgognoni, Lorenzo; Stecca, Barbara

2012-09-01

The question of whether cancer stem/tumor-initiating cells (CSC/TIC) exist in human melanomas has arisen in the last few years. Here, we have used nonadherent spheres and the aldehyde dehydrogenase (ALDH) enzymatic activity to enrich for CSC/TIC in a collection of human melanomas obtained from a broad spectrum of sites and stages. We find that melanomaspheres display extensive in vitro self-renewal ability and sustain tumor growth in vivo, generating human melanoma xenografts that recapitulate the phenotypic composition of the parental tumor. Melanomaspheres express high levels of Hedgehog (HH) pathway components and of embryonic pluripotent stem cell factors SOX2, NANOG, OCT4, and KLF4. We show that human melanomas contain a subset of cells expressing high ALDH activity (ALDH(high)), which is endowed with higher self-renewal and tumorigenic abilities than the ALDH(low) population. A good correlation between the number of ALDH(high) cells and sphere formation efficiency was observed. Notably, both pharmacological inhibition of HH signaling by the SMOOTHENED (SMO) antagonist cyclopamine and GLI antagonist GANT61 and stable expression of shRNA targeting either SMO or GLI1 result in a significant decrease in melanoma stem cell self-renewal in vitro and a reduction in the number of ALDH(high) melanoma stem cells. Finally, we show that interference with the HH-GLI pathway through lentiviral-mediated silencing of SMO and GLI1 drastically diminishes tumor initiation of ALDH(high) melanoma stem cells. In conclusion, our data indicate an essential role of the HH-GLI1 signaling in controlling self-renewal and tumor initiation of melanoma CSC/TIC. Targeting HH-GLI1 is thus predicted to reduce the melanoma stem cell compartment. Copyright © 2012 AlphaMed Press.
AREB1, AREB2, and ABF3 are master transcription factors that cooperatively regulate ABRE-dependent ABA signaling involved in drought stress tolerance and require ABA for full activation.

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Yoshida, Takuya; Fujita, Yasunari; Sayama, Hiroko; Kidokoro, Satoshi; Maruyama, Kyonoshin; Mizoi, Junya; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

2010-02-01

A myriad of drought stress-inducible genes have been reported, and many of these are activated by abscisic acid (ABA). In the promoter regions of such ABA-regulated genes, conserved cis-elements, designated ABA-responsive elements (ABREs), control gene expression via bZIP-type AREB/ABF transcription factors. Although all three members of the AREB/ABF subfamily, AREB1, AREB2, and ABF3, are upregulated by ABA and water stress, it remains unclear whether these are functional homologs. Here, we report that all three AREB/ABF transcription factors require ABA for full activation, can form hetero- or homodimers to function in nuclei, and can interact with SRK2D/SnRK2.2, an SnRK2 protein kinase that was identified as a regulator of AREB1. Along with the tissue-specific expression patterns of these genes and the subcellular localization of their encoded proteins, these findings clearly indicate that AREB1, AREB2, and ABF3 have largely overlapping functions. To elucidate the role of these AREB/ABF transcription factors, we generated an areb1 areb2 abf3 triple mutant. Large-scale transcriptome analysis, which showed that stress-responsive gene expression is remarkably impaired in the triple mutant, revealed novel AREB/ABF downstream genes in response to water stress, including many LEA class and group-Ab PP2C genes and transcription factors. The areb1 areb2 abf3 triple mutant is more resistant to ABA than are the other single and double mutants with respect to primary root growth, and it displays reduced drought tolerance. Thus, these results indicate that AREB1, AREB2, and ABF3 are master transcription factors that cooperatively regulate ABRE-dependent gene expression for ABA signaling under conditions of water stress.
Valproic acid treatment response in vitro is determined by TP53 status in medulloblastoma.

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Mascaro-Cordeiro, Bruna; Oliveira, Indhira Dias; Tesser-Gamba, Francine; Pavon, Lorena Favaro; Saba-Silva, Nasjla; Cavalheiro, Sergio; Dastoli, Patrícia; Toledo, Silvia Regina Caminada

2018-05-22

Histone deacetylate inhibitors (HDACi), as valproic acid (VA), have been reported to enhance efficacy and to prevent drug resistance in some tumors, including medulloblastoma (MB). In the present study, we investigated VA role, combined to cisplatin (CDDP) in cell viability and gene expression of MB cell lines. Dose-response curve determined IC 50 values for each treatment: (1) VA single, (2) CDDP single, and (3) VA and CDDP combined. Cytotoxicity and flow cytometry evaluated cell viability after exposure to treatments. Quantitative PCR evaluated gene expression levels of AKT, CTNNB1, GLI1, KDM6A, KDM6B, NOTCH2, PTCH1, and TERT, before and after treatment. Besides, we performed next-generation sequencing (NGS) for PTCH1, TERT, and TP53 genes. The most effective treatment to reduce viability was combined for D283MED and ONS-76; and CDDP single for DAOY cells (p AKT genes were overexpressed after treatments with VA. D283MED and ONS-76 cells presented variants in TERT and PTCH1, respectively and DAOY cell line presented a TP53 mutation. MB tumors belonging to SHH molecular subgroup, with TP53 MUT , would be the ones that present high risk in relation to VA use during the treatment, while TP53 WT MBs can benefit from VA therapy, both SHH and groups 3 and 4. Our study shows a new perspective about VA action in medulloblastoma cells, raising the possibility that VA may act in different patterns. According to the genetic background of MB cell, VA can stimulate cell cycle arrest and apoptosis or induce resistance to treatment via signaling pathways activation.
Zinc coordination is required for and regulates transcription activation by Epstein-Barr nuclear antigen 1.

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Siddhesh Aras

2009-06-01

Full Text Available Epstein-Barr Nuclear Antigen 1 (EBNA1 is essential for Epstein-Barr virus to immortalize naïve B-cells. Upon binding a cluster of 20 cognate binding-sites termed the family of repeats, EBNA1 transactivates promoters for EBV genes that are required for immortalization. A small domain, termed UR1, that is 25 amino-acids in length, has been identified previously as essential for EBNA1 to activate transcription. In this study, we have elucidated how UR1 contributes to EBNA1's ability to transactivate. We show that zinc is necessary for EBNA1 to activate transcription, and that UR1 coordinates zinc through a pair of essential cysteines contained within it. UR1 dimerizes upon coordinating zinc, indicating that EBNA1 contains a second dimerization interface in its amino-terminus. There is a strong correlation between UR1-mediated dimerization and EBNA1's ability to transactivate cooperatively. Point mutants of EBNA1 that disrupt zinc coordination also prevent self-association, and do not activate transcription cooperatively. Further, we demonstrate that UR1 acts as a molecular sensor that regulates the ability of EBNA1 to activate transcription in response to changes in redox and oxygen partial pressure (pO(2. Mild oxidative stress mimicking such environmental changes decreases EBNA1-dependent transcription in a lymphoblastoid cell-line. Coincident with a reduction in EBNA1-dependent transcription, reductions are observed in EBNA2 and LMP1 protein levels. Although these changes do not affect LCL survival, treated cells accumulate in G0/G1. These findings are discussed in the context of EBV latency in body compartments that differ strikingly in their pO(2 and redox potential.
The first N-terminal unprotected (Gly-Aib)n peptide: H-Gly-Aib-Gly-Aib-OtBu.

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Gessmann, Renate; Brückner, Hans; Petratos, Kyriacos

2015-12-01

Glycine (Gly) is incorporated in roughly half of all known peptaibiotic (nonribosomally biosynthesized antibiotic peptides of fungal origin) sequences and is the residue with the greatest conformational flexibility. The conformational space of Aib (α-aminoisobutyric acid) is severely restricted by the second methyl group attached to the Cα atom. Most of the crystal structures containing Aib are N-terminal protected. Deprotection of the N- or C-terminus of peptides may alter the hydrogen-bonding scheme and/or the structure and may facilitate crystallization. The structure reported here for glycyl-α-aminoisobutyrylglycyl-α-aminoisobutyric acid tert-butyl ester, C16H30N4O5, describes the first N-terminal-unprotected (Gly-Aib)n peptide. The achiral peptide could form an intramolecular hydrogen bond between the C=O group of Gly1 and the N-H group of Aib4. This hydrogen bond is found in all tetrapeptides and N-terminal-protected tripeptides containing Aib, apart from one exception. In the present work, this hydrogen bond is not observed (N...O = 5.88 Å). Instead, every molecule is hydrogen bonded to six other symmetry-related molecules with a total of eight hydrogen bonds per molecule. The backbone conformation starts in the right-handed helical region (and the left-handed helical region for the inverted molecule) and reverses the screw sense in the last two residues.

The Gly482Ser genotype at the PPARGC1A gene and elevated blood pressure: a meta-analysis involving 13,949 individuals

DEFF Research Database (Denmark)

Vimaleswaran, Karani Santhanakrishnan; Luan, Jian'an; Andersen, Gitte

2008-01-01

The protein encoded by the PPARGC1A gene is expressed at high levels in metabolically active tissues and is involved in the control of oxidative stress via reactive oxygen species detoxification. Several recent reports suggest that the PPARGC1A Gly482Ser (rs8192678) missense polymorphism may relate...... inversely with blood pressure. We used conventional meta-analysis methods to assess the association between Gly482Ser and systolic (SBP) or diastolic blood pressures (DBP) or hypertension in 13,949 individuals from 17 studies, of which 6,042 were previously unpublished observations. The studies comprised...
Synthesis and Characterization of Novel Acyl-Glycine Inhibitors of GlyT2.

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Mostyn, Shannon N; Carland, Jane E; Shimmon, Susan; Ryan, Renae M; Rawling, Tristan; Vandenberg, Robert J

2017-09-20

It has been demonstrated previously that the endogenous compound N-arachidonyl-glycine inhibits the glycine transporter GlyT2, stimulates glycinergic neurotransmission, and provides analgesia in animal models of neuropathic and inflammatory pain. However, it is a relatively weak inhibitor with an IC 50 of 9 μM and is subject to oxidation via cyclooxygenase, limiting its therapeutic value. In this paper we describe the synthesis and testing of a novel series of monounsaturated C18 and C16 acyl-glycine molecules as inhibitors of the glycine transporter GlyT2. We demonstrate that they are up to 28 fold more potent that N-arachidonyl-glycine with no activity at the closely related GlyT1 transporter at concentrations up to 30 μM. This novel class of compounds show considerable promise as a first generation of GlyT2 transport inhibitors.
A single-repeat R3-MYB transcription factor MYBC1 negatively regulates freezing tolerance in Arabidopsis

International Nuclear Information System (INIS)

Zhai, Hong; Bai, Xi; Zhu, Yanming; Li, Yong; Cai, Hua; Ji, Wei; Ji, Zuojun; Liu, Xiaofei; Liu, Xin; Li, Jing

2010-01-01

We had previously identified the MYBC1 gene, which encodes a single-repeat R3-MYB protein, as a putative osmotic responding gene; however, no R3-MYB transcription factor has been reported to regulate osmotic stress tolerance. Thus, we sought to elucidate the function of MYBC1 in response to osmotic stresses. Real-time RT-PCR analysis indicated that MYBC1 expression responded to cold, dehydration, salinity and exogenous ABA at the transcript level. mybc1 mutants exhibited an increased tolerance to freezing stress, whereas 35S::MYBC1 transgenic plants exhibited decreased cold tolerance. Transcript levels of some cold-responsive genes, including CBF/DREB genes, KIN1, ADC1, ADC2 and ZAT12, though, were not altered in the mybc1 mutants or the 35S::MYBC1 transgenic plants in response to cold stress, as compared to the wild type. Microarray analysis results that are publically available were investigated and found transcript level of MYBC1 was not altered by overexpression of CBF1, CBF2, and CBF3, suggesting that MYBC1 is not down regulated by these CBF family members. Together, these results suggested that MYBC1is capable of negatively regulating the freezing tolerance of Arabidopsis in the CBF-independent pathway. In transgenic Arabidopsis carrying an MYBC1 promoter driven β-glucuronidase (GUS) construct, GUS activity was observed in all tissues and was relatively stronger in the vascular tissues. Fused MYBC1 and GFP protein revealed that MYBC1 was localized exclusively in the nuclear compartment.
Downregulation of RND3/RhoE in glioblastoma patients promotes tumorigenesis through augmentation of notch transcriptional complex activity

International Nuclear Information System (INIS)

Liu, Baohui; Lin, Xi; Yang, Xiangsheng; Dong, Huimin; Yue, Xiaojing; Andrade, Kelsey C; Guo, Zhentao; Yang, Jian; Wu, Liquan; Zhu, Xiaonan; Zhang, Shenqi; Tian, Daofeng; Wang, Junmin; Cai, Qiang; Chen, Qizuan; Mao, Shanping; Chen, Qianxue; Chang, Jiang

2015-01-01

Activation of Notch signaling contributes to glioblastoma multiform (GBM) tumorigenesis. However, the molecular mechanism that promotes the Notch signaling augmentation during GBM genesis remains largely unknown. Identification of new factors that regulate Notch signaling is critical for tumor treatment. The expression levels of RND3 and its clinical implication were analyzed in GBM patients. Identification of RND3 as a novel factor in GBM genesis was demonstrated in vitro by cell experiments and in vivo by a GBM xenograft model. We found that RND3 expression was significantly decreased in human glioblastoma. The levels of RND3 expression were inversely correlated with Notch activity, tumor size, and tumor cell proliferation, and positively correlated with patient survival time. We demonstrated that RND3 functioned as an endogenous repressor of the Notch transcriptional complex. RND3 physically interacted with NICD, CSL, and MAML1, the Notch transcriptional complex factors, promoted NICD ubiquitination, and facilitated the degradation of these cofactor proteins. We further revealed that RND3 facilitated the binding of NICD to FBW7, a ubiquitin ligase, and consequently enhanced NICD protein degradation. Therefore, Notch transcriptional activity was inhibited. Forced expression of RND3 repressed Notch signaling, which led to the inhibition of glioblastoma cell proliferation in vitro and tumor growth in the xenograft mice in vivo. Downregulation of RND3, however, enhanced Notch signaling activity, and subsequently promoted glioma cell proliferation. Inhibition of Notch activity abolished RND3 deficiency-mediated GBM cell proliferation. We conclude that downregulation of RND3 is responsible for the enhancement of Notch activity that promotes glioblastoma genesis
Polymorphisms in signal transducer and activator of transcription 3 and lung function in asthma

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Lazarus Ross

2005-06-01

Full Text Available Abstract Background Identifying genetic determinants for lung function is important in providing insight into the pathophysiology of asthma. Signal transducer and activator of transcription 3 is a transcription factor latent in the cytoplasm; the gene (STAT3 is activated by a wide range of cytokines, and may play a role in lung development and asthma pathogenesis. Methods We genotyped six single nucleotide polymorphisms (SNPs in the STAT3 gene in a cohort of 401 Caucasian adult asthmatics. The associations between each SNP and forced expiratory volume in 1 second (FEV1, as a percent of predicted, at the baseline exam were tested using multiple linear regression models. Longitudinal analyses involving repeated measures of FEV1 were conducted with mixed linear models. Haplotype analyses were conducted using imputed haplotypes. We completed a second association study by genotyping the same six polymorphisms in a cohort of 652 Caucasian children with asthma. Results We found that three polymorphisms were significantly associated with baseline FEV1: homozygotes for the minor alleles of each polymorphism had lower FEV1 than homozygotes for the major alleles. Moreover, these associations persisted when we performed an analysis on repeated measures of FEV1 over 8 weeks. A haplotypic analysis based on the six polymorphisms indicated that two haplotypes were associated with baseline FEV1. Among the childhood asthmatics, one polymorphism was associated with both baseline FEV1 and the repeated measures of FEV1 over 4 years. Conclusion Our results indicate that genetic variants in STAT3, independent of asthma treatment, are determinants of FEV1 in both adults and children with asthma, and suggest that STAT3 may participate in inflammatory pathways that have an impact on level of lung function.
Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

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Kroes, R A; Abravaya, K; Seidenfeld, J; Morimoto, R I

1991-01-01

Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or beta-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes. Images PMID:2052560
LncRNA MEG3 downregulation mediated by DNMT3b contributes to nickel malignant transformation of human bronchial epithelial cells via modulating PHLPP1 transcription and HIF-1α translation.

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Zhou, C; Huang, C; Wang, J; Huang, H; Li, J; Xie, Q; Liu, Y; Zhu, J; Li, Y; Zhang, D; Zhu, Q; Huang, C

2017-07-06

Long noncoding RNAs (lncRNAs) are emerging as key factors in various fundamental cellular biological processes, and many of them are likely to have functional roles in tumorigenesis. Maternally expressed gene 3 (MEG3) is an imprinted gene located at 14q32 that encodes a lncRNA, and the decreased MEG3 expression has been reported in multiple cancer tissues. However, nothing is known about the alteration and role of MEG3 in environmental carcinogen-induced lung tumorigenesis. Our present study, for the first time to the best of our knowledge, discovered that environmental carcinogen nickel exposure led to MEG3 downregulation, consequently initiating c-Jun-mediated PHLPP1 transcriptional inhibition and hypoxia-inducible factor-1α (HIF-1α) protein translation upregulation, in turn resulting in malignant transformation of human bronchial epithelial cells. Mechanistically, MEG3 downregulation was attributed to nickel-induced promoter hypermethylation via elevating DNMT3b expression, whereas PHLPP1 transcriptional inhibition was due to the decreasing interaction of MEG3 with its inhibitory transcription factor c-Jun. Moreover, HIF-1α protein translation was upregulated via activating the Akt/p70S6K/S6 axis resultant from PHLPP1 inhibition in nickel responses. Collectively, we uncover that nickel exposure results in DNMT3b induction and MEG3 promoter hypermethylation and expression inhibition, further reduces its binding to c-Jun and in turn increasing c-Jun inhibition of PHLPP1 transcription, leading to the Akt/p70S6K/S6 axis activation, and HIF-1α protein translation, as well as malignant transformation of human bronchial epithelial cells. Our studies provide a significant insight into understanding the alteration and role of MEG3 in nickel-induced lung tumorigenesis.
The HIV-1 transcriptional activator Tat has potent nucleic acid chaperoning activities in vitro.

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Kuciak, Monika; Gabus, Caroline; Ivanyi-Nagy, Roland; Semrad, Katharina; Storchak, Roman; Chaloin, Olivier; Muller, Sylviane; Mély, Yves; Darlix, Jean-Luc

2008-06-01

The human immunodeficiency virus type 1 (HIV-1) is a primate lentivirus that causes the acquired immunodeficiency syndrome (AIDS). In addition to the virion structural proteins and enzyme precursors, that are Gag, Env and Pol, HIV-1 encodes several regulatory proteins, notably a small nuclear transcriptional activator named Tat. The Tat protein is absolutely required for virus replication since it controls proviral DNA transcription to generate the full-length viral mRNA. Tat can also regulate mRNA capping and splicing and was recently found to interfere with the cellular mi- and siRNA machinery. Because of its extensive interplay with nucleic acids, and its basic and disordered nature we speculated that Tat had nucleic acid-chaperoning properties. This prompted us to examine in vitro the nucleic acid-chaperoning activities of Tat and Tat peptides made by chemical synthesis. Here we report that Tat has potent nucleic acid-chaperoning activities according to the standard DNA annealing, DNA and RNA strand exchange, RNA ribozyme cleavage and trans-splicing assays. The active Tat(44-61) peptide identified here corresponds to the smallest known sequence with DNA/RNA chaperoning properties.
Structure-activity relationship of linear peptide Bu-His-DPhe-Arg-Trp-Gly-NH(2) at the human melanocortin-1 and -4 receptors: arginine substitution.

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Cheung, Adrian Wai-Hing; Danho, Waleed; Swistok, Joseph; Qi, Lida; Kurylko, Grazyna; Franco, Lucia; Yagaloff, Keith; Chen, Li

2002-09-02

A series of pentapeptides, based on Bu-His(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-NH(2) and modified at the Arg(8) position, was prepared and pharmacologically characterized. Peptides containing either cyanoguanidine or acylguanidine, two substantially less basic arginine surrogates, were found to retain the agonist activity of the parent peptide at both hMC1R and hMC4R. This study unequivocally shows that the positive charge of Arg(8) is not essential for efficient interactions of our pentapeptide with both hMC1R and hMC4R.
[Regulation of [12Asp]K-ras4B on transcriptional activity of estrogen receptor in endometrial carcinoma HEC-1A cell lines].

Science.gov (United States)

Gui, Li-ming; Wei, Li-hui; Xu, Ming-xu; Wang, Jian-liu; Zhong, Ying-cheng; Li, Xiao-ping; Tu, Zheng; Sun, Peng-ming; Ma, Da-long

2004-01-01

To investigate the effect of mutant-type [(12)Asp]K-ras4B gene on the expression of estrogen receptor (ER) alpha and beta and their transcriptional activity as a transcription factor in endometrial carcinoma HEC-1A cell line. (1) Effect of [(12)Asp]K-ras4B on the expression of ER alpha and beta were determined using Western blot assay. (2) Eukaryotic expression plasmid pGL3-luciferase-ERE containing luciferase report gene and estrogen receptor element (ERE) was constructed, and co-transfected into NIH3T3 and HEC-1A cell lines with pEGFP-N1 to examine the effect of [(12)Asp]K-ras4B on ER transcription that is regulated by estradiol. In addition, they were transfected into pSV5-HER0 (containing full length wide type ERalpha cDNA) and pCMV-rafS621A (inhibiting raf kinase) plasmids to test the effect of [(12)Asp]K-ras4B/raf signal pathway on transcriptional activity of ER proteins. (1) Protein level of ERs expressed in pcDI transfected control cells was low while it was increased for 3.6-fold (97 +/- 25, 349 +/- 67, P ras4B NIH3T3 cells after transfection. (2) In pcDI-[(12)Asp]K-ras4B NIH3T3 cells, the ratios for ERalpha and and ERbeta levels before transfection of rafS621A plasmids to that after the transfection, were 2.4:1 (724 +/- 45, 310 +/- 46, P HEC-1A cells, these ratios were 2.1:1 (566 +/- 22, 279 +/- 30, P ras4B NIH3T3 cells, 19-fold (141 +/- 39, 2644 +/- 331, P HEC-1A cells, respectively, when compared with those in the absence of E(2). (4) In pSV5-HER0 transfected pcDI-[(12)Asp] K-ras4B NIH3T3 cells and HEC-1A cells, compared to the untransfected cells, the ER transcriptional activity in the transfected cells increased markedly. The luciferase activity was increased for 8-fold (1048 +/- 91, 8099 +/- 452, P HEC-1A cells and pcDI-[(12)Asp]K-ras4B NIH3T3 cells. The ratio of luciferase activities in pcDI-[(12)Asp]K-ras4B NIH3T3 and HEC-1A cells, before and after transfection was 7.8:1 (1184 +/- 168, 152 +/- 27, P ras4B can enhance the expression of ERalpha and
X-linked Alport syndrome associated with a synonymous p.Gly292Gly mutation alters the splicing donor site of the type IV collagen alpha chain 5 gene.

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Fu, Xue Jun; Nozu, Kandai; Eguchi, Aya; Nozu, Yoshimi; Morisada, Naoya; Shono, Akemi; Taniguchi-Ikeda, Mariko; Shima, Yuko; Nakanishi, Koichi; Vorechovsky, Igor; Iijima, Kazumoto

2016-10-01

X-linked Alport syndrome (XLAS) is a progressive hereditary nephropathy caused by mutations in the type IV collagen alpha chain 5 gene (COL4A5). Although many COL4A5 mutations have previously been identified, pathogenic synonymous mutations have not yet been described. A family with XLAS underwent mutational analyses of COL4A5 by PCR and direct sequencing, as well as transcript analysis of potential splice site mutations. In silico analysis was also conducted to predict the disruption of splicing factor binding sites. Immunohistochemistry (IHC) of kidney biopsies was used to detect α2 and α5 chain expression. We identified a hemizygous point mutation, c.876A>T, in exon 15 of COL4A5 in the proband and his brother, which is predicted to result in a synonymous amino acid change, p.(Gly292Gly). Transcript analysis showed that this mutation potentially altered splicing because it disrupted the splicing factor binding site. The kidney biopsy of the proband showed lamellation of the glomerular basement membrane (GBM), while IHC revealed negative α5(IV) staining in the GBM and Bowman's capsule, which is typical of XLAS. This is the first report of a synonymous COL4A5 substitution being responsible for XLAS. Our findings suggest that transcript analysis should be conducted for the future correct assessment of silent mutations.
KDM1A triggers androgen-induced miRNA transcription via H3K4me2 demethylation and DNA oxidation.

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Yang, Shu; Zhang, Jiyuan; Zhang, Yalong; Wan, Xuechao; Zhang, Congzhe; Huang, Xiaohui; Huang, Wenhua; Pu, Honglei; Pei, Chaohan; Wu, Hai; Huang, Yan; Huang, Shengdong; Li, Yao

2015-06-15

Androgen receptor (AR) is a ligand dependent transcription factor that regulates the transcription of target genes. AR activity is closely involved in the maintenance and progression of prostate cancer. After the binding with androgen, AR moves into nucleus and binds to DNA sequence containing androgen response elements (ARE). Flavin-dependent monoamine oxidase KDM1A is necessary for AR driven transcription while the mechanism remains unclear. The association between androgen-dependent transcription and oxidation was tested through pharmaceutical inhibitions and siRNA knockdown of DNA oxidation repair components in prostate cancer cells. The recruitment of involved proteins and the histone methylation dynamics on ARE region was explored by chromatin immunoprecipitation (ChIP). Oxidation inhibition reduced AR dependent expression of KLK3, TMPRSS2, hsa-miR-125b2, and hsa-miR-133b. And such reduction could be restored by H2 O2 treatment. KDM1A recruitment and H3K4me2 demethylation on ARE regions, which produce H2 O2 , are associated with AR targets transcription. AR targets transcription and coupled oxidation recruit 8-oxoguanine-DNA glycosylase (OGG1) and the nuclease APEX1 to ARE regions. Such recruitment depends on KDM1A, and is necessary for AR targets transcription. Our work underlined the importance of histone demethylation and DNA oxidation/repairing machinery in androgen-dependent transcription. The present finds have implications for research into new druggable targets for prostate cancer relying on the cascade of AR activity regulation. © 2015 Wiley Periodicals, Inc.
The RNA Exosome Adaptor ZFC3H1 Functionally Competes with Nuclear Export Activity to Retain Target Transcripts

DEFF Research Database (Denmark)

Silla, Toomas; Karadoulama, Evdoxia; Mąkosa, Dawid

2018-01-01

, containing polyadenylated (pA+) RNA secluded from nucleocytoplasmic export. We asked whether exosome co-factors could serve such nuclear retention. Co-localization studies revealed the enrichment of pA+ RNA foci with "pA-tail exosome targeting (PAXT) connection" components MTR4, ZFC3H1, and PABPN1......Mammalian genomes are promiscuously transcribed, yielding protein-coding and non-coding products. Many transcripts are short lived due to their nuclear degradation by the ribonucleolytic RNA exosome. Here, we show that abolished nuclear exosome function causes the formation of distinct nuclear foci...... but no overlap with known nuclear structures such as Cajal bodies, speckles, paraspeckles, or nucleoli. Interestingly, ZFC3H1 is required for foci formation, and in its absence, selected pA+ RNAs, including coding and non-coding transcripts, are exported to the cytoplasm in a process dependent on the mRNA export...
DNA Binding by the Ribosomal DNA Transcription Factor Rrn3 Is Essential for Ribosomal DNA Transcription*

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Stepanchick, Ann; Zhi, Huijun; Cavanaugh, Alice H.; Rothblum, Katrina; Schneider, David A.; Rothblum, Lawrence I.

2013-01-01

The human homologue of yeast Rrn3 is an RNA polymerase I-associated transcription factor that is essential for ribosomal DNA (rDNA) transcription. The generally accepted model is that Rrn3 functions as a bridge between RNA polymerase I and the transcription factors bound to the committed template. In this model Rrn3 would mediate an interaction between the mammalian Rrn3-polymerase I complex and SL1, the rDNA transcription factor that binds to the core promoter element of the rDNA. In the course of studying the role of Rrn3 in recruitment, we found that Rrn3 was in fact a DNA-binding protein. Analysis of the sequence of Rrn3 identified a domain with sequence similarity to the DNA binding domain of heat shock transcription factor 2. Randomization, or deletion, of the amino acids in this region in Rrn3, amino acids 382–400, abrogated its ability to bind DNA, indicating that this domain was an important contributor to DNA binding by Rrn3. Control experiments demonstrated that these mutant Rrn3 constructs were capable of interacting with both rpa43 and SL1, two other activities demonstrated to be essential for Rrn3 function. However, neither of these Rrn3 mutants was capable of functioning in transcription in vitro. Moreover, although wild-type human Rrn3 complemented a yeast rrn3-ts mutant, the DNA-binding site mutant did not. These results demonstrate that DNA binding by Rrn3 is essential for transcription by RNA polymerase I. PMID:23393135
DNA binding by the ribosomal DNA transcription factor rrn3 is essential for ribosomal DNA transcription.

Science.gov (United States)

Stepanchick, Ann; Zhi, Huijun; Cavanaugh, Alice H; Rothblum, Katrina; Schneider, David A; Rothblum, Lawrence I

2013-03-29

The human homologue of yeast Rrn3 is an RNA polymerase I-associated transcription factor that is essential for ribosomal DNA (rDNA) transcription. The generally accepted model is that Rrn3 functions as a bridge between RNA polymerase I and the transcription factors bound to the committed template. In this model Rrn3 would mediate an interaction between the mammalian Rrn3-polymerase I complex and SL1, the rDNA transcription factor that binds to the core promoter element of the rDNA. In the course of studying the role of Rrn3 in recruitment, we found that Rrn3 was in fact a DNA-binding protein. Analysis of the sequence of Rrn3 identified a domain with sequence similarity to the DNA binding domain of heat shock transcription factor 2. Randomization, or deletion, of the amino acids in this region in Rrn3, amino acids 382-400, abrogated its ability to bind DNA, indicating that this domain was an important contributor to DNA binding by Rrn3. Control experiments demonstrated that these mutant Rrn3 constructs were capable of interacting with both rpa43 and SL1, two other activities demonstrated to be essential for Rrn3 function. However, neither of these Rrn3 mutants was capable of functioning in transcription in vitro. Moreover, although wild-type human Rrn3 complemented a yeast rrn3-ts mutant, the DNA-binding site mutant did not. These results demonstrate that DNA binding by Rrn3 is essential for transcription by RNA polymerase I.
MicroR-146 blocks the activation of M1 macrophage by targeting signal transducer and activator of transcription 1 in hepatic schistosomiasis

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Xing He

2016-11-01

Full Text Available Schistosomiasis is a chronic disease caused by the parasite of the Schistosoma genus and is characterized by egg-induced hepatic granulomas and fibrosis. Macrophages play a central role in schistosomiasis with several studies highlighting their differentiation into M2 cells involved in the survival of infected mice through limitation of immunopathology. However, little is known regarding the mechanisms of regulating macrophage differentiation. Here, we showed that the early stage of infection by Schistosoma japonicum induced expression of type 1 T-helper-cell (Th1 cytokine, interferon-γ (IFN-γ, leading to increase in M1 cells. However, the presence of liver-trapped eggs induced the expression of Th2 cytokines including interleukin-4 (IL-4, IL-10, and IL-13 that upregulated the transcription of miR-146b by activating signal transducer and activator of transcription 3/6 (STAT3/6 that bind to the promoter of the pre-miR-146b gene. We found that the miR-146a/b was significantly upregulated in macrophages during the progression of hepatic schistosomiasis. The elevated miR-146a/b inhibited the IFN-γ-induced differentiation of macrophages to M1 cells through targeting STAT1. Our data indicate the protective roles of miR-146a/b in hepatic schistosomiasis through regulating the differentiation of macrophages into M2 cells.
Butyrate transcriptionally enhances peptide transporter PepT1 expression and activity.

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Guillaume Dalmasso

Full Text Available BACKGROUND: PepT1, an intestinal epithelial apical di/tripeptide transporter, is normally expressed in the small intestine and induced in colon during chronic inflammation. This study aimed at investigating PepT1 regulation by butyrate, a short-chain fatty acid produced by commensal bacteria and accumulated inside inflamed colonocyte. RESULTS: We found that butyrate treatment of human intestinal epithelial Caco2-BBE cells increased human PepT1 (hPepT1 promoter activity in a dose- and time-dependent manner, with maximal activity observed in cells treated with 5 mM butyrate for 24 h. Under this condition, hPepT1 promoter activity, mRNA and protein expression levels were increased as assessed by luciferase assay, real-time RT-PCR and Western blot, respectively. hPepT1 transport activity was accordingly increased by approximately 2.5-fold. Butyrate did not alter hPepT1 mRNA half-life indicating that butyrate acts at the transcriptional level. Molecular analyses revealed that Cdx2 is the most important transcription factor for butyrate-induced increase of hPepT1 expression and activity in Caco2-BBE cells. Butyrate-activated Cdx2 binding to hPepT1 promoter was confirmed by gel shift and chromatin immunoprecipitation. Moreover, Caco2-BBE cells overexpressing Cdx2 exhibited greater hPepT1 expression level than wild-type cells. Finally, treatment of mice with 5 mM butyrate added to drinking water for 24 h increased colonic PepT1 mRNA and protein expression levels, as well as enhanced PepT1 transport activity in colonic apical membranes vesicles. CONCLUSIONS: Collectively, our results demonstrate that butyrate increases PepT1 expression and activity in colonic epithelial cells, which provides a new understanding of PepT1 regulation during chronic inflammation.
Increased accumulation of hypoxia-inducible factor-1α with reduced transcriptional activity mediates the antitumor effect of triptolide

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Li Zheng

2010-10-01

Full Text Available Abstract Background Hypoxia-inducible factor-1α (HIF-1α, a critical transcription factor to reduced O2 availability, has been demonstrated to be extensively involved in tumor survival, aggressive progression, drug resistance and angiogenesis. Thus it has been considered as a potential anticancer target. Triptolide is the main principle responsible for the biological activities of the Traditional Chinese Medicine tripterygium wilfordii Hook F. Triptolide possesses great chemotherapy potential for cancer with its broad-spectrum anticancer, antiangiogenesis, and drug-resistance circumvention activities. Numerous biological molecules inhibited by triptolide have been viewed as its possible targets. However, the anticancer action mechanisms of triptolide remains to be further investigated. Here we used human ovarian SKOV-3 cancer cells as a model to probe the effect of triptolide on HIF-1α. Results Triptolide was observed to inhibit the proliferation of SKOV-3 cells, and meanwhile, to enhance the accumulation of HIF-1α protein in SKOV-3, A549 and DU145 cells under different conditions. Triptolide did not change the kinetics or nuclear localization of HIF-1α protein or the 26 S proteasome activity in SKOV-3 cells. However, triptolide was found to increase the levels of HIF-1α mRNA. Unexpectedly, the HIF-1α protein induced by triptolide appeared to lose its transcriptional activity, as evidenced by the decreased mRNA levels of its target genes including VEGF, BNIP3 and CAIX. The results were further strengthened by the lowered secretion of VEGF protein, the reduced sprout outgrowth from the rat aorta rings and the inhibitory expression of the hypoxia responsive element-driven luciferase reporter gene. Moreover, the silencing of HIF-1α partially prevented the cytotoxicity and apoptosis triggered by triptolide. Conclusions The potent induction of HIF-1α protein involved in its cytotoxicity, together with the suppression of HIF-1 transcriptional
In Vitro Anticancer Activity of Phlorofucofuroeckol A via Upregulation of Activating Transcription Factor 3 against Human Colorectal Cancer Cells

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Hyun Ji Eo

2016-03-01

Full Text Available Phlorofucofuroeckol A (PFF-A, one of the phlorotannins found in brown algae, has been reported to exert anti-cancer property. However, the molecular mechanism for the anti-cancer effect of PFF-A has not been known. Activating transcription factor 3 (ATF3 has been reported to be associated with apoptosis in colorectal cancer. The present study was performed to investigate the molecular mechanism by which PFF-A stimulates ATF3 expression and apoptosis in human colorectal cancer cells. PFF-A decreased cell viability through apoptosis of human colorectal cancer cells. PFF-A increased ATF3 expression through regulating transcriptional activity. The responsible cis-element for ATF3 transcriptional activation by PFF-A was cAMP response element binding protein (CREB, located between positions −147 and −85 of the ATF3 promoter. Inhibition of p38, c-Jun N-terminal kinases (JNK, glycogen synthase kinase (GSK 3β, and IκB kinase (IKK-α blocked PFF-A-mediated ATF3 expression. ATF3 knockdown by ATF3 siRNA attenuated the cleavage of poly (ADP-ribose polymerase (PARP by PFF-A, while ATF3 overexpression increased PFF-A-mediated cleaved PARP. These results suggest that PFF-A may exert anti-cancer property through inducing apoptosis via the ATF3-mediated pathway in human colorectal cancer cells.
The splicing regulator PTBP1 controls the activity of the transcription factor Pbx1 during neuronal differentiation.

Science.gov (United States)

Linares, Anthony J; Lin, Chia-Ho; Damianov, Andrey; Adams, Katrina L; Novitch, Bennett G; Black, Douglas L

2015-12-24

The RNA-binding proteins PTBP1 and PTBP2 control programs of alternative splicing during neuronal development. PTBP2 was found to maintain embryonic splicing patterns of many synaptic and cytoskeletal proteins during differentiation of neuronal progenitor cells (NPCs) into early neurons. However, the role of the earlier PTBP1 program in embryonic stem cells (ESCs) and NPCs was not clear. We show that PTBP1 controls a program of neuronal gene expression that includes the transcription factor Pbx1. We identify exons specifically regulated by PTBP1 and not PTBP2 as mouse ESCs differentiate into NPCs. We find that PTBP1 represses Pbx1 exon 7 and the expression of the neuronal Pbx1a isoform in ESCs. Using CRISPR-Cas9 to delete regulatory elements for exon 7, we induce Pbx1a expression in ESCs, finding that this activates transcription of neuronal genes. Thus, PTBP1 controls the activity of Pbx1 to suppress its neuronal transcriptional program prior to induction of NPC development.

Hepatitis C virus core protein regulates p300/CBP co-activation function. Possible role in the regulation of NF-AT1 transcriptional activity

International Nuclear Information System (INIS)

Gomez-Gonzalo, Marta; Benedicto, Ignacio; Carretero, Marta; Lara-Pezzi, Enrique; Maldonado-Rodriguez, Alejandra; Moreno-Otero, Ricardo; Lai, Michael M.C.; Lopez-Cabrera, Manuel

2004-01-01

Hepatitis C virus (HCV) core is a viral structural protein; it also participates in some cellular processes, including transcriptional regulation. However, the mechanisms of core-mediated transcriptional regulation remain poorly understood. Oncogenic virus proteins often target p300/CBP, a known co-activator of a wide variety of transcription factors, to regulate the expression of cellular and viral genes. Here we demonstrate, for the first time, that HCV core protein interacts with p300/CBP and enhances both its acetyl-transferase and transcriptional activities. In addition, we demonstrate that nuclear core protein activates the NH 2 -terminal transcription activation domain (TAD) of NF-AT1 in a p300/CBP-dependent manner. We propose a model in which core protein regulates the co-activation function of p300/CBP and activates NF-AT1, and probably other p300/CBP-regulated transcription factors, by a novel mechanism involving the regulation of the acetylation state of histones and/or components of the transcriptional machinery
A novel hemoglobin variant found on the α1 chain: Hb KSVGH (HBA1: p.Lys57_Gly58insSerHisGlySerAlaGlnValLys).

Science.gov (United States)

Wang, Mei-Chun; Tsai, Kuo-Wang; Chu, Chih-Hsun; Yu, Ming-Sun; Lam, Hing-Chung

2015-01-01

Glycosylated hemoglobin (Hb A1C) is a crucial indicator for the long-term control and the diagnosis of diabetes. However, the presence of hemoglobin (Hb) variants may affect the measured value of Hb A1C and result in an abnormal graph trend and inconsistency between the clinical blood sugar test and Hb A1C values. In this study, laboratory data of 41,267 patients with diabetes were collected. The Hb A1C levels and the graph results were examined. We identified 74 cases containing abnormal Hb A1C graph trends. The conducted blood cell counts and capillary Hb electrophoresis were used to analyze Hb variants. We also determined gene variation for the Hb variants by a sequence approach. Fifteen different types of Hb variants were identified in this study. Among these, we found a novel variant in which the α1 subunit of Hb showed an insertion of 24 nucleotides (nts) between the 56th and 57th residues. We named this novel variant Hb Kaohsiung Veterans General Hospital (Hb KSVGH) (HBA1: p.Lys57_Gly58insSerHisGlySerAlaGlnValLys).
Parathyroid hormone inhibition of Na{sup +}/H{sup +} exchanger 3 transcription: Intracellular signaling pathways and transcription factor expression

Energy Technology Data Exchange (ETDEWEB)

Neri, Elida Adalgisa; Bezerra, Camila Nogueira Alves, E-mail: camilab@icb.usp.br; Queiroz-Leite, Gabriella Duarte; Polidoro, Juliano Zequini; Rebouças, Nancy Amaral

2015-06-12

The main transport mechanism of reabsorption of sodium bicarbonate and fluid in the renal proximal tubules involves Na{sup +}/H{sup +} exchanger 3 (NHE3), which is acutely and chronically downregulated by parathyroid hormone (PTH). Although PTH is known to exert an inhibitory effect on NHE3 expression and transcription, the molecular mechanisms involved remain unclear. Here, we demonstrated that, in opossum kidney proximal tubule (OKP) cells, PTH-induced inhibition of Nhe3 gene promoter occurs even in the core promoter that controls expression of the reporter gene. We found that inhibition of the protein kinase A (PKA) and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways transformed PTH from an inhibitor of promoter activity into an activator of that same activity, as did point mutations in the EGR1, Sp1, and Sp3 binding consensus elements in the promoter. In nuclear extracts of PTH-treated OKP cells, we also observed increased expression of EGR1 mRNA and of some Sp3 isoforms. Electrophoretic mobility shift assay showed a supershift of the −61 to −42-bp probe with an anti-EGR1 antibody in PTH-treated cells, suggesting that EGR1 binding is relevant for the inhibitory activity of PTH. We conclude that PTH-induced inhibition of NHE3 transcription is related to higher EGR1 expression; to EGR1 binding to the proximal and core promoters; and to PKA and JAK/STAT pathway activation. This mechanism might be responsible, at least in part, for lower NHE3 expression and sodium reabsorption in renal proximal tubules in the presence of high PTH levels. - Highlights: • PTH regulation of Nhe3 promoter depends on EGR1 binding. • EGR1, PKA and JAK/STAT are involved in PTH inhibition of the Nhe3 promoter. • PTH alters expression of EGR1 and Sp3. • PTH inhibits the Nhe3 promoter by regulating PKA and JAK/STAT signaling.
Resveratrol stimulates c-Fos gene transcription via activation of ERK1/2 involving multiple genetic elements.

Science.gov (United States)

Thiel, Gerald; Rössler, Oliver G

2018-06-05

The polyphenol resveratrol is found in many plant and fruits and is a constituent of our diet. Resveratrol has been proposed to have chemopreventive and anti-inflammatory activities. On the cellular level, resveratrol activates stimulus-regulated transcription factors. To identify resveratrol-responsive elements within a natural gene promoter, the molecular pathway leading to c-Fos gene expression by resveratrol was dissected. The c-Fos gene encodes a basic region leucine zipper transcription factor and is a prototype of an immediate-early gene that is regulated by a wide range of signaling molecules. We analyzed chromatin-integrated c-Fos promoter-luciferase reporter genes where transcription factor binding sites were destroyed by point mutations or deletion mutagenesis. The results show that mutation of the binding sites for serum response factor (SRF), activator protein-1 (AP-1) and cAMP response element binding protein (CREB) significantly reduced reporter gene transcription following stimulation of the cells with resveratrol. Inactivation of the binding sites for signal transducer and activator of transcription (STAT) or ternary complex factors did not influence resveratrol-regulated c-Fos promoter activity. Thus, the c-Fos promoter contains three resveratrol-responsive elements, the cAMP response element (CRE), and the binding sites for SRF and AP-1. Moreover, we show that the transcriptional activation potential of the c-Fos protein is increased in resveratrol-stimulated cells, indicating that the biological activity of c-Fos is elevated by resveratrol stimulation. Pharmacological and genetic experiments revealed that the protein kinase ERK1/2 is the signal transducer that connects resveratrol treatment with the c-Fos gene. Copyright © 2018 Elsevier B.V. All rights reserved.
Ubiquitin ligase activity of TFIIH and the transcriptional response to DNA damage.

Science.gov (United States)

Takagi, Yuichiro; Masuda, Claudio A; Chang, Wei-Hau; Komori, Hirofumi; Wang, Dong; Hunter, Tony; Joazeiro, Claudio A P; Kornberg, Roger D

2005-04-15

Core transcription factor (TF) IIH purified from yeast possesses an E3 ubiquitin (Ub) ligase activity, which resides, at least in part, in a RING finger (RNF) domain of the Ssl1 subunit. Yeast strains mutated in the Ssl1 RNF domain are sensitive to ultraviolet (UV) light and to methyl methanesulfonate (MMS). This increased sensitivity to DNA-damaging agents does not reflect a deficiency in nucleotide excision repair. Rather, it correlates with reduced transcriptional induction of genes involved in DNA repair, suggesting that the E3 Ub ligase activity of TFIIH mediates the transcriptional response to DNA damage.
Allele-specific MMP-3 transcription under in vivo conditions

Energy Technology Data Exchange (ETDEWEB)

Chaoyong, Zhu [Atherosclerosis Research Unit, King Gustav V Research Institute, Department of Medicine, Karolinska Institute, Stockholm (Sweden); Odeberg, Jacob [Atherosclerosis Research Unit, King Gustav V Research Institute, Department of Medicine, Karolinska Institute, Stockholm (Sweden); Department of Biotechnology, AlbaNova University Center, Royal Institute of Technology, Stockholm (Sweden); Hamsten, Anders [Atherosclerosis Research Unit, King Gustav V Research Institute, Department of Medicine, Karolinska Institute, Stockholm (Sweden); Eriksson, Per [Atherosclerosis Research Unit, King Gustav V Research Institute, Department of Medicine, Karolinska Institute, Stockholm (Sweden)

2006-09-29

A common matrix metalloproteinases-3 (MMP-3) -1612 5A/6A promoter polymorphism is associated with risk for cardiovascular disease, rheumatoid arthritis, and other diseases. Here we used the haplotype chromatin immunoprecipitation method to study allele-specific MMP-3 expression under in vivo conditions in heterozygous THP-1 cells. Pyrosequencing was used to analyse the ratio of 5A-allele to 6A-allele after chromatin immunoprecipitation using an antibody against phosphorylated active RNA polymerase II. There was no allele-specific difference in transcriptional activity during basal conditions, i.e., in unstimulated monocytic THP-1 cells. However, after stimulation of MMP-3 expression by monocyte differentiation or incubation with IL-1{beta}, the haplotype containing the 5A-allele was associated with higher transcriptional activity compared with the 6A-containing haplotype. Electromobility shift assay demonstrated increased binding of nuclear proteins to the 5A-allele after monocyte differentiation. In conclusion, the common MMP-3 5A/6A promoter polymorphism appears to be functional only during specific environmental conditions involving inflammation.
Therapeutic doses of irradiation activate viral transcription and induce apoptosis in HIV-1 infected cells

International Nuclear Information System (INIS)

Iordanskiy, Sergey; Van Duyne, Rachel; Sampey, Gavin C; Woodson, Caitlin M; Fry, Kelsi; Saifuddin, Mohammed; Guo, Jia; Wu, Yuntao; Romerio, Fabio; Kashanchi, Fatah

2015-01-01

The highly active antiretroviral therapy reduces HIV-1 RNA in plasma to undetectable levels. However, the virus continues to persist in the long-lived resting CD4"+ T cells, macrophages and astrocytes which form a viral reservoir in infected individuals. Reactivation of viral transcription is critical since the host immune response in combination with antiretroviral therapy may eradicate the virus. Using the chronically HIV-1 infected T lymphoblastoid and monocytic cell lines, primary quiescent CD4"+ T cells and humanized mice infected with dual-tropic HIV-1 89.6, we examined the effect of various X-ray irradiation (IR) doses (used for HIV-related lymphoma treatment and lower doses) on HIV-1 transcription and viability of infected cells. Treatment of both T cells and monocytes with IR, a well-defined stress signal, led to increase of HIV-1 transcription, as evidenced by the presence of RNA polymerase II and reduction of HDAC1 and methyl transferase SUV39H1 on the HIV-1 promoter. This correlated with the increased GFP signal and elevated level of intracellular HIV-1 RNA in the IR-treated quiescent CD4"+ T cells infected with GFP-encoding HIV-1. Exposition of latently HIV-1infected monocytes treated with PKC agonist bryostatin 1 to IR enhanced transcription activation effect of this latency-reversing agent. Increased HIV-1 replication after IR correlated with higher cell death: the level of phosphorylated Ser46 in p53, responsible for apoptosis induction, was markedly higher in the HIV-1 infected cells following IR treatment. Exposure of HIV-1 infected humanized mice with undetectable viral RNA level to IR resulted in a significant increase of HIV-1 RNA in plasma, lung and brain tissues. Collectively, these data point to the use of low to moderate dose of IR alone or in combination with HIV-1 transcription activators as a potential application for the “Shock and Kill” strategy for latently HIV-1 infected cells. - Highlights: • X-ray irradiation (IR) increases
Therapeutic doses of irradiation activate viral transcription and induce apoptosis in HIV-1 infected cells

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Iordanskiy, Sergey [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Van Duyne, Rachel [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702 (United States); Sampey, Gavin C; Woodson, Caitlin M; Fry, Kelsi; Saifuddin, Mohammed; Guo, Jia; Wu, Yuntao [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States); Romerio, Fabio [Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201 (United States); Kashanchi, Fatah, E-mail: fkashanc@gmu.edu [School of Systems Biology, Laboratory of Molecular Virology, George Mason University, Manassas, VA 20110 (United States)

2015-11-15

The highly active antiretroviral therapy reduces HIV-1 RNA in plasma to undetectable levels. However, the virus continues to persist in the long-lived resting CD4{sup +} T cells, macrophages and astrocytes which form a viral reservoir in infected individuals. Reactivation of viral transcription is critical since the host immune response in combination with antiretroviral therapy may eradicate the virus. Using the chronically HIV-1 infected T lymphoblastoid and monocytic cell lines, primary quiescent CD4{sup +} T cells and humanized mice infected with dual-tropic HIV-1 89.6, we examined the effect of various X-ray irradiation (IR) doses (used for HIV-related lymphoma treatment and lower doses) on HIV-1 transcription and viability of infected cells. Treatment of both T cells and monocytes with IR, a well-defined stress signal, led to increase of HIV-1 transcription, as evidenced by the presence of RNA polymerase II and reduction of HDAC1 and methyl transferase SUV39H1 on the HIV-1 promoter. This correlated with the increased GFP signal and elevated level of intracellular HIV-1 RNA in the IR-treated quiescent CD4{sup +} T cells infected with GFP-encoding HIV-1. Exposition of latently HIV-1infected monocytes treated with PKC agonist bryostatin 1 to IR enhanced transcription activation effect of this latency-reversing agent. Increased HIV-1 replication after IR correlated with higher cell death: the level of phosphorylated Ser46 in p53, responsible for apoptosis induction, was markedly higher in the HIV-1 infected cells following IR treatment. Exposure of HIV-1 infected humanized mice with undetectable viral RNA level to IR resulted in a significant increase of HIV-1 RNA in plasma, lung and brain tissues. Collectively, these data point to the use of low to moderate dose of IR alone or in combination with HIV-1 transcription activators as a potential application for the “Shock and Kill” strategy for latently HIV-1 infected cells. - Highlights: • X-ray irradiation
Activating Transcription Factor 3 Regulates Immune and Metabolic Homeostasis

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Rynes, Jan; Donohoe, Colin D.; Frommolt, Peter; Brodesser, Susanne; Jindra, Marek

2012-01-01

Integration of metabolic and immune responses during animal development ensures energy balance, permitting both growth and defense. Disturbed homeostasis causes organ failure, growth retardation, and metabolic disorders. Here, we show that the Drosophila melanogaster activating transcription factor 3 (Atf3) safeguards metabolic and immune system homeostasis. Loss of Atf3 results in chronic inflammation and starvation responses mounted primarily by the larval gut epithelium, while the fat body suffers lipid overload, causing energy imbalance and death. Hyperactive proinflammatory and stress signaling through NF-κB/Relish, Jun N-terminal kinase, and FOXO in atf3 mutants deregulates genes important for immune defense, digestion, and lipid metabolism. Reducing the dose of either FOXO or Relish normalizes both lipid metabolism and gene expression in atf3 mutants. The function of Atf3 is conserved, as human ATF3 averts some of the Drosophila mutant phenotypes, improving their survival. The single Drosophila Atf3 may incorporate the diversified roles of two related mammalian proteins. PMID:22851689
Activating transcription factor 3 regulates immune and metabolic homeostasis.

Science.gov (United States)

Rynes, Jan; Donohoe, Colin D; Frommolt, Peter; Brodesser, Susanne; Jindra, Marek; Uhlirova, Mirka

2012-10-01

Integration of metabolic and immune responses during animal development ensures energy balance, permitting both growth and defense. Disturbed homeostasis causes organ failure, growth retardation, and metabolic disorders. Here, we show that the Drosophila melanogaster activating transcription factor 3 (Atf3) safeguards metabolic and immune system homeostasis. Loss of Atf3 results in chronic inflammation and starvation responses mounted primarily by the larval gut epithelium, while the fat body suffers lipid overload, causing energy imbalance and death. Hyperactive proinflammatory and stress signaling through NF-κB/Relish, Jun N-terminal kinase, and FOXO in atf3 mutants deregulates genes important for immune defense, digestion, and lipid metabolism. Reducing the dose of either FOXO or Relish normalizes both lipid metabolism and gene expression in atf3 mutants. The function of Atf3 is conserved, as human ATF3 averts some of the Drosophila mutant phenotypes, improving their survival. The single Drosophila Atf3 may incorporate the diversified roles of two related mammalian proteins.
Acetylation Increases EWS-FLI1 DNA Binding and Transcriptional Activity

International Nuclear Information System (INIS)

Schlottmann, Silke; Erkizan, Hayriye V.; Barber-Rotenberg, Julie S.; Knights, Chad; Cheema, Amrita; Üren, Aykut; Avantaggiati, Maria L.; Toretsky, Jeffrey A.

2012-01-01

Ewing Sarcoma (ES) is associated with a balanced chromosomal translocation that in most cases leads to the expression of the oncogenic fusion protein and transcription factor EWS-FLI1. EWS-FLI1 has been shown to be crucial for ES cell survival and tumor growth. However, its regulation is still enigmatic. To date, no functionally significant post-translational modifications of EWS-FLI1 have been shown. Since ES are sensitive to histone deacetylase inhibitors (HDI), and these inhibitors are advancing in clinical trials, we sought to identify if EWS-FLI1 is directly acetylated. We convincingly show acetylation of the C-terminal FLI1 (FLI1-CTD) domain, which is the DNA binding domain of EWS-FLI1. In vitro acetylation studies showed that acetylated FLI1-CTD has higher DNA binding activity than the non-acetylated protein. Over-expression of PCAF or treatment with HDI increased the transcriptional activity of EWS-FLI1, when co-expressed in Cos7 cells. However, our data that evaluates the acetylation of full-length EWS-FLI1 in ES cells remains unclear, despite creating acetylation specific antibodies to four potential acetylation sites. We conclude that EWS-FLI1 may either gain access to chromatin as a result of histone acetylation or undergo regulation by direct acetylation. These data should be considered when patients are treated with HDAC inhibitors. Further investigation of this phenomenon will reveal if this potential acetylation has an impact on tumor response.
Foxf genes integrate tbx5 and hedgehog pathways in the second heart field for cardiac septation.

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Andrew D Hoffmann

2014-10-01

Full Text Available The Second Heart Field (SHF has been implicated in several forms of congenital heart disease (CHD, including atrioventricular septal defects (AVSDs. Identifying the SHF gene regulatory networks required for atrioventricular septation is therefore an essential goal for understanding the molecular basis of AVSDs. We defined a SHF Hedgehog-dependent gene regulatory network using whole genome transcriptional profiling and GLI-chromatin interaction studies. The Forkhead box transcription factors Foxf1a and Foxf2 were identified as SHF Hedgehog targets. Compound haploinsufficiency for Foxf1a and Foxf2 caused atrioventricular septal defects, demonstrating the biological relevance of this regulatory network. We identified a Foxf1a cis-regulatory element that bound the Hedgehog transcriptional regulators GLI1 and GLI3 and the T-box transcription factor TBX5 in vivo. GLI1 and TBX5 synergistically activated transcription from this cis-regulatory element in vitro. This enhancer drove reproducible expression in vivo in the posterior SHF, the only region where Gli1 and Tbx5 expression overlaps. Our findings implicate Foxf genes in atrioventricular septation, describe the molecular underpinnings of the genetic interaction between Hedgehog signaling and Tbx5, and establish a molecular model for the selection of the SHF gene regulatory network for cardiac septation.
Human cytomegalovirus (HCMV) induces human endogenous retrovirus (HERV) transcription.

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Assinger, Alice; Yaiw, Koon-Chu; Göttesdorfer, Ingmar; Leib-Mösch, Christine; Söderberg-Nauclér, Cecilia

2013-11-12

Emerging evidence suggests that human cytomegalovirus (HCMV) is highly prevalent in tumours of different origin. This virus is implied to have oncogenic and oncomodulatory functions, through its ability to control host gene expression. Human endogenous retroviruses (HERV) are also frequently active in tumours of different origin, and are supposed to contribute as cofactors to cancer development. Due to the high prevalence of HCMV in several different tumours, and its ability to control host cell gene expression, we sought to define whether HCMV may affect HERV transcription. Infection of 3 established cancer cell lines, 2 primary glioblastoma cells, endothelial cells from 3 donors and monocytes from 4 donors with HCMV (strains VR 1814 or TB40/F) induced reverse transcriptase (RT) activity in all cells tested, but the response varied between donors. Both, gammaretrovirus-related class I elements HERV-T, HERV-W, HERV-F and ERV-9, and betaretrovirus-related class II elements HML-2 - 4 and HML-7 - 8, as well as spuma-virus related class III elements of the HERV-L group were up-regulated in response to HCMV infection in GliNS1 cells. Up-regulation of HERV activity was more pronounced in cells harbouring active HCMV infection, but was also induced by UV-inactivated virus. The effect was only slightly affected by ganciclovir treatment and was not controlled by the IE72 or IE86 HCMV genes. Within this brief report we show that HCMV infection induces HERV transcriptional activity in different cell types.
Global effects of the CSR-1 RNA interference pathway on transcriptional landscape

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Cecere, Germano; Hoersch, Sebastian; O’Keeffe, Sean; Sachidanandam, Ravi; Grishok, Alla

2014-01-01

Argonaute proteins and their small RNA co-factors short interfering RNAs (siRNAs) are known to inhibit gene expression at the transcriptional and post-transcriptional levels. In Caenorhabditis elegans, the Argonaute CSR-1 binds thousands of endogenous siRNAs (endo-siRNAs) antisense to germline transcripts and associates with chromatin in a siRNA-dependent manner. However, its role in gene expression regulation remains controversial. Here, we used a genome-wide profiling of nascent RNA transcripts to demonstrate that the CSR-1 RNAi pathway promotes sense-oriented Pol II transcription. Moreover, a loss of CSR-1 function resulted in global increase in antisense transcription and ectopic transcription of silent chromatin domains, which led to reduced chromatin incorporation of centromere-specific histone H3. Based on these findings, we propose that the CSR-1 pathway has a role in maintaining the directionality of active transcription thereby propagating the distinction between transcriptionally active and silent genomic regions. PMID:24681887
Regulation of cAMP Responsive Element Binding Protein 3-Like 1 (Creb3l1 Expression by Orphan Nuclear Receptor Nr4a1

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Michael P. Greenwood

2017-12-01

Full Text Available Cyclic AMP (cAMP inducible transcription factor cAMP responsive element binding protein 3 like 1 (Creb3l1 is strongly activated in the hypothalamus in response to hyperosmotic cues such as dehydration (DH. We have recently shown that Creb3l1 expression is upregulated by cAMP pathways in vitro, however the exact mechanisms are not known. Here we show that increasing Creb3l1 transcription by raising cAMP levels in mouse pituitary AtT20 cells automatically initiates cleavage of Creb3l1, leading to a greater abundance of the transcriptionally active N-terminal portion. Inhibiting protein synthesis indicated that de novo protein synthesis of an intermediary transcription factor was required for Creb3l1 induction. Strategic mining of our microarray data from dehydrated rodent hypothalamus revealed four candidates, reduced to two by analysis of acute hyperosmotic-induced transcriptional activation profiles in the hypothalamus, and one, orphan nuclear receptor Nr4a1, by direct shRNA mediated silencing in AtT20 cells. We show that activation of Creb3l1 transcription by Nr4a1 involves interaction with a single NBRE site in the promoter region. The ability to activate Creb3l1 transcription by this pathway in vitro is dictated by the level of methylation of a CpG island within the proximal promoter/5′UTR of this gene. We thus identify a novel cAMP-Nr4a1-Creb3l1 transcriptional pathway in AtT20 cells and also, our evidence would suggest, in the hypothalamus.
Cdk1 activity acts as a quantitative platform for coordinating cell cycle progression with periodic transcription

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Banyai, Gabor; Baïdi, Feriel; Coudreuse, Damien; Szilagyi, Zsolt

2016-01-01

Cell proliferation is regulated by cyclin-dependent kinases (Cdks) and requires the periodic expression of particular gene clusters in different cell cycle phases. However, the interplay between the networks that generate these transcriptional oscillations and the core cell cycle machinery remains largely unexplored. In this work, we use a synthetic regulable Cdk1 module to demonstrate that periodic expression is governed by quantitative changes in Cdk1 activity, with different clusters directly responding to specific activity levels. We further establish that cell cycle events neither participate in nor interfere with the Cdk1-driven transcriptional program, provided that cells are exposed to the appropriate Cdk1 activities. These findings contrast with current models that propose self-sustained and Cdk1-independent transcriptional oscillations. Our work therefore supports a model in which Cdk1 activity serves as a quantitative platform for coordinating cell cycle transitions with the expression of critical genes to bring about proper cell cycle progression. PMID:27045731
Overactivation of Hedgehog Signaling Alters Development of the Ovarian Vasculature in Mice1

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Ren, Yi; Cowan, Robert G.; Migone, Fernando F.; Quirk, Susan M.

2012-01-01

ABSTRACT The hedgehog (HH) signaling pathway is critical for ovarian function in Drosophila, but its role in the mammalian ovary has not been defined. Previously, expression of a dominant active allele of the HH signal transducer protein smoothened (SMO) in Amhr2cre/+SmoM2 mice caused anovulation in association with a lack of smooth muscle in the theca of developing follicles. The current study examined events during the first 2 wk of life in Amhr2cre/+SmoM2 mice to gain insight into the cause of anovulation. Expression of transcriptional targets of HH signaling, Gli1, Ptch1, and Hhip, which are used as measures of pathway activity, were elevated during the first several days of life in Amhr2cre/+SmoM2 mice compared to controls but were similar to controls in older mice. Microarray analysis showed that genes with increased expression in 2-day-old mutants compared to controls were enriched for the processes of vascular and tube development and steroidogenesis. The density of platelet endothelial cell adhesion molecule (PECAM)-labeled endothelial tubes was increased in the cortex of newborn ovaries of mutant mice. Costaining of preovulatory follicles for PECAM and smooth muscle actin showed that muscle-type vascular support cells are deficient in theca of mutant mice. Expression of genes for steroidogenic enzymes that are normally expressed in the fetal adrenal gland were elevated in newborn ovaries of mutant mice. In summary, overactivation of HH signaling during early life alters gene expression and vascular development and this is associated with the lifelong development of anovulatory follicles in which the thecal vasculature fails to mature appropriately. PMID:22402963
SIRT3 restricts HBV transcription and replication via epigenetic regulation of cccDNA involving SUV39H1 and SETD1A histone methyltransferases.

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Ren, Ji-Hua; Hu, Jie-Li; Cheng, Sheng-Tao; Yu, Hai-Bo; Wong, Vincent Kam Wai; Law, Betty Yuen Kwan; Yang, Yong-Feng; Huang, Ying; Liu, Yi; Chen, Wei-Xian; Cai, Xue-Fei; Tang, Hua; Hu, Yuan; Zhang, Wen-Lu; Liu, Xiang; Long, Quan-Xin; Zhou, Li; Tao, Na-Na; Zhou, Hong-Zhong; Yang, Qiu-Xia; Ren, Fang; He, Lin; Gong, Rui; Huang, Ai-Long; Chen, Juan

2018-04-06

Hepatitis B virus (HBV) infection remains a major health problem worldwide. Maintenance of the covalently closed circular DNA (cccDNA) which serves as a template for HBV RNA transcription is responsible for the failure of eradicating chronic HBV during current antiviral therapy. cccDNA is assembled with cellular histone proteins into chromatin, but little is known about the regulation of HBV chromatin by histone posttranslational modifications. In this study, we identified SIRT3 as a host factor restricting HBV transcription and replication by screening seven members of Sirtuin family which is the class III histone deacetylase. Ectopic SIRT3 expression significantly reduced total HBV RNAs, 3.5-kb RNA as well as replicative intermediate DNA in HBV-infected HepG2-NTCP cells and PHH. In contrast, gene silencing of SIRT3 promoted HBV transcription and replication. Mechanistic study found nuclear SIRT3 was recruited to the HBV cccDNA, where it deacetylated histone 3 lysine 9 (H3K9). Importantly, occupancy of SIRT3 onto cccDNA could increase the recruitment of histone methyltransferase SUV39H1 to cccDNA and decrease recruitment of SETD1A, leading to a marked increase of H3K9me3 and a decrease of H3K4me3 on cccDNA. Moreover, SIRT3-mediated HBV cccDNA transcriptional repression involved decreased binding of host RNA polymerase II and transcription factor YY1 to cccDNA. Finally, viral protein HBx could relieve SIRT3-mediated cccDNA transcriptional repression by inhibiting both SIRT3 expression and its recruitment to cccDNA. SIRT3 is a novel host factor epigenetically restricting HBV cccDNA transcription by acting cooperatively with histone methyltransferase. These data provided a rational for the use of SIRT3 activators in the prevention or treatment of HBV infection. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.
Exercise induces transient transcriptional activation of the PGC-1a gene in human skeletal muscle

DEFF Research Database (Denmark)

Pilegaard, Henriette; Saltin, Bengt; Neufer, P. Darrell

2003-01-01

Endurance exercise training induces mitochondrial biogenesis in skeletal muscle. The peroxisome proliferator activated receptor co-activator 1a (PGC-1a) has recently been identified as a nuclear factor critical for coordinating the activation of genes required for mitochondrial biogenesis in cell...... culture and rodent skeletal muscle. To determine whether PGC-1a transcription is regulated by acute exercise and exercise training in human skeletal muscle, seven male subjects performed 4 weeks of one-legged knee extensor exercise training. At the end of training, subjects completed 3 h of two......-legged knee extensor exercise. Biopsies were obtained from the vastus lateralis muscle of both the untrained and trained legs before exercise and after 0, 2, 6 and 24 h of recovery. Time to exhaustion (2 min maximum resistance), as well as hexokinase II (HKII), citrate synthase and 3-hydroxyacyl...
Fungal mediator tail subunits contain classical transcriptional activation domains.

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Liu, Zhongle; Myers, Lawrence C

2015-04-01

Classical activation domains within DNA-bound eukaryotic transcription factors make weak interactions with coactivator complexes, such as Mediator, to stimulate transcription. How these interactions stimulate transcription, however, is unknown. The activation of reporter genes by artificial fusion of Mediator subunits to DNA binding domains that bind to their promoters has been cited as evidence that the primary role of activators is simply to recruit Mediator. We have identified potent classical transcriptional activation domains in the C termini of several tail module subunits of Saccharomyces cerevisiae, Candida albicans, and Candida dubliniensis Mediator, while their N-terminal domains are necessary and sufficient for their incorporation into Mediator but do not possess the ability to activate transcription when fused to a DNA binding domain. This suggests that Mediator fusion proteins actually are functioning in a manner similar to that of a classical DNA-bound activator rather than just recruiting Mediator. Our finding that deletion of the activation domains of S. cerevisiae Med2 and Med3, as well as C. dubliniensis Tlo1 (a Med2 ortholog), impairs the induction of certain genes shows these domains function at native promoters. Activation domains within coactivators are likely an important feature of these complexes and one that may have been uniquely leveraged by a common fungal pathogen. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Global effects of the CSR-1 RNA interference pathway on the transcriptional landscape.

Science.gov (United States)

Cecere, Germano; Hoersch, Sebastian; O'Keeffe, Sean; Sachidanandam, Ravi; Grishok, Alla

2014-04-01

Argonaute proteins and their small RNA cofactors short interfering RNAs are known to inhibit gene expression at the transcriptional and post-transcriptional levels. In Caenorhabditis elegans, the Argonaute CSR-1 binds thousands of endogenous siRNAs (endo-siRNAs) that are antisense to germline transcripts. However, its role in gene expression regulation remains controversial. Here we used genome-wide profiling of nascent RNA transcripts and found that the CSR-1 RNA interference pathway promoted sense-oriented RNA polymerase II transcription. Moreover, a loss of CSR-1 function resulted in global increase in antisense transcription and ectopic transcription of silent chromatin domains, which led to reduced chromatin incorporation of centromere-specific histone H3. On the basis of these findings, we propose that the CSR-1 pathway helps maintain the directionality of active transcription, thereby propagating the distinction between transcriptionally active and silent genomic regions.
Stimulation of ribosomal RNA gene promoter by transcription factor Sp1 involves active DNA demethylation by Gadd45-NER pathway.

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Rajput, Pallavi; Pandey, Vijaya; Kumar, Vijay

2016-08-01

The well-studied Pol II transcription factor Sp1 has not been investigated for its regulatory role in rDNA transcription. Here, we show that Sp1 bound to specific sites on rDNA and localized into the nucleoli during the G1 phase of cell cycle to activate rDNA transcription. It facilitated the recruitment of Pol I pre-initiation complex and impeded the binding of nucleolar remodeling complex (NoRC) to rDNA resulting in the formation of euchromatin active state. More importantly, Sp1 also orchestrated the site-specific binding of Gadd45a-nucleotide excision repair (NER) complex resulting in active demethylation and transcriptional activation of rDNA. Interestingly, knockdown of Sp1 impaired rDNA transcription due to reduced engagement of the Gadd45a-NER complex and hypermethylation of rDNA. Thus, the present study unveils a novel role of Sp1 in rDNA transcription involving promoter demethylation. Copyright © 2016 Elsevier B.V. All rights reserved.
Evaluation of the oxidative stress modulation in Drosophila melanogaster strains deficient in endogenous antioxidants and with chronic exposure to casiopeina Cas II-gly and gamma radiation; Evaluacion de la modulacion del estres oxidante en cepas de Drosophila melanogaster deficientes en antioxidantes endogenos y con exposicion cronica a casiopeina CII-gly y radiacion gamma

Energy Technology Data Exchange (ETDEWEB)

Jimenez V, E. R.

2013-07-01

The casiopeinas are a family of coordination compounds with copper metallic center that have shown to have antineoplastic activity. The experimental evidences suggest that its action mechanism is through the generation of free radicals. The casiopeina (Cas II-gly) is believed to causes oxidative damage in the mitochondria, leading to the cellular death. The present study has the purpose to evaluate the antioxidant potential of the tetrapyrroles: cupro-sodica chlorophyllin (CSC), protoporphyrin-Ix (Pp-Ix) and the bilirubin (Bili) against the oxidant action of the Cas II-gly. The present study will also contribute in the characterization of the biological activity of the Cas II-gly. For this purpose is quantifies the effect of these compounds in the enzymes activity, superoxide dismutase (Sod) and catalase (Cat) in wild Drosophila melanogaster strains Canton-S and in the deficient in Sod and Cat. Two protocols were used, in the first male of 1-24 h of age were pre-treated with 0, 0.01, 0.1 and 1 m M of Cas II-gly and later on they were treated with radiation (15 Gy), and the second 69 m M of CSC, Pp-Ix or Bili, during 8 days and later they were treated with 0.1 m M of Cas II-gly during 24 h. The enzymatic activity was measured with the detection packages of enzymes Sod and Cat of Sigma. It was found that none of the three pigments increment the Sod activity but, if they diminished that of Cat (p≤0.007). The three concentrations of Cas II-gly did not increase the Sod activity significantly, only the concentration of 0.1 m M diminishes in 5.6 U the Cat activity (p <0.03) the same as the treatment with 15 Gy of gamma rays (8 U, p <0.004). The Cas II-gly combination 0.1 m M with the pigments does not modify the Sod and Cat activity. These results suggest that the proven pigments act as antioxidants, avoiding the induction of exogenous antioxidants caused by the gamma rays or the Cas II-gly. (Author)
Replicative Stress Induces Intragenic Transcription of the ASE1 Gene that Negatively Regulates Ase1 Activity

OpenAIRE

McKnight, Kelly; Liu, Hong; Wang, Yanchang

2014-01-01

Intragenic transcripts initiate within the coding region of a gene, thereby producing shorter mRNAs and proteins. Although intragenic transcripts are widely expressed [1], their role in the functional regulation of genes remains largely unknown. In budding yeast, DNA replication stress activates the S-phase checkpoint that stabilizes replication forks and arrests cells in S-phase with a short spindle [2-4]. When yeast cells were treated with hydroxyurea (HU) to block DNA synthesis and induce ...
Signal transducer and activator of transcription 3 activation is associated with bladder cancer cell growth and survival

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Hsieh Fu-Chuan

2008-10-01

Full Text Available Abstract Background Constitutive activation of signal transducer and activator of transcription 3 (Stat3 signaling pathway plays an important role in several human cancers. Activation of Stat3 is dependent on the phosphorylation at the tyrosine residue 705 by upstream kinases and subsequent nuclear translocation after dimerization. It remains unclear whether oncogenic Stat3 signaling pathway is involved in the oncogenesis of bladder cancer. Results We found that elevated Stat3 phosphorylation in 19 of 100 (19% bladder cancer tissues as well as bladder cancer cell lines, WH, UMUC-3 and 253J. To explore whether Stat3 activation is associated with cell growth and survival of bladder cancer, we targeted the Stat3 signaling pathway in bladder cancer cells using an adenovirus-mediated dominant-negative Stat3 (Y705F and a small molecule compound, STA-21. Both prohibited cell growth and induction of apoptosis in these bladder cancer cell lines but not in normal bladder smooth muscle cell (BdSMC. The survival inhibition might be mediated through apoptotic caspase 3, 8 and 9 pathways. Moreover, down-regulation of anti-apoptotic genes (Bcl-2, Bcl-xL and survivin and a cell cycle regulating gene (cyclin D1 was associated with the cell growth inhibition and apoptosis. Conclusion These results indicated that activation of Stat3 is crucial for bladder cancer cell growth and survival. Therefore, interference of Stat3 signaling pathway emerges as a potential therapeutic approach for bladder cancer.
First Exon Length Controls Active Chromatin Signatures and Transcription

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Nicole I. Bieberstein

2012-07-01

Full Text Available Here, we explore the role of splicing in transcription, employing both genome-wide analysis of human ChIP-seq data and experimental manipulation of exon-intron organization in transgenic cell lines. We show that the activating histone modifications H3K4me3 and H3K9ac map specifically to first exon-intron boundaries. This is surprising, because these marks help recruit general transcription factors (GTFs to promoters. In genes with long first exons, promoter-proximal levels of H3K4me3 and H3K9ac are greatly reduced; consequently, GTFs and RNA polymerase II are low at transcription start sites (TSSs and exhibit a second, promoter-distal peak from which transcription also initiates. In contrast, short first exons lead to increased H3K4me3 and H3K9ac at promoters, higher expression levels, accuracy in TSS usage, and a lower frequency of antisense transcription. Therefore, first exon length is predictive for gene activity. Finally, splicing inhibition and intron deletion reduce H3K4me3 levels and transcriptional output. Thus, gene architecture and splicing determines transcription quantity and quality as well as chromatin signatures.
Physicochemical Properties of Glycine-Based Ionic Liquid [QuatGly-OEt][EtOSO3] (2-Ethoxy-1-ethyl-1,1-dimethyl-2-oxoethanaminium ethyl sulfate and Its Binary Mixtures with Poly(ethylene glycol (Mw = 200 at Various Temperatures

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Chung-Wen Kuo

2011-12-01

Full Text Available This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL [QuatGly-OEt][EtOSO3] by NMR, elementary analysis and water content. Thermophysical properties such as density, ρ, viscosity, η, refractive index, n, and conductivity, κ, for the binary mixture of [QuatGly-OEt][EtOSO3] with poly(ethylene glycol (PEG [Mw = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO3] and its binary mixture can be described by an empirical polynomial equation and by the Vogel-Tammann-Fucher (VTF equation, respectively. The thermal expansion coefficient of the ILs is ascertained using the experimental density results, and the excess volume expansivity is evaluated. The negative values of excess molar volume for the mixture indicate the ion-dipole interactions and packing between IL and PEG oligomer. The results of binary excess property (VmE and deviations (Δη, ∆xn, ∆Фn, ∆xR, and ∆ФR are discussed in terms of molecular interactions and molecular structures in the binary mixture.
Physicochemical Properties of Glycine-Based Ionic Liquid [QuatGly-OEt][EtOSO3] (2-Ethoxy-1-ethyl-1,1-dimethyl-2-oxoethanaminium ethyl sulfate) and Its Binary Mixtures with Poly(ethylene glycol) (Mw = 200) at Various Temperatures

Science.gov (United States)

Wu, Tzi-Yi; Chen, Bor-Kuan; Hao, Lin; Lin, Yuan-Chung; Wang, H. Paul; Kuo, Chung-Wen; Sun, I-Wen

2011-01-01

This work includes specific basic characterization of synthesized glycine-based Ionic Liquid (IL) [QuatGly-OEt][EtOSO3] by NMR, elementary analysis and water content. Thermophysical properties such as density, ρ, viscosity, η, refractive index, n, and conductivity, κ, for the binary mixture of [QuatGly-OEt][EtOSO3] with poly(ethylene glycol) (PEG) [Mw = 200] are measured over the whole composition range. The temperature dependence of density and dynamic viscosity for neat [QuatGly-OEt][EtOSO3] and its binary mixture can be described by an empirical polynomial equation and by the Vogel-Tammann-Fucher (VTF) equation, respectively. The thermal expansion coefficient of the ILs is ascertained using the experimental density results, and the excess volume expansivity is evaluated. The negative values of excess molar volume for the mixture indicate the ion-dipole interactions and packing between IL and PEG oligomer. The results of binary excess property (VmE ) and deviations (Δη, Δxn, ΔΨn, ΔxR, and ΔΨR) are discussed in terms of molecular interactions and molecular structures in the binary mixture. PMID:22272102
CMYB1 Encoding a MYB Transcriptional Activator Is Involved in Abiotic Stress and Circadian Rhythm in Rice

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Min Duan

2014-01-01

Full Text Available Through analysis of cold-induced transcriptome, a novel gene encoding a putative MYB transcription factor was isolated and designated Cold induced MYB 1 (CMYB1. Tissue-specific gene expression analysis revealed that CMYB1 was highly expressed in rice stems and nodes. qRT-PCR assay indicated that CMYB1 was dramatically induced by cold stress (>100-folds and induced by exogenous ABA and osmotic stress. Interestingly, CMYB1 showed rhythmic expression profile in rice leaves at different developmental stages. Subcellular localization assay suggested that CMYB1-GFP (green fluorescent protein fusion protein was localized in the nuclei. Moreover, CMYB1 exhibited the transcriptional activation activity when transiently expressed in rice protoplast cells. Taken together, CMYB1 probably functions as a transcriptional activator in mediating stress and rhythm responsive gene expression in rice.
Anti-arrhythmic peptide N-3-(4-hydroxyphenyl)propionyl Pro-Hyp-Gly-Ala-Gly-OH reduces dispersion of action potential duration during ischemia/reperfusion in rabbit hearts

DEFF Research Database (Denmark)

Kjølbye, Anne Louise; Petersen, Jørgen Søberg; Holstein-Rathlou, N.-H.

2002-01-01

During ischemia, cardiac gap junctions close and neighboring cells uncouple. This leads to slow conduction, increased dispersion of APD90 (duration from action potential beginning to 90% of repolarization), nonuniform anisotropy, and unidirectional conduction block, all of which favor the induction...... of reentry arrhythmias. It has been suggested that anti-arrhythmic peptides increase gap junction conductance during states of reduced coupling. The aim of this study was to test the effect of the anti-arrhythmic peptide N-3-(4-hydroxyphenyl)propionyl Pro-Hyp-Gly-Ala-Gly-OH (HP-5) (10(-10) ) on dispersion...... of epicardial APD90 during both normokalemic and hypokalemic ischemia/reperfusion in isolated perfused rabbit hearts. HP-5 did not affect average APD90, heart rate, left ventricular contractility (LVP dP/dtmax), or mean coronary flow. HP-5 significantly reduced the epicardial APD dispersion during hypokalemic...
Exploring cellular memory molecules marking competent and active transcriptions

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Liu De-Pei

2007-05-01

Full Text Available Abstract Background Development in higher eukaryotes involves programmed gene expression. Cell type-specific gene expression is established during this process and is inherited in succeeding cell cycles. Higher eukaryotes have evolved elegant mechanisms by which committed gene-expression states are transmitted through numerous cell divisions. Previous studies have shown that both DNase I-sensitive sites and the basal transcription factor TFIID remain on silenced mitotic chromosomes, suggesting that certain trans-factors might act as bookmarks, maintaining the information and transmitting it to the next generation. Results We used the mouse globin gene clusters as a model system to examine the retention of active information on M-phase chromosomes and its contribution to the persistence of transcriptional competence of these gene clusters in murine erythroleukemia cells. In cells arrested in mitosis, the erythroid-specific activator NF-E2p45 remained associated with its binding sites on the globin gene loci, while the other major erythroid factor, GATA-1, was removed from chromosome. Moreover, despite mitotic chromatin condensation, the distant regulatory regions and promoters of transcriptionally competent globin gene loci are marked by a preserved histone code consisting in active histone modifications such as H3 acetylation, H3-K4 dimethylation and K79 dimethylation. Further analysis showed that other active genes are also locally marked by the preserved active histone code throughout mitotic inactivation of transcription. Conclusion Our results imply that certain kinds of specific protein factors and active histone modifications function as cellular memory markers for both competent and active genes during mitosis, and serve as a reactivated core for the resumption of transcription when the cells exit mitosis.
Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

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Sahu, Geetaram; Farley, Kalamo; El-Hage, Nazira; Aiamkitsumrit, Benjamas; Fassnacht, Ryan; Kashanchi, Fatah; Ochem, Alex; Simon, Gary L.; Karn, Jonathan; Hauser, Kurt F.; Tyagi, Mudit

2015-01-01

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-κB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-κB at 276th serine residue. These modifications enhance the interaction of NF-κB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication. PMID:25980739
Early growth response-1 negative feedback regulates skeletal muscle postprandial insulin sensitivity via activating Ptp1b transcription.

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Wu, Jing; Tao, Wei-Wei; Chong, Dan-Yang; Lai, Shan-Shan; Wang, Chuang; Liu, Qi; Zhang, Tong-Yu; Xue, Bin; Li, Chao-Jun

2018-03-15

Postprandial insulin desensitization plays a critical role in maintaining whole-body glucose homeostasis by avoiding the excessive absorption of blood glucose; however, the detailed mechanisms that underlie how the major player, skeletal muscle, desensitizes insulin action remain to be elucidated. Herein, we report that early growth response gene-1 ( Egr-1) is activated by insulin in skeletal muscle and provides feedback inhibition that regulates insulin sensitivity after a meal. The inhibition of the transcriptional activity of Egr-1 enhanced the phosphorylation of the insulin receptor (InsR) and Akt, thus increasing glucose uptake in L6 myotubes after insulin stimulation, whereas overexpression of Egr-1 decreased insulin sensitivity. Furthermore, deletion of Egr-1 in the skeletal muscle improved systemic insulin sensitivity and glucose tolerance, which resulted in lower blood glucose levels after refeeding. Mechanistic analysis demonstrated that EGR-1 inhibited InsR phosphorylation and glucose uptake in skeletal muscle by binding to the proximal promoter region of protein tyrosine phosphatase-1B (PTP1B) and directly activating transcription. PTP1B knockdown largely restored insulin sensitivity and enhanced glucose uptake, even under conditions of EGR-1 overexpression. Our results indicate that EGR-1/PTP1B signaling negatively regulates postprandial insulin sensitivity and suggest a potential therapeutic target for the prevention and treatment of excessive glucose absorption.-Wu, J., Tao, W.-W., Chong, D.-Y., Lai, S.-S., Wang, C., Liu, Q., Zhang, T.-Y., Xue, B., Li, C.-J. Early growth response-1 negative feedback regulates skeletal muscle postprandial insulin sensitivity via activating Ptp1b transcription.
Sonic hedgehog stimulates glycolysis and proliferation of breast cancer cells: Modulation of PFKFB3 activation

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Ge, Xin; Lyu, Pengwei; Gu, Yuanting; Li, Lin; Li, Jingruo; Wang, Yan; Zhang, Linfeng [Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan (China); Fu, Chao [Department of Ultrasonography, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan (China); Cao, Zhang, E-mail: zzzhangcao@126.com [Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan (China)

2015-08-28

Sonic hesgehog (Shh) signaling has been reported to play an essential role in cancer progression. The mechanism of Shh involved in breast cancer carcinogenesis remains unclear. The present study sought to explore whether Shh signaling could regulate the glycolytic metabolism in breast cancers. Overexpression of the smoothed (Smo) and Gli-1 was found in human primary breast cancers. The expressions of Shh and Gli-1 correlated significantly with tumor size and tumor stage. In vitro, human recombinant Shh (rShh) triggered Smo and Gli-1 expression, promoted glucose utilization and lactate production, and accelerated cell proliferation in MCF-7 and MDA-MB-231 cells. Notably, rShh did not alter 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) expression but augmented PFKFB3 phosphorylation on ser{sup 461}, along with elevated fructose-2,6-bisphosphate (F2,6BP) generation by MCF-7 and MDA-MB-231 cells. This effect could be dampened by Smo siRNA but not by Gli-1 siRNA. In addition, our data showed the upregulated expressions of MAPK by rShh and elevatory PFKFB3 phosphorylation by p38/MAPK activated kinase (MK2). In conclusion, our study characterized a novel role of Shh in promoting glycolysis and proliferation of breast cancer cells via PFKFB3 phosphorylation, which was mediated by Smo and p38/MK2. - Highlights: • Overexpression of Smo and Gli-1 was found in human primary breast cancers. • Shh promoted glucose utilization, lactate production, and cell proliferation. • Shh did not alter PFKFB3 expression but augmented PFKFB3 phosphorylation on ser461. • Shh acts on PFKFB3 phosphorylation via Smo and p38 MAPK/MK2.
Sonic hedgehog stimulates glycolysis and proliferation of breast cancer cells: Modulation of PFKFB3 activation

International Nuclear Information System (INIS)

Ge, Xin; Lyu, Pengwei; Gu, Yuanting; Li, Lin; Li, Jingruo; Wang, Yan; Zhang, Linfeng; Fu, Chao; Cao, Zhang

2015-01-01

Sonic hesgehog (Shh) signaling has been reported to play an essential role in cancer progression. The mechanism of Shh involved in breast cancer carcinogenesis remains unclear. The present study sought to explore whether Shh signaling could regulate the glycolytic metabolism in breast cancers. Overexpression of the smoothed (Smo) and Gli-1 was found in human primary breast cancers. The expressions of Shh and Gli-1 correlated significantly with tumor size and tumor stage. In vitro, human recombinant Shh (rShh) triggered Smo and Gli-1 expression, promoted glucose utilization and lactate production, and accelerated cell proliferation in MCF-7 and MDA-MB-231 cells. Notably, rShh did not alter 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) expression but augmented PFKFB3 phosphorylation on ser 461 , along with elevated fructose-2,6-bisphosphate (F2,6BP) generation by MCF-7 and MDA-MB-231 cells. This effect could be dampened by Smo siRNA but not by Gli-1 siRNA. In addition, our data showed the upregulated expressions of MAPK by rShh and elevatory PFKFB3 phosphorylation by p38/MAPK activated kinase (MK2). In conclusion, our study characterized a novel role of Shh in promoting glycolysis and proliferation of breast cancer cells via PFKFB3 phosphorylation, which was mediated by Smo and p38/MK2. - Highlights: • Overexpression of Smo and Gli-1 was found in human primary breast cancers. • Shh promoted glucose utilization, lactate production, and cell proliferation. • Shh did not alter PFKFB3 expression but augmented PFKFB3 phosphorylation on ser461. • Shh acts on PFKFB3 phosphorylation via Smo and p38 MAPK/MK2
Kurarinol induces hepatocellular carcinoma cell apoptosis through suppressing cellular signal transducer and activator of transcription 3 signaling

International Nuclear Information System (INIS)

Shu, Guangwen; Yang, Jing; Zhao, Wenhao; Xu, Chan; Hong, Zongguo; Mei, Zhinan; Yang, Xinzhou

2014-01-01

Kurarinol is a flavonoid isolated from roots of the medical plant Sophora flavescens. However, its cytotoxic activity against hepatocellular carcinoma (HCC) cells and toxic effects on mammalians remain largely unexplored. Here, the pro-apoptotic activities of kurarinol on HCC cells and its toxic impacts on tumor-bearing mice were evaluated. The molecular mechanisms underlying kurarinol-induced HCC cell apoptosis were also investigated. We found that kurarinol dose-dependently provoked HepG2, Huh-7 and H22 HCC cell apoptosis. In addition, kurarinol gave rise to a considerable decrease in the transcriptional activity of signal transducer and activator of transcription 3 (STAT3) in HCC cells. Suppression of STAT3 signaling is involved in kurarinol-induced HCC cell apoptosis. In vivo studies showed that kurarinol injection substantially induced transplanted H22 cell apoptosis with low toxic impacts on tumor-bearing mice. Similarly, the transcriptional activity of STAT3 in transplanted tumor tissues was significantly suppressed after kurarinol treatment. Collectively, our current research demonstrated that kurarinol has the capacity of inducing HCC cell apoptosis both in vitro and in vivo with undetectable toxic impacts on the host. Suppressing STAT3 signaling is implicated in kurarinol-mediated HCC cell apoptosis. - Highlights: • Kurarinol induces hepatocellular carcinoma (HCC) cell apoptosis. • Kurarinol induces HCC cell apoptosis via inhibiting STAT3. • Kurarinol exhibits low toxic effects on tumor-bearing animals
Complex formation of p65/RelA with nuclear Akt1 for enhanced transcriptional activation of NF-κB

International Nuclear Information System (INIS)

Kwon, Osong; Kim, Kyung A; He, Long; Jung, Mira; Jeong, Sook Jung; Ahn, Jong Seog; Kim, Bo Yeon

2008-01-01

Akt1 was revealed to interact with Ki-Ras in the cytoplasm of Ki-Ras-transformed human prostate epithelial cells, 267B1/K-ras. Moreover, p65/RelA in the nucleus was found to interact with both Ki-Ras and Akt1, suggesting the nuclear translocation of Akt1:Ki-Ras complex for NF- κB activation. In support of this, compared with wild type Akt1, the dominant negative Akt1 mutant was decreased in its nuclear expression, reducing the Ki-Ras-induced NF-κB transcriptional activation. Moreover, inhibitors of Ras (sulindac sulfide and farnesyltransferase inhibitor I) or PI3K/Akt (wortmannin), reduced the amounts of Akt1 and Ki-Ras in the nucleus as well as partial NF-κB activity. The complete inhibition of Ki-Ras-induced NF-κB activation, however, could only be obtained by combined treatment with wortmannin and proteasome inhibitor-1. Accordingly, clonogenic assay showed Akt1 contribution to IκBα-mediated NF-κB activation for oncogenic cell growth by Ki-Ras. Our data suggest a crucial role of Ki-Ras:Akt1 complex in NF-κB transcriptional activation and enhancement of cell survival
Deciphering the role of the signal- and Sty1 kinase-dependent phosphorylation of the stress-responsive transcription factor Atf1 on gene activation.

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Salat-Canela, Clàudia; Paulo, Esther; Sánchez-Mir, Laura; Carmona, Mercè; Ayté, José; Oliva, Baldo; Hidalgo, Elena

2017-08-18

Adaptation to stress triggers the most dramatic shift in gene expression in fission yeast ( Schizosaccharomyces pombe ), and this response is driven by signaling via the MAPK Sty1. Upon activation, Sty1 accumulates in the nucleus and stimulates expression of hundreds of genes via the nuclear transcription factor Atf1, including expression of atf1 itself. However, the role of stress-induced, Sty1-mediated Atf1 phosphorylation in transcriptional activation is unclear. To this end, we expressed Atf1 phosphorylation mutants from a constitutive promoter to uncouple Atf1 activity from endogenous, stress-activated Atf1 expression. We found that cells expressing a nonphosphorylatable Atf1 variant are sensitive to oxidative stress because of impaired transcription of a subset of stress genes whose expression is also controlled by another transcription factor, Pap1. Furthermore, cells expressing a phospho-mimicking Atf1 mutant display enhanced stress resistance, and although expression of the Pap1-dependent genes still relied on stress induction, another subset of stress-responsive genes was constitutively expressed in these cells. We also observed that, in cells expressing the phospho-mimicking Atf1 mutant, the presence of Sty1 was completely dispensable, with all stress defects of Sty1-deficient cells being suppressed by expression of the Atf1 mutant. We further demonstrated that Sty1-mediated Atf1 phosphorylation does not stimulate binding of Atf1 to DNA but, rather, establishes a platform of interactions with the basal transcriptional machinery to facilitate transcription initiation. In summary, our results provide evidence that Atf1 phosphorylation by the MAPK Sty1 is required for oxidative stress responses in fission yeast cells by promoting transcription initiation. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.
Recent behavioral history modifies coupling between cell activity and Arc gene transcription in hippocampal CA1 neurons.

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Guzowski, John F; Miyashita, Teiko; Chawla, Monica K; Sanderson, Jennifer; Maes, Levi I; Houston, Frank P; Lipa, Peter; McNaughton, Bruce L; Worley, Paul F; Barnes, Carol A

2006-01-24

The ability of neurons to alter their transcriptional programs in response to synaptic input is of fundamental importance to the neuroplastic mechanisms underlying learning and memory. Because of technical limitations of conventional gene detection methods, the current view of activity-dependent neural transcription derives from experiments in which neurons are assumed quiescent until a signaling stimulus is given. The present study was designed to move beyond this static model by examining how earlier episodes of neural activity influence transcription of the immediate-early gene Arc. Using a sensitive FISH method that detects primary transcript at genomic alleles, the proportion of hippocampal CA1 neurons that activate transcription of Arc RNA was constant at approximately 40% in response to both a single novel exploration session and daily sessions repeated over 9 days. This proportion is similar to the percentage of active neurons defined electrophysiologically. However, this close correspondence was disrupted in rats exposed briefly, but repeatedly, to the same environment within a single day. Arc transcription in CA1 neurons declined dramatically after as few as four 5-min sessions, despite stable electrophysiological activity during all sessions. Additional experiments indicate that the decrement in Arc transcription occurred at the cellular, rather than synaptic level, and was not simply linked to habituation to novelty. Thus, the neural genomic response is governed by recent, but not remote, cell firing history in the behaving animal. This state-dependence of neuronal transcriptional coupling provides a mechanism of metaplasticity and may regulate capacity for synaptic modification in neural networks.
Downregulated long non-coding RNA MEG3 in breast cancer regulates proliferation, migration and invasion by depending on p53’s transcriptional activity

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Sun, Lin [West Biostatistics and Cost-effectiveness Research Center, Medical Insurance Office, West China Hospital of Sichuan University, 610041, Sichuan (China); Li, Yu [Department of Anesthesiology, West China Hospital, Sichuan University, 610041, Sichuan (China); Yang, Bangxiang, E-mail: b19933009@qq.coom [Department of Pain Management, West China Hospital of Sichuan University, 610041, Sichuan (China)

2016-09-09

Long non-coding RNAs (lncRNAs) was found to play critical roles in tumorigenesis, hence, screen of tumor-related lncRNAs, identification of their biological roles is important for understanding the processes of tumorigenesis. In this study, we identified the expressing difference of several tumor-related lncRNAs in breast cancer samples and found that, MEG3, which is downregulated in non-small cell lung cancer (NSCLC) tumor tissues, is also downregulated in breast cancer samples compared with adjacent tissues. For figuring out the effect of MEG3 in breast cancer cells MCF7 and MB231, we overexpressed MEG3 in these cells, and found that it resulted the inhibition of proliferation, colony formation, migration and invasion capacities by enhancing p53’s transcriptional activity on its target genes, including p21, Maspin and KAI1. MEG3 presented similar effects in MB157, which is a p53-null breast cancer cell line, when functional p53 but not p53R273H mutant, which lacks transcriptional activity, was introduced. Surprisingly, overexpression of MEG3 activates p53’s transcriptional activity by decreasing MDM2’s transcription level, and thus stabilizes and accumulates P53. Taken together, our findings indicate that MEG3 is downregulated in breast cancer tissues and affects breast cancer cells’ malignant behaviors, which indicate MEG3 a potential therapeutic target for breast cancer. - Highlights: • MEG3 RNA is widely downregulated in breast tumor tissue. • MEG3 regulates P53 indirectly through transcriptional regulation of MDM2. • Under unstressed condition, MEG3-related P53 accumulation transcriptionally activates p53’s target genes. • MEG3 expression level tightly regulates proliferation, colony formation, migration and invasion in breast tumor cells.

Structure of noncoding RNA is a determinant of function of RNA binding proteins in transcriptional regulation

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Oyoshi Takanori

2012-01-01

Full Text Available Abstract The majority of the noncoding regions of mammalian genomes have been found to be transcribed to generate noncoding RNAs (ncRNAs, resulting in intense interest in their biological roles. During the past decade, numerous ncRNAs and aptamers have been identified as regulators of transcription. 6S RNA, first described as a ncRNA in E. coli, mimics an open promoter structure, which has a large bulge with two hairpin/stalk structures that regulate transcription through interactions with RNA polymerase. B2 RNA, which has stem-loops and unstructured single-stranded regions, represses transcription of mRNA in response to various stresses, including heat shock in mouse cells. The interaction of TLS (translocated in liposarcoma with CBP/p300 was induced by ncRNAs that bind to TLS, and this in turn results in inhibition of CBP/p300 histone acetyltransferase (HAT activity in human cells. Transcription regulator EWS (Ewing's sarcoma, which is highly related to TLS, and TLS specifically bind to G-quadruplex structures in vitro. The carboxy terminus containing the Arg-Gly-Gly (RGG repeat domains in these proteins are necessary for cis-repression of transcription activation and HAT activity by the N-terminal glutamine-rich domain. Especially, the RGG domain in the carboxy terminus of EWS is important for the G-quadruplex specific binding. Together, these data suggest that functions of EWS and TLS are modulated by specific structures of ncRNAs.
The metabolic sensors FXRα, PGC-1α, and SIRT1 cooperatively regulate hepatitis B virus transcription.

Science.gov (United States)

Curtil, Claire; Enache, Liviu S; Radreau, Pauline; Dron, Anne-Gaëlle; Scholtès, Caroline; Deloire, Alexandre; Roche, Didier; Lotteau, Vincent; André, Patrice; Ramière, Christophe

2014-03-01

Hepatitis B virus (HBV) genome transcription is highly dependent on liver-enriched, metabolic nuclear receptors (NRs). Among others, NR farnesoid X receptor α (FXRα) enhances HBV core promoter activity and pregenomic RNA synthesis. Interestingly, two food-withdrawal-induced FXRα modulators, peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) and deacetylase SIRT1, have been found to be associated with HBV genomes ex vivo. Whereas PGC-1α induction was shown to increase HBV replication, the effect of SIRT1 on HBV transcription remains unknown. Here, we showed that, in hepatocarcinoma-derived Huh-7 cells, combined activation of FXRα by GW4064 and SIRT1 by activator 3 increased HBV core promoter-controlled luciferase expression by 25-fold, compared with a 10-fold increase with GW4064 alone. Using cell lines differentially expressing FXRα in overexpression and silencing experiments, we demonstrated that SIRT1 activated the core promoter in an FXRα- and PGC-1α-dependent manner. Maximal activation (>150-fold) was observed in FXRα- and PGC-1α-overexpressing Huh-7 cells treated with FXRα and SIRT1 activators. Similarly, in cells transfected with full-length HBV genomes, maximal induction (3.5-fold) of core promoter-controlled synthesis of 3.5-kb RNA was observed in the same conditions of transfection and treatments. Thus, we identified a subnetwork of metabolic factors regulating HBV replication, strengthening the hypothesis that transcription of HBV and metabolic genes is similarly controlled.
Identification of DNA-binding sites for the activator involved in late transcription of the temperate lactococcal phage TP901-1

DEFF Research Database (Denmark)

Pedersen, Margit; Kilstrup, Mogens; Hammer, Karin

2006-01-01

Alt, encoded by the lactococcal phage TP901-1, is needed for late transcription. We identify Alt as a DNA-binding protein, and footprint analysis shows that Alt binds to a region containing four imperfect direct repeats (ALT boxes) located -76 to -32 relative to the P-late transcriptional start...... site. The importance of the ALT boxes was confirmed by deletion of one or two ALT boxes and by introducing mutations in ALT boxes 1 and 4. Alt is proposed to act as a tetramer or higher multimer activating transcription of TP901-1 late genes by binding to the four ALT boxes, and bending of the DNA may...... be important for transcriptional activation of P-late. Furthermore, our results suggest that DNA replication may be required for late transcription in TP901-1. Additionally, we identify gp28 of the related lactococcal phage Tuc2009 as an activator and show that the activators required for late transcription...
Relationship between ADD1 Gly460Trp gene polymorphism and essential hypertension in Madeira Island.

Science.gov (United States)

Sousa, Ana Célia; Palma Dos Reis, Roberto; Pereira, Andreia; Borges, Sofia; Freitas, Ana Isabel; Guerra, Graça; Góis, Teresa; Rodrigues, Mariana; Henriques, Eva; Freitas, Sónia; Ornelas, Ilídio; Pereira, Décio; Brehm, António; Mendonça, Maria Isabel

2017-10-01

Essential hypertension (EH) is a complex disease in which physiological, environmental, and genetic factors are involved in its genesis. The genetic variant of the alpha-adducin gene (ADD1) has been described as a risk factor for EH, but with controversial results.The objective of this study was to evaluate the association of ADD1 (Gly460Trp) gene polymorphism with the EH risk in a population from Madeira Island.A case-control study with 1614 individuals of Caucasian origin was performed, including 817 individuals with EH and 797 controls. Cases and controls were matched for sex and age, by frequency-matching method. All participants collected blood for biochemical and genotypic analysis for the Gly460Trp polymorphism. We further investigated which variables were independently associated to EH, and, consequently, analyzed their interactions.In our study, we found a significant association between the ADD1 gene polymorphism and EH (odds ratio 2.484, P = .01). This association remained statistically significant after the multivariate analysis (odds ratio 2.548, P = .02).The ADD1 Gly460Trp gene polymorphism is significantly and independently associated with EH risk in our population. The knowledge of genetic polymorphisms associated with EH is of paramount importance because it leads to a better understanding of the etiology and pathophysiology of this pathology.
Identification of a novel ZIC3 isoform and mutation screening in patients with heterotaxy and congenital heart disease.

Directory of Open Access Journals (Sweden)

James E J Bedard

Full Text Available Patients with heterotaxy have characteristic cardiovascular malformations, abnormal arrangement of their visceral organs, and midline patterning defects that result from abnormal left-right patterning during embryogenesis. Loss of function of the transcription factor ZIC3 causes X-linked heterotaxy and isolated congenital heart malformations and represents one of the few known monogenic causes of congenital heart disease. The birth incidence of heterotaxy-spectrum malformations is significantly higher in males, but our previous work indicated that mutations within ZIC3 did not account for the male over-representation. Therefore, cross species comparative sequence alignment was used to identify a putative novel fourth exon, and the existence of a novel alternatively spliced transcript was confirmed by amplification from murine embryonic RNA and subsequent sequencing. This transcript, termed Zic3-B, encompasses exons 1, 2, and 4 whereas Zic3-A encompasses exons 1, 2, and 3. The resulting protein isoforms are 466 and 456 amino acid residues respectively, sharing the first 407 residues. Importantly, the last two amino acids in the fifth zinc finger DNA binding domain are altered in the Zic3-B isoform, indicating a potential functional difference that was further evaluated by expression, subcellular localization, and transactivation analyses. The temporo-spatial expression pattern of Zic3-B overlaps with Zic3-A in vivo, and both isoforms are localized to the nucleus in vitro. Both isoforms can transcriptionally activate a Gli binding site reporter, but only ZIC3-A synergistically activates upon co-transfection with Gli3, suggesting that the isoforms are functionally distinct. Screening 109 familial and sporadic male heterotaxy cases did not identify pathogenic mutations in the newly identified fourth exon and larger studies are necessary to establish the importance of the novel isoform in human disease.
Over-expression of Arabidopsis thaliana SFD1/GLY1, the gene encoding plastid localized glycerol-3-phosphate dehydrogenase, increases plastidic lipid content in transgenic rice plants.

Science.gov (United States)

Singh, Vijayata; Singh, Praveen Kumar; Siddiqui, Adnan; Singh, Subaran; Banday, Zeeshan Zahoor; Nandi, Ashis Kumar

2016-03-01

Lipids are the major constituents of all membranous structures in plants. Plants possess two pathways for lipid biosynthesis: the prokaryotic pathway (i.e., plastidic pathway) and the eukaryotic pathway (i.e., endoplasmic-reticulum (ER) pathway). Whereas some plants synthesize galactolipids from diacylglycerol assembled in the plastid, others, including rice, derive their galactolipids from diacylglycerols assembled by the eukaryotic pathway. Arabidopsis thaliana glycerol-3-phosphate dehydrogenase (G3pDH), coded by SUPPRESSOR OF FATTY ACID DESATURASE 1 (SFD1; alias GLY1) gene, catalyzes the formation of glycerol 3-phosphate (G3p), the backbone of many membrane lipids. Here SFD1 was introduced to rice as a transgene. Arabidopsis SFD1 localizes in rice plastids and its over-expression increases plastidic membrane lipid content in transgenic rice plants without any major impact on ER lipids. The results suggest that over-expression of plastidic G3pDH enhances biosynthesis of plastid-localized lipids in rice. Lipid composition in the transgenic plants is consistent with increased phosphatidylglycerol synthesis in the plastid and increased galactolipid synthesis from diacylglycerol produced via the ER pathway. The transgenic plants show a higher photosynthetic assimilation rate, suggesting a possible application of this finding in crop improvement.
Activation of transcription factor AP-2 mediates UVA radiation- and singlet oxygen-induced expression of the human intercellular adhesion molecule 1 gene

International Nuclear Information System (INIS)

Grether-Beck, S.; Olaizola-Horn, S.; Schmitt, H.; Grewe, M.

1996-01-01

UVA radiation is the major component of the UV solar spectrum that reaches the earth, and the therapeutic application of UVA radiation is increasing in medicine. Analysis of the cellular effects of UVA radiation has revealed that exposure of human cells to UVA radiation at physiological doses leads to increased gene expression and that this UVA response is primarily mediated through the generation of singlet oxygen. In this study, the mechanisms by which UVA radiation induces transcriptional activation of the human intercellular adhesion molecule 1 (ICAM-1) were examined. UVA radiation was capable of inducing activation of the human ICAM-1 promoter and increasing OCAM-1 mRNA and protein expression. These UVA radiation effects were inhibited by singlet oxygen quenchers, augmented by enhancement of singlet oxygen life-time, and mimicked in unirradiated cells by a singlet oxygen-generating system. UVA radiation as well as singlet oxygen-induced ICAM-1 promoter activation required activation of the transcription factor AP-2. Accordingly, both stimuli activated AP-2, and deletion of the putative AP-2-binding site abrogated ICAM-1 promoter activation in this system. This study identified the AP-2 site as the UVA radiation- and singlet oxygen-responsive element of the human ICAM-1 gene. The capacity of UVA radiation and/or singlet oxygen to induce human gene expression through activation of AP-2 indicates a previously unrecognized role of this transcription factor in the mammalian stress response. 38 refs., 3 figs., 3 tabs
E2F1 transcription is induced by genotoxic stress through ATM/ATR activation.

Science.gov (United States)

Carcagno, Abel L; Ogara, María F; Sonzogni, Silvina V; Marazita, Mariela C; Sirkin, Pablo F; Ceruti, Julieta M; Cánepa, Eduardo T

2009-05-01

E2F1, a member of the E2F family of transcription factors, plays a critical role in controlling both cell cycle progression and apoptotic cell death in response to DNA damage and oncogene activation. Following genotoxic stresses, E2F1 protein is stabilized by phosphorylation and acetylation driven to its accumulation. The aim of the present work was to examine whether the increase in E2F1 protein levels observed after DNA damage is only a reflection of an increase in E2F1 protein stability or is also the consequence of enhanced transcription of the E2F1 gene. The data presented here demonstrates that UV light and other genotoxics induce the transcription of E2F1 gene in an ATM/ATR dependent manner, which results in increasing E2F1 mRNA and protein levels. After genotoxic stress, transcription of cyclin E, an E2F1 target gene, was significantly induced. This induction was the result of two well-differentiated effects, one of them dependent on de novo protein synthesis and the other on the protein stabilization. Our results strongly support a transcriptional effect of DNA damaging agents on E2F1 expression. The results presented herein uncover a new mechanism involving E2F1 in response to genotoxic stress.
A cyclic carbo-isosteric penta-depsipeptide: cyclo(Phe1–d-Ala2–Gly3–Phe4–APO5

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Stéphanie M. Guéret

2015-01-01

Full Text Available The title compound, cyclo(Phe1–d-Ala2–Gly3–Phe4–APO5, C26H32N4O5, is the minor diastereoisomer of a cyclic penta-peptidomimetic analogue containing a novel 2-aminopropyl lactone (APO motif, which displays the same number of atoms as the native amino acid glycine and has a methyl group in place of the carbonyl O atom. The crystal structure presented here allows the analysis of the secondary structure of this unprecedented cyclic carbo-isosteric depsipeptide. The conformation of the central ring is stabilized by an intramolecular N—H...O hydrogen bond between the carbonyl O atom of the first residue (Phe1 and the amide group H atom of the fourth residue (Phe4. Based on the previously reported hydrogen bond and on the values of the torsion angles ϕ and ψ, the loop formed by the first, second, third and fourth residues (Phe1, d-Ala2, Gly3 and Phe4 can be classified as a type II′ β-turn. The loop around the new peptidomimetic motif, on the other hand, resembles an open γ-turn containing a weak N—H...O hydrogen bond between the carbonyl group O atom of the fourth residue (Phe4 and the amide unit H atom of the first residue (Phe1. In the crystal, the peptidomimetic molecules are arranged in chains along the b-axis direction. Within such a chain, the molecules of the structure are linked via N—H...O hydrogen bonds between the amide group H atom of the secondary residue (d-Ala2 and the carboxy unit O atom of the fourth residue (Phe4 in a neighboring molecule. The newly formed methyl stereocentre of the APO peptidomimetic motif (APO5 was obtained as the minor diastereoisomer in a ring-closing reductive amination reaction and adopts an R configuration.
Heterochromatin protein 1 gamma and IκB kinase alpha interdependence during tumour necrosis factor gene transcription elongation in activated macrophages.

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Thorne, James L; Ouboussad, Lylia; Lefevre, Pascal F

2012-09-01

IκB kinase α (IKKα) is part of the cytoplasmic IKK complex regulating nuclear factor-κB (NF-κB) release and translocation into the nucleus in response to pro-inflammatory signals. IKKα can also be recruited directly to the promoter of NF-κB-dependent genes by NF-κB where it phosphorylates histone H3 at serine 10, triggering recruitment of the bromodomain-containing protein 4 and the positive transcription elongation factor b. Herein, we report that IKKα travels with the elongating form of ribonucleic acid polymerase II together with heterochromatin protein 1 gamma (HP1γ) at NF-κB-dependent genes in activated macrophages. IKKα binds to and phosphorylates HP1γ, which in turn controls IKKα binding to chromatin and phosphorylation of the histone variant H3.3 at serine 31 within transcribing regions. Downstream of transcription end sites, IKKα accumulates with its inhibitor the CUE-domain containing protein 2, suggesting a link between IKKα inactivation and transcription termination.
The oncoprotein HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote the proliferation of breast cancer cells

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Zhang, Yingyi; Zhao, Yu; Li, Leilei; Shen, Yu; Cai, Xiaoli; Zhang, Xiaodong; Ye, Lihong

2013-01-01

Highlights: •HBXIP is able to upregulate the expression of PDGFB in breast cancer cells. •HBXIP serves as a coactivator of activating transcription factor Sp1. •HBXIP stimulates the PDGFB promoter via activating transcription factor Sp1. •HBXIP promotes the proliferation of breast cancer cell via upregulating PDGFB. -- Abstract: We have reported that the oncoprotein hepatitis B virus X-interacting protein (HBXIP) acts as a novel transcriptional coactivator to promote proliferation and migration of breast cancer cells. Previously, we showed that HBXIP was able to activate nuclear factor-κB (NF-κB) in breast cancer cells. As an oncogene, the platelet-derived growth factor beta polypeptide (PDGFB) plays crucial roles in carcinogenesis. In the present study, we found that both HBXIP and PDGFB were highly expressed in breast cancer cell lines. Interestingly, HBXIP was able to increase transcriptional activity of NF-κB through PDGFB, suggesting that HBXIP is associated with PDGFB in the cells. Moreover, HBXIP was able to upregulate PDGFB at the levels of mRNA, protein and promoter in the cells. Then, we identified that HBXIP stimulated the promoter of PDGFB through activating transcription factor Sp1. In function, HBXIP enhanced the proliferation of breast cancer cells through PDGFB in vitro. Thus, we conclude that HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote proliferation of breast cancer cells
The oncoprotein HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote the proliferation of breast cancer cells

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Zhang, Yingyi; Zhao, Yu; Li, Leilei; Shen, Yu; Cai, Xiaoli [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China); Zhang, Xiaodong, E-mail: zhangxd@nankai.edu.cn [Department of Cancer Research, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071 (China); Ye, Lihong, E-mail: yelihong@nankai.edu.cn [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)

2013-05-03

Highlights: •HBXIP is able to upregulate the expression of PDGFB in breast cancer cells. •HBXIP serves as a coactivator of activating transcription factor Sp1. •HBXIP stimulates the PDGFB promoter via activating transcription factor Sp1. •HBXIP promotes the proliferation of breast cancer cell via upregulating PDGFB. -- Abstract: We have reported that the oncoprotein hepatitis B virus X-interacting protein (HBXIP) acts as a novel transcriptional coactivator to promote proliferation and migration of breast cancer cells. Previously, we showed that HBXIP was able to activate nuclear factor-κB (NF-κB) in breast cancer cells. As an oncogene, the platelet-derived growth factor beta polypeptide (PDGFB) plays crucial roles in carcinogenesis. In the present study, we found that both HBXIP and PDGFB were highly expressed in breast cancer cell lines. Interestingly, HBXIP was able to increase transcriptional activity of NF-κB through PDGFB, suggesting that HBXIP is associated with PDGFB in the cells. Moreover, HBXIP was able to upregulate PDGFB at the levels of mRNA, protein and promoter in the cells. Then, we identified that HBXIP stimulated the promoter of PDGFB through activating transcription factor Sp1. In function, HBXIP enhanced the proliferation of breast cancer cells through PDGFB in vitro. Thus, we conclude that HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote proliferation of breast cancer cells.
OVO homologue-like 1 (Ovol1) transcription factor: a novel target of neurogenin-3 in rodent pancreas.

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Vetere, A; Li, W-C; Paroni, F; Juhl, K; Guo, L; Nishimura, W; Dai, X; Bonner-Weir, S; Sharma, A

2010-01-01

The basic helix-loop-helix transcription factor neurogenin-3 (NGN3) commits the fates of pancreatic progenitors to endocrine cell types, but knowledge of the mechanisms regulating the choice between proliferation and differentiation of these progenitors is limited. Using a chromatin immunoprecipitation cloning approach, we searched for direct targets of NGN3 and identified a zinc-finger transcription factor, OVO homologue-like 1 (OVOL1). Transactivation experiments were carried out to elucidate the functional role of NGN3 in Ovol1 gene expression. Embryonic and adult rodents pancreases were immunostained for OVOL1, Ki67 and NGN3. We showed that NGN3 negatively regulates transcription of Ovol1 in an E-box-dependent fashion. The presence of either NGN3 or NEUROD1, but not MYOD, reduced endogenous Ovol1 mRNA. OVOL1 was detected in pancreatic tissue around embryonic day 15.5, after which OVOL1 levels dramatically increased. In embryonic pancreas, OVOL1 protein levels were low in NGN3(+) or Ki67(+) cells, but high in quiescent differentiated cells. OVOL1 presence was maintained in adult pancreas, where it was detected in islets, pancreatic ducts and some acinar cells. Additionally OVOL1 presence was lacking in proliferating ductules in regenerating pancreas and induced in cells as they began to acquire their differentiated phenotype. The timing of OVOL1 appearance in pancreas and its increased levels in differentiated cells suggest that OVOL1 promotes the transition of cells from a proliferating, less-differentiated state to a quiescent more-differentiated state. We conclude that OVOL1, a downstream target of NGN3, may play an important role in regulating the balance between proliferation and differentiation of pancreatic cells.
Carnitine palmitoyltransferase 1A (CPT1A): a transcriptional target of PAX3-FKHR and mediates PAX3-FKHR–dependent motility in alveolar rhabdomyosarcoma cells

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Liu, Lingling; Wang, Yong-Dong; Wu, Jing; Cui, Jimmy; Chen, Taosheng

2012-01-01

Alveolar rhabdomyosarcoma (ARMS) has a high propensity to metastasize, leading to its aggressiveness and a poor survival rate among those with the disease. More than 80% of aggressive ARMSs harbor a PAX3-FKHR fusion transcription factor, which regulates cell migration and promotes metastasis, most likely by regulating the fusion protein’s transcriptional targets. Therefore, identifying druggable transcription targets of PAX3-FKHR that are also downstream effectors of PAX3-FKHR–mediated cell migration and metastasis may lead to novel therapeutic approaches for treating ARMS. To identify genes whose expression is directly affected by the level of PAX3-FKHR in an ARMS cellular-context, we first developed an ARMS cell line in which PAX3-FKHR is stably down-regulated, and showed that stably downregulating PAX3-FKHR in ARMS cells significantly decreased the cells’ motility. We used microarray analysis to identify genes whose expression level decreased when PAX3-FKHR was downregulated. We used mutational analysis, promoter reporter assays, and electrophoretic mobility shift assays to determine whether PAX3-FKHR binds to the promoter region of the target gene. We used siRNA and pharmacologic inhibitor to downregulate the target gene of PAX3-FKHR and investigated the effect of such downregulation on cell motility. We found that when PAX3-FKHR was downregulated, the expression of carnitine palmitoyltransferase 1A (CPT1A) decreased. We showed that PAX3-FKHR binds to a paired-domain binding-site in the CPT1A promoter region, indicating that CPT1A is a novel transcriptional target of PAX3-FKHR. Furthermore, downregulating CPT1A decreased cell motility in ARMS cells, indicating that CPT1A is a downstream effector of PAX3-FKHR–mediated cell migration and metastasis. Taken together, we have identified CPT1A as a novel transcriptional target of PAX3-FKHR and revealed the novel function of CPT1A in promoting cell motility. CPT1A may represent a novel therapeutic target for
Natural variation in monoterpene synthesis in kiwifruit: transcriptional regulation of terpene synthases by NAC and ETHYLENE-INSENSITIVE3-like transcription factors.

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Nieuwenhuizen, Niels J; Chen, Xiuyin; Wang, Mindy Y; Matich, Adam J; Perez, Ramon Lopez; Allan, Andrew C; Green, Sol A; Atkinson, Ross G

2015-04-01

Two kiwifruit (Actinidia) species with contrasting terpene profiles were compared to understand the regulation of fruit monoterpene production. High rates of terpinolene production in ripe Actinidia arguta fruit were correlated with increasing gene and protein expression of A. arguta terpene synthase1 (AaTPS1) and correlated with an increase in transcript levels of the 2-C-methyl-D-erythritol 4-phosphate pathway enzyme 1-deoxy-D-xylulose-5-phosphate synthase (DXS). Actinidia chinensis terpene synthase1 (AcTPS1) was identified as part of an array of eight tandemly duplicated genes, and AcTPS1 expression and terpene production were observed only at low levels in developing fruit. Transient overexpression of DXS in Nicotiana benthamiana leaves elevated monoterpene synthesis by AaTPS1 more than 100-fold, indicating that DXS is likely to be the key step in regulating 2-C-methyl-D-erythritol 4-phosphate substrate flux in kiwifruit. Comparative promoter analysis identified potential NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor) and ETHYLENE-INSENSITIVE3-like transcription factor (TF) binding sites in the AaTPS1 promoter, and cloned members of both TF classes were able to activate the AaTPS1 promoter in transient assays. Electrophoretic mobility shift assays showed that AaNAC2, AaNAC3, and AaNAC4 bind a 28-bp fragment of the proximal NAC binding site in the AaTPS1 promoter but not the A. chinensis AcTPS1 promoter, where the NAC binding site was mutated. Activation could be restored by reintroducing multiple repeats of the 12-bp NAC core-binding motif. The absence of NAC transcriptional activation in ripe A. chinensis fruit can account for the low accumulation of AcTPS1 transcript, protein, and monoterpene volatiles in this species. These results indicate the importance of NAC TFs in controlling monoterpene production and other traits in ripening fruits. © 2015 American
Effect of DNA methylation profile on OATP3A1 and OATP4A1 transcript levels in colorectal cancer.

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Rawłuszko-Wieczorek, Agnieszka Anna; Horst, Nikodem; Horbacka, Karolina; Bandura, Artur Szymon; Świderska, Monika; Krokowicz, Piotr; Jagodziński, Paweł Piotr

2015-08-01

Epidemiological studies indicate that 17β-estradiol (E2) prevents colorectal cancer (CRC). Organic anion transporting polypeptides (OATPs) are involved in the cellular uptake of various endogenous and exogenous substrates, including hormone conjugates. Because transfer of estrone sulfate (E1-S) can contribute to intra-tissue conversion of estrone to the biologically active form -E2, it is evident that the expression patterns of OATPs may be relevant to the analysis of CRC incidence and therapy. We therefore evaluated DNA methylation and transcript levels of two members of the OATP family, OATP3A1 and OATP4A1, that may be involved in E1-S transport in colorectal cancer patients. We detected a significant reduction in OATP3A1 and a significant increase in OATP4A1 mRNA levels in cancerous tissue, compared with histopathologically unchanged tissue (n=103). Moreover, we observed DNA hypermethylation in the OATP3A1 promoter region in a small subset of CRC patients and in HCT116 and Caco-2 colorectal cancer cell lines. We also observed increased OATP3A1 transcript following treatment with 5-aza-2-deoxycytidine and sodium butyrate. The OATP4A1 promoter region was hypomethylated in analyzed tissues and CRC cell lines and was not affected by these treatments. Our results suggest a potential mechanism for OATP3A1 downregulation that involves DNA methylation during colorectal carcinogenesis. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
Effects of Pro-Gly-Pro tripeptide on the dopamine system.

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Meshavkin, V K; Batishcheva, E Yu; Kost, N V; Sokolov, O Yu; Trufanova, A V; Samonina, G E

2011-08-01

Tripeptide Pro-Gly-Pro interacted with dopamine receptors in vitro and reduced behavioral manifestations of apomorphine-induced hyperfunction of the dopamine system in verticalization, stereotypy, and yawning tests. Presumably, the behavioral effects of Pro-Gly-Pro tripeptide were mediated through post- and presynaptic D(2)and D(3)receptors.
HSF1 transcriptional activity mediates alcohol induction of Vamp2 expression and GABA release

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Florence P. Varodayan

2013-12-01

Full Text Available Many central synapses are highly sensitive to alcohol, and it is now accepted that short-term alterations in synaptic function may lead to longer term changes in circuit function. The regulation of postsynaptic receptors by alcohol has been well studied, but the mechanisms underlying the effects of alcohol on the presynaptic terminal are relatively unexplored. To identify a pathway by which alcohol regulates neurotransmitter release, we recently investigated the mechanism by which ethanol induces the Vamp2 gene, but not Vamp1, in mouse primary cortical cultures. These two genes encode isoforms of synaptobrevin, a vesicular soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE protein required for synaptic vesicle fusion. We found that alcohol activates the transcription factor heat shock factor 1 (HSF1 to induce Vamp2 gene expression, while Vamp1 mRNA levels remain unaffected. As the Vamp2 gene encodes a SNARE protein, we then investigated whether ethanol exposure and HSF1 transcriptional activity alter neurotransmitter release using electrophysiology. We found that alcohol increased the frequency of γ-aminobutyric acid (GABA-mediated miniature IPSCs via HSF1, but had no effect on mEPSCs. Overall, these data indicate that alcohol induces HSF1 transcriptional activity to trigger a specific coordinated adaptation in GABAergic presynaptic terminals. This mechanism could explain some of the changes in synaptic function that occur soon after alcohol exposure, and may underlie some of the more enduring effects of chronic alcohol intake on local circuit function.
Dataset of transcriptional landscape of B cell early activation

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Alexander S. Garruss

2015-09-01

Full Text Available Signaling via B cell receptors (BCR and Toll-like receptors (TLRs result in activation of B cells with distinct physiological outcomes, but transcriptional regulatory mechanisms that drive activation and distinguish these pathways remain unknown. At early time points after BCR and TLR ligand exposure, 0.5 and 2 h, RNA-seq was performed allowing observations on rapid transcriptional changes. At 2 h, ChIP-seq was performed to allow observations on important regulatory mechanisms potentially driving transcriptional change. The dataset includes RNA-seq, ChIP-seq of control (Input, RNA Pol II, H3K4me3, H3K27me3, and a separate RNA-seq for miRNA expression, which can be found at Gene Expression Omnibus Dataset GSE61608. Here, we provide details on the experimental and analysis methods used to obtain and analyze this dataset and to examine the transcriptional landscape of B cell early activation.
First functional polymorphism in CFTR promoter that results in decreased transcriptional activity and Sp1/USF binding

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Taulan, M.; Lopez, E.; Guittard, C.; Rene, C.; Baux, D.; Altieri, J.P.; DesGeorges, M.; Claustres, M.; Romey, M.C.

2007-01-01

Growing evidences show that functionally relevant polymorphisms in various promoters alter both transcriptional activity and affinities of existing protein-DNA interactions, and thus influence disease progression in humans. We previously reported the -94G>T CFTR promoter variant in a female CF patient in whom any known disease-causing mutation has been detected. To investigate whether the -94G>T could be a regulatory variant, we have proceeded to in silico analyses and functional studies including EMSA and reporter gene assays. Our data indicate that the promoter variant decreases basal CFTR transcriptional activity in different epithelial cells and alters binding affinities of both Sp1 and USF nuclear proteins to the CFTR promoter. The present report provides evidence for the first functional polymorphism that negatively affects the CFTR transcriptional activity and demonstrates a cooperative role of Sp1 and USF transcription factors in transactivation of the CFTR gene promoter

The 3' untranslated region of human Cyclin-Dependent Kinase 5 Regulatory subunit 1 contains regulatory elements affecting transcript stability

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Ratti Antonia

2007-12-01

Full Text Available Abstract Background CDK5R1 plays a central role in neuronal migration and differentiation during central nervous system development. CDK5R1 has been implicated in neurodegenerative disorders and proposed as a candidate gene for mental retardation. The remarkable size of CDK5R1 3'-untranslated region (3'-UTR suggests a role in post-transcriptional regulation of CDK5R1 expression. Results The bioinformatic study shows a high conservation degree in mammals and predicts several AU-Rich Elements (AREs. The insertion of CDK5R1 3'-UTR into luciferase 3'-UTR causes a decreased luciferase activity in four transfected cell lines. We identified 3'-UTR subregions which tend to reduce the reporter gene expression, sometimes in a cell line-dependent manner. In most cases the quantitative analysis of luciferase mRNA suggests that CDK5R1 3'-UTR affects mRNA stability. A region, leading to a very strong mRNA destabilization, showed a significantly low half-life, indicating an accelerated mRNA degradation. The 3' end of the transcript, containing a class I ARE, specifically displays a stabilizing effect in neuroblastoma cell lines. We also observed the interaction of the stabilizing neuronal RNA-binding proteins ELAV with the CDK5R1 transcript in SH-SY5Y cells and identified three 3'-UTR sub-regions showing affinity for ELAV proteins. Conclusion Our findings evince the presence of both destabilizing and stabilizing regulatory elements in CDK5R1 3'-UTR and support the hypothesis that CDK5R1 gene expression is post-transcriptionally controlled in neurons by ELAV-mediated mechanisms. This is the first evidence of the involvement of 3'-UTR in the modulation of CDK5R1 expression. The fine tuning of CDK5R1 expression by 3'-UTR may have a role in central nervous system development and functioning, with potential implications in neurodegenerative and cognitive disorders.
The transcription factors Runx3 and ThPOK cross-regulate acquisition of cytotoxic function by human Th1 lymphocytes

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Defrance, Matthieu; Vu Manh, Thien-Phong; Azouz, Abdulkader; Detavernier, Aurélie; Hoyois, Alice; Das, Jishnu; Bizet, Martin; Pollet, Emeline; Tabbuso, Tressy; Calonne, Emilie; van Gisbergen, Klaas; Dalod, Marc; Fuks, François; Goriely, Stanislas

2018-01-01

Cytotoxic CD4 (CD4CTX) T cells are emerging as an important component of antiviral and antitumor immunity, but the molecular basis of their development remains poorly understood. In the context of human cytomegalovirus infection, a significant proportion of CD4 T cells displays cytotoxic functions. We observed that the transcriptional program of these cells was enriched in CD8 T cell lineage genes despite the absence of ThPOK downregulation. We further show that establishment of CD4CTX-specific transcriptional and epigenetic programs occurred in a stepwise fashion along the Th1-differentiation pathway. In vitro, prolonged activation of naive CD4 T cells in presence of Th1 polarizing cytokines led to the acquisition of perforin-dependent cytotoxic activity. This process was dependent on the Th1 transcription factor Runx3 and was limited by the sustained expression of ThPOK. This work elucidates the molecular program of human CD4CTX T cells and identifies potential targets for immunotherapy against viral infections and cancer. PMID:29488879
Glycerol-3-phosphate metabolism in wheat contributes to systemic acquired resistance against Puccinia striiformis f. sp. tritici.

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Yuheng Yang

Full Text Available Glycerol-3-phosphate (G3P is a proposed regulator of plant defense signaling in basal resistance and systemic acquired resistance (SAR. The GLY1-encoded glycerol-3-phosphate dehydrogenase (G3PDH and GLI1-encoded glycerol kinase (GK are two key enzymes involved in the G3P biosynthesis in plants. However, their physiological importance in wheat defense against pathogens remains unclear. In this study, quantification analysis revealed that G3P levels were significantly induced in wheat leaves challenged by the avirulent Puccinia striiformis f. sp. tritici (Pst race CYR23. The transcriptional levels of TaGLY1 and TaGLI1 were likewise significantly induced by avirulent Pst infection. Furthermore, knocking down TaGLY1 and TaGLI1 individually or simultaneously with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS inhibited G3P accumulation and compromised the resistance in the wheat cultivar Suwon 11, whereas the accumulation of salicylic acid (SA and the expression of the SA-induced marker gene TaPR1 in plant leaves were altered significantly after gene silencing. These results suggested that G3P contributes to wheat systemic acquired resistance (SAR against stripe rust, and provided evidence that the G3P function as a signaling molecule is conserved in dicots and monocots. Meanwhile, the simultaneous co-silencing of multiple genes by the VIGS system proved to be a powerful tool for multi-gene functional analysis in plants.
SUMOylation of the KRAB zinc-finger transcription factor PARIS/ZNF746 regulates its transcriptional activity

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Nishida, Tamotsu; Yamada, Yoshiji

2016-01-01

Parkin-interacting substrate (PARIS), a member of the family of Krüppel-associated box (KRAB)-containing zinc-finger transcription factors, is a substrate of the ubiquitin E3 ligase parkin. PARIS represses the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), although the underlying mechanisms remain largely unknown. In the present study, we demonstrate that PARIS can be SUMOylated, and its SUMOylation plays a role in the repression of PGC-1a promoter activity. Protein inhibitor of activated STAT y (PIASy) was identified as an interacting protein of PARIS and shown to enhance its SUMOylation. PIASy repressed PGC-1a promoter activity, and this effect was attenuated by PARIS in a manner dependent on its SUMOylation status. Co-expression of SUMO-1 with PIASy completely repressed PGC-1a promoter activity independently of PARIS expression. PARIS-mediated PGC-1a promoter repression depended on the activity of histone deacetylases (HDAC), whereas PIASy repressed the PGC-1a promoter in an HDAC-independent manner. Taken together, these results suggest that PARIS and PIASy modulate PGC-1a gene transcription through distinct molecular mechanisms. -- Highlights: •PARIS can be SUMOylated in vivo and in vitro. •SUMOylation of PARIS functions in the repression of PGC-1a promoter activity. •PIASy interacts with PARIS and enhances its SUMOylation. •PIASy influences PARIS-mediated repression of PGC-1a promoter activity.
SUMOylation of the KRAB zinc-finger transcription factor PARIS/ZNF746 regulates its transcriptional activity

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Nishida, Tamotsu, E-mail: nishida@gene.mie-u.ac.jp; Yamada, Yoshiji

2016-05-13

Parkin-interacting substrate (PARIS), a member of the family of Krüppel-associated box (KRAB)-containing zinc-finger transcription factors, is a substrate of the ubiquitin E3 ligase parkin. PARIS represses the expression of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), although the underlying mechanisms remain largely unknown. In the present study, we demonstrate that PARIS can be SUMOylated, and its SUMOylation plays a role in the repression of PGC-1a promoter activity. Protein inhibitor of activated STAT y (PIASy) was identified as an interacting protein of PARIS and shown to enhance its SUMOylation. PIASy repressed PGC-1a promoter activity, and this effect was attenuated by PARIS in a manner dependent on its SUMOylation status. Co-expression of SUMO-1 with PIASy completely repressed PGC-1a promoter activity independently of PARIS expression. PARIS-mediated PGC-1a promoter repression depended on the activity of histone deacetylases (HDAC), whereas PIASy repressed the PGC-1a promoter in an HDAC-independent manner. Taken together, these results suggest that PARIS and PIASy modulate PGC-1a gene transcription through distinct molecular mechanisms. -- Highlights: •PARIS can be SUMOylated in vivo and in vitro. •SUMOylation of PARIS functions in the repression of PGC-1a promoter activity. •PIASy interacts with PARIS and enhances its SUMOylation. •PIASy influences PARIS-mediated repression of PGC-1a promoter activity.
NFκB-mediated activation of the cellular FUT3, 5 and 6 gene cluster by herpes simplex virus type 1.

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Nordén, Rickard; Samuelsson, Ebba; Nyström, Kristina

2017-11-01

Herpes simplex virus type 1 has the ability to induce expression of a human gene cluster located on chromosome 19 upon infection. This gene cluster contains three fucosyltransferases (encoded by FUT3, FUT5 and FUT6) with the ability to add a fucose to an N-acetylglucosamine residue. Little is known regarding the transcriptional activation of these three genes in human cells. Intriguingly, herpes simplex virus type 1 activates all three genes simultaneously during infection, a situation not observed in uninfected tissue, pointing towards a virus specific mechanism for transcriptional activation. The aim of this study was to define the underlying mechanism for the herpes simplex virus type 1 activation of FUT3, FUT5 and FUT6 transcription. The transcriptional activation of the FUT-gene cluster on chromosome 19 in fibroblasts was specific, not involving adjacent genes. Moreover, inhibition of NFκB signaling through panepoxydone treatment significantly decreased the induction of FUT3, FUT5 and FUT6 transcriptional activation, as did siRNA targeting of p65, in herpes simplex virus type 1 infected fibroblasts. NFκB and p65 signaling appears to play an important role in the regulation of FUT3, FUT5 and FUT6 transcriptional activation by herpes simplex virus type 1 although additional, unidentified, viral factors might account for part of the mechanism as direct interferon mediated stimulation of NFκB was not sufficient to induce the fucosyltransferase encoding gene cluster in uninfected cells. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
CacyBP/SIP binds ERK1/2 and affects transcriptional activity of Elk-1

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Kilanczyk, Ewa; Filipek, Slawomir; Jastrzebska, Beata; Filipek, Anna

2009-01-01

In this work we showed for the first time that mouse CacyBP/SIP interacts with extracellular signal regulated kinases 1 and 2 (ERK1/2). We also established that a calcium binding protein, S100A6, competes for this interaction. Moreover, the E217K mutant of CacyBP/SIP does not bind significantly to ERK1/2 although it retains the ability to interact with S100A6. Molecular modeling shows that the E217K mutation in the 189-219 CacyBP/SIP fragment markedly changes its electrostatic potential, suggesting that the binding with ERK1/2 might have an electrostatic character. We also demonstrate that CacyBP/SIP-ERK1/2 interaction inhibits phosphorylation of the Elk-1 transcription factor in vitro and in the nuclear fraction of NB2a cells. Altogether, our data suggest that the binding of CacyBP/SIP with ERK1/2 might regulate Elk-1 phosphorylation/transcriptional activity and that S100A6 might further modulate this effect via Ca 2+ -dependent interaction with CacyBP/SIP and competition with ERK1/2.
The role of factor inhibiting HIF (FIH-1 in inhibiting HIF-1 transcriptional activity in glioblastoma multiforme.

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Enfeng Wang

Full Text Available Glioblastoma multiforme (GBM accounts for about 38% of primary brain tumors in the United States. GBM is characterized by extensive angiogenesis induced by vascular growth factors and cytokines. The transcription of these growth factors and cytokines is regulated by the Hypoxia-Inducible-Factor-1(HIF-1, which is a key regulator mediating the cellular response to hypoxia. It is known that Factor Inhibiting HIF-1, or FIH-1, is also involved in the cellular response to hypoxia and has the capability to physically interact with HIF-1 and block its transcriptional activity under normoxic conditions. Delineation of the regulatory role of FIH-1 will help us to better understand the molecular mechanism responsible for tumor growth and progression and may lead to the design of new therapies targeting cellular pathways in response to hypoxia. Previous studies have shown that the chromosomal region of 10q24 containing the FIH-1 gene is often deleted in GBM, suggesting a role for the FIH-1 in GBM tumorigenesis and progression. In the current study, we found that FIH-1 is able to inhibit HIF-mediated transcription of GLUT1 and VEGF-A, even under hypoxic conditions in human glioblastoma cells. FIH-1 has been found to be more potent in inhibiting HIF function than PTEN. This observation points to the possibility that deletion of 10q23-24 and loss or decreased expression of FIH-1 gene may lead to a constitutive activation of HIF-1 activity, an alteration of HIF-1 targets such as GLUT-1 and VEGF-A, and may contribute to the survival of cancer cells in hypoxia and the development of hypervascularization observed in GBM. Therefore FIH-1 can be potential therapeutic target for the treatment of GBM patients with poor prognosis.
Nuclear Matrix protein SMAR1 represses HIV-1 LTR mediated transcription through chromatin remodeling

International Nuclear Information System (INIS)

Sreenath, Kadreppa; Pavithra, Lakshminarasimhan; Singh, Sandeep; Sinha, Surajit; Dash, Prasanta K.; Siddappa, Nagadenahalli B.; Ranga, Udaykumar; Mitra, Debashis; Chattopadhyay, Samit

2010-01-01

Nuclear Matrix and MARs have been implicated in the transcriptional regulation of host as well as viral genes but their precise role in HIV-1 transcription remains unclear. Here, we show that > 98% of HIV sequences contain consensus MAR element in their promoter. We show that SMAR1 binds to the LTR MAR and reinforces transcriptional silencing by tethering the LTR MAR to nuclear matrix. SMAR1 associated HDAC1-mSin3 corepressor complex is dislodged from the LTR upon cellular activation by PMA/TNFα leading to an increase in the acetylation and a reduction in the trimethylation of histones, associated with the recruitment of RNA Polymerase II on the LTR. Overexpression of SMAR1 lead to reduction in LTR mediated transcription, both in a Tat dependent and independent manner, resulting in a decreased virion production. These results demonstrate the role of SMAR1 in regulating viral transcription by alternative compartmentalization of LTR between the nuclear matrix and chromatin.
Stat1 activation attenuates IL-6 induced Stat3 activity but does not alter apoptosis sensitivity in multiple myeloma

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Dimberg Lina Y

2012-07-01

Full Text Available Abstract Background Multiple myeloma (MM is at present an incurable malignancy, characterized by apoptosis-resistant tumor cells. Interferon (IFN treatment sensitizes MM cells to Fas-induced apoptosis and is associated with an increased activation of Signal transducer and activator of transcription (Stat1. The role of Stat1 in MM has not been elucidated, but Stat1 has in several studies been ascribed a pro-apoptotic role. Conversely, IL-6 induction of Stat3 is known to confer resistance to apoptosis in MM. Methods To delineate the role of Stat1 in IFN mediated sensitization to apoptosis, sub-lines of the U-266-1970 MM cell line with a stable expression of the active mutant Stat1C were utilized. The influence of Stat1C constitutive transcriptional activation on endogenous Stat3 expression and activation, and the expression of apoptosis-related genes were analyzed. To determine whether Stat1 alone would be an important determinant in sensitizing MM cells to apoptosis, the U-266-1970-Stat1C cell line and control cells were exposed to high throughput compound screening (HTS. Results To explore the role of Stat1 in IFN mediated apoptosis sensitization of MM, we established sublines of the MM cell line U-266-1970 constitutively expressing the active mutant Stat1C. We found that constitutive nuclear localization and transcriptional activity of Stat1 was associated with an attenuation of IL-6-induced Stat3 activation and up-regulation of mRNA for the pro-apoptotic Bcl-2 protein family genes Harakiri, the short form of Mcl-1 and Noxa. However, Stat1 activation alone was not sufficient to sensitize cells to Fas-induced apoptosis. In a screening of > 3000 compounds including bortezomib, dexamethasone, etoposide, suberoylanilide hydroxamic acid (SAHA, geldanamycin (17-AAG, doxorubicin and thalidomide, we found that the drug response and IC50 in cells constitutively expressing active Stat1 was mainly unaltered. Conclusion We conclude that Stat1 alters IL-6
Stat1 activation attenuates IL-6 induced Stat3 activity but does not alter apoptosis sensitivity in multiple myeloma

International Nuclear Information System (INIS)

Dimberg, Lina Y; Nilsson, Kenneth; Öberg, Fredrik; Wiklund, Helena Jernberg; Dimberg, Anna; Ivarsson, Karolina; Fryknäs, Mårten; Rickardson, Linda; Tobin, Gerard; Ekman, Simon; Larsson, Rolf; Gullberg, Urban

2012-01-01

Multiple myeloma (MM) is at present an incurable malignancy, characterized by apoptosis-resistant tumor cells. Interferon (IFN) treatment sensitizes MM cells to Fas-induced apoptosis and is associated with an increased activation of Signal transducer and activator of transcription (Stat)1. The role of Stat1 in MM has not been elucidated, but Stat1 has in several studies been ascribed a pro-apoptotic role. Conversely, IL-6 induction of Stat3 is known to confer resistance to apoptosis in MM. To delineate the role of Stat1 in IFN mediated sensitization to apoptosis, sub-lines of the U-266-1970 MM cell line with a stable expression of the active mutant Stat1C were utilized. The influence of Stat1C constitutive transcriptional activation on endogenous Stat3 expression and activation, and the expression of apoptosis-related genes were analyzed. To determine whether Stat1 alone would be an important determinant in sensitizing MM cells to apoptosis, the U-266-1970-Stat1C cell line and control cells were exposed to high throughput compound screening (HTS). To explore the role of Stat1 in IFN mediated apoptosis sensitization of MM, we established sublines of the MM cell line U-266-1970 constitutively expressing the active mutant Stat1C. We found that constitutive nuclear localization and transcriptional activity of Stat1 was associated with an attenuation of IL-6-induced Stat3 activation and up-regulation of mRNA for the pro-apoptotic Bcl-2 protein family genes Harakiri, the short form of Mcl-1 and Noxa. However, Stat1 activation alone was not sufficient to sensitize cells to Fas-induced apoptosis. In a screening of > 3000 compounds including bortezomib, dexamethasone, etoposide, suberoylanilide hydroxamic acid (SAHA), geldanamycin (17-AAG), doxorubicin and thalidomide, we found that the drug response and IC50 in cells constitutively expressing active Stat1 was mainly unaltered. We conclude that Stat1 alters IL-6 induced Stat3 activity and the expression of pro
Evaluation of the oxidative stress modulation in Drosophila melanogaster strains deficient in endogenous antioxidants and with chronic exposure to casiopeina Cas II-gly and gamma radiation

International Nuclear Information System (INIS)

Jimenez V, E. R.

2013-01-01

The casiopeinas are a family of coordination compounds with copper metallic center that have shown to have antineoplastic activity. The experimental evidences suggest that its action mechanism is through the generation of free radicals. The casiopeina (Cas II-gly) is believed to causes oxidative damage in the mitochondria, leading to the cellular death. The present study has the purpose to evaluate the antioxidant potential of the tetrapyrroles: cupro-sodica chlorophyllin (CSC), protoporphyrin-Ix (Pp-Ix) and the bilirubin (Bili) against the oxidant action of the Cas II-gly. The present study will also contribute in the characterization of the biological activity of the Cas II-gly. For this purpose is quantifies the effect of these compounds in the enzymes activity, superoxide dismutase (Sod) and catalase (Cat) in wild Drosophila melanogaster strains Canton-S and in the deficient in Sod and Cat. Two protocols were used, in the first male of 1-24 h of age were pre-treated with 0, 0.01, 0.1 and 1 m M of Cas II-gly and later on they were treated with radiation (15 Gy), and the second 69 m M of CSC, Pp-Ix or Bili, during 8 days and later they were treated with 0.1 m M of Cas II-gly during 24 h. The enzymatic activity was measured with the detection packages of enzymes Sod and Cat of Sigma. It was found that none of the three pigments increment the Sod activity but, if they diminished that of Cat (p≤0.007). The three concentrations of Cas II-gly did not increase the Sod activity significantly, only the concentration of 0.1 m M diminishes in 5.6 U the Cat activity (p <0.03) the same as the treatment with 15 Gy of gamma rays (8 U, p <0.004). The Cas II-gly combination 0.1 m M with the pigments does not modify the Sod and Cat activity. These results suggest that the proven pigments act as antioxidants, avoiding the induction of exogenous antioxidants caused by the gamma rays or the Cas II-gly. (Author)
Transcriptional regulation of the human Na+/H+ exchanger NHE3 by serotonin in intestinal epithelial cells

International Nuclear Information System (INIS)

Amin, Md Ruhul; Ghannad, Leda; Othman, Ahmad; Gill, Ravinder K.; Dudeja, Pradeep K.; Ramaswamy, Krishnamurthy; Malakooti, Jaleh

2009-01-01

Serotonin (5-HT) decreases NHE2 and NHE3 activities under acute conditions in human intestinal epithelial cells. Here, we have investigated the effects of 5-HT on expression of the human NHE3 gene and the mechanisms underlying its transcriptional regulation in differentiated C2BBe1 cells. Treatment of the human intestinal epithelial cell line, C2BBe1, with 5-HT (20 μM) resulted in a significant decrease in NHE3 mRNA and protein expression. In transient transfection studies, 5-HT repressed the NHE3 promoter activity by ∼55%. The repression of the NHE3 promoter activity in response to 5-HT was accompanied by reduced DNA-binding activity of transcription factors Sp1 and Sp3 to the NHE3 promoter without alteration in their nuclear levels. Pharmacological inhibitors of protein kinase C reversed the inhibitory effect of 5-HT on the promoter activity. Our data indicate that 5-HT suppresses the transcriptional activity of the NHE3 promoter and this effect may be mediated by PKCα and modulation of DNA-binding affinities of Sp1 and Sp3.
A hyperactive transcriptional state marks genome reactivation at the mitosis–G1 transition

Science.gov (United States)

Hsiung, Chris C.-S.; Bartman, Caroline R.; Huang, Peng; Ginart, Paul; Stonestrom, Aaron J.; Keller, Cheryl A.; Face, Carolyne; Jahn, Kristen S.; Evans, Perry; Sankaranarayanan, Laavanya; Giardine, Belinda; Hardison, Ross C.; Raj, Arjun; Blobel, Gerd A.

2016-01-01

During mitosis, RNA polymerase II (Pol II) and many transcription factors dissociate from chromatin, and transcription ceases globally. Transcription is known to restart in bulk by telophase, but whether de novo transcription at the mitosis–G1 transition is in any way distinct from later in interphase remains unknown. We tracked Pol II occupancy genome-wide in mammalian cells progressing from mitosis through late G1. Unexpectedly, during the earliest rounds of transcription at the mitosis–G1 transition, ∼50% of active genes and distal enhancers exhibit a spike in transcription, exceeding levels observed later in G1 phase. Enhancer–promoter chromatin contacts are depleted during mitosis and restored rapidly upon G1 entry but do not spike. Of the chromatin-associated features examined, histone H3 Lys27 acetylation levels at individual loci in mitosis best predict the mitosis–G1 transcriptional spike. Single-molecule RNA imaging supports that the mitosis–G1 transcriptional spike can constitute the maximum transcriptional activity per DNA copy throughout the cell division cycle. The transcriptional spike occurs heterogeneously and propagates to cell-to-cell differences in mature mRNA expression. Our results raise the possibility that passage through the mitosis–G1 transition might predispose cells to diverge in gene expression states. PMID:27340175
Arabidopsis Pol II-Dependent in Vitro Transcription System Reveals Role of Chromatin for Light-Inducible rbcS Gene Transcription1

Science.gov (United States)

Ido, Ayaka; Iwata, Shinya; Iwata, Yuka; Igarashi, Hisako; Hamada, Takahiro; Sonobe, Seiji; Sugiura, Masahiro; Yukawa, Yasushi

2016-01-01

In vitro transcription is an essential tool to study the molecular mechanisms of transcription. For over a decade, we have developed an in vitro transcription system from tobacco (Nicotiana tabacum)-cultured cells (BY-2), and this system supported the basic activities of the three RNA polymerases (Pol I, Pol II, and Pol III). However, it was not suitable to study photosynthetic genes, because BY-2 cells have lost their photosynthetic activity. Therefore, Arabidopsis (Arabidopsis thaliana) in vitro transcription systems were developed from green and etiolated suspension cells. Sufficient in vitro Pol II activity was detected after the minor modification of the nuclear soluble extracts preparation method; removal of vacuoles from protoplasts and L-ascorbic acid supplementation in the extraction buffer were particularly effective. Surprisingly, all four Arabidopsis Rubisco small subunit (rbcS-1A, rbcS-1B, rbcS-2B, and rbcS-3B) gene members were in vitro transcribed from the naked DNA templates without any light-dependent manner. However, clear light-inducible transcriptions were observed using chromatin template of rbcS-1A gene, which was prepared with a human nucleosome assembly protein 1 (hNAP1) and HeLa histones. This suggested that a key determinant of light-dependency through the rbcS gene transcription was a higher order of DNA structure (i.e. chromatin). PMID:26662274
Arg156 in the AP2-domain exhibits the highest binding activity among the 20 individuals to the GCC box in BnaERF-B3-hy15, a mutant ERF transcription factor from Brassica napus

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Jing Zhuang

2016-10-01

Full Text Available To develop mutants of the ERF factor with more binding activities to the GCC box, we performed in vitro directed evolution by using DNA shuffling and screened mutants through yeast one-hybrid assay. Here, a series of mutants were obtained and used to reveal key amino acids that induce changes in the DNA binding activity of the BnaERF-B3 protein. With the BnaERF-B3-hy15 as the template, we produced 12 mutants which host individual mutation of potential key residues. We found that amino acid 156 is the key site, and the other 18 mutants host the 18 corresponding individual amino acid residues at site 156. Among the 20 individuals comprising WT (Gly156, Mu3 (Arg156, and 18 mutants with other 18 amino acid residues, Arg156 in the AP2-domain is the amino acid residue with the highest binding activity to the GCC box. The structure of the α-helix in the AP2-domain affects the binding activity. Other residues within AP2-domain modulated binding activity of ERF protein, suggesting that these positions are important for binding activity. Comparison of the mutant and wild-type transcription factors revealed the relationship of protein function and sequence modification. Our result provides a potential useful resource for understanding the trans-activation of ERF proteins.
Arsenic inhibits hedgehog signaling during P19 cell differentiation

Energy Technology Data Exchange (ETDEWEB)

Liu, Jui Tung [Environmental Toxicology Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Bain, Lisa J., E-mail: lbain@clemson.edu [Environmental Toxicology Program, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States); Department of Biological Sciences, Clemson University, 132 Long Hall, Clemson, SC 29634 (United States)

2014-12-15

Arsenic is a toxicant found in ground water around the world, and human exposure mainly comes from drinking water or from crops grown in areas containing arsenic in soils or water. Epidemiological studies have shown that arsenic exposure during development decreased intellectual function, reduced birth weight, and altered locomotor activity, while in vitro studies have shown that arsenite decreased muscle and neuronal cell differentiation. The sonic hedgehog (Shh) signaling pathway plays an important role during the differentiation of both neurons and skeletal muscle. The purpose of this study was to investigate whether arsenic can disrupt Shh signaling in P19 mouse embryonic stem cells, leading to changes muscle and neuronal cell differentiation. P19 embryonic stem cells were exposed to 0, 0.25, or 0.5 μM of sodium arsenite for up to 9 days during cell differentiation. We found that arsenite exposure significantly reduced transcript levels of genes in the Shh pathway in both a time and dose-dependent manner. This included the Shh ligand, which was decreased 2- to 3-fold, the Gli2 transcription factor, which was decreased 2- to 3-fold, and its downstream target gene Ascl1, which was decreased 5-fold. GLI2 protein levels and transcriptional activity were also reduced. However, arsenic did not alter GLI2 primary cilium accumulation or nuclear translocation. Moreover, additional extracellular SHH rescued the inhibitory effects of arsenic on cellular differentiation due to an increase in GLI binding activity. Taken together, we conclude that arsenic exposure affected Shh signaling, ultimately decreasing the expression of the Gli2 transcription factor. These results suggest a mechanism by which arsenic disrupts cell differentiation. - Highlights: • Arsenic exposure decreases sonic hedgehog pathway-related gene expression. • Arsenic decreases GLI2 protein levels and transcriptional activity in P19 cells. • Arsenic exposure does not alter the levels of SHH
PEA3/ETV4-related transcription factors coupled with active ERK signalling are associated with poor prognosis in gastric adenocarcinoma

LENUS (Irish Health Repository)

Keld, R

2011-06-28

Background: Transcription factors often play important roles in tumourigenesis. Members of the PEA3 subfamily of ETS-domain transcription factors fulfil such a role and have been associated with tumour metastasis in several different cancers. Moreover, the activity of the PEA3 subfamily transcription factors is potentiated by Ras-ERK pathway signalling, which is itself often deregulated in tumour cells.\\r\
Time-dependent, bidirectional, anti- and pro-spinal hyper-reflexia and muscle spasticity effect after chronic spinal glycine transporter 2 (GlyT2) oligonucleotide-induced downregulation.

Science.gov (United States)

Kamizato, Kota; Marsala, Silvia; Navarro, Michael; Kakinohana, Manabu; Platoshyn, Oleksandr; Yoshizumi, Tetsuya; Lukacova, Nadezda; Wancewicz, Ed; Powers, Berit; Mazur, Curt; Marsala, Martin

2018-07-01

The loss of local spinal glycine-ergic tone has been postulated as one of the mechanisms contributing to the development of spinal injury-induced spasticity. In our present study using a model of spinal transection-induced muscle spasticity, we characterize the effect of spinally-targeted GlyT2 downregulation once initiated at chronic stages after induction of spasticity in rats. In animals with identified hyper-reflexia, the anti-spasticity effect was studied after intrathecal treatment with: i) glycine, ii) GlyT2 inhibitor (ALX 1393), and iii) GlyT2 antisense oligonucleotide (GlyT2-ASO). Administration of glycine and GlyT2 inhibitor led to significant suppression of spasticity lasting for a minimum of 45-60 min. Treatment with GlyT2-ASO led to progressive suppression of muscle spasticity seen at 2-3 weeks after treatment. Over the subsequent 4-12 weeks, however, the gradual appearance of profound spinal hyper-reflexia was seen. This was presented as spontaneous or slight-tactile stimulus-evoked muscle oscillations in the hind limbs (but not in upper limbs) with individual hyper-reflexive episodes lasting between 3 and 5 min. Chronic hyper-reflexia induced by GlyT2-ASO treatment was effectively blocked by intrathecal glycine. Immunofluorescence staining and Q-PCR analysis of the lumbar spinal cord region showed a significant (>90%) decrease in GlyT2 mRNA and GlyT2 protein. These data demonstrate that spinal GlyT2 downregulation provides only a time-limited therapeutic benefit and that subsequent loss of glycine vesicular synthesis resulting from chronic GlyT2 downregulation near completely eliminates the tonic glycine-ergic activity and is functionally expressed as profound spinal hyper-reflexia. These characteristics also suggest that chronic spinal GlyT2 silencing may be associated with pro-nociceptive activity. Copyright © 2018 Elsevier Inc. All rights reserved.
Inhibition of Notch1 promotes hedgehog signalling in a HES1-dependent manner in chondrocytes and exacerbates experimental osteoarthritis.

Science.gov (United States)

Lin, Neng-Yu; Distler, Alfiya; Beyer, Christian; Philipi-Schöbinger, Ariella; Breda, Silvia; Dees, Clara; Stock, Michael; Tomcik, Michal; Niemeier, Andreas; Dell'Accio, Francesco; Gelse, Kolja; Mattson, Mark P; Schett, Georg; Distler, Jörg Hw

2016-11-01

Notch ligands and receptors have recently been shown to be differentially expressed in osteoarthritis (OA). We aim to further elucidate the functional role of Notch signalling in OA using Notch1 antisense transgenic (Notch1 AS) mice. Notch and hedgehog signalling were analysed by real-time PCR and immunohistochemistry. Notch-1 AS mice were employed as a model of impaired Notch signalling in vivo. Experimental OA was induced by destabilisation of the medial meniscus (DMM). The extent of cartilage destruction and osteophyte formation was analysed by safranin-O staining with subsequent assessment of the Osteoarthritis Research Society International (OARSI) and Mankin scores and µCT scanning. Collagen X staining was used as a marker of chondrocyte hypertrophy. The role of hairy/enhancer of split 1 (Hes-1) was investigated with knockdown and overexpression experiments. Notch signalling was activated in human and murine OA with increased expression of Jagged1, Notch-1, accumulation of the Notch intracellular domain 1 and increased transcription of Hes-1. Notch1 AS mice showed exacerbated OA with increases in OARSI scores, osteophyte formation, increased subchondral bone plate density, collagen X and osteocalcin expression and elevated levels of Epas1 and ADAM-TS5 mRNA. Inhibition of the Notch pathway induced activation of hedgehog signalling with induction of Gli-1 and Gli-2 and increased transcription of hedgehog target genes. The regulatory effects of Notch signalling on Gli-expression were mimicked by Hes-1. Inhibition of Notch signalling activates hedgehog signalling, enhances chondrocyte hypertrophy and exacerbates experimental OA including osteophyte formation. These data suggest that the activation of the Notch pathway may limit aberrant hedgehog signalling in OA. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Diffusion-weighted magnetic resonance imaging reflects activation of signal transducer and activator of transcription 3 during focal cerebral ischemia/reperfusion

Directory of Open Access Journals (Sweden)

Wen-juan Wu

2017-01-01

Full Text Available Signal transducer and activator of transcription (STAT is a unique protein family that binds to DNA, coupled with tyrosine phosphorylation signaling pathways, acting as a transcriptional regulator to mediate a variety of biological effects. Cerebral ischemia and reperfusion can activate STATs signaling pathway, but no studies have confirmed whether STAT activation can be verified by diffusion-weighted magnetic resonance imaging (DWI in rats after cerebral ischemia/reperfusion. Here, we established a rat model of focal cerebral ischemia injury using the modified Longa method. DWI revealed hyperintensity in parts of the left hemisphere before reperfusion and a low apparent diffusion coefficient. STAT3 protein expression showed no significant change after reperfusion, but phosphorylated STAT3 expression began to increase after 30 minutes of reperfusion and peaked at 24 hours. Pearson correlation analysis showed that STAT3 activation was correlated positively with the relative apparent diffusion coefficient and negatively with the DWI abnormal signal area. These results indicate that DWI is a reliable representation of the infarct area and reflects STAT phosphorylation in rat brain following focal cerebral ischemia/reperfusion.
C/EBPβ contributes to transcriptional activation of long non-coding RNA NEAT1 during APL cell differentiation.

Science.gov (United States)

Wang, Yewei; Fu, Lei; Sun, Ailian; Tang, Doudou; Xu, Yunxiao; Li, Zheyuan; Chen, Mingjie; Zhang, Guangsen

2018-05-05

Emerging evidences have shown that long non-coding RNAs (lncRNAs) play critical roles in cancer development and cancer therapy. LncRNA Nuclear Enriched Abundant Transcript 1 (NEAT1) is indispensable during acute promyelocytic leukemia (APL) cell differentiation induced by all-trans retinoic acid (ATRA). However, the precise mechanism of NEAT1 upregulation has not been fully understood. In this study, we performed chromatin immunoprecipitation and luciferase reporter assays to demonstrate that C/EBP family transcription factor C/EBPβ bind to and transactivate the promoter of lncRNA NEAT1 through the C/EBPβ binding sites both around -54 bp and -1453 bp upstream of the transcription start site. Moreover, the expression of C/EBPβ was increased after ATRA treatment, and the binding of C/EBPβ in the NEAT1 promoter was also dramatically increased. Finally, knockdown of C/EBPβ significantly reduced the ATRA-induced upregulation of NEAT1. In conclusion, C/EBPβ directly activates the expression of NEAT1 through binding to the promoter of NEAT1. Knockdown of C/EBPβ impairs ATRA-induced transcriptional activation of NEAT1. Our data indicate that C/EBPβ contributes to ATRA-induced activation of NEAT1 during APL cell differentiation. Our results enrich our knowledge on the regulation of lncRNAs and the regulatory role of C/EBPβ in APL cell differentiation. Copyright © 2017. Published by Elsevier Inc.
Identification of a novel herpes simplex virus type 1 transcript and protein (AL3) expressed during latency.

Science.gov (United States)

Jaber, Tareq; Henderson, Gail; Li, Sumin; Perng, Guey-Chuen; Carpenter, Dale; Wechsler, Steven L; Jones, Clinton

2009-10-01

The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected sensory neurons. In small animal models of infection, expression of the first 1.5 kb of LAT coding sequences is necessary and sufficient for wild-type reactivation from latency. The ability of LAT to inhibit apoptosis is important for reactivation from latency. Within the first 1.5 kb of LAT coding sequences and LAT promoter sequences, additional transcripts have been identified. For example, the anti-sense to LAT transcript (AL) is expressed in the opposite direction to LAT from the 5' end of LAT and LAT promoter sequences. In addition, the upstream of LAT (UOL) transcript is expressed in the LAT direction from sequences in the LAT promoter. Further examination of the first 1.5 kb of LAT coding sequences revealed two small ORFs that are anti-sense with respect to LAT (AL2 and AL3). A transcript spanning AL3 was detected in productively infected cells, mouse neuroblastoma cells stably expressing LAT and trigeminal ganglia (TG) of latently infected mice. Peptide-specific IgG directed against AL3 specifically recognized a protein migrating near 15 kDa in cells stably transfected with LAT, mouse neuroblastoma cells transfected with a plasmid containing the AL3 ORF and TG of latently infected mice. The inability to detect the AL3 protein during productive infection may have been because the 5' terminus of the AL3 transcript was downstream of the first in-frame methionine of the AL3 ORF during productive infection.
A Patient With a Mild Holoprosencephaly Spectrum Phenotype and Heterotaxy and a 1.3 Mb Deletion Encompassing GLI2

NARCIS (Netherlands)

Kevelam, S.H.G.; van Harssel, J.J.; van der Zwaag, B.; Smeets, H.J.; Paulussen, A.D.; Lichtenbelt, K.D.

2012-01-01

Loss-of-function mutations of GLI2 are associated with features at the mild end of the holoprosencephaly spectrum, including abnormal pituitary gland formation and/or function, and craniofacial abnormalities. In addition patients may have branchial arch anomalies and polydactyly. Large,
Improving Tumor Uptake and Pharmacokinetics of 64Cu-Labeled Cyclic RGD Peptide Dimers with Gly3 and PEG4 Linkers

OpenAIRE

Shi, Jiyun; Kim, Young-Seung; Zhai, Shizhen; Liu, Zhaofei; Chen, Xiaoyuan; Liu, Shuang

2009-01-01

Radiolabeled cyclic RGD (Arg-Gly-Asp) peptides represent a new class of radiotracers with potential for the early tumor detection and non-invasive monitoring of tumor metastasis and therapeutic response in cancer patients. This report describes the synthesis of two cyclic RGD peptide dimer conjugates, DOTA-PEG4-E[PEG4-c(RGDfK)]2 (DOTA-3PEG4-dimer: DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid; PEG4 = 15-amino-4,7,10,13-tetraoxapentadecanoic acid) and DOTA-G3-E[G3-c(RGDfK)]2 ...
The Mediator Complex MED15 Subunit Mediates Activation of Downstream Lipid-Related Genes by the WRINKLED1 Transcription Factor.

Science.gov (United States)

Kim, Mi Jung; Jang, In-Cheol; Chua, Nam-Hai

2016-07-01

The Mediator complex is known to be a master coordinator of transcription by RNA polymerase II, and this complex is recruited by transcription factors (TFs) to target promoters for gene activation or repression. The plant-specific TF WRINKLED1 (WRI1) activates glycolysis-related and fatty acid biosynthetic genes during embryogenesis. However, no Mediator subunit has yet been identified that mediates WRI1 transcriptional activity. Promoter-β-glucuronidase fusion experiments showed that MEDIATOR15 (MED15) is expressed in the same cells in the embryo as WRI1. We found that the Arabidopsis (Arabidopsis thaliana) MED15 subunit of the Mediator complex interacts directly with WRI1 in the nucleus. Overexpression of MED15 or WRI1 increased transcript levels of WRI1 target genes involved in glycolysis and fatty acid biosynthesis; these genes were down-regulated in wild-type or WRI1-overexpressing plants by silencing of MED15 However, overexpression of MED15 in the wri1 mutant also increased transcript levels of WRI1 target genes, suggesting that MED15 also may act with other TFs to activate downstream lipid-related genes. Chromatin immunoprecipitation assays confirmed the association of MED15 with six WRI1 target gene promoters. Additionally, silencing of MED15 resulted in reduced fatty acid content in seedlings and mature seeds, whereas MED15 overexpression increased fatty acid content in both developmental stages. Similar results were found in wri1 mutant and WRI1 overexpression lines. Together, our results indicate that the WRI1/MED15 complex transcriptionally regulates glycolysis-related and fatty acid biosynthetic genes during embryogenesis. © 2016 American Society of Plant Biologists. All Rights Reserved.
Resveratrol induces growth arrest and apoptosis through activation of FOXO transcription factors in prostate cancer cells.

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Qinghe Chen

2010-12-01

Full Text Available Resveratrol, a naturally occurring phytopolyphenol compound, has attracted extensive interest in recent years because of its diverse pharmacological characteristics. Although resveratrol possesses chemopreventive properties against several cancers, the molecular mechanisms by which it inhibits cell growth and induces apoptosis have not been clearly understood. The present study was carried out to examine whether PI3K/AKT/FOXO pathway mediates the biological effects of resveratrol.Resveratrol inhibited the phosphorylation of PI3K, AKT and mTOR. Resveratrol, PI3K inhibitors (LY294002 and Wortmannin and AKT inhibitor alone slightly induced apoptosis in LNCaP cells. These inhibitors further enhanced the apoptosis-inducing potential of resveratrol. Overexpression of wild-type PTEN slightly induced apoptosis. Wild type PTEN and PTEN-G129E enhanced resveratrol-induced apoptosis, whereas PTEN-G129R had no effect on proapoptotic effects of resveratrol. Furthermore, apoptosis-inducing potential of resveratrol was enhanced by dominant negative AKT, and inhibited by wild-type AKT and constitutively active AKT. Resveratrol has no effect on the expression of FKHR, FKHRL1 and AFX genes. The inhibition of FOXO phosphorylation by resveratrol resulted in its nuclear translocation, DNA binding and transcriptional activity. The inhibition of PI3K/AKT pathway induced FOXO transcriptional activity resulting in induction of Bim, TRAIL, p27/KIP1, DR4 and DR5, and inhibition of cyclin D1. Similarly, resveratrol-induced FOXO transcriptional activity was further enhanced when activation of PI3K/AKT pathway was blocked. Over-expression of phosphorylation deficient mutants of FOXO proteins (FOXO1-TM, FOXO3A-TM and FOXO4-TM induced FOXO transcriptional activity, which was further enhanced by resveratrol. Inhibition of FOXO transcription factors by shRNA blocked resveratrol-induced upregulation of Bim, TRAIL, DR4, DR5, p27/KIP1 and apoptosis, and inhibition of cyclin D1 by
Activation of the sonic hedgehog signaling pathway occurs in the CD133 positive cells of mouse liver cancer Hepa 1–6 cells

Directory of Open Access Journals (Sweden)

Jeng KS

2013-08-01

Full Text Available Kuo-Shyang Jeng,1 I-Shyan Sheen,2 Wen-Juei Jeng,2 Ming-Che Yu,3 Hsin-I Hsiau,3 Fang-Yu Chang,3 Hsin-Hua Tsai31Department of Surgery, Far Eastern Memorial Hospital, Taipei, 2Department of Hepato-Gastroenterology, Chang Gung Memorial Hospital, Linkou Medical Center, Chang Gung University, 3Department of Medical Research, Far Eastern Memorial Hospital, Taipei, Taiwan, Republic of ChinaBackground: The important role of cancer stem cells in carcinogenesis has been emphasized in research. CD133+ cells have been mentioned as liver cancer stem cells in hepatocellular carcinoma (HCC. Some researchers have proposed that the sonic hedgehog (Shh pathway contributes to hepatocarcinogenesis and that the pathway activation occurs mainly in cancer stem cells. We investigated whether the activation of the Shh pathway occurs in CD133+ cells from liver cancer.Materials and methods: We used magnetic sorting to isolate CD133+ cells from mouse cancer Hepa 1–6 cells. To examine the clonogenicity, cell culture and soft agar colony formation assay were performed between CD133+ and CD133- cells. To study the activation of the Shh pathway, we examined the mRNA expressions of Shh, patched homolog 1 (Ptch-1, glioma-associated oncogene homolog 1 (Gli-1, and smoothened homolog (Smoh by real-time polymerase chain reaction of both CD133+ and CD133- cells.Results: The number (mean ± standard deviation of colonies of CD133+ cells and CD133- cells was 1,031.0 ± 104.7 and 119.7 ± 17.6 respectively. This difference was statistically significant (P < 0.001. Their clonogenicity was 13.7% ± 1.4% and 1.6% ± 0.2% respectively with a statistically significant difference found (P < 0.001. CD133+ cells and CD133– cells were found to have statistically significant differences in Shh mRNA and Smoh mRNA (P = 0.005 and P = 0.043 respectively.Conclusion: CD133+ Hepa 1–6 cells have a significantly higher colony proliferation and clonogenicity. The Shh pathway is activated in these
Dopamine D3 receptor Ser9Gly variant is associated with impulse control disorders in Parkinson's disease patients.

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Krishnamoorthy, Soumya; Rajan, Roopa; Banerjee, Moinak; Kumar, Hardeep; Sarma, Gangadhara; Krishnan, Syam; Sarma, Sankara; Kishore, Asha

2016-09-01

Impulse control disorders (ICD) are reported to occur at variable frequencies in different ethnic groups. Genetic vulnerability is suspected to underlie the individual risk for ICD. We investigated whether the allelic variants of dopamine (DRD3), glutamate (GRIN2B) and serotonin (HTR2A) receptors are linked to ICD in Indian Parkinson's disease (PD) patients. We conducted a prospective, case-control study which included PD patients (70 with ICD, 100 without ICD categorized after direct psychiatric interview of patient and caregiver) and 285 healthy controls. Single nucleotide polymorphism (SNP) variants of DRD3 p.S9G (rs6280), GRIN2B c.2664C>T (rs1806201) and HTR2A c.102T>C (rs6313) were genotyped. Multivariate regression analysis revealed that DRD3 p.Ser9Gly (rs6280) heterozygous variant CT (OR = 2.22, 95% CI: 1.03-4.86, p = 0.041), higher daily Levodopa equivalent doses (LED) of drugs (for 100 mg LED, OR = 1.14, 95% CI: 1.01-1.29, p = 0.041), current dopamine agonist but not Levodopa use (OR = 2.16, 95% CI: 1.03-4.55, p = 0.042) and age of onset of motor symptoms under 50 years (OR 2.09, 95% CI: 1.05-4.18, p = 0.035) were independently associated with ICD. DRD3 p.Ser9Gly (rs6280) CT genotype is associated with ICD in Indian PD patients and this association is novel. Enhanced D3 receptor affinity due to gain-of-function conferred by the glycine residues could impair reward-risk assessment in the mesolimbic system and contribute to development of impulsive behaviour, in carriers of this genotype. Copyright © 2016. Published by Elsevier Ltd.
Tye7 regulates yeast Ty1 retrotransposon sense and antisense transcription in response to adenylic nucleotides stress.

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Servant, Géraldine; Pinson, Benoit; Tchalikian-Cosson, Aurélie; Coulpier, Fanny; Lemoine, Sophie; Pennetier, Carole; Bridier-Nahmias, Antoine; Todeschini, Anne Laure; Fayol, Hélène; Daignan-Fornier, Bertrand; Lesage, Pascale

2012-07-01

Transposable elements play a fundamental role in genome evolution. It is proposed that their mobility, activated under stress, induces mutations that could confer advantages to the host organism. Transcription of the Ty1 LTR-retrotransposon of Saccharomyces cerevisiae is activated in response to a severe deficiency in adenylic nucleotides. Here, we show that Ty2 and Ty3 are also stimulated under these stress conditions, revealing the simultaneous activation of three active Ty retrotransposon families. We demonstrate that Ty1 activation in response to adenylic nucleotide depletion requires the DNA-binding transcription factor Tye7. Ty1 is transcribed in both sense and antisense directions. We identify three Tye7 potential binding sites in the region of Ty1 DNA sequence where antisense transcription starts. We show that Tye7 binds to Ty1 DNA and regulates Ty1 antisense transcription. Altogether, our data suggest that, in response to adenylic nucleotide reduction, TYE7 is induced and activates Ty1 mRNA transcription, possibly by controlling Ty1 antisense transcription. We also provide the first evidence that Ty1 antisense transcription can be regulated by environmental stress conditions, pointing to a new level of control of Ty1 activity by stress, as Ty1 antisense RNAs play an important role in regulating Ty1 mobility at both the transcriptional and post-transcriptional stages.
The intracellular immune receptor Rx1 regulates the DNA-binding activity of a Golden2-like transcription factor.

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Townsend, Philip D; Dixon, Christopher H; Slootweg, Erik J; Sukarta, Octavina C A; Yang, Ally W H; Hughes, Timothy R; Sharples, Gary J; Pålsson, Lars-Olof; Takken, Frank L W; Goverse, Aska; Cann, Martin J

2018-03-02

Plant nucleotide-binding leucine-rich repeat (NLR) proteins enable the immune system to recognize and respond to pathogen attack. An early consequence of immune activation is transcriptional reprogramming, and some NLRs have been shown to act in the nucleus and interact with transcription factors. The Rx1 NLR protein of potato is further able to bind and distort double-stranded DNA. However, Rx1 host targets that support a role for Rx1 in transcriptional reprogramming at DNA are unknown. Here, we report a functional interaction between Rx1 and Nb Glk1, a Golden2-like transcription factor. Rx1 binds to Nb Glk1 in vitro and in planta. Nb Glk1 binds to known Golden2-like consensus DNA sequences. Rx1 reduces the binding affinity of Nb Glk1 for DNA in vitro. Nb Glk1 activates cellular responses to potato virus X, whereas Rx1 associates with Nb Glk1 and prevents its assembly on DNA in planta unless activated by PVX. This study provides new mechanistic insight into how an NLR can coordinate an immune signaling response at DNA following pathogen perceptions. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.
Transient Receptor Potential Vanilloid 4 Activation-Induced Increase in Glycine-Activated Current in Mouse Hippocampal Pyramidal Neurons

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Mengwen Qi

2018-02-01

Full Text Available Background/Aims: Glycine plays an important role in regulating hippocampal inhibitory/ excitatory neurotransmission through activating glycine receptors (GlyRs and acting as a co-agonist of N-methyl-d-aspartate-type glutamate receptors. Activation of transient receptor potential vanilloid 4 (TRPV4 is reported to inhibit hippocampal A-type γ-aminobutyric acid receptor, a ligand-gated chloride ion channel. GlyRs are also ligand-gated chloride ion channels and this paper aimed to explore whether activation of TRPV4 could modulate GlyRs. Methods: Whole-cell patch clamp recording was employed to record glycine-activated current (IGly and Western blot was conducted to assess GlyRs subunits protein expression. Results: Application of TRPV4 agonist (GSK1016790A or 5,6-EET increased IGly in mouse hippocampal CA1 pyramidal neurons. This action was blocked by specific antagonists of TRPV4 (RN-1734 or HC-067047 and GlyR (strychnine, indicating that activation of TRPV4 increases strychnine-sensitive GlyR function in mouse hippocampal pyramidal neurons. GSK1016790A-induced increase in IGly was significantly attenuated by protein kinase C (PKC (BIM II or D-sphingosine or calcium/calmodulin-dependent protein kinase II (CaMKII (KN-62 or KN-93 antagonists but was unaffected by protein kinase A or protein tyrosine kinase antagonists. Finally, hippocampal protein levels of GlyR α1 α2, α3 and β subunits were not changed by treatment with GSK1016790A for 30 min or 1 h, but GlyR α2, α3 and β subunits protein levels increased in mice that were intracerebroventricularly (icv. injected with GSK1016790A for 5 d. Conclusion: Activation of TRPV4 increases GlyR function and expression, and PKC and CaMKII signaling pathways are involved in TRPV4 activation-induced increase in IGly. This study indicates that GlyRs may be effective targets for TRPV4-induced modulation of hippocampal inhibitory neurotransmission.
The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

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Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Facultad de Ciencias Quimicas y Farmaceuticas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Hidalgo, Cecilia [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Lavandero, Sergio, E-mail: slavander@uchile.cl [Centro FONDAP Estudios Moleculares de la Celula, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Facultad de Ciencias Quimicas y Farmaceuticas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile); Instituto de Ciencias Biomedicas, Facultad de Medicina, Universidad de Chile, Santiago 8380492 (Chile)

2009-10-09

Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal {alpha}-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.
The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

International Nuclear Information System (INIS)

Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo; Hidalgo, Cecilia; Lavandero, Sergio

2009-01-01

Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal α-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.
Modulatory role of phospholipase D in the activation of signal transducer and activator of transcription (STAT-3 by thyroid oncogenic kinase RET/PTC

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Kim Dong Wook

2008-05-01

Full Text Available Abstract Background RET/PTC (rearranged in transformation/papillary thyroid carcinomas gene rearrangements are the most frequent genetic alterations identified in papillary thyroid carcinoma. Although it has been established that RET/PTC kinase plays a crucial role in intracellular signaling pathways that regulate cellular transformation, growth, and proliferation in thyroid epithelial cells, the upstream signaling that leads to the activation of RET/PTC is largely unknown. Based on the observation of high levels of PLD expression in human papillary thyroid cancer tissues, we investigated whether PLD plays a role in the regulating the RET/PTC-induced STAT3 activation. Methods Cancer tissue samples were obtained from papillary thyroid cancer patients (n = 6. The expression level of PLD was examined using immunohistochemistry and western blotting. Direct interaction between RET/PTC and PLD was analyzed by co-immunoprecipitation assay. PLD activity was assessed by measuring the formation of [3H]phosphatidylbutanol, the product of PLD-mediated transphosphatidylation, in the presence of n-butanol. The transcriptional activity of STAT3 was assessed by m67 luciferase reporter assay. Results In human papillary thyroid cancer, the expression levels of PLD2 protein were higher than those in the corresponding paired normal tissues. PLD and RET/PTC could be co-immunoprecipitated from cells where each protein was over-expressed. In addition, the activation of PLD by pervanadate triggered phosphorylation of tyrosine 705 residue on STAT-3, and its phosphorylation was dramatically higher in TPC-1 cells (from papillary carcinoma that have an endogenous RET/PTC1 than in ARO cells (from anaplastic carcinoma without alteration of total STAT-3 expression. Moreover, the RET/PTC-mediated transcriptional activation of STAT-3 was synergistically increased by over-expression of PLD, whereas the PLD activity as a lipid hydrolyzing enzyme was not affected by RET
ZNF328, a novel human zinc-finger protein, suppresses transcriptional activities of SRE and AP-1

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Ou Ying; Wang Shenqiu; Cai Zhenyu; Wang Yuequn; Wang Canding; Li Yongqing; Li Fang; Yuan Wuzhou; Liu Bisheng; Wu Xiushan; Liu Mingyao

2005-01-01

The zinc finger proteins containing the Kruppel-associated box domain (KRAB-ZFPs) are the single largest class of transcription factors in human genome. Many of the KRAB-ZFPs are involved in cardiac development or cardiovascular diseases. Here, we have identified a novel human KRAB zinc finger gene, named ZNF328, from the human fetal heart cDNA library. The complete sequence of ZNF328 cDNA contains a 2376-bp open reading frame (ORF) and encodes a 792 amino acid protein with an N-terminal KRAB domain and classical zinc finger C 2 H 2 motifs in the C-terminus. Northern blot analysis indicates that the protein is expressed in most of the examined human adult and embryonic tissues. ZNF328 is a transcription suppressor when fused to Gal-4 DNA-binding domain and cotransfected with VP-16. Overexpression of ZNF328 in COS-7 cells inhibits the transcriptional activities of SRE and AP-1. Deletion analysis with a series of truncated fusion proteins indicates that the KRAB motif is a basal repression domain when cotransfected with VP-16. Similar results were obtained when the truncated fusion proteins were assayed for the transcriptional activities of SRE and AP-1. These results suggest that ZNF328 protein may act as a transcriptional repressor in mitogen-activated protein kinase (MAPK) signaling pathway to mediate cellular functions
A hyperactive transcriptional state marks genome reactivation at the mitosis-G1 transition.

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Hsiung, Chris C-S; Bartman, Caroline R; Huang, Peng; Ginart, Paul; Stonestrom, Aaron J; Keller, Cheryl A; Face, Carolyne; Jahn, Kristen S; Evans, Perry; Sankaranarayanan, Laavanya; Giardine, Belinda; Hardison, Ross C; Raj, Arjun; Blobel, Gerd A

2016-06-15

During mitosis, RNA polymerase II (Pol II) and many transcription factors dissociate from chromatin, and transcription ceases globally. Transcription is known to restart in bulk by telophase, but whether de novo transcription at the mitosis-G1 transition is in any way distinct from later in interphase remains unknown. We tracked Pol II occupancy genome-wide in mammalian cells progressing from mitosis through late G1. Unexpectedly, during the earliest rounds of transcription at the mitosis-G1 transition, ∼50% of active genes and distal enhancers exhibit a spike in transcription, exceeding levels observed later in G1 phase. Enhancer-promoter chromatin contacts are depleted during mitosis and restored rapidly upon G1 entry but do not spike. Of the chromatin-associated features examined, histone H3 Lys27 acetylation levels at individual loci in mitosis best predict the mitosis-G1 transcriptional spike. Single-molecule RNA imaging supports that the mitosis-G1 transcriptional spike can constitute the maximum transcriptional activity per DNA copy throughout the cell division cycle. The transcriptional spike occurs heterogeneously and propagates to cell-to-cell differences in mature mRNA expression. Our results raise the possibility that passage through the mitosis-G1 transition might predispose cells to diverge in gene expression states. © 2016 Hsiung et al.; Published by Cold Spring Harbor Laboratory Press.
The RNA helicase Rm62 cooperates with SU(VAR3-9 to re-silence active transcription in Drosophila melanogaster.

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Joern Boeke

Full Text Available Gene expression is highly dynamic and many genes show a wide range in expression over several orders of magnitude. This regulation is often mediated by sequence specific transcription factors. In addition, the tight packaging of DNA into chromatin can provide an additional layer of control resulting in a dynamic range of gene expression covering several orders of magnitude. During transcriptional activation, chromatin barriers have to be eliminated to allow an efficient progression of the RNA polymerase. This repressive chromatin structure has to be re-established quickly after it has been activated in order to tightly regulate gene activity. We show that the DExD/H box containing RNA helicase Rm62 is targeted to a site of rapid induction of transcription where it is responsible for an increased degree of methylation at H3K9 at the heat shock locus after removal of the heat shock stimulus. The RNA helicase interacts with the well-characterized histone methyltransferase SU(VAR3-9 via its N-terminus, which provides a potential mechanism for the targeting of H3K9 methylation to highly regulated genes. The recruitment of SU(VAR3-9 through interaction with a RNA helicase to a site of active transcription might be a general mechanism that allows an efficient silencing of highly regulated genes thereby enabling a cell to fine tune its gene activity over a wide range.
Mitotic Transcriptional Activation: Clearance of Actively Engaged Pol II via Transcriptional Elongation Control in Mitosis.

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Liang, Kaiwei; Woodfin, Ashley R; Slaughter, Brian D; Unruh, Jay R; Box, Andrew C; Rickels, Ryan A; Gao, Xin; Haug, Jeffrey S; Jaspersen, Sue L; Shilatifard, Ali

2015-11-05

Although it is established that some general transcription factors are inactivated at mitosis, many details of mitotic transcription inhibition (MTI) and its underlying mechanisms are largely unknown. We have identified mitotic transcriptional activation (MTA) as a key regulatory step to control transcription in mitosis for genes with transcriptionally engaged RNA polymerase II (Pol II) to activate and transcribe until the end of the gene to clear Pol II from mitotic chromatin, followed by global impairment of transcription reinitiation through MTI. Global nascent RNA sequencing and RNA fluorescence in situ hybridization demonstrate the existence of transcriptionally engaged Pol II in early mitosis. Both genetic and chemical inhibition of P-TEFb in mitosis lead to delays in the progression of cell division. Together, our study reveals a mechanism for MTA and MTI whereby transcriptionally engaged Pol II can progress into productive elongation and finish transcription to allow proper cellular division. Copyright © 2015 Elsevier Inc. All rights reserved.
Competitive Promoter-Associated Matrix Attachment Region Binding of the Arid3a and Cux1 Transcription Factors

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Dongkyoon Kim

2017-12-01

Full Text Available Arid3a/Bright/Dril1 is a B cell-specific transactivator that regulates immunoglobulin heavy chain (IgH gene transcription by binding promoter and enhancer-associated matrix attachment regions (MARs within the IgH gene locus. Promoter MAR-mediated Arid3a transactivation is antagonized by direct competition of MAR binding by Cux1/CDP—a ubiquitously expressed repressor originally termed NF-μNR. We report that the NF-μNR complex includes Arid3a in B cells but not in non-B cells through mobility shift assays. The binding activity of NF-μNR and Arid3a in B cells is reciprocally altered during the cell division cycle and by the B cell mitogen lipopolysaccharide LPS. LPS treatment had no effect on Arid3a localization but increased its total abundance within the nucleus and cytoplasm. We show that this increased level of Arid3a is capable of displacing Cux from the MARs to facilitate IgH gene transcription. Finally, we showed that the MARs (termed Bf150 and Tx125 associated with the VH1 rearranged variable region expressed in the S107 murine plasmacytoma, can repress reporter gene transcription in non-B cells and that they can relieve the repression mediated by Eμ enhancer in B cells. These results have significant implications for early human development and demonstrate that MARs in IgH locus, NF-µNR and Arid3a regulate IgH gene expression in a concerted fashion. This paves the way for future studies examining the misregulation of this pathway in pediatric disease.

DREAM Controls the On/Off Switch of Specific Activity-Dependent Transcription Pathways

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Mellström, Britt; Sahún, Ignasi; Ruiz-Nuño, Ana; Murtra, Patricia; Gomez-Villafuertes, Rosa; Savignac, Magali; Oliveros, Juan C.; Gonzalez, Paz; Kastanauskaite, Asta; Knafo, Shira; Zhuo, Min; Higuera-Matas, Alejandro; Errington, Michael L.; Maldonado, Rafael; DeFelipe, Javier; Jefferys, John G. R.; Bliss, Tim V. P.; Dierssen, Mara

2014-01-01

Changes in nuclear Ca2+ homeostasis activate specific gene expression programs and are central to the acquisition and storage of information in the brain. DREAM (downstream regulatory element antagonist modulator), also known as calsenilin/KChIP-3 (K+ channel interacting protein 3), is a Ca2+-binding protein that binds DNA and represses transcription in a Ca2+-dependent manner. To study the function of DREAM in the brain, we used transgenic mice expressing a Ca2+-insensitive/CREB-independent dominant active mutant DREAM (daDREAM). Using genome-wide analysis, we show that DREAM regulates the expression of specific activity-dependent transcription factors in the hippocampus, including Npas4, Nr4a1, Mef2c, JunB, and c-Fos. Furthermore, DREAM regulates its own expression, establishing an autoinhibitory feedback loop to terminate activity-dependent transcription. Ablation of DREAM does not modify activity-dependent transcription because of gene compensation by the other KChIP family members. The expression of daDREAM in the forebrain resulted in a complex phenotype characterized by loss of recurrent inhibition and enhanced long-term potentiation (LTP) in the dentate gyrus and impaired learning and memory. Our results indicate that DREAM is a major master switch transcription factor that regulates the on/off status of specific activity-dependent gene expression programs that control synaptic plasticity, learning, and memory. PMID:24366545
Peroxisome proliferator-activated receptor gamma recruits the positive transcription elongation factor b complex to activate transcription and promote adipogenesis

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Iankova, Irena; Petersen, Rasmus K; Annicotte, Jean-Sébastien

2006-01-01

Positive transcription elongation factor b (P-TEFb) phosphorylates the C-terminal domain of RNA polymerase II, facilitating transcriptional elongation. In addition to its participation in general transcription, P-TEFb is recruited to specific promoters by some transcription factors such as c......-Myc or MyoD. The P-TEFb complex is composed of a cyclin-dependent kinase (cdk9) subunit and a regulatory partner (cyclin T1, cyclin T2, or cyclin K). Because cdk9 has been shown to participate in differentiation processes, such as muscle cell differentiation, we studied a possible role of cdk9...... with and phosphorylation of peroxisome proliferator-activated receptor gamma (PPARgamma), which is the master regulator of this process, on the promoter of PPARgamma target genes. PPARgamma-cdk9 interaction results in increased transcriptional activity of PPARgamma and therefore increased adipogenesis....
Transcriptional co-activator PGC-1 alpha drives the formation of slow-twitch muscle fibres.

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Lin, Jiandie; Wu, Hai; Tarr, Paul T; Zhang, Chen-Yu; Wu, Zhidan; Boss, Olivier; Michael, Laura F; Puigserver, Pere; Isotani, Eiji; Olson, Eric N; Lowell, Bradford B; Bassel-Duby, Rhonda; Spiegelman, Bruce M

2002-08-15

The biochemical basis for the regulation of fibre-type determination in skeletal muscle is not well understood. In addition to the expression of particular myofibrillar proteins, type I (slow-twitch) fibres are much higher in mitochondrial content and are more dependent on oxidative metabolism than type II (fast-twitch) fibres. We have previously identified a transcriptional co-activator, peroxisome-proliferator-activated receptor-gamma co-activator-1 (PGC-1 alpha), which is expressed in several tissues including brown fat and skeletal muscle, and that activates mitochondrial biogenesis and oxidative metabolism. We show here that PGC-1 alpha is expressed preferentially in muscle enriched in type I fibres. When PGC-1 alpha is expressed at physiological levels in transgenic mice driven by a muscle creatine kinase (MCK) promoter, a fibre type conversion is observed: muscles normally rich in type II fibres are redder and activate genes of mitochondrial oxidative metabolism. Notably, putative type II muscles from PGC-1 alpha transgenic mice also express proteins characteristic of type I fibres, such as troponin I (slow) and myoglobin, and show a much greater resistance to electrically stimulated fatigue. Using fibre-type-specific promoters, we show in cultured muscle cells that PGC-1 alpha activates transcription in cooperation with Mef2 proteins and serves as a target for calcineurin signalling, which has been implicated in slow fibre gene expression. These data indicate that PGC-1 alpha is a principal factor regulating muscle fibre type determination.
Comparative proteomic analyses reveal that FlbA down-regulates gliT expression and SOD activity in Aspergillus fumigatus.

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Shin, Kwang-Soo; Park, Hee-Soo; Kim, Young-Hwan; Yu, Jae-Hyuk

2013-07-11

FlbA is a regulator of G-protein signaling protein that plays a central role in attenuating heterotrimeric G-protein mediated vegetative growth signaling in Aspergillus. The deletion of flbA (∆flbA) in the opportunistic human pathogen Aspergillus fumigatus results in accelerated cell death and autolysis in submerged culture. To further investigate the effects of ∆flbA on intracellular protein levels we carried out 2-D proteome analyses of 2-day old submerged cultures of ∆flbA and wild type (WT) strains and observed 160 differentially expressed proteins. Via nano-LC-ESI-MS/MS analyses, we revealed the identity of 10 and 2 proteins exhibiting high and low level accumulation, respectively, in ∆flbA strain. Notably, the GliT protein is accumulated at about 1800-fold higher levels in ∆flbA than WT. Moreover, GliT is secreted at high levels from ∆flbA strain, whereas Sod1 (superoxide dismutase) is secreted at a higher level in WT. Northern blot analyses reveal that ∆flbA results in elevated accumulation of gliT mRNA. Consequently, ∆flbA strain exhibits enhanced tolerance to gliotoxin toxicity. Finally, ∆flbA strain displayed enhanced SOD activity and elevated resistance to menadione and paraquat. In summary, FlbA-mediated signaling control negatively affects cellular responses associated with detoxification of reactive oxygen species and of exogenous gliotoxin in A. fumigatus. Regulator of G protein Signaling (RGS) proteins play crucial roles in fundamental biological processes in filamentous fungi. FlbA is the first studied filamentous fungal RGS protein, yet much remains to be understood about its roles in the opportunistic human pathogen Aspergillus fumigatus. In the present study, we examined the effects of the deletion of flbA using comprehensive analyses of the intra- and extracellular proteomes of A. fumigatus wild type and the flbA deletion mutant. Via MS analyses, we identified 10 proteins exhibiting high level accumulation in the flbA deletion
PPARγ activates ABCA1 gene transcription but reduces the level of ABCA1 protein in HepG2 cells

International Nuclear Information System (INIS)

Mogilenko, Denis A.; Shavva, Vladimir S.; Dizhe, Ella B.; Orlov, Sergey V.; Perevozchikov, Andrej P.

2010-01-01

Research highlights: → PPARγ activates ABCA1 gene expression but decreases ABCA1 protein content in human hepatoma cell line HepG2. → Treatment of HepG2 cells with PPARγ agonist GW1929 leads to dissociation of LXRβ from ABCA1-LXRβ complex. → Inhibition of protein kinases MEK1/2 abolishes PPARγ-mediated dissociation of LXRβ from ABCA1/LXRβ complex. → Activation of PPARγ leads to increasing of the level of LXRβ associated with LXRE within ABCA1 gene promoter. -- Abstract: Synthesis of ABCA1 protein in liver is necessary for high-density lipoproteins (HDL) formation in mammals. Nuclear receptor PPARγ is known as activator of ABCA1 expression, but details of PPARγ-mediated regulation of ABCA1 at both transcriptional and post-transcriptional levels in hepatocytes have not still been well elucidated. In this study we have shown, that PPARγ activates ABCA1 gene transcription in human hepatoma cells HepG2 through increasing of LXRβ binding with promoter region of ABCA1 gene. Treatment of HepG2 cells with PPARγ agonist GW1929 leads to dissociation of LXRβ from ABCA1/LXRβ complex and to nuclear translocation of this nuclear receptor resulting in reduction of ABCA1 protein level 24 h after treatment. Inhibition of protein kinases MEK1/2 abolishes PPARγ-mediated dissociation of LXRβ from ABCA1/LXRβ complex, but does not block PPARγ-dependent down-regulation of ABCA1 protein in HepG2 cells. These data suggest that PPARγ may be important for regulation of the level of hepatic ABCA1 protein and indicate the new interplays between PPARγ, LXRβ and MEK1/2 in regulation of ABCA1 mRNA and protein expression.
Lung Adenocarcinomas and Lung Cancer Cell Lines Show Association of MMP-1 Expression With STAT3 Activation

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Alexander Schütz

2015-04-01

Full Text Available Signal transducer and activator of transcription 3 (STAT3 is constitutively activated in the majority of lung cancer. This study aims at defining connections between STAT3 function and the malignant properties of non–small cell lung carcinoma (NSCLC cells. To address possible mechanisms by which STAT3 influences invasiveness, the expression of matrix metalloproteinase-1 (MMP-1 was analyzed and correlated with the STAT3 activity status. Studies on both surgical biopsies and on lung cancer cell lines revealed a coincidence of STAT3 activation and strong expression of MMP-1. MMP-1 and tyrosine-phosphorylated activated STAT3 were found co-localized in cancer tissues, most pronounced in tumor fronts, and in particular in adenocarcinomas. STAT3 activity was constitutive, although to different degrees, in the lung cancer cell lines investigated. Three cell lines (BEN, KNS62, and A549 were identified in which STAT3 activitation was inducible by Interleukin-6 (IL-6. In A549 cells, STAT3 activity enhanced the level of MMP-1 mRNA and stimulated transcription from the MMP-1 promoter in IL-6–stimulated A549 cells. STAT3 specificity of this effect was confirmed by STAT3 knockdown through RNA interference. Our results link aberrant activity of STAT3 in lung cancer cells to malignant tumor progression through up-regulation of expression of invasiveness-associated MMPs.
PDX1, Neurogenin-3, and MAFA: critical transcription regulators for beta cell development and regeneration

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Yaxi Zhu

2017-11-01

Full Text Available Abstract Transcription factors regulate gene expression through binding to specific enhancer sequences. Pancreas/duodenum homeobox protein 1 (PDX1, Neurogenin-3 (NEUROG3, and V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAFA are transcription factors critical for beta cell development and maturation. NEUROG3 is expressed in endocrine progenitor cells and controls islet differentiation and regeneration. PDX1 is essential for the development of pancreatic exocrine and endocrine cells including beta cells. PDX1 also binds to the regulatory elements and increases insulin gene transcription. Likewise, MAFA binds to the enhancer/promoter region of the insulin gene and drives insulin expression in response to glucose. In addition to those natural roles in beta cell development and maturation, ectopic expression of PDX1, NEUROG3, and/or MAFA has been successfully used to reprogram various cell types into insulin-producing cells in vitro and in vivo, such as pancreatic exocrine cells, hepatocytes, and pluripotent stem cells. Here, we review biological properties of PDX1, NEUROG3, and MAFA, and their applications and limitations for beta cell regenerative approaches. The primary source literature for this review was acquired using a PubMed search for articles published between 1990 and 2017. Search terms include diabetes, insulin, trans-differentiation, stem cells, and regenerative medicine.
Stat1-Vitamin D Receptor Interactions Antagonize 1,25-Dihydroxyvitamin D Transcriptional Activity and Enhance Stat1-Mediated Transcription

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Vidal, Marcos; Ramana, Chilakamarti V.; Dusso, Adriana S.

2002-01-01

The cytokine gamma interferon (IFN-γ) and the calcitropic steroid hormone 1,25-dihydroxyvitamin D (1,25D) are activators of macrophage immune function. In sarcoidosis, tuberculosis, and several granulomatoses, IFN-γ induces 1,25D synthesis by macrophages and inhibits 1,25D induction of 24-hydroxylase, a key enzyme in 1,25D inactivation, causing high levels of 1,25D in serum and hypercalcemia. This study delineates IFN-γ-1,25D cross talk in human monocytes-macrophages. Nuclear accumulation of Stat1 and vitamin D receptor (VDR) by IFN-γ and 1,25D promotes protein-protein interactions between Stat1 and the DNA binding domain of the VDR. This prevents VDR-retinoid X receptor (RXR) binding to the vitamin D-responsive element, thus diverting the VDR from its normal genomic target on the 24-hydroxylase promoter and antagonizing 1,25D-VDR transactivation of this gene. In contrast, 1,25D enhances IFN-γ action. Stat1-VDR interactions, by preventing Stat1 deactivation by tyrosine dephosphorylation, cooperate with IFN-γ/Stat1-induced transcription. This novel 1,25D-IFN-γ cross talk explains the pathogenesis of abnormal 1,25D homeostasis in granulomatous processes and provides new insights into 1,25D immunomodulatory properties. PMID:11909970
The functional DRD3 Ser9Gly polymorphism (rs6280) is pleiotropic, affecting reward as well as movement.

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Savitz, Jonathan; Hodgkinson, Colin A; Martin-Soelch, Chantal; Shen, Pei-Hong; Szczepanik, Joanna; Nugent, Allison; Herscovitch, Peter; Grace, Anthony A; Goldman, David; Drevets, Wayne C

2013-01-01

Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3) gene (ser9gly, rs6280) on reward-associated dopamine (DA) release in the striatum. Twenty-six healthy controls (HCs) and 10 unmedicated subjects with major depressive disorder (MDD) completed two positron emission tomography (PET) scans with [(11)C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition) and on another occasion subjects completed a gambling task (reward condition). A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release) in the middle (anterior) caudate (p<0.01) and the ventral striatum (p<0.05). The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis.
The functional DRD3 Ser9Gly polymorphism (rs6280 is pleiotropic, affecting reward as well as movement.

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Jonathan Savitz

Full Text Available Abnormalities of motivation and behavior in the context of reward are a fundamental component of addiction and mood disorders. Here we test the effect of a functional missense mutation in the dopamine 3 receptor (DRD3 gene (ser9gly, rs6280 on reward-associated dopamine (DA release in the striatum. Twenty-six healthy controls (HCs and 10 unmedicated subjects with major depressive disorder (MDD completed two positron emission tomography (PET scans with [(11C]raclopride using the bolus plus constant infusion method. On one occasion subjects completed a sensorimotor task (control condition and on another occasion subjects completed a gambling task (reward condition. A linear regression analysis controlling for age, sex, diagnosis, and self-reported anhedonia indicated that during receipt of unpredictable monetary reward the glycine allele was associated with a greater reduction in D2/3 receptor binding (i.e., increased reward-related DA release in the middle (anterior caudate (p<0.01 and the ventral striatum (p<0.05. The possible functional effect of the ser9gly polymorphism on DA release is consistent with previous work demonstrating that the glycine allele yields D3 autoreceptors that have a higher affinity for DA and display more robust intracellular signaling. Preclinical evidence indicates that chronic stress and aversive stimulation induce activation of the DA system, raising the possibility that the glycine allele, by virtue of its facilitatory effect on striatal DA release, increases susceptibility to hyperdopaminergic responses that have previously been associated with stress, addiction, and psychosis.
Regulation of pokemon 1 activity by sumoylation.

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Roh, Hee-Eun; Lee, Min-Nyung; Jeon, Bu-Nam; Choi, Won-Il; Kim, Yoo-Jin; Yu, Mi-Young; Hur, Man-Wook

2007-01-01

Pokemon 1 is a proto-oncogenic transcriptional regulator that contains a POZ domain at the N-terminus and four Kruppel-like zinc fingers at the C-terminus. Pokemon 1 plays an important role in adipogenesis, osteogenesis, oncogenesis, and transcription of NF-kB responsive genes. Recent reports have shown that biological activities of transcription factors are regulated by sumolylation. We investigated whether Pokemon 1 is post-translationally modified by sumoylation and whether the modification affects Pokemon 1's transcriptional properties. We found that Pokemon 1 is sumoylated in vitro and in vivo. Upon careful analysis of the amino acid sequence of Pokemon 1, we found ten potential sumoylation sites located at lysines 61, 354, 371, 379, 383, 396, 486, 487, 536 and 539. We mutated each of these amino acids into arginine and tested whether the mutation could affect the transcriptional properties of Pokemon 1 on the Pokemon 1 responsive genes, such as ADH5/FDH and pG5-FRE-Luc. Wild-type Pokemon 1 potently represses transcription of ADH5/FDH. Most of the mutants, however, were weaker transcription repressors and repressed transcription 1.3-3.3 fold less effective. Although potential sumoylation sites were located close to the DNA binding domain or the nuclear localization sequence, the mutations did not alter nuclear localization or DNA binding activity. In addition, on the pG5-FRE-Luc test promoter construct, ectopic SUMO-1 repressed transcription in the presence of Pokemon 1. The sumoylation target lysine residue at amino acid 61, which is located in the middle of the POZ-domain, is important because K61R mutation resulted in a much weaker molecular interaction with corepressors. Our data suggest that Pokemon 1's activity as a transcription factor may involve sumoylation, and that sumoylation might be important in the regulation of transcription by Pokemon 1.
Dissecting the active site of the collagenolytic cathepsin L3 protease of the invasive stage of Fasciola hepatica.

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Ileana Corvo

Full Text Available A family of secreted cathepsin L proteases with differential activities is essential for host colonization and survival in the parasitic flatworm Fasciola hepatica. While the blood feeding adult secretes predominantly FheCL1, an enzyme with a strong preference for Leu at the S2 pocket of the active site, the infective stage produces FheCL3, a unique enzyme with collagenolytic activity that favours Pro at P2.Using a novel unbiased multiplex substrate profiling and mass spectrometry methodology (MSP-MS, we compared the preferences of FheCL1 and FheCL3 along the complete active site cleft and confirm that while the S2 imposes the greatest influence on substrate selectivity, preferences can be indicated on other active site subsites. Notably, we discovered that the activity of FheCL1 and FheCL3 enzymes is very different, sharing only 50% of the cleavage sites, supporting the idea of functional specialization. We generated variants of FheCL1 and FheCL3 with S2 and S3 residues by mutagenesis and evaluated their substrate specificity using positional scanning synthetic combinatorial libraries (PS-SCL. Besides the rare P2 Pro preference, FheCL3 showed a distinctive specificity at the S3 pocket, accommodating preferentially the small Gly residue. Both P2 Pro and P3 Gly preferences were strongly reduced when Trp67 of FheCL3 was replaced by Leu, rendering the enzyme incapable of digesting collagen. In contrast, the inverse Leu67Trp substitution in FheCL1 only slightly reduced its Leu preference and improved Pro acceptance in P2, but greatly increased accommodation of Gly at S3.These data reveal the significance of S2 and S3 interactions in substrate binding emphasizing the role for residue 67 in modulating both sites, providing a plausible explanation for the FheCL3 collagenolytic activity essential to host invasion. The unique specificity of FheCL3 could be exploited in the design of specific inhibitors selectively directed to specific infective stage
Characterization of serine hydroxymethyltransferase GlyA as a potential source of D-alanine in Chlamydia pneumoniae.

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De Benedetti, Stefania; Bühl, Henrike; Gaballah, Ahmed; Klöckner, Anna; Otten, Christian; Schneider, Tanja; Sahl, Hans-Georg; Henrichfreise, Beate

2014-01-01

For intracellular Chlamydiaceae, there is no need to withstand osmotic challenges, and a functional cell wall has not been detected in these pathogens so far. Nevertheless, penicillin inhibits cell division in Chlamydiaceae resulting in enlarged aberrant bodies, a phenomenon known as chlamydial anomaly. D-alanine is a unique and essential component in the biosynthesis of bacterial cell walls. In free-living bacteria like Escherichia coli, penicillin-binding proteins such as monofunctional transpeptidases PBP2 and PBP3, the putative targets of penicillin in Chlamydiaceae, cross-link adjacent peptidoglycan strands via meso-diaminopimelic acid and D-Ala-D-Ala moieties of pentapeptide side chains. In the absence of genes coding for alanine racemase Alr and DadX homologs, the source of D-Ala and thus the presence of substrates for PBP2 and PBP3 activity in Chlamydiaceae has puzzled researchers for years. Interestingly, Chlamydiaceae genomes encode GlyA, a serine hydroxymethyltransferase that has been shown to exhibit slow racemization of D- and L-alanine as a side reaction in E. coli. We show that GlyA from Chlamydia pneumoniae can serve as a source of D-Ala. GlyA partially reversed the D-Ala auxotrophic phenotype of an E. coli racemase double mutant. Moreover, purified chlamydial GlyA had racemase activity on L-Ala in vitro and was inhibited by D-cycloserine, identifying GlyA, besides D-Ala ligase MurC/Ddl, as an additional target of this competitive inhibitor in Chlamydiaceae. Proof of D-Ala biosynthesis in Chlamydiaceae helps to clarify the structure of cell wall precursor lipid II and the role of chlamydial penicillin-binding proteins in the development of non-dividing aberrant chlamydial bodies and persistence in the presence of penicillin.
Characterization of serine hydroxymethyltransferase GlyA as a potential source of D-alanine in Chlamydia pneumoniae

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Stefania eDe Benedetti

2014-02-01

Full Text Available For intracellular Chlamydiaceae, there is no need to withstand osmotic challenges, and a functional cell wall has not been detected in these pathogens so far. Nevertheless, penicillin inhibits cell division in Chlamydiaceae resulting in enlarged aberrant bodies, a phenomenon known as chlamydial anomaly.D-alanine is a unique and essential component in the biosynthesis of bacterial cell walls. In free-living bacteria like Escherichia coli, penicillin-binding proteins such as monofunctional transpeptidases PBP2 and PBP3, the putative targets of penicillin in Chlamydiaceae, cross-link adjacent peptidoglycan strands via meso-diaminopimelic acid and D-Ala-D-Ala moieties of pentapeptide side chains. In the absence of genes coding for alanine racemase Alr and DadX homologs, the source of D-Ala and thus the presence of substrates for PBP2 and PBP3 activity in Chlamydiaceae has puzzled researchers for years. Interestingly, Chlamydiaceae genomes encode GlyA, a serine hydroxymethyltransferase that has been shown to exhibit slow racemization of D- and L- alanine as a side reaction in E. coli. We show that GlyA from Chlamydia pneumoniae can serve as a source of D-Ala. GlyA partially reversed the D-Ala auxotrophic phenotype of an E. coli racemase double mutant. Moreover, purified chlamydial GlyA had racemase activity on L-Ala in vitro and was inhibited by D-cycloserine, identifying GlyA, besides D-Ala ligase MurC/Ddl, as an additional target of this competitive inhibitor in Chlamydiaceae. Proof of D-Ala biosynthesis in Chlamydiaceae helps to clarify the structure of cell wall precursor lipid II and the role of chlamydial penicillin-binding proteins in the development of non-dividing aberrant chlamydial bodies and persistence in the presence of penicillin.
Promoter proximal polyadenylation sites reduce transcription activity

DEFF Research Database (Denmark)

Andersen, Pia Kjølhede; Lykke-Andersen, Søren; Jensen, Torben Heick

2012-01-01

Gene expression relies on the functional communication between mRNA processing and transcription. We previously described the negative impact of a point-mutated splice donor (SD) site on transcription. Here we demonstrate that this mutation activates an upstream cryptic polyadenylation (CpA) site......, which in turn causes reduced transcription. Functional depletion of U1 snRNP in the context of the wild-type SD triggers the same CpA event accompanied by decreased RNA levels. Thus, in accordance with recent findings, U1 snRNP can shield premature pA sites. The negative impact of unshielded pA sites...... on transcription requires promoter proximity, as demonstrated using artificial constructs and supported by a genome-wide data set. Importantly, transcription down-regulation can be recapitulated in a gene context devoid of splice sites by placing a functional bona fide pA site/transcription terminator within ∼500...
Transcription factor FoxO1 is essential for enamel biomineralization.

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Ross A Poché

Full Text Available The Transforming growth factor β (Tgf-β pathway, by signaling via the activation of Smad transcription factors, induces the expression of many diverse downstream target genes thereby regulating a vast array of cellular events essential for proper development and homeostasis. In order for a specific cell type to properly interpret the Tgf-β signal and elicit a specific cellular response, cell-specific transcriptional co-factors often cooperate with the Smads to activate a discrete set of genes in the appropriate temporal and spatial manner. Here, via a conditional knockout approach, we show that mice mutant for Forkhead Box O transcription factor FoxO1 exhibit an enamel hypomaturation defect which phenocopies that of the Smad3 mutant mice. Furthermore, we determined that both the FoxO1 and Smad3 mutant teeth exhibit changes in the expression of similar cohort of genes encoding enamel matrix proteins required for proper enamel development. These data raise the possibility that FoxO1 and Smad3 act in concert to regulate a common repertoire of genes necessary for complete enamel maturation. This study is the first to define an essential role for the FoxO family of transcription factors in tooth development and provides a new molecular entry point which will allow researchers to delineate novel genetic pathways regulating the process of biomineralization which may also have significance for studies of human tooth diseases such as amelogenesis imperfecta.
Regulation of hepatitis B virus ENI enhancer activity by hepatocyte-enriched transcription factor HNF3.

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Chen, M; Hieng, S; Qian, X; Costa, R; Ou, J H

1994-11-15

Hepatitis B virus (HBV) ENI enhancer can activate the expression of HBV and non-HBV genes in a liver-specific manner. By performing the electrophoretic mobility-shift assays, we demonstrated that the three related, liver-enriched, transcription factors, HNF3 alpha, HNF3 beta, and HNF3 gamma could all bind to the 2c site of HBV ENI enhancer. Mutations introduced in the 2c site to abolish the binding by HNF3 reduced the enhancer activity approximately 15-fold. Moreover, expression of HNF3 antisense sequences to suppress the expression of HNF3 in Huh-7 hepatoma cells led to reduction of the ENI enhancer activity. These results indicate that HNF3 positively regulates the ENI enhancer activity and this regulation is most likely mediated through the 2c site. The requirement of HNF3 for the ENI enhancer activity could explain the liver specificity of this enhancer element.
Cross-talk between an activator of nuclear receptors-mediated transcription and the D1 dopamine receptor signaling pathway.

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Schmidt, Azriel; Vogel, Robert; Rutledge, Su Jane; Opas, Evan E; Rodan, Gideon A; Friedman, Eitan

2005-03-01

Nuclear receptors are transcription factors that usually interact, in a ligand-dependent manner, with specific DNA sequences located within promoters of target genes. The nuclear receptors can also be controlled in a ligand-independent manner via the action of membrane receptors and cellular signaling pathways. 5-Tetradecyloxy-2-furancarboxylic acid (TOFA) was shown to stimulate transcription from the MMTV promoter via chimeric receptors that consist of the DNA binding domain of GR and the ligand binding regions of the PPARbeta or LXRbeta nuclear receptors (GR/PPARbeta and GR/LXRbeta). TOFA and hydroxycholesterols also modulate transcription from NF-kappaB- and AP-1-controlled reporter genes and induce neurite differentiation in PC12 cells. In CV-1 cells that express D(1) dopamine receptors, D(1) dopamine receptor stimulation was found to inhibit TOFA-stimulated transcription from the MMTV promoter that is under the control of chimeric GR/PPARbeta and GR/LXRbeta receptors. Treatment with the D(1) dopamine receptor antagonist, SCH23390, prevented dopamine-mediated suppression of transcription, and by itself increased transcription controlled by GR/LXRbeta. Furthermore, combined treatment of CV-1 cells with TOFA and SCH23390 increased transcription controlled by the GR/LXRbeta chimeric receptor synergistically. The significance of this in vitro synergy was demonstrated in vivo, by the observation that SCH23390 (but not haloperidol)-mediated catalepsy in rats was potentiated by TOFA, thus showing that an agent that mimics the in vitro activities of compounds that activate members of the LXR and PPAR receptor families can influence D1 dopamine receptor elicited responses.
Direct Assessment of the Effect of the Gly380Arg Achondroplasia Mutation on FGFR3 Dimerization Using Quantitative Imaging FRET

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Placone, Jesse; Hristova, Kalina

2012-01-01

The Gly380Arg mutation in FGFR3 is the genetic cause for achondroplasia (ACH), the most common form of human dwarfism. The mutation has been proposed to increase FGFR3 dimerization, but the dimerization propensities of wild-type and mutant FGFR3 have not been compared. Here we use quantitative imaging FRET to characterize the dimerization of wild-type FGFR3 and the ACH mutant in plasma membrane-derived vesicles from HEK293T cells. We demonstrate a small, but statistically significant increase in FGFR3 dimerization due to the ACH mutation. The data are consistent with the idea that the ACH mutation causes a structural change which affects both the stability and the activity of FGFR3 dimers in the absence of ligand. PMID:23056398
AKT activation drives the nuclear localization of CSE1L and a pro-oncogenic transcriptional activation in ovarian cancer cells.

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Lorenzato, Annalisa; Biolatti, Marta; Delogu, Giuseppe; Capobianco, Giampiero; Farace, Cristiano; Dessole, Salvatore; Cossu, Antonio; Tanda, Francesco; Madeddu, Roberto; Olivero, Martina; Di Renzo, Maria Flavia

2013-10-15

The human homolog of the yeast cse1 gene (CSE1L) is over-expressed in ovarian cancer. CSE1L forms complex with Ran and importin-α and has roles in nucleocytoplasmic traffic and gene expression. CSE1L accumulated in the nucleus of ovarian cancer cell lines, while it was localized also in the cytoplasm of other cancer cell lines. Nuclear localization depended on AKT, which was constitutively active in ovarian cancer cells, as the CSE1L protein translocated to the cytoplasm when AKT was inactivated. Moreover, the expression of a constitutively active AKT forced the translocation of CSE1L from the cytoplasm to the nucleus in other cancer cells. Nuclear accrual of CSE1L was associated to the nuclear accumulation of the phosphorylated Ran Binding protein 3 (RanBP3), which depended on AKT as well. Also in samples of human ovarian cancer, AKT activation was associated to nuclear accumulation of CSE1L and phosphorylation of RanBP3. Expression profiling of ovarian cancer cells after CSE1L silencing showed that CSE1L was required for the expression of genes promoting invasion and metastasis. In agreement, CSE1L silencing impaired motility and invasiveness of ovarian cancer cells. Altogether these data show that in ovarian cancer cells activated AKT by affecting RanBP3 phosphorylation determines the nuclear accumulation of CSE1L and likely the nuclear concentration of transcription factors conveying pro-oncogenic signals. © 2013 Elsevier Inc. All rights reserved.

Enterovirus type 71 2A protease functions as a transcriptional activator in yeast

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Lai Meng-Jiun

2010-08-01

Full Text Available Abstract Enterovirus type 71 (EV71 2A protease exhibited strong transcriptional activity in yeast cells. The transcriptional activity of 2A protease was independent of its protease activity. EV71 2A protease retained its transcriptional activity after truncation of 40 amino acids at the N-terminus but lost this activity after truncation of 60 amino acids at the N-terminus or deletion of 20 amino acids at the C-terminus. Thus, the acidic domain at the C-terminus of this protein is essential for its transcriptional activity. Indeed, deletion of amino acids from 146 to 149 (EAME in this acidic domain lost the transcriptional activity of EV71 2A protein though still retained its protease activity. EV71 2A protease was detected both in the cytoplasm and nucleus using confocal microscopy analysis. Coxsackie virus B3 2A protease also exhibited transcriptional activity in yeast cells. As expected, an acidic domain in the C-terminus of Coxsackie virus B3 2A protease was also identified. Truncation of this acidic domain resulted in the loss of transcriptional activity. Interestingly, this acidic region of poliovirus 2A protease is critical for viral RNA replication. The transcriptional activity of the EV71 or Coxsackie virus B3 2A protease should play a role in viral replication and/or pathogenesis.
Positive selection at codon 38 of the human KCNE1 (= minK gene and sporadic absence of 38Ser-coding mRNAs in Gly38Ser heterozygotes

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Pfeufer Arne

2009-08-01

Full Text Available Abstract Background KCNE1 represents the regulatory beta-subunit of the slowly activating delayed rectifier potassium channel (IKs. Variants of KCNE1 have repeatedly been linked to the long-QT syndrome (LQTS, a disorder which predisposes to deafness, ventricular tachyarrhythmia, syncope, and sudden cardiac death. Results We here analyze the evolution of the common Gly38Ser variant (rs1805127, using genomic DNAs, complementary DNAs, and HEK293-expressed variants of altogether 19 mammalian species. The between species comparison reveals that the human-specific Gly38Ser polymorphism evolved under strong positive Darwinian selection, probably in adaptation to specific challenges in the fine-tuning of IKs channels. The involved amino acid exchanges (Asp > Gly, Gly > Ser are moderately radical and do not induce apparent changes in posttranslational modification. According to population genetic analyses (HapMap phase II a heterozygote advantage accounts for the maintenance of the Gly38Ser polymorphism in humans. On the other hand, the expression of the 38Ser allele seems to be disadvantageous under certain conditions, as suggested by the sporadic deficiency of 38Ser-coding mRNAs in heterozygote Central Europeans and the depletion of homozygotes 38Ser in the Yoruban sample. Conclusion We speculate that individual differences in genomic imprinting or genomic recoding might have contributed to conflicting results of recent association studies between Gly38Ser polymorphism and QT phenotype. The findings thus highlight the relevance of mRNA data in future association studies of genotypes and clinical disorders. To the best of our knowledge, they moreover provide first time evidence for a unique pattern; i.e. coincidence of positive Darwinian selection and polymorphism with a sporadically suppressed expression of one allele.
MiT/TFE transcription factors are activated during mitophagy downstream of Parkin and Atg5.

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Nezich, Catherine L; Wang, Chunxin; Fogel, Adam I; Youle, Richard J

2015-08-03

The kinase PINK1 and ubiquitin ligase Parkin can regulate the selective elimination of damaged mitochondria through autophagy (mitophagy). Because of the demand on lysosomal function by mitophagy, we investigated a role for the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, in this process. We show that during mitophagy TFEB translocates to the nucleus and displays transcriptional activity in a PINK1- and Parkin-dependent manner. MITF and TFE3, homologues of TFEB belonging to the same microphthalmia/transcription factor E (MiT/TFE) family, are similarly regulated during mitophagy. Unlike TFEB translocation after starvation-induced mammalian target of rapamycin complex 1 inhibition, Parkin-mediated TFEB relocalization required Atg9A and Atg5 activity. However, constitutively active Rag guanosine triphosphatases prevented TFEB translocation during mitophagy, suggesting cross talk between these two MiT/TFE activation pathways. Analysis of clustered regularly interspaced short palindromic repeats-generated TFEB/MITF/TFE3/TFEC single, double, and triple knockout cell lines revealed that these proteins partly facilitate Parkin-mediated mitochondrial clearance. These results illuminate a pathway leading to MiT/TFE transcription factor activation, distinct from starvation-induced autophagy, which occurs during mitophagy.
Characterization of a beta-glycosidase highly active on disaccharides and of a beta-galactosidase from Tenebrio molitor midgut lumen.

Science.gov (United States)

Ferreira, Alexandre H P; Terra, Walter R; Ferreira, Clélia

2003-02-01

The midgut of the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae) larvae has four beta-glycosidases. The properties of two of these enzymes (betaGly1 and betaGly2) have been described elsewhere. In this paper, the characterization of the other two glycosidases (betaGly3 and betaGly4) is described. BetaGly3 has one active site, hydrolyzes disaccharides, cellodextrins, synthetic substrates and beta-glucosides produced by plants. The enzyme is inhibited by amygdalin, cellotriose, cellotetraose and cellopentaose in high concentrations, probably due to transglycosylation. betaGly3 hydrolyzes beta 1,4-glycosidic linkages with a catalytic rate independent of the substrate polymerization degree (k(int)) of 11.9 s(-1). Its active site is formed by four subsites, where subsites +1 and -1 bind glucose residues with higher affinity than subsite +2. The main role of betaGly3 seems to be disaccharide hydrolysis. BetaGly4 is a beta-galactosidase, since it has highest activity against beta-galactosides. It can also hydrolyze fucosides, but not glucosides, and has Triton X-100 as a non-essential activator (K(a)=15 microM, pH 4.5). betaGly4 has two active sites that can hydrolyze p-nitrophenyl beta-galactoside (NPbetaGal). The one hydrolyzing NPbetaGal with more efficiency is also active against methylumbellipheryl beta-D-galactoside and lactose. The other active site hydrolyzes NPbetaFucoside and binds NPbetaGal weakly. BetaGly4 hydrolyzes hydrophobic substrates with high catalytical efficiency and is able to bind octyl-beta-thiogalactoside in its active site with high affinity. The betaGly4 physiological role is supposed to be the hydrolysis of galactolipids that are found in membranes from vegetal tissues. As the enzyme has a hydrophobic site where Triton X-100 can bind, it might be activated by membrane lipids, thus becoming fully active only at the surface of cell membranes.
Characterization and sequencing of the active site of 1-aminocyclopropane-1-carboxylate synthase

International Nuclear Information System (INIS)

Yip, Wing-Kin; Dong, Jian-Guo; Yang, S.F.; Kenny, J.W.; Thompson, G.A.

1990-01-01

The pyridoxal phosphate (PLP)-dependent 1-aminocyclopropane-1-carboxylic acid (ACC) synthase the key enzyme in ethylene biosynthesis, is inactivated by its substrate S-adenosylmethionine (AdoMet). Apple ACC synthase was purified with an immunoaffinity gel, and its active site was probed with NaB 3 H 4 or Ado[ 14 C]Met. Peptide sequencing of both 3 H- and 14 C-labeled peptides revealed a common dodecapeptide of Ser-Leu-Ser-Xaa-Asp-Leu-Gly-Leu-Pro-Gly-Phe-Arg, where Xaa was the modified, radioactive residue in each case. Acid hydrolysis of the 3 H-labeled enzyme released radioactive N-pyridoxyllysine, indicating that the active-site peptide contained lysine at position 4. Mass spectrometry of the 14 C-labeled peptide indicated a protonated molecular ion at m/z 1390.6, from which the mass of Xaa was calculated to be 229, a number that is equivalent to the mass of a lysine residue alkylated by the 2-aminobutyrate portion of AdoMet, as we previously proposed. These results indicate that the same active-site lysine binds the PLP and convalently links to the 2-aminobutyrate portion of AdoMet during inactivation. The active site of tomato ACC synthase was probed in the same manner with Ado [ 14 C]Met. Sequencing of the tomato active-site peptide revealed two highly conserved dodecapeptides; the minor peptide possessed a sequence identical to that of the apple enzyme, whereas the major peptide differed from the minor peptide in that methionine replaced leucine at position 6
Potential Role of Activating Transcription Factor 5 during Osteogenesis

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Luisa Vicari

2016-01-01

Full Text Available Human adipose-derived stem cells are an abundant population of stem cells readily isolated from human adipose tissue that can differentiate into connective tissue lineages including bone, cartilage, fat, and muscle. Activating transcription factor 5 is a transcription factor of the ATF/cAMP response element-binding protein (CREB family. It is transcribed in two types of mRNAs (activating transcription factor 5 isoform 1 and activating transcription factor 5 isoform 2, encoding the same single 30-kDa protein. Although it is well demonstrated that it regulates the proliferation, differentiation, and apoptosis, little is known about its potential role in osteogenic differentiation. The aim of this study was to evaluate the expression levels of the two isoforms and protein during osteogenic differentiation of human adipose-derived stem cells. Our data indicate that activating transcription factor 5 is differentially expressed reaching a peak of expression at the stage of bone mineralization. These findings suggest that activating transcription factor 5 could play an interesting regulatory role during osteogenesis, which would provide a powerful tool to study bone physiology.
Potential Role of Activating Transcription Factor 5 during Osteogenesis.

Science.gov (United States)

Vicari, Luisa; Calabrese, Giovanna; Forte, Stefano; Giuffrida, Raffaella; Colarossi, Cristina; Parrinello, Nunziatina Laura; Memeo, Lorenzo

2016-01-01

Human adipose-derived stem cells are an abundant population of stem cells readily isolated from human adipose tissue that can differentiate into connective tissue lineages including bone, cartilage, fat, and muscle. Activating transcription factor 5 is a transcription factor of the ATF/cAMP response element-binding protein (CREB) family. It is transcribed in two types of mRNAs (activating transcription factor 5 isoform 1 and activating transcription factor 5 isoform 2), encoding the same single 30-kDa protein. Although it is well demonstrated that it regulates the proliferation, differentiation, and apoptosis, little is known about its potential role in osteogenic differentiation. The aim of this study was to evaluate the expression levels of the two isoforms and protein during osteogenic differentiation of human adipose-derived stem cells. Our data indicate that activating transcription factor 5 is differentially expressed reaching a peak of expression at the stage of bone mineralization. These findings suggest that activating transcription factor 5 could play an interesting regulatory role during osteogenesis, which would provide a powerful tool to study bone physiology.
Constitutive endocytosis and turnover of the neuronal glycine transporter GlyT2 is dependent on ubiquitination of a C-terminal lysine cluster.

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Jaime de Juan-Sanz

Full Text Available Inhibitory glycinergic neurotransmission is terminated by sodium and chloride-dependent plasma membrane glycine transporters (GlyTs. The mainly glial glycine transporter GlyT1 is primarily responsible for the completion of inhibitory neurotransmission and the neuronal glycine transporter GlyT2 mediates the reuptake of the neurotransmitter that is used to refill synaptic vesicles in the terminal, a fundamental role in the physiology and pathology of glycinergic neurotransmission. Indeed, inhibitory glycinergic neurotransmission is modulated by the exocytosis and endocytosis of GlyT2. We previously reported that constitutive and Protein Kinase C (PKC-regulated endocytosis of GlyT2 is mediated by clathrin and that PKC accelerates GlyT2 endocytosis by increasing its ubiquitination. However, the role of ubiquitination in the constitutive endocytosis and turnover of this protein remains unexplored. Here, we show that ubiquitination of a C-terminus four lysine cluster of GlyT2 is required for constitutive endocytosis, sorting into the slow recycling pathway and turnover of the transporter. Ubiquitination negatively modulates the turnover of GlyT2, such that increased ubiquitination driven by PKC activation accelerates transporter degradation rate shortening its half-life while decreased ubiquitination increases transporter stability. Finally, ubiquitination of GlyT2 in neurons is highly responsive to the free pool of ubiquitin, suggesting that the deubiquitinating enzyme (DUB ubiquitin C-terminal hydrolase-L1 (UCHL1, as the major regulator of neuronal ubiquitin homeostasis, indirectly modulates the turnover of GlyT2. Our results contribute to the elucidation of the mechanisms underlying the dynamic trafficking of this important neuronal protein which has pathological relevance since mutations in the GlyT2 gene (SLC6A5 are the second most common cause of human hyperekplexia.
Estrogen promotes megakaryocyte polyploidization via estrogen receptor beta-mediated transcription of GATA1.

Science.gov (United States)

Du, C; Xu, Y; Yang, K; Chen, S; Wang, X; Wang, S; Wang, C; Shen, M; Chen, F; Chen, M; Zeng, D; Li, F; Wang, T; Wang, F; Zhao, J; Ai, G; Cheng, T; Su, Y; Wang, J

2017-04-01

Estrogen is reported to be involved in thrombopoiesis and the disruption of its signaling may cause myeloproliferative disease, yet the underlying mechanisms remain largely unknown. GATA-binding factor 1 (GATA1) is a key regulator of megakaryocyte (MK) differentiation and its deficiency will lead to megakaryoblastic leukemia. Here we show that estrogen can dose-dependently promote MK polyploidization and maturation via activation of estrogen receptor beta (ERβ), accompanied by a significant upregulation of GATA1. Chromatin immunoprecipitation and a dual luciferase assay demonstrate that ERβ can directly bind the promoter region of GATA1 and activate its transcription. Steroid receptor coactivator 3 (SRC3) is involved in ERβ-mediated GATA1 transcription. The deficiency of ERβ or SRC3, similar to the inhibition of GATA1, leads to the impediment of estrogen-induced MK polyploidization and platelet production. Further investigations reveal that signal transducer and activator of transcription 1 signaling pathway downstream of GATA1 has a crucial role in estrogen-induced MK polyploidization, and ERβ-mediated GATA1 upregulation subsequently enhances nuclear factor erythroid-derived 2 expression, thereby promoting proplatelet formation and platelet release. Our study provides a deep insight into the molecular mechanisms of estrogen signaling in regulating thrombopoiesis and the pathogenesis of ER deficiency-related leukemia.
Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPβ expression and activation

International Nuclear Information System (INIS)

Chen, Ching-Chu; Chuang, Wei-Ting; Lin, Ai-Hsuan; Tsai, Chia-Wen; Huang, Chin-Shiu; Chen, Yun-Ting; Chen, Haw-Wen; Lii, Chong-Kuei

2016-01-01

Andrographolide, a diterpenoid, is the most abundant terpenoid in Andrographis paniculata, a popular Chinese herbal medicine. Andrographolide displays diverse biological activities including hypoglycemia, hypolipidemia, anti-inflammation, and anti-tumorigenesis. Recent evidence indicates that andrographolide displays anti-obesity property by inhibiting lipogenic gene expression, however, the underlying mechanisms remain to be elucidated. In this study, the effects of andrographolide on transcription factor cascade and mitotic clonal expansion in 3T3-L1 preadipocyte differentiation into adipocyte were determined. Andrographolide dose-dependently (0–15 μM) inhibited CCAAT/enhancer-binding protein α (C/EBPα) and C/EBPβ mRNA and protein expression as well as peroxisome proliferator-activated receptor γ (PPARγ) protein level during the adipogenesis of 3T3-L1 cells. Concomitantly, fatty acid synthase and stearoyl-CoA desaturase expression and lipid accumulation were attenuated by andrographolide. Oil-red O staining further showed that the first 48 h after the initiation of differentiation was critical for andrographolide inhibition of adipocyte formation. Andrographolide inhibited the phosphorylation of PKA and the activation of cAMP response element-binding protein (CREB) in response to a differentiation cocktail, which led to attenuated C/EBPβ expression. In addition, ERK and GSK3β-dependent C/EBPβ phosphorylation was attenuated by andrographolide. Moreover, andrographolide suppressed cyclin A, cyclin E, and CDK2 expression and impaired the progression of mitotic clonal expansion (MCE) by arresting the cell cycle at the Go/G1 phase. Taken together, these results indicate that andrographolide has a potent anti-obesity action by inhibiting PKA-CREB-mediated C/EBPβ expression as well as C/EBPβ transcriptional activity, which halts MCE progression and attenuates C/EBPα and PPARγ expression. - Highlights: • Andrographolide is a diterpenoid phytochemical. �
Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPβ expression and activation

Energy Technology Data Exchange (ETDEWEB)

Chen, Ching-Chu [Division of Endocrinology and Metabolism, Department of Medicine, China Medical University Hospital, Taichung, Taiwan (China); Division of Endocrinology and Metabolism, Department of Chinese Medicine, China Medical University, China Medical University, Taichung, Taiwan (China); Chuang, Wei-Ting; Lin, Ai-Hsuan; Tsai, Chia-Wen [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Huang, Chin-Shiu [Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Chen, Yun-Ting [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Chen, Haw-Wen, E-mail: chenhw@mail.cmu.edu.tw [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Lii, Chong-Kuei, E-mail: cklii@mail.cmu.edu.tw [Department of Nutrition, China Medical University, Taichung, Taiwan (China); Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan (China)

2016-09-15

Andrographolide, a diterpenoid, is the most abundant terpenoid in Andrographis paniculata, a popular Chinese herbal medicine. Andrographolide displays diverse biological activities including hypoglycemia, hypolipidemia, anti-inflammation, and anti-tumorigenesis. Recent evidence indicates that andrographolide displays anti-obesity property by inhibiting lipogenic gene expression, however, the underlying mechanisms remain to be elucidated. In this study, the effects of andrographolide on transcription factor cascade and mitotic clonal expansion in 3T3-L1 preadipocyte differentiation into adipocyte were determined. Andrographolide dose-dependently (0–15 μM) inhibited CCAAT/enhancer-binding protein α (C/EBPα) and C/EBPβ mRNA and protein expression as well as peroxisome proliferator-activated receptor γ (PPARγ) protein level during the adipogenesis of 3T3-L1 cells. Concomitantly, fatty acid synthase and stearoyl-CoA desaturase expression and lipid accumulation were attenuated by andrographolide. Oil-red O staining further showed that the first 48 h after the initiation of differentiation was critical for andrographolide inhibition of adipocyte formation. Andrographolide inhibited the phosphorylation of PKA and the activation of cAMP response element-binding protein (CREB) in response to a differentiation cocktail, which led to attenuated C/EBPβ expression. In addition, ERK and GSK3β-dependent C/EBPβ phosphorylation was attenuated by andrographolide. Moreover, andrographolide suppressed cyclin A, cyclin E, and CDK2 expression and impaired the progression of mitotic clonal expansion (MCE) by arresting the cell cycle at the Go/G1 phase. Taken together, these results indicate that andrographolide has a potent anti-obesity action by inhibiting PKA-CREB-mediated C/EBPβ expression as well as C/EBPβ transcriptional activity, which halts MCE progression and attenuates C/EBPα and PPARγ expression. - Highlights: • Andrographolide is a diterpenoid phytochemical. �
Nitrogen Starvation and TorC1 Inhibition Differentially Affect Nuclear Localization of the Gln3 and Gat1 Transcription Factors Through the Rare Glutamine tRNACUG in Saccharomyces cerevisiae

Science.gov (United States)

Tate, Jennifer J.; Rai, Rajendra; Cooper, Terrance G.

2015-01-01

A leucine, leucyl-tRNA synthetase–dependent pathway activates TorC1 kinase and its downstream stimulation of protein synthesis, a major nitrogen consumer. We previously demonstrated, however, that control of Gln3, a transcription activator of catabolic genes whose products generate the nitrogenous precursors for protein synthesis, is not subject to leucine-dependent TorC1 activation. This led us to conclude that excess nitrogen-dependent down-regulation of Gln3 occurs via a second mechanism that is independent of leucine-dependent TorC1 activation. A major site of Gln3 and Gat1 (another GATA-binding transcription activator) control occurs at their access to the nucleus. In excess nitrogen, Gln3 and Gat1 are sequestered in the cytoplasm in a Ure2-dependent manner. They become nuclear and activate transcription when nitrogen becomes limiting. Long-term nitrogen starvation and treatment of cells with the glutamine synthetase inhibitor methionine sulfoximine (Msx) also elicit nuclear Gln3 localization. The sensitivity of Gln3 localization to glutamine and inhibition of glutamine synthesis prompted us to investigate the effects of a glutamine tRNA mutation (sup70-65) on nitrogen-responsive control of Gln3 and Gat1. We found that nuclear Gln3 localization elicited by short- and long-term nitrogen starvation; growth in a poor, derepressive medium; Msx or rapamycin treatment; or ure2Δ mutation is abolished in a sup70-65 mutant. However, nuclear Gat1 localization, which also exhibits a glutamine tRNACUG requirement for its response to short-term nitrogen starvation or growth in proline medium or a ure2Δ mutation, does not require tRNACUG for its response to rapamycin. Also, in contrast with Gln3, Gat1 localization does not respond to long-term nitrogen starvation. These observations demonstrate the existence of a specific nitrogen-responsive component participating in the control of Gln3 and Gat1 localization and their downstream production of nitrogenous precursors
Keap1 silencing boosts lipopolysaccharide-induced transcription of interleukin 6 via activation of nuclear factor κB in macrophages

International Nuclear Information System (INIS)

Lv, Peng; Xue, Peng; Dong, Jian; Peng, Hui; Clewell, Rebecca; Wang, Aiping; Wang, Yue; Peng, Shuangqing; Qu, Weidong; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

2013-01-01

Interleukin-6 (IL6) is a multifunctional cytokine that regulates immune and inflammatory responses. Multiple transcription factors, including nuclear factor κB (NF-κB) and nuclear factor E2-related factor 2 (Nrf2), regulate IL6 transcription. Kelch-like ECH-associated protein 1 (Keap1) is a substrate adaptor protein for the Cullin 3-dependent E3 ubiquitin ligase complex, which regulates the degradation of many proteins, including Nrf2 and IκB kinase β (IKKβ). Here, we found that stable knockdown of Keap1 (Keap1-KD) in RAW 264.7 (RAW) mouse macrophages and human monocyte THP-1 cells significantly increased expression of Il6, and Nrf2-target genes, under basal and lipopolysaccharide (LPS, 0.001–0.1 μg/ml)-challenged conditions. However, Nrf2 activation alone, by tert-butylhydroquinone treatment of RAW cells, did not increase expression of Il6. Compared to cells transduced with scrambled non-target negative control shRNA, Keap1-KD RAW cells showed enhanced protein levels of IKKβ and increased expression and phosphorylation of NF-κB p65 under non-stressed and LPS-treated conditions. Because the expression of Il6 in Keap1-KD RAW cells was significantly attenuated by silencing of Ikkβ, but not Nrf2, it appears that stabilized IKKβ is responsible for the enhanced transactivation of Il6 in Keap1-KD cells. This study demonstrated that silencing of Keap1 in macrophages boosts LPS-induced transcription of Il6 via NF-κB activation. Given the importance of IL6 in the inflammatory response, the Keap1–IKKβ–NF-κB pathway may be a novel target for treatment and prevention of inflammation and associated disorders. - Highlights: • Knockdown of Keap1 increases expression of Il6 in macrophages. • Silencing of Keap1 results in protein accumulation of IKKβ and NF-κB p65. • Induction of Il6 resulting from Keap1 silencing is attributed to NF-κB activation
Keap1 silencing boosts lipopolysaccharide-induced transcription of interleukin 6 via activation of nuclear factor κB in macrophages

Energy Technology Data Exchange (ETDEWEB)

Lv, Peng [Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Xue, Peng; Dong, Jian [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Peng, Hui [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences (China); Clewell, Rebecca [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Wang, Aiping [Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Wang, Yue [Institute for Medical Device Standardization Administration, National Institutes for Food and Drug Control, Beijing (China); Peng, Shuangqing [Evaluation and Research Center for Toxicology, Institute of Disease Control and Prevention, Academy of Military Medical Sciences (China); Qu, Weidong [Key Laboratory of the Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai (China); Zhang, Qiang; Andersen, Melvin E. [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States); Pi, Jingbo, E-mail: jpi@thehamner.org [Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC 27709 (United States)

2013-11-01

Interleukin-6 (IL6) is a multifunctional cytokine that regulates immune and inflammatory responses. Multiple transcription factors, including nuclear factor κB (NF-κB) and nuclear factor E2-related factor 2 (Nrf2), regulate IL6 transcription. Kelch-like ECH-associated protein 1 (Keap1) is a substrate adaptor protein for the Cullin 3-dependent E3 ubiquitin ligase complex, which regulates the degradation of many proteins, including Nrf2 and IκB kinase β (IKKβ). Here, we found that stable knockdown of Keap1 (Keap1-KD) in RAW 264.7 (RAW) mouse macrophages and human monocyte THP-1 cells significantly increased expression of Il6, and Nrf2-target genes, under basal and lipopolysaccharide (LPS, 0.001–0.1 μg/ml)-challenged conditions. However, Nrf2 activation alone, by tert-butylhydroquinone treatment of RAW cells, did not increase expression of Il6. Compared to cells transduced with scrambled non-target negative control shRNA, Keap1-KD RAW cells showed enhanced protein levels of IKKβ and increased expression and phosphorylation of NF-κB p65 under non-stressed and LPS-treated conditions. Because the expression of Il6 in Keap1-KD RAW cells was significantly attenuated by silencing of Ikkβ, but not Nrf2, it appears that stabilized IKKβ is responsible for the enhanced transactivation of Il6 in Keap1-KD cells. This study demonstrated that silencing of Keap1 in macrophages boosts LPS-induced transcription of Il6 via NF-κB activation. Given the importance of IL6 in the inflammatory response, the Keap1–IKKβ–NF-κB pathway may be a novel target for treatment and prevention of inflammation and associated disorders. - Highlights: • Knockdown of Keap1 increases expression of Il6 in macrophages. • Silencing of Keap1 results in protein accumulation of IKKβ and NF-κB p65. • Induction of Il6 resulting from Keap1 silencing is attributed to NF-κB activation.
Reactive oxygen species-generating mitochondrial DNA mutation up-regulates hypoxia-inducible factor-1alpha gene transcription via phosphatidylinositol 3-kinase-Akt/protein kinase C/histone deacetylase pathway.

Science.gov (United States)

Koshikawa, Nobuko; Hayashi, Jun-Ichi; Nakagawara, Akira; Takenaga, Keizo

2009-11-27

Lewis lung carcinoma-derived high metastatic A11 cells constitutively overexpress hypoxia-inducible factor (HIF)-1alpha mRNA compared with low metastatic P29 cells. Because A11 cells exclusively possess a G13997A mutation in the mitochondrial NADH dehydrogenase subunit 6 (ND6) gene, we addressed here a causal relationship between the ND6 mutation and the activation of HIF-1alpha transcription, and we investigated the potential mechanism. Using trans-mitochondrial cybrids between A11 and P29 cells, we found that the ND6 mutation was directly involved in HIF-1alpha mRNA overexpression. Stimulation of HIF-1alpha transcription by the ND6 mutation was mediated by overproduction of reactive oxygen species (ROS) and subsequent activation of phosphatidylinositol 3-kinase (PI3K)-Akt and protein kinase C (PKC) signaling pathways. The up-regulation of HIF-1alpha transcription was abolished by mithramycin A, an Sp1 inhibitor, but luciferase reporter and chromatin immunoprecipitation assays indicated that Sp1 was necessary but not sufficient for HIF-1alpha mRNA overexpression in A11 cells. On the other hand, trichostatin A, a histone deacetylase (HDAC) inhibitor, markedly suppressed HIF-1alpha transcription in A11 cells. In accordance with this, HDAC activity was high in A11 cells but low in P29 cells and in A11 cells treated with the ROS scavenger ebselene, the PI3K inhibitor LY294002, and the PKC inhibitor Ro31-8220. These results suggest that the ROS-generating ND6 mutation increases HIF-1alpha transcription via the PI3K-Akt/PKC/HDAC pathway, leading to HIF-1alpha protein accumulation in hypoxic tumor cells.
Knockdown of BAG3 induces epithelial–mesenchymal transition in thyroid cancer cells through ZEB1 activation

Science.gov (United States)

Meng, X; Kong, D-H; Li, N; Zong, Z-H; Liu, B-Q; Du, Z-X; Guan, Y; Cao, L; Wang, H-Q

2014-01-01

The process by which epithelial features are lost in favor of a mesenchymal phenotype is referred to as epithelial–mesenchymal transition (EMT). Most carcinomas use this mechanism to evade into neighboring tissues. Reduction or a loss of E-cadherin expression is a well-established hallmark of EMT. As a potent suppressor of E-cadherin, transcription factor ZEB1 is one of the key inducers of EMT, whose expression promotes tumorigenesis and metastasis of carcinomas. Bcl-2-associated athanogene 3 (BAG3) affects multifaceted cellular functions, including proliferation, apoptosis, cell adhesion and invasion, viral infection, and autophagy. Recently, we have reported a novel role of BAG3 implicated in EMT, while the mechanisms are poorly elucidated. The current study demonstrated that knockdown of BAG3 induced EMT, and increased cell migratory and invasiveness in thyroid cancer cells via transcriptional activation of ZEB1. We also found that BAG3 knockdown led to nuclear accumulation of β-catenin, which was responsible for the transcriptional activation of ZEB1. These results indicate BAG3 as a regulator of ZEB1 expression in EMT and as a regulator of metastasis in thyroid cancer cells, providing potential targets to prevent and/or treat thyroid cancer cell invasion and metastasis. PMID:24577090
Knockdown of BAG3 induces epithelial-mesenchymal transition in thyroid cancer cells through ZEB1 activation.

Science.gov (United States)

Meng, X; Kong, D-H; Li, N; Zong, Z-H; Liu, B-Q; Du, Z-X; Guan, Y; Cao, L; Wang, H-Q

2014-02-27

The process by which epithelial features are lost in favor of a mesenchymal phenotype is referred to as epithelial-mesenchymal transition (EMT). Most carcinomas use this mechanism to evade into neighboring tissues. Reduction or a loss of E-cadherin expression is a well-established hallmark of EMT. As a potent suppressor of E-cadherin, transcription factor ZEB1 is one of the key inducers of EMT, whose expression promotes tumorigenesis and metastasis of carcinomas. Bcl-2-associated athanogene 3 (BAG3) affects multifaceted cellular functions, including proliferation, apoptosis, cell adhesion and invasion, viral infection, and autophagy. Recently, we have reported a novel role of BAG3 implicated in EMT, while the mechanisms are poorly elucidated. The current study demonstrated that knockdown of BAG3 induced EMT, and increased cell migratory and invasiveness in thyroid cancer cells via transcriptional activation of ZEB1. We also found that BAG3 knockdown led to nuclear accumulation of β-catenin, which was responsible for the transcriptional activation of ZEB1. These results indicate BAG3 as a regulator of ZEB1 expression in EMT and as a regulator of metastasis in thyroid cancer cells, providing potential targets to prevent and/or treat thyroid cancer cell invasion and metastasis.
Overexpression of the transcription factor Sp1 activates the OAS-RNAse L-RIG-I pathway.

Directory of Open Access Journals (Sweden)

Valéryane Dupuis-Maurin

Full Text Available Deregulated expression of oncogenes or transcription factors such as specificity protein 1 (Sp1 is observed in many human cancers and plays a role in tumor maintenance. Paradoxically in untransformed cells, Sp1 overexpression induces late apoptosis but the early intrinsic response is poorly characterized. In the present work, we studied increased Sp1 level consequences in untransformed cells and showed that it turns on an early innate immune transcriptome. Sp1 overexpression does not activate known cellular stress pathways such as DNA damage response or endoplasmic reticulum stress, but induces the activation of the OAS-RNase L pathway and the generation of small self-RNAs, leading to the upregulation of genes of the antiviral RIG-I pathway at the transcriptional and translational levels. Finally, Sp1-induced intrinsic innate immune response leads to the production of the chemokine CXCL4 and to the recruitment of inflammatory cells in vitro and in vivo. Altogether our results showed that increased Sp1 level in untransformed cells constitutes a novel danger signal sensed by the OAS-RNase L axis leading to the activation of the RIG-I pathway. These results suggested that the OAS-RNase L-RIG-I pathway may be activated in sterile condition in absence of pathogen.
Mutational analysis of the activator of late transcription, Alt , in the lactococcal bacteriophage TP901-1

DEFF Research Database (Denmark)

Pedersen, Margit; Hammer, Karin

2007-01-01

An activator protein, Alt, synthesized during the early state of lytic infection is required for transcription of the late operon in the lactococcal phage TP901-1. In order to identify amino acid residues in the Alt protein required for activation of the TP901-1 late promoter, Plate, hydroxylamine...
Regulation of hepatic lipogenesis by the transcription complex Prep1-Pbx1

OpenAIRE

Cabaro, Serena

2011-01-01

Prep1 is an homeodomain transcription factor belonging to the TALE proteins, including also Pbx1, which plays an essential role in hematopoiesis, organogenesis and development. Prep1 forms transcriptionally active complexes with Pbx1 and regulates the activity of several genes. The Prep1 null mutation leads to embryonic death at a very early stage. Therefore, Prep1 hypomorphic (Prep1i/i) mice have been generated. Prep1 heterozygous (Prep1i/+) mice, which express only 55-57% of protein, have a...

Cisplatin Induces Cytotoxicity through the Mitogen-Activated Protein Kinase Pathways ana Activating Transcription Factor 3

Directory of Open Access Journals (Sweden)

Carly St. Germain

2010-07-01

Full Text Available The mechanisms underlying the proapoptotic effect of the chemotherapeutic agent, cisplatin, are largely undefined. Understanding the mechanisms regulating cisplatin cytotoxicity may uncover strategies to enhance the efficacy of this important therapeutic agent. This study evaluates the role of activating transcription factor 3 (ATF3 as a mediator of cisplatin-induced cytotoxicity. Cytotoxic doses of cisplatin and carboplatin treatments consistently induced ATF3 expression in five tumor-derived cell lines. Characterization of this induction revealed a p53, BRCA1, and integrated stress response-independent mechanism, all previously implicated in stress-mediated ATF3 induction. Analysis of mitogenactivated protein kinase (MAPK pathway involvement in ATF3 induction by cisplatin revealed a MAPK-dependent mechanism. Cisplatin treatment combined with specific inhibitors to each MAPK pathway (c-Jun N-terminal kinase, extracellularsignal-regulated kinase, and p38 resulted in decreasedATF3 induction at the protein level. MAPK pathway inhibition led to decreased ATF3 messenger RNA expression and reduced cytotoxic effects of cisplatin as measured by the 3-(4,5-dimethylthiazol-2-ylF2,5-diphenyltetrazolium bromide cell viability assay. In A549 lung carcinoma cells, targeting ATF3 with specific small hairpin RNA also attenuated the cytotoxic effects of cisplatin. Similarly, ATF3-/murine embryonic fibroblasts (MEFs were shown to be less sensitive to cisplatin-induced cytotoxicity compared with ATF3+/+ MEFs. This study identifies cisplatin as a MAPK pathway-dependent inducer of ATF3, whose expression influences cisplatin’s cytotoxic effects.
Epstein-Barr virus-derived EBNA2 regulates STAT3 activation

International Nuclear Information System (INIS)

Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Togi, Sumihito; Kamitani, Shinya; Fujimuro, Masahiro; Harada, Shizuko; Oritani, Kenji; Matsuda, Tadashi

2009-01-01

The Epstein-Barr virus (EBV)-encoded latency protein EBNA2 is a nuclear transcriptional activator that is essential for EBV-induced cellular transformation. Here, we show that EBNA2 interacts with STAT3, a signal transducer for an interleukin-6 family cytokine, and enhances the transcriptional activity of STAT3 by influencing its DNA-binding activity. Furthermore, EBNA2 cooperatively acts on STAT3 activation with LMP1. These data demonstrate that EBNA2 acts as a transcriptional coactivator of STAT3.
Redefining the transcriptional regulatory dynamics of classically and alternatively activated macrophages by deepCAGE transcriptomics

KAUST Repository

Roy, S.

2015-06-27

Classically or alternatively activated macrophages (M1 and M2, respectively) play distinct and important roles for microbiocidal activity, regulation of inflammation and tissue homeostasis. Despite this, their transcriptional regulatory dynamics are poorly understood. Using promoter-level expression profiling by non-biased deepCAGE we have studied the transcriptional dynamics of classically and alternatively activated macrophages. Transcription factor (TF) binding motif activity analysis revealed four motifs, NFKB1_REL_RELA, IRF1,2, IRF7 and TBP that are commonly activated but have distinct activity dynamics in M1 and M2 activation. We observe matching changes in the expression profiles of the corresponding TFs and show that only a restricted set of TFs change expression. There is an overall drastic and transient up-regulation in M1 and a weaker and more sustainable up-regulation in M2. Novel TFs, such as Thap6, Maff, (M1) and Hivep1, Nfil3, Prdm1, (M2) among others, were suggested to be involved in the activation processes. Additionally, 52 (M1) and 67 (M2) novel differentially expressed genes and, for the first time, several differentially expressed long non-coding RNA (lncRNA) transcriptome markers were identified. In conclusion, the finding of novel motifs, TFs and protein-coding and lncRNA genes is an important step forward to fully understand the transcriptional machinery of macrophage activation.
AKT activation drives the nuclear localization of CSE1L and a pro-oncogenic transcriptional activation in ovarian cancer cells

Energy Technology Data Exchange (ETDEWEB)

Lorenzato, Annalisa; Biolatti, Marta [Department of Oncology, University of Torino School of Medicine, Torino (Italy); Institute for Cancer Research at Candiolo, Candiolo, Torino (Italy); Delogu, Giuseppe [Department of Biomedical Sciences-Histology, University of Sassari, Sassari (Italy); Capobianco, Giampiero [Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari (Italy); Farace, Cristiano [Department of Biomedical Sciences-Histology, University of Sassari, Sassari (Italy); Dessole, Salvatore; Cossu, Antonio; Tanda, Francesco [Department of Surgical, Microsurgical and Medical Sciences, University of Sassari, Sassari (Italy); Madeddu, Roberto [Department of Biomedical Sciences-Histology, University of Sassari, Sassari (Italy); National Institute of Biostructures and Biosystems, Rome (Italy); Olivero, Martina [Department of Oncology, University of Torino School of Medicine, Torino (Italy); Institute for Cancer Research at Candiolo, Candiolo, Torino (Italy); Di Renzo, Maria Flavia, E-mail: mariaflavia.direnzo@unito.it [Department of Oncology, University of Torino School of Medicine, Torino (Italy); Institute for Cancer Research at Candiolo, Candiolo, Torino (Italy)

2013-10-15

The human homolog of the yeast cse1 gene (CSE1L) is over-expressed in ovarian cancer. CSE1L forms complex with Ran and importin-α and has roles in nucleocytoplasmic traffic and gene expression. CSE1L accumulated in the nucleus of ovarian cancer cell lines, while it was localized also in the cytoplasm of other cancer cell lines. Nuclear localization depended on AKT, which was constitutively active in ovarian cancer cells, as the CSE1L protein translocated to the cytoplasm when AKT was inactivated. Moreover, the expression of a constitutively active AKT forced the translocation of CSE1L from the cytoplasm to the nucleus in other cancer cells. Nuclear accrual of CSE1L was associated to the nuclear accumulation of the phosphorylated Ran Binding protein 3 (RanBP3), which depended on AKT as well. Also in samples of human ovarian cancer, AKT activation was associated to nuclear accumulation of CSE1L and phosphorylation of RanBP3. Expression profiling of ovarian cancer cells after CSE1L silencing showed that CSE1L was required for the expression of genes promoting invasion and metastasis. In agreement, CSE1L silencing impaired motility and invasiveness of ovarian cancer cells. Altogether these data show that in ovarian cancer cells activated AKT by affecting RanBP3 phosphorylation determines the nuclear accumulation of CSE1L and likely the nuclear concentration of transcription factors conveying pro-oncogenic signals. - highlights: • CSE1L is a key player in nucleocytoplasmic traffic by forming complex with Ran. • AKT phosphorylates RanBP3 that regulates the nucleocytoplasmic gradient of Ran. • The activated oncogenic AKT drives the nuclear accumulation of CSE1L. • CSE1L in the nucleus up-regulates genes conveying pro-oncogenic signals. • CSE1L might contribute to tumor progression driven by the activated oncogenic AKT.
AKT activation drives the nuclear localization of CSE1L and a pro-oncogenic transcriptional activation in ovarian cancer cells

International Nuclear Information System (INIS)

Lorenzato, Annalisa; Biolatti, Marta; Delogu, Giuseppe; Capobianco, Giampiero; Farace, Cristiano; Dessole, Salvatore; Cossu, Antonio; Tanda, Francesco; Madeddu, Roberto; Olivero, Martina; Di Renzo, Maria Flavia

2013-01-01

The human homolog of the yeast cse1 gene (CSE1L) is over-expressed in ovarian cancer. CSE1L forms complex with Ran and importin-α and has roles in nucleocytoplasmic traffic and gene expression. CSE1L accumulated in the nucleus of ovarian cancer cell lines, while it was localized also in the cytoplasm of other cancer cell lines. Nuclear localization depended on AKT, which was constitutively active in ovarian cancer cells, as the CSE1L protein translocated to the cytoplasm when AKT was inactivated. Moreover, the expression of a constitutively active AKT forced the translocation of CSE1L from the cytoplasm to the nucleus in other cancer cells. Nuclear accrual of CSE1L was associated to the nuclear accumulation of the phosphorylated Ran Binding protein 3 (RanBP3), which depended on AKT as well. Also in samples of human ovarian cancer, AKT activation was associated to nuclear accumulation of CSE1L and phosphorylation of RanBP3. Expression profiling of ovarian cancer cells after CSE1L silencing showed that CSE1L was required for the expression of genes promoting invasion and metastasis. In agreement, CSE1L silencing impaired motility and invasiveness of ovarian cancer cells. Altogether these data show that in ovarian cancer cells activated AKT by affecting RanBP3 phosphorylation determines the nuclear accumulation of CSE1L and likely the nuclear concentration of transcription factors conveying pro-oncogenic signals. - highlights: • CSE1L is a key player in nucleocytoplasmic traffic by forming complex with Ran. • AKT phosphorylates RanBP3 that regulates the nucleocytoplasmic gradient of Ran. • The activated oncogenic AKT drives the nuclear accumulation of CSE1L. • CSE1L in the nucleus up-regulates genes conveying pro-oncogenic signals. • CSE1L might contribute to tumor progression driven by the activated oncogenic AKT
Transcriptional effects of 1,25 dihydroxyvitamin D3 physiological and supra-physiological concentrations in breast cancer organotypic culture

International Nuclear Information System (INIS)

Milani, Cintia; Góes, João Carlos Guedes Sampaio; Nonogaki, Suely; Tamura, Rodrigo Esaki; Folgueira, Maria Aparecida Azevedo Koike; Katayama, Maria Lucia Hirata; Lyra, Eduardo Carneiro de; Welsh, JoEllen; Campos, Laura Tojeiro; Brentani, M Mitzi; Maciel, Maria do Socorro; Roela, Rosimeire Aparecida; Valle, Paulo Roberto del

2013-01-01

epithelial cells and CA2 and DPP4 in CAFs exposed to 1,25(OH) 2 D 3 0.5nM was detected. In breast cancer specimens a short period of 1,25(OH) 2 D 3 exposure at near physiological concentration modestly activates the hormone transcriptional pathway. Induction of CYP24A1, CA2, DPP4, IL1RL1 expression appears to reflect 1,25(OH) 2 D 3 effects in epithelial as well as stromal cells, however, induction of CD14 expression is likely restricted to the epithelial compartment
Direct assessment of the effect of the Gly380Arg achondroplasia mutation on FGFR3 dimerization using quantitative imaging FRET.

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Jesse Placone

Full Text Available The Gly380Arg mutation in FGFR3 is the genetic cause for achondroplasia (ACH, the most common form of human dwarfism. The mutation has been proposed to increase FGFR3 dimerization, but the dimerization propensities of wild-type and mutant FGFR3 have not been compared. Here we use quantitative imaging FRET to characterize the dimerization of wild-type FGFR3 and the ACH mutant in plasma membrane-derived vesicles from HEK293T cells. We demonstrate a small, but statistically significant increase in FGFR3 dimerization due to the ACH mutation. The data are consistent with the idea that the ACH mutation causes a structural change which affects both the stability and the activity of FGFR3 dimers in the absence of ligand.
Post-transcription cleavage generates the 3' end of F17R transcripts in vaccinia virus

International Nuclear Information System (INIS)

D'Costa, Susan M.; Antczak, James B.; Pickup, David J.; Condit, Richard C.

2004-01-01

Most vaccinia virus intermediate and late mRNAs possess 3' ends that are extremely heterogeneous in sequence. However, late mRNAs encoding the cowpox A-type inclusion protein (ATI), the second largest subunit of the RNA polymerase, and the late telomeric transcripts possess homogeneous 3' ends. In the case of the ATI mRNA, it has been shown that the homogeneous 3' end is generated by a post-transcriptional endoribonucleolytic cleavage event. We have determined that the F17R gene also produces homogeneous transcripts generated by a post-transcriptional cleavage event. Mapping of in vivo mRNA shows that the major 3' end of the F17R transcript maps 1262 nt downstream of the F17R translational start site. In vitro transcripts spanning the in vivo 3' end are cleaved in an in vitro reaction using extracts from virus infected cells, and the site of cleavage is the same both in vivo and in vitro. Cleavage is not observed using extract from cells infected in the presence of hydroxyurea; therefore, the cleavage factor is either virus-coded or virus-induced during the post-replicative phase of virus replication. The cis-acting sequence responsible for cleavage is orientation specific and the factor responsible for cleavage activity has biochemical properties similar to the factor required for cleavage of ATI transcripts. Partially purified cleavage factor generates cleavage products of expected size when either the ATI or F17R substrates are used in vitro, strongly suggesting that cleavage of both transcripts is mediated by the same factor
Kirenol inhibits adipogenesis through activation of the Wnt/β-catenin signaling pathway in 3T3-L1 adipocytes

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Kim, Mi-Bo [Department of Biomaterials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Song, Youngwoo; Kim, Changhee [Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Hwang, Jae-Kwan, E-mail: jkhwang@yonsei.ac.kr [Department of Biomaterials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of)

2014-03-07

Highlights: • Kirenol inhibits the adipogenic transcription factors and lipogenic enzymes. • Kirenol stimulates the Wnt/β-catenin signaling pathway components. • Kirenol inhibits adipogenesis through activation of the Wnt/β-catenin signaling pathway. - Abstract: Kirenol, a natural diterpenoid compound, has been reported to possess anti-oxidant, anti-inflammatory, anti-allergic, and anti-arthritic activities; however, its anti-adipogenic effect remains to be studied. The present study evaluated the effect of kirenol on anti-adipogenesis through the activation of the Wnt/β-catenin signaling pathway. Kirenol prevented intracellular lipid accumulation by down-regulating key adipogenesis transcription factors [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding proteins α (C/EBPα), and sterol regulatory element binding protein-1c (SREBP-1c)] and lipid biosynthesis-related enzymes [fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC)], as well as adipocytokines (adiponectin and leptin). Kirenol effectively activated the Wnt/β-catenin signaling pathway, in which kirenol up-regulated the expression of low density lipoprotein receptor related protein 6 (LRP6), disheveled 2 (DVL2), β-catenin, and cyclin D1 (CCND1), while it inactivated glycogen synthase kinase 3β (GSK3β) by increasing its phosphorylation. Kirenol down-regulated the expression levels of PPARγ and C/EBPα, which were up-regulated by siRNA knockdown of β-catenin. Overall, kirenol is capable of inhibiting the differentiation and lipogenesis of 3T3-L1 adipocytes through the activation of the Wnt/β-catenin signaling pathway, suggesting its potential as natural anti-obesity agent.
Prognostic value of hedgehog signaling pathway in digestive system cancers: A systematic review and meta-analysis.

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Wang, Yihan; Peng, Qian; Jia, Hongyuan; Du, Xiao

2016-01-01

The Hedgehog (Hh) signaling pathway has recently been reported to be associated with the prognosis of digestive system cancers. However, the results are inconsistent. This study aimed to investigate the association between Hh pathway components and survival outcomes in patients with digestive system cancers. We conducted a comprehensive retrieval in PubMed, EMBASE and Cochrane library for relevant literatures until May 1st, 2015. The pooled hazard ratios (HRs) for overall survival (OS) and disease-free survival (DFS) with 95% confidence intervals (CIs) were calculated to clarify the prognostic value of Hh pathway components, including Shh, Gli1, Gli2, Smo and Ptch1. A total of 16 eligible articles with 3222 patients were included in the meta-analysis. Pooled HR suggested that over-expression of Shh and Gli1 were both associated with poor OS (HR = 1.87, 95% CI: 1.14-3.07 and HR = 1.96, 95% CI: 1.66-2.32, respectively) and DFS (HR = 2.37, 95% CI: 1.19-4.72 and HR = 2.18, 95% CI: 1.61-2.96, respectively). In addition, over-expression of Smo was associated with poor DFS (HR = 1.38, 95% CI: 1.08-1.75). This study reveals that over-expressed Hh pathway components, including Shh, Gli1 and Smo, are associated with poor prognosis in digestive system cancer patients. Hh signaling pathway may become a potential therapeutic target in digestive system cancers.
BASP1 is a transcriptional cosuppressor for the Wilms' tumor suppressor protein WT1

DEFF Research Database (Denmark)

Carpenter, Brian; Hill, Kathryn J; Charalambous, Marika

2004-01-01

The Wilms' tumor suppressor protein WT1 is a transcriptional regulator that plays a key role in the development of the kidneys. The transcriptional activation domain of WT1 is subject to regulation by a suppression region within the N terminus of WT1. Using a functional assay, we provide direct...... evidence that this requires a transcriptional cosuppressor, which we identify as brain acid soluble protein 1 (BASP1). WT1 and BASP1 associate within the nuclei of cells that naturally express both proteins. BASP1 can confer WT1 cosuppressor activity in transfection assays, and elimination of endogenous...
Iron chelators ICL670 and 311 inhibit HIV-1 transcription

International Nuclear Information System (INIS)

Debebe, Zufan; Ammosova, Tatyana; Jerebtsova, Marina; Kurantsin-Mills, Joseph; Niu, Xiaomei; Charles, Sharroya; Richardson, Des R.; Ray, Patricio E.; Gordeuk, Victor R.; Nekhai, Sergei

2007-01-01

HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics
Sumoylation of the net inhibitory domain (NID) is stimulated by PIAS1 and has a negative effect on the transcriptional activity of Net.

Science.gov (United States)

Wasylyk, Christine; Criqui-Filipe, Paola; Wasylyk, Bohdan

2005-01-27

Net (Elk-3, Sap-2, Erp) and the related ternary complex factors Elk-1 and Sap-1 are effectors of multiple signalling pathways at the transcriptional level and play a key role in the dynamic regulation of gene expression. Net is distinct from Elk-1 and Sap-1, in that it is a strong repressor of transcription that is converted to an activator by the Ras/Erk signalling pathway. Two autonomous repression domains of Net, the NID and the CID, mediate repression. We have previously shown that the co-repressor CtBP is implicated in repression by the CID. In this report we show that repression by the NID involves a different pathway, sumoylation by Ubc9 and PIAS1. PIAS1 interacts with the NID in the two-hybrid assay and in vitro. Ubc9 and PIAS1 stimulate sumoylation in vivo of lysine 162 in the NID. Sumoylation of lysine 162 increases repression by Net and decreases the positive activity of Net. These results increase our understanding of how one of the ternary complex factors regulates transcription, and contribute to the understanding of how different domains of a transcription factor participate in the complexity of regulation of gene expression.
Sonic hedgehog signaling regulates actin cytoskeleton via Tiam1-Rac1 cascade during spine formation.

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Sasaki, Nobunari; Kurisu, Junko; Kengaku, Mineko

2010-12-01

The sonic hedgehog (Shh) pathway has essential roles in several processes during development of the vertebrate central nervous system (CNS). Here, we report that Shh regulates dendritic spine formation in hippocampal pyramidal neurons via a novel pathway that directly regulates the actin cytoskeleton. Shh signaling molecules Patched (Ptc) and Smoothened (Smo) are expressed in several types of postmitotic neurons, including cerebellar Purkinje cells and hippocampal pyramidal neurons. Knockdown of Smo induces dendritic spine formation in cultured hippocampal neurons independently of Gli-mediated transcriptional activity. Smo interacts with Tiam1, a guanine nucleotide exchange factor for Rac1, via its cytoplasmic C-terminal region. Inhibition of Tiam1 or Rac1 activity suppresses spine induction by Smo knockdown. Shh induces remodeling of the actin cytoskeleton independently of transcriptional activation in mouse embryonic fibroblasts. These findings demonstrate a novel Shh pathway that regulates the actin cytoskeleton via Tiam1-Rac1 activation. Copyright © 2010 Elsevier Inc. All rights reserved.
Histone acetyltransferase (HAT) activity of p300 modulates human T lymphotropic virus type 1 p30II-mediated repression of LTR transcriptional activity

International Nuclear Information System (INIS)

Michael, Bindhu; Nair, Amrithraj M.; Datta, Antara; Hiraragi, Hajime; Ratner, Lee; Lairmore, Michael D.

2006-01-01

Human T-lymphotropic virus type-1 (HTLV-1) is a deltaretrovirus that causes adult T cell leukemia/lymphoma, and is implicated in a variety of lymphocyte-mediated inflammatory disorders. HTLV-1 provirus has regulatory and accessory genes in four pX open reading frames. HTLV-1 pX ORF-II encodes two proteins, p13 II and p30 II , which are incompletely defined in virus replication or pathogenesis. We have demonstrated that pX ORF-II mutations block virus replication in vivo and that ORF-II encoded p30 II , a nuclear-localizing protein that binds with CREB-binding protein (CBP)/p300, represses CREB and Tax responsive element (TRE)-mediated transcription. Herein, we have identified p30 II motifs important for p300 binding and in regulating TRE-mediated transcription in the absence and presence of HTLV-1 provirus. Within amino acids 100-179 of p30 II , a region important for repression of LTR-mediated transcription, we identified a single lysine residue at amino acid 106 (K3) that significantly modulates the ability of p30 II to repress TRE-mediated transcription. Exogenous p300, in a dose-responsive manner, reverses p30 II -dependent repression of TRE-mediated transcription, in the absence or presence of the provirus, In contrast to wild type p300, p300 HAT mutants (defective in histone acetyltransferase activity) only partially rescued p30 II -mediated LTR repression. Deacetylation by histone deacetylase-1 (HDAC-1) enhanced p30 II -mediated LTR repression, while inhibition of deacetylation by trichostatin A decreases p30 II -mediated LTR repression. Collectively, our data indicate that HTLV-1 p30 II modulates viral gene expression in a cooperative manner with p300-mediated acetylation
Transcription factor HBP1 is a direct anti-cancer target of transcription factor FOXO1 in invasive oral cancer.

Science.gov (United States)

Chan, Chien-Yi; Huang, Shih-Yi; Sheu, Jim Jinn-Chyuan; Roth, Mendel M; Chou, I-Tai; Lien, Chia-Hsien; Lee, Ming-Fen; Huang, Chun-Yin

2017-02-28

Either FOXO1 or HBP1 transcription factor is a downstream effector of the PI3K/Akt pathway and associated with tumorigenesis. However, the relationship between FOXO1 and HBP1 in oral cancer remains unclear. Analysis of 30 oral tumor specimens revealed that mean mRNA levels of both FOXO1 and HBP1 in non-invasive and invasive oral tumors were found to be significantly lower than that of the control tissues, and the status of low FOXO1 and HBP1 (oral tumors. To investigate if HBP1 is a direct transcription target of FOXO1, we searched potential FOXO1 binding sites in the HBP1 promoter using the MAPPER Search Engine, and two putative FOXO1 binding sites located in the HBP1 promoter -132 to -125 bp and -343 to -336 bp were predicted. These binding sites were then confirmed by both reporter gene assays and the in cellulo ChIP assay. In addition, Akt activity manipulated by PI3K inhibitor LY294002 or Akt mutants was shown to negatively affect FOXO1-mediated HBP1 promoter activation and gene expression. Last, the biological significance of the FOXO1-HBP1 axis in oral cancer malignancy was evaluated in cell growth, colony formation, and invasiveness. The results indicated that HBP1 knockdown potently promoted malignant phenotypes of oral cancer and the suppressive effect of FOXO1 on cell growth, colony formation, and invasion was alleviated upon HBP1 knockdown in invasive oral cancer cells. Taken together, our data provide evidence for HBP1 as a direct downstream target of FOXO1 in oral cancer malignancy.
Changes in signal transducer and activator of transcription 3 (STAT3) dynamics induced by complexation with pharmacological inhibitors of Src homology 2 (SH2) domain dimerization.

Science.gov (United States)

Resetca, Diana; Haftchenary, Sina; Gunning, Patrick T; Wilson, Derek J

2014-11-21

The activity of the transcription factor signal transducer and activator of transcription 3 (STAT3) is dysregulated in a number of hematological and solid malignancies. Development of pharmacological STAT3 Src homology 2 (SH2) domain interaction inhibitors holds great promise for cancer therapy, and a novel class of salicylic acid-based STAT3 dimerization inhibitors that includes orally bioavailable drug candidates has been recently developed. The compounds SF-1-066 and BP-1-102 are predicted to bind to the STAT3 SH2 domain. However, given the highly unstructured and dynamic nature of the SH2 domain, experimental confirmation of this prediction was elusive. We have interrogated the protein-ligand interaction of STAT3 with these small molecule inhibitors by means of time-resolved electrospray ionization hydrogen-deuterium exchange mass spectrometry. Analysis of site-specific evolution of deuterium uptake induced by the complexation of STAT3 with SF-1-066 or BP-1-102 under physiological conditions enabled the mapping of the in silico predicted inhibitor binding site to the STAT3 SH2 domain. The binding of both inhibitors to the SH2 domain resulted in significant local decreases in dynamics, consistent with solvent exclusion at the inhibitor binding site and increased rigidity of the inhibitor-complexed SH2 domain. Interestingly, inhibitor binding induced hot spots of allosteric perturbations outside of the SH2 domain, manifesting mainly as increased deuterium uptake, in regions of STAT3 important for DNA binding and nuclear localization. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
Set1/COMPASS and Mediator are repurposed to promote epigenetic transcriptional memory.

Science.gov (United States)

D'Urso, Agustina; Takahashi, Yoh-Hei; Xiong, Bin; Marone, Jessica; Coukos, Robert; Randise-Hinchliff, Carlo; Wang, Ji-Ping; Shilatifard, Ali; Brickner, Jason H

2016-06-23

In yeast and humans, previous experiences can lead to epigenetic transcriptional memory: repressed genes that exhibit mitotically heritable changes in chromatin structure and promoter recruitment of poised RNA polymerase II preinitiation complex (RNAPII PIC), which enhances future reactivation. Here, we show that INO1 memory in yeast is initiated by binding of the Sfl1 transcription factor to the cis-acting Memory Recruitment Sequence, targeting INO1 to the nuclear periphery. Memory requires a remodeled form of the Set1/COMPASS methyltransferase lacking Spp1, which dimethylates histone H3 lysine 4 (H3K4me2). H3K4me2 recruits the SET3C complex, which plays an essential role in maintaining this mark. Finally, while active INO1 is associated with Cdk8(-) Mediator, during memory, Cdk8(+) Mediator recruits poised RNAPII PIC lacking the Kin28 CTD kinase. Aspects of this mechanism are generalizable to yeast and conserved in human cells. Thus, COMPASS and Mediator are repurposed to promote epigenetic transcriptional poising by a highly conserved mechanism.
Galectin-3 facilitates cell motility in gastric cancer by up-regulating protease-activated receptor-1 (PAR-1 and matrix metalloproteinase-1 (MMP-1.

Directory of Open Access Journals (Sweden)

Seok-Jun Kim

Full Text Available BACKGROUND: Galectin-3 is known to regulate cancer metastasis. However, the underlying mechanism has not been defined. Through the DNA microarray studies after galectin-3 silencing, we demonstrated here that galectin-3 plays a key role in up-regulating the expressions of protease-activated receptor-1 (PAR-1 and matrix metalloproteinase-1 (MMP-1 PAR-1 thereby promoting gastric cancer metastasis. METHODOLOGY/PRINCIPAL FINDINGS: We examined the expression levels of Galectin-3, PAR-1, and MMP-1 in gastric cancer patient tissues and also the effects of silencing these proteins with specific siRNAs and of over-expressing them using specific lenti-viral constructs. We also employed zebrafish embryo model for analysis of in vivo gastric cancer cell invasion. These studies demonstrated that: a galectin-3 silencing decreases the expression of PAR-1. b galectin-3 over-expression increases cell migration and invasion and this increase can be reversed by PAR-1 silencing, indicating that galectin-3 increases cell migration and invasion via PAR-1 up-regulation. c galectin-3 directly interacts with AP-1 transcriptional factor, and this complex binds to PAR-1 promoter and drives PAR-1 transcription. d galectin-3 also amplifies phospho-paxillin, a PAR-1 downstream target, by increasing MMP-1 expression. MMP-1 silencing blocks phospho-paxillin amplification and cell invasion caused by galectin-3 over-expression. e Silencing of either galectin-3, PAR-1 or MMP-1 significantly reduced cell migration into the vessels in zebrafish embryo model. f Galectin-3, PAR-1, and MMP-1 are highly expressed and co-localized in malignant tissues from gastric cancer patients. CONCLUSIONS/SIGNIFICANCE: Galectin-3 plays the key role of activating cell surface receptor through production of protease and boosts gastric cancer metastasis. Galectin-3 has the potential to serve as a useful pharmacological target for prevention of gastric cancer metastasis.
Insulin induces a transcriptional activation of epiregulin, HB-EGF and amphiregulin, by a PI3K-dependent mechanism: Identification of a specific insulin-responsive promoter element

International Nuclear Information System (INIS)

Ornskov, Dorthe; Nexo, Ebba; Sorensen, Boe S.

2007-01-01

Previously we have shown that insulin-stimulation of RT4 bladder cancer cells leads to increased proliferation, which require HER1 activation, and is accompanied by increased mRNA expression of the EGF-ligands heparin-binding EGF-like growth factor (HB-EGF), amphiregulin (AR), and epiregulin (EPI) [D. Ornskov, E. Nexo, B.S. Sorensen, Insulin-induced proliferation of bladder cancer cells is mediated through activation of the epidermal growth factor system, FEBS J. 273 (2006) 5479-5489]. In the present paper, we have investigated the molecular mechanism leading to this insulin-induced expression. We monitored the decay of mRNA after inhibiting transcription with Actinomycin D and demonstrated that the insulin-mediated increase was not caused by enhanced mRNA stability. In untreated cells, HB-EGF mRNA was the least stable, whereas AR and EPI mRNA decayed with slower kinetics. However, promoter analysis of HB-EGF and EPI demonstrated that insulin stimulated transcription. Studies on the EPI promoter identified the insulin-responsive element to be located in the region -564 to -365 bp. This region contains potential binding sites for the transcription factors SP1, AP1, and NF-κB. Interestingly, all three transcription factors can be activated by PI3K. We demonstrate that the insulin-induced expression of HB-EGF, AR, and EPI mRNA is completely prevented by the specific PI3K inhibitor Wortmannin, suggesting an involvement of the PI3K

The intracellular immune receptor Rx1 regulates the DNA-binding activity of a Golden2-like transcription factor

NARCIS (Netherlands)

Townsend, Philip D.; Dixon, Christopher H.; Slootweg, Erik J.; Sukarta, Octavina C.A.; Yang, Ally W.H.; Hughes, Timothy R.; Sharples, Gary J.; Palsson, Lars-Olof; Takken, Frank L.W.; Goverse, Aska; Cann, Martin J.

2018-01-01

Plant NLR proteins enable the immune system to recognise and respond to pathogen attack. An early consequence of immune activation is transcriptional reprogramming and some NLRs have been shown to act in the nucleus and interact with transcription factors. The Rx1 NLR protein of potato is further
The fruits of Gleditsia sinensis Lam. inhibits adipogenesis through modulation of mitotic clonal expansion and STAT3 activation in 3T3-L1 cells.

Science.gov (United States)

Lee, Ji-Hye; Go, Younghoon; Lee, Bonggi; Hwang, Youn-Hwan; Park, Kwang Il; Cho, Won-Kyung; Ma, Jin Yeul

2018-08-10

Gleditsia sinensis Lam. (G. sinensis) has been used in Oriental medicine for tumor, thrombosis, inflammation-related disease, and obesity. The pharmacological inhibitory effects of fruits of G. sinensis (GFE) on hyperlipidemia have been reported, but its inhibitory effects on adipogenesis and underlying mechanisms have not been elucidated. Herein we evaluated the anti-adipogenic effects of GFE and described the underlying mechanisms. The effects of ethanol extracts of GFE on adipocyte differentiation were examined in 3T3-L1 cells using biochemical and molecular analyses. During the differentiation of 3T3-L1 cells, GFE significantly reduced lipid accumulation and downregulated master adipogenic transcription factors, including CCAAT/enhancer-binding protein-α and peroxisome proliferator-activated receptor-γ, at mRNA and protein levels. These changes led to the suppression of several adipogenic-specific genes and proteins, including fatty acid synthase, sterol regulatory element-binding protein 1, stearoyl-CoA desaturase-1, and acetyl CoA carboxylase. However, the inhibitory effects of GFE on lipogenesis were only shown when GFE is treated in the early stage of adipogenesis within the first two days of differentiation. As a potential mechanism, during the early stages of differentiation, GFE inhibited cell proliferation by a decrease in the expression of DNA synthesis-related proteins and increased p27 expression and suppressed signal transducer and activator of transcription 3 (STAT3) activation induced in a differentiation medium. GFE inhibits lipogenesis by negative regulation of adipogenic transcription factors, which is associated with GFE-mediated cell cycle arrest and STAT3 inhibition. Copyright © 2018 Elsevier B.V. All rights reserved.
Tat-dependent repression of human immunodeficiency virus type 1 long terminal repeat promoter activity by fusion of cellular transcription factors

International Nuclear Information System (INIS)

Zhao Cunyou; Chen Yali; Park, Jiyoung; Kim, Jae Bum; Tang Hong

2004-01-01

Transcription initiation from HIV-1 long terminal repeat (LTR) promoter requires the virally encoded transactivator, Tat, and several cellular co-factors to accomplish the Tat-dependent processive transcription elongation. Individual cellular transcription activators, LBP-1b and Oct-1, on the other hand, have been shown to inhibit LTR promoter activities probably via competitive binding against TFIID to the TATA-box in LTR promoter. To explore the genetic interference strategies against the viral replication, we took advantage of the existence of the bipartite DNA binding domains and the repression domains of LBP-1b and Oct-1 factors to generate a chimeric transcription repressor. Our results indicated that the fusion protein of LBP-1b and Oct-1 exhibited higher DNA binding affinity to the viral promoter than the individual factors, and little interference with the host cell gene expression due to its anticipated rare cognate DNA sites in the host cell genome. Moreover, the chimera exerted increased Tat-dependent repression of transcription initiation at the LTR promoter both in vitro and in vivo compared to LBP-1b, Oct-1 or combination of LBP-1b and Oct-1. These results might provide the lead in generating a therapeutic reagent useful to suppress HIV-1 replication
Glycogen synthase kinase 3 regulates expression of nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) and inhibits pro-survival function of Nrf1

Energy Technology Data Exchange (ETDEWEB)

Biswas, Madhurima; Kwong, Erick K.; Park, Eujean; Nagra, Parminder; Chan, Jefferson Y., E-mail: jchan@uci.edu

2013-08-01

Nuclear factor E2-related factor-1 (Nrf1) is a basic leucine zipper transcription factor that is known to regulate antioxidant and cytoprotective gene expression. It was recently shown that Nrf1 is regulated by SCF–Fbw7 ubiquitin ligase. However our knowledge of upstream signals that targets Nrf1 for degradation by the UPS is not known. We report here that Nrf1 expression is negatively regulated by glycogen synthase kinase 3 (GSK3) in Fbw7-dependent manner. We show that GSK3 interacts with Nrf1 and phosphorylates the Cdc4 phosphodegron domain (CPD) in Nrf1. Mutation of serine residue in the CPD of Nrf1 to alanine (S350A), blocks Nrf1 from phosphorylation by GSK3, and stabilizes Nrf1. Knockdown of Nrf1 and expression of a constitutively active form of GSK3 results in increased apoptosis in neuronal cells in response to ER stress, while expression of the GSK3 phosphorylation resistant S350A–Nrf1 attenuates apoptotic cell death. Together these data suggest that GSK3 regulates Nrf1 expression and cell survival function in response to stress activation. Highlights: • The effect of GSK3 on Nrf1 expression was examined. • GSK3 destabilizes Nrf1 protein via Fbw7 ubiquitin ligase. • GSK3 binds and phosphorylates Nrf1. • Protection from stress-induced apoptosis by Nrf1 is inhibited by GSK3.
Data on the purification and crystallization of the loss-of-function von Willebrand disease variant (p.Gly1324Ser of the von Willebrand factor A1 domain

Directory of Open Access Journals (Sweden)

James C. Cambell

2016-06-01

In this data article we describe the production, quality control and crystallization of the p.Gly1324Ser vWD variant of the A1 domain of VWF. p.Gly1324Ser A1 was expressed in Escherichia coli as insoluble inclusion bodies. After the preparation of the inclusion bodies, the protein was solubilized, refolded, purified by affinity chromatography and crystallized. The crystal structure of the p.Gly1324Ser mutant of the A1 domain is deposited at the Protein Data Bank PDB: 5BV8
Mutation of the conserved Gly94 and Gly126 in elongation factor Tu from Escherichia coli. Elucidation of their structural and functional roles

DEFF Research Database (Denmark)

Knudsen, Charlotte Rohde; Kjaersgård, I V; Wiborg, O

1995-01-01

All guanine-nucleotide-binding proteins cycle between an inactive, GDP-bound and an active, GTP-bound conformation whereby they function as molecular switches. Elongation factor Tu from Escherichia coli is used as a model for defining residues important in the switch mechanism. Gly94 and Gly126...... were separately mutated to alanine residues to study their role in the switch mechanism. The mutant proteins are denoted [G94A]EF-Tu and [G126A]EF-Tu, respectively. Both mutations affect the affinities for guanine nucleotides considerably, resulting in a decrease in the characteristic preference...... for GDP over GTP. Furthermore the [G94A]EF-Tu mutant possesses an increased GTPase activity. The aminoacyl-tRNA affinity is much reduced for [G94A]EF-Tu, as reflected in an increase of the dissociation rate constant for the ternary complex by a factor of 40. Surprisingly, however, both mutants...
Transcriptionally Active Heterochromatin in Rye B Chromosomes[W

Science.gov (United States)

Carchilan, Mariana; Delgado, Margarida; Ribeiro, Teresa; Costa-Nunes, Pedro; Caperta, Ana; Morais-Cecílio, Leonor; Jones, R. Neil; Viegas, Wanda; Houben, Andreas

2007-01-01

B chromosomes (Bs) are dispensable components of the genomes of numerous species. Thus far, there is a lack of evidence for any transcripts of Bs in plants, with the exception of some rDNA sequences. Here, we show that the Giemsa banding-positive heterochromatic subterminal domain of rye (Secale cereale) Bs undergoes decondensation during interphase. Contrary to the heterochromatic regions of A chromosomes, this domain is simultaneously marked by trimethylated H3K4 and by trimethylated H3K27, an unusual combination of apparently conflicting histone modifications. Notably, both types of B-specific high copy repeat families (E3900 and D1100) of the subterminal domain are transcriptionally active, although with different tissue type–dependent activity. No small RNAs were detected specifically for the presence of Bs. The lack of any significant open reading frame and the highly heterogeneous size of mainly polyadenylated transcripts indicate that the noncoding RNA may function as structural or catalytic RNA. PMID:17586652
Eukaryotic translation initiator protein 1A isoform, CCS-3, enhances the transcriptional repression of p21CIP1 by proto-oncogene FBI-1 (Pokemon/ZBTB7A).

Science.gov (United States)

Choi, Won-Il; Kim, Youngsoo; Kim, Yuri; Yu, Mi-young; Park, Jungeun; Lee, Choong-Eun; Jeon, Bu-Nam; Koh, Dong-In; Hur, Man-Wook

2009-01-01

FBI-1, a member of the POK (POZ and Kruppel) family of transcription factors, plays a role in differentiation, oncogenesis, and adipogenesis. eEF1A is a eukaryotic translation elongation factor involved in several cellular processes including embryogenesis, oncogenic transformation, cell proliferation, and cytoskeletal organization. CCS-3, a potential cervical cancer suppressor, is an isoform of eEF1A. We found that eEF1A forms a complex with FBI-1 by co-immunoprecipitation, SDS-PAGE, and MALDI-TOF Mass analysis of the immunoprecipitate. GST fusion protein pull-downs showed that FBI-1 directly interacts with eEF1A and CCS-3 via the zinc finger and POZ-domain of FBI-1. FBI-1 co-localizes with either eEF1A or CCS-3 at the nuclear periplasm. CCS-3 enhances transcriptional repression of the p21CIP1 gene (hereafter referred to as p21) by FBI-1. The POZ-domain of FBI-1 interacts with the co-repressors, SMRT and BCoR. We found that CCS-3 also interacts with the co-repressors independently. The molecular interaction between the co-repressors and CCS-3 at the POZ-domain of FBI-1 appears to enhance FBI-1 mediated transcriptional repression. Our data suggest that CCS-3 may be important in cell differentiation, tumorigenesis, and oncogenesis by interacting with the proto-oncogene FBI-1 and transcriptional co-repressors. Copyright 2009 S. Karger AG, Basel.
Signal Transducer and Activator of Transcription 1 (STAT1) Knock-down Induces Apoptosis in Malignant Pleural Mesothelioma.

Science.gov (United States)

Arzt, Lisa; Halbwedl, Iris; Gogg-Kamerer, Margit; Popper, Helmut H

2017-07-01

Malignant pleural mesothelioma (MPM) is the most common primary tumor of the pleura. Its incidence is still increasing in Europe and the prognosis remains poor. We investigated the oncogenic function of signal transducer and activator of transcription 1 (STAT1) in MPM in more detail. A miRNA profiling was performed on 52 MPM tissue samples. Upregulated miRNAs (targeting SOCS1/3) were knocked-down using miRNA inhibitors. mRNA expression levels of STAT1/3, SOCS1/3 were detected in MPM cell lines. STAT1 has been knocked-down using siRNA and qPCR was used to detect mRNA expression levels of all JAK/STAT family members and genes that regulate them. An immunohistochemical staining was performed to detect the expression of caspases. STAT1 was upregulated and STAT3 was downregulated, SOCS1/3 protein was not detected but it was possible to detect SOCS1/3 mRNA in MPM cell lines. The upregulated miRNAs were successfully knocked-down, however the expected effect on SOCS1 expression was not detected. STAT1 knock-down had different effects on STAT3/5 expression. Caspase 3a and 8 expression was found to be increased after STAT1 knock-down. The physiologic regulation of STAT1 via SOCS1 is completely lost in MPM and it does not seem that the miRNAs identified by now, do inhibit the expression of SOCS1. MPM cell lines compensate STAT1 knock-down by increasing the expression of STAT3 or STAT5a, two genes which are generally considered to be oncogenes. And much more important, STAT1 knock-down induces apoptosis in MPM cell lines and STAT1 might therefore be a target for therapeutic intervention.
Comparative genomics identification of a novel set of temporally regulated hedgehog target genes in the retina.

Science.gov (United States)

McNeill, Brian; Perez-Iratxeta, Carol; Mazerolle, Chantal; Furimsky, Marosh; Mishina, Yuji; Andrade-Navarro, Miguel A; Wallace, Valerie A

2012-03-01

The hedgehog (Hh) signaling pathway is involved in numerous developmental and adult processes with many links to cancer. In vertebrates, the activity of the Hh pathway is mediated primarily through three Gli transcription factors (Gli1, 2 and 3) that can serve as transcriptional activators or repressors. The identification of Gli target genes is essential for the understanding of the Hh-mediated processes. We used a comparative genomics approach using the mouse and human genomes to identify 390 genes that contained conserved Gli binding sites. RT-qPCR validation of 46 target genes in E14.5 and P0.5 retinal explants revealed that Hh pathway activation resulted in the modulation of 30 of these targets, 25 of which demonstrated a temporal regulation. Further validation revealed that the expression of Bok, FoxA1, Sox8 and Wnt7a was dependent upon Sonic Hh (Shh) signaling in the retina and their regulation is under positive and negative controls by Gli2 and Gli3, respectively. We also show using chromatin immunoprecipitation that Gli2 binds to the Sox8 promoter, suggesting that Sox8 is an Hh-dependent direct target of Gli2. Finally, we demonstrate that the Hh pathway also modulates the expression of Sox9 and Sox10, which together with Sox8 make up the SoxE group. Previously, it has been shown that Hh and SoxE group genes promote Müller glial cell development in the retina. Our data are consistent with the possibility for a role of SoxE group genes downstream of Hh signaling on Müller cell development. Crown Copyright Â© 2012. Published by Elsevier Inc. All rights reserved.
An R2R3-MYB transcription factor, OjMYB1, functions in anthocyanin biosynthesis in Oenanthe javanica.

Science.gov (United States)

Feng, Kai; Xu, Zhi-Sheng; Que, Feng; Liu, Jie-Xia; Wang, Feng; Xiong, Ai-Sheng

2018-02-01

This study showed that an R2R3-MYB transcription factor, OjMYB1, is involved in anthocyanin biosynthesis and accumulation in Oenanthe javanica. Anthocyanins can be used as safe natural food colorants, obtained from many plants. R2R3-MYB transcription factors (TFs) play important roles in anthocyanins biosynthesis during plant development. Oenanthe javanica is a popular vegetable with high nutritional values and numerous medical functions. O. javanica has purple petioles that are mainly due to anthocyanins accumulation. In the present study, the gene encoding an R2R3-MYB TF, OjMYB1, was isolated from purple O. javanica. Sequencing results showed that OjMYB1 contained a 912-bp open reading frame encoding 303 amino acids. Sequence alignments revealed that OjMYB1 contained bHLH-interaction motif ([DE]Lx2[RK]x3Lx6Lx3R) and ANDV motif ([A/G]NDV). Phylogenetic analysis indicated that the OjMYB1 classified into the anthocyanins biosynthesis clade. Subcellular localization assay showed that OjMYB1 was a nuclear protein in vivo. The heterologous expression of OjMYB1 in Arabidopsis could enhance the anthocyanins content and up-regulate the expression levels of the structural genes-related anthocyanins biosynthesis. Yeast two-hybrid assay indicated that OjMYB1 could interact with AtTT8 and AtEGL3 proteins. Enzymatic analysis revealed that overexpression of OjMYB1 gene up-regulated the enzyme activity of 3-O-glycosyltransferase encoded by AtUGT78D2 in transgenic Arabidopsis. Our results provided a comprehensive understanding of the structure and function of OjMYB1 TF in O. javanica.
The DNA damage- and transcription-associated protein Paxip1 controls thymocyte development and emigration

DEFF Research Database (Denmark)

Callen, E.; Faryabi, R.B.; Daniel, Jeremy Austin

2012-01-01

Histone 3 lysine 4 trimethylation (H3K4me3) is associated with promoters of active genes and found at hot spots for DNA recombination. Here we have shown that PAXIP1 (also known as PTIP), a protein associated with MLL3 and MLL4 methyltransferase and the DNA damage response, regulates RAG......-mediated cleavage and repair during V(D)J recombination in CD4 CD8 DP thymocytes. Loss of PAXIP1 in developing thymocytes diminished Jα H3K4me3 and germline transcription, suppressed double strand break formation at 3' Jα segments, but resulted in accumulation of unresolved T cell receptor α-chain gene (Tcra......) breaks. Moreover, PAXIP1 was essential for release of mature single positive (SP) αβ T cells from the thymus through transcriptional activation of sphingosine-1-phosphate receptor S1pr1 as well as for natural killer T cell development. Thus, in addition to maintaining genome integrity during Tcra...
Identification of novel small molecules that inhibit STAT3-dependent transcription and function.

Directory of Open Access Journals (Sweden)

Iryna Kolosenko

Full Text Available Activation of Signal Transducer and Activator of Transcription 3 (STAT3 has been linked to several processes that are critical for oncogenic transformation, cancer progression, cancer cell proliferation, survival, drug resistance and metastasis. Inhibition of STAT3 signaling has shown a striking ability to inhibit cancer cell growth and therefore, STAT3 has become a promising target for anti-cancer drug development. The aim of this study was to identify novel inhibitors of STAT-dependent gene transcription. A cellular reporter-based system for monitoring STAT3 transcriptional activity was developed which was suitable for high-throughput screening (Z' = 0,8. This system was used to screen a library of 28,000 compounds (the ENAMINE Drug-Like Diversity Set. Following counter-screenings and toxicity studies, we identified four hit compounds that were subjected to detailed biological characterization. Of the four hits, KI16 stood out as the most promising compound, inhibiting STAT3 phosphorylation and transcriptional activity in response to IL6 stimulation. In silico docking studies showed that KI16 had favorable interactions with the STAT3 SH2 domain, however, no inhibitory activity could be observed in the STAT3 fluorescence polarization assay. KI16 inhibited cell viability preferentially in STAT3-dependent cell lines. Taken together, using a targeted, cell-based approach, novel inhibitors of STAT-driven transcriptional activity were discovered which are interesting leads to pursue further for the development of anti-cancer therapeutic agents.
Effect of mutations in HNF-1α and HNF-1β on the transcriptional regulation of human sucrase-isomaltase in Caco-2 cells

International Nuclear Information System (INIS)

Gu, Ning; Suzuki, Naoko; Takeda, Jun; Adachi, Tetsuya; Tsujimoto, Gozoh; Aoki, Norihiko; Ishihara, Akihiko; Tsuda, Kinsuke; Yasuda, Koichiro

2004-01-01

Mutations in transcription factors hepatocyte nuclear factors (HNF)-1α and HNF-1β cause maturity-onset diabetes of the young (MODY) types 3 and 5, respectively. HNF-1α and HNF-1β mutations are well studied in some tissues, but the mechanism by which HNF-1α and HNF-1β mutations affect sucrase-isomaltase (SI) transcription in the small intestine is unclear. We studied the effects of 13 HNF-1α mutants and 2 HNF-1β mutants on human SI gene transcription, which were identified in subjects with MODY3 and MODY5, respectively. Transactivation activity of 11 HNF-1α and 2 HNF-1β mutants was significantly lower than that of wild (wt)-HNF-1α and wt-HNF-1β. Furthermore, in co-expression studies with mutant (mu)-HNF-1α/ wt-HNF-1β and wt-HNF-1α/mu-HNF-1β, the combination of mu-HNF-1α (P379fsdelCT and T539fsdelC)/wt-HNF-1β impaired SI transcription, but the others were not remarkably different from wt-HNF-1α/wt-HNF-1β. Although wt-HNF-1β inhibited the transactivation activity of wt-HNF-1α on SI transcription, the inhibitory effect was reduced by 2 HNF-1β mutants. These results suggest that SI transcription might tend to be unchanged or lower in MODY3, while occurring more in MODY5
The Signal Transducer and Activator of Transcription 1 (STAT1 Inhibits Mitochondrial Biogenesis in Liver and Fatty Acid Oxidation in Adipocytes.

Directory of Open Access Journals (Sweden)

Jennifer D Sisler

Full Text Available The transcription factor STAT1 plays a central role in orchestrating responses to various pathogens by activating the transcription of nuclear-encoded genes that mediate the antiviral, the antigrowth, and immune surveillance effects of interferons and other cytokines. In addition to regulating gene expression, we report that STAT1-/- mice display increased energy expenditure and paradoxically decreased release of triglycerides from white adipose tissue (WAT. Liver mitochondria from STAT1-/- mice show both defects in coupling of the electron transport chain (ETC and increased numbers of mitochondria. Consistent with elevated numbers of mitochondria, STAT1-/- mice expressed increased amounts of PGC1α, a master regulator of mitochondrial biogenesis. STAT1 binds to the PGC1α promoter in fed mice but not in fasted animals, suggesting that STAT1 inhibited transcription of PGC1α. Since STAT1-/- mice utilized more lipids we examined white adipose tissue (WAT stores. Contrary to expectations, fasted STAT1-/- mice did not lose lipid from WAT. β-adrenergic stimulation of glycerol release from isolated STAT1-/- WAT was decreased, while activation of hormone sensitive lipase was not changed. These findings suggest that STAT1-/- adipose tissue does not release glycerol and that free fatty acids (FFA re-esterify back to triglycerides, thus maintaining fat mass in fasted STAT1-/- mice.
Overexpression of octamer transcription factors 1 or 2 alone has no effect on HIV-1 transcription in primary human CD4 T cells

International Nuclear Information System (INIS)

Zhang Mingce; Genin, Anna; Cron, Randy Q.

2004-01-01

We explored the binding of octamer (Oct) transcription factors to the HIV-1 long terminal repeat (LTR) by gel shift assays and showed none of the previously identified four potential Oct binding sites bound Oct-1 or Oct-2. Overexpression of Oct-1 or Oct-2 had no effect on HIV-1 LTR activity in transiently transfected primary human CD4 T cells. Next, primary human CD4 T cells were co-transfected with a green fluorescent protein (GFP)-expression vector and an Oct-1 or Oct-2 expression plasmid. The transfected cells were stimulated for 2 days and then infected with the NL4-3 strain of HIV-1. After 3 days of infection, there were no differences in HIV-1 p24 supernatant levels. Apoptosis of infected or bystander cells overexpressing Oct-1 or Oct-2 compared to control was also unaffected. Our studies demonstrate that Oct-1 and Oct-2 fail to bind to the HIV-1 LTR and have no effect on HIV-1 transcription in primary human CD4 T cells
Activated Rac1 requires gp130 for Stat3 activation, cell proliferation and migration

International Nuclear Information System (INIS)

Arulanandam, Rozanne; Geletu, Mulu; Feracci, Helene; Raptis, Leda

2010-01-01

Rac1 (Rac) is a member of the Rho family of small GTPases which controls cell migration by regulating the organization of actin filaments. Previous results suggested that mutationally activated forms of the Rho GTPases can activate the Signal Transducer and Activator of Transcription-3 (Stat3), but the exact mechanism is a matter of controversy. We recently demonstrated that Stat3 activity of cultured cells increases dramatically following E-cadherin engagement. To better understand this pathway, we now compared Stat3 activity levels in mouse HC11 cells before and after expression of the mutationally activated Rac1 (Rac V12 ), at different cell densities. The results revealed for the first time a dramatic increase in protein levels and activity of both the endogenous Rac and Rac V12 with cell density, which was due to inhibition of proteasomal degradation. In addition, Rac V12 -expressing cells had higher Stat3, tyrosine-705 phosphorylation and activity levels at all densities, indicating that Rac V12 is able to activate Stat3. Further examination of the mechanism of Stat3 activation showed that Rac V12 expression caused a surge in mRNA of Interleukin-6 (IL6) family cytokines, known potent Stat3 activators. Knockdown of gp130, the common subunit of this family reduced Stat3 activity, indicating that these cytokines may be responsible for the Stat3 activation by Rac V12 . The upregulation of IL6 family cytokines was required for cell migration and proliferation induced by Rac V12 , as shown by gp130 knockdown experiments, thus demonstrating that the gp130/Stat3 axis represents an essential effector of activated Rac for the regulation of key cellular functions.
Activated Rac1 requires gp130 for Stat3 activation, cell proliferation and migration

Energy Technology Data Exchange (ETDEWEB)

Arulanandam, Rozanne; Geletu, Mulu [Departments of Microbiology and Immunology and Pathology and Molecular Medicine, and Queen' s University Cancer Institute, Queen' s University, Botterell Hall, Rm. 713, Kingston, Ontario, Canada K7L 3N6 (Canada); Feracci, Helene [Universite Bordeaux 1, Centre de Recherche Paul Pascal, CNRS UPR 8641, 33600 Pessac (France); Raptis, Leda, E-mail: raptisl@queensu.ca [Departments of Microbiology and Immunology and Pathology and Molecular Medicine, and Queen' s University Cancer Institute, Queen' s University, Botterell Hall, Rm. 713, Kingston, Ontario, Canada K7L 3N6 (Canada)

2010-03-10

Rac1 (Rac) is a member of the Rho family of small GTPases which controls cell migration by regulating the organization of actin filaments. Previous results suggested that mutationally activated forms of the Rho GTPases can activate the Signal Transducer and Activator of Transcription-3 (Stat3), but the exact mechanism is a matter of controversy. We recently demonstrated that Stat3 activity of cultured cells increases dramatically following E-cadherin engagement. To better understand this pathway, we now compared Stat3 activity levels in mouse HC11 cells before and after expression of the mutationally activated Rac1 (Rac{sup V12}), at different cell densities. The results revealed for the first time a dramatic increase in protein levels and activity of both the endogenous Rac and Rac{sup V12} with cell density, which was due to inhibition of proteasomal degradation. In addition, Rac{sup V12}-expressing cells had higher Stat3, tyrosine-705 phosphorylation and activity levels at all densities, indicating that Rac{sup V12} is able to activate Stat3. Further examination of the mechanism of Stat3 activation showed that Rac{sup V12} expression caused a surge in mRNA of Interleukin-6 (IL6) family cytokines, known potent Stat3 activators. Knockdown of gp130, the common subunit of this family reduced Stat3 activity, indicating that these cytokines may be responsible for the Stat3 activation by Rac{sup V12}. The upregulation of IL6 family cytokines was required for cell migration and proliferation induced by Rac{sup V12}, as shown by gp130 knockdown experiments, thus demonstrating that the gp130/Stat3 axis represents an essential effector of activated Rac for the regulation of key cellular functions.
Inhibitory effects of curcumin and capsaicin on phorbol ester-induced activation of eukaryotic transcription factors, NF-kappaB and AP-1.

Science.gov (United States)

Surh, Y J; Han, S S; Keum, Y S; Seo, H J; Lee, S S

2000-01-01

Recently, considerable attention has been focused on identifying dietary and medicinal phytochemicals that can inhibit, retard or reverse the multi-stage carcinogenesis. Spices and herbs contain phenolic substances with potent antioxidative and chemopreventive properties. Curcumin, a yellow colouring agent from turmeric and capsaicin, a pungent principle of red pepper exhibit profound anticarcinogenic and antimutagenic activities. Two well-defined eukaryotic transcription factors, nuclear factor-kappa B (NF-kappaB) and activator protein 1 (AP-1) have been implicated in pathogenesis of many human diseases including cancer. These transcription factors are known to be activated by a wide array of external stimuli, such as tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), tumor necrosis factor, reactive oxygen species, bacterial lipopolysaccharide, and ultraviolet. In the present study, we found that topical application of TPA onto dorsal skin of female ICR mice resulted in marked activation of epidermal NF-kappaB and AP-1. Curcumin and capsaicin, when topically applied prior to TPA, significantly attenuated TPA-induced activation of each transcription factor in mouse skin. Likewise, both compounds inhibited NF-kappaB and AP-1 activation in cultured human promyelocytic leukemia (HL-60) cells stimulated with TPA. Based on these findings, it is likely that curcumin and capsaicin exert anti-tumor promotional effects through suppression of the tumor promoter-induced activation of transcription factors, NF-kappaB and AP-1.
Pressure dependence of backbone chemical shifts in the model peptides Ac-Gly-Gly-Xxx-Ala-NH2.

Science.gov (United States)

Erlach, Markus Beck; Koehler, Joerg; Crusca, Edson; Kremer, Werner; Munte, Claudia E; Kalbitzer, Hans Robert

2016-06-01

For a better understanding of nuclear magnetic resonance (NMR) detected pressure responses of folded as well as unstructured proteins the availability of data from well-defined model systems are indispensable. In this work we report the pressure dependence of chemical shifts of the backbone atoms (1)H(α), (13)C(α) and (13)C' in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH2 (Xxx one of the 20 canonical amino acids). Contrary to expectation the chemical shifts of these nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The polynomial pressure coefficients B 1 and B 2 are dependent on the type of amino acid studied. The coefficients of a given nucleus show significant linear correlations suggesting that the NMR observable pressure effects in the different amino acids have at least partly the same physical cause. In line with this observation the magnitude of the second order coefficients of nuclei being direct neighbors in the chemical structure are also weakly correlated.

Effects of chlorpyrifos on the transcription of CYP3A cDNA, activity of acetylcholinesterase, and oxidative stress response of goldfish (Carassius auratus).

Science.gov (United States)

Ma, Junguo; Liu, Yang; Niu, Daichun; Li, Xiaoyu

2015-04-01

Chlorpyrifos (CPF) is the widely used organophosphate pesticide in agriculture throughout the world. It has been found that CPF is relatively safe to human but highly toxic to fish. In this study, acute toxicity of CPF on goldfish was determined and then the transcription of goldfish cytochrome P450 (CYP) 3A was evaluated after 96 h of CPF exposure at concentrations of 15.3 [1/10 50% lethal concentration (LC50 )] or 51 μg L(-1) (1/3 LC50 ) of CPF. Meanwhile, the enzymatic activities of acetylcholinesterase (AChE), superoxide dismutase (SOD), and catalase (CAT), total antioxidant activity (T-AOC), and the contents of malondialdehyde (MDA) in the liver or brain of goldfish were also determined. The results of acute toxicity testing showed that the 96-h LC50 of CPF to the goldfish was 153 μg L(-1) . Moreover, a length sequence of 1243 bp CYP3A cDNA encoding for 413 amino acids from goldfish liver was cloned. Polymerase chain reaction results reveal that CPF exposure downregulates CYP 3A transcription in goldfish liver, suggesting that goldfish CYP 3A may be not involved in CPF bioactivation. Finally, the results of biochemical assays indicate that 96 h of CPF exposure remarkably inhibits AChE activity in fish liver or brain, alters hepatic antioxidant enzyme activities, decreases brain T-AOC, and causes lipid peroxidation in fish liver. These results suggest that oxidative stress might be involved in CPF toxicity on goldfish. Copyright © 2013 Wiley Periodicals, Inc.
Sp1 transcriptional activity is up-regulated by phosphatase 2A in dividing T lymphocytes.

Science.gov (United States)

Lacroix, Isabelle; Lipcey, Carol; Imbert, Jean; Kahn-Perlès, Brigitte

2002-03-15

We have followed Sp1 expression in primary human T lymphocytes induced, via CD2 plus CD28 costimulation, to sustained proliferation and subsequent return to quiescence. Binding of Sp1 to wheat germ agglutinin lectin was not modified following activation, indicating that the overall glycosylation of the protein was unchanged. Sp1 underwent, instead, a major dephosphorylation that correlated with cyclin A expression and, thus, with cell cycle progression. A similar change was observed in T cells that re-entered cell cycle following secondary interleukin-2 stimulation, as well as in serum-induced proliferating NIH/3T3 fibroblasts. Phosphatase 2A (PP2A) appears involved because 1) treatment of dividing cells with okadaic acid or cantharidin inhibited Sp1 dephosphorylation and 2) PP2A dephosphorylated Sp1 in vitro and strongly interacted with Sp1 in vivo. Sp1 dephosphorylation is likely to increase its transcriptional activity because PP2A overexpression potentiated Sp1 site-driven chloramphenicol acetyltransferase expression in dividing Kit225 T cells and okadaic acid reversed this effect. This increase might be mediated by a stronger affinity of dephosphorylated Sp1 for DNA, as illustrated by the reduced DNA occupancy by hyperphosphorylated Sp factors from cantharidin- or nocodazole-treated cells. Finally, Sp1 dephosphorylation appears to occur throughout cell cycle except for mitosis, a likely common feature to all cycling cells.
New zinc-glycine-iodide complexes as a product of equilibrium and non-equilibrium crystallization in the Gly – ZnI2 – H2O system

Czech Academy of Sciences Publication Activity Database

Tepavitcharova, S.; Havlíček, D.; Matulková, I.; Rabadjieva, D.; Gergulova, R.; Plocek, Jiří; Němec, I.; Císařová, I.

2016-01-01

Roč. 1120, SEP (2016), s. 42-49 ISSN 0022-2860 Institutional support: RVO:61388980 Keywords : [Zn(gly)I2], [Zn(gly)2I2] * [Zn3(H2O)4(μ-gly)2I6] * Crystal structure * Vibrational spectra * Thermal behaviour Subject RIV: CA - Inorganic Chemistry Impact factor: 1.753, year: 2016
Direct interaction of natural and synthetic catechins with signal transducer activator of transcription 1 affects both its phosphorylation and activity

KAUST Repository

Menegazzi, Marta

2013-12-10

Our previous studies showed that (-)-epigallocatechin-3-gallate (EGCG) inhibits signal transducer activator of transcription 1 (STAT1) activation. Since EGCG may be a promising lead compound for new anti-STAT1 drug design, 15 synthetic catechins, characterized by the (-)-gallocatechin-3-gallate stereochemistry, were studied in the human mammary MDA-MB-231 cell line to identify the minimal structural features that preserve the anti-STAT1 activity. We demonstrate that the presence of three hydroxyl groups of B ring and one hydroxyl group in D ring is essential to preserve their inhibitory action. Moreover, a possible molecular target of these compounds in the STAT1 pathway was investigated. Our results demonstrate a direct interaction between STAT1 protein and catechins displaying anti-STAT1 activity. In particular, surface plasmon resonance (SPR) analysis and molecular modeling indicate the presence of two putative binding sites (a and b) with different affinity. Based on docking data, site-directed mutagenesis was performed, and interaction of the most active catechins with STAT1 was studied with SPR to test whether Gln518 on site a and His568 on site b could be important for the catechin-STAT1 interaction. Data indicate that site b has higher affinity for catechins than site a as the highest affinity constant disappears in the H568ASTAT1 mutant. Furthermore, Janus kinase 2 (JAK2) kinase assay data suggest that the contemporary presence in vitro of STAT1 and catechins inhibits JAK2-elicited STAT1 phosphorylation. The very tight catechin-STAT1 interaction prevents STAT1 phosphorylation and represents a novel, specific and efficient molecular mechanism for the inhibition of STAT1 activation. © Copyright 2014 Federation of European Biochemical Societies. All rights reserved.
c-Abl phosphorylation of Yin Yang 1's conserved tyrosine 254 in the spacer region modulates its transcriptional activity.

Science.gov (United States)

Daraiseh, Susan I; Kassardjian, Ari; Alexander, Karen E; Rizkallah, Raed; Hurt, Myra M

2018-05-25

Yin Yang 1 (YY1) is a multifunctional transcription factor that can activate or repress transcription depending on the promotor and/or the co-factors recruited. YY1 is phosphorylated in various signaling pathways and is critical for different biological functions including embryogenesis, apoptosis, proliferation, cell-cycle regulation and tumorigenesis. Here we report that YY1 is a substrate for c-Abl kinase phosphorylation at conserved residue Y254 in the spacer region. Pharmacological inhibition of c-Abl kinase by imatinib, nilotinib and GZD824, knock-down of c-Abl using siRNA, and the use of c-Abl kinase-dead drastically reduces tyrosine phosphorylation of YY1. Both radioactive and non-radioactive in vitro kinase assays, as well as co-immunoprecipitation in different cell lines, show that the target of c-Abl phosphorylation is tyrosine residue 254. c-Abl phosphorylation has little effect on YY1 DNA binding ability or cellular localization in asynchronous cells. However, functional studies reveal that c-Abl mediated phosphorylation of YY1 regulates YY1's transcriptional ability in vivo. In conclusion, we demonstrate the novel role of c-Abl kinase in regulation of YY1's transcriptional activity, linking YY1 regulation with c-Abl tyrosine kinase signaling pathways. Copyright © 2018. Published by Elsevier B.V.
Penta-acetyl geniposide-induced apoptosis involving transcription of NGF/p75 via MAPK-mediated AP-1 activation in C6 glioma cells

International Nuclear Information System (INIS)

Peng, C.-H.; Huang, C.-N.; Hsu, S.-P.; Wang, C.-J.

2007-01-01

We have demonstrated the herbal derivative penta-acetyl geniposide ((Ac) 5 GP) induces C6 glioma cell apoptosis through the critical sphingomyelinase (SMase)/nerve growth factor (NGF)/p75 and its downstream signals. It has been reported mitogen-activated protein kinase (MAPK) mediates NGF synthesis induced by SMase activation. In this study, ERK, p38 and JNK are shown to mediate (Ac) 5 GP-induced glioma cell apoptosis and elevation of NGF and p75. Treatment of PD98059 (ERK-specific inhibitor), SB203580 (p38 MAPK inhibitor) and SP600125 (JNK inhibitor) decreases the elevation of NGF and p75 mRNA induced by (Ac) 5 GP, indicating possible transcription regulation via MAPKs. The results of nuclear extract blotting and EMSA further confirm (Ac) 5 GP maximally increases AP-1 and NF-κB DNA binding at 6 h. Inhibition of ERK, p38 and JNK block the activation of AP-1 and NF-κB, suggesting these MAPKs are involved in (Ac) 5 GP-induced transcription regulation. We thereby used RT-PCR to analyze cells treated with (Ac) 5 GP, with or without AP-1 or NF-κB inhibitors. AP-1 inhibitor NDGA decreases NGF/p75 and expression of FasL and caspase 3 induced by (Ac) 5 GP, suggesting the importance of AP-1 in mediating NGF/p75 and their downstream apoptotic signals. However, FasL and caspase 3 do not change with the NF-κB inhibitor PDTC; NF-κB might be linked to other cellular events. Overall, we demonstrate that MAPK mediates (Ac) 5 GP-induced activation of AP-1, promoting the transcription of NGF/p75 and downstream apoptotic signals. These results further highlight the potential therapeutic effects of (Ac) 5 GP in chemoprevention or as an anti-tumor agent
Glycogen Synthase Kinase-3 regulates IGFBP-1 gene transcription through the Thymine-rich Insulin Response Element

Directory of Open Access Journals (Sweden)

Marquez Rodolfo

2004-09-01

Full Text Available Abstract Background Hepatic expression of several gene products involved in glucose metabolism, including phosphoenolpyruvate carboxykinase (PEPCK, glucose-6-phosphatase (G6Pase and insulin-like growth factor binding protein-1 (IGFBP-1, is rapidly and completely inhibited by insulin. This inhibition is mediated through the regulation of a DNA element present in each of these gene promoters, that we call the Thymine-rich Insulin Response Element (TIRE. The insulin signalling pathway that results in the inhibition of these gene promoters requires the activation of phosphatidylinositol 3-kinase (PI 3-kinase. However, the molecules that connect PI 3-kinase to these gene promoters are not yet fully defined. Glycogen Synthase Kinase 3 (GSK-3 is inhibited following activation of PI 3-kinase. We have shown previously that inhibitors of GSK-3 reduce the activity of two TIRE-containing gene promoters (PEPCK and G6Pase, whose products are required for gluconeogenesis. Results In this report we demonstrate that in H4IIE-C3 cells, four distinct classes of GSK-3 inhibitor mimic the effect of insulin on a third TIRE-containing gene, IGFBP-1. We identify the TIRE as the minimum requirement for inhibition by these agents, and demonstrate that the target of GSK-3 is unlikely to be the postulated TIRE-binding protein FOXO-1. Importantly, overexpression of GSK-3 in cells reduces the insulin regulation of TIRE activity as well as endogenous IGFBP-1 expression. Conclusions These results implicate GSK-3 as an intermediate in the pathway from the insulin receptor to the TIRE. Indeed, this is the first demonstration of an absolute requirement for GSK-3 inhibition in insulin regulation of gene transcription. These data support the potential use of GSK-3 inhibitors in the treatment of insulin resistant states such as Type 2 diabetes mellitus, but suggest that it will be important to identify all TIRE-containing genes to assess potential side effects of these agents.
Cooperative activation of transcription by autoimmune regulator AIRE and CBP

International Nuclear Information System (INIS)

Pitkaenen, J.; Rebane, A.; Rowell, J.; Murumaegi, A.; Stroebel, P.; Moell, K.; Saare, M.; Heikkilae, J.; Doucas, V.; Marx, A.; Peterson, P.

2005-01-01

Autoimmune regulator (AIRE) is a transcriptional regulator that is believed to control the expression of tissue-specific genes in the thymus. Mutated AIRE is responsible for onset of the hereditary autoimmune disease APECED. AIRE is able to form nuclear bodies (NBs) and interacts with the ubiquitous transcriptional coactivator CBP. In this paper, we show that CBP and AIRE synergistically activate transcription on different promoter reporters whereas AIRE gene mutation R257X, found in APECED patients, interferes with this coactivation effect. Furthermore, the overexpression of AIRE and CBP collaboratively enhance endogenous IFNβ mRNA expression. The immunohistochemical studies suggest that CBP, depending on the balance of nuclear proteins, is a component of AIRE NBs. We also show that AIRE NBs are devoid of active chromatin and, therefore, not sites of transcription. In addition, we demonstrate by 3D analyses that AIRE and CBP, when colocalizing, are located spatially differently within AIRE NBs. In conclusion, our data suggest that AIRE activates transcription of the target genes, i.e., autoantigens in collaboration with CBP and that this activation occurs outside of AIRE NBs
Novel Functions for TAF7, a Regulator of TAF1-independent Transcription

OpenAIRE

Devaiah, Ballachanda N.; Lu, Hanxin; Gegonne, Anne; Sercan, Zeynep; Zhang, Hongen; Clifford, Robert J.; Lee, Maxwell P.; Singer, Dinah S.

2010-01-01

The transcription factor TFIID components TAF7 and TAF1 regulate eukaryotic transcription initiation. TAF7 regulates transcription initiation of TAF1-dependent genes by binding to the acetyltransferase (AT) domain of TAF1 and inhibiting the enzymatic activity that is essential for transcription. TAF7 is released from the TAF1-TFIID complex upon completion of preinitiation complex assembly, allowing transcription to initiate. However, not all transcription is TAF1-dependent, and the role of TA...
Influence of turn (or fold) and local charge in fragmentation of the peptide analogue molecule CH3CO-Gly-NH2 following single-photon VUV (118.22 nm) ionization.

Science.gov (United States)

Bhattacharya, Atanu; Bernstein, Elliot R

2011-10-06

The radical cationic reactivity of the peptide analogue molecule CH(3)CO-Gly-NH(2) is addressed both experimentally and theoretically. The radical cation intermediate of CH(3)CO-Gly-NH(2) is created by single-photon ionization of this molecule at 118.22 nm (~10.5 eV). The two most stable conformers (C(7) and C(5)) of this molecule exhibit different folds along the backbone: the C(7) conformer has a γ-turn structure, and the C(5) conformer has a β-strand structure. The experimental results show that the radical cation intermediate of CH(3)CO-Gly-NH(2) dissociates and generates a fragment-ion signal at 73 amu that is observed through TOFMS. Theoretical results show how the fragment-ion signal at 73 amu is generated by only one conformer of CH(3)CO-Gly-NH(2) (C(7)) and how local charge and specific hydrogen bonding in the molecule influence fragmentation of the radical cation intermediate of CH(3)CO-Gly-NH(2). The specific fold of the molecule controls fragmentation of this reactive radical cation intermediate. Whereas the radical cation of the C(7) conformer dissociates through a hydrogen-transfer mechanism followed by HNCO elimination, the radical cation of the C(5) conformer does not dissociate at all. CASSCF calculations show that positive charge in the radical cationic C(7) conformer is localized at the NH(2)CO moiety of the molecular ion. This site-specific localization of the positive charge enhances the acidity of the terminal NH(2) group, facilitating hydrogen transfer from the NH(2) to the COCH(3) end of the molecular ion. Positive charge in the C(5) conformer of the CH(3)CO-Gly-NH(2) radical cation is, however, localized at the COCH(3) end of the molecular ion, and this conformer does not have enough energy to surmount the energy barrier to dissociation on the ion potential energy surface. CASSCF results show that conformation-specific localization of charge in the CH(3)CO-Gly-NH(2) molecular ion occurs as a result of the different hydrogen
Loss of Pin1 Suppresses Hedgehog-Driven Medulloblastoma Tumorigenesis

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Tao Xu

2017-03-01

Full Text Available Medulloblastoma is the most common malignant brain tumor in children. Therapeutic approaches to medulloblastoma (combination of surgery, radiotherapy, and chemotherapy have led to significant improvements, but these are achieved at a high cost to quality of life. Alternative therapeutic approaches are needed. Genetic mutations leading to the activation of the Hedgehog pathway drive tumorigenesis in ~30% of medulloblastoma. In a yeast two-hybrid proteomic screen, we discovered a novel interaction between GLI1, a key transcription factor for the mediation of Hedgehog signals, and PIN1, a peptidylprolyl cis/trans isomerase that regulates the postphosphorylation fate of its targets. The GLI1/PIN1 interaction was validated by reciprocal pulldowns using epitope-tagged proteins in HEK293T cells as well as by co-immunoprecipiations of the endogenous proteins in a medulloblastoma cell line. Our results support a molecular model in which PIN1 promotes GLI1 protein abundance, thus contributing to the positive regulation of Hedgehog signals. Most importantly, in vivo functional analyses of Pin1 in the GFAP-tTA;TRE-SmoA1 mouse model of Hedgehog-driven medulloblastoma demonstrate that the loss of Pin1 impairs tumor development and dramatically increases survival. In summary, the discovery of the GLI1/PIN1 interaction uncovers PIN1 as a novel therapeutic target in Hedgehog-driven medulloblastoma tumorigenesis.
Application of evolutionary algorithm methods to polypeptide folding: comparison with experimental results for unsolvated Ac-(Ala-Gly-Gly)5-LysH+

DEFF Research Database (Denmark)

Damsbo, Martin; Kinnear, Brian S; Hartings, Matthew R

2004-01-01

We present an evolutionary method for finding the low-energy conformations of polypeptides. The application, called FOLDAWAY,is based on a generic framework and uses several evolutionary operators as well as local optimization to navigate the complex energy landscape of polypeptides. It maintains...... mobility measurements. It has a flat energy landscape where helical and globular conformations have similar energies. FOLDAWAY locates several large groups of structures not found in previous molecular dynamics simulations for this peptide, including compact globular conformations, which are probably...... two complementary representations of the structures and uses the CHARMM force field for evaluating the energies. The method is applied to unsolvated Met-enkephalin and Ac-(Ala-Gly-Gly)(5)-Lys(+)H(+). Unsolvated Ac-(Ala-Gly-Gly)(5)-Lys(+)H(+) has been the object of recent experimental studies using ion...
Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPβ expression and activation.

Science.gov (United States)

Chen, Ching-Chu; Chuang, Wei-Ting; Lin, Ai-Hsuan; Tsai, Chia-Wen; Huang, Chin-Shiu; Chen, Yun-Ting; Chen, Haw-Wen; Lii, Chong-Kuei

2016-09-15

Andrographolide, a diterpenoid, is the most abundant terpenoid in Andrographis paniculata, a popular Chinese herbal medicine. Andrographolide displays diverse biological activities including hypoglycemia, hypolipidemia, anti-inflammation, and anti-tumorigenesis. Recent evidence indicates that andrographolide displays anti-obesity property by inhibiting lipogenic gene expression, however, the underlying mechanisms remain to be elucidated. In this study, the effects of andrographolide on transcription factor cascade and mitotic clonal expansion in 3T3-L1 preadipocyte differentiation into adipocyte were determined. Andrographolide dose-dependently (0-15μM) inhibited CCAAT/enhancer-binding protein α (C/EBPα) and C/EBPβ mRNA and protein expression as well as peroxisome proliferator-activated receptor γ (PPARγ) protein level during the adipogenesis of 3T3-L1 cells. Concomitantly, fatty acid synthase and stearoyl-CoA desaturase expression and lipid accumulation were attenuated by andrographolide. Oil-red O staining further showed that the first 48h after the initiation of differentiation was critical for andrographolide inhibition of adipocyte formation. Andrographolide inhibited the phosphorylation of PKA and the activation of cAMP response element-binding protein (CREB) in response to a differentiation cocktail, which led to attenuated C/EBPβ expression. In addition, ERK and GSK3β-dependent C/EBPβ phosphorylation was attenuated by andrographolide. Moreover, andrographolide suppressed cyclin A, cyclin E, and CDK2 expression and impaired the progression of mitotic clonal expansion (MCE) by arresting the cell cycle at the Go/G1 phase. Taken together, these results indicate that andrographolide has a potent anti-obesity action by inhibiting PKA-CREB-mediated C/EBPβ expression as well as C/EBPβ transcriptional activity, which halts MCE progression and attenuates C/EBPα and PPARγ expression. Copyright © 2016 Elsevier Inc. All rights reserved.
Cooperative transcription activation by Nurr1 and Pitx3 induces embryonic stem cell maturation to the midbrain dopamine neuron phenotype

DEFF Research Database (Denmark)

Martinat, Cecile; Bacci, Jean-Jacques; Leete, Thomas

2006-01-01

's disease. We sought to identify genes that can potentiate maturation of ES cell cultures to the midbrain DA neuron phenotype. A number of transcription factors have been implicated in the development of midbrain DA neurons by expression analyses and loss-of-function knockout mouse studies, including Nurr1......Midbrain dopamine (DA) neurons play a central role in the regulation of voluntary movement, and their degeneration is associated with Parkinson's disease. Cell replacement therapies, and in particular embryonic stem (ES) cell-derived DA neurons, offer a potential therapeutic venue for Parkinson......, Pitx3, Lmx1b, Engrailed-1, and Engrailed-2. However, none of these factors appear sufficient alone to induce the mature midbrain DA neuron phenotype in ES cell cultures in vitro, suggesting a more complex regulatory network. Here we show that Nurr1 and Pitx3 cooperatively promote terminal maturation...
Transcriptional activation of NAD+-dependent protein deacetylase SIRT1 by nuclear receptor TLX.

Science.gov (United States)

Iwahara, Naotoshi; Hisahara, Shin; Hayashi, Takashi; Horio, Yoshiyuki

2009-09-04

An orphan nuclear receptor TLX is a transcriptional repressor that promotes the proliferation and self-renewal of neural precursor cells (NPCs). SIRT1, an NAD(+)-dependent protein deacetylase, is highly expressed in the NPCs and participates in neurogenesis. Here, we found that TLX colocalized with SIRT1 and knockdown of TLX by small interfering RNAs decreased SIRT1 levels in NPCs. TLX increased the SIRT1 expression by binding to the newly identified TLX-activating element in the SIRT1 gene promoter in HEK293 cells. Thus, TLX is an inducer of SIRT1 and may contribute to neurogenesis both as a transactivator and as a repressor.
Transcriptional activation of NAD+-dependent protein deacetylase SIRT1 by nuclear receptor TLX

International Nuclear Information System (INIS)

Iwahara, Naotoshi; Hisahara, Shin; Hayashi, Takashi; Horio, Yoshiyuki

2009-01-01

An orphan nuclear receptor TLX is a transcriptional repressor that promotes the proliferation and self-renewal of neural precursor cells (NPCs). SIRT1, an NAD + -dependent protein deacetylase, is highly expressed in the NPCs and participates in neurogenesis. Here, we found that TLX colocalized with SIRT1 and knockdown of TLX by small interfering RNAs decreased SIRT1 levels in NPCs. TLX increased the SIRT1 expression by binding to the newly identified TLX-activating element in the SIRT1 gene promoter in HEK293 cells. Thus, TLX is an inducer of SIRT1 and may contribute to neurogenesis both as a transactivator and as a repressor.
Variantes polimórficas Ala513Pro y Gly972Arg del gen IRS-1 no se asocian a la diabetes mellitus tipo 2 en un grupo de la población cubana The Ala513Pro and Gly972ARg polymorphous variants of IRS-1 gen are not associated with type diabetes mellitus in a group of the Cuban population

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Luis Miguel Pérez

2011-08-01

Full Text Available Introducción: la diabetes mellitus tipo 2 es una enfermedad heterogénea y multifactorial, que está determinada por factores genéticos y no genéticos. El sustrato 1 del receptor de la insulina (IRS-1 cumple una función fundamental en la transmisión de la señal insulínica, por tanto sus variantes génicas constituyen blancos importantes en el estudio de la susceptibilidad genética a esta enfermedad en las diferentes poblaciones. Objetivo: explorar el papel de las variantes polimórficas Gly972Arg y Ala513Pro del gen IRS-1 en la susceptibilidad genética de la diabetes mellitus tipo 2 en un grupo de la población cubana. Métodos: se determinó la frecuencia de los polimorfismos Gly972Arg y Ala513Pro del IRS-1 en 499 ciudadanos cubanos, con un índice de masa corporal entre 22-30, con edades comprendidas entre los 40 y 70 años: de ellos 272 (54,5 % diabéticos y 227 (45,5 % no diabéticos. Resultados: la frecuencia del alelo Pro513 fue baja (1,2 % y similar para ambos grupos (1,1 % vs. 1,3 % para el grupo de diabéticos y el grupo control, respectivamente. La frecuencia del polimorfismo Gly972Arg fue de 16,2%, superior a la reportada para la mayoría de las poblaciones estudiadas. No se encontraron diferencias significativas en la frecuencia del alelo Arg972 entre el grupo de diabéticos y el grupo control (15,4 % vs. 17,3 %, ni cambios en los niveles de glucemia e insulinemia asociados a la presencia del alelo polimórfico Arg972. Conclusiones: en este grupo de sujetos de la población cubana, las variantes polimórficas Ala513Pro y Gly972Arg del gen IRS-1 no participan en la etiología de la diabetes mellitus tipo 2.Introduction: the type 2 diabetes mellitus is a heterogeneous and multifactor disease determined by genetic and no-genetic factors. The substrate 1 of insulin receptor (IRS-1 has a fundamental function in transmission of insulin signal, thus its genic variants are significant targets in study of genetic susceptibility to
Pressure dependence of backbone chemical shifts in the model peptides Ac-Gly-Gly-Xxx-Ala-NH{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Erlach, Markus Beck; Koehler, Joerg [University of Regensburg, Institute of Biophysics and Physical Biochemistry and Centre of Magnetic Resonance in Chemistry and Biomedicine (Germany); Crusca, Edson [University of São Paulo, Physics Institute of São Carlos (Brazil); Kremer, Werner [University of Regensburg, Institute of Biophysics and Physical Biochemistry and Centre of Magnetic Resonance in Chemistry and Biomedicine (Germany); Munte, Claudia E. [University of São Paulo, Physics Institute of São Carlos (Brazil); Kalbitzer, Hans Robert, E-mail: hans-robert.kalbitzer@biologie.uni-regensburg.de [University of Regensburg, Institute of Biophysics and Physical Biochemistry and Centre of Magnetic Resonance in Chemistry and Biomedicine (Germany)

2016-06-15

For a better understanding of nuclear magnetic resonance (NMR) detected pressure responses of folded as well as unstructured proteins the availability of data from well-defined model systems are indispensable. In this work we report the pressure dependence of chemical shifts of the backbone atoms {sup 1}H{sup α}, {sup 13}C{sup α} and {sup 13}C′ in the protected tetrapeptides Ac-Gly-Gly-Xxx-Ala-NH{sub 2} (Xxx one of the 20 canonical amino acids). Contrary to expectation the chemical shifts of these nuclei have a nonlinear dependence on pressure in the range from 0.1 to 200 MPa. The polynomial pressure coefficients B{sub 1} and B{sub 2} are dependent on the type of amino acid studied. The coefficients of a given nucleus show significant linear correlations suggesting that the NMR observable pressure effects in the different amino acids have at least partly the same physical cause. In line with this observation the magnitude of the second order coefficients of nuclei being direct neighbors in the chemical structure are also weakly correlated.Graphical Abstract.
Association of CD30 transcripts with Th1 responses and proinflammatory cytokines in patients with end-stage renal disease.

Science.gov (United States)

Velásquez, Sonia Y; Opelz, Gerhard; Rojas, Mauricio; Süsal, Caner; Alvarez, Cristiam M

2016-05-01

High serum sCD30 levels are associated with inflammatory disorders and poor outcome in renal transplantation. The contribution to these phenomena of transcripts and proteins related to CD30-activation and -cleavage is unknown. We assessed in peripheral blood of end-stage renal disease patients (ESRDP) transcripts of CD30-activation proteins CD30 and CD30L, CD30-cleavage proteins ADAM10 and ADAM17, and Th1- and Th2-type immunity-related factors t-bet and GATA3. Additionally, we evaluated the same transcripts and release of sCD30 and 32 cytokines after allogeneic and polyclonal T-cell activation. In peripheral blood, ESRDP showed increased levels of t-bet and GATA3 transcripts compared to healthy controls (HC) (both PCD30, CD30L, ADAM10 and ADAM17 transcripts were similar. Polyclonal and allogeneic stimulation induced higher levels of CD30 transcripts in ESRDP than in HC (both PsCD30, the Th-1 cytokine IFN-γ, MIP-1α, RANTES, sIL-2Rα, MIP-1β, TNF-β, MDC, GM-CSF and IL-5, and another one consisting of CD30 and t-bet transcripts, IL-13 and proinflammatory proteins IP-10, IL-8, IL-1Rα and MCP-1. Reflecting an activated immune state, ESRDP exhibited after allostimulation upregulation of CD30 transcripts in T cells, which was associated with Th1 and proinflammatory responses. Copyright © 2016 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.
Hes1 promotes the IL-22-mediated antimicrobial response by enhancing STAT3-dependent transcription in human intestinal epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Murano, Tatsuro [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Okamoto, Ryuichi, E-mail: rokamoto.gast@tmd.ac.jp [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Department of Advanced GI Therapeutics, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Ito, Go; Nakata, Toru; Hibiya, Shuji; Shimizu, Hiromichi; Fujii, Satoru; Kano, Yoshihito; Mizutani, Tomohiro; Yui, Shiro; Akiyama-Morio, Junko; Nemoto, Yasuhiro [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Tsuchiya, Kiichiro; Nakamura, Tetsuya [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Department of Advanced GI Therapeutics, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Watanabe, Mamoru [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan)

2014-01-17

Highlights: •Hes1 enhances IL-22-STAT3 signaling in human intestinal epithelial cells. •Hes1 enhances REG family gene induction by IL-22-STAT3 signaling. •Protein level of Hes1 restricts the response to IL-22. •Present regulation of a cytokine signal represents a new mode of Hes1 function. -- Abstract: Notch signaling plays an essential role in the proliferation and differentiation of intestinal epithelial cells (IECs). We have previously shown that Notch signaling is up-regulated in the inflamed mucosa of ulcerative colitis (UC) and thereby plays an indispensable role in tissue regeneration. Here we show that in addition to Notch signaling, STAT3 signaling is highly activated in the inflamed mucosa of UC. Forced expression of the Notch target gene Hes1 dramatically enhanced the IL-22-mediated STAT3-dependent transcription in human IECs. This enhancement of STAT3-dependent transcription was achieved by the extended phosphorylation of STAT3 by Hes1. Microarray analysis revealed that Hes1-mediated enhancement of IL-22-STAT3 signaling significantly increased the induction of genes encoding antimicrobial peptides, such as REG1A, REG3A and REG3G, in human IECs. Conversely, the reduction of Hes1 protein levels with a γ-secretase inhibitor significantly down-regulated the induction of those genes in IECs, resulting in a markedly poor response to IL-22. Our present findings identify a new role for the molecular function of Hes1 in which the protein can interact with cytokine signals and regulate the immune response of IECs.

Scaling proprioceptor gene transcription by retrograde NT3 signaling.

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Jun Lee

Full Text Available Cell-type specific intrinsic programs instruct neuronal subpopulations before target-derived factors influence later neuronal maturation. Retrograde neurotrophin signaling controls neuronal survival and maturation of dorsal root ganglion (DRG sensory neurons, but how these potent signaling pathways intersect with transcriptional programs established at earlier developmental stages remains poorly understood. Here we determine the consequences of genetic alternation of NT3 signaling on genome-wide transcription programs in proprioceptors, an important sensory neuron subpopulation involved in motor reflex behavior. We find that the expression of many proprioceptor-enriched genes is dramatically altered by genetic NT3 elimination, independent of survival-related activities. Combinatorial analysis of gene expression profiles with proprioceptors isolated from mice expressing surplus muscular NT3 identifies an anticorrelated gene set with transcriptional levels scaled in opposite directions. Voluntary running experiments in adult mice further demonstrate the maintenance of transcriptional adjustability of genes expressed by DRG neurons, pointing to life-long gene expression plasticity in sensory neurons.
Transcriptional effects of 1,25 dihydroxyvitamin D{sub 3} physiological and supra-physiological concentrations in breast cancer organotypic culture

Energy Technology Data Exchange (ETDEWEB)

Milani, Cintia [Disciplina de Oncologia, LIM24, Departamento de Radiologia e Oncologia, Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo 455,Sala 4124, São Paulo, SP, 01246-903 (Brazil); Góes, João Carlos Guedes Sampaio [Instituto Brasileiro de Controle do Câncer, IBCC, São Paulo (Brazil); Nonogaki, Suely [Instituto Adolfo Lutz, Centro de Patologia, Núcleo de Patologia Quantitativa, São Paulo (Brazil); Tamura, Rodrigo Esaki [Post-doctoral fellow, Viral Vectors Laboratory, Instituto do Câncer do Estado de São Paulo, ICESP, São Paulo (Brazil); Folgueira, Maria Aparecida Azevedo Koike; Katayama, Maria Lucia Hirata [Disciplina de Oncologia, LIM24, Departamento de Radiologia e Oncologia, Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo 455,Sala 4124, São Paulo, SP, 01246-903 (Brazil); Lyra, Eduardo Carneiro de [Disciplina de Oncologia, LIM24, Departamento de Radiologia e Oncologia, Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo 455,Sala 4124, São Paulo, SP, 01246-903 (Brazil); Instituto Brasileiro de Controle do Câncer, IBCC, São Paulo (Brazil); Welsh, JoEllen [Department of Environmental Health Sciences, School of Public Health, University at Albany, Rensselaer, NY, 12144 (United States); Campos, Laura Tojeiro; Brentani, M Mitzi [Disciplina de Oncologia, LIM24, Departamento de Radiologia e Oncologia, Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo 455,Sala 4124, São Paulo, SP, 01246-903 (Brazil); Maciel, Maria do Socorro [Hospital do Câncer A. C. Camargo, São Paulo (Brazil); Roela, Rosimeire Aparecida; Valle, Paulo Roberto del [Disciplina de Oncologia, LIM24, Departamento de Radiologia e Oncologia, Faculdade de Medicina da Universidade de São Paulo, Av. Dr. Arnaldo 455,Sala 4124, São Paulo, SP, 01246-903 (Brazil)

2013-03-15

trend towards up-regulation of CA2, IL1RL1, and DPP4. A higher protein expression of CD14 in epithelial cells and CA2 and DPP4 in CAFs exposed to 1,25(OH){sub 2}D{sub 3} 0.5nM was detected. In breast cancer specimens a short period of 1,25(OH){sub 2}D{sub 3} exposure at near physiological concentration modestly activates the hormone transcriptional pathway. Induction of CYP24A1, CA2, DPP4, IL1RL1 expression appears to reflect 1,25(OH){sub 2}D{sub 3} effects in epithelial as well as stromal cells, however, induction of CD14 expression is likely restricted to the epithelial compartment.
PEA3 activates CXCR4 transcription in MDA-MB-231 and MCF7 breast cancer cells

Institute of Scientific and Technical Information of China (English)

Shengmei Gu; Li Chen; Qi Hong; Tingting Yan; Zhigang Zhuang; Qiaoqiao wang; Wei Jin; Hua Zhu; Jiong Wu

2011-01-01

CXC chemokine receptor 4 (CXCR4) is a cell surface receptor that has been shown to mediate the metastasis of many solid tumors including lung,breast,kidney,and prostate tumors.In this study,we found that overexpression of ets variant gene 4 (PEA3) could elevate CXCR4 mRNA level and CXCR4 promoter activity in human MDA-MB-231 and MCF-7 breast cancer cells.PEA3 promoted CXCR4 expression and breast cancer metastasis.Chromatin immunoprecipitation assay demonstrated that PEA3 could bind to the CXCR4 promoter in the cells transfected with PEA3 expression vector.PEA3 siRNA attenuated CXCR4 promoter activity and the binding of PEA3 to the CXCR4 promoter in MDA-MB-231 and MCF-7 cells.These results indicated that PEA3 could activate CXCR4 promoter transcription and promote breast cancer metastasis.
Activating transcription factor 3 promotes loss of the acinar cell phenotype in response to cerulein-induced pancreatitis in mice.

Science.gov (United States)

Fazio, Elena N; Young, Claire C; Toma, Jelena; Levy, Michael; Berger, Kurt R; Johnson, Charis L; Mehmood, Rashid; Swan, Patrick; Chu, Alphonse; Cregan, Sean P; Dilworth, F Jeffrey; Howlett, Christopher J; Pin, Christopher L

2017-09-01

Pancreatitis is a debilitating disease of the exocrine pancreas that, under chronic conditions, is a major susceptibility factor for pancreatic ductal adenocarcinoma (PDAC). Although down-regulation of genes that promote the mature acinar cell fate is required to reduce injury associated with pancreatitis, the factors that promote this repression are unknown. Activating transcription factor 3 (ATF3) is a key mediator of the unfolded protein response, a pathway rapidly activated during pancreatic insult. Using chromatin immunoprecipitation followed by next-generation sequencing, we show that ATF3 is bound to the transcriptional regulatory regions of >30% of differentially expressed genes during the initiation of pancreatitis. Of importance, ATF3-dependent regulation of these genes was observed only upon induction of pancreatitis, with pathways involved in inflammation, acinar cell differentiation, and cell junctions being specifically targeted. Characterizing expression of transcription factors that affect acinar cell differentiation suggested that acinar cells lacking ATF3 maintain a mature cell phenotype during pancreatitis, a finding supported by maintenance of junctional proteins and polarity markers. As a result, Atf3 -/- pancreatic tissue displayed increased tissue damage and inflammatory cell infiltration at early time points during injury but, at later time points, showed reduced acinar-to-duct cell metaplasia. Thus our results reveal a critical role for ATF3 as a key regulator of the acinar cell transcriptional response during injury and may provide a link between chronic pancreatitis and PDAC. © 2017 Fazio et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
Analysis of the Gli-D2 locus identifies a genetic target for simultaneously improving the breadmaking and health-related traits of common wheat.

Science.gov (United States)

Li, Da; Jin, Huaibing; Zhang, Kunpu; Wang, Zhaojun; Wang, Faming; Zhao, Yue; Huo, Naxin; Liu, Xin; Gu, Yong Q; Wang, Daowen; Dong, Lingli

2018-05-11

Gliadins are a major component of wheat seed proteins. However, the complex homoeologous Gli-2 loci (Gli-A2, -B2 and -D2) that encode the α-gliadins in commercial wheat are still poorly understood. Here we analyzed the Gli-D2 locus of Xiaoyan 81 (Xy81), a winter wheat cultivar. A total of 421.091 kb of the Gli-D2 sequence was assembled from sequencing multiple bacterial artificial clones, and 10 α-gliadin genes were annotated. Comparative genomic analysis showed that Xy81 carried only eight of the α-gliadin genes of the D genome donor Aegilops tauschii, with two of them each experiencing a tandem duplication. A mutant line lacking Gli-D2 (DLGliD2) consistently exhibited better breadmaking quality and dough functionalities than its progenitor Xy81, but without penalties in other agronomic traits. It also had an elevated lysine content in the grains. Transcriptome analysis verified the lack of Gli-D2 α-gliadin gene expression in DLGliD2. Furthermore, the transcript and protein levels of protein disulfide isomerase were both upregulated in DLGliD2 grains. Consistent with this finding, DLGliD2 had increased disulfide content in the flour. Our work sheds light on the structure and function of Gli-D2 in commercial wheat, and suggests that the removal of Gli-D2 and the gliadins specified by it is likely to be useful for simultaneously enhancing the end-use and health-related traits of common wheat. Because gliadins and homologous proteins are widely present in grass species, the strategy and information reported here may be broadly useful for improving the quality traits of diverse cereal crops. © 2018 The Authors The Plant Journal © 2018 John Wiley & Sons Ltd.
Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G1

DEFF Research Database (Denmark)

Kjaerulff, Søren; Andersen, Nicoline Resen; Borup, Mia Trolle

2007-01-01

Eukaryotic cells normally differentiate from G(1); here we investigate the mechanism preventing expression of differentiation-specific genes outside G(1). In fission yeast, induction of the transcription factor Ste11 triggers sexual differentiation. We find that Ste11 is only active in G(1) when...... Cdk activity is low. In the remaining part of the cell cycle, Ste11 becomes Cdk-phosphorylated at Thr 82 (T82), which inhibits its DNA-binding activity. Since the ste11 gene is autoregulated and the Ste11 protein is highly unstable, this Cdk switch rapidly extinguishes Ste11 activity when cells enter...... S phase. When we mutated T82 to aspartic acid, mimicking constant phosphorylation, cells no longer underwent differentiation. Conversely, changing T82 to alanine rendered Ste11-controlled transcription constitutive through the cell cycle, and allowed mating from S phase with increased frequency...
Elongation Factor Tu Prevents Misediting of Gly-tRNA(Gly Caused by the Design Behind the Chiral Proofreading Site of D-Aminoacyl-tRNA Deacylase.

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Satya Brata Routh

2016-05-01

Full Text Available D-aminoacyl-tRNA deacylase (DTD removes D-amino acids mischarged on tRNAs and is thus implicated in enforcing homochirality in proteins. Previously, we proposed that selective capture of D-aminoacyl-tRNA by DTD's invariant, cross-subunit Gly-cisPro motif forms the mechanistic basis for its enantioselectivity. We now show, using nuclear magnetic resonance (NMR spectroscopy-based binding studies followed by biochemical assays with both bacterial and eukaryotic systems, that DTD effectively misedits Gly-tRNAGly. High-resolution crystal structure reveals that the architecture of DTD's chiral proofreading site is completely porous to achiral glycine. Hence, L-chiral rejection is the only design principle on which DTD functions, unlike other chiral-specific enzymes such as D-amino acid oxidases, which are specific for D-enantiomers. Competition assays with elongation factor thermo unstable (EF-Tu and DTD demonstrate that EF-Tu precludes Gly-tRNAGly misediting at normal cellular concentrations. However, even slightly higher DTD levels overcome this protection conferred by EF-Tu, thus resulting in significant depletion of Gly-tRNAGly. Our in vitro observations are substantiated by cell-based studies in Escherichia coli that show that overexpression of DTD causes cellular toxicity, which is largely rescued upon glycine supplementation. Furthermore, we provide direct evidence that DTD is an RNA-based catalyst, since it uses only the terminal 2'-OH of tRNA for catalysis without the involvement of protein side chains. The study therefore provides a unique paradigm of enzyme action for substrate selection/specificity by DTD, and thus explains the underlying cause of DTD's activity on Gly-tRNAGly. It also gives a molecular and functional basis for the necessity and the observed tight regulation of DTD levels, thereby preventing cellular toxicity due to misediting.
Inhibition of Hedgehog signaling antagonizes serous ovarian cancer growth in a primary xenograft model.

Directory of Open Access Journals (Sweden)

Christopher K McCann

Full Text Available Recent evidence links aberrant activation of Hedgehog (Hh signaling with the pathogenesis of several cancers including medulloblastoma, basal cell, small cell lung, pancreatic, prostate and ovarian. This investigation was designed to determine if inhibition of this pathway could inhibit serous ovarian cancer growth.We utilized an in vivo pre-clinical model of serous ovarian cancer to characterize the anti-tumor activity of Hh pathway inhibitors cyclopamine and a clinically applicable derivative, IPI-926. Primary human serous ovarian tumor tissue was used to generate tumor xenografts in mice that were subsequently treated with cyclopamine or IPI-926.Both compounds demonstrated significant anti-tumor activity as single agents. When IPI-926 was used in combination with paclitaxel and carboplatinum (T/C, no synergistic effect was observed, though sustained treatment with IPI-926 after cessation of T/C continued to suppress tumor growth. Hh pathway activity was analyzed by RT-PCR to assess changes in Gli1 transcript levels. A single dose of IPI-926 inhibited mouse stromal Gli1 transcript levels at 24 hours with unchanged human intra-tumor Gli1 levels. Chronic IPI-926 therapy for 21 days, however, inhibited Hh signaling in both mouse stromal and human tumor cells. Expression data from the micro-dissected stroma in human serous ovarian tumors confirmed the presence of Gli1 transcript and a significant association between elevated Gli1 transcript levels and worsened survival.IPI-926 treatment inhibits serous tumor growth suggesting the Hh signaling pathway contributes to the pathogenesis of ovarian cancer and may hold promise as a novel therapeutic target, especially in the maintenance setting.
Transcriptional upregulation of BAG3 upon proteasome inhibition

International Nuclear Information System (INIS)

Wang Huaqin; Liu Haimei; Zhang Haiyan; Guan Yifu; Du Zhenxian

2008-01-01

Proteasome inhibitors exhibit antitumoral activity against malignancies of different histology. Emerging evidence indicates that antiapoptotic factors may also accumulate as a consequence of exposure to these drugs, thus it seems plausible that activation of survival signaling cascades might compromise their antitumoral effects. Bcl-2-associated athanogene (BAG) family proteins are characterized by their property of interaction with a variety of partners involved in modulating the proliferation/death balance, including heat shock proteins (HSP), Bcl-2, Raf-1. In this report, we demonstrated that BAG3 is a novel antiapoptotic molecule induced by proteasome inhibitors in various cancer cells at the transcriptional level. Moreover, we demonstrated that BAG3 knockdown by siRNA sensitized cancer cells to MG132-induced apoptosis. Taken together, our results suggest that BAG3 induction might represents as an unwanted molecular consequence of utilizing proteasome inhibitors to combat tumors
AKT phosphorylates H3-threonine 45 to facilitate termination of gene transcription in response to DNA damage.

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Lee, Jong-Hyuk; Kang, Byung-Hee; Jang, Hyonchol; Kim, Tae Wan; Choi, Jinmi; Kwak, Sojung; Han, Jungwon; Cho, Eun-Jung; Youn, Hong-Duk

2015-05-19

Post-translational modifications of core histones affect various cellular processes, primarily through transcription. However, their relationship with the termination of transcription has remained largely unknown. In this study, we show that DNA damage-activated AKT phosphorylates threonine 45 of core histone H3 (H3-T45). By genome-wide chromatin immunoprecipitation sequencing (ChIP-seq) analysis, H3-T45 phosphorylation was distributed throughout DNA damage-responsive gene loci, particularly immediately after the transcription termination site. H3-T45 phosphorylation pattern showed close-resemblance to that of RNA polymerase II C-terminal domain (CTD) serine 2 phosphorylation, which establishes the transcription termination signal. AKT1 was more effective than AKT2 in phosphorylating H3-T45. Blocking H3-T45 phosphorylation by inhibiting AKT or through amino acid substitution limited RNA decay downstream of mRNA cleavage sites and decreased RNA polymerase II release from chromatin. Our findings suggest that AKT-mediated phosphorylation of H3-T45 regulates the processing of the 3' end of DNA damage-activated genes to facilitate transcriptional termination. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
Primate-specific microRNA-637 inhibits tumorigenesis in hepatocellular carcinoma by disrupting signal transducer and activator of transcription 3 signaling.

Science.gov (United States)

Zhang, Jin-fang; He, Ming-liang; Fu, Wei-ming; Wang, Hua; Chen, Lian-zhou; Zhu, Xiao; Chen, Ying; Xie, Dan; Lai, Paul; Chen, Gong; Lu, Gang; Lin, Marie C M; Kung, Hsiang-fu

2011-12-01

MiR-637 (microRNA-637) is a primate-specific miRNA belonging to the small noncoding RNA family, which represses gene regulation at the post-transcriptional expression level. Although it was discovered approximately 5 years ago, its biomedical significance and regulatory mechanism remain obscure. Our preliminary data showed that miR-637 was significantly suppressed in four HCC cell lines and, also, in most of the hepatocellular carcinoma (HCC) specimens, thereby suggesting that miR-637 would be a tumor suppressor in HCC. Simultaneously, the enforced overexpression of miR-637 dramatically inhibited cell growth and induced the apoptosis of HCC cells. The transcription factor, signal transducer and activator of transcription 3 (Stat3), is constitutively activated in multiple tumors, and aberrant Stat3 activation is linked to the promotion of growth and desensitization of apoptosis. Our study showed that Stat3 tyrosine 705 phosphorylation and several Stat3-regulated antiapoptotic genes were down-regulated in miR-637 mimics-transfected and Lv-miR637-infected HCC cells. In addition, miR-637 overexpression negatively regulated Stat3 phosphorylation by suppressing autocrine leukemia inhibitory factor (LIF) expression and exogenous LIF-triggered Stat3 activation and rescued cell growth in these cells. A nude mice model also demonstrated the above-described results, which were obtained from the cell model. Furthermore, we found that LIF was highly expressed in a large proportion of HCC specimens, and its expression was inversely associated with miR-637 expression. Our data indicate that miR-637 acted as a tumor suppressor in HCC, and the suppressive effect was mediated, at least in part, by the disruption of Stat3 activation. Copyright © 2011 American Association for the Study of Liver Diseases.
Co-activation of STAT3 and YES-Associated Protein 1 (YAP1) Pathway in EGFR-Mutant NSCLC

DEFF Research Database (Denmark)

Chaib, Imane; Karachaliou, Niki; Pilotto, Sara

2017-01-01

Background: The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) in EGFR-mutant non-small cell lung cancer (NSCLC) is limited by adaptive activation of cell survival signals. We hypothesized that both signal transducer and activator of transcription 3 (STAT3) ...
Palmitoylation regulates 17β-estradiol-induced estrogen receptor-α degradation and transcriptional activity.

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La Rosa, Piergiorgio; Pesiri, Valeria; Leclercq, Guy; Marino, Maria; Acconcia, Filippo

2012-05-01

The estrogen receptor-α (ERα) is a transcription factor that regulates gene expression through the binding to its cognate hormone 17β-estradiol (E2). ERα transcriptional activity is regulated by E2-evoked 26S proteasome-mediated ERα degradation and ERα serine (S) residue 118 phosphorylation. Furthermore, ERα mediates fast cell responses to E2 through the activation of signaling cascades such as the MAPK/ERK and phosphoinositide-3-kinase/v-akt murine thymoma viral oncogene homolog 1 pathways. These E2 rapid effects require a population of the ERα located at the cell plasma membrane through palmitoylation, a dynamic enzymatic modification mediated by palmitoyl-acyl-transferases. However, whether membrane-initiated and transcriptional ERα activities integrate in a unique picture or represent parallel pathways still remains to be firmly clarified. Hence, we evaluated here the impact of ERα palmitoylation on E2-induced ERα degradation and S118 phosphorylation. The lack of palmitoylation renders ERα more susceptible to E2-dependent degradation, blocks ERα S118 phosphorylation and prevents E2-induced ERα estrogen-responsive element-containing promoter occupancy. Consequently, ERα transcriptional activity is prevented and the receptor addressed to the nuclear matrix subnuclear compartment. These data uncover a circuitry in which receptor palmitoylation links E2-dependent ERα degradation, S118 phosphorylation, and transcriptional activity in a unique molecular mechanism. We propose that rapid E2-dependent signaling could be considered as a prerequisite for ERα transcriptional activity and suggest an integrated model of ERα intracellular signaling where E2-dependent early extranuclear effects control late receptor-dependent nuclear actions.
Nodal enhances the activity of FoxO3a and its synergistic interaction with Smads to regulate cyclin G2 transcription in ovarian cancer cells.

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Fu, G; Peng, C

2011-09-15

Nodal, a member of the transforming growth factor-β superfamily, has been recently shown to suppress cell proliferation and to stimulate the expression of cyclin G2 (CCNG2) in human epithelial ovarian cancer cells. However, the precise mechanisms underlying these events are not fully understood. In this study, we investigated the transcriptional regulation of CCNG2 by the Nodal signaling pathway. In ovarian cancer cells, overexpression of Nodal or its receptors, activin receptor-like kinase 7 (ALK7) or ALK4, resulted in an increase in the CCNG2 promoter activity. Several putative Forkhead box class O (FoxO)3a-binding sites are present in the human CCNG2 promoter and overexpression of FoxO3a enhanced the CCNG2 promoter activity. The functional FoxO3a-binding element (FBE) was mapped to a proximal region located between -398 and -380 bp (FBE1) through deletion and mutation analyses, as well as chromatin immunoprecipitation (IP) assay. Interestingly, mutation of the FBE1 not only abolished the effect of FoxO3a, but also blocked Nodal-induced CCNG2 transcription. Nodal stimulated FoxO3a mRNA and protein expression through the canonical Smad pathway and suppressed FoxO3a inactivation by inhibiting AKT activity. Silencing of FoxO3a using small interfering RNA significantly reduced the effect of Nodal on the CCNG2 promoter activity. On the other hand, overexpression of Smad2 and Smad3 enhanced the FoxO3a-induced CCNG2 promoter activity whereas knockdown of Smad4 blocked the activity of FoxO3a. Furthermore, IP assays revealed that FoxO3a formed complexes with Smad proteins and that Nodal enhanced the binding of FoxO3a to the CCNG2 promoter. Finally, silencing of FoxO3a reversed the inhibitory effect of Nodal on cell proliferation. Taken together, these findings demonstrated that Nodal signaling promotes CCNG2 transcription by upregulating FoxO3a expression, inhibiting FoxO3a phosphorylation and enhancing its synergistic interaction with Smads. These results also suggest
New active analogues of Cucurbita maxima trypsin inhibitor III (CMTI-III) modified in the non-contact region.

Science.gov (United States)

Rózycki, J; Kupryszewski, G; Rolka, K; Ragnarsson, U; Zbyryt, T; Krokoszyńska, I; Wilusz, T

1994-01-01

Four new analogues of trypsin inhibitor CMTI-III(3-28) = [desArg1,desVal2,desGly29]CMTI-III which was recently shown to be fully active, were synthesized by the solid-phase method. The introduction of glycine in position 9 (peptide 1) and Gly-Pro-Gly (peptide 2) and Gly-Pro-Asn (peptide 3) in the regions 17-19 and 23-25, respectively, did not change the antitrypsin activity of all modified peptides. All of these substitutions are presumed to be outside the trypsin-binding loop as judged from the X-ray structure of the complex between beta-trypsin and the related inhibitor CMTI-I. Also the fourth analogue which was substituted in all the positions mentioned, exhibited the full activity.
Indirubin, a component of Ban-Lan-Gen, activates CYP3A4 gene transcription through the human pregnane X receptor.

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Kumagai, Takeshi; Aratsu, Yusuke; Sugawara, Ryosuke; Sasaki, Takamitsu; Miyairi, Shinichi; Nagata, Kiyoshi

2016-04-01

Ban-Lan-Gen is the common name for the dried roots of indigo plants, including Polygonum tinctorium, Isatis indigotica, Isatis tinctoria, and Strobilanthes cusia. Ban-Lan-Gen is frequently used as an anti-inflammatory and an anti-viral for the treatment of hepatitis, influenza, and various types of inflammation. One of the cytochrome P450 (CYP) enzymes, CYP3A4, is responsible for the metabolism of a wide variety of xenobiotics, including an estimated 60% of all clinically used drugs. In this study, we investigated the effect of Ban-Lan-Gen on the transcriptional activation of the CYP3A4 gene. Ban-Lan-Gen extract increased CYP3A4 gene reporter activity in a dose-dependent manner. Indirubin, one of the biologically active ingredients in the Ban-Lan-Gen, also dose-dependently increased CYP3A4 gene reporter activity. Expression of short hairpin RNA for the human pregnane X receptor (hPXR-shRNA) inhibited CYP3A4 gene reporter activity, and overexpression of human PXR increased indirubin- and rifampicin-induced CYP3A4 gene reporter activity. Furthermore, indirubin induced CYP3A4 mRNA expression in HepG2 cells. Taken together, these results indicate that indirubin, a component of Ban-Lan-Gen, activated CYP3A4 gene transcription through the activation of the human PXR. Copyright © 2016. Published by Elsevier Ltd.
Global transcriptional regulatory network for Escherichia coli robustly connects gene expression to transcription factor activities

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Fang, Xin; Sastry, Anand; Mih, Nathan; Kim, Donghyuk; Tan, Justin; Lloyd, Colton J.; Gao, Ye; Yang, Laurence; Palsson, Bernhard O.

2017-01-01

Transcriptional regulatory networks (TRNs) have been studied intensely for >25 y. Yet, even for the Escherichia coli TRN—probably the best characterized TRN—several questions remain. Here, we address three questions: (i) How complete is our knowledge of the E. coli TRN; (ii) how well can we predict gene expression using this TRN; and (iii) how robust is our understanding of the TRN? First, we reconstructed a high-confidence TRN (hiTRN) consisting of 147 transcription factors (TFs) regulating 1,538 transcription units (TUs) encoding 1,764 genes. The 3,797 high-confidence regulatory interactions were collected from published, validated chromatin immunoprecipitation (ChIP) data and RegulonDB. For 21 different TF knockouts, up to 63% of the differentially expressed genes in the hiTRN were traced to the knocked-out TF through regulatory cascades. Second, we trained supervised machine learning algorithms to predict the expression of 1,364 TUs given TF activities using 441 samples. The algorithms accurately predicted condition-specific expression for 86% (1,174 of 1,364) of the TUs, while 193 TUs (14%) were predicted better than random TRNs. Third, we identified 10 regulatory modules whose definitions were robust against changes to the TRN or expression compendium. Using surrogate variable analysis, we also identified three unmodeled factors that systematically influenced gene expression. Our computational workflow comprehensively characterizes the predictive capabilities and systems-level functions of an organism’s TRN from disparate data types. PMID:28874552
WRKY Transcription Factors Involved in Activation of SA Biosynthesis Genes

Directory of Open Access Journals (Sweden)

Bol John F

2011-05-01

Full Text Available Abstract Background Increased defense against a variety of pathogens in plants is achieved through activation of a mechanism known as systemic acquired resistance (SAR. The broad-spectrum resistance brought about by SAR is mediated through salicylic acid (SA. An important step in SA biosynthesis in Arabidopsis is the conversion of chorismate to isochorismate through the action of isochorismate synthase, encoded by the ICS1 gene. Also AVRPPHB SUSCEPTIBLE 3 (PBS3 plays an important role in SA metabolism, as pbs3 mutants accumulate drastically reduced levels of SA-glucoside, a putative storage form of SA. Bioinformatics analysis previously performed by us identified WRKY28 and WRKY46 as possible regulators of ICS1 and PBS3. Results Expression studies with ICS1 promoter::β-glucuronidase (GUS genes in Arabidopsis thaliana protoplasts cotransfected with 35S::WRKY28 showed that over expression of WRKY28 resulted in a strong increase in GUS expression. Moreover, qRT-PCR analyses indicated that the endogenous ICS1 and PBS3 genes were highly expressed in protoplasts overexpressing WRKY28 or WRKY46, respectively. Electrophoretic mobility shift assays indentified potential WRKY28 binding sites in the ICS1 promoter, positioned -445 and -460 base pairs upstream of the transcription start site. Mutation of these sites in protoplast transactivation assays showed that these binding sites are functionally important for activation of the ICS1 promoter. Chromatin immunoprecipitation assays with haemagglutinin-epitope-tagged WRKY28 showed that the region of the ICS1 promoter containing the binding sites at -445 and -460 was highly enriched in the immunoprecipitated DNA. Conclusions The results obtained here confirm results from our multiple microarray co-expression analyses indicating that WRKY28 and WRKY46 are transcriptional activators of ICS1 and PBS3, respectively, and support this in silico screening as a powerful tool for identifying new components of stress
Synthesis of the tritium labelled β-casomorphine analogues 3H-Phe-Pro-Gly-OH and 3H2-Tyr-Pro-3H-Phe-pyrrolidide

International Nuclear Information System (INIS)

Oehlke, J.; Niedrich, H.; Born, I.; Neubert, K.; Mittag, E.

1991-01-01

The precursor peptides H-Phe(I)-Pro-Gly-OH (III) and H-Tyr(I 2 )-Pro-Phe(I)-pyrrolidide (VIII) were synthesized by stepwise elongation from the C-terminal end and by coupling of Boc-Tyr(I 2 )-Pro-OH with H-Phe(I)-pyrrolidide and following deprotection of the Boc-residue respectively. Catalytic dehalotritiation yielded tritated peptides with specific radioactivities of 450 and 1500 GBq/mmol respectively. Cleavage of 3 H 2 -Tyr-Pro- 3 H-Phe-pyrrolidide by dipeptidylpeptidase IV resulted in fragments with specific radioactivities of 950 ( 3 H 2 -Tyr-Pro) and 590 GBq/ mmol ( 3 H-Phe-pyrrolidide). (author)
TRIM45, a novel human RBCC/TRIM protein, inhibits transcriptional activities of ElK-1 and AP-1

International Nuclear Information System (INIS)

Wang Yuequn; Li Yongqing; Qi Xinzhu; Yuan Wuzhou; Ai Jianping; Zhu Chuanbing; Cao Lei; Yang Hong; Liu Fang; Wu Xiushan; Liu Mingyao

2004-01-01

The tripartite motif (TRIM) proteins play important roles in a variety of cellular functions including cell proliferation, differentiation, development, oncogenesis, and apoptosis. In this study, we report the identification and characterization of the human tripartite motif-containing protein 45 (TRIM45), a novel member of the TRIM family, from a human embryonic heart cDNA library. TRIM45 has a predicted 580 amino acid open reading frame, encoding a putative 64-kDa protein. The N-terminal region harbors a RING finger, two B-boxes, and a predicted α-helical coiled-coil domain, which together form the RBCC/TRIM motif found in a large family of proteins, whereas the C-terminal region contains a filamin-type immunoglobulin (IG-FLMN) domain. Northern blot analysis indicates that TRIM45 is expressed in a variety of human adult and embryonic tissues. In the cell, TRIM45 protein is expressed both in cytoplasm and in cell nucleus. Overexpression of TRIM45 in COS-7 cells inhibits the transcriptional activities of ElK-1 and AP-1. These results suggest that TRIM45 may act as a new transcriptional repressor in mitogen-activated protein kinase signaling pathway

Relation of Transcriptional Factors to the Expression and Activity of Cytochrome P450 and UDP-Glucuronosyltransferases 1A in Human Liver: Co-Expression Network Analysis.

Science.gov (United States)

Zhong, Shilong; Han, Weichao; Hou, Chuqi; Liu, Junjin; Wu, Lili; Liu, Menghua; Liang, Zhi; Lin, Haoming; Zhou, Lili; Liu, Shuwen; Tang, Lan

2017-01-01

Cytochrome P450 (CYPs) and UDP-glucuronosyltransferases (UGTs) play important roles in the metabolism of exogenous and endogenous compounds. The gene transcription of CYPs and UGTs can be enhanced or reduced by transcription factors (TFs). This study aims to explore novel TFs involved in the regulatory network of human hepatic UGTs/CYPs. Correlations between the transcription levels of 683 key TFs and CYPs/UGTs in three different human liver expression profiles (n = 640) were calculated first. Supervised weighted correlation network analysis (sWGCNA) was employed to define hub genes among the selected TFs. The relationship among 17 defined TFs, CYPs/UGTs expression, and activity were evaluated in 30 liver samples from Chinese patients. The positive controls (e.g., PPARA, NR1I2, NR1I3) and hub TFs (NFIA, NR3C2, and AR) in the Grey sWGCNA Module were significantly and positively associated with CYPs/UGTs expression. And the cancer- or inflammation-related TFs (TEAD4, NFKB2, and NFKB1) were negatively associated with mRNA expression of CYP2C9/CYP2E1/UGT1A9. Furthermore, the effect of NR1I2, NR1I3, AR, TEAD4, and NFKB2 on CYP450/UGT1A gene transcription translated into moderate influences on enzyme activities. To our knowledge, this is the first study to integrate Gene Expression Omnibus (GEO) datasets and supervised weighted correlation network analysis (sWGCNA) for defining TFs potentially related to CYPs/UGTs. We detected several novel TFs involved in the regulatory network of hepatic CYPs and UGTs in humans. Further validation and investigation may reveal their exact mechanism of CYPs/UGTs regulation.
NF-κB-dependent transcriptional upregulation of cyclin D1 exerts cytoprotection against hypoxic injury upon EGFR activation

International Nuclear Information System (INIS)

Chen, Zhi-Dong; Xu, Liang; Tang, Kan-Kai; Gong, Fang-Xiao; Liu, Jing-Quan; Ni, Yin; Jiang, Ling-Zhi; Hong, Jun; Han, Fang; Li, Qian; Yang, Xiang-Hong; Sun, Ren-Hua; Mo, Shi-Jing

2016-01-01

Apoptosis of neural cells is one of the main pathological features in hypoxic/ischemic brain injury. Nuclear factor-κB (NF-κB) might be a potential therapeutic target for hypoxic/ischemic brain injury since NF-κB has been found to be inactivated after hypoxia exposure, yet the underlying molecular mechanisms of NF-κB inactivation are largely unknown. Here we report that epidermal growth factor receptor (EGFR) activation prevents neuron-like PC12 cells apoptosis in response to hypoxia via restoring NF-κB-dependent transcriptional upregulation of cyclin D1. Functionally, EGFR activation by EGF stimulation mitigates hypoxia-induced PC12 cells apoptosis in both dose- and time-dependent manner. Of note, EGFR activation elevates IKKβ phosphorylation, increases IκBα ubiquitination, promotes P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as upregulates cyclin D1 expression. EGFR activation also abrogates the decrease of IKKβ phosphorylation, reduction of IκBα ubiquitination, blockade of P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as downregulation of cyclin D1 expression induced by hypoxia. Furthermore, NF-κB-dependent upregulation of cyclin D1 is instrumental for the EGFR-mediated cytoprotection against hypoxic apoptosis. In addition, the dephosphorylation of EGFR induced by either EGF siRNA transfection or anti-HB-EGF neutralization antibody treatment enhances hypoxic cytotoxicity, which are attenuated by EGF administration. Our results highlight the essential role of NF-κB-dependent transcriptional upregulation of cyclin D1 in EGFR-mediated cytoprotective effects under hypoxic preconditioning and support further investigation of EGF in clinical trials of patients with hypoxic/ischemic brain injury. - Highlights: • EGFR activation significantly decreases hypoxia-induced PC12 cells injury. • EGFR activation abrogates the transcriptional repression of cyclin D1 induced by hypoxia in a NF
NF-κB-dependent transcriptional upregulation of cyclin D1 exerts cytoprotection against hypoxic injury upon EGFR activation

Energy Technology Data Exchange (ETDEWEB)

Chen, Zhi-Dong [Department of Critical Care Medicine, The First Affiliated Hospital of Huzhou Normal College, Huzhou 313000, Zhejiang (China); Xu, Liang [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China); Tang, Kan-Kai [Department of Critical Care Medicine, The First Affiliated Hospital of Huzhou Normal College, Huzhou 313000, Zhejiang (China); Gong, Fang-Xiao; Liu, Jing-Quan; Ni, Yin; Jiang, Ling-Zhi; Hong, Jun; Han, Fang; Li, Qian; Yang, Xiang-Hong [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China); Sun, Ren-Hua, E-mail: jqin168@hotmail.com [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China); Mo, Shi-Jing, E-mail: msj860307@163.com [Department of Critical Care Medicine, Zhejiang Provincial People’s Hospital, Hangzhou 310000, Zhejiang (China)

2016-09-10

Apoptosis of neural cells is one of the main pathological features in hypoxic/ischemic brain injury. Nuclear factor-κB (NF-κB) might be a potential therapeutic target for hypoxic/ischemic brain injury since NF-κB has been found to be inactivated after hypoxia exposure, yet the underlying molecular mechanisms of NF-κB inactivation are largely unknown. Here we report that epidermal growth factor receptor (EGFR) activation prevents neuron-like PC12 cells apoptosis in response to hypoxia via restoring NF-κB-dependent transcriptional upregulation of cyclin D1. Functionally, EGFR activation by EGF stimulation mitigates hypoxia-induced PC12 cells apoptosis in both dose- and time-dependent manner. Of note, EGFR activation elevates IKKβ phosphorylation, increases IκBα ubiquitination, promotes P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as upregulates cyclin D1 expression. EGFR activation also abrogates the decrease of IKKβ phosphorylation, reduction of IκBα ubiquitination, blockade of P65 nuclear translocation and recruitment at cyclin D1 gene promoter as well as downregulation of cyclin D1 expression induced by hypoxia. Furthermore, NF-κB-dependent upregulation of cyclin D1 is instrumental for the EGFR-mediated cytoprotection against hypoxic apoptosis. In addition, the dephosphorylation of EGFR induced by either EGF siRNA transfection or anti-HB-EGF neutralization antibody treatment enhances hypoxic cytotoxicity, which are attenuated by EGF administration. Our results highlight the essential role of NF-κB-dependent transcriptional upregulation of cyclin D1 in EGFR-mediated cytoprotective effects under hypoxic preconditioning and support further investigation of EGF in clinical trials of patients with hypoxic/ischemic brain injury. - Highlights: • EGFR activation significantly decreases hypoxia-induced PC12 cells injury. • EGFR activation abrogates the transcriptional repression of cyclin D1 induced by hypoxia in a NF
Fibroblast growth factor receptor 3 interacts with and activates TGFβ-activated kinase 1 tyrosine phosphorylation and NFκB signaling in multiple myeloma and bladder cancer.

Directory of Open Access Journals (Sweden)

Lisa Salazar

Full Text Available Cancer is a major public health problem worldwide. In the United States alone, 1 in 4 deaths is due to cancer and for 2013 a total of 1,660,290 new cancer cases and 580,350 cancer-related deaths are projected. Comprehensive profiling of multiple cancer genomes has revealed a highly complex genetic landscape in which a large number of altered genes, varying from tumor to tumor, impact core biological pathways and processes. This has implications for therapeutic targeting of signaling networks in the development of treatments for specific cancers. The NFκB transcription factor is constitutively active in a number of hematologic and solid tumors, and many signaling pathways implicated in cancer are likely connected to NFκB activation. A critical mediator of NFκB activity is TGFβ-activated kinase 1 (TAK1. Here, we identify TAK1 as a novel interacting protein and target of fibroblast growth factor receptor 3 (FGFR3 tyrosine kinase activity. We further demonstrate that activating mutations in FGFR3 associated with both multiple myeloma and bladder cancer can modulate expression of genes that regulate NFκB signaling, and promote both NFκB transcriptional activity and cell adhesion in a manner dependent on TAK1 expression in both cancer cell types. Our findings suggest TAK1 as a potential therapeutic target for FGFR3-associated cancers, and other malignancies in which TAK1 contributes to constitutive NFκB activation.
Adenovirus Protein E4-ORF1 activation of PI3 kinase reveals differential regulation of downstream effector pathways in adipocytes

OpenAIRE

Chaudhary, Natasha; Gonzalez, Eva; Chang, Sung-Hee; Geng, Fuqiang; Rafii, Shahin; Altorki, Nasser K.; McGraw, Timothy E.

2016-01-01

Insulin activation of phosphatidylinositol 3-kinase (PI3K) regulates metabolism, including the translocation of the Glut4 glucose transporter to the plasma membrane and inactivation of the FoxO1 transcription factor. Adenoviral protein E4-ORF1 stimulates cellular glucose metabolism by mimicking growth-factor activation of PI3K. We have used E4-ORF1 as a tool to dissect PI3K-mediated signaling in adipocytes. E4-ORF1 activation of PI3K in adipocytes recapitulates insulin regulation of FoxO1 but...
Triptolide inhibits transcription of hTERT through down-regulation of transcription factor specificity protein 1 in primary effusion lymphoma cells

Energy Technology Data Exchange (ETDEWEB)

Long, Cong; Wang, Jingchao [Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071 (China); Guo, Wei [Department of Pathology and Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071 (China); Wang, Huan; Wang, Chao; Liu, Yu [Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071 (China); Sun, Xiaoping, E-mail: xsun6@whu.edu.cn [Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071 (China); State Key Laboratory of Virology, Wuhan University, Wuhan, 430072 (China)

2016-01-01

Primary effusion lymphoma (PEL) is a rare and aggressive non-Hodgkin's lymphoma. Human telomerase reverse transcriptase (hTERT), a key component responsible for the regulation of telomerase activity, plays important roles in cellular immortalization and cancer development. Triptolide purified from Tripterygium extracts displays a broad-spectrum bioactivity profile, including immunosuppressive, anti-inflammatory, and anti-tumor. In this study, it is investigated whether triptolide reduces hTERT expression and suppresses its activity in PEL cells. The mRNA and protein levels of hTERT were examined by real time-PCR and Western blotting, respectively. The activity of hTERT promoter was determined by Dual luciferase reporter assay. Our results demonstrated that triptolide decreased expression of hTERT at both mRNA and protein levels. Further gene sequence analysis indicated that the activity of hTERT promoter was suppressed by triptolide. Triptolide also reduced the half-time of hTERT. Additionally, triptolide inhibited the expression of transcription factor specificity protein 1(Sp1) in PEL cells. Furthermore, knock-down of Sp1 by using specific shRNAs resulted in down-regulation of hTERT transcription and protein expression levels. Inhibition of Sp1 by specific shRNAs enhanced triptolide-induced cell growth inhibition and apoptosis. Collectively, our results demonstrate that the inhibitory effect of triptolide on hTERT transcription is possibly mediated by inhibition of transcription factor Sp1 in PEL cells. - Highlights: • Triptolide reduces expression of hTERT by decreasing its transcription level. • Triptolide reduces promoter activity and stability of hTERT. • Triptolide down-regulates expression of Sp1. • Special Sp1 shRNAs inhibit transcription and protein expression of hTERT. • Triptolide and Sp1 shRNA2 induce cell proliferation inhibition and apoptosis.
Reactivation of Latent HIV-1 Expression by Engineered TALE Transcription Factors.

Science.gov (United States)

Perdigão, Pedro; Gaj, Thomas; Santa-Marta, Mariana; Barbas, Carlos F; Goncalves, Joao

2016-01-01

The presence of replication-competent HIV-1 -which resides mainly in resting CD4+ T cells--is a major hurdle to its eradication. While pharmacological approaches have been useful for inducing the expression of this latent population of virus, they have been unable to purge HIV-1 from all its reservoirs. Additionally, many of these strategies have been associated with adverse effects, underscoring the need for alternative approaches capable of reactivating viral expression. Here we show that engineered transcriptional modulators based on customizable transcription activator-like effector (TALE) proteins can induce gene expression from the HIV-1 long terminal repeat promoter, and that combinations of TALE transcription factors can synergistically reactivate latent viral expression in cell line models of HIV-1 latency. We further show that complementing TALE transcription factors with Vorinostat, a histone deacetylase inhibitor, enhances HIV-1 expression in latency models. Collectively, these findings demonstrate that TALE transcription factors are a potentially effective alternative to current pharmacological routes for reactivating latent virus and that combining synthetic transcriptional activators with histone deacetylase inhibitors could lead to the development of improved therapies for latent HIV-1 infection.
Reactivation of Latent HIV-1 Expression by Engineered TALE Transcription Factors.

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Pedro Perdigão

Full Text Available The presence of replication-competent HIV-1 -which resides mainly in resting CD4+ T cells--is a major hurdle to its eradication. While pharmacological approaches have been useful for inducing the expression of this latent population of virus, they have been unable to purge HIV-1 from all its reservoirs. Additionally, many of these strategies have been associated with adverse effects, underscoring the need for alternative approaches capable of reactivating viral expression. Here we show that engineered transcriptional modulators based on customizable transcription activator-like effector (TALE proteins can induce gene expression from the HIV-1 long terminal repeat promoter, and that combinations of TALE transcription factors can synergistically reactivate latent viral expression in cell line models of HIV-1 latency. We further show that complementing TALE transcription factors with Vorinostat, a histone deacetylase inhibitor, enhances HIV-1 expression in latency models. Collectively, these findings demonstrate that TALE transcription factors are a potentially effective alternative to current pharmacological routes for reactivating latent virus and that combining synthetic transcriptional activators with histone deacetylase inhibitors could lead to the development of improved therapies for latent HIV-1 infection.
Enhanced oxygen consumption in Herbaspirillum seropedicae fnr mutants leads to increased NifA mediated transcriptional activation.

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Batista, Marcelo Bueno; Wassem, Roseli; Pedrosa, Fábio de Oliveira; de Souza, Emanuel Maltempi; Dixon, Ray; Monteiro, Rose Adele

2015-05-07

Orthologous proteins of the Crp/Fnr family have been previously implicated in controlling expression and/or activity of the NifA transcriptional activator in some diazotrophs. This study aimed to address the role of three Fnr-like proteins from H. seropedicae SmR1 in controlling NifA activity and consequent NifA-mediated transcription activation. The activity of NifA-dependent transcriptional fusions (nifA::lacZ and nifB::lacZ) was analysed in a series of H. seropedicae fnr deletion mutant backgrounds. We found that combined deletions in both the fnr1 and fnr3 genes lead to higher expression of both the nifA and nifB genes and also an increased level of nifH transcripts. Expression profiles of nifB under different oxygen concentrations, together with oxygen consumption measurements suggest that the triple fnr mutant has higher respiratory activity when compared to the wild type, which we believe to be responsible for greater stability of the oxygen sensitive NifA protein. This conclusion was further substantiated by measuring the levels of NifA protein and its activity in fnr deletion strains in comparison with the wild-type. Fnr proteins are indirectly involved in controlling the activity of NifA in H. seropedicae, probably as a consequence of their influence on respiratory activity in relation to oxygen availability. Additionally we can suggest that there is some redundancy in the physiological function of the three Fnr paralogs in this organism, since altered respiration and effects on NifA activity are only observed in deletion strains lacking both fnr1 and fnr3.
ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana

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Jensen, Michael Krogh; Lindemose, Søren; De Masi, Federico

2013-01-01

ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT[A,C,G...... abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis....
Disruption of histone modification and CARM1 recruitment by arsenic represses transcription at glucocorticoid receptor-regulated promoters.

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Barr, Fiona D; Krohmer, Lori J; Hamilton, Joshua W; Sheldon, Lynn A

2009-08-26

Chronic exposure to inorganic arsenic (iAs) found in the environment is one of the most significant and widespread environmental health risks in the U.S. and throughout the world. It is associated with a broad range of health effects from cancer to diabetes as well as reproductive and developmental anomalies. This diversity of diseases can also result from disruption of metabolic and other cellular processes regulated by steroid hormone receptors via aberrant transcriptional regulation. Significantly, exposure to iAs inhibits steroid hormone-mediated gene activation. iAs exposure is associated with disease, but is also used therapeutically to treat specific cancers complicating an understanding of iAs action. Transcriptional activation by steroid hormone receptors is accompanied by changes in histone and non-histone protein post-translational modification (PTM) that result from the enzymatic activity of coactivator and corepressor proteins such as GRIP1 and CARM1. This study addresses how iAs represses steroid receptor-regulated gene transcription. PTMs on histones H3 and H4 at the glucocorticoid receptor (GR)-activated mouse mammary tumor virus (MMTV) promoter were identified by chromatin immunoprecipitation analysis following exposure to steroid hormone+/-iAs. Histone H3K18 and H3R17 amino acid residues had significantly different patterns of PTMs after treatment with iAs. Promoter interaction of the coactivator CARM1 was disrupted, but the interaction of GRIP1, a p160 coactivator through which CARM1 interacts with a promoter, was intact. Over-expression of CARM1 was able to fully restore and GRIP1 partially restored iAs-repressed transcription indicating that these coactivators are functionally associated with iAs-mediated transcriptional repression. Both are essential for robust transcription at steroid hormone regulated genes and both are associated with disease when inappropriately expressed. We postulate that iAs effects on CARM1 and GRIP1 may underlie some
Constitutively active RAS signaling reduces 1,25 dihydroxyvitamin D-mediated gene transcription in intestinal epithelial cells by reducing vitamin D receptor expression.

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DeSmet, Marsha L; Fleet, James C

2017-10-01

High vitamin D status is associated with reduced colon cancer risk but these studies ignore the diversity in the molecular etiology of colon cancer. RAS activating mutations are common in colon cancer and they activate pro-proliferative signaling pathways. We examined the impact of RAS activating mutations on 1,25 dihydroxyvitamin D (1,25(OH) 2 D)-mediated gene expression in cultured colon and intestinal cell lines. Transient transfection of Caco-2 cells with a constitutively active mutant K-RAS (G12 V) significantly reduced 1,25(OH) 2 D-induced activity of both a human 25-hydroxyvitamin D, 24 hydroxyase (CYP24A1) promoter-luciferase and an artificial 3X vitamin D response element (VDRE) promoter-luciferase reporter gene. Young Adult Mouse Colon (YAMC) and Rat Intestinal Epithelial (RIE) cell lines with stable expression of mutant H-RAS had suppressed 1,25(OH) 2 D-mediated induction of CYP24A1 mRNA. The RAS effects were associated with lower Vitamin D receptor (VDR) mRNA and protein levels in YAMC and RIE cells and they could be partially reversed by VDR overexpression. RAS-mediated suppression of VDR levels was not due to either reduced VDR mRNA stability or increased VDR gene methylation. However, chromatin accessibility to the VDR gene at the proximal promoter (-300bp), an enhancer region at -6kb, and an enhancer region located in exon 3 was significantly reduced in RAS transformed YAMC cells (YAMC-RAS). These data show that constitutively active RAS signaling suppresses 1,25(OH) 2 D-mediated gene transcription in colon epithelial cells by reducing VDR gene transcription but the mechanism for this suppression is not yet known. These data suggest that cancers with RAS-activating mutations may be less responsive to vitamin D mediated treatment or chemoprevention. Copyright © 2017 Elsevier Ltd. All rights reserved.
Distinct structural features of TFAM drive mitochondrial DNA packaging versus transcriptional activation.

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Ngo, Huu B; Lovely, Geoffrey A; Phillips, Rob; Chan, David C

2014-01-01

TFAM (transcription factor A, mitochondrial) is a DNA-binding protein that activates transcription at the two major promoters of mitochondrial DNA (mtDNA)--the light strand promoter (LSP) and the heavy strand promoter 1 (HSP1). Equally important, it coats and packages the mitochondrial genome. TFAM has been shown to impose a U-turn on LSP DNA; however, whether this distortion is relevant at other sites is unknown. Here we present crystal structures of TFAM bound to HSP1 and to nonspecific DNA. In both, TFAM similarly distorts the DNA into a U-turn. Yet, TFAM binds to HSP1 in the opposite orientation from LSP explaining why transcription from LSP requires DNA bending, whereas transcription at HSP1 does not. Moreover, the crystal structures reveal dimerization of DNA-bound TFAM. This dimerization is dispensable for DNA bending and transcriptional activation but is important in DNA compaction. We propose that TFAM dimerization enhances mitochondrial DNA compaction by promoting looping of the DNA.
MrkH, a novel c-di-GMP-dependent transcriptional activator, controls Klebsiella pneumoniae biofilm formation by regulating type 3 fimbriae expression.

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Jonathan J Wilksch

2011-08-01

Full Text Available Klebsiella pneumoniae causes significant morbidity and mortality worldwide, particularly amongst hospitalized individuals. The principle mechanism for pathogenesis in hospital environments involves the formation of biofilms, primarily on implanted medical devices. In this study, we constructed a transposon mutant library in a clinical isolate, K. pneumoniae AJ218, to identify the genes and pathways implicated in biofilm formation. Three mutants severely defective in biofilm formation contained insertions within the mrkABCDF genes encoding the main structural subunit and assembly machinery for type 3 fimbriae. Two other mutants carried insertions within the yfiN and mrkJ genes, which encode GGDEF domain- and EAL domain-containing c-di-GMP turnover enzymes, respectively. The remaining two isolates contained insertions that inactivated the mrkH and mrkI genes, which encode for novel proteins with a c-di-GMP-binding PilZ domain and a LuxR-type transcriptional regulator, respectively. Biochemical and functional assays indicated that the effects of these factors on biofilm formation accompany concomitant changes in type 3 fimbriae expression. We mapped the transcriptional start site of mrkA, demonstrated that MrkH directly activates transcription of the mrkA promoter and showed that MrkH binds strongly to the mrkA regulatory region only in the presence of c-di-GMP. Furthermore, a point mutation in the putative c-di-GMP-binding domain of MrkH completely abolished its function as a transcriptional activator. In vivo analysis of the yfiN and mrkJ genes strongly indicated their c-di-GMP-specific function as diguanylate cyclase and phosphodiesterase, respectively. In addition, in vitro assays showed that purified MrkJ protein has strong c-di-GMP phosphodiesterase activity. These results demonstrate for the first time that c-di-GMP can function as an effector to stimulate the activity of a transcriptional activator, and explain how type 3 fimbriae
Pou1f1, the key transcription factor related to somatic growth in tilapia (Orechromis niloticus), is regulated by two independent post-transcriptional regulation mechanisms.

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Wang, Dongfang; Qin, Jingkai; Jia, Jirong; Yan, Peipei; Li, Wensheng

2017-01-29

This study aims to determine the post-transcriptional regulation mechanism of the transcription factor pou1f1 (pou class 1 homeobox 1), which is the key gene for pituitary development, somatic growth in vertebrates, and transcription of several hormone genes in teleost fish. MicroRNA miR-223-3p was identified as a bona fide target of pou1f; overexpression of miR-223-3p in primary pituitary cells led to the down-regulation of pou1f1 and downstream genes, and inhibition of miR-223-3p led to the up-regulation of pou1f1 in Nile tilapia dispersed primary pituitary cells. An adenylate-uridylate-rich element (AU-Rich element) was found in the 3'UTR of pou1f1 mRNA, and deletion of the AU-Rich element led to slower mRNA decay and therefore more protein output. A potential mutual relationship between miR-223-3p and the AU-rich element was also investigated, and the results demonstrated that with or without the AU-Rich element, miR-223-3p induced the up-regulation of a reporter system under serum starvation conditions, indicating that miR-223-3p and the AU-Rich element function independent of each other. This study is the first to investigate the post-transcriptional mechanism of pou1f1, which revealed that miR-223-3p down-regulated pou1f1 and downstream gene expressions, and the AU-Rich element led to rapid decay of pou1f1 mRNA. MicroRNA miR-223-3p and the AU-Rich element co-regulated the post-transcriptional expression of pou1f1 independently in Nile tilapia, demonstrating that pou1f1 is under the control of a dual post-transcription regulation mechanism. Copyright © 2016 Elsevier Inc. All rights reserved.
Functional characterization of tobacco transcription factor TGA2.1

DEFF Research Database (Denmark)

Kegler, C.; Lenk, I.; Krawczyk, S.

2004-01-01

Activation sequence-1 (as-1)-like regulatory cis elements mediate transcriptional activation in response to increased levels of plant signalling molecules auxin and salicylic acid (SA). Our earlier work has shown that tobacco cellular as-1-binding complex SARP (salicylic acid responsive protein...
Adenovirus DNA binding protein inhibits SrCap-activated CBP and CREB-mediated transcription

International Nuclear Information System (INIS)

Xu Xiequn; Tarakanova, Vera; Chrivia, John; Yaciuk, Peter

2003-01-01

The SNF2-related CBP activator protein (SrCap) is a potent activator of transcription mediated by CBP and CREB. We have previously demonstrated that the Adenovirus 2 DNA Binding Protein (DBP) binds to SrCap and inhibits the transcription mediated by the carboxyl-terminal region of SrCap (amino acids 1275-2971). We report here that DBP inhibits the ability of full-length SrCap (1-2971) to activate transcription mediated by Gal-CREB and Gal-CBP. In addition, DBP also inhibits the ability of SrCap to enhance Protein Kinase A (PKA) activated transcription of the enkaphalin promoter. DBP was found to dramatically inhibit transcription of a mammalian two-hybrid system that was dependent on the interaction of SrCap and CBP binding domains. We also found that DBP has no effect on transcription mediated by a transcriptional activator that is not related to SrCap, indicating that our reported transcriptional inhibition is specific for SrCap and not due to nonspecific effects of DBP's DNA binding activity on the CAT reporter plasmid. Taken together, these results suggest a model in which DBP inhibits cellular transcription mediated by the interaction between SrCap and CBP
The Calmodulin-Binding Transcription Activator CAMTA1 Is Required for Long-Term Memory Formation in Mice

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Bas-Orth, Carlos; Tan, Yan-Wei; Oliveira, Ana M. M.; Bengtson, C. Peter; Bading, Hilmar

2016-01-01

The formation of long-term memory requires signaling from the synapse to the nucleus to mediate neuronal activity-dependent gene transcription. Synapse-to-nucleus communication is initiated by influx of calcium ions through synaptic NMDA receptors and/or L-type voltage-gated calcium channels and involves the activation of transcription factors by…
Short curcumin treatment modulates oxidative stress, arginase activity, aberrant crypt foci, and TGF-β1 and HES-1 transcripts in 1,2-dimethylhydrazine-colon carcinogenesis in mice

International Nuclear Information System (INIS)

Bounaama, Abdelkader; Djerdjouri, Bahia; Laroche-Clary, Audrey; Le Morvan, Valérie; Robert, Jacques

2012-01-01

Highlights: ► 1,2-Dimethylhydrazine (DMH) toxicity was driven by oxidative stress. ► Arginase activity correlated to aberrant crypt foci (ACF). ► Curcumin diet restored redox status and induced apoptosis of dysplastic ACF. ► Curcumin reduced arginase activity and up regulated TGF-β1 and HES-1 transcripts. -- Abstract: This study investigated the effect of short curcumin treatment, a natural antioxidant on 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) in mice. The incidence of aberrant crypt foci (ACF) was 100%, with 54 ± 6 per colon, 10 weeks after the first DMH injection and reached 67 ± 12 per colon after 12 weeks. A high level of undifferentiated goblet cells and a weak apoptotic activity were shown in dysplastic ACF. The morphological alterations of colonic mucosa were associated to severe oxidative stress ratio with 43% increase in malondialdehyde vs. 36% decrease in GSH. DMH also increased inducible nitric synthase (iNOS) mRNA transcripts (250%), nitrites level (240%) and arginase activity (296%), leading to nitrosative stress and cell proliferation. Curcumin treatment, starting at week 10 post-DMH injection for 14 days, reduced the number of ACF (40%), iNOS expression (25%) and arginase activity (73%), and improved redox status by approximately 46%, compared to DMH-treated mice. Moreover, curcumin induced apoptosis of dysplastic ACF cells without restoring goblet cells differentiation. Interestingly, curcumin induced a parallel increase in TGF-β1 and HES-1 transcripts (42% and 26%, respectively). In conclusion, the protective effect of curcumin was driven by the reduction of arginase activity and nitrosative stress. The up regulation of TGF-β1 and HES-1 expression by curcumin suggests for the first time, a potential interplay between these signalling pathways in the chemoprotective mechanism of curcumin.
Onset and organ specificity of Tk2 deficiency depends on Tk1 down-regulation and transcriptional compensation.

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Dorado, Beatriz; Area, Estela; Akman, Hasan O; Hirano, Michio

2011-01-01

Deficiency of thymidine kinase 2 (TK2) is a frequent cause of isolated myopathy or encephalomyopathy in children with mitochondrial DNA (mtDNA) depletion. To determine the bases of disease onset, organ specificity and severity of TK2 deficiency, we have carefully characterized Tk2 H126N knockin mice (Tk2-/-). Although normal until postnatal day 8, Tk2-/- mice rapidly develop fatal encephalomyopathy between postnatal days 10 and 13. We have observed that wild-type Tk2 activity is constant in the second week of life, while Tk1 activity decreases significantly between postnatal days 8 and 13. The down-regulation of Tk1 activity unmasks Tk2 deficiency in Tk2-/- mice and correlates with the onset of mtDNA depletion in the brain and the heart. Resistance to pathology in Tk2 mutant organs depends on compensatory mechanisms to the reduced mtDNA level. Our analyses at postnatal day 13 have revealed that Tk2-/- heart significantly increases mitochondrial transcript levels relative to the mtDNA content. This transcriptional compensation allows the heart to maintain normal levels of mtDNA-encoded proteins. The up-regulation in mitochondrial transcripts is not due to increased expression of the master mitochondrial biogenesis regulators peroxisome proliferator-activated receptor-gamma coactivator 1 alpha and nuclear respiratory factors 1 and 2, or to enhanced expression of the mitochondrial transcription factors A, B1 or B2. Instead, Tk2-/- heart compensates for mtDNA depletion by down-regulating the expression of the mitochondrial transcriptional terminator transcription factor 3 (MTERF3). Understanding the molecular mechanisms that allow Tk2 mutant organs to be spared may help design therapies for Tk2 deficiency.

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