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Sample records for suppresses transcriptional activity

  1. E-cadherin is transcriptionally activated via suppression of ZEB1 transcriptional repressor by small RNA-mediated gene silencing.

    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.

  2. MicroRNA-214 suppresses gluconeogenesis by targeting activating transcriptional factor 4.

    Li, Kai; Zhang, Jin; Yu, Junjie; Liu, Bin; Guo, Yajie; Deng, Jiali; Chen, Shanghai; Wang, Chunxia; Guo, Feifan

    2015-03-27

    Although the gluconeogenesis pathway is already a target for the treatment of type 2 diabetes, the potential role of microRNAs (miRNAs) in gluconeogenesis remains unclear. Here, we investigated the physiological functions of miR-214 in gluconeogenesis. The expression of miR-214 was suppressed by glucagon via protein kinase A signaling in primary hepatocytes, and miR-214 was down-regulated in the livers of fasted, high fat diet-induced diabetic and leptin receptor-mutated (db/db) mice. The overexpression of miR-214 in primary hepatocytes suppressed glucose production, and silencing miR-214 reversed this effect. Gluconeogenesis was suppressed in the livers of mice injected with an adenovirus expressing miR-214 (Ad-miR-214). Additionally, Ad-miR-214 alleviated high fat diet-induced elevation of gluconeogenesis and hyperglycemia. Furthermore, we found that activating transcription factor 4 (ATF4), a reported target of miR-214, can reverse the suppressive effect of miR-214 on gluconeogenesis in primary hepatocytes, and this suppressive effect was blocked in liver-specific ATF4 knock-out mice. ATF4 regulated gluconeogenesis via affecting forkhead box protein O1 (FOXO1) transcriptional activity. Finally, liver-specific miR-214 transgenic mice exhibited suppressed gluconeogenesis and reduced expression of ATF4, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase in liver. Taken together, our results suggest that the miR-214-ATF4 axis is a novel pathway for the regulation of hepatic gluconeogenesis. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. MicroRNA-214 Suppresses Gluconeogenesis by Targeting Activating Transcriptional Factor 4*

    Li, Kai; Zhang, Jin; Yu, Junjie; Liu, Bin; Guo, Yajie; Deng, Jiali; Chen, Shanghai; Wang, Chunxia; Guo, Feifan

    2015-01-01

    Although the gluconeogenesis pathway is already a target for the treatment of type 2 diabetes, the potential role of microRNAs (miRNAs) in gluconeogenesis remains unclear. Here, we investigated the physiological functions of miR-214 in gluconeogenesis. The expression of miR-214 was suppressed by glucagon via protein kinase A signaling in primary hepatocytes, and miR-214 was down-regulated in the livers of fasted, high fat diet-induced diabetic and leptin receptor-mutated (db/db) mice. The overexpression of miR-214 in primary hepatocytes suppressed glucose production, and silencing miR-214 reversed this effect. Gluconeogenesis was suppressed in the livers of mice injected with an adenovirus expressing miR-214 (Ad-miR-214). Additionally, Ad-miR-214 alleviated high fat diet-induced elevation of gluconeogenesis and hyperglycemia. Furthermore, we found that activating transcription factor 4 (ATF4), a reported target of miR-214, can reverse the suppressive effect of miR-214 on gluconeogenesis in primary hepatocytes, and this suppressive effect was blocked in liver-specific ATF4 knock-out mice. ATF4 regulated gluconeogenesis via affecting forkhead box protein O1 (FOXO1) transcriptional activity. Finally, liver-specific miR-214 transgenic mice exhibited suppressed gluconeogenesis and reduced expression of ATF4, phosphoenolpyruvate carboxykinase, and glucose-6-phosphatase in liver. Taken together, our results suggest that the miR-214-ATF4 axis is a novel pathway for the regulation of hepatic gluconeogenesis. PMID:25657009

  4. USP10 Antagonizes c-Myc Transcriptional Activation through SIRT6 Stabilization to Suppress Tumor Formation

    Zhenghong Lin

    2013-12-01

    Full Text Available The reduced protein expression of SIRT6 tumor suppressor is involved in tumorigenesis. The molecular mechanisms underlying SIRT6 protein downregulation in human cancers remain unknown. Using a proteomic approach, we have identified the ubiquitin-specific peptidase USP10, another tumor suppressor, as one of the SIRT6-interacting proteins. USP10 suppresses SIRT6 ubiquitination to protect SIRT6 from proteasomal degradation. USP10 antagonizes the transcriptional activity of the c-Myc oncogene through SIRT6, as well as p53, to inhibit cell-cycle progression, cancer cell growth, and tumor formation. To support this conclusion, we detected significant reductions in both USP10 and SIRT6 protein expression in human colon cancers. Our study discovered crosstalk between two tumor-suppressive genes in regulating cell-cycle progression and proliferation and showed that dysregulated USP10 function promotes tumorigenesis through SIRT6 degradation.

  5. Kurarinol induces hepatocellular carcinoma cell apoptosis through suppressing cellular signal transducer and activator of transcription 3 signaling

    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

  6. Activation of HIV Transcription with Short-Course Vorinostat in HIV-Infected Patients on Suppressive Antiretroviral Therapy

    Solomon, Ajantha; Ghneim, Khader; Ahlers, Jeffrey; Cameron, Mark J.; Smith, Miranda Z.; Spelman, Tim; McMahon, James; Velayudham, Pushparaj; Brown, Gregor; Roney, Janine; Watson, Jo; Prince, Miles H.; Hoy, Jennifer F.; Chomont, Nicolas; Fromentin, Rémi; Procopio, Francesco A.; Zeidan, Joumana; Palmer, Sarah; Odevall, Lina; Johnstone, Ricky W.; Martin, Ben P.; Sinclair, Elizabeth; Deeks, Steven G.; Hazuda, Daria J.; Cameron, Paul U.; Sékaly, Rafick-Pierre; Lewin, Sharon R.

    2014-01-01

    Human immunodeficiency virus (HIV) persistence in latently infected resting memory CD4+ T-cells is the major barrier to HIV cure. Cellular histone deacetylases (HDACs) are important in maintaining HIV latency and histone deacetylase inhibitors (HDACi) may reverse latency by activating HIV transcription from latently infected CD4+ T-cells. We performed a single arm, open label, proof-of-concept study in which vorinostat, a pan-HDACi, was administered 400 mg orally once daily for 14 days to 20 HIV-infected individuals on suppressive antiretroviral therapy (ART). The primary endpoint was change in cell associated unspliced (CA-US) HIV RNA in total CD4+ T-cells from blood at day 14. The study is registered at ClinicalTrials.gov (NCT01365065). Vorinostat was safe and well tolerated and there were no dose modifications or study drug discontinuations. CA-US HIV RNA in blood increased significantly in 18/20 patients (90%) with a median fold change from baseline to peak value of 7.4 (IQR 3.4, 9.1). CA-US RNA was significantly elevated 8 hours post drug and remained elevated 70 days after last dose. Significant early changes in expression of genes associated with chromatin remodeling and activation of HIV transcription correlated with the magnitude of increased CA-US HIV RNA. There were no statistically significant changes in plasma HIV RNA, concentration of HIV DNA, integrated DNA, inducible virus in CD4+ T-cells or markers of T-cell activation. Vorinostat induced a significant and sustained increase in HIV transcription from latency in the majority of HIV-infected patients. However, additional interventions will be needed to efficiently induce virus production and ultimately eliminate latently infected cells. Trial Registration ClinicalTrials.gov NCT01365065 PMID:25393648

  7. Activation of HIV transcription with short-course vorinostat in HIV-infected patients on suppressive antiretroviral therapy.

    Julian H Elliott

    2014-10-01

    Full Text Available Human immunodeficiency virus (HIV persistence in latently infected resting memory CD4+ T-cells is the major barrier to HIV cure. Cellular histone deacetylases (HDACs are important in maintaining HIV latency and histone deacetylase inhibitors (HDACi may reverse latency by activating HIV transcription from latently infected CD4+ T-cells. We performed a single arm, open label, proof-of-concept study in which vorinostat, a pan-HDACi, was administered 400 mg orally once daily for 14 days to 20 HIV-infected individuals on suppressive antiretroviral therapy (ART. The primary endpoint was change in cell associated unspliced (CA-US HIV RNA in total CD4+ T-cells from blood at day 14. The study is registered at ClinicalTrials.gov (NCT01365065. Vorinostat was safe and well tolerated and there were no dose modifications or study drug discontinuations. CA-US HIV RNA in blood increased significantly in 18/20 patients (90% with a median fold change from baseline to peak value of 7.4 (IQR 3.4, 9.1. CA-US RNA was significantly elevated 8 hours post drug and remained elevated 70 days after last dose. Significant early changes in expression of genes associated with chromatin remodeling and activation of HIV transcription correlated with the magnitude of increased CA-US HIV RNA. There were no statistically significant changes in plasma HIV RNA, concentration of HIV DNA, integrated DNA, inducible virus in CD4+ T-cells or markers of T-cell activation. Vorinostat induced a significant and sustained increase in HIV transcription from latency in the majority of HIV-infected patients. However, additional interventions will be needed to efficiently induce virus production and ultimately eliminate latently infected cells.ClinicalTrials.gov NCT01365065.

  8. Suppression of sterol 27-hydroxylase mRNA and transcriptional activity by bile acids in cultured rat hepatocytes

    Twisk, J.; Wit, E.C.M. de; Princen, H.M.G.

    1995-01-01

    In previous work we have demonstrated suppression of cholesterol 7α-hydroxylase by bile acids at the level of mRNA and transcription, resulting in a similar decline in bile acid synthesis in cultured rat hepatocytes. In view of the substantial contribution of the 'alternative' or '27-hydroxylase'

  9. ZNF328, a novel human zinc-finger protein, suppresses transcriptional activities of SRE and AP-1

    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

  10. Suppression of PTEN transcription by UVA

    Zhao, Baozhong; Ming, Mei; He, Yu-Ying

    2012-01-01

    Although UVA has different physical and biological targets than UVB, the contribution of UVA to skin cancer susceptibility and its molecular basis remain largely unknown. Here we show that chronic UVA radiation suppresses PTEN expression at the mRNA level. Subchronic and acute UVA radiation also down-regulated PTEN in normal human epidermal keratinocytes, skin culture and mouse skin. At the molecular level, chronic UVA radiation decreased the transcriptional activity of the PTEN promoter in a methylation-independent manner, while it had no effect on the protein stability or mRNA stability of PTEN. In contrast, we found that UVA-induced activation of the Ras/ERK/AKT and NF-κB pathways plays an important role in UV-induced PTEN down-regulation. Inhibiting ERK or AKT increases PTEN expression. Our findings may provide unique insights into PTEN down-regulation as a critical component of UVA’s molecular impact during keratinocyte transformation. PMID:23129115

  11. Caloric Restriction Mimetic 2-Deoxyglucose Alleviated Inflammatory Lung Injury via Suppressing Nuclear Pyruvate Kinase M2–Signal Transducer and Activator of Transcription 3 Pathway

    Kai Hu

    2018-03-01

    Full Text Available Inflammation is an energy-intensive process, and caloric restriction (CR could provide anti-inflammatory benefits. CR mimetics (CRM, such as the glycolytic inhibitor 2-deoxyglucose (2-DG, mimic the beneficial effects of CR without inducing CR-related physiologic disturbance. This study investigated the potential anti-inflammatory benefits of 2-DG and the underlying mechanisms in mice with lipopolysaccharide (LPS-induced lethal endotoxemia. The results indicated that pretreatment with 2-DG suppressed LPS-induced elevation of tumor necrosis factor alpha and interleukin 6. It also suppressed the upregulation of myeloperoxidase, attenuated Evans blue leakage, alleviated histological abnormalities in the lung, and improved the survival of LPS-challenged mice. Treatment with 2-DG had no obvious effects on the total level of pyruvate kinase M2 (PKM2, but it significantly suppressed LPS-induced elevation of PKM2 in the nuclei. Prevention of PKM2 nuclear accumulation by ML265 mimicked the anti-inflammatory benefits of 2-DG. In addition, treatment with 2-DG or ML265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3. Inhibition of STAT3 by stattic suppressed LPS-induced inflammatory injury. Interestingly, posttreatment with 2-DG at the early stage post-LPS challenge also improved the survival of the experimental animals. This study found that treatment with 2-DG, a representative CRM, provided anti-inflammatory benefits in lethal inflammation. The underlying mechanisms included suppressed nuclear PKM2-STAT3 pathway. These data suggest that 2-DG might have potential value in the early intervention of lethal inflammation.

  12. Caloric Restriction Mimetic 2-Deoxyglucose Alleviated Inflammatory Lung Injury via Suppressing Nuclear Pyruvate Kinase M2-Signal Transducer and Activator of Transcription 3 Pathway.

    Hu, Kai; Yang, Yongqiang; Lin, Ling; Ai, Qing; Dai, Jie; Fan, Kerui; Ge, Pu; Jiang, Rong; Wan, Jingyuan; Zhang, Li

    2018-01-01

    Inflammation is an energy-intensive process, and caloric restriction (CR) could provide anti-inflammatory benefits. CR mimetics (CRM), such as the glycolytic inhibitor 2-deoxyglucose (2-DG), mimic the beneficial effects of CR without inducing CR-related physiologic disturbance. This study investigated the potential anti-inflammatory benefits of 2-DG and the underlying mechanisms in mice with lipopolysaccharide (LPS)-induced lethal endotoxemia. The results indicated that pretreatment with 2-DG suppressed LPS-induced elevation of tumor necrosis factor alpha and interleukin 6. It also suppressed the upregulation of myeloperoxidase, attenuated Evans blue leakage, alleviated histological abnormalities in the lung, and improved the survival of LPS-challenged mice. Treatment with 2-DG had no obvious effects on the total level of pyruvate kinase M2 (PKM2), but it significantly suppressed LPS-induced elevation of PKM2 in the nuclei. Prevention of PKM2 nuclear accumulation by ML265 mimicked the anti-inflammatory benefits of 2-DG. In addition, treatment with 2-DG or ML265 suppressed the phosphorylation of nuclear signal transducer and activator of transcription 3 (STAT3). Inhibition of STAT3 by stattic suppressed LPS-induced inflammatory injury. Interestingly, posttreatment with 2-DG at the early stage post-LPS challenge also improved the survival of the experimental animals. This study found that treatment with 2-DG, a representative CRM, provided anti-inflammatory benefits in lethal inflammation. The underlying mechanisms included suppressed nuclear PKM2-STAT3 pathway. These data suggest that 2-DG might have potential value in the early intervention of lethal inflammation.

  13. Silibinin and its 2,3-dehydro-derivative inhibit basal cell carcinoma growth via suppression of mitogenic signaling and transcription factors activation.

    Tilley, Cynthia; Deep, Gagan; Agarwal, Chapla; Wempe, Michael F; Biedermann, David; Valentová, Kateřina; Kren, Vladimir; Agarwal, Rajesh

    2016-01-01

    Basal cell carcinoma (BCC) is the most common cancer worldwide, and its current treatment options are insufficient and toxic. Surprisingly, unlike several other malignancies, chemopreventive efforts against BCC are almost lacking. Silibinin, a natural agent from milk thistle seeds, has shown strong efficacy against several cancers including ultraviolet radiation-induced skin (squamous) cancer; however, its potential activity against BCC is not yet examined. Herein, for the first time, we report the efficacy of silibinin and its oxidation product 2,3-dehydrosilibinin (DHS) against BCC both in vitro and in vivo using ASZ (p53 mutated) and BSZ (p53 deleted) cell lines derived from murine BCC tumors. Both silibinin and DHS significantly inhibited cell growth and clonogenicity while inducing apoptosis in a dose- and time-dependent manner, with DHS showing higher activity at lower concentrations. Both agents also inhibited the mitogenic signaling by reducing EGFR, ERK1/2, Akt, and STAT3 phosphorylation and suppressed the activation of transcription factors NF-κB and AP-1. More importantly, in an ectopic allograft model, oral administration of silibinin and DHS (200 mg/kg body weight) strongly inhibited the ASZ tumor growth by 44% and 71% (P < 0.05), respectively, and decreased the expression of proliferation biomarkers (PCNA and cyclin D1) as well as NF-κB p50 and c-Fos in the tumor tissues. Taken together, these results provide the first evidence for the efficacy and usefulness of silibinin and its derivative DHS against BCC, and suggest the need for additional studies with these agents in pre-clinical and clinical BCC chemoprevention and therapy models. © 2014 Wiley Periodicals, Inc.

  14. 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

    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.

  15. TDP2 suppresses chromosomal translocations induced by DNA topoisomerase II during gene transcription.

    Gómez-Herreros, Fernando; Zagnoli-Vieira, Guido; Ntai, Ioanna; Martínez-Macías, María Isabel; Anderson, Rhona M; Herrero-Ruíz, Andrés; Caldecott, Keith W

    2017-08-10

    DNA double-strand breaks (DSBs) induced by abortive topoisomerase II (TOP2) activity are a potential source of genome instability and chromosome translocation. TOP2-induced DNA double-strand breaks are rejoined in part by tyrosyl-DNA phosphodiesterase 2 (TDP2)-dependent non-homologous end-joining (NHEJ), but whether this process suppresses or promotes TOP2-induced translocations is unclear. Here, we show that TDP2 rejoins DSBs induced during transcription-dependent TOP2 activity in breast cancer cells and at the translocation 'hotspot', MLL. Moreover, we find that TDP2 suppresses chromosome rearrangements induced by TOP2 and reduces TOP2-induced chromosome translocations that arise during gene transcription. Interestingly, however, we implicate TDP2-dependent NHEJ in the formation of a rare subclass of translocations associated previously with therapy-related leukemia and characterized by junction sequences with 4-bp of perfect homology. Collectively, these data highlight the threat posed by TOP2-induced DSBs during transcription and demonstrate the importance of TDP2-dependent non-homologous end-joining in protecting both gene transcription and genome stability.DNA double-strand breaks (DSBs) induced by topoisomerase II (TOP2) are rejoined by TDP2-dependent non-homologous end-joining (NHEJ) but whether this promotes or suppresses translocations is not clear. Here the authors show that TDP2 suppresses chromosome translocations from DSBs introduced during gene transcription.

  16. Ubiquitin-specific peptidase 22 inhibits colon cancer cell invasion by suppressing the signal transducer and activator of transcription 3/matrix metalloproteinase 9 pathway.

    Ao, Ning; Liu, Yanyan; Bian, Xiaocui; Feng, Hailiang; Liu, Yuqin

    2015-08-01

    Colon cancer is associated with increased cell migration and invasion. In the present study, the role of ubiquitin-specific peptidase 22 (USP22) in signal transducer and activator of transcription 3 (STAT3)-mediated colon cancer cell invasion was investigated. The messenger RNA levels of STAT3 target genes were measured by reverse transcription-quantitative polymerase chain reaction, following USP22 knockdown by RNA interference in SW480 colon cancer cells. The matrix metalloproteinase 9 (MMP9) proteolytic activity and invasion potential of SW480 cells were measured by zymography and Transwell assay, respectively, following combined USP22 and STAT3 short interfering (si)RNA treatment or STAT3 siRNA treatment alone. Similarly, a cell counting kit-8 assay was used to detect the proliferation potential of SW480 cells. The protein expression levels of USP22, STAT3 and MMP9 were detected by immunohistochemistry in colon cancer tissue microarrays (TMAs) and the correlation between USP22, STAT3 and MMP9 was analyzed. USP22/STAT3 co-depletion partly rescued the MMP9 proteolytic activity and invasion of SW480 cells, compared with that of STAT3 depletion alone. However, the proliferation of USP22/STAT3si-SW480 cells was decreased compared with that of STAT3si-SW480 cells. USP22 expression was positively correlated with STAT3 and MMP9 expression in colon cancer TMAs. In conclusion, USP22 attenuated the invasion capacity of colon cancer cells by inhibiting the STAT3/MMP9 signaling pathway.

  17. TRIM45 negatively regulates NF-κB-mediated transcription and suppresses cell proliferation

    Shibata, Mio; Sato, Tomonobu; Nukiwa, Ryota; Ariga, Tadashi; Hatakeyama, Shigetsugu

    2012-01-01

    Highlights: ► NF-κB plays an important role in cell survival and carcinogenesis. ► TRIM45 negatively regulates TNFα-induced NF-κB-mediated transcription. ► TRIM45 overexpression suppresses cell growth. ► TRIM45 acts as a repressor for the NF-κB signal and regulates cell growth. -- Abstract: The NF-κB signaling pathway plays an important role in cell survival, immunity, inflammation, carcinogenesis, and organogenesis. Activation of NF-κB is regulated by several posttranslational modifications including phosphorylation, neddylation and ubiquitination. The NF-κB signaling pathway is activated by two distinct signaling mechanisms and is strictly modulated by the ubiquitin–proteasome system. It has been reported that overexpression of TRIM45, one of the TRIM family ubiquitin ligases, suppresses transcriptional activities of Elk-1 and AP-1, which are targets of the MAPK signaling pathway. In this study, we showed that TRIM45 also negatively regulates TNFα-induced NF-κB-mediated transcription by a luciferase reporter assay and that TRIM45 lacking a RING domain also has an activity to inhibit the NF-κB signal. Moreover, we found that TRIM45 overexpression suppresses cell growth. These findings suggest that TRIM45 acts as a repressor for the NF-κB signal and regulates cell growth.

  18. Rice homeobox transcription factor HOX1a positively regulates gibberellin responses by directly suppressing EL1.

    Wen, Bi-Qing; Xing, Mei-Qing; Zhang, Hua; Dai, Cheng; Xue, Hong-Wei

    2011-11-01

    Homeobox transcription factors are involved in various aspects of plant development, including maintenance of the biosynthesis and signaling pathways of different hormones. However, few direct targets of homeobox proteins have been identified. We here show that overexpression of rice homeobox gene HOX1a resulted in enhanced gibberellin (GA) response, indicating a positive effect of HOX1a in GA signaling. HOX1a is induced by GA and encodes a homeobox transcription factor with transcription repression activity. In addition, HOX1a suppresses the transcription of early flowering1 (EL1), a negative regulator of GA signaling, and further electrophoretic mobility shift assay and chromatin immunoprecipitation analysis revealed that HOX1a directly bound to the promoter region of EL1 to suppress its expression and stimulate GA signaling. These results demonstrate that HOX1a functions as a positive regulator of GA signaling by suppressing EL1, providing informative hints on the study of GA signaling. © 2011 Institute of Botany, Chinese Academy of Sciences.

  19. Suppression of HTLV-1 transcription by SIRT1 deacetylase

    Tang, HMV; Jin, D; Gao, W; Chan, CP; Iha, H; Yuen, KS

    2015-01-01

    Infection with HTLV-1 causes adult T-cell leukemia and tropical spastic paraparesis in different subsets of infected people. Treatments for HTLV-1-associated diseases are unspecific and unsatisfactory. Prophylactic measures have not been developed. Although HTLV-1 pathogenesis involves multiple stages and factors, high proviral load has been singled out as a major risk factor which predicts disease. HTLV-1 encodes Tax transactivator that potently activates transcription from viral long termin...

  20. TPL2 (Therapeutic Targeting Tumor Progression Locus-2)/ATF4 (Activating Transcription Factor-4)/SDF1α (Chemokine Stromal Cell-Derived Factor-α) Axis Suppresses Diabetic Retinopathy.

    Lai, De-Wei; Lin, Keng-Hung; Sheu, Wayne Huey-Herng; Lee, Maw-Rong; Chen, Chung-Yu; Lee, Wen-Jane; Hung, Yi-Wen; Shen, Chin-Chang; Chung, Tsung-Ju; Liu, Shing-Hwa; Sheu, Meei-Ling

    2017-09-01

    Diabetic retinopathy is characterized by vasopermeability, vascular leakage, inflammation, blood-retinal barrier breakdown, capillary degeneration, and neovascularization. However, the mechanisms underlying the association between diabetes mellitus and progression retinopathy remain unclear. TPL2 (tumor progression locus 2), a serine-threonine protein kinase, exerts a pathological effect on vascular angiogenesis. This study investigated the role of N ε -(carboxymethyl)lysine, a major advanced glycation end products, and the involved TPL2-related molecular signals in diabetic retinopathy using models of in vitro and in vivo and human samples. Serum N ε -(carboxymethyl)lysine levels and TPL2 kinase activity were significantly increased in clinical patients and experimental animals with diabetic retinopathy. Intravitreal administration of pharmacological blocker or neutralizing antibody inhibited TPL2 and effectively suppressed the pathological characteristics of retinopathy in streptozotocin-induced diabetic animal models. Intravitreal VEGF (vascular endothelial growth factor) neutralization also suppressed the diabetic retinopathy in diabetic animal models. Mechanistic studies in primary human umbilical vein endothelial cells and primary retinal microvascular endothelial cells from streptozotocin-diabetic rats, db/db mice, and samples from patients with diabetic retinopathy revealed a positive parallel correlation between N ε -(carboxymethyl)lysine and the TPL2/chemokine SDF1α (stromal cell-derived factor-α) axis that is dependent on endoplasmic reticulum stress-related molecules, especially ATF4 (activating transcription factor-4). This study demonstrates that inhibiting the N ε -(carboxymethyl)lysine-induced TPL2/ATF4/SDF1α axis can effectively prevent diabetes mellitus-mediated retinal microvascular dysfunction. This signaling axis may include the therapeutic potential for other diseases involving pathological neovascularization or macular edema. © 2017

  1. Acetylation-mediated suppression of transcription-independent memory: bidirectional modulation of memory by acetylation.

    Katja Merschbaecher

    Full Text Available Learning induced changes in protein acetylation, mediated by histone acetyl transferases (HATs, and the antagonistic histone deacetylases (HDACs play a critical role in memory formation. The status of histone acetylation affects the interaction between the transcription-complex and DNA and thus regulates transcription-dependent processes required for long-term memory (LTM. While the majority of studies report on the role of elevated acetylation in memory facilitation, we address the impact of both, increased and decreased acetylation on formation of appetitive olfactory memory in honeybees. We show that learning-induced changes in the acetylation of histone H3 at aminoacid-positions H3K9 and H3K18 exhibit distinct and different dynamics depending on the training strength. A strong training that induces LTM leads to an immediate increase in acetylation at H3K18 that stays elevated for hours. A weak training, not sufficient to trigger LTM, causes an initial increase in acetylation at H3K18, followed by a strong reduction in acetylation at H3K18 below the control group level. Acetylation at position H3K9 is not affected by associative conditioning, indicating specific learning-induced actions on the acetylation machinery. Elevating acetylation levels by blocking HDACs after conditioning leads to an improved memory. While memory after strong training is enhanced for at least 2 days, the enhancement after weak training is restricted to 1 day. Reducing acetylation levels by blocking HAT activity after strong training leads to a suppression of transcription-dependent LTM. The memory suppression is also observed in case of weak training, which does not require transcription processes. Thus, our findings demonstrate that acetylation-mediated processes act as bidirectional regulators of memory formation that facilitate or suppress memory independent of its transcription-requirement.

  2. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

    Wang, Xianwei; Lu, Jingjun; Khaidakov, Magomed; Mitra, Sona; Ding, Zufeng; Raina, Sameer; Goyal, Tanu; Mehta, Jawahar L.

    2012-01-01

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22 phox , p47 phox , p67 phox , NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H 2 O 2 . Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac fibroblast growth and collagen

  3. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

    Wang, Xianwei, E-mail: XWang2@UAMS.edu; Lu, Jingjun; Khaidakov, Magomed; Mitra, Sona; Ding, Zufeng; Raina, Sameer; Goyal, Tanu; Mehta, Jawahar L., E-mail: MehtaJL@UAMS.edu

    2012-03-15

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22{sup phox}, p47{sup phox}, p67{sup phox}, NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H{sub 2}O{sub 2}. Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac

  4. Suppression of Thyroid Hormone Receptor-Mediated Transcription ...

    TH)-induced TR-mediated transcription. We further examined the effects of methamidophos on TR-thyroid hormone response element (TRE) binding using the liquid chemiluminescent DNA pull-down assay (LCDPA), and found no dissociation of ...

  5. Promoter proximal polyadenylation sites reduce transcription activity

    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...

  6. SINE transcription by RNA polymerase III is suppressed by histone methylation but not by DNA methylation

    Varshney, Dhaval; Vavrova-Anderson, Jana; Oler, Andrew J.; Cowling, Victoria H.; Cairns, Bradley R.; White, Robert J.

    2015-01-01

    Short interspersed nuclear elements (SINEs), such as Alu, spread by retrotransposition, which requires their transcripts to be copied into DNA and then inserted into new chromosomal sites. This can lead to genetic damage through insertional mutagenesis and chromosomal rearrangements between non-allelic SINEs at distinct loci. SINE DNA is heavily methylated and this was thought to suppress its accessibility and transcription, thereby protecting against retrotransposition. Here we provide several lines of evidence that methylated SINE DNA is occupied by RNA polymerase III, including the use of high-throughput bisulphite sequencing of ChIP DNA. We find that loss of DNA methylation has little effect on accessibility of SINEs to transcription machinery or their expression in vivo. In contrast, a histone methyltransferase inhibitor selectively promotes SINE expression and occupancy by RNA polymerase III. The data suggest that methylation of histones rather than DNA plays a dominant role in suppressing SINE transcription. PMID:25798578

  7. Mitotic Transcriptional Activation: Clearance of Actively Engaged Pol II via Transcriptional Elongation Control in Mitosis.

    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.

  8. METHOD OF SUPPRESSING GASTROINTESTINAL UREASE ACTIVITY

    Visek, W.J.

    1963-04-23

    This patent shows a method of increasing the growth rate of chicks. Certain diacyl substituted ureas such as alloxan, murexide, and barbituric acid are added to their feed, thereby suppressing gastrointestinal urease activity and thus promoting growth. (AEC)

  9. Transcriptional Repressor HIC1 Contributes to Suppressive Function of Human Induced Regulatory T Cells

    Ubaid Ullah

    2018-02-01

    Full Text Available Regulatory T (Treg cells are critical in regulating the immune response. In vitro induced Treg (iTreg cells have significant potential in clinical medicine. However, applying iTreg cells as therapeutics is complicated by the poor stability of human iTreg cells and their variable suppressive activity. Therefore, it is important to understand the molecular mechanisms of human iTreg cell specification. We identified hypermethylated in cancer 1 (HIC1 as a transcription factor upregulated early during the differentiation of human iTreg cells. Although FOXP3 expression was unaffected, HIC1 deficiency led to a considerable loss of suppression by iTreg cells with a concomitant increase in the expression of effector T cell associated genes. SNPs linked to several immune-mediated disorders were enriched around HIC1 binding sites, and in vitro binding assays indicated that these SNPs may alter the binding of HIC1. Our results suggest that HIC1 is an important contributor to iTreg cell development and function.

  10. Low concentrations of bisphenol a suppress thyroid hormone receptor transcription through a nongenomic mechanism

    Sheng, Zhi-Guo [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Tang, Yuan [Department of Pharmaceutics, College of Pharmacy, Third Military Medical University, 30 Yanzheng Street, Chongqing 400038 (China); Liu, Yu-Xiang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Yuan, Ye; Zhao, Bao-Quan [Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850 (China); Chao, Xi-Juan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Zhu, Ben-Zhan, E-mail: bzhu@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)

    2012-02-15

    Bisphenol (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Various rodent and in vitro studies have shown that thyroid hormone (TH) function can be impaired by BPA. However, it is still unknown if low concentrations of BPA can suppress the thyroid hormone receptor (TR) transcription. The present study aims to investigate the possible suppressing effects of low concentrations of BPA on TR transcription and the involved mechanism(s) in CV-1 cells derived from cercopithecus aethiops monkey kidneys. Using gene reporter assays, BPA at concentrations as low as 10{sup −9} M suppresses TR or steroid receptor coactivator-1(SRC-1)-enhanced TR transcription, but not reducing TR/SRC-1 interaction in mammalian two-hybrid and glutathione S-transferase pull-down studies. It has been further shown that both nuclear receptor co-repressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) are recruited to the TR-β1 by BPA in the presence of physiologic concentrations of T3 or T4. However, the overexpression of β3 integrin or c-Src significantly reduces BPA-induced recruitment of N-CoR/SMRT to TR or suppression of TR transcription. Furthermore, BPA inhibits the T3/T4-mediated interassociation of the β3 integrin/c-Src/MAPK/TR-β1 pathways by the co-immunoprecipitation. These results indicate that low concentrations of BPA suppress the TR transcription by disrupting physiologic concentrations of T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways, followed by recruiting N-CoR/SMRT to TR-β1, providing a novel insight regarding the TH disruption effects of low concentration BPA. -- Highlights: ► Environmentally relevant concentrations of BPA suppress TR transcription. ► BPA recruits the N-CoR/SMRT to TR under the physiologic concentrations of T3/T4. ► BPA disrupts T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways.

  11. Low concentrations of bisphenol a suppress thyroid hormone receptor transcription through a nongenomic mechanism

    Sheng, Zhi-Guo; Tang, Yuan; Liu, Yu-Xiang; Yuan, Ye; Zhao, Bao-Quan; Chao, Xi-Juan; Zhu, Ben-Zhan

    2012-01-01

    Bisphenol (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Various rodent and in vitro studies have shown that thyroid hormone (TH) function can be impaired by BPA. However, it is still unknown if low concentrations of BPA can suppress the thyroid hormone receptor (TR) transcription. The present study aims to investigate the possible suppressing effects of low concentrations of BPA on TR transcription and the involved mechanism(s) in CV-1 cells derived from cercopithecus aethiops monkey kidneys. Using gene reporter assays, BPA at concentrations as low as 10 −9 M suppresses TR or steroid receptor coactivator-1(SRC-1)-enhanced TR transcription, but not reducing TR/SRC-1 interaction in mammalian two-hybrid and glutathione S-transferase pull-down studies. It has been further shown that both nuclear receptor co-repressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) are recruited to the TR-β1 by BPA in the presence of physiologic concentrations of T3 or T4. However, the overexpression of β3 integrin or c-Src significantly reduces BPA-induced recruitment of N-CoR/SMRT to TR or suppression of TR transcription. Furthermore, BPA inhibits the T3/T4-mediated interassociation of the β3 integrin/c-Src/MAPK/TR-β1 pathways by the co-immunoprecipitation. These results indicate that low concentrations of BPA suppress the TR transcription by disrupting physiologic concentrations of T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways, followed by recruiting N-CoR/SMRT to TR-β1, providing a novel insight regarding the TH disruption effects of low concentration BPA. -- Highlights: ► Environmentally relevant concentrations of BPA suppress TR transcription. ► BPA recruits the N-CoR/SMRT to TR under the physiologic concentrations of T3/T4. ► BPA disrupts T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways.

  12. Apple (Malus domestica) MdERF2 negatively affects ethylene biosynthesis during fruit ripening by suppressing MdACS1 transcription.

    Li, Tong; Jiang, Zhongyu; Zhang, Lichao; Tan, Dongmei; Wei, Yun; Yuan, Hui; Li, Tianlai; Wang, Aide

    2016-12-01

    Ripening in climacteric fruit requires the gaseous phytohormone ethylene. Although ethylene signaling has been well studied, knowledge of the transcriptional regulation of ethylene biosynthesis is still limited. Here we show that an apple (Malus domestica) ethylene response factor, MdERF2, negatively affects ethylene biosynthesis and fruit ripening by suppressing the transcription of MdACS1, a gene that is critical for biosynthesis of ripening-related ethylene. Expression of MdERF2 was suppressed by ethylene during ripening of apple fruit, and we observed that MdERF2 bound to the promoter of MdACS1 and directly suppressed its transcription. Moreover, MdERF2 suppressed the activity of the promoter of MdERF3, a transcription factor that we found to bind to the MdACS1 promoter, thereby increasing MdACS1 transcription. We determined that the MdERF2 and MdERF3 proteins directly interact, and this interaction suppresses the binding of MdERF3 to the MdACS1 promoter. Moreover, apple fruit with transiently downregulated MdERF2 expression showed higher ethylene production and faster ripening. Our results indicate that MdERF2 negatively affects ethylene biosynthesis and fruit ripening in apple by suppressing the transcription of MdACS1 via multiple mechanisms, thereby acting as an antagonist of positive ripening regulators. Our findings offer a deep understanding of the transcriptional regulation of ethylene biosynthesis during climacteric fruit ripening. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  13. Heterologous expression of gentian MYB1R transcription factors suppresses anthocyanin pigmentation in tobacco flowers.

    Nakatsuka, Takashi; Yamada, Eri; Saito, Misa; Fujita, Kohei; Nishihara, Masahiro

    2013-12-01

    Single-repeat MYB transcription factors, GtMYB1R1 and GtMYB1R9 , were isolated from gentian. Overexpression of these genes reduced anthocyanin accumulation in tobacco flowers, demonstrating their applicability to modification of flower color. RNA interference (RNAi) has recently been used to successfully modify flower color intensity in several plant species. In most floricultural plants, this technique requires prior isolation of target flavonoid biosynthetic genes from the same or closely related species. To overcome this limitation, we developed a simple and efficient method for reducing floral anthocyanin accumulation based on genetic engineering using novel transcription factor genes isolated from Japanese gentians. We identified two single-repeat MYB genes--GtMYB1R and GtMYB1R9--predominantly expressed in gentian petals. Transgenic tobacco plants expressing these genes were produced, and their flowers were analyzed for flavonoid components and expression of flavonoid biosynthetic genes. Transgenic tobacco plants expressing GtMYB1R1 or GtMYB1R9 exhibited significant reductions in floral anthocyanin accumulation, resulting in white-flowered phenotypes. Expression levels of chalcone isomerase (CHI), dihydroflavonol 4-reductase (DFR), and anthocyanidin synthase (ANS) genes were preferentially suppressed in these transgenic tobacco flowers. A yeast two-hybrid assay demonstrated that both GtMYB1R1 and GtMYB1R9 proteins interacted with the GtbHLH1 protein, previously identified as an anthocyanin biosynthesis regulator in gentian flowers. In addition, a transient expression assay indicated that activation of the gentian GtDFR promoter by the GtMYB3-GtbHLH1 complex was partly canceled by addition of GtMYB1R1 or GtMYB1R9. These results suggest that GtMYB1R1 and GtMYB1R9 act as antagonistic transcription factors of anthocyanin biosynthesis in gentian flowers. These genes should consequently be useful for manipulating anthocyanin accumulation via genetic engineering in

  14. The hydroxyflavone, fisetin, suppresses mast cell activation induced by interaction with activated T cell membranes

    Nagai, K; Takahashi, Y; Mikami, I; Fukusima, T; Oike, H; Kobori, M

    2009-01-01

    Background and purpose: Cell-to-cell interactions between mast cells and activated T cells are increasingly recognized as a possible mechanism in the aetiology of allergic or non-allergic inflammatory disorders. To determine the anti-allergic effect of fisetin, we examined the ability of fisetin to suppress activation of the human mast cell line, HMC-1, induced by activated Jurkat T cell membranes. Experimental approach: HMC-1 cells were incubated with or without fisetin for 15 min and then co-cultured with Jurkat T cell membranes activated by phorbol-12-myristate 13-acetate for 16 h. We determined gene expression in activated HMC-1 cells by DNA microarray and quantitative reverse transcription (RT)-PCR analysis. We also examined activation of the transcription factor NF-κB and MAP kinases (MAPKs) in activated HMC-1 cells. Key results: Fisetin suppresses cell spreading and gene expression in HMC-1 cells stimulated by activated T cell membranes. Additionally, we show that these stimulated HMC-1 cells expressed granzyme B. The stimulatory interaction also induced activation of NF-κB and MAPKs; these activations were suppressed by fisetin. Fisetin also reduced the amount of cell surface antigen CD40 and intercellular adhesion molecule-1 (ICAM-1) on activated HMC-1 cells. Conclusions and implications: Fisetin suppressed activation of HMC-1 cells by activated T cell membranes by interfering with cell-to-cell interaction and inhibiting the activity of NF-κB and MAPKs and thereby suppressing gene expression. Fisetin may protect against the progression of inflammatory diseases by limiting interactions between mast cells and activated T cells. PMID:19702784

  15. Albizia lebbeck suppresses histamine signaling by the inhibition of histamine H1 receptor and histidine decarboxylase gene transcriptions.

    Nurul, Islam Mohammed; Mizuguchi, Hiroyuki; Shahriar, Masum; Venkatesh, Pichairajan; Maeyama, Kazutaka; Mukherjee, Pulok K; Hattori, Masashi; Choudhuri, Mohamed Sahabuddin Kabir; Takeda, Noriaki; Fukui, Hiroyuki

    2011-11-01

    Histamine plays major roles in allergic diseases and its action is mediated mainly by histamine H(1) receptor (H1R). We have demonstrated that histamine signaling-related H1R and histidine decarboxylase (HDC) genes are allergic diseases sensitive genes and their expression level affects severity of the allergic symptoms. Therefore, compounds that suppress histamine signaling should be promising candidates as anti-allergic drugs. Here, we investigated the effect of the extract from the bark of Albizia lebbeck (AL), one of the ingredients of Ayruvedic medicines, on H1R and HDC gene expression using toluene-2,4-diisocyanate (TDI) sensitized allergy model rats and HeLa cells expressing endogenous H1R. Administration of the AL extract significantly decreased the numbers of sneezing and nasal rubbing. Pretreatment with the AL extract suppressed TDI-induced H1R and HDC mRNA elevations as well as [(3)H]mepyramine binding, HDC activity, and histamine content in the nasal mucosa. AL extract also suppressed TDI-induced up-regulation of IL-4, IL-5, and IL-13 mRNA. In HeLa cells, AL extract suppressed phorbol-12-myristate-13-acetate- or histamine-induced up-regulation of H1R mRNA. Our data suggest that AL alleviated nasal symptoms by inhibiting histamine signaling in TDI-sensitized rats through suppression of H1R and HDC gene transcriptions. Suppression of Th2-cytokine signaling by AL also suggests that it could affect the histamine-cytokine network. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Cyclin D3 interacts with human activating transcription factor 5 and potentiates its transcription activity

    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

  17. CSR-1 and P granules suppress sperm-specific transcription in the C. elegans germline.

    Campbell, Anne C; Updike, Dustin L

    2015-05-15

    Germ granules (P granules) in C. elegans are required for fertility and function to maintain germ cell identity and pluripotency. Sterility in the absence of P granules is often accompanied by the misexpression of soma-specific proteins and the initiation of somatic differentiation in germ cells. To investigate whether this is caused by the accumulation of somatic transcripts, we performed mRNA-seq on dissected germlines with and without P granules. Strikingly, we found that somatic transcripts do not increase in the young adult germline when P granules are impaired. Instead, we found that impairing P granules causes sperm-specific mRNAs to become highly overexpressed. This includes the accumulation of major sperm protein (MSP) transcripts in germ cells, a phenotype that is suppressed by feminization of the germline. A core component of P granules, the endo-siRNA-binding Argonaute protein CSR-1, has recently been ascribed with the ability to license transcripts for germline expression. However, impairing CSR-1 has very little effect on the accumulation of its mRNA targets. Instead, we found that CSR-1 functions with P granules to prevent MSP and sperm-specific mRNAs from being transcribed in the hermaphrodite germline. These findings suggest that P granules protect germline integrity through two different mechanisms, by (1) preventing the inappropriate expression of somatic proteins at the level of translational regulation, and by (2) functioning with CSR-1 to limit the domain of sperm-specific expression at the level of transcription. © 2015. Published by The Company of Biologists Ltd.

  18. Abscisic acid-dependent multisite phosphorylation regulates the activity of a transcription activator AREB1.

    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.

  19. Active vibration suppression of helicopter horizontal stabilizers

    Cinquemani, Simone; Cazzulani, Gabriele; Resta, Ferruccio

    2017-04-01

    Helicopters are among the most complex machines ever made. While ensuring high performance from the aeronautical point of view, they are not very comfortable due to vibration mainly created by the main rotor and by the interaction with the surrounding air. One of the most solicited structural elements of the vehicle are the horizontal stabilizers. These elements are particularly stressed because of their composite structure which, while guaranteeing lightness and strength, is characterized by a low damping. This work makes a preliminary analysis on the dynamics of the structure and proposes different solutions to actively suppress vibrations. Among them, the best in terms of the relationship between performance and weight / complexity of the system is that based on inertial actuators mounted on the inside of the horizontal stabilizers. The work addresses the issue of the design of the device and its use in the stabilizer from both the numerical and the experimental points of view.

  20. The strawberry FaMYB1 transcription factor suppresses anthocyanin and flavonol accumulation in transgenic tobacco.

    Aharoni, A; De Vos, C H; Wein, M; Sun, Z; Greco, R; Kroon, A; Mol, J N; O'Connell, A P

    2001-11-01

    Fruit ripening is characterized by dramatic changes in gene expression, enzymatic activities and metabolism. Although the process of ripening has been studied extensively, we still lack valuable information on how the numerous metabolic pathways are regulated and co-ordinated. In this paper we describe the characterization of FaMYB1, a ripening regulated strawberry gene member of the MYB family of transcription factors. Flowers of transgenic tobacco lines overexpressing FaMYB1 showed a severe reduction in pigmentation. A reduction in the level of cyanidin 3-rutinoside (an anthocyanin) and of quercetin-glycosides (flavonols) was observed. Expression of late flavonoid biosynthesis genes and their enzyme activities were adversely affected by FaMYB1 overexpression. Two-hybrid assays in yeast showed that FaMYB1 could interact with other known anthocyanin regulators, but it does not act as a transcriptional activator. Interestingly, the C-terminus of FaMYB1 contains the motif pdLNL(D)/(E)Lxi(G)/S. This motif is contained in a region recently proposed to be involved in the repression of transcription by AtMYB4, an Arabidopsis MYB protein. Our results suggest that FaMYB1 may play a key role in regulating the biosynthesis of anthocyanins and flavonols in strawberry. It may act to repress transcription in order to balance the levels of anthocyanin pigments produced at the latter stages of strawberry fruit maturation, and/or to regulate metabolite levels in various branches of the flavonoid biosynthetic pathway.

  1. Microbial enrichment to enhance the disease suppressive activity of compost

    Postma, J.; Montenari, M.; Boogert, van den P.H.J.F.

    2003-01-01

    Compost amended soil has been found to be suppressive against plant diseases in various cropping systems. The level and reproducibility of disease suppressive properties of compost might be increased by the addition of antagonists. In the present study, the establishment and suppressive activity of

  2. Assessing the Role of ETHYLENE RESPONSE FACTOR Transcriptional Repressors in Salicylic Acid-Mediated Suppression of Jasmonic Acid-Responsive Genes.

    Caarls, Lotte; Van der Does, Dieuwertje; Hickman, Richard; Jansen, Wouter; Verk, Marcel C Van; Proietti, Silvia; Lorenzo, Oscar; Solano, Roberto; Pieterse, Corné M J; Van Wees, Saskia C M

    2017-02-01

    Salicylic acid (SA) and jasmonic acid (JA) cross-communicate in the plant immune signaling network to finely regulate induced defenses. In Arabidopsis, SA antagonizes many JA-responsive genes, partly by targeting the ETHYLENE RESPONSE FACTOR (ERF)-type transcriptional activator ORA59. Members of the ERF transcription factor family typically bind to GCC-box motifs in the promoters of JA- and ethylene-responsive genes, thereby positively or negatively regulating their expression. The GCC-box motif is sufficient for SA-mediated suppression of JA-responsive gene expression. Here, we investigated whether SA-induced ERF-type transcriptional repressors, which may compete with JA-induced ERF-type activators for binding at the GCC-box, play a role in SA/JA antagonism. We selected ERFs that are transcriptionally induced by SA and/or possess an EAR transcriptional repressor motif. Several of the 16 ERFs tested suppressed JA-dependent gene expression, as revealed by enhanced JA-induced PDF1.2 or VSP2 expression levels in the corresponding erf mutants, while others were involved in activation of these genes. However, SA could antagonize JA-induced PDF1.2 or VSP2 in all erf mutants, suggesting that the tested ERF transcriptional repressors are not required for SA/JA cross-talk. Moreover, a mutant in the co-repressor TOPLESS, that showed reduction in repression of JA signaling, still displayed SA-mediated antagonism of PDF1.2 and VSP2. Collectively, these results suggest that SA-regulated ERF transcriptional repressors are not essential for antagonism of JA-responsive gene expression by SA. We further show that de novo SA-induced protein synthesis is required for suppression of JA-induced PDF1.2, pointing to SA-stimulated production of an as yet unknown protein that suppresses JA-induced transcription. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  3. Transcription elongation factor GreA has functional chaperone activity.

    Li, Kun; Jiang, Tianyi; Yu, Bo; Wang, Limin; Gao, Chao; Ma, Cuiqing; Xu, Ping; Ma, Yanhe

    2012-01-01

    Bacterial GreA is an indispensable factor in the RNA polymerase elongation complex. It plays multiple roles in transcriptional elongation, and may be implicated in resistance to various stresses. In this study, we show that Escherichia coli GreA inhibits aggregation of several substrate proteins under heat shock condition. GreA can also effectively promote the refolding of denatured proteins. These facts reveal that GreA has chaperone activity. Distinct from many molecular chaperones, GreA does not form stable complexes with unfolded substrates. GreA overexpression confers the host cells with enhanced resistance to heat shock and oxidative stress. Moreover, GreA expression in the greA/greB double mutant could suppress the temperature-sensitive phenotype, and dramatically alleviate the in vivo protein aggregation. The results suggest that bacterial GreA may act as chaperone in vivo. These results suggest that GreA, in addition to its function as a transcription factor, is involved in protection of cellular proteins against aggregation.

  4. The transcription factor EGR1 localizes to the nucleolus and is linked to suppression of ribosomal precursor synthesis.

    Ponti, Donatella; Bellenchi, Gian Carlo; Puca, Rosa; Bastianelli, Daniela; Maroder, Marella; Ragona, Giuseppe; Roussel, Pascal; Thiry, Marc; Mercola, Dan; Calogero, Antonella

    2014-01-01

    EGR1 is an immediate early gene with a wide range of activities as transcription factor, spanning from regulation of cell growth to differentiation. Numerous studies show that EGR1 either promotes the proliferation of stimulated cells or suppresses the tumorigenic growth of transformed cells. Upon interaction with ARF, EGR1 is sumoylated and acquires the ability to bind to specific targets such as PTEN and in turn to regulate cell growth. ARF is mainly localized to the periphery of nucleolus where is able to negatively regulate ribosome biogenesis. Since EGR1 colocalizes with ARF under IGF-1 stimulation we asked the question of whether EGR1 also relocate to the nucleolus to interact with ARF. Here we show that EGR1 colocalizes with nucleolar markers such as fibrillarin and B23 in the presence of ARF. Western analysis of nucleolar extracts from HeLa cells was used to confirm the presence of EGR1 in the nucleolus mainly as the 100 kDa sumoylated form. We also show that the level of the ribosomal RNA precursor 47S is inversely correlated to the level of EGR1 transcripts. The EGR1 iseffective to regulate the synthesis of the 47S rRNA precursor. Then we demonstrated that EGR1 binds to the Upstream Binding Factor (UBF) leading us to hypothesize that the regulating activity of EGR1 is mediated by its interaction within the transcriptional complex of RNA polymerase I. These results confirm the presence of EGR1 in the nucleolus and point to a role for EGR1 in the control of nucleolar metabolism.

  5. The transcription factor EGR1 localizes to the nucleolus and is linked to suppression of ribosomal precursor synthesis.

    Donatella Ponti

    Full Text Available EGR1 is an immediate early gene with a wide range of activities as transcription factor, spanning from regulation of cell growth to differentiation. Numerous studies show that EGR1 either promotes the proliferation of stimulated cells or suppresses the tumorigenic growth of transformed cells. Upon interaction with ARF, EGR1 is sumoylated and acquires the ability to bind to specific targets such as PTEN and in turn to regulate cell growth. ARF is mainly localized to the periphery of nucleolus where is able to negatively regulate ribosome biogenesis. Since EGR1 colocalizes with ARF under IGF-1 stimulation we asked the question of whether EGR1 also relocate to the nucleolus to interact with ARF. Here we show that EGR1 colocalizes with nucleolar markers such as fibrillarin and B23 in the presence of ARF. Western analysis of nucleolar extracts from HeLa cells was used to confirm the presence of EGR1 in the nucleolus mainly as the 100 kDa sumoylated form. We also show that the level of the ribosomal RNA precursor 47S is inversely correlated to the level of EGR1 transcripts. The EGR1 iseffective to regulate the synthesis of the 47S rRNA precursor. Then we demonstrated that EGR1 binds to the Upstream Binding Factor (UBF leading us to hypothesize that the regulating activity of EGR1 is mediated by its interaction within the transcriptional complex of RNA polymerase I. These results confirm the presence of EGR1 in the nucleolus and point to a role for EGR1 in the control of nucleolar metabolism.

  6. The transcriptional activator GAL4-VP16 regulates the intra ...

    Activator also reduced the TBP dimer levels both in vitro and in vivo, suggesting the dimer may be a direct target of transcriptional activators. The transcriptional activator facilitated the dimer to monomer transition and activated monomers further to help TBP bind even the weaker TATA boxes stably. The overall stimulatory ...

  7. Transcriptional activation of ribosomal RNA genes during compensatory renal hypertrophy

    Ouellette, A.J.; Moonka, R.; Zelenetz, A.; Malt, R.A.

    1986-01-01

    The overall rate of rDNA transcription increases by 50% during the first 24 hours of compensatory renal hypertrophy in the mouse. To study mechanisms of ribosome accumulation after uninephrectomy, transcription rates were measured in isolated kidneys by transcriptional runoff. 32 P-labeled nascent transcripts were hybridized to blots containing linearized, denatured cloned rDNA, and hybridization was quantitated autoradiographically and by direct counting. Overall transcriptional activity of rDNA was increased by 30% above control levels at 6 hrs after nephrectomy and by 50% at 12, 18, and 24 hrs after operation. Hybridizing RNA was insensitive to inhibiby alpha-amanitin, and no hybridization was detected to vector DNA. Thus, accelerated rDNA transcription is one regulatory element in the accretion of ribosomes in renal growth, and the regulatory event is an early event. Mechanisms of activation may include enhanced transcription of active genes or induction of inactive DNA

  8. RNAi trigger fragment truncation attenuates soybean FAD2-1 transcript suppression and yields intermediate oil phenotypes.

    Wagner, Nicholas; Mroczka, Andrew; Roberts, Peter D; Schreckengost, William; Voelker, Toni

    2011-09-01

    Suppression of the microsomal ω6 oleate desaturase during the seed development of soybean (Glycine max) with the 420-bp soybean FAD2-1A intron as RNAi trigger shifts the conventional fatty acid composition of soybean oil from 20% oleic and 60% polyunsaturates to one containing greater than 80% oleic acid and less than 10% polyunsaturates. To determine whether RNAi could be attenuated by reducing the trigger fragment length, transgenic plants were generated to express successively shorter 5' or 3' deletion derivatives of the FAD2-1A intron. We observed a gradual reduction in transcript suppression with shorter trigger fragments. Fatty acid composition was less affected with shorter triggers, and triggers less than 60 bp had no phenotypic effect. No trigger sequences conferring significantly higher or lower suppression efficiencies were found, and the primary determinant of suppression effect was sequence length. The observed relationship of transcript suppression with the induced fatty acid phenotype indicates that RNAi is a saturation process and not a step change between suppressed and nonsuppressed states and intermediate suppression states can be achieved. © 2010 Monsanto. Plant Biotechnology Journal © 2010 Society for Experimental Biology and Blackwell Publishing Ltd.

  9. Hypoxia-inducible factor (HIF)-1α and CCN2 form a regulatory circuit in hypoxic nucleus pulposus cells: CCN2 suppresses HIF-1α level and transcriptional activity.

    Tran, Cassie M; Fujita, Nobuyuki; Huang, Bau-Lin; Ong, Jessica R; Lyons, Karen M; Shapiro, Irving M; Risbud, Makarand V

    2013-05-03

    The objective of the study was to investigate if hypoxia-inducible factor (HIF)-1α and connective tissue growth factor (CCN2) form a regulatory network in hypoxic nucleus pulposus (NP) cells. A decrease in CCN2 expression and proximal promoter activity was observed in NP cells after hypoxic culture. Analysis of both human and mouse CCN2 promoters using the JASPAR core database revealed the presence of putative hypoxia response elements. Transfection experiments showed that both promoter activities and CCN2 expression decreases in hypoxia in a HIF-1α-dependent fashion. Interestingly, deletion analysis and mutation of the hypoxia responsive elements individually or in combination resulted in no change in promoter activity in response to hypoxia or in response to HIF-1α, suggesting an indirect mode of regulation. Notably, silencing of endogenous CCN2 increased HIF-1α levels and its target gene expression, suggesting a role for CCN2 in controlling basal HIF-1α levels. On the other hand, treatment of cells with rCCN2 resulted in a decrease in the ability of HIF-1α transactivating domain to recruit co-activators and diminished target gene expression. Last, knockdown of CCN2 in NP cells results in a significant decrease in GAG synthesis and expression of AGGRECAN and COLLAGEN II. Immunohistochemical staining of intervertebral discs of Ccn2 null embryos shows a decrease in aggrecan. These findings reveal a negative feedback loop between CCN2 and HIF-1α in NP cells and demonstrate a role for CCN2 in maintaining matrix homeostasis in this tissue.

  10. NF-κB Directly Regulates Fas Transcription to Modulate Fas-mediated Apoptosis and Tumor Suppression*

    Liu, Feiyan; Bardhan, Kankana; Yang, Dafeng; Thangaraju, Muthusamy; Ganapathy, Vadivel; Waller, Jennifer L.; Liles, Georgia B.; Lee, Jeffrey R.; Liu, Kebin

    2012-01-01

    Fas is a member of the death receptor family. Stimulation of Fas leads to induction of apoptotic signals, such as caspase 8 activation, as well as “non-apoptotic” cellular responses, notably NF-κB activation. Convincing experimental data have identified NF-κB as a critical promoter of cancer development, creating a solid rationale for the development of antitumor therapy that suppresses NF-κB activity. On the other hand, compelling data have also shown that NF-κB activity enhances tumor cell sensitivity to apoptosis and senescence. Furthermore, although stimulation of Fas activates NF-κB, the function of NF-κB in the Fas-mediated apoptosis pathway remains largely undefined. In this study, we observed that deficiency of either Fas or FasL resulted in significantly increased incidence of 3-methylcholanthrene-induced spontaneous sarcoma development in mice. Furthermore, Fas-deficient mice also exhibited significantly greater incidence of azoxymethane and dextran sodium sulfate-induced colon carcinoma. In addition, human colorectal cancer patients with high Fas protein in their tumor cells had a longer time before recurrence occurred. Engagement of Fas with FasL triggered NF-κB activation. Interestingly, canonical NF-κB was found to directly bind to the FAS promoter. Blocking canonical NF-κB activation diminished Fas expression, whereas blocking alternate NF-κB increased Fas expression in human carcinoma cells. Moreover, although canonical NF-κB protected mouse embryo fibroblast (MEF) cells from TNFα-induced apoptosis, knocking out p65 diminished Fas expression in MEF cells, resulting in inhibition of FasL-induced caspase 8 activation and apoptosis. In contrast, knocking out p52 increased Fas expression in MEF cells. Our observations suggest that canonical NF-κB is a Fas transcription activator and alternate NF-κB is a Fas transcription repressor, and Fas functions as a suppressor of spontaneous sarcoma and colon carcinoma. PMID:22669972

  11. Cyclin F suppresses B-Myb activity to promote cell cycle checkpoint control

    Klein, Ditte Kjærsgaard; Hoffmann, Saskia; Ahlskog, Johanna K

    2015-01-01

    an important role in checkpoint control following ionizing radiation. Cyclin F-depleted cells initiate checkpoint signalling after ionizing radiation, but fail to maintain G2 phase arrest and progress into mitosis prematurely. Importantly, cyclin F suppresses the B-Myb-driven transcriptional programme...... that promotes accumulation of crucial mitosis-promoting proteins. Cyclin F interacts with B-Myb via the cyclin box domain. This interaction is important to suppress cyclin A-mediated phosphorylation of B-Myb, a key step in B-Myb activation. In summary, we uncover a regulatory mechanism linking the F-box protein...

  12. Yeast Sub1 and human PC4 are G-quadruplex binding proteins that suppress genome instability at co-transcriptionally formed G4 DNA.

    Lopez, Christopher R; Singh, Shivani; Hambarde, Shashank; Griffin, Wezley C; Gao, Jun; Chib, Shubeena; Yu, Yang; Ira, Grzegorz; Raney, Kevin D; Kim, Nayun

    2017-06-02

    G-quadruplex or G4 DNA is a non-B secondary DNA structure consisting of a stacked array of guanine-quartets that can disrupt critical cellular functions such as replication and transcription. When sequences that can adopt Non-B structures including G4 DNA are located within actively transcribed genes, the reshaping of DNA topology necessary for transcription process stimulates secondary structure-formation thereby amplifying the potential for genome instability. Using a reporter assay designed to study G4-induced recombination in the context of an actively transcribed locus in Saccharomyces cerevisiae, we tested whether co-transcriptional activator Sub1, recently identified as a G4-binding factor, contributes to genome maintenance at G4-forming sequences. Our data indicate that, upon Sub1-disruption, genome instability linked to co-transcriptionally formed G4 DNA in Top1-deficient cells is significantly augmented and that its highly conserved DNA binding domain or the human homolog PC4 is sufficient to suppress G4-associated genome instability. We also show that Sub1 interacts specifically with co-transcriptionally formed G4 DNA in vivo and that yeast cells become highly sensitivity to G4-stabilizing chemical ligands by the loss of Sub1. Finally, we demonstrate the physical and genetic interaction of Sub1 with the G4-resolving helicase Pif1, suggesting a possible mechanism by which Sub1 suppresses instability at G4 DNA. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. The oncoprotein gankyrin interacts with RelA and suppresses NF-κB activity

    Higashitsuji, Hiroaki; Higashitsuji, Hisako; Liu, Yu; Masuda, Tomoko; Fujita, Takanori; Abdel-Aziz, H. Ismail; Kongkham, Supranee; Dawson, Simon; John Mayer, R.; Itoh, Yoshito; Sakurai, Toshiharu; Itoh, Katsuhiko; Fujita, Jun

    2007-01-01

    Gankyrin is an oncoprotein commonly overexpressed in hepatocellular carcinomas. It interacts with multiple proteins and accelerates degradation of tumor suppressors Rb and p53. Since gankyrin consists of 7 ankyrin repeats and is structurally similar to IκBs, we investigated its interaction with NF-κB. We found that gankyrin directly binds to RelA. In HeLa and 293 cells, overexpression of gankyrin suppressed the basal as well as TNFα-induced transcriptional activity of NF-κB, whereas down-regulation of gankyrin increased it. Gankyrin did not affect the NF-κB DNA-binding activity or nuclear translocation of RelA induced by TNFα in these cells. Leptomycin B that inhibits nuclear export of RelA suppressed the NF-κB activity, which was further suppressed by gankyrin. The inhibitory effect of gankyrin was abrogated by nicotinamide as well as down-regulation of SIRT1, a class III histone deacetylase. Thus, gankyrin binds to NF-κB and suppresses its activity at the transcription level by modulating acetylation via SIRT1

  14. Isoniazid suppresses antioxidant response element activities and impairs adipogenesis in mouse and human preadipocytes

    Chen, Yanyan; Xue, Peng; Hou, Yongyong; Zhang, Hao; Zheng, Hongzhi; Zhou, Tong; Qu, Weidong; Teng, Weiping; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

    2013-01-01

    Transcriptional signaling through the antioxidant response element (ARE), orchestrated by the Nuclear factor E2-related factor 2 (Nrf2), is a major cellular defense mechanism against oxidative or electrophilic stress. Here, we reported that isoniazid (INH), a widely used antitubercular drug, displays a substantial inhibitory property against ARE activities in diverse mouse and human cells. In 3T3-L1 preadipocytes, INH concentration-dependently suppressed the ARE-luciferase reporter activity and mRNA expression of various ARE-dependent antioxidant genes under basal and oxidative stressed conditions. In keeping with our previous findings that Nrf2-ARE plays a critical role in adipogenesis by regulating expression of CCAAT/enhancer-binding protein β (C/EBPβ) and peroxisome proliferator-activated receptor γ (PPARγ), suppression of ARE signaling by INH hampered adipogenic differentiation of 3T3-L1 cells and human adipose-derived stem cells (ADSCs). Following adipogenesis induced by hormonal cocktails, INH-treated 3T3-L1 cells and ADSCs displayed significantly reduced levels of lipid accumulation and attenuated expression of C/EBPα and PPARγ. Time-course studies in 3T3-L1 cells revealed that inhibition of adipogenesis by INH occurred in the early stage of terminal adipogenic differentiation, where reduced expression of C/EBPβ and C/EBPδ was observed. To our knowledge, the present study is the first to demonstrate that INH suppresses ARE signaling and interrupts with the transcriptional network of adipogenesis, leading to impaired adipogenic differentiation. The inhibition of ARE signaling may be a potential underlying mechanism by which INH attenuates cellular antioxidant response contributing to various complications. - Highlights: • Isoniazid suppresses ARE-mediated transcriptional activity. • Isoniazid inhibits adipogenesis in preadipocytes. • Isoniazid suppresses adipogenic gene expression during adipogenesis

  15. Chalepin: A Compound from Ruta angustifolia L. Pers Exhibits Cell Cycle Arrest at S phase, Suppresses Nuclear Factor-Kappa B (NF-κB) Pathway, Signal Transducer and Activation of Transcription 3 (STAT3) Phosphorylation and Extrinsic Apoptotic Pathway in Non-small Cell Lung Cancer Carcinoma (A549).

    Richardson, Jaime Stella Moses; Aminudin, Norhaniza; Abd Malek, Sri Nurestri

    2017-10-01

    Plants have been a major source of inspiration in developing novel drug compounds in the treatment of various diseases that afflict human beings worldwide. Ruta angustifolia L. Pers known locally as Garuda has been conventionally used for various medicinal purposes such as in the treatment of cancer. A dihydrofuranocoumarin named chalepin, which was isolated from the chloroform extract of the plant, was tested on its ability to inhibit molecular pathways of human lung carcinoma (A549) cells. Cell cycle analysis and caspase 8 activation were conducted using a flow cytometer, and protein expressions in molecular pathways were determined using Western blot technique. Cell cycle analysis showed that cell cycle was arrested at the S phase. Further studies using Western blotting technique showed that cell cycle-related proteins such as cyclins, cyclin-dependent kinases (CDKs), and inhibitors of CDKs correspond to a cell cycle arrest at the S phase. Chalepin also showed inhibition in the expression of inhibitors of apoptosis proteins. Nuclear factor-kappa B (NF-κB) pathway, signal transducer and activation of transcription 3 (STAT-3), cyclooxygenase-2, and c-myc were also downregulated upon treatment with chalepin. Chalepin was found to induce extrinsic apoptotic pathway. Death receptors 4 and 5 showed a dramatic upregulation at 24 h. Analysis of activation of caspase 8 with the flow cytometer showed an increase in activity in a dose- and time-dependent manner. Activation of caspase 8 induced cleavage of BH3-interacting domain death agonist, which initiated a mitochondrial-dependent or -independent apoptosis. Chalepin causes S phase cell cycle arrest, NF-κB pathway inhibition, and STAT-3 inhibition, induces extrinsic apoptotic pathway, and could be an excellent chemotherapeutic agent. This study reports the capacity of an isolated bioactive compound known as chalepin to suppress the nuclear factor kappa-light-chain-enhancer of activated B cells pathway, signal

  16. From DNA binding to transcriptional activation: Is the TALE complete?

    Bobola, Nicoletta

    2017-09-04

    How transcription factors (TFs) control enhancer and promoter functions to effect changes in gene expression is an important question. In this issue, Hau et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201701154) show that the TALE TF MEIS recruits the histone modifier PARP1/ARTD1 at promoters to decompact chromatin and activate transcription. © 2017 Bobola.

  17. Glycogen synthase kinase-3 inhibitors suppress the AR-V7-mediated transcription and selectively inhibit cell growth in AR-V7-positive prostate cancer cells.

    Nakata, Daisuke; Koyama, Ryokichi; Nakayama, Kazuhide; Kitazawa, Satoshi; Watanabe, Tatsuya; Hara, Takahito

    2017-06-01

    Recent evidence suggests that androgen receptor (AR) splice variants, including AR-V7, play a pivotal role in resistance to androgen blockade in prostate cancer treatment. The development of new therapeutic agents that can suppress the transcriptional activities of AR splice variants has been anticipated as the next generation treatment of castration-resistant prostate cancer. High-throughput screening of AR-V7 signaling inhibitors was performed using an AR-V7 reporter system. The effects of a glycogen synthase kinase-3 (GSK3) inhibitor, LY-2090314, on endogenous AR-V7 signaling were evaluated in an AR-V7-positive cell line, JDCaP-hr, by quantitative reverse transcription polymerase chain reaction. The relationship between AR-V7 signaling and β-catenin signaling was assessed using RNA interference. The effect of LY-2090314 on cell growth in various prostate cancer cell lines was also evaluated. We identified GSK3 inhibitors as transcriptional suppressors of AR-V7 using a high-throughput screen with an AR-V7 reporter system. LY-2090314 suppressed the reporter activity and endogenous AR-V7 activity in JDCaP-hr cells. Because silencing of β-catenin partly rescued the suppression, it was evident that the suppression was mediated, at least partially, via the activation of β-catenin signaling. AR-V7 signaling and β-catenin signaling reciprocally regulate each other in JDCaP-hr cells, and therefore, GSK3 inhibition can repress AR-V7 transcriptional activity by accumulating intracellular β-catenin. Notably, LY-2090314 selectively inhibited the growth of AR-V7-positive prostate cancer cells in vitro. Our findings demonstrate the potential of GSK3 inhibitors in treating advanced prostate cancer driven by AR splice variants. In vivo evaluation of AR splice variant-positive prostate cancer models will help illustrate the overall significance of GSK3 inhibitors in treating prostate cancer. © 2017 Wiley Periodicals, Inc.

  18. TRANSCRIPTIONAL INHIBITION OF INTERLEUKIN-12 PROMOTER ACTIVITY IN LEISHMANIA SPP.-INFECTED MACROPHAGES

    Jayakumar, Asha; Widenmaier, Robyn; Ma, Xiaojing; McDowell, Mary Ann

    2009-01-01

    To establish and persist within a host, Leishmania spp. parasites delay the onset of cell-mediated immunity by suppressing interleukin-12 (IL-12) production from host macrophages. Although it is established that Leishmania spp.-infected macrophages have impaired IL-12 production, the mechanisms that account for this suppression remain to be completely elucidated. Using a luciferase reporter assay assessing IL-12 transcription, we report here that Leishmania major, Leishmania donovani, and Leishmania chagasi inhibit IL-12 transcription in response to interferon-gamma, lipopolysaccharide, and CD40 ligand and that Leishmania spp. lipophosphoglycan, phosphoglycans, and major surface protein are not necessary for inhibition. In addition, all the Leishmania spp. strains and life-cycle stages tested inhibited IL-12 promoter activity. Our data further reveal that autocrine-acting host factors play no role in the inhibitory response and that phagocytosis signaling is necessary for inhibition of IL-12. PMID:18372625

  19. Cold suppresses agonist-induced activation of TRPV1.

    Chung, M-K; Wang, S

    2011-09-01

    Cold therapy is frequently used to reduce pain and edema following acute injury or surgery such as tooth extraction. However, the neurobiological mechanisms of cold therapy are not completely understood. Transient receptor potential vanilloid 1 (TRPV1) is a capsaicin- and heat-gated nociceptive ion channel implicated in thermosensation and pathological pain under conditions of inflammation or injury. Although capsaicin-induced nociception, neuropeptide release, and ionic currents are suppressed by cold, it is not known if cold suppresses agonist-induced activation of recombinant TRPV1. We demonstrate that cold strongly suppressed the activation of recombinant TRPV1 by multiple agonists and capsaicin-evoked currents in trigeminal ganglia neurons under normal and phosphorylated conditions. Cold-induced suppression was partially impaired in a TRPV1 mutant that lacked heat-mediated activation and potentiation. These results suggest that cold-induced suppression of TRPV1 may share a common molecular basis with heat-induced potentiation, and that allosteric inhibition may contribute, in part, to the cold-induced suppression. We also show that combination of cold and a specific antagonist of TRPV1 can produce an additive suppression. Our results provide a mechanistic basis for cold therapy and may enhance anti-nociceptive approaches that target TRPV1 for managing pain under inflammation and tissue injury, including that from tooth extraction.

  20. Engineering prokaryotic transcriptional activators as metabolite biosensors in yeast

    Skjødt, Mette Louise; Snoek, Tim; Kildegaard, Kanchana Rueksomtawin

    2016-01-01

    ,cis-muconic acid at different levels, and found that reporter gene output correlated with production. The transplantation of prokaryotic transcriptional activators into the eukaryotic chassis illustrates the potential of a hitherto untapped biosensor resource useful for biotechnological applications....... real-time monitoring of production has attracted attention. Here we applied systematic engineering of multiple parameters to search for a general biosensor design in the budding yeast Saccharomyces cerevisiae based on small-molecule binding transcriptional activators from the prokaryote superfamily...

  1. Memory suppression is an active process that improves over childhood

    Pedro M Paz-Alonso

    2009-09-01

    Full Text Available We all have memories that we prefer not to think about. The ability to suppress retrieval of unwanted memories has been documented in behavioral and neuroimaging research using the Think/No-Think (TNT paradigm with adults. Attempts to stop memory retrieval are associated with increased activation of lateral prefrontal cortex (PFC and concomitant reduced activation in medial temporal lobe (MTL structures. However, the extent to which children have the ability to actively suppress their memories is unknown. This study investigated memory suppression in middle childhood using the TNT paradigm. Forty children aged 8 to 12 and 30 young adults were instructed either to remember (Think or suppress (No-Think the memory of the second word of previously studied word-pairs, when presented with the first member as a reminder. They then performed two different cued recall tasks, testing their memory for the second word in each pair after the Think/No-Think phase using the same first studied word within the pair as a cue (intra-list cue and also an independent cue (extra-list cue. Children exhibited age-related improvements in memory suppression from age 8 to 12 in both memory tests, against a backdrop of overall improvements in declarative memory over this age range. These findings suggest that memory suppression is an active process that develops during late childhood, likely due to an age-related refinement in the ability to engage PFC to down-regulate activity in areas involved in episodic retrieval.

  2. Androgen-androgen receptor system improves chronic inflammatory conditions by suppressing monocyte chemoattractant protein-1 gene expression in adipocytes via transcriptional regulation

    Morooka, Nobukatsu, E-mail: amorooka@gunma-u.ac.jp [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan); Ueguri, Kei [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan); Yee, Karen Kar Lye [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan); Human Resources Cultivation Center, Gunma University, 1-5-1 Tenjin-cho, Kiryushi, Gunma, 376-8515 (Japan); Yanase, Toshihiko [Department of Endocrinology and Diabetes Mellitus, School of Medicine, Fukuoka University, Jonan-ku, Fukuoka, 814-0180 (Japan); Sato, Takashi [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan)

    2016-09-02

    Age-related decreases in sex hormones are closely related to chronic inflammation in obesity and metabolic diseases. Particularly, the molecular basis of androgen activity in regulating inflammation and controlling metabolism remains largely unknown. Obese adipocytes secrete monocyte chemoattractant protein-1 (MCP-1), a key chemokine that promotes the infiltration of monocytes/macrophages into adipose tissue, thereby leading to metabolic disorders. Here, we studied the role of androgen-androgen receptor (AR) action in regulating MCP-1 expression in adipose tissue. We observed the induction of Mcp-1 expression in 3T3-L1 adipocytes co-cultured with RAW264.7 macrophages. Additionally, Mcp-1 expression was upregulated by culturing in conditioned medium derived from inflammatory macrophages (M1-Mφ) containing tumor necrosis factor-alpha (TNF-α). We found that sex hormones downregulated TNF-α-induced Mcp-1 and interleukin (Il)-6 expression in 3T3-L1 adipocytes. Furthermore, luciferase-reporter analysis indicated that MCP-1 promoter activity was predominantly suppressed by dihydrotestosterone (DHT)-AR interactions through functional canonical nuclear factor-kappa B (NF-κB) sites, whereas non-canonical NF-κB site containing important flanking sequences exhibited minor contributions to DHT-AR transcriptional repression. These findings suggested that androgen-AR suppressed obesity-induced chronic inflammation in adipose tissue. - Highlights: • DHT, non-aromatizable androgen suppresses Mcp-1 expression in adipocytes. • Mcp-1 transcription was negatively regulated by DHT-AR action. • DHT-AR selectively regulates Mcp-1 transcription through distinct NF-κB sites.

  3. Androgen-androgen receptor system improves chronic inflammatory conditions by suppressing monocyte chemoattractant protein-1 gene expression in adipocytes via transcriptional regulation

    Morooka, Nobukatsu; Ueguri, Kei; Yee, Karen Kar Lye; Yanase, Toshihiko; Sato, Takashi

    2016-01-01

    Age-related decreases in sex hormones are closely related to chronic inflammation in obesity and metabolic diseases. Particularly, the molecular basis of androgen activity in regulating inflammation and controlling metabolism remains largely unknown. Obese adipocytes secrete monocyte chemoattractant protein-1 (MCP-1), a key chemokine that promotes the infiltration of monocytes/macrophages into adipose tissue, thereby leading to metabolic disorders. Here, we studied the role of androgen-androgen receptor (AR) action in regulating MCP-1 expression in adipose tissue. We observed the induction of Mcp-1 expression in 3T3-L1 adipocytes co-cultured with RAW264.7 macrophages. Additionally, Mcp-1 expression was upregulated by culturing in conditioned medium derived from inflammatory macrophages (M1-Mφ) containing tumor necrosis factor-alpha (TNF-α). We found that sex hormones downregulated TNF-α-induced Mcp-1 and interleukin (Il)-6 expression in 3T3-L1 adipocytes. Furthermore, luciferase-reporter analysis indicated that MCP-1 promoter activity was predominantly suppressed by dihydrotestosterone (DHT)-AR interactions through functional canonical nuclear factor-kappa B (NF-κB) sites, whereas non-canonical NF-κB site containing important flanking sequences exhibited minor contributions to DHT-AR transcriptional repression. These findings suggested that androgen-AR suppressed obesity-induced chronic inflammation in adipose tissue. - Highlights: • DHT, non-aromatizable androgen suppresses Mcp-1 expression in adipocytes. • Mcp-1 transcription was negatively regulated by DHT-AR action. • DHT-AR selectively regulates Mcp-1 transcription through distinct NF-κB sites.

  4. Peroxisome proliferator-activated receptor gamma recruits the positive transcription elongation factor b complex to activate transcription and promote adipogenesis

    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....

  5. PCAF Improves Glucose Homeostasis by Suppressing the Gluconeogenic Activity of PGC-1α

    Cheng Sun

    2014-12-01

    Full Text Available PGC-1α plays a central role in hepatic gluconeogenesis and has been implicated in the onset of type 2 diabetes. Acetylation is an important posttranslational modification for regulating the transcriptional activity of PGC-1α. Here, we show that PCAF is a pivotal acetyltransferase for acetylating PGC-1α in both fasted and diabetic states. PCAF acetylates two lysine residues K328 and K450 in PGC-1α, which subsequently triggers its proteasomal degradation and suppresses its transcriptional activity. Adenoviral-mediated expression of PCAF in the obese mouse liver greatly represses gluconeogenic enzyme activation and glucose production and improves glucose homeostasis and insulin sensitivity. Moreover, liver-specific knockdown of PCAF stimulates PGC-1α activity, resulting in an increase in blood glucose and hepatic glucose output. Our results suggest that PCAF might be a potential pharmacological target for developing agents against metabolic disorders associated with hyperglycemia, such as obesity and diabetes.

  6. Dataset of transcriptional landscape of B cell early activation

    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.

  7. Radiation activation of transcription factors in mammalian cells

    Kraemer, M.; Stein, B.; Mai, S.; Kunz, E.; Koenig, H.; Ponta, H.; Herrlich, P.; Rahmsdorf, H.J.; Loferer, H.; Grunicke, H.H.

    1990-01-01

    In mammalian cells radiation induces the enhanced transcription of several genes. The cis acting elements in the control region of inducible genes have been delimited by site directed mutagenesis. Several different elements have been found in different genes. They do not only activate gene transcription in response to radiation but also in response to growth factors and to tumor promoter phorbol esters. The transcription factors binding to these elements are present also in non-irradiated cells, but their DNA binding activity and their transactivating capability is increased upon irradiation. The signal chain linking the primary radiation induced signal (damaged DNA) to the activation of transcription factors involves the action of (a) protein kinase(s). (orig.)

  8. Detecting Differential Transcription Factor Activity from ATAC-Seq Data

    Ignacio J. Tripodi

    2018-05-01

    Full Text Available Transcription factors are managers of the cellular factory, and key components to many diseases. Many non-coding single nucleotide polymorphisms affect transcription factors, either by directly altering the protein or its functional activity at individual binding sites. Here we first briefly summarize high-throughput approaches to studying transcription factor activity. We then demonstrate, using published chromatin accessibility data (specifically ATAC-seq, that the genome-wide profile of TF recognition motifs relative to regions of open chromatin can determine the key transcription factor altered by a perturbation. Our method of determining which TFs are altered by a perturbation is simple, is quick to implement, and can be used when biological samples are limited. In the future, we envision that this method could be applied to determine which TFs show altered activity in response to a wide variety of drugs and diseases.

  9. Potential Role of Activating Transcription Factor 5 during Osteogenesis

    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.

  10. Potential Role of Activating Transcription Factor 5 during Osteogenesis.

    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.

  11. SIRT6-mediated transcriptional suppression of Txnip is critical for pancreatic beta cell function and survival in mice.

    Qin, Kunhua; Zhang, Ning; Zhang, Zhao; Nipper, Michael; Zhu, Zhenxin; Leighton, Jake; Xu, Kexin; Musi, Nicolas; Wang, Pei

    2018-04-01

    Better understanding of how genetic and epigenetic components control beta cell differentiation and function is key to the discovery of novel therapeutic approaches to prevent beta cell dysfunction and failure in the progression of type 2 diabetes. Our goal was to elucidate the role of histone deacetylase sirtuin 6 (SIRT6) in beta cell development and homeostasis. Sirt6 endocrine progenitor cell conditional knockout and beta cell-specific knockout mice were generated using the Cre-loxP system. Mice were assayed for islet morphology, glucose tolerance, glucose-stimulated insulin secretion and susceptibility to streptozotocin. Transcriptional regulatory functions of SIRT6 in primary islets were evaluated by RNA-Seq analysis. Reverse transcription-quantitative (RT-q)PCR and immunoblot were used to verify and investigate the gene expression changes. Chromatin occupancies of SIRT6, H3K9Ac, H3K56Ac and active RNA polymerase II were evaluated by chromatin immunoprecipitation. Deletion of Sirt6 in pancreatic endocrine progenitor cells did not affect endocrine morphology, beta cell mass or insulin production but did result in glucose intolerance and defective glucose-stimulated insulin secretion in mice. Conditional deletion of Sirt6 in adult beta cells reproduced the insulin secretion defect. Loss of Sirt6 resulted in aberrant upregulation of thioredoxin-interacting protein (TXNIP) in beta cells. SIRT6 deficiency led to increased acetylation of histone H3 lysine residue at 9 (H3K9Ac), acetylation of histone H3 lysine residue at 56 (H3K56Ac) and active RNA polymerase II at the promoter region of Txnip. SIRT6-deficient beta cells exhibited a time-dependent increase in H3K9Ac, H3K56Ac and TXNIP levels. Finally, beta cell-specific SIRT6-deficient mice showed increased sensitivity to streptozotocin. Our results reveal that SIRT6 suppresses Txnip expression in beta cells via deacetylation of histone H3 and plays a critical role in maintaining beta cell function and viability

  12. Fungal mediator tail subunits contain classical transcriptional activation domains.

    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.

  13. First Exon Length Controls Active Chromatin Signatures and Transcription

    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.

  14. Salicylic Acid Suppresses Jasmonic Acid Signaling Downstream of SCFCOI1-JAZ by Targeting GCC Promoter Motifs via Transcription Factor ORA59[C][W][OA

    Van der Does, Dieuwertje; Leon-Reyes, Antonio; Koornneef, Annemart; Van Verk, Marcel C.; Rodenburg, Nicole; Pauwels, Laurens; Goossens, Alain; Körbes, Ana P.; Memelink, Johan; Ritsema, Tita; Van Wees, Saskia C.M.; Pieterse, Corné M.J.

    2013-01-01

    Antagonism between the defense hormones salicylic acid (SA) and jasmonic acid (JA) plays a central role in the modulation of the plant immune signaling network, but the molecular mechanisms underlying this phenomenon are largely unknown. Here, we demonstrate that suppression of the JA pathway by SA functions downstream of the E3 ubiquitin-ligase Skip-Cullin-F-box complex SCFCOI1, which targets JASMONATE ZIM-domain transcriptional repressor proteins (JAZs) for proteasome-mediated degradation. In addition, neither the stability nor the JA-induced degradation of JAZs was affected by SA. In silico promoter analysis of the SA/JA crosstalk transcriptome revealed that the 1-kb promoter regions of JA-responsive genes that are suppressed by SA are significantly enriched in the JA-responsive GCC-box motifs. Using GCC:GUS lines carrying four copies of the GCC-box fused to the β-glucuronidase reporter gene, we showed that the GCC-box motif is sufficient for SA-mediated suppression of JA-responsive gene expression. Using plants overexpressing the GCC-box binding APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factors ERF1 or ORA59, we found that SA strongly reduces the accumulation of ORA59 but not that of ERF1. Collectively, these data indicate that the SA pathway inhibits JA signaling downstream of the SCFCOI1-JAZ complex by targeting GCC-box motifs in JA-responsive promoters via a negative effect on the transcriptional activator ORA59. PMID:23435661

  15. Salicylic acid suppresses jasmonic acid signaling downstream of SCFCOI1-JAZ by targeting GCC promoter motifs via transcription factor ORA59.

    Van der Does, Dieuwertje; Leon-Reyes, Antonio; Koornneef, Annemart; Van Verk, Marcel C; Rodenburg, Nicole; Pauwels, Laurens; Goossens, Alain; Körbes, Ana P; Memelink, Johan; Ritsema, Tita; Van Wees, Saskia C M; Pieterse, Corné M J

    2013-02-01

    Antagonism between the defense hormones salicylic acid (SA) and jasmonic acid (JA) plays a central role in the modulation of the plant immune signaling network, but the molecular mechanisms underlying this phenomenon are largely unknown. Here, we demonstrate that suppression of the JA pathway by SA functions downstream of the E3 ubiquitin-ligase Skip-Cullin-F-box complex SCF(COI1), which targets JASMONATE ZIM-domain transcriptional repressor proteins (JAZs) for proteasome-mediated degradation. In addition, neither the stability nor the JA-induced degradation of JAZs was affected by SA. In silico promoter analysis of the SA/JA crosstalk transcriptome revealed that the 1-kb promoter regions of JA-responsive genes that are suppressed by SA are significantly enriched in the JA-responsive GCC-box motifs. Using GCC:GUS lines carrying four copies of the GCC-box fused to the β-glucuronidase reporter gene, we showed that the GCC-box motif is sufficient for SA-mediated suppression of JA-responsive gene expression. Using plants overexpressing the GCC-box binding APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factors ERF1 or ORA59, we found that SA strongly reduces the accumulation of ORA59 but not that of ERF1. Collectively, these data indicate that the SA pathway inhibits JA signaling downstream of the SCF(COI1)-JAZ complex by targeting GCC-box motifs in JA-responsive promoters via a negative effect on the transcriptional activator ORA59.

  16. Salidroside Suppresses HUVECs Cell Injury Induced by Oxidative Stress through Activating the Nrf2 Signaling Pathway

    Yao Zhu

    2016-08-01

    Full Text Available Oxidative stress plays an important role in the pathogenesis of cardiovascular diseases. Salidroside (SAL, one of the main effective constituents of Rhodiola rosea, has been reported to suppress oxidative stress-induced cardiomyocyte injury and necrosis by promoting transcription of nuclear factor E2-related factor 2 (Nrf2-regulated genes such as heme oxygenase-1 (HO-1 and NAD(PH dehydrogenase (quinone1 (NQO1. However, it has not been indicated whether SAL might ameliorate endothelial injury induced by oxidative stress. Here, our study demonstrated that SAL might suppress HUVEC cell injury induced by oxidative stress through activating the Nrf2 signaling pathway. The results of our study indicated that SAL decreased the levels of intercellular reactive oxygen species (ROS and malondialdehyde (MDA, and improved the activities of superoxide dismutase (SOD and catalase (CAT, resulting in protective effects against oxidative stress-induced cell damage in HUVECs. It suppressed oxidative stress damage by inducing Nrf2 nuclear translocation and activating the expression of Nrf2-regulated antioxidant enzyme genes such as HO-1 and NQO1 in HUVECs. Knockdown of Nrf2 with siRNA abolished the cytoprotective effects against oxidative stress, decreased the expression of Nrf2, HO-1, and NQO1, and inhibited the nucleus translocation of Nrf2 in HUVECs. This study is the first to demonstrate that SAL suppresses HUVECs cell injury induced by oxidative stress through activating the Nrf2 signaling pathway.

  17. Deficiency of heat shock transcription factor 1 suppresses heat stress-associated increase in slow soleus muscle mass of mice.

    Ohno, Y; Egawa, T; Yokoyama, S; Nakai, A; Sugiura, T; Ohira, Y; Yoshioka, T; Goto, K

    2015-12-01

    Effects of heat shock transcription factor 1 (HSF1) deficiency on heat stress-associated increase in slow soleus muscle mass of mice were investigated. Both HSF1-null and wild-type mice were randomly assigned to control and heat-stressed groups. Mice in heat-stressed group were exposed to heat stress (41 °C for 60 min) in an incubator without anaesthesia. Significant increase in wet and dry weights, and protein content of soleus muscle in wild-type mice was observed seven days after the application of the heat stress. However, heat stress had no impact on soleus muscle mass in HSF1-null mice. Neither type of mice exhibited much effect of heat stress on HSF mRNA expression (HSF1, HSF2 and HSF4). On the other hand, heat stress upregulated heat shock proteins (HSPs) at the mRNA (HSP72) and protein (HSP72 and HSP110) levels in wild-type mice, but not in HSF1-null mice. The population of Pax7-positive nuclei relative to total myonuclei of soleus muscle in wild-type mice was significantly increased by heat stress, but not in HSF1-null mice. Furthermore, the absence of HSF1 gene suppressed heat stress-associated phosphorylation of Akt and p70 S6 kinase (p-p70S6K) in soleus muscle. Heat stress-associated increase in skeletal muscle mass may be induced by HSF1 and/or HSF1-mediated stress response that activates muscle satellite cells and Akt/p70S6K signalling pathway. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

  18. Cooperative activation of transcription by autoimmune regulator AIRE and CBP

    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

  19. Tip60 degradation by adenovirus relieves transcriptional repression of viral transcriptional activator EIA.

    Gupta, A; Jha, S; Engel, D A; Ornelles, D A; Dutta, A

    2013-10-17

    Adenoviruses are linear double-stranded DNA viruses that infect human and rodent cell lines, occasionally transform them and cause tumors in animal models. The host cell challenges the virus in multifaceted ways to restrain viral gene expression and DNA replication, and sometimes even eliminates the infected cells by programmed cell death. To combat these challenges, adenoviruses abrogate the cellular DNA damage response pathway. Tip60 is a lysine acetyltransferase that acetylates histones and other proteins to regulate gene expression, DNA damage response, apoptosis and cell cycle regulation. Tip60 is a bona fide tumor suppressor as mice that are haploid for Tip60 are predisposed to tumors. We have discovered that Tip60 is degraded by adenovirus oncoproteins EIB55K and E4orf6 by a proteasome-mediated pathway. Tip60 binds to the immediate early adenovirus promoter and suppresses adenovirus EIA gene expression, which is a master regulator of adenovirus transcription, at least partly through retention of the virally encoded repressor pVII on this promoter. Thus, degradation of Tip60 by the adenoviral early proteins is important for efficient viral early gene transcription and for changes in expression of cellular genes.

  20. Mastication suppresses initial gastric emptying by modulating gastric activity.

    Ohmure, H; Takada, H; Nagayama, K; Sakiyama, T; Tsubouchi, H; Miyawaki, S

    2012-03-01

    Because various mastication-related factors influence gastric activity, the functional relationship between mastication and gastric function has not been fully elucidated. To investigate the influence of mastication on gastric emptying and motility, we conducted a randomized trial to compare the effects of mastication on gastric emptying and gastric myoelectrical activity under conditions that excluded the influences of food comminution, taste, and olfaction. A (13)C-acetate breath test with electrogastrography and electrocardiography was performed in 14 healthy men who ingested a test meal with or without chewing gum. Autonomic nerve activity was evaluated by fluctuation analysis of heart rate. Gastric emptying was significantly delayed in the 'ingestion with mastication' group. Gastric myoelectrical activity was significantly suppressed during mastication and increased gradually in the post-mastication phase. A decrease in the high-frequency power of heart rate variability was observed coincidentally with gastric myoelectrical activity suppression. These findings suggest that initial gastric emptying is suppressed by mastication, and that the suppression is caused by mastication-induced inhibition of gastric activity (UMIN Clinical Trial Registration no. UMIN000005351).

  1. Transcriptional activity of transposable elements in coelacanth.

    Forconi, Mariko; Chalopin, Domitille; Barucca, Marco; Biscotti, Maria Assunta; De Moro, Gianluca; Galiana, Delphine; Gerdol, Marco; Pallavicini, Alberto; Canapa, Adriana; Olmo, Ettore; Volff, Jean-Nicolas

    2014-09-01

    The morphological stasis of coelacanths has long suggested a slow evolutionary rate. General genomic stasis might also imply a decrease of transposable elements activity. To evaluate the potential activity of transposable elements (TEs) in "living fossil" species, transcriptomic data of Latimeria chalumnae and its Indonesian congener Latimeria menadoensis were compared through the RNA-sequencing mapping procedures in three different organs (liver, testis, and muscle). The analysis of coelacanth transcriptomes highlights a significant percentage of transcribed TEs in both species. Major contributors are LINE retrotransposons, especially from the CR1 family. Furthermore, some particular elements such as a LF-SINE and a LINE2 sequences seem to be more expressed than other elements. The amount of TEs expressed in testis suggests possible transposition burst in incoming generations. Moreover, significant amount of TEs in liver and muscle transcriptomes were also observed. Analyses of elements displaying marked organ-specific expression gave us the opportunity to highlight exaptation cases, that is, the recruitment of TEs as new cellular genes, but also to identify a new Latimeria-specific family of Short Interspersed Nuclear Elements called CoeG-SINEs. Overall, transcriptome results do not seem to be in line with a slow-evolving genome with poor TE activity. © 2013 Wiley Periodicals, Inc.

  2. Sumoylation of the Plant Clock Transcription Factor CCA1 Suppresses DNA Binding

    Hansen, L.L.; Imrie, L.; Le Bihan, T.; van den Burg, H.A.; van Ooijen, G.

    2017-01-01

    In plants, the circadian clock regulates the expression of one-third of all transcripts and is crucial to virtually every aspect of metabolism and growth. We now establish sumoylation, a posttranslational protein modification, as a novel regulator of the key clock protein CCA1 in the model plant

  3. Exploring cellular memory molecules marking competent and active transcriptions

    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.

  4. Repressive effects of resveratrol on androgen receptor transcriptional activity.

    Wen-feng Shi

    2009-10-01

    Full Text Available The chemopreventive effects of resveratrol (RSV on prostate cancer have been well established; the androgen receptor (AR plays pivotal roles in prostatic tumorigenesis. However, the exact underlying molecular mechanisms about the effects of RSV on AR have not been fully elucidated. A model system is needed to determine whether and how RSV represses AR transcriptional activity.The AR cDNA was first cloned into the retroviral vector pOZ-N and then integrated into the genome of AR-negative HeLa cells to generate the AR(+ cells. The constitutively expressed AR was characterized by monitoring hormone-stimulated nuclear translocation, DNA binding, and transcriptional activation, with the AR(- cells serving as controls. AR(+ cells were treated with RSV, and both AR protein levels and AR transcriptional activity were measured simultaneously. Chromatin immunoprecipitation (ChIP assays were used to detect the effects of RSV on the recruitment of AR to its cognate element (ARE.AR in the AR (+ stable cell line functions in a manner similar to that of endogenously expressed AR. Using this model system we clearly demonstrated that RSV represses AR transcriptional activity independently of any effects on AR protein levels. However, neither the hormone-mediated nucleus translocation nor the AR/ARE interaction was affected by RSV treatment.We demonstrated unambiguously that RSV regulates AR target gene expression, at least in part, by repressing AR transcriptional activity. Repressive effects of RSV on AR activity result from mechanisms other than the affects of AR nuclear translocation or DNA binding.

  5. The transcriptionally active regions in the genome of Bacillus subtilis

    Rasmussen, Simon; Nielsen, Henrik Bjørn; Jarmer, Hanne Østergaard

    2009-01-01

    The majority of all genes have so far been identified and annotated systematically through in silico gene finding. Here we report the finding of 3662 strand-specific transcriptionally active regions (TARs) in the genome of Bacillus subtilis by the use of tiling arrays. We have measured the genome...

  6. Artifact suppression and analysis of brain activities with electroencephalography signals.

    Rashed-Al-Mahfuz, Md; Islam, Md Rabiul; Hirose, Keikichi; Molla, Md Khademul Islam

    2013-06-05

    Brain-computer interface is a communication system that connects the brain with computer (or other devices) but is not dependent on the normal output of the brain (i.e., peripheral nerve and muscle). Electro-oculogram is a dominant artifact which has a significant negative influence on further analysis of real electroencephalography data. This paper presented a data adaptive technique for artifact suppression and brain wave extraction from electroencephalography signals to detect regional brain activities. Empirical mode decomposition based adaptive thresholding approach was employed here to suppress the electro-oculogram artifact. Fractional Gaussian noise was used to determine the threshold level derived from the analysis data without any training. The purified electroencephalography signal was composed of the brain waves also called rhythmic components which represent the brain activities. The rhythmic components were extracted from each electroencephalography channel using adaptive wiener filter with the original scale. The regional brain activities were mapped on the basis of the spatial distribution of rhythmic components, and the results showed that different regions of the brain are activated in response to different stimuli. This research analyzed the activities of a single rhythmic component, alpha with respect to different motor imaginations. The experimental results showed that the proposed method is very efficient in artifact suppression and identifying individual motor imagery based on the activities of alpha component.

  7. SEPALLATA1/2-suppressed mature apples have low ethylene, high auxin and reduced transcription of ripening-related genes

    Schaffer, Robert J.; Ireland, Hilary S.; Ross, John J.; Ling, Toby J.; David, Karine M.

    2012-01-01

    Background and aims Fruit ripening is an important developmental trait in fleshy fruits, making the fruit palatable for seed dispersers. In some fruit species, there is a strong association between auxin concentrations and fruit ripening. We investigated the relationship between auxin concentrations and the onset of ethylene-related ripening in Malus × domestica (apples) at both the hormone and transcriptome levels. Methodology Transgenic apples suppressed for the SEPALLATA1/2 (SEP1/2) class of gene (MADS8/9) that showed severely reduced ripening were compared with untransformed control apples. In each apple type, free indole-3-acetic acid (IAA) concentrations were measured during early ripening. The changes observed in auxin were assessed in light of global changes in gene expression. Principal results It was found that mature MADS8/9-suppressed apples had a higher concentration of free IAA. This was associated with increased expression of the auxin biosynthetic genes in the indole-3-acetamide pathway. Additionally, in the MADS8/9-suppressed apples, there was less expression of the GH3 auxin-conjugating enzymes. A number of genes involved in the auxin-regulated transcription (AUX/IAA and ARF classes of genes) were also observed to change in expression, suggesting a mechanism for signal transduction at the start of ripening. Conclusions The delay in ripening observed in MADS8/9-suppressed apples may be partly due to high auxin concentrations. We propose that, to achieve low auxin associated with fruit maturation, the auxin homeostasis is controlled in a two-pronged manner: (i) by the reduction in biosynthesis and (ii) by an increase in auxin conjugation. This is associated with the change in expression of auxin-signalling genes and the up-regulation of ripening-related genes. PMID:23346344

  8. Active Suppression of Rotating Stall Inception with Distributed Jet Actuation

    Huu Duc Vo

    2007-01-01

    Full Text Available An analytical and experimental investigation of the effectiveness of full-span distributed jet actuation for active suppression of long length-scale rotating stall inception is carried out. Detailed modeling and experimental verification highlight the important effects of mass addition, discrete injectors, and feedback dynamics, which may be overlooked in preliminary theoretical studies of active control with jet injection. A model of the compression system incorporating nonideal injection and feedback dynamics is verified with forced response measurements to predict the right trends in the movement of the critical pole associated with the stall precursor. Active control experiments with proportional feedback control show that the predicted stall precursors are suppressed to give a 5.5% range extension in compressor flow coefficient. In addition, results suggest that the proposed model could be used to design a more sophisticated controller to further improve performance while reducing actuator bandwidth requirements.

  9. Hydrodynamic suppression of phase separation in active suspensions.

    Matas-Navarro, Ricard; Golestanian, Ramin; Liverpool, Tanniemola B; Fielding, Suzanne M

    2014-09-01

    We simulate with hydrodynamics a suspension of active disks squirming through a Newtonian fluid. We explore numerically the full range of squirmer area fractions from dilute to close packed and show that "motility induced phase separation," which was recently proposed to arise generically in active matter, and which has been seen in simulations of active Brownian disks, is strongly suppressed by hydrodynamic interactions. We give an argument for why this should be the case and support it with counterpart simulations of active Brownian disks in a parameter regime that provides a closer counterpart to hydrodynamic suspensions than in previous studies.

  10. Regulation of hepatitis B virus ENI enhancer activity by hepatocyte-enriched transcription factor HNF3.

    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.

  11. Transcription factor Amr1 induces melanin biosynthesis and suppresses virulence in Alternaria brassicicola.

    Yangrae Cho

    Full Text Available Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC were nonpathogenic and another gene (AbVf8 caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of Δamr1 and characterized their phenotypes. The Δamr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.

  12. Transcription Factor Amr1 Induces Melanin Biosynthesis and Suppresses Virulence in Alternaria brassicicola

    Cho, Yangrae; Srivastava, Akhil; Ohm, Robin A.; Lawrence, Christopher B.; Wang, Koon-Hui; Grigoriev, Igor V.; Marahatta, Sharadchandra P.

    2012-05-01

    Alternaria brassicicola is a successful saprophyte and necrotrophic plant pathogen. Several A. brassicicola genes have been characterized as affecting pathogenesis of Brassica species. To study regulatory mechanisms of pathogenesis, we mined 421 genes in silico encoding putative transcription factors in a machine-annotated, draft genome sequence of A. brassicicola. In this study, targeted gene disruption mutants for 117 of the transcription factor genes were produced and screened. Three of these genes were associated with pathogenesis. Disruption mutants of one gene (AbPacC) were nonpathogenic and another gene (AbVf8) caused lesions less than half the diameter of wild-type lesions. Unexpectedly, mutants of the third gene, Amr1, caused lesions with a two-fold larger diameter than the wild type and complementation mutants. Amr1 is a homolog of Cmr1, a transcription factor that regulates melanin biosynthesis in several fungi. We created gene deletion mutants of ?amr1 and characterized their phenotypes. The ?amr1 mutants used pectin as a carbon source more efficiently than the wild type, were melanin-deficient, and more sensitive to UV light and glucanase digestion. The AMR1 protein was localized in the nuclei of hyphae and in highly melanized conidia during the late stage of plant pathogenesis. RNA-seq analysis revealed that three genes in the melanin biosynthesis pathway, along with the deleted Amr1 gene, were expressed at low levels in the mutants. In contrast, many hydrolytic enzyme-coding genes were expressed at higher levels in the mutants than in the wild type during pathogenesis. The results of this study suggested that a gene important for survival in nature negatively affected virulence, probably by a less efficient use of plant cell-wall materials. We speculate that the functions of the Amr1 gene are important to the success of A. brassicicola as a competitive saprophyte and plant parasite.

  13. Suppression of a NAC-like transcription factor gene improves boron-toxicity tolerance in rice.

    Ochiai, Kumiko; Shimizu, Akifumi; Okumoto, Yutaka; Fujiwara, Toru; Matoh, Toru

    2011-07-01

    We identified a gene responsible for tolerance to boron (B) toxicity in rice (Oryza sativa), named BORON EXCESS TOLERANT1. Using recombinant inbred lines derived from the B-toxicity-sensitive indica-ecotype cultivar IR36 and the tolerant japonica-ecotype cultivar Nekken 1, the region responsible for tolerance to B toxicity was narrowed to 49 kb on chromosome 4. Eight genes are annotated in this region. The DNA sequence in this region was compared between the B-toxicity-sensitive japonica cultivar Wataribune and the B-toxicity-tolerant japonica cultivar Nipponbare by eco-TILLING analysis and revealed a one-base insertion mutation in the open reading frame sequence of the gene Os04g0477300. The gene encodes a NAC (NAM, ATAF, and CUC)-like transcription factor and the function of the transcript is abolished in B-toxicity-tolerant cultivars. Transgenic plants in which the expression of Os04g0477300 is abolished by RNA interference gain tolerance to B toxicity.

  14. FATS is a transcriptional target of p53 and associated with antitumor activity

    Zhang Xifeng

    2010-09-01

    Full Text Available Abstract Frequent mutations of p53 in human cancers exemplify its crucial role as a tumor suppressor transcription factor, and p21, a transcriptional target of p53, plays a central role in surveillance of cell-cycle checkpoints. Our previous study has shown that FATS stabilize p21 to preserve genome integrity. In this study we identified a novel transcript variant of FATS (GenBank: GQ499374 through screening a cDNA library from mouse testis, which uncovered the promoter region of mouse FATS. Mouse FATS was highly expressed in testis. The p53-responsive elements existed in proximal region of both mouse and human FATS promoters. Functional study indicated that the transcription of FATS gene was activated by p53, whereas such effect was abolished by site-directed mutagenesis in the p53-RE of FATS promoter. Furthermore, the expression of FATS increased upon DNA damage in a p53-dependent manner. FATS expression was silent or downregulated in human cancers, and overexpression of FATS suppressed tumorigenicity in vivo independently of p53. Our results reveal FATS as a p53-regulated gene to monitor genomic stability.

  15. Kefiran suppresses antigen-induced mast cell activation.

    Furuno, Tadahide; Nakanishi, Mamoru

    2012-01-01

    Kefir is a traditional fermented milk beverage produced by kefir grains in the Caucasian countries. Kefiran produced by Lactobacillus kefiranofaciens in kefir grains is an exopolysaccharide having a repeating structure with glucose and galactose residues in the chain sequence and has been suggested to exert many health-promoting effects such as immunomodulatory, hypotensive, hypocholesterolemic activities. Here we investigated the effects of kefiran on mast cell activation induced by antigen. Pretreatment with kefiran significantly inhibited antigen-induced Ca(2+) mobilization, degranulation, and tumor necrosis factor-α production in bone marrow-derived mast cells (BMMCs) in a dose-dependent manner. The phosphorylation of Akt, glycogen synthase kinase 3β, and extracellular signal-regulated kinases (ERKs) after antigen stimulation was also suppressed by pretreatment of BMMCs with kefiran. These findings indicate that kefiran suppresses mast cell degranulation and cytokine production by inhibiting the Akt and ERKs pathways, suggesting an anti-inflammatory effect for kefiran.

  16. Adaptive Active Noise Suppression Using Multiple Model Switching Strategy

    Quanzhen Huang

    2017-01-01

    Full Text Available Active noise suppression for applications where the system response varies with time is a difficult problem. The computation burden for the existing control algorithms with online identification is heavy and easy to cause control system instability. A new active noise control algorithm is proposed in this paper by employing multiple model switching strategy for secondary path varying. The computation is significantly reduced. Firstly, a noise control system modeling method is proposed for duct-like applications. Then a multiple model adaptive control algorithm is proposed with a new multiple model switching strategy based on filter-u least mean square (FULMS algorithm. Finally, the proposed algorithm was implemented on Texas Instruments digital signal processor (DSP TMS320F28335 and real time experiments were done to test the proposed algorithm and FULMS algorithm with online identification. Experimental verification tests show that the proposed algorithm is effective with good noise suppression performance.

  17. Oncogenes Activate an Autonomous Transcriptional Regulatory Circuit That Drives Glioblastoma

    Dinesh K. Singh

    2017-01-01

    Full Text Available Efforts to identify and target glioblastoma (GBM drivers have primarily focused on receptor tyrosine kinases (RTKs. Clinical benefits, however, have been elusive. Here, we identify an SRY-related box 2 (SOX2 transcriptional regulatory network that is independent of upstream RTKs and capable of driving glioma-initiating cells. We identified oligodendrocyte lineage transcription factor 2 (OLIG2 and zinc-finger E-box binding homeobox 1 (ZEB1, which are frequently co-expressed irrespective of driver mutations, as potential SOX2 targets. In murine glioma models, we show that different combinations of tumor suppressor and oncogene mutations can activate Sox2, Olig2, and Zeb1 expression. We demonstrate that ectopic co-expression of the three transcription factors can transform tumor-suppressor-deficient astrocytes into glioma-initiating cells in the absence of an upstream RTK oncogene. Finally, we demonstrate that the transcriptional inhibitor mithramycin downregulates SOX2 and its target genes, resulting in markedly reduced proliferation of GBM cells in vivo.

  18. Suppressed Expression of T-Box Transcription Factors is Involved in Senescence in Chronic Obstructive Pulmonary Disease

    Acquaah-Mensah, George; Malhotra, Deepti; Vulimiri, Madhulika; McDermott, Jason E.; Biswal, Shyam

    2012-06-19

    Chronic obstructive pulmonary disease (COPD) is a major global health problem. The etiology of COPD has been associated with apoptosis, oxidative stress, and inflammation. However, understanding of the molecular interactions that modulate COPD pathogenesis remains only partly resolved. We conducted an exploratory study on COPD etiology to identify the key molecular participants. We used information-theoretic algorithms including Context Likelihood of Relatedness (CLR), Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNE), and Inferelator. We captured direct functional associations among genes, given a compendium of gene expression profiles of human lung epithelial cells. A set of genes differentially expressed in COPD, as reported in a previous study were superposed with the resulting transcriptional regulatory networks. After factoring in the properties of the networks, an established COPD susceptibility locus and domain-domain interactions involving protein products of genes in the generated networks, several molecular candidates were predicted to be involved in the etiology of COPD. These include COL4A3, CFLAR, GULP1, PDCD1, CASP10, PAX3, BOK, HSPD1, PITX2, and PML. Furthermore, T-box (TBX) genes and cyclin-dependent kinase inhibitor 2A (CDKN2A), which are in a direct transcriptional regulatory relationship, emerged as preeminent participants in the etiology of COPD by means of senescence. Contrary to observations in neoplasms, our study reveals that the expression of genes and proteins in the lung samples from patients with COPD indicate an increased tendency towards cellular senescence. The expression of the anti-senescence mediators TBX transcription factors, chromatin modifiers histone deacetylases, and sirtuins was suppressed; while the expression of TBX-regulated cellular senescence markers such as CDKN2A, CDKN1A, and CAV1 was elevated in the peripheral lung tissue samples from patients with COPD. The critical balance between senescence

  19. The effect of phenobarbital on the transcriptional activity of liver.

    Hardwick, J P; Schwalm, F; Richardson, A

    1983-01-01

    The effect of phenobarbital on the transcriptional activity of liver was studied by measuring the synthesis of RNA by suspensions of hepatocytes isolated from rats treated with phenobarbital for various time periods. The absolute rates of RNA synthesis by isolated hepatocytes were determined by measuring the incorporation of [3H]orotic acid into RNA as UMP and the specific radioactivity of the UTP pool. The specific radioactivity of the UTP extracted from hepatocytes isolated from phenobarbit...

  20. Global RNA association with the transcriptionally active chromosome of chloroplasts.

    Lehniger, Marie-Kristin; Finster, Sabrina; Melonek, Joanna; Oetke, Svenja; Krupinska, Karin; Schmitz-Linneweber, Christian

    2017-10-01

    Processed chloroplast RNAs are co-enriched with preparations of the chloroplast transcriptionally active chromosome. Chloroplast genomes are organized as a polyploid DNA-protein structure called the nucleoid. Transcriptionally active chloroplast DNA together with tightly bound protein factors can be purified by gel filtration as a functional entity called the transcriptionally active chromosome (TAC). Previous proteomics analyses of nucleoids and of TACs demonstrated a considerable overlap in protein composition including RNA binding proteins. Therefore the RNA content of TAC preparations from Nicotiana tabacum was determined using whole genome tiling arrays. A large number of chloroplast RNAs was found to be associated with the TAC. The pattern of RNAs attached to the TAC consists of RNAs produced by different chloroplast RNA polymerases and differs from the pattern of RNA found in input controls. An analysis of RNA splicing and RNA editing of selected RNA species demonstrated that TAC-associated RNAs are processed to a similar extent as the RNA in input controls. Thus, TAC fractions contain a specific subset of the processed chloroplast transcriptome.

  1. Global suppression of electrocortical activity in unilateral perinatal thalamic stroke.

    Kharoshankaya, Liudmila

    2014-07-01

    We present an unusual case of persistent generalized electroencephalography (EEG) suppression and right-sided clonic seizures in a male infant born at 40(+2) weeks\\' gestation, birthweight 3240g, with an isolated unilateral thalamic stroke. The EEG at 13 hours after birth showed a generalized very low amplitude background pattern, which progressed to frequent electrographic seizures over the left hemisphere. The interictal background EEG pattern remained grossly abnormal over the next 48 hours, showing very low background amplitudes (<10μV). Magnetic resonance imaging revealed an isolated acute left-sided thalamic infarction. This is the first description of severe global EEG suppression caused by an isolated unilateral thalamic stroke and supports the role of the thalamus as the control centre for cortical electrical activity.

  2. Zipper plot: visualizing transcriptional activity of genomic regions.

    Avila Cobos, Francisco; Anckaert, Jasper; Volders, Pieter-Jan; Everaert, Celine; Rombaut, Dries; Vandesompele, Jo; De Preter, Katleen; Mestdagh, Pieter

    2017-05-02

    Reconstructing transcript models from RNA-sequencing (RNA-seq) data and establishing these as independent transcriptional units can be a challenging task. Current state-of-the-art tools for long non-coding RNA (lncRNA) annotation are mainly based on evolutionary constraints, which may result in false negatives due to the overall limited conservation of lncRNAs. To tackle this problem we have developed the Zipper plot, a novel visualization and analysis method that enables users to simultaneously interrogate thousands of human putative transcription start sites (TSSs) in relation to various features that are indicative for transcriptional activity. These include publicly available CAGE-sequencing, ChIP-sequencing and DNase-sequencing datasets. Our method only requires three tab-separated fields (chromosome, genomic coordinate of the TSS and strand) as input and generates a report that includes a detailed summary table, a Zipper plot and several statistics derived from this plot. Using the Zipper plot, we found evidence of transcription for a set of well-characterized lncRNAs and observed that fewer mono-exonic lncRNAs have CAGE peaks overlapping with their TSSs compared to multi-exonic lncRNAs. Using publicly available RNA-seq data, we found more than one hundred cases where junction reads connected protein-coding gene exons with a downstream mono-exonic lncRNA, revealing the need for a careful evaluation of lncRNA 5'-boundaries. Our method is implemented using the statistical programming language R and is freely available as a webtool.

  3. Global transcriptional regulatory network for Escherichia coli robustly connects gene expression to transcription factor activities

    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

  4. Kaposi's sarcoma-associated herpesvirus-encoded LANA associates with glucocorticoid receptor and enhances its transcriptional activities

    Togi, Sumihito; Nakasuji, Misa; Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Kitai, Yuichi; Kon, Shigeyuki; Oritani, Kenji; Matsuda, Tadashi

    2015-01-01

    Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA), which interacts with cellular proteins, plays a central role in modification of viral and/or cellular gene expression. Here, we show that LANA associates with glucocorticoid receptor (GR), and that LANA enhances the transcriptional activity of GR. Co-immunoprecipitation revealed a physical interaction between LANA and GR in transiently transfected 293T and HeLa cells. In human B-lymphoma cells, LANA overexpression enhanced GR activity and cell growth suppression following glucocorticoid stimulation. Furthermore, confocal microscopy showed that activated GR was bound to LANA and accumulated in the nucleus, leading to an increase in binding of activated GR to the glucocorticoid response element of target genes. Taken together, KSHV-derived LANA acts as a transcriptional co-activator of GR. Our results might suggest a careful use of glucocorticoids in the treatment of patients with KSHV-related malignancies such as Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. - Highlights: • KSHV-LANA enhances the transcriptional activity of GR in 293T and HeLa cells. • KSHV-LANA physically associates with GR. • KSHV-LANA enhances GR activation and cell growth suppression in human B-lymphocytes. • KSHV-LANA influences the nuclear retention and DNA binding activity of GR

  5. Kaposi's sarcoma-associated herpesvirus-encoded LANA associates with glucocorticoid receptor and enhances its transcriptional activities

    Togi, Sumihito; Nakasuji, Misa; Muromoto, Ryuta; Ikeda, Osamu; Okabe, Kanako; Kitai, Yuichi; Kon, Shigeyuki [Department of Immunology, Graduate School of Pharmaceutical Sciences Hokkaido University, Sapporo 060-0812 (Japan); Oritani, Kenji [Department of Hematology and Oncology, Graduate School of Medicine, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Matsuda, Tadashi, E-mail: tmatsuda@pharm.hokudai.ac.jp [Department of Immunology, Graduate School of Pharmaceutical Sciences Hokkaido University, Sapporo 060-0812 (Japan)

    2015-07-31

    Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA), which interacts with cellular proteins, plays a central role in modification of viral and/or cellular gene expression. Here, we show that LANA associates with glucocorticoid receptor (GR), and that LANA enhances the transcriptional activity of GR. Co-immunoprecipitation revealed a physical interaction between LANA and GR in transiently transfected 293T and HeLa cells. In human B-lymphoma cells, LANA overexpression enhanced GR activity and cell growth suppression following glucocorticoid stimulation. Furthermore, confocal microscopy showed that activated GR was bound to LANA and accumulated in the nucleus, leading to an increase in binding of activated GR to the glucocorticoid response element of target genes. Taken together, KSHV-derived LANA acts as a transcriptional co-activator of GR. Our results might suggest a careful use of glucocorticoids in the treatment of patients with KSHV-related malignancies such as Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman disease. - Highlights: • KSHV-LANA enhances the transcriptional activity of GR in 293T and HeLa cells. • KSHV-LANA physically associates with GR. • KSHV-LANA enhances GR activation and cell growth suppression in human B-lymphocytes. • KSHV-LANA influences the nuclear retention and DNA binding activity of GR.

  6. Suppressing cAMP response element-binding protein transcription shortens the duration of status epilepticus and decreases the number of spontaneous seizures in the pilocarpine model of epilepsy.

    Zhu, Xinjian; Dubey, Deepti; Bermudez, Camilo; Porter, Brenda E

    2015-12-01

    Current epilepsy therapies directed at altering the function of neurotransmitter receptors or ion channels, or release of synaptic vesicles fail to prevent seizures in approximately 30% of patients. A better understanding of the molecular mechanism underlying epilepsy is needed to provide new therapeutic targets. The activity of cyclic AMP (cAMP) response element-binding protein (CREB), a major transcription factor promoting CRE-mediated transcription, increases following a prolonged seizure called status epilepticus. It is also increased in the seizure focus of patients with medically intractable focal epilepsy. Herein we explored the effect of acute suppression of CREB activity on status epilepticus and spontaneous seizures in a chronic epilepsy model. Pilocarpine chemoconvulsant was used to induce status epilepticus. To suppress CREB activity, a transgenic mouse line expressing an inducible dominant negative mutant of CREB (CREB(IR) ) with a serine to alanine 133 substitution was used. Status epilepticus and spontaneous seizures of transgenic and wild-type mice were analyzed using video-electroencephalography (EEG) to assess the effect of CREB suppression on seizures. Our findings indicate that activation of CREB(IR) shortens the duration of status epilepticus. The frequency of spontaneous seizures decreased in mice with chronic epilepsy during CREB(IR) induction; however, the duration of the spontaneous seizures was unchanged. Of interest, we found significantly reduced levels of phospho-CREB Ser133 upon activation of CREB(IR) , supporting prior work suggesting that binding to the CRE site is important for CREB phosphorylation. Our results suggest that CRE transcription supports seizure activity both during status epilepticus and in spontaneous seizures. Thus, blocking of CRE transcription is a novel target for the treatment of epilepsy. Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.

  7. Meta-analysis of studies using suppression subtractive hybridization and microarrays to investigate the effects of environmental stress on gene transcription in oysters.

    Anderson, Kelli; Taylor, Daisy A; Thompson, Emma L; Melwani, Aroon R; Nair, Sham V; Raftos, David A

    2015-01-01

    Many microarray and suppression subtractive hybridization (SSH) studies have analyzed the effects of environmental stress on gene transcription in marine species. However, there have been no unifying analyses of these data to identify common stress response pathways. To address this shortfall, we conducted a meta-analysis of 14 studies that investigated the effects of different environmental stressors on gene expression in oysters. The stressors tested included chemical contamination, hypoxia and infection, as well as extremes of temperature, pH and turbidity. We found that the expression of over 400 genes in a range of oyster species changed significantly after exposure to environmental stress. A repeating pattern was evident in these transcriptional responses, regardless of the type of stress applied. Many of the genes that responded to environmental stress encoded proteins involved in translation and protein processing (including molecular chaperones), the mitochondrial electron transport chain, anti-oxidant activity and the cytoskeleton. In light of these findings, we put forward a consensus model of sub-cellular stress responses in oysters.

  8. Apparent suppression of MMP-9 activity by GD1a as determined by gelatin zymography.

    Hu, Dan; Tan, Xuan; Sato, Toshinori; Yamagata, Sadako; Yamagata, Tatsuya

    2006-10-13

    Gelatin zymography is widely used to detect and evaluate matrix metalloproteinase-9 (MMP-9) activity. MMP-9 transcription was previously shown to be negatively regulated by ganglioside GD1a [D. Hu, Z. Man, T. Xuan, P. Wang, T. Takaku, S. Hyuga, X.S. Yao, T. Sato, S. Yamagata, T. Yamagata, Ganglioside GD1a regulation of matrix metalloproteinase-9 (MMP-9) expression in mouse FBJ cell Lines: GD1a suppression of MMP-9 expression stimulated by PI3K-Akt and p38 though not by the Erk signaling pathway, 2006, submitted for publication.]. Zymography of MMP-9 of FBJ-M5 cells preincubated with GD1a indicated a greater decrease in activity than expected from mRNA suppression. Incubation of conditioned medium containing MMP-9 with GD1a caused MMP-9 activity to decrease. Examination was thus made to confirm that MMP-9 activity is actually suppressed and/or MMP-9 protein undergoes degradation by GD1a. GD1a was found to have no effect on MMP-9 activity and Western blots indicated GD1a not to diminish MMP-9 during electrophoresis under reducing conditions. GD1a appeared to mediate the binding of a portion of MMP-9 with certain molecules, with consequently greater molecular mass on the gel, to cause decrease in the activity of MMP-9 at the site where it would normally appear. Caution should be used in doing gelatin zymography since molecules other than GD1a may similarly work, causing decrease in MMP-9 activity in zymography.

  9. Post-translational regulation of Oct4 transcriptional activity.

    Jonathan P Saxe

    Full Text Available Oct4 is a key component of the molecular circuitry which regulates embryonic stem cell proliferation and differentiation. It is essential for maintenance of undifferentiated, pluripotent cell populations, and accomplishes these tasks by binding DNA in multiple heterodimer and homodimer configurations. Very little is known about how formation of these complexes is regulated, or the mechanisms through which Oct4 proteins respond to complex extracellular stimuli which regulate pluripotency. Here, we provide evidence for a phosphorylation-based mechanism which regulates specific Oct4 homodimer conformations. Point mutations of a putative phosphorylation site can specifically abrogate transcriptional activity of a specific homodimer assembly, with little effect on other configurations. Moreover, we performed bioinformatic predictions to identify a subset of Oct4 target genes which may be regulated by this specific assembly, and show that altering Oct4 protein levels affects transcription of Oct4 target genes which are regulated by this assembly but not others. Finally, we identified several signaling pathways which may mediate this phosphorylation and act in combination to regulate Oct4 transcriptional activity and protein stability. These results provide a mechanism for rapid and reversible alteration of Oct4 transactivation potential in response to extracellular signals.

  10. Transcriptionally Active Heterochromatin in Rye B Chromosomes[W

    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

  11. Suppression subtractive hybridization reveals transcript profiling of Chlorella under heterotrophy to photoautotrophy transition.

    Jianhua Fan

    Full Text Available Microalgae have been extensively investigated and exploited because of their competitive nutritive bioproducts and biofuel production ability. Chlorella are green algae that can grow well heterotrophically and photoautotrophically. Previous studies proved that shifting from heterotrophy to photoautotrophy in light-induced environments causes photooxidative damage as well as distinct physiologic features that lead to dynamic changes in Chlorella intracellular components, which have great potential in algal health food and biofuel production. However, the molecular mechanisms underlying the trophic transition remain unclear.In this study, suppression subtractive hybridization strategy was employed to screen and characterize genes that are differentially expressed in response to the light-induced shift from heterotrophy to photoautotrophy. Expressed sequence tags (ESTs were obtained from 770 and 803 randomly selected clones among the forward and reverse libraries, respectively. Sequence analysis identified 544 unique genes in the two libraries. The functional annotation of the assembled unigenes demonstrated that 164 (63.1% from the forward library and 62 (21.8% from the reverse showed significant similarities with the sequences in the NCBI non-redundant database. The time-course expression patterns of 38 selected differentially expressed genes further confirmed their responsiveness to a diverse trophic status. The majority of the genes enriched in the subtracted libraries were associated with energy metabolism, amino acid metabolism, protein synthesis, carbohydrate metabolism, and stress defense.The data presented here offer the first insights into the molecular foundation underlying the diverse microalgal trophic niche. In addition, the results can be used as a reference for unraveling candidate genes associated with the transition of Chlorella from heterotrophy to photoautotrophy, which holds great potential for further improving its lipid and

  12. Stimulation of cannabinoid receptor 2 (CB2 suppresses microglial activation

    Fernandez Francisco

    2005-12-01

    Full Text Available Abstract Background Activated microglial cells have been implicated in a number of neurodegenerative disorders, including Alzheimer's disease (AD, multiple sclerosis (MS, and HIV dementia. It is well known that inflammatory mediators such as nitric oxide (NO, cytokines, and chemokines play an important role in microglial cell-associated neuron cell damage. Our previous studies have shown that CD40 signaling is involved in pathological activation of microglial cells. Many data reveal that cannabinoids mediate suppression of inflammation in vitro and in vivo through stimulation of cannabinoid receptor 2 (CB2. Methods In this study, we investigated the effects of a cannabinoid agonist on CD40 expression and function by cultured microglial cells activated by IFN-γ using RT-PCR, Western immunoblotting, flow cytometry, and anti-CB2 small interfering RNA (siRNA analyses. Furthermore, we examined if the stimulation of CB2 could modulate the capacity of microglial cells to phagocytise Aβ1–42 peptide using a phagocytosis assay. Results We found that the selective stimulation of cannabinoid receptor CB2 by JWH-015 suppressed IFN-γ-induced CD40 expression. In addition, this CB2 agonist markedly inhibited IFN-γ-induced phosphorylation of JAK/STAT1. Further, this stimulation was also able to suppress microglial TNF-α and nitric oxide production induced either by IFN-γ or Aβ peptide challenge in the presence of CD40 ligation. Finally, we showed that CB2 activation by JWH-015 markedly attenuated CD40-mediated inhibition of microglial phagocytosis of Aβ1–42 peptide. Taken together, these results provide mechanistic insight into beneficial effects provided by cannabinoid receptor CB2 modulation in neurodegenerative diseases, particularly AD.

  13. Suppression of in vitro cell-mediated lympholysis generation by alloactivated lymphocytes. Examination of radioresistant suppressive activity

    Orosz, C.G.; Ferguson, R.M.

    1986-01-01

    We investigated the radioresistant (1000 rads) suppression of CML generation mediated by alloactivated murine splenocytes. Suppressive cells were generated in MLCs by stimulation of (A X 6R)F1 splenocytes with irradiated C57BL/10 splenocytes. Suppressive cells could lyse targets bearing H-2b alloantigens, but would not lyse parental B10.T(6R) or B10.A targets. Suppressive activity was detected by including the alloactivated (A X 6R)F1 cells in B10.T(6R) anti-B10.A(1R) MLCs. Relative to the suppressive (A X 6R)F1 cells, the B10.A(1R) lymphocytes display both parental and suppressor-inducing alloantigens. In the absence of a suppressive population, B10.A(1R) stimulators cause B10.T(6R) splenocytes to generate cytolytic activity specific for both H-2Db (suppressor-inducing) and H-2Kk (suppressor-borne) target determinants. The irradiated, alloactivated (A X 6R)F1 cells decrease the H-2Db-specific CML generated in this system, thus mediating apparent antigen-specific suppression. However, cytolytic activity concomitantly generated in the same culture against the unrelated H-2Kk target determinants is similarly reduced by the (A X 6R)F1 cells. Thus, radioresistant suppression by alloactivated splenocytes is not necessarily antigen-specific. The irradiated (A X 6R)F1 cells would not suppress the generation of H-2Kk-specific CTL in B10.T(6R) anti-B10.A MLCs. Hence, the irradiated (A X 6R)F1 cells can impede CML generation against third-party alloantigens if, and only if, those alloantigens are coexpressed with suppressor-inducing alloantigens on the stimulator cells in suppressed MLCs. Similar results were also obtained using a different histoincompatible lymphocyte combination

  14. COBRA1 inhibits AP-1 transcriptional activity in transfected cells

    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

  15. Reactive oxygen species activate differentiation gene transcription of acute myeloid leukemia cells via the JNK/c-JUN signaling pathway.

    Lam, Chung Fan; Yeung, Hoi Ting; Lam, Yuk Man; Ng, Ray Kit

    2018-05-01

    Reactive oxygen species (ROS) and altered cellular redox status are associated with many malignancies. Acute myeloid leukemia (AML) cells are maintained at immature state by differentiation blockade, which involves deregulation of transcription factors in myeloid differentiation. AML cells can be induced to differentiate by phorbol-12-myristate-13-acetate (PMA), which possesses pro-oxidative activity. However, the signaling events mediated by ROS in the activation of transcriptional program during AML differentiation has not been fully elucidated. Here, we investigated AML cell differentiation by treatment with PMA and ROS scavenger N-acetyl-l-cysteine (NAC). We observed elevation of intracellular ROS level in the PMA-treated AML cells, which correlated with differentiated cell morphology and increased CD11b + mature cell population. The effect of PMA can be abolished by NAC co-treatment, supporting the involvement of ROS in the process. Moreover, we demonstrated that short ROS elevation mediated cell cycle arrest, but failed to activate myeloid gene transcription; whereas prolonged ROS elevation activated JNK/c-JUN signaling pathway. Inhibition of JNK suppressed the expression of key myeloid transcriptional regulators c-JUN, SPI-1 and MAFB, and prevented AML cells from undergoing terminal differentiation. These findings provide new insights into the crucial role of JNK/c-Jun signaling pathway in the activation of transcriptional program during ROS-mediated AML differentiation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Suppression of NRF2–ARE activity sensitizes chemotherapeutic agent-induced cytotoxicity in human acute monocytic leukemia cells

    Peng, Hui; Wang, Huihui; Xue, Peng; Hou, Yongyong; Dong, Jian; Zhou, Tong; Qu, Weidong; Peng, Shuangqing; Li, Jin; Carmichael, Paul L.; Nelson, Bud; Clewell, Rebecca; Zhang, Qiang; Andersen, Melvin E.; Pi, Jingbo

    2016-01-01

    Nuclear factor erythroid 2-related factor 2 (NRF2), a master regulator of the antioxidant response element (ARE)-dependent transcription, plays a pivotal role in chemical detoxification in normal and tumor cells. Consistent with previous findings that NRF2–ARE contributes to chemotherapeutic resistance of cancer cells, we found that stable knockdown of NRF2 by lentiviral shRNA in human acute monocytic leukemia (AML) THP-1 cells enhanced the cytotoxicity of several chemotherapeutic agents, including arsenic trioxide (As 2 O 3 ), etoposide and doxorubicin. Using an ARE-luciferase reporter expressed in several human and mouse cells, we identified a set of compounds, including isonicotinic acid amides, isoniazid and ethionamide, that inhibited NRF2–ARE activity. Treatment of THP-1 cells with ethionamide, for instance, significantly reduced mRNA expression of multiple ARE-driven genes under either basal or As 2 O 3 -challenged conditions. As determined by cell viability and cell cycle, suppression of NRF2–ARE by ethionamide also significantly enhanced susceptibility of THP-1 and U937 cells to As 2 O 3 -induced cytotoxicity. In THP-1 cells, the sensitizing effect of ethionamide on As 2 O 3 -induced cytotoxicity was highly dependent on NRF2. To our knowledge, the present study is the first to demonstrate that ethionamide suppresses NRF2–ARE signaling and disrupts the transcriptional network of the antioxidant response in AML cells, leading to sensitization to chemotherapeutic agents. - Highlights: • Identification of novel inhibitors of ARE-dependent transcriptionSuppression of NRF2–ARE sensitizes THP-1 cells to chemotherapy. • Ethionamide suppresses ARE-dependent transcriptional activity. • Ethionamide and isoniazid increase the cytotoxicity of As 2 O 3 in AML cells. • Sensitization of THP-1 cells to As 2 O 3 toxicity by ethionamide is NRF2-dependent.

  17. Apamin suppresses biliary fibrosis and activation of hepatic stellate cells.

    Kim, Jung-Yeon; An, Hyun-Jin; Kim, Woon-Hae; Park, Yoon-Yub; Park, Kyung Duck; Park, Kwan-Kyu

    2017-05-01

    Cholestatic liver disease is characterized by the progressive destruction of biliary epithelial cells (BECs) followed by fibrosis, cirrhosis and liver failure. Activated hepatic stellate cells (HSCs) and portal fibroblasts are the major cellular effectors of enhanced collagen deposition in biliary fibrosis. Apamin, an 18 amino acid peptide neurotoxin found in apitoxin (bee venom), is known to block Ca2+-activated K+ channels and prevent carbon tetrachloride-induced liver fibrosis. In the present study, we aimed to ascertain whether apamin inhibits biliary fibrosis and the proliferation of HSCs. Cholestatic liver fibrosis was established in mouse models with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) feeding. Cellular assays were performed on HSC-T6 cells (rat immortalized HSCs). DDC feeding led to increased hepatic damage and proinflammtory cytokine levels. Notably, apamin treatment resulted in decreased liver injury and proinflammatory cytokine levels. Moreover, apamin suppressed the deposition of collagen, proliferation of BECs and expression of fibrogenic genes in the DDC-fed mice. In HSCs, apamin suppressed activation of HSCs by inhibiting the Smad signaling pathway. These data suggest that apamin may be a potential therapeutic target in cholestatic liver disease.

  18. [Suppression of cycling activity in sheep using parenteral progestagen treatment].

    Janett, F; Camponovo, L; Lanker, U; Hässig, M; Thun, R

    2004-03-01

    The objective of this study was to evaluate the effect of two synthetic progestagen preparations Chlormadinone acetate (CAP, Chronosyn, Veterinaria AG Zürich) and Medroxyprogesterone acetate (MPA, Nadigest, G Streuli & Co. Uznach) on cycling activity and fertility in sheep. A flock of 28 non pregnant white alpine sheep was randomly divided into three groups, A (n = 10), B (n = 9) and C (n = 9). During a period of 4 weeks the cycling activity was confirmed by blood progesterone analysis. Thereafter, the animals of group A were treated with 50 mg CAP, those of group B with 140 mg MPA and those of group C with physiological saline solution. All injections were given intramuscularly. Suppression of endogenous progesterone secretion lasted from 28 to 49 days (mean = 39 days) in group A and from 42 to 70 days (mean = 50 days) in group B. The synchronization effect of both preparations was unsatisfactory as the occurrence of first estrus was distributed over a period of 3 weeks in group A and 4 weeks in group B. These findings could also be confirmed by the lambing period which lasted 52 days in group A and 36 days in group B. Control animals lambed within 9 days due to the synchronizing effect of the ram. The first fertile estrus was observed 36 days (group A) and 45 days (group B) after the treatment. In group A all 10 animals and in groups B and C 8 of 9 ewes each became pregnant. Parenteral progestagen application with CAP and MPA is a simple, safe and reversible method of estrus suppression in the sheep. The minimal suppressive duration of 4 (CAP) and 5 weeks (MPA) is not sufficient when a period of 3 months (alpine pasture period) is desired.

  19. Activation of lysosomal function in the course of autophagy via mTORC1 suppression and autophagosome-lysosome fusion.

    Zhou, Jing; Tan, Shi-Hao; Nicolas, Valérie; Bauvy, Chantal; Yang, Nai-Di; Zhang, Jianbin; Xue, Yuan; Codogno, Patrice; Shen, Han-Ming

    2013-04-01

    Lysosome is a key subcellular organelle in the execution of the autophagic process and at present little is known whether lysosomal function is controlled in the process of autophagy. In this study, we first found that suppression of mammalian target of rapamycin (mTOR) activity by starvation or two mTOR catalytic inhibitors (PP242 and Torin1), but not by an allosteric inhibitor (rapamycin), leads to activation of lysosomal function. Second, we provided evidence that activation of lysosomal function is associated with the suppression of mTOR complex 1 (mTORC1), but not mTORC2, and the mTORC1 localization to lysosomes is not directly correlated to its regulatory role in lysosomal function. Third, we examined the involvement of transcription factor EB (TFEB) and demonstrated that TFEB activation following mTORC1 suppression is necessary but not sufficient for lysosomal activation. Finally, Atg5 or Atg7 deletion or blockage of the autophagosome-lysosome fusion process effectively diminished lysosomal activation, suggesting that lysosomal activation occurring in the course of autophagy is dependent on autophagosome-lysosome fusion. Taken together, this study demonstrates that in the course of autophagy, lysosomal function is upregulated via a dual mechanism involving mTORC1 suppression and autophagosome-lysosome fusion.

  20. Development of Transcriptional Fusions to Assess Leptospira interrogans Promoter Activity

    Cerqueira, Gustavo M.; Souza, Natalie M.; Araújo, Eduardo R.; Barros, Aline T.; Morais, Zenaide M.; Vasconcellos, Sílvio A.; Nascimento, Ana L. T. O.

    2011-01-01

    Background Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic tools for Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction of pathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. Methodology and Principal Findings A series of promoter-probe vectors carrying a reporter gene encoding green fluorescent protein (GFP) were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA) and Sphingomielynase 2 (sph2) promoters from L. interrogans and the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the non-induced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. Conclusions The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflected transcriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa. PMID:21445252

  1. Development of transcriptional fusions to assess Leptospira interrogans promoter activity.

    Gustavo M Cerqueira

    Full Text Available BACKGROUND: Leptospirosis is a zoonotic infectious disease that affects both humans and animals. The existing genetic tools for Leptospira spp. have improved our understanding of the biology of this spirochete as well as the interaction of pathogenic leptospires with the mammalian host. However, new tools are necessary to provide novel and useful information to the field. METHODOLOGY AND PRINCIPAL FINDINGS: A series of promoter-probe vectors carrying a reporter gene encoding green fluorescent protein (GFP were constructed for use in L. biflexa. They were tested by constructing transcriptional fusions between the lipL41, Leptospiral Immunoglobulin-like A (ligA and Sphingomyelinase 2 (sph2 promoters from L. interrogans and the reporter gene. ligA and sph2 promoters were the most active, in comparison to the lipL41 promoter and the non-induced controls. The results obtained are in agreement with LigA expression from the L. interrogans Fiocruz L1-130 strain. CONCLUSIONS: The novel vectors facilitated the in vitro evaluation of L. interrogans promoter activity under defined growth conditions which simulate the mammalian host environment. The fluorescence and rt-PCR data obtained closely reflected transcriptional regulation of the promoters, thus demonstrating the suitability of these vectors for assessing promoter activity in L. biflexa.

  2. Suppression of human immunodeficiency virus type 1 activity in vitro by oligonucleotides which form intramolecular tetrads.

    Rando, R F; Ojwang, J; Elbaggari, A; Reyes, G R; Tinder, R; McGrath, M S; Hogan, M E

    1995-01-27

    An oligonucleotide (I100-15) composed of only deoxyguanosine and thymidine was able to inhibit human immunodeficiency virus type-1 (HIV-1) in culture assay systems. I100-15 did not block virus entry into cells but did reduce viral-specific transcripts. As assessed by NMR and polyacrylamide gel methods, I100-15 appears to form a structure in which two stacked guanosine tetrads are connected by three two-base long loops. Structure/activity experiments indicated that formation of intramolecular guanosine tetrads was necessary to achieve maximum antiviral activity. The single deoxyguanosine nucleotide present in each loop was found to be extremely important for the overall antiviral activity. The toxicity of I100-15 was determined to be well above the 50% effective dose (ED50) in culture which yielded a high therapeutic index (> 100). The addition of a cholesterol moiety to the 3' terminus of I100-15 (I100-23) reduced the ED50 value to less than 50 nM (from 0.12 microM for I100-15) and increased the duration of viral suppression to greater than 21 days (versus 7-10 days for I100-15) after removal of the drug from infected cell cultures. The favorable therapeutic index of such molecules coupled with the prolonged suppression of HIV-1, suggest that such compounds further warrant investigation as potential therapeutic agents.

  3. Benzoxazole derivatives suppress lipopolysaccharide-induced mast cell activation.

    Cho, Kyung-Ah; Park, Minhwa; Kim, Yu-Hee; Choo, Hea-Young Park; Lee, Kyung Ho

    2018-05-01

    Mast cells are central regulators of allergic inflammation that function by releasing various proallergic inflammatory mediators, including histamine, eicosanoids and proinflammatory cytokines. Occasionally, bacterial infections may initiate or worsen allergic inflammation. A number of studies have indicated that activation of lipoxygenase in mast cells positive regulates allergic inflammatory responses by generating leukotrienes and proinflammatory cytokines. In the present study, the effects of benzoxazole derivatives on the lipopolysaccharide (LPS)‑induced expression of proinflammatory cytokines, production of histamine and surface expression of co‑stimulatory molecules on bone marrow-derived mast cells (BMMCs) were studied. The benzoxazole derivatives significantly reduced the expression of interleukin (IL)‑1β, IL‑6, IL‑13, tumor necrosis factor‑α, perilipin (PLIN) 2, and PLIN3 in BMMCs treated with LPS. Furthermore, histamine production was suppressed in BMMCs treated with LPS, or treated with phorbol-12-myristate-13-acetate/ionomycin. Benzoxazole derivatives marginally affected the surface expression of cluster of differentiation (CD)80 and CD86 on BMMCs in the presence of LPS, although LPS alone did not increase the expression of those proteins. Therefore, benzoxazole derivatives inhibited the secretion of proinflammatory cytokines in mast cells and may be potential candidate anti‑allergic agents to suppress mast cell activation.

  4. Characterization by Suppression Subtractive Hybridization of Transcripts That Are Differentially Expressed in Leaves of Anthracnose-Resistant Ramie Cultivar.

    Xuxia, Wang; Jie, Chen; Bo, Wang; Lijun, Liu; Hui, Jiang; Diluo, Tang; Dingxiang, Peng

    2012-01-01

    For the purpose of screening putative anthracnose resistance-related genes of ramie ( Boehmeria nivea L. Gaud), a cDNA library was constructed by suppression subtractive hybridization using anthracnose-resistant cultivar Huazhu no. 4. The cDNAs from Huazhu no. 4, which were infected with Colletotrichum gloeosporioides , were used as the tester and cDNAs from uninfected Huazhu no. 4 as the driver. Sequencing analysis and homology searching showed that these clones represented 132 single genes, which were assigned to functional categories, including 14 putative cellular functions, according to categories established for Arabidopsis . These 132 genes included 35 disease resistance and stress tolerance-related genes including putative heat-shock protein 90, metallothionein, PR-1.2 protein, catalase gene, WRKY family genes, and proteinase inhibitor-like protein. Partial disease-related genes were further analyzed by reverse transcription PCR and RNA gel blot. These expressed sequence tags are the first anthracnose resistance-related expressed sequence tags reported in ramie.

  5. Environmental phthalate monoesters activate pregnane X receptor-mediated transcription

    Hurst, Christopher H.; Waxman, David J.

    2004-01-01

    Phthalate esters, widely used as plasticizers in the manufacture of products made of polyvinyl chloride, induce reproductive and developmental toxicities in rodents. The mechanism that underlies these effects of phthalate exposure, including the potential role of members of the nuclear receptor superfamily, is not known. The present study investigates the effects of phthalates on the pregnane X receptor (PXR), which mediates the induction of enzymes involved in steroid metabolism and xenobiotic detoxification. The ability of phthalate monoesters to activate PXR-mediated transcription was assayed in a HepG2 cell reporter assay following transfection with mouse PXR (mPXR), human PXR (hPXR), or the hPXR allelic variants V140M, D163G, and A370T. Mono-2-ethylhexyl phthalate (MEHP) increased the transcriptional activity of both mPXR and hPXR (5- and 15-fold, respectively) with EC 50 values of 7-8 μM. mPXR and hPXR were also activated by monobenzyl phthalate (MBzP, up to 5- to 6-fold) but were unresponsive to monomethyl phthalate and mono-n-butyl phthalate (M(n)BP) at the highest concentrations tested (300 μM). hPXR-V140M and hPXR-A370T exhibited patterns of phthalate responses similar to the wild-type receptor. By contrast, hPXR-D163G was unresponsive to all phthalate monoesters tested. Further studies revealed that hPXR-D163G did respond to rifampicin, but required approximately 40-fold higher concentrations than wild-type receptor, suggesting that the ligand-binding domain D163G variant has impaired ligand-binding activity. The responsiveness of PXR to activation by phthalate monoesters demonstrated here suggests that these ubiquitous environmental chemicals may, in part, exhibit their endocrine disruptor activities by altering PXR-regulated steroid hormone metabolism with potential adverse health effects in exposed individuals

  6. Plumbagin Suppresses α-MSH-Induced Melanogenesis in B16F10 Mouse Melanoma Cells by Inhibiting Tyrosinase Activity

    Taek-In Oh

    2017-02-01

    Full Text Available Recent studies have shown that plumbagin has anti-inflammatory, anti-allergic, antibacterial, and anti-cancer activities; however, it has not yet been shown whether plumbagin suppresses alpha-melanocyte stimulating hormone (α-MSH-induced melanin synthesis to prevent hyperpigmentation. In this study, we demonstrated that plumbagin significantly suppresses α-MSH-stimulated melanin synthesis in B16F10 mouse melanoma cells. To understand the inhibitory mechanism of plumbagin on melanin synthesis, we performed cellular or cell-free tyrosinase activity assays and analyzed melanogenesis-related gene expression. We demonstrated that plumbagin directly suppresses tyrosinase activity independent of the transcriptional machinery associated with melanogenesis, which includes micropthalmia-associated transcription factor (MITF, tyrosinase (TYR, and tyrosinase-related protein 1 (TYRP1. We also investigated whether plumbagin was toxic to normal human keratinocytes (HaCaT and lens epithelial cells (B3 that may be injured by using skin-care cosmetics. Surprisingly, lower plumbagin concentrations (0.5–1 μM effectively inhibited melanin synthesis and tyrosinase activity but do not cause toxicity in keratinocytes, lens epithelial cells, and B16F10 mouse melanoma cells, suggesting that plumbagin is safe for dermal application. Taken together, these results suggest that the inhibitory effect of plumbagin to pigmentation may make it an acceptable and safe component for use in skin-care cosmetic formulations used for skin whitening.

  7. Mediator Undergoes a Compositional Change during Transcriptional Activation.

    Petrenko, Natalia; Jin, Yi; Wong, Koon Ho; Struhl, Kevin

    2016-11-03

    Mediator is a transcriptional co-activator recruited to enhancers by DNA-binding activators, and it also interacts with RNA polymerase (Pol) II as part of the preinitiation complex (PIC). We demonstrate that a single Mediator complex associates with the enhancer and core promoter in vivo, indicating that it can physically bridge these transcriptional elements. However, the Mediator kinase module associates strongly with the enhancer, but not with the core promoter, and it dissociates from the enhancer upon depletion of the TFIIH kinase. Severing the kinase module from Mediator by removing the connecting subunit Med13 does not affect Mediator association at the core promoter but increases occupancy at enhancers. Thus, Mediator undergoes a compositional change in which the kinase module, recruited via Mediator to the enhancer, dissociates from Mediator to permit association with Pol II and the PIC. As such, Mediator acts as a dynamic bridge between the enhancer and core promoter. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Active transcription and ultrastructural changes during Trypanosoma cruzi metacyclogenesis

    Ludmila R.P. Ferreira

    2008-03-01

    Full Text Available The differentiation of proliferating epimastigote forms of Trypanosoma cruzi , the protozoan parasite that causes Chagas’ disease, into the infective and non-proliferating metacyclic forms can be reproduced in the laboratory by incubating the cells in a chemically-defined medium that mimics the urine of the insect vector. Epimastigotes have a spherical nucleus, a flagellum protruding from the middle of the protozoan cell, and a disk-shaped kinetoplast - an organelle that corresponds to the mitochondrial DNA. Metacyclic trypomastigotes have an elongated shape with the flagellum protruding from the posterior portion of the cell and associated with a spherical kinetoplast. Here we describe the morphological events of this transformation and characterize a novel intermediate stage by three-dimensional reconstruction of electron microscope serial sections. This new intermediate stage is characterized by a kinetoplast compressing an already elongated nucleus, indicating that metacyclogenesis involves active movements of the flagellar structure relative to the cell body. As transcription occurs more intensely in proliferating epimastigotes than in metacyclics, we also examined the presence of RNA polymerase II and measured transcriptional activity during the differentiation process. Both the presence of the enzyme and transcriptional activity remain unchanged during all steps of metacyclogenesis. RNA polymerase II levels and transcriptional activity only decrease after metacyclics are formed. We suggest that transcription is required during the epimastigote-to-metacyclic trypomastigote differentiation process, until the kinetoplast and flagellum reach the posterior position of the parasites in the infective form.A diferenciação de formas epimastigotas (proliferativas do Trypanosoma cruzi, parasita protozoário causador da doença de Chagas, em formas metacíclicas tripomastigotas (infectivas e não proliferativas, pode ser reproduzida em laborat

  9. Selective suppression of autocatalytic caspase-3 driven by two-step transcriptional amplified human telomerase reverse transcriptase promoter on ovarian carcinoma growth in vitro and in mice.

    Song, Yue; Xin, Xing; Xia, Zhijun; Zhai, Xingyue; Shen, Keng

    2014-07-01

    The objective of our study was to construct recombinant adenovirus (rAd) AdHTVP2G5-rev-casp3, which expresses autocatalytic caspase-3 driven by human telomerase reverse transcriptase promoter (hTERTp) with a two-step transcription amplification (TSTA) system and investigate its antitumor effects on ovarian cancer in vitro and in vivo. Fluorescent detection was used to detect EGFP expression in various cells. Cell viabilities were determined using the Cell Counting Kit-8 and flow cytometry. RT-PCR and immunoblotting assays were used to detect cellular apoptotic activities. Tumor growth and survival of tumor-bearing mice were studied. The hTERTp-TSTA system showed the strongest activity in hTERT-positive cancer cells when compared with hTERTp and cytomeglovirus promoter (CMVp). In contrast, it showed no activity in hTERT‑negative HUVECs. AdHTVP2G5‑rev-casp3 markedly suppressed the survival of AO cells in a dose-dependent modality with a viability rate of 17.8 ± 3.5% at an MOI of 70, which was significantly lower than that by AdHT-rev-casp3 and Ad-rev-casp3 (rAds which express rev-caspase-3 driven by hTERTp and CMVp, respectively). In contrast, AdHTVP2G5‑rev-casp3 induced little HUVEC death with a viability rate of 92.7 ± 5.2% at the same MOI. Additionally, AdHTVP2G5-rev-casp3 (MOI=70) caused significant apoptosis in AO cells with an apoptotic rate of 42%. The tumor growth suppression rate of AdHTVP2G5-rev-casp3 was 81.52%, significantly higher than that of AdHT-rev-casp3 (54.94%) or Ad-rev-casp3 (21.35%). AdHTVP2G5-rev-casp3 significantly improved the survival of tumor-bearing mice with little liver damage, with a mean survival of 258 ± 28 days. These results showed that AdHTVP2G5-rev-casp3 caused effective apoptosis with significant tumor selectivity, strongly suppressed tumor growth and improved mouse survival with little liver toxicity. It can be a potent therapeutic agent for tumor targeted treatment of ovarian cancer.

  10. An upstream activation element exerting differential transcriptional activation on an archaeal promoter

    Peng, Nan; Xia, Qiu; Chen, Zhengjun

    2009-01-01

    S gene encoding an arabinose binding protein was characterized using an Sulfolobus islandicus reporter gene system. The minimal active araS promoter (P(araS)) was found to be 59 nucleotides long and harboured four promoter elements: an ara-box, an upstream transcription factor B-responsive element (BRE......), a TATA-box and a proximal promoter element, each of which contained important nucleotides that either greatly decreased or completely abolished promoter activity upon mutagenesis. The basal araS promoter was virtually inactive due to intrinsically weak BRE element, and the upstream activating sequence...... (UAS) ara-box activated the basal promoter by recruiting transcription factor B to its BRE. While this UAS ensured a general expression from an inactive or weak basal promoter in the presence of other tested carbon resources, it exhibited a strong arabinose-responsive transcriptional activation. To our...

  11. WRKY Transcription Factors Involved in Activation of SA Biosynthesis Genes

    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

  12. Immune-suppressive activity of punicalagin via inhibition of NFAT activation

    Lee, Sang-Ik; Kim, Byoung-Soo; Kim, Kyoung-Shin; Lee, Samkeun; Shin, Kwang-Soo; Lim, Jong-Soon

    2008-01-01

    Since T cell activation is central to the development of autoimmune diseases, we screened a natural product library comprising 1400 samples of medicinal herbal extracts, to identify compounds that suppress T cell activity. Punicalagin (PCG) isolated from the fruit of Punica granatum was identified as a potent immune suppressant, based on its inhibitory action on the activation of the nuclear factor of activated T cells (NFAT). PCG downregulated the mRNA and soluble protein expression of interleukin-2 from anti-CD3/anti-CD28-stimulated murine splenic CD4+ T cells and suppressed mixed leukocytes reaction (MLR) without exhibiting cytotoxicity to the cells. In vivo, the PCG treatment inhibited phorbol 12-myristate 13-acetate (PMA)-induced chronic ear edema in mice and decreased CD3+ T cell infiltration of the inflamed tissue. These results suggest that PCG could be a potential candidate for the therapeutics of various immune pathologies

  13. The regulation of transactivator of transcription on the activity of DNA-PKcs promoter

    Yang Tianyi; Zhang Shimeng; Qin Xia; Li Bing; Liu Xiaodan; Zhou Pingkun

    2012-01-01

    Objective: To explore the influence of human immunodeficiency virus transactivator of transcription (TAT) on the promoter activity of DNA dependent protein kinase catalytic subunit (DNA-PKcs). Methods: The truncated promoters of DNA-PKcs were cloned by PCR from the template DNA from HeLa genomic DNA, and the pGL3-basic-DNA-PKcs promoter reporter plasmids were constructed. The activity of DNA-PKcs promoters was detected by dual-luciferase reporter assay system. A Lac-repressor and Lacoperator based green fluorescent protein imaging system was used to assay the chromatin remodeling activity. Results: A series of reporter plasmids harboring the truncated promoters of DNA-PKcs from -939 bp to -1 bp were constructed. The sequence of -64 bp to-1 bp was identified as a critical element for the activity of DNA-PKes promoter. TAT can suppress the activity of DNA-PKcs promoter. TAT participates in the regulation of the large scale chromatin relaxation. Ionizing radiation attenuates the activity of TAT played in the chromatin remodeling. Conclusion: TAT represses the promoter activity of DNA repair protein DNA-PKcs, and also play a role of large scale chromatin remodeling which can te attenuated by ionizing radiation. (authors)

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

    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.

  15. Activating transcription factor 3 regulates immune and metabolic homeostasis.

    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.

  16. Comprehensive Behavioral Analysis of Activating Transcription Factor 5-Deficient Mice

    Mariko Umemura

    2017-07-01

    Full Text Available Activating transcription factor 5 (ATF5 is a member of the CREB/ATF family of basic leucine zipper transcription factors. We previously reported that ATF5-deficient (ATF5-/- mice demonstrated abnormal olfactory bulb development due to impaired interneuron supply. Furthermore, ATF5-/- mice were less aggressive than ATF5+/+ mice. Although ATF5 is widely expressed in the brain, and involved in the regulation of proliferation and development of neurons, the physiological role of ATF5 in the higher brain remains unknown. Our objective was to investigate the physiological role of ATF5 in the higher brain. We performed a comprehensive behavioral analysis using ATF5-/- mice and wild type littermates. ATF5-/- mice exhibited abnormal locomotor activity in the open field test. They also exhibited abnormal anxiety-like behavior in the light/dark transition test and open field test. Furthermore, ATF5-/- mice displayed reduced social interaction in the Crawley’s social interaction test and increased pain sensitivity in the hot plate test compared with wild type. Finally, behavioral flexibility was reduced in the T-maze test in ATF5-/- mice compared with wild type. In addition, we demonstrated that ATF5-/- mice display disturbances of monoamine neurotransmitter levels in several brain regions. These results indicate that ATF5 deficiency elicits abnormal behaviors and the disturbance of monoamine neurotransmitter levels in the brain. The behavioral abnormalities of ATF5-/- mice may be due to the disturbance of monoamine levels. Taken together, these findings suggest that ATF5-/- mice may be a unique animal model of some psychiatric disorders.

  17. Covertly active and progressing neurochemical abnormalities in suppressed HIV infection.

    Cysique, Lucette A; Jugé, Lauriane; Gates, Thomas; Tobia, Michael; Moffat, Kirsten; Brew, Bruce J; Rae, Caroline

    2018-01-01

    To assess whether HIV-related brain injury is progressive in persons with suppressed HIV infection. Seventy-three HIV+ virally suppressed men and 35 HIV- men, screened for psychiatric and alcohol/drug use disorders, underwent neuropsychological evaluation and proton magnetic resonance spectroscopy ( 1 H-MRS) at baseline and after and 23 ± 5 months. 1 H-MRS included brain regions known to be vulnerable to HIV and aging: frontal white matter (FWM), posterior cingulate cortex (PCC), and caudate area (CA). Major brain metabolites such as creatine (Cr: marker of cellular energy), N -acetyl aspartate (NAA: marker of neuronal integrity), choline (marker of cellular membrane turnover), glutamate/glutamine (excitatory/inhibitory neurotransmitter), and myo -Inositol (mI: marker of neuroinflammation) were calculated with reference to water signal. Neurocognitive decline was corrected for practice effect and baseline HIV-associated neurocognitive disorder (HAND) status. Across the study period, 44% had intact cognition, 42% stable HAND (including the single case that improved), 10% progressing HAND, and 4% incident HAND. When analyzing the neurochemical data per neurocognitive trajectories, we found decreasing PCC Cr in all subgroups compared with controls ( p < 0.002). In addition, relative to the HIV- group, stable HAND showed decreasing FWM Cr, incident HAND showed steep FWM Cr reduction, whereas progressing HAND had a sharply decreasing PCC NAA and reduced but stable CA NAA. When analyzing the neurochemical data at the group level (HIV+ vs HIV- groups), we found stable abnormal metabolite concentrations over the study period: decreased FWM and PCC Cr (both p < 0.001), decreased PCC NAA and CA NAA (both p < 0.05) and PCC mI increase ( p < 0.05). HIV duration and historical HAND had modest effects on metabolite changes. Our study reveals covertly active or progressing HIV-related brain injury in the majority of this virally suppressed cohort, reflecting ongoing

  18. Mechanical stress activates Smad pathway through PKCδ to enhance interleukin-11 gene transcription in osteoblasts.

    Shinsuke Kido

    Full Text Available BACKGROUND: Mechanical stress rapidly induces ΔFosB expression in osteoblasts, which binds to interleukin (IL-11 gene promoter to enhance IL-11 expression, and IL-11 enhances osteoblast differentiation. Because bone morphogenetic proteins (BMPs also stimulate IL-11 expression in osteoblasts, there is a possibility that BMP-Smad signaling is involved in the enhancement of osteoblast differentiation by mechanical stress. The present study was undertaken to clarify whether mechanical stress affects BMP-Smad signaling, and if so, to elucidate the role of Smad signaling in mechanical stress-induced enhancement of IL-11 gene transcription. METHODOLOGY/PRINCIPAL FINDINGS: Mechanical loading by fluid shear stress (FSS induced phosphorylation of BMP-specific receptor-regulated Smads (BR-Smads, Smad1/5, in murine primary osteoblasts (mPOBs. FSS rapidly phosphorylated Y311 of protein kinase C (PKCδ, and phosphorylated PKCδ interacted with BR-Smads to phosphorylate BR-Smads. Transfection of PKCδ siRNA or Y311F mutant PKCδ abrogated BR-Smads phosphorylation and suppressed IL-11 gene transcription enhanced by FSS. Activated BR-Smads bound to the Smad-binding element (SBE of IL-11 gene promoter and formed complex with ΔFosB/JunD heterodimer via binding to the C-terminal region of JunD. Site-directed mutagenesis in the SBE and the AP-1 site revealed that both SBE and AP-1 sites were required for full activation of IL-11 gene promoter by FSS. CONCLUSIONS/SIGNIFICANCE: These results demonstrate that PKCδ-BR-Smads pathway plays an important role in the intracellular signaling in response to mechanical stress, and that a cross-talk between PKCδ-BR-Smads and ΔFosB/JunD pathways synergistically stimulates IL-11 gene transcription in response to mechanical stress.

  19. The Ustilago maydis effector Pep1 suppresses plant immunity by inhibition of host peroxidase activity.

    Christoph Hemetsberger

    Full Text Available The corn smut Ustilago maydis establishes a biotrophic interaction with its host plant maize. This interaction requires efficient suppression of plant immune responses, which is attributed to secreted effector proteins. Previously we identified Pep1 (Protein essential during penetration-1 as a secreted effector with an essential role for U. maydis virulence. pep1 deletion mutants induce strong defense responses leading to an early block in pathogenic development of the fungus. Using cytological and functional assays we show that Pep1 functions as an inhibitor of plant peroxidases. At sites of Δpep1 mutant penetrations, H₂O₂ strongly accumulated in the cell walls, coinciding with a transcriptional induction of the secreted maize peroxidase POX12. Pep1 protein effectively inhibited the peroxidase driven oxidative burst and thereby suppresses the early immune responses of maize. Moreover, Pep1 directly inhibits peroxidases in vitro in a concentration-dependent manner. Using fluorescence complementation assays, we observed a direct interaction of Pep1 and the maize peroxidase POX12 in vivo. Functional relevance of this interaction was demonstrated by partial complementation of the Δpep1 mutant defect by virus induced gene silencing of maize POX12. We conclude that Pep1 acts as a potent suppressor of early plant defenses by inhibition of peroxidase activity. Thus, it represents a novel strategy for establishing a biotrophic interaction.

  20. Transcriptional activity of Pax3 is co-activated by TAZ

    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

  1. Jasmonate inhibits COP1 activity to suppress hypocotyl elongation and promote cotyledon opening in etiolated Arabidopsis seedlings.

    Zheng, Yuyu; Cui, Xuefei; Su, Liang; Fang, Shuang; Chu, Jinfang; Gong, Qingqiu; Yang, Jianping; Zhu, Ziqiang

    2017-06-01

    A germinating seedling undergoes skotomorphogenesis to emerge from the soil and reach for light. During this phase, the cotyledons are closed, and the hypocotyl elongates. Upon exposure to light, the seedling rapidly switches to photomorphogenesis by opening its cotyledons and suppressing hypocotyl elongation. The E3 ubiquitin ligase CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) is critical for maintaining skotomorphogenesis. Here, we report that jasmonate (JA) suppresses hypocotyl elongation and stimulates cotyledon opening in etiolated seedlings, partially phenocopying cop1 mutants in the dark. We also find that JA stabilizes several COP1-targeted transcription factors in a COP1-dependent manner. RNA-seq analysis further defines a JA-light co-modulated and cop1-dependent transcriptome, which is enriched for auxin-responsive genes and genes participating in cell wall modification. JA suppresses COP1 activity through at least two distinct mechanisms: decreasing COP1 protein accumulation in the nucleus; and reducing the physical interaction between COP1 and its activator, SUPPRESSOR OF PHYTOCHROME A-105 1 (SPA1). Our work reveals that JA suppresses COP1 activity to stabilize COP1 targets, thereby inhibiting hypocotyl elongation and stimulating cotyledon unfolding in etiolated Arabidopsis seedlings. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  2. Endogenous activation of adenosine A(1) receptors accelerates ischemic suppression of spontaneous electrocortical activity

    Ilie, Andrei; Ciocan, Dragos; Zagrean, Ana-Maria

    2006-01-01

    Cerebral ischemia induces a rapid suppression of spontaneous brain rhythms prior to major alterations in ionic homeostasis. It was found in vitro during ischemia that the rapidly formed adenosine, resulting from the intracellular breakdown of ATP, may inhibit synaptic transmission via the A(1......) receptor subtype. The link between endogenous A(1) receptor activation during ischemia and the suppression of spontaneous electrocortical activity has not yet been established in the intact brain. The aim of this study was to investigate in vivo the effects of A(1) receptor antagonism by 8-cyclopentyl-1...

  3. Cross-talk between an activator of nuclear receptors-mediated transcription and the D1 dopamine receptor signaling pathway.

    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.

  4. Large-scale transcriptome data reveals transcriptional activity of fission yeast LTR retrotransposons

    Mourier, Tobias; Willerslev, Eske

    2010-01-01

    of transcriptional activity are observed from both strands of solitary LTR sequences. Transcriptome data collected during meiosis suggests that transcription of solitary LTRs is correlated with the transcription of nearby protein-coding genes. CONCLUSIONS: Presumably, the host organism negatively regulates...

  5. Acute sex hormone suppression reduces skeletal muscle sympathetic nerve activity.

    Day, Danielle S; Gozansky, Wendolyn S; Bell, Christopher; Kohrt, Wendy M

    2011-10-01

    Comparisons of sympathetic nervous system activity (SNA) between young and older women have produced equivocal results, in part due to inadequate control for potential differences in sex hormone concentrations, age, and body composition. The aim of the present study was to determine the effect of a short-term reduction in sex hormones on tonic skeletal muscle sympathetic nerve activity (MSNA), an indirect measure of whole body SNA, using an experimental model of sex hormone deficiency in young women. We also assessed the independent effects of estradiol and progesterone add-back therapy on MSNA. MSNA was measured in 9 women (30±2 years; mean±SE) on three separate occasions: during the mid-luteal menstrual cycle phase, on the fifth day of gonadotropin-releasing hormone antagonist (GnRHant) administration, and after 5 days add-back of either estradiol (n=4) or progesterone (n=3) during continued GnRHant administration. In response to GnRHant, there were significant reductions in serum estradiol and progesterone (both psuppression attenuates MSNA and that this may be related to the suppression of progesterone rather than estradiol.

  6. Scleraxis is a transcriptional activator that regulates the expression of Tenomodulin, a marker of mature tenocytes and ligamentocytes.

    Shukunami, Chisa; Takimoto, Aki; Nishizaki, Yuriko; Yoshimoto, Yuki; Tanaka, Seima; Miura, Shigenori; Watanabe, Hitomi; Sakuma, Tetsushi; Yamamoto, Takashi; Kondoh, Gen; Hiraki, Yuji

    2018-02-16

    Tenomodulin (Tnmd) is a type II transmembrane glycoprotein predominantly expressed in tendons and ligaments. We found that scleraxis (Scx), a member of the Twist-family of basic helix-loop-helix transcription factors, is a transcriptional activator of Tnmd expression in tenocytes. During embryonic development, Scx expression preceded that of Tnmd. Tnmd expression was nearly absent in tendons and ligaments of Scx-deficient mice generated by transcription activator-like effector nucleases-mediated gene disruption. Tnmd mRNA levels were dramatically decreased during serial passages of rat tenocytes. Scx silencing by small interfering RNA significantly suppressed endogenous Tnmd mRNA levels in tenocytes. Mouse Tnmd contains five E-box sites in the ~1-kb 5'-flanking region. A 174-base pair genomic fragment containing a TATA box drives transcription in tenocytes. Enhancer activity was increased in the upstream region (-1030 to -295) of Tnmd in tenocytes, but not in NIH3T3 and C3H10T1/2 cells. Preferential binding of both Scx and Twist1 as a heterodimer with E12 or E47 to CAGATG or CATCTG and transactivation of the 5'-flanking region were confirmed by electrophoresis mobility shift and dual luciferase assays, respectively. Scx directly transactivates Tnmd via these E-boxes to positively regulate tenocyte differentiation and maturation.

  7. Compounds from Cynomorium songaricum with Estrogenic and Androgenic Activities Suppress the Oestrogen/Androgen-Induced BPH Process.

    Wang, Xueni; Tao, Rui; Yang, Jing; Miao, Lin; Wang, Yu; Munyangaju, Jose Edouard; Wichai, Nuttapong; Wang, Hong; Zhu, Yan; Liu, Erwei; Chang, Yanxu; Gao, Xiumei

    2017-01-01

    To investigate the phytoestrogenic and phytoandrogenic activities of compounds isolated from CS and uncover the role of CS in prevention of oestrogen/androgen-induced BPH. Cells were treated with CS compounds, and immunofluorescence assay was performed to detect the nuclear translocation of ER α or AR in MCF-7 or LNCaP cells; luciferase reporter assay was performed to detect ERs or AR transcriptional activity in HeLa or AD293 cells; MTT assay was performed to detect the cell proliferation of MCF-7 or LNCaP cells. Oestrogen/androgen-induced BPH model was established in rat and the anti-BPH, anti-estrogenic, and anti-androgenic activities of CS in vivo were further investigated. The nuclear translocation of ER α was stimulated by nine CS compounds, three of which also stimulated AR translocation. The transcriptional activities of ER α and ER β were induced by five compounds, within which only ECG induced AR transcriptional activity as well. Besides, ECG stimulated the proliferation of both MCF-7 cells and LNCaP cells. CS extract suppressed oestrogen/androgen-induced BPH progress in vivo by downregulation of E2 and T level in serum and alteration of the expressions of ER α , ER β , and AR in the prostate. Our data demonstrates that compounds from CS exhibit phytoestrogenic and phytoandrogenic activities, which may contribute to inhibiting the oestrogen/androgen-induced BPH development.

  8. Abrupt suppression of the transcription in the mammalian cells by X-irradiation at the violation of topological contraint of DNA superhelical loops

    Luchnik, A.N.; Dubinina, E.N.; Zbarskij, I.B.; Georgiev, G.P.; AN SSSR, Moscow. Inst. Molekulyarnoj Biologii)

    1987-01-01

    It is supposed that the whole transcription in mammalian cells depends on elastic stresses in constraint DNA loops. It is assumed that a specific molecular mechanism of transcription stop under irradiation is explained as follows: conformation of nucleosomes is changed (including DNA, histon octamer) in actively elastic-stressed chromatin. Elastically stressed DNA can promote stabilization of unfolded nucleosomes. Such nucleosomes do not interfere in RNA-polymerase conducting transcription. Nucleosomes after losing elastic stresses take wither globulra (non-active) conformation or histons dissociate with DNA, and instead of it non-active ocatmers of nucleosomes precipitate on it. The globular octamer prevents RNA-polymerase from conducting transcription through the whole length of nucleoprotein fibril. This hypothesis is substantiated by the facts that X-radiation removes High- and super-sensitivity of active chromatin to DNA-aze I as well as dissociates histons from active minichromosoms

  9. Thyroid hormone receptor inhibits hepatoma cell migration through transcriptional activation of Dickkopf 4

    Chi, Hsiang-Cheng; Liao, Chen-Hsin [Department of Biochemistry, School of Medicine, Chang-Gung University, Taoyuan 333, Taiwan, ROC (China); Huang, Ya-Hui [Medical Research Central, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan, ROC (China); Wu, Sheng-Ming; Tsai, Chung-Ying; Liao, Chia-Jung; Tseng, Yi-Hsin; Lin, Yang-Hsiang; Chen, Cheng-Yi; Chung, I-Hsiao; Wu, Tzu-I [Department of Biochemistry, School of Medicine, Chang-Gung University, Taoyuan 333, Taiwan, ROC (China); Chen, Wei-Jan [First Cardiovascular Division, Chang Gung Memorial Hospital, Taoyuan 333, Taiwan, ROC (China); Lin, Kwang-Huei, E-mail: khlin@mail.cgu.edu.tw [Department of Biochemistry, School of Medicine, Chang-Gung University, Taoyuan 333, Taiwan, ROC (China)

    2013-09-13

    Highlights: •T{sub 3} affects DKK4 mRNA and protein expression in HepG2-TR cells. •Regulation of DKK4 by T{sub 3} is at transcriptional level. •DKK4 overexpression suppresses hepatoma cell metastasis. -- Abstract: Triiodothyronine (T{sub 3}) is a potent form of thyroid hormone mediates several physiological processes including cellular growth, development, and differentiation via binding to the nuclear thyroid hormone receptor (TR). Recent studies have demonstrated critical roles of T{sub 3}/TR in tumor progression. Moreover, long-term hypothyroidism appears to be associated with the incidence of human hepatocellular carcinoma (HCC), independent of other major HCC risk factors. Dickkopf (DKK) 4, a secreted protein that antagonizes the canonical Wnt signaling pathway, is induced by T{sub 3} at both mRNA and protein levels in HCC cell lines. However, the mechanism underlying T{sub 3}-mediated regulation of DKK4 remains unknown. In the present study, the 5′ promoter region of DKK4 was serially deleted, and the reporter assay performed to localize the T{sub 3} response element (TRE). Consequently, we identified an atypical direct repeat TRE between nucleotides −1645 and −1629 conferring T{sub 3} responsiveness to the DKK4 gene. This region was further validated using chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA). Stable DKK4 overexpression in SK-Hep-1 cells suppressed cell invasion and metastatic potential, both in vivo andin vitro, via reduction of matrix metalloproteinase-2 (MMP-2) expression. Our findings collectively suggest that DKK4 upregulated by T{sub 3}/TR antagonizes the Wnt signal pathway to suppress tumor cell progression, thus providing new insights into the molecular mechanism underlying thyroid hormone activity in HCC.

  10. Endogenous fatty acid ethanolamides suppress nicotine-induced activation of mesolimbic dopamine neurons through nuclear receptors.

    Melis, Miriam; Pillolla, Giuliano; Luchicchi, Antonio; Muntoni, Anna Lisa; Yasar, Sevil; Goldberg, Steven R; Pistis, Marco

    2008-12-17

    Nicotine stimulates the activity of mesolimbic dopamine neurons, which is believed to mediate the rewarding and addictive properties of tobacco use. Accumulating evidence suggests that the endocannabinoid system might play a major role in neuronal mechanisms underlying the rewarding properties of drugs of abuse, including nicotine. Here, we investigated the modulation of nicotine effects by the endocannabinoid system on dopamine neurons in the ventral tegmental area with electrophysiological techniques in vivo and in vitro. We discovered that pharmacological inhibition of fatty acid amide hydrolase (FAAH), the enzyme that catabolizes fatty acid ethanolamides, among which the endocannabinoid anandamide (AEA) is the best known, suppressed nicotine-induced excitation of dopamine cells. Importantly, this effect was mimicked by the administration of the FAAH substrates oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), but not methanandamide, the hydrolysis resistant analog of AEA. OEA and PEA are naturally occurring lipid signaling molecules structurally related to AEA, but devoid of affinity for cannabinoid receptors. They blocked the effects of nicotine by activation of the peroxisome proliferator-activated receptor-alpha (PPAR-alpha), a nuclear receptor transcription factor involved in several aspects of lipid metabolism and energy balance. Activation of PPAR-alpha triggered a nongenomic stimulation of tyrosine kinases, which might lead to phosphorylation and negative regulation of neuronal nicotinic acetylcholine receptors. These data indicate for the first time that the anorexic lipids OEA and PEA possess neuromodulatory properties as endogenous ligands of PPAR-alpha in the brain and provide a potential new target for the treatment of nicotine addiction.

  11. Bivariate Genomic Footprinting Detects Changes in Transcription Factor Activity

    Songjoon Baek

    2017-05-01

    Full Text Available In response to activating signals, transcription factors (TFs bind DNA and regulate gene expression. TF binding can be measured by protection of the bound sequence from DNase digestion (i.e., footprint. Here, we report that 80% of TF binding motifs do not show a measurable footprint, partly because of a variable cleavage pattern within the motif sequence. To more faithfully portray the effect of TFs on chromatin, we developed an algorithm that captures two TF-dependent effects on chromatin accessibility: footprinting and motif-flanking accessibility. The algorithm, termed bivariate genomic footprinting (BaGFoot, efficiently detects TF activity. BaGFoot is robust to different accessibility assays (DNase-seq, ATAC-seq, all examined peak-calling programs, and a variety of cut bias correction approaches. BaGFoot reliably predicts TF binding and provides valuable information regarding the TFs affecting chromatin accessibility in various biological systems and following various biological events, including in cases where an absolute footprint cannot be determined.

  12. Global transcriptional regulatory network for Escherichia coli robustly connects gene expression to transcription factor activities

    Fang, Xin; Sastry, Anand; Mih, Nathan

    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 predi...

  13. RNAi screening of subtracted transcriptomes reveals tumor suppression by taurine-activated GABAA receptors involved in volume regulation

    van Nierop, Pim; Vormer, Tinke L.; Foijer, Floris; Verheij, Joanne; Lodder, Johannes C.; Andersen, Jesper B.; Mansvelder, Huibert D.; te Riele, Hein

    2018-01-01

    To identify coding and non-coding suppressor genes of anchorage-independent proliferation by efficient loss-of-function screening, we have developed a method for enzymatic production of low complexity shRNA libraries from subtracted transcriptomes. We produced and screened two LEGO (Low-complexity by Enrichment for Genes shut Off) shRNA libraries that were enriched for shRNA vectors targeting coding and non-coding polyadenylated transcripts that were reduced in transformed Mouse Embryonic Fibroblasts (MEFs). The LEGO shRNA libraries included ~25 shRNA vectors per transcript which limited off-target artifacts. Our method identified 79 coding and non-coding suppressor transcripts. We found that taurine-responsive GABAA receptor subunits, including GABRA5 and GABRB3, were induced during the arrest of non-transformed anchor-deprived MEFs and prevented anchorless proliferation. We show that taurine activates chloride currents through GABAA receptors on MEFs, causing seclusion of cell volume in large membrane protrusions. Volume seclusion from cells by taurine correlated with reduced proliferation and, conversely, suppression of this pathway allowed anchorage-independent proliferation. In human cholangiocarcinomas, we found that several proteins involved in taurine signaling via GABAA receptors were repressed. Low GABRA5 expression typified hyperproliferative tumors, and loss of taurine signaling correlated with reduced patient survival, suggesting this tumor suppressive mechanism operates in vivo. PMID:29787571

  14. Mincle suppresses Toll-like receptor 4 activation.

    Greco, Stephanie H; Mahmood, Syed Kashif; Vahle, Anne-Kristin; Ochi, Atsuo; Batel, Jennifer; Deutsch, Michael; Barilla, Rocky; Seifert, Lena; Pachter, H Leon; Daley, Donnele; Torres-Hernandez, Alejandro; Hundeyin, Mautin; Mani, Vishnu R; Miller, George

    2016-07-01

    Regulation of Toll-like receptor responses is critical for limiting tissue injury and autoimmunity in both sepsis and sterile inflammation. We found that Mincle, a C-type lectin receptor, regulates proinflammatory Toll-like receptor 4 signaling. Specifically, Mincle ligation diminishes Toll-like receptor 4-mediated inflammation, whereas Mincle deletion or knockdown results in marked hyperresponsiveness to lipopolysaccharide in vitro, as well as overwhelming lipopolysaccharide-mediated inflammation in vivo. Mechanistically, Mincle deletion does not up-regulate Toll-like receptor 4 expression or reduce interleukin 10 production after Toll-like receptor 4 ligation; however, Mincle deletion decreases production of the p38 mitogen-activated protein kinase-dependent inhibitory intermediate suppressor of cytokine signaling 1, A20, and ABIN3 and increases expression of the Toll-like receptor 4 coreceptor CD14. Blockade of CD14 mitigates the increased sensitivity of Mincle(-/-) leukocytes to Toll-like receptor 4 ligation. Collectively, we describe a major role for Mincle in suppressing Toll-like receptor 4 responses and implicate its importance in nonmycobacterial models of inflammation. © Society for Leukocyte Biology.

  15. Selective transcription and cellular proliferation induced by PDGF require histone deacetylase activity

    Catania, Annunziata; Iavarone, Carlo; Carlomagno, Stella M.; Chiariello, Mario

    2006-01-01

    Histone deacetylases (HDACs) are key regulatory enzymes involved in the control of gene expression and their inhibition by specific drugs has been widely correlated to cell cycle arrest, terminal differentiation, and apoptosis. Here, we investigated whether HDAC activity was required for PDGF-dependent signal transduction and cellular proliferation. Exposure of PDGF-stimulated NIH3T3 fibroblasts to the HDAC inhibitor trichostatin A (TSA) potently repressed the expression of a group of genes correlated to PDGF-dependent cellular growth and pro-survival activity. Moreover, we show that TSA interfered with STAT3-dependent transcriptional activity induced by PDGF. Still, neither phosphorylation nor nuclear translocation and DNA-binding in vitro and in vivo of STAT3 were affected by using TSA to interfere with PDGF stimulation. Finally, TSA treatment resulted in the suppression of PDGF-dependent cellular proliferation without affecting cellular survival of NIH3T3 cells. Our data indicate that inhibition of HDAC activity antagonizes the mitogenic effect of PDGF, suggesting that these drugs may specifically act on the expression of STAT-dependent, PDGF-responsive genes

  16. Troglitazone suppresses telomerase activity independently of PPARγ in estrogen-receptor negative breast cancer cells

    Rashid-Kolvear, Fariborz; Taboski, Michael AS; Nguyen, Johnny; Wang, Dong-Yu; Harrington, Lea A; Done, Susan J

    2010-01-01

    Breast cancer is one the highest causes of female cancer death worldwide. Many standard chemotherapeutic agents currently used to treat breast cancer are relatively non-specific and act on all rapidly dividing cells. In recent years, more specific targeted therapies have been introduced. It is known that telomerase is active in over 90% of breast cancer tumors but inactive in adjacent normal tissues. The prevalence of active telomerase in breast cancer patients makes telomerase an attractive therapeutic target. Recent evidence suggests that telomerase activity can be suppressed by peroxisome proliferator activated receptor gamma (PPARγ). However, its effect on telomerase regulation in breast cancer has not been investigated. In this study, we investigated the effect of the PPARγ ligand, troglitazone, on telomerase activity in the MDA-MB-231 breast cancer cell line. Real time RT-PCR and telomerase activity assays were used to evaluate the effect of troglitazone. MDA-MB-231 cells had PPARγ expression silenced using shRNA interference. We demonstrated that troglitazone reduced the mRNA expression of hTERT and telomerase activity in the MDA-MB-231 breast cancer cell line. Troglitazone reduced telomerase activity even in the absence of PPARγ. In agreement with this result, we found no correlation between PPARγ and hTERT mRNA transcript levels in breast cancer patients. Statistical significance was determined using Pearson correlation and the paired Student's t test. To our knowledge, this is the first time that the effect of troglitazone on telomerase activity in breast cancer cells has been investigated. Our data suggest that troglitazone may be used as an anti-telomerase agent; however, the mechanism underlying this inhibitory effect remains to be determined

  17. Use of prokaryotic transcriptional activators as metabolite biosensors in eukaryotic cells

    2018-01-01

    The present invention relates to the use of transcriptional activators from prokaryotic organisms for use in eukaryotic cells, such as yeast as sensors of intracellular and extracellular accumulation of a ligand or metabolite specifically activating this transcriptional activator in a eukaryot...

  18. Direct transcriptional activation of BT genes by NLP transcription factors is a key component of the nitrate response in Arabidopsis.

    Sato, Takeo; Maekawa, Shugo; Konishi, Mineko; Yoshioka, Nozomi; Sasaki, Yuki; Maeda, Haruna; Ishida, Tetsuya; Kato, Yuki; Yamaguchi, Junji; Yanagisawa, Shuichi

    2017-01-29

    Nitrate modulates growth and development, functioning as a nutrient signal in plants. Although many changes in physiological processes in response to nitrate have been well characterized as nitrate responses, the molecular mechanisms underlying the nitrate response are not yet fully understood. Here, we show that NLP transcription factors, which are key regulators of the nitrate response, directly activate the nitrate-inducible expression of BT1 and BT2 encoding putative scaffold proteins with a plant-specific domain structure in Arabidopsis. Interestingly, the 35S promoter-driven expression of BT2 partially rescued growth inhibition caused by reductions in NLP activity in Arabidopsis. Furthermore, simultaneous disruption of BT1 and BT2 affected nitrate-dependent lateral root development. These results suggest that direct activation of BT1 and BT2 by NLP transcriptional activators is a key component of the molecular mechanism underlying the nitrate response in Arabidopsis. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Activating Transcription Factor 3 Regulates Immune and Metabolic Homeostasis

    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

  20. Transcription factor PIF4 controls the thermosensory activation of flowering

    Kumar, S. Vinod; Lucyshyn, Doris; Jaeger, Katja E.; Aló s, Enriqueta; Alvey, Elizabeth; Harberd, Nicholas P.; Wigge, Philip A.

    2012-01-01

    Plant growth and development are strongly affected by small differences in temperature. Current climate change has already altered global plant phenology and distribution, and projected increases in temperature pose a significant challenge to agriculture. Despite the important role of temperature on plant development, the underlying pathways are unknown. It has previously been shown that thermal acceleration of flowering is dependent on the florigen, FLOWERING LOCUS T (FT). How this occurs is, however, not understood, because the major pathway known to upregulate FT, the photoperiod pathway, is not required for thermal acceleration of flowering. Here we demonstrate a direct mechanism by which increasing temperature causes the bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) to activate FT. Our findings provide a new understanding of how plants control their timing of reproduction in response to temperature. Flowering time is an important trait in crops as well as affecting the life cycles of pollinator species. A molecular understanding of how temperature affects flowering will be important for mitigating the effects of climate change. © 2012 Macmillan Publishers Limited. All rights reserved.

  1. Transcriptional activation of Mina by Sp1/3 factors.

    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.

  2. Transcription factor PIF4 controls the thermosensory activation of flowering

    Kumar, S. Vinod

    2012-03-21

    Plant growth and development are strongly affected by small differences in temperature. Current climate change has already altered global plant phenology and distribution, and projected increases in temperature pose a significant challenge to agriculture. Despite the important role of temperature on plant development, the underlying pathways are unknown. It has previously been shown that thermal acceleration of flowering is dependent on the florigen, FLOWERING LOCUS T (FT). How this occurs is, however, not understood, because the major pathway known to upregulate FT, the photoperiod pathway, is not required for thermal acceleration of flowering. Here we demonstrate a direct mechanism by which increasing temperature causes the bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) to activate FT. Our findings provide a new understanding of how plants control their timing of reproduction in response to temperature. Flowering time is an important trait in crops as well as affecting the life cycles of pollinator species. A molecular understanding of how temperature affects flowering will be important for mitigating the effects of climate change. © 2012 Macmillan Publishers Limited. All rights reserved.

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

    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.

  4. Dihydro-CDDO-trifluoroethyl amide (dh404, a novel Nrf2 activator, suppresses oxidative stress in cardiomyocytes.

    Tomonaga Ichikawa

    Full Text Available Targeting Nrf2 signaling appears to be an attractive approach for the treatment of maladaptive cardiac remodeling and dysfunction; however, pharmacological modulation of the Nrf2 pathway in the cardiovascular system remains to be established. Herein, we report that a novel synthetic triterpenoid derivative, dihydro-CDDO-trifluoroethyl amide (dh404, activates Nrf2 and suppresses oxidative stress in cardiomyocytes. Dh404 interrupted the Keap1-Cul3-Rbx1 E3 ligase complex-mediated Nrf2 ubiquitination and subsequent degradation saturating the binding capacity of Keap1 to Nrf2, thereby rendering more Nrf2 to be translocated into the nuclei to activate Nrf2-driven gene transcription. A mutant Keap1 protein containing a single cysteine-to-serine substitution at residue 151 within the BTB domain of Keap1 was resistant to dh404-induced stabilization of Nrf2 protein. In addition, dh404 did not dissociate the interaction of Nrf2 with the Keap1-Cul3-Rbx1 E3 ligase complex. Thus, it is likely that dh404 inhibits the ability of Keap1-Cul3-Rbx1 E3 ligase complex to target Nrf2 for ubiquitination and degradation via modifying Cys-151 of Keap1 to change the conformation of the complex. Moreover, dh404 was able to stabilize Nrf2 protein, to enhance Nrf2 nuclear translocation, to activate Nrf2-driven transcription, and to suppress angiotensin II (Ang II-induced oxidative stress in cardiomyocytes. Knockdown of Nrf2 almost blocked the anti-oxidative effect of dh404. Dh404 activated Nrf2 signaling in the heart. Taken together, dh404 appears to be a novel Nrf2 activator with a therapeutic potential for cardiac diseases via suppressing oxidative stress.

  5. Characterization of DNA binding, transcriptional activation, and regulated nuclear association of recombinant human NFATp

    Seto Anita G

    2000-11-01

    Full Text Available Abstract Background NFATp is one member of a family of transcriptional activators whose nuclear accumulation and hence transcriptional activity is regulated in mammalian cells. Human NFATp exists as a phosphoprotein in the cytoplasm of naive T cells. Upon antigen stimulation, NFATp is dephosphorylated, accumulates in nuclei, and functions to regulate transcription of genes including those encoding cytokines. While the properties of the DNA binding domain of NFATp have been investigated in detail, biochemical studies of the transcriptional activation and regulated association with nuclei have remained unexplored because of a lack of full length, purified recombinant NFATp. Results We developed methods for expressing and purifying full length recombinant human NFATp that has all of the properties known to be associated with native NFATp. The recombinant NFATp binds DNA on its own and cooperatively with AP-1 proteins, activates transcription in vitro, is phosphorylated, can be dephosphorylated by calcineurin, and exhibits regulated association with nuclei in vitro. Importantly, activation by recombinant NFATp in a reconstituted transcription system required regions of the protein outside of the central DNA binding domain. Conclusions We conclude that NFATp is a bona fide transcriptional activator. Moreover, the reagents and methods that we developed will facilitate future studies on the mechanisms of transcriptional activation and nuclear accumulation by NFATp, a member of an important family of transcriptional regulatory proteins.

  6. Activation tagging in tomato identifies a transcriptional regulator of anthocyanin biosynthesis, modification, and transport.

    Mathews, Helena; Clendennen, Stephanie K; Caldwell, Colby G; Liu, Xing Liang; Connors, Karin; Matheis, Nikolaus; Schuster, Debra K; Menasco, D J; Wagoner, Wendy; Lightner, Jonathan; Wagner, D Ry

    2003-08-01

    We have developed a high-throughput T-DNA insertional mutagenesis program in tomato using activation tagging to identify genes that regulate metabolic pathways. One of the activation-tagged insertion lines (ant1) showed intense purple pigmentation from the very early stage of shoot formation in culture, reflecting activation of the biosynthetic pathway leading to anthocyanin accumulation. The purple coloration resulted from the overexpression of a gene that encodes a MYB transcription factor. Vegetative tissues of ant1 plants displayed intense purple color, and the fruit showed purple spotting on the epidermis and pericarp. The gene-to-trait relationship of ant1 was confirmed by the overexpression of ANT1 in transgenic tomato and in tobacco under the control of a constitutive promoter. Suppression subtractive hybridization and RNA hybridization analysis of the purple tomato plants indicated that the overexpression of ANT1 caused the upregulation of genes that encode proteins in both the early and later steps of anthocyanidin biosynthesis as well as genes involved in the glycosylation and transport of anthocyanins into the vacuole.

  7. Transcriptional decomposition reveals active chromatin architectures and cell specific regulatory interactions

    Rennie, Sarah; Dalby, Maria; van Duin, Lucas

    2018-01-01

    Transcriptional regulation is tightly coupled with chromosomal positioning and three-dimensional chromatin architecture. However, it is unclear what proportion of transcriptional activity is reflecting such organisation, how much can be informed by RNA expression alone and how this impacts disease...... proportion of total levels and is highly informative of topological associating domain activities and organisation, revealing boundaries and chromatin compartments. Furthermore, expression data alone accurately predict individual enhancer-promoter interactions, drawing features from expression strength...... between transcription and chromatin architecture....

  8. Involvement of TORC2, a CREB co-activator, in the in vivo-specific transcriptional control of HTLV-1

    Furuta Rika A

    2009-08-01

    Full Text Available Abstract Background Human T-cell leukemia virus type 1 (HTLV-1 causes adult T -cell leukemia (ATL but the expression of HTLV-1 is strongly suppressed in the peripheral blood of infected people. However, such suppression, which may explain the long latency in the development of ATL, is readily reversible, and viral expression resumes quickly with ex vivo culture of infected T -cells. To investigate the mechanism of in vivo -specific transcriptional suppression, we established a mouse model in which mice were intraperitoneally administered syngeneic EL4 T -lymphoma cells transduced with a recombinant retrovirus expressing a GFP-Tax fusion protein, Gax, under the control of the HTLV-1 enhancer (EL4-Gax. Results Gax gene transcription was silenced in vivo but quickly up-regulated in ex vivo culture. Analysis of integrated Gax reporter gene demonstrated that neither CpG methylation of the promoter DNA nor histone modification was associated with the reversible suppression. ChIP-analysis of LTR under suppression revealed reduced promoter binding of TFIIB and Pol-II, but no change in the binding of CREB or CBP/p300 to the viral enhancer sequence. However, the expression of TORC2, a co-activator of CREB, decreased substantially in the EL4-Gax cells in vivo, and this returned to normal levels in ex vivo culture. The reduced expression of TORC2 was associated with translocation from the nucleus to the cytoplasm. A knock-down experiment with siRNA confirmed that TORC2 was the major functional protein of the three TORC-family proteins (TORC1, 2, 3 in EL4-Gax cells. Conclusion These results suggest that the TORC2 may play an important role in the in vivo -specific transcriptional control of HTLV-1. This study provides a new model for the reversible mechanism that suppresses HTLV-1 expression in vivo without the DNA methylation or hypoacetylated histones that is observed in the primary cells of most HTLV-1 -infected carriers and a substantial number of ATL

  9. Suppression of NRF2–ARE activity sensitizes chemotherapeutic agent-induced cytotoxicity in human acute monocytic leukemia cells

    Peng, Hui [The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC (United States); Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing (China); Wang, Huihui [School of Public Health, China Medical University, 77 Puhe Road, Shenyang North New Area, Shenyang (China); Xue, Peng [The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC (United States); Key Laboratory of the Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai (China); Hou, Yongyong [School of Public Health, China Medical University, 77 Puhe Road, Shenyang North New Area, Shenyang (China); Dong, Jian [The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC (United States); Institute of Biology and Medicine, Wuhan University of Science and Technology, Wuhan (China); Zhou, Tong [The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC (United States); Qu, Weidong [Key Laboratory of the Public Health Safety, Ministry of Education, School of Public Health, Fudan University, Shanghai (China); Peng, Shuangqing [Institute of Disease Control and Prevention, Academy of Military Medical Sciences, Beijing (China); Li, Jin; Carmichael, Paul L. [Unilever, Safety & Environmental Assurance Centre, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ (United Kingdom); Nelson, Bud; Clewell, Rebecca; Zhang, Qiang; Andersen, Melvin E. [The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC (United States); Pi, Jingbo, E-mail: jpi@mail.cmu.edu.cn [School of Public Health, China Medical University, 77 Puhe Road, Shenyang North New Area, Shenyang (China); The Hamner Institutes for Health Sciences, 6 Davis Drive, Research Triangle Park, NC (United States)

    2016-02-01

    Nuclear factor erythroid 2-related factor 2 (NRF2), a master regulator of the antioxidant response element (ARE)-dependent transcription, plays a pivotal role in chemical detoxification in normal and tumor cells. Consistent with previous findings that NRF2–ARE contributes to chemotherapeutic resistance of cancer cells, we found that stable knockdown of NRF2 by lentiviral shRNA in human acute monocytic leukemia (AML) THP-1 cells enhanced the cytotoxicity of several chemotherapeutic agents, including arsenic trioxide (As{sub 2}O{sub 3}), etoposide and doxorubicin. Using an ARE-luciferase reporter expressed in several human and mouse cells, we identified a set of compounds, including isonicotinic acid amides, isoniazid and ethionamide, that inhibited NRF2–ARE activity. Treatment of THP-1 cells with ethionamide, for instance, significantly reduced mRNA expression of multiple ARE-driven genes under either basal or As{sub 2}O{sub 3}-challenged conditions. As determined by cell viability and cell cycle, suppression of NRF2–ARE by ethionamide also significantly enhanced susceptibility of THP-1 and U937 cells to As{sub 2}O{sub 3}-induced cytotoxicity. In THP-1 cells, the sensitizing effect of ethionamide on As{sub 2}O{sub 3}-induced cytotoxicity was highly dependent on NRF2. To our knowledge, the present study is the first to demonstrate that ethionamide suppresses NRF2–ARE signaling and disrupts the transcriptional network of the antioxidant response in AML cells, leading to sensitization to chemotherapeutic agents. - Highlights: • Identification of novel inhibitors of ARE-dependent transcriptionSuppression of NRF2–ARE sensitizes THP-1 cells to chemotherapy. • Ethionamide suppresses ARE-dependent transcriptional activity. • Ethionamide and isoniazid increase the cytotoxicity of As{sub 2}O{sub 3} in AML cells. • Sensitization of THP-1 cells to As{sub 2}O{sub 3} toxicity by ethionamide is NRF2-dependent.

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

    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.

  11. Adenovirus DNA binding protein inhibits SrCap-activated CBP and CREB-mediated transcription

    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

  12. The adenovirus oncoprotein E1a stimulates binding of transcription factor ETF to transcriptionally activate the p53 gene.

    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.

  13. Vorinostat Modulates the Imbalance of T Cell Subsets, Suppresses Macrophage Activity, and Ameliorates Experimental Autoimmune Uveoretinitis.

    Fang, Sijie; Meng, Xiangda; Zhang, Zhuhong; Wang, Yang; Liu, Yuanyuan; You, Caiyun; Yan, Hua

    2016-03-01

    The purpose of the study was to investigate the anti-inflammatory efficiency of vorinostat, a histone deacetylase inhibitor, in experimental autoimmune uveitis (EAU). EAU was induced in female C57BL/6J mice immunized with interphotoreceptor retinoid-binding protein peptide. Vorinostat or the control treatment, phosphate-buffered saline, was administrated orally from 3 days before immunization until euthanasia at day 21 after immunization. The clinical and histopathological scores of mice were graded, and the integrity of the blood-retinal barrier was examined by Evans blue staining. T helper cell subsets were measured by flow cytometry, and the macrophage functions were evaluated with immunohistochemistry staining and immunofluorescence assays. The mRNA levels of tight junction proteins were measured by qRT-PCR. The expression levels of intraocular cytokines and transcription factors were examined by western blotting. Vorinostat relieved both clinical and histopathological manifestations of EAU in our mouse model, and the BRB integrity was maintained in vorinostat-treated mice, which had less vasculature leakage and higher mRNA and protein expressions of tight junction proteins than controls. Moreover, vorinostat repressed Th1 and Th17 cells and increased Th0 and Treg cells. Additionally, the INF-γ and IL-17A expression levels were significantly decreased, while the IL-10 level was increased by vorinostat treatment. Furthermore, due to the reduced TNF-α level, the macrophage activity was considerably inhibited in EAU mice. Finally, transcription factors, including STAT1, STAT3, and p65, were greatly suppressed by vorinostat treatment. Our data suggest that vorinostat might be a potential anti-inflammatory agent in the management of uveitis and other autoimmune inflammatory diseases.

  14. Serotonin suppresses β-casein expression via PTP1B activation in human mammary epithelial cells.

    Chiba, Takeshi; Maeda, Tomoji; Sanbe, Atsushi; Kudo, Kenzo

    2016-04-22

    Serotonin (5-hydroxytriptamine, 5-HT) has an important role in milk volume homeostasis within the mammary gland during lactation. We have previously shown that the expression of β-casein, a differentiation marker in mammary epithelial cells, is suppressed via 5-HT-mediated inhibition of signal transduction and activator of transcription 5 (STAT5) phosphorylation in the human mammary epithelial MCF-12A cell line. In addition, the reduction of β-casein in turn was associated with 5-HT7 receptor expression in the cells. The objective of this study was to determine the mechanisms underlying the 5-HT-mediated suppression of β-casein and STAT5 phosphorylation. The β-casein level and phosphorylated STAT5 (pSTAT5)/STAT5 ratio in the cells co-treated with 5-HT and a protein kinase A (PKA) inhibitor (KT5720) were significantly higher than those of cells treated with 5-HT alone. Exposure to 100 μM db-cAMP for 6 h significantly decreased the protein levels of β-casein and pSTAT5 and the pSTAT5/STAT5 ratio, and significantly increased PTP1B protein levels. In the cells co-treated with 5-HT and an extracellular signal-regulated kinase1/2 (ERK) inhibitor (FR180294) or Akt inhibitor (124005), the β-casein level and pSTAT5/STAT5 ratio were equal to those of cells treated with 5-HT alone. Treatment with 5-HT significantly induced PTP1B protein levels, whereas its increase was inhibited by KT5720. In addition, the PTP1B inhibitor sc-222227 increased the expression levels of β-casein and the pSTAT5/STAT5 ratio. Our observations indicate that PTP1B directly regulates STAT5 phosphorylation and that its activation via the cAMP/PKA pathway downstream of the 5-HT7 receptor is involved in the suppression of β-casein expression in MCF-12A cells. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. SUMOylation of the KRAB zinc-finger transcription factor PARIS/ZNF746 regulates its transcriptional activity

    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.

  16. SUMOylation of the KRAB zinc-finger transcription factor PARIS/ZNF746 regulates its transcriptional activity

    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.

  17. Redefining the transcriptional regulatory dynamics of classically and alternatively activated macrophages by deepCAGE transcriptomics

    Roy, S.; Schmeier, S.; Arner, E.; Alam, Tanvir; Parihar, S. P.; Ozturk, M.; Tamgue, O.; Kawaji, H.; de Hoon, M. J. L.; Itoh, M.; Lassmann, T.; Carninci, P.; Hayashizaki, Y.; Forrest, A. R. R.; Bajic, Vladimir B.; Guler, R.; Consortium, F.; Brombacher, F.; Suzuki, H.

    2015-01-01

    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

  18. Diarctigenin, a lignan constituent from Arctium lappa, down-regulated zymosan-induced transcription of inflammatory genes through suppression of DNA binding ability of nuclear factor-kappaB in macrophages.

    Kim, Byung Hak; Hong, Seong Su; Kwon, Soon Woo; Lee, Hwa Young; Sung, Hyeran; Lee, In-Jeong; Hwang, Bang Yeon; Song, Sukgil; Lee, Chong-Kil; Chung, Daehyun; Ahn, Byeongwoo; Nam, Sang-Yoon; Han, Sang-Bae; Kim, Youngsoo

    2008-11-01

    Diarctigenin was previously isolated as an inhibitor of nitric oxide (NO) production in macrophages from the seeds of Arctium lappa used as an alternative medicine for the treatment of inflammatory disorders. However, little is known about the molecular basis of these effects. Here, we demonstrated that diarctigenin inhibited the production of NO, prostaglandin E(2), tumor necrosis factor-alpha, and interleukin (IL)-1beta and IL-6 with IC(50) values of 6 to 12 miciroM in zymosan- or lipopolysaccharide-(LPS) activated macrophages. Diarctigenin attenuated zymosan-induced mRNA synthesis of inducible NO synthase (iNOS) and also inhibited promoter activities of iNOS and cytokine genes in the cells. Because nuclear factor (NF)-kappaB plays a pivotal role in inflammatory gene transcription, we next investigated the effect of diarctigenin on NF-kappaB activation. Diarctigenin inhibited the transcriptional activity and DNA binding ability of NF-kappaB in zymosan-activated macrophages but did not affect the degradation and phosphorylation of inhibitory kappaB (IkappaB) proteins. Moreover, diarctigenin suppressed expression vector NF-kappaB p65-elicited NF-kappaB activation and also iNOS promoter activity, indicating that the compound could directly target an NF-kappa-activating signal cascade downstream of IkappaB degradation and inhibit NF-kappaB-regulated iNOS expression. Diarctigenin also inhibited the in vitro DNA binding ability of NF-kappaB but did not affect the nuclear import of NF-kappaB p65 in the cells. Taken together, diarctigenin down-regulated zymosan- or LPS-induced inflammatory gene transcription in macrophages, which was due to direct inhibition of the DNA binding ability of NF-kappaB. Finally, this study provides a pharmacological potential of diarctigenin in the NF-kappaB-associated inflammatory disorders.

  19. RKIP Inhibits Local Breast Cancer Invasion by Antagonizing the Transcriptional Activation of MMP13.

    Ila Datar

    Full Text Available Raf Kinase Inhibitory Protein or RKIP was initially identified as a Raf-1 binding protein using the yeast 2-hybrid screen. RKIP inhibits the activation phosphorylation of MEK by Raf-1 by competitively inhibiting the binding of MEK to Raf-1 and thus exerting an inhibitory effect on the Raf-MEK-Erk pathway. RKIP has been identified as a metastasis suppressor gene. Expression of RKIP is low in cancer metastases. Although primary tumor growth remains unaffected, re- expression of RKIP inhibits cancer metastasis. Mechanistically, RKIP constrains metastasis by inhibiting angiogenesis, local invasion, intravasation, and colonization. The molecular mechanism of how RKIP inhibits these individual steps remains undefined. In our present study, using an unbiased PCR based screening and by analyzing DNA microarray expression datasets we observe that the expression of multiple metalloproteases (MMPs including MMP1, MMP3, MMP10 and MMP13 are negatively correlated with RKIP expression in breast cancer cell lines and clinical samples. Since expression of MMPs by cancer cells is important for cancer metastasis, we hypothesize that RKIP may mediate suppression of breast cancer metastasis by inhibiting multiple MMPs. We show that the expression signature of RKIP and MMPs is better at predicting high metastatic risk than the individual gene. Using a combination of loss- and gain-of-function approaches, we find that MMP13 is the cause of RKIP-mediated inhibition of local cancer invasion. Interestingly expression of MMP13 alone is not sufficient to reverse the inhibition of breast cancer cell metastasis to the lung due to the expression of RKIP. We find that RKIP negatively regulates MMP13 through the Erk2 signaling pathway and the repression of MMP13 by RKIP is transcription factor AP-1 independent. Together, our findings indicate that RKIP inhibits cancer cell invasion, in part, via MMP13 inhibition. These data also implicate RKIP in the regulation of MMP

  20. Active Center Control of Termination by RNA Polymerase III and tRNA Gene Transcription Levels In Vivo.

    Keshab Rijal

    2016-08-01

    Full Text Available The ability of RNA polymerase (RNAP III to efficiently recycle from termination to reinitiation is critical for abundant tRNA production during cellular proliferation, development and cancer. Yet understanding of the unique termination mechanisms used by RNAP III is incomplete, as is its link to high transcription output. We used two tRNA-mediated suppression systems to screen for Rpc1 mutants with gain- and loss- of termination phenotypes in S. pombe. 122 point mutation mutants were mapped to a recently solved 3.9 Å structure of yeast RNAP III elongation complex (EC; they cluster in the active center bridge helix and trigger loop, as well as the pore and funnel, the latter of which indicate involvement of the RNA cleavage domain of the C11 subunit in termination. Purified RNAP III from a readthrough (RT mutant exhibits increased elongation rate. The data strongly support a kinetic coupling model in which elongation rate is inversely related to termination efficiency. The mutants exhibit good correlations of terminator RT in vitro and in vivo, and surprisingly, amounts of transcription in vivo. Because assessing in vivo transcription can be confounded by various parameters, we used a tRNA reporter with a processing defect and a strong terminator. By ruling out differences in RNA decay rates, the data indicate that mutants with the RT phenotype synthesize more RNA than wild type cells, and than can be accounted for by their increased elongation rate. Finally, increased activity by the mutants appears unrelated to the RNAP III repressor, Maf1. The results show that the mobile elements of the RNAP III active center, including C11, are key determinants of termination, and that some of the mutations activate RNAP III for overall transcription. Similar mutations in spontaneous cancer suggest this as an unforeseen mechanism of RNAP III activation in disease.

  1. Pokemon decreases the transcriptional activity of RARα in the absence of ligand.

    Yang, Yutao; Li, Yueting; Di, Fei; Cui, Jiajun; Wang, Yue; David Xu, Zhi-Qing

    2016-12-20

    Pokemon is a transcriptional repressor that belongs to the POZ and Krüppel (POK) protein family. In this study, we investigated the potential interaction between Pokemon and retinoic acid receptor alpha (RARα) and determined the role of Pokemon in regulation of RARα transcriptional activity in the absence of ligand. We found that Pokemon could directly interact with RARα. Moreover, we demonstrated that Pokemon could decrease the transcriptional activity of RARα in the absence of ligand. Furthermore, we showed that Pokemon could repress the transcriptional activity of RARα by increasing the recruitment of nuclear receptor co-repressor (NCoR) and silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) to the retinoic acid response element (RARE) element. Taken together, these data suggest that Pokemon is a novel partner of RARα that acts as a co-repressor to regulate RARα transcriptional activity in the absence of ligand.

  2. Abscisic acid-dependent multisite phosphorylation regulates the activity of a transcription activator AREB1

    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...

  3. Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

    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

  4. The splicing regulator PTBP1 controls the activity of the transcription factor Pbx1 during neuronal differentiation.

    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.

  5. Vitamin K2 stimulates osteoblastogenesis and suppresses osteoclastogenesis by suppressing NF-κB activation.

    Yamaguchi, Masayoshi; Weitzmann, M Neale

    2011-01-01

    Several bone protective factors are reported to exhibit stimulatory activities on bone formation coupled with inhibitory effects on bone resorption; one such factor is vitamin K2. Vitamin K species [K1 (phylloquinone) and K2 (menaquinone)] have long been associated with bone protective activities and are receiving intense interest as nutritional supplements for the prevention or amelioration of bone disease in humans. However, the mechanisms of vitamin K action on the skeleton are poorly defined. Activation of the nuclear factor κB (NF-κB) signal transduction pathway is essential for osteoclast formation and resorption. By contrast, NF-κB signaling potently antagonizes osteoblast differentiation and function, prompting us to speculate that NF-κB antagonists may represent a novel class of dual anti-catabolic and pro-anabolic agents. We now show that vitamin K2 action on osteoblast and osteoclast formation and activity is accomplished by down-regulating basal and cytokine-induced NF-κB activation, by increasing IκB mRNA, in a γ-carboxylation-independent manner. Furthermore, vitamin K2 prevented repression by tumor necrosis factor α (TNFα) of SMAD signaling induced by either transforming growth factor ß (TGFß) or bone morphogenetic protein-2 (BMP-2). Vitamin K2 further antagonized receptor activator of NF-κB (RANK) ligand (RANKL)-induced NF-κB activation in osteoclast precursors. Our data provide a novel mechanism to explain the dual pro-anabolic and anti-catabolic activities of vitamin K2, and may further support the concept that pharmacological modulation of NF-κB signal transduction may constitute an effective mechanism for ameliorating pathological bone loss and for promoting bone health.

  6. Suppression of complement regulatory protein C1 inhibitor in vascular endothelial activation by inhibiting vascular cell adhesion molecule-1 action

    Zhang, Haimou; Qin, Gangjian; Liang, Gang; Li, Jinan; Chiu, Isaac; Barrington, Robert A.; Liu, Dongxu

    2007-01-01

    Increased expression of adhesion molecules by activated endothelium is a critical feature of vascular inflammation associated with the several diseases such as endotoxin shock and sepsis/septic shock. Our data demonstrated complement regulatory protein C1 inhibitor (C1INH) prevents endothelial cell injury. We hypothesized that C1INH has the ability of an anti-endothelial activation associated with suppression of expression of adhesion molecule(s). C1INH blocked leukocyte adhesion to endothelial cell monolayer in both static assay and flow conditions. In inflammatory condition, C1INH reduced vascular cell adhesion molecule (VCAM-1) expression associated with its cytoplasmic mRNA destabilization and nuclear transcription level. Studies exploring the underlying mechanism of C1INH-mediated suppression in VCAM-1 expression were related to reduction of NF-κB activation and nuclear translocation in an IκBα-dependent manner. The inhibitory effects were associated with reduction of inhibitor IκB kinase activity and stabilization of the NF-κB inhibitor IκB. These findings indicate a novel role for C1INH in inhibition of vascular endothelial activation. These observations could provide the basis for new therapeutic application of C1INH to target inflammatory processes in different pathologic situations

  7. Direct interaction of natural and synthetic catechins with signal transducer activator of transcription 1 affects both its phosphorylation and activity

    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

  8. Synergistic cooperation of MDM2 and E2F1 contributes to TAp73 transcriptional activity

    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

  9. Synergistic cooperation of MDM2 and E2F1 contributes to TAp73 transcriptional activity

    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.

  10. Vitex rotundifolia Fruit Suppresses the Proliferation of Human Colorectal Cancer Cells through Down-regulation of Cyclin D1 and CDK4 via Proteasomal-Dependent Degradation and Transcriptional Inhibition.

    Song, Hun Min; Park, Gwang Hun; Park, Su Bin; Kim, Hyun-Seok; Son, Ho-Jun; Um, Yurry; Jeong, Jin Boo

    2018-01-01

    Viticis Fructus (VF) as the dried fruit from Vitex rotundifolia L. used as a traditional medicine for treating inflammation, headache, migraine, chronic bronchitis, eye pain, and gastrointestinal infections has been reported to have antiproliferative effects against various cancer cells, including breast, lung and colorectal cancer cells. However, the molecular mechanisms by which VF mediates the inhibitory effect of the proliferation of cancer cells have not been elucidated in detail. In this study, we investigated the molecular mechanism of VF on the down-regulation of cyclin D1 and CDK4 level associated with cancer cell proliferation. VF suppressed the proliferation of human colorectal cancer cell lines such as HCT116 and SW480. VF induced decrease in cyclin D1 and CDK4 in both protein and mRNA levels. However, the protein levels of cyclin D1 and CDK4 were decreased by VF at an earlier time than the change of mRNA levels; rather it suppressed the expression of cyclin D1 and CDK4 via the proteasomal degradation. In cyclin D1 and CDK4 degradation, we found that Thr286 phosphorylation of cyclin D1 plays a pivotal role in VF-mediated cyclin D1 degradation. Subsequent experiments with several kinase inhibitors suggest that VF-mediated degradation of cyclin D1 may be dependent on GSK3[Formula: see text] and VF-mediated degradation of CDK4 is dependent on ERK1/2, p38 and GSK3[Formula: see text]. In the transcriptional regulation of cyclin D1 and CDK4, we found that VF inhibited Wnt activation associated with cyclin D1 transcriptional regulation through TCF4 down-regulation. In addition, VF treatment down-regulated c-myc expression associated CDK4 transcriptional regulation. Our results suggest that VF has potential to be a candidate for the development of chemoprevention or therapeutic agents for human colorectal cancer.

  11. Saponarin activates AMPK in a calcium-dependent manner and suppresses gluconeogenesis and increases glucose uptake via phosphorylation of CRTC2 and HDAC5.

    Seo, Woo-Duck; Lee, Ji Hae; Jia, Yaoyao; Wu, Chunyan; Lee, Sung-Joon

    2015-11-15

    This study investigated the molecular mechanism of saponarin, a flavone glucoside, in the regulation of insulin sensitivity. Saponarin suppressed the rate of gluconeogenesis and increased cellular glucose uptake in HepG2 and TE671 cells by regulating AMPK. Using an in vitro kinase assay, we showed that saponarin did not directly interact with the AMPK protein. Instead, saponarin increased intracellular calcium levels and induced AMPK phosphorylation, which was diminished by co-stimulation with STO-609, an inhibitor of CAMKKβ. Transcription of hepatic gluconeogenesis genes was upregulated by nuclear translocation of CRTC2 and HDAC5, coactivators of CREB and FoxO1 transcription factors, respectively. This nuclear translocation was inhibited by increased phosphorylation of CRTC2 and HDAC5 by saponarin-induced AMPK in HepG2 cells and suppression of CREB and FoxO1 transactivation activities in cells stimulated by saponarin. The results from a chromatin immunoprecipitation assay confirmed the reduced binding of CRTC2 on the PEPCK and G6Pase promoters. In TE671 cells, AMPK phosphorylated HDAC5, which suppressed nuclear penetration and upregulated GLUT4 transcription, leading to enhanced glucose uptake. Collectively, these results suggest that saponarin activates AMPK in a calcium-dependent manner, thus regulating gluconeogenesis and glucose uptake. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. DNA Topoisomerases Maintain Promoters in a State Competent for Transcriptional Activation in Saccharomyces cerevisiae

    Pedersen, Jakob Madsen; Fredsøe, Jacob Christian; Rødgaard, Morten Terpager

    2012-01-01

    To investigate the role of DNA topoisomerases in transcription, we have studied global gene expression in Saccharomyces cerevisiae cells deficient for topoisomerases I and II and performed single-gene analyses to support our findings. The genome-wide studies show a general transcriptional down......-regulation upon lack of the enzymes, which correlates with gene activity but not gene length. Furthermore, our data reveal a distinct subclass of genes with a strong requirement for topoisomerases. These genes are characterized by high transcriptional plasticity, chromatin regulation, TATA box presence......-depth analysis of the inducible PHO5 gene reveals that topoisomerases are essential for binding of the Pho4p transcription factor to the PHO5 promoter, which is required for promoter nucleosome removal during activation. In contrast, topoisomerases are dispensable for constitutive transcription initiation...

  13. Phosphatidylinositol response and proliferation of oxidative enzyme-activated human T lymphocytes: suppression by plasma lipoproteins

    Akeson, A.L.; Scupham, D.W.; Harmony, J.A.

    1984-01-01

    The phosphatidylinositol (PI) response and DNA synthesis of neuraminidase and galactose oxidase (NAGO)-stimulated human T lymphocytes are suppressed by low density lipoproteins (LDL). To understand the mechanism of lymphocyte activation more fully, the PI response and DNA synthesis and suppression of these events by LDL in NAGO-stimulated T lymphocytes were characterized. Between 30 min and 6 hr after NAGO stimulation, there was an increase of 32 Pi incorporation into PI without increased incorporation into the phosphorylated forms of PI or into other phospholipids. DNA synthesis as determined by [ 3 H]thymidine incorporation depended on the lymphocyte-accessory monocyte ratio and total cell density. Optimal stimulation of the PI response and DNA synthesis occurred at the same concentration of neuraminidase and galactose oxidase. While the PI response was only partially suppressed by LDL with optimal suppression at 10 to 20 micrograms of protein/ml, DNA synthesis was completely suppressed although at much higher LDL concentrations, greater than 100 micrograms protein/ml. As monocyte numbers are increased, LDL suppression of DNA synthesis is decreased. The ability of NAGO to stimulate the PI response and DNA synthesis in a similar way, and the suppression of both events by LDL, suggests the PI response is important for lymphocyte activation and proliferation. Stimulation of human T lymphocytes by oxidative mitogens, neuraminidase, and galactose oxidase caused increased phosphatidylinositol metabolism and increased DNA synthesis. Both responses were suppressed by low density lipoproteins

  14. Visual short-term memory load suppresses temporo-parietal junction activity and induces inattentional blindness.

    Todd, J Jay; Fougnie, Daryl; Marois, René

    2005-12-01

    The right temporo-parietal junction (TPJ) is critical for stimulus-driven attention and visual awareness. Here we show that as the visual short-term memory (VSTM) load of a task increases, activity in this region is increasingly suppressed. Correspondingly, increasing VSTM load impairs the ability of subjects to consciously detect the presence of a novel, unexpected object in the visual field. These results not only demonstrate that VSTM load suppresses TPJ activity and induces inattentional blindness, but also offer a plausible neural mechanism for this perceptual deficit: suppression of the stimulus-driven attentional network.

  15. Inhibition of transcriptional activity of c-JUN by SIRT1

    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

  16. The leucine zipper domains of the transcription factors GCN4 and c-Jun have ribonuclease activity.

    Yaroslav Nikolaev

    Full Text Available Basic-region leucine zipper (bZIP proteins are one of the largest transcription factor families that regulate a wide range of cellular functions. Owing to the stability of their coiled coil structure leucine zipper (LZ domains of bZIP factors are widely employed as dimerization motifs in protein engineering studies. In the course of one such study, the X-ray structure of the retro-version of the LZ moiety of yeast transcriptional activator GCN4 suggested that this retro-LZ may have ribonuclease activity. Here we show that not only the retro-LZ but also the authentic LZ of GCN4 has weak but distinct ribonuclease activity. The observed cleavage of RNA is unspecific, it is not suppressed by the ribonuclease A inhibitor RNasin and involves the breakage of 3',5'-phosphodiester bonds with formation of 2',3'-cyclic phosphates as the final products as demonstrated by HPLC/electrospray ionization mass spectrometry. Several mutants of the GCN4 leucine zipper are catalytically inactive, providing important negative controls and unequivocally associating the enzymatic activity with the peptide under study. The leucine zipper moiety of the human factor c-Jun as well as the entire c-Jun protein are also shown to catalyze degradation of RNA. The presented data, which was obtained in the test-tube experiments, adds GCN4 and c-Jun to the pool of proteins with multiple functions (also known as moonlighting proteins. If expressed in vivo, the endoribonuclease activity of these bZIP-containing factors may represent a direct coupling between transcription activation and controlled RNA turnover. As an additional result of this work, the retro-leucine zipper of GCN4 can be added to the list of functional retro-peptides.

  17. Menadione Suppresses Benzo(αpyrene-Induced Activation of Cytochromes P450 1A: Insights into a Possible Molecular Mechanism.

    Yulia A Sidorova

    Full Text Available Oxidative reactions that are catalyzed by cytochromes P450 1A (CYP1A lead to formation of carcinogenic derivatives of arylamines and polycyclic aromatic hydrocarbons (PAHs, such as the widespread environmental pollutant benzo(αpyrene (BP. These compounds upregulate CYP1A at the transcriptional level via an arylhydrocarbon receptor (AhR-dependent signaling pathway. Because of the involvement of AhR-dependent genes in chemically induced carcinogenesis, suppression of this signaling pathway could prevent tumor formation and/or progression. Here we show that menadione (a water-soluble analog of vitamin K3 inhibits BP-induced expression and enzymatic activity of both CYP1A1 and CYP1A2 in vivo (in the rat liver and BP-induced activity of CYP1A1 in vitro. Coadministration of BP and menadione reduced DNA-binding activity of AhR and increased DNA-binding activity of transcription factors Oct-1 and CCAAT/enhancer binding protein (C/EBP, which are known to be involved in negative regulation of AhR-dependent genes, in vivo. Expression of another factor involved in downregulation of CYP1A-pAhR repressor (AhRR-was lower in the liver of the rats treated with BP and menadione, indicating that the inhibitory effect of menadione on CYP1A is not mediated by this protein. Furthermore, menadione was well tolerated by the animals: no signs of acute toxicity were detected by visual examination or by assessment of weight gain dynamics or liver function. Taken together, our results suggest that menadione can be used in further studies on animal models of chemically induced carcinogenesis because menadione may suppress tumor formation and possibly progression.

  18. Menadione Suppresses Benzo(α)pyrene-Induced Activation of Cytochromes P450 1A: Insights into a Possible Molecular Mechanism.

    Sidorova, Yulia A; Perepechaeva, Maria L; Pivovarova, Elena N; Markel, Arkady L; Lyakhovich, Vyacheslav V; Grishanova, Alevtina Y

    2016-01-01

    Oxidative reactions that are catalyzed by cytochromes P450 1A (CYP1A) lead to formation of carcinogenic derivatives of arylamines and polycyclic aromatic hydrocarbons (PAHs), such as the widespread environmental pollutant benzo(α)pyrene (BP). These compounds upregulate CYP1A at the transcriptional level via an arylhydrocarbon receptor (AhR)-dependent signaling pathway. Because of the involvement of AhR-dependent genes in chemically induced carcinogenesis, suppression of this signaling pathway could prevent tumor formation and/or progression. Here we show that menadione (a water-soluble analog of vitamin K3) inhibits BP-induced expression and enzymatic activity of both CYP1A1 and CYP1A2 in vivo (in the rat liver) and BP-induced activity of CYP1A1 in vitro. Coadministration of BP and menadione reduced DNA-binding activity of AhR and increased DNA-binding activity of transcription factors Oct-1 and CCAAT/enhancer binding protein (C/EBP), which are known to be involved in negative regulation of AhR-dependent genes, in vivo. Expression of another factor involved in downregulation of CYP1A-pAhR repressor (AhRR)-was lower in the liver of the rats treated with BP and menadione, indicating that the inhibitory effect of menadione on CYP1A is not mediated by this protein. Furthermore, menadione was well tolerated by the animals: no signs of acute toxicity were detected by visual examination or by assessment of weight gain dynamics or liver function. Taken together, our results suggest that menadione can be used in further studies on animal models of chemically induced carcinogenesis because menadione may suppress tumor formation and possibly progression.

  19. Role of the σ54 Activator Interacting Domain in Bacterial Transcription Initiation

    Siegel, Alexander R. [Univ. of California, Berkeley, CA (United States); Wemmer, David E. [Univ. of California, Berkeley, CA (United States)

    2016-10-11

    Bacterial sigma factors are subunits of RNA polymerase that direct the holoenzyme to specific sets of promoters in the genome and are a central element of regulating transcription. Most polymerase holoenzymes open the promoter and initiate transcription rapidly after binding. However, polymerase containing the members of the σ54 family must be acted on by a transcriptional activator before DNA opening and initiation occur. A key domain in these transcriptional activators forms a hexameric AAA + ATPase that acts through conformational changes brought on by ATP hydrolysis. Contacts between the transcriptional activator and σ54 are primarily made through an N-terminal σ54 activator interacting domain (AID). To better understand this mechanism of bacterial transcription initiation, we characterized the σ54 AID by NMR spectroscopy and other biophysical methods and show that it is an intrinsically disordered domain in σ54 alone. In this paper, we identified a minimal construct of the Aquifex aeolicus σ54 AID that consists of two predicted helices and retains native-like binding affinity for the transcriptional activator NtrC1. Using the NtrC1 ATPase domain, bound with the non-hydrolyzable ATP analog ADP-beryllium fluoride, we studied the NtrC1–σ54 AID complex using NMR spectroscopy. We show that the σ54 AID becomes structured after associating with the core loops of the transcriptional activators in their ATP state and that the primary site of the interaction is the first predicted helix. Finally, understanding this complex, formed as the first step toward initiation, will help unravel the mechanism of σ54 bacterial transcription initiation.

  20. DNA dynamics play a role as a basal transcription factor in the positioning and regulation of gene transcription initiation

    Alexandrov, Boian S.; Gelev, Vladimir; Yoo, Sang Wook; Alexandrov, Ludmil B.; Fukuyo, Yayoi; Bishop, Alan R.; Rasmussen, Kim ?.; Usheva, Anny

    2009-01-01

    We assess the role of DNA breathing dynamics as a determinant of promoter strength and transcription start site (TSS) location. We compare DNA Langevin dynamic profiles of representative gene promoters, calculated with the extended non-linear PBD model of DNA with experimental data on transcription factor binding and transcriptional activity. Our results demonstrate that DNA dynamic activity at the TSS can be suppressed by mutations that do not affect basal transcription factor binding–DNA co...

  1. The HIV-1 transcriptional activator Tat has potent nucleic acid chaperoning activities in vitro.

    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.

  2. Assessing the Role of ETHYLENE RESPONSE FACTOR Transcriptional Repressors in Salicylic Acid-Mediated Suppression of Jasmonic Acid-Responsive Genes

    Caarls, Lotte; van der Does, Adriana; Hickman, Richard; Jansen, Wouter; van Verk, Marcel; Proietti, Silvia; Lorenzo, Oscar; Solano, Roberto; Pieterse, Corné M J; Van Wees, Saskia C M

    2017-01-01

    Salicylic acid (SA) and jasmonic acid (JA) cross-communicate in the plant immune signaling network to finely regulate induced defenses. In Arabidopsis, SA antagonizes many JA-responsive genes, partly by targeting the ETHYLENE RESPONSE FACTOR (ERF)-type transcriptional activator ORA59. Members of the

  3. Transcriptionally active LTR retrotransposons in Eucalyptus genus are differentially expressed and insertionally polymorphic.

    Marcon, Helena Sanches; Domingues, Douglas Silva; Silva, Juliana Costa; Borges, Rafael Junqueira; Matioli, Fábio Filippi; Fontes, Marcos Roberto de Mattos; Marino, Celso Luis

    2015-08-14

    In Eucalyptus genus, studies on genome composition and transposable elements (TEs) are particularly scarce. Nearly half of the recently released Eucalyptus grandis genome is composed by retrotransposons and this data provides an important opportunity to understand TE dynamics in Eucalyptus genome and transcriptome. We characterized nine families of transcriptionally active LTR retrotransposons from Copia and Gypsy superfamilies in Eucalyptus grandis genome and we depicted genomic distribution and copy number in two Eucalyptus species. We also evaluated genomic polymorphism and transcriptional profile in three organs of five Eucalyptus species. We observed contrasting genomic and transcriptional behavior in the same family among different species. RLC_egMax_1 was the most prevalent family and RLC_egAngela_1 was the family with the lowest copy number. Most families of both superfamilies have their insertions occurring Eucalyptus species. Using EST analysis and qRT-PCRs, we observed transcriptional activity in several tissues and in all evaluated species. In some families, osmotic stress increases transcript values. Our strategy was successful in isolating transcriptionally active retrotransposons in Eucalyptus, and each family has a particular genomic and transcriptional pattern. Overall, our results show that retrotransposon activity have differentially affected genome and transcriptome among Eucalyptus species.

  4. Ubiquitin ligase activity of TFIIH and the transcriptional response to DNA damage.

    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.

  5. Microglial activation induced by brain trauma is suppressed by post-injury treatment with a PARP inhibitor

    d'Avila Joana C

    2012-02-01

    Full Text Available Abstract Background Traumatic brain injury (TBI induces activation of microglia. Activated microglia can in turn increase secondary injury and impair recovery. This innate immune response requires hours to days to become fully manifest, thus providing a clinically relevant window of opportunity for therapeutic intervention. Microglial activation is regulated in part by poly(ADP-ribose polymerase-1 (PARP-1. Inhibition of PARP-1 activity suppresses NF-kB-dependent gene transcription and thereby blocks several aspects of microglial activation. Here we evaluated the efficacy of a PARP inhibitor, INO-1001, in suppressing microglial activation after cortical impact in the rat. Methods Rats were subjected to controlled cortical impact and subsequently treated with 10 mg/kg of INO-1001 (or vehicle alone beginning 20 - 24 hours after the TBI. Brains were harvested at several time points for histological evaluation of inflammation and neuronal survival, using markers for microglial activation (morphology and CD11b expression, astrocyte activation (GFAP, and neuronal survival (NeuN. Rats were also evaluated at 8 weeks after TBI using measures of forelimb dexterity: the sticky tape test, cylinder test, and vermicelli test. Results Peak microglial and astrocyte activation was observed 5 to 7 days after this injury. INO-1001 significantly reduced microglial activation in the peri-lesion cortex and ipsilateral hippocampus. No rebound inflammation was observed in rats that were treated with INO-1001 or vehicle for 12 days followed by 4 days without drug. The reduced inflammation was associated with increased neuronal survival in the peri-lesion cortex and improved performance on tests of forelimb dexterity conducted 8 weeks after TBI. Conclusions Treatment with a PARP inhibitor for 12 days after TBI, with the first dose given as long as 20 hours after injury, can reduce inflammation and improve histological and functional outcomes.

  6. In vivo bioimaging with tissue-specific transcription factor activated luciferase reporters.

    Buckley, SM; Delhove, JM; Perocheau, DP; Karda, R; Rahim, AA; Howe, SJ; Ward, NJ; Birrell, MA; Belvisi, MG; Arbuthnot, P; Johnson, MR; Waddington, SN; McKay, TR

    2015-01-01

    The application of transcription factor activated luciferase reporter cassettes in vitro is widespread but potential for in vivo application has not yet been realized. Bioluminescence imaging enables non-invasive tracking of gene expression in transfected tissues of living rodents. However the mature immune response limits luciferase expression when delivered in adulthood. We present a novel approach of tissue-targeted delivery of transcription factor activated luciferase reporter lentiviruse...

  7. The γ-secretase cleavage product of Polycystin-1 regulates TCF and CHOP-mediated transcriptional activation through a p300-dependent mechanism

    Merrick, David; Chapin, Hannah; Baggs, Julie E.; Yu, Zhiheng; Somlo, Stefan; Sun, Zhaoxia; Hogenesch, John B.; Caplan, Michael

    2011-01-01

    Summary Mutations in Pkd1, encoding polycystin-1 (PC1), cause Autosomal Dominant Polycystic Kidney Disease (ADPKD). We show that the carboxy-terminal tail (CTT) of PC1 is released by γ-secretase-mediated cleavage and regulates the Wnt and CHOP pathways by binding the transcription factors TCF and CHOP, disrupting their interaction with the common transcriptional co-activator p300. Loss of PC1 causes increased proliferation and apoptosis, while reintroducing PC1-CTT into cultured Pkd1 null cells reestablishes normal growth rate, suppresses apoptosis, and prevents cyst formation. Inhibition of γ-secretase activity impairs the ability of PC1 to suppress growth and apoptosis, and leads to cyst formation in cultured renal epithelial cells. Expression of the PC1-CTT is sufficient to rescue the dorsal body curvature phenotype in zebrafish embryos resulting from either γ-secretase inhibition or suppression of Pkd1 expression. Thus, γ-secretase-dependent release of the PC1-CTT creates a protein fragment whose expression is sufficient to suppress ADPKD-related phenotypes in vitro and in vivo. PMID:22178500

  8. The PDZ-binding motif of Yes-associated protein is required for its co-activation of TEAD-mediated CTGF transcription and oncogenic cell transforming activity

    Shimomura, Tadanori; Miyamura, Norio; Hata, Shoji; Miura, Ryota; Hirayama, Jun; Nishina, Hiroshi

    2014-01-01

    Highlights: •Loss of the PDZ-binding motif inhibits constitutively active YAP (5SA)-induced oncogenic cell transformation. •The PDZ-binding motif of YAP promotes its nuclear localization in cultured cells and mouse liver. •Loss of the PDZ-binding motif inhibits YAP (5SA)-induced CTGF transcription in cultured cells and mouse liver. -- Abstract: YAP is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes, including proliferation. Hippo pathway-dependent phosphorylation of YAP negatively regulates its function. Conversely, attenuation of Hippo-mediated phosphorylation of YAP increases its ability to stimulate proliferation and eventually induces oncogenic transformation. The C-terminus of YAP contains a highly conserved PDZ-binding motif that regulates YAP’s functions in multiple ways. However, to date, the importance of the PDZ-binding motif to the oncogenic cell transforming activity of YAP has not been determined. In this study, we disrupted the PDZ-binding motif in the YAP (5SA) protein, in which the sites normally targeted by Hippo pathway-dependent phosphorylation are mutated. We found that loss of the PDZ-binding motif significantly inhibited the oncogenic transformation of cultured cells induced by YAP (5SA). In addition, the increased nuclear localization of YAP (5SA) and its enhanced activation of TEAD-dependent transcription of the cell proliferation gene CTGF were strongly reduced when the PDZ-binding motif was deleted. Similarly, in mouse liver, deletion of the PDZ-binding motif suppressed nuclear localization of YAP (5SA) and YAP (5SA)-induced CTGF expression. Taken together, our results indicate that the PDZ-binding motif of YAP is critical for YAP-mediated oncogenesis, and that this effect is mediated by YAP’s co-activation of TEAD-mediated CTGF transcription

  9. The PDZ-binding motif of Yes-associated protein is required for its co-activation of TEAD-mediated CTGF transcription and oncogenic cell transforming activity

    Shimomura, Tadanori; Miyamura, Norio; Hata, Shoji; Miura, Ryota; Hirayama, Jun, E-mail: hirayama.dbio@mri.tmd.ac.jp; Nishina, Hiroshi, E-mail: nishina.dbio@mri.tmd.ac.jp

    2014-01-17

    Highlights: •Loss of the PDZ-binding motif inhibits constitutively active YAP (5SA)-induced oncogenic cell transformation. •The PDZ-binding motif of YAP promotes its nuclear localization in cultured cells and mouse liver. •Loss of the PDZ-binding motif inhibits YAP (5SA)-induced CTGF transcription in cultured cells and mouse liver. -- Abstract: YAP is a transcriptional co-activator that acts downstream of the Hippo signaling pathway and regulates multiple cellular processes, including proliferation. Hippo pathway-dependent phosphorylation of YAP negatively regulates its function. Conversely, attenuation of Hippo-mediated phosphorylation of YAP increases its ability to stimulate proliferation and eventually induces oncogenic transformation. The C-terminus of YAP contains a highly conserved PDZ-binding motif that regulates YAP’s functions in multiple ways. However, to date, the importance of the PDZ-binding motif to the oncogenic cell transforming activity of YAP has not been determined. In this study, we disrupted the PDZ-binding motif in the YAP (5SA) protein, in which the sites normally targeted by Hippo pathway-dependent phosphorylation are mutated. We found that loss of the PDZ-binding motif significantly inhibited the oncogenic transformation of cultured cells induced by YAP (5SA). In addition, the increased nuclear localization of YAP (5SA) and its enhanced activation of TEAD-dependent transcription of the cell proliferation gene CTGF were strongly reduced when the PDZ-binding motif was deleted. Similarly, in mouse liver, deletion of the PDZ-binding motif suppressed nuclear localization of YAP (5SA) and YAP (5SA)-induced CTGF expression. Taken together, our results indicate that the PDZ-binding motif of YAP is critical for YAP-mediated oncogenesis, and that this effect is mediated by YAP’s co-activation of TEAD-mediated CTGF transcription.

  10. Lycopene activates antioxidant enzymes and nuclear transcription factor systems in heat-stressed broilers.

    Sahin, K; Orhan, C; Tuzcu, M; Sahin, N; Hayirli, A; Bilgili, S; Kucuk, O

    2016-05-01

    This study was conducted to evaluate the effects of dietary lycopene supplementation on growth performance, antioxidant status, and muscle nuclear transcription factor [Kelch like-ECH-associated protein 1 (Keap1) and (erythroid-derived 2)-like 2 (Nrf2)] expressions in broiler chickens exposed to heat stress (HS). A total of 180 one-day-old male broiler chicks (Ross 308) were assigned randomly to one of 2×3 factorially arranged treatments: two housing temperatures (22°C for 24 h/d; thermoneutral, TN or 34°C for 8 h/d HS) and three dietary lycopene levels (0, 200, or 400 mg/kg). Each treatment consisted of three replicates of 10 birds. Birds were reared to 42 d of age. Heat stress caused reductions in feed intake and weight gain by 12.2 and 20.7% and increased feed efficiency by 10.8% (Plycopene level improved performance in both environments. Birds reared under the HS environment had lower serum and muscle lycopene concentration (0.34 vs. 0.50 μg/mL and 2.80 vs. 2.13 μg/g), activities of superoxide dismutase (151 vs. 126 U/mL and 131 vs. 155 U/mg protein), glutathione peroxidase (184 vs. 154 U/mL and 1.39 vs. 1.74 U/mg protein), and higher malondialdehyde (MDA) concentration (0.53 vs. 0.83 μg/mL and 0.78 vs. 0.45 μg/ mg protein) than birds reared under the TN environment. Changes in levels of lycopene and MDA and activities of enzymes in serum and muscle varied by the environmental temperature as dietary lycopene level increased. Moreover, increasing dietary lycopene level suppressed muscle Keap1 expression and enhanced muscle Nrf2 expression, which had increased by 150% and decreased by 40%, respectively in response to HS. In conclusion, lycopene supplementation alleviates adverse effects of HS on performance through modulating expressions of stress-related nuclear transcription factors. © 2016 Poultry Science Association Inc.

  11. SIRT7 Represses Myc Activity to Suppress ER Stress and Prevent Fatty Liver Disease

    Jiyung Shin

    2013-11-01

    Full Text Available Nonalcoholic fatty liver disease is the most common chronic liver disorder in developed countries. Its pathogenesis is poorly understood, and therapeutic options are limited. Here, we show that SIRT7, an NAD+-dependent H3K18Ac deacetylase, functions at chromatin to suppress ER stress and prevent the development of fatty liver disease. SIRT7 is induced upon ER stress and is stabilized at the promoters of ribosomal proteins through its interaction with the transcription factor Myc to silence gene expression and to relieve ER stress. SIRT7-deficient mice develop chronic hepatosteatosis resembling human fatty liver disease. Myc inactivation or pharmacological suppression of ER stress alleviates fatty liver caused by SIRT7 deficiency. Importantly, SIRT7 suppresses ER stress and reverts the fatty liver disease in diet-induced obese mice. Our study identifies SIRT7 as a cofactor of Myc for transcriptional repression and delineates a druggable regulatory branch of the ER stress response that prevents and reverts fatty liver disease.

  12. Inhibitory effects of curcumin and capsaicin on phorbol ester-induced activation of eukaryotic transcription factors, NF-kappaB and AP-1.

    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.

  13. In vitro synthesis of biologically active transcripts of tomato black ring virus satellite RNA.

    Greif, C; Hemmer, O; Demangeat, G; Fritsch, C

    1990-04-01

    Synthetic transcripts of tomato black ring virus satellite RNA (TBRV satRNA), isolate L, were prepared from cDNA cloned in the Bluescribe transcription vector. Transcripts with 49 (T49L) or two (T2GL) extra nucleotides at their 5' ends and 42 extra nucleotides at their 3' ends were able to induce, but to different extents, the synthesis in vitro of the satRNA-encoded 48K protein. However, when inoculated into Chenopodium quinoa together with TBRV L genomic RNAs, only T2GL was biologically active, in the presence or absence of a 5' cap analogue in the transcription reactions. Analysis of the 5' and 3' termini of the satRNA isolated from plants showed that nonviral extensions were not maintained in the transcript progeny.

  14. An activator of transcription regulates phage TP901-1 late gene expression

    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...

  15. Suppression of a NAC-Like Transcription Factor Gene Improves Boron-Toxicity Tolerance in Rice1

    Ochiai, Kumiko; Shimizu, Akifumi; Okumoto, Yutaka; Fujiwara, Toru; Matoh, Toru

    2011-01-01

    We identified a gene responsible for tolerance to boron (B) toxicity in rice (Oryza sativa), named BORON EXCESS TOLERANT1. Using recombinant inbred lines derived from the B-toxicity-sensitive indica-ecotype cultivar IR36 and the tolerant japonica-ecotype cultivar Nekken 1, the region responsible for tolerance to B toxicity was narrowed to 49 kb on chromosome 4. Eight genes are annotated in this region. The DNA sequence in this region was compared between the B-toxicity-sensitive japonica cultivar Wataribune and the B-toxicity-tolerant japonica cultivar Nipponbare by eco-TILLING analysis and revealed a one-base insertion mutation in the open reading frame sequence of the gene Os04g0477300. The gene encodes a NAC (NAM, ATAF, and CUC)-like transcription factor and the function of the transcript is abolished in B-toxicity-tolerant cultivars. Transgenic plants in which the expression of Os04g0477300 is abolished by RNA interference gain tolerance to B toxicity. PMID:21543724

  16. Platelet activating factor receptor binding plays a critical role in jet fuel-induced immune suppression

    Ramos, Gerardo; Kazimi, Nasser; Nghiem, Dat X.; Walterscheid, Jeffrey P.; Ullrich, Stephen E.

    2004-01-01

    Applying military jet fuel (JP-8) or commercial jet fuel (Jet-A) to the skin of mice suppresses the immune response in a dose-dependant manner. The release of biological response modifiers, particularly prostaglandin E 2 (PGE 2 ), is a critical step in activating immune suppression. Previous studies have shown that injecting selective cyclooxygenase-2 inhibitors into jet fuel-treated mice blocks immune suppression. Because the inflammatory phospholipid mediator, platelet-activating factor (PAF), up-regulates cyclooxygenase-2 production and PGE 2 synthesis by keratinocytes, we tested the hypothesis that PAF-receptor binding plays a role in jet fuel-induced immune suppression. Treating keratinocyte cultures with PAF and/or jet fuel (JP-8 and Jet-A) stimulates PGE 2 secretion. Jet fuel-induced PGE 2 production was suppressed by treating the keratinocytes with specific PAF-receptor antagonists. Injecting mice with PAF, or treating the skin of the mice with JP-8, or Jet-A, induced immune suppression. Jet fuel-induced immune suppression was blocked when the jet fuel-treated mice were injected with PAF-receptor antagonists before treatment. Jet fuel treatment has been reported to activate oxidative stress and treating the mice with anti-oxidants (Vitamins C, or E or beta-hydroxy toluene), before jet fuel application, interfered with immune suppression. These findings confirm previous studies showing that PAF-receptor binding can modulate immune function. Furthermore, they suggest that PAF-receptor binding may be an early event in the induction of immune suppression by immunotoxic environmental agents that target the skin

  17. A large family of antivirulence regulators modulates the effects of transcriptional activators in Gram-negative pathogenic bacteria.

    Araceli E Santiago

    2014-05-01

    Full Text Available We have reported that transcription of a hypothetical small open reading frame (orf60 in enteroaggregative E. coli (EAEC strain 042 is impaired after mutation of aggR, which encodes a global virulence activator. We have also reported that the cryptic orf60 locus was linked to protection against EAEC diarrhea in two epidemiologic studies. Here, we report that the orf60 product acts as a negative regulator of aggR itself. The orf60 protein product lacks homology to known repressors, but displays 44-100% similarity to at least fifty previously undescribed small (<10 kDa hypothetical proteins found in many gram negative pathogen genomes. Expression of orf60 homologs from enterotoxigenic E. coli (ETEC repressed the expression of the AraC-transcriptional ETEC regulator CfaD/Rns and its regulon in ETEC strain H10407. Complementation in trans of EAEC 042orf60 by orf60 homologs from ETEC and the mouse pathogen Citrobacter rodentium resulted in dramatic suppression of aggR. A C. rodentium orf60 homolog mutant showed increased levels of activator RegA and increased colonization of the adult mouse. We propose the name Aar (AggR-activated regulator for the clinically and epidemiologically important orf60 product in EAEC, and postulate the existence of a large family of homologs among pathogenic Enterobacteriaceae and Pasteurellaceae. We propose the name ANR (AraC Negative Regulators for this family.

  18. Identification of cis-regulatory sequences that activate transcription in the suspensor of plant embryos.

    Kawashima, Tomokazu; Wang, Xingjun; Henry, Kelli F; Bi, Yuping; Weterings, Koen; Goldberg, Robert B

    2009-03-03

    Little is known about the molecular mechanisms by which the embryo proper and suspensor of plant embryos activate specific gene sets shortly after fertilization. We analyzed the upstream region of the scarlet runner bean (Phaseolus coccineus) G564 gene to understand how genes are activated specifically within the suspensor during early embryo development. Previously, we showed that the G564 upstream region has a block of tandem repeats, which contain a conserved 10-bp motif (GAAAAG(C)/(T)GAA), and that deletion of these repeats results in a loss of suspensor transcription. Here, we use gain-of-function (GOF) experiments with transgenic globular-stage tobacco embryos to show that only 1 of the 5 tandem repeats is required to drive suspensor-specific transcription. Fine-scale deletion and scanning mutagenesis experiments with 1 tandem repeat uncovered a 54-bp region that contains all of the sequences required to activate transcription in the suspensor, including the 10-bp motif (GAAAAGCGAA) and a similar 10-bp-like motif (GAAAAACGAA). Site-directed mutagenesis and GOF experiments indicated that both the 10-bp and 10-bp-like motifs are necessary, but not sufficient to activate transcription in the suspensor, and that a sequence (TTGGT) between the 10-bp and the 10-bp-like motifs is also necessary for suspensor transcription. Together, these data identify sequences that are required to activate transcription in the suspensor of a plant embryo after fertilization.

  19. Active Suppression of Drilling System Vibrations For Deep Drilling

    Raymond, David W.; Blankenship, Douglas A.; Buerger, Stephen; Mesh, Mikhail; Radigan, William Thomas; Su, Jiann-Cherng

    2015-10-01

    The dynamic stability of deep drillstrings is challenged by an inability to impart controllability with ever-changing conditions introduced by geology, depth, structural dynamic properties and operating conditions. A multi-organizational LDRD project team at Sandia National Laboratories successfully demonstrated advanced technologies for mitigating drillstring vibrations to improve the reliability of drilling systems used for construction of deep, high-value wells. Using computational modeling and dynamic substructuring techniques, the benefit of controllable actuators at discrete locations in the drillstring is determined. Prototype downhole tools were developed and evaluated in laboratory test fixtures simulating the structural dynamic response of a deep drillstring. A laboratory-based drilling applicability demonstration was conducted to demonstrate the benefit available from deployment of an autonomous, downhole tool with self-actuation capabilities in response to the dynamic response of the host drillstring. A concept is presented for a prototype drilling tool based upon the technical advances. The technology described herein is the subject of U.S. Patent Application No. 62219481, entitled "DRILLING SYSTEM VIBRATION SUPPRESSION SYSTEMS AND METHODS", filed September 16, 2015.

  20. Active vertical tail buffeting suppression based on macro fiber composites

    Zou, Chengzhe; Li, Bin; Liang, Li; Wang, Wei

    2016-04-01

    Aerodynamic buffet is unsteady airflow exerting forces onto a surface, which can lead to premature fatigue damage of aircraft vertical tail structures, especially for aircrafts with twin vertical tails at high angles of attack. In this work, Macro Fiber Composite (MFC), which can provide strain actuation, was used as the actuator for the buffet-induced vibration control, and the positioning of the MFC patches was led by the strain energy distribution on the vertical tail. Positive Position Feedback (PPF) control algorithm has been widely used for its robustness and simplicity in practice, and consequently it was developed to suppress the buffet responses of first bending and torsional mode of vertical tail. However, its performance is usually attenuated by the phase contributions from non-collocated sensor/actuator configuration and plants. The phase lag between the input and output signals of the control system was identified experimentally, and the phase compensation was considered in the PPF control algorithm. The simulation results of the amplitude frequency of the closed-loop system showed that the buffet response was alleviated notably around the concerned bandwidth. Then the wind tunnel experiment was conducted to verify the effectiveness of MFC actuators and compensated PPF, and the Root Mean Square (RMS) of the acceleration response was reduced 43.4%, 28.4% and 39.5%, respectively, under three different buffeting conditions.

  1. Extinction cross-section suppression and active acoustic invisibility cloaking

    Mitri, F. G.

    2017-10-01

    Invisibility in its canonical form requires rendering a zero extinction cross-section (or energy efficiency) from an active or a passive object. This work demonstrates the successful theoretical realization of this physical effect for an active cylindrically radiating acoustic body, undergoing periodic axisymmetric harmonic vibrations near a flat rigid boundary. Radiating, amplification and extinction cross-sections of the active source are defined. Assuming monopole and dipole modal oscillations of the circular source, conditions are found where the extinction energy efficiency factor of the active source vanishes, achieving total invisibility with minimal influence of the source size. It also takes positive or negative values, depending on its size and distance from the boundary. Moreover, the amplification energy efficiency factor is negative for the acoustically-active source. These effects also occur for higher-order modal oscillations of the active source. The results find potential applications in the development of acoustic cloaking devices and invisibility.

  2. Extinction cross-section suppression and active acoustic invisibility cloaking

    Mitri, F G

    2017-01-01

    Invisibility in its canonical form requires rendering a zero extinction cross-section (or energy efficiency) from an active or a passive object. This work demonstrates the successful theoretical realization of this physical effect for an active cylindrically radiating acoustic body, undergoing periodic axisymmetric harmonic vibrations near a flat rigid boundary. Radiating, amplification and extinction cross-sections of the active source are defined. Assuming monopole and dipole modal oscillations of the circular source, conditions are found where the extinction energy efficiency factor of the active source vanishes, achieving total invisibility with minimal influence of the source size. It also takes positive or negative values, depending on its size and distance from the boundary. Moreover, the amplification energy efficiency factor is negative for the acoustically-active source. These effects also occur for higher-order modal oscillations of the active source. The results find potential applications in the development of acoustic cloaking devices and invisibility. (letter)

  3. Modeling post-transcriptional regulation activity of small non-coding RNAs in Escherichia coli.

    Wang, Rui-Sheng; Jin, Guangxu; Zhang, Xiang-Sun; Chen, Luonan

    2009-04-29

    Transcriptional regulation is a fundamental process in biological systems, where transcription factors (TFs) have been revealed to play crucial roles. In recent years, in addition to TFs, an increasing number of non-coding RNAs (ncRNAs) have been shown to mediate post-transcriptional processes and regulate many critical pathways in both prokaryotes and eukaryotes. On the other hand, with more and more high-throughput biological data becoming available, it is possible and imperative to quantitatively study gene regulation in a systematic and detailed manner. Most existing studies for inferring transcriptional regulatory interactions and the activity of TFs ignore the possible post-transcriptional effects of ncRNAs. In this work, we propose a novel framework to infer the activity of regulators including both TFs and ncRNAs by exploring the expression profiles of target genes and (post)transcriptional regulatory relationships. We model the integrated regulatory system by a set of biochemical reactions which lead to a log-bilinear problem. The inference process is achieved by an iterative algorithm, in which two linear programming models are efficiently solved. In contrast to available related studies, the effects of ncRNAs on transcription process are considered in this work, and thus more reasonable and accurate reconstruction can be expected. In addition, the approach is suitable for large-scale problems from the viewpoint of computation. Experiments on two synthesized data sets and a model system of Escherichia coli (E. coli) carbon source transition from glucose to acetate illustrate the effectiveness of our model and algorithm. Our results show that incorporating the post-transcriptional regulation of ncRNAs into system model can mine the hidden effects from the regulation activity of TFs in transcription processes and thus can uncover the biological mechanisms in gene regulation in a more accurate manner. The software for the algorithm in this paper is available

  4. Modeling the Effects of Vorinostat In Vivo Reveals both Transient and Delayed HIV Transcriptional Activation and Minimal Killing of Latently Infected Cells.

    Ke, Ruian; Lewin, Sharon R; Elliott, Julian H; Perelson, Alan S

    2015-10-01

    Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Furthermore, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.

  5. Activated AMPK inhibits PPAR-{alpha} and PPAR-{gamma} transcriptional activity in hepatoma cells.

    Sozio, Margaret S; Lu, Changyue; Zeng, Yan; Liangpunsakul, Suthat; Crabb, David W

    2011-10-01

    AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-α (PPAR-α) are critical regulators of short-term and long-term fatty acid oxidation, respectively. We examined whether the activities of these molecules were coordinately regulated. H4IIEC3 cells were transfected with PPAR-α and PPAR-γ expression plasmids and a peroxisome-proliferator-response element (PPRE) luciferase reporter plasmid. The cells were treated with PPAR agonists (WY-14,643 and rosiglitazone), AMPK activators 5-aminoimidazole-4-carboxamide riboside (AICAR) and metformin, and the AMPK inhibitor compound C. Both AICAR and metformin decreased basal and WY-14,643-stimulated PPAR-α activity; compound C increased agonist-stimulated reporter activity and partially reversed the effect of the AMPK activators. Similar effects on PPAR-γ were seen, with both AICAR and metformin inhibiting PPRE reporter activity. Compound C increased basal PPAR-γ activity and rosiglitazone-stimulated activity. In contrast, retinoic acid receptor-α (RAR-α), another nuclear receptor that dimerizes with retinoid X receptor (RXR), was largely unaffected by the AMPK activators. Compound C modestly increased AM580 (an RAR agonist)-stimulated activity. The AMPK activators did not affect PPAR-α binding to DNA, and there was no consistent correlation between effects of the AMPK activators and inhibitor on PPAR and the nuclear localization of AMPK-α subunits. Expression of either a constitutively active or dominant negative AMPK-α inhibited basal and WY-14,643-stimulated PPAR-α activity and basal and rosiglitazone-stimulated PPAR-γ activity. We concluded that the AMPK activators AICAR and metformin inhibited transcriptional activities of PPAR-α and PPAR-γ, whereas inhibition of AMPK with compound C activated both PPARs. The effects of AMPK do not appear to be mediated through effects on RXR or on PPAR/RXR binding to DNA. These effects are independent of kinase activity and instead appear to

  6. Antiviral RNA silencing suppression activity of Tomato spotted wilt virus NSs protein.

    Ocampo Ocampo, T; Gabriel Peralta, S M; Bacheller, N; Uiterwaal, S; Knapp, A; Hennen, A; Ochoa-Martinez, D L; Garcia-Ruiz, H

    2016-06-17

    In addition to regulating gene expression, RNA silencing is an essential antiviral defense system in plants. Triggered by double-stranded RNA, silencing results in degradation or translational repression of target transcripts. Viruses are inducers and targets of RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressors that interfere with this process, such as the Tomato spotted wilt virus (TSWV) NSs protein. The mechanism by which NSs suppresses RNA silencing and its role in viral infection and movement remain to be determined. We cloned NSs from the Hawaii isolate of TSWV and using two independent assays show for the first time that this protein restored pathogenicity and supported the formation of local infection foci by suppressor-deficient Turnip mosaic virus and Turnip crinkle virus. Demonstrating the suppression of RNA silencing directed against heterologous viruses establishes the foundation to determine the means used by NSs to block this antiviral process.

  7. Claudin-1 has tumor suppressive activity and is a direct target of RUNX3 in gastric epithelial cells.

    Chang, Ti Ling; Ito, Kosei; Ko, Tun Kiat; Liu, Qiang; Salto-Tellez, Manuel; Yeoh, Khay Guan; Fukamachi, Hiroshi; Ito, Yoshiaki

    2010-01-01

    The transcription factor RUNX3 is a gastric tumor suppressor. Tumorigenic Runx3(-/-) gastric epithelial cells attach weakly to each other, compared with nontumorigenic Runx3(+/+) cells. We aimed to identify RUNX3 target genes that promote cell-cell contact to improve our understanding of RUNX3's role in suppressing gastric carcinogenesis. We compared gene expression profiles of Runx3(+/+) and Runx3(-/-) cells and observed down-regulation of genes associated with cell-cell adhesion in Runx3(-/-) cells. Reporter, mobility shift, and chromatin immunoprecipitation assays were used to examine the regulation of these genes by RUNX3. Tumorigenesis assays and immunohistological analyses of human gastric tumors were performed to confirm the role of the candidate genes in gastric tumor development. Mobility shift and chromatin immunoprecipitation assays revealed that the promoter activity of the gene that encodes the tight junction protein claudin-1 was up-regulated via the binding of RUNX3 to the RUNX consensus sites. The tumorigenicity of gastric epithelial cells from Runx3(-/-) mice was significantly reduced by restoration of claudin-1 expression, whereas knockdown of claudin-1 increased the tumorigenicity of human gastric cancer cells. Concomitant expression of RUNX3 and claudin-1 was observed in human normal gastric epithelium and cancers. The tight junction protein claudin-1 has gastric tumor suppressive activity and is a direct transcriptional target of RUNX3. Claudin-1 is down-regulated during the epithelial-mesenchymal transition; RUNX3 might therefore act as a tumor suppressor to antagonize the epithelial-mesenchymal transition. Copyright 2010 AGA Institute. Published by Elsevier Inc. All rights reserved.

  8. Transcriptional activation by the thyroid hormone receptor through ligand-dependent receptor recruitment and chromatin remodelling.

    Grøntved, Lars; Waterfall, Joshua J; Kim, Dong Wook; Baek, Songjoon; Sung, Myong-Hee; Zhao, Li; Park, Jeong Won; Nielsen, Ronni; Walker, Robert L; Zhu, Yuelin J; Meltzer, Paul S; Hager, Gordon L; Cheng, Sheue-yann

    2015-04-28

    A bimodal switch model is widely used to describe transcriptional regulation by the thyroid hormone receptor (TR). In this model, the unliganded TR forms stable, chromatin-bound complexes with transcriptional co-repressors to repress transcription. Binding of hormone dissociates co-repressors and facilitates recruitment of co-activators to activate transcription. Here we show that in addition to hormone-independent TR occupancy, ChIP-seq against endogenous TR in mouse liver tissue demonstrates considerable hormone-induced TR recruitment to chromatin associated with chromatin remodelling and activated gene transcription. Genome-wide footprinting analysis using DNase-seq provides little evidence for TR footprints both in the absence and presence of hormone, suggesting that unliganded TR engagement with repressive complexes on chromatin is, similar to activating receptor complexes, a highly dynamic process. This dynamic and ligand-dependent interaction with chromatin is likely shared by all steroid hormone receptors regardless of their capacity to repress transcription in the absence of ligand.

  9. Regulation of gene expression by manipulating transcriptional repressor activity using a novel CoSRI technology.

    Xu, Yue; Li, Song Feng; Parish, Roger W

    2017-07-01

    Targeted gene manipulation is a central strategy for studying gene function and identifying related biological processes. However, a methodology for manipulating the regulatory motifs of transcription factors is lacking as these factors commonly possess multiple motifs (e.g. repression and activation motifs) which collaborate with each other to regulate multiple biological processes. We describe a novel approach designated conserved sequence-guided repressor inhibition (CoSRI) that can specifically reduce or abolish the repressive activities of transcription factors in vivo. The technology was evaluated using the chimeric MYB80-EAR transcription factor and subsequently the endogenous WUS transcription factor. The technology was employed to develop a reversible male sterility system applicable to hybrid seed production. In order to determine the capacity of the technology to regulate the activity of endogenous transcription factors, the WUS repressor was chosen. The WUS repression motif could be inhibited in vivo and the transformed plants exhibited the wus-1 phenotype. Consequently, the technology can be used to manipulate the activities of transcriptional repressor motifs regulating beneficial traits in crop plants and other eukaryotic organisms. © 2016 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  10. Transcription control and neuronal differentiation by agents that activate the LXR nuclear receptor family.

    Schmidt, A; Vogel, R; Holloway, M K; Rutledge, S J; Friedman, O; Yang, Z; Rodan, G A; Friedman, E

    1999-09-10

    LXR and PPAR receptors belong to the nuclear receptor superfamily of transcriptional activating factors. Using ligand-dependent transcription assays, we found that 5-tetradecyloxy-2-furancarboxylic acid (TOFA) transactivates chimeric receptors composed of the glucocorticoid receptor DNA binding domain and the ligand binding regions of PPARalpha, PPARbeta (NUC-1) and LXRbeta (NER) receptors. In the same assays, ligands for PPARs (oleic acid, WY-14643 and L-631,033) and LXRs (hydroxycholesterols) maintain their respective receptor selectivity. TOFA and hydroxycholesterols also stimulate transcription from a minimal fibrinogen promoter that is under the control of AP-1 or NF-kappaB transcription factor binding sites. In addition to their effects on transcription, these LXRbeta activators induce neuronal differentiation in rat pheochromocytoma cells. TOFA and the natural LXR agonist, 22 (R)-hydroxycholesterol, stimulate neurite outgrowth in 55 and 28% of cells, respectively. No neurite outgrowth was induced by the related 22(S)-hydroxycholesterol, which does not activate the LXR family. These results suggest that the hydroxycholesterol signaling pathway has a complex effect on transcription that mediates the activity of TOFA and hydroxycholesterol on neuronal differentiation in pheochromocytoma cells.

  11. Acetylshikonin Inhibits Human Pancreatic PANC-1 Cancer Cell Proliferation by Suppressing the NF-κB Activity.

    Cho, Seok-Cheol; Choi, Bu Young

    2015-09-01

    Acetylshikonin, a natural naphthoquinone derivative compound, has been used for treatment of inflammation and cancer. In the present study, we have investigated whether acetylshikonin could regulate the NF-κB signaling pathway, thereby leading to suppression of tumorigenesis. We observed that acetylshikonin significantly reduced proliferation of several cancer cell lines, including human pancreatic PANC-1 cancer cells. In addition, acetylshikonin inhibited phorbol 12-myristate 13-acetate (PMA) or tumor necrosis-α (TNF-α)-induced NF-κB reporter activity. Proteome cytokine array and real-time RT-PCR results illustrated that acetylshikonin inhibition of PMA-induced production of cytokines was mediated at the transcriptional level and it was associated with suppression of NF-κB activity and matrix metalloprotenases. Finally, we observed that an exposure of acetylshikonin significantly inhibited the anchorage-independent growth of PANC-1 cells. Together, our results indicate that acetylshikonin could serve as a promising therapeutic agent for future treatment of pancreatic cancer.

  12. Design, Engineering, and Characterization of Prokaryotic Ligand-Binding Transcriptional Activators as Biosensors in Yeast

    Ambri, Francesca; Snoek, Tim; Skjødt, Mette Louise

    2018-01-01

    process. In the yeast Saccharomyces cerevisiae, implementation of allosterically regulated transcription factors from prokaryotes as metabolite biosensors has proven a valuable strategy to alleviate this screening bottleneck. Here, we present a protocol to select and incorporate prokaryotic...... transcriptional activators as metabolite biosensors in S. cerevisiae. As an example, we outline the engineering and characterization of the LysR-type transcriptional regulator (LTTR) family member BenM from Acetinobacter sp. ADP1 for monitoring accumulation of cis,cis-muconic acid, a bioplast precursor, in yeast...

  13. Targeted HIV-1 Latency Reversal Using CRISPR/Cas9-Derived Transcriptional Activator Systems.

    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.

  14. miR-17-5p targets the p300/CBP-associated factor and modulates androgen receptor transcriptional activity in cultured prostate cancer cells

    Gong, Ai-Yu; Eischeid, Alex N; Xiao, Jing; Zhao, Jian; Chen, Dongqing; Wang, Zhao-Yi; Young, Charles YF; Chen, Xian-Ming

    2012-01-01

    Androgen receptor (AR) signalling is critical to the initiation and progression of prostate cancer (PCa). Transcriptional activity of AR involves chromatin recruitment of co-activators, including the p300/CBP-associated factor (PCAF). Distinct miRNA expression profiles have been identified in PCa cells during the development and progression of the disease. Whether miRNAs regulate PCAF expression in PCa cells to regulate AR transcriptional activity is still unclear. Expression of PCAF was investigated in several PCa cell lines by qRT-PCR, Western blot, and immunocytochemistry. The effects of PCAF expression on AR-regulated transcriptional activity and cell growth in PCa cells were determined by chromatin immunoprecipitation, reporter gene construct analysis, and MTS assay. Targeting of PCAF by miR-17-5p was evaluated using the luciferase reporter assay. PCAF was upregulated in several PCa cell lines. Upregulation of PCAF promoted AR transcriptional activation and cell growth in cultured PCa cells. Expression of PCAF in PCa cells was associated with the downregulation of miR-17-5p. Targeting of the 3’-untranslated region of PCAF mRNA by miR-17-5p caused translational suppression and RNA degradation, and, consequently, modulation of AR transcriptional activity in PCa cells. PCAF is upregulated in cultured PCa cells, and upregulation of PCAF is associated with the downregulation of miR-17-5p. Targeting of PCAF by miR-17-5p modulates AR transcriptional activity and cell growth in cultured PCa cells

  15. Deciphering the role of the signal- and Sty1 kinase-dependent phosphorylation of the stress-responsive transcription factor Atf1 on gene activation.

    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.

  16. Curcumin Modulates the Radiosensitivity of Colorectal Cancer Cells by Suppressing Constitutive and Inducible NF-κB Activity

    Sandur, Santosh K.; Deorukhkar, Amit; Pandey, Manoj K.; Pabon, Ana Maria B.S.; Shentu, Shujun; Guha, Sushovan; Aggarwal, Bharat B.; Krishnan, Sunil

    2009-01-01

    Purpose: Radiation therapy is an integral part of the preoperative treatment of rectal cancers. However, only a minority of patients achieve a complete pathologic response to therapy because of resistance of these tumors to radiation therapy. This resistance may be mediated by constitutively active pro-survival signaling pathways or by inducible/acquired mechanisms in response to radiation therapy. Simultaneous inhibition of these pathways can sensitize these tumors to radiation therapy. Methods and Materials: Human colorectal cancer cells were exposed to clinically relevant doses of gamma rays, and the mechanism of their radioresistance was investigated. We characterized the transcription factor nuclear factor-κB (NF-κB) activation as a mechanism of inducible radioresistance in colorectal cancer and used curcumin, the active ingredient in the yellow spice turmeric, to overcome this resistance. Results: Curcumin inhibited the proliferation and the post-irradiation clonogenic survival of multiple colorectal cancer cell lines. Radiation stimulated NF-κB activity in a dose- and time-dependent manner, whereas curcumin suppressed this radiation-induced NF-κB activation via inhibition of radiation-induced phosphorylation and degradation of inhibitor of κB alpha, inhibition of inhibitor of κB kinase activity, and inhibition of Akt phosphorylation. Curcumin also suppressed NF-κB-regulated gene products (Bcl-2, Bcl-x L , inhibitor of apoptosis protein-2, cyclooxygenase-2, and cyclin D1). Conclusions: Our results suggest that transient inducible NF-κB activation provides a prosurvival response to radiation that may account for development of radioresistance. Curcumin blocks this signaling pathway and potentiates the antitumor effects of radiation therapy.

  17. Requirement of Hsp105 in CoCl{sub 2}-induced HIF-1α accumulation and transcriptional activation

    Mikami, Hiroki; Saito, Youhei, E-mail: ysaito@mb.kyoto-phu.ac.jp; Okamoto, Namiko; Kakihana, Ayana; Kuga, Takahisa; Nakayama, Yuji, E-mail: nakayama@mb.kyoto-phu.ac.jp

    2017-03-15

    The mammalian stress protein Hsp105α protects cells from stress conditions. Several studies have indicated that Hsp105α is overexpressed in many types of solid tumors, which contain hypoxic microenvironments. However, the role of Hsp105α in hypoxic tumors remains largely unknown. We herein demonstrated the involvement of Hsp105α in HIF-1 functions induced by the hypoxia-mimetic agent CoCl{sub 2}. While Hsp105α is mainly localized in the cytoplasm under normal conditions, a treatment with CoCl{sub 2} induces the nuclear localization of Hsp105α, which correlated with HIF-1α expression levels. The overexpression of degradation-resistant HIF-1α enhances the nuclear localization of Hsp105α without the CoCl{sub 2} treatment. The CoCl{sub 2}-dependent transcriptional activation of HIF-1, which is measured using a reporter gene containing a HIF-responsive element, is reduced by the knockdown of Hsp105α. Furthermore, the CoCl{sub 2}-induced accumulation of HIF-1α is enhanced by heat shock, which results in the nuclear localization of Hsp105, and is suppressed by the knockdown of Hsp105. Hsp105 associates with HIF-1α in CoCl{sub 2}-treated cells. These results suggest that Hsp105α plays an important role in the functions of HIF-1 under hypoxic conditions, in which Hsp105α enhances the accumulation and transcriptional activity of HIF-1 through the HIF-1α-mediated nuclear localization of Hsp105α. - Highlights: • Hsp105α is required for the CoCl{sub 2}-induced transcriptional activation and accumulation of HIF-1. • Hsp105α localizes to the nucleus and interacts with HIF-1α in CoCl{sub 2}-treated cells. • Hsp105 enhances the CoCl{sub 2}-induced accumulation of HIF-1α under heat shock conditions.

  18. Replicative Stress Induces Intragenic Transcription of the ASE1 Gene that Negatively Regulates Ase1 Activity

    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 ...

  19. DNA supercoiling: changes during cellular differentiation and activation of chromatin transcription

    Luchnik, A.N.; Bakayev, V.V.; Glaser, V.M.; Moscow State Univ., USSR)

    1983-01-01

    In this paper it is reported that elastic DNA torsional tension has been observed in a fraction of isolated SV40 minichromosomes, which are shown to be transcriptionally active, and that the number of DNA topological (titratable superhelical) turns in closed superhelical loops of nuclear DNA decreases during cellular differentiation, which, we propose, may be responsible for the coordinate switch in transcription of genes controlling cellular proliferation. 37 references, 6 figures, 2 tables

  20. Constitutively active RAS signaling reduces 1,25 dihydroxyvitamin D-mediated gene transcription in intestinal epithelial cells by reducing vitamin D receptor expression.

    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.

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

    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

  2. The Transcription Factor STAT6 Mediates Direct Repression of Inflammatory Enhancers and Limits Activation of Alternatively Polarized Macrophages

    Czimmerer, Zsolt; Daniel, Bence; Horvath, Attila; Rückerl, Dominik; Nagy, Gergely; Kiss, Mate; Peloquin, Matthew; Budai, Marietta M.; Cuaranta-Monroy, Ixchelt; Simandi, Zoltan; Steiner, Laszlo; Nagy, Bela; Poliska, Szilard; Banko, Csaba; Bacso, Zsolt

    2018-01-01

    Summary The molecular basis of signal-dependent transcriptional activation has been extensively studied in macrophage polarization, but our understanding remains limited regarding the molecular determinants of repression. Here we show that IL-4-activated STAT6 transcription factor is required for the direct transcriptional repression of a large number of genes during in vitro and in vivo alternative macrophage polarization. Repression results in decreased lineage-determining transcription fac...

  3. Novel isoforms of the TFIID subunit TAF4 modulate nuclear receptor-mediated transcriptional activity

    Brunkhorst, Adrian; Neuman, Toomas; Hall, Anita; Arenas, Ernest; Bartfai, Tamas; Hermanson, Ola; Metsis, Madis

    2004-01-01

    The transcription factor TFIID consists of TATA-binding protein (TBP) and TBP-associated factors (TAFs). TAFs are essential for modulation of transcriptional activity but the regulation of TAFs is complex and many important aspects remain unclear. In this study, we have identified and characterized five novel truncated forms of the TFIID subunit TAF4 (TAF II 135). Analysis of the mouse gene structure revealed that all truncations were the results of alternative splicing and resulted in the loss of domains or parts of domains implicated in TAF4 functional interactions. Results from transcriptional assays showed that several of the TAF4 isoforms exerted dominant negative effects on TAF4 activity in nuclear receptor-mediated transcriptional activation. In addition, alternative TAF4 isoforms could be detected in specific cell types. Our results indicate an additional level of complexity in TAF4-mediated regulation of transcription and suggest context-specific roles for these new TAF4 isoforms in transcriptional regulation in vivo

  4. THRAP3 interacts with and inhibits the transcriptional activity of SOX9 during chondrogenesis.

    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.

  5. Physiological and Pathological Transcriptional Activation of Endogenous Retroelements Assessed by RNA-Sequencing of B Lymphocytes

    Jan Attig

    2017-12-01

    Full Text Available In addition to evolutionarily-accrued sequence mutation or deletion, endogenous retroelements (EREs in eukaryotic genomes are subject to epigenetic silencing, preventing or reducing their transcription, particularly in the germplasm. Nevertheless, transcriptional activation of EREs, including endogenous retroviruses (ERVs and long interspersed nuclear elements (LINEs, is observed in somatic cells, variably upon cellular differentiation and frequently upon cellular transformation. ERE transcription is modulated during physiological and pathological immune cell activation, as well as in immune cell cancers. However, our understanding of the potential consequences of such modulation remains incomplete, partly due to the relative scarcity of information regarding genome-wide ERE transcriptional patterns in immune cells. Here, we describe a methodology that allows probing RNA-sequencing (RNA-seq data for genome-wide expression of EREs in murine and human cells. Our analysis of B cells reveals that their transcriptional response during immune activation is dominated by induction of gene transcription, and that EREs respond to a much lesser extent. The transcriptional activity of the majority of EREs is either unaffected or reduced by B cell activation both in mice and humans, albeit LINEs appear considerably more responsive in the latter host. Nevertheless, a small number of highly distinct ERVs are strongly and consistently induced during B cell activation. Importantly, this pattern contrasts starkly with B cell transformation, which exhibits widespread induction of EREs, including ERVs that minimally overlap with those responsive to immune stimulation. The distinctive patterns of ERE induction suggest different underlying mechanisms and will help separate physiological from pathological expression.

  6. The Small Protein HemP Is a Transcriptional Activator for the Hemin Uptake Operon in Burkholderia multivorans ATCC 17616.

    Sato, Takuya; Nonoyama, Shouta; Kimura, Akane; Nagata, Yuji; Ohtsubo, Yoshiyuki; Tsuda, Masataka

    2017-08-15

    Iron and heme play very important roles in various metabolic functions in bacteria, and their intracellular homeostasis is maintained because high concentrations of free forms of these molecules greatly facilitate the Fenton reaction-mediated production of large amounts of reactive oxygen species that severely damage various biomolecules. The ferric uptake regulator (Fur) from Burkholderia multivorans ATCC 17616 is an iron-responsive global transcriptional regulator, and its fur deletant exhibits pleiotropic phenotypes. In this study, we found that the phenotypes of the fur deletant were suppressed by an additional mutation in hemP The transcription of hemP was negatively regulated by Fur under iron-replete conditions and was constitutive in the fur deletant. Growth of a hemP deletant was severely impaired in a medium containing hemin as the sole iron source, demonstrating the important role of HemP in hemin utilization. HemP was required as a transcriptional activator that specifically binds the promoter-containing region upstream of a Fur-repressive hmuRSTUV operon, which encodes the proteins for hemin uptake. A hmuR deletant was still able to grow using hemin as the sole iron source, albeit at a rate clearly lower than that of the wild-type strain. These results strongly suggested (i) the involvement of HmuR in hemin uptake and (ii) the presence in ATCC 17616 of at least part of other unknown hemin uptake systems whose expression depends on the HemP function. Our in vitro analysis also indicated high-affinity binding of HemP to hemin, and such a property might modulate transcriptional activation of the hmu operon. IMPORTANCE Although the hmuRSTUV genes for the utilization of hemin as a sole iron source have been identified in a few Burkholderia strains, the regulatory expression of these genes has remained unknown. Our analysis in this study using B. multivorans ATCC 17616 showed that its HemP protein is required for expression of the hmuRSTUV operon, and the

  7. A compendium of transcription factor and Transcriptionally active protein coding gene families in cowpea (Vigna unguiculata L.).

    Misra, Vikram A; Wang, Yu; Timko, Michael P

    2017-11-22

    Cowpea (Vigna unguiculata (L.) Walp.) is the most important food and forage legume in the semi-arid tropics of sub-Saharan Africa where approximately 80% of worldwide production takes place primarily on low-input, subsistence farm sites. Among the major goals of cowpea breeding and improvement programs are the rapid manipulation of agronomic traits for seed size and quality and improved resistance to abiotic and biotic stresses to enhance productivity. Knowing the suite of transcription factors (TFs) and transcriptionally active proteins (TAPs) that control various critical plant cellular processes would contribute tremendously to these improvement aims. We used a computational approach that employed three different predictive pipelines to data mine the cowpea genome and identified over 4400 genes representing 136 different TF and TAP families. We compare the information content of cowpea to two evolutionarily close species common bean (Phaseolus vulgaris), and soybean (Glycine max) to gauge the relative informational content. Our data indicate that correcting for genome size cowpea has fewer TF and TAP genes than common bean (4408 / 5291) and soybean (4408/ 11,065). Members of the GROWTH-REGULATING FACTOR (GRF) and Auxin/indole-3-acetic acid (Aux/IAA) gene families appear to be over-represented in the genome relative to common bean and soybean, whereas members of the MADS (Minichromosome maintenance deficient 1 (MCM1), AGAMOUS, DEFICIENS, and serum response factor (SRF)) and C2C2-YABBY appear to be under-represented. Analysis of the AP2-EREBP APETALA2-Ethylene Responsive Element Binding Protein (AP2-EREBP), NAC (NAM (no apical meristem), ATAF1, 2 (Arabidopsis transcription activation factor), CUC (cup-shaped cotyledon)), and WRKY families, known to be important in defense signaling, revealed changes and phylogenetic rearrangements relative to common bean and soybean that suggest these groups may have evolved different functions. The availability of detailed

  8. Tat-dependent repression of human immunodeficiency virus type 1 long terminal repeat promoter activity by fusion of cellular transcription factors

    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

  9. The interpretation of mu suppression as an index of mirror neuron activity: past, present and future.

    Hobson, Hannah M; Bishop, Dorothy V M

    2017-03-01

    Mu suppression studies have been widely used to infer the activity of the human mirror neuron system (MNS) in a number of processes, ranging from action understanding, language, empathy and the development of autism spectrum disorders (ASDs). Although mu suppression is enjoying a resurgence of interest, it has a long history. This review aimed to revisit mu's past, and examine its recent use to investigate MNS involvement in language, social processes and ASDs. Mu suppression studies have largely failed to produce robust evidence for the role of the MNS in these domains. Several key potential shortcomings with the use and interpretation of mu suppression, documented in the older literature and highlighted by more recent reports, are explored here.

  10. New Transcriptional Reporters to Quantify and Monitor PPARγ Activity

    Séverine A. Degrelle

    2017-01-01

    Full Text Available The peroxisome-proliferator-activated-receptor-γ (PPARγ is a member of the nuclear receptor superfamily that plays a critical role in diverse biological processes, including adipogenesis, lipid metabolism, and placental development. To study the activity of PPARγ, we constructed two new reporter genes: a fluorescent GFP-tagged histone-2B (PPRE-H2B-eGFP and a secreted nanoluciferase (PPRE-pNL1.3[secNluc]. This study demonstrates their usage to monitor PPARγ activity in different cell types and screen for PPARγ’s potential ligands.

  11. Protein kinase A activation enhances β-catenin transcriptional activity through nuclear localization to PML bodies.

    Mei Zhang

    Full Text Available The Protein Kinase A (PKA and Wnt signaling cascades are fundamental pathways involved in cellular development and maintenance. In the osteoblast lineage, these pathways have been demonstrated functionally to be essential for the production of mineralized bone. Evidence for PKA-Wnt crosstalk has been reported both during tumorigenesis and during organogenesis, and the nature of the interaction is thought to rely on tissue and cell context. In this manuscript, we analyzed bone tumors arising from mice with activated PKA caused by mutation of the PKA regulatory subunit Prkar1a. In primary cells from these tumors, we observed relocalization of β-catenin to intranuclear punctuate structures, which were identified as PML bodies. Cellular redistribution of β-catenin could be recapitulated by pharmacologic activation of PKA. Using 3T3-E1 pre-osteoblasts as a model system, we found that PKA phosphorylation sites on β-catenin were required for nuclear re-localization. Further, β-catenin's transport to the nucleus was accompanied by an increase in canonical Wnt-dependent transcription, which also required the PKA sites. PKA-Wnt crosstalk in the cells was bi-directional, including enhanced interactions between β-catenin and the cAMP-responsive element binding protein (CREB and transcriptional crosstalk between the Wnt and PKA signaling pathways. Increases in canonical Wnt/β-catenin signaling were associated with a decrease in the activity of the non-canonical Wnt/Ror2 pathway, which has been shown to antagonize canonical Wnt signaling. Taken together, this study provides a new understanding of the complex regulation of the subcellular distribution of β-catenin and its differential protein-protein interaction that can be modulated by PKA signaling.

  12. Activated T cells sustain myeloid-derived suppressor cell-mediated immune suppression

    Damuzzo, Vera; Francescato, Samuela; Pozzuoli, Assunta; Berizzi, Antonio; Mocellin, Simone; Rossi, Carlo Riccardo; Bronte, Vincenzo; Mandruzzato, Susanna

    2016-01-01

    The expansion of myeloid derived suppressor cells (MDSCs), a suppressive population able to hamper the immune response against cancer, correlates with tumor progression and overall survival in several cancer types. We have previously shown that MDSCs can be induced in vitro from precursors present in the bone marrow and observed that these cells are able to actively proliferate in the presence of activated T cells, whose activation level is critical to drive the suppressive activity of MDSCs. Here we investigated at molecular level the mechanisms involved in the interplay between MDSCs and activated T cells. We found that activated T cells secrete IL-10 following interaction with MDSCs which, in turn, activates STAT3 phosphorylation on MDSCs then leading to B7-H1 expression. We also demonstrated that B7-H1+ MDSCs are responsible for immune suppression through a mechanism involving ARG-1 and IDO expression. Finally, we show that the expression of ligands B7-H1 and MHC class II both on in vitro-induced MDSCs and on MDSCs in the tumor microenvironment of cancer patients is paralleled by an increased expression of their respective receptors PD-1 and LAG-3 on T cells, two inhibitory molecules associated with T cell dysfunction. These findings highlight key molecules and interactions responsible for the extensive cross-talk between MDSCs and activated T cells that are at the basis of immune suppression. PMID:26700461

  13. Modulating basal ganglia and cerebellar activity to suppress parkinsonian tremor

    Heida, Tjitske; Zhao, Yan; van Wezel, Richard Jack Anton

    2013-01-01

    Despite extensive research, the detailed pathophysiology of the parkinsonian tremor is still unknown. It has been hypothesized that the generation of parkinsonian tremor is related to abnormal activity within the basal ganglia. The cerebello-thalamic-cortical loop has been suggested to indirectly

  14. Histone deacetylase inhibitors suppress immune activation in primary mouse microglia

    Kannan, Vishnu; Brouwer, Nieske; Hanisch, Uwe-Karsten; Regen, Tommy; Eggen, Bart J. L.; Boddeke, Hendrikus W. G. M.

    Neuroinflammation is required for tissue clearance and repair after infections or insults. To prevent excessive damage, it is crucial to limit the extent of neuroinflammation and thereby the activation of its principal effector cell, microglia. The two main major innate immune cell types in the CNS

  15. Cdk1 activity acts as a quantitative platform for coordinating cell cycle progression with periodic transcription

    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

  16. Redefining the transcriptional regulatory dynamics of classically and alternatively activated macrophages by deepCAGE transcriptomics

    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.

  17. The Brakeless co-regulator can directly activate and repress transcription in early Drosophila embryos.

    Crona, Filip; Holmqvist, Per-Henrik; Tang, Min; Singla, Bhumica; Vakifahmetoglu-Norberg, Helin; Fantur, Katrin; Mannervik, Mattias

    2015-11-01

    The Brakeless protein performs many important functions during Drosophila development, but how it controls gene expression is poorly understood. We previously showed that Brakeless can function as a transcriptional co-repressor. In this work, we perform transcriptional profiling of brakeless mutant embryos. Unexpectedly, the majority of affected genes are down-regulated in brakeless mutants. We demonstrate that genomic regions in close proximity to some of these genes are occupied by Brakeless, that over-expression of Brakeless causes a reciprocal effect on expression of these genes, and that Brakeless remains an activator of the genes upon fusion to an activation domain. Together, our results show that Brakeless can both repress and activate gene expression. A yeast two-hybrid screen identified the Mediator complex subunit Med19 as interacting with an evolutionarily conserved part of Brakeless. Both down- and up-regulated Brakeless target genes are also affected in Med19-depleted embryos, but only down-regulated targets are influenced in embryos depleted of both Brakeless and Med19. Our data provide support for a Brakeless activator function that regulates transcription by interacting with Med19. We conclude that the transcriptional co-regulator Brakeless can either activate or repress transcription depending on context. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Design, Assembly, and Characterization of TALE-Based Transcriptional Activators and Repressors.

    Thakore, Pratiksha I; Gersbach, Charles A

    2016-01-01

    Transcription activator-like effectors (TALEs) are modular DNA-binding proteins that can be fused to a variety of effector domains to regulate the epigenome. Nucleotide recognition by TALE monomers follows a simple cipher, making this a powerful and versatile method to activate or repress gene expression. Described here are methods to design, assemble, and test TALE transcription factors (TALE-TFs) for control of endogenous gene expression. In this protocol, TALE arrays are constructed by Golden Gate cloning and tested for activity by transfection and quantitative RT-PCR. These methods for engineering TALE-TFs are useful for studies in reverse genetics and genomics, synthetic biology, and gene therapy.

  19. Virulent Type A Francisella tularensis actively suppresses cytokine responses in human monocytes

    Gillette, Devyn D.; Curry, Heather M.; Cremer, Thomas; Ravneberg, David; Fatehchand, Kavin; Shah, Prexy A.; Wewers, Mark D.; Schlesinger, Larry S.; Butchar, Jonathan P.; Tridandapani, Susheela; Gavrilin, Mikhail A.

    2014-01-01

    Background: Human monocyte inflammatory responses differ between virulent and attenuated Francisella infection. Results: A mixed infection model showed that the virulent F. tularensis Schu S4 can attenuate inflammatory cytokine responses to the less virulent F. novicida in human monocytes. Conclusion: F. tularensis dampens inflammatory response by an active process. Significance: This suppression may contribute to enhanced pathogenicity of F. tularensis. Francisella tularensis is a Gram-negative facultative bacterium that can cause the disease tularemia, even upon exposure to low numbers of bacteria. One critical characteristic of Francisella is its ability to dampen or subvert the host immune response. Previous work has shown that monocytes infected with highly virulent F. tularensis subsp. tularensis strain Schu S4 responded with a general pattern of quantitatively reduced pro-inflammatory signaling pathway genes and cytokine production in comparison to those infected with the less virulent related F. novicida. However, it has been unclear whether the virulent Schu S4 was merely evading or actively suppressing monocyte responses. By using mixed infection assays with F. tularensis and F. novicida, we show that F. tularensis actively suppresses monocyte pro-inflammatory responses. Additional experiments show that this suppression occurs in a dose-dependent manner and is dependent upon the viability of F. tularensis. Importantly, F. tularensis was able to suppress pro-inflammatory responses to earlier infections with F. novicida. These results lend support that F. tularensis actively dampens human monocyte responses and this likely contributes to its enhanced pathogenicity. PMID:24783062

  20. Eviction of linker histone H1 by NAP-family histone chaperones enhances activated transcription.

    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

  1. Primate-specific microRNA-637 inhibits tumorigenesis in hepatocellular carcinoma by disrupting signal transducer and activator of transcription 3 signaling.

    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.

  2. CpG methylation suppresses transcriptional activity of human syncytin-1 in non-placental tissues

    Matoušková, Magda; Blažková, Jana; Pajer, Petr; Pavlíček, Adam; Hejnar, Jiří

    2006-01-01

    Roč. 312, č. 7 (2006), s. 1011-1020 ISSN 0014-4827 R&D Projects: GA ČR(CZ) GA204/05/0939; GA AV ČR(CZ) IAA5052207 Institutional research plan: CEZ:AV0Z50520514 Keywords : syncytin-1 * trophoblast * DNA methylation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.777, year: 2006

  3. Rational Design of Mini-Cas9 for Transcriptional Activation.

    Ma, Dacheng; Peng, Shuguang; Huang, Weiren; Cai, Zhiming; Xie, Zhen

    2018-04-20

    Nuclease dead Cas9 (dCas9) has been widely used for modulating gene expression by fusing with different activation or repression domains. However, delivery of the CRISPR/Cas system fused with various effector domains in a single adeno-associated virus (AAV) remains challenging due to the payload limit. Here, we engineered a set of downsized variants of Cas9 including Staphylococcus aureus Cas9 (SaCas9) that retained DNA binding activity by deleting conserved functional domains. We demonstrated that fusing FokI nuclease domain to the N-terminal of the minimal SaCas9 (mini-SaCas9) or to the middle of the split mini-SaCas9 can trigger efficient DNA cleavage. In addition, we constructed a set of compact transactivation domains based on the tripartite VPR activation domain and self-assembled arrays of split SpyTag:SpyCatch peptides, which are suitable for fusing to the mini-SaCas9. Lastly, we produced a single AAV containing the mini-SaCas9 fused with a downsized transactivation domain along with an optimized gRNA expression cassette, which showed efficient transactivation activity. Our results highlighted a practical approach to generate down-sized CRISPR/Cas9 and gene activation systems for in vivo applications.

  4. Regulation of the yeast metabolic cycle by transcription factors with periodic activities

    Pellegrini Matteo

    2011-10-01

    Full Text Available Abstract Background When growing budding yeast under continuous, nutrient-limited conditions, over half of yeast genes exhibit periodic expression patterns. Periodicity can also be observed in respiration, in the timing of cell division, as well as in various metabolite levels. Knowing the transcription factors involved in the yeast metabolic cycle is helpful for determining the cascade of regulatory events that cause these patterns. Results Transcription factor activities were estimated by linear regression using time series and genome-wide transcription factor binding data. Time-translation matrices were estimated using least squares and were used to model the interactions between the most significant transcription factors. The top transcription factors have functions involving respiration, cell cycle events, amino acid metabolism and glycolysis. Key regulators of transitions between phases of the yeast metabolic cycle appear to be Hap1, Hap4, Gcn4, Msn4, Swi6 and Adr1. Conclusions Analysis of the phases at which transcription factor activities peak supports previous findings suggesting that the various cellular functions occur during specific phases of the yeast metabolic cycle.

  5. Ginsenoside Compound K suppresses the hepatic gluconeogenesis via activating adenosine-5'monophosphate kinase: A study in vitro and in vivo.

    Wei, Shengnan; Li, Wei; Yu, Yang; Yao, Fan; A, Lixiang; Lan, Xiaoxin; Guan, Fengying; Zhang, Ming; Chen, Li

    2015-10-15

    Compound K (CK) is a final intestinal metabolite of protopanaxadiol-type ginsenoside. We have reported that CK presented anti-diabetic effect via diminishing the expressions of hepatic gluconeogenesis key enzyme. Here, we further explore the possible mechanism of CK on suppression hepatic gluconeogenesis via activation of adenosine-5'monophosphate kinase (AMPK) on type 2 diabetes mice in vivo and in HepG2 cells. Type 2 diabetes mice model was developed by high fat diet combined with STZ injection. 30mg/kg/d CK was orally administrated for 4weeks, the fasting blood glucose level and 2h OGTT were conducted, and the protein expression of AMPK, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), Phosphoenolpyruvate carboxykinase (PEPCK) and Glucose-6-phosphatase (G6Pase) were examined. The mechanism of Compound K on hepatic gluconeogenesis was further explored in HepG2 hepatocytes. Glucose production, the protein expression of AMPK, PEPCK, G6pase and PGC-1α, hepatic nuclear factor 4α (HNF-4α) and forkhead transcription factor O1 (FOXO1) were determined after Compound K treatment at the presence of AMPK inhibitor Compound C. We observed that CK inhibited the expression of PEPCK and G6Pase in the liver and in HepG2 hepatocytes. Meanwhile, CK treatment remarkably increased the activation of AMPK, while decreasing the expressions of PGC-1α, HNF-4α and FOXO1. However, AMPK inhibitor Compound C could reverse these effects of CK on gluconeogenesis in part. The results indicated that the effect of CK on suppression hepatic gluconeogenesis might be via the activation the AMPK activity. Copyright © 2015. Published by Elsevier Inc.

  6. Development of Active Flutter Suppression Wind Tunnel Testing Technology

    1975-01-01

    inch stainless steel precision haft ng out to the aileron surfaces. Torque was then transmitted aft through another crank-pushrod linkage...NMMltetiM Clllir llllisi Sl> ptT »I»" CmrN StiiiH tli!ii<ti> »ir|wu ŗK kUfej •*! AFFDL-TR-74-126 o 00 DEVELOPMENT OF ACTIVE FLUTTER...Installations . . 28 14. Outboard Aileron Installation 30 15. Airplane FMCS Block Diagram 35 16. Model FMCS Block Diagram 36 17. Model FMCS

  7. WRKY transcription factors involved in activation of SA biosynthesis genes

    van Verk, Marcel C; Bol, John F; Linthorst, Huub J M

    2011-01-01

    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

  8. Expression and Activation of STAT Transcription Factors in Breast Cancer

    1998-05-08

    clinicians. J~, 273: 577-585, 1995. 183 Hundertmark 5, Buhler H, Rudolf M, Weitzel HK, Ragosch V: Inhibition of 11 beta-hydroxysteroid dehydrogenase...activated protein kinase through a Jakl-dependent pathway. Mol. Cell. Bioi., 17:3833-40, 1997. Stewart JF, Rubens RO, King RJ, Minton MJ, Steiner R

  9. MAML1 enhances the transcriptional activity of Runx2 and plays a role in bone development.

    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.

  10. Neuronal activity-regulated gene transcription: how are distant synaptic signals conveyed to the nucleus?

    Matamales, Miriam

    2012-12-19

    Synaptic activity can trigger gene expression programs that are required for the stable change of neuronal properties, a process that is essential for learning and memory. Currently, it is still unclear how the stimulation of dendritic synapses can be coupled to transcription in the nucleus in a timely way given that large distances can separate these two cellular compartments. Although several mechanisms have been proposed to explain long distance communication between synapses and the nucleus, the possible co-existence of these models and their relevance in physiological conditions remain elusive. One model suggests that synaptic activation triggers the translocation to the nucleus of certain transcription regulators localised at postsynaptic sites that function as synapto-nuclear messengers. Alternatively, it has been hypothesised that synaptic activity initiates propagating regenerative intracellular calcium waves that spread through dendrites into the nucleus where nuclear transcription machinery is thereby regulated. It has also been postulated that membrane depolarisation of voltage-gated calcium channels on the somatic membrane is sufficient to increase intracellular calcium concentration and activate transcription without the need for transported signals from distant synapses. Here I provide a critical overview of the suggested mechanisms for coupling synaptic stimulation to transcription, the underlying assumptions behind them and their plausible physiological significance.

  11. Mechanism of suppression of normal hemopoietic activity by lymphokine-activated killer cells and their products

    Gibson, F.M.; Malkovska, V.; Myint, A.A.; Meager, A.; Gordon-Smith, E.C.

    1991-01-01

    Interleukin 2 (IL-2)-activated lymphocytes (lymphokine-activated killer [LAK] cells) have been shown to inhibit the formation of autologous human granulocyte-macrophage hemopoietic progenitors (granulocyte-macrophage colony-forming units, CFU-GM) in vitro. Effects of LAK cells on these progenitors may include a number of different mechanisms. LAK cells are potent cytotoxic lymphocytes capable of lysing certain normal autologous cells. They also produce cytokines known to inhibit hemopoiesis (interferon gamma [IFN-gamma] and tumor necrosis factor alpha [TNF-alpha]) or enhance it (granulocyte-macrophage colony-stimulating factor, GM-CSF). In the authors' current study they analyzed the mechanism of suppression of autologous CFU-GM by LAK cells. Their results suggest that LAK cells are not directly cytotoxic to normal CFU-GM. They show that it is possible to abolish the hemopoiesis-inhibiting activity of LAK cells without abrogating their cytotoxicity against tumor cell lines using inhibitors of DNA synthesis, namely hydroxyurea or irradiation

  12. How to inhibit a distractor location? Statistical learning versus active, top-down suppression.

    Wang, Benchi; Theeuwes, Jan

    2018-05-01

    Recently, Wang and Theeuwes (Journal of Experimental Psychology: Human Perception and Performance, 44(1), 13-17, 2018a) demonstrated the role of lingering selection biases in an additional singleton search task in which the distractor singleton appeared much more often in one location than in all other locations. For this location, there was less capture and selection efficiency was reduced. It was argued that statistical learning induces plasticity within the spatial priority map such that particular locations that are high likely to contain a distractor are suppressed relative to all other locations. The current study replicated these findings regarding statistical learning (Experiment 1) and investigated whether similar effects can be obtained by cueing the distractor location in a top-down way on a trial-by-trial basis. The results show that top-down cueing of the distractor location with long (1,500 ms; Experiment 2) and short stimulus-onset symmetries (SOAs) (600 ms; Experiment 3) does not result in suppression: The amount of capture nor the efficiency of selection was affected by the cue. If anything, we found an attentional benefit (instead of the suppression) for the short SOA. We argue that through statistical learning, weights within the attentional priority map are changed such that one location containing a salient distractor is suppressed relative to all other locations. Our cueing experiments show that this effect cannot be accomplished by active, top-down suppression. Consequences for recent theories of distractor suppression are discussed.

  13. Buddleja officinalis suppresses high glucose-induced vascular smooth muscle cell proliferation: role of mitogen-activated protein kinases, nuclear factor-kappaB and matrix metalloproteinases.

    Lee, Yun Jung; Kim, Jin Sook; Kang, Dae Gill; Lee, Ho Sub

    2010-02-01

    Diabetes mellitus is a well-established risk factor for vascular diseases caused by atherosclerosis. In the development of diabetic atherogenesis, vascular smooth muscle cell proliferation is recognized as a key event. Thus, we aimed to investigate whether an ethanol extract of Buddleja officinalis (EBO) suppresses high glucose-induced proliferation in primary cultured human aortic smooth muscle cells (HASMC). [(3)H]-thymidine incorporation revealed that incubation of HASMC with a high concentration of glucose (25 mmol/L) increased cell proliferation. The expression levels of cell cycle protein were also increased by treatment with high glucose concentration. Pretreatment of HASMC with EBO significantly attenuated the increase of high glucose-induced cell proliferation as well as p38 mitogen-activated protein kinases (MAPK) and JNK phosphorylation. EBO suppressed high glucose-induced matrix metalloproteinase (MMP)-9 activity in a dose-dependent manner. In addition, EBO suppressed nuclear factor-kappaB (NF-kappaB) nuclear translocation and transcriptional activity in high glucose conditions. Taken together, the present data suggest that EBO could suppress high glucose-induced atherosclerotic processes through inhibition of p38, JNK, NF-kappaB and MMP signal pathways in HASMC.

  14. Palmitoylation regulates 17β-estradiol-induced estrogen receptor-α degradation and transcriptional activity.

    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.

  15. PEA3/ETV4-related transcription factors coupled with active ERK signalling are associated with poor prognosis in gastric adenocarcinoma

    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\

  16. Suppression of leukocyte inhibitory factor (LIF) production and [3H]thymidine incorporation by concanavalin A-activated mononuclear cells

    Lomnitzer, R.; Rabson, A.R.

    1979-01-01

    The capacity of human mononuclear (MN) cells pretreated with concanavalin A (Con A) to suppress the activity of fresh phytohemagglutinin (PHA)-pulsed mononuclear cells was assessed. Con A-pretreated MN cells suppressed leukocyte inhibitory factor (LIF) activity in supernatants of PHA-pulsed cell cultures and [ 3 H]thymidine incorporation by these cells. Suppression was obtained in both allogeneic and autologous systems with mitomycin-treated, irradiated, or untreated Con A-induced cells. Lymphocytes from two patients that, following treatment with Con A, did not suppress mitogen-induced proliferative response of normal cells also did not suppress LIF production

  17. O-GlcNAc transferase regulates transcriptional activity of human Oct4.

    Constable, Sandii; Lim, Jae-Min; Vaidyanathan, Krithika; Wells, Lance

    2017-10-01

    O-linked β-N-acetylglucosamine (O-GlcNAc) is a single sugar modification found on many different classes of nuclear and cytoplasmic proteins. Addition of this modification, by the enzyme O-linked N-acetylglucosamine transferase (OGT), is dynamic and inducible. One major class of proteins modified by O-GlcNAc is transcription factors. O-GlcNAc regulates transcription factor properties through a variety of different mechanisms including localization, stability and transcriptional activation. Maintenance of embryonic stem (ES) cell pluripotency requires tight regulation of several key transcription factors, many of which are modified by O-GlcNAc. Octamer-binding protein 4 (Oct4) is one of the key transcription factors required for pluripotency of ES cells and more recently, the generation of induced pluripotent stem (iPS) cells. The action of Oct4 is modulated by the addition of several post-translational modifications, including O-GlcNAc. Previous studies in mice found a single site of O-GlcNAc addition responsible for transcriptional regulation. This study was designed to determine if this mechanism is conserved in humans. We mapped 10 novel sites of O-GlcNAc attachment on human Oct4, and confirmed a role for OGT in transcriptional activation of Oct4 at a site distinct from that found in mouse that allows distinction between different Oct4 target promoters. Additionally, we uncovered a potential new role for OGT that does not include its catalytic function. These results confirm that human Oct4 activity is being regulated by OGT by a mechanism that is distinct from mouse Oct4. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Kaempferol modulates pro-inflammatory NF-κB activation by suppressing advanced glycation endproducts-induced NADPH oxidase

    Kim, Ji Min; Lee, Eun Kyeong; Kim, Dae Hyun; Yu, Byung Pal

    2010-01-01

    Advanced glycation endproducts (AGE) are oxidative products formed from the reaction between carbohydrates and a free amino group of proteins that are provoked by reactive species (RS). It is also known that AGE enhance the generation of RS and that the binding of AGE to a specific AGE receptor (RAGE) induces the activation of the redox-sensitive, pro-inflammatory transcription factor, nuclear factor-kappa B (NF-ĸB). In this current study, we investigated the anti-oxidative effects of short-term kaempferol supplementation on the age-related formation of AGE and the binding activity of RAGE in aged rat kidney. We further investigated the suppressive action of kaempferol against AGE's ability to stimulate activation of pro-inflammatory NF-ĸB and its molecular mechanisms. For this study, we utilized young (6 months old), old (24 months old), and kaempferol-fed (2 and 4 mg/kg/day for 10 days) old rats. In addition, for the molecular work, the rat endothelial cell line, YPEN-1 was used. The results show that AGE and RAGE were increased during aging and that these increases were blunted by kaempferol. In addition, dietary kaempferol reduced age-related increases in NF-κB activity and NF-ĸB-dependant pro-inflammatory gene activity. The most significant new finding from this study is that kaempferol supplementation prevented age-related NF-κB activation by suppressing AGE-induced nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase). Taken together, our results demonstrated that dietary kaempferol exerts its anti-oxidative and anti-inflammatory actions by modulating the age-related NF-κB signaling cascade and its pro-inflammatory genes by suppressing AGE-induced NADPH oxidase activation. Based on these data, dietary kaempferol is proposed as a possible anti-AGE agent that may have the potential for use in anti-inflammation therapies. PMID:20431987

  19. Controlling cellular P-TEFb activity by the HIV-1 transcriptional transactivator Tat.

    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.

  20. Negative Correlation between the Diffusion Coefficient and Transcriptional Activity of the Glucocorticoid Receptor.

    Mikuni, Shintaro; Yamamoto, Johtaro; Horio, Takashi; Kinjo, Masataka

    2017-08-25

    The glucocorticoid receptor (GR) is a transcription factor, which interacts with DNA and other cofactors to regulate gene transcription. Binding to other partners in the cell nucleus alters the diffusion properties of GR. Raster image correlation spectroscopy (RICS) was applied to quantitatively characterize the diffusion properties of EGFP labeled human GR (EGFP-hGR) and its mutants in the cell nucleus. RICS is an image correlation technique that evaluates the spatial distribution of the diffusion coefficient as a diffusion map. Interestingly, we observed that the averaged diffusion coefficient of EGFP-hGR strongly and negatively correlated with its transcriptional activities in comparison to that of EGFP-hGR wild type and mutants with various transcriptional activities. This result suggests that the decreasing of the diffusion coefficient of hGR was reflected in the high-affinity binding to DNA. Moreover, the hyper-phosphorylation of hGR can enhance the transcriptional activity by reduction of the interaction between the hGR and the nuclear corepressors.

  1. Alterations in leukocyte transcriptional control pathway activity associated with major depressive disorder and antidepressant treatment.

    Mellon, S H; Wolkowitz, O M; Schonemann, M D; Epel, E S; Rosser, R; Burke, H B; Mahan, L; Reus, V I; Stamatiou, D; Liew, C-C; Cole, S W

    2016-05-24

    Major depressive disorder (MDD) is associated with a significantly elevated risk of developing serious medical illnesses such as cardiovascular disease, immune impairments, infection, dementia and premature death. Previous work has demonstrated immune dysregulation in subjects with MDD. Using genome-wide transcriptional profiling and promoter-based bioinformatic strategies, we assessed leukocyte transcription factor (TF) activity in leukocytes from 20 unmedicated MDD subjects versus 20 age-, sex- and ethnicity-matched healthy controls, before initiation of antidepressant therapy, and in 17 of the MDD subjects after 8 weeks of sertraline treatment. In leukocytes from unmedicated MDD subjects, bioinformatic analysis of transcription control pathway activity indicated an increased transcriptional activity of cAMP response element-binding/activating TF (CREB/ATF) and increased activity of TFs associated with cellular responses to oxidative stress (nuclear factor erythroid-derived 2-like 2, NFE2l2 or NRF2). Eight weeks of antidepressant therapy was associated with significant reductions in Hamilton Depression Rating Scale scores and reduced activity of NRF2, but not in CREB/ATF activity. Several other transcriptional regulation pathways, including the glucocorticoid receptor (GR), nuclear factor kappa-B cells (NF-κB), early growth response proteins 1-4 (EGR1-4) and interferon-responsive TFs, showed either no significant differences as a function of disease or treatment, or activities that were opposite to those previously hypothesized to be involved in the etiology of MDD or effective treatment. Our results suggest that CREB/ATF and NRF2 signaling may contribute to MDD by activating immune cell transcriptome dynamics that ultimately influence central nervous system (CNS) motivational and affective processes via circulating mediators.

  2. G-actin sequestering protein thymosin-β4 regulates the activity of myocardin-related transcription factor.

    Morita, Tsuyoshi; Hayashi, Ken'ichiro

    2013-08-02

    Myocardin-related transcription factors (MRTFs) are robust coactivators of serum response factor (SRF). MRTFs contain three copies of the RPEL motif at their N-terminus, and they bind to monomeric globular actin (G-actin). Previous studies illustrate that G-actin binding inhibits MRTF activity by preventing the MRTFs nuclear accumulation. In the living cells, the majority of G-actin is sequestered by G-actin binding proteins that prevent spontaneous actin polymerization. Here, we demonstrate that the most abundant G-actin sequestering protein thymosin-β4 (Tβ4) was involved in the regulation of subcellular localization and activity of MRTF-A. Tβ4 competed with MRTF-A for G-actin binding; thus, interfering with G-actin-MRTF-A complex formation. Tβ4 overexpression induced the MRTF-A nuclear accumulation and activation of MRTF-SRF signaling. The activation rate of MRTF-A by the Tβ4 mutant L17A, whose affinity for G-actin is very low, was lower than that by wild-type Tβ4. In contrast, the β-actin mutant 3DA, which has a lower affinity for Tβ4, more effectively suppressed MRTF-A activity than wild-type β-actin. Furthermore, ectopic Tβ4 increased the endogenous expression of SRF-dependent actin cytoskeletal genes. Thus, Tβ4 is an important MRTF regulator that controls the G-actin-MRTFs interaction. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPβ expression and activation.

    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.

  4. Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPβ expression and activation

    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.

  5. Andrographolide inhibits adipogenesis of 3T3-L1 cells by suppressing C/EBPβ expression and activation

    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.

  6. Model of transcriptional activation by MarA in Escherichia coli.

    Wall, Michael E; Markowitz, David A; Rosner, Judah L; Martin, Robert G

    2009-12-01

    The AraC family transcription factor MarA activates approximately 40 genes (the marA/soxS/rob regulon) of the Escherichia coli chromosome resulting in different levels of resistance to a wide array of antibiotics and to superoxides. Activation of marA/soxS/rob regulon promoters occurs in a well-defined order with respect to the level of MarA; however, the order of activation does not parallel the strength of MarA binding to promoter sequences. To understand this lack of correspondence, we developed a computational model of transcriptional activation in which a transcription factor either increases or decreases RNA polymerase binding, and either accelerates or retards post-binding events associated with transcription initiation. We used the model to analyze data characterizing MarA regulation of promoter activity. The model clearly explains the lack of correspondence between the order of activation and the MarA-DNA affinity and indicates that the order of activation can only be predicted using information about the strength of the full MarA-polymerase-DNA interaction. The analysis further suggests that MarA can activate without increasing polymerase binding and that activation can even involve a decrease in polymerase binding, which is opposite to the textbook model of activation by recruitment. These findings are consistent with published chromatin immunoprecipitation assays of interactions between polymerase and the E. coli chromosome. We find that activation involving decreased polymerase binding yields lower latency in gene regulation and therefore might confer a competitive advantage to cells. Our model yields insights into requirements for predicting the order of activation of a regulon and enables us to suggest that activation might involve a decrease in polymerase binding which we expect to be an important theme of gene regulation in E. coli and beyond.

  7. Model of transcriptional activation by MarA in Escherichia coli.

    Michael E Wall

    2009-12-01

    Full Text Available The AraC family transcription factor MarA activates approximately 40 genes (the marA/soxS/rob regulon of the Escherichia coli chromosome resulting in different levels of resistance to a wide array of antibiotics and to superoxides. Activation of marA/soxS/rob regulon promoters occurs in a well-defined order with respect to the level of MarA; however, the order of activation does not parallel the strength of MarA binding to promoter sequences. To understand this lack of correspondence, we developed a computational model of transcriptional activation in which a transcription factor either increases or decreases RNA polymerase binding, and either accelerates or retards post-binding events associated with transcription initiation. We used the model to analyze data characterizing MarA regulation of promoter activity. The model clearly explains the lack of correspondence between the order of activation and the MarA-DNA affinity and indicates that the order of activation can only be predicted using information about the strength of the full MarA-polymerase-DNA interaction. The analysis further suggests that MarA can activate without increasing polymerase binding and that activation can even involve a decrease in polymerase binding, which is opposite to the textbook model of activation by recruitment. These findings are consistent with published chromatin immunoprecipitation assays of interactions between polymerase and the E. coli chromosome. We find that activation involving decreased polymerase binding yields lower latency in gene regulation and therefore might confer a competitive advantage to cells. Our model yields insights into requirements for predicting the order of activation of a regulon and enables us to suggest that activation might involve a decrease in polymerase binding which we expect to be an important theme of gene regulation in E. coli and beyond.

  8. PEA3activates CXCL12transcription in MCF-7breast cancer cells%PEA3 activates CXCL12 transcription in MCF-7 breast cancer cells

    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.

  9. The cellular transcription factor CREB corresponds to activating transcription factor 47 (ATF-47) and forms complexes with a group of polypeptides related to ATF-43.

    Hurst, H C; Masson, N; Jones, N C; Lee, K A

    1990-01-01

    Promoter elements containing the sequence motif CGTCA are important for a variety of inducible responses at the transcriptional level. Multiple cellular factors specifically bind to these elements and are encoded by a multigene family. Among these factors, polypeptides termed activating transcription factor 43 (ATF-43) and ATF-47 have been purified from HeLa cells and a factor referred to as cyclic AMP response element-binding protein (CREB) has been isolated from PC12 cells and rat brain. We...

  10. Dynamic Effects of Topoisomerase I Inhibition on R-Loops and Short Transcripts at Active Promoters.

    Jessica Marinello

    Full Text Available Topoisomerase I-DNA-cleavage complexes (Top1cc stabilized by camptothecin (CPT have specific effects at transcriptional levels. We recently reported that Top1cc increase antisense transcript (aRNAs levels at divergent CpG-island promoters and, transiently, DNA/RNA hybrids (R-loop in nuclear and mitochondrial genomes of colon cancer HCT116 cells. However, the relationship between R-loops and aRNAs was not established. Here, we show that aRNAs can form R-loops in N-TERA-2 cells under physiological conditions, and that promoter-associated R-loops are somewhat increased and extended in length immediately upon cell exposure to CPT. In contrast, persistent Top1ccs reduce the majority of R-loops suggesting that CPT-accumulated aRNAs are not commonly involved in R-loops. The enhancement of aRNAs by Top1ccs is present both in human colon cancer HCT116 cells and WI38 fibroblasts suggesting a common response of cancer and normal cells. Although Top1ccs lead to DSB and DDR kinases activation, we do not detect a dependence of aRNA accumulation on ATM or DNA-PK activation. However, we showed that the cell response to persistent Top1ccs can involve an impairment of aRNA turnover rather than a higher synthesis rate. Finally, a genome-wide analysis shows that persistent Top1ccs also determine an accumulation of sense transcripts at 5'-end gene regions suggesting an increased occurrence of truncated transcripts. Taken together, the results indicate that Top1 may regulate transcription initiation by modulating RNA polymerase-generated negative supercoils, which can in turn favor R-loop formation at promoters, and that transcript accumulation at TSS is a response to persistent transcriptional stress by Top1 poisoning.

  11. MiT/TFE transcription factors are activated during mitophagy downstream of Parkin and Atg5.

    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.

  12. Persistent suppression of subthalamic beta-band activity during rhythmic finger tapping in Parkinson's disease.

    Joundi, Raed A; Brittain, John-Stuart; Green, Alex L; Aziz, Tipu Z; Brown, Peter; Jenkinson, Ned

    2013-03-01

    The function of synchronous oscillatory activity at beta band (15-30Hz) frequencies within the basal ganglia is unclear. Here we sought support for the hypothesis that beta activity has a global function within the basal ganglia and is not directly involved in the coding of specific biomechanical parameters of movement. We recorded local field potential activity from the subthalamic nuclei of 11 patients with Parkinson's disease during a synchronized tapping task at three different externally cued rates. Beta activity was suppressed during tapping, reaching a minimum that differed little across the different tapping rates despite an increase in velocity of finger movements. Thus beta power suppression was independent of specific motor parameters. Moreover, although beta oscillations remained suppressed during all tapping rates, periods of resynchronization between taps were markedly attenuated during high rate tapping. As such, a beta rebound above baseline between taps at the lower rates was absent at the high rate. Our results demonstrate that beta desynchronization in the region of the subthalamic nucleus is independent of motor parameters and that the beta resynchronization is differentially modulated by rate of finger tapping, These findings implicate consistent beta suppression in the facilitation of continuous movement sequences. Copyright © 2012 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  13. Zinc coordination is required for and regulates transcription activation by Epstein-Barr nuclear antigen 1.

    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.

  14. The B-subdomain of the Xenopus laevis XFIN KRAB-AB domain is responsible for its weaker transcriptional repressor activity compared to human ZNF10/Kox1.

    Born, Nadine; Thiesen, Hans-Jürgen; Lorenz, Peter

    2014-01-01

    The Krüppel-associated box (KRAB) domain interacts with the nuclear hub protein TRIM28 to initiate or mediate chromatin-dependent processes like transcriptional repression, imprinting or suppression of endogenous retroviruses. The prototype KRAB domain initially identified in ZNF10/KOX1 encompasses two subdomains A and B that are found in hundreds of zinc finger transcription factors studied in human and murine genomes. Here we demonstrate for the first time transcriptional repressor activity of an amphibian KRAB domain. After sequence correction, the updated KRAB-AB domain of zinc finger protein XFIN from the frog Xenopus laevis was found to confer transcriptional repression in reporter assays in Xenopus laevis A6 kidney cells as well as in human HeLa, but not in the minnow Pimephales promelas fish cell line EPC. Binding of the XFIN KRAB-AB domain to human TRIM28 was demonstrated in a classical co-immunoprecipitation approach and visualized in a single-cell compartmentalization assay. XFIN-AB displayed reduced potency in repression as well as lower strength of interaction with TRIM28 compared to ZNF10 KRAB-AB. KRAB-B subdomain swapping between the two KRAB domains indicated that it was mainly the KRAB-B subdomain of XFIN that was responsible for its lower capacity in repression and binding to human TRIM28. In EPC fish cells, ZNF10 and XFIN KRAB repressor activity could be partially restored to low levels by adding exogenous human TRIM28. In contrast to XFIN, we did not find any transcriptional repression activity for the KRAB-like domain of human PRDM9 in HeLa cells. PRDM9 is thought to harbor an evolutionary older domain related to KRAB whose homologs even occur in invertebrates. Our results support the notion that functional bona fide KRAB domains which confer transcriptional repression and interact with TRIM28 most likely co-evolved together with TRIM28 at the beginning of tetrapode evolution.

  15. Distinct structural features of TFAM drive mitochondrial DNA packaging versus transcriptional activation.

    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.

  16. Nerve growth factor enhances the CRE-dependent transcriptional activity activated by nobiletin in PC12 cells.

    Takito, Jiro; Kimura, Junko; Kajima, Koji; Uozumi, Nobuyuki; Watanabe, Makoto; Yokosuka, Akihito; Mimaki, Yoshihiro; Nakamura, Masanori; Ohizumi, Yasushi

    2016-07-01

    Prevention and treatment of Alzheimer disease are urgent problems for elderly people in developed countries. We previously reported that nobiletin, a poly-methoxylated flavone from the citrus peel, improved the symptoms in various types of animal models of memory loss and activated the cAMP responsive element (CRE)-dependent transcription in PC12 cells. Nobiletin activated the cAMP/PKA/MEK/Erk/MAPK signaling pathway without using the TrkA signaling activated by nerve growth factor (NGF). Here, we examined the effect of combination of nobiletin and NGF on the CRE-dependent transcription in PC12 cells. Although NGF alone had little effect on the CRE-dependent transcription, NGF markedly enhanced the CRE-dependent transcription induced by nobiletin. The NGF-induced enhancement was neutralized by a TrkA antagonist, K252a. This effect of NGF was effective on the early signaling event elicited by nobiletin. These results suggested that there was crosstalk between NGF and nobiletin signaling in activating the CRE-dependent transcription in PC12 cells.

  17. Curcumin suppresses the production of interleukin-6 in Prevotella intermedia lipopolysaccharide-activated RAW 264.7 cells

    2011-01-01

    Purpose Curcumin is known to exert numerous biological effects including anti-inflammatory activity. In this study, we investigated the effects of curcumin on the production of interleukin-6 (IL-6) by murine macrophage-like RAW 264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a major cause of inflammatory periodontal disease, and sought to determine the underlying mechanisms of action. Methods LPS was prepared from lyophilized P. intermedia ATCC 25611 cells by the standard hot phenol-water method. Culture supernatants were collected and assayed for IL-6. We used real-time polymerase chain reaction to detect IL-6 mRNA expression. IκB-α degradation, nuclear translocation of NF-κB subunits, and STAT1 phosphorylation were characterized via immunoblotting. DNA-binding of NF-κB was also analyzed. Results Curcumin strongly suppressed the production of IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW 264.7 cells. Curcumin did not inhibit the degradation of IκB-α induced by P. intermedia LPS. Curcumin blocked NF-κB signaling through the inhibition of nuclear translocation of NF-κB p50 subunit. Curcumin also attenuated DNA binding activity of p50 and p65 subunits and suppressed STAT1 phosphorylation. Conclusions Although further study is required to explore the detailed mechanism of action, curcumin may contribute to blockade of the host-destructive processes mediated by IL-6 and appears to have potential therapeutic values in the treatment of inflammatory periodontal disease. PMID:21811692

  18. Antisense Suppression of 2-Cysteine Peroxiredoxin in Arabidopsis Specifically Enhances the Activities and Expression of Enzymes Associated with Ascorbate Metabolism But Not Glutathione Metabolism1

    Baier, Margarete; Noctor, Graham; Foyer, Christine H.; Dietz, Karl-Josef

    2000-01-01

    The aim of this study was to characterize the effect of decreased 2-cysteine peroxiredoxin (2-CP) on the leaf anti-oxidative system in Arabidopsis. At three stages of leaf development, two lines of transgenic Arabidopsis mutants with decreased contents of chloroplast 2-CP were compared with wild type and a control line transformed with an empty vector. Glutathione contents and redox state were similar in all plants, and no changes in transcript levels for enzymes involved in glutathione metabolism were observed. Transcript levels for chloroplastic glutathione peroxidase were much lower than those for 2-CP, and both cytosolic and chloroplastic glutathione peroxidase were not increased in the mutants. In contrast, the foliar ascorbate pool was more oxidized in the mutants, although the difference decreased with plant age. The activities of thylakoid and stromal ascorbate peroxidase and particularly monodehydroascorbate reductase were increased as were transcripts for these enzymes. No change in dehydroascorbate reductase activity was observed, and effects on transcript abundance for glutathione reductase, catalase, and superoxide dismutase were slight or absent. The results demonstrate that 2-CP forms an integral part of the anti-oxidant network of chloroplasts and is functionally interconnected with other defense systems. Suppression of 2-CP leads to increased expression of other anti-oxidative genes possibly mediated by increased oxidation state of the leaf ascorbate pool. PMID:11027730

  19. HMBA Enhances Prostratin-Induced Activation of Latent HIV-1 via Suppressing the Expression of Negative Feedback Regulator A20/TNFAIP3 in NF-κB Signaling

    Duchu Chen

    2016-01-01

    Full Text Available In the past decade, much emphasis has been put on the transcriptional activation of HIV-1, which is proposed as a promised strategy for eradicating latent HIV-1 provirus. Two drugs, prostratin and hexamethylene bisacetamide (HMBA, have shown potent effects as inducers for releasing HIV-1 latency when used alone or in combination, although their cellular target(s are currently not well understood, especially under drug combination. Here, we have shown that HMBA and prostratin synergistically release HIV-1 latency via different mechanisms. While prostratin strongly stimulates HMBA-induced HIV-1 transcription via improved P-TEFb activation, HMBA is capable of boosting NF-κB-dependent transcription initiation by suppressing prostratin-induced expression of the deubiquitinase A20, a negative feedback regulator in the NF-κB signaling pathway. In addition, HMBA was able to increase prostratin-induced phosphorylation and degradation of NF-κB inhibitor IκBα, thereby enhancing and prolonging prostratin-induced nuclear translocation of NF-κB, a prerequisite for stimulation of transcription initiation. Thus, by blocking the negative feedback circuit, HMBA functions as a signaling enhancer of the NF-κB signaling pathway.

  20. Stat1-Vitamin D Receptor Interactions Antagonize 1,25-Dihydroxyvitamin D Transcriptional Activity and Enhance Stat1-Mediated Transcription

    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

  1. Aqueous fraction from Cuscuta japonica seed suppresses melanin synthesis through inhibition of the p38 mitogen-activated protein kinase signaling pathway in B16F10 cells.

    Jang, Ji Yeon; Kim, Ha Neui; Kim, Yu Ri; Choi, Yung Hyun; Kim, Byung Woo; Shin, Hwa Kyoung; Choi, Byung Tae

    2012-05-07

    Semen cuscutae has been used traditionally to treat pimples and alleviate freckles and melasma in Korea. The present study aimed to investigate the inhibitory effect of Cuscuta japonica Choisy seeds on alpha-melanocyte-stimulating hormone (α-MSH)-induced melanogenesis. The aqueous fraction from Semen cuscutae (AFSC) was used to determine anti-melanogenic effects by examination of cellular melanin contents, tyrosinase activity assay, cAMP assay and Western blot analysis for melanin synthesis-related signaling proteins in B16F10 mouse melanoma cells. AFSC markedly inhibited α-MSH-induced melanin synthesis and tyrosinase activity, and also decreased α-MSH-induced expression of microphthalmia-associated transcription factor (MITF) and tyrosinase-related proteins (TRPs). Moreover, AFSC significantly decreased the level of phosphorylated p38 mitogen-activated protein kinase (MAPK) signaling through the down-regulation of α-MSH-induced cAMP. Furthermore, we confirmed that the specific inhibitor of p38 MAPK (SB203580)-mediated suppressed melanin synthesis and tyrosinase activity was further attenuated by AFSC. AFSC also further decreased SB203580-mediated suppression of MITF and TRP expression. These results indicate that AFSC inhibits p38 MAPK phosphorylation with suppressed cAMP levels and subsequently down-regulate MITF and TRP expression, which results in a marked reduction of melanin synthesis and tyrosinase activity in α-MSH-stimulated B16F10 cells. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Versatility of cooperative transcriptional activation: a thermodynamical modeling analysis for greater-than-additive and less-than-additive effects.

    Till D Frank

    Full Text Available We derive a statistical model of transcriptional activation using equilibrium thermodynamics of chemical reactions. We examine to what extent this statistical model predicts synergy effects of cooperative activation of gene expression. We determine parameter domains in which greater-than-additive and less-than-additive effects are predicted for cooperative regulation by two activators. We show that the statistical approach can be used to identify different causes of synergistic greater-than-additive effects: nonlinearities of the thermostatistical transcriptional machinery and three-body interactions between RNA polymerase and two activators. In particular, our model-based analysis suggests that at low transcription factor concentrations cooperative activation cannot yield synergistic greater-than-additive effects, i.e., DNA transcription can only exhibit less-than-additive effects. Accordingly, transcriptional activity turns from synergistic greater-than-additive responses at relatively high transcription factor concentrations into less-than-additive responses at relatively low concentrations. In addition, two types of re-entrant phenomena are predicted. First, our analysis predicts that under particular circumstances transcriptional activity will feature a sequence of less-than-additive, greater-than-additive, and eventually less-than-additive effects when for fixed activator concentrations the regulatory impact of activators on the binding of RNA polymerase to the promoter increases from weak, to moderate, to strong. Second, for appropriate promoter conditions when activator concentrations are increased then the aforementioned re-entrant sequence of less-than-additive, greater-than-additive, and less-than-additive effects is predicted as well. Finally, our model-based analysis suggests that even for weak activators that individually induce only negligible increases in promoter activity, promoter activity can exhibit greater

  3. Fe65 does not stabilize AICD during activation of transcription in a luciferase assay

    Huysseune, Sandra; Kienlen-Campard, Pascal; Octave, Jean-Noel

    2007-01-01

    The APP intracellular domain (AICD) could be involved in signaling via interaction with the adaptor protein Fe65, and with the histone acetyl transferase Tip60. However, the real function of AICD and Fe65 in regulation of transcription remains controversial. In this study, the human APPGal4 fusion protein was expressed in CHO cells and the transcriptional activity of AICDGal4 was measured in a luciferase-based reporter assay. AICDGal4 was stabilized by expression of Fe65 and levels of AICDGal4 controlled luciferase activity. On the contrary, when human APP was expressed in CHO cells, coexpression of Fe65 increased luciferase activity without affecting the amount of AICD fragment. AICD produced from APP was protected from degradation by orthophenanthroline, but not by lactacystine, indicating that AICD is not a substrate of the chymotryptic activity of the proteasome. It is concluded that Fe65 can control luciferase activity without stabilizing the labile AICD fragment

  4. Suppression of SOS-inducing activity of chemical mutagens by metabolites from microbial transformation of (-)-isolongifolene.

    Sakata, Kazuki; Oda, Yoshimitsu; Miyazawa, Mitsuo

    2010-02-24

    In this study, biotransformation of (-)-isolongifolene (1) by Glomerella cingulata and suppressive effect on umuC gene expression by chemical mutagens 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) and aflatoxin B(1) (AFB(1)) of the SOS response in Salmonella typhimurium TA1535/pSK1002 were investigated. Initially, 1 was carried out the microbial transformation by G. cingulata. The result found that 1 was converted into (-)-isolongifolen-9-one (2), (-)-(2S)-13-hydroxy-isolongifolen-9-one (3), and (-)-(4R)-4-hydroxy-isolongifolen-9-one (4) by G. cingulata, and their conversion rates were 60, 25, and 15%, respectively. The metabolites suppressed the SOS-inducing activity of furylfuramid and AFB(1) in the umu test. Comound 2 showed gene expression by chemical mutagens furylfuramide and AFB(1) was suppressed 54 and 50% at <0.5 mM, respectively. Compound 2 is the most effective compound in this experiment.

  5. Comparison of analysis and flight test data for a drone aircraft with active flutter suppression

    Newsom, J. R.; Pototzky, A. S.

    1981-01-01

    A drone aircraft equipped with an active flutter suppression system is considered with emphasis on the comparison of modal dampings and frequencies as a function of Mach number. Results are presented for both symmetric and antisymmetric motion with flutter suppression off. Only symmetric results are given for flutter suppression on. Frequency response functions of the vehicle are presented from both flight test data and analysis. The analysis correlation is improved by using an empirical aerodynamic correction factor which is proportional to the ratio of experimental to analytical steady-state lift curve slope. The mathematical models are included and existing analytical techniques are described as well as an alternative analytical technique for obtaining closed-loop results.

  6. Malondialdehyde inhibits an AMPK-mediated nuclear translocation and repression activity of ALDH2 in transcription

    Choi, Ji-Woong; Kim, Jae-Hwan; Cho, Sung-Chun; Ha, Moon-Kyung; Song, Kye-Yong; Youn, Hong-Duk; Park, Sang Chul

    2011-01-01

    Research highlights: → ALDH2 is an MDA-modified protein in old rat kidney tissues. → AMPK associates with ALDH2 and triggers the nuclear localization of ALDH2. → ALDH2 serves as a general transcriptional repressor by associating with HDACs. → MDA inhibits the AMPK-mediated translocation of ALDH2 and its repression activity. -- Abstract: Aging process results from deleterious damages by reactive oxygen species, in particular, various metabolic aldehydes. Aldehyde dehydrogenase 2 (ALDH2) is one of metabolic enzymes detoxifying various aldehydes under oxidative conditions. AMP-activated protein kinase (AMPK) plays a key role in controlling metabolic process. However, little was known about the relationship of ALDH2 with AMPK under oxidative conditions. Here, we, by using MDA-specific monoclonal antibody, screened the tissues of young and old rats for MDA-modified proteins and identified an ALDH2 as a prominent MDA-modified protein band in the old rat kidney tissue. ALDH2 associates with AMPK and is phosphorylated by AMPK. In addition, AICAR, an activator of AMP-activated protein kinase, induces the nuclear translocation of ALDH2. ALDH2 in nucleus is involved in general transcription repression by association with histone deacetylases. Furthermore, MDA modification inhibited the translocation of ALDH2 and the association with AMPK, and ultimately led to de-repression of transcription in the reporter system analysis. In this study, we have demonstrated that ALDH2 acts as a transcriptional repressor in response to AMPK activation, and MDA modifies ALDH2 and inhibits repressive activity of ALDH2 in general transcription. We thus suggest that increasing amount of MDA during aging process may interrupt the nuclear function of ALDH2, modulated by AMPK.

  7. Malondialdehyde inhibits an AMPK-mediated nuclear translocation and repression activity of ALDH2 in transcription

    Choi, Ji-Woong [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799, (Korea, Republic of); Kim, Jae-Hwan [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Cho, Sung-Chun; Ha, Moon-Kyung [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799, (Korea, Republic of); Song, Kye-Yong [Department of Pathology, Chung-Ang University College of Medicine, Seoul 156-756 (Korea, Republic of); Youn, Hong-Duk, E-mail: hdyoun@snu.ac.kr [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Park, Sang Chul, E-mail: scpark@snu.ac.kr [Department of Biomedical Sciences and Biochemistry and Molecular Biology, Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799 (Korea, Republic of); Aging and Apoptosis Research Center (AARC), Seoul National University College of Medicine, 28 Yongon-dong, Chongro-gu, Seoul 110-799, (Korea, Republic of)

    2011-01-07

    Research highlights: {yields} ALDH2 is an MDA-modified protein in old rat kidney tissues. {yields} AMPK associates with ALDH2 and triggers the nuclear localization of ALDH2. {yields} ALDH2 serves as a general transcriptional repressor by associating with HDACs. {yields} MDA inhibits the AMPK-mediated translocation of ALDH2 and its repression activity. -- Abstract: Aging process results from deleterious damages by reactive oxygen species, in particular, various metabolic aldehydes. Aldehyde dehydrogenase 2 (ALDH2) is one of metabolic enzymes detoxifying various aldehydes under oxidative conditions. AMP-activated protein kinase (AMPK) plays a key role in controlling metabolic process. However, little was known about the relationship of ALDH2 with AMPK under oxidative conditions. Here, we, by using MDA-specific monoclonal antibody, screened the tissues of young and old rats for MDA-modified proteins and identified an ALDH2 as a prominent MDA-modified protein band in the old rat kidney tissue. ALDH2 associates with AMPK and is phosphorylated by AMPK. In addition, AICAR, an activator of AMP-activated protein kinase, induces the nuclear translocation of ALDH2. ALDH2 in nucleus is involved in general transcription repression by association with histone deacetylases. Furthermore, MDA modification inhibited the translocation of ALDH2 and the association with AMPK, and ultimately led to de-repression of transcription in the reporter system analysis. In this study, we have demonstrated that ALDH2 acts as a transcriptional repressor in response to AMPK activation, and MDA modifies ALDH2 and inhibits repressive activity of ALDH2 in general transcription. We thus suggest that increasing amount of MDA during aging process may interrupt the nuclear function of ALDH2, modulated by AMPK.

  8. Targeted deficiency of the transcriptional activator Hnf1alpha alters subnuclear positioning of its genomic targets.

    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.

  9. Cross activity of orthologous WRKY transcription factors in wheat and Arabidopsis

    Poietti, S.; Bertini, L.; Ent, S. van der; Leon Reyes, H.A.; Pieterse, C.M.J.; Tucci, M.; Caporale, C.; Caruso, C.

    2011-01-01

    WRKY proteins are transcription factors involved in many plant processes including plant responses to pathogens. Here, the cross activity of TaWRKY78 from the monocot wheat and AtWRKY20 from the dicot Arabidopsis on the cognate promoters of the orthologous PR4-type genes wPR4e and AtHEL of wheat and

  10. Altered association of transcriptionally active DNA with the nuclear-matrix after heat shock

    Sakkers, RJ; Brunsting, JF; Filon, AR; Kampinga, HH; Konings, AWT; Mullenders, LHF

    Purpose: Exposure of human cells to heat leads to denaturation and aggregation of proteins. Within the nucleus, it has been suggested that protein aggregation is linked to the: selective inhibition by hyperthermia of nucleotide excision repair in transcriptionally active genes. Tn this study it was

  11. Virulent Type A Francisella tularensis actively suppresses cytokine responses in human monocytes

    Devyn D Gilette

    2014-04-01

    Full Text Available Francisella tularensis is a Gram-negative facultative bacterium that can cause the disease tularemia, even upon exposure to low numbers of bacteria. One critical characteristic of Francisella is its ability to dampen or subvert the host immune response. Previous work has shown that monocytes infected with highly virulent F. tularensis subsp. tularensis strain Schu S4 responded with a general pattern of quantitatively reduced pro-inflammatory signaling pathway genes and cytokine production in comparison to those infected with the less virulent related F. novicida. However, it has been unclear whether the virulent Schu S4 was merely evading or actively suppressing monocyte responses. By using mixed infection assays with F. tularensis and F. novicida, we show that F. tularensis actively suppresses monocyte pro-inflammatory responses. Additional experiments show that this suppression occurs in a dose-dependent manner and is dependent upon the viability of F. tularensis. Importantly, F. tularensis was able to suppress pro-inflammatory responses to earlier infections with F. novicida. These results lend support that F. tularensis actively dampens human monocyte responses and this likely contributes to its enhanced pathogenicity.

  12. High resolution analysis of the human transcriptome: detection of extensive alternative splicing independent of transcriptional activity

    Rouet Fabien

    2009-10-01

    transcriptional activity, indicating that the controls for transcript generation and transcription are distinct, and require novel tools in order to detect changes in specific transcript quantity. Our results demonstrate that the SpliceArray™ design will provide researchers with a robust platform to detect and quantify specific changes not only in overall gene expression, but also at the individual transcript level.

  13. Arctigenin promotes degradation of inducible nitric oxide synthase through CHIP-associated proteasome pathway and suppresses its enzyme activity.

    Yao, Xiangyang; Li, Guilan; Lü, Chaotian; Xu, Hui; Yin, Zhimin

    2012-10-01

    Arctigenin, a natural dibenzylbutyrolactone lignan compound, has been reported to possess anti-inflammatory properties. Previous works showed that arctigenin decreased lipopolysaccharide (LPS)-induced iNOS at transcription level. However, whether arctigenin could regulate iNOS at the post-translational level is still unclear. In the present study, we demonstrated that arctigenin promoted the degradation of iNOS which is expressed under LPS stimulation in murine macrophage-like RAW 264.7 cells. Such degradation of iNOS protein is due to CHIP-associated ubiquitination and proteasome-dependency. Furthermore, arctigenin decreased iNOS phosphorylation through inhibiting ERK and Src activation, subsequently suppressed iNOS enzyme activity. In conclusion, our research displays a new finding that arctigenin can promote the ubiqitination and degradation of iNOS after LPS stimulation. iNOS activity regulated by arctigenin is likely to involve a multitude of crosstalking mechanisms. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Suppression of resistive wall instabilities with distributed, independently controlled, active feedback coils

    Cates, C.; Shilov, M.; Mauel, M. E.; Navratil, G. A.; Maurer, D.; Mukherjee, S.; Nadle, D.; Bialek, J.; Boozer, A.

    2000-01-01

    External kink instabilities are suppressed in a tokamak experiment by either (1) energizing a distributed array of independently controlled active feedback coils mounted outside a segmented resistive wall or (2) inserting a second segmented wall having much higher electrical conductivity. When the active feedback coils are off and the highly conducting wall is withdrawn, kink instabilities excited by plasma current gradients grow at a rate comparable to the magnetic diffusion rate of the resistive wall. (c) 2000 American Institute of Physics

  15. Elk3 from hamster-a ternary complex factor with strong transcriptional repressor activity

    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...

  16. Increased accumulation of hypoxia-inducible factor-1α with reduced transcriptional activity mediates the antitumor effect of triptolide

    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

  17. Commensal Streptococcus salivarius Modulates PPARγ Transcriptional Activity in Human Intestinal Epithelial Cells.

    Benoît Couvigny

    Full Text Available The impact of commensal bacteria in eukaryotic transcriptional regulation has increasingly been demonstrated over the last decades. A multitude of studies have shown direct effects of commensal bacteria from local transcriptional activity to systemic impact. The commensal bacterium Streptococcus salivarius is one of the early bacteria colonizing the oral and gut mucosal surfaces. It has been shown to down-regulate nuclear transcription factor (NF-кB in human intestinal cells, a central regulator of the host mucosal immune system response to the microbiota. In order to evaluate its impact on a further important transcription factor shown to link metabolism and inflammation in the intestine, namely PPARγ (peroxisome proliferator-activated receptor, we used human intestinal epithelial cell-lines engineered to monitor PPARγ transcriptional activity in response to a wide range of S. salivarius strains. We demonstrated that different strains from this bacterial group share the property to inhibit PPARγ activation independently of the ligand used. First attempts to identify the nature of the active compounds showed that it is a low-molecular-weight, DNase-, proteases- and heat-resistant metabolite secreted by S. salivarius strains. Among PPARγ-targeted metabolic genes, I-FABP and Angptl4 expression levels were dramatically reduced in intestinal epithelial cells exposed to S. salivarius supernatant. Both gene products modulate lipid accumulation in cells and down-regulating their expression might consequently affect host health. Our study shows that species belonging to the salivarius group of streptococci impact both host inflammatory and metabolic regulation suggesting a possible role in the host homeostasis and health.

  18. A transcription activator-like effector (TALE) induction system mediated by proteolysis.

    Copeland, Matthew F; Politz, Mark C; Johnson, Charles B; Markley, Andrew L; Pfleger, Brian F

    2016-04-01

    Simple and predictable trans-acting regulatory tools are needed in the fields of synthetic biology and metabolic engineering to build complex genetic circuits and optimize the levels of native and heterologous gene products. Transcription activator-like effectors (TALEs) are bacterial virulence factors that have recently gained traction in biotechnology applications owing to their customizable DNA-binding specificity. In this work we expanded the versatility of these transcription factors to create an inducible TALE system by inserting tobacco-etch virus (TEV) protease recognition sites into the TALE backbone. The resulting engineered TALEs maintain transcriptional repression of their target genes in Escherichia coli, but are degraded after induction of the TEV protease, thereby promoting expression of the previously repressed target gene of interest. This TALE-TEV technology enables both repression and induction of plasmid or chromosomal target genes in a manner analogous to traditional repressor proteins but with the added flexibility of being operator-agnostic.

  19. E2F1 transcription is induced by genotoxic stress through ATM/ATR activation.

    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.

  20. Modifiers of notch transcriptional activity identified by genome-wide RNAi

    Firnhaber Christopher B

    2010-10-01

    Full Text Available Abstract Background The Notch signaling pathway regulates a diverse array of developmental processes, and aberrant Notch signaling can lead to diseases, including cancer. To obtain a more comprehensive understanding of the genetic network that integrates into Notch signaling, we performed a genome-wide RNAi screen in Drosophila cell culture to identify genes that modify Notch-dependent transcription. Results Employing complementary data analyses, we found 399 putative modifiers: 189 promoting and 210 antagonizing Notch activated transcription. These modifiers included several known Notch interactors, validating the robustness of the assay. Many novel modifiers were also identified, covering a range of cellular localizations from the extracellular matrix to the nucleus, as well as a large number of proteins with unknown function. Chromatin-modifying proteins represent a major class of genes identified, including histone deacetylase and demethylase complex components and other chromatin modifying, remodeling and replacement factors. A protein-protein interaction map of the Notch-dependent transcription modifiers revealed that a large number of the identified proteins interact physically with these core chromatin components. Conclusions The genome-wide RNAi screen identified many genes that can modulate Notch transcriptional output. A protein interaction map of the identified genes highlighted a network of chromatin-modifying enzymes and remodelers that regulate Notch transcription. Our results open new avenues to explore the mechanisms of Notch signal regulation and the integration of this pathway into diverse cellular processes.

  1. Condensation of chromatin in transcriptional regions of an inactivated plant transgene: evidence for an active role of transcription in gene silencing.

    van Blokland, R; ten Lohuis, M; Meyer, P

    1997-12-01

    The chromatin structures of two epigenetic alleles of a transgene were investigated by measuring the local accessibility of transgene chromatin to endonucleases. The two epialleles represented the active, hypomethylated state of a transgene in line 17-I of Petunia hybrida, and a transcriptionally inactive, hypermethylated derivative of the same transgene in line 17-IV. In nuclear preparations the inactive epiallele was significantly less sensitive to DNasel digestion and nuclease S7 digestion than the transcriptionally active epiallele, whereas no significant differences in accessibility were observed between naked DNA samples of the two epialleles. Our data suggest that a condensed chromatin structure is specifically imposed on transcribed regions of the construct in line 17-IV. In contrast, in both epialleles the plasmid region of the transgene, which is not transcriptionally active in plants, retains the same accessibility to endonucleases as the chromosomal integration site. These data suggest that transcriptional inactivation is linked to the process of transcription, and imply that control of transgene expression via the use of inducible or tissue-specific promoters might prevent transgene silencing and conserve the active state of transgenes during sexual propagation.

  2. Suppression of EMG activity by transcranial magnetic stimulation in human subjects during walking

    Petersen, Nicolas Caesar; Butler, Jane E; Marchand-Pauvert, Veronique

    2001-01-01

    1. The involvement of the motor cortex during human walking was evaluated using transcranial magnetic stimulation (TMS) of the motor cortex at a variety of intensities. Recordings of EMG activity in tibialis anterior (TA) and soleus muscles during walking were rectified and averaged. 2. TMS of low...... intensity (below threshold for a motor-evoked potential, MEP) produced a suppression of ongoing EMG activity during walking. The average latency for this suppression was 40.0 +/- 1.0 ms. At slightly higher intensities of stimulation there was a facilitation of the EMG activity with an average latency of 29.......5 +/- 1.0 ms. As the intensity of the stimulation was increased the facilitation increased in size and eventually a MEP was clear in individual sweeps. 3. In three subjects TMS was replaced by electrical stimulation over the motor cortex. Just below MEP threshold there was a clear facilitation at short...

  3. Expression, processing and transcriptional regulation of granulysin in short-term activated human lymphocytes

    Groscurth Peter

    2007-06-01

    Full Text Available Abstract Background Granulysin, a cytotoxic protein expressed in human natural killer cells and activated T lymphocytes, exhibits cytolytic activity against a variety of intracellular microbes. Expression and transcription have been partially characterised in vitro and four transcripts (NKG5, 519, 520, and 522 were identified. However, only a single protein product of 15 kDa was found, which is subsequently processed to an active 9 kDa protein. Results In this study we investigated generation of granulysin in lymphokine activated killer (LAK cells and antigen (Listeria specific T-cells. Semiquantitative RT-PCR revealed NKG5 to be the most prominent transcript. It was found to be up-regulated in a time-dependent manner in LAK cells and antigen specific T-cells and their subsets. Two isoforms of 519 mRNA were up-regulated under IL-2 and antigen stimulation. Moreover, two novel transcripts, without any known function, comprising solely parts of the 5 prime region of the primary transcript, were detected. A significant increase of granulysin expressing LAK cells as well as antigen specific T-cells was shown by fluorescence microscopy. On the subset level, increase in CD4+ granulysin expressing cells was found only under antigen stimulation. Immunoblotting showed the 15 kDa form of granulysin to be present in the first week of stimulation either with IL-2 or with bacterial antigen. Substantial processing to the 9 kDa form was detected during the first week in LAK cells and in the second week in antigen specific T-cells. Conclusion This first comprehensive study of granulysin gene regulation in primary cultured human lymphocytes shows that the regulation of granulysin synthesis in response to IL-2 or bacterial antigen stimulation occurs at several levels: RNA expression, extensive alternative splicing and posttranslational processing.

  4. Suppressive oligodeoxynucleotides containing TTAGGG motifs inhibit cGAS activation in human monocytes.

    Steinhagen, Folkert; Zillinger, Thomas; Peukert, Konrad; Fox, Mario; Thudium, Marcus; Barchet, Winfried; Putensen, Christian; Klinman, Dennis; Latz, Eicke; Bode, Christian

    2018-04-01

    Type I interferon (IFN) is a critical mediator of autoimmune diseases such as systemic lupus erythematosus (SLE) and Aicardi-Goutières Syndrome (AGS). The recently discovered cyclic-GMP-AMP (cGAMP) synthase (cGAS) induces the production of type I IFN in response to cytosolic DNA and is potentially linked to SLE and AGS. Suppressive oligodeoxynucleotides (ODN) containing repetitive TTAGGG motifs present in mammalian telomeres have proven useful in the treatment of autoimmune diseases including SLE. In this study, we demonstrate that the suppressive ODN A151 effectively inhibits activation of cGAS in response to cytosolic DNA, thereby inhibiting type I IFN production by human monocytes. In addition, A151 abrogated cGAS activation in response to endogenous accumulation of DNA using TREX1-deficient monocytes. We demonstrate that A151 prevents cGAS activation in a manner that is competitive with DNA. This suppressive activity of A151 was dependent on both telomeric sequence and phosphorothioate backbone. To our knowledge this report presents the first cGAS inhibitor capable of blocking self-DNA. Collectively, these findings might lead to the development of new therapeutics against IFN-driven pathologies due to cGAS activation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Locked and proteolysis-based transcription activator-like effector (TALE) regulation.

    Lonzarić, Jan; Lebar, Tina; Majerle, Andreja; Manček-Keber, Mateja; Jerala, Roman

    2016-02-18

    Development of orthogonal, designable and adjustable transcriptional regulators is an important goal of synthetic biology. Their activity has been typically modulated through stimulus-induced oligomerization or interaction between the DNA-binding and activation/repression domain. We exploited a feature of the designable Transcription activator-like effector (TALE) DNA-binding domain that it winds around the DNA which allows to topologically prevent it from binding by intramolecular cyclization. This new approach was investigated through noncovalent ligand-induced cyclization or through a covalent split intein cyclization strategy, where the topological inhibition of DNA binding by cyclization and its restoration by a proteolytic release of the topologic constraint was expected. We show that locked TALEs indeed have diminished DNA binding and regain full transcriptional activity by stimulation with the rapamycin ligand or site-specific proteolysis of the peptide linker, with much higher level of activation than rapamycin-induced heterodimerization. Additionally, we demonstrated reversibility, activation of genomic targets and implemented logic gates based on combinations of protein cyclization, proteolytic cleavage and ligand-induced dimerization, where the strongest fold induction was achieved by the proteolytic cleavage of a repression domain from a linear TALE. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  6. The hepatitis B virus large surface protein (LHBs) is a transcriptional activator.

    Hildt, E; Saher, G; Bruss, V; Hofschneider, P H

    1996-11-01

    It has been shown that a C-terminally truncated form of the middle-sized hepatitis B virus (HBV) surface protein (MHBst) functions as a transcriptional activator. This function is dependent on the cytosolic orientation of the N-terminal PreS2 domain of MHBst, but in the case of wild-type MHBs, the PreS2 domain is contranslationally translocated into the ER lumen. Recent reports demonstrated that the PreS2 domain of the large HBV surface protein (LHBs) initially remains on the cytosolic side of the ER membrane after translation. Therefore, the question arose as to whether the LHBs protein exhibits the same transcriptional activator function as MHBst. We show that LHBs, like MHBst, is indeed able to activate a variety of promoter elements. There is evidence for a PKC-dependent activation of AP-1 and NF-kappa B by LHBs. Downstream of the PKC the functionality of c-Raf-1 kinase is a prerequisite for LHBs-dependent activation of AP-1 and NF-kappa B since inhibition of c-Raf-1 kinase abolishes LHBs-dependent transcriptional activation of AP-1 and NF-kappa B.

  7. Genome-scale transcriptional activation by an engineered CRISPR-Cas9 complex.

    Konermann, Silvana; Brigham, Mark D; Trevino, Alexandro E; Joung, Julia; Abudayyeh, Omar O; Barcena, Clea; Hsu, Patrick D; Habib, Naomi; Gootenberg, Jonathan S; Nishimasu, Hiroshi; Nureki, Osamu; Zhang, Feng

    2015-01-29

    Systematic interrogation of gene function requires the ability to perturb gene expression in a robust and generalizable manner. Here we describe structure-guided engineering of a CRISPR-Cas9 complex to mediate efficient transcriptional activation at endogenous genomic loci. We used these engineered Cas9 activation complexes to investigate single-guide RNA (sgRNA) targeting rules for effective transcriptional activation, to demonstrate multiplexed activation of ten genes simultaneously, and to upregulate long intergenic non-coding RNA (lincRNA) transcripts. We also synthesized a library consisting of 70,290 guides targeting all human RefSeq coding isoforms to screen for genes that, upon activation, confer resistance to a BRAF inhibitor. The top hits included genes previously shown to be able to confer resistance, and novel candidates were validated using individual sgRNA and complementary DNA overexpression. A gene expression signature based on the top screening hits correlated with markers of BRAF inhibitor resistance in cell lines and patient-derived samples. These results collectively demonstrate the potential of Cas9-based activators as a powerful genetic perturbation technology.

  8. Cocoa Procyanidins Suppress Transformation by Inhibiting Mitogen-activated Protein Kinase Kinase*S⃞

    Kang, Nam Joo; Lee, Ki Won; Lee, Dong Eun; Rogozin, Evgeny A.; Bode, Ann M.; Lee, Hyong Joo; Dong, Zigang

    2008-01-01

    Cocoa was shown to inhibit chemically induced carcinogenesis in animals and exert antioxidant activity in humans. However, the molecular mechanisms of the chemopreventive potential of cocoa and its active ingredient(s) remain unknown. Here we report that cocoa procyanidins inhibit neoplastic cell transformation by suppressing the kinase activity of mitogen-activated protein kinase kinase (MEK). A cocoa procyanidin fraction (CPF) and procyanidin B2 at 5 μg/ml and 40 μm, respectively, inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neoplastic transformation of JB6 P+ mouse epidermal (JB6 P+) cells by 47 and 93%, respectively. The TPA-induced promoter activity and expression of cyclooxygenase-2, which is involved in tumor promotion and inflammation, were dose-dependently inhibited by CPF or procyanidin B2. The activation of activator protein-1 and nuclear factor-κB induced by TPA was also attenuated by CPF or procyanidin B2. The TPA-induced phosphorylation of MEK, extracellular signal-regulated kinase, and p90 ribosomal s6 kinase was suppressed by CPF or procyanidin B2. In vitro and ex vivo kinase assay data demonstrated that CPF or procyanidin B2 inhibited the kinase activity of MEK1 and directly bound with MEK1. CPF or procyanidin B2 suppressed JB6 P+ cell transformation induced by epidermal growth factor or H-Ras, both of which are known to be involved in MEK/ERK signal activation. In contrast, theobromine (up to 80 μm) had no effect on TPA-induced transformation, cyclooxygenase-2 expression, the transactivation of activator protein-1 or nuclear factor-κB, or MEK. Notably, procyanidin B2 exerted stronger inhibitory effects compared with PD098059 (a well known pharmacological inhibitor of MEK) on MEK1 activity and neoplastic cell transformation. PMID:18519570

  9. The Ebola Virus Nucleoprotein Recruits the Host PP2A-B56 Phosphatase to Activate Transcriptional Support Activity of VP30

    Kruse, Thomas; Biedenkopf, Nadine; Hertz, Emil Peter Thrane

    2018-01-01

    Transcription of the Ebola virus genome depends on the viral transcription factor VP30 in its unphosphorylated form, but the underlying molecular mechanism of VP30 dephosphorylation is unknown. Here we show that the Ebola virus nucleoprotein (NP) recruits the host PP2A-B56 protein phosphatase......A-B56 and show that it suppresses Ebola virus transcription and infection. This work dissects the molecular mechanism of VP30 dephosphorylation by PP2A-B56, and it pinpoints this phosphatase as a potential target for therapeutic intervention....

  10. Transcriptional activation of peroxisome proliferator-activated receptor-γ requires activation of both protein kinase A and Akt during adipocyte differentiation

    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.

  11. Resveratrol induces growth arrest and apoptosis through activation of FOXO transcription factors in prostate cancer cells.

    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

  12. Therapeutic doses of irradiation activate viral transcription and induce apoptosis in HIV-1 infected cells

    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

  13. Therapeutic doses of irradiation activate viral transcription and induce apoptosis in HIV-1 infected cells

    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

  14. n-Butyrate inhibits Jun NH(2)-terminal kinase activation and cytokine transcription in mast cells

    Diakos, Christos; Prieschl, Eva E.; Saeemann, Marcus D.; Boehmig, Georg A.; Csonga, Robert; Sobanov, Yury; Baumruker, Thomas; Zlabinger, Gerhard J.

    2006-01-01

    Mast cells are well known to contribute to type I allergic conditions but only recently have been brought in association with chronic relapsing/remitting autoimmune diseases such as celiac disease and ulcerative colitis. Since the bacterial metabolite n-butyrate is considered to counteract intestinal inflammation we investigated the effects of this short chain fatty acid on mast cell activation. Using RNAse protection assays and reporter gene technology we show that n-butyrate downregulates TNF-α transcription. This correlates with an impaired activation of the Jun NH(2)-terminal kinase (JNK) but not other MAP kinases such as ERK and p38 that are largely unaffected by n-butyrate. As a consequence, we observed a decreased nuclear activity of AP-1 and NF-AT transcription factors. These results indicate that n-butyrate inhibits critical inflammatory mediators in mast cells by relatively selectively targeting the JNK signalling

  15. The metazoan Mediator co-activator complex as an integrative hub for transcriptional regulation.

    Malik, Sohail; Roeder, Robert G

    2010-11-01

    The Mediator is an evolutionarily conserved, multiprotein complex that is a key regulator of protein-coding genes. In metazoan cells, multiple pathways that are responsible for homeostasis, cell growth and differentiation converge on the Mediator through transcriptional activators and repressors that target one or more of the almost 30 subunits of this complex. Besides interacting directly with RNA polymerase II, Mediator has multiple functions and can interact with and coordinate the action of numerous other co-activators and co-repressors, including those acting at the level of chromatin. These interactions ultimately allow the Mediator to deliver outputs that range from maximal activation of genes to modulation of basal transcription to long-term epigenetic silencing.

  16. The Calmodulin-Binding Transcription Activator CAMTA1 Is Required for Long-Term Memory Formation in Mice

    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…

  17. Dimer formation and transcription activation in the sporulation response regulator Spo0A.

    Lewis, Richard J; Scott, David J; Brannigan, James A; Ladds, Joanne C; Cervin, Marguerite A; Spiegelman, George B; Hoggett, James G; Barák, Imrich; Wilkinson, Anthony J

    2002-02-15

    The response regulator Spo0A is the master control element in the initiation of sporulation in Bacillus subtilis. Like many other multi-domain response regulators, the latent activity of the effector, C-terminal domain is stimulated by phosphorylation on a conserved aspartic acid residue in the regulatory, N-terminal domain. If a threshold concentration of phosphorylated Spo0A is achieved, the transcription of genes required for sporulation is activated, whereas the genes encoding stationary phase sentinels are repressed, and sporulation proceeds. Despite detailed genetic, biochemical and structural characterisation, it is not understood how the phosphorylation signal in the receiver domain is transduced into DNA binding and transcription activation in the distal effector domain. An obstacle to our understanding of Spo0A function is the uncertainty concerning changes in quaternary structure that accompany phosphorylation. Here we have revisited this question and shown unequivocally that Spo0A forms dimers upon phosphorylation and that the subunit interactions in the dimer are mediated principally by the receiver domain. Purified dimers of two mutants of Spo0A, in which the phosphorylatable aspartic acid residue has been substituted, activate transcription from the spoIIG promoter in vitro, whereas monomers do not. This suggests that dimers represent the activated form of Spo0A. Copyright 2002 Elsevier Science Ltd.

  18. Signal transducer and activator of transcription 5 activation is sufficient to drive transcriptional induction of cyclin D2 gene and proliferation of rat pancreatic beta-cells

    Friedrichsen, Birgitte N; Richter, Henrijette E; Hansen, Johnny A

    2003-01-01

    in a time-dependent manner by hGH in INS-1 cells. Inhibition of protein synthesis by coincubation with cycloheximide did not affect the hGH-induced increase of cyclin D2 mRNA levels at 4 h. Expression of a dominant negative STAT5 mutant, STAT5aDelta749, partially inhibited cyclin D2 protein levels. INS-1...... cells transiently transfected with a cyclin D2 promoter-reporter construct revealed a 3- to 5-fold increase of transcriptional activity in response to hGH stimulation. Furthermore, coexpression of a constitutive active STAT5 mutant (either CA-STAT5a or CA-STAT5b) was sufficient to drive transactivation...

  19. RNA-guided transcriptional activation via CRISPR/dCas9 mimics overexpression phenotypes in Arabidopsis.

    Jong-Jin Park

    Full Text Available Clustered regularly interspaced short palindromic repeats (CRISPR and the CRISPR associated protein 9 (Cas9 system allows effective gene modification through RNA-guided DNA targeting. The Cas9 has undergone a series of functional alterations from the original active endonuclease to partially or completely deactivated Cas9. The catalytically deactivated Cas9 (dCas9 offers a platform to regulate transcriptional expression with the addition of activator or repressor domains. We redesigned a CRISPR/Cas9 activation system by adding the p65 transactivating subunit of NF-kappa B and a heat-shock factor 1 (HSF activation domain to dCas9 bound with the VP64 (tetramer of VP16 activation domain for application in plants. The redesigned CRISPR/Cas9 activation system was tested in Arabidopsis to increase endogenous transcriptional levels of production of anthocyanin pigment 1 (PAP1 and Arabidopsis thaliana vacuolar H+-pyrophosphatase (AVP1. The expression of PAP1 was increased two- to three-fold and the activated plants exhibited purple leaves similar to that of PAP1 overexpressors. The AVP1 gene expression was increased two- to five-fold in transgenic plants. In comparison to the wild type, AVP1 activated plants had increased leaf numbers, larger single-leaf areas and improved tolerance to drought stress. The AVP1 activated plants showed similar phenotypes to AVP1 overexpressors. Therefore, the redesigned CRISPR/Cas9 activation system containing modified p65-HSF provides a simple approach for producing activated plants by upregulating endogenous transcriptional levels.

  20. Omega-3 free fatty acids suppress macrophage inflammasome activation by inhibiting NF-κB activation and enhancing autophagy.

    Yolanda Williams-Bey

    Full Text Available The omega-3 (ω3 fatty acid docosahexaenoic acid (DHA can suppress inflammation, specifically IL-1β production through poorly understood molecular mechanisms. Here, we show that DHA reduces macrophage IL-1β production by limiting inflammasome activation. Exposure to DHA reduced IL-1β production by ligands that stimulate the NLRP3, AIM2, and NAIP5/NLRC4 inflammasomes. The inhibition required Free Fatty Acid Receptor (FFAR 4 (also known as GPR120, a G-protein coupled receptor (GPR known to bind DHA. The exposure of cells to DHA recruited the adapter protein β-arrestin1/2 to FFAR4, but not to a related lipid receptor. DHA treatment reduced the initial inflammasome priming step by suppressing the nuclear translocation of NF-κB. DHA also reduced IL-1β levels by enhancing autophagy in the cells. As a consequence macrophages derived from mice lacking the essential autophagy protein ATG7 were partially resistant to suppressive effects of DHA. Thus, DHA suppresses inflammasome activation by two distinct mechanisms, inhibiting the initial priming step and by augmenting autophagy, which limits inflammasome activity.

  1. Multirate flutter suppression system design for the Benchmark Active Controls Technology Wing

    Berg, Martin C.; Mason, Gregory S.

    1994-01-01

    To study the effectiveness of various control system design methodologies, the NASA Langley Research Center initiated the Benchmark Active Controls Project. In this project, the various methodologies will be applied to design a flutter suppression system for the Benchmark Active Controls Technology (BACT) Wing (also called the PAPA wing). Eventually, the designs will be implemented in hardware and tested on the BACT wing in a wind tunnel. This report describes a project at the University of Washington to design a multirate flutter suppression system for the BACT wing. The objective of the project was two fold. First, to develop a methodology for designing robust multirate compensators, and second, to demonstrate the methodology by applying it to the design of a multirate flutter suppression system for the BACT wing. The contributions of this project are (1) development of an algorithm for synthesizing robust low order multirate control laws (the algorithm is capable of synthesizing a single compensator which stabilizes both the nominal plant and multiple plant perturbations; (2) development of a multirate design methodology, and supporting software, for modeling, analyzing and synthesizing multirate compensators; and (3) design of a multirate flutter suppression system for NASA's BACT wing which satisfies the specified design criteria. This report describes each of these contributions in detail. Section 2.0 discusses our design methodology. Section 3.0 details the results of our multirate flutter suppression system design for the BACT wing. Finally, Section 4.0 presents our conclusions and suggestions for future research. The body of the report focuses primarily on the results. The associated theoretical background appears in the three technical papers that are included as Attachments 1-3. Attachment 4 is a user's manual for the software that is key to our design methodology.

  2. Relative left frontal activity in reappraisal and suppression of negative emotion: Evidence from frontal alpha asymmetry (FAA).

    Choi, Damee; Sekiya, Takahiro; Minote, Natsumi; Watanuki, Shigeki

    2016-11-01

    Previous studies have shown that reappraisal (changing the way that one thinks about emotional events) is an effective strategy for regulating emotion, compared with suppression (reducing emotion-expressive behavior). In the present study, we investigated relative left frontal activity when participants were instructed to use reappraisal and suppression of negative emotion, by measuring frontal alpha asymmetry (FAA). Two electroencephalography (EEG) experiments were conducted; FAA was analyzed while 102 healthy participants (59 men, 43 women) watched negative images after being instructed to perform reappraisal (Experiment 1) and suppression (Experiment 2). Habitual use of reappraisal and suppression was also assessed using the emotion regulation questionnaire (ERQ). The results of Experiment 1 showed that relative left frontal activity was greater when instructed to use reappraisal of negative images than when normally viewing negative images. In contrast, we observed no difference between conditions of instructed suppression and normal viewing in Experiment 2. In addition, in male participants, habitual use of reappraisal was positively correlated with increased relative left frontal activity for instructed reappraisal, while habitual use of suppression did not show a significant correlation with changes in relative left frontal activity for instructed suppression. These results suggest that emotional responses to negative images might be decreased for instructed reappraisal, but not suppression. These findings support previous reports that reappraisal is an effective emotion regulation strategy, compared with suppression. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Differential regulation of the transcriptional activity of the glucocorticoid receptor through site-specific phosphorylation

    Raj Kumar

    2008-08-01

    Full Text Available Raj Kumar1, William J Calhoun21Division of Gastroenterology; 2Division of Allergy, Pulmonary, Immunology, Critical Care, and Sleep (APICS, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USAAbstract: Post-translational modifications such as phosphorylation are known to play an important role in the gene regulation by the transcription factors including the nuclear hormone receptor superfamily of which the glucocorticoid receptor (GR is a member. Protein phosphorylation often switches cellular activity from one state to another. Like many other transcription factors, the GR is a phosphoprotein, and phosphorylation plays an important role in the regulation of GR activity. Cell signaling pathways that regulate phosphorylation of the GR and its associated proteins are important determinants of GR function under various physiological conditions. While the role of many phosphorylation sites in the GR is still not fully understood, the role of others is clearer. Several aspects of transcription factor function, including DNA binding affinity, interaction of transactivation domains with the transcription initiation complex, and shuttling between the cytoplasmic compartments, have all been linked to site-specific phosphorylation. All major phosphorylation sites in the human GR are located in the N-terminal domain including the major transactivation domain, AF1. Available literature clearly indicates that many of these potential phosphorylation sites are substrates for multiple kinases, suggesting the potential for a very complex regulatory network. Phosphorylated GR interacts favorably with critical coregulatory proteins and subsequently enhances transcriptional activity. In addition, the activities and specificities of coregulators may be subject to similar regulation by phosphorylation. Regulation of the GR activity due to phosphorylation appears to be site-specific and dependent upon specific cell signaling cascade

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

    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.

  5. Resolving Early Signaling Events in T-Cell Activation Leading to IL-2 and FOXP3 Transcription

    Jeffrey P. Perley

    2014-11-01

    Full Text Available Signal intensity and feedback regulation are known to be major factors in the signaling events stemming from the T-cell receptor (TCR and its various coreceptors, but the exact nature of these relationships remains in question. We present a mathematical model of the complex signaling network involved in T-cell activation with cross-talk between the Erk, calcium, PKC and mTOR signaling pathways. The model parameters are adjusted to fit new and published data on TCR trafficking, Zap70, calcium, Erk and Isignaling. The regulation of the early signaling events by phosphatases, CD45 and SHP1, and the TCR dynamics are critical to determining the behavior of the model. Additional model corroboration is provided through quantitative and qualitative agreement with experimental data collected under different stimulating and knockout conditions. The resulting model is analyzed to investigate how signal intensity and feedback regulation affect TCR- and coreceptor-mediated signal transduction and their downstream transcriptional profiles to predict the outcome for a variety of stimulatory and knockdown experiments. Analysis of the model shows that: (1 SHP1 negative feedback is necessary for preventing hyperactivity in TCR signaling; (2 CD45 is required for TCR signaling, but also partially suppresses it at high expression levels; and (3 elevated FOXP3 and reduced IL-2 signaling, an expression profile often associated with T regulatory cells (Tregs, is observed when the system is subjected to weak TCR and CD28 costimulation or a severe reduction in CD45 activity.

  6. Relationship between soil cellulolytic activity and suppression of seedling blight of barley in arable soils

    Rasmussen, Peter Have; Knudsen, I.; Elmholt, S.

    2002-01-01

    the Hanes-Wolf transformation of the Michaelis-Menten equation. Soil samples from 6 to 13 cm depth were collected in the early spring as undisturbed blocks from 10 arable soils with different physico-chemical properties and cultivation history. Significant correlations were found between soil suppresiveness......The objective was to investigate the relationship between soil suppression of seedling blight of barley caused by Fusarium culmorum (W.G. Smith) Sacc. and the soil cellulolytic activity of beta-glucosidase, cellobiohydrolase and endocellulase. Disease suppression was investigated in bioassays...... with test soils mixed with sand, and barley seeds inoculated with F. culmorum. After 19 days, disease severity was evaluated on the barley seedlings. Soil cellulolytic activities were measured using 4-methylumbelliferyl-labelled fluorogenic substrates, and were expressed as V-max values obtained by using...

  7. Activating RNAs associate with Mediator to enhance chromatin architecture and transcription.

    Lai, Fan; Orom, Ulf A; Cesaroni, Matteo; Beringer, Malte; Taatjes, Dylan J; Blobel, Gerd A; Shiekhattar, Ramin

    2013-02-28

    Recent advances in genomic research have revealed the existence of a large number of transcripts devoid of protein-coding potential in multiple organisms. Although the functional role for long non-coding RNAs (lncRNAs) has been best defined in epigenetic phenomena such as X-chromosome inactivation and imprinting, different classes of lncRNAs may have varied biological functions. We and others have identified a class of lncRNAs, termed ncRNA-activating (ncRNA-a), that function to activate their neighbouring genes using a cis-mediated mechanism. To define the precise mode by which such enhancer-like RNAs function, we depleted factors with known roles in transcriptional activation and assessed their role in RNA-dependent activation. Here we report that depletion of the components of the co-activator complex, Mediator, specifically and potently diminished the ncRNA-induced activation of transcription in a heterologous reporter assay using human HEK293 cells. In vivo, Mediator is recruited to ncRNA-a target genes and regulates their expression. We show that ncRNA-a interact with Mediator to regulate its chromatin localization and kinase activity towards histone H3 serine 10. The Mediator complex harbouring disease- displays diminished ability to associate with activating ncRNAs. Chromosome conformation capture confirmed the presence of DNA looping between the ncRNA-a loci and its targets. Importantly, depletion of Mediator subunits or ncRNA-a reduced the chromatin looping between the two loci. Our results identify the human Mediator complex as the transducer of activating ncRNAs and highlight the importance of Mediator and activating ncRNA association in human disease.

  8. Ddx19 links mRNA nuclear export with progression of transcription and replication and suppresses genomic instability upon DNA damage in proliferating cells.

    Hodroj, Dana; Serhal, Kamar; Maiorano, Domenico

    2017-09-03

    The DEAD-box Helicase 19 (Ddx19) gene codes for an RNA helicase involved in both mRNA (mRNA) export from the nucleus into the cytoplasm and in mRNA translation. In unperturbed cells, Ddx19 localizes in the cytoplasm and at the cytoplasmic face of the nuclear pore. Here we review recent findings related to an additional Ddx19 function in the nucleus in resolving RNA:DNA hybrids (R-loops) generated during collision between transcription and replication, and upon DNA damage. Activation of a DNA damage response pathway dependent upon the ATR kinase, a major regulator of replication fork progression, stimulates translocation of the Ddx19 protein from the cytoplasm into the nucleus. Only nuclear Ddx19 is competent to resolve R-loops, and down regulation of Ddx19 expression induces DNA double strand breaks only in proliferating cells. Overall these observations put forward Ddx19 as an important novel mediator of the crosstalk between transcription and replication.

  9. Activation of the ζ receptor 1 suppresses NMDA responses in rat retinal ganglion cells.

    Zhang, X-J; Liu, L-L; Jiang, S-X; Zhong, Y-M; Yang, X-L

    2011-03-17

    The sigma receptor 1 (σR1) has been shown to modulate the activity of several voltage- and ligand-gated channels. Using patch-clamp techniques in rat retinal slice preparations, we demonstrated that activation of σR1 by SKF10047 (SKF) or PRE-084 suppressed N-methyl-D-aspartate (NMDA) receptor-mediated current responses from both ON and OFF type ganglion cells (GCs), dose-dependently, and the effect could be blocked by the σR1 antagonist BD1047 or the σR antagonist haloperidol. The suppression by SKF of NMDA currents was abolished with pre-incubation of the G protein inhibitor GDP-β-S or the Gi/o activator mastoparan. We further explored the intracellular signaling pathway responsible for the SKF-induced suppression of NMDA responses. Application of either cAMP/the PKA inhibitor Rp-cAMP or cGMP/the PKG inhibitor KT5823 did not change the SKF-induced effect, suggesting the involvement of neither cAMP/PKA nor cGMP/PKG pathway. In contrast, suppression of NMDA responses by SKF was abolished by internal infusion of the phosphatidylinostiol-specific phospholipase C (PLC) inhibitor U73122, but not by the phosphatidylcholine-PLC inhibitor D609. SKF-induced suppression of NMDA responses was dependent on intracellular Ca2+ concentration ([Ca2+]i), as evidenced by the fact that the effect was abolished when [Ca2+]i was buffered with 10 mM BAPTA. The SKF effect was blocked by xestospongin-C/heparin, IP3 receptor antagonists, but unchanged by ryanodine/caffeine, ryanodine receptor modulators. Furthermore, application of protein kinase C inhibitors Bis IV and Gö6976 eliminated the SKF effect. These results suggest that the suppression of NMDA responses of rat retinal GCs caused by the activation of σR1 may be mediated by a distinct [Ca2+]i-dependent PLC-PKC pathway. This effect of SKF could help ameliorate malfunction of GCs caused by excessive stimulation of NMDA receptors under pathological conditions. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights

  10. Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions

    Kalaiah, Mohan Kumar; Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

    2017-01-01

    Background and Objectives The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Subjects and Methods Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using ?linear? clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the con...

  11. Benzimidazoles diminish ERE transcriptional activity and cell growth in breast cancer cells

    Payton-Stewart, Florastina [Department of Chemistry, College of Arts and Sciences, Xavier University of Louisiana, New Orleans, LA (United States); Tilghman, Syreeta L. [Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA (United States); Williams, LaKeisha G. [Division of Clinical and Administrative Sciences, College of Pharmacy Xavier University of Louisiana, New Orleans, LA (United States); Winfield, Leyte L., E-mail: lwinfield@spelman.edu [Department of Chemistry, Spelman College, Atlanta, GA (United States)

    2014-08-08

    Highlights: • The methyl-substituted benzimidazole was more effective at inhibiting growth in MDA-MB 231 cells. • The naphthyl-substituted benzimidazole was more effective at inhibiting growth in MCF-7 cells than ICI. • The benzimidazole molecules demonstrated a dose-dependent reduction in ERE transcriptional activity. • The benzimidazole molecules had binding mode in ERα and ERβ comparable to that of the co-crystallized ligand. - Abstract: Estrogen receptors (ERα and ERβ) are members of the nuclear receptor superfamily. They regulate the transcription of estrogen-responsive genes and mediate numerous estrogen related diseases (i.e., fertility, osteoporosis, cancer, etc.). As such, ERs are potentially useful targets for developing therapies and diagnostic tools for hormonally responsive human breast cancers. In this work, two benzimidazole-based sulfonamides originally designed to reduce proliferation in prostate cancer, have been evaluated for their ability to modulate growth in estrogen dependent and independent cell lines (MCF-7 and MDA-MB 231) using cell viability assays. The molecules reduced growth in MCF-7 cells, but differed in their impact on the growth of MDA-MB 231 cells. Although both molecules reduced estrogen response element (ERE) transcriptional activity in a dose dependent manner, the contrasting activity in the MDA-MB-231 cells seems to suggest that the molecules may act through alternate ER-mediated pathways. Further, the methyl analog showed modest selectivity for the ERβ receptor in an ER gene expression array panel, while the naphthyl analog did not significantly alter gene expression. The molecules were docked in the ligand binding domains of the ERα-antagonist and ERβ-agonist crystal structures to evaluate the potential of the molecules to interact with the receptors. The computational analysis complimented the results obtained in the assay of transcriptional activity and gene expression suggesting that the molecules

  12. Benzimidazoles diminish ERE transcriptional activity and cell growth in breast cancer cells

    Payton-Stewart, Florastina; Tilghman, Syreeta L.; Williams, LaKeisha G.; Winfield, Leyte L.

    2014-01-01

    Highlights: • The methyl-substituted benzimidazole was more effective at inhibiting growth in MDA-MB 231 cells. • The naphthyl-substituted benzimidazole was more effective at inhibiting growth in MCF-7 cells than ICI. • The benzimidazole molecules demonstrated a dose-dependent reduction in ERE transcriptional activity. • The benzimidazole molecules had binding mode in ERα and ERβ comparable to that of the co-crystallized ligand. - Abstract: Estrogen receptors (ERα and ERβ) are members of the nuclear receptor superfamily. They regulate the transcription of estrogen-responsive genes and mediate numerous estrogen related diseases (i.e., fertility, osteoporosis, cancer, etc.). As such, ERs are potentially useful targets for developing therapies and diagnostic tools for hormonally responsive human breast cancers. In this work, two benzimidazole-based sulfonamides originally designed to reduce proliferation in prostate cancer, have been evaluated for their ability to modulate growth in estrogen dependent and independent cell lines (MCF-7 and MDA-MB 231) using cell viability assays. The molecules reduced growth in MCF-7 cells, but differed in their impact on the growth of MDA-MB 231 cells. Although both molecules reduced estrogen response element (ERE) transcriptional activity in a dose dependent manner, the contrasting activity in the MDA-MB-231 cells seems to suggest that the molecules may act through alternate ER-mediated pathways. Further, the methyl analog showed modest selectivity for the ERβ receptor in an ER gene expression array panel, while the naphthyl analog did not significantly alter gene expression. The molecules were docked in the ligand binding domains of the ERα-antagonist and ERβ-agonist crystal structures to evaluate the potential of the molecules to interact with the receptors. The computational analysis complimented the results obtained in the assay of transcriptional activity and gene expression suggesting that the molecules

  13. Age-dependent regulation of ERF-VII transcription factor activity in Arabidopsis thaliana.

    Giuntoli, Beatrice; Shukla, Vinay; Maggiorelli, Federica; Giorgi, Federico M; Lombardi, Lara; Perata, Pierdomenico; Licausi, Francesco

    2017-10-01

    The Group VII Ethylene Responsive Factors (ERFs-VII) RAP2.2 and RAP2.12 have been mainly characterized with regard to their contribution as activators of fermentation in plants. However, transcriptional changes measured in conditions that stabilize these transcription factors exceed the mere activation of this biochemical pathway, implying additional roles performed by the ERF-VIIs in other processes. We evaluated gene expression in transgenic Arabidopsis lines expressing a stabilized form of RAP2.12, or hampered in ERF-VII activity, and identified genes affected by this transcriptional regulator and its homologs, including some involved in oxidative stress response, which are not universally induced under anaerobic conditions. The contribution of the ERF-VIIs in regulating this set of genes in response to chemically induced or submergence-stimulated mitochondria malfunctioning was found to depend on the plant developmental stage. A similar age-dependent mechanism also restrained ERF-VII activity upon the core-hypoxic genes, independently of the N-end rule pathway, which is accounted for the control of the anaerobic response. To conclude, this study shed new light on a dual role of ERF-VII proteins under submergence: as positive regulators of the hypoxic response and as repressors of oxidative-stress related genes, depending on the developmental stage at which plants are challenged by stress conditions. © 2017 John Wiley & Sons Ltd.

  14. ERalpha and ERbeta expression and transcriptional activity are differentially regulated by HDAC inhibitors

    Duong, Vanessa; Licznar, Anne; Margueron, Raphaël; Boulle, Nathalie; Busson, Muriel; Lacroix, Matthieu; Katzenellenbogen, Benita S.; Cavaillès, Vincent; Lazennec, Gwendal

    2006-01-01

    The proliferative action of ERα largely accounts for the carcinogenic activity of estrogens. By contrast, recent data show that ERβ displays tumor-suppressor properties, thus supporting the interest to identify compounds which could increase its activity. Here, we show that histone deacetylase inhibitors (HDI) up-regulated ERβ protein levels, whereas it decreased ERα expression. Part of this regulation took place at the mRNA level through a mechanism independent of de novo protein synthesis. In addition, we found that, in various cancer cells, the treatment with different HDI enhanced the ligand-dependent activity of ERβ more strongly than that of ERα. On the other hand, in MDA-MB231 and HeLa cells, the expression of ERs modified the transcriptional response to HDI. The use of deletion mutants of both receptors demonstrated that AF1 domain of the receptors was required. Finally, we show that ERβ expression led to a dramatic increased in the antiproliferative activity of HDI, which correlated with a modification of the transcription of genes involved in cell cycle control by HDI. Altogether, these data demonstrate that the interference of ERβ and HDAC on the control of transcription and cell proliferation constitute a promising approach for cancer therapy. PMID:16158045

  15. SUMOylation regulates the transcriptional repression activity of FOG-2 and its association with GATA-4.

    Perdomo, José; Jiang, Xing-Mai; Carter, Daniel R; Khachigian, Levon M; Chong, Beng H

    2012-01-01

    Friend of GATA 2 (FOG-2), a co-factor of several GATA transcription factors (GATA-4, -5 and 6), is a critical regulator of coronary vessel formation and heart morphogenesis. Here we demonstrate that FOG-2 is SUMOylated and that this modification modulates its transcriptional activity. FOG-2 SUMOylation occurs at four lysine residues (K324, 471, 915, 955) [corrected]. Three of these residues are part of the characteristic SUMO consensus site (ψKXE), while K955 is found in the less frequent TKXE motif. Absence of SUMOylation did not affect FOG-2's nuclear localization. However, mutation of the FOG-2 SUMOylation sites, or de-SUMOylation, with SENP-1 or SENP-8 resulted in stronger transcriptional repression activity in both heterologous cells and cardiomyocytes. Conversely, increased FOG-2 SUMOylation by overexpression of SUMO-1 or expression of a SUMO-1-FOG-2 fusion protein rendered FOG-2 incapable of repressing GATA-4-mediated activation of the B-type natriuretic peptide (BNP) promoter. Moreover, we demonstrate both increased interaction between a FOG-2 SUMO mutant and GATA-4 and enhanced SUMOylation of wild-type FOG-2 by co-expression of GATA-4. These data suggest a new dynamics in which GATA-4 may alter the activity of FOG-2 by influencing its SUMOylation status.

  16. The flavonoid fisetin promotes osteoblasts differentiation through Runx2 transcriptional activity.

    Léotoing, Laurent; Davicco, Marie-Jeanne; Lebecque, Patrice; Wittrant, Yohann; Coxam, Véronique

    2014-06-01

    Flavonoids represent a group of polyphenolic compounds commonly found in daily nutrition with proven health benefits. Among this group, the flavonol fisetin has been previously shown to protect bone by repressing osteoclast differentiation. In the present study, we investigated the role of fisetin in regulating osteoblasts physiology. In vivo mice treated with LPSs exhibited osteoporosis features associated with a dramatic repression of osteoblast marker expression. In this model, inhibition of osteocalcin and type I collagen alpha 1 transcription was partially countered by a daily consumption of fisetin. Interestingly, in vitro, fisetin promoted both osteoblast alkaline phosphatase activity and mineralization process. To decipher how fisetin may exert its positive effect on osteoblastogenesis, we analyzed its ability to control the runt-related transcription factor 2 (Runx2), a key organizer in developing and maturing osteoblasts. While fisetin did not impact Runx2 mRNA and protein levels, it upregulated its transcriptional activity. Actually, fisetin stimulated the luciferase activity of a reporter plasmid driven by the osteocalcin gene promoter that contains Runx2 binding sites and promoted the mRNA expression of osteocalcin and type I collagen alpha 1 targets. Bone sparing properties of fisetin also rely on its positive influence on osteoblast differentiation and activity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. SUMOylation regulates the transcriptional repression activity of FOG-2 and its association with GATA-4.

    José Perdomo

    Full Text Available Friend of GATA 2 (FOG-2, a co-factor of several GATA transcription factors (GATA-4, -5 and 6, is a critical regulator of coronary vessel formation and heart morphogenesis. Here we demonstrate that FOG-2 is SUMOylated and that this modification modulates its transcriptional activity. FOG-2 SUMOylation occurs at four lysine residues (K324, 471, 915, 955 [corrected]. Three of these residues are part of the characteristic SUMO consensus site (ψKXE, while K955 is found in the less frequent TKXE motif. Absence of SUMOylation did not affect FOG-2's nuclear localization. However, mutation of the FOG-2 SUMOylation sites, or de-SUMOylation, with SENP-1 or SENP-8 resulted in stronger transcriptional repression activity in both heterologous cells and cardiomyocytes. Conversely, increased FOG-2 SUMOylation by overexpression of SUMO-1 or expression of a SUMO-1-FOG-2 fusion protein rendered FOG-2 incapable of repressing GATA-4-mediated activation of the B-type natriuretic peptide (BNP promoter. Moreover, we demonstrate both increased interaction between a FOG-2 SUMO mutant and GATA-4 and enhanced SUMOylation of wild-type FOG-2 by co-expression of GATA-4. These data suggest a new dynamics in which GATA-4 may alter the activity of FOG-2 by influencing its SUMOylation status.

  18. A light- and calcium-gated transcription factor for imaging and manipulating activated neurons.

    Wang, Wenjing; Wildes, Craig P; Pattarabanjird, Tanyaporn; Sanchez, Mateo I; Glober, Gordon F; Matthews, Gillian A; Tye, Kay M; Ting, Alice Y

    2017-09-01

    Activity remodels neurons, altering their molecular, structural, and electrical characteristics. To enable the selective characterization and manipulation of these neurons, we present FLARE, an engineered transcription factor that drives expression of fluorescent proteins, opsins, and other genetically encoded tools only in the subset of neurons that experienced activity during a user-defined time window. FLARE senses the coincidence of elevated cytosolic calcium and externally applied blue light, which together produce translocation of a membrane-anchored transcription factor to the nucleus to drive expression of any transgene. In cultured rat neurons, FLARE gives a light-to-dark signal ratio of 120 and a high- to low-calcium signal ratio of 10 after 10 min of stimulation. Opsin expression permitted functional manipulation of FLARE-marked neurons. In adult mice, FLARE also gave light- and motor-activity-dependent transcription in the cortex. Due to its modular design, minute-scale temporal resolution, and minimal dark-state leak, FLARE should be useful for the study of activity-dependent processes in neurons and other cells that signal with calcium.

  19. G-actin sequestering protein thymosin-β4 regulates the activity of myocardin-related transcription factor

    Morita, Tsuyoshi; Hayashi, Ken’ichiro

    2013-01-01

    Highlights: •Tβ4 competed with MRTF-A for G-actin binding. •Tβ4 activated the MRTF–SRF signaling pathway. •Tβ4 increased the endogenous expression of SRF-dependent genes. -- Abstract: Myocardin-related transcription factors (MRTFs) are robust coactivators of serum response factor (SRF). MRTFs contain three copies of the RPEL motif at their N-terminus, and they bind to monomeric globular actin (G-actin). Previous studies illustrate that G-actin binding inhibits MRTF activity by preventing the MRTFs nuclear accumulation. In the living cells, the majority of G-actin is sequestered by G-actin binding proteins that prevent spontaneous actin polymerization. Here, we demonstrate that the most abundant G-actin sequestering protein thymosin-β4 (Tβ4) was involved in the regulation of subcellular localization and activity of MRTF-A. Tβ4 competed with MRTF-A for G-actin binding; thus, interfering with G-actin–MRTF-A complex formation. Tβ4 overexpression induced the MRTF-A nuclear accumulation and activation of MRTF–SRF signaling. The activation rate of MRTF-A by the Tβ4 mutant L17A, whose affinity for G-actin is very low, was lower than that by wild-type Tβ4. In contrast, the β-actin mutant 3DA, which has a lower affinity for Tβ4, more effectively suppressed MRTF-A activity than wild-type β-actin. Furthermore, ectopic Tβ4 increased the endogenous expression of SRF-dependent actin cytoskeletal genes. Thus, Tβ4 is an important MRTF regulator that controls the G-actin–MRTFs interaction

  20. G-actin sequestering protein thymosin-β4 regulates the activity of myocardin-related transcription factor

    Morita, Tsuyoshi, E-mail: tsuyo@nbiochem.med.osaka-u.ac.jp; Hayashi, Ken’ichiro

    2013-08-02

    Highlights: •Tβ4 competed with MRTF-A for G-actin binding. •Tβ4 activated the MRTF–SRF signaling pathway. •Tβ4 increased the endogenous expression of SRF-dependent genes. -- Abstract: Myocardin-related transcription factors (MRTFs) are robust coactivators of serum response factor (SRF). MRTFs contain three copies of the RPEL motif at their N-terminus, and they bind to monomeric globular actin (G-actin). Previous studies illustrate that G-actin binding inhibits MRTF activity by preventing the MRTFs nuclear accumulation. In the living cells, the majority of G-actin is sequestered by G-actin binding proteins that prevent spontaneous actin polymerization. Here, we demonstrate that the most abundant G-actin sequestering protein thymosin-β4 (Tβ4) was involved in the regulation of subcellular localization and activity of MRTF-A. Tβ4 competed with MRTF-A for G-actin binding; thus, interfering with G-actin–MRTF-A complex formation. Tβ4 overexpression induced the MRTF-A nuclear accumulation and activation of MRTF–SRF signaling. The activation rate of MRTF-A by the Tβ4 mutant L17A, whose affinity for G-actin is very low, was lower than that by wild-type Tβ4. In contrast, the β-actin mutant 3DA, which has a lower affinity for Tβ4, more effectively suppressed MRTF-A activity than wild-type β-actin. Furthermore, ectopic Tβ4 increased the endogenous expression of SRF-dependent actin cytoskeletal genes. Thus, Tβ4 is an important MRTF regulator that controls the G-actin–MRTFs interaction.

  1. Fisetin inhibits epidermal growth factor-induced migration of ARPE-19 cells by suppression of AKT activation and Sp1-dependent MMP-9 expression.

    Lin, Hung-Yu; Chen, Yong-Syuan; Wang, Kai; Chien, Hsiang-Wen; Hsieh, Yi-Hsien; Yang, Shun-Fa

    2017-01-01

    Proliferative vitreoretinopathy (PVR) can result in abnormal migration of RPE cells. Fisetin is a naturally occurring compound that has been reported to have antitumor effects, but its effects on epidermal growth factor (EGF)-induced cell migration and the underlying mechanisms remain unclear. Effects of fisetin on EGF-induced cell viability and migration were examined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and in vitro migration assays. Reverse transcription-PCR (RT-PCR) and immunoblotting were performed to evaluate matrix metallopeptidase-9 (MMP-9) expression and activation of specificity protein-1 (Sp1) and protein kinase B (AKT) in ARPE-19 cells treated with EGF and with or without fisetin. Luciferase and chromatin immunoprecipitation (ChIP) assays were performed to examine Sp1 transcription activity and MMP-9 binding activity. Fisetin did not affect ARPE-19 cell viability and significantly inhibited the EGF-induced migration capacity of ARPE-19 cells. Furthermore, fisetin exerted an antimigratory effect and suppressed MMP-9 mRNA and protein expression. Treatment with EGF induced phosphorylation of AKT and expression of MMP-9 and Sp1. Fisetin combined with LY294002 (an inhibitor of AKT) prevented the EGF-induced migration involved in downregulation of Sp1 and MMP-9 expression. Luciferase and ChIP assays suggested that fisetin remarkably decreased the EGF-induced transcription activity of MMP-9 and Sp1 and inhibited EGF-mediated Sp1 from directly binding to the MMP-9 promoter in ARPE-19 cells. Fisetin inhibited EGF-induced cell migration via modulation of AKT/Sp1-dependent MMP-9 transcriptional activity. Therefore, fisetin may be a potential agent in the treatment of migratory PVR diseases.

  2. Two transcriptional activators of N-acetylserotonin O-methyltransferase 2 and melatonin biosynthesis in cassava.

    Wei, Yunxie; Liu, Guoyin; Bai, Yujing; Xia, Feiyu; He, Chaozu; Shi, Haitao; Foyer, Christine

    2017-10-13

    Similar to the situation in animals, melatonin biosynthesis is regulated by four sequential enzymatic steps in plants. Although the melatonin synthesis genes have been identified in various plants, the upstream transcription factors of them remain unknown. In this study on cassava (Manihot esculenta), we found that MeWRKY79 and heat-shock transcription factor 20 (MeHsf20) targeted the W-box and the heat-stress elements (HSEs) in the promoter of N-acetylserotonin O-methyltransferase 2 (MeASMT2), respectively. The interaction between MeWRKY79, MeHsf20, and the MeASMT2 promoter was evidenced by the activation of promoter activity and chromatin immunoprecipitation (ChIP) in cassava protoplasts, and by an in vitro electrophoretic mobility shift assay (EMSA). The transcripts of MeWRKY79, MeHsf20, and MeASMT2 were all regulated by a 22-amino acid flagellin peptide (flg22) and by Xanthomonas axonopodis pv manihotis (Xam). In common with the phenotype of MeASMT2, transient expression of MeWRKY79 and MeHsf20 in Nicotiana benthamiana leaves conferred improved disease resistance. Through virus-induced gene silencing (VIGS) in cassava, we found that MeWRKY79- and MeHsf20-silenced plants showed lower transcripts of MeASMT2 and less accumulation of melatonin, which resulted in disease sensitivity that could be reversed by exogenous melatonin. Taken together, these results indicate that MeASMT2 is a target of MeWRKY79 and MeHsf20 in plant disease resistance. This study identifies novel upstream transcription factors of melatonin synthesis genes in cassava, thus extending our knowledge of the complex modulation of melatonin synthesis in plant defense. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  3. A central regulatory system largely controls transcriptional activation and repression responses to phosphate starvation in Arabidopsis.

    Regla Bustos

    2010-09-01

    Full Text Available Plants respond to different stresses by inducing or repressing transcription of partially overlapping sets of genes. In Arabidopsis, the PHR1 transcription factor (TF has an important role in the control of phosphate (Pi starvation stress responses. Using transcriptomic analysis of Pi starvation in phr1, and phr1 phr1-like (phl1 mutants and in wild type plants, we show that PHR1 in conjunction with PHL1 controls most transcriptional activation and repression responses to phosphate starvation, regardless of the Pi starvation specificity of these responses. Induced genes are enriched in PHR1 binding sequences (P1BS in their promoters, whereas repressed genes do not show such enrichment, suggesting that PHR1(-like control of transcriptional repression responses is indirect. In agreement with this, transcriptomic analysis of a transgenic plant expressing PHR1 fused to the hormone ligand domain of the glucocorticoid receptor showed that PHR1 direct targets (i.e., displaying altered expression after GR:PHR1 activation by dexamethasone in the presence of cycloheximide corresponded largely to Pi starvation-induced genes that are highly enriched in P1BS. A minimal promoter containing a multimerised P1BS recapitulates Pi starvation-specific responsiveness. Likewise, mutation of P1BS in the promoter of two Pi starvation-responsive genes impaired their responsiveness to Pi starvation, but not to other stress types. Phylogenetic footprinting confirmed the importance of P1BS and PHR1 in Pi starvation responsiveness and indicated that P1BS acts in concert with other cis motifs. All together, our data show that PHR1 and PHL1 are partially redundant TF acting as central integrators of Pi starvation responses, both specific and generic. In addition, they indicate that transcriptional repression responses are an integral part of adaptive responses to stress.

  4. Generation of knockout rabbits using transcription activator-like effector nucleases

    Yu Wang

    2014-01-01

    Full Text Available Zinc-finger nucleases and transcription activator-like effector nucleases are novel gene-editing platforms contributing to redefine the boundaries of modern biological research. They are composed of a non-specific cleavage domain and a tailor made DNA-binding module, which enables a broad range of genetic modifications by inducing efficient DNA double-strand breaks at desired loci. Among other remarkable uses, these nucleases have been employed to produce gene knockouts in mid-size and large animals, such as rabbits and pigs, respectively. This approach is cost effective, relatively quick, and can produce invaluable models for human disease studies, biotechnology or agricultural purposes. Here we describe a protocol for the efficient generation of knockout rabbits using transcription activator-like effector nucleases, and a perspective of the field.

  5. Generation of knockout rabbits using transcription activator-like effector nucleases.

    Wang, Yu; Fan, Nana; Song, Jun; Zhong, Juan; Guo, Xiaogang; Tian, Weihua; Zhang, Quanjun; Cui, Fenggong; Li, Li; Newsome, Philip N; Frampton, Jon; Esteban, Miguel A; Lai, Liangxue

    2014-01-01

    Zinc-finger nucleases and transcription activator-like effector nucleases are novel gene-editing platforms contributing to redefine the boundaries of modern biological research. They are composed of a non-specific cleavage domain and a tailor made DNA-binding module, which enables a broad range of genetic modifications by inducing efficient DNA double-strand breaks at desired loci. Among other remarkable uses, these nucleases have been employed to produce gene knockouts in mid-size and large animals, such as rabbits and pigs, respectively. This approach is cost effective, relatively quick, and can produce invaluable models for human disease studies, biotechnology or agricultural purposes. Here we describe a protocol for the efficient generation of knockout rabbits using transcription activator-like effector nucleases, and a perspective of the field.

  6. Thyroid hormone and retinoic acid nuclear receptors: specific ligand-activated transcription factors

    Brtko, J.

    1998-01-01

    Transcriptional regulation by both the thyroid hormone and the vitamin A-derived 'retinoid hormones' is a critical component in controlling many aspects of higher vertebrate development and metabolism. Their functions are mediated by nuclear receptors, which comprise a large super-family of ligand-inducible transcription factors. Both the thyroid hormone and the retinoids are involved in a complex arrangement of physiological and development responses in many tissues of higher vertebrates. The functions of 3,5,3'-triiodothyronine (T 3 ), the thyromimetically active metabolite of thyroxine as well as all-trans retinoic acid, the biologically active vitamin A metabolite are mediated by nuclear receptor proteins that are members of the steroid/thyroid/retinoid hormone receptor family. The functions of all members of the receptor super family are discussed. (authors)

  7. Mechanisms for type-II vitellogenesis-inhibiting hormone suppression of vitellogenin transcription in shrimp hepatopancreas: Crosstalk of GC/cGMP pathway with different MAPK-dependent cascades.

    Chen, Ting; Ren, Chunhua; Jiang, Xiao; Zhang, Lvping; Li, Hongmei; Huang, Wen; Hu, Chaoqun

    2018-01-01

    Vitellogenesis is the process of yolk formation via accumulating vitellin (Vn) with nutrients in the oocytes. Expression of vitellogenin (Vg), the precursor of Vn, is one of the indicators for the start of vitellogenesis. In Pacific white shrimp (Litopenaeus vannamei), the type-II vitellogenesis-inhibiting hormone (VIH-2) effectively suppresses hepatopancreatic Vg mRNA expression. In this study, we demonstrate the increasing transcript levels of hepatopancreatic Vg during L. vannamei ovarian development, suggesting that the hepatopancreas-derived Vg/Vn may also contribute to vitellogenesis in this species. Using a combination of in vivo injections and in vitro primary cell cultures, we provide evidences that the inhibition of VIH-2 on hepatopancreatic Vg gene expression is mediated through a functional coupling of the GC/cGMP pathway with different MAPK-dependent cascades in female shrimp. In VIH-2 signaling, the NO-independent GC/cGMP/PKG cascades were upstream of the MAPKs. Activations of the MAPK signal by VIH-2 include the phosphorylation of JNK and the mRNA/protein expression of P38MAPK. Additionally, the cAMP/PKA pathway is another positive intracellular signal for hepatopancreatic Vg mRNA expression but is independent of its VIH-2 regulation. Our findings establish a model for the signal transduction mechanism of Vg regulation by VIH and shed light on the biological functions and signaling of the CHH family in crustaceans.

  8. Activation-induced deoxycytidine deaminase (AID) co-transcriptional scanning at single-molecule resolution

    Senavirathne, Gayan; Bertram, Jeffrey G.; Jaszczur, Malgorzata; Chaurasiya, Kathy R.; Pham, Phuong; Mak, Chi H.; Goodman, Myron F.; Rueda, David

    2015-12-01

    Activation-induced deoxycytidine deaminase (AID) generates antibody diversity in B cells by initiating somatic hypermutation (SHM) and class-switch recombination (CSR) during transcription of immunoglobulin variable (IgV) and switch region (IgS) DNA. Using single-molecule FRET, we show that AID binds to transcribed dsDNA and translocates unidirectionally in concert with RNA polymerase (RNAP) on moving transcription bubbles, while increasing the fraction of stalled bubbles. AID scans randomly when constrained in an 8 nt model bubble. When unconstrained on single-stranded (ss) DNA, AID moves in random bidirectional short slides/hops over the entire molecule while remaining bound for ~5 min. Our analysis distinguishes dynamic scanning from static ssDNA creasing. That AID alone can track along with RNAP during transcription and scan within stalled transcription bubbles suggests a mechanism by which AID can initiate SHM and CSR when properly regulated, yet when unregulated can access non-Ig genes and cause cancer.

  9. Differential Transcriptional Activation of Genes Encoding Soluble Methane Monooxygenase in a Facultative Versus an Obligate Methanotroph.

    Smirnova, Angela V; Dunfield, Peter F

    2018-03-06

    Methanotrophs are a specialized group of bacteria that can utilize methane (CH₄) as a sole energy source. A key enzyme responsible for methane oxidation is methane monooxygenase (MMO), of either a soluble, cytoplasmic type (sMMO), or a particulate, membrane-bound type (pMMO). Methylocella silvestris BL2 and Methyloferula stellata AR4 are closely related methanotroph species that oxidize methane via sMMO only. However, Methyloferula stellata is an obligate methanotroph, while Methylocella silvestris is a facultative methanotroph able to grow on several multicarbon substrates in addition to methane. We constructed transcriptional fusions of the mmo promoters of Methyloferula stellata and Methylocella silvestris to a promoterless gfp in order to compare their transcriptional regulation in response to different growth substrates, in the genetic background of both organisms. The following patterns were observed: (1) The mmo promoter of the facultative methanotroph Methylocella silvestris was either transcriptionally downregulated or repressed by any growth substrate other than methane in the genetic background of Methylocella silvetris ; (2) Growth on methane alone upregulated the mmo promoter of Methylocella silvetris in its native background but not in the obligate methanotroph Methyloferula stellata ; (3) The mmo promoter of Methyloferula stellata was constitutive in both organisms regardless of the growth substrate, but with much lower promoter activity than the mmo promoter of Methylocella silvetris . These results support a conclusion that a different mode of transcriptional regulation of sMMO contributes to the facultative lifestyle of Methylocella silvetris compared to the obligate methanotroph Methyloferula stellata .

  10. Differential Transcriptional Activation of Genes Encoding Soluble Methane Monooxygenase in a Facultative Versus an Obligate Methanotroph

    Angela V. Smirnova

    2018-03-01

    Full Text Available Methanotrophs are a specialized group of bacteria that can utilize methane (CH4 as a sole energy source. A key enzyme responsible for methane oxidation is methane monooxygenase (MMO, of either a soluble, cytoplasmic type (sMMO, or a particulate, membrane-bound type (pMMO. Methylocella silvestris BL2 and Methyloferula stellata AR4 are closely related methanotroph species that oxidize methane via sMMO only. However, Methyloferula stellata is an obligate methanotroph, while Methylocella silvestris is a facultative methanotroph able to grow on several multicarbon substrates in addition to methane. We constructed transcriptional fusions of the mmo promoters of Methyloferula stellata and Methylocella silvestris to a promoterless gfp in order to compare their transcriptional regulation in response to different growth substrates, in the genetic background of both organisms. The following patterns were observed: (1 The mmo promoter of the facultative methanotroph Methylocella silvestris was either transcriptionally downregulated or repressed by any growth substrate other than methane in the genetic background of Methylocella silvetris; (2 Growth on methane alone upregulated the mmo promoter of Methylocella silvetris in its native background but not in the obligate methanotroph Methyloferula stellata; (3 The mmo promoter of Methyloferula stellata was constitutive in both organisms regardless of the growth substrate, but with much lower promoter activity than the mmo promoter of Methylocella silvetris. These results support a conclusion that a different mode of transcriptional regulation of sMMO contributes to the facultative lifestyle of Methylocella silvetris compared to the obligate methanotroph Methyloferula stellata.

  11. Nicotine suppresses the neurotoxicity by MPP+/MPTP through activating α7nAChR/PI3K/Trx-1 and suppressing ER stress.

    Cai, Yanxue; Zhang, Xianwen; Zhou, Xiaoshuang; Wu, Xiaoli; Li, Yanhui; Yao, Jianhua; Bai, Jie

    2017-03-01

    Parkinson's disease (PD) is a neurodegenerative disease. Nicotine has been reported to have the role in preventing Parkinson's disease. However, its mechanism is still unclear. In present study we found that nicotine suppressed 1-methyl-4-phenylpyridinium ion(MPP + ) toxicity in PC12 cells by MTT assay. The expression of thioredoxin-1(Trx-1) was decreased by MPP + , which was restored by nicotine. The nicotine suppressed expressions of Glucose-regulated protein 78(GRP78/Bip) and C/EBP homologous protein (CHOP) induced by MPP + . The methyllycaconitine (MLA), the inhibitor of α7nAChR and LY294002, the inhibitor of phosphatidylinositol 3-kinase (PI3K) blocked the suppressions of above molecules, respectively. Consistently, pretreatment with nicotine ameliorated the motor ability, restored the declines of Trx-1 and tyrosine hydroxylase (TH), and suppressed the expressions of Bip and CHOP induced by 1-Methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice. Our results suggest that nicotine plays role in resisting MPP + /MPTP neurotoxicity through activating the α7nAChR/PI3K/Trx-1 pathway and suppressing ER stress. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Androgen receptor activation integrates complex transcriptional effects in osteoblasts, involving the growth factors TGF-β and IGF-I, and transcription factor C/EBPδ.

    McCarthy, Thomas L; Centrella, Michael

    2015-11-15

    Osteoblasts respond to many growth factors including IGF-I and TGF-β, which themselves are sensitive to other bone growth regulators. Here we show that IGF-I gene promoter activity in prostaglandin E2 (PGE2) induced osteoblasts is suppressed by dihydrotestosterone (DHT) through an essential C/EBP response element (RE) in exon 1 of the igf1 gene. Inhibition by DHT fails to occur when the androgen receptor (AR) gene is mutated within its DNA binding domain. Correspondingly, DHT activated AR inhibits gene transactivation by C/EBPδ, and transgenic C/EBPδ expression inhibits AR activity. Inhibition by DHT persists when upstream Smad and Runx REs in the IGF-I gene promoter are mutated. TGF-β also enhances IGF-I gene promoter activity, although modestly relative to PGE2, and independently of the C/EBP, Smad, or Runx REs. Still, DHT suppresses TGF-β induced IGF-I promoter activity, but not its effects on DNA or collagen synthesis. Notably, DHT suppresses plasminogen activator inhibitor gene promoter activity, but synergistically increases Smad dependent gene promoter activity in TGF-β induced cells, which are differentially sensitive to AR mutations and the AR co-regulator ARA55. Finally, although the PGE2 sensitive C/EBP RE in the igf1 gene is not essential for basal TGF-β induction, C/EBPδ activity through this site is potently enhanced by TGF-β. Thus DHT suppresses the PGE2 and TGF-β induced IGF-I gene promoter and differentiates other aspects of TGF-β activity in osteoblasts. Our results extend the complex interactions among local and systemic bone growth regulators to DHT, and predict complications from anabolic steroid use in other DHT sensitive tissues. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    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.

  14. Generation of knockout rabbits using transcription activator-like effector nucleases

    Wang, Yu; Fan, Nana; Song, Jun; Zhong, Juan; Guo, Xiaogang; Tian, Weihua; Zhang, Quanjun; Cui, Fenggong; Li, Li; Newsome, Philip N; Frampton, Jon; Esteban, Miguel A; Lai, Liangxue

    2014-01-01

    Zinc-finger nucleases and transcription activator-like effector nucleases are novel gene-editing platforms contributing to redefine the boundaries of modern biological research. They are composed of a non-specific cleavage domain and a tailor made DNA-binding module, which enables a broad range of genetic modifications by inducing efficient DNA double-strand breaks at desired loci. Among other remarkable uses, these nucleases have been employed to produce gene knockouts in mid-size and large ...

  15. The metazoan Mediator co-activator complex as an integrative hub for transcriptional regulation

    Malik, Sohail; Roeder, Robert G.

    2010-01-01

    The Mediator is an evolutionarily conserved, multiprotein complex that is a key regulator of protein-coding genes. In metazoan cells, multiple pathways that are responsible for homeostasis, cell growth and differentiation converge on the Mediator through transcriptional activators and repressors that target one or more of the almost 30 subunits of this complex. Besides interacting directly with RNA polymerase II, Mediator has multiple functions and can interact with and coordinate the action ...

  16. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    Radhakrishnan Sridhar

    2010-05-01

    Full Text Available Abstract Background Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene, a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. Methods We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Results Resveratrol (100-150 μM exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G0/G1-S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. Conclusions For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and

  17. Resveratrol suppresses IGF-1 induced human colon cancer cell proliferation and elevates apoptosis via suppression of IGF-1R/Wnt and activation of p53 signaling pathways

    Vanamala, Jairam; Reddivari, Lavanya; Radhakrishnan, Sridhar; Tarver, Chris

    2010-01-01

    Obesity is a global phenomenon and is associated with various types of cancer, including colon cancer. There is a growing interest for safe and effective bioactive compounds that suppress the risk for obesity-promoted colon cancer. Resveratrol (trans-3, 4', 5,-trihydroxystilbene), a stilbenoid found in the skin of red grapes and peanuts suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms, however, resveratrol effects on obesity-promoted colon cancer are not clearly established. We investigated the anti-proliferative effects of resveratrol on HT-29 and SW480 human colon cancer cells in the presence and absence of insulin like growth factor-1 (IGF-1; elevated during obesity) and elucidated the mechanisms of action using IGF-1R siRNA in HT-29 cells which represents advanced colon carcinogenesis. Resveratrol (100-150 μM) exhibited anti-proliferative properties in HT-29 cells even after IGF-1 exposure by arresting G 0 /G 1 -S phase cell cycle progression through p27 stimulation and cyclin D1 suppression. Treatment with resveratrol suppressed IGF-1R protein levels and concurrently attenuated the downstream Akt/Wnt signaling pathways that play a critical role in cell proliferation. Targeted suppression of IGF-1R using IGF-1R siRNA also affected these signaling pathways in a similar manner. Resveratrol treatment induced apoptosis by activating tumor suppressor p53 protein, whereas IGF-1R siRNA treatment did not affect apoptosis. Our data suggests that resveratrol not only suppresses cell proliferation by inhibiting IGF-1R and its downstream signaling pathways similar to that of IGF-1R siRNA but also enhances apoptosis via activation of the p53 pathway. For the first time, we report that resveratrol suppresses colon cancer cell proliferation and elevates apoptosis even in the presence of IGF-1 via suppression of IGF-1R/Akt/Wnt signaling pathways and activation of p53, suggesting its potential role as a

  18. Atf4 regulates chondrocyte proliferation and differentiation during endochondral ossification by activating Ihh transcription.

    Wang, Weiguang; Lian, Na; Li, Lingzhen; Moss, Heather E; Wang, Weixi; Perrien, Daniel S; Elefteriou, Florent; Yang, Xiangli

    2009-12-01

    Activating transcription factor 4 (Atf4) is a leucine-zipper-containing protein of the cAMP response element-binding protein (CREB) family. Ablation of Atf4 (Atf4(-/-)) in mice leads to severe skeletal defects, including delayed ossification and low bone mass, short stature and short limbs. Atf4 is expressed in proliferative and prehypertrophic growth plate chondrocytes, suggesting an autonomous function of Atf4 in chondrocytes during endochondral ossification. In Atf4(-/-) growth plate, the typical columnar structure of proliferative chondrocytes is disturbed. The proliferative zone is shortened, whereas the hypertrophic zone is transiently expanded. The expression of Indian hedgehog (Ihh) is markedly decreased, whereas the expression of other chondrocyte marker genes, such as type II collagen (Col2a1), PTH/PTHrP receptor (Pth1r) and type X collagen (Col10a1), is normal. Furthermore, forced expression of Atf4 in chondrocytes induces endogenous Ihh mRNA, and Atf4 directly binds to the Ihh promoter and activates its transcription. Supporting these findings, reactivation of Hh signaling pharmacologically in mouse limb explants corrects the Atf4(-/-) chondrocyte proliferation and short limb phenotypes. This study thus identifies Atf4 as a novel transcriptional activator of Ihh in chondrocytes that paces longitudinal bone growth by controlling growth plate chondrocyte proliferation and differentiation.

  19. Presence and transcriptional activity of anaerobic fungi in agricultural biogas plants.

    Dollhofer, Veronika; Callaghan, Tony M; Griffith, Gareth W; Lebuhn, Michael; Bauer, Johann

    2017-07-01

    Bioaugmentation with anaerobic fungi (AF) is promising for improved biogas generation from lignocelluloses-rich substrates. However, before implementing AF into biogas processes it is necessary to investigate their natural occurrence, community structure and transcriptional activity in agricultural biogas plants. Thus, AF were detected with three specific PCR based methods: (i) Copies of their 18S genes were found in 7 of 10 biogas plants. (ii) Transcripts of a GH5 endoglucanase gene were present at low level in two digesters, indicating transcriptional cellulolytic activity of AF. (iii) Phylogeny of the AF-community was inferred with the 28S gene. A new Piromyces species was isolated from a PCR-positive digester. Evidence for AF was only found in biogas plants operated with high proportions of animal feces. Thus, AF were most likely transferred into digesters with animal derived substrates. Additionally, high process temperatures in combination with long retention times seemed to impede AF survival and activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The metal-responsive transcription factor-1 contributes to HIF-1 activation during hypoxic stress

    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

  1. Hypoxia induces cyclophilin B through the activation of transcription factor 6 in gastric adenocarcinoma cells.

    Jeong, Kwon; Kim, Kiyoon; Kim, Hunsung; Oh, Yoojung; Kim, Seong-Jin; Jo, Yunhee; Choe, Wonchae

    2015-06-01

    Hypoxia is an important form of physiological stress that induces cell death, due to the resulting endoplasmic reticulum (ER) stress, particularly in solid tumors. Although previous studies have indicated that cyclophilin B (CypB) plays a role in ER stress, there is currently no direct information supporting the mechanism of CypB involvement under hypoxic conditions. However, it has previously been demonstrated that ER stress positively regulates the expression of CypB. In the present study, it was demonstrated that CypB is transcriptionally regulated by hypoxia-mediated activation of transcription factor 6 (ATF6), an ER stress transcription factor. Subsequently, the effects of ATF6 on CypB promoter activity were investigated and an ATF6-responsive region in the promoter was identified. Hypoxia and ATF6 expression each increased CypB promoter activity. Collectively, these results demonstrate that ATF6 positively regulates the expression of CypB by binding to an ATF6-responsive region in the promoter, which may play an important role in the attenuation of apoptosis in the adaption to hypoxia. These results suggest that CypB may be a key molecule in the adaptation of cells to hypoxic conditions.

  2. Low prevalence of transcriptionally active human papilloma virus in Indian patients with HNSCC and leukoplakia.

    Bhosale, Priyanka G; Pandey, Manishkumar; Desai, Rajiv S; Patil, Asawari; Kane, Shubhada; Prabhash, Kumar; Mahimkar, Manoj B

    2016-11-01

    In the present study, we comprehensively analyzed the prevalence of transcriptionally active human papilloma virus (HPV) in tissue samples of Indian patients with leukoplakia, predominantly hyperplastic lesions and head and neck squamous cell carcinoma (HNSCC). In addition, saliva samples from patients with HNSCC were screened for HPV detection. P16 overexpression was analyzed by immunohistochemistry. Tissue samples of leukoplakia (n = 121) and HNSCC (n = 427) and saliva from patients with HNSCC (n = 215) were tested for HPV using nested polymerase chain reaction. Positive samples were sequenced for subtyping. The presence of HPV E6/E7 mRNA was confirmed by RNA in situ hybridization. P16 expression and HPV DNA were not detected in any of the leukoplakia specimens. Of the 427 HNSCC tumors, 9 showed p16 overexpression and 7/427 cases were positive for HPV16 DNA, in saliva or tissue. E6/E7 mRNA positivity was observed in 8 HNSCC samples, primarily from patients with no habit of tobacco consumption. The prevalence of high-risk HPV was restricted to oropharynx and larynx, with very little concordance between p16 overexpression and HPV positivity. All patients with HPV-positive saliva samples had transcriptionally active HPV present in their tumors. The presence of HPV DNA does not necessarily reflect transcriptionally active virus in tumors; hence, it is important to consider this fact while categorizing HPV-associated tumors. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. HSF1 transcriptional activity mediates alcohol induction of Vamp2 expression and GABA release

    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.

  4. The Transcriptional Repressive Activity of KRAB Zinc Finger Proteins Does Not Correlate with Their Ability to Recruit TRIM28.

    Kristin E Murphy

    Full Text Available KRAB domain Zinc finger proteins are one of the most abundant families of transcriptional regulators in higher vertebrates. The prevailing view is that KRAB domain proteins function as potent transcriptional repressors by recruiting TRIM28 and promoting heterochromatin spreading. However, the extent to which all KRAB domain proteins are TRIM28-dependent transcriptional repressors is currently unclear. Our studies on mouse ZFP568 revealed that TRIM28 recruitment by KRAB domain proteins is not sufficient to warrant transcriptional repressive activity. By using luciferase reporter assays and yeast two-hybrid experiments, we tested the ability of ZFP568 and other mouse KRAB domain proteins to repress transcription and bind TRIM28. We found that some mouse KRAB domain proteins are poor transcriptional repressors despite their ability to recruit TRIM28, while others showed strong KRAB-dependent transcriptional repression, but no TRIM28 binding. Together, our results show that the transcriptional repressive activity of KRAB-ZNF proteins does not correlate with their ability to recruit TRIM28, and provide evidence that KRAB domains can regulate transcription in a TRIM28-independent fashion. Our findings challenge the current understanding of the molecular mechanisms used by KRAB domain proteins to control gene expression and highlight that a high percentage of KRAB domain proteins in the mouse genome differ from the consensus KRAB sequence at amino acid residues that are critical for TRIM28 binding and/or repressive activity.

  5. An active role for endogenous beta-1,3-glucanase genes in transgene-mediated co-suppression in tobacco.

    Sanders, Matthew; Maddelein, Wendy; Depicker, Anna; Van Montagu, Marc; Cornelissen, Marc; Jacobs, John

    2002-11-01

    Post-transcriptional gene silencing (PTGS) is characterized by the accumulation of short interfering RNAs that are proposed to mediate sequence-specific degradation of cognate and secondary target mRNAs. In plants, it is unclear to what extent endogenous genes contribute to this process. Here, we address the role of the endogenous target genes in transgene-mediated PTGS of beta-1,3-glucanases in tobacco. We found that mRNA sequences of the endogenous glucanase glb gene with varying degrees of homology to the Nicotiana plumbaginifolia gn1 transgene are targeted by the silencing machinery, although less efficiently than corresponding transgene regions. Importantly, we show that endogene-specific nucleotides in the glb sequence provide specificity to the silencing process. Consistent with this finding, small sense and antisense 21- to 23-nucleotide RNAs homologous to the endogenous glb gene were detected. Combined, these data demonstrate that a co-suppressed endogenous glucan ase gene is involved in signal amplification and selection of homologous targets, and show that endogenous genes can actively participate in PTGS in plants. The findings are introduced as a further sophistication of the post-transciptional silencing model.

  6. Recent behavioral history modifies coupling between cell activity and Arc gene transcription in hippocampal CA1 neurons.

    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.

  7. Active Vibration Suppression of a 3-DOF Flexible Parallel Manipulator Using Efficient Modal Control

    Quan Zhang

    2014-01-01

    Full Text Available This paper addresses the dynamic modeling and efficient modal control of a planar parallel manipulator (PPM with three flexible linkages actuated by linear ultrasonic motors (LUSM. To achieve active vibration control, multiple lead zirconate titanate (PZT transducers are mounted on the flexible links as vibration sensors and actuators. Based on Lagrange’s equations, the dynamic model of the flexible links is derived with the dynamics of PZT actuators incorporated. Using the assumed mode method (AMM, the elastic motion of the flexible links are discretized under the assumptions of pinned-free boundary conditions, and the assumed mode shapes are validated through experimental modal test. Efficient modal control (EMC, in which the feedback forces in different modes are determined according to the vibration amplitude or energy of their own, is employed to control the PZT actuators to realize active vibration suppression. Modal filters are developed to extract the modal displacements and velocities from the vibration sensors. Numerical simulation and vibration control experiments are conducted to verify the proposed dynamic model and controller. The results show that the EMC method has the capability of suppressing multimode vibration simultaneously, and both the structural and residual vibrations of the flexible links are effectively suppressed using EMC approach.

  8. BFV activates the NF-κB pathway through its transactivator (BTas) to enhance viral transcription

    Wang Jian; Tan Juan; Zhang Xihui; Guo Hongyan; Zhang Qicheng; Guo Tingting; Geng Yunqi; Qiao Wentao

    2010-01-01

    Multiple families of viruses have evolved sophisticated strategies to regulate nuclear factor-κB (NF-κB) signaling, which plays a pivotal role in diverse cellular events, including virus-host interactions. In this study, we report that bovine foamy virus (BFV) is able to activate the NF-κB pathway through the action of its transactivator, BTas. Both cellular IKKβ and IκBα also participate in this activation. In addition, we demonstrate that BTas induces the processing of p100, which implies that BTas can activate NF-κB through a noncanonical pathway as well. Co-immunoprecipitation analysis shows that BTas interacts with IKK catalytic subunits (IKKα and IKKβ), which may be responsible for regulation of IKK kinase activity and persistent NF-κB activation. Furthermore, our results indicate that the level of BTas-mediated LTR transcription correlates with the activity of cellular NF-κB. Together, this study suggests that BFV activates the NF-κB pathway through BTas to enhance viral transcription.

  9. Hybrid Active Filter with Variable Conductance for Harmonic Resonance Suppression in Industrial Power Systems

    Lee, Tzung-Lin; Wang, Yen-Ching; Li, Jian-Cheng

    2015-01-01

    Unintentional series and/or parallel resonances, due to the tuned passive filter and the line inductance, may result in severe harmonic distortion in the industrial power system. This paper presents a hybrid active filter to suppress harmonic resonance and reduce harmonic distortion as well...... expensive. A reasonable trade-off between filtering performances and cost is to use the hybrid active filter. Design consideration are presented and experimental results are provided to validate effectiveness of the proposed method. Furthermore, this paper discusses filtering performances on line impedance...

  10. Protein Kinases and Transcription Factors Activation in Response to UV-Radiation of Skin: Implications for Carcinogenesis

    Laurence A. Marchat; Elena Aréchaga Ocampo; Mavil López Casamichana; Carlos Pérez-Plasencia; César López-Camarillo; Elizbeth Álvarez-Sánchez

    2011-01-01

    Solar ultraviolet (UV) radiation is an important environmental factor that leads to immune suppression, inflammation, photoaging, and skin carcinogenesis. Here, we reviewed the specific signal transduction pathways and transcription factors involved in the cellular response to UV-irradiation. Increasing experimental data supporting a role for p38, MAPK, JNK, ERK1/2, and ATM kinases in the response network to UV exposure is discussed. We also reviewed the participation of NF-?B, AP-1, and NRF2...

  11. Study on Active Suppression Control of Drivetrain Oscillations in an Electric Vehicle

    Huang, Lei; Cui, Ying

    2017-07-01

    Due to the low damping in a central driven electric vehicle and lack of passive damping mechanisms as compared with a conventional vehicle, the vehicle may endure torsional vibrations which may deteriorates the vehicle’s drivability. Thus active damping control strategy is required to reduce the undesirable oscillations in an EV. In this paper, the origin of the vibration and the design of a damping control method to suppress such oscillations to improve the drivability of an EV are studied. The traction motor torque that is given by the vehicle controller is adjusted according to the acceleration rate of the motor speed to attenuate the resonant frequency. Simulations and experiments are performed to validate the system. The results show that the proposed control system can effectively suppress oscillations and hence improve drivability.

  12. Compton suppression spectrometry for analysis of short-lived neutron activation products in foods

    Anderson, D.L.; Cunningham, W.C.

    2008-01-01

    Compton suppression spectrometry was used to analyze foods for elements with short-lived neutron activation products (half-lives of about 2 minutes to 1.5 days). Analysis conditions were optimized to provide quality assurance analyses for iodine in FDA's Total Diet Study. Iodine mass fractions (0.075 to 2.03 mg/kg) were measured in 19 of 42 foods analyzed, with limits of detection (LODs) ranging from 0.03 to 1.4 mg/kg, mostly depending on NaCl content. LODs were lowered by up to a factor of 2 for 16 elements. Suppression factors ranged from about 2 to 8 over the energy range 400 to 3200 keV. (author)

  13. Analysis of Harmonics Suppression by Active Damping Control on Multi Slim DC-link Drives

    Yang, Feng; Máthé, Lászlo; Lu, Kaiyuan

    2016-01-01

    Compared with conventional dc-link drive, slim dc-link drive is expected to achieve lower cost and longer life time. However, harmonics distortion problem may occur in such drive systems. This paper proposes to use an active damping control method to suppress the harmonic distortion...... with the benefit of low cost and also low loss. A new analysis method, based on the frequency domain impedance model, is presented to explore the mechanism of harmonics suppression. Also, a general method is presented to build the impedance model of a PMSM drive system using Field Oriented Control (FOC) method....... Some design issues, including power levels, current control bandwidth and harmonic interaction, are discussed when the drive system is fed by a weak grid. Case studies on a two-drive system composed by two slim dc-link drive units are provided to verify the proposed analysis method....

  14. Cell Cycle-Dependent Recruitment of Polycomb Proteins to the ASNS Promoter Counteracts C/ebp-Mediated Transcriptional Activation in Bombyx mori

    Li, Zhiqing; Cheng, Daojun; Mon, Hiroaki; Zhu, Li; Xu, Jian; Tatsuke, Tsuneyuki; Lee, Jae Man; Xia, Qingyou; Kusakabe, Takahiro

    2013-01-01

    Epigenetic modifiers and transcription factors contribute to developmentally programmed gene expression. Here, we establish a functional link between epigenetic regulation by Polycomb group (PcG) proteins and transcriptional regulation by C/ebp that orchestrates the correct expression of Bombyx mori asparagine synthetase (BmASNS), a gene involved in the biosynthesis of asparagine. We show that the cis-regulatory elements of YY1-binding motifs and the CpG island present on the BmASNS promoter are required for the recruitment of PcG proteins and the subsequent deposition of the epigenetic repression mark H3K27me3. RNAi-mediated knockdown of PcG genes leads to derepression of the BmASNS gene via the recruitment of activators, including BmC/ebp, to the promoter. Intriguingly, we find that PcG proteins and BmC/ebp can dynamically modulate the transcriptional output of the BmASNS target in a cell cycle-dependent manner. It will be essential to suppress BmASNS expression by PcG proteins at the G2/M phase of the cell cycle in the presence of BmC/ebp activator. Thus, our results provide a novel insight into the molecular mechanism underlying the recruitment and regulation of the PcG system at a discrete gene locus in Bombyx mori. PMID:23382816

  15. Functional clonal deletion versus active suppression in transplantation tolerance induced by total-lymphoid irradiation

    Morecki, S.; Leshem, B.; Weigensberg, M.; Bar, S.; Slavin, S.

    1985-01-01

    Transplantation tolerance and stable chimerism were established in adult mice conditioned with a short course of total-lymphoid irradiation (TLI) followed by infusion of 30 X 10(6) allogeneic bone marrow cells. Spleen cells of tolerant mice could not exert a proliferative or cytotoxic response against host-type cells in vitro and were unable to induce graft-versus-host reaction in secondary host-type recipients. The degree of suppression assessed by coculturing tolerant splenocytes in vitro in the one-way mixed lymphocyte reaction was quite variable--and, in some cases, was not at all demonstrable, although tolerance was clearly maintained. Suppression, when apparent, could not be ascribed to T lymphocytes. Suppressor cells were found to bind soybean agglutinin and could be separated from the nonsuppressive cells by means of this lectin. Dissociation of the suppressive population (SBA+ cells) from that which is normally alloreactive (SBA- cells) resulted in a suppressor cell-depleted fraction that was still unable to respond to host-type cells but regained reactivity to unrelated cells. Limiting dilution analysis of chimeric splenocytes revealed markedly reduced frequencies of cytotoxic T lymphocyte precursors (CTL-P) directed against host-type cells, as compared with normal splenocytes reacting against the same target cells. This difference was accentuated when these cells were sensitized to host-type target cells prior to plating in limiting dilution cultures. In 1:1 mixing experiments of normal and chimeric splenocytes, there was no evidence of any in vitro suppressive activity to account for hyporeactivity of chimeric cells against host-type cells. Thus, maintenance of TLI-induced tolerance seemed not to be mediated primarily through an active suppressor cell mechanism

  16. Transcriptional Regulation During Zygotic Genome Activation in Zebrafish and Other Anamniote Embryos.

    Wragg, J; Müller, F

    2016-01-01

    Embryo development commences with the fusion of two terminally differentiated haploid gametes into the totipotent fertilized egg, which through a series of major cellular and molecular transitions generate a pluripotent cell mass. The activation of the zygotic genome occurs during the so-called maternal to zygotic transition and prepares the embryo for zygotic takeover from maternal factors, in the control of the development of cellular lineages during differentiation. Recent advances in next generation sequencing technologies have allowed the dissection of the genomic and epigenomic processes mediating this transition. These processes include reorganization of the chromatin structure to a transcriptionally permissive state, changes in composition and function of structural and regulatory DNA-binding proteins, and changeover of the transcriptome as it is overhauled from that deposited by the mother in the oocyte to a zygotically transcribed complement. Zygotic genome activation in zebrafish occurs 10 cell cycles after fertilization and provides an ideal experimental platform for elucidating the temporal sequence and dynamics of establishment of a transcriptionally active chromatin state and helps in identifying the determinants of transcription activation at polymerase II transcribed gene promoters. The relatively large number of pluripotent cells generated by the fast cell divisions before zygotic transcription provides sufficient biomass for next generation sequencing technology approaches to establish the temporal dynamics of events and suggest causative relationship between them. However, genomic and genetic technologies need to be improved further to capture the earliest events in development, where cell number is a limiting factor. These technologies need to be complemented with precise, inducible genetic interference studies using the latest genome editing tools to reveal the function of candidate determinants and to confirm the predictions made by classic

  17. CITED2 modulates estrogen receptor transcriptional activity in breast cancer cells

    Lau, Wen Min; Doucet, Michele; Huang, David; Weber, Kristy L.; Kominsky, Scott L.

    2013-01-01

    Highlights: •The effects of elevated CITED2 on ER function in breast cancer cells are examined. •CITED2 enhances cell growth in the absence of estrogen and presence of tamoxifen. •CITED2 functions as a transcriptional co-activator of ER in breast cancer cells. -- Abstract: Cbp/p300-interacting transactivator with Glu/Asp-rich carboxy-terminal domain 2 (CITED2) is a member of the CITED family of non-DNA binding transcriptional co-activators of the p300/CBP-mediated transcription complex. Previously, we identified CITED2 as being overexpressed in human breast tumors relative to normal mammary epithelium. Upon further investigation within the estrogen receptor (ER)-positive subset of these breast tumor samples, we found that CITED2 mRNA expression was elevated in those associated with poor survival. In light of this observation, we investigated the effect of elevated CITED2 levels on ER function. While ectopic overexpression of CITED2 in three ER-positive breast cancer cell lines (MCF-7, T47D, and CAMA-1) did not alter cell proliferation in complete media, growth was markedly enhanced in the absence of exogenous estrogen. Correspondingly, cells overexpressing CITED2 demonstrated reduced sensitivity to the growth inhibitory effects of the selective estrogen receptor modulator, 4-hydroxytamoxifen. Subsequent studies revealed that basal ER transcriptional activity was elevated in CITED2-overexpressing cells and was further increased upon the addition of estrogen. Similarly, basal and estrogen-induced expression of the ER-regulated genes trefoil factor 1 (TFF1) and progesterone receptor (PGR) was higher in cells overexpressing CITED2. Concordant with this observation, ChIP analysis revealed higher basal levels of CITED2 localized to the TFF-1 and PGR promoters in cells with ectopic overexpression of CITED2, and these levels were elevated further in response to estrogen stimulation. Taken together, these data indicate that CITED2 functions as a transcriptional co-activator

  18. Histone H4 Lys 20 methyltransferase SET8 promotes androgen receptor-mediated transcription activation in prostate cancer

    Yao, Lushuai [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Yanyan; Du, Fengxia [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); Han, Xiao [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohua [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China); Niu, Yuanjie [Chawnshang Chang Sex Hormone Research Center, Tianjin Institute of Urology, Tianjin Medical University, Tianjin 300070 (China); Ren, Shancheng, E-mail: renshancheng@gmail.com [Department of Urology, Shanghai Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); Sun, Yingli, E-mail: sunyl@big.ac.cn [Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101 (China)

    2014-07-18

    Highlights: • Dihydrotestosterone stimulates H4K20me1 enrichment at the PSA promoter. • SET8 promotes AR-mediated transcription activation. • SET8 interacts with AR and promotes cell proliferation. - Abstract: Histone methylation status in different lysine residues has an important role in transcription regulation. The effect of H4K20 monomethylation (H4K20me1) on androgen receptor (AR)-mediated gene transcription remains unclear. Here we show that AR agonist stimulates the enrichment of H4K20me1 and SET8 at the promoter of AR target gene PSA in an AR dependent manner. Furthermore, SET8 is crucial for the transcription activation of PSA. Co-immunoprecipitation analyses demonstrate that SET8 interacts with AR. Therefore, we conclude that SET8 is involved in AR-mediated transcription activation, possibly through its interaction with AR and H4K20me1 modification.

  19. Chimaerin suppresses Rac1 activation at the apical membrane to maintain the cyst structure.

    Shunsuke Yagi

    Full Text Available Epithelial organs are made of a well-polarized monolayer of epithelial cells, and their morphology is maintained strictly for their proper functions. Previously, we showed that Rac1 activation is suppressed at the apical membrane in the mature organoid, and that such spatially biased Rac1 activity is required for the polarity maintenance. Here we identify Chimaerin, a GTPase activating protein for Rac1, as a suppressor of Rac1 activity at the apical membrane. Depletion of Chimaerin causes over-activation of Rac1 at the apical membrane in the presence of hepatocyte growth factor (HGF, followed by luminal cell accumulation. Importantly, Chimaerin depletion did not inhibit extension formation at the basal membrane. These observations suggest that Chimaerin functions as the apical-specific Rac1 GAP to maintain epithelial morphology.

  20. BTG2 is an LXXLL-dependent co-repressor for androgen receptor transcriptional activity

    Hu, Xu-Dong; Meng, Qing-Hui; Xu, Jia-Ying; Jiao, Yang; Ge, Chun-Min; Jacob, Asha; Wang, Ping; Rosen, Eliot M; Fan, Saijun

    2011-01-01

    Research highlights: → BTG2 associates with AR, androgen causes an increase of the interaction. → BTG2 as a co-repressor inhibits the AR-mediated transcription activity. → BTG2 inhibits the transcription activity and expression of PSA. → An intact 92 LxxLL 96 motif is essential and necessary for these activities of BTG2, while the 20 LxxLL 24 motif is not required. → Ectopic expression of BTG2 reduces proliferation of prostate cancer cells. -- Abstract: The tumor suppressor gene, BTG2 has been down-regulated in prostate cancer and the ectopic expression of this gene has been shown to inhibit prostate cancer cell growth. Sequence analysis revealed that the BTG2 protein contains two leucine-rich motifs ( 20 LxxLL 24 and 92 LxxLL 96 ), which are usually found in nuclear receptor co-factors. Based on this, we postulated that there will be an association between BTG2 and AR. In this study, we discovered that BTG2 directly bound to the androgen receptor (AR) in the absence of 5α-dihydrotestosterone (DHT), and in the presence of the androgen, this interaction was increased. BTG2 bearing the mutant 20 LxxLL 24 motif bound to AR equally efficient as the wild-type BTG2, while BTG2 bearing the mutant 92 LxxLL 96 motif failed to interact with AR. Functional studies indicated that ectopic expression of BTG2 caused a significant inhibition of AR-mediated transcriptional activity and a decreased growth of prostate cancer cells. Androgen-induced promoter activation and expression of prostate-specific antigen (PSA) are significantly attenuated by BTG2. The intact 92 LxxLL 96 motif is required for these activities. These findings, for the first time, demonstrate that BTG2 complexes with AR via an LxxLL-dependent mechanism and may play a role in prostate cancer via modulating the AR signaling pathway.

  1. Transcriptional co-activator PGC-1 alpha drives the formation of slow-twitch muscle fibres.

    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.

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

    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

  3. The role of RNA polymerase I transcription and embryonic genome activation in nucleolar development in bovine preimplantation embryos

    Østrup, Olga; Strejcek, F.; Petrovicova, I.

    2008-01-01

    The aim of the present study was to investigate the role of RNA polymerase I (RPI) transcription in nucleolar development during major transcriptional activation (MTA) in cattle. Late eight-cell embryos were cultured in the absence (control group) or presence of actinomycin D (AD) (RPI inhibition...

  4. Cooperative activation of cardiac transcription through myocardin bridging of paired MEF2 sites

    Anderson, Courtney M. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Hu, Jianxin [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Thomas, Reuben [Univ. of California, San Francisco, CA (United States). Gladstone Inst.; Gainous, T. Blair [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Celona, Barbara [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Sinha, Tanvi [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Dickel, Diane E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Genomics Division; Heidt, Analeah B. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Xu, Shan-Mei [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Bruneau, Benoit G. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Univ. of California, San Francisco, CA (United States). Gladstone Inst.; Pollard, Katherine S. [Univ. of California, San Francisco, CA (United States). Gladstone Inst.; Pennacchio, Len A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Genomics Division; Black, Brian L. [Univ. of California, San Francisco, CA (United States). Cardiovascular Research Inst.; Univ. of California, San Francisco, CA (United States). Dept. of

    2017-03-28

    Enhancers frequently contain multiple binding sites for the same transcription factor. These homotypic binding sites often exhibit synergy, whereby the transcriptional output from two or more binding sites is greater than the sum of the contributions of the individual binding sites alone. Although this phenomenon is frequently observed, the mechanistic basis for homotypic binding site synergy is poorly understood. Here in this paper, we identify a bona fide cardiac-specific Prkaa2 enhancer that is synergistically activated by homotypic MEF2 binding sites. We show that two MEF2 sites in the enhancer function cooperatively due to bridging of the MEF2C-bound sites by the SAP domain-containing co-activator protein myocardin, and we show that paired sites buffer the enhancer from integration site-dependent effects on transcription in vivo. Paired MEF2 sites are prevalent in cardiac enhancers, suggesting that this might be a common mechanism underlying synergy in the control of cardiac gene expression in vivo.

  5. Cyclin D3 interacts with vitamin D receptor and regulates its transcription activity

    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

  6. Transcriptional activation of melanocortin 2 receptor accessory protein by PPARγ in adipocytes

    Kim, Nam Soo; Kim, Yoon-Jin [Department of Biology, Research Institute for Basic Science, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Cho, Si Young [R and D Center, Amore Pacific Corporation, Yongin-si, Gyeonggi-do 446-729 (Korea, Republic of); Lee, Tae Ryong, E-mail: trlee@amorepacific.com [R and D Center, Amore Pacific Corporation, Yongin-si, Gyeonggi-do 446-729 (Korea, Republic of); Kim, Sang Hoon, E-mail: shkim@khu.ac.kr [Department of Biology, Research Institute for Basic Science, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

    2013-09-27

    Highlights: •MRAP enhanced HSL expression. •ACTH-mediated MRAP reduced glycerol release. •PPARγ induced MRAP expression. •PPARγ bound to the MRAP promoter. -- Abstract: Adrenocorticotropic hormone (ACTH) in rodents decreases lipid accumulation and body weight. Melanocortin receptor 2 (MC2R) and MC2R accessory protein (MRAP) are specific receptors for ACTH in adipocytes. Peroxisome proliferator-activated receptor γ (PPARγ) plays a role in the transcriptional regulation of metabolic pathways such as adipogenesis and β-oxidation of fatty acids. In this study we investigated the transcriptional regulation of MRAP expression during differentiation of 3T3-L1 cells. Stimulation with ACTH affected lipolysis in murine mature adipocytes via MRAP. Putative peroxisome proliferator response element (PPRE) was identified in the MRAP promoter region. In chromatin immunoprecipitation and reporter assays, we observed binding of PPARγ to the MRAP promoter. The mutagenesis experiments showed that the −1209/−1198 region of the MRAP promoter could function as a PPRE site. These results suggest that PPARγ is required for transcriptional activation of the MRAP gene during adipogenesis, which contributes to understanding of the molecular mechanism of lipolysis in adipocytes.

  7. A Transcription Activator-Like Effector (TALE) Toolbox for Genome Engineering

    Sanjana, Neville E.; Cong, Le; Zhou, Yang; Cunniff, Margaret M.; Feng, Guoping; Zhang, Feng

    2013-01-01

    Transcription activator-like effectors (TALEs) are a class of naturally occurring DNA binding proteins found in the plant pathogen Xanthomonas sp. The DNA binding domain of each TALE consists of tandem 34-amino acid repeat modules that can be rearranged according to a simple cipher to target new DNA sequences. Customized TALEs can be used for a wide variety of genome engineering applications, including transcriptional modulation and genome editing. Here we describe a toolbox for rapid construction of custom TALE transcription factors (TALE-TFs) and nucleases (TALENs) using a hierarchical ligation procedure. This toolbox facilitates affordable and rapid construction of custom TALE-TFs and TALENs within one week and can be easily scaled up to construct TALEs for multiple targets in parallel. We also provide details for testing the activity in mammalian cells of custom TALE-TFs and TALENs using, respectively, qRT-PCR and Surveyor nuclease. The TALE toolbox described here will enable a broad range of biological applications. PMID:22222791

  8. Transcriptional activation of melanocortin 2 receptor accessory protein by PPARγ in adipocytes

    Kim, Nam Soo; Kim, Yoon-Jin; Cho, Si Young; Lee, Tae Ryong; Kim, Sang Hoon

    2013-01-01

    Highlights: •MRAP enhanced HSL expression. •ACTH-mediated MRAP reduced glycerol release. •PPARγ induced MRAP expression. •PPARγ bound to the MRAP promoter. -- Abstract: Adrenocorticotropic hormone (ACTH) in rodents decreases lipid accumulation and body weight. Melanocortin receptor 2 (MC2R) and MC2R accessory protein (MRAP) are specific receptors for ACTH in adipocytes. Peroxisome proliferator-activated receptor γ (PPARγ) plays a role in the transcriptional regulation of metabolic pathways such as adipogenesis and β-oxidation of fatty acids. In this study we investigated the transcriptional regulation of MRAP expression during differentiation of 3T3-L1 cells. Stimulation with ACTH affected lipolysis in murine mature adipocytes via MRAP. Putative peroxisome proliferator response element (PPRE) was identified in the MRAP promoter region. In chromatin immunoprecipitation and reporter assays, we observed binding of PPARγ to the MRAP promoter. The mutagenesis experiments showed that the −1209/−1198 region of the MRAP promoter could function as a PPRE site. These results suggest that PPARγ is required for transcriptional activation of the MRAP gene during adipogenesis, which contributes to understanding of the molecular mechanism of lipolysis in adipocytes

  9. Adenovirus type 5 E1A and E6 proteins of low-risk cutaneous beta-human papillomaviruses suppress cell transformation through interaction with FOXK1/K2 transcription factors.

    Komorek, Jessica; Kuppuswamy, Mohan; Subramanian, T; Vijayalingam, S; Lomonosova, Elena; Zhao, Ling-Jun; Mymryk, Joe S; Schmitt, Kimberly; Chinnadurai, G

    2010-03-01

    The adenovirus (Adv) oncoprotein E1A stimulates cell proliferation and inhibits differentiation. These activities are primarily linked to the N-terminal region (exon 1) of E1A, which interacts with multiple cellular protein complexes. The C terminus (exon 2) of E1A antagonizes these processes, mediated in part through interaction with C-terminal binding proteins 1 and 2 (CtBP1/2). To identify additional cellular E1A targets that are involved in the modulation of E1A C-terminus-mediated activities, we undertook tandem affinity purification of E1A-associated proteins. Through mass spectrometric analysis, we identified several known E1A-interacting proteins as well as novel E1A targets, such as the forkhead transcription factors, FOXK1/K2. We identified a Ser/Thr-containing sequence motif in E1A that mediated interaction with FOXK1/K2. We demonstrated that the E6 proteins of two beta-human papillomaviruses (HPV14 and HPV21) associated with epidermodysplasia verruciformis also interacted with FOXK1/K2 through a motif similar to that of E1A. The E1A mutants deficient in interaction with FOXK1/K2 induced enhanced cell proliferation and oncogenic transformation. The hypertransforming activity of the mutant E1A was suppressed by HPV21 E6. An E1A-E6 chimeric protein containing the Ser/Thr domain of the E6 protein in E1A interacted efficiently with FOXK1/K2 and inhibited cell transformation. Our results suggest that targeting FOXK1/K2 may be a common mechanism for certain beta-HPVs and Adv5. E1A exon 2 mutants deficient in interaction with the dual-specificity kinases DYRK1A/1B and their cofactor HAN11 also induced increased cell proliferation and transformation. Our results suggest that the E1A C-terminal region may suppress cell proliferation and oncogenic transformation through interaction with three different cellular protein complexes: FOXK1/K2, DYRK(1A/1B)/HAN11, and CtBP1/2.

  10. Peroxisome Proliferator-Activated Receptor-γ Inhibits Transformed Growth of Non-Small Cell Lung Cancer Cells through Selective Suppression of Snail

    Rashmi Choudhary

    2010-03-01

    Full Text Available Work from our laboratory and others has demonstrated that activation of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ inhibits transformed growth of non-small cell lung cancer (NSCLC cell lines in vitro and in vivo. We have demonstrated that activation of PPARγ promotes epithelial differentiation of NSCLC by increasing expression of E-cadherin, as well as inhibiting expression of COX-2 and nuclear factor-κB. The Snail family of transcription factors, which includes Snail (Snail1, Slug (Snail2, and ZEB1, is an important regulator of epithelial-mesenchymal transition, as well as cell survival. The goal of this study was to determine whether the biological responses to rosiglitazone, a member of the thiazolidinedione family of PPARγ activators, are mediated through the regulation of Snail family members. Our results indicate that, in two independent NSCLC cell lines, rosiglitazone specifically decreased expression of Snail, with no significant effect on either Slug or ZEB1. Suppression of Snail using short hairpin RNA silencing mimicked the effects of PPARγ activation, in inhibiting anchorage-independent growth, promoting acinar formation in three-dimensional culture, and inhibiting invasiveness. This was associated with the increased expression of E-cadherin and decreased expression of COX-2 and matrix metaloproteinases. Conversely, overexpression of Snail blocked the biological responses to rosiglitazone, increasing anchorage-independent growth, invasiveness, and promoting epithelial-mesenchymal transition. The suppression of Snail expression by rosiglitazone seemed to be independent of GSK-3 signaling but was rather mediated through suppression of extracellular signal-regulated kinase activity. These findings suggest that selective regulation of Snail may be critical in mediating the antitumorigenic effects of PPARγ activators.

  11. Activating RNAs associate with Mediator to enhance chromatin architecture and transcription

    Lai, Fan; Orom, Ulf A; Cesaroni, Matteo; Beringer, Malte; Taatjes, Dylan J; Blobel, Gerd A.; Shiekhattar, Ramin

    2013-01-01

    Recent advances in genomic research have revealed the existence of a large number of transcripts devoid of protein-coding potential in multiple organisms 1-8 . While the functional role for long non-coding RNAs (lncRNAs) has been best defined in epigenetic phenomena such as X inactivation and imprinting, different classes of lncRNAs may have varied biological functions 8-13 . We and others have identified a class of lncRNAs, termed ncRNA-activating (ncRNA-a), that function to activate their n...

  12. Fucose-Mediated Transcriptional Activation of the fcs Operon by FcsR in Streptococcus pneumoniae.

    Manzoor, Irfan; Shafeeq, Sulman; Afzal, Muhammad; Kuipers, Oscar P

    2015-01-01

    In this study, we explore the impact of fucose on the transcriptome of S. pneumoniae D39. The expression of various genes and operons, including the fucose uptake PTS and utilization operon (fcs operon) was altered in the presence of fucose. By means of quantitative RT-PCR and β-galactosidase analysis, we demonstrate the role of the transcriptional regulator FcsR, present upstream of the fcs operon, as a transcriptional activator of the fcs operon. We also predict a 19-bp putative FcsR regulatory site (5'-ATTTGAACATTATTCAAGT-3') in the promoter region of the fcs operon. The functionality of this predicted FcsR regulatory site was further confirmed by promoter-truncation experiments, where deletion of half of the FscR regulatory site or full deletion led to the abolition of expression of the fcs operon. © 2015 S. Karger AG, Basel.

  13. Molecular genetic analysis of activation-tagged transcription factors thought to be involved in photomorphogenesis

    Neff, Michael M.

    2011-06-23

    This is a final report for Department of Energy Grant No. DE-FG02-08ER15927 entitled “Molecular Genetic Analysis of Activation-Tagged Transcription Factors Thought to be Involved in Photomorphogenesis”. Based on our preliminary photobiological and genetic analysis of the sob1-D mutant, we hypothesized that OBP3 is a transcription factor involved in both phytochrome and cryptochrome-mediated signal transduction. In addition, we hypothesized that OBP3 is involved in auxin signaling and root development. Based on our preliminary photobiological and genetic analysis of the sob2-D mutant, we also hypothesized that a related gene, LEP, is involved in hormone signaling and seedling development.

  14. TAF4 nucleates a core subcomplex of TFIID and mediates activated transcription from a TATA-less promoter

    Wright, Kevin J.; Marr, Michael T.; Tjian, Robert

    2006-01-01

    Activator-dependent recruitment of TFIID initiates formation of the transcriptional preinitiation complex. TFIID binds core promoter DNA elements and directs the assembly of other general transcription factors, leading to binding of RNA polymerase II and activation of RNA synthesis. How TATA box-binding protein (TBP) and the TBP-associated factors (TAFs) are assembled into a functional TFIID complex with promoter recognition and coactivator activities in vivo remains unknown. Here, we use RNA...

  15. The Transcriptional Signature of Active Tuberculosis Reflects Symptom Status in Extra-Pulmonary and Pulmonary Tuberculosis.

    Simon Blankley

    Full Text Available Mycobacterium tuberculosis infection is a leading cause of infectious death worldwide. Gene-expression microarray studies profiling the blood transcriptional response of tuberculosis (TB patients have been undertaken in order to better understand the host immune response as well as to identify potential biomarkers of disease. To date most of these studies have focused on pulmonary TB patients with gene-expression profiles of extra-pulmonary TB patients yet to be compared to those of patients with pulmonary TB or sarcoidosis.A novel cohort of patients with extra-pulmonary TB and sarcoidosis was recruited and the transcriptional response of these patients compared to those with pulmonary TB using a variety of transcriptomic approaches including testing a previously defined 380 gene meta-signature of active TB.The 380 meta-signature broadly differentiated active TB from healthy controls in this new dataset consisting of pulmonary and extra-pulmonary TB. The top 15 genes from this meta-signature had a lower sensitivity for differentiating extra-pulmonary TB from healthy controls as compared to pulmonary TB. We found the blood transcriptional responses in pulmonary and extra-pulmonary TB to be heterogeneous and to reflect the extent of symptoms of disease.The transcriptional signature in extra-pulmonary TB demonstrated heterogeneity of gene expression reflective of symptom status, while the signature of pulmonary TB was distinct, based on a higher proportion of symptomatic individuals. These findings are of importance for the rational design and implementation of mRNA based TB diagnostics.

  16. Activity-Based Anorexia Alters the Expression of BDNF Transcripts in the Mesocorticolimbic Reward Circuit.

    Ho, Emily V; Klenotich, Stephanie J; McMurray, Matthew S; Dulawa, Stephanie C

    2016-01-01

    Anorexia nervosa (AN) is a complex eating disorder with severe dysregulation of appetitive behavior. The activity-based anorexia (ABA) paradigm is an animal model in which rodents exposed to both running wheels and scheduled feeding develop aspects of AN including paradoxical hypophagia, dramatic weight loss, and hyperactivity, while animals exposed to only one condition maintain normal body weight. Brain-derived neurotrophic factor (BDNF), an activity-dependent modulator of neuronal plasticity, is reduced in the serum of AN patients, and is a known regulator of feeding and weight maintenance. We assessed the effects of scheduled feeding, running wheel access, or both on the expression of BDNF transcripts within the mesocorticolimbic pathway. We also assessed the expression of neuronal cell adhesion molecule 1 (NCAM1) to explore the specificity of effects on BDNF within the mesocorticolimbic pathway. Scheduled feeding increased the levels of both transcripts in the hippocampus (HPC), increased NCAM1 mRNA expression in the ventral tegmental area (VTA), and decreased BDNF mRNA levels in the medial prefrontal cortex (mPFC). In addition, wheel running increased BDNF mRNA expression in the VTA. No changes in either transcript were observed in the nucleus accumbens (NAc). Furthermore, no changes in either transcript were induced by the combined scheduled feeding and wheel access condition. These data indicate that scheduled feeding or wheel running alter BDNF and NCAM1 expression levels in specific regions of the mesocorticolimbic pathway. These findings contribute to our current knowledge of the molecular alterations induced by ABA and may help elucidate possible mechanisms of AN pathology.

  17. A transcriptional coregulator, SPIN·DOC, attenuates the coactivator activity of Spindlin1.

    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.

  18. Role of Active Listening and Listening Effort on Contralateral Suppression of Transient Evoked Otoacousic Emissions.

    Kalaiah, Mohan Kumar; Theruvan, Nikhitha B; Kumar, Kaushlendra; Bhat, Jayashree S

    2017-04-01

    The present study aimed to investigate the effect of active listening and listening effort on the contralateral suppression of transient evoked otoacoustic emissions (CSTEOAEs). Twenty eight young adults participated in the study. Transient evoked otoacoustic emissions (TEOAEs) were recorded using 'linear' clicks at 60 dB peSPL, in three contralateral noise conditions. In condition 1, TEOAEs were obtained in the presence of white noise in the contralateral ear. While, in condition 2, speech was embedded into white noise at +3, -3, and -9 dB signal-to-noise ratio (SNR) and delivered to the contralateral ear. The SNR was varied to investigate the effect of listening effort on the CSTEOAE. In condition 3, speech was played backwards and embedded into white noise at -3 dB SNR. The conditions 1 and 3 served as passive listening condition and the condition 2 served as active listening condition. In active listening condition, the participants categorized the words in to two groups (e.g., animal and vehicle). CSTEOAE was found to be largest in the presence of white noise, and the amount of CSTEOAE was not significantly different between active and passive listening conditions (condition 2 and 3). Listening effort had an effect on the CSTEOAE, the amount of suppression increased with listening effort, when SNR was decreased from +3 dB to -3 dB. However, when the SNR was further reduced to -9 dB, there was no further increase in the amount of CSTEOAE, instead there was a reduction in the amount of suppression. The findings of the present study show that listening effort might affect CSTEOAE.

  19. Promoter polymorphisms in genes involved in porcine myogenesis influence their transcriptional activity.

    Bongiorni, Silvia; Tilesi, Francesca; Bicorgna, Silvia; Iacoponi, Francesca; Willems, Daniela; Gargani, Maria; D'Andrea, MariaSilvia; Pilla, Fabio; Valentini, Alessio

    2014-11-07

    Success of meat production and selection for improvement of meat quality is among the primary aims in animal production. Meat quality traits are economically important in swine; however, the underlying genetic nature is very complex. Therefore, an improved pork production strongly depends on identifying and studying how genetic variations contribute to modulate gene expression. Promoters are key regions in gene modulation as they harbour several binding motifs to transcription regulatory factors. Therefore, polymorphisms in these regions are likely to deeply affect RNA levels and consequently protein synthesis. In this study, we report the identification of single nucleotide polymorphisms (SNPs) in promoter regions of candidate genes involved in development, cellular differentiation and muscle growth in Sus scrofa. We identified SNPs in the promoter regions of genes belonging to the Myogenic Regulatory Factors (MRF) gene family (the Myogenic Differentiation gene, MYOD1) and to Growth and Differentiation Factors (GDF) gene family (Myostatin gene, MSTN, GDF8), in Casertana and Large White breeds. The purpose of this study was to investigate if polymorphisms in the promoters could affect the transcriptional activity of these genes. With this aim, we evaluated in vitro the functional activity of the luciferase reporter gene luc2 activity, driven by two constructs carrying different promoter haplotypes. We tested the effects of the G302A (U12574) transition on the promoter efficiency in MYOD1 gene. We ascertained a difference in transcription efficiency for the two variants. A stronger activity of the A-carrying construct is more evident in C2C12. The luciferase expression driven by the MYOD1-A allelic variant displayed a 3.8-fold increased transcriptional activity. We investigated the activity of two haplotype variants (AY527152) in the promoter of GDF8 gene. The haploptype-1 (A435-A447-A879) up-regulated the expression of the reporter gene by a two-fold increase, and

  20. Mammalian transcriptional hotspots are enriched for tissue specific enhancers near cell type specific highly expressed genes and are predicted to act as transcriptional activator hubs.

    Joshi, Anagha

    2014-12-30

    Transcriptional hotspots are defined as genomic regions bound by multiple factors. They have been identified recently as cell type specific enhancers regulating developmentally essential genes in many species such as worm, fly and humans. The in-depth analysis of hotspots across multiple cell types in same species still remains to be explored and can bring new biological insights. We therefore collected 108 transcription-related factor (TF) ChIP sequencing data sets in ten murine cell types and classified the peaks in each cell type in three groups according to binding occupancy as singletons (low-occupancy), combinatorials (mid-occupancy) and hotspots (high-occupancy). The peaks in the three groups clustered largely according to the occupancy, suggesting priming of genomic loci for mid occupancy irrespective of cell type. We then characterized hotspots for diverse structural functional properties. The genes neighbouring hotspots had a small overlap with hotspot genes in other cell types and were highly enriched for cell type specific function. Hotspots were enriched for sequence motifs of key TFs in that cell type and more than 90% of hotspots were occupied by pioneering factors. Though we did not find any sequence signature in the three groups, the H3K4me1 binding profile had bimodal peaks at hotspots, distinguishing hotspots from mono-modal H3K4me1 singletons. In ES cells, differentially expressed genes after perturbation of activators were enriched for hotspot genes suggesting hotspots primarily act as transcriptional activator hubs. Finally, we proposed that ES hotspots might be under control of SetDB1 and not DNMT for silencing. Transcriptional hotspots are enriched for tissue specific enhancers near cell type specific highly expressed genes. In ES cells, they are predicted to act as transcriptional activator hubs and might be under SetDB1 control for silencing.

  1. Active coping with stress suppresses glucose metabolism in the rat hypothalamus.

    Ono, Yumie; Lin, Hsiao-Chun; Tzen, Kai-Yuan; Chen, Hui-Hsing; Yang, Pai-Feng; Lai, Wen-Sung; Chen, Jyh-Horng; Onozuka, Minoru; Yen, Chen-Tung

    2012-03-01

    We used 18F-fluorodeoxyglucose small-animal positron-emission tomography to determine whether different styles of coping with stress are associated with different patterns of neuronal activity in the hypothalamus. Adult rats were subjected to immobilization (IMO)-stress or to a non-immobilized condition for 30 min, in random order on separate days, each of which was followed by brain-scanning. Some rats in the immobilized condition were allowed to actively cope with the stress by chewing a wooden stick during IMO, while the other immobilized rats were given nothing to chew on. Voxel-based statistical analysis of the brain imaging data shows that chewing counteracted the stress-induced increased glucose uptake in the hypothalamus to the level of the non-immobilized condition. Region-of-interest analysis of the glucose uptake values further showed that chewing significantly suppressed stress-induced increased glucose uptake in the paraventricular hypothalamic nucleus and the anterior hypothalamic area but not in the lateral hypothalamus. Together with the finding that the mean plasma corticosterone concentration at the termination of the IMO was also significantly suppressed when rats had an opportunity to chew a wooden stick, our results showed that active coping by chewing inhibited the activation of the hypothalamic-pituitary-adrenal axis to reduce the endocrine stress response.

  2. Macrophage activation induced by Brucella DNA suppresses bacterial intracellular replication via enhancing NO production.

    Liu, Ning; Wang, Lin; Sun, Changjiang; Yang, Li; Tang, Bin; Sun, Wanchun; Peng, Qisheng

    2015-12-01

    Brucella DNA can be sensed by TLR9 on endosomal membrane and by cytosolic AIM2-inflammasome to induce proinflammatory cytokine production that contributes to partially activate innate immunity. Additionally, Brucella DNA has been identified to be able to act as a major bacterial component to induce type I IFN. However, the role of Brucella DNA in Brucella intracellular growth remains unknown. Here, we showed that stimulation with Brucella DNA promote macrophage activation in TLR9-dependent manner. Activated macrophages can suppresses wild type Brucella intracellular replication at early stage of infection via enhancing NO production. We also reported that activated macrophage promotes bactericidal function of macrophages infected with VirB-deficient Brucella at the early or late stage of infection. This study uncovers a novel function of Brucella DNA, which can help us further elucidate the mechanism of Brucella intracellular survival. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Dipeptidyl Peptidase-4 Inhibitor Anagliptin Prevents Intracranial Aneurysm Growth by Suppressing Macrophage Infiltration and Activation.

    Ikedo, Taichi; Minami, Manabu; Kataoka, Hiroharu; Hayashi, Kosuke; Nagata, Manabu; Fujikawa, Risako; Higuchi, Sei; Yasui, Mika; Aoki, Tomohiro; Fukuda, Miyuki; Yokode, Masayuki; Miyamoto, Susumu

    2017-06-19

    Chronic inflammation plays a key role in the pathogenesis of intracranial aneurysms (IAs). DPP-4 (dipeptidyl peptidase-4) inhibitors have anti-inflammatory effects, including suppressing macrophage infiltration, in various inflammatory models. We examined whether a DPP-4 inhibitor, anagliptin, could suppress the growth of IAs in a rodent aneurysm model. IAs were surgically induced in 7-week-old male Sprague Dawley rats, followed by oral administration of 300 mg/kg anagliptin. We measured the morphologic parameters of aneurysms over time and their local inflammatory responses. To investigate the molecular mechanisms, we used lipopolysaccharide-treated RAW264.7 macrophages. In the anagliptin-treated group, aneurysms were significantly smaller 2 to 4 weeks after IA induction. Anagliptin inhibited the accumulation of macrophages in IAs, reduced the expression of MCP-1 (monocyte chemotactic protein 1), and suppressed the phosphorylation of p65. In lipopolysaccharide-stimulated RAW264.7 cells, anagliptin treatment significantly reduced the production of tumor necrosis factor α, MCP-1, and IL-6 (interleukin 6) independent of GLP-1 (glucagon-like peptide 1), the key mediator in the antidiabetic effects of DPP-4 inhibitors. Notably, anagliptin activated ERK5 (extracellular signal-regulated kinase 5), which mediates the anti-inflammatory effects of statins, in RAW264.7 macrophages. Preadministration with an ERK5 inhibitor blocked the inhibitory effect of anagliptin on MCP-1 and IL-6 expression. Accordingly, the ERK5 inhibitor also counteracted the suppression of p65 phosphorylation in vitro. A DPP-4 inhibitor, anagliptin, prevents the growth of IAs via its anti-inflammatory effects on macrophages. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  4. Dissection of TALE-dependent gene activation reveals that they induce transcription cooperatively and in both orientations.

    Streubel, Jana; Baum, Heidi; Grau, Jan; Stuttman, Johannes; Boch, Jens

    2017-01-01

    Plant-pathogenic Xanthomonas bacteria inject transcription activator-like effector proteins (TALEs) into host cells to specifically induce transcription of plant genes and enhance susceptibility. Although the DNA-binding mode is well-understood it is still ambiguous how TALEs initiate transcription and whether additional promoter elements are needed to support this. To systematically dissect prerequisites for transcriptional initiation the activity of one TALE was compared on different synthetic Bs4 promoter fragments. In addition, a large collection of artificial TALEs spanning the OsSWEET14 promoter was compared. We show that the presence of a TALE alone is not sufficient to initiate transcription suggesting the requirement of additional supporting promoter elements. At the OsSWEET14 promoter TALEs can initiate transcription from various positions, in a synergistic manner of multiple TALEs binding in parallel to the promoter, and even by binding in reverse orientation. TALEs are known to shift the transcriptional start site, but our data show that this shift depends on the individual position of a TALE within a promoter context. Our results implicate that TALEs function like classical enhancer-binding proteins and initiate transcription in both orientations which has consequences for in planta target gene prediction and design of artificial activators.

  5. In Vitro Anticancer Activity of Phlorofucofuroeckol A via Upregulation of Activating Transcription Factor 3 against Human Colorectal Cancer Cells

    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.

  6. Opiate-induced suppression of rat hypoglossal motoneuron activity and its reversal by ampakine therapy.

    Amanda R Lorier

    2010-01-01

    Full Text Available Hypoglossal (XII motoneurons innervate tongue muscles and are vital for maintaining upper-airway patency during inspiration. Depression of XII nerve activity by opioid analgesics is a significant clinical problem, but underlying mechanisms are poorly understood. Currently there are no suitable pharmacological approaches to counter opiate-induced suppression of XII nerve activity while maintaining analgesia. Ampakines accentuate alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA receptor responses. The AMPA family of glutamate receptors mediate excitatory transmission to XII motoneurons. Therefore the objectives were to determine whether the depressant actions of mu-opioid receptor activation on inspiratory activity includes a direct inhibitory action at the inspiratory premotoneuron to XII motoneuron synapse, and to identify underlying mechanism(s. We then examined whether ampakines counteract opioid-induced depression of XII motoneuron activity.A medullary slice preparation from neonatal rat that produces inspiratory-related output in vitro was used. Measurements of inspiratory burst amplitude and frequency were made from XII nerve roots. Whole-cell patch recordings from XII motoneurons were used to measure membrane currents and synaptic events. Application of the mu-opioid receptor agonist, DAMGO, to the XII nucleus depressed the output of inspiratory XII motoneurons via presynaptic inhibition of excitatory glutamatergic transmission. Ampakines (CX614 and CX717 alleviated DAMGO-induced depression of XII MN activity through postsynaptic actions on XII motoneurons.The inspiratory-depressant actions of opioid analgesics include presynaptic inhibition of XII motoneuron output. Ampakines counteract mu-opioid receptor-mediated depression of XII motoneuron inspiratory activity. These results suggest that ampakines may be beneficial in countering opiate-induced suppression of XII motoneuron activity and resultant impairment of airway patency.

  7. Activation of peroxisome proliferator-activated receptor-α (PPARα) suppresses postprandial lipidemia through fatty acid oxidation in enterocytes

    Kimura, Rino; Takahashi, Nobuyuki; Murota, Kaeko; Yamada, Yuko; Niiya, Saori; Kanzaki, Noriyuki; Murakami, Yoko; Moriyama, Tatsuya; Goto, Tsuyoshi; Kawada, Teruo

    2011-01-01

    Highlights: → PPARα activation increased mRNA expression levels of fatty acid oxidation-related genes in human intestinal epithelial Caco-2 cells. → PPARα activation also increased oxygen consumption rate and CO 2 production and decreased secretion of triglyceride and ApoB from Caco-2 cells. → Orally administration of bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and CO 2 production in small intestinal epithelial cells. → Treatment with bezafibrate decreased postprandial serum concentration of triglyceride after oral injection of olive oil in mice. → It suggested that intestinal lipid metabolism regulated by PPARα activation suppresses postprandial lipidemia. -- Abstract: Activation of peroxisome proliferator-activated receptor (PPAR)-α which regulates lipid metabolism in peripheral tissues such as the liver and skeletal muscle, decreases circulating lipid levels, thus improving hyperlipidemia under fasting conditions. Recently, postprandial serum lipid levels have been found to correlate more closely to cardiovascular diseases than fasting levels, although fasting hyperlipidemia is considered an important risk of cardiovascular diseases. However, the effect of PPARα activation on postprandial lipidemia has not been clarified. In this study, we examined the effects of PPARα activation in enterocytes on lipid secretion and postprandial lipidemia. In Caco-2 enterocytes, bezafibrate, a potent PPARα agonist, increased mRNA expression levels of fatty acid oxidation-related genes, such as acyl-CoA oxidase, carnitine palmitoyl transferase, and acyl-CoA synthase, and oxygen consumption rate (OCR) and suppressed secretion levels of both triglycerides and apolipoprotein B into the basolateral side. In vivo experiments revealed that feeding high-fat-diet containing bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and production of CO 2 and acid soluble metabolites in enterocytes. Moreover

  8. Scutellarin Suppresses NLRP3 Inflammasome Activation in Macrophages and Protects Mice against Bacterial Sepsis.

    Liu, Yi; Jing, Yan-Yun; Zeng, Chen-Ying; Li, Chen-Guang; Xu, Li-Hui; Yan, Liang; Bai, Wen-Jing; Zha, Qing-Bing; Ouyang, Dong-Yun; He, Xian-Hui

    2017-01-01

    The NLRP3 inflammasome plays a critical role in mediating the innate immune defense against pathogenic infections, but aberrant activation of NLRP3 inflammasome has been linked to a variety of inflammatory diseases. Thus targeting the NLRP3 inflammasome represents a promising therapeutic for the treatment of such diseases. Scutellarin is a flavonoid isolated from Erigeron breviscapus (Vant.) Hand.-Mazz. and has been reported to exhibit potent anti-inflammatory activities, but the underlying mechanism is only partly understood. In this study, we aimed to investigate whether scutellarin could affect the activation of NLRP3 inflammasome in macrophages. The results showed that scutellarin dose-dependently reduced caspase-1 activation and decreased mature interleukin-1β (IL-1β) release in lipopolysaccharide (LPS)-primed macrophages upon ATP or nigericin stimulation, indicating that scutellarin inhibited NLRP3 inflammasome activation in macrophages. Consistent with this, scutellarin also suppressed pyroptotic cell death in LPS-primed macrophages treated with ATP or nigericin. ATP or nigericin-induced ASC speck formation and its oligomerization were blocked by scutellarin pre-treatment. Intriguingly, scutellarin augmented PKA-specific phosphorylation of NLRP3 in LPS-primed macrophages, which was completely blocked by selective PKA inhibitor H89, suggesting that PKA signaling had been involved in the action of scutellarin to suppress NLRP3 inflammasome activation. Supporting this, the inhibitory effect of scutellarin on NLRP3 inflammasome activation was completely counteracted by H89 or adenyl cyclase inhibitor MDL12330A. As NLRP3-dependent release of IL-1β has a critical role in sepsis, the in vivo activity of scutellarin was assayed in a mouse model of bacterial sepsis, which was established by intraperitoneally injection of a lethal dose of viable Escherichia coli . Oral administration of scutellarin significantly improved the survival of mice with bacterial sepsis

  9. Scutellarin Suppresses NLRP3 Inflammasome Activation in Macrophages and Protects Mice against Bacterial Sepsis

    Yi Liu

    2018-01-01

    Full Text Available The NLRP3 inflammasome plays a critical role in mediating the innate immune defense against pathogenic infections, but aberrant activation of NLRP3 inflammasome has been linked to a variety of inflammatory diseases. Thus targeting the NLRP3 inflammasome represents a promising therapeutic for the treatment of such diseases. Scutellarin is a flavonoid isolated from Erigeron breviscapus (Vant. Hand.-Mazz. and has been reported to exhibit potent anti-inflammatory activities, but the underlying mechanism is only partly understood. In this study, we aimed to investigate whether scutellarin could affect the activation of NLRP3 inflammasome in macrophages. The results showed that scutellarin dose-dependently reduced caspase-1 activation and decreased mature interleukin-1β (IL-1β release in lipopolysaccharide (LPS-primed macrophages upon ATP or nigericin stimulation, indicating that scutellarin inhibited NLRP3 inflammasome activation in macrophages. Consistent with this, scutellarin also suppressed pyroptotic cell death in LPS-primed macrophages treated with ATP or nigericin. ATP or nigericin-induced ASC speck formation and its oligomerization were blocked by scutellarin pre-treatment. Intriguingly, scutellarin augmented PKA-specific phosphorylation of NLRP3 in LPS-primed macrophages, which was completely blocked by selective PKA inhibitor H89, suggesting that PKA signaling had been involved in the action of scutellarin to suppress NLRP3 inflammasome activation. Supporting this, the inhibitory effect of scutellarin on NLRP3 inflammasome activation was completely counteracted by H89 or adenyl cyclase inhibitor MDL12330A. As NLRP3-dependent release of IL-1β has a critical role in sepsis, the in vivo activity of scutellarin was assayed in a mouse model of bacterial sepsis, which was established by intraperitoneally injection of a lethal dose of viable Escherichia coli. Oral administration of scutellarin significantly improved the survival of mice with

  10. Dihydro-CDDO-trifluoroethyl amide suppresses inflammatory responses in macrophages via activation of Nrf2

    Li, Bin; Abdalrahman, Akram; Lai, Yimu; Janicki, Joseph S.; Ward, Keith W.; Meyer, Colin J.; Wang, Xing Li; Tang, Dongqi; Cui, Taixing

    2014-01-01

    Highlights: • Dh404 suppresses the expression of a selected set of pro-inflammatory cytokines in inflamed macrophages via activating Nrf2. • Dh404 activates Nrf2 while keeping Keap1 function intact in macrophages. • Dh404 minimally regulates NF-κB pathway in macrophages. - Abstract: Nuclear factor erythroid 2-related factor (Nrf2) is the major regulator of cellular defenses against various pathological stresses in a variety of organ systems, thus Nrf2 has evolved to be an attractive drug target for the treatment and/or prevention of human disease. Several synthetic oleanolic triterpenoids including dihydro-CDDO-trifluoroethyl amide (dh404) appear to be potent activators of Nrf2 and exhibit chemopreventive promises in multiple disease models. While the pharmacological efficacy of Nrf2 activators may be dependent on the nature of Nrf2 activation in specific cell types of target organs, the precise role of Nrf2 in mediating biological effects of Nrf2 activating compounds in various cell types remains to be further explored. Herein we report a unique and Nrf2-dependent anti-inflammatory profile of dh404 in inflamed macrophages. In lipopolysaccharide (LPS)-inflamed RAW264.7 macrophages, dh404 dramatically suppressed the expression of pro-inflammatory cytokines including inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β), while minimally regulating the expression of interleulin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα). Dh404 potently activated Nrf2 signaling; however, it did not affect LPS-induced NF-κB activity. Dh404 did not interrupt the interaction of Nrf2 with its endogenous inhibitor Kelch-like ECH associating protein 1 (Keap1) in macrophages. Moreover, knockout of Nrf2 blocked the dh404-induced anti-inflammatory responses in LPS-inflamed macrophages. These results demonstrated that dh404 suppresses pro-inflammatory responses in macrophages via an activation

  11. Dihydro-CDDO-trifluoroethyl amide suppresses inflammatory responses in macrophages via activation of Nrf2

    Li, Bin [Shandong University Qilu Hospital Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital of Shandong University, Jinan 250012 (China); Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29208 (United States); Abdalrahman, Akram; Lai, Yimu; Janicki, Joseph S. [Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29208 (United States); Ward, Keith W.; Meyer, Colin J. [Department of Pharmacology, Reata Pharmaceuticals, Inc., Irving, TX 75063 (United States); Wang, Xing Li [Shandong University Qilu Hospital Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital of Shandong University, Jinan 250012 (China); Tang, Dongqi, E-mail: Dongqi.Tang@uscmed.sc.edu [Shandong University Qilu Hospital Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital of Shandong University, Jinan 250012 (China); Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29208 (United States); Cui, Taixing, E-mail: taixing.cui@uscmed.sc.edu [Shandong University Qilu Hospital Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital of Shandong University, Jinan 250012 (China); Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC 29208 (United States)

    2014-02-21

    Highlights: • Dh404 suppresses the expression of a selected set of pro-inflammatory cytokines in inflamed macrophages via activating Nrf2. • Dh404 activates Nrf2 while keeping Keap1 function intact in macrophages. • Dh404 minimally regulates NF-κB pathway in macrophages. - Abstract: Nuclear factor erythroid 2-related factor (Nrf2) is the major regulator of cellular defenses against various pathological stresses in a variety of organ systems, thus Nrf2 has evolved to be an attractive drug target for the treatment and/or prevention of human disease. Several synthetic oleanolic triterpenoids including dihydro-CDDO-trifluoroethyl amide (dh404) appear to be potent activators of Nrf2 and exhibit chemopreventive promises in multiple disease models. While the pharmacological efficacy of Nrf2 activators may be dependent on the nature of Nrf2 activation in specific cell types of target organs, the precise role of Nrf2 in mediating biological effects of Nrf2 activating compounds in various cell types remains to be further explored. Herein we report a unique and Nrf2-dependent anti-inflammatory profile of dh404 in inflamed macrophages. In lipopolysaccharide (LPS)-inflamed RAW264.7 macrophages, dh404 dramatically suppressed the expression of pro-inflammatory cytokines including inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β), while minimally regulating the expression of interleulin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα). Dh404 potently activated Nrf2 signaling; however, it did not affect LPS-induced NF-κB activity. Dh404 did not interrupt the interaction of Nrf2 with its endogenous inhibitor Kelch-like ECH associating protein 1 (Keap1) in macrophages. Moreover, knockout of Nrf2 blocked the dh404-induced anti-inflammatory responses in LPS-inflamed macrophages. These results demonstrated that dh404 suppresses pro-inflammatory responses in macrophages via an activation

  12. Prediction of P53 mutants (multiple sites transcriptional activity based on structural (2D&3D properties.

    R Geetha Ramani

    Full Text Available Prediction of secondary site mutations that reinstate mutated p53 to normalcy has been the focus of intense research in the recent past owing to the fact that p53 mutants have been implicated in more than half of all human cancers and restoration of p53 causes tumor regression. However laboratory investigations are more often laborious and resource intensive but computational techniques could well surmount these drawbacks. In view of this, we formulated a novel approach utilizing computational techniques to predict the transcriptional activity of multiple site (one-site to five-site p53 mutants. The optimal MCC obtained by the proposed approach on prediction of one-site, two-site, three-site, four-site and five-site mutants were 0.775,0.341,0.784,0.916 and 0.655 respectively, the highest reported thus far in literature. We have also demonstrated that 2D and 3D features generate higher prediction accuracy of p53 activity and our findings revealed the optimal results for prediction of p53 status, reported till date. We believe detection of the secondary site mutations that suppress tumor growth may facilitate better understanding of the relationship between p53 structure and function and further knowledge on the molecular mechanisms and biological activity of p53, a targeted source for cancer therapy. We expect that our prediction methods and reported results may provide useful insights on p53 functional mechanisms and generate more avenues for utilizing computational techniques in biological data analysis.

  13. Epigenetic mediated transcriptional activation of WNT5A participates in arsenical-associated malignant transformation

    Jensen, Taylor J.; Wozniak, Ryan J.; Eblin, Kylee E.; Wnek, Sean M.; Gandolfi, A. Jay; Futscher, Bernard W.

    2009-01-01

    Arsenic is a human carcinogen with exposure associated with cancer of the lung, skin, and bladder. Many potential mechanisms have been implicated as playing a role in the process of arsenical-induced malignancy including the perturbation of signaling pathways and aberrant epigenetic regulation. We initiated studies to examine the role of a member of the non-canonical WNT signaling pathway, WNT5A, in UROtsa cells and arsenite [URO-ASSC] and monomethylarsonous acid [URO-MSC] malignantly transformed variants. We present data herein that suggest that WNT5A is transcriptionally activated during arsenical-induced malignant transformation. This WNT5A transcriptional activation is correlated with the enrichment of permissive histone modifications and the reduction of repressive modifications in the WNT5A promoter region. The epigenetic activation of WNT5A expression and acetylation of its promoter remain after the removal of the arsenical, consistent with the maintenance of an anchorage independent growth phenotype in these cells. Additionally, treatment with epigenetic modifying drugs supports a functional role for these epigenetic marks in controlling gene expression. Reduction of WNT5A using lentiviral shRNA greatly attenuated the ability of these cells to grow in an anchorage independent fashion. Extension of our model into human bladder cancer cell lines indicates that each of the cell lines examined also express WNT5A. Taken together, these data suggest that the epigenetic remodeling of the WNT5A promoter is correlated with its transcriptional activation and this upregulation likely participates in arsenical-induced malignant transformation

  14. The artificial zinc finger coding gene 'Jazz' binds the utrophin promoter and activates transcription.

    Corbi, N; Libri, V; Fanciulli, M; Tinsley, J M; Davies, K E; Passananti, C

    2000-06-01

    Up-regulation of utrophin gene expression is recognized as a plausible therapeutic approach in the treatment of Duchenne muscular dystrophy (DMD). We have designed and engineered new zinc finger-based transcription factors capable of binding and activating transcription from the promoter of the dystrophin-related gene, utrophin. Using the recognition 'code' that proposes specific rules between zinc finger primary structure and potential DNA binding sites, we engineered a new gene named 'Jazz' that encodes for a three-zinc finger peptide. Jazz belongs to the Cys2-His2 zinc finger type and was engineered to target the nine base pair DNA sequence: 5'-GCT-GCT-GCG-3', present in the promoter region of both the human and mouse utrophin gene. The entire zinc finger alpha-helix region, containing the amino acid positions that are crucial for DNA binding, was specifically chosen on the basis of the contacts more frequently represented in the available list of the 'code'. Here we demonstrate that Jazz protein binds specifically to the double-stranded DNA target, with a dissociation constant of about 32 nM. Band shift and super-shift experiments confirmed the high affinity and specificity of Jazz protein for its DNA target. Moreover, we show that chimeric proteins, named Gal4-Jazz and Sp1-Jazz, are able to drive the transcription of a test gene from the human utrophin promoter.

  15. Localizing potentially active post-transcriptional regulations in the Ewing's sarcoma gene regulatory network

    Delyon Bernard

    2010-11-01

    Full Text Available Abstract Background A wide range of techniques is now available for analyzing regulatory networks. Nonetheless, most of these techniques fail to interpret large-scale transcriptional data at the post-translational level. Results We address the question of using large-scale transcriptomic observation of a system perturbation to analyze a regulatory network which contained several types of interactions - transcriptional and post-translational. Our method consisted of post-processing the outputs of an open-source tool named BioQuali - an automatic constraint-based analysis mimicking biologist's local reasoning on a large scale. The post-processing relied on differences in the behavior of the transcriptional and post-translational levels in the network. As a case study, we analyzed a network representation of the genes and proteins controlled by an oncogene in the context of Ewing's sarcoma. The analysis allowed us to pinpoint active interactions specific to this cancer. We also identified the parts of the network which were incomplete and should be submitted for further investigation. Conclusions The proposed approach is effective for the qualitative analysis of cancer networks. It allows the integrative use of experimental data of various types in order to identify the specific information that should be considered a priority in the initial - and possibly very large - experimental dataset. Iteratively, new dataset can be introduced into the analysis to improve the network representation and make it more specific.

  16. Regulation of WRKY46 transcription factor function by mitogen-activated protein kinases in Arabidopsis thaliana.

    Arsheed Hussain Sheikh

    2016-02-01

    Full Text Available AbstractMitogen-activated protein kinase (MAPK cascades are central signalling pathways activated in plants after sensing internal developmental and external stress cues. Knowledge about the downstream substrate proteins of MAPKs is still limited in plants. We screened Arabidopsis WRKY transcription factors as potential targets downstream of MAPKs, and concentrated on characterizing WRKY46 as a substrate of the MAPK, MPK3. Mass spectrometry revealed in vitro phosphorylation of WRKY46 at amino acid position S168 by MPK3. However, mutagenesis studies showed that a second phosphosite, S250, can also be phosphorylated. Elicitation with pathogen-associated molecular patterns (PAMPs, such as the bacterial flagellin-derived flg22 peptide led to in vivo destabilization of WRKY46 in Arabidopsis protoplasts. Mutation of either phosphorylation site reduced the PAMP-induced degradation of WRKY46. Furthermore, the protein for the double phosphosite mutant is expressed at higher levels compared to wild-type proteins or single phosphosite mutants. In line with its nuclear localization and predicted function as a transcriptional activator, overexpression of WRKY46 in protoplasts raised basal plant defence as reflected by the increase in promoter activity of the PAMP-responsive gene, NHL10, in a MAPK-dependent manner. Thus, MAPK-mediated regulation of WRKY46 is a mechanism to control plant defence.

  17. Transcriptional Activity of Nuclear Factor κB Family Genes in Patients with Systemic Sclerosis.

    Lis-Święty, Anna; Gola, Joanna; Mazurek, Urszula; Brzezińska-Wcisło, Ligia

    2017-05-01

    Systemic sclerosis (SSc) is a connective tissue disease of unknown etiology and unclear pathogenesis. Evaluation of the activation of nuclear factor κB (NF-κB) family genes IκBα, p50, p52, p65, and c-Rel, potentially involved in the regulation of immunity, inflammation, angiogenesis, and tissue remodeling in SSc, was carried out. The study included 19 patients with limited SSc, 11 patients with early SSc, and 10 healthy persons constituting the control group. Real-time QRT-PCR was used to evaluate the mRNAs in peripheral blood samples. The patients with early SSc showed a decrease in transcriptional activity of IκBα inhibitor and c-Rel subunit. Transcriptional activity decrease in the other patients with limited SSc included genes encoding c-Rel and p50, subunits of NF-κB factor. Deregulation of intracellular signal transduction by NF-κB takes place at the beginning of SSc and in its fibrosis stage. Associations between clinical variables and NF-κB related gene expression as well as the activation of NF-κB family members in SSc patients should be addressed in future studies. © 2017 by the Association of Clinical Scientists, Inc.

  18. ZFP226 is a novel artificial transcription factor for selective activation of tumor suppressor KIBRA.

    Schelleckes, Katrin; Schmitz, Boris; Lenders, Malte; Mewes, Mirja; Brand, Stefan-Martin; Brand, Eva

    2018-03-09

    KIBRA has been suggested as a key regulator of the hippo pathway, regulating organ size, cell contact inhibition as well as tissue regeneration and tumorigenesis. Recently, alterations of KIBRA expression caused by promotor methylation have been reported for several types of cancer. Our current study aimed to design an artificial transcription factor capable of re-activating expression of the tumor suppressor KIBRA and the hippo pathway. We engineered a new gene named 'ZFP226' encoding for a ~23 kDa fusion protein. ZFP226 belongs to the Cys2-His2 zinc finger type and recognizes a nine base-pair DNA sequence 5'-GGC-GGC-GGC-3' in the KIBRA core promoter P1a. ZFP226 showed nuclear localization in human immortalized kidney epithelial cells and activated the KIBRA core promoter (p < 0.001) resulting in significantly increased KIBRA mRNA and protein levels (p < 0.001). Furthermore, ZFP226 led to activation of hippo signaling marked by elevated YAP and LATS phosphorylation. In Annexin V flow cytometry assays ZFP226 overexpression showed strong pro-apoptotic capacity on MCF-7 breast cancer cells (p < 0.01 early-, p < 0.001 late-apoptotic cells). We conclude that the artificial transcription factor ZFP226 can be used for target KIBRA and hippo pathway activation. This novel molecule may represent a molecular tool for the development of future applications in cancer treatment.

  19. Active background suppression with the liquid argon scintillation veto of GERDA Phase II

    Agostini, M.; Allardt, M.; Bakalyarov, A. M.; Balata, M.; Barabanov, I.; Baudis, L.; Bauer, C.; Bellotti, E.; Belogurov, S.; Belyaev, S. T.; Benato, G.; Bettini, A.; Bezrukov, L.; Bode, T.; Borowicz, D.; Brudanin, V.; Brugnera, R.; Caldwell, A.; Cattadori, C.; Chernogorov, A.; D'Andrea, V.; Demidova, E. V.; Di Marco, N.; Domula, A.; Doroshkevich, E.; Egorov, V.; Falkenstein, R.; Frodyma, N.; Gangapshev, A.; Garfagnini, A.; Gooch, C.; Grabmayr, P.; Gurentsov, V.; Gusev, K.; Hakenmüller, J.; Hegai, A.; Heisel, M.; Hemmer, S.; Hofmann, W.; Hult, M.; Inzhechik, L. V.; Janicskó Csáthy, J.; Jochum, J.; Junker, M.; Kazalov, V.; Kihm, T.; Kirpichnikov, I. V.; Kirsch, A.; Kish, A.; Klimenko, A.; Kneißl, R.; Knöpfle, K. T.; Kochetov, O.; Kornoukhov, V. N.; Kuzminov, V. V.; Laubenstein, M.; Lazzaro, A.; Lebedev, V. I.; Lehnert, B.; Liao, H. Y.; Lindner, M.; Lippi, I.; Lubashevskiy, A.; Lubsandorzhiev, B.; Lutter, G.; Macolino, C.; Majorovits, B.; Maneschg, W.; Medinaceli, E.; Miloradovic, M.; Mingazheva, R.; Misiaszek, M.; Moseev, P.; Nemchenok, I.; Palioselitis, D.; Panas, K.; Pandola, L.; Pelczar, K.; Pullia, A.; Riboldi, S.; Rumyantseva, N.; Sada, C.; Salamida, F.; Salathe, M.; Schmitt, C.; Schneider, B.; Schönert, S.; Schreiner, J.; Schulz, O.; Schütz, A.-K.; Schwingenheuer, B.; Selivanenko, O.; Shevzik, E.; Shirchenko, M.; Simgen, H.; Smolnikov, A.; Stanco, L.; Vanhoefer, L.; Vasenko, A. A.; Veresnikova, A.; von Sturm, K.; Wagner, V.; Wegmann, A.; Wester, T.; Wiesinger, C.; Wojcik, M.; Yanovich, E.; Zhitnikov, I.; Zhukov, S. V.; Zinatulina, D.; Zuber, K.; Zuzel, G.

    2017-09-01

    The observation of neutrinoless double beta decay would allow to shed light onto the particle nature of neutrinos. Gerda is aiming to perform a background-free search for this process using high purity germanium detectors enriched in 76Ge operated in liquid argon. This goal relies on the application of active background suppression techniques. A low background light instrumentation has been installed for Phase II to detect events with coincident energy deposition in the nearby liquid argon. The intended background index of ˜10-3 cts/(keV·ky·yr) has been confirmed.

  20. Chaos suppression via observer based active control scheme: Application to Duffing's oscillator

    Aguilar-Lopez, Ricardo; Martinez-Guerra, Rafael

    2007-01-01

    The aim of this paper is the synthesis of a robust control law for chaos suppression of a class of non-linear oscillator with affine control input. A robust state observer based active controller, which provides robustness against model uncertainties and noisy output measurements is proposed. The closed-loop stability for the underlying closed-loop system is done via the regulation and estimation errors dynamics. The performance of the proposed control law is illustrated with numerical simulations. The method is general and can be applied to various non-linear systems which satisfy the conditions required

  1. Chaos suppression via observer based active control scheme: Application to Duffing's oscillator

    Aguilar-Lopez, Ricardo [Departamento de Energia, Universidad Autonoma Metropolita-Azcapotzalco, Av. San Pablo No. 180, Reynosa-Tamaulipas, Azcapotzalco 02200, Mexico DF (Mexico)]. E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, Rafael [Departamento de Control Automatico, CINVESTAV-IPN, C.P. 07360 Mexico DF (Mexico)

    2007-06-15

    The aim of this paper is the synthesis of a robust control law for chaos suppression of a class of non-linear oscillator with affine control input. A robust state observer based active controller, which provides robustness against model uncertainties and noisy output measurements is proposed. The closed-loop stability for the underlying closed-loop system is done via the regulation and estimation errors dynamics. The performance of the proposed control law is illustrated with numerical simulations. The method is general and can be applied to various non-linear systems which satisfy the conditions required.

  2. Butyrate transcriptionally enhances peptide transporter PepT1 expression and activity.

    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.

  3. Specificity and transcriptional activity of microbiota associated with low and high microbial abundance sponges from the Red Sea

    Moitinho-Silva, Lucas; Bayer, Kristina; Cannistraci, Carlo; Giles, Emily; Ryu, Tae Woo; Seridi, Loqmane; Ravasi, Timothy; Hentschel, Ute T E

    2013-01-01

    Marine sponges are generally classified as high microbial abundance (HMA) and low microbial abundance (LMA) species. Here, 16S rRNA amplicon sequencing was applied to investigate the diversity, specificity and transcriptional activity of microbes

  4. Fisetin inhibits epidermal growth factor–induced migration of ARPE-19 cells by suppression of AKT activation and Sp1-dependent MMP-9 expression

    Lin, Hung-Yu; Chen, Yong-Syuan; Wang, Kai; Chien, Hsiang-Wen

    2017-01-01

    Purpose Proliferative vitreoretinopathy (PVR) can result in abnormal migration of RPE cells. Fisetin is a naturally occurring compound that has been reported to have antitumor effects, but its effects on epidermal growth factor (EGF)–induced cell migration and the underlying mechanisms remain unclear. Methods Effects of fisetin on EGF-induced cell viability and migration were examined with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and in vitro migration assays. Reverse transcription–PCR (RT–PCR) and immunoblotting were performed to evaluate matrix metallopeptidase-9 (MMP-9) expression and activation of specificity protein-1 (Sp1) and protein kinase B (AKT) in ARPE-19 cells treated with EGF and with or without fisetin. Luciferase and chromatin immunoprecipitation (ChIP) assays were performed to examine Sp1 transcription activity and MMP-9 binding activity. Results Fisetin did not affect ARPE-19 cell viability and significantly inhibited the EGF-induced migration capacity of ARPE-19 cells. Furthermore, fisetin exerted an antimigratory effect and suppressed MMP-9 mRNA and protein expression. Treatment with EGF induced phosphorylation of AKT and expression of MMP-9 and Sp1. Fisetin combined with LY294002 (an inhibitor of AKT) prevented the EGF-induced migration involved in downregulation of Sp1 and MMP-9 expression. Luciferase and ChIP assays suggested that fisetin remarkably decreased the EGF-induced transcription activity of MMP-9 and Sp1 and inhibited EGF-mediated Sp1 from directly binding to the MMP-9 promoter in ARPE-19 cells. Conclusions Fisetin inhibited EGF-induced cell migration via modulation of AKT/Sp1–dependent MMP-9 transcriptional activity. Therefore, fisetin may be a potential agent in the treatment of migratory PVR diseases. PMID:29296070

  5. Inhibition of FoxO transcriptional activity prevents muscle fiber atrophy during cachexia and induces hypertrophy

    Reed, Sarah A.; Sandesara, Pooja B.; Senf, Sarah M.; Judge, Andrew R.

    2012-01-01

    Cachexia is characterized by inexorable muscle wasting that significantly affects patient prognosis and increases mortality. Therefore, understanding the molecular basis of this muscle wasting is of significant importance. Recent work showed that components of the forkhead box O (FoxO) pathway are increased in skeletal muscle during cachexia. In the current study, we tested the physiological significance of FoxO activation in the progression of muscle atrophy associated with cachexia. FoxO-DNA binding dependent transcription was blocked in the muscles of mice through injection of a dominant negative (DN) FoxO expression plasmid prior to inoculation with Lewis lung carcinoma cells or the induction of sepsis. Expression of DN FoxO inhibited the increased mRNA levels of atrogin-1, MuRF1, cathepsin L, and/or Bnip3 and inhibited muscle fiber atrophy during cancer cachexia and sepsis. Interestingly, during control conditions, expression of DN FoxO decreased myostatin expression, increased MyoD expression and satellite cell proliferation, and induced fiber hypertrophy, which required de novo protein synthesis. Collectively, these data show that FoxO-DNA binding-dependent transcription is necessary for normal muscle fiber atrophy during cancer cachexia and sepsis, and further suggest that basal levels of FoxO play an important role during normal conditions to depress satellite cell activation and limit muscle growth.—Reed, S. A., Sandesara, P. B., Senf, S. F., Judge, A. R. Inhibition of FoxO transcriptional activity prevents muscle fiber atrophy during cachexia and induces hypertrophy. PMID:22102632

  6. Differential binding activity of the transcription factor LIL-Stat in immature and differentiated normal and leukemic myeloid cells

    Tuyt, LML; Bregman, K; Lummen, C; Dokter, WHA; Vellenga, E

    1998-01-01

    Cytokines and growth factors induce activation of the family of signal transducers and activators of transcription (Stats) that directly activate gene expression. Recently, constitutively activated Stat1, Stat3, and Stat5 were identified in nuclear extracts of acute myeloid leukemia (AML) patients,

  7. Transcriptional activation of NAD+-dependent protein deacetylase SIRT1 by nuclear receptor TLX.

    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.

  8. Transcriptional activation of NAD+-dependent protein deacetylase SIRT1 by nuclear receptor TLX

    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.

  9. Linderane Suppresses Hepatic Gluconeogenesis by Inhibiting the cAMP/PKA/CREB Pathway Through Indirect Activation of PDE 3 via ERK/STAT3

    Wei Xie

    2018-05-01

    Full Text Available The role of phosphodiesterase 3 (PDE3, a cyclic AMP (cAMP-degrading enzyme, in modulating gluconeogenesis remains unknown. Here, linderane, a natural compound, was found to inhibit gluconeogenesis by activating hepatic PDE3 in rat primary hepatocytes. The underlying molecular mechanism and its effects on whole-body glucose and lipid metabolism were investigated. The effect of linderane on gluconeogenesis, cAMP content, phosphorylation of cAMP-response element-binding protein (CREB and PDE activity were examined in cultured primary hepatocytes and C57BL/6J mice. The precise mechanism by which linderane activates PDE3 and inhibits the cAMP pathway was explored using pharmacological inhibitors. The amelioration of metabolic disorders was observed in ob/ob mice. Linderane inhibited gluconeogenesis, reduced phosphoenolpyruvate carboxykinase (Pck1 and glucose-6-phosphatase (G6pc gene expression, and decreased intracellular cAMP concentration and CREB phosphorylation in rat primary hepatocytes under both basal and forskolin-stimulated conditions. In rat primary hepatocytes, it also increased total PDE and PDE3 activity but not PDE4 activity. The suppressive effect of linderane on the cAMP pathway and gluconeogenesis was abolished by the non-specific PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX and the specific PDE3 inhibitor cilostazol. Linderane indirectly activated PDE3 through extracellular regulated protein kinase 1/2 (ERK1/2 and signal transducer and activator of transcription 3 (STAT3 activation. Linderane improved glucose and lipid metabolism after chronic oral administration in ob/ob mice. Our findings revealed linderane as an indirect PDE3 activator that suppresses gluconeogenesis through cAMP pathway inhibition and has beneficial effects on metabolic syndromes in ob/ob mice. This investigation highlighted the potential for PDE3 activation in the treatment of type 2 diabetes.

  10. Insulators target active genes to transcription factories and polycomb-repressed genes to polycomb bodies.

    Hua-Bing Li

    2013-04-01

    Full Text Available Polycomb bodies are foci of Polycomb proteins in which different Polycomb target genes are thought to co-localize in the nucleus, looping out from their chromosomal context. We have shown previously that insulators, not Polycomb response elements (PREs, mediate associations among Polycomb Group (PcG targets to form Polycomb bodies. Here we use live imaging and 3C interactions to show that transgenes containing PREs and endogenous PcG-regulated genes are targeted by insulator proteins to different nuclear structures depending on their state of activity. When two genes are repressed, they co-localize in Polycomb bodies. When both are active, they are targeted to transcription factories in a fashion dependent on Trithorax and enhancer specificity as well as the insulator protein CTCF. In the absence of CTCF, assembly of Polycomb bodies is essentially reduced to those representing genomic clusters of Polycomb target genes. The critical role of Trithorax suggests that stable association with a specialized transcription factory underlies the cellular memory of the active state.

  11. Structural Features and Transcriptional Activity of Chicken PPARs (α, β, and γ

    Ichiro Takada

    2013-01-01

    Full Text Available While an understanding of lipid metabolism in chickens is critical for a further improvement of food production, there are few studies concerning differences in lipid metabolism mechanisms between chickens and other species at a molecular level. Chickens have three PPAR gene subtypes (α, β, and γ that function differently from those present in humans and mice. The chicken PPAR-gamma (cPPARγ gene is shorter than that in humans and lacks a γ2 isoform. Moreover, in serum-free media, cPPARγ shows high transcriptional activity without exogenous ligands. Luciferase reporter assays were used to examine the effect of sera on cPPAR transcriptional activities and showed that adult bovine serum and chicken serum highly activate cPPARα and β functions. Moreover, we found that bezafibrate induces the transactivation function of cPPARβ, but not human PPARδ (human PPARβ ortholog. This ligand selectivity relies on one amino acid residue (chicken: Val419, human: Met444. These results show the possibilities for unique functions of cPPARs on chicken-specific lipid glucose metabolism. As such, a better understanding of the molecular mechanisms of lipid metabolism in chickens could result in higher productivity for the poultry industry.

  12. A novel telomerase activator suppresses lung damage in a murine model of idiopathic pulmonary fibrosis.

    Le Saux, Claude Jourdan; Davy, Philip; Brampton, Christopher; Ahuja, Seema S; Fauce, Steven; Shivshankar, Pooja; Nguyen, Hieu; Ramaseshan, Mahesh; Tressler, Robert; Pirot, Zhu; Harley, Calvin B; Allsopp, Richard

    2013-01-01

    The emergence of diseases associated with telomere dysfunction, including AIDS, aplastic anemia and pulmonary fibrosis, has bolstered interest in telomerase activators. We report identification of a new small molecule activator, GRN510, with activity ex vivo and in vivo. Using a novel