Cell cycle-regulated expression of mammalian CDC6 is dependent on E2F

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Hateboer, G; Wobst, A; Petersen, B O

1998-01-01

The E2F transcription factors are essential regulators of cell growth in multicellular organisms, controlling the expression of a number of genes whose products are involved in DNA replication and cell proliferation. In Saccharomyces cerevisiae, the MBF and SBF transcription complexes have...... of this gene is dependent on E2F. In vivo footprinting data demonstrate that the identified E2F sites are occupied in resting cells and in exponentially growing cells, suggesting that E2F is responsible for downregulating the promoter in early phases of the cell cycle and the subsequent upregulation when cells...

E2F1-Mediated Induction of NFYB Attenuates Apoptosis via Joint Regulation of a Pro-Survival Transcriptional Program.

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Xiaolei Jiang

Full Text Available The E2F1 transcription factor regulates cell proliferation and apoptosis through the control of a considerable variety of target genes. Previous work has detailed the role of other transcription factors in mediating the specificity of E2F function. Here we identify the NF-YB transcription factor as a novel direct E2F1 target. Genome-wide expression analysis of the effects of NFYB knockdown on E2F1-mediated transcription identified a large group of genes that are co-regulated by E2F1 and NFYB. We also provide evidence that knockdown of NFYB enhances E2F1-induced apoptosis, suggesting a pro-survival function of the NFYB/E2F1 joint transcriptional program. Bioinformatic analysis suggests that deregulation of these NFY-dependent E2F1 target genes might play a role in sarcomagenesis as well as drug resistance.

Regulation of the voltage-gated Ca2+ channel CaVα2δ-1 subunit expression by the transcription factor Egr-1.

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González-Ramírez, Ricardo; Martínez-Hernández, Elizabeth; Sandoval, Alejandro; Gómez-Mora, Kimberly; Felix, Ricardo

2018-04-23

It is well known that the Ca V α 2 δ auxiliary subunit regulates the density of high voltage-activated Ca 2+ channels in the plasma membrane and that alterations in their functional expression might have implications in the pathophysiology of diverse human diseases such as neuropathic pain. However, little is known concerning the transcriptional regulation of this protein. We previously characterized the promoter of Ca V α 2 δ, and here we report its regulation by the transcription factor Egr-1. Using the neuroblastoma N1E-115 cells, we found that Egr-1 interacts specifically with its binding site in the promoter, affecting the transcriptional regulation of Ca V α 2 δ. Overexpression and knockdown analysis of Egr-1 showed significant changes in the transcriptional activity of the Ca V α 2 δ promoter. Egr-1 also regulated the expression of Ca V α 2 δ at the level of protein. Also, functional studies showed that Egr-1 knockdown significantly decreases Ca 2+ currents in dorsal root ganglion (DRG) neurons, while overexpression of the transcription factor increased Ca 2+ currents in the F11 cell line, a hybrid of DRG and N18TG2 neuroblastoma cells. Studying the effects of Egr-1 on the transcriptional expression of Ca V α 2 δ could help to understand the regulatory mechanisms of this protein in both health and disease. Copyright © 2018 Elsevier B.V. All rights reserved.

E2F1 and E2F2 induction in response to DNA damage preserves genomic stability in neuronal cells.

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Castillo, Daniela S; Campalans, Anna; Belluscio, Laura M; Carcagno, Abel L; Radicella, J Pablo; Cánepa, Eduardo T; Pregi, Nicolás

2015-01-01

E2F transcription factors regulate a wide range of biological processes, including the cellular response to DNA damage. In the present study, we examined whether E2F family members are transcriptionally induced following treatment with several genotoxic agents, and have a role on the cell DNA damage response. We show a novel mechanism, conserved among diverse species, in which E2F1 and E2F2, the latter specifically in neuronal cells, are transcriptionally induced after DNA damage. This upregulation leads to increased E2F1 and E2F2 protein levels as a consequence of de novo protein synthesis. Ectopic expression of these E2Fs in neuronal cells reduces the level of DNA damage following genotoxic treatment, while ablation of E2F1 and E2F2 leads to the accumulation of DNA lesions and increased apoptotic response. Cell viability and DNA repair capability in response to DNA damage induction are also reduced by the E2F1 and E2F2 deficiencies. Finally, E2F1 and E2F2 accumulate at sites of oxidative and UV-induced DNA damage, and interact with γH2AX DNA repair factor. As previously reported for E2F1, E2F2 promotes Rad51 foci formation, interacts with GCN5 acetyltransferase and induces histone acetylation following genotoxic insult. The results presented here unveil a new mechanism involving E2F1 and E2F2 in the maintenance of genomic stability in response to DNA damage in neuronal cells.

Adrenomedullin Regulates IL-1β Gene Expression in F4/80+ Macrophages during Synovial Inflammation

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Takano, Shotaro; Miyagi, Masayuki; Inoue, Gen; Aikawa, Jun; Iwabuchi, Kazuya; Takaso, Masashi

2017-01-01

Adrenomedullin (AM) plays an important role in the regulation of inflammatory processes; however, the role and expression of AM in synovial inflammation have not been determined. To investigate the expression and role of AM in inflamed synovial tissue (ST), the gene expression profiles of AM in the ST, including synovial macrophages and fibroblasts, of a murine patellar surgical dislocation model were characterized. In addition, the effects of interleukin- (IL-) 1β and AM in cultured synovial cells were also examined. CD11c+ macrophages were found to be elevated in ST of the surgically dislocated patella. Higher gene expression of CD11c, IL-1β, AM, receptor activity-modifying proteins 2 (RAMP2), and 3 (RAMP3) was also observed in ST obtained from the dislocated side. AM expression was also significantly increased in synovial fibroblasts and macrophages in response to IL-1β treatment. Synovial macrophages also highly expressed RAMP3 compared to fibroblasts and this expression was further stimulated by exogenously added IL-1β. Further, the treatment of the F4/80-positive cell fraction obtained from ST with AM inhibited IL-1β expression. Taken together, these findings demonstrated that AM was produced by synovial fibroblasts and macrophages in inflamed ST and that increased levels of AM may exert anti-inflammatory effects on synovial macrophages. PMID:28299347

Knockdown of E2f1 by RNA interference impairs proliferation of rat cells in vitro

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Luciana dos Reis Vasques

2010-01-01

Full Text Available E2F1 plays a key role in cell-cycle regulation in mammals, since its transcription factor activity controls genes required for DNA synthesis and apoptosis. E2F1 deregulation is a common feature among different tumor types and can be a major cause of cell proliferation. Thus, blocking E2F1 expression by RNA interference represents a promising therapeutic approach. In this study, the introduction of specific short hairpin RNAs (shRNAs reduced E2f1 expression by up to 77%, and impaired rat glioma cell proliferation by approximately 70%, as compared to control cells. Furthermore, we investigated the expression of E2f1 target genes, Cyclin A and Cyclin E. Cyclin A was found to be down-regulated, whereas Cyclin E had similar expression to control cells, indicating that gene(s other than E2f1 control its transcription. Other E2f family members, E2f2 and E2f3, which have been classified in the same subgroup of transcriptional activators, were also analyzed. Expression of both E2f2 and E2f3 was similar to control cells, showing no cross-inactivation or up-regulation to compensate for the absence of E2f1. Nevertheless, their expression was insufficient to maintain the initial proliferation potential. Taken together, our results suggest that shE2f1 is a promising therapy to control tumor cell proliferation.

Expression and Functional Pathway Analysis of Nuclear Receptor NR2F2 in Ovarian Cancer

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Hawkins, Shannon M.; Loomans, Holli A.; Wan, Ying-Wooi; Ghosh-Choudhury, Triparna; Coffey, Donna; Xiao, Weimin; Liu, Zhandong; Sangi-Haghpeykar, Haleh

2013-01-01

Context: Recent evidence implicates the orphan nuclear receptor, nuclear receptor subfamily 2, group F, member 2 (NR2F2; chicken ovalbumin upstream promoter-transcription factor II) as both a master regulator of angiogenesis and an oncogene in prostate and other human cancers. Objective: The objective of the study was to determine whether NR2F2 plays a role in ovarian cancer and dissect its potential mechanisms of action. Design, Setting, and Patients: We examined NR2F2 expression in healthy ovary and ovarian cancers using quantitative PCR and immunohistochemistry. NR2F2 expression was targeted in established ovarian cancer cell lines to assess the impact of dysregulated NR2F2 expression in the epithelial compartment of ovarian cancers. Results: Our results indicate that NR2F2 is robustly expressed in the stroma of healthy ovary with little or no expression in epithelia lining the ovarian surface, clefts, or crypts. This pattern of NR2F2 expression was markedly disrupted in ovarian cancers, in which decreased levels of stromal expression and ectopic epithelial expression were frequently observed. Ovarian cancers with the most disrupted patterns of NR2F2 were associated with significantly shorter disease-free interval by Kaplan-Meier analysis. Targeting NR2F2 expression in established ovarian cancer cell lines enhanced apoptosis and increased proliferation. In addition, we found that NR2F2 regulates the expression of NEK2, RAI14, and multiple other genes involved in the cell cycle, suggesting potential pathways by which dysregulated expression of NR2F2 impacts ovarian cancer. Conclusions: These results uncover novel roles for NR2F2 in ovarian cancer and point to a unique scenario in which a single nuclear receptor plays potentially distinct roles in the stromal and epithelial compartments of the same tissue. PMID:23690307

E2F family members are differentially regulated by reversible acetylation

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Marzio, G; Wagener, C; Gutierrez, M I

2000-01-01

of the other E2F family members. Here we report that E2F-1, -2, and -3, but not E2F-4, -5, and -6, associate with and are acetylated by p300 and cAMP-response element-binding protein acetyltransferases. Acetylation occurs at three conserved lysine residues located at the N-terminal boundary of their DNA......The six members of the E2F family of transcription factors play a key role in the control of cell cycle progression by regulating the expression of genes involved in DNA replication and cell proliferation. E2F-1, -2, and -3 belong to a structural and functional subfamily distinct from those...

The Cdk4-E2f1 pathway regulates early pancreas development by targeting Pdx1+ progenitors and Ngn3+ endocrine precursors

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Kim, So Yoon; Rane, Sushil G.

2011-01-01

Cell division and cell differentiation are intricately regulated processes vital to organ development. Cyclin-dependent kinases (Cdks) are master regulators of the cell cycle that orchestrate the cell division and differentiation programs. Cdk1 is essential to drive cell division and is required for the first embryonic divisions, whereas Cdks 2, 4 and 6 are dispensable for organogenesis but vital for tissue-specific cell development. Here, we illustrate an important role for Cdk4 in regulating early pancreas development. Pancreatic development involves extensive morphogenesis, proliferation and differentiation of the epithelium to give rise to the distinct cell lineages of the adult pancreas. The cell cycle molecules that specify lineage commitment within the early pancreas are unknown. We show that Cdk4 and its downstream transcription factor E2f1 regulate mouse pancreas development prior to and during the secondary transition. Cdk4 deficiency reduces embryonic pancreas size owing to impaired mesenchyme development and fewer Pdx1+ pancreatic progenitor cells. Expression of activated Cdk4R24C kinase leads to increased Nkx2.2+ and Nkx6.1+ cells and a rise in the number and proliferation of Ngn3+ endocrine precursors, resulting in expansion of the β cell lineage. We show that E2f1 binds and activates the Ngn3 promoter to modulate Ngn3 expression levels in the embryonic pancreas in a Cdk4-dependent manner. These results suggest that Cdk4 promotes β cell development by directing E2f1-mediated activation of Ngn3 and increasing the pool of endocrine precursors, and identify Cdk4 as an important regulator of early pancreas development that modulates the proliferation potential of pancreatic progenitors and endocrine precursors. PMID:21490060

Expression of FLNa in human melanoma cells regulates the function of integrin α1β1 and phosphorylation and localisation of PKB/AKT/ERK1/2 kinases.

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Krebs, Kristi; Ruusmann, Anu; Simonlatser, Grethel; Velling, Teet

2015-12-01

FLNa is a ubiquitous cytoskeletal protein that links transmembrane receptors, including integrins, to F-actin and functions as a signalling intermediate. We investigated FLNa's role in the function of integrin-type collagen receptors, EGF-EGFR signalling and regulation of PKB/Akt and ERK1/2. Using FLNa-deficient M2 human melanoma cells, and same cells expressing EGFP-FLNa (M2F) or its Ig-like repeats 1-8+24, 8-15+24 and 16-24, we found that in M2F and M2 8-15+24 cells, EGF induced the increased phosphorylation of PKB/Akt and ERK1/2. In M2F cells EGF induced the localisation of these kinases to cell nucleus and lamellipodia, respectively, and the ERK1/2 phosphorylation-dependent co-immunoprecipitation of FLNa with ERK1/2. Only M2F and M2 8-15+24 cells adhered to and spread on type I collagen whereas on fibronectin all cells behaved similarly. α1β1 and α2β1 were the integrin-type collagen receptors expressed on these cells with primarily α1β1 localising to focal contacts and affecting cell adhesion and migration in a manner dependent on FLNa or its Ig-like repeats 8-15. Our results suggest a role for FLNa repeats 8-15 in the α1-subunit-dependent regulation of integrin α1β1 function, EGF-EGFR signalling to PKB/Akt and ERK1/2, identify ERK1/2 in EGF-induced FLNa-associated protein complexes, and show that the function of different integrins is subjected to differential regulation by FLNa. Copyright © 2015. Published by Elsevier GmbH.

KDM4A Coactivates E2F1 to Regulate the PDK-Dependent Metabolic Switch between Mitochondrial Oxidation and Glycolysis

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Ling-Yu Wang

2016-09-01

Full Text Available The histone lysine demethylase KDM4A/JMJD2A has been implicated in prostate carcinogenesis through its role in transcriptional regulation. Here, we describe KDM4A as a E2F1 coactivator and demonstrate a functional role for the E2F1-KDM4A complex in the control of tumor metabolism. KDM4A associates with E2F1 on target gene promoters and enhances E2F1 chromatin binding and transcriptional activity, thereby modulating the transcriptional profile essential for cancer cell proliferation and survival. The pyruvate dehydrogenase kinases (PDKs PDK1 and PDK3 are direct targets of KDM4A and E2F1 and modulate the switch between glycolytic metabolism and mitochondrial oxidation. Downregulation of KDM4A leads to elevated activity of pyruvate dehydrogenase and mitochondrial oxidation, resulting in excessive accumulation of reactive oxygen species. The altered metabolic phenotypes can be partially rescued by ectopic expression of PDK1 and PDK3, indicating a KDM4A-dependent tumor metabolic regulation via PDK. Our results suggest that KDM4A is a key regulator of tumor metabolism and a potential therapeutic target for prostate cancer.

The C-terminal domain of Nrf1 negatively regulates the full-length CNC-bZIP factor and its shorter isoform LCR-F1/Nrf1β; both are also inhibited by the small dominant-negative Nrf1γ/δ isoforms that down-regulate ARE-battery gene expression.

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Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

2014-01-01

The C-terminal domain (CTD, aa 686-741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ.

Transcriptional regulation of BRD7 expression by Sp1 and c-Myc

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Li Shufang

2008-12-01

Full Text Available Abstract Background Bromodomain is an evolutionally conserved domain that is found in proteins strongly implicated in signal-dependent transcriptional regulation. Genetic alterations of bromodomain genes contributed to the development of many human cancers and other disorders. BRD7 is a recently identified bromodomain gene. It plays a critical role in cellular growth, cell cycle progression, and signal-dependent gene expression. Previous studies showed that BRD7 gene exhibited much higher-level of mRNA expression in normal nasopharyngeal epithelia than in nasopharyngeal carcinoma (NPC biopsies and cell lines. However, little is known about its transcriptional regulation. In this study, we explored the transcriptional regulation of BRD7 gene. Method Potential binding sites of transcription factors within the promoter region of BRD7 gene were predicted with MatInspector Professional http://genomatix.de/cgi-bin/matinspector_prof/mat_fam.pl. Mutation construct methods and luciferase assays were performed to define the minimal promoter of BRD7 gene. RT-PCR and western blot assays were used to detect the endogenous expression of transcription factor Sp1, c-Myc and E2F6 in all cell lines used in this study. Electrophoretic mobility shift assays (EMSA and Chromatin immunoprecipitation (ChIP were used to detect the direct transcription factors that are responsible for the promoter activity of BRD7 gene. DNA vector-based siRNA technology and cell transfection methods were employed to establish clone pools that stably expresses SiRNA against c-Myc expression in nasopharyngeal carcinoma 5-8F cells. Real-time PCR was used to detect mRNA expression of BRD7 gene in 5-8F/Si-c-Myc cells. Results We defined the minimal promoter of BRD7 gene in a 55-bp region (from -266 to -212bp, and identified that its promoter activity is inversely related to c-Myc expression. Sp1 binds to the Sp1/Myc-Max overlapping site of BRD7 minimal promoter, and slightly positively

Influenza A virus protein PB1-F2 exacerbates IFN-beta expression of human respiratory epithelial cells.

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Le Goffic, Ronan; Bouguyon, Edwige; Chevalier, Christophe; Vidic, Jasmina; Da Costa, Bruno; Leymarie, Olivier; Bourdieu, Christiane; Decamps, Laure; Dhorne-Pollet, Sophie; Delmas, Bernard

2010-10-15

The PB1-F2 protein of the influenza A virus (IAV) contributes to viral pathogenesis by a mechanism that is not well understood. PB1-F2 was shown to modulate apoptosis and to be targeted by the CD8(+) T cell response. In this study, we examined the downstream effects of PB1-F2 protein during IAV infection by measuring expression of the cellular genes in response to infection with wild-type WSN/33 and PB1-F2 knockout viruses in human lung epithelial cells. Wild-type virus infection resulted in a significant induction of genes involved in innate immunity. Knocking out the PB1-F2 gene strongly decreased the magnitude of expression of cellular genes implicated in antiviral response and MHC class I Ag presentation, suggesting that PB1-F2 exacerbates innate immune response. Biological network analysis revealed the IFN pathway as a link between PB1-F2 and deregulated genes. Using quantitative RT-PCR and IFN-β gene reporter assay, we determined that PB1-F2 mediates an upregulation of IFN-β expression that is dependent on NF-κB but not on AP-1 and IFN regulatory factor-3 transcription factors. Recombinant viruses knocked out for the PB1-F2 and/or the nonstructural viral protein 1 (the viral antagonist of the IFN response) genes provide further evidence that PB1-F2 increases IFN-β expression and that nonstructural viral protein 1 strongly antagonizes the effect of PB1-F2 on the innate response. Finally, we compared the effect of PB1-F2 variants taken from several IAV strains on IFN-β expression and found that PB1-F2-mediated IFN-β induction is significantly influenced by its amino acid sequence, demonstrating its importance in the host cell response triggered by IAV infection.

The spatial expression and regulation of transcription factors IDEF1 and IDEF2

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Kobayashi, Takanori; Ogo, Yuko; Aung, May Sann; Nozoye, Tomoko; Itai, Reiko Nakanishi; Nakanishi, Hiromi; Yamakawa, Takashi; Nishizawa, Naoko K.

2010-01-01

Background and Aims Under conditions of low iron availability, rice plants induce genes involved in iron uptake and utilization. The iron deficiency-responsive cis-acting element binding factors 1 and 2 (IDEF1 and IDEF2) regulate transcriptional response to iron deficiency in rice roots. Clarification of the functions of IDEF1 and IDEF2 could uncover the gene regulation mechanism. Methods Spatial patterns of IDEF1 and IDEF2 expression were analysed by histochemical staining of IDEF1 and IDEF2 promoter-GUS transgenic rice lines. Expression patterns of the target genes of IDEF1 and IDEF2 were analysed using transformants with induced or repressed expression of IDEF1 or IDEF2 grown in iron-rich or in iron-deficient solutions for 1 d. Key Results IDEF1 and IDEF2 were highly expressed in the basal parts of the lateral roots and vascular bundles. IDEF1 and IDEF2 expression was dominant in leaf mesophyll and vascular cells, respectively. These expression patterns were similar under both iron-deficient and iron-sufficient conditions. IDEF1 was strongly expressed in pollen, ovaries, the aleurone layer and embryo. IDEF2 was expressed in pollen, ovaries and the dorsal vascular region of the endosperm. During seed germination, IDEF1 and IDEF2 were expressed in the endosperm and embryo. Expression of IDEF1 target genes was regulated in iron-rich roots similar to early iron-deficiency stages. In addition, the expression patterns of IDEF2 target genes were similar between iron-rich conditions and early or subsequent iron deficiency. Conclusions IDEF1 and IDEF2 are constitutively expressed during both vegetative and reproductive stages. The spatial expression patterns of IDEF1 and IDEF2 overlap with their target genes in restricted cell types, but not in all cells. The spatial expression patterns and gene regulation of IDEF1 and IDEF2 in roots are generally conserved under conditions of iron sufficiency and deficiency, suggesting complicated interactions with unknown factors for

EFICIÊNCIA AGRONÔMICA DOS RIZÓBIOS SEMIA 6156, F 3 (4, F 2 (1, F2 - 2B, CPAC-B10 EM FEIJÃO DE PORCO

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Thiago Santos de Paula Silva

2015-07-01

Full Text Available O objetivo foi validar e recomendar bactérias fixadoras de nitrogênio usadas em inoculantes comerciais na leguminosa Canavalia ensiformis. O trabalho foi conduzido durante os meses de novembro de 2013 a fevereiro 2014. O delineamento experimental foi o de blocos ao acaso com quatro repetições e com unidade experimental de 24 m2, o plantio realizado no espaçamento de 0,5 m entre sulcos, densidade de 10 sementes por metro linear, As estirpes de rizóbio avaliadas foram: SEMIA 6156, F 3 (4, F 2 (1, F2 - 2B, CPAC-B10. A primeira avaliação foi realizada aos 30 dias após a semeadura (DAS, para número e massa de nódulos frescos e secos, massa seca da parte aérea e raízes. A segunda avaliação foi realizada quando 50% das plantas estavam em florescimento, quantificando-se a massa seca das folhas e caules, massa seca total da parte aérea e análise total de macronutrientes em folhas e caule. A estirpe F 2 (1 pode realizar efetiva simbiose com as plantas de feijão de porco, promovendo ganhos no acúmulo de massa seca de parte aérea das plantas, sendo assim considerada agronomicamente eficiente e recomendada para uso em inoculantes comerciais.

JAK2 V617F-dependent upregulation of PU.1 expression in the peripheral blood of myeloproliferative neoplasm patients.

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Tamotsu Irino

Full Text Available Myeloproliferative neoplasms (MPN are multiple disease entities characterized by clonal expansion of one or more of the myeloid lineages (i.e. granulocytic, erythroid, megakaryocytic and mast cell. JAK2 mutations, such as the common V617F substitution and the less common exon 12 mutations, are frequently detected in such tumor cells and have been incorporated into the diagnostic criteria published by the World Health Organization since 2008. However, the mechanism by which these mutations contribute to MPN development is poorly understood. We examined gene expression profiles of MPN patients focusing on genes in the JAK-STAT signaling pathway using low-density real-time PCR arrays. We identified the following 2 upregulated genes in MPN patients: a known target of the JAK-STAT axis, SOCS3, and a potentially novel target, SPI1, encoding PU.1. Induction of PU.1 expression by JAK2 V617F in JAK2-wildtype K562 cells and its downregulation by JAK2 siRNA transfection in JAK2 V617F-positive HEL cells supported this possibility. We also found that the ABL1 kinase inhibitor imatinib was very effective in suppressing PU.1 expression in BCR-ABL1-positive K562 cells but not in HEL cells. This suggests that PU.1 expression is regulated by both JAK2 and ABL1. The contribution of the two kinases in driving PU.1 expression was dominant for JAK2 and ABL1 in HEL and K562 cells, respectively. Therefore, PU.1 may be a common transcription factor upregulated in MPN. PU.1 is a transcription factor required for myeloid differentiation and is implicated in erythroid leukemia. Therefore, expression of PU.1 downstream of activated JAK2 may explain why JAK2 mutations are frequently observed in MPN patients.

Micro-RNA-128 (miRNA-128) down-regulation in glioblastoma targets ARP5 (ANGPTL6), Bmi-1 and E2F-3a, key regulators of brain cell proliferation.

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Cui, J G; Zhao, Y; Sethi, P; Li, Y Y; Mahta, A; Culicchia, F; Lukiw, W J

2010-07-01

High density micro-RNA (miRNA) arrays, fluorescent-reporter miRNA assay and Northern miRNA dot-blot analysis show that a brain-enriched miRNA-128 is significantly down-regulated in glioblastoma multiforme (GBM) and in GBM cell lines when compared to age-matched controls. The down-regulation of miRNA-128 was found to inversely correlate with WHO tumor grade. Three bioinformatics-verified miRNA-128 targets, angiopoietin-related growth factor protein 5 (ARP5; ANGPTL6), a transcription suppressor that promotes stem cell renewal and inhibits the expression of known tumor suppressor genes involved in senescence and differentiation, Bmi-1, and a transcription factor critical for the control of cell-cycle progression, E2F-3a, were found to be up-regulated. Addition of exogenous miRNA-128 to CRL-1690 and CRL-2610 GBM cell lines (a) restored 'homeostatic' ARP5 (ANGPTL6), Bmi-1 and E2F-3a expression, and (b) significantly decreased the proliferation of CRL-1690 and CRL-2610 cell lines. Our data suggests that down-regulation of miRNA-128 may contribute to glioma and GBM, in part, by coordinately up-regulating ARP5 (ANGPTL6), Bmi-1 and E2F-3a, resulting in the proliferation of undifferentiated GBM cells.

Transcriptome analysis uncovers Arabidopsis F-BOX STRESS INDUCED 1 as a regulator of jasmonic acid and abscisic acid stress gene expression.

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Gonzalez, Lauren E; Keller, Kristen; Chan, Karen X; Gessel, Megan M; Thines, Bryan C

2017-07-17

The ubiquitin 26S proteasome system (UPS) selectively degrades cellular proteins, which results in physiological changes to eukaryotic cells. F-box proteins are substrate adaptors within the UPS and are responsible for the diversity of potential protein targets. Plant genomes are enriched in F-box genes, but the vast majority of these have unknown roles. This work investigated the Arabidopsis F-box gene F-BOX STRESS INDUCED 1 (FBS1) for its effects on gene expression in order elucidate its previously unknown biological function. Using publically available Affymetrix ATH1 microarray data, we show that FBS1 is significantly co-expressed in abiotic stresses with other well-characterized stress response genes, including important stress-related transcriptional regulators. This gene suite is most highly expressed in roots under cold and salt stresses. Transcriptome analysis of fbs1-1 knock-out plants grown at a chilling temperature shows that hundreds of genes require FBS1 for appropriate expression, and that these genes are enriched in those having roles in both abiotic and biotic stress responses. Based on both this genome-wide expression data set and quantitative real-time PCR (qPCR) analysis, it is apparent that FBS1 is required for elevated expression of many jasmonic acid (JA) genes that have established roles in combatting environmental stresses, and that it also controls a subset of JA biosynthesis genes. FBS1 also significantly impacts abscisic acid (ABA) regulated genes, but this interaction is more complex, as FBS1 has both positive and negative effects on ABA-inducible and ABA-repressible gene modules. One noteworthy effect of FBS1 on ABA-related stress processes, however, is the restraint it imposes on the expression of multiple class I LIPID TRANSFER PROTEIN (LTP) gene family members that have demonstrated protective effects in water deficit-related stresses. FBS1 impacts plant stress responses by regulating hundreds of genes that respond to the plant

ERK1/2 mediates glucose-regulated POMC gene expression in hypothalamic neurons.

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Zhang, Juan; Zhou, Yunting; Chen, Cheng; Yu, Feiyuan; Wang, Yun; Gu, Jiang; Ma, Lian; Ho, Guyu

2015-04-01

Hypothalamic glucose-sensing neurons regulate the expression of genes encoding feeding-related neuropetides POMC, AgRP, and NPY - the key components governing metabolic homeostasis. AMP-activated protein kinase (AMPK) is postulated to be the molecular mediator relaying glucose signals to regulate the expression of these neuropeptides. Whether other signaling mediator(s) plays a role is not clear. In this study, we investigated the role of ERK1/2 using primary hypothalamic neurons as the model system. The primary neurons were differentiated from hypothalamic progenitor cells. The differentiated neurons possessed the characteristic neuronal cell morphology and expressed neuronal post-mitotic markers as well as leptin-regulated orexigenic POMC and anorexigenic AgRP/NPY genes. Treatment of cells with glucose dose-dependently increased POMC and decreased AgRP/NPY expression with a concurrent suppression of AMPK phosphorylation. In addition, glucose treatment dose-dependently increased the ERK1/2 phosphorylation. Blockade of ERK1/2 activity with its specific inhibitor PD98059 partially (approximately 50%) abolished glucose-induced POMC expression, but had little effect on AgRP/NPY expression. Conversely, blockade of AMPK activity with its specific inhibitor produced a partial (approximately 50%) reversion of low-glucose-suppressed POMC expression, but almost completely blunted the low-glucose-induced AgRP/NPY expression. The results indicate that ERK1/2 mediated POMC but not AgRP/NPY expression. Confirming the in vitro findings, i.c.v. administration of PD98059 in rats similarly attenuated glucose-induced POMC expression in the hypothalamus, but again had little effect on AgRP/NPY expression. The results are indicative of a novel role of ERK1/2 in glucose-regulated POMC expression and offer new mechanistic insights into hypothalamic glucose sensing. © 2015 Society for Endocrinology.

A novel mechanism of E2F1 regulation via nucleocytoplasmic shuttling: determinants of nuclear import and export.

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Ivanova, Iordanka A; Vespa, Alisa; Dagnino, Lina

2007-09-01

E2F1 is a transcription factor central for cell survival, proliferation, and repair following genomic insult. Depending on the cell type and conditions, E2F1 can induce apoptosis in transformed cells, behaving as a tumour suppressor, or impart growth advantages favouring tumour formation. The pleiotropic functions of E2F1 are a likely consequence of its ability to transcriptionally control a wide variety of target genes, and require tight regulation of its activity at multiple levels. Although sequestration of proteins to particular cellular compartments is a well-established regulatory mechanism, virtually nothing is known about its contribution to modulation of E2F1 target gene expression. We have examined the subcellular trafficking of E2F1 and, contrary to the widely held notion that this factor is constitutively nuclear, we now demonstrate that it is subjected to continuous nucleocytoplasmic shuttling. We have also defined two nuclear localization domains and a nuclear export region, which mediates CRM1-dependent transit out of the nucleus. The predominant subcellular location of E2F1 is likely determined by the balance between the activity of nuclear import and export domains, and can be modulated by differentiation stimuli in epidermal cells. Thus, we have identified a hitherto unrecognized mechanism to control E2F1 function through modulation of its subcellular localization.

E2F-5, a new E2F family member that interacts with p130 in vivo

NARCIS (Netherlands)

Hijmans, E.M.; Voorhoeve, P.M.; Beijersbergen, R.L.; Veer, L.J. van 't; Bernards, R.A.

1995-01-01

E2F DNA binding sites are found in a number of genes whose expression is tightly regulated during the cell cycle. The activity of E2F transcription factors is regulated by association with specific repressor molecules that can bind and inhibit the E2F transactivation domain. For E2F-1, E2F-2, and

The CYP2E1 inhibitor DDC up-regulates MMP-1 expression in hepatic stellate cells via an ERK1/2- and Akt-dependent mechanism.

Science.gov (United States)

Liu, Tianhui; Wang, Ping; Cong, Min; Xu, Youqing; Jia, Jidong; You, Hong

2013-06-05

DDC (diethyldithiocarbamate) could block collagen synthesis in HSC (hepatic stellate cells) through the inhibition of ROS (reactive oxygen species) derived from hepatocyte CYP2E1 (cytochrome P450 2E1). However, the effect of DDC on MMP-1 (matrix metalloproteinase-1), which is the main collagen degrading matrix metalloproteinase, has not been reported. In co-culture experiments, we found that DDC significantly enhanced MMP-1 expression in human HSC (LX-2) that were cultured with hepatocyte C3A cells either expressing or not expressing CYP2E1. The levels of both proenzyme and active MMP-1 enzyme were up-regulated in LX-2 cells, accompanied by elevated enzyme activity of MMP-1 and decreased collagen I, in both LX-2 cells and the culture medium. H2O2 treatment abrogated DDC-induced MMP-1 up-regulation and collagen I decrease, while catalase treatment slightly up-regulated MMP-1 expression. These data suggested that the decrease in ROS by DDC was partially responsible for the MMP-1 up-regulation. ERK1/2 (extracellular signal-regulated kinase 1/2), Akt (protein kinase B) and p38 were significantly activated by DDC. The ERK1/2 inhibitor (U0126) and Akt inhibitor (T3830) abrogated the DDC-induced MMP-1 up-regulation. In addition, a p38 inhibitor (SB203580) improved MMP-1 up-regulation through the stimulation of ERK1/2. Our data indicate that DDC significantly up-regulates the expression of MMP-1 in LX-2 cells which results in greater MMP-1 enzyme activity and decreased collagen I. The enhancement of MMP-1 expression by DDC was associated with H2O2 inhibition and coordinated regulation by the ERK1/2 and Akt pathways. These data provide some new insights into treatment strategies for hepatic fibrosis.

Synergistic cooperation of MDM2 and E2F1 contributes to TAp73 transcriptional activity

Energy Technology Data Exchange (ETDEWEB)

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

2014-07-04

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

Synergistic cooperation of MDM2 and E2F1 contributes to TAp73 transcriptional activity

International Nuclear Information System (INIS)

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

2014-01-01

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

The RB/E2F pathway and regulation of RNA processing

Energy Technology Data Exchange (ETDEWEB)

Ahlander, Joseph [Department of Molecular and Cellular Biology, 1007 East Lowell Street, University of Arizona, Tucson, AZ 85721 (United States); Bosco, Giovanni, E-mail: gbosco@email.arizona.edu [Department of Molecular and Cellular Biology, 1007 East Lowell Street, University of Arizona, Tucson, AZ 85721 (United States)

2009-07-03

The retinoblastoma tumor suppressor protein (RB) is inactivated in a majority of cancers. RB restricts cell proliferation by inhibiting the E2F family of transcription factors. The current model for RB/E2F function describes its role in regulating transcription at gene promoters. Whether the RB or E2F proteins might play a role in gene expression beyond transcription initiation is not well known. This review describes evidence that points to a novel role for the RB/E2F network in the regulation of RNA processing, and we propose a model as a framework for future research. The elucidation of a novel role of RB in RNA processing will have a profound impact on our understanding of the role of this tumor suppressor family in cell and developmental biology.

Long non-coding RNA TUG1 contributes to tumorigenesis of human osteosarcoma by sponging miR-9-5p and regulating POU2F1 expression.

Science.gov (United States)

Xie, Chu-Hai; Cao, Yan-Ming; Huang, Yan; Shi, Qun-Wei; Guo, Jian-Hong; Fan, Zi-Wen; Li, Ju-Gen; Chen, Bin-Wei; Wu, Bo-Yi

2016-11-01

Recent studies have shown that long non-coding RNAs (lncRNAs) have critical roles in tumorigenesis, including osteosarcoma. The lncRNA taurine-upregulated gene 1 (TUG1) was reported to be involved in the progression of osteosarcoma. Here, we investigated the role of TUG1 in osteosarcoma cells and the underlying mechanism. TUG1 expression was measured in osteosarcoma cell lines and human normal osteoblast cells by quantitative real-time PCR (qRT-PCR). The effects of TUG1 on osteosarcoma cells were studied by RNA interference in vitro and in vivo. The mechanism of competing endogenous RNA (ceRNA) was determined using bioinformatic analysis and luciferase assays. Our data showed that TUG1 knockdown inhibited cell proliferation and colony formation, and induced G0/G1 cell cycle arrest and apoptosis in vitro, and suppressed tumor growth in vivo. Besides, we found that TUG1 acted as an endogenous sponge to directly bind to miR-9-5p and downregulated miR-9-5p expression. Moreover, TUG1 overturned the effect of miR-9-5p on the proliferation, colony formation, cell cycle arrest, and apoptosis in osteosarcoma cells, which involved the derepression of POU class 2 homeobox 1 (POU2F1) expression. In conclusion, our study elucidated a novel TUG1/miR-9-5p/POU2F1 pathway, in which TUG1 acted as a ceRNA by sponging miR-9-5p, leading to downregulation of POU2F1 and facilitating the tumorigenesis of osteosarcoma. These findings may contribute to the lncRNA-targeted therapy for human osteosarcoma.

Pou1f1, the key transcription factor related to somatic growth in tilapia (Orechromis niloticus), is regulated by two independent post-transcriptional regulation mechanisms.

Science.gov (United States)

Wang, Dongfang; Qin, Jingkai; Jia, Jirong; Yan, Peipei; Li, Wensheng

2017-01-29

This study aims to determine the post-transcriptional regulation mechanism of the transcription factor pou1f1 (pou class 1 homeobox 1), which is the key gene for pituitary development, somatic growth in vertebrates, and transcription of several hormone genes in teleost fish. MicroRNA miR-223-3p was identified as a bona fide target of pou1f; overexpression of miR-223-3p in primary pituitary cells led to the down-regulation of pou1f1 and downstream genes, and inhibition of miR-223-3p led to the up-regulation of pou1f1 in Nile tilapia dispersed primary pituitary cells. An adenylate-uridylate-rich element (AU-Rich element) was found in the 3'UTR of pou1f1 mRNA, and deletion of the AU-Rich element led to slower mRNA decay and therefore more protein output. A potential mutual relationship between miR-223-3p and the AU-rich element was also investigated, and the results demonstrated that with or without the AU-Rich element, miR-223-3p induced the up-regulation of a reporter system under serum starvation conditions, indicating that miR-223-3p and the AU-Rich element function independent of each other. This study is the first to investigate the post-transcriptional mechanism of pou1f1, which revealed that miR-223-3p down-regulated pou1f1 and downstream gene expressions, and the AU-Rich element led to rapid decay of pou1f1 mRNA. MicroRNA miR-223-3p and the AU-Rich element co-regulated the post-transcriptional expression of pou1f1 independently in Nile tilapia, demonstrating that pou1f1 is under the control of a dual post-transcription regulation mechanism. Copyright © 2016 Elsevier Inc. All rights reserved.

CYP79F1 and CYP79F2 have distinct functions in the biosynthesis of aliphatic glucosinolates in Arabidopsis.

Science.gov (United States)

Chen, Sixue; Glawischnig, Erich; Jørgensen, Kirsten; Naur, Peter; Jørgensen, Bodil; Olsen, Carl-Erik; Hansen, Carsten H; Rasmussen, Hasse; Pickett, John A; Halkier, Barbara A

2003-03-01

Cytochromes P450 of the CYP79 family catalyze the conversion of amino acids to oximes in the biosynthesis of glucosinolates, a group of natural plant products known to be involved in plant defense and as a source of flavor compounds, cancer-preventing agents and bioherbicides. We report a detailed biochemical analysis of the substrate specificity and kinetics of CYP79F1 and CYP79F2, two cytochromes P450 involved in the biosynthesis of aliphatic glucosinolates in Arabidopsis thaliana. Using recombinant CYP79F1 and CYP79F2 expressed in Escherichia coli and Saccharomyces cerevisiae, respectively, we show that CYP79F1 metabolizes mono- to hexahomomethionine, resulting in both short- and long-chain aliphatic glucosinolates. In contrast, CYP79F2 exclusively metabolizes long-chain elongated penta- and hexahomomethionines. CYP79F1 and CYP79F2 are spatially and developmentally regulated, with different gene expression patterns. CYP79F2 is highly expressed in hypocotyl and roots, whereas CYP79F1 is strongly expressed in cotyledons, rosette leaves, stems, and siliques. A transposon-tagged CYP79F1 knockout mutant completely lacks short-chain aliphatic glucosinolates, but has an increased level of long-chain aliphatic glucosinolates, especially in leaves and seeds. The level of long-chain aliphatic glucosinolates in a transposon-tagged CYP79F2 knockout mutant is substantially reduced, whereas the level of short-chain aliphatic glucosinolates is not affected. Biochemical characterization of CYP79F1 and CYP79F2, and gene expression analysis, combined with glucosinolate profiling of knockout mutants demonstrate the functional role of these enzymes. This provides valuable insights into the metabolic network leading to the biosynthesis of aliphatic glucosinolates, and into metabolic engineering of altered aliphatic glucosinolate profiles to improve nutritional value and pest resistance.

miR-24 inhibits cell proliferation by suppressing expression of E2F2, MYC and other cell cycle regulatory genes by binding to “seedless” 3′UTR microRNA recognition elements

Science.gov (United States)

Lal, Ashish; Navarro, Francisco; Maher, Christopher; Maliszewski, Laura E.; Yan, Nan; O'Day, Elizabeth; Chowdhury, Dipanjan; Dykxhoorn, Derek M.; Tsai, Perry; Hofman, Oliver; Becker, Kevin G.; Gorospe, Myriam; Hide, Winston; Lieberman, Judy

2009-01-01

Summary miR-24, up-regulated during terminal differentiation of multiple lineages, inhibits cell cycle progression. Antagonizing miR-24 restores post-mitotic cell proliferation and enhances fibroblast proliferation, while over-expressing miR-24 increases the G1 compartment. The 248 mRNAs down-regulated upon miR-24 over-expression are highly enriched for DNA repair and cell cycle regulatory genes that form a direct interaction network with prominent nodes at genes that enhance (MYC, E2F2, CCNB1, CDC2) or inhibit (p27Kip1, VHL) cell cycle progression. miR-24 directly regulates MYC and E2F2 and some genes they transactivate. Enhanced proliferation from antagonizing miR-24 is abrogated by knocking down E2F2, but not MYC, and cell proliferation, inhibited by miR-24 over-expression, is rescued by miR-24-insensitive E2F2. Therefore, E2F2 is a critical miR-24 target. The E2F2 3′UTR lacks a predicted miR-24 recognition element. In fact, miR-24 regulates expression of E2F2, MYC, AURKB, CCNA2, CDC2, CDK4 and FEN1 by recognizing seedless, but highly complementary, sequences. PMID:19748357

Epigenetic involvement of Alien/ESET complex in thyroid hormone-mediated repression of E2F1 gene expression and cell proliferation

International Nuclear Information System (INIS)

Hong, Wei; Li, Jinru; Wang, Bo; Chen, Linfeng; Niu, Wenyan; Yao, Zhi; Baniahmad, Aria

2011-01-01

Highlights: ► Corepressor Alien interacts with histone methyltransferase ESET in vivo. ► Alien/ESET complex is recruited to nTRE of T3-responsive gene by liganded TRβ1. ► ESET-mediated H3K9 methylation is required for liganded TRβ1-repressed transcription. ► ESET is involved in T3-repressed G1/S phase transition and proliferation. -- Abstract: The ligand-bound thyroid hormone receptor (TR) is known to repress via a negative TRE (nTRE) the expression of E2F1, a key transcription factor that controls the G1/S phase transition. Alien has been identified as a novel interacting factor of E2F1 and acts as a corepressor of E2F1. The detailed molecular mechanism by which Alien inhibits E2F1 gene expression remains unclear. Here, we report that the histone H3 lysine 9 (H3K9) methyltransferase (HMT) ESET is an integral component of the corepressor Alien complex and the Alien/ESET complex is recruited to both sites, the E2F1 and the nTRE site of the E2F1 gene while the recruitment to the negative thyroid hormone response element (nTRE) is induced by the ligand-bound TRβ1 within the E2F1 gene promoter. We show that, overexpression of ESET promotes, whereas knockdown of ESET releases, the inhibition of TRβ1-regulated gene transcription upon T3 stimulation; and H3K9 methylation is required for TRβ1-repressed transcription. Furthermore, depletion of ESET impairs thyroid hormone-repressed proliferation as well as the G1/S transition of the cell cycle. Taken together, our data indicate that ESET is involved in TRβ1-mediated transcription repression and provide a molecular basis of thyroid hormone-induced repression of proliferation.

MicroRNA-17-92 Regulates the Transcription Factor E2F3b during Myogenesis In Vitro and In Vivo

Directory of Open Access Journals (Sweden)

Zhixiong Tang

2017-03-01

Full Text Available Myogenic differentiation, which occurs during muscle development, is a highly ordered process that can be regulated by E2F transcription factors. Available data show that E2F3b, but not E2F3a, is upregulated and required for myogenic differentiation. However, the regulation of E2F3b expression in myogenic differentiation is not well understood. To investigate whether E2Fb expression is controlled by miRNAs, we used bioinformatics to combine the database of microRNAs downregulated during myogenesis and those predicted to target E2F3. This identified miR-17 and miR-20a as miRNAs potentially involved in E2F3 regulation. We found that miR-17-92 controls the expression of E2F3b in C2C12 cells during myogenic differentiation. Moreover, we confirmed that miR-20a regulates the expression of E2F3b proteins in vivo using a muscle regeneration model.

Fibroblast growth factor-2 up-regulates the expression of nestin through the Ras–Raf–ERK–Sp1 signaling axis in C6 glioma cells

International Nuclear Information System (INIS)

Chang, Kai-Wei; Huang, Yuan-Li; Wong, Zong-Ruei; Su, Peng-Han; Huang, Bu-Miin; Ju, Tsai-Kai; Yang, Hsi-Yuan

2013-01-01

Highlights: •Nestin expression in C6 glioma cells is induced by FGF-2. •Nestin expression is induced by FGF-2 via de novo RNA and protein synthesis. •The FGFR inhibitor SU5402 blocks the FGF-2-induced nestin expression. •The mRNA of FGFR1 and 3 are detected in C6 glioma cells. •Ras–Raf–ERK–Sp1 signaling pathway is responsibe for FGF-2-induced nestin expression. -- Abstract: Nestin is a 240-kDa intermediate filament protein expressed mainly in neural and myogenic stem cells. Although a substantial number of studies have focused on the expression of nestin during development of the central nervous system, little is known about the factors that induce and regulate its expression. Fibroblast growth factor-2 (FGF-2) is an effective mitogen and stimulates the proliferation and differentiation of a subset of nestin-expressing cells, including neural progenitor cells, glial precursor cells, and smooth muscle cells. To assess whether FGF-2 is a potent factor that induces the expression of nestin, C6 glioma cells were used. The results showed that nestin expression was up-regulated by FGF-2 via de novo RNA and protein synthesis. Our RT-PCR results showed that C6 glioma cells express FGFR1/3, and FGFRs is required for FGF-2-induced nestin expression. Further signaling analysis also revealed that FGF-2-induced nestin expression is mediated through FGFR–MAPK–ERK signaling axis and the transcriptional factor Sp1. These findings provide new insight into the regulation of nestin in glial system and enable the further studies on the function of nestin in glial cells

Fibroblast growth factor-2 up-regulates the expression of nestin through the Ras–Raf–ERK–Sp1 signaling axis in C6 glioma cells

Energy Technology Data Exchange (ETDEWEB)

Chang, Kai-Wei [Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan (China); Huang, Yuan-Li [Department of Biotechnology, College of Health Science, Asia University, Taichung 413, Taiwan (China); Wong, Zong-Ruei; Su, Peng-Han [Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan (China); Huang, Bu-Miin [Department of Cell Biology and Anatomy, National Cheng-Kung University, Tainan 701, Taiwan (China); Ju, Tsai-Kai [Instrumentation Center, National Taiwan University, Taipei 106, Taiwan (China); Technology Commons, College of Life Science, National Taiwan University, Taipei 106, Taiwan (China); Yang, Hsi-Yuan, E-mail: hyhy@ntu.edu.tw [Institute of Molecular and Cellular Biology, National Taiwan University, Taipei 106, Taiwan (China)

2013-05-17

Highlights: •Nestin expression in C6 glioma cells is induced by FGF-2. •Nestin expression is induced by FGF-2 via de novo RNA and protein synthesis. •The FGFR inhibitor SU5402 blocks the FGF-2-induced nestin expression. •The mRNA of FGFR1 and 3 are detected in C6 glioma cells. •Ras–Raf–ERK–Sp1 signaling pathway is responsibe for FGF-2-induced nestin expression. -- Abstract: Nestin is a 240-kDa intermediate filament protein expressed mainly in neural and myogenic stem cells. Although a substantial number of studies have focused on the expression of nestin during development of the central nervous system, little is known about the factors that induce and regulate its expression. Fibroblast growth factor-2 (FGF-2) is an effective mitogen and stimulates the proliferation and differentiation of a subset of nestin-expressing cells, including neural progenitor cells, glial precursor cells, and smooth muscle cells. To assess whether FGF-2 is a potent factor that induces the expression of nestin, C6 glioma cells were used. The results showed that nestin expression was up-regulated by FGF-2 via de novo RNA and protein synthesis. Our RT-PCR results showed that C6 glioma cells express FGFR1/3, and FGFRs is required for FGF-2-induced nestin expression. Further signaling analysis also revealed that FGF-2-induced nestin expression is mediated through FGFR–MAPK–ERK signaling axis and the transcriptional factor Sp1. These findings provide new insight into the regulation of nestin in glial system and enable the further studies on the function of nestin in glial cells.

A Novel Regulatory Mechanism of Smooth Muscle α-Actin Expression by NRG-1/circACTA2/miR-548f-5p Axis.

Science.gov (United States)

Sun, Yan; Yang, Zhan; Zheng, Bin; Zhang, Xin-Hua; Zhang, Man-Li; Zhao, Xue-Shan; Zhao, Hong-Ye; Suzuki, Toru; Wen, Jin-Kun

2017-09-01

Neuregulin-1 (NRG-1) includes an extracellular epidermal growth factor-like domain and an intracellular domain (NRG-1-ICD). In response to transforming growth factor-β1, its cleavage by proteolytic enzymes releases a bioactive fragment, which suppresses the vascular smooth muscle cell (VSMC) proliferation by activating ErbB (erythroblastic leukemia viral oncogene homolog) receptor. However, NRG-1-ICD function in VSMCs remains unknown. Here, we characterize the function of NRG-1-ICD and underlying mechanisms in VSMCs. Immunofluorescence staining, Western blotting, and quantitative real-time polymerase chain reaction showed that NRG-1 was expressed in rat, mouse, and human VSMCs and was upregulated and cleaved in response to transforming growth factor-β1. In the cytoplasm of HASMCs (human aortic smooth muscle cells), the NRG-1-ICD participated in filamentous actin formation by interacting with α-SMA (smooth muscle α-actin). In the nucleus, the Nrg-1-ICD induced circular ACTA2 (alpha-actin-2; circACTA2) formation by recruitment of the zinc-finger transcription factor IKZF1 (IKAROS family zinc finger 1) to the first intron of α-SMA gene. We further confirmed that circACTA2, acting as a sponge binding microRNA (miR)-548f-5p, interacted with miR-548f-5p targeting 3' untranslated region of α-SMA mRNA, which in turn relieves miR-548f-5p repression of the α-SMA expression and thus upregulates α-SMA expression, thereby facilitating stress fiber formation and cell contraction in HASMCs. Accordingly, in vivo studies demonstrated that the localization of the interaction of circACTA2 with miR-548f-5p is significantly decreased in human intimal hyperplastic arteries compared with normal arteries, implicating that dysregulation of circACTA2 and miR-548f-5p expression is involved in intimal hyperplasia. These results suggest that circACTA2 mediates NRG-1-ICD regulation of α-SMA expression in HASMCs via the NRG-1-ICD/circACTA2/miR-548f-5p axis. Our data provide a molecular

Regulation of cell proliferation by the E2F transcription factors

DEFF Research Database (Denmark)

Helin, K

1998-01-01

Experimental data generated in the past year have further emphasized the essential role for the E2F transcription factors in the regulation of cell proliferation. Genetic studies have shown that E2F activity is required for normal development in fruitflies, and the generation of E2F-1(-/-) mice h......Fs in the proteasomes. Novel target genes for the E2F transcription factors have been identified that link the E2Fs directly to the initiation of DNA replication.......Experimental data generated in the past year have further emphasized the essential role for the E2F transcription factors in the regulation of cell proliferation. Genetic studies have shown that E2F activity is required for normal development in fruitflies, and the generation of E2F-1(-/-) mice has...... demonstrated that individual members of the E2F transcription factor family are likely to have distinct roles in mammalian development and homeostasis. Additional mechanisms regulating the activity of the E2F transcription factors have been reported, including subcellular localization and proteolysis of the E2...

Herpes simplex virus thymidine kinase imaging in mice with (1-(2'-deoxy-2'-[{sup 18}F]fluoro-1-{beta}-D-arabinofuranosyl)-5-iodouracil) and metabolite (1-(2'-deoxy-2'-[{sup 18}F]fluoro-1-{beta}-D-arabinofuranosyl)-5-uracil)

Energy Technology Data Exchange (ETDEWEB)

Nimmagadda, Sridhar; Lawhorn-Crews, Jawana M.; Shields, Anthony F. [Wayne State University, Karmanos Cancer Institute, Detroit, MI (United States); Wayne State University, Department of Medicine, Detroit, MI (United States); Mangner, Thomas J. [Wayne State University, Karmanos Cancer Institute, Detroit, MI (United States); Wayne State University, Department of Radiology, Detroit, MI (United States); Haberkorn, Uwe [University of Heidelberg, Department of Nuclear Medicine, Heidelberg (Germany)

2009-12-15

FIAU, (1-(2{sup '}-deoxy-2{sup '}-fluoro-1-{beta}-D-arabinofuranosyl)-5-iodouracil) has been used as a substrate for herpes simplex virus thymidine kinases (HSV-TK and HSV-tk, for protein and gene expression, respectively) and other bacterial and viral thymidine kinases for noninvasive imaging applications. Previous studies have reported the formation of a de-iodinated metabolite of {sup 18}F-FIAU. This study reports the dynamic tumor uptake, biodistribution, and metabolite contribution to the activity of {sup 18}F-FIAU seen in HSV-tk gene expressing tumors and compares the distribution properties with its de-iodinated metabolite {sup 18}F-FAU. CD-1 nu/nu mice with subcutaneous MH3924A and MH3924A-stb-tk+ xenografts on opposite flanks were used for the biodistribution and imaging studies. Mice were injected IV with either {sup 18}F-FIAU or {sup 18}F-FAU. Mice underwent dynamic imaging with each tracer for 65 min followed by additional static imaging up to 150 min post-injection for some animals. Animals were sacrificed at 60 or 150 min post-injection. Samples of blood and tissue were collected for biodistribution and metabolite analysis. Regions of interest were drawn over the images obtained from both tumors to calculate the time-activity curves. Biodistribution and imaging studies showed the highest uptake of {sup 18}F-FIAU in the MH3924A-stb-tk+ tumors. Dynamic imaging studies revealed a continuous accumulation of {sup 18}F-FIAU in HSV-TK expressing tumors over 60 min. The mean biodistribution values (SUV {+-} SE) for MH3924A-stb-tk+ were 2.07 {+-} 0.40 and 6.15 {+-} 1.58 and that of MH3924A tumors were 0.19 {+-} 0.07 and 0.47 {+-} 0.06 at 60 and 150 min, respectively. In {sup 18}F-FIAU injected mice, at 60 min nearly 63% of blood activity was present as its metabolite {sup 18}F-FAU. Imaging and biodistribution studies with {sup 18}F-FAU demonstrated no specific accumulation in MH3924A-stb-tk+ tumors and SUVs for both the tumors were similar to those

Progesterone and 17β-estradiol regulate expression of nesfatin-1/NUCB2 in mouse pituitary gland.

Science.gov (United States)

Chung, Yiwa; Kim, Jinhee; Im, Eunji; Kim, Heejeong; Yang, Hyunwon

2015-01-01

Nesfatin-1 was first shown to be involved in the control of appetite and energy metabolism in the hypothalamus. Many recent reports have shown nesfatin-1 expression in various tissues including the pituitary gland, but its expression and regulation mechanisms in the pituitary gland are unclear. Therefore, first, we investigated the mRNA and protein expression of nesfatin-1 in the pituitary using qRT-PCR and Western blotting, respectively. Expression of NUCB2 mRNA and nesfatin-1 protein was higher in the pituitary gland than in other organs, and nesfatin-1 protein was localized in many cells in the anterior pituitary gland. Next, we investigated whether NUCB2 mRNA expression in the pituitary gland was regulated by sex steroid hormones secreted by the ovary. Mice were ovariectomized and injected with progesterone (P4) and 17β-estradiol (E2). The expression of NUCB2 in the pituitary gland was dramatically decreased after ovariectomy and increased with injection of P4 and E2, respectively. The in vitro experiment to elucidate the direct effect of P4 and E2 on NUCB2 mRNA expression showed NUCB2 mRNA expression was significantly increased with E2 and decreased with P4 alone and P4 plus E2 in cultured pituitary tissue. The present study demonstrated that nesfatin-1/NUCB2 was highly expressed in the mouse pituitary and was regulated by P4 and E2. These data suggest that reproductive-endocrine regulation through hypothalamus-pituitary-ovary axis may contribute to nesfatin-1/NUCB2 expression in the pituitary gland. Copyright © 2014 Elsevier Inc. All rights reserved.

Epigenetic involvement of Alien/ESET complex in thyroid hormone-mediated repression of E2F1 gene expression and cell proliferation

Energy Technology Data Exchange (ETDEWEB)

Hong, Wei, E-mail: hongwei@tijmu.edu.cn [Department of Immunology, Tianjin Medical University, 300070 Tianjin (China); College of Basic Medicine, Tianjin Medical University, 300070 Tianjin (China); Li, Jinru; Wang, Bo [College of Basic Medicine, Tianjin Medical University, 300070 Tianjin (China); Chen, Linfeng [Department of Medical Oncology, Harvard Medical School, Dana Farber Cancer Institute, Boston, 02115 MA (United States); Niu, Wenyan; Yao, Zhi [Department of Immunology, Tianjin Medical University, 300070 Tianjin (China); Baniahmad, Aria, E-mail: aban@mti.uni-jena.de [Institute for Human Genetics, Jena University Hospital, 07740 Jena (Germany)

2011-12-02

Highlights: Black-Right-Pointing-Pointer Corepressor Alien interacts with histone methyltransferase ESET in vivo. Black-Right-Pointing-Pointer Alien/ESET complex is recruited to nTRE of T3-responsive gene by liganded TR{beta}1. Black-Right-Pointing-Pointer ESET-mediated H3K9 methylation is required for liganded TR{beta}1-repressed transcription. Black-Right-Pointing-Pointer ESET is involved in T3-repressed G1/S phase transition and proliferation. -- Abstract: The ligand-bound thyroid hormone receptor (TR) is known to repress via a negative TRE (nTRE) the expression of E2F1, a key transcription factor that controls the G1/S phase transition. Alien has been identified as a novel interacting factor of E2F1 and acts as a corepressor of E2F1. The detailed molecular mechanism by which Alien inhibits E2F1 gene expression remains unclear. Here, we report that the histone H3 lysine 9 (H3K9) methyltransferase (HMT) ESET is an integral component of the corepressor Alien complex and the Alien/ESET complex is recruited to both sites, the E2F1 and the nTRE site of the E2F1 gene while the recruitment to the negative thyroid hormone response element (nTRE) is induced by the ligand-bound TR{beta}1 within the E2F1 gene promoter. We show that, overexpression of ESET promotes, whereas knockdown of ESET releases, the inhibition of TR{beta}1-regulated gene transcription upon T3 stimulation; and H3K9 methylation is required for TR{beta}1-repressed transcription. Furthermore, depletion of ESET impairs thyroid hormone-repressed proliferation as well as the G1/S transition of the cell cycle. Taken together, our data indicate that ESET is involved in TR{beta}1-mediated transcription repression and provide a molecular basis of thyroid hormone-induced repression of proliferation.

MiR302 regulates SNAI1 expression to control mesangial cell plasticity

DEFF Research Database (Denmark)

De Chiara, L.; Andrews, D.; Watson, A.

2017-01-01

Cell fate decisions are controlled by the interplay of transcription factors and epigenetic modifiers, which together determine cellular identity. Here we elaborate on the role of miR302 in the regulation of cell plasticity. Overexpression of miR302 effected silencing of the TGFβ type II receptor...... and facilitated plasticity in a manner distinct from pluripotency, characterized by increased expression of Snail. miR302 overexpressing mesangial cells also exhibited enhanced expression of EZH2 coincident with Snail upregulation. esiRNA silencing of each component suggest that Smad3 and EZH2 are part...... of a complex that regulates plasticity and that miR302 regulates EZH2 and Snail independently. Subsequent manipulation of miR302 overexpressing cells demonstrated the potential of using this approach for reprogramming as evidenced by de novo expression of the tight junction components ZO-1 and E...

Transcription factors ETF, E2F, and SP-1 are involved in cytokine-independent proliferation of murine hepatocytes.

Science.gov (United States)

Zellmer, Sebastian; Schmidt-Heck, Wolfgang; Godoy, Patricio; Weng, Honglei; Meyer, Christoph; Lehmann, Thomas; Sparna, Titus; Schormann, Wiebke; Hammad, Seddik; Kreutz, Clemens; Timmer, Jens; von Weizsäcker, Fritz; Thürmann, Petra A; Merfort, Irmgard; Guthke, Reinhard; Dooley, Steven; Hengstler, Jan G; Gebhardt, Rolf

2010-12-01

The cellular basis of liver regeneration has been intensely investigated for many years. However, the mechanisms initiating hepatocyte "plasticity" and priming for proliferation are not yet fully clear. We investigated alterations in gene expression patterns during the first 72 hours of C57BL/6N mouse hepatocyte culture on collagen monolayers (CM), which display a high basal frequency of proliferation in the absence of cytokines. Although many metabolic genes were down-regulated, genes related to mitogen-activated protein kinase (MAPK) signaling and cell cycle were up-regulated. The latter genes showed an overrepresentation of transcription factor binding sites (TFBS) for ETF (TEA domain family member 2), E2F1 (E2F transcription factor 1), and SP-1 (Sp1 transcription factor) (P ETF, E2F1, and SP-1 and displayed increased expression of E2F1. Cultivation of murine hepatocytes on CM primes cells for proliferation through cytokine-independent activation of MAPK signaling. The transcription factors ETF, E2F1, and SP-1 seem to play a pronounced role in mediating proliferation-dependent differential gene expression. Similar events, but on a shorter time-scale, occur very early after liver damage in vivo. Copyright © 2010 American Association for the Study of Liver Diseases.

Larval development of Spodoptera eridania and Spodoptera frugiperda fed on fresh ear of field corn expressing the Bt proteins (Cry1F and Cry1F + Cry1A.105 + Cry2Ab2

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Orcial Ceolin Bortolotto

Full Text Available ABSTRACT: The objective of this study was to evaluate extent of larval period, larval survival (%, food consumption, and pupal biomass of Spodoptera eridania and Spodoptera frugiperda (Lepidoptera: Noctuidae fed on fresh ears of field corn expressing Bt proteins (Cry1F and Cry1F+Cry1A.105+Cry2Ab2. Larvae of Spodoptera spp. survived less than two days when they consumed Bt corncobs and showed 100% mortality. Spodoptera eridania reared on non-Bt corn cobs showed higher larval development (21.6 days than S. frugiperda (18.4 days and lower viability (56.4% and 80.2% for S. eridania and S. frugiperda , respectively. A higher amount of corn grains was consumed by S. eridania (5.4g than by S. frugiperda (3.9g. In summary, this study demonstrated that the toxins Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 expressed in fresh corn cobs contributed to protect ears of corn against S. frugiperda and the non-target pest S. eridania . However, itis important to monitor non-Bt cornfields because of the potential of both species to cause damage to ear sof corn.

Larval development of Spodoptera eridania (Cramer fed on leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 proteins and its non-Bt isoline

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Orcial Ceolin Bortolotto

2015-03-01

Full Text Available This study aimed to evaluate, in controlled laboratory conditions (temperature of 25±2 °C, relative humidity of 60±10%, and 14/10 h L/D photoperiod, the larval development of Spodoptera eridania (Cramer, 1784 (Lepidoptera, Noctuidae fed with leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 insecticide proteins and its non-Bt isoline. Maize leaves triggered 100% of mortality on S. eridania larvae independently of being Bt or non-Bt plants. However, it was observed that in overall Bt maize (expressing a single or pyramided protein slightly affects the larval development of S. eridania, even under reduced leaf consumption. Therefore, these results showed that Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 can affect the larval development of S. eridania, although it is not a target pest of this plant; however, more research is needed to better understand this evidence. Finally, this study confirms that non-Bt maize leaves are unsuitable food source to S. eridania larvae, suggesting that they are not a potential pest in maize fields.

PLAG1 and USF2 Co-regulate Expression of Musashi-2 in Human Hematopoietic Stem and Progenitor Cells

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Muluken S. Belew

2018-04-01

Full Text Available Summary: MSI2, which is expressed predominantly in hematopoietic stem and progenitor cells (HSPCs, enforces HSPC expansion when overexpressed and is upregulated in myeloid leukemias, indicating its regulated transcription is critical to balanced self-renewal and leukemia restraint. Despite this, little is understood of the factors that enforce appropriate physiological levels of MSI2 in the blood system. Here, we define a promoter region that reports on endogenous expression of MSI2 and identify USF2 and PLAG1 as transcription factors whose promoter binding drives reporter activity. We show that these factors co-regulate, and are required for, efficient transactivation of endogenous MSI2. Coincident overexpression of USF2 and PLAG1 in primitive cord blood cells enhanced MSI2 transcription and yielded cellular phenotypes, including expansion of CD34+ cells in vitro, consistent with that achieved by direct MSI2 overexpression. Global chromatin immunoprecipitation sequencing analyses confirm a preferential co-binding of PLAG1 and USF2 at the promoter of MSI2, as well as regulatory regions corresponding to genes with roles in HSPC homeostasis. PLAG1 and USF2 cooperation is thus an important contributor to stem cell-specific expression of MSI2 and HSPC-specific transcriptional circuitry. : MSI2 is an essential human hematopoietic stem and progenitor cell (HSPC regulator, but knowledge of the mechanisms ensuring its appropriate expression in this context are lacking. Here, Hope and colleagues map the MSI2 promoter functional in hematopoietic cells and identify USF2 and PLAG1 as essential, cooperative enforcers of endogenous MSI2 expression and stemness traits in human HSPCs. Keywords: human hematopoietic stem cells, self-renewal, promoter, transcriptional regulation, transcription factors, Musashi-2, genome-wide DNA binding site mapping, PLAG1, USF2

YY1 positively regulates human UBIAD1 expression

International Nuclear Information System (INIS)

Funahashi, Nobuaki; Hirota, Yoshihisa; Nakagawa, Kimie; Sawada, Natumi; Watanabe, Masato; Suhara, Yoshitomo; Okano, Toshio

2015-01-01

Vitamin K is involved in bone formation and blood coagulation. Natural vitamin K compounds are composed of the plant form phylloquinone (vitamin K 1 ) and a series of bacterial menaquionones (MK-n; vitamin K 2 ). Menadione (vitamin K 3 ) is an artificial vitamin K compound. MK-4 contains 4-isoprenyl as a side group in the 2-methyl-1,4-naphthoquinone common structure and has various bioactivities. UbiA prenyltransferase domain containing 1 (UBIAD1 or TERE1) is the menaquinone-4 biosynthetic enzyme. UBIAD1 transcript expression significantly decreases in patients with prostate carcinoma and overexpressing UBIAD1 inhibits proliferation of a tumour cell line. UBIAD1 mRNA expression is ubiquitous in mouse tissues, and higher UBIAD1 mRNA expression levels are detected in the brain, heart, kidneys and pancreas. Several functions of UBIAD1 have been reported; however, regulation of the human UBIAD1 gene has not been elucidated. Here we report cloning and characterisation of the human UBIAD1 promoter. A 5′ rapid amplification of cDNA ends analysis revealed that the main transcriptional start site was 306 nucleotides upstream of the translation initiation codon. Deletion and mutation analyses revealed the functional importance of the YY1 consensus motif. Electrophoretic gel mobility shift and chromatin immunoprecipitation assays demonstrated that YY1 binds the UBIAD1 promoter in vitro and in vivo. In addition, YY1 small interfering RNA decreased endogenous UBIAD1 mRNA expression and UBIAD1 conversion activity. These results suggest that YY1 up-regulates UBIAD1 expression and UBIAD1 conversion activity through the UBIAD1 promoter. - Highlights: • We cloned the human UBIAD1 promoter. • The functional importance of the YY1 motif was identified in the UBIAD1 promoter. • YY1 binds the UBIAD1 promoter in vitro and in vivo. • Knockdown of YY1 significantly decreased UBIAD1 expression. • YY1 up-regulates UBIAD1 conversion activity through the UBIAD1 promoter

YY1 positively regulates human UBIAD1 expression

Energy Technology Data Exchange (ETDEWEB)

Funahashi, Nobuaki, E-mail: nfunahashi@ri.ncgm.go.jp [Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe (Japan); Department of Metabolic Disorder, Diabetes Research Center, Research Institute, National Center for Global Health and Medicine, Tokyo (Japan); Hirota, Yoshihisa [Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe (Japan); Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka (Japan); Nakagawa, Kimie; Sawada, Natumi; Watanabe, Masato [Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe (Japan); Suhara, Yoshitomo [Department of Bioscience and Engineering, Shibaura Institute of Technology, Saitama (Japan); Okano, Toshio [Department of Hygienic Sciences, Kobe Pharmaceutical University, Kobe (Japan)

2015-05-01

Vitamin K is involved in bone formation and blood coagulation. Natural vitamin K compounds are composed of the plant form phylloquinone (vitamin K{sub 1}) and a series of bacterial menaquionones (MK-n; vitamin K{sub 2}). Menadione (vitamin K{sub 3}) is an artificial vitamin K compound. MK-4 contains 4-isoprenyl as a side group in the 2-methyl-1,4-naphthoquinone common structure and has various bioactivities. UbiA prenyltransferase domain containing 1 (UBIAD1 or TERE1) is the menaquinone-4 biosynthetic enzyme. UBIAD1 transcript expression significantly decreases in patients with prostate carcinoma and overexpressing UBIAD1 inhibits proliferation of a tumour cell line. UBIAD1 mRNA expression is ubiquitous in mouse tissues, and higher UBIAD1 mRNA expression levels are detected in the brain, heart, kidneys and pancreas. Several functions of UBIAD1 have been reported; however, regulation of the human UBIAD1 gene has not been elucidated. Here we report cloning and characterisation of the human UBIAD1 promoter. A 5′ rapid amplification of cDNA ends analysis revealed that the main transcriptional start site was 306 nucleotides upstream of the translation initiation codon. Deletion and mutation analyses revealed the functional importance of the YY1 consensus motif. Electrophoretic gel mobility shift and chromatin immunoprecipitation assays demonstrated that YY1 binds the UBIAD1 promoter in vitro and in vivo. In addition, YY1 small interfering RNA decreased endogenous UBIAD1 mRNA expression and UBIAD1 conversion activity. These results suggest that YY1 up-regulates UBIAD1 expression and UBIAD1 conversion activity through the UBIAD1 promoter. - Highlights: • We cloned the human UBIAD1 promoter. • The functional importance of the YY1 motif was identified in the UBIAD1 promoter. • YY1 binds the UBIAD1 promoter in vitro and in vivo. • Knockdown of YY1 significantly decreased UBIAD1 expression. • YY1 up-regulates UBIAD1 conversion activity through the UBIAD1

The over expression of long non-coding RNA ANRIL promotes epithelial-mesenchymal transition by activating the ATM-E2F1 signaling pathway in pancreatic cancer: An in vivo and in vitro study.

Science.gov (United States)

Chen, Shi; Zhang, Jia-Qiang; Chen, Jiang-Zhi; Chen, Hui-Xing; Qiu, Fu-Nan; Yan, Mao-Lin; Chen, Yan-Ling; Peng, Cheng-Hong; Tian, Yi-Feng; Wang, Yao-Dong

2017-09-01

This study aims to investigate the roles of lncRNA ANRIL in epithelial-mesenchymal transition (EMT) by regulating the ATM-E2F1 signaling pathway in pancreatic cancer (PC). PC rat models were established and ANRIL overexpression and interference plasmids were transfected. The expression of ANRIL, EMT markers (E-cadherin, N-cadherin and Vimentin) and ATM-E2F1 signaling pathway-related proteins (ATM, E2F1, INK4A, INK4B and ARF) were detected. Small molecule drugs were applied to activate and inhibit the ATM-E2F1 signaling pathway. Transwell assay and the scratch test were adopted to detect cell invasion and migration abilities. ANRIL expression in the PC cells was higher than in normal pancreatic duct epithelial cells. In the PC rat models and PC cells, ANRIL interference promoted the expressions of INK4B, INK4A, ARF and E-cadherin, while reduced N-cadherin and Vimentin expression. Over-expressed ANRIL decreased the expression of INK4B, INK4A, ARF and E-cadherin, but raised N-cadherin and Vimentin expressions. By inhibiting the ATM-E2F1 signaling pathway in PC cells, E-cadherin expression increased but N-cadherin and Vimentin expressions decreased. After ANRIL was silenced or the ATM-E2F1 signaling pathway inhibited, PC cell migration and invasion abilities were decreased. In conclusion, over-expression of lncRNA ANRIL can promote EMT of PC cells by activating the ATM-E2F1 signaling pathway. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioinformatic detection of E47, E2F1 and SREBP1 transcription factors as potential regulators of genes associated to acquisition of endometrial receptivity

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Croxatto Horacio B

2011-01-01

Full Text Available Abstract Background The endometrium is a dynamic tissue whose changes are driven by the ovarian steroidal hormones. Its main function is to provide an adequate substrate for embryo implantation. Using microarray technology, several reports have provided the gene expression patterns of human endometrial tissue during the window of implantation. However it is required that biological connections be made across these genomic datasets to take full advantage of them. The objective of this work was to perform a research synthesis of available gene expression profiles related to acquisition of endometrial receptivity for embryo implantation, in order to gain insights into its molecular basis and regulation. Methods Gene expression datasets were intersected to determine a consensus endometrial receptivity transcript list (CERTL. For this cluster of genes we determined their functional annotations using available web-based databases. In addition, promoter sequences were analyzed to identify putative transcription factor binding sites using bioinformatics tools and determined over-represented features. Results We found 40 up- and 21 down-regulated transcripts in the CERTL. Those more consistently increased were C4BPA, SPP1, APOD, CD55, CFD, CLDN4, DKK1, ID4, IL15 and MAP3K5 whereas the more consistently decreased were OLFM1, CCNB1, CRABP2, EDN3, FGFR1, MSX1 and MSX2. Functional annotation of CERTL showed it was enriched with transcripts related to the immune response, complement activation and cell cycle regulation. Promoter sequence analysis of genes revealed that DNA binding sites for E47, E2F1 and SREBP1 transcription factors were the most consistently over-represented and in both up- and down-regulated genes during the window of implantation. Conclusions Our research synthesis allowed organizing and mining high throughput data to explore endometrial receptivity and focus future research efforts on specific genes and pathways. The discovery of possible

Interplay between H1 and HMGN epigenetically regulates OLIG1&2 expression and oligodendrocyte differentiation.

Science.gov (United States)

Deng, Tao; Postnikov, Yuri; Zhang, Shaofei; Garrett, Lillian; Becker, Lore; Rácz, Ildikó; Hölter, Sabine M; Wurst, Wolfgang; Fuchs, Helmut; Gailus-Durner, Valerie; de Angelis, Martin Hrabe; Bustin, Michael

2017-04-07

An interplay between the nucleosome binding proteins H1 and HMGN is known to affect chromatin dynamics, but the biological significance of this interplay is still not clear. We find that during embryonic stem cell differentiation loss of HMGNs leads to down regulation of genes involved in neural differentiation, and that the transcription factor OLIG2 is a central node in the affected pathway. Loss of HMGNs affects the expression of OLIG2 as well as that of OLIG1, two transcription factors that are crucial for oligodendrocyte lineage specification and nerve myelination. Loss of HMGNs increases the chromatin binding of histone H1, thereby recruiting the histone methyltransferase EZH2 and elevating H3K27me3 levels, thus conferring a repressive epigenetic signature at Olig1&2 sites. Embryonic stem cells lacking HMGNs show reduced ability to differentiate towards the oligodendrocyte lineage, and mice lacking HMGNs show reduced oligodendrocyte count and decreased spinal cord myelination, and display related neurological phenotypes. Thus, the presence of HMGN proteins is required for proper expression of neural differentiation genes during embryonic stem cell differentiation. Specifically, we demonstrate that the dynamic interplay between HMGNs and H1 in chromatin epigenetically regulates the expression of OLIG1&2, thereby affecting oligodendrocyte development and myelination, and mouse behavior. Published by Oxford University Press on behalf of Nucleic Acids Research 2016.

A lentiviral vector with expression controlled by E2F-1: A potential tool for the study and treatment of proliferative diseases

International Nuclear Information System (INIS)

Strauss, Bryan E.; Patricio, Juliana Rotelli; Vieira de Carvalho, Anna Carolina; Bajgelman, Marcio C.

2006-01-01

We have constructed a lentiviral vector with expression limited to cells presenting active E2F-1 protein, a potential advantage for gene therapy of proliferative diseases. For the FE2FLW vector, the promoter region of the human E2F-1 gene was utilized to drive expression of luciferase cDNA, included as a reporter of viral expression. Primary, immortalized, and transformed cells were transduced with the FE2FLW vector and cell cycle alterations were induced with serum starvation/replacement, contact inhibition or drug treatment, revealing cell cycle-dependent changes in reporter activity. Forced E2F-1 expression, but not E2F-2 or E2F-3, increased reporter activity, indicating a major role for this factor in controlling expression from the FE2FLW virus. We show the utility of this vector as a reporter of E2F-1 and proliferation-dependent cellular alterations upon cytotoxic/cytostatic treatment, such as the introduction of tumor suppressor genes. We propose that the FE2FLW vector may be a starting point for the development of gene therapy strategies for proliferative diseases, such as cancer or restinosis

Widespread Over-Expression of the X Chromosome in Sterile F1 Hybrid Mice

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Good, Jeffrey M.; Giger, Thomas; Dean, Matthew D.; Nachman, Michael W.

2010-01-01

The X chromosome often plays a central role in hybrid male sterility between species, but it is unclear if this reflects underlying regulatory incompatibilities. Here we combine phenotypic data with genome-wide expression data to directly associate aberrant expression patterns with hybrid male sterility between two species of mice. We used a reciprocal cross in which F1 males are sterile in one direction and fertile in the other direction, allowing us to associate expression differences with sterility rather than with other hybrid phenotypes. We found evidence of extensive over-expression of the X chromosome during spermatogenesis in sterile but not in fertile F1 hybrid males. Over-expression was most pronounced in genes that are normally expressed after meiosis, consistent with an X chromosome-wide disruption of expression during the later stages of spermatogenesis. This pattern was not a simple consequence of faster evolutionary divergence on the X chromosome, because X-linked expression was highly conserved between the two species. Thus, transcriptional regulation of the X chromosome during spermatogenesis appears particularly sensitive to evolutionary divergence between species. Overall, these data provide evidence for an underlying regulatory basis to reproductive isolation in house mice and underscore the importance of transcriptional regulation of the X chromosome to the evolution of hybrid male sterility. PMID:20941395

Copy number variations of E2F1: a new genetic risk factor for testicular cancer.

Science.gov (United States)

Rocca, Maria Santa; Di Nisio, Andrea; Marchiori, Arianna; Ghezzi, Marco; Opocher, Giuseppe; Foresta, Carlo; Ferlin, Alberto

2017-03-01

Testicular germ cell tumor (TGCT) is one of the most heritable forms of cancer. In last years, many evidence suggested that constitutional genetic factors, mainly single nucleotide polymorphisms, can increase its risk. However, the possible contribution of copy number variations (CNVs) in TGCT susceptibility has not been substantially addressed. Indeed, an increasing number of studies have focused on the effect of CNVs on gene expression and on the role of these structural genetic variations as risk factors for different forms of cancer. E2F1 is a transcription factor that plays an important role in regulating cell growth, differentiation, apoptosis and response to DNA damage. Therefore, deficiency or overexpression of this protein might significantly influence fundamental biological processes involved in cancer development and progression, including TGCT. We analyzed E2F1 CNVs in 261 cases with TGCT and 165 controls. We found no CNVs in controls, but 17/261 (6.5%) cases showed duplications in E2F1 Blot analysis demonstrated higher E2F1 expression in testicular samples of TGCT cases with three copies of the gene. Furthermore, we observed higher phosphorylation of Akt and mTOR in samples with E2F1 duplication. Interestingly, normal, non-tumoral testicular tissue in patient with E2F1 duplication showed lower expression of E2F1 and lower AKT/mTOR phosphorylation with respect to adjacent tumor tissue. Furthermore, increased expression of E2F1 obtained in vitro in NTERA-2 testicular cell line induced increased AKT/mTOR phosphorylation. This study suggests for the first time an involvement of E2F1 CNVs in TGCT susceptibility and supports previous preliminary data on the importance of AKT/mTOR signaling pathway in this cancer. © 2017 Society for Endocrinology.

SENP1 attenuates the liver fibrosis through down-regulating the expression of SMAD2.

Science.gov (United States)

Wu, Linshi; Qiu, Weiqing; Sun, Jianhua; Wang, Jian

2018-01-01

To investigate whether SENP1 could play a regulating role in the liver fibrosis process, the Sprague-Dawley (SD) rats were used to establish the liver fibrosis rat models by intraperitoneally injecting with 1 ml/kg of 10% CCl 4 , while the control normal rats were injected with olive oil. Then confirmation experiments to verify the successful establishment of these models were conducted by detecting the cellular and lobular architecture, and liver function indexes using hematoxylin-eosin staining, Masson's trichrome staining and microplate method, respectively. In addition, the expression levels of fibrosis markers including collagen I, collagen III, α-SMA and TGF-β1 were inspected using quantitative real-time PCR (qRT-PCR), as well as SMAD2. Subsequently, the relative mRNA and protein level of SENP1 was also determined via qRT-PCR and western blot analysis. Next, the HSC-T6 cells of SENP1 knock-down were constructed and used to test the relative protein expression levels of α-SMA and SMAD2 in these cells. The results of hematoxylin-eosin staining, Masson's trichrome staining and microplate method turned out that the rat liver fibrosis models were constructed successfully, which was further confirmed by the increased expression of collagen I, collagen III, α-SMA and TGF-β1 in mRNA and protein level, as well as SMAD2. Then the expression of SENP1 was overexpressed in the rat liver fibrosis models induced by CCl 4 and the TGF-β1 treatment could increase the protein expression level of collagen I, collagen III and α-SMA. Lastly, the SENP1 knockdown HSC-T6 cells were successfully constructed, while the silence of SENP1 down-regulated the protein expression of α-SMA and SMAD2. In conclusion, this study provided a new regulation mechanism about the liver fibrosis process. Copyright © 2017 Elsevier Inc. All rights reserved.

Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression

Energy Technology Data Exchange (ETDEWEB)

Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong; Khanal, Tilak; Choi, Jae Ho [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Chung, Young Chul [Department of Food Science and Culinary, International University of Korea, Jinju (Korea, Republic of); Jeong, Tae Cheon, E-mail: taecheon@ynu.ac.kr [College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

2014-10-01

Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 and CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. - Graphical abstract: Schematic of the CYP1A1 and CYP1B1 gene regulation by metformin. - Highlights: • Metformin inhibits CYP1A1 and CYP1B1 expression. • Metformin down-regulates the AhR signaling. • Metformin reduces Sp1 protein expression. • Metformin suppresses TDO expression.

Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression

International Nuclear Information System (INIS)

Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong; Khanal, Tilak; Choi, Jae Ho; Chung, Young Chul; Jeong, Tae Cheon; Jeong, Hye Gwang

2014-01-01

Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 and CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. - Graphical abstract: Schematic of the CYP1A1 and CYP1B1 gene regulation by metformin. - Highlights: • Metformin inhibits CYP1A1 and CYP1B1 expression. • Metformin down-regulates the AhR signaling. • Metformin reduces Sp1 protein expression. • Metformin suppresses TDO expression

The F-BAR domains from srGAP1, srGAP2 and srGAP3 regulate membrane deformation differently

Science.gov (United States)

Coutinho-Budd, Jaeda; Ghukasyan, Vladimir; Zylka, Mark J.; Polleux, Franck

2012-01-01

Summary Coordination of membrane deformation and cytoskeletal dynamics lies at the heart of many biological processes critical for cell polarity, motility and morphogenesis. We have recently shown that Slit-Robo GTPase-activating protein 2 (srGAP2) regulates neuronal morphogenesis through the ability of its F-BAR domain to regulate membrane deformation and induce filopodia formation. Here, we demonstrate that the F-BAR domains of two closely related family members, srGAP1 and srGAP3 [designated F-BAR(1) and F-BAR(3), respectively] display significantly different membrane deformation properties in non-neuronal COS7 cells and in cortical neurons. F-BAR(3) induces filopodia in both cell types, though less potently than F-BAR(2), whereas F-BAR(1) prevents filopodia formation in cortical neurons and reduces plasma membrane dynamics. These three F-BAR domains can heterodimerize, and they act synergistically towards filopodia induction in COS7 cells. As measured by fluorescence recovery after photobleaching, F-BAR(2) displays faster molecular dynamics than F-BAR(3) and F-BAR(1) at the plasma membrane, which correlates well with its increased potency to induce filopodia. We also show that the molecular dynamic properties of F-BAR(2) at the membrane are partially dependent on F-Actin. Interestingly, acute phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] depletion in cells does not interfere with plasma membrane localization of F-BAR(2), which is compatible with our result showing that F-BAR(2) binds to a broad range of negatively-charged phospholipids present at the plasma membrane, including phosphatidylserine (PtdSer). Overall, our results provide novel insights into the functional diversity of the membrane deformation properties of this subclass of F-BAR-domains required for cell morphogenesis. PMID:22467852

RCC2 over-expression in tumor cells alters apoptosis and drug sensitivity by regulating Rac1 activation.

Science.gov (United States)

Wu, Nan; Ren, Dong; Li, Su; Ma, Wenli; Hu, Shaoyan; Jin, Yan; Xiao, Sheng

2018-01-10

Small GTP binding protein Rac1 is a component of NADPH oxidases and is essential for superoxide-induced cell death. Rac1 is activated by guanine nucleotide exchange factors (GEFs), and this activation can be blocked by regulator of chromosome condensation 2 (RCC2), which binds the switch regions of Rac1 to prevent access from GEFs. Three cancer cell lines with up- or down-regulation of RCC2 were used to evaluate cell proliferation, apoptosis, Rac1 signaling and sensitivity to a group of nine chemotherapeutic drugs. RCC2 expression in lung cancer and ovarian cancer were studied using immunochemistry stain of tumor tissue arrays. Forced RCC2 expression in tumor cells blocked spontaneous- or Staurosporine (STS)-induced apoptosis. In contrast, RCC2 knock down in these cells resulted in increased apoptosis to STS treatment. The protective activity of RCC2 on apoptosis was revoked by a constitutively activated Rac1, confirming a role of RCC2 in apoptosis by regulating Rac1. In an immunohistochemistry evaluation of tissue microarray, RCC2 was over-expressed in 88.3% of primary lung cancer and 65.2% of ovarian cancer as compared to non-neoplastic lung and ovarian tissues, respectively. Because chemotherapeutic drugs can kill tumor cells by activating Rac1/JNK pathway, we suspect that tumors with RCC2 overexpression would be more resistant to these drugs. Tumor cells with forced RCC2 expression indeed had significant difference in drug sensitivity compared to parental cells using a panel of common chemotherapeutic drugs. RCC2 regulates apoptosis by blocking Rac1 signaling. RCC2 expression in tumor can be a useful marker for predicting chemotherapeutic response.

Larval development of Spodoptera eridania and Spodoptera frugiperda fed on fresh ear of field corn expressing the Bt proteins (Cry1F and Cry1F + Cry1A.105 + Cry2Ab2)

OpenAIRE

Bortolotto,Orcial Ceolin; Bueno,Adeney de Freitas; Queiroz,Ana Paula de; Silva,Gabriela Vieira

2016-01-01

ABSTRACT: The objective of this study was to evaluate extent of larval period, larval survival (%), food consumption, and pupal biomass of Spodoptera eridania and Spodoptera frugiperda (Lepidoptera: Noctuidae ) fed on fresh ears of field corn expressing Bt proteins (Cry1F and Cry1F+Cry1A.105+Cry2Ab2). Larvae of Spodoptera spp. survived less than two days when they consumed Bt corncobs and showed 100% mortality. Spodoptera eridania reared on non-Bt corn cobs showed higher larval development (...

Calcium regulates caveolin-1 expression at the transcriptional level

International Nuclear Information System (INIS)

Yang, Xiao-Yan; Huang, Cheng-Cheng; Kan, Qi-Ming; Li, Yan; Liu, Dan; Zhang, Xue-Cheng; Sato, Toshinori; Yamagata, Sadako; Yamagata, Tatsuya

2012-01-01

Highlights: ► Caveolin-1 expression is regulated by calcium signaling at the transcriptional level. ► An inhibitor of or siRNA to L-type calcium channel suppressed caveolin-1 expression. ► Cyclosporine A or an NFAT inhibitor markedly reduced caveolin-1 expression. ► Caveolin-1 regulation by calcium signaling is observed in several mouse cell lines. -- Abstract: Caveolin-1, an indispensable component of caveolae serving as a transformation suppressor protein, is highly expressed in poorly metastatic mouse osteosarcoma FBJ-S1 cells while highly metastatic FBJ-LL cells express low levels of caveolin-1. Calcium concentration is higher in FBJ-S1 cells than in FBJ-LL cells; therefore, we investigated the possibility that calcium signaling positively regulates caveolin-1 in mouse FBJ-S1 cells. When cells were treated with the calcium channel blocker nifedipine, cyclosporin A (a calcineurin inhibitor), or INCA-6 (a nuclear factor of activated T-cells [NFAT] inhibitor), caveolin-1 expression at the mRNA and protein levels decreased. RNA silencing of voltage-dependent L-type calcium channel subunit alpha-1C resulted in suppression of caveolin-1 expression. This novel caveolin-1 regulation pathway was also identified in mouse NIH 3T3 cells and Lewis lung carcinoma cells. These results indicate that caveolin-1 is positively regulated at the transcriptional level through a novel calcium signaling pathway mediated by L-type calcium channel/Ca 2+ /calcineurin/NFAT.

Isolation and expression analysis of FTZ-F1 encoding gene of black rock fish ( Sebastes schlegelii)

Science.gov (United States)

Shafi, Muhammad; Wang, Yanan; Zhou, Xiaosu; Ma, Liman; Muhammad, Faiz; Qi, Jie; Zhang, Quanqi

2013-03-01

Sex related FTZ-F1 is a transcriptional factor regulating the expression of fushi tarazu (a member of the orphan nuclear receptors) gene. In this study, FTZ-F1 gene ( FTZ-F1) was isolated from the testis of black rockfish ( Sebastes schlegeli) by homology cloning. The full-length cDNA of S. schlegeli FTZ-F1 ( ssFTZ-F1) contained a 232bp 5' UTR, a 1449bp ORF encoding FTZ-F1 (482 amino acid residules in length) with an estimated molecular weight of 5.4kD and a 105bp 3' UTR. Sequence, tissue distribution and phylogenic analysis showed that ssFTZ-F1 belonged to FTZ group, holding highly conserved regions including I, II and III FTZ-F1 boxes and an AF-2 hexamer. Relatively high expression was observed at different larva stages. In juveniles (105 days old), the transcript of ssFTZ-F1 can be detected in all tissues and the abuncance of the gene transcript in testis, ovary, spleen and brain was higher than that in other tissues. In mature fish, the abundance of gene transcript was higher in testis, ovary, spleen and brain than that in liver (trace amount), and the gene was not transcribed in other tissues. The highest abundance of gene transcript was always observed in gonads of both juvenile and mature fish. In addition, the abundance of gene transcript in male tissues were higher than that in female tissue counterparts ( P<0.05).

Synthesis of 2'-deoxy-2'-[{sup 18}F]-fluoro-5-iodo-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]-FIAU) and micro-PET imaging of suicide gene expression in tumor-bearing nude mice

Energy Technology Data Exchange (ETDEWEB)

Alauddin, M.M.; Shahinian, A.; Park, R.; Tohme, M.; Fissekis, J.D.; Conti, P.S. [Univ. of Southern California, Los Angeles, CA (United States). PET Imaging Science Center

2004-07-01

Herpes simplex virus type-1 thymidine kinase (HSV1-tk) is being used as a suicide gene for gene therapy of cancer. An in vivo method to assess the HSV1-tk enzyme activity after gene transfer is desirable to monitor gene expression as an indicator of gene delivery. Imaging of the HSV1-tk reporter gene along with various reporter probes is of current interest. We originally developed [{sup 18}F]-FHPG and [{sup 18}F]-FHBG for PET imaging of HSV1-tk gene expression and demonstrated that [{sup 18}F]-FHBG is more useful than [{sup 18}F]-FHPG for this purpose. [{sup 124}I]-FIAU has been shown to be a potential PET imaging agent for HSV1-tk gene expression, and is superior to [{sup 18}F]-FHPG and [{sup 18}F]-FHBG. We also demonstrated that radiolabeled FMAU can be used as a marker for HSV-tk gene expression, and is superior to [{sup 18}F]-FHPG and [{sup 18}F]-FHBG. Earlier we reported a synthesis for 2'-deoxy-2'-[{sup 18}F]fluoro-5-methyl-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]-FMAU) and some other 5-substituted nucleosides. We have synthesized now [{sup 18}F]-FIAU, used the tracer for micro-PET imaging of suicide gene expression in tumor-bearing nude mice, and compared the results with earlier studies using [{sup 14}C]-FMAU. (orig.)

5-[{sup 18}F]Fluoroalkyl pyrimidine nucleosides: probes for positron emission tomography imaging of herpes simplex virus type 1 thymidine kinase gene expression

Energy Technology Data Exchange (ETDEWEB)

Chacko, Ann-Marie [Institute for Environmental Medicine, Targeted Therapeutics Program, University of Pennsylvania, Philadelphia, PA 19104 (United States); Blankemeyer, Eric; Lieberman, Brian P.; Qu, Wenchao [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Kung, Hank F. [Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of Pharmacology, University of Pennsylvania, Philadelphia, PA 19104 (United States)], E-mail: kunghf@gmail.com

2009-01-15

Introduction: The preliminary in vivo evaluation of novel 5-[{sup 18}F]fluoroalkyl-2'-deoxyuridines ([{sup 18}F]FPrDU, [{sup 18}F]FBuDU, [{sup 18}F]FPeDU; [{sup 18}F]1a-c, respectively) and 2'-fluoro-2'-deoxy-5-[{sup 18}F]fluoroalkyl-1-{beta}-D-arabinofuranosyl uracils ([{sup 18}F]FFPrAU, [{sup 18}F]FFBuAU, [{sup 18}F]FFPeAU; [{sup 18}F]1d-f, respectively) as probes for imaging herpes simplex virus type 1 thymidine kinase (HSV1-tk) gene expression is described. Methods: [{sup 18}F]1a-f were successfully synthesized by a rapid and efficient two-step one-pot nucleophilic fluorination reaction using 5-O-mesylate precursors and [{sup 18}F]F{sup -}. For in vivo studies, tumor xenografts were grown in nude mice by implanting RG2 cells stably expressing HSV1-tk (RG2TK+) and wild-type cells (RG2). Results: Biodistribution studies at 2 h pi revealed that the uptake of [{sup 18}F]1a-b and [{sup 18}F]1d-e in RG2TK+ tumors was not significantly different from control tumors. However, [{sup 18}F]1c and [{sup 18}F]1f had an average 1.6- and 1.7-fold higher uptake in RG2TK+ tumors than control RG2 tumors. Blood activity curves for [{sup 18}F]1c and [{sup 18}F]1f highlight rapid clearance of radioactivity in the blood. Dynamic small animal PET (A-PET) imaging studies of tumor-bearing mice with [{sup 18}F]1c and [{sup 18}F]1f showed higher initial uptake (3.5- and 1.4-fold, respectively) in RG2TK+ tumors than in control tumors, with continued washout of activity from both tumors over time. Conclusions: Biological evaluations suggest that [{sup 18}F]1c and [{sup 18}F]1f may have limited potential for imaging HSV1-tk gene expression due to fast washout of activity from the blood, thus significantly decreasing sensitivity and specificity of tracer accumulation in HSV1-tk-expressing tumors.

Network-based differential gene expression analysis suggests cell cycle related genes regulated by E2F1 underlie the molecular difference between smoker and non-smoker lung adenocarcinoma

Science.gov (United States)

2013-01-01

Background Differential gene expression (DGE) analysis is commonly used to reveal the deregulated molecular mechanisms of complex diseases. However, traditional DGE analysis (e.g., the t test or the rank sum test) tests each gene independently without considering interactions between them. Top-ranked differentially regulated genes prioritized by the analysis may not directly relate to the coherent molecular changes underlying complex diseases. Joint analyses of co-expression and DGE have been applied to reveal the deregulated molecular modules underlying complex diseases. Most of these methods consist of separate steps: first to identify gene-gene relationships under the studied phenotype then to integrate them with gene expression changes for prioritizing signature genes, or vice versa. It is warrant a method that can simultaneously consider gene-gene co-expression strength and corresponding expression level changes so that both types of information can be leveraged optimally. Results In this paper, we develop a gene module based method for differential gene expression analysis, named network-based differential gene expression (nDGE) analysis, a one-step integrative process for prioritizing deregulated genes and grouping them into gene modules. We demonstrate that nDGE outperforms existing methods in prioritizing deregulated genes and discovering deregulated gene modules using simulated data sets. When tested on a series of smoker and non-smoker lung adenocarcinoma data sets, we show that top differentially regulated genes identified by the rank sum test in different sets are not consistent while top ranked genes defined by nDGE in different data sets significantly overlap. nDGE results suggest that a differentially regulated gene module, which is enriched for cell cycle related genes and E2F1 targeted genes, plays a role in the molecular differences between smoker and non-smoker lung adenocarcinoma. Conclusions In this paper, we develop nDGE to prioritize

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

Science.gov (United States)

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

2009-05-01

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

Comportamiento productivo en híbridos de jitomate y sus respectivas poblaciones F2

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J. Martínez-Solís

2005-01-01

Full Text Available Debido a que el precio de semilla híbrida de jitomate es muy alto, muchos agricultores utilizan generaciones F2 en parcelas comerciales. Por esta razón con el propósito de evaluar el comportamiento entre genotipos de jitomate F1 y F2, 37 híbridos y sus respectivas generaciones F2 fueron establecidos en invernadero. La mayoría de las generaciones F2 presentaron menor peso total de fruto por planta y número de frutos por planta con respecto a sus F1; sin embargo, el efecto fue estadísticamente significativo sólo en dos genotipos tipo bola de hábito de crecimiento determinado y cuatro genotipos tipo bola de hábito de crecimiento indeterminado, los cuales abatieron su producción de fruto de F2 en al menos 20 %

BMP6 down-regulates GDNF expression through SMAD1/5 and ERK1/2 signaling pathways in human granulosa-lutein cells.

Science.gov (United States)

Zhang, Xin-Yue; Chang, Hsun-Ming; Taylor, Elizabeth L; Leung, Peter C K; Liu, Rui-Zhi

2018-05-09

Bone morphogenetic protein 6 (BMP6) is a critical regulator of follicular development that is expressed in mammalian oocytes and granulosa cells. Glial cell line-derived neurotrophic factor (GDNF) is an intraovarian neurotrophic factor that plays an essential role in regulating mammalian oocyte maturation. The aim of this study was to investigate the effect of BMP6 on the regulation of GDNF expression and the potential underlying mechanisms. We used an established immortalized human granulosa cell line (SVOG cells) and primary human granulosa-lutein cells as in vitro cell models. Our results showed that BMP6 significantly down-regulated the expression of GDNF in both SVOG and primary human granulosa-lutein cells. Using dual inhibition approaches (kinase receptor inhibitor and small interfering RNA knockdown), our results showed that both ALK2 and ALK3 are involved in BMP6-induced down-regulation of GDNF. In addition, BMP6 induced the phosphorylation of SMAD1/5/8 and ERK1/2 but not AKT or p38. Among three downstream mediators, both SMAD1 and SMAD5 are involved in BMP6-induced down-regulation of GDNF. Moreover, concomitant knockdown of endogenous SMAD4 and inhibition of ERK1/2 activity completely reversed BMP6-induced down-regulation of GDNF, indicating that both SMAD and ERK1/2 signaling pathways are required for the regulatory effect of BMP6 on GDNF expression. Our findings suggest an additional role for an intrafollicular growth factor in regulating follicular function through their paracrine interactions in human granulosa cells.

The ASK1 gene regulates B function gene expression in cooperation with UFO and LEAFY in Arabidopsis.

Science.gov (United States)

Zhao, D; Yu, Q; Chen, M; Ma, H

2001-07-01

The Arabidopsis floral regulatory genes APETALA3 (AP3) and PISTILLATA (PI) are required for the B function according to the ABC model for floral organ identity. AP3 and PI expression are positively regulated by the LEAFY (LFY) and UNUSUAL FLORAL ORGANS (UFO) genes. UFO encodes an F-box protein, and we have shown previously that UFO genetically interacts with the ASK1 gene encoding a SKP1 homologue; both the F-box containing protein and SKP1 are subunits of ubiquitin ligases. We show here that the ask1-1 mutation can enhance the floral phenotypes of weak lfy and ap3 mutants; therefore, like UFO, ASK1 also interacts with LFY and AP3 genetically. Furthermore, our results from RNA in situ hybridizations indicate that ASK1 regulates early AP3 and PI expression. These results support the idea that UFO and ASK1 together positively regulate AP3 and PI expression. We propose that the UFO and ASK1 proteins are components of a ubiquitin ligase that mediates the proteolysis of a repressor of AP3 and PI expression. Our genetic studies also indicate that ASK1 and UFO play a role in regulating the number of floral organ primordia, and we discuss possible mechanisms for such a regulation.

Transcriptomic analysis of host immune and cell death responses associated with the influenza A virus PB1-F2 protein.

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Ronan Le Goffic

2011-08-01

Full Text Available Airway inflammation plays a major role in the pathogenesis of influenza viruses and can lead to a fatal outcome. One of the challenging objectives in the field of influenza research is the identification of the molecular bases associated to the immunopathological disorders developed during infection. While its precise function in the virus cycle is still unclear, the viral protein PB1-F2 is proposed to exert a deleterious activity within the infected host. Using an engineered recombinant virus unable to express PB1-F2 and its wild-type homolog, we analyzed and compared the pathogenicity and host response developed by the two viruses in a mouse model. We confirmed that the deletion of PB1-F2 renders the virus less virulent. The global transcriptomic analyses of the infected lungs revealed a potent impact of PB1-F2 on the response developed by the host. Thus, after two days post-infection, PB1-F2 invalidation severely decreased the number of genes activated by the host. PB1-F2 expression induced an increase in the number and level of expression of activated genes linked to cell death, inflammatory response and neutrophil chemotaxis. When generating interactive gene networks specific to PB1-F2, we identified IFN-γ as a central regulator of PB1-F2-regulated genes. The enhanced cell death of airway-recruited leukocytes was evidenced using an apoptosis assay, confirming the pro-apoptotic properties of PB1-F2. Using a NF-kB luciferase adenoviral vector, we were able to quantify in vivo the implication of NF-kB in the inflammation mediated by the influenza virus infection; we found that PB1-F2 expression intensifies the NF-kB activity. Finally, we quantified the neutrophil recruitment within the airways, and showed that this type of leukocyte is more abundant during the infection of the wild-type virus. Collectively, these data demonstrate that PB1-F2 strongly influences the early host response during IAV infection and provides new insights into the

Deregulated expression of A1, Bcl-2, Bcl-xL, and Mcl-1 antiapoptotic proteins and Bid, Bad, and Bax proapoptotic genes in polycythemia vera patients

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Elainy Patricia Lino Gasparotto

2011-12-01

Full Text Available Apoptosis deregulation might have a role in the pathophysiology of polycythemia vera (PV. This study evaluated Bcl-2 molecule expression in CD34+ cells and leukocytes in 12 PV patients. Gene expression was investigated by real time PCR using SybrGreen Quantitect kit and protein expression was evaluated by western-blotting. JAK2 V617F mutation was detected according to Baxter et al (2005. CD34+ cells from PV patients presented higher levels of A1 and Mcl-1 expression (median: 22.6 and 5.2, respectively in comparison with controls (0.9 and 0.5, p=0.004 and p=0.020; while Bcl-2 and Bcl-xL expression decreased in PV patients (0.18 and 1.19 compared with controls (1.39 and 2.01, p=0.006 and p=0.020. CD34+ cells in PV patients showed an elevated Bid expression (14.4 in comparison with healthy subjects (1.0; p=0.002. Patients' leukocytes showed an A1 augmentation (7.41, p=0.001 and a reduced expression of Bax (0.19; p=0.040 and Bad (0.2; p=0.030. There was no correlation between JAK2 V617F allele burden and molecular expression. PV patients showed alterations in Bcl-2 members' expression, which may interfere with control of apoptotic machinery and contribute to disease pathogenesis.A desregulação da apoptose parece participar da fisiopatologia da policitemia vera (PV. Este estudo avaliou a expressão das moléculas da família Bcl-2 em células hematopoéticas CD34 + e leucócitos de 12 pacientes com PV. Foram realizados: a quantificação da expressão gênica por PCR em tempo real utilizando kit Sybrgreen Quantitect, avaliação da expressão de proteínas por western-blot e detecção da mutação JAK2 V617F segundo Baxter et al. (2005. Células CD34 + dos pacientes com PV apresentaram maior expressão de A1 e Mcl-1 (mediana: 22,6 e 5,2, respectivamente em comparação com controles (0,9 e 0,5, p = 0,004 e p = 0,020 e expressão de Bcl-2 e Bcl-xL diminuída nestes pacientes (0,18 e 1,19 em relação aos controles (1,39 e 2,01, p = 0,006 e p = 0

Regulação da expressão gênica das UCP2 e UCP3 pela restrição energética,jejum e exercício físico UCP2 and UCP3 genic expression: regulation by food restriction, fasting and physical exercise

Directory of Open Access Journals (Sweden)

Renata Polessi Boschini

2005-12-01

Full Text Available O tecido adiposo marrom, onde se localiza a proteína desacopladora 1 (UCP1 - uncoupling protein 1, é um tecido termogênico presente somente nos pequenos mamíferos e neonatos, com função de manter temperatura e peso corporal estáveis quando da exposição ao frio ou consumo de dietas hipercalóricas. Como a UCP1 está localizada exclusivamente no tecido adiposo marrom, tecido pouco expressado em adultos, os estudos dão ênfase às proteínas desacopladoras 2 e 3 (UCP2 e UCP3, proteínas homólogas à UCP1, expressas em múltiplos tecidos e nos músculos esqueléticos, respectivamente. A atividade física provoca aumento do RNAm da UCP2 e UCP3, questiona-se, porém, se este aumento é devido a mudanças no metabolismo de gordura ou a mudanças no metabolismo energético. Durante a restrição energética ou jejum, há depleção de gordura corporal e aumento da concentração plasmática de ácidos graxos livres, com regulação positiva da UCP2 e da UCP3 no músculo e aumento da oxidação lipídica. A concentração elevada de ácidos graxos representa sinal intracelular importante na indução da expressão das UCP no músculo, o que pode estar ligado à sua utilização como combustível até que ocorra aumento da demanda do organismo para dissipação da energia. No entanto, discute-se se a UCP2 e a UCP3 no músculo esquelético têm como função mediar a termogênese ou regular a oxidação de lipídios.The brown adipose tissue, where the uncoupling protein 1 (UCP1 is located, is a thermogenetic tissue only present in small mammals and neonates, with the function of keeping the temperature and body weight stable when exposed to either cold or a hypercaloric diet. Since the UCP1 is located exclusively in brown adipose tissue, and this tissue has little expression in human adults, the studies have emphasized the UCP2 and UCP3, homologous proteins to the UCP1, expressed in multiple tissues and skeletal muscle, respectively. Physical

Synthesis of 2'-deoxy-2'-[{sup 18}F]-fluoro-5-ethyl-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]-FEAU) and micro-PET imaging of HSV-tk gene expression in tumor-bearing nude mice

Energy Technology Data Exchange (ETDEWEB)

Alauddin, M.M.; Shahinian, A.; Park, R.; Tohme, M.; Fissekis, J.D.; Conti, P.S. [Univ. of Southern California, Los Angeles, CA (United States). PET Imaging Science Center

2004-07-01

Herpes simplex virus type-1 thymidine kinase (HSV1-tk) is being used as a suicide gene for gene therapy of cancer. An in vivo method to assess the HSV1-tk enzyme activity after gene transfer is desirable to monitor gene expression as an indicator of gene delivery. Imaging of the HSV1-tk reporter gene along with various reporter probes is of current interest. We originally developed [{sup 18}F]-FHPG and [{sup 18}F]-FHBG for PET imaging of HSV1-tk gene expression and demonstrated that [{sup 18}F]-FHBG is more useful than [{sup 18}F]-FHPG for this purpose. [{sup 124}I]-FIAU has been shown to be a potential PET imaging agent for HSV1-tk gene expression, and is superior to [{sup 18}F]-FHPG and [{sup 18}F]-FHBG. We also demonstrated that radiolabeled FMAU can be used as a marker for HSV-tk gene expression, and is superior to [{sup 18}F]-FHPG and [{sup 18}F]-FHBG. Earlier we reported a synthesis for 2'-deoxy-2'-[{sup 18}F]fluoro-5-methyl-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]-FMAU) and some other 5-substituted nucleosides. We have synthesized now [{sup 18}F]-FEAU, used the tracer for micro-PET imaging of suicide gene expression in tumor-bearing nude mice, and compared the results with earlier studies using [{sup 14}C]-FMAU. (orig.)

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells

International Nuclear Information System (INIS)

Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

2016-01-01

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4–5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba 2+ -sensitive inward rectifier K + current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca 2+ imaging study revealed that the hypoxic stress enhanced store-operated Ca 2+ (SOC) entry, which was significantly reduced in the presence of 100 μM Ba 2+ . On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba 2+ . We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca 2+ entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. -- Highlights: •Hypoxic culture of brain endothelial cells (BEC) caused membrane hyperpolarization. •This hyperpolarization was due to the increased expression of Kir2.1 channels. •Hypoxia enhanced store-operated Ca 2+ (SOC) entry via Kir2.1 up-regulation. •Expression levels of putative SOC channels were not affected by hypoxia. �

RUNX1 positively regulates the ErbB2/HER2 signaling pathway through modulating SOS1 expression in gastric cancer cells.

Science.gov (United States)

Mitsuda, Yoshihide; Morita, Ken; Kashiwazaki, Gengo; Taniguchi, Junichi; Bando, Toshikazu; Obara, Moeka; Hirata, Masahiro; Kataoka, Tatsuki R; Muto, Manabu; Kaneda, Yasufumi; Nakahata, Tatsutoshi; Liu, Pu Paul; Adachi, Souichi; Sugiyama, Hiroshi; Kamikubo, Yasuhiko

2018-04-23

The dual function of runt-related transcriptional factor 1 (RUNX1) as an oncogene or oncosuppressor has been extensively studied in various malignancies, yet its role in gastric cancer remains elusive. Up-regulation of the ErbB2/HER2 signaling pathway is frequently-encountered in gastric cancer and contributes to the maintenance of these cancer cells. This signaling cascade is partly mediated by son of sevenless homolog (SOS) family, which function as adaptor proteins in the RTK cascades. Herein we report that RUNX1 regulates the ErbB2/HER2 signaling pathway in gastric cancer cells through transactivating SOS1 expression, rendering itself an ideal target in anti-tumor strategy toward this cancer. Mechanistically, RUNX1 interacts with the RUNX1 binding DNA sequence located in SOS1 promoter and positively regulates it. Knockdown of RUNX1 led to the decreased expression of SOS1 as well as dephosphorylation of ErbB2/HER2, subsequently suppressed the proliferation of gastric cancer cells. We also found that our novel RUNX inhibitor (Chb-M') consistently led to the deactivation of the ErbB2/HER2 signaling pathway and was effective against several gastric cancer cell lines. Taken together, our work identified a novel interaction of RUNX1 and the ErbB2/HER2 signaling pathway in gastric cancer, which can potentially be exploited in the management of this malignancy.

Meis1 regulates Foxn4 expression during retinal progenitor cell differentiation

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Mohammed M. Islam

2013-09-01

The transcription factor forkhead box N4 (Foxn4 is a key regulator in a variety of biological processes during development. In particular, Foxn4 plays an essential role in the genesis of horizontal and amacrine neurons from neural progenitors in the vertebrate retina. Although the functions of Foxn4 have been well established, the transcriptional regulation of Foxn4 expression during progenitor cell differentiation remains unclear. Here, we report that an evolutionarily conserved 129 bp noncoding DNA fragment (Foxn4CR4.2 or CR4.2, located ∼26 kb upstream of Foxn4 transcription start site, functions as a cis-element for Foxn4 regulation. CR4.2 directs gene expression in Foxn4-positive cells, primarily in progenitors, differentiating horizontal and amacrine cells. We further determined that the gene regulatory activity of CR4.2 is modulated by Meis1 binding motif, which is bound and activated by Meis1 transcription factor. Deletion of the Meis1 binding motif or knockdown of Meis1 expression abolishes the gene regulatory activity of CR4.2. In addition, knockdown of Meis1 expression diminishes the endogenous Foxn4 expression and affects cell lineage development. Together, we demonstrate that CR4.2 and its interacting Meis1 transcription factor play important roles in regulating Foxn4 expression during early retinogenesis. These findings provide new insights into molecular mechanisms that govern gene regulation in retinal progenitors and specific cell lineage development.

1α,25(OH)2D3 differentially regulates miRNA expression in human bladder cancer cells.

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Ma, Yingyu; Hu, Qiang; Luo, Wei; Pratt, Rachel N; Glenn, Sean T; Liu, Song; Trump, Donald L; Johnson, Candace S

2015-04-01

Bladder cancer is the fourth most commonly diagnosed cancer in men and eighth leading cause of cancer-related death in the US. Epidemiological and experimental studies strongly suggest a role for 1α,25(OH)2D3 in cancer prevention and treatment. The antitumor activities of 1α,25(OH)2D3 are mediated by the induction of cell cycle arrest, apoptosis, differentiation and the inhibition of angiogenesis and metastasis. miRNAs play important regulatory roles in cancer development and progression. However, the role of 1α,25(OH)2D3 in the regulation of miRNA expression and the potential impact in bladder cancer has not been investigated. Therefore, we studied 1α,25(OH)2D3-regulated miRNA expression profiles in human bladder cancer cell line 253J and the highly tumorigenic and metastatic derivative line 253J-BV by miRNA qPCR panels. 253J and 253J-BV cells express endogenous vitamin D receptor (VDR), which can be further induced by 1α,25(OH)2D3. VDR target gene 24-hydroxylase was induced by 1α,25(OH)2D3 in both cell lines, indicating functional 1α,25(OH)2D3 signaling. The miRNA qPCR panel assay results showed that 253J and 253J-BV cells have distinct miRNA expression profiles. Further, 1α,25(OH)2D3 differentially regulated miRNA expression profiles in 253J and 253J-BV cells in a dynamic manner. Pathway analysis of the miRNA target genes revealed distinct patterns of contribution to the molecular functions and biological processes in the two cell lines. In conclusion, 1α,25(OH)2D3 differentially regulates the expression of miRNAs, which may contribute to distinct biological functions, in human bladder 253J and 253J-BV cells. This article is part of a Special Issue entitled '17th Vitamin D Workshop'. Copyright © 2014 Elsevier Ltd. All rights reserved.

E2F1 promote the aggressiveness of human colorectal cancer by activating the ribonucleotide reductase small subunit M2

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Fang, Zejun [Sanmen People' s Hospital of Zhejiang, Sanmen, Zhejiang, 317100 (China); Gong, Chaoju [Department of Pathology and Pathophysiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058 (China); Liu, Hong [Zhejiang Normal University – Jinhua People' s Hospital Joint Center for Biomedical Research, Jinhua, Zhejiang, 321004 (China); Zhang, Xiaomin; Mei, Lingming [Sanmen People' s Hospital of Zhejiang, Sanmen, Zhejiang, 317100 (China); Song, Mintao [Department of Pathophysiology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS), School of Basic Medicine, Peking Union Medical College (PUMC), Beijing, 100005 (China); Qiu, Lanlan; Luo, Shuchai; Zhu, Zhihua; Zhang, Ronghui; Gu, Hongqian [Sanmen People' s Hospital of Zhejiang, Sanmen, Zhejiang, 317100 (China); Chen, Xiang, E-mail: sychenxiang@126.com [Sanmen People' s Hospital of Zhejiang, Sanmen, Zhejiang, 317100 (China)

2015-08-21

As the ribonucleotide reductase small subunit, the high expression of ribonucleotide reductase small subunit M2 (RRM2) induces cancer and contributes to tumor growth and invasion. In several colorectal cancer (CRC) cell lines, we found that the expression levels of RRM2 were closely related to the transcription factor E2F1. Mechanistic studies were conducted to determine the molecular basis. Ectopic overexpression of E2F1 promoted RRM2 transactivation while knockdown of E2F1 reduced the levels of RRM2 mRNA and protein. To further investigate the roles of RRM2 which was activated by E2F1 in CRC, CCK-8 assay and EdU incorporation assay were performed. Overexpression of E2F1 promoted cell proliferation in CRC cells, which was blocked by RRM2 knockdown attenuation. In the migration and invasion tests, overexpression of E2F1 enhanced the migration and invasion of CRC cells which was abrogated by silencing RRM2. Besides, overexpression of RRM2 reversed the effects of E2F1 knockdown partially in CRC cells. Examination of clinical CRC specimens demonstrated that both RRM2 and E2F1 were elevated in most cancer tissues compared to the paired normal tissues. Further analysis showed that the protein expression levels of E2F1 and RRM2 were parallel with each other and positively correlated with lymph node metastasis (LNM), TNM stage and distant metastasis. Consistently, the patients with low E2F1 and RRM2 levels have a better prognosis than those with high levels. Therefore, we suggest that E2F1 can promote CRC proliferation, migration, invasion and metastasis by regulating RRM2 transactivation. Understanding the role of E2F1 in activating RRM2 transcription will help to explain the relationship between E2F1 and RRM2 in CRC and provide a novel predictive marker for diagnosis and prognosis of the disease. - Highlights: • E2F1 promotes RRM2 transactivation in CRC cells. • E2F1 promotes the proliferation of CRC cells by activating RRM2. • E2F1 promotes the migration and

Overexpression of heterogeneous nuclear ribonucleoprotein F stimulates renal Ace-2 gene expression and prevents TGF-β1-induced kidney injury in a mouse model of diabetes.

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Lo, Chao-Sheng; Shi, Yixuan; Chang, Shiao-Ying; Abdo, Shaaban; Chenier, Isabelle; Filep, Janos G; Ingelfinger, Julie R; Zhang, Shao-Ling; Chan, John S D

2015-10-01

We investigated whether heterogeneous nuclear ribonucleoprotein F (hnRNP F) stimulates renal ACE-2 expression and prevents TGF-β1 signalling, TGF-β1 inhibition of Ace-2 gene expression and induction of tubulo-fibrosis in an Akita mouse model of type 1 diabetes. Adult male Akita transgenic (Tg) mice overexpressing specifically hnRNP F in their renal proximal tubular cells (RPTCs) were studied. Non-Akita littermates and Akita mice served as controls. Immortalised rat RPTCs stably transfected with plasmid containing either rat Hnrnpf cDNA or rat Ace-2 gene promoter were also studied. Overexpression of hnRNP F attenuated systemic hypertension, glomerular filtration rate, albumin/creatinine ratio, urinary angiotensinogen (AGT) and angiotensin (Ang) II levels, renal fibrosis and profibrotic gene (Agt, Tgf-β1, TGF-β receptor II [Tgf-βrII]) expression, stimulated anti-profibrotic gene (Ace-2 and Ang 1-7 receptor [MasR]) expression, and normalised urinary Ang 1-7 level in Akita Hnrnpf-Tg mice as compared with Akita mice. In vitro, hnRNP F overexpression stimulated Ace-2 gene promoter activity, mRNA and protein expression, and attenuated Agt, Tgf-β1 and Tgf-βrII gene expression. Furthermore, hnRNP F overexpression prevented TGF-β1 signalling and TGF-β1 inhibition of Ace-2 gene expression. These data demonstrate that hnRNP F stimulates Ace-2 gene transcription, prevents TGF-β1 inhibition of Ace-2 gene transcription and induction of kidney injury in diabetes. HnRNP F may be a potential target for treating hypertension and renal fibrosis in diabetes.

The functioning of the reactors G2-G3 at Marcoule and E.D.F. 1; Experience de fonctionnement des reacteurs G2-G3 de Marcoule et enseignements des essais de demarrage du reacteur E.D.F. 1 de Chinon

Energy Technology Data Exchange (ETDEWEB)

Boussard, R; Conte, F [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires; Stolz, J M [Electricite de France (EDF), 75 - Paris (France)

1964-07-01

After resuming briefly the characteristics of the installations G2-G3 at Marcoule and EDF 1 at Chinon, the authors review the main aspects of the tests, the starting and the exploitation of these reactors. Among the various points examined, particular emphasis is given to the devices of original nature such as tubular fuel elements, flattening of the neutron flux by stuffing, behaviour of the reactor tanks and the cooling circuits, the blowers, unloading devices, regulation and functioning of the informations. This analysis deals equally with the performances obtained and the difficulties and the various incidents experienced during the initial starting period. Among the more interesting results, the progressive increase in the power of the Marcoule reactors is mentioned, obtained through a better knowledge of the parameters covering the functioning of the reactors such as the distribution of the flux and the temperatures etc... acquired during the course of the exploitation of the reactor. The conclusion reached by the authors is that the experience gained on these installations has shown: - that during an initial period, adjustments became necessary, all of which turned out to be possible, - that an analysis of their functioning has permitted the progressive movement towards a truly industrial exploitation. (authors) [French] Les auteurs, apres un bref rappel des caracteristiques des installations G2 - G3 de MARCOULE et E.D.F. 1 de CHINON, passent en revue les principaux aspects des essais, de la mise en service et de l'exploitation de ces centrales. Parmi les divers points examines, une attention speciale est accordee aux dispositifs presentant un caractere original tels que elements combustibles tubulaires, aplatissement du flux neutronique par gavage, comportement des caissons des reacteurs et des circuits de refroidissement, soufflantes, appareils de dechargement, regulation et fonctionnement des informations. L'analyse presentee porte tant sur les

Differential expression of members of the E2F family of transcription factors in rodent testes

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Toppari Jorma

2006-12-01

Full Text Available Abstract Background The E2F family of transcription factors is required for the activation or repression of differentially expressed gene programs during the cell cycle in normal and abnormal development of tissues. We previously determined that members of the retinoblastoma protein family that interacts with the E2F family are differentially expressed and localized in almost all the different cell types and tissues of the testis and in response to known endocrine disruptors. In this study, the cell-specific and stage-specific expression of members of the E2F proteins has been elucidated. Methods We used immunohistochemical (IHC analysis of tissue sections and Western blot analysis of proteins, from whole testis and microdissected stages of seminiferous tubules to study the differential expression of the E2F proteins. Results For most of the five E2F family members studied, the localizations appear conserved in the two most commonly studied rodent models, mice and rats, with some notable differences. Comparisons between wild type and E2F-1 knockout mice revealed that the level of E2F-1 protein is stage-specific and most abundant in leptotene to early pachytene spermatocytes of stages IX to XI of mouse while strong staining of E2F-1 in some cells close to the basal lamina of rat tubules suggest that it may also be expressed in undifferentiated spermatogonia. The age-dependent development of a Sertoli-cell-only phenotype in seminiferous tubules of E2F-1 knockout males corroborates this, and indicates that E2F-1 is required for spermatogonial stem cell renewal. Interestingly, E2F-3 appears in both terminally differentiated Sertoli cells, as well as spermatogonial cells in the differentiative pathway, while the remaining member of the activating E2Fs, E2F-2 is most concentrated in spermatocytes of mid to late prophase of meiosis. Comparisons between wildtype and E2F-4 knockout mice demonstrated that the level of E2F-4 protein displays a distinct

Comportamiento Mecánico Estático de los Instrumentos S1, S2, F1 de Protaper Universal® Bajo Torsión y Doblamiento. Análisis por Elementos Finitos

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Luisa Fernanda Cartagena

2011-10-01

Full Text Available Propósito: Examinar el comportamiento mecánico estático de los instrumentos ProTaper Universal® S1, S2, F1 bajo torsión y doblamiento teniendo en cuenta las propiedades mecánicas del material, mediante el método de elementos finitos. Metodología: Estudio Observacional descriptivo. Las limas investigadas fueron S1, S2, F1 de ProTaper Universal®, modeladas con el software ANSYS 10 y sometidas a fuerzas de torsión empezando en 0.25N/cm hasta alcanzar el torque máximo recomendado por la casa comercial Maillefer® y doblamiento en un ángulo de 600. Resultados:El máximo esfuerzo ocurre en el núcleo de la sección para todos los instrumentos evaluados;  al incrementar el torque el  esfuerzo  se disipa a la periferia para S1 (D5, D10, D14, S2 (D5, D7, D8, D10, F1 (D2, D3, D5.  La lima S1 al ser sometida a  torsión en D0 y D5 independiente del torque que fuese aplicado el máximo de esfuerzo superaba el límite de deformación plástica en el núcleo de la sección  del instrumento. La lima S2 con torques de  1 ó 1,5 N/cm superó  el límite elástico del material. Lima F1 en D0, D2 con torques de  0.25, 0.5, 1, 1.5, 2 N/cm el esfuerzo máximo no supero el límite de deformación plástica. En la prueba de doblamiento la gran mayoría de la estructura de las limas S1, S2, F1, se encuentra  por debajo del esfuerzo de ruptura (línea neutral es bastante ancha.Conclusion: Las fuerzas de  torsión para todas la limas del estudio mostraron tener mayor riesgo de separación del instrumento en comparación con  las fuerzas de doblamiento. 

The FasX Small Regulatory RNA Negatively Regulates the Expression of Two Fibronectin-Binding Proteins in Group A Streptococcus.

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Danger, Jessica L; Makthal, Nishanth; Kumaraswami, Muthiah; Sumby, Paul

2015-12-01

The group A Streptococcus (GAS; Streptococcus pyogenes) causes more than 700 million human infections each year. The success of this pathogen can be traced in part to the extensive arsenal of virulence factors that are available for expression in temporally and spatially specific manners. To modify the expression of these virulence factors, GAS use both protein- and RNA-based regulators, with the best-characterized RNA-based regulator being the small regulatory RNA (sRNA) FasX. FasX is a 205-nucleotide sRNA that contributes to GAS virulence by enhancing the expression of the thrombolytic secreted virulence factor streptokinase and by repressing the expression of the collagen-binding cell surface pili. Here, we have expanded the FasX regulon, showing that this sRNA also negatively regulates the expression of the adhesion- and internalization-promoting, fibronectin-binding proteins PrtF1 and PrtF2. FasX posttranscriptionally regulates the expression of PrtF1/2 through a mechanism that involves base pairing to the prtF1 and prtF2 mRNAs within their 5' untranslated regions, overlapping the mRNA ribosome-binding sites. Thus, duplex formation between FasX and the prtF1 and prtF2 mRNAs blocks ribosome access, leading to an inhibition of mRNA translation. Given that FasX positively regulates the expression of the spreading factor streptokinase and negatively regulates the expression of the collagen-binding pili and of the fibronectin-binding PrtF1/2, our data are consistent with FasX functioning as a molecular switch that governs the transition of GAS between the colonization and dissemination stages of infection. More than half a million deaths each year are a consequence of infections caused by GAS. Insights into how this pathogen regulates the production of proteins during infection may facilitate the development of novel therapeutic or preventative regimens aimed at inhibiting this activity. Here, we have expanded insight into the regulatory activity of the GAS small

Characterization of E2F8, a novel E2F-like cell-cycle regulated repressor of E2F-activated transcription

DEFF Research Database (Denmark)

Christensen, Jesper; Cloos, Paul; Toftegaard, Ulla

2005-01-01

The E2F family of transcription factors are downstream effectors of the retinoblastoma protein, pRB, pathway and are essential for the timely regulation of genes necessary for cell-cycle progression. Here we describe the characterization of human and murine E2F8, a new member of the E2F family...

TaPP2C1, a Group F2 Protein Phosphatase 2C Gene, Confers Resistance to Salt Stress in Transgenic Tobacco.

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Wei Hu

Full Text Available Group A protein phosphatases 2Cs (PP2Cs are essential components of abscisic acid (ABA signaling in Arabidopsis; however, the function of group F2 subfamily PP2Cs is currently less known. In this study, TaPP2C1 which belongs to group F2 was isolated and characterized from wheat. Expression of the TaPP2C1-GFP fusion protein suggested its ubiquitous localization within a cell. TaPP2C1 expression was downregulated by abscisic acid (ABA and NaCl treatments, but upregulated by H2O2 treatment. Overexpression of TaPP2C1 in tobacco resulted in reduced ABA sensitivity and increased salt resistance of transgenic seedlings. Additionally, physiological analyses showed that improved resistance to salt stress conferred by TaPP2C1 is due to the reduced reactive oxygen species (ROS accumulation, the improved antioxidant system, and the increased transcription of genes in the ABA-independent pathway. Finally, transgenic tobacco showed increased resistance to oxidative stress by maintaining a more effective antioxidant system. Taken together, these results demonstrated that TaPP2C1 negatively regulates ABA signaling, but positively regulates salt resistance. TaPP2C1 confers salt resistance through activating the antioxidant system and ABA-independent gene transcription process.

Up-regulated MicroRNA-181a induces carcinogenesis in Hepatitis B virus-related hepatocellular carcinoma by targeting E2F5

International Nuclear Information System (INIS)

Zou, Chengcheng; Li, Yongguo; Cao, Yiyi; Zhang, Jinnan; Jiang, Jingrong; Sheng, Yanrui; Wang, Sen; Huang, Ailong; Tang, Hua

2014-01-01

Accumulating evidence showed that microRNAs are involved in development and progression of multiple tumors. Recent studies have found that miR-181a were dysregulated in several types of cancers, however, the function of miR-181a in hepatocellular carcinoma (HCC) remains unclear. In this study we assessed the potential association between miR-181a, HBV and HCC. The expression of miR-181a in HBV-expressing cells was determined by using qRT-PCR. Dual-Luciferase reporter Assay, qRT-PCR and western blot were performed to investigate the target genes of miR-181a. The effects of miR-181a on HCC proliferation were analyzed by MTS and colony formation assay. Tumor growth assay was used to analyze the effect of miR-181a on tumor formation. HBV up-regulated miR-181a expression by enhancing its promoter activity. Overexpression of miR-181a in hepatoma cells promoted cell growth in vitro and tumor formation in vivo. Conversely, inhibition of miR-181a suppressed the proliferation of HBV-expressing cells. Mechanism investigation revealed that miR-181a inhibited the expression of transcription factor E2F5 by specifically targeting its mRNA 3′UTR. Moreover, E2F5 inhibition induced cell growth and rescued the suppressive effect of miR-181a inhibitor on the proliferation of SMMC-7721 cells. Interestingly, we also discovered that HBV could down-regulate E2F5 expression. Those results strongly suggested that HBV down-regulated E2F5 expression, in part, by up-regulating the expression of miR-181a. Up-regulation of miR-181a by HBV in hepatoma cells may contribute to the progression of HCC possibly by targeting E2F5, suggesting miR-181a plays important role in HCC development

Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells

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Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao [Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

2016-08-05

The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4–5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba{sup 2+}-sensitive inward rectifier K{sup +} current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca{sup 2+} imaging study revealed that the hypoxic stress enhanced store-operated Ca{sup 2+} (SOC) entry, which was significantly reduced in the presence of 100 μM Ba{sup 2+}. On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba{sup 2+}. We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca{sup 2+} entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. -- Highlights: •Hypoxic culture of brain endothelial cells (BEC) caused membrane hyperpolarization. •This hyperpolarization was due to the increased expression of Kir2.1 channels. •Hypoxia enhanced store-operated Ca{sup 2+} (SOC) entry via Kir2.1 up-regulation. •Expression levels of putative SOC

Up-regulation of intestinal epithelial cell derived IL-7 expression by keratinocyte growth factor through STAT1/IRF-1, IRF-2 pathway.

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Yu-Jiao Cai

Full Text Available BACKGROUND: Epithelial cells(EC-derived interleukin-7 (IL-7 plays a crucial role in control of development and homeostasis of neighboring intraepithelial lymphocytes (IEL, and keratinocyte growth factor (KGF exerts protective effects on intestinal epithelial cells and up-regulates EC-derived IL-7 expression through KGFR pathway. This study was to further investigate the molecular mechanism involved in the regulation of IL-7 expression by KGF in the intestine. METHODS: Intestinal epithelial cells (LoVo cells and adult C57BL/6J mice were treated with KGF. Epithelial cell proliferation was studied by flow cytometry for BrdU-incorporation and by immunohistochemistry for PCNA staining. Western blot was used to detect the changes of expression of P-Tyr-STAT1, STAT1, and IL-7 by inhibiting STAT1. Alterations of nuclear extracts and total proteins of IRF-1, IRF-2 and IL-7 following IRF-1 and IRF-2 RNA interference with KGF treatment were also measured with western blot. Moreover, IL-7 mRNA expressions were also detected by Real-time PCR and IL-7 protein level in culture supernatants was measured by enzyme linked immunosorbent assay(ELISA. RESULTS: KGF administration significantly increased LoVo cell proliferation and also increased intestinal wet weight, villus height, crypt depth and crypt cell proliferation in mice. KGF treatment led to increased levels of P-Tyr-STAT1, RAPA and AG490 both blocked P-Tyr-STAT1 and IL-7 expression in LoVo cells. IRF-1 and IRF-2 expression in vivo and in vitro were also up-regulated by KGF, and IL-7 expression was decreased after IRF-1 and IRF-2 expression was silenced by interfering RNA, respectively. CONCLUSION: KGF could up-regulate IL-7 expression through the STAT1/IRF-1, IRF-2 signaling pathway, which is a new insight in potential effects of KGF on the intestinal mucosal immune system.

Expression of the nuclear gene TaF(A)d is under mitochondrial retrograde regulation in anthers of male sterile wheat plants with timopheevii cytoplasm.

Science.gov (United States)

Xu, Pei; Yang, Yuwen; Zhang, Zhengzhi; Chen, Weihua; Zhang, Caiqin; Zhang, Lixia; Zou, Sixiang; Ma, Zhengqiang

2008-01-01

Alterations of mitochondrial-encoded subunits of the F(o)F(1)-ATP synthase are frequently associated with cytoplasmic male sterility (CMS) in plants; however, little is known about the relationship of the nuclear encoded subunits of this enzyme with CMS. In the present study, the full cDNA of the gene TaF(A)d that encodes the putative F(A)d subunit of the F(o)F(1)-ATP synthase was isolated from the wheat (Triticum aestivum) fertility restorer '2114' for timopheevii cytoplasm-based CMS. The deduced 238 amino acid polypeptide is highly similar to its counterparts in dicots and other monocots but has low homology to its mammalian equivalents. TaF(A)d is a single copy gene in wheat and maps to the short arm of the group 6 chromosomes. Transient expression of the TaF(A)d-GFP fusion in onion epidermal cells demonstrated TaF(A)d's mitochondrial location. TaF(A)d was expressed abundantly in stem, leaf, anther, and ovary tissues of 2114. Nevertheless, its expression was repressed in anthers of CMS plants with timopheevii cytoplasm. Genic male sterility did not affect its expression in anthers. The expression of the nuclear gene encoding the 20 kDa subunit of F(o) was down-regulated in a manner similar to TaF(A)d in the T-CMS anthers while that of genes encoding the 6 kDa subunit of F(o) and the gamma subunit of F(1) was unaffected. These observations implied that TaF(A)d is under mitochondrial retrograde regulation in the anthers of CMS plants with timopheevii cytoplasm.

Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses

International Nuclear Information System (INIS)

Fukuyama, Yoshiko; Tokuhara, Daisuke; Sekine, Shinichi; Kataoka, Kosuke; Markham, Jonathan D.; Irwin, Allyson R.; Moon, Grace H.; Tokuhara, Yuka; Fujihashi, Keiko; Davydova, Julia; Yamamoto, Masato; Gilbert, Rebekah S.; Fujihashi, Kohtaro

2012-01-01

Highlights: ► Nasal Ad-FL effectively up-regulates APC function by CD11c + DCs in mucosal tissues. ► Nasal Ad-FL induces Notch ligand (L)-expressing CD11c + DCs. ► Notch L-expressing DCs support the induction of Th1- and Th2-type cytokine responses. -- Abstract: Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c + dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c + DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c + DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c + DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4 + T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-γ, IL-2 and IL-4 producing CD4 + T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch–Notch-L pathway. These results show that Ad-FL induces CD11c + DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

Gene expression profiling following NRF2 and KEAP1 siRNA knockdown in human lung fibroblasts identifies CCL11/Eotaxin-1 as a novel NRF2 regulated gene

Science.gov (United States)

2012-01-01

Background Oxidative Stress contributes to the pathogenesis of many diseases. The NRF2/KEAP1 axis is a key transcriptional regulator of the anti-oxidant response in cells. Nrf2 knockout mice have implicated this pathway in regulating inflammatory airway diseases such as asthma and COPD. To better understand the role the NRF2 pathway has on respiratory disease we have taken a novel approach to define NRF2 dependent gene expression in a relevant lung system. Methods Normal human lung fibroblasts were transfected with siRNA specific for NRF2 or KEAP1. Gene expression changes were measured at 30 and 48 hours using a custom Affymetrix Gene array. Changes in Eotaxin-1 gene expression and protein secretion were further measured under various inflammatory conditions with siRNAs and pharmacological tools. Results An anti-correlated gene set (inversely regulated by NRF2 and KEAP1 RNAi) that reflects specific NRF2 regulated genes was identified. Gene annotations show that NRF2-mediated oxidative stress response is the most significantly regulated pathway, followed by heme metabolism, metabolism of xenobiotics by Cytochrome P450 and O-glycan biosynthesis. Unexpectedly the key eosinophil chemokine Eotaxin-1/CCL11 was found to be up-regulated when NRF2 was inhibited and down-regulated when KEAP1 was inhibited. This transcriptional regulation leads to modulation of Eotaxin-1 secretion from human lung fibroblasts under basal and inflammatory conditions, and is specific to Eotaxin-1 as NRF2 or KEAP1 knockdown had no effect on the secretion of a set of other chemokines and cytokines. Furthermore, the known NRF2 small molecule activators CDDO and Sulphoraphane can also dose dependently inhibit Eotaxin-1 release from human lung fibroblasts. Conclusions These data uncover a previously unknown role for NRF2 in regulating Eotaxin-1 expression and further the mechanistic understanding of this pathway in modulating inflammatory lung disease. PMID:23061798

N-MYC down-regulated-like proteins regulate meristem initiation by modulating auxin transport and MAX2 expression.

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Mudgil, Yashwanti; Ghawana, Sanjay; Jones, Alan M

2013-01-01

N-MYC down-regulated-like (NDL) proteins interact with the Gβ subunit (AGB1) of the heterotrimeric G protein complex and play an important role in AGB1-dependent regulation of lateral root formation by affecting root auxin transport, auxin gradients and the steady-state levels of mRNA encoding the PIN-FORMED 2 and AUXIN 1 auxin transport facilitators. Auxin transport in aerial tissue follows different paths and utilizes different transporters than in roots; therefore, in the present study, we analyzed whether NDL proteins play an important role in AGB1-dependent, auxin-mediated meristem development. Expression levels of NDL gene family members need to be tightly regulated, and altered expression (both over-expression and down-regulation) confers ectopic growth. Over-expression of NDL1 disrupts vegetative and reproductive organ development. Reduced expression of the NDL gene family members results in asymmetric leaf emergence, twinning of rosette leaves, defects in leaf formation, and abnormal silique distribution. Reduced expression of the NDL genes in the agb1-2 (null allele) mutant rescues some of the abnormal phenotypes, such as silique morphology, silique distribution, and peduncle angle, suggesting that proper levels of NDL proteins are maintained by AGB1. We found that all of these abnormal aerial phenotypes due to altered NDL expression were associated with increases in basipetal auxin transport, altered auxin maxima and altered MAX2 expression within the inflorescence stem. NDL proteins, together with AGB1, act as positive regulators of meristem initiation and branching. AGB1 and NDL1 positively regulate basipetal inflorescence auxin transport and modulate MAX2 expression in shoots, which in turn regulates organ and lateral meristem formation by the establishment and maintenance of auxin gradients.

N-MYC down-regulated-like proteins regulate meristem initiation by modulating auxin transport and MAX2 expression.

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Yashwanti Mudgil

Full Text Available N-MYC down-regulated-like (NDL proteins interact with the Gβ subunit (AGB1 of the heterotrimeric G protein complex and play an important role in AGB1-dependent regulation of lateral root formation by affecting root auxin transport, auxin gradients and the steady-state levels of mRNA encoding the PIN-FORMED 2 and AUXIN 1 auxin transport facilitators. Auxin transport in aerial tissue follows different paths and utilizes different transporters than in roots; therefore, in the present study, we analyzed whether NDL proteins play an important role in AGB1-dependent, auxin-mediated meristem development.Expression levels of NDL gene family members need to be tightly regulated, and altered expression (both over-expression and down-regulation confers ectopic growth. Over-expression of NDL1 disrupts vegetative and reproductive organ development. Reduced expression of the NDL gene family members results in asymmetric leaf emergence, twinning of rosette leaves, defects in leaf formation, and abnormal silique distribution. Reduced expression of the NDL genes in the agb1-2 (null allele mutant rescues some of the abnormal phenotypes, such as silique morphology, silique distribution, and peduncle angle, suggesting that proper levels of NDL proteins are maintained by AGB1. We found that all of these abnormal aerial phenotypes due to altered NDL expression were associated with increases in basipetal auxin transport, altered auxin maxima and altered MAX2 expression within the inflorescence stem.NDL proteins, together with AGB1, act as positive regulators of meristem initiation and branching. AGB1 and NDL1 positively regulate basipetal inflorescence auxin transport and modulate MAX2 expression in shoots, which in turn regulates organ and lateral meristem formation by the establishment and maintenance of auxin gradients.

Influencia del CaF2 sobre la capacidad de reacción de crudos de cemento

OpenAIRE

Palomo, Ángel; Blanco, M. Teresa

1982-01-01

En este trabajo se estudia el efecto de una pequeña cantidad de CaF2 sobre la capacidad de reacción de crudos de cemento, para lo cual se comparan los comportamientos térmicos en función del tiempo de clinkerización de un crudo comercial con y sin adición de CaF2. Se da una estimación de los tiempos necesarios para completar las reacciones a diferentes temperaturas. El efecto mineralizador del espato-fluor pasa por un máximo a temperaturas de clinkerización del orden de 1.200ºC y tiempos d...

Comparative analysis of B7-1 and B7-2 expression in Langerhans cells: differential regulation by T helper type 1 and T helper type 2 cytokines.

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Kawamura, T; Furue, M

1995-07-01

Epidermal Langerhans cells (LC) are Ia-bearing potent antigen-presenting cells (APC) of dendritic cell lineage that play a crucial role in primary and secondary T cell-dependent immune responses. LC express several costimulatory molecules such as B7, which has been implicated as one of the important determinants of professional APC. Recently, B7 antigens have been shown to include three distinct molecules termed B7-1, B7-2, and B7-3, and the expression of B7-1 and B7-2 in LC has been already confirmed. However, little is known of the regulation of B7-1 and B7-2 expression in LC. We demonstrated that LC do not express B7-1 and B7-2 in situ; however, the expression of both molecules is rapidly induced during the first 3 days of culture, and high levels of expression are maintained at least until day 6. We show that the expression of B7-2 in LC is much higher than that of B7-1 in each experiment, and that B7-1 and B7-2 expression is reproducibly augmented by interleukin (IL)-4 in a dose-dependent manner; however, IL-2 affected expression very little. Finally, B7-1 expression is significantly and dose-dependently down-regulated by interferon (IFN)-gamma or IL-10, and B7-2 expression is consistently inhibited by IL-10, but not by IFN-gamma. The effects of these cytokines are active only in the induction phase (during first 3 days of culture) of B7 expression: the modulatory effects of cytokines are hardly detected in the plateau phase (days 4 to 6 of culture) of B7 expression in LC. These findings suggest that B7-1 and B7-2 expression are indeed selectively and differentially regulated by these T cell-derived cytokines, and that the cytokines may modulate the synthesis of B7 molecules rather than the degradation of already-expressed B7 molecules.

Influenza virus PB1-F2 protein induces cell death through mitochondrial ANT3 and VDAC1.

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Dmitriy Zamarin

2005-09-01

Full Text Available The influenza virus PB1-F2 is an 87-amino acid mitochondrial protein that previously has been shown to induce cell death, although the mechanism of apoptosis induction has remained unclear. In the process of characterizing its mechanism of action we found that the viral PB1-F2 protein sensitizes cells to apoptotic stimuli such as tumor necrosis factor alpha, as demonstrated by increased cleavage of caspase 3 substrates in PB1-F2-expressing cells. Moreover, treatment of purified mouse liver mitochondria with recombinant PB1-F2 protein resulted in cytochrome c release, loss of the mitochondrial membrane potential, and enhancement of tBid-induced mitochondrial permeabilization, suggesting a possible mechanism for the observed cellular sensitization to apoptosis. Using glutathione-S-transferase pulldowns with subsequent mass spectrometric analysis, we identified the mitochondrial interactors of the PB1-F2 protein and showed that the viral protein uniquely interacts with the inner mitochondrial membrane adenine nucleotide translocator 3 and the outer mitochondrial membrane voltage-dependent anion channel 1, both of which are implicated in the mitochondrial permeability transition during apoptosis. Consistent with this interaction, blockers of the permeability transition pore complex (PTPC inhibited PB1-F2-induced mitochondrial permeabilization. Based on our findings, we propose a model whereby the proapoptotic PB1-F2 protein acts through the mitochondrial PTPC and may play a role in the down-regulation of the host immune response to infection.

E2Fs regulate the expression of genes involved in differentiation, development, proliferation, and apoptosis

DEFF Research Database (Denmark)

Müller, H; Bracken, A P; Vernell, R

2001-01-01

The retinoblastoma protein (pRB) and its two relatives, p107 and p130, regulate development and cell proliferation in part by inhibiting the activity of E2F-regulated promoters. We have used high-density oligonucleotide arrays to identify genes in which expression changed in response to activation...

The silkworm Bombyx mori cuticular protein CPR55 gene is regulated by the transcription factor βFTZ-F1

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Md. Saheb Ali

2016-01-01

Full Text Available The insect cuticle is composed of various proteins and formed during the moult under a complex biological process that depends on the cross talk between hormone levels and gene expression. In the present study, we aimed to clarify the ecdysone-dependent temporal regulation mechanisms of cuticular proteins expression and the underlying control of Bombyx mori metamorphosis. The expression of CPR55 was observed from the W3 early stage and peaked at pupation when the ecdysteroid titre declined. CPR55 was induced by the ecdysone pulse, and their expression peaked at 24 h after transfer to a hormone free medium. Transcripts of CPR55 were neither observed after the 20E pulse treatment in the presence of cycloheximide nor after the addition of 20E in V4 wing discs. We analysed the upstream region of the CPR55 gene using a transient reporter assay with a gene gun system which identified only one βFTZ-F1 binding site important for cis-acting elements for the transcription activation of the luciferase reporter gene by an ecdysone pulse. Site-directed mutagenesis of this element in the context of the 589-bp promoter fragment drastically decreased the reporter activity. The nuclear protein bound to βFTZ-F1 sites was identified by an electrophoretic mobility shift assay suggesting that CPR55 expression was regulated by βFTZ-F1 through the ecdysone pulse. The results confirmed that transcription factor, BmβFTZ-F1, binds to the cis-regulatory elements in the promoter of the gene coding for cuticle protein, CPR55, and regulates its expression during B. mori metamorphosis.

Nicotine-Mediated Regulation of Nicotinic Acetylcholine Receptors in Non-Small Cell Lung Adenocarcinoma by E2F1 and STAT1 Transcription Factors.

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Courtney Schaal

Full Text Available Cigarette smoking is the major risk factor for non-small cell lung cancer (NSCLC, which accounts for 80% of all lung cancers. Nicotine, the addictive component of tobacco smoke, can induce proliferation, migration, invasion, epithelial-mesenchymal transition (EMT, angiogenesis, and survival in NSCLC cell lines, as well as growth and metastasis of NSCLC in mice. This nicotine-mediated tumor progression is facilitated through activation of nicotinic acetylcholine receptors (nAChRs, specifically the α7 subunit; however, how the α7 nAChR gene is regulated in lung adenocarcinoma is not fully clear. Here we demonstrate that the α7 nAChR gene promoter is differentially regulated by E2F and STAT transcription factors through a competitive interplay; E2F1 induces the promoter, while STAT transcription factors repress it by binding to an overlapping site at a region -294 through -463bp upstream of the transcription start site. Treatment of cells with nicotine induced the mRNA and protein levels of α7 nAChR; this could be abrogated by treatment with inhibitors targeting Src, PI3K, MEK, α7 nAChR, CDK4/6 or a disruptor of the Rb-Raf-1 interaction. Further, nicotine-mediated induction of α7 nAChR was reduced when E2F1 was depleted and in contrast elevated when STAT1 was depleted by siRNAs. Interestingly, extracts from e-cigarettes, which have recently emerged as healthier alternatives to traditional cigarette smoking, can also induce α7 nAChR expression in a manner similar to nicotine. These results suggest an autoregulatory feed-forward loop that induces the levels of α7 nAChR upon exposure to nicotine, which enhances the strength of the signal. It can be imagined that such an induction of α7 nAChR contributes to the tumor-promoting functions of nicotine.

Steroidal regulation of Ihh and Gli1 expression in the rat uterus.

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

2010-05-01

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

Regulation of hepatic PPARγ2 and lipogenic gene expression by melanocortin

International Nuclear Information System (INIS)

Poritsanos, Nicole J.; Wong, Davie; Vrontakis, Maria E.; Mizuno, Tooru M.

2008-01-01

The central melanocortin system regulates hepatic lipid metabolism. Hepatic lipogenic gene expression is regulated by transcription factors including sterol regulatory element-binding protein 1c (SREBP-1c), carbohydrate responsive element-binding protein (ChREBP), and peroxisome proliferator-activated receptor γ2 (PPARγ2). However, it is unclear if central melanocortin signaling regulates hepatic lipogenic gene expression through the activation of these transcription factors. To delineate the molecular mechanisms by which the melanocortin system regulates hepatic lipid metabolism, we examined the effect of intracerebroventricular injection of SHU9119, a melanocortin receptor antagonist, on hepatic expression levels of genes involved in lipid metabolism in mice. SHU9119 treatment increased hepatic triglyceride content and mRNA levels of lipogenic genes, SREBP-1c, and PPARγ2, whereas it did not cause any changes in hepatic ChREBP mRNA levels. These findings suggest that reduced central melanocortin signaling increases hepatic lipid deposition by stimulating hepatic lipogenic gene expression at least partly through the activation of SREBP-1c and PPARγ2

miR-335 negatively regulates osteosarcoma stem cell-like properties by targeting POU5F1.

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Guo, Xiaodong; Yu, Ling; Zhang, Zhengpei; Dai, Guo; Gao, Tian; Guo, Weichun

2017-01-01

Evidence is accumulating to link cancer stem cells to the pathogenesis and progression of osteosarcoma. The aim of this study is to investigate the role of miR-335 in osteosarcoma stem cells. Tumor spheroid culture and flow cytometry were applied to screen out osteosarcoma stem cells. Real-time quantitative PCR was used to detect the expression level of miR-335 in MG63, U2OS and 143B osteosarcoma stem cells. The relationship of miR-335 expression with osteosarcoma stem cells was then analyzed. Transwell assay and transplantation assay were performed to elucidate biological effects of miR-335 on cell invasion and vivo tumor formation. Western Blot and luciferase assays were executed to investigate the regulation of POU5F1 by miR-335. The expression of miR-335 in osteosarcoma stem cells was lower than their differentiated counterparts. Cells expressing miR-335 possessed decreased stem cell-like properties. Gain or loss of function assays were applied to find that miR-335 antagonist promoted stem cell-like properties as well as invasion. Luciferase report and transfection assay showed that POU5F1 was downregulated by miR-335. Pre-miR-335 resulted in tumor enhanced sensitivity to traditional chemotherapy, whereas anti-miR-335 promoted chemoresistance. Finally, the inhibitory effect of miR-335 on in vivo tumor formation showed that combination of pre-miR-335 with cisplatin further reduced the tumor size, and miR-335 brought down the sphere formation capacity induced by cisplatin. The current study demonstrates that miR-335 negatively regulates osteosarcoma stem cell-like properties by targeting POU5F1, and miR-335 could target CSCs to synergize with traditional chemotherapeutic agents to overcome osteosarcoma.

In vivo evaluation of 2'-deoxy-2'-[{sup 18}F]fluoro-5-iodo-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]FIAU) and 2'-deoxy-2'-[{sup 18}F]fluoro-5-ethyl-1-{beta}-D-arabinofuranosyluracil ([{sup 18}F]FEAU) as markers for suicide gene expression

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Alauddin, Mian M. [University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd. T8.3895, P.O. Box 059, Houston, TX (United States); Shahinian, Antranic; Park, Ryan; Fissekis, John D.; Conti, Peter S. [University of Southern California, PET Imaging Science Center, Keck School of Medicine, Los Angeles, CA (United States); Tohme, Michel [University of Southern California, PET Imaging Science Center, Keck School of Medicine, Los Angeles, CA (United States); Department of Biomedical Engineering, UC Davis, Davis, CA (United States)

2007-06-15

FIAU and FEAU were evaluated in vitro and in vivo as markers for HSV1-tk gene expression. In vitro and biodistribution studies were performed in wild type and transduced HT-29 cells using [{sup 14}C]FIAU and [{sup 3}H]FEAU. PET imaging was performed using [{sup 18}F]FIAU and [{sup 18}F]FEAU. In vitro uptake of [{sup 14}C]FIAU in tk-positive cells was 39-fold, 49-fold, and 43-fold higher (p < 0.001) than in wild type cells at 30, 60, and 120 min, respectively. Uptake of [{sup 3}H]FEAU in transduced cells was 46-fold, 62-fold, and 121-fold higher (p < 0.001) than in wild type cells at the same time points. In vivo uptake of [{sup 14}C]FIAU at 2 h in HSV1-tk positive tumors was 15.48 {+-} 3.94, 6.7-fold higher (p < 0.001) than in wild type tumors. Uptake of [{sup 3}H]FEAU in transduced tumors was 9.98 {+-} 1.99, 5.0-fold higher (p < 0.001) than in wild type tumors. Micro-PET images using [{sup 18}F]FIAU and [{sup 18}F]FEAU also showed very high uptake in HSV-tk tumors. [{sup 18}F]FIAU and [{sup 18}F]FEAU appear to be potential PET imaging agents for gene expression. (orig.)

MicroRNA-101 negatively regulates Ezh2 and its expression is modulated by androgen receptor and HIF-1α/HIF-1β

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Xu Jianfeng

2010-05-01

Full Text Available Abstract Background In prostate cancer (PCa, the common treatment involving androgen ablation alleviates the disease temporarily, but results in the recurrence of highly aggressive and androgen-independent metastatic cancer. Therefore, more effective therapeutic approaches are needed. It is known that aberrant epigenetics contributes to prostate malignancy. Unlike genetic changes, these epigenetic alterations are reversible, which makes them attractive targets in PCa therapy to impede cancer progression. As a histone methyltransferease, Ezh2 plays an essential role in epigenetic regulation. Since Ezh2 is overexpressed and acts as an oncogene in PCa, it has been proposed as a bona fide target of PCa therapy. MicroRNAs (miRNAs regulate gene expression through modulating protein translation. Recently, the contribution of miRNAs in cancer development is increasingly appreciated. In this report, we present our study showing that microRNA-101 (miR-101 inhibits Ezh2 expression and differentially regulates prostate cancer cells. In addition, the expression of miR-101 alters upon androgen treatment and HIF-1α/HIF-1β induction. Result In our reporter assays, both miR-101 and miR-26a inhibit the expression of a reporter construct containing the 3'-UTR of Ezh2. When ectopically expressed in PC-3, DU145 and LNCaP cells, miR-101 inhibits endogenous Ezh2 expression in all three cell lines, while miR-26a only decreases Ezh2 in DU145. Ectopic miR-101 reduces the invasion ability of PC-3 cells, while restored Ezh2 expression rescues the invasiveness of PC-3 cells. Similarly, miR-101 also inhibits cell invasion and migration of DU145 and LNCaP cells, respectively. Interestingly, ectopic miR-101 exhibits differential effects on the proliferation of PC-3, DU-145 and LNCaP cells and also causes morphological changes of LNCaP cells. In addition, the expression of miR-101 is regulated by androgen receptor and HIF-1α/HIF-1β. While HIF-1α/HIF-1β induced by

Cannabinoids Regulate Bcl-2 and Cyclin D2 Expression in Pancreatic β Cells.

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Jihye Kim

Full Text Available Recent reports have shown that cannabinoid 1 receptors (CB1Rs are expressed in pancreatic β cells, where they induce cell death and cell cycle arrest by directly inhibiting insulin receptor activation. Here, we report that CB1Rs regulate the expression of the anti-apoptotic protein Bcl-2 and cell cycle regulator cyclin D2 in pancreatic β cells. Treatment of MIN6 and βTC6 cells with a synthetic CB1R agonist, WIN55,212-2, led to a decrease in the expression of Bcl-2 and cyclin D2, in turn inducing cell cycle arrest in G0/G1 phase and caspase-3-dependent apoptosis. Additionally, genetic deletion and pharmacological blockade of CB1Rs after injury in mice led to increased levels of Bcl-2 and cyclin D2 in pancreatic β cells. These findings provide evidence for the involvement of Bcl-2 and cyclin D2 mediated by CB1Rs in the regulation of β-cell survival and growth, and will serve as a basis for developing new therapeutic interventions to enhance β-cell function and growth in diabetes.

Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses

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Fukuyama, Yoshiko; Tokuhara, Daisuke [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Division of Mucosal Immunology, Institute of Medical Science, University of Tokyo, Tokyo 108-8639 (Japan); Sekine, Shinichi [Department of Preventive Dentistry, Graduate School of Dentistry, Osaka University, Osaka 565-0871 (Japan); Kataoka, Kosuke [Department of Preventive Dentistry, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8504 (Japan); Markham, Jonathan D.; Irwin, Allyson R.; Moon, Grace H.; Tokuhara, Yuka; Fujihashi, Keiko [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Davydova, Julia; Yamamoto, Masato [Department of Surgery, University of Minnesota, Minneapolis, MN 55455 (United States); Gilbert, Rebekah S. [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States); Fujihashi, Kohtaro, E-mail: kohtarof@uab.edu [Department of Pediatric Dentistry, The Immunobiology Vaccine Center, The Institute of Oral Health Research, The University of Alabama at Birmingham, Birmingham, AL 35294-0007 (United States)

2012-02-03

Highlights: Black-Right-Pointing-Pointer Nasal Ad-FL effectively up-regulates APC function by CD11c{sup +} DCs in mucosal tissues. Black-Right-Pointing-Pointer Nasal Ad-FL induces Notch ligand (L)-expressing CD11c{sup +} DCs. Black-Right-Pointing-Pointer Notch L-expressing DCs support the induction of Th1- and Th2-type cytokine responses. -- Abstract: Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c{sup +} dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c{sup +} DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c{sup +} DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c{sup +} DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4{sup +} T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-{gamma}, IL-2 and IL-4 producing CD4{sup +} T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch-Notch-L pathway. These results show that Ad-FL induces CD11c{sup +} DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

Dosage-dependent copy number gains in E2f1 and E2f3 drive hepatocellular carcinoma.

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Kent, Lindsey N; Bae, Sooin; Tsai, Shih-Yin; Tang, Xing; Srivastava, Arunima; Koivisto, Christopher; Martin, Chelsea K; Ridolfi, Elisa; Miller, Grace C; Zorko, Sarah M; Plevris, Emilia; Hadjiyannis, Yannis; Perez, Miguel; Nolan, Eric; Kladney, Raleigh; Westendorp, Bart; de Bruin, Alain; Fernandez, Soledad; Rosol, Thomas J; Pohar, Kamal S; Pipas, James M; Leone, Gustavo

2017-03-01

Disruption of the retinoblastoma (RB) tumor suppressor pathway, either through genetic mutation of upstream regulatory components or mutation of RB1 itself, is believed to be a required event in cancer. However, genetic alterations in the RB-regulated E2F family of transcription factors are infrequent, casting doubt on a direct role for E2Fs in driving cancer. In this work, a mutation analysis of human cancer revealed subtle but impactful copy number gains in E2F1 and E2F3 in hepatocellular carcinoma (HCC). Using a series of loss- and gain-of-function alleles to dial E2F transcriptional output, we have shown that copy number gains in E2f1 or E2f3b resulted in dosage-dependent spontaneous HCC in mice without the involvement of additional organs. Conversely, germ-line loss of E2f1 or E2f3b, but not E2f3a, protected mice against HCC. Combinatorial mapping of chromatin occupancy and transcriptome profiling identified an E2F1- and E2F3B-driven transcriptional program that was associated with development and progression of HCC. These findings demonstrate a direct and cell-autonomous role for E2F activators in human cancer.

TNF-a-induced down-regulation of CDX2 suppresses MEP1A expression in colitis

DEFF Research Database (Denmark)

Coskun, Mehmet; Olsen, Anders Krüger; Holm, Thomas Lindebo

2012-01-01

was investigated in colonic biopsies of ulcerative colitis (UC) patients and in dextran sodium sulfate (DSS)-induced colitis. CDX2 protein expression was investigated by immunoblotting and immunohistochemical procedures. CDX2 and MEP1A regulation was examined in TNF-a-treated Caco-2 cells by reverse transcription...

Regulating the ethylene response of a plant by modulation of F-box proteins

Science.gov (United States)

Guo, Hongwei [Beijing, CN; Ecker, Joseph R [Carlsbad, CA

2014-01-07

The relationship between F-box proteins and proteins invovled in the ethylene response in plants is described. In particular, F-box proteins may bind to proteins involved in the ethylene response and target them for degradation by the ubiquitin/proteasome pathway. The transcription factor EIN3 is a key transcription factor mediating ethylne-regulated gene expression and morphological responses. EIN3 is degraded through a ubiquitin/proteasome pathway mediated by F-box proteins EBF1 and EBF2. The link between F-box proteins and the ethylene response is a key step in modulating or regulating the response of a plant to ethylene. Described herein are transgenic plants having an altered sensitivity to ethylene, and methods for making transgenic plant haing an althered sensitivity to ethylene by modulating the level of activity of F-box proteins. Methods of altering the ethylene response in a plant by modulating the activity or expression of an F-box protein are described. Also described are methods of identifying compounds that modulate the ethylene response in plants by modulating the level of F-box protein expression or activity.

Regulation of hemeoxygenase-1 gene expression by Nrf2 and c-Jun in tertiary butylhydroquinone-stimulated rat primary astrocytes

International Nuclear Information System (INIS)

Park, Jin-Sun; Kim, Hee-Sun

2014-01-01

Highlights: • tBHQ increased HO-1 mRNA and protein levels in rat primary astrocytes. • tBHQ enhanced HO-1 gene transcription in an ARE-dependent manner. • tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. • Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. • Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction. - Abstract: Hemeoxygenase-1 (HO-1) is a phase II antioxidant enzyme that is primarily involved in detoxification and cytoprotection in a variety of tissues. However, the mechanism underlying HO-1 gene expression remains unclear. In the present study, we investigated the regulation of HO-1 expression in primary cultured astrocytes by using the natural antioxidant compound tertiary butylhydroquinone (tBHQ). We found that tBHQ increased HO-1 mRNA and protein levels. Promoter analysis revealed that tBHQ enhanced HO-1 gene transcription in an antioxidant response element (ARE)-dependent manner. In addition, tBHQ increased the nuclear translocation and DNA binding of Nrf2 and c-Jun to ARE. Small interfering RNA (siRNA) experiments demonstrated that Nrf2 and c-Jun are involved in the differential modulation of HO-1 expression. Thus, Nrf2 knockdown reduced the basal level of HO-1 expression but did not affect the fold induction by tBHQ. On the other hand, knockdown of c-Jun diminished tBHQ-mediated induction of HO-1 without affecting basal expression. The data suggest that Nrf2 generally modulates the basal expression of HO-1, while c-Jun mediates HO-1 induction in response to tBHQ. The results of co-immunoprecipitation assays demonstrated a physical interaction between Nrf2 and c-Jun in tBHQ-treated astrocytes. The results suggest that Nrf2 and c-Jun regulate HO-1 expression via their coordinated interaction in tBHQ-treated rat primary astrocytes

Integration of TP53, DREAM, MMB-FOXM1 and RB-E2F target gene analyses identifies cell cycle gene regulatory networks.

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Fischer, Martin; Grossmann, Patrick; Padi, Megha; DeCaprio, James A

2016-07-27

Cell cycle (CC) and TP53 regulatory networks are frequently deregulated in cancer. While numerous genome-wide studies of TP53 and CC-regulated genes have been performed, significant variation between studies has made it difficult to assess regulation of any given gene of interest. To overcome the limitation of individual studies, we developed a meta-analysis approach to identify high confidence target genes that reflect their frequency of identification in independent datasets. Gene regulatory networks were generated by comparing differential expression of TP53 and CC-regulated genes with chromatin immunoprecipitation studies for TP53, RB1, E2F, DREAM, B-MYB, FOXM1 and MuvB. RNA-seq data from p21-null cells revealed that gene downregulation by TP53 generally requires p21 (CDKN1A). Genes downregulated by TP53 were also identified as CC genes bound by the DREAM complex. The transcription factors RB, E2F1 and E2F7 bind to a subset of DREAM target genes that function in G1/S of the CC while B-MYB, FOXM1 and MuvB control G2/M gene expression. Our approach yields high confidence ranked target gene maps for TP53, DREAM, MMB-FOXM1 and RB-E2F and enables prediction and distinction of CC regulation. A web-based atlas at www.targetgenereg.org enables assessing the regulation of any human gene of interest. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Dock/Nck facilitates PTP61F/PTP1B regulation of insulin signalling.

Science.gov (United States)

Wu, Chia-Lun; Buszard, Bree; Teng, Chun-Hung; Chen, Wei-Lin; Warr, Coral G; Tiganis, Tony; Meng, Tzu-Ching

2011-10-01

PTP1B (protein tyrosine phosphatase 1B) is a negative regulator of IR (insulin receptor) activation and glucose homoeostasis, but the precise molecular mechanisms governing PTP1B substrate selectivity and the regulation of insulin signalling remain unclear. In the present study we have taken advantage of Drosophila as a model organism to establish the role of the SH3 (Src homology 3)/SH2 adaptor protein Dock (Dreadlocks) and its mammalian counterpart Nck in IR regulation by PTPs. We demonstrate that the PTP1B orthologue PTP61F dephosphorylates the Drosophila IR in S2 cells in vitro and attenuates IR-induced eye overgrowth in vivo. Our studies indicate that Dock forms a stable complex with PTP61F and that Dock/PTP61F associate with the IR in response to insulin. We report that Dock is required for effective IR dephosphorylation and inactivation by PTP61F in vitro and in vivo. Furthermore, we demonstrate that Nck interacts with PTP1B and that the Nck/PTP1B complex inducibly associates with the IR for the attenuation of IR activation in mammalian cells. Our studies reveal for the first time that the adaptor protein Dock/Nck attenuates insulin signalling by recruiting PTP61F/PTP1B to its substrate, the IR.

Bioatividade de produtos fitossanitários utilizados na cultura do tomateiro (Lycopersicon esculentum Mill. a Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae nas gerações F1 e F2 Bioactivity of pesticides used in tomato (Lycopersicon esculentum Mill. crop to Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae in F1 and F2 generations

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Geraldo Andrade Carvalho

2003-04-01

Full Text Available A bioatividade de dezoito produtos químicos utilizados no controle de pragas e doenças do tomateiro, sobre duas linhagens de Trichogramma pretiosum Riley, 1879 (L9=Alegre, ES e L10= Venda Nova do Imigrante, ES, nas gerações F1 e F2, foi investigada em laboratório. Ovos de Anagasta kuehniella (Zeller contendo o parasitóide em diferentes estágios de desenvolvimento (ovo-larva, pré-pupa e pupa foram tratados por meio de imersão nas respectivas caldas químicas. Os inseticidas triflumuron, clorfluazuron, deltametrina, Bacillus thuringiensis, lambdacialotrina, teflubenzuron, acefato, pirimicarb e ciromazina, e os fungicidas benomil, iprodiona, clorotalonil e dimetomorf, independente da linhagem, não reduziram a longevidade das fêmeas de T. pretiosum da geração F1. Os inseticidas abamectin, cartap, metamidofós e lambdacialotrina afetaram a razão sexual de indivíduos da geração F1, e não reduziram a taxa de emergência de parasitóides da F2, independente do estágio de desenvolvimento e da origem da população de T. pretiosum. Parasitóides de Venda Nova do Imigrante, ES (L10 mostraram-se mais susceptíveis que os de Alegre, ES (L9 aos efeitos dos compostos avaliados. De modo geral, a fase de pupa de T. pretiosum, independente da população, apresentou maior tolerância aos produtos testados. Recomenda-se a realização de novos testes para outras populações desse parasitóide que serão utilizadas no controle de pragas, pois podem responder de forma diversa aos produtos fitossanitários avaliados.The bioactivity of eighteen pesticides commonly used to pests and diseases control on tomato, in two strains of Trichogramma pretiosum Riley, 1879 (L9=Alegre, ES and L10= Venda Nova do Imigrante, ES, Brazil in F1 and F2 generations, was evaluated under laboratory conditions. The bioassays were conducted in a climatic chamber at 25 ± 2 ºC, 60 ± 10% RH and 14 hours of photophase. Eggs of Anagasta kuehniella (Zeller containing the

The FTF gene family regulates virulence and expression of SIX effectors in Fusarium oxysporum.

Science.gov (United States)

Niño-Sánchez, Jonathan; Casado-Del Castillo, Virginia; Tello, Vega; De Vega-Bartol, José J; Ramos, Brisa; Sukno, Serenella A; Díaz Mínguez, José María

2016-09-01

The FTF (Fusarium transcription factor) gene family comprises a single copy gene, FTF2, which is present in all the filamentous ascomycetes analysed, and several copies of a close relative, FTF1, which is exclusive to Fusarium oxysporum. An RNA-mediated gene silencing system was developed to target mRNA produced by all the FTF genes, and tested in two formae speciales: F. oxysporum f. sp. phaseoli (whose host is common bean) and F. oxysporum f. sp. lycopersici (whose host is tomato). Quantification of the mRNA levels showed knockdown of FTF1 and FTF2 in randomly isolated transformants of both formae speciales. The attenuation of FTF expression resulted in a marked reduction in virulence, a reduced expression of several SIX (Secreted In Xylem) genes, the best studied family of effectors in F. oxysporum, and lower levels of SGE1 (Six Gene Expression 1) mRNA, the presumptive regulator of SIX expression. Moreover, the knockdown mutants showed a pattern of colonization of the host plant similar to that displayed by strains devoid of FTF1 copies (weakly virulent strains). Gene knockout of FTF2 also resulted in a reduction in virulence, but to a lesser extent. These results demonstrate the role of the FTF gene expansion, mostly the FTF1 paralogues, as a regulator of virulence in F. oxysporum and suggest that the control of effector expression is the mechanism involved. © 2016 The Authors Molecular Plant Pathology Published by British Society for Plant Pathology and John Wiley & Sons Ltd.

Bim and Mcl-1 exert key roles in regulating JAK2V617F cell survival

International Nuclear Information System (INIS)

Rubert, Joëlle; Qian, Zhiyan; Andraos, Rita; Guthy, Daniel A; Radimerski, Thomas

2011-01-01

The JAK2 V617F mutation plays a major role in the pathogenesis of myeloproliferative neoplasms and is found in the vast majority of patients suffering from polycythemia vera and in roughly every second patient suffering from essential thrombocythemia or from primary myelofibrosis. The V617F mutation is thought to provide hematopoietic stem cells and myeloid progenitors with a survival and proliferation advantage. It has previously been shown that activated JAK2 promotes cell survival by upregulating the anti-apoptotic STAT5 target gene Bcl-xL. In this study, we have investigated the role of additional apoptotic players, the pro-apoptotic protein Bim as well as the anti-apoptotic protein Mcl-1. Pharmacological inhibition of JAK2/STAT5 signaling in JAK2 V617F mutant SET-2 and MB-02 cells was used to study effects on signaling, cell proliferation and apoptosis by Western blot analysis, WST-1 proliferation assays and flow cytometry. Cells were transfected with siRNA oligos to deplete candidate pro- and anti-apoptotic proteins. Co-immunoprecipitation assays were performed to assess the impact of JAK2 inhibition on complexes of pro- and anti-apoptotic proteins. Treatment of JAK2 V617F mutant cell lines with a JAK2 inhibitor was found to trigger Bim activation. Furthermore, Bim depletion by RNAi suppressed JAK2 inhibitor-induced cell death. Bim activation following JAK2 inhibition led to enhanced sequestration of Mcl-1, besides Bcl-xL. Importantly, Mcl-1 depletion by RNAi was sufficient to compromise JAK2 V617F mutant cell viability and sensitized the cells to JAK2 inhibition. We conclude that Bim and Mcl-1 have key opposing roles in regulating JAK2 V617F cell survival and propose that inactivation of aberrant JAK2 signaling leads to changes in Bim complexes that trigger cell death. Thus, further preclinical evaluation of combinations of JAK2 inhibitors with Bcl-2 family antagonists that also tackle Mcl-1, besides Bcl-xL, is warranted to assess the therapeutic potential

Evaluación energética de los generadores de vapor F1-2 y BH-109 de una refinería Cubana de petróleo.

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Anliet Valles Cruz

2014-03-01

Full Text Available La refinería cubana produce muchos productos para el mercado cubano como los combustibles, aceites, asfaltos y Jet-A1. Los sistemas auxiliares como vapor, aire comprimido y agua se utilizan para la obtención de los productos derivados del petróleo. La generación de vapor es uno de los sistemas auxiliares más importantes dentro de la refinería. La caldera de vapor garantiza que el vapor tenga las condiciones de operación de acuerdo con las normas internacionales. En este trabajo, se realizó la evaluación energética de F1-2 y BH-109 de calderas que utilizan los balances de energía y de masas convencionales. Se obtuvo una eficiencia energética de 61,89 y 77,31 por ciento para F1-2 y BH-109, respectivamente. Las principales pérdidas se debieron al calor sensible de los gases de combustión y a la combustión no química. Para reducir estas pérdidas, mejorar el rendimiento de la caldera y disminuir la temperatura de los gases de salida, se recomienda montar el sistema de control de exceso de aire y volver a examinar o cambiar el sistema de inyección de aire.

Krüppel-like factor 1 mutations and expression of hemoglobins F and A2 in homozygous hemoglobin E syndrome.

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Tepakhan, Wanicha; Yamsri, Supawadee; Fucharoen, Goonnapa; Sanchaisuriya, Kanokwan; Fucharoen, Supan

2015-07-01

The basis for variability of hemoglobin (Hb) F in homozygous Hb E disease is not well understood. We have examined multiple mutations of the Krüppel-like factor 1 (KLF1) gene; an erythroid specific transcription factor and determined their associations with Hbs F and A2 expression in homozygous Hb E. Four KLF1 mutations including G176AfsX179, T334R, R238H, and -154 (C-T) were screened using specific PCR assays on 461 subjects with homozygous Hb E and 100 normal controls. None of these four mutations were observed in 100 normal controls. Among 461 subjects with homozygous Hb E, 306 had high (≥5 %) and 155 had low (<5 %) Hb F. DNA analysis identified the KLF1 mutations in 35 cases of the former group with high Hb F, including the G176AfsX179 mutation (17/306 = 5.6 %), T334R mutation (9/306 = 2.9 %), -154 (C-T) mutation (7/306 = 2.3 %), and R328H mutation (2/306 = 0.7 %). Only two subjects in the latter group with low Hb F carried the G176AfsX179 and -154 (C-T) mutations. Significant higher Hb A2 level was observed in those of homozygous Hb E with the G176AfsX179 mutation as compared to those without KLF1 mutations. These results indicate that KLF1 is among the genetic factors associated with increased Hbs F and A2, and in combination with other factors could explain the variabilities of these Hb expression in Hb E syndrome.

Gln3p and Nil1p regulation of invertase activity and SUC2 expression in Saccharomyces cerevisiae.

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Oliveira, Edna Maria Morais; Mansure, José João; Bon, Elba Pinto da Silva

2005-04-01

In Saccharomyces cerevisiae, sensing and signalling pathways regulate gene expression in response to quality of carbon and nitrogen sources. One such system, the target of rapamycin (Tor) proteins, senses nutrients and uses the GATA activators Gln3p and Nil1p to regulate translation in response to low-quality carbon and nitrogen. The signal transduction, triggered in response to nitrogen nutrition that is sensed by the Tor proteins, operates via a regulatory pathway involving the cytoplasmic factor Ure2p. When carbon and nitrogen are abundant, the phosphorylated Ure2p anchors the also phosphorylated Gln3p and Nil1p in the cytoplasm. Upon a shift from high- to low-quality nitrogen or treatment with rapamycin all three proteins are dephosphorylated, causing Gln3p and Nil1p to enter the nucleus and promote transcription. The genes that code for yeast periplasmic enzymes with nutritional roles would be obvious targets for regulation by the sensing and signalling pathways that respond to quality of carbon and nitrogen sources. Indeed, previous results from our laboratory had shown that the GATA factors Gln3p, Nil1p, Dal80p, Nil2p and also the protein Ure2 regulate the expression of asparaginase II, coded by ASP3. We also had observed that the activity levels of the also periplasmic invertase, coded by SUC2, were 6-fold lower in ure2 mutant cells in comparison to wild-type cells collected at stationary phase. These results suggested similarities between the signalling pathways regulating the expression of ASP3 and SUC2. In the present work we showed that invertase levels displayed by the single nil1 and gln3 and by the double gln3nil1 mutant cells, cultivated in a sucrose-ammonium medium and collected at the exponential phase, were 6-, 10- and 60-fold higher, respectively, in comparison to their wild-type counterparts. RT-PCR data of SUC2 expression in the double-mutant cells indicated a 10-fold increase in the mRNA(SUC2) levels.

Human Freud-2/CC2D1B: a novel repressor of postsynaptic serotonin-1A receptor expression.

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Hadjighassem, Mahmoud R; Austin, Mark C; Szewczyk, Bernadeta; Daigle, Mireille; Stockmeier, Craig A; Albert, Paul R

2009-08-01

Altered expression of serotonin-1A (5-HT1A) receptors, both presynaptic in the raphe nuclei and post-synaptic in limbic and cortical target areas, has been implicated in mood disorders such as major depression and anxiety. Within the 5-HT1A receptor gene, a powerful dual repressor element (DRE) is regulated by two protein complexes: Freud-1/CC2D1A and a second, unknown repressor. Here we identify human Freud-2/CC2D1B, a Freud-1 homologue, as the second repressor. Freud-2 distribution was examined with Northern and Western blot, reverse transcriptase polymerase chain reaction, and immunohistochemistry/immunofluorescence; Freud-2 function was examined by electrophoretic mobility shift, reporter assay, and Western blot. Freud-2 RNA was widely distributed in brain and peripheral tissues. Freud-2 protein was enriched in the nuclear fraction of human prefrontal cortex and hippocampus but was weakly expressed in the dorsal raphe nucleus. Freud-2 immunostaining was co-localized with 5-HT1A receptors, neuronal and glial markers. In prefrontal cortex, Freud-2 was expressed at similar levels in control and depressed male subjects. Recombinant hFreud-2 protein bound specifically to 5' or 3' human DRE adjacent to the Freud-1 site. Human Freud-2 showed strong repressor activity at the human 5-HT1A or heterologous promoter in human HEK-293 5-HT1A-negative cells and neuronal SK-N-SH cells, a model of postsynaptic 5-HT1A receptor-positive cells. Furthermore, small interfering RNA knockdown of endogenous hFreud-2 expression de-repressed 5-HT1A promoter activity and increased levels of 5-HT1A receptor protein in SK-N-SH cells. Human Freud-2 binds to the 5-HT1A DRE and represses the human 5-HT1A receptor gene to regulate its expression in non-serotonergic cells and neurons.

Prostaglandin F2α–F-Prostanoid Receptor Signalling Promotes Neutrophil Chemotaxis via Chemokine (CXC motif) Ligand-1 in Endometrial Adenocarcinoma

Science.gov (United States)

Wallace, Alison E; Sales, Kurt J; Catalano, Roberto D; Anderson, Richard A; Williams, Alistair RW; Wilson, Martin R; Schwarze, Jurgen; Wang, Hongwei; Rossi, Adriano G; Jabbour, Henry N

2009-01-01

The prostaglandin F2α (PGF2α) receptor (FP) is elevated in endometrial adenocarcinoma. This study found that PGF2α signalling via FP regulates expression of chemokine (C-X-C motif) ligand 1 (CXCL1) in endometrial adenocarcinoma cells. Expression of CXCL1 and its receptor, CXCR2, are elevated in cancer tissue as compared to normal endometrium and localised to glandular epithelium, endothelium and stroma. Treatment of Ishikawa cells stably transfected with the FP receptor (FPS cells) with 100nM PGF2α increased CXCL1 promoter activity, mRNA and protein expression, and these effects were abolished by co-treatment of cells with FP antagonist or chemical inhibitors of Gq, EGFR and ERK. Similarly, CXCL1 was elevated in response to 100 nM PGF2α in endometrial adenocarcinoma explant tissue. CXCL1 is a potent neutrophil chemoattractant. The expression of CXCR2 colocalised to neutrophils in endometrial adenocarcinoma and increased neutrophils were present in endometrial adenocarcinoma compared with normal endometrium. Conditioned media from PGF2α-treated FPS cells stimulated neutrophil chemotaxis which could be abolished by CXCL1 protein immunoneutralisation of the conditioned media or antagonism of CXCR2. Finally, xenograft tumours in nude mice arising from inoculation with FPS cells showed increased neutrophil infiltration compared to tumours arising from wild-type cells or following treatment of mice bearing FPS tumours with CXCL1-neutralising antibody. In conclusion, our results demonstrate a novel PGF2α-FP pathway that may regulate the inflammatory microenvironment in endometrial adenocarcinoma via neutrophil chemotaxis. PMID:19549892

Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression

Energy Technology Data Exchange (ETDEWEB)

Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J

1998-06-29

Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.

Transient expression of the influenza A virus PB1-F2 protein using a plum pox virus-based vector in Nicotiana benthamiana.

Science.gov (United States)

Kamencayová, M; Košík, I; Hunková, J; Subr, Z W

2014-01-01

PB1-F2 protein of influenza A virus (IAV) was cloned in a plum pox virus (PPV) genome-based vector and attempts to express it in biolistically transfected Nicotiana benthamiana plants were performed. The vector-insert construct replicated in infected plants properly and was stable during repeated passage by mechanical inoculation, as demonstrated by disease symptoms and immunoblot detection of PPV capsid protein, while PB1-F2-specific band was more faint. We showed that it was due its low solubility. Modification of sample preparation (denaturation/solubilization preceding the centrifugation of cell debris) led to substantial signal enhancement. Maximal level of PB1-F2 expression in plants was observed 12 days post inoculation (dpi). Only 1% SDS properly solubilized the protein, other detergents were much less efficient. Solubilization with 8M urea released approximately 50% of PB1-F2 from the plant tissues, thus the treatment with this removable chaotropic agent may be a good starting point for the purification of the protein for eventual functional studies in the future.

Glycogen synthase kinase 3 regulates expression of nuclear factor-erythroid-2 related transcription factor-1 (Nrf1) and inhibits pro-survival function of Nrf1

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

2013-08-01

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

Androgen-Dependent Regulation of Human MUC1 Mucin Expression

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Stephen Mitchell

2002-01-01

Full Text Available MUC1 mucin is transcriptionally regulated by estrogen, progesterone, and glucocorticoids. Our objective was to determine whether androgen receptor. (20AR activation regulates expression of MUC1. The following breast and prostatic cell lines were phenotyped and grouped according to AR and MUC1protein expression: 1 AR+MUCi + [DAR17+19. (20AR transfectants of DU-145, ZR-75-1, MDA-MB-453, and T47D]; 2 AR-MUCi+ [DZeoi. (20AR- vector control, DU-145, BT20, MDA-MB231, and MCF7]; 3 AIR +MUCi -. (20LNCaP and LNCaP-r. Cell proliferation was determined using the MTT assay in the presence of synthetic androgen R1881, 0.1 pM to 1 µM. Cell surface MUC1expression was determined by flow cytometry in the presence or absence of oestradiol, medroxy progesterone acetate or R1881, with and without 4 hydroxy-flutamide. (204-OH, a nonsteroidal AR antagonist. The functional significance of MUC1expression was investigated with a cell-cell aggregation assay. Only AR+ MUC1 + cell lines showed a significant increase in MUC1expression with AR activation. (20P. (20range =.01 to .0001, reversed in the presence of 4-OHF. Cell proliferation was unaffected. Increased expression of MUC1was associated with a significant. (20P. (20range =.002 to .001 reduction in cell-cell adhesion. To our knowledge, this is the first description of androgen-dependent regulation of MUC1mucin. This is also functionally associated with decreased cell-cell adhesion, a recognised feature of progressive malignancy. These findings have important implications for physiological and pathological processes.

Depressão endogâmica e heterose de híbridos de populações F2 de milho no estado de São Paulo

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Cristiani Santos Bernini

2013-01-01

Full Text Available A heterose e a depressão por endogamia são fenômenos complementares importantes nas estratégias de melhoramento, como para a obtenção de híbridos convencionais e melhoramento de populações. Este trabalho teve por objetivos avaliar híbridos de populações F2 de milho quanto aos caracteres agronômicos, estimar a heterose em relação à média dos pais e determinar a depressão endogâmica na obtenção das populações de genitores F2. Foram avaliados 10 híbridos de populações F2, cinco populações de genitores F2 e os respectivos híbridos comerciais (HC quanto aos seguintes caracteres agronômicos: florescimento masculino (FM, altura de planta (AP, altura de espiga (AE e massa de grãos (MG, em dois locais do estado de São Paulo, Mococa e Palmital, sob delineamento de blocos ao acaso. A estimativa de depressão por endogamia ao passar da geração F1 para F2 variou de 18,0% no HC12 a 48,1% no HC10, para MG. A heterose média em relação à média dos pais obtida para massa de grãos foi de 37,2%, representada pela elevada produtividade alcançada pelos híbridos de F2. Baseando-se nesses resultados foi possível evidenciar dois híbridos de populações F2 que apresentaram potencial produtivo, alta heterose média e populações F2 com potencial para extração de linhagens.

The Response Regulator YycF Inhibits Expression of the Fatty Acid Biosynthesis Repressor FabT in Streptococcus pneumoniae

Science.gov (United States)

Mohedano, Maria L.; Amblar, Mónica; de la Fuente, Alicia; Wells, Jerry M.; López, Paloma

2016-01-01

The YycFG (also known as WalRK, VicRK, MicAB, or TCS02) two-component system (TCS) is highly conserved among Gram-positive bacteria with a low G+C content. In Streptococcus pneumoniae the YycF response regulator has been reported to be essential due to its control of pcsB gene expression. Previously we showed that overexpression of yycF in S. pneumoniae TIGR4 altered the transcription of genes involved in cell wall metabolism and fatty acid biosynthesis, giving rise to anomalous cell division and increased chain length of membrane fatty acids. Here, we have overexpressed the yycFG system in TIGR4 wild-type strain and yycF in a TIGR4 mutant depleted of YycG, and analyzed their effects on expression of proteins involved in fatty acid biosynthesis during activation of the TCS. We demonstrate that transcription of the fab genes and levels of their products were only altered in the YycF overexpressing strain, indicating that the unphosphorylated form of YycF is involved in the regulation of fatty acid biosynthesis. In addition, DNA-binding assays and in vitro transcription experiments with purified YycF and the promoter region of the FabTH-acp operon support a direct inhibition of transcription of the FabT repressor by YycF, thus confirming the role of the unphosphorylated form in transcriptional regulation. PMID:27610104

Cloning and characterization of two duplicated interleukin-17A/F2 genes in common carp (Cyprinus carpio L.): Transcripts expression and bioactivity of recombinant IL-17A/F2.

Science.gov (United States)

Li, Hongxia; Yu, Juhua; Li, Jianlin; Tang, Yongkai; Yu, Fan; Zhou, Jie; Yu, Wenjuan

2016-04-01

Interleukin-17 (IL-17) plays an important role in inflammation and host defense in mammals. In this study, we identified two duplicated IL-17A/F2 genes in the common carp (Cyprinus carpio) (ccIL-17A/F2a and ccIL-17A/F2b), putative encoded proteins contain 140 amino acids (aa) with conserved IL-17 family motifs. Expression analysis revealed high constitutive expression of ccIL-17A/F2s in mucosal tissues, including gill, skin and intestine, their expression could be induced by Aeromonas hydrophila, suggesting a potential role in mucosal immunity. Recombinant ccIL-17A/F2a protein (rccIL-17A/F2a) produced in Escherichia coli could induce the expression of proinflammatory cytokines (IL-1β) and the antimicrobial peptides S100A1, S100A10a and S100A10b in the primary kidney in a dose- and time-dependent manner. Above findings suggest that ccIL-17A/F2 plays an important role in both proinflammatory and innate immunity. Two duplicated ccIL-17A/F2s showed different expression level with ccIL-17A/F2a higher than b, comparison of two 5' regulatory regions indicated the length from anticipated promoter to transcriptional start site (TSS) and putative transcription factor binding site (TFBS) were different. Promoter activity of ccIL-17A/F2a was 2.5 times of ccIL-17A/F2b which consistent with expression results of two genes. These suggest mutations in 5'regulatory region contributed to the differentiation of duplicated genes. To our knowledge, this is the first report to analyze 5'regulatory region of piscine IL-17 family genes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

International Nuclear Information System (INIS)

Hamidian, Arash; Stedingk, Kristoffer von; Munksgaard Thorén, Matilda; Mohlin, Sofie; Påhlman, Sven

2015-01-01

Hypoxia-inducible factors (HIFs) are differentially regulated in tumor cells. While the current paradigm supports post-translational regulation of the HIF-α subunits, we recently showed that hypoxic HIF-2α is also transcriptionally regulated via insulin-like growth factor (IGF)-II in the childhood tumor neuroblastoma. Here, we demonstrate that transcriptional regulation of HIF-2α seems to be restricted to neural cell-derived tumors, while HIF-1α is canonically regulated at the post-translational level uniformly across different tumor forms. Enhanced expression of HIF2A mRNA at hypoxia is due to de novo transcription rather than increased mRNA stability, and chemical stabilization of the HIF-α proteins at oxygen-rich conditions unexpectedly leads to increased HIF2A transcription. The enhanced HIF2A levels do not seem to be dependent on active HIF-1. Using a transcriptome array approach, we identified members of the Peroxisome proliferator-activated receptor gamma coactivator (PGC)/Estrogen-related receptor (ERR) complex families as potential regulators of HIF2A. Knockdown or inhibition of one of the members, ERRα, leads to decreased expression of HIF2A, and high expression of the ERRα gene ESRRA correlates with poor overall and progression-free survival in a clinical neuroblastoma material consisting of 88 tumors. Thus, targeting of ERRα and pathways regulating transcriptional HIF-2α are promising therapeutic avenues in neuroblastoma. - Highlights: • Transcriptional control of HIF-2α is restricted to neural cell-derived tumors. • Enhanced transcription of HIF2A is not due to increased mRNA stability. • Chemical stabilization of the HIF-α subunits leads to increased HIF2A transcription. • ERRα regulates HIF2A mRNA expression in neuroblastoma. • High expression of ESRRA correlates to poor outcome in neuroblastoma

Differential regulation of HIF-1α and HIF-2α in neuroblastoma: Estrogen-related receptor alpha (ERRα) regulates HIF2A transcription and correlates to poor outcome

Energy Technology Data Exchange (ETDEWEB)

Hamidian, Arash; Stedingk, Kristoffer von; Munksgaard Thorén, Matilda; Mohlin, Sofie; Påhlman, Sven, E-mail: sven.pahlman@med.lu.se

2015-06-05

Hypoxia-inducible factors (HIFs) are differentially regulated in tumor cells. While the current paradigm supports post-translational regulation of the HIF-α subunits, we recently showed that hypoxic HIF-2α is also transcriptionally regulated via insulin-like growth factor (IGF)-II in the childhood tumor neuroblastoma. Here, we demonstrate that transcriptional regulation of HIF-2α seems to be restricted to neural cell-derived tumors, while HIF-1α is canonically regulated at the post-translational level uniformly across different tumor forms. Enhanced expression of HIF2A mRNA at hypoxia is due to de novo transcription rather than increased mRNA stability, and chemical stabilization of the HIF-α proteins at oxygen-rich conditions unexpectedly leads to increased HIF2A transcription. The enhanced HIF2A levels do not seem to be dependent on active HIF-1. Using a transcriptome array approach, we identified members of the Peroxisome proliferator-activated receptor gamma coactivator (PGC)/Estrogen-related receptor (ERR) complex families as potential regulators of HIF2A. Knockdown or inhibition of one of the members, ERRα, leads to decreased expression of HIF2A, and high expression of the ERRα gene ESRRA correlates with poor overall and progression-free survival in a clinical neuroblastoma material consisting of 88 tumors. Thus, targeting of ERRα and pathways regulating transcriptional HIF-2α are promising therapeutic avenues in neuroblastoma. - Highlights: • Transcriptional control of HIF-2α is restricted to neural cell-derived tumors. • Enhanced transcription of HIF2A is not due to increased mRNA stability. • Chemical stabilization of the HIF-α subunits leads to increased HIF2A transcription. • ERRα regulates HIF2A mRNA expression in neuroblastoma. • High expression of ESRRA correlates to poor outcome in neuroblastoma.

E2F-HDAC complexes negatively regulate the tumor suppressor gene ARHI in breast cancer

DEFF Research Database (Denmark)

Lu, Z; Luo, R Z; Peng, H

2006-01-01

. While the retinoblastoma protein, pRB, alone had no effect on ARHI promoter activity, repression by E2F1, but not E2F4, was enhanced by the coexpression of pRB. Taken together, our results suggest that E2F1, 4 and their complexes with HDAC play an important role in downregulating the expression...

Trichloroethylene-induced gene expression and DNA methylation changes in B6C3F1 mouse liver.

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Yan Jiang

Full Text Available Trichloroethylene (TCE, widely used as an organic solvent in the industry, is a common contaminant in air, soil, and water. Chronic TCE exposure induced hepatocellular carcinoma in mice, and occupational exposure in humans was suggested to be associated with liver cancer. To understand the role of non-genotoxic mechanism(s for TCE action, we examined the gene expression and DNA methylation changes in the liver of B6C3F1 mice orally administered with TCE (0, 100, 500 and 1000 mg/kg b.w. per day for 5 days. After 5 days TCE treatment at a dose level of 1000 mg/kg b.w., a total of 431 differentially expressed genes were identified in mouse liver by microarray, of which 291 were up-regulated and 140 down-regulated. The expression changed genes were involved in key signal pathways including PPAR, proliferation, apoptosis and homologous recombination. Notably, the expression level of a number of vital genes involved in the regulation of DNA methylation, such as Utrf1, Tet2, DNMT1, DNMT3a and DNMT3b, were dysregulated. Although global DNA methylation change was not detected in the liver of mice exposed to TCE, the promoter regions of Cdkn1a and Ihh were found to be hypo- and hypermethylated respectively, which correlated negatively with their mRNA expression changes. Furthermore, the gene expression and DNA methylation changes induced by TCE were dose dependent. The overall data indicate that TCE exposure leads to aberrant DNA methylation changes, which might alter the expression of genes involved in the TCE-induced liver tumorgenesis.

Transforming growth factor β-activated kinase 1 negatively regulates interleukin-1α-induced stromal-derived factor-1 expression in vascular smooth muscle cells

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Yang, Bin [Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huangzhong University of Science and Technology, Wuhan 430022 (China); Li, Wei [Department of Gerontology, Union Hospital, Tongji Medical College, Huangzhong University of Science and Technology, Wuhan 430022 (China); Zheng, Qichang [Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huangzhong University of Science and Technology, Wuhan 430022 (China); Qin, Tao [Department of Hepatobiliary Pancreatic Surgery, People' s Hospital of Zhengzhou University, School of Medicine, Zhengzhou University, Zhengzhou 450003 (China); Wang, Kun; Li, Jinjin; Guo, Bing; Yu, Qihong; Wu, Yuzhe; Gao, Yang; Cheng, Xiang; Hu, Shaobo; Kumar, Stanley Naveen [Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huangzhong University of Science and Technology, Wuhan 430022 (China); Liu, Sanguang, E-mail: sanguang1998@sina.com [Department of Hepatobiliary Surgery, The Second Hospital, Hebei Medical University, Shijiazhuang 050000 (China); Song, Zifang, E-mail: zsong@hust.edu.cn [Department of Hepatobiliary Surgery, Union Hospital, Tongji Medical College, Huangzhong University of Science and Technology, Wuhan 430022 (China)

2015-07-17

Stromal-derived Factor-1 (SDF-1) derived from vascular smooth muscle cells (VSMCs) contributes to vascular repair and remodeling in various vascular diseases. In this study, the mechanism underlying regulation of SDF-1 expression by interleukin-1α (IL-1α) was investigated in primary rat VSMCs. We found IL-1α promotes SDF-1 expression by up-regulating CCAAT-enhancer-binding protein β (C/EBPβ) in an IκB kinase β (IKKβ) signaling-dependent manner. Moreover, IL-1α-induced expression of C/EBPβ and SDF-1 was significantly potentiated by knockdown of transforming growth factor β-activated kinase 1 (TAK1), an upstream activator of IKKβ signaling. In addition, we also demonstrated that TAK1/p38 mitogen-activated protein kinase (p38 MAPK) signaling exerted negative effect on IL-1α-induced expression of C/EBPβ and SDF-1 through counteracting ROS-dependent up-regulation of nuclear factor erythroid 2-related factor 2 (NRF2). In conclusion, TAK1 acts as an important regulator of IL-1α-induced SDF-1 expression in VSMCs, and modulating activity of TAK1 may serve as a potential strategy for modulating vascular repair and remodeling. - Highlights: • IL-1α induces IKKβ signaling-dependent SDF-1 expression by up-regulating C/EBPβ. • Activation of TAK1 by IL-1α negatively regulates C/EBPβ-dependent SDF-1 expression. • IL-1α-induced TAK1/p38 MAPK signaling counteracts ROS-dependent SDF-1 expression. • TAK1 counteracts IL-1α-induced SDF-1 expression by attenuating NRF2 up-regulation.

Transforming growth factor β-activated kinase 1 negatively regulates interleukin-1α-induced stromal-derived factor-1 expression in vascular smooth muscle cells

International Nuclear Information System (INIS)

Yang, Bin; Li, Wei; Zheng, Qichang; Qin, Tao; Wang, Kun; Li, Jinjin; Guo, Bing; Yu, Qihong; Wu, Yuzhe; Gao, Yang; Cheng, Xiang; Hu, Shaobo; Kumar, Stanley Naveen; Liu, Sanguang; Song, Zifang

2015-01-01

Stromal-derived Factor-1 (SDF-1) derived from vascular smooth muscle cells (VSMCs) contributes to vascular repair and remodeling in various vascular diseases. In this study, the mechanism underlying regulation of SDF-1 expression by interleukin-1α (IL-1α) was investigated in primary rat VSMCs. We found IL-1α promotes SDF-1 expression by up-regulating CCAAT-enhancer-binding protein β (C/EBPβ) in an IκB kinase β (IKKβ) signaling-dependent manner. Moreover, IL-1α-induced expression of C/EBPβ and SDF-1 was significantly potentiated by knockdown of transforming growth factor β-activated kinase 1 (TAK1), an upstream activator of IKKβ signaling. In addition, we also demonstrated that TAK1/p38 mitogen-activated protein kinase (p38 MAPK) signaling exerted negative effect on IL-1α-induced expression of C/EBPβ and SDF-1 through counteracting ROS-dependent up-regulation of nuclear factor erythroid 2-related factor 2 (NRF2). In conclusion, TAK1 acts as an important regulator of IL-1α-induced SDF-1 expression in VSMCs, and modulating activity of TAK1 may serve as a potential strategy for modulating vascular repair and remodeling. - Highlights: • IL-1α induces IKKβ signaling-dependent SDF-1 expression by up-regulating C/EBPβ. • Activation of TAK1 by IL-1α negatively regulates C/EBPβ-dependent SDF-1 expression. • IL-1α-induced TAK1/p38 MAPK signaling counteracts ROS-dependent SDF-1 expression. • TAK1 counteracts IL-1α-induced SDF-1 expression by attenuating NRF2 up-regulation

DHA down-regulates phenobarbital-induced cytochrome P450 2B1 gene expression in rat primary hepatocytes by attenuating CAR translocation

International Nuclear Information System (INIS)

Li, C.-C.; Lii, C.-K.; Liu, K.-L.; Yang, J.-J.; Chen, H.-W.

2007-01-01

The constitutive androstane receptor (CAR) plays an important role in regulating the expression of detoxifying enzymes, including cytochrome P450 2B (CYP 2B). Phenobarbital (PB) induction of human CYP 2B6 and mouse CYP 2b10 has been shown to be mediated by CAR. Our previous study showed that PB-induced CYP 2B1 expression in rat primary hepatocytes is down-regulated by both n-6 and n-3 polyunsaturated fatty acids (PUFAs), especially docosahexaenoic acid (DHA); however, the mechanism for this down-regulation by DHA was previously unknown. The objective of the present study was to determine whether change in CAR translocation is involved in the down-regulation by n-6 and n-3 PUFAs of PB-induced CYP 2B1 expression in rat primary hepatocytes. We used 100 μM arachidonic acid, linoleic acid, eicosapentaenoic acid, and DHA to test this hypothesis. PB triggered the translocation of CAR from the cytosol into the nucleus in a dose-dependent and time-dependent manner in our hepatocyte system, and the CAR distribution in rat primary hepatocytes was significantly affected by DHA. DHA treatment decreased PB-inducible accumulation of CAR in the nuclear fraction and increased it in the cytosolic fraction in a dose-dependent manner. The down-regulation of CYP 2B1 expression by DHA occurred in a dose-dependent manner, and a similar pattern was found for the nuclear accumulation of CAR. The results of immunoprecipitation showed a CAR/RXR heterodimer bound to nuclear receptor binding site 1 (NR-1) of the PB-responsive enhancer module (PBREM) of the CYP 2B1gene. The EMSA results showed that PB-induced CAR binding to NR-1 was attenuated by DHA. Taken together, these results suggest that attenuation of CAR translocation and decreased subsequent binding to NR-1 are involved in DHA's down-regulation of PB-induced CYP 2B1 expression

Eukaryotic translation initiation factor 3 subunit e controls intracellular calcium homeostasis by regulation of cav1.2 surface expression.

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Pawel Buda

Full Text Available Inappropriate surface expression of voltage-gated Ca(2+channels (CaV in pancreatic ß-cells may contribute to the development of type 2 diabetes. First, failure to increase intracellular Ca(2+ concentrations at the sites of exocytosis impedes insulin release. Furthermore, excessive Ca(2+ influx may trigger cytotoxic effects. The regulation of surface expression of CaV channels in the pancreatic β-cells remains unknown. Here, we used real-time 3D confocal and TIRFM imaging, immunocytochemistry, cellular fractionation, immunoprecipitation and electrophysiology to study trafficking of L-type CaV1.2 channels upon β-cell stimulation. We found decreased surface expression of CaV1.2 and a corresponding reduction in L-type whole-cell Ca(2+ currents in insulin-secreting INS-1 832/13 cells upon protracted (15-30 min stimulation. This internalization occurs by clathrin-dependent endocytosis and could be prevented by microtubule or dynamin inhibitors. eIF3e (Eukaryotic translation initiation factor 3 subunit E is part of the protein translation initiation complex, but its effect on translation are modest and effects in ion channel trafficking have been suggested. The factor interacted with CaV1.2 and regulated CaV1.2 traffic bidirectionally. eIF3e silencing impaired CaV1.2 internalization, which resulted in an increased intracellular Ca(2+ load upon stimulation. These findings provide a mechanism for regulation of L-type CaV channel surface expression with consequences for β-cell calcium homeostasis, which will affect pancreatic β-cell function and insulin production.

Telomerase Reverse Transcriptase Deficiency Prevents Neointima Formation Through Chromatin Silencing of E2F1 Target Genes.

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Endorf, Elizabeth B; Qing, Hua; Aono, Jun; Terami, Naoto; Doyon, Geneviève; Hyzny, Eric; Jones, Karrie L; Findeisen, Hannes M; Bruemmer, Dennis

2017-02-01

Aberrant proliferation of smooth muscle cells (SMC) in response to injury induces pathological vascular remodeling during atherosclerosis and neointima formation. Telomerase is rate limiting for tissue renewal and cell replication; however, the physiological role of telomerase in vascular diseases remains to be determined. The goal of the present study was to determine whether telomerase reverse transcriptase (TERT) affects proliferative vascular remodeling and to define the molecular mechanism by which TERT supports SMC proliferation. We first demonstrate high levels of TERT expression in replicating SMC of atherosclerotic and neointimal lesions. Using a model of guidewire-induced arterial injury, we demonstrate decreased neointima formation in TERT-deficient mice. Studies in SMC isolated from TERT-deficient and TERT overexpressing mice with normal telomere length established that TERT is necessary and sufficient for cell proliferation. TERT deficiency did not induce a senescent phenotype but resulted in G1 arrest albeit hyperphosphorylation of the retinoblastoma protein. This proliferative arrest was associated with stable silencing of the E2F1-dependent S-phase gene expression program and not reversed by ectopic overexpression of E2F1. Finally, chromatin immunoprecipitation and accessibility assays revealed that TERT is recruited to E2F1 target sites and promotes chromatin accessibility for E2F1 by facilitating the acquisition of permissive histone modifications. These data indicate a previously unrecognized role for TERT in neointima formation through epigenetic regulation of proliferative gene expression in SMC. © 2016 American Heart Association, Inc.

BRCA1-IRIS regulates cyclin D1 expression in breast cancer cells

International Nuclear Information System (INIS)

Nakuci, Enkeleda; Mahner, Sven; DiRenzo, James; ElShamy, Wael M.

2006-01-01

The regulator of cell cycle progression, cyclin D1, is up-regulated in breast cancer cells; its expression is, in part, dependent on ERα signaling. However, many ERα-negative tumors and tumor cell lines (e.g., SKBR3) also show over-expression of cyclin D1. This suggests that, in addition to ERα signaling, cyclin D1 expression is under the control of other signaling pathways; these pathways may even be over-expressed in the ERα-negative cells. We previously noticed that both ERα-positive and -negative cell lines over-express BRCA1-IRIS mRNA and protein. Furthermore, the level of over-expression of BRCA1-IRIS in ERα-negative cell lines even exceeded its over-expression level in ERα-positive cell lines. In this study, we show that: (1) BRCA1-IRIS forms complex with two of the nuclear receptor co-activators, namely, SRC1 and SRC3 (AIB1) in an ERα-independent manner. (2) BRCA1-IRIS alone, or in connection with co-activators, is recruited to the cyclin D1 promoter through its binding to c-Jun/AP1 complex; this binding activates the cyclin D1 expression. (3) Over-expression of BRCA1-IRIS in breast cells over-activates JNK/c-Jun; this leads to the induction of cyclin D1 expression and cellular proliferation. (4) BRCA1-IRIS activation of JNK/c-Jun/AP1 appears to account for this, because in cells that were depleted from BRCA1-IRIS, JNK remained inactive. However, depletion of SRC1 or SRC3 instead reduced c-Jun expression. Our data suggest that this novel signaling pathway links BRCA1-IRIS to cellular proliferation through c-Jun/AP1 nuclear pathway; finally, this culminates in the increased expression of the cyclin D1 gene

Diagnostic usefulness of 18F-FAMT PET and L-type amino acid transporter 1 (LAT1) expression in oral squamous cell carcinoma

International Nuclear Information System (INIS)

Nobusawa, Aiko; Kim, Mai; Kaira, Kyoichi; Miyashita, Go; Negishi, Akihide; Yokoo, Satoshi; Oriuchi, Noboru; Higuchi, Tetsuya; Tsushima, Yoshito; Kanai, Yoshikatsu; Oyama, Tetsunari

2013-01-01

l-[3- 18 F]-α-Methyltyrosine ( 18 F-FAMT) was developed as an amino acid tracer for PET imaging to provide better specificity than 2-[ 18 F]fluoro-2-deoxy-d-glucose ( 18 F-FDG) PET for cancer diagnosis. We investigated the diagnostic usefulness of 18 F-FAMT in oral squamous cell carcinoma (OSCC). The correlation between tumour uptake of 18 F-FAMT and L-type amino acid transporter 1 (LAT1) expression was determined. The study group comprised 68 OSCC patients who underwent both 18 F-FAMT and 18 F-FDG PET. Resected tumour sections were stained by immunohistochemistry for LAT1, CD98 and Ki-67, and microvessel density was determined in terms of CD34 and p53 expression. The sensitivity of primary tumour detection by 18 F-FAMT and 18 F-FDG PET was 98 % and 100 %, respectively. The sensitivity, specificity and accuracy of 18 F-FAMT PET for detecting malignant lymph nodes were 68 %, 99 % and 97 %, respectively, and equivalent values for 18 F-FDG PET were 84 %, 94 % and 94 %, respectively. The specificity and accuracy of 18 F-FAMT were significantly higher than those of 18 F-FDG. The uptake of 18 F-FAMT was significantly correlated with LAT1 expression, cell proliferation and advanced stage. The expression of LAT1 in OSCC cells was closely correlated with CD98 levels, cell proliferation and angiogenesis. 18 F-FAMT PET showed higher specificity for detecting malignant lesions than 18 F-FDG PET. The uptake of 18 F-FAMT by OSCC cells can be determined by the presence of LAT1 expression and tumour cell proliferation. (orig.)

E2F-1-Induced p53-independent apoptosis in transgenic mice

DEFF Research Database (Denmark)

Holmberg, Christian Henrik; Helin, K.; Sehested, M.

1998-01-01

The E2F transcription factors are key targets for the retinoblastoma protein, pRB. By inactivation of E2Fs, pRB prevents progression to the S phase. To test proliferative functions of E2F, we generated transgenic mice expressing human E2F-1 and/or human DP-1. When the hydroxymethyl glutaryl...... involving increased apoptosis in the germinal epithelium. This effect was potentiated by simultaneous overexpression of DP-1. Testicular atrophy as a result of overexpression of E2F-1 and DP-1 is independent of functional p53, since p53-nullizygous transgenic mice overexpressing E2F-1 and DP-1 also suffered...

Distinct Calcium Signaling Pathways Regulate Calmodulin Gene Expression in Tobacco1

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van der Luit, Arnold H.; Olivari, Claudio; Haley, Ann; Knight, Marc R.; Trewavas, Anthony J.

1999-01-01

Cold shock and wind stimuli initiate Ca2+ transients in transgenic tobacco (Nicotiana plumbaginifolia) seedlings (named MAQ 2.4) containing cytoplasmic aequorin. To investigate whether these stimuli initiate Ca2+ pathways that are spatially distinct, stress-induced nuclear and cytoplasmic Ca2+ transients and the expression of a stress-induced calmodulin gene were compared. Tobacco seedlings were transformed with a construct that encodes a fusion protein between nucleoplasmin (a major oocyte nuclear protein) and aequorin. Immunocytochemical evidence indicated targeting of the fusion protein to the nucleus in these plants, which were named MAQ 7.11. Comparison between MAQ 7.11 and MAQ 2.4 seedlings confirmed that wind stimuli and cold shock invoke separate Ca2+ signaling pathways. Partial cDNAs encoding two tobacco calmodulin genes, NpCaM-1 and NpCaM-2, were identified and shown to have distinct nucleotide sequences that encode identical polypeptides. Expression of NpCaM-1, but not NpCaM-2, responded to wind and cold shock stimulation. Comparison of the Ca2+ dynamics with NpCaM-1 expression after stimulation suggested that wind-induced NpCaM-1 expression is regulated by a Ca2+ signaling pathway operational predominantly in the nucleus. In contrast, expression of NpCaM-1 in response to cold shock is regulated by a pathway operational predominantly in the cytoplasm. PMID:10557218

Stat1-independent regulation of gene expression in response to IFN-γ

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Ramana, Chilakamarti V.; Gil, M. Pilar; Han, Yulong; Ransohoff, Richard M.; Schreiber, Robert D.; Stark, George R.

2001-01-01

Although Stat1 is essential for cells to respond fully to IFN-γ, there is substantial evidence that, in the absence of Stat1, IFN-γ can still regulate the expression of some genes, induce an antiviral state and affect cell growth. We have now identified many genes that are regulated by IFN-γ in serum-starved Stat1-null mouse fibroblasts. The proteins induced by IFN-γ in Stat1-null cells can account for the substantial biological responses that remain. Some genes are induced in both wild-type and Stat1-null cells and thus are truly Stat1-independent. Others are subject to more complex regulation in response to IFN-γ, repressed by Stat1 in wild-type cells and activated in Stat1-null cells. Many genes induced by IFN-γ in Stat1-null fibroblasts also are induced by platelet-derived growth factor in wild-type cells and thus are likely to be involved in cell proliferation. In mouse cells expressing the docking site mutant Y440F of human IFN-γ receptor subunit 1, the mouse Stat1 is not phosphorylated in response to human IFN-γ, but c-myc and c-jun are still induced, showing that the Stat1 docking site is not required for Stat1-independent signaling. PMID:11390994

The E2F transcription factors: key regulators of cell proliferation

DEFF Research Database (Denmark)

Müller, H; Helin, K

2000-01-01

Ever since its discovery, the RB-1 gene and the corresponding protein, pRB, have been a focal point of cancer research. The isolation of E2F transcription factors provided the key to our current understanding of RB-1 function in the regulation of the cell cycle and in tumor suppression....... It is becoming more and more evident that the regulatory circuits governing the cell cycle are very complex and highly interlinked. Certain aspects of RB-1 function, for instance its role in differentiation, cannot be easily explained by the current models of pRB-E2F interaction. One reason is that pRB has...

Yersinia Type III Secretion System Master Regulator LcrF

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Schwiesow, Leah; Lam, Hanh

2015-01-01

Many Gram-negative pathogens express a type III secretion (T3SS) system to enable growth and survival within a host. The three human-pathogenic Yersinia species, Y. pestis, Y. pseudotuberculosis, and Y. enterocolitica, encode the Ysc T3SS, whose expression is controlled by an AraC-like master regulator called LcrF. In this review, we discuss LcrF structure and function as well as the environmental cues and pathways known to regulate LcrF expression. Similarities and differences in binding motifs and modes of action between LcrF and the Pseudomonas aeruginosa homolog ExsA are summarized. In addition, we present a new bioinformatics analysis that identifies putative LcrF binding sites within Yersinia target gene promoters. PMID:26644429

Regulation of SFRP-1 expression in the rat dental follicle.

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Liu, Dawen; Yao, Shaomian; Wise, Gary E

2012-01-01

Tooth eruption requires osteoclastogenesis and subsequent bone resorption. Secreted frizzled-related protein-1 (SFRP-1) negatively regulates osteoclastogenesis. Our previous studies indicated that SFRP-1 is expressed in the rat dental follicle (DF), with reduced expression at days 3 and 9 close to the times for the major and minor bursts of osteoclastogenesis, respectively; but it remains unclear as to what molecules contribute to its reduced expression at these critical times. Thus, it was the aim of this study to determine which molecules regulate the expression of SFRP-1 in the DF. To that end, the DF cells were treated with cytokines that are maximally expressed at days 3 or 9, and SFRP-1 expression was determined. Our study indicated that colony-stimulating factor-1 (CSF-1), a molecule maximally expressed in the DF at day 3, down-regulated SFRP-1 expression. As to endothelial monocyte-activating polypeptide II (EMAP-II), a highly expressed molecule in the DF at day 3, it had no effect on the expression of SFRP-1. However, when EMAP-II was knocked down by siRNA, the expression of SFRP-1 was elevated, and this elevated SFRP-1 expression could be reduced by adding recombinant EMAP-II protein. This suggests that EMAP-II maintained a lower level of SFRP-1 in the DF. TNF-α is a molecule maximally expressed at day 9, and this study indicated that it also down-regulated the expression of SFRP-1 in the DF cells. In conclusion, CSF-1 and EMAP-II may contribute to the reduced SFRP-1 expression seen on day 3, while TNF-α may contribute to the reduced SFRP-1 expression at day 9.

Adenovirus E4 open reading frame 4-induced dephosphorylation inhibits E1A activation of the E2 promoter and E2F-1-mediated transactivation independently of the retinoblastoma tumor suppressor protein

DEFF Research Database (Denmark)

Mannervik, M; Fan, S; Ström, A C

1999-01-01

of the viral E4 open reading frame 4 (E4-ORF4) protein. This effect does not to require the retinoblastoma protein that previously has been shown to regulate E2F activity. The inhibitory activity of E4-ORF4 appears to be specific because E4-ORF4 had little effect on, for example, E4-ORF6/7 transactivation......Previous studies have shown that the cell cycle-regulated E2F transcription factor is subjected to both positive and negative control by phosphorylation. Here we show that in transient transfection experiments, adenovirus E1A activation of the viral E2 promoter is abrogated by coexpression...... of the E2 promoter. We further show that the repressive effect of E4-ORF4 on E2 transcription works mainly through the E2F DNA-binding sites in the E2 promoter. In agreement with this, we find that E4-ORF4 inhibits E2F-1/DP-1-mediated transactivation. We also show that E4-ORF4 inhibits E2 mRNA expression...

MUC1-C activates EZH2 expression and function in human cancer cells.

Science.gov (United States)

Rajabi, Hasan; Hiraki, Masayuki; Tagde, Ashujit; Alam, Maroof; Bouillez, Audrey; Christensen, Camilla L; Samur, Mehmet; Wong, Kwok-Kin; Kufe, Donald

2017-08-07

The EZH2 histone methyltransferase is a member of the polycomb repressive complex 2 (PRC2) that is highly expressed in diverse human cancers and is associated with a poor prognosis. MUC1-C is an oncoprotein that is similarly overexpressed in carcinomas and has been linked to epigenetic regulation. A role for MUC1-C in regulating EZH2 and histone methylation is not known. Here, we demonstrate that targeting MUC1-C in diverse human carcinoma cells downregulates EZH2 and other PRC2 components. MUC1-C activates (i) the EZH2 promoter through induction of the pRB→E2F pathway, and (ii) an NF-κB p65 driven enhancer in exon 1. We also show that MUC1-C binds directly to the EZH2 CXC region adjacent to the catalytic SET domain and associates with EZH2 on the CDH1 and BRCA1 promoters. In concert with these results, targeting MUC1-C downregulates EZH2 function as evidenced by (i) global and promoter-specific decreases in H3K27 trimethylation (H3K27me3), and (ii) activation of tumor suppressor genes, including BRCA1. These findings highlight a previously unreported role for MUC1-C in activating EZH2 expression and function in cancer cells.

Post-transcriptional gene expression control by NANOS is up-regulated and functionally important in pRb-deficient cells.

Science.gov (United States)

Miles, Wayne O; Korenjak, Michael; Griffiths, Lyra M; Dyer, Michael A; Provero, Paolo; Dyson, Nicholas J

2014-10-01

Inactivation of the retinoblastoma tumor suppressor (pRb) is a common oncogenic event that alters the expression of genes important for cell cycle progression, senescence, and apoptosis. However, in many contexts, the properties of pRb-deficient cells are similar to wild-type cells suggesting there may be processes that counterbalance the transcriptional changes associated with pRb inactivation. Therefore, we have looked for sets of evolutionary conserved, functionally related genes that are direct targets of pRb/E2F proteins. We show that the expression of NANOS, a key facilitator of the Pumilio (PUM) post-transcriptional repressor complex, is directly repressed by pRb/E2F in flies and humans. In both species, NANOS expression increases following inactivation of pRb/RBF1 and becomes important for tissue homeostasis. By analyzing datasets from normal retinal tissue and pRb-null retinoblastomas, we find a strong enrichment for putative PUM substrates among genes de-regulated in tumors. These include pro-apoptotic genes that are transcriptionally down-regulated upon pRb loss, and we characterize two such candidates, MAP2K3 and MAP3K1, as direct PUM substrates. Our data suggest that NANOS increases in importance in pRb-deficient cells and helps to maintain homeostasis by repressing the translation of transcripts containing PUM Regulatory Elements (PRE). © 2014 The Authors.

XoxF Is Required for Expression of Methanol Dehydrogenase in Methylobacterium extorquens AM1 ▿

Science.gov (United States)

Skovran, Elizabeth; Palmer, Alexander D.; Rountree, Austin M.; Good, Nathan M.; Lidstrom, Mary E.

2011-01-01

In Gram-negative methylotrophic bacteria, the first step in methylotrophic growth is the oxidation of methanol to formaldehyde in the periplasm by methanol dehydrogenase. In most organisms studied to date, this enzyme consists of the MxaF and MxaI proteins, which make up the large and small subunits of this heterotetrameric enzyme. The Methylobacterium extorquens AM1 genome contains two homologs of MxaF, XoxF1 and XoxF2, which are ∼50% identical to MxaF and ∼90% identical to each other. It was previously reported that xoxF is not required for methanol growth in M. extorquens AM1, but here we show that when both xoxF homologs are absent, strains are unable to grow in methanol medium and lack methanol dehydrogenase activity. We demonstrate that these defects result from the loss of gene expression from the mxa promoter and suggest that XoxF is part of a complex regulatory cascade involving the 2-component systems MxcQE and MxbDM, which are required for the expression of the methanol dehydrogenase genes. PMID:21873495

F9 fimbriae of uropathogenic Escherichia coli are expressed at low temperature and recognise Galβ1-3GlcNAc-containing glycans.

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Daniël J Wurpel

Full Text Available Uropathogenic Escherichia coli (UPEC is the leading causative agent of urinary tract infections (UTI in the developed world. Among the major virulence factors of UPEC, surface expressed adhesins mediate attachment and tissue tropism. UPEC strains typically possess a range of adhesins, with type 1 fimbriae and P fimbriae of the chaperone-usher class the best characterised. We previously identified and characterised F9 as a new chaperone-usher fimbrial type that mediates biofilm formation. However, the regulation and specific role of F9 fimbriae remained to be determined in the context of wild-type clinical UPEC strains. In this study we have assessed the distribution and genetic context of the f9 operon among diverse E. coli lineages and pathotypes and demonstrated that f9 genes are significantly more conserved in a UPEC strain collection in comparison to the well-defined E. coli reference (ECOR collection. In the prototypic UPEC strain CFT073, the global regulator protein H-NS was identified as a transcriptional repressor of f9 gene expression at 37°C through its ability to bind directly to the f9 promoter region. F9 fimbriae expression was demonstrated at 20°C, representing the first evidence of functional F9 fimbriae expression by wild-type E. coli. Finally, glycan array analysis demonstrated that F9 fimbriae recognise and bind to terminal Galβ1-3GlcNAc structures.

Sequence Conservation and Sexually Dimorphic Expression of the Ftz-F1 Gene in the Crustacean Daphnia magna.

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Nur Syafiqah Mohamad Ishak

Full Text Available Identifying the genes required for environmental sex determination is important for understanding the evolution of diverse sex determination mechanisms in animals. Orthologs of Drosophila orphan receptor Fushi tarazu factor-1 (Ftz-F1 are known to function in genetic sex determination. In contrast, their roles in environmental sex determination remain unknown. In this study, we have cloned and characterized the Ftz-F1 ortholog in the branchiopod crustacean Daphnia magna, which produces males in response to environmental stimuli. Similar to that observed in Drosophila, D. magna Ftz-F1 (DapmaFtz-F1 produces two splicing variants, αFtz-F1 and βFtz-F1, which encode 699 and 777 amino acids, respectively. Both isoforms share a DNA-binding domain, a ligand-binding domain, and an AF-2 activation domain and differ only at the A/B domain. The phylogenetic position and genomic structure of DapmaFtz-F1 suggested that this gene has diverged from an ancestral gene common to branchiopod crustacean and insect Ftz-F1 genes. qRT-PCR showed that at the one cell and gastrulation stages, both DapmaFtz-F1 isoforms are two-fold more abundant in males than in females. In addition, in later stages, their sexual dimorphic expressions were maintained in spite of reduced expression. Time-lapse imaging of DapmaFtz-F1 RNAi embryos was performed in H2B-GFP expressing transgenic Daphnia, demonstrating that development of the RNAi embryos slowed down after the gastrulation stage and stopped at 30-48 h after ovulation. DapmaFtz-F1 shows high homology to insect Ftz-F1 orthologs based on its amino acid sequence and exon-intron organization. The sexually dimorphic expression of DapmaFtz-F1 suggests that it plays a role in environmental sex determination of D. magna.

Atomic structure of CaF2/MnF2-Si(1 1 1) superlattices from X-ray diffraction

International Nuclear Information System (INIS)

Alcock, Simon G.; Nicklin, C.L.; Howes, P.B.; Norris, C.A.; Kyutt, R.N.; Sokolov, N.S.; Yakovlev, N.L.

2007-01-01

X-ray reflectivity and non-specular crystal truncation rod scans have been used to determine the three-dimensional atomic structure of the buried CaF 2 -Si(1 1 1) interface and ultrathin films of MnF 2 and CaF 2 within a superlattice. We show that ultrathin films of MnF 2 , below a critical thickness of approximately four monolayers, are crystalline, pseudomorphic, and adopt the fluorite structure of CaF 2 . High temperature deposition of the CaF 2 buffer layer produces a fully reacted, CaF 2 -Si(1 1 1) type-B interface. The mature, 'long' interface is shown to consist of a partially occupied layer of CaF bonded to the Si substrate, followed by a distorted CaF layer. Our atomistic, semi-kinematical scattering method extends the slab reflectivity method by providing in-plane structural information

Signaling pathways regulating the expression of Prx1 and Prx2 in the Chick Mandibular Mesenchyme

Science.gov (United States)

Doufexi, Aikaterini-El; Mina, Mina

2009-01-01

Prx1 and Prx2 are members of the aristaless-related homeobox genes shown to play redundant but essential roles in morphogenesis of the mandibular processes. To gain insight into the signaling pathways that regulate expression of Prx genes in the mandibular mesenchyme, we used the chick as a model system. We examined the patterns of gene expression in the face and the roles of signals derived from the epithelium on the expression of Prx genes in the mandibular mesenchyme. Our results demonstrated stage-dependent roles of mandibular epithelium on the expression of Prx in the mandibular mesenchyme and provide evidence for positive roles of members of the fibroblast and hedgehog families derived from mandibular epithelium on the expression of Prx genes in the mandibular mesenchyme. Our studies suggest that endothelin-1 signaling derived from the mesenchyme is involved in restricting the expression of Prx2 to the medial mandibular mesenchyme. PMID:18942149

E2F1 and p53 Transcription Factors as Accessory Factors for Nucleotide Excision Repair

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David G. Johnson

2012-10-01

Full Text Available Many of the biochemical details of nucleotide excision repair (NER have been established using purified proteins and DNA substrates. In cells however, DNA is tightly packaged around histones and other chromatin-associated proteins, which can be an obstacle to efficient repair. Several cooperating mechanisms enhance the efficiency of NER by altering chromatin structure. Interestingly, many of the players involved in modifying chromatin at sites of DNA damage were originally identified as regulators of transcription. These include ATP-dependent chromatin remodelers, histone modifying enzymes and several transcription factors. The p53 and E2F1 transcription factors are well known for their abilities to regulate gene expression in response to DNA damage. This review will highlight the underappreciated, transcription-independent functions of p53 and E2F1 in modifying chromatin structure in response to DNA damage to promote global NER.

Estradiol Receptors Regulate Differential Connexin 43 Expression in F98 and C6 Glioma Cell Lines.

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Zahra Moinfar

Full Text Available Glioma is the most common malignant primary brain tumour with male preponderance and poor prognosis. Glioma cells express variable amounts of connexin 43 (Cx43 and estrogen receptors (ERs. Both, Cx43 and ERs, play important roles in cell proliferation and migration. Therefore, we investigated the effects of 17-ß estradiol (E2 on Cx43 expression in two glioma cell lines with variable native expression of Cx43.F98 and C6 rat glioma cells were cultured for 24 h in the presence of 10 nM or 100 nM E2, and the E2-antagonist, Fulvestrant. An MTT assay was performed to evaluate cell viability. ERα, ERβ and Cx43 protein expressions were analysed by western blotting and Cx43 mRNA expression was analysed by real-time polymerase chain reaction. To quantify cell migration, an exclusive zone migration assay was used. Functional coupling of cells via gap junctions was examined using whole-cell patch-clamp technique.E2 reduced Cx43 expression in C6 cells, but increased Cx43 expression in F98 cultures. These effects were mediated via ERs. Moreover, E2 promoted C6 cell migration, but it did not affect F98 cell migration. The expression level of ERα was found to be high in C6, but low in F98 cells. ERβ was exclusively expressed in C6 cells. In addition, E2 treatment induced a significant decrease of ERβ in C6 cultures, while it decreased ERα expression in F98 glioma cells.These findings show that E2 differentially modulates Cx43 expression in F98 and C6 glioma cells, likely due to the differential expression of ERs in each of these cell lines. Our findings point to the molecular mechanisms that might contribute to the gender-specific differences in the malignancy of glioma and could have implications for therapeutic strategies against glioma.

Efeito de produtos fitossanitários utilizados na cultura do tomateiro (Lycopersicon esculentum Mill. sobre Trichogramma pretiosum Riley, 1879 nas gerações F1 e F2 em ovos de Anagasta kuehniella (Zeller, 1879 Effect of pesticides used on tomato crop (Lycopersicon esculentum Mill. on Trichogramma pretiosum Riley, 1879 in F1 and F2 generations on Anagasta kuehniella (Zeller, 1879 eggs

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Geraldo Andrade Carvalho

2003-04-01

Full Text Available Duas populações de Trichogramma pretiosum Riley, 1879, provenientes de Alegre, ES = L9 e Venda Nova do Imigrante, ES = L10, foram submetidas aos principais produtos fitossanitários utilizados na cultura do tomateiro, após serem multiplicadas em ovos de Anagasta kuehniella (Zeller. Os ovos desse hospedeiro foram tratados e oferecidos ao parasitismo decorridas 0, 24 e 48 horas após o tratamento, e mantidos em câmaras climáticas a 25 ± 2ºC, UR de 60 ± 10% e fotofase de 14 horas. Os inseticidas deltametrina, abamectin e metamidofós, independentemente da linhagem de T. pretiosum, reduziram a longevidade de fêmeas da geração maternal. Triflumuron, clorfluazuron, benomil, clorotalonil, Bacillus thuringiensis, mancozeb, dimetomorf, tebufenozide, teflubenzuron, acefato, pirimicarbe, iprodiona, metamidofós e ciromazina não afetaram a capacidade de parasitismo de T. pretiosum na geração F1, independentemente da origem da população, e não afetaram a porcentagem de emergência dos indivíduos da geração F2, das duas linhagens.Two Trichogramma pretiosum Riley, 1879 populations from Alegre ES = L9 and Venda Nova do Imigrante, ES = L10 (Brazil were treated with the main pesticides used on tomato crop after reared on Anagasta kuehniella (Zeller eggs. The eggs were treated and submitted to parasitism on 0, 24 and 48 hours and kept in climatic chambers at 25 ± 2 ºC, 60 ± 10% RH and 14 hours photophase. The longevity of T. pretiosum (mother females, independently of strain, was decreased for insecticides deltamethrin, abamectin and methamidophos. No influence was detected in the parasitism capacity in F1 generation of T. pretiosum with the products triflumuron, chlorfluazuron, benomyl, chlorotalonil, Bacillus thuringiensis, mancozeb, dimetomorf, tebufenozide, teflubenzuron, acefate, pirimicarb, iprodione, methamidophos and ciromazine, and these compounds did not effected the emergence in F2 generation of this parasitoid, independently of

E2F-6: a novel member of the E2F family is an inhibitor of E2F-dependent transcription

DEFF Research Database (Denmark)

Cartwright, P; Müller, H; Wagener, C

1998-01-01

with E2Fs 1-5, especially within the DNA binding, heterodimerization and marked box domains. Unlike E2Fs 1-5, E2F-6 lacks a transactivation and a pocket protein binding domain, hence, forms a unique third group within the E2F family. E2F-6 is a nuclear protein that can form heterodimers with the DP......The E2F family of transcription factors are essential for the regulation of genes required for appropriate progression through the cell cycle. Five members of the E2F family have been previously reported, namely E2F1-5. All five are key elements in transcriptional regulation of essential genes......, and they can be divided into two functional groups, those that induce S-phase progression when overexpressed in quiescent cells (E2Fs 1-3), and those that do not (E2Fs 4-5). Here, we describe the identification of a novel member of this family, which we refer to as E2F-6. E2F-6 shares significant homology...

Hath1 inhibits proliferation of colon cancer cells probably through up-regulating expression of Muc2 and p27 and down-regulating expression of cyclin D1.

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Zhu, Dai-Hua; Niu, Bai-Lin; Du, Hui-Min; Ren, Ke; Sun, Jian-Ming; Gong, Jian-Ping

2012-01-01

Previous studies showed that Math1 homologous to human Hath1 can cause mouse goblet cells to differentiate. In this context it is important that the majority of colon cancers have few goblet cells. In the present study, the potential role of Hath1 in colon carcinogenesis was investigated. Sections of paraffin-embedded tissues were used to investigate the goblet cell population of normal colon mucosa, mucosa adjacent colon cancer and colon cancer samples from 48 patients. Hath1 and Muc2 expression in these samples were tested by immunohistochemistry, quantitative real-time reverse transcription -PCR and Western blotting. After the recombinant plasmid, pcDNA3.1(+)-Hath1 had been transfected into HT29 colon cancer cells, three clones were selected randomly to test the levels of Hath1 mRNA, Muc2 mRNA, Hath1, Muc2, cyclin D1 and p27 by quantitative real-time reverse transcription-PCR and Western blotting. Moreover, the proliferative ability of HT29 cells introduced with Hath1 was assessed by means of colony formation assay and xenografting. Expression of Hath1, Muc2, cyclin D1 and p27 in the xenograft tumors was also detected by Western blotting. No goblet cells were to be found in colon cancer and levels of Hath1 mRNA and Hath1, Muc2 mRNA and Muc2 were significantly down-regulated. Hath1 could decrease cyclin D1, increase p27 and Muc2 in HT29 cells and inhibit their proliferation. Hath1 may be an anti-oncogene in colon carcinogenesis.

Noncanonical Pathway for Regulation of CCL2 Expression by an mTORC1-FOXK1 Axis Promotes Recruitment of Tumor-Associated Macrophages

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Hirokazu Nakatsumi

2017-11-01

Full Text Available C-C chemokine ligand 2 (CCL2 plays pivotal roles in tumor formation, progression, and metastasis. Although CCL2 expression has been found to be dependent on the nuclear factor (NF-κB signaling pathway, the regulation of CCL2 production in tumor cells has remained unclear. We have identified a noncanonical pathway for regulation of CCL2 production that is mediated by mammalian target of rapamycin complex 1 (mTORC1 but independent of NF-κB. Multiple phosphoproteomics approaches identified the transcription factor forkhead box K1 (FOXK1 as a downstream target of mTORC1. Activation of mTORC1 induces dephosphorylation of FOXK1, resulting in transactivation of the CCL2 gene. Inhibition of the mTORC1-FOXK1 axis attenuated insulin-induced CCL2 production as well as the accumulation of tumor-associated monocytes-macrophages and tumor progression in mice. Our results suggest that FOXK1 directly links mTORC1 signaling and CCL2 expression in a manner independent of NF-κB and that CCL2 produced by this pathway contributes to tumor progression.

Tumor Suppressor RARRES1 Regulates DLG2, PP2A, VCP, EB1, and Ankrd26

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Ziad J. Sahab, Michael D. Hall, Lihua Zhang, Amrita K. Cheema, Stephen W. Byers

2010-01-01

Full Text Available Retinoic Acid Receptor Responder (RARRES1 initially identified as a novel retinoic acid receptor regulated gene in the skin is a putative tumor suppressor of unknown function. RARRES1 was knocked down in immortalized human prostatic epithelial cell line PWR-1E cells and differential protein expression was identified using differential in-gel electrophoresis (DIGE followed by matrix-assisted laser desorption ionization (MALDI mass spectrometry and western Blot analysis excluding highly abundant proteins routinely identified in almost all proteomics projects. Knock-down of RARRES1: 1- down-regulates PP2A, an enzyme involved in the negative regulation of the growth hormone-stimulated signal transduction pathways; 2- down-regulates Valosin-containing protein causing impaired autophagy; 3- up-regulates the tumor suppressor disks large 2; 4- up-regulates Ankrd26 that belongs to the POTE family of genes that are highly expressed in cancer patients with poor outcome; and 5- down-regulates EB1, a protein that is involved in spindle dynamics and chromosome alignment during mitosis.

SKP2 siRNA inhibits the degradation of P27kip1 and down-regulates the expression of MRP in HL-60/A cells.

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Xiao, Jie; Yin, Songmei; Li, Yiqing; Xie, Shuangfeng; Nie, Danian; Ma, Liping; Wang, Xiuju; Wu, Yudan; Feng, Jianhong

2009-08-01

S-phase kinase-associated protein 2 (SKP2) gene is a tumor suppressor gene, and is involved in the ubiquitin-mediated degradation of P27kip1. SKP2 and P27kip1 affect the proceeding and prognosis of leukemia through regulating the proliferation, apoptosis and differentiation of leukemia cells. In this study, we explored the mechanism of reversing of HL-60/A drug resistance through SKP2 down-regulation. HL-60/A cells were nucleofected by Amaxa Nucleofector System with SKP2 siRNA. The gene and protein expression levels of Skp2, P27kip1, and multi-drug resistance associated protein (MRP) were determined by reverse transcription-polymerase chain reaction and western blot analysis, respectively. The cell cycle was analyzed by flow cytometry. The 50% inhibitory concentration value was calculated using cytotoxic analysis according to the death rate of these two kinds of cells under different concentrations of chemotherapeutics to compare the sensitivity of the cells. HL-60/A cells showed multi-drug resistance phenotype characteristic by cross-resistance to adriamycin, daunorubicin, and arabinosylcytosine, due to the expression of MRP. We found that the expression of SKP2 was higher in HL-60/A cells than in HL-60 cells, but the expression of P27kip1 was lower. The expression of SKP2 in HL-60/A cells nucleofected by SKP2 siRNA was down-regulated whereas the protein level of P27kip1 was up-regulated. Compared with the MRP expression level in the control group (nucleofected by control siRNA), the mRNA and protein expression levels of MRP in HL-60/A cells nucleofected by SKP2 siRNA were lower, and the latter cells were more sensitive to adriamycin, daunorubicin, and arabinosylcytosine. Down-regulating the SKP2 expression and arresting cells in the G0/G1 phase improve drug sensitivity of leukemia cells with down-regulated MRP expression.

Snail regulates p21WAF/CIP1 expression in cooperation with E2 A and Twist

International Nuclear Information System (INIS)

Takahashi, Eishi; Funato, Noriko; Higashihori, Norihisa; Hata, Yuiro; Gridley, Thomas; Nakamura, Masataka

2004-01-01

Snail, a zinc-finger transcriptional repressor, is essential for mesoderm and neural crest cell formation and epithelial-mesenchymal transition. The basic helix-loop-helix transcription factors E2A and Twist have been linked with Snail during embryonic development. In this study, we examined the role of Snail in cellular differentiation through regulation of p21 WAF/CIP1 expression. A reporter assay with the p21 promoter demonstrated that Snail inhibited expression of p21 induced by E2A. Co-expression of Snail with Twist showed additive inhibitory effects. Deletion mutants of the p21 promoter revealed that sequences between -270 and -264, which formed a complex with unidentified nuclear factor(s), were critical for E2A and Snail function. The E2A-dependent expression of the endogenous p21 gene was also inhibited by Snail

The inhibition of the mitochondrial F1FO-ATPase activity when activated by Ca2+ opens new regulatory roles for NAD.

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Nesci, Salvatore; Trombetti, Fabiana; Ventrella, Vittoria; Pirini, Maurizio; Pagliarani, Alessandra

2018-01-26

The mitochondrial F1FO-ATPase is uncompetitively inhibited by NAD+ only when the natural cofactor Mg2+ is replaced by Ca2+, a mode putatively involved in cell death. The Ca2+-dependent F1FO-ATPase is also inhibited when NAD+ concentration in mitochondria is raised by acetoacetate. The enzyme inhibition by NAD+ cannot be ascribed to any de-ac(et)ylation or ADP-ribosylation by sirtuines, as it is not reversed by nicotinamide. Moreover, the addition of acetyl-CoA or palmitate, which would favor the enzyme ac(et)ylation, does not affect the F1FO-ATPase activity. Consistently, NAD+ may play a new role, not associated with redox and non-redox enzymatic reactions, in the Ca2+-dependent regulation of the F1FO-ATPase activity.

Mechanisms of a human skeletal myotonia produced by mutation in the C-terminus of NaV1.4: is Ca2+ regulation defective?

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Subrata Biswas

Full Text Available Mutations in the cytoplasmic tail (CT of voltage gated sodium channels cause a spectrum of inherited diseases of cellular excitability, yet to date only one mutation in the CT of the human skeletal muscle voltage gated sodium channel (hNaV1.4F1705I has been linked to cold aggravated myotonia. The functional effects of altered regulation of hNaV1.4F1705I are incompletely understood. The location of the hNaV1.4F1705I in the CT prompted us to examine the role of Ca(2+ and calmodulin (CaM regulation in the manifestations of myotonia. To study Na channel related mechanisms of myotonia we exploited the differences in rat and human NaV1.4 channel regulation by Ca(2+ and CaM. hNaV1.4F1705I inactivation gating is Ca(2+-sensitive compared to wild type hNaV1.4 which is Ca(2+ insensitive and the mutant channel exhibits a depolarizing shift of the V1/2 of inactivation with CaM over expression. In contrast the same mutation in the rNaV1.4 channel background (rNaV1.4F1698I eliminates Ca(2+ sensitivity of gating without affecting the CaM over expression induced hyperpolarizing shift in steady-state inactivation. The differences in the Ca(2+ sensitivity of gating between wild type and mutant human and rat NaV1.4 channels are in part mediated by a divergence in the amino acid sequence in the EF hand like (EFL region of the CT. Thus the composition of the EFL region contributes to the species differences in Ca(2+/CaM regulation of the mutant channels that produce myotonia. The myotonia mutation F1705I slows INa decay in a Ca(2+-sensitive fashion. The combination of the altered voltage dependence and kinetics of INa decay contribute to the myotonic phenotype and may involve the Ca(2+-sensing apparatus in the CT of NaV1.4.

E2F3a gene expression has prognostic significance in childhood acute lymphoblastic leukemia.

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Wang, Kai-Ling; Mei, Yan-Yan; Cui, Lei; Zhao, Xiao-Xi; Li, Wei-Jing; Gao, Chao; Liu, Shu-Guang; Jiao, Ying; Liu, Fei-Fei; Wu, Min-Yuan; Ding, Wei; Li, Zhi-Gang

2014-10-01

To study E2F3a expression and its clinical significance in children with acute lymphoblastic leukemia (ALL). We quantified E2F3a expression at diagnosis in 148 children with ALL by real-time PCR. In the test cohort (n = 48), receiver operating characteristic (ROC) curve was used to find the best cut-off point to divide the patients into E2F3a low- and high-expression groups. The prognostic significance of E2F3a expression was investigated in the test cohort and confirmed in the validation cohort (n = 100). The correlations of E2F3a expression with the clinical features and treatment outcome of these patients were analyzed. ROC curve analysis indicated that the best cut-off point of E2F3a expression was 0.3780. In the test cohort, leukemia-free survival (LFS) and event-free survival (EFS) of the low-expression group were lower than those of the high-expression group (log rank: P = 0.026 for both). This finding was verified in the validation cohort. LFS, EFS, and overall survival were also lower in the low-expression group than in the high-expression group (log rank, P = 0.015, 0.008, and 0.002 respectively). E2F3a low expression was correlated with the existence of BCR-ABL fusion. An algorithm composed of E2F3a expression and minimal residual disease (MRD) could predict relapse or induction failure more precisely than current risk stratification. These results were still significant in the ALL patients without BCR-ABL fusion. Low expression of E2F3a was associated with inferior prognosis in childhood ALL. An algorithm composed of E2F3a expression and MRD could predict relapse or induction failure more precisely than that of the current risk stratification. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Diagnostic usefulness of {sup 18}F-FAMT PET and L-type amino acid transporter 1 (LAT1) expression in oral squamous cell carcinoma

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Nobusawa, Aiko [Gunma University Graduate School of Medicine, Department of Stomatology and Maxillofacial Surgery, Maebashi, Gunma (Japan); Gunma University Graduate School of Medicine, Department of Diagnostic Pathology, Maebashi, Gunma (Japan); Kim, Mai [Gunma University Graduate School of Medicine, Department of Stomatology and Maxillofacial Surgery, Maebashi, Gunma (Japan); Gunma University Graduate School of Medicine, Department of Diagnostic Radiology and Nuclear Medicine, Maebashi, Gunma (Japan); Kaira, Kyoichi [Gunma University Graduate School of Medicine, Department of Diagnostic Pathology, Maebashi, Gunma (Japan); Gunma University Hospital, Oncology Center, Maebashi, Gunma (Japan); Miyashita, Go; Negishi, Akihide; Yokoo, Satoshi [Gunma University Graduate School of Medicine, Department of Stomatology and Maxillofacial Surgery, Maebashi, Gunma (Japan); Oriuchi, Noboru; Higuchi, Tetsuya; Tsushima, Yoshito [Gunma University Graduate School of Medicine, Department of Diagnostic Radiology and Nuclear Medicine, Maebashi, Gunma (Japan); Kanai, Yoshikatsu [Osaka University, Division of Bio-system Pharmacology, Graduate School of Medicine, Osaka (Japan); Oyama, Tetsunari [Gunma University Graduate School of Medicine, Department of Diagnostic Pathology, Maebashi, Gunma (Japan)

2013-10-15

l-[3-{sup 18}F]-{alpha}-Methyltyrosine ({sup 18}F-FAMT) was developed as an amino acid tracer for PET imaging to provide better specificity than 2-[{sup 18}F]fluoro-2-deoxy-d-glucose ({sup 18}F-FDG) PET for cancer diagnosis. We investigated the diagnostic usefulness of {sup 18}F-FAMT in oral squamous cell carcinoma (OSCC). The correlation between tumour uptake of {sup 18}F-FAMT and L-type amino acid transporter 1 (LAT1) expression was determined. The study group comprised 68 OSCC patients who underwent both {sup 18}F-FAMT and {sup 18}F-FDG PET. Resected tumour sections were stained by immunohistochemistry for LAT1, CD98 and Ki-67, and microvessel density was determined in terms of CD34 and p53 expression. The sensitivity of primary tumour detection by {sup 18}F-FAMT and {sup 18}F-FDG PET was 98 % and 100 %, respectively. The sensitivity, specificity and accuracy of {sup 18}F-FAMT PET for detecting malignant lymph nodes were 68 %, 99 % and 97 %, respectively, and equivalent values for {sup 18}F-FDG PET were 84 %, 94 % and 94 %, respectively. The specificity and accuracy of {sup 18}F-FAMT were significantly higher than those of {sup 18}F-FDG. The uptake of {sup 18}F-FAMT was significantly correlated with LAT1 expression, cell proliferation and advanced stage. The expression of LAT1 in OSCC cells was closely correlated with CD98 levels, cell proliferation and angiogenesis. {sup 18}F-FAMT PET showed higher specificity for detecting malignant lesions than {sup 18}F-FDG PET. The uptake of {sup 18}F-FAMT by OSCC cells can be determined by the presence of LAT1 expression and tumour cell proliferation. (orig.)

Ascl1 Coordinately Regulates Gene Expression and the Chromatin Landscape during Neurogenesis

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Alexandre A.S.F. Raposo

2015-03-01

Full Text Available The proneural transcription factor Ascl1 coordinates gene expression in both proliferating and differentiating progenitors along the neuronal lineage. Here, we used a cellular model of neurogenesis to investigate how Ascl1 interacts with the chromatin landscape to regulate gene expression when promoting neuronal differentiation. We find that Ascl1 binding occurs mostly at distal enhancers and is associated with activation of gene transcription. Surprisingly, the accessibility of Ascl1 to its binding sites in neural stem/progenitor cells remains largely unchanged throughout their differentiation, as Ascl1 targets regions of both readily accessible and closed chromatin in proliferating cells. Moreover, binding of Ascl1 often precedes an increase in chromatin accessibility and the appearance of new regions of open chromatin, associated with de novo gene expression during differentiation. Our results reveal a function of Ascl1 in promoting chromatin accessibility during neurogenesis, linking the chromatin landscape at Ascl1 target regions with the temporal progression of its transcriptional program.

Regulation of RNA-dependent RNA polymerase 1 and isochorismate synthase gene expression in Arabidopsis.

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Lydia J R Hunter

Full Text Available RNA-dependent RNA polymerases (RDRs function in anti-viral silencing in Arabidopsis thaliana and other plants. Salicylic acid (SA, an important defensive signal, increases RDR1 gene expression, suggesting that RDR1 contributes to SA-induced virus resistance. In Nicotiana attenuata RDR1 also regulates plant-insect interactions and is induced by another important signal, jasmonic acid (JA. Despite its importance in defense RDR1 regulation has not been investigated in detail.In Arabidopsis, SA-induced RDR1 expression was dependent on 'NON-EXPRESSER OF PATHOGENESIS-RELATED GENES 1', indicating regulation involves the same mechanism controlling many other SA- defense-related genes, including pathogenesis-related 1 (PR1. Isochorismate synthase 1 (ICS1 is required for SA biosynthesis. In defensive signal transduction RDR1 lies downstream of ICS1. However, supplying exogenous SA to ics1-mutant plants did not induce RDR1 or PR1 expression to the same extent as seen in wild type plants. Analysing ICS1 gene expression using transgenic plants expressing ICS1 promoter:reporter gene (β-glucuronidase constructs and by measuring steady-state ICS1 transcript levels showed that SA positively regulates ICS1. In contrast, ICS2, which is expressed at lower levels than ICS1, is unaffected by SA. The wound-response hormone JA affects expression of Arabidopsis RDR1 but jasmonate-induced expression is independent of CORONATINE-INSENSITIVE 1, which conditions expression of many other JA-responsive genes. Transiently increased RDR1 expression following tobacco mosaic virus inoculation was due to wounding and was not a direct effect of infection. RDR1 gene expression was induced by ethylene and by abscisic acid (an important regulator of drought resistance. However, rdr1-mutant plants showed normal responses to drought.RDR1 is regulated by a much broader range of phytohormones than previously thought, indicating that it plays roles beyond those already suggested in virus

MiR-205-5p and miR-342-3p cooperate in the repression of the E2F1 transcription factor in the context of anticancer chemotherapy resistance

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Lai, Xin; Gupta, Shailendra K; Schmitz, Ulf; Marquardt, Stephan; Knoll, Susanne; Spitschak, Alf; Wolkenhauer, Olaf; Pützer, Brigitte M; Vera, Julio

2018-01-01

High rates of lethal outcome in tumour metastasis are associated with the acquisition of invasiveness and chemoresistance. Several clinical studies indicate that E2F1 overexpression across high-grade tumours culminates in unfavourable prognosis and chemoresistance in patients. Thus, fine-tuning the expression of E2F1 could be a promising approach for treating patients showing chemoresistance. Methods: We integrated bioinformatics, structural and kinetic modelling, and experiments to study cooperative regulation of E2F1 by microRNA (miRNA) pairs in the context of anticancer chemotherapy resistance. Results: We showed that an enhanced E2F1 repression efficiency can be achieved in chemoresistant tumour cells through two cooperating miRNAs. Sequence and structural information were used to identify potential miRNA pairs that can form tertiary structures with E2F1 mRNA. We then employed molecular dynamics simulations to show that among the identified triplexes, miR-205-5p and miR-342-3p can form the most stable triplex with E2F1 mRNA. A mathematical model simulating the E2F1 regulation by the cooperative miRNAs predicted enhanced E2F1 repression, a feature that was verified by in vitro experiments. Finally, we integrated this cooperative miRNA regulation into a more comprehensive network to account for E2F1-related chemoresistance in tumour cells. The network model simulations and experimental data indicate the ability of enhanced expression of both miR-205-5p and miR-342-3p to decrease tumour chemoresistance by cooperatively repressing E2F1. Conclusions: Our results suggest that pairs of cooperating miRNAs could be used as potential RNA therapeutics to reduce E2F1-related chemoresistance. PMID:29464002

N-Myc Differentially Regulates Expression of MXI1 Isoforms in Neuroblastoma1

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Armstrong, Michael B; Mody, Rajen J; Ellis, D Christian; Hill, Adam B; Erichsen, David A; Wechsler, Daniel S

2013-01-01

Amplification of the MYCN proto-oncogene is associated with a poor prognosis in patients with metastatic neuroblastoma (NB). MYCN encodes the N-Myc protein, a transcriptional regulator that dimerizes with the Max transcription factor, binds to E-box DNA sequences, and regulates genes involved in cell growth and apoptosis. Overexpression of N-Myc leads to transcriptional activation and an increase in NB cell proliferation. Mxi1, a member of the Myc family of transcriptional regulators, also binds to Max. However, Mxi1 is a transcriptional repressor and inhibits proliferation of NB cells, suggesting that Mxi1 functions as an N-Myc antagonist. Our laboratory previously identified Mxi1-0, an alternatively transcribed Mxi1 isoform. Mxi1-0 has properties distinct from those of Mxi1; in contrast to Mxi1, Mxi1-0 is unable to suppress c-Myc-dependent transcription. We now show that Mxi1-0 expression increases in response to MYCN overexpression in NB cells, with a positive correlation between MYCN and MXI1-0 RNA levels. We also show that N-Myc expression differentially regulates the MXI1 and MXI1-0 promoters: Increased MYCN expression suppresses MXI1 promoter activity while enhancing transcription through the MXI1-0 promoter. Finally, induction of Mxi1-0 leads to increased proliferation, whereas expression of Mxi1 inhibits cell growth, indicating differential roles for these two proteins. These data suggest that N-Myc differentially regulates the expression of MXI1 and MXI1-0 and can alter the balance between the two transcription factors. Furthermore, MXI1-0 appears to be a downstream target of MYCN-dependent signaling pathways and may contribute to N-Myc-dependent cell growth and proliferation. PMID:24403858

Nidogen-1 regulates laminin-1-dependent mammary-specific gene expression