Overexpression of the long Hypoxia inducible factor (HIF)-3a2 splice variant under 1 % hypoxia in Hep3B cells
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PROVIDER: PRJNA529070 | ENA |
REPOSITORIES: ENA
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Project description:The human HIF3A gene undergoes extensive alternative splicing resulting in seven known isoforms. The short splice variant, HIF-3alpha4, is an inhibitor of the hypoxia response driven by HIF-1 and HIF-2. The role of the long isoforms remains unclear. We used cDNA microarray to study the overall impact of HIF-3a2 overexpression in Hep3B cells under 1 % hypoxia.
2019-12-31 | GSE128845 | GEO
Project description:Hypoxia-inducible factor (HIF), an αβ dimer, is the master regulator of oxygen homeostasis. HIF induces the expression of several hundred genes under hypoxic conditions. Three HIF isoforms differing in the oxygen-sensitive α subunit exist in vertebrates. While HIF-1 and HIF-2 are known transcription activators, HIF-3 has been considered as a negative regulator of the hypoxia response pathway by formation of inactive dimers between the HIF-3α and HIF-1α or HIF-2α subunit. However, the human HIF3A mRNA is subject to complex alternative splicing, which leads to production of both long and short HIF-3α variants. It has been shown recently that the long HIF-3α variants can form αβ dimers that possess transcriptional activation capacity, while the short splice variant inhibits hypoxia-inducible gene expression. Chromatin immunoprecipitation analyses of HIF-3α2 overexpression in Hep3B cells show that HIF-3α2 binding associates with canonical hypoxia response elements (5'-RCGTG-3') in the promoter regions of the erythropoietin (EPO) gene among others. Luciferase reporter assays show that the identified HIF-3α2 chromatin-binding regions are sufficient to promote transcription by HIF-3α2 and HIF-1. Furthermore, HIF-3α2 overexpression and knock-down studies by siRNA targeting the HIF3A gene show that EPO mRNA and protein levels are upregulated and downregulated, respectively. Taken together, the results show that HIF-3α2 is a transcription activator that is directly involved in erythropoietin signaling.
2019-12-31 | GSE129491 | GEO
Project description:The human HIF3A gene undergoes extensive alternative splicing resulting in seven known isoforms. The short splice variant, HIF-3alpha4, is an inhibitor of the hypoxia response driven by HIF-1 and HIF-2. The role of the long isoforms remains unclear. We used cDNA microarray to study the overall impact of HIF3A knock-down by transfecting Hep3B cells with siRNA targeting a region shared by all splice variants under 1 % hypoxia.
2019-12-31 | GSE128846 | GEO
Project description:Alternative RNA splicing analysis in Hep3B cell cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen Hypoxia is a common characteristic of many solid tumors. The hypoxic microenvironment stabilizes hypoxia-inducible transcription factor 1? (HIF1?) and 2? (HIF2?) to activate gene transcription, which promotes tumor cell survival. 95% of human genes are alternatively spliced, producing RNA isoforms that code functionally distinct proteins. Thus, effective hypoxia response requires increased HIF target gene transcription as well as proper RNA splicing of these HIF target genes. However, it is unclear if and how hypoxia regulates RNA splicing of HIF target genes. This study determined the effects of hypoxia on alternative splicing (AS) of HIF and non-HIF target genes in Hep3B cells and characterized the role of HIF in regulating AS of HIF induced genes. The results indicated that hypoxia generally promotes exon inclusion for hypoxia-induced, but reduces exon inclusion for hypoxia reduced genes. Mechanistically, HIF activity, but not hypoxia per se is found to be necessary and sufficient to increase exon inclusion of several HIF target genes including pyruvate dehydrogenase kinase 1 (PDK1). PDK1 splicing reporters confirmed that transcriptional activation by HIF is sufficient to increase exon inclusion of PDK1 splicing reporter. In contrast, transcriptional activation of the PDK1 minigene by other transcription factor in the absence of endogenous HIF target gene activation fails to alter PDK1 RNA splicing, demonstrating a novel role of HIF target gene(s) in regulating RNA splicing of HIF target genes. Implications:This study demonstrates a novel function of HIF in regulating RNA splicing of HIF target genes. We analyzed total RNA from Hep3B cells cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen using the Affymetrix Human Exon 1.0 ST platform. Array data was processed by Altanalyze software version 2.0.7. Techinical replicates were performed for Nx and Hx treated Hep3B cells
2014-05-14 | E-GEOD-57613 | biostudies-arrayexpress
Project description:Alternative RNA splicing analysis in Hep3B cell cultured under 21% (N1,3,5) or 1.2% (H2,4,6) oxygen Hypoxia is a common characteristic of many solid tumors. The hypoxic microenvironment stabilizes hypoxia-inducible transcription factor 1α (HIF1α) and 2α (HIF2α) to activate gene transcription, which promotes tumor cell survival. 95% of human genes are alternatively spliced, producing RNA isoforms that code functionally distinct proteins. Thus, effective hypoxia response requires increased HIF target gene transcription as well as proper RNA splicing of these HIF target genes. However, it is unclear if and how hypoxia regulates RNA splicing of HIF target genes. This study determined the effects of hypoxia on alternative splicing (AS) of HIF and non-HIF target genes in Hep3B cells and characterized the role of HIF in regulating AS of HIF induced genes. The results indicated that hypoxia generally promotes exon inclusion for hypoxia-induced, but reduces exon inclusion for hypoxia reduced genes. Mechanistically, HIF activity, but not hypoxia per se is found to be necessary and sufficient to increase exon inclusion of several HIF target genes including pyruvate dehydrogenase kinase 1 (PDK1). PDK1 splicing reporters confirmed that transcriptional activation by HIF is sufficient to increase exon inclusion of PDK1 splicing reporter. In contrast, transcriptional activation of the PDK1 minigene by other transcription factor in the absence of endogenous HIF target gene activation fails to alter PDK1 RNA splicing, demonstrating a novel role of HIF target gene(s) in regulating RNA splicing of HIF target genes. Implications:This study demonstrates a novel function of HIF in regulating RNA splicing of HIF target genes.
2014-05-14 | GSE57613 | GEO
Project description:HIF-3α2 overexpression ChIP-seq in Hep3B cells and 1 % hypoxia
| PRJNA531484 | ENA
Project description:Transcription mediated by hypoxia inducible factor (HIF-1) contributes to tumor angiogenesis and metastasis but is also involved in the activation of cell-death pathways and normal physiological processes. Given the complexity of HIF-1 signaling it could be advantageous to target a subset of HIF-1 effectors rather than the entire pathway. We compared the genome-wide effects of three molecules that each interfere with the HIF-1-DNA interaction: a polyamide targeted to the hypoxia response element (HRE), siRNA targeted to HIF-1α, and echinomycin, a DNA binding natural product with a similar but less specific sequence preference to the polyamide. The polyamide affects a subset of hypoxia-induced genes that are consistent with the binding site preferences of the polyamide. For comparison, siRNA targeted to HIF-1α and echinomycin each affect the expression of nearly every gene induced by hypoxia. Remarkably, the total number of genes affected by either polyamide or HIF-1α siRNA over a range of thresholds is comparable. The data shows how polyamides can be used to affect a subset of a pathway regulated by a transcription factor. In addition, this study offers a unique comparison of three complementary approaches towards exogenous control of endogenous gene expression. Keywords: Gene expression changes in cultured U251 cells after DFO-stimulation and various treatment conditions
2007-05-17 | GSE7835 | GEO
Project description:The effects of constitutively active Hypoxia Inducible Factor (HIF) and inactivated von Hippel-Lindau tumor suppressor gene product (pVHL) were examined in a mouse model. Conditionally expressed, constitutively active HIF-1a and HIF-2a were compared with inactivated pVHL.
2006-09-21 | E-MEXP-856 | biostudies-arrayexpress
Project description:Gene expression profiling of primary mouse articular chondrocyte infected with recombinant adenovirus expressing the hypoxia inducible factor-2 alpha (HIF-2α) protein. In this study, we have attempted to explore the effects of HIF-2α overexpression on mouse transcriptome and have identified numerous genes which are involved in osteoarthritis pathogenesis.
2017-10-10 | GSE104794 | GEO
Project description:Transcription mediated by hypoxia inducible factor (HIF-1) contributes to tumor angiogenesis and metastasis but is also involved in the activation of cell-death pathways and normal physiological processes. Given the complexity of HIF-1 signaling it could be advantageous to target a subset of HIF-1 effectors rather than the entire pathway. We compared the genome-wide effects of three molecules that each interfere with the HIF-1-DNA interaction: a polyamide targeted to the hypoxia response element (HRE), siRNA targeted to HIF-1α, and echinomycin, a DNA binding natural product with a similar but less specific sequence preference to the polyamide. The polyamide affects a subset of hypoxia-induced genes that are consistent with the binding site preferences of the polyamide. For comparison, siRNA targeted to HIF-1α and echinomycin each affect the expression of nearly every gene induced by hypoxia. Remarkably, the total number of genes affected by either polyamide or HIF-1α siRNA over a range of thresholds is comparable. The data shows how polyamides can be used to affect a subset of a pathway regulated by a transcription factor. In addition, this study offers a unique comparison of three complementary approaches towards exogenous control of endogenous gene expression. Experiment Overall Design: Hypoxia-mimetic DFO (deferoxamine)-stimulated U251 cells that were treated with polyamide 1, HIF-1α siRNA, and echinomycin were compared to control cells that were also DFO-stimulated. Cells not stimulated with DFO were also compared to the DFO-stimulated controls. Three biological replicates were included for each treatment/condition.
2008-06-15 | E-GEOD-7835 | biostudies-arrayexpress