Genome-wide HIF-1 binding sites in HepG2 cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE16347 | GEO | 2009/06/02
SECONDARY ACCESSION(S): PRJNA116341
REPOSITORIES: GEO
Similar Datasets
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
Project description:HIF-1 regulated VEGF expression were upregulated in reponse to ischemic injury. However, the VEGF mRNA level were increased in the early stage but decreased in the late stage of myocardial infarction. We found that activities of HIF-1 binding to the HRE sites were possiblely responsible for the differential expression of VEGF. The HIF-1 binding activities were regulated by copper. After ischemic injury, copper concentrations were decreased in the infarct myocardium in the late stage of myocardial infarction, which might reduce VEGF expression through insufficient HIF-1 binding to HRE sites.
2022-01-24 | GSE125755 | GEO
Project description:Hypoxia-Inducible Factor 1 (HIF-1) plays a key role in cellular adaptation to hypoxia. To better understand the determinants of HIF-1 binding and transactivation, we used ChIP-chip and gene expression profiling to define the relationship between the epigenetic landscape, sites of HIF-1 binding, and genes transactivated by hypoxia in two cell lines, HepG2 hepatoma cell line and U87 glioma cell line.
2009-10-09 | GSE18499 | GEO
Project description:Transcription factors (TFs) are classically attributed a modular construction, containing well-structured sequence specific DNA-binding domains (DBDs) paired with disordered activation domains (ADs) responsible for protein-protein interactions targeting cofactors or the core transcription initiation machinery. However, this simple division of labor model struggles to explain why TFs with identical DNA binding sequence specificity determined in vitro exhibit distinct binding profiles in vivo. The family of Hypoxia-Inducible Factors (HIFs) offer a stark example: aberrantly expressed in several cancer types, HIF-1α and HIF-2α subunit isoforms recognize the same DNA motif in vitro – the hypoxia response element (HRE) – but only share a subset of their target genes in vivo, while eliciting contrasting effects on cancer development and progression under certain circumstances. To probe the mechanisms mediating isoform-specific gene regulation, we used live cell single particle tracking (SPT) to investigate HIF nuclear dynamics and how they change upon genetic perturbation or drug treatment. We found that HIF-α subunits and their dimerization partner HIF-1β exhibit distinct diffusion and binding characteristics that are exquisitely sensitive to concentration and subunit stoichiometry. Using domain-swap variants, mutations, and a HIF-2α specific inhibitor, we found that although the DBD and dimerization domains are important, a major determinant of chromatin binding and diffusion behavior is dictated by the AD-containing intrinsically disordered regions (IDR). Using orthogonal genomic approaches such as Cut-and-Run and RNA-seq, we also confirmed IDR-dependent binding and activation for a specific subset of HIF-target genes. These findings reveal a previously unappreciated role of IDRs in regulating the TF search process that may play a role in selective functional target site binding on chromatin.
2022-07-08 | GSE207574 | GEO
Project description:Transcription factors (TFs) are classically attributed a modular construction, containing well-structured sequence specific DNA-binding domains (DBDs) paired with disordered activation domains (ADs) responsible for protein-protein interactions targeting cofactors or the core transcription initiation machinery. However, this simple division of labor model struggles to explain why TFs with identical DNA binding sequence specificity determined in vitro exhibit distinct binding profiles in vivo. The family of Hypoxia-Inducible Factors (HIFs) offer a stark example: aberrantly expressed in several cancer types, HIF-1α and HIF-2α subunit isoforms recognize the same DNA motif in vitro – the hypoxia response element (HRE) – but only share a subset of their target genes in vivo, while eliciting contrasting effects on cancer development and progression under certain circumstances. To probe the mechanisms mediating isoform-specific gene regulation, we used live cell single particle tracking (SPT) to investigate HIF nuclear dynamics and how they change upon genetic perturbation or drug treatment. We found that HIF-α subunits and their dimerization partner HIF-1β exhibit distinct diffusion and binding characteristics that are exquisitely sensitive to concentration and subunit stoichiometry. Using domain-swap variants, mutations, and a HIF-2α specific inhibitor, we found that although the DBD and dimerization domains are important, a major determinant of chromatin binding and diffusion behavior is dictated by the AD-containing intrinsically disordered regions (IDR). Using orthogonal genomic approaches such as Cut-and-Run and RNA-seq, we also confirmed IDR-dependent binding and activation for a specific subset of HIF-target genes. These findings reveal a previously unappreciated role of IDRs in regulating the TF search process that may play a role in selective functional target site binding on chromatin.
2022-07-08 | GSE207573 | GEO
Project description:Hypoxia inducible factor (HIF) is the major transcriptional regulator of cellular responses to hypoxia. The two principal HIF-a isoforms, HIF-1a and HIF-2a, are progressively stabilized in response to hypoxia and form heterodimers with HIF-1b to activate a broad range of transcriptional responses. Here we report on the pan-genomic distribution of isoform-specific HIF binding in response to hypoxia of varying severity and duration, and in response to genetic ablation of each HIF-a isoform. Our findings reveal that, despite an identical consensus recognition sequence in DNA, each HIF heterodimer loads progressively at a distinct repertoire of cell-type specific sites across the genome, with little evidence of redistribution under any of the conditions examined. Marked biases towards promoter proximal binding of HIF-1 and promoter distant binding of HIF-2 were observed under all conditions and were consistent in multiple cell type. The findings imply that each HIF isoform has an inherent property that determines its binding distribution across the genome, which might be exploited to therapeutically target the specific transcriptional output of each isoform independently.
2018-10-06 | GSE120886 | GEO
Project description:Hypoxia inducible factor (HIF) is the major transcriptional regulator of cellular responses to hypoxia. The two principal HIF-a isoforms, HIF-1a and HIF-2a, are progressively stabilized in response to hypoxia and form heterodimers with HIF-1b to activate a broad range of transcriptional responses. Here we report on the pan-genomic distribution of isoform-specific HIF binding in response to hypoxia of varying severity and duration, and in response to genetic ablation of each HIF-a isoform. Our findings reveal that, despite an identical consensus recognition sequence in DNA, each HIF heterodimer loads progressively at a distinct repertoire of cell-type specific sites across the genome, with little evidence of redistribution under any of the conditions examined. Marked biases towards promoter proximal binding of HIF-1 and promoter distant binding of HIF-2 were observed under all conditions and were consistent in multiple cell type. The findings imply that each HIF isoform has an inherent property that determines its binding distribution across the genome, which might be exploited to therapeutically target the specific transcriptional output of each isoform independently.
2018-10-06 | GSE120885 | 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. Keywords: Gene expression changes in cultured U251 cells after DFO-stimulation and various treatment conditions
2007-05-17 | GSE7835 | GEO
Project description:Neuroendocrine (NE) carcinoma and NE differentiation (NED) of human prostate tumor are hallmarks of aggressive human prostate cancer. Here we reveal that HIF-1a cooperation with FoxA2, a transcription factor expressed in NE tissue, is required for determining NE phenotype. Reduced HIF-1a expression, as seen in the E3 ubiquitin ligase Siah2 mutant mice, converted NE tumors to atypical hyperplasia when crossed with the TRAMPTg mice. Significantly, HIF-1a cooperation with FoxA2 enables the trans-activation of select HRE-regulated genes such as Hes6, Plod2 and Jmjd1a, whose expression is notably higher in metastatic prostate adenocarcinomas. Our findings disclose the requirement for spatial and timely regulation of FoxA2 and HIF-1a for NE/NED in prostate tumors. 12 prostate tumor samples were analyzed during normoxia and hypoxia, with different FOX/HIF genotypes. The pivotal samples are represented as duplicates.
2010-07-13 | E-GEOD-18478 | biostudies-arrayexpress
Project description:Background: Tibetan chicken, a unique plateau breed, has a suite of adaptive features that enable it to tolerate the high-altitude hypoxic environment. HIF‐1α (hypoxia inducible factor 1 subunit alpha) is a crucial mediator of the cellular response to hypoxia. HIF‐1α maintains oxygen homeostasis by inducing glycolysis, erythropoiesis, and angiogenesis; however, the target genes involved in adaptive responses to hypoxia in animals and birds of plateaus are still unclear. Results: We used ChIP-seq to map HIF‐1α binding regions in chorioallantoic membrane (CAM) tissue of chicken embryos, and identified 752 HIF-1α target genes (TG), of which 112 were differentially expressed target genes (DTGs) between the two breeds. We found that eight genes (PTK2, GPNMB, CALD1, SLC25A1, SPRY2, NUPL2, RANBPL, and CBWD1) play important roles in hypoxic adaption by regulating blood vessel development, energy metabolism through angiogenesis, vascular smooth muscle contraction, and various hypoxia-related signaling pathways (including VEGF and MAPK) in Tibetan chickens during embryonic development. Conclusions: This study enhances our understanding of the molecular mechanisms of hypoxic adaptation in Tibetan chickens and provides new insights into adaptation to hypoxia in humans and other species living at high altitude.
2019-09-12 | GSE137302 | GEO