STAT3 or USF2 contributes to HIF target gene specificity
| Autor: | Matthew R. Pawlus, Cheng-Jun Hu, Guanhai Dai, Aya Murakami, Liyi Wang |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
STAT3 Transcription Factor
USF2 lcsh:Medicine RNA polymerase II Biology Cell Line 03 medical and health sciences 0302 clinical medicine Genes Reporter Gene expression Basic Helix-Loop-Helix Transcription Factors Humans Binding site lcsh:Science Hypoxia Promoter Regions Genetic Gene Transcription factor 030304 developmental biology 0303 health sciences Reporter gene Multidisciplinary Binding Sites Reverse Transcriptase Polymerase Chain Reaction lcsh:R Promoter Hypoxia-Inducible Factor 1 alpha Subunit Molecular biology 030220 oncology & carcinogenesis biology.protein Upstream Stimulatory Factors lcsh:Q RNA Polymerase II Research Article |
| Zdroj: | PLoS ONE PLoS ONE, Vol 8, Iss 8, p e72358 (2013) |
| ISSN: | 1932-6203 |
| Popis: | The HIF1- and HIF2-mediated transcriptional responses play critical roles in solid tumor progression. Despite significant similarities, including their binding to promoters of both HIF1 and HIF2 target genes, HIF1 and HIF2 proteins activate unique subsets of target genes under hypoxia. The mechanism for HIF target gene specificity has remained unclear. Using siRNA or inhibitor, we previously reported that STAT3 or USF2 is specifically required for activation of endogenous HIF1 or HIF2 target genes. In this study, using reporter gene assays and chromatin immuno-precipitation, we find that STAT3 or USF2 exhibits specific binding to the promoters of HIF1 or HIF2 target genes respectively even when over-expressed. Functionally, HIF1α interacts with STAT3 to activate HIF1 target gene promoters in a HIF1α HLH/PAS and N-TAD dependent manner while HIF2α interacts with USF2 to activate HIF2 target gene promoters in a HIF2α N-TAD dependent manner. Physically, HIF1α HLH and PAS domains are required for its interaction with STAT3 while both N- and C-TADs of HIF2α are involved in physical interaction with USF2. Importantly, addition of functional USF2 binding sites into a HIF1 target gene promoter increases the basal activity of the promoter as well as its response to HIF2+USF2 activation while replacing HIF binding site with HBS from a HIF2 target gene does not change the specificity of the reporter gene. Importantly, RNA Pol II on HIF1 or HIF2 target genes is primarily associated with HIF1α or HIF2α in a STAT3 or USF2 dependent manner. Thus, we demonstrate here for the first time that HIF target gene specificity is achieved by HIF transcription partners that are required for HIF target gene activation, exhibit specific binding to the promoters of HIF1 or HIF2 target genes and selectively interact with HIF1α or HIF2α protein. |
| Databáze: | OpenAIRE |
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