title: Hypoxia-inducible factor 1-mediated human GATA1 induction promotes erythroid differentiation under hypoxic conditions.
abstract: Hypoxia-inducible factor promotes erythropoiesis through coordinated cell type-specific hypoxia responses. GATA1 is essential to normal erythropoiesis and plays a crucial role in erythroid differentiation. In this study, we show that hypoxia-induced GATA1 expression is mediated by HIF1 in erythroid cells. Under hypoxic conditions, significantly increased GATA1 mRNA and protein levels were detected in K562 cells and erythroid induction cultures of CD34(+)  haematopoietic stem/progenitor cells. Enforced HIF1α expression increased GATA1 expression, while HIF1α knockdown by RNA interference decreased GATA1 expression. In silico analysis revealed one potential hypoxia response element (HRE). The results from reporter gene and mutation analysis suggested that this element is necessary for hypoxic response. Chromatin immunoprecipitation (ChIP)-PCR showed that the putative HRE was recognized and bound by HIF1 in vivo. These results demonstrate that the up-regulation of GATA1 during hypoxia is directly mediated by HIF1.The mRNA expression of some erythroid differentiation markers was increased under hypoxic conditions, but decreased with RNA interference of HIF1α or GATA1. Flow cytometry analysis also indicated that hypoxia, desferrioxamine or CoCl(2)  induced expression of erythroid surface markers CD71 and CD235a, while expression repression of HIF1α or GATA1 by RNA interference led to a decreased expression of CD235a. These results suggested that HIF1-mediated GATA1 up-regulation promotes erythropoiesis in order to satisfy the needs of an organism under hypoxic conditions.
authors: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors: Feng-Lin
authors: FL
authors: Zhang
authors: Guo-Min
authors: GM
authors: Shen
authors: Xiao-Ling
authors: XL
authors: Liu
authors: Fang
authors: F
authors: Wang
authors: Ying-Ze
authors: YZ
authors: Zhao
authors: Jun-Wu
authors: JW
authors: Zhang
mesh_terms: D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics*; D015687:Cell Hypoxia / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D041905:Erythroid Cells / Q000166:cytology* / Q000378:metabolism*; D005434:Flow Cytometry; D050982:GATA1 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D020014:K562 Cells; D061986:MCF-7 Cells; D008969:Molecular Sequence Data; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D020218:Response Elements / Q000235:genetics
chemical_list: D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger