Molecular regulation of the endothelin-1 gene by hypoxia - Contributions of hypoxia-inducible factor-1, activator protein-1, GATA-2, and p300/CBP
Molecular regulation of the endothelin-1 gene by hypoxia - Contributions of hypoxia-inducible factor-1, activator protein-1, GATA-2, and p300/CBP
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DOI：
10.1074/jbc.m011344200
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发表时间：
2001-04-20
影响因子：
4.8
通讯作者：
Webster, KA
中科院分区：
文献类型：
--
作者：
Yamashita, K;Discher, DJ;Webster, KA
内皮素-1 （ET-1）是一种主要由血管内皮细胞合成和分泌的具有强效血管收缩特性的肽激素。它的产生受到包括缺血和缺氧在内的多种刺激的调节，心肌缺血时其水平的提高可能导致心力衰竭的进展。我们之前报道了人类ET-1启动子中缺氧诱导因子-1 （HIF-1）结合位点的初步表征，该位点有助于激活内皮细胞中ET-1的表达。我们在这里报道，HIF-1结合位点本身不足以引起对缺氧的反应，而是需要额外的50个碱基对的侧链序列，其中包括因子激活蛋白-1 （AP-1）、GATA-8和caat -结合因子（NF-I）的结合位点，这些位点或HIF-1位点的任何一个突变都会消除缺氧的诱导，AP-1和GATA-2位点的突变，但HIF-1位点不存在，通过过表达AP-1、GATA-2、HIF-1 α来补充。体外结合研究证实了GATA-8、AP-1和HIF-1因子之间的物理关联。p300/CBP的过表达或缺失调节了ET-1启动子的表达水平以及内源性ET-1转录物的水平，但在两种情况下都没有改变缺氧诱导的折叠。在非内皮细胞中，缺氧对ET-1启动子的调节需要过表达GATA-2和HIF-1 α。这些结果支持AP-1、GATA-2和NF-1在稳定HIF-1结合和促进p300/CBP向ET-1缺氧反应复合体募集中的重要作用。
Endothelin-1 (ET-1) is a peptide hormone with potent vasoconstrictor properties which is synthesized and secreted predominantly by vascular endothelial cells. Its production is regulated by numerous stimuli including ischemia and hypoxia, and the enhanced levels that occur during myocardial ischemia may contribute to the progression of heart failure. We reported previously a preliminary characterization of a hypoxia-inducible factor-1 (HIF-1) binding site in the human ET-1 promoter which contributed to the activation of ET-1 expression in endothelial cells. We report here that the HIF-1 binding site alone is not sufficient for the response to hypoxia but requires an additional 50 base pairs of flanking sequence that includes binding sites for the factors activator protein-1 (AP-1), GATA-8, and CAAT-binding factor (NF-I), Mutation of any one of these sites or the HIF-1 site eliminated induction by hypoxia, Mutations of the AP-1 and GATA-2 sites, but not the HIF-1 site, were complemented by overexpressing AP-1, GATA-2, HIF-1 alpha, or the activator protein p300/CBP, restoring the response to hypoxia, Binding studies in vitro confirmed physical associations among GATA-8, AP-1, and HIF-1 factors. Overexpression or depletion of p300/CBP modulated the level of ET-1 promoter expression as well as the endogenous ET-I transcript but did not change the fold induction by hypoxia in either case. Regulation of the ET-1 promoter by hypoxia in non-endothelial cells required overexpression of GATA-2 and HIF-1 alpha. The results support essential roles for AP-1, GATA-2, and NF-1 in stabilizing the binding of HIF-1 and promoting recruitment of p300/CBP to the ET-1 hypoxia response complex.