Potentiation of human estrogen receptor alpha-mediated gene expression by steroid receptor coactivator-1 (SRC-1) in Saccharomyces cerevisiae.
Potentiation of human estrogen receptor alpha-mediated gene expression by steroid receptor coactivator-1 (SRC-1) in Saccharomyces cerevisiae.
复制标题
酿酒酵母中类固醇受体辅激活因子 1 (SRC-1) 增强人雌激素受体 α 介导的基因表达。
DOI：
10.1016/s0960-0760(03)00257-7
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
Bitter,GrantA
中科院分区：
文献类型：
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作者：
Ellison,AaronR;Lofing,Joan;Bitter,GrantA
以酿酒酵母为材料，构建了人雌激素受体α(ERα)介导的转录激活系统。报告基因的激活水平取决于雌激素反应元件(ERE)相对于翻译起始点的位置和杂交启动子中ERE的数量。ERα多肽G400V氨基酸的改变降低了对17β-雌二醇(E2)的敏感性，表明ERα在酵母和哺乳动物细胞中的激素响应在质量和数量上是相似的。在哺乳动物细胞中共表达ERα功能的有效刺激物sRC-1a，可使ERα介导的基因表达增强5倍以上，且依赖于E2。SRC-1a C末端56个氨基酸的缺失导致了一种增强ERα介导的基因表达能力的蛋白质，它模仿了人SRC-1a相同截断的活性，以及SRC-1e亚型的56个C末端残基被不同的14个氨基酸取代的异构体。选择性雌激素受体调节剂他莫昔芬是ERα介导的基因表达的弱激动剂，这种微弱的活性被sRC-1增强。在SRC-1存在或不存在的情况下，他莫昔芬对E2诱导的基因激活没有影响。与以前报道的基于酵母的ERα反式激活系统不同，在这里报道的系统中，SRC-1作为真正的辅助激活因子发挥作用，应该允许更彻底地剖析参与ERα介导的转录激活的因素。
The yeast Saccharomyces cerevisiae was used to reconstruct a human estrogen receptor α (ERα)-mediated transcription activation system. The level of reporter gene activation was dependent on both the position of the estrogen response element (ERE) relative to the translation start site and the number of EREs in the hybrid promoter. A G400V amino acid alteration in the ERα polypeptide decreased sensitivity to 17β-estradiol (E2), demonstrating the hormone responsiveness of ERα to be qualitatively and quantitatively similar in yeast and mammalian cells. Coexpression of SRC-1a, a potent stimulator of ERα function in mammalian cells, potentiated ERα-mediated gene expression over fivefold in a E2-dependent manner. Deletion of 56 amino acids at the C-terminal end of SRC-1a resulted in a protein with enhanced ability to potentiate ERα-mediated gene expression, which mimics the activity of the same truncation in human SRC-1a as well as the SRC-1e isoform that has the 56 C-terminal residues replaced with a different 14 amino acid peptide. The selective estrogen receptor modulator tamoxifen acted as a weak agonist of ERα-mediated gene expression and this weak activity was potentiated by SRC-1. Tamoxifen had no effect on E2-induced gene activation in either the presence or absence of SRC-1. In contrast to previously reported yeast-based ERα-transactivation systems, the system reported here in which SRC-1 functions as a bona fide coactivator should permit a more thorough dissection of the factors involved in ERα-mediated transcriptional activation.