Regulation of human estrogen receptor alpha-mediated gene transactivation in Saccharomyces cerevisiae by human coactivator and corepressor proteins.
Regulation of human estrogen receptor alpha-mediated gene transactivation in Saccharomyces cerevisiae by human coactivator and corepressor proteins.
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人类共激活剂和辅阻遏蛋白对酿酒酵母中人类雌激素受体α介导的基因反式激活的调节。
DOI：
10.1016/j.jsbmb.2006.11.001
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发表时间：
2007
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：
Bitter,GrantA
使用天然ERα和G400 V变体在酵母酿酒酵母中评估了人雌激素受体α（ERα）介导的转录激活。先前的研究表明，共表达人SRC-1（哺乳动物细胞中ERα功能的有效刺激物）以E2依赖性方式增强ERα介导的酵母基因表达超过5倍。在本研究中，另外两种人辅激活蛋白被证明可以增强ERα介导的酵母基因表达。SRC 2增强反式激活2至3倍，而SRC 3增强反式激活5至8倍。两种人共激活因子均以E2依赖性方式增强天然ERα和G400 V变体。还在酵母中评价了人辅阻遏蛋白的作用。雌激素受体活性抑制剂（REA）不影响ERα（任一亚型）对E2诱导的反式激活作用。然而，在共表达人SRC 1的菌株中，REA将E2诱导的反式激活降低到仅用ERα观察到的水平。此外，SRC 1增强作用的抑制对天然ERα是特异性的，因为REA对G400 V变体的SRC 1增强作用没有影响。此外，REA的抑制作用对SRC 1具有特异性，因为SRC 2和SRC 3对ERα（任一亚型）反式激活的增强作用不受REA共表达的影响。这些结果支持先前在哺乳动物细胞中的观察结果，即REA不阻止ERα与DNA结合，但确实抑制SRC 1增强ERα介导的反式激活。本研究的结果进一步表征了REA介导的阻遏，并证明了该酵母系统用于解剖参与人ERα调节基因反式激活的分子机制的实用性。
Human estrogen receptor α (ERα)-mediated transcription activation was evaluated in the yeast Saccharomyces cerevisiae using both the native ERα and a G400V variant. A previous study demonstrated that coexpression of human SRC-1, a potent stimulator of ERα function in mammalian cells, potentiated ERα-mediated gene expression in yeast over five-fold in an E2-dependent manner. In the present study, two additional human coactivator proteins were shown to potentiate ERα-mediated gene expression in yeast. SRC2 potentiated transactivation two- to three-fold while SRC3 potentiated transactivation five- to eight-fold. Both human coactivators potentiated both the native ERα and the G400V variant in an E2-dependent manner. The effect of a human corepressor protein was also evaluated in yeast. Repressor of estrogen receptor activity (REA) did not affect E2-induced transactivation by ERα (either isoform). However, in a strain that coexpressed human SRC1, REA reduced E2-induced transactivation to that observed with ERα alone. Furthermore, repression of SRC1 potentiation was specific for the native ERα since REA had no effect on SRC1 potentiation of the G400V variant. Additionally, REA repression was specific for SRC1 since potentiation of ERα (either isoform) transactivation by SRC2 and SRC3 was unaffected by coexpression of REA. These results support previous observations in mammalian cells that REA does not prevent ERα from binding to DNA but does inhibit potentiation of ERα-mediated transactivation by SRC1. The results in the present study further characterize REA-mediated repression, and demonstrate the utility of this yeast system for dissecting molecular mechanisms involved in regulating gene transactivation by human ERα.