The chromatin remodeling protein, SRCAP, is critical for deposition of the histone variant H2A.Z at promoters
The chromatin remodeling protein, SRCAP, is critical for deposition of the histone variant H2A.Z at promoters
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DOI：
10.1074/jbc.m703418200
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发表时间：
2007-09-07
影响因子：
4.8
通讯作者：
Chrivia, John C.
中科院分区：
文献类型：
--
作者：
Wong, Madeline M.;Cox, Linda K.;Chrivia, John C.
在酿酒酵母中的研究表明组蛋白变体H2 A。Z通过染色质重塑蛋白Swr 1沉积在启动子处，并在转录调控中起关键作用。然而，在高等真核生物中，对H2 A的分布、沉积方式和功能知之甚少。Z在促销员。使用生物化学研究，我们以前证明，SRCAP（SNF-2相关CREB结合蛋白激活蛋白），人类直系同源的Swr 1，可以催化沉积的H2 A。Z进入核小体。解决SRCAP是否指向H2 A。Z沉积在体内，通过染色质免疫沉淀（ChIP）-芯片测定鉴定SRCAP靶向的启动子。这些启动子的子集上的ChIP测定证实了SRCAP在失活和活性启动子上的存在。在活性SP-1、G3 BP和FAD合成酶启动子上观察到最高水平的SRCAP。对这些启动子的详细分析表明SRCAP结合位点与H2 A的位点重叠或邻近。Z沉积。使用siRNA敲低SRCAP水平导致这些启动子处的SRCAP丧失，减少H2 A的沉积。Z和乙酰化的H2 A。Z，以及SP-1、G3 BP和FAD合成酶mRNA水平的降低。因此，这些研究提供了第一个证据表明，SRCAP被募集到启动子中，并且对于H2 A的沉积至关重要。
Studies in Saccharomyces cerevisiae indicate the histone variant H2A. Z is deposited at promoters by the chromatin remodeling protein Swr1 and plays a critical role in the regulation of transcription. In higher eukaryotes, however, little is known about the distribution, method of deposition, and function of H2A. Z at promoters. Using biochemical studies, we demonstrated previously that SRCAP ( SNF-2-related CREB-binding protein activator protein), the human ortholog of Swr1, could catalyze deposition of H2A. Z into nucleosomes. To address whether SRCAP directs H2A. Z deposition in vivo, promoters targeted by SRCAP were identified by a chromatin immunoprecipitation ( ChIP)-on-chip assay. ChIP assays on a subset of these promoters confirmed the presence of SRCAP on inactive and active promoters. The highest levels of SRCAP were observed on the active SP-1, G3BP, and FAD synthetase promoters. Detailed analyses of these promoters indicate sites of SRCAP binding overlap or occur adjacent to the sites of H2A. Z deposition. Knockdown of SRCAP levels using siRNA resulted in loss of SRCAP at these promoters, decreased deposition of H2A. Z and acetylated H2A. Z, and a decrease in levels of SP-1, G3BP, and FAD synthetase mRNA. Thus, these studies provide the first evidence that SRCAP is recruited to promoters and is critical for the deposition of H2A.