The Prereplication Complex Recruits XEco2 to Chromatin to Promote Cohesin Acetylation in Xenopus Egg Extracts
The Prereplication Complex Recruits XEco2 to Chromatin to Promote Cohesin Acetylation in Xenopus Egg Extracts
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DOI：
10.1016/j.cub.2012.04.013
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发表时间：
2012-06-05
期刊：
影响因子：
9.2
通讯作者：
Takahashi, Tatsuro S.
中科院分区：
文献类型：
--
作者：
Higashi, Torahiko L.;Ikeda, Megumi;Takahashi, Tatsuro S.
背景：姐妹染色单体是由环状的黏连蛋白复合体连接在一起的，黏连蛋白复合体在DNA复制前被装载到染色体上。姐妹染色体之间的凝聚力是在DNA复制过程中建立的，它需要通过进化上保守的凝聚素乙酰转移酶（CoAT）对凝聚素的Smc 3亚基进行乙酰化。然而，CoAT如何被招募到染色质以及粘着蛋白乙酰化如何受到调节仍不清楚。结果：我们发现粘着蛋白乙酰化需要前RC依赖性染色质加载粘着蛋白，但令人惊讶的是，它不依赖于异脓卵提取物中的DNA合成。免疫耗竭实验表明，XEco 2是CoAT负责Smc 3乙酰化和姐妹染色单体凝聚力。招募XEco 2染色质上是依赖于前RC组装，但独立的粘附素加载和DNA合成。两个短的N-末端基序，PBM-A和PBM-B，这是保守的脊椎动物Esco 2/XEco 2同源物，共同的前RC依赖的染色质协会XEco 2，粘连蛋白乙酰化，和随后的姐妹染色单体凝聚力是必不可少的。XEco 2中保守的PCNA相互作用蛋白盒在很大程度上是Smc 3乙酰化的抑制剂，但部分是凝聚力所需的。乙酰化的粘附素与DNA的相互作用是稳定的，对盐洗涤处理后的DNA replication.Conclusions：我们的研究结果表明，前RC形成调节染色质协会XEco 2在非洲爪蟾卵提取物。我们建议，这个反应是至关重要的乙酰化粘连蛋白，其DNA结合随后通过DNA复制稳定。
Background: Sister chromatids are held together by the ring-shaped cohesin complex, which is loaded onto chromosomes before DNA replication. Cohesion between sister chromosomes is established during DNA replication, and it requires acetylation of the Smc3 subunit of cohesin by evolutionally conserved cohesin acetyltransferases (CoATs). However, how CoATs are recruited to chromatin and how cohesin acetylation is regulated remain unclear.Results: We found that cohesin acetylation requires pre-RC-dependent chromatin loading of cohesin, but surprisingly, it is independent of DNA synthesis in Xeno pus egg extracts. Immunodepletion experiments revealed that XEco2 is the CoAT responsible for Smc3 acetylation and sister chromatid cohesion. Recruitment of XEco2 onto chromatin was dependent on pre-RC assembly but was independent of cohesin loading and DNA synthesis. Two short N-terminal motifs, PBM-A and PBM-B, which are conserved among vertebrate Esco2/XEco2 homologs, were collectively essential for pre-RC-dependent chromatin association of XEco2, cohesin acetylation, and subsequent sister chromatid cohesion. The conserved PCNA-interacting protein box in XEco2 was largely dispensable for Smc3 acetylation but was partially required for cohesion. Interaction of acetylated cohesin with DNA was stabilized against salt-wash treatments after DNA replication.Conclusions: Our results demonstrate that pre-RC formation regulates chromatin association of XEco2 in Xenopus egg extracts. We propose that this reaction is critical to acetylate cohesin, whose DNA binding is subsequently stabilized by DNA replication.