Human Wapl is a cohesin-binding protein that promotes sister-chromatid resolution in mitotic prophase
Human Wapl is a cohesin-binding protein that promotes sister-chromatid resolution in mitotic prophase
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DOI：
10.1016/j.cub.2006.10.061
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发表时间：
2006-12-19
期刊：
影响因子：
9.2
通讯作者：
Hirano, Tatsuya
中科院分区：
文献类型：
--
作者：
Gandhi, Rita;Gillespie, Peter J.;Hirano, Tatsuya
工作背景：重复染色体（姐妹染色单体）之间的连锁是在S期通过粘蛋白（一种从酵母到人类都保守的多亚基复合物）的作用建立的。当细胞进入有丝分裂前期时，大多数粘着蛋白从染色体臂上解离，导致形成具有两个细胞学可识别染色单体的中期染色体。这个过程被称为姐妹染色单体分辨。虽然有两个有丝分裂激酶已经牵连在这个过程中，它仍然未知到底是如何的粘连蛋白介导的连接是不稳定的，在一个mechanistic level.Results：翅膀分离样（Wapl）蛋白最初被确定为一个基因产物，可能调节异染色质组织在果蝇。我们表明，人类直系同源的Wapl是一种粘着蛋白结合蛋白，促进粘着蛋白的及时释放，从染色体臂在前期。从HeLa细胞中消耗Wapl会导致具有染色体的前中期样细胞的短暂积累，所述染色体显示具有高水平粘附素的分辨不佳的姐妹染色单体。减少粘附素缓解Wapl耗竭表型，Wapl耗竭挽救在Sgo 1耗竭或Eco 2耗竭细胞中观察到的过早姐妹分离。相反，Wapl的过表达会导致姐妹染色单体过早分离。Wapl与HeLa细胞核提取物中的粘着蛋白物理缔合。值得注意的是，在体外重建实验表明，Wapl形成一个化学计量，三元复合物的两个调节亚基的凝聚素，暗示其非催化功能在灭活凝聚素的能力，相互作用与chromatin.Conclusions：Wapl是一个新的调节剂的姐妹染色单体的分辨率和促进释放的凝聚素从染色体直接与其调节亚基。
Background: The linkage between duplicated chromosomes (sister chromatids) is established during S phase by the action of cohesin, a multisubunit complex conserved from yeast to humans. Most cohesin dissociates from chromosome arms when the cell enters mitotic prophase, leading to the formation of metaphase chromosomes with two cytologically discernible chromatids. This process is known as sister-chromatid resolution. Although two mitotic kinases have been implicated in this process, it remains unknown exactly how the cohesin-mediated linkage is destabilized at a mechanistic level.Results: The wings apart-like (Wapl) protein was originally identified as a gene product that potentially regulates heterochromatin organization in Drosophila melanogaster. We show that the human ortholog of Wapl is a cohesin-binding protein that facilitates cohesin's timely release from chromosome arms during prophase. Depletion of Wapl from HeLa cells causes transient accumulation of prometaphase-like cells with chromosomes that display poorly resolved sister chromatids with a high level of cohesin. Reduction of cohesin relieves the Wapl-depletion phenotype, and depletion of Wapl rescues premature sister separation observed in Sgo1-depleted or Esco2-depleted cells. Conversely, overexpression of Wapl causes premature separation of sister chromatids. Wapl physically associates with cohesin in HeLa-cell nuclear extracts. Remarkably, in vitro reconstitution experiments demonstrate that Wapl forms a stoichiometric, ternary complex with two regulatory subunits of cohesin, implicating its noncatalytic function in inactivating cohesin's ability to interact with chromatin.Conclusions: Wapl is a new regulator of sister chromatid resolution and promotes release of cohesin from chromosomes by directly interacting with its regulatory subunits.