Human Wapl Is a Cohesin-Binding Protein that Promotes Sister-Chromatid Resolution in Mitotic Prophase

摘要: Summary 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 chromosome arms when cell enters mitotic prophase, leading formation metaphase with two cytologically discernible chromatids. This process known as sister-chromatid resolution. Although kinases have been implicated in this process, it remains unknown exactly how cohesin-mediated destabilized at mechanistic level. Results wings apart-like (Wapl) protein was originally identified gene product that potentially regulates heterochromatin organization in Drosophila melanogaster . We show human ortholog Wapl is a cohesin-binding facilitates cohesin's timely release prophase. Depletion HeLa cells causes transient accumulation prometaphase-like display poorly resolved sister chromatids high level cohesin. Reduction relieves Wapl-depletion phenotype, and depletion rescues premature separation observed in Sgo1-depleted or Esco2-depleted cells. Conversely, overexpression separation of physically associates HeLa-cell nuclear extracts. Remarkably, vitro reconstitution experiments demonstrate forms a stoichiometric, ternary regulatory subunits implicating its noncatalytic function inactivating ability interact chromatin. Conclusions new regulator chromatid resolution promotes directly interacting subunits.