Mechanism For The Protection Of Centromeric Cohesion By Haspin

Sister-chromatid cohesion,mediated by the multi-subunit cohesin complex,must be precisely regulated to prevent chromosome mis-segregation.In prophase and prometaphase,while the bulk of cohesin on chromosome arms is removed by its antagonist Wapl,cohesin at centromeres is retained to ensure chromosome biorientation until anaphase onset.It remains incompletely understood how centromeric cohesin is protected against Wapl in mitosis.Here we established several Haspin-KO stable cell lines using CRISPR/Cas9-mediated genome editing in HeLa cells.Live cell imaging showes prolonged duration of mitosis in these Haspin-KO cells.And Haspin-KO cells also show weakened centromeric cohesion and increased PCS(premature chromatid separation).Importantly,we demonstrate that the mitotic histone kinase Haspin 'binds to the cohesin regulatory subunit Pds5B through a conserved YGA/R motif in its non-catalytic N-terminus both in cell and in vitro.Haspin-Pds5B interaction can impede Wapl binding to Pds5B.Disrupting endogenous or exogenous Haspin-Pds5B interaction causes weakened centromeric cohesion and premature chromatid separation,which can be reverted by centromeric targeting of a N-terminal short fragment of Haspin containing the Pds5B-binding motif,or by preventing Wapl-dependent cohesin removal.Conversely,excessive Haspin capable of binding Pds5B displaces Wapl from Pds5B and suppresses Wapl activity,and largely bypasses the Wapl antagonist Sgol for cohesion protection.Taken together,the Haspin-Pds5B interaction is required to ensure proper sister-chromatid cohesion,likely through antagonizing Wapl-mediated cohesin release from mitotic centromeres.Mitosis is the basis of biological reproduction,growth and development.This study illustrates the mechanism of Haspin protecting centromeric cohesion,which can help us better understand the molecular mechanism of mitosis.