Multiple determinants and consequences of cohesion fatigue in mammalian cells

Abstract

Cells delayed in metaphase with intact mitotic spindles undergo cohesion fatigue, where sister chromatids separate asynchronously, while cells remain in mitosis. Cohesion fatigue requires release of sister chromatid cohesion. However, the pathways that breach sister chromatid cohesion during cohesion fatigue remain unknown. Using moderate-salt buffers to remove loosely bound chromatin cohesin, we show that “cohesive” cohesin is not released during chromatid separation during cohesion fatigue. Using a regulated protein heterodimerization system to lock different cohesin ring interfaces at specific times in mitosis, we show that the Wapl-mediated pathway of cohesin release is not required for cohesion fatigue. By manipulating microtubule stability and cohesin complex integrity in cell lines with varying sensitivity to cohesion fatigue, we show that rates of cohesion fatigue reflect a dynamic balance between spindle pulling forces and resistance to separation by interchromatid cohesion. Finally, while massive separation of chromatids in cohesion fatigue likely produces inviable cell progeny, we find that short metaphase delays, leading to partial chromatid separation, predispose cells to chromosome missegregation. Thus, complete separation of one or a few chromosomes and/or partial separation of sister chromatids may be an unrecognized but common source of chromosome instability that perpetuates the evolution of malignant cells in cancer.

Replication stress induces mitotic death through parallel pathways regulated by WAPL and telomere deprotection

“…4b). These observations are consistent with "cohesion fatigue", a phenomena where sustained microtubule pulling forces exerted during mitotic arrest drive unscheduled chromosome segregation prior to anaphase onset 20,21 . We interpret these data to indicate the moderate and severe conditions represent a phenotypic continuum of cohesion fatigue as sister chromatids are progressively separated during mitotic arrest.…”

Non-random Mis-segregation of Human Chromosomes

“…Cohesion fatigue could elevate chromosome mis-segregation because of effects on centromeric geometry or flexibility that might increase merotelic attachment rate ( Sakuno et al., 2009 ). It has also been suggested that stretched inter-kinetochore distance seen in mild cohesion fatigue (i.e., before complete PSCS) could displace high inner centromeric aurora B, leading to increased incidence of merotelic attachment ( Sapkota et al., 2017 ). Alternatively, because multiple studies have demonstrated an intricate interplay between chromosome cohesion factors and regulation of the chromosomal passenger complex (CPC), responsible for error correction (reviewed in Trivedi and Stukenberg, 2016 , Mirkovic and Oliveira, 2017 , Kleyman et al., 2014 ), it is possible that cohesion fatigue might prevent efficient correction of mal-attachments by improper regulation of the CPC.…”

Aurora B kinase activity–dependent and –independent functions of the chromosomal passenger complex in regulating sister chromatid cohesion

“…We demonstrated that Wapl depletion restores proper strength of centromeric cohesion in the absence of INCENP-HP1 interaction. In contrast, a recent study showed that Wapl-mediated opening of cohesin rings is not required after metaphase arrest to separate sister chromatid in cohesion fatigue (89). Thus, it seems that the sister chromatid cohesion defects in cells lacking INCENP-HP1 interaction are not simply an accelerated cohesion fatigue defect.…”