Cohesion fatigue

What is cohesion fatigue? Cohesion fatigue is the asynchronous separation of chromatids in cells that are arrested or delayed at metaphase. In normal anaphase, synchronous chromatid separation is followed by cytokinesis and mitotic exit. In contrast, after cohesion fatigue, cells usually remain locked in mitosis for some time after chromatids separate. Cohesion fatigue requires the mechanical forces generated by the sister kinetochores pulling in opposite directions on the mitotic spindle microtubules, and any naturally occurring or experimentally induced metaphase delay will lead to cohesion fatigue as long as spindle function is preserved. Cohesion fatigue is not observed in cells arrested in mitosis with microtubule poisons because the outward pulling forces are lost. The beginnings of cohesion fatigue can be detected after only 1–2 hours of metaphase, but complete chromatid separation usually takes longer. Cohesion fatigue initiates with separation of the centromeric regions of the chromosome and then spreads outward along the chromosome arms.