Reductional meiosis I chromosome segregation is established by coordination of key meiotic kinases

Meiosis produces gametes through a specialised, two-step cell division, which is highly error-prone in humans. Reductional meiosis I, where maternal and paternal chromosomes (homologs) segregate, is followed by equational meiosis II, where sister chromatids separate. Uniquely during meiosis I, sister kinetochores are monooriented and pericentromeric cohesin is protected. Here, we demonstrate that these key adaptations for reductional chromosome segregation are achieved through separable control of multiple kinases by the meiosis I-specific budding yeast Spo13 protein. Recruitment of Polo kinase to kinetochores directs monoorientation, while, independently, cohesin protection is achieved by controlling the effects of cohesin kinases. Therefore, reductional chromosome segregation, the defining feature of meiosis, is established by multifaceted kinase control by a master regulator. The recent identification of Spo13 orthologs, fission yeast Moa1 and mouse MEIKIN, suggests that kinase coordination by a master meiosis I regulator may be a general feature in the establishment of reductional chromosome segregation.

减数分裂（Meiosis）通过特化的两步式细胞分裂产生配子，该过程在人类中极易出现差错。介导母源与父源染色体（即同源染色体，homologs）分离的还原分裂型减数分裂I期，紧随其后的是使姐妹染色单体分离的等式分裂型减数分裂II期。唯有在减数分裂I期中，姐妹动粒（sister kinetochores）呈单定向状态，且着丝粒周边黏连蛋白（cohesin）受到保护。本研究证实，这类为实现还原型染色体分离所必需的关键适应性特征，是通过减数分裂I期特异性出芽酵母Spo13蛋白对多种激酶的可分离式调控实现的。将Polo激酶（Polo kinase）招募至动粒可介导单定向状态，而独立于此的黏连蛋白保护则通过调控黏连蛋白激酶（cohesin kinases）的作用效应达成。由此可见，作为减数分裂标志性特征的还原型染色体分离，是由一类主调控因子通过多维度的激酶调控所确立的。近期鉴定出的Spo13同源物（orthologs）——裂殖酵母Moa1与小鼠MEIKIN——提示，由主减数分裂I期调控因子协调激酶活性，或许是还原型染色体分离建立过程中的普遍机制。