PDF(Pubmed)
Abstract：
The reductional division of meiosis I requires the separation of chromosome pairs towards opposite poles. We have previously implicated the outer kinetochore protein SPC105R/KNL1 in driving meiosis I chromosome segregation through lateral attachments to microtubules and coorientation of sister centromeres. To identify the domains of SPC105R that are critical for meiotic chromosome segregation, an RNAi-resistant gene expression system was developed. We found that the SPC105R C-terminal domain (aa 1284-1960) is necessary and sufficient for recruiting NDC80 to the kinetochore and building the outer kinetochore. Furthermore, the C-terminal domain recruits BUBR1, which in turn recruits the cohesion protection proteins MEI-S332 and PP2A. Of the remaining 1283 amino acids, we found the first 473 are most important for meiosis. The first 123 amino acids of the N-terminal half of SPC105R contain the conserved SLRK and RISF motifs that are targets of PP1 and Aurora B kinase and are most important for regulating the stability of microtubule attachments and maintaining metaphase I arrest. The region between amino acids 124 and 473 are required for lateral microtubule attachments and biorientation of homologues, which are critical for accurate chromosome segregation in meiosis I.
摘要：
减数分裂I的减数分裂需要将染色体对朝着相反的两极分离。我们以前曾暗示外动粒蛋白SPC105R/KNL1通过侧向附着到微管和姐妹着丝粒的共同取向来驱动减数分裂I染色体分离。为了鉴定对减数分裂染色体分离至关重要的SPC105R结构域，开发了RNAi抗性基因表达系统。我们发现，SPC105RC末端域（aa1284-1960）对于将NDC80招募到动粒并构建外部动粒是必要且足够的。此外，C端结构域招募BUBR1，进而招募内聚保护蛋白MEI-S332和PP2A。剩下的1283个氨基酸,我们发现前473对减数分裂最重要。SPC105RN末端一半的前123个氨基酸包含保守的SLRK和RSF基序，它们是PP1和AuroraB激酶的靶标，对于调节微管附着的稳定性和维持中期I阻滞最重要。氨基酸124和473之间的区域是侧向微管附着和同源物的双向所必需的，这对于减数分裂中准确的染色体分离至关重要I.
