Depletion of centromeric MCAK leads to chromosome congression and segregation defects due to improper kinetochore attachments
Depletion of centromeric MCAK leads to chromosome congression and segregation defects due to improper kinetochore attachments
复制标题
DOI：
10.1091/mbc.e03-08-0581
复制
发表时间：
2004-03-01
影响因子：
3.3
通讯作者：
Walczak, CE
中科院分区：
文献类型：
--
作者：
Kline-Smith, SL;Khodjakov, A;Walczak, CE
有丝分裂过程中染色体的复杂行为是由着丝粒微管的精确结合和高度调控的聚合动力学完成的。以前的研究表明，Kin is是一种独特的运动蛋白，可以解聚微管，调节染色体的定位。我们鉴定了着丝粒结合的MCAK的免疫荧光定位，发现MCAK在早期定位于内部着丝粒，但中期以着丝粒为主。有趣的是，MCAK在会议期间积累在主要动点，而在分离期间则不积累。我们通过将着丝粒显性负蛋白注射到早期细胞中来测试MCAK中断的后果。着丝粒MCAK的缺失导致着丝粒伸展延迟、染色体聚集减少、排列缺陷和严重的染色体错误分离。染色体移动率没有变化，表明MCAK的主要作用不是移动染色体。此外，我们发现MCAK的破坏会导致多个动粒-微管连接缺陷，包括分节连接、联体连接和联合分体-联体连接。这些发现揭示了Kin在预防和/或纠正不正确的动粒-微管连接方面的重要作用。
The complex behavior of chromosomes during mitosis is accomplished by precise binding and highly regulated polymerization dynamics of kinetochore microtubules. Previous studies have implicated Kin Is, unique kinesins that depolymerize microtubules, in regulating chromosome positioning. We have characterized the immunofluorescence localization of centromere-bound MCAK and found that MCAK localized to inner kinetochores during prophase but was predominantly centromeric by metaphase. Interestingly, MCAK accumulated at leading kinetochores during congression but not during segregation. We tested the consequences of MCAK disruption by injecting a centromere dominant-negative protein into prophase cells. Depletion of centromeric MCAK led to reduced centromere stretch delayed chromosome congression, alignment defects, and severe missegregation of chromosomes. Rates of chromosome movement were unchanged, suggesting that the primary role of MCAK is not to move chromosomes. Furthermore, we found that disruption of MCAK leads to multiple kinetochore-microtubule attachment defects, including merotelic, syntelic, and combined merotelic-syntelic attachments. These findings reveal an essential role for Kin Is in prevention and/or correction of improper kinetochore-microtubule attachments.