Essential roles for cohesin in kinetochore and spindle function in Xenopus egg extracts
Essential roles for cohesin in kinetochore and spindle function in Xenopus egg extracts
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DOI：
10.1242/jcs.03277
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发表时间：
2006-12-15
影响因子：
4
通讯作者：
Heald, Rebecca
中科院分区：
文献类型：
--
作者：
Kenney, Renee Deehan;Heald, Rebecca
为了促进它们在有丝分裂纺锤体中的准确分布，姐妹染色单体在DNA复制过程中被拴在一起，通过它们的动粒附着在纺锤体上，并在纺锤体上双向定向，然后在中期到后期的过渡期同时释放，允许它们分离到相反的纺锤体两极。高度保守的粘着蛋白复合体是这一过程的基础，但它在有丝分裂中的作用还没有完全了解。我们发现，从爪蟾卵提取物中的凝聚素耗尽损害姐妹染色单体凝聚力和着丝粒微管相互作用，导致有缺陷的纺锤体附件和染色体排列在中期和后期的错误分离。在缺乏粘着蛋白的情况下，染色体乘客蛋白INCENP和极光B的姐妹动粒配对和着丝粒定位在双极纺锤体附着时丢失。然而，如果通过抑制驱动蛋白-5马达（Eg 5）来防止双极纺锤体的形成，则动粒仍然与正常乘客定位配对。这些观察结果表明，cohesin是不需要建立姐妹协会，但有必要在双极纺锤体部队的存在下保持凝聚力。共耗尽的凝聚素与另一个主要的SMC复合物，凝聚素，显示累积效应的纺锤体组装和染色体结构。这些数据强调了姐妹染色单体凝聚力，动粒和纺锤体功能对凝聚素的基本要求。
To facilitate their accurate distribution by the mitotic spindle, sister chromatids are tethered during DNA replication, attached by their kinetochores and bi-oriented on the spindle, and then simultaneously released at the metaphase to anaphase transition, allowing for their segregation to opposite spindle poles. The highly conserved cohesin complex is fundamental to this process, yet its role in mitosis is not fully understood. We show that depletion of cohesin from Xenopus egg extracts impairs sister chromatid cohesion and kinetochore-microtubule interactions, causing defective spindle attachments and chromosome alignment during metaphase and mis-segregation during anaphase. In the absence of cohesin, sister kinetochore pairing and centromeric localization of chromosomal passenger proteins INCENP and aurora B were lost upon bipolar spindle attachment. However, kinetochores remained paired with normal passenger localization if bipolar spindle formation was prevented by inhibiting the kinesin-5 motor (Eg5). These observations indicate that cohesin is not required to establish sister association, but is necessary to maintain cohesion in the presence of bipolar spindle forces. Co-depletion of cohesin together with another major SMC complex, condensin, revealed cumulative effects on spindle assembly and chromosome architecture. These data underscore the essential requirement for cohesin in sister chromatid cohesion, kinetochore and spindle function.