A Rae1-containing ribonucleoprotein complex is required for mitotic spindle assembly
A Rae1-containing ribonucleoprotein complex is required for mitotic spindle assembly
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DOI：
10.1016/j.cell.2005.02.016
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发表时间：
2005-04-22
期刊：
影响因子：
64.5
通讯作者：
Weis, K
中科院分区：
文献类型：
--
作者：
Blower, MD;Nachury, M;Weis, K
已显示染色体周围的中心体非依赖性微管聚合需要RanGTP的局部梯度，其从核输入受体importin β释放有丝分裂货物。在这里，我们已经使用了基于活性的测定在非洲爪蟾卵提取物纯化的mRNA输出蛋白Rae 1作为由该途径调节的纺锤体组装因子。Rae 1是一种微管相关蛋白，直接与importin β结合。提取物或细胞中Rae 1的缺失严重抑制有丝分裂纺锤体组装。纯化的Rae 1复合物以RanGTP/importin β调节的方式稳定卵提取物中的微管。有趣的是，Rae 1存在于一个大的核糖核蛋白复合物中，它需要RNA才能在体外控制微管动力学。此外，我们提供的证据表明，RNA协会与有丝分裂纺锤体，它发挥了直接的，不依赖于分裂纺锤体组装的作用。我们的研究揭示了RNA在纺锤体形态发生中意想不到的功能。
Centrosome-independent microtubule polymerization around chromosomes has been shown to require a local gradient of RanGTP, which discharges mitotic cargoes from the nuclear import receptor importin beta. Here, we have used an activity-based assay in Xenopus egg extracts to purify the mRNA export protein Rae1 as a spindle assembly factor regulated by this pathway. Rae1 is a microtubule-associated protein that binds directly to importin beta. Depletion of Rae1 from extracts or cells severely inhibits mitotic spindle assembly. A purified Rae1 complex stabilizes microtubules in egg extracts in a RanGTP/importin beta-regulated manner. Interestingly, Rae1 exists in a large ribonucleoprotein complex, which requires RNA for its activity to control microtubule dynamics in vitro. Furthermore, we provide evidence that RNA associates with the mitotic spindle and that it plays a direct, translation-independent role in spindle assembly. Our studies reveal an unexpected function for RNA in spindle morphogenesis.