The kinesinlike protein Subito contributes to central spindle assembly and organization of the meiotic spindle in Drosophila oocytes
The kinesinlike protein Subito contributes to central spindle assembly and organization of the meiotic spindle in Drosophila oocytes
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DOI：
10.1091/mbc.e04-11-0964
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发表时间：
2005-10-01
影响因子：
3.3
通讯作者：
McKim, KS
中科院分区：
文献类型：
--
作者：
Jang, JK;Rahman, T;McKim, KS
在许多物种的卵母细胞中，在没有中心体的情况下形成双极纺锤体。果蝇卵母细胞染色体在微管成核中起重要作用，微管成核先于微管成束和组装成双极纺锤体。在这里，我们提出的证据表明，一个地区类似的后期中央纺锤体的功能，以组织无中心体纺锤体。亚位突变体的特征是在减数分裂Ⅰ时形成三极或单极纺锤体，同源染色体不分离。Subito编码一种类似驱动蛋白的蛋白质，与减数分裂中心纺锤体相关，与其在驱动蛋白6/MKLP 1家族中的分类一致。已知这类蛋白质是胞质分裂所需的，但我们的研究结果表明了纺锤体形成的新功能。减数分裂的中央纺锤体出现在前中期，包括乘客复合蛋白，如AurB和Incexp。与有丝分裂细胞不同，过客蛋白在分裂后期之前不与着丝粒结合。在Subito的情况下，中央纺锤体的形成是有缺陷的，AurB和Incexp未能正确定位。我们建议，Subito是建立和/或维持果蝇卵母细胞的中央纺锤体所必需的，这替代了中心体在组织双极纺锤体中的作用。
In the oocytes of many species, bipolar spindles form in the absence of centrosomes. Drosophila melanogaster oocyte chromosomes have a major role in nucleating microtubules, which precedes the bundling and assembly of these microtubules into a bipolar spindle. Here we present evidence that a region similar to the anaphase central spindle functions to organize acentrosomal spindles. Subito mutants are characterized by the formation of tripolar or monopolar spindles and nondisjunction of homologous chromosomes at meiosis I. Subito encodes a kinesinlike protein and associates with the meiotic central spindle, consistent with its classification in the Kinesin 6/MKLP1 family. This class of proteins is known to be required for cytokinesis, but our results suggest a new function in spindle formation. The meiotic central spindle appears during prometaphase and includes passenger complex proteins such as AurB and Incenp. Unlike mitotic cells, the passenger proteins do not associate with centromeres before anaphase. In the absence of Subito, central spindle formation is defective and AurB and Incenp fail to properly localize. We propose that Subito is required for establishing and/or maintaining the central spindle in Drosophila oocytes, and this substitutes for the role of centrosomes in organizing the bipolar spindle.