In animal cells, faithful chromosome segregation depends on the assembly of a bipolar spindle driven by the timely separation of the two centrosomes. Here we took advantage of the highly stereotypical cell divisions in Caenorhabditis elegans embryos to identify new regulators of centrosome separation. We find that at the two-cell stage, the somatic AB cell initiates centrosome separation later than the germline P1 cell. This difference is strongly exacerbated by the depletion of the kinesin-13 KLP-7/MCAK, resulting in incomplete centrosome separation at NEBD in AB but not P1. Our genetic and cell biology data indicate that this phenotype depends on cell polarity via the enrichment in AB of the mitotic kinase PLK-1, which itself limits the cortical localization of the dynein-binding NuMA orthologue LIN-5. We postulate that the timely separation of centrosomes is regulated in a cell type–dependent manner.

中文翻译：

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线虫胚胎中细胞极性依赖性中心体分离

在动物细胞中，忠实的染色体分离取决于两个中心体及时分离驱动的双极纺锤体的组装。在这里，我们利用秀丽隐杆线虫胚胎中高度刻板的细胞分裂来识别中心体分离的新调节因子。我们发现，在双细胞阶段，体细胞 AB 细胞比种系 P1 细胞晚启动中心体分离。这种差异因驱动蛋白 13 KLP-7/MCAK 的耗尽而严重加剧，导致 AB 中 NEBD 处的中心体分离不完全，但 P1 中则不然。我们的遗传和细胞生物学数据表明，这种表型取决于细胞极性，通过有丝分裂激酶 PLK-1 的 AB 富集，这本身限制了动力蛋白结合 NuMA 直向同源物 LIN-5 的皮质定位。我们假设中心体的及时分离以细胞类型依赖性方式受到调节。