Das Arunika, Shah Shital J, Fan Bensen, Paik Daniel, DiSanto Daniel J, Hinman Anna Maria, Cesario Jeffry M, Battaglia Rachel A, Demos Nicole, McKim Kim S
Waksman Institute, Rutgers, The State University of New Jersey, New Jersey 08854.
Waksman Institute, Rutgers, The State University of New Jersey, New Jersey 08854 Department of Genetics, Rutgers, The State University of New Jersey, New Jersey 08854
Genetics. 2016 Jan;202(1):61-75. doi: 10.1534/genetics.115.181081. Epub 2015 Nov 12.
Oocytes segregate chromosomes in the absence of centrosomes. In this situation, the chromosomes direct spindle assembly. It is still unclear in this system which factors are required for homologous chromosome bi-orientation and spindle assembly. The Drosophila kinesin-6 protein Subito, although nonessential for mitotic spindle assembly, is required to organize a bipolar meiotic spindle and chromosome bi-orientation in oocytes. Along with the chromosomal passenger complex (CPC), Subito is an important part of the metaphase I central spindle. In this study we have conducted genetic screens to identify genes that interact with subito or the CPC component Incenp. In addition, the meiotic mutant phenotype for some of the genes identified in these screens were characterized. We show, in part through the use of a heat-shock-inducible system, that the Centralspindlin component RacGAP50C and downstream regulators of cytokinesis Rho1, Sticky, and RhoGEF2 are required for homologous chromosome bi-orientation in metaphase I oocytes. This suggests a novel function for proteins normally involved in mitotic cell division in the regulation of microtubule-chromosome interactions. We also show that the kinetochore protein, Polo kinase, is required for maintaining chromosome alignment and spindle organization in metaphase I oocytes. In combination our results support a model where the meiotic central spindle and associated proteins are essential for acentrosomal chromosome segregation.
卵母细胞在没有中心体的情况下分离染色体。在这种情况下，染色体指导纺锤体组装。在这个系统中，同源染色体双定向和纺锤体组装需要哪些因素仍不清楚。果蝇驱动蛋白6蛋白Subito虽然对有丝分裂纺锤体组装不是必需的，但在卵母细胞中是组织双极减数分裂纺锤体和染色体双定向所必需的。与染色体乘客复合体（CPC）一起，Subito是减数第一次分裂中期中央纺锤体的重要组成部分。在本研究中，我们进行了遗传筛选以鉴定与subito或CPC组分Incenp相互作用的基因。此外，还对在这些筛选中鉴定出的一些基因的减数分裂突变体表型进行了表征。我们部分通过使用热休克诱导系统表明，中央纺锤体蛋白组分RacGAP50C以及胞质分裂的下游调节因子Rho1、Sticky和RhoGEF2是减数第一次分裂中期卵母细胞中同源染色体双定向所必需的。这表明通常参与有丝分裂细胞分裂的蛋白质在微管 - 染色体相互作用调节中具有新功能。我们还表明，动粒蛋白Polo激酶是维持减数第一次分裂中期卵母细胞中染色体排列和纺锤体组织所必需的。综合我们的结果支持了一个模型，即减数分裂中央纺锤体和相关蛋白对于无中心体染色体分离至关重要。
