Waksman Institute and Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, NJ.
J Cell Biol. 2021 Jun 7;220(6). doi: 10.1083/jcb.202006018.
The chromosomes in the oocytes of many animals appear to promote bipolar spindle assembly. In Drosophila oocytes, spindle assembly requires the chromosome passenger complex (CPC), which consists of INCENP, Borealin, Survivin, and Aurora B. To determine what recruits the CPC to the chromosomes and its role in spindle assembly, we developed a strategy to manipulate the function and localization of INCENP, which is critical for recruiting the Aurora B kinase. We found that an interaction between Borealin and the chromatin is crucial for the recruitment of the CPC to the chromosomes and is sufficient to build kinetochores and recruit spindle microtubules. HP1 colocalizes with the CPC on the chromosomes and together they move to the spindle microtubules. We propose that the Borealin interaction with HP1 promotes the movement of the CPC from the chromosomes to the microtubules. In addition, within the central spindle, rather than at the centromeres, the CPC and HP1 are required for homologous chromosome bi-orientation.
许多动物卵母细胞中的染色体似乎能促进两极纺锤体的组装。在果蝇卵母细胞中，纺锤体的组装需要染色体乘客复合物（CPC），它由 INCENP、Borealin、Survivin 和 Aurora B 组成。为了确定是什么将 CPC 招募到染色体上，以及它在纺锤体组装中的作用，我们开发了一种操纵 INCENP 功能和定位的策略，INCENP 对于招募 Aurora B 激酶至关重要。我们发现，Borealin 与染色质之间的相互作用对于 CPC 被招募到染色体上至关重要，并且足以构建动粒并招募纺锤体微管。HP1 与 CPC 在染色体上共定位，并一起移动到纺锤体微管上。我们提出，Borealin 与 HP1 的相互作用促进了 CPC 从染色体到微管的运动。此外，在中央纺锤体中，而不是在着丝粒处，CPC 和 HP1 对于同源染色体的双定向是必需的。
