Andalusian Center for Developmental Biology (CABD); Consejo Superior de Investigaciones Científicas, Universidad Pablo de Olavide and Junta de Andalucía, 41013 Seville, Spain.
Instituto de Biología Funcional y Genómica (IBFG); Consejo Superior de Investigaciones Científicas and Universidad de Salamanca, 37007 Salamanca, Spain.
Mol Biol Cell. 2022 May 1;33(5):br8. doi: 10.1091/mbc.E20-09-0600. Epub 2022 Mar 11.
During cell cycle progression in metazoans, the kinetochore is assembled at mitotic onset and disassembled during mitotic exit. Once assembled, the kinetochore complex attached to centromeres interacts directly with the spindle microtubules, the vehicle of chromosome segregation. This reassembly program is assumed to be absent in budding and fission yeast, because most kinetochore proteins are stably maintained at the centromeres throughout the entire cell cycle. Here, we show that the reassembly program of the outer kinetochore at mitotic onset is unexpectedly conserved in the fission yeast . We identified this behavior by removing the Rabl chromosome configuration, in which centromeres are permanently associated with the nuclear envelope beneath the spindle pole body during interphase. In addition to having evolutionary implications for kinetochore reassembly, our results aid the understanding of the molecular processes responsible for kinetochore disassembly and assembly during mitotic entry.
在真核生物的细胞周期进展过程中，动粒在有丝分裂开始时组装，并在有丝分裂末期解体。一旦组装完成，与着丝粒直接相互作用的纺锤体微管就会附着在动粒复合物上，这是染色体分离的载体。这个重新组装程序在芽殖酵母和裂殖酵母中被认为是不存在的，因为大多数动粒蛋白在整个细胞周期中都稳定地维持在着丝粒上。在这里，我们发现在有丝分裂开始时，外动粒的重新组装程序在裂殖酵母中出人意料地保守。我们通过去除 Rabl 染色体构型来识别这种行为，在该构型中，着丝粒在有丝分裂间期永久与纺锤体极体下方的核膜相连。除了对动粒重新组装具有进化意义外，我们的结果还有助于理解负责有丝分裂进入时动粒解体和组装的分子过程。
