In prophase of meiosis I, homologous partner chromosomes pair and become connected by crossovers. Chiasmata, the connections formed between the partners enable the chromosome pair, called a bivalent, to attach as a single unit to the spindle. When the meiosis I spindle forms in prometaphase, most bivalents are associated with a single spindle pole and go through a series of oscillations on the spindle, attaching to and detaching from microtubules until the partners of the bivalent are bi-oriented, that is, attached to microtubules from opposite sides of the spindle, and prepared to be segregated at anaphase I. The conserved, kinetochore-associated kinase, Mps1, is essential for the bivalents to be pulled by microtubules across the spindle in prometaphase. Here we show that MPS1 is not required for kinetochores to attach microtubules but instead is necessary to trigger the migration of microtubule-attached kinetochores towards the poles. Our data support the model that Mps1 triggers depolymerization of microtubule ends once they attach to kinetochores in prometaphase. Thus, Mps1 acts at the kinetochore to co-ordinate the successful attachment of a microtubule and the triggering of microtubule depolymerization to move the chromosome.

中文翻译：

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Mps1促进减数分裂中期的极点染色体运动

在减数分裂I的前期，同源伴侣染色体配对并通过交叉连接。Chiasmata，伙伴之间形成的连接使染色体对（称为二价）能够作为单个单元附着到纺锤体上。当减数分裂I纺锤体形成于前中期时，大多数二价与单个纺锤极相关联，并在纺锤上经历一系列振荡，附着在微管上或从微管上分离，直到二价的配偶体是双向的，即从纺锤体的相反侧向微管转移，并准备在后期I进行分离。保守的，与线粒体相关的激酶Mps1，对于二价被微管在前中期跨纺锤体拉动至关重要。在这里，我们显示MPS1不是动植物附着微管所必需的，而是触发微管附着的动物向极点迁移所必需的。我们的数据支持以下模型：一旦Mps1附着在前中期的动植物上，就会触发微管末端的解聚。因此，Mps1作用于动粒，以协调微管的成功附着和触发微管解聚以移动染色体。