Program in Cell Cycle and Cancer Biology, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104.
Department of Cell Biology, University of Oklahoma Health Science Center, Oklahoma City, OK 73104.
Proc Natl Acad Sci U S A. 2019 May 7;116(19):9417-9422. doi: 10.1073/pnas.1902526116. Epub 2019 Apr 24.
Faithful chromosome segregation during meiosis I depends upon the formation of connections between homologous chromosomes. Crossovers between homologs connect the partners, allowing them to attach to the meiotic spindle as a unit, such that they migrate away from one another at anaphase I. Homologous partners also become connected by pairing of their centromeres in meiotic prophase. This centromere pairing can promote proper segregation at anaphase I of partners that have failed to become joined by a crossover. Centromere pairing is mediated by synaptonemal complex (SC) proteins that persist at the centromere when the SC disassembles. Here, using mouse spermatocyte and yeast model systems, we tested the role of shugoshin in promoting meiotic centromere pairing by protecting centromeric synaptonemal components from disassembly. The results show that shugoshin protects the centromeric SC in meiotic prophase and, in anaphase, promotes the proper segregation of partner chromosomes that are not linked by a crossover.
减数分裂 I 中同源染色体间的联会对于染色体的正确分离至关重要。同源染色体间的交叉连接将配对的染色体连接在一起，使它们能够作为一个整体附着到减数分裂纺锤体上，从而在减数分裂后期 I 中彼此远离。同源染色体的配对还可以通过它们的着丝粒在减数分裂前期的配对来促进。这种着丝粒配对可以促进在未能通过交叉连接结合的同源染色体在减数分裂后期 I 中的正确分离。着丝粒配对是由联会复合体（SC）蛋白介导的，当 SC 解聚时，这些蛋白仍留在着丝粒上。在这里，我们使用小鼠精母细胞和酵母模型系统，通过保护着丝粒上的联会复合体成分不被解聚，来测试 Shugoshin 在促进减数分裂着丝粒配对中的作用。结果表明，Shugoshin 在减数分裂前期保护着丝粒 SC，并在后期促进未通过交叉连接连接的染色体伙伴的正确分离。
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