Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794, USA
Genes Dev. 2020 Dec 1;34(23-24):1562-1564. doi: 10.1101/gad.345488.120.
Proper segregation during meiosis requires that homologs be connected by the combination of crossovers and sister chromatid cohesion. To generate crossovers, numerous double-strand breaks (DSBs) are introduced throughout the genome by the conserved Spo11 endonuclease. DSB formation and its repair are then highly regulated to ensure that homologous chromosomes contain at least one crossover and no DSBs remain prior to meiosis I segregation. The synaptonemal complex (SC) is a meiosis-specific structure formed between homologous chromosomes during prophase that promotes DSB formation and biases repair of DSBs to homologs over sister chromatids. Synapsis occurs when a particular recombination pathway is successful in establishing stable interhomolog connections. In this issue of , Mu and colleagues (pp. 1605-1618) show that SC formation between individual chromosomes provides the feedback to down-regulate Spo11 activity, thereby revealing an additional function for the SC.
减数分裂过程中正确的分离需要通过交叉和姐妹染色单体黏合的组合将同源物连接起来。为了产生交叉，大量双链断裂（DSB）由保守的 Spo11 内切酶在整个基因组中引入。然后，DSB 的形成及其修复受到高度调控，以确保在减数分裂 I 分离之前同源染色体至少含有一个交叉，并且没有 DSB 残留。联会复合体（SC）是在前期形成于同源染色体之间的减数分裂特异性结构，它促进 DSB 的形成，并使 DSB 的修复偏向于同源染色体而非姐妹染色单体。当特定的重组途径成功建立稳定的异源连接时，就会发生联会。在本期的 杂志中，Mu 及其同事（第 1605-1618 页）表明，个体染色体之间的 SC 形成提供了下调 Spo11 活性的反馈，从而揭示了 SC 的另一个功能。
