Ito Masaru, Shinohara Akira
Institute for Protein Research, Osaka University, Suita, Osaka, Japan.
Front Cell Dev Biol. 2023 Jan 6;10:1097446. doi: 10.3389/fcell.2022.1097446. eCollection 2022.
Meiocytes organize higher-order chromosome structures comprising arrays of chromatin loops organized at their bases by linear axes. As meiotic prophase progresses, the axes of homologous chromosomes align and synapse along their lengths to form ladder-like structures called synaptonemal complexes (SCs). The entire process of meiotic recombination, from initiation programmed DNA double-strand breaks (DSBs) to completion of DSB repair with crossover or non-crossover outcomes, occurs in the context of chromosome axes and SCs. These meiosis-specific chromosome structures provide specialized environments for the regulation of DSB formation and crossing over. In this review, we summarize insights into the importance of chromosome architecture in the regulation of meiotic recombination, focusing on cohesin-mediated axis formation, DSB regulation tethered loop-axis complexes, inter-homolog template bias facilitated by axial proteins, and crossover regulation in the context of the SCs. We also discuss emerging evidence that the SUMO and the ubiquitin-proteasome system function in the organization of chromosome structure and regulation of meiotic recombination.
减数分裂细胞组织形成高阶染色体结构,该结构由染色质环阵列组成,这些染色质环在其基部由线性轴组织排列。随着减数分裂前期的进展,同源染色体的轴沿其长度方向对齐并发生联会,形成称为联会复合体(SCs)的梯状结构。减数分裂重组的整个过程,从起始的程序性DNA双链断裂(DSBs)到DSB修复以交叉或非交叉结果完成,都发生在染色体轴和SCs的背景下。这些减数分裂特异性染色体结构为DSB形成和交叉互换的调控提供了特殊环境。在本综述中,我们总结了关于染色体结构在减数分裂重组调控中的重要性的见解,重点关注黏连蛋白介导的轴形成、与环 - 轴复合体相连的DSB调控、由轴蛋白促进的同源模板偏向以及SCs背景下的交叉互换调控。我们还讨论了新出现的证据,即小泛素样修饰蛋白(SUMO)和泛素 - 蛋白酶体系统在染色体结构组织和减数分裂重组调控中发挥作用。