Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo 192-0397, Japan.
Biomolecules. 2022 Nov 26;12(12):1761. doi: 10.3390/biom12121761.
Meiotic recombination is a pivotal event that ensures faithful chromosome segregation and creates genetic diversity in gametes. Meiotic recombination is initiated by programmed double-strand breaks (DSBs), which are catalyzed by the conserved Spo11 protein. Spo11 is an enzyme with structural similarity to topoisomerase II and induces DSBs through the nucleophilic attack of the phosphodiester bond by the hydroxy group of its tyrosine (Tyr) catalytic residue. DSBs caused by Spo11 are repaired by homologous recombination using homologous chromosomes as donors, resulting in crossovers/chiasmata, which ensure physical contact between homologous chromosomes. Thus, the site of meiotic recombination is determined by the site of the induced DSB on the chromosome. Meiotic recombination is not uniformly induced, and sites showing high recombination rates are referred to as recombination hotspots. In fission yeast, , a nonsense point mutation of is a well-characterized meiotic recombination hotspot caused by the heptanucleotide sequence 5'-ATGACGT-3' at the mutation point. In this review, we summarize the meiotic recombination mechanisms revealed by the analysis of the fission gene as a model system.
减数分裂重组是一个关键事件，它确保了染色体的正确分离，并在配子中创造了遗传多样性。减数分裂重组是由有丝分裂的双链断裂（DSB）引发的，这些双链断裂是由保守的 Spo11 蛋白催化的。Spo11 是一种与拓扑异构酶 II 具有结构相似性的酶，通过其酪氨酸（Tyr）催化残基的羟基对磷酸二酯键的亲核攻击诱导 DSB。由 Spo11 引起的 DSB 通过同源染色体作为供体进行同源重组修复，导致交叉/交叉，从而确保同源染色体之间的物理接触。因此，减数分裂重组的位点由染色体上诱导的 DSB 位点决定。减数分裂重组不是均匀诱导的，显示高重组率的位点称为重组热点。在裂殖酵母中，一个无义点突变 是一个由突变点处的七核苷酸序列 5'-ATGACGT-3'引起的、特征明确的减数分裂重组热点。在这篇综述中，我们总结了裂殖酵母 基因作为模型系统的分析所揭示的减数分裂重组机制。
