Bouuaert Corentin Claeys, Priyadarshini Priyanka, Survi Mahesh, Mouloud Wael El Yazidi, Bohn Regina, Ballet Steven, Hunter Neil, Volkov Alexander
Université catholique de Louvain.
Vrije Universiteit Brussel.
Res Sq. 2025 Aug 19:rs.3.rs-7215871. doi: 10.21203/rs.3.rs-7215871/v1.
The Mre11 nuclease is part of the highly conserved MRX complex involved in the repair of DNA double-strand breaks (DSBs). During meiosis in budding yeast, MRX is also required for the programmed induction of DSBs by Spo11, thereby initiating homologous recombination to promote accurate chromosome segregation. Recruitment of Mre11 to meiotic DSB sites depends on Rec114-Mei4 and Mer2 (RMM), which are thought to organize the meiotic DSB machinery by a mechanism involving biomolecular condensation. Here, we explored the role of Mre11 during meiosis and its relationship to RMM condensation. We show that both Mre11 and MRX complexes form DNA-dependent, hexanediol sensitive condensates . , Mre11 assembles into DNA damage-dependent foci in vegetative cells and DSB-independent foci in meiotic cells. condensates and foci both depend on the C-terminal intrinsically-disordered region (IDR) of Mre11. Importantly, while the Mre11 IDR is dispensable for vegetative DNA repair it is essential during meiosis. The C-terminal region of Mre11 forms a short α-helix that binds a conserved region of Mer2, and mutating residues within this interface reduces Mre11 foci and DSB formation. Finally, we identified a SUMO-interacting motif within the Mre11 IDR that enhances recruitment of Mre11 during meiosis and facilitates DSB formation. Our results provide new insights into the biophysical properties of Mre11 and its role in initiating meiotic recombination.
Mre11核酸酶是高度保守的MRX复合物的一部分，参与DNA双链断裂（DSB）的修复。在芽殖酵母减数分裂过程中，MRX对于Spo11程序性诱导DSB也是必需的，从而启动同源重组以促进精确的染色体分离。Mre11募集到减数分裂DSB位点依赖于Rec114-Mei4和Mer2（RMM），它们被认为通过涉及生物分子凝聚的机制来组织减数分裂DSB机制。在这里，我们探讨了Mre11在减数分裂过程中的作用及其与RMM凝聚的关系。我们表明，Mre11和MRX复合物都形成DNA依赖性的、对己二醇敏感的凝聚物。此外，Mre11在营养细胞中组装成DNA损伤依赖性焦点，在减数分裂细胞中组装成DSB非依赖性焦点。凝聚物和焦点都依赖于Mre11的C端内在无序区域（IDR）。重要的是，虽然Mre11 IDR对于营养DNA修复是可有可无的，但在减数分裂过程中却是必不可少的。Mre11的C端区域形成一个短α螺旋，与Mer2的一个保守区域结合，该界面内的残基突变会减少Mre11焦点和DSB形成。最后，我们在Mre11 IDR内鉴定出一个SUMO相互作用基序，该基序在减数分裂过程中增强Mre11的募集并促进DSB形成。我们的结果为Mre11的生物物理特性及其在启动减数分裂重组中的作用提供了新的见解。
