Recruitment of the MRX Complex to Recombination Sites during Meiosis

The Mre11 nuclease is part of the highly conserved MRX complex involved in the repair of DNA  double-strand breaks (DSBs). During yeast meiosis, MRX is also required for the programmed induction of DSBs by Spo11, thereby initiating meiotic DNA recombination to promote the accurate segregation of homologous chromosomes. The recruitment of Mre11 during meiosis depends on Rec114-Mei4 and Mer2 (RMM), which are thought to organize the meiotic DSB machinery by a mechanism of biomolecular condensation. Here, we investigated the role of Mre11 during meiosis and its relationship to RMM condensation. We show that, like RMM, Mre11 and MRX complexes form DNA-dependent, hexanediol-sensitive, condensates in vitro. In vivo, Mre11 forms DNA damage-dependent foci in vegetative cells and DSB-independent foci in meiotic cells. In vitro condensates and in vivo foci both depend on the C-terminal intrinsically-disordered region (IDR) of Mre11. However, the IDR is dispensable for vegetative DNA repair, but essential during meiosis. The C-terminal end of Mre11 forms a short alpha-helix that binds a conserved sequence 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 promotes the recruitment of Mre11 during meiosis and facilitates DSB formation. Our results provide new insights into the biophysical properties of Mre11 and its unique role in initiating meiotic DNA recombination.

Priyadarshini P., et al. "Recruitment of Mre11 to recombination sites during meiosis" Nature Communications, in press (2026).
doi.org/10.1038/s41467-026-71310-