Interactions between Mer2 tetramers

Details

Supervisors

Claeys Bouuaert, Corentin

Faculty

Faculté des sciences

Degree label

Master [120] en biochimie et biologie moléculaire et cellulaire, à finalité didactique

Abstract

Genetic diversity and chromosomal integrity during sexual reproduction depend on the precise formation of DNA double-strand breaks (DSBs) in meiosis. These breaks, orchestrated by specialized protein complexes, are critical for initiating homologous recombination. This project investigates Mer2, a key scaffold protein within the Rec114-Mei4-Mer2 (RMM) complex in Saccharomyces cerevisiae, and its role in coordinating DNA binding, protein interactions, and condensate formation to organize recombination hotspots. Using a combination of biochemical and biophysical approaches, the study explored the unique contributions of Mer2’s intrinsically disordered regions (IDRs). Condensation assays demonstrated that the N-terminal IDR facilitates protein-protein interactions required for forming higher-order assemblies, while the C-terminal IDR anchors Mer2 to DNA and stabilizes condensates essential for DSB formation. Advanced techniques such as Electrophoretic Mobility Shift Assays (EMSA), pull-down experiments, Atomic Force Microscopy (AFM), and mutagenesis experiments characterized and quantified these interactions. Mutagenesis identified critical residues within the IDRs essential for Mer2’s functionality, revealing their impact on protein-protein interactions and condensate formation. The findings support a mechanistic model where Mer2’s multivalent interactions create nucleoprotein condensates, localizing the DNA repair machinery at recombination hotspots.