Recruitment of Mre11 to recombination sites during meiosis

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• The Mre11 nuclease is a key component of the conserved MRX complex, vital for DNA double-strand break (DSB) repair.
• During meiosis, the MRX complex, along with Rec114-Mei4 and Mer2, is essential for programmed DSB formation, initiating homologous recombination.

Purpose of the Study:

• To investigate the biophysical properties of Mre11 and its role in DNA repair and meiotic recombination.
• To elucidate the function of the Mre11 C-terminal intrinsically-disordered region (IDR) in these processes.

Main Methods:

• In vitro studies of Mre11 and MRX complex condensate formation.
• In vivo analysis of Mre11 foci formation during mitosis and meiosis.
• Biochemical assays to determine the role of the Mre11 IDR in protein interactions and recruitment.

Main Results:

• Mre11 and MRX complexes form DNA-dependent, hexanediol-sensitive condensates in vitro.
• Mre11 assembles into DNA damage-dependent foci in mitosis and DSB-independent foci in meiosis.
• The Mre11 C-terminal IDR is required for both in vitro condensate and in vivo foci formation.
• Mre11 IDR mediates interaction with Mer2 and enhances Mre11 recruitment and DSB formation during meiosis.

Conclusions:

• Mre11's intrinsically disordered region plays a critical role in organizing the DNA repair machinery through biomolecular condensation.
• The Mre11 IDR is essential for initiating meiotic recombination by facilitating protein recruitment and DSB formation.
• These findings offer insights into the biophysical mechanisms underlying DNA repair and meiotic recombination initiation.