Structure and DNA-bridging activity of the essential Rec114-Mei4 trimer interface

Area of Science:

• Molecular Biology
• Genetics
• Structural Biology

Background:

• Meiotic recombination initiates with DNA double-strand breaks (DSBs).
• Rec114 and Mei4 (RM) proteins are conserved factors regulating DSB formation spatially and temporally.
• In vivo, RM proteins form large foci integrated with chromosome structures; in vitro, they form heterotrimeric complexes that bind DNA and form condensates.

Purpose of the Study:

• To elucidate the atomic structures and dynamic DNA-binding properties of RM complexes.
• To understand the molecular mechanisms underlying RM-mediated condensate formation and DSB regulation.

Main Methods:

• Nuclear magnetic resonance (NMR) experiments to determine the structure of a minimal Rec114-Mei4 complex.
• Single-molecule experiments to analyze DNA-binding and force-generating capabilities.
• AlphaFold2 for predicting structural models of orthologous RM complexes.

Main Results:

• A structural model of a heterotrimeric Rec114 C-terminus/Mei4 N-terminus complex was determined, sufficient for DNA binding and condensate formation.
• The minimal complex bridges multiple DNA duplexes and generates force for DNA condensation via long-range interactions.
• AlphaFold2 successfully predicted conserved structural models for diverse RM orthologs.

Conclusions:

• The minimal Rec114-Mei4 complex reveals conserved protein-protein and protein-DNA interactions driving condensate formation.
• These interactions are critical for regulating meiotic DSB formation and ensuring proper recombination.
• Structural insights into RM complexes advance understanding of meiotic processes and genome stability.