Related Experiment Video
Updated: Sep 17, 2025
06:24
Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51
Published on: February 13, 2019
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A large C-terminal Rad52 segment acts as a chaperone to Form and Stabilize Rad51 Filaments
Emilie Ma1,2, Fadma Lakhal3, Eleni Litsardaki4,5
1Université Paris Cité, Inserm, CEA, Stabilité Génétique Cellules Souches et Radiations, LRGM/iRCM/IBFJ, F-92260, Fontenay-aux-Roses, France.
Nature Communications
|July 2, 2025
Summary
Rad52 acts as a crucial assembly chaperone for Rad51 nucleofilament formation, essential for DNA repair. Structural and functional studies reveal how Rad52
Area of Science:
- Molecular biology
- Structural biology
- Genetics
Background:
- Homologous recombination (HR) is vital for DNA double-strand break repair and replication fork restart.
- Rad51 nucleofilament formation is a critical step in HR, enabling homology search and strand invasion.
- In yeast, Rad52 facilitates Rad51 nucleofilament assembly and counteracts Srs2-mediated dissociation, but the molecular mechanisms are unclear.
Purpose of the Study:
- To elucidate the molecular basis of Rad52's functions in Rad51 nucleofilament formation.
- To characterize the structural interaction between Rad52 and Rad51.
- To determine the role of a conserved Rad52 segment in Rad51 filament assembly and stability.
Main Methods:
- Integrative structural analyses using Nuclear Magnetic Resonance (NMR), Small-Angle X-ray Scattering (SAXS), and computational modeling.
- Site-directed mutagenesis to validate the identified Rad51-Rad52 binding mode.
- In vivo assays and functional fluorescent protein (GFP-Rad51) studies to assess Rad51 filament formation.
Main Results:
- An 85-residue segment of Rad52, conserved in fungi, folds upon binding to Rad51, featuring an FxxA motif.
- This Rad52 segment binds to a broad surface of Rad51, influencing its assembly.
- Mutational analysis and in vivo assays confirmed the critical role of this segment in Rad51 filament formation and stability.
Conclusions:
- Rad52 functions as an assembly chaperone for Rad51, preventing oligomerization and promoting ssDNA nucleation.
- The identified Rad52 segment is essential for counteracting Srs2's destabilizing effects on Rad51 filaments.
- These findings provide molecular insights into Rad52's role in facilitating DNA repair through Rad51 nucleofilament dynamics.
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