Abstract
Rad52 is a key factor for homologous recombination (HR) in yeast. Rad52 helps assemble Rad51-ssDNA nucleoprotein filaments that catalyze DNA strand exchange, and it mediates single-strand DNA annealing. We find that Rad52 has an even earlier function in HR in restricting DNA double-stranded break ends resection that generates 3′ single-stranded DNA (ssDNA) tails. In fission yeast, Exo1 is the primary resection nuclease, with the helicase Rqh1 playing a minor role. We demonstrate that the choice of two extensive resection pathways is regulated by Rad52. In rad52 cells, the resection rate increases from ∼3–5 kb/h up to ∼10–20 kb/h in an Rqh1-dependent manner, while Exo1 becomes dispensable. Budding yeast Rad52 similarly inhibits Sgs1-dependent resection. Single-molecule analysis with purified budding yeast proteins shows that Rad52 competes with Sgs1 for DNA end binding and inhibits Sgs1 translocation along DNA. These results identify a role for Rad52 in limiting ssDNA generated by end resection.
Original language | English (US) |
---|---|
Pages (from-to) | 699-711.e6 |
Journal | Molecular Cell |
Volume | 76 |
Issue number | 5 |
DOIs | |
State | Published - Dec 5 2019 |
Keywords
- DNA repair
- Rad52
- RecQ helicase
- double-strand break
- homologous recombination
- resection
- yeast
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology