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.
Keywords:
DNA repair; Rad52; RecQ helicase; double-strand break; homologous recombination; resection; yeast.
Copyright © 2019 Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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DNA Breaks, Double-Stranded*
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DNA Breaks, Single-Stranded*
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DNA Helicases / genetics
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DNA Helicases / metabolism
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DNA Repair*
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DNA, Fungal / genetics
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DNA, Fungal / metabolism*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Exodeoxyribonucleases / genetics
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Exodeoxyribonucleases / metabolism
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Gene Expression Regulation, Fungal
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Kinetics
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Mutation
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Protein Domains
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Protein Transport
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Rad52 DNA Repair and Recombination Protein / genetics
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Rad52 DNA Repair and Recombination Protein / metabolism*
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RecQ Helicases / genetics
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RecQ Helicases / metabolism
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Saccharomyces cerevisiae / enzymology*
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Schizosaccharomyces / enzymology*
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Schizosaccharomyces / genetics
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism*
Substances
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DNA, Fungal
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DNA-Binding Proteins
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RAD52 protein, S cerevisiae
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Rad52 DNA Repair and Recombination Protein
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Saccharomyces cerevisiae Proteins
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Schizosaccharomyces pombe Proteins
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rad52 protein, S pombe
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Exodeoxyribonucleases
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exodeoxyribonuclease I
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SGS1 protein, S cerevisiae
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DNA Helicases
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RecQ Helicases
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Rqh1 protein, S pombe