Abstract
Fun30 is a Swi2/Snf2 homolog in budding yeast that has been shown to remodel chromatin both in vitro and in vivo. We report that Fun30 plays a key role in homologous recombination, by facilitating 5'-to-3' resection of double-strand break (DSB) ends, apparently by facilitating exonuclease digestion of nucleosome-bound DNA adjacent to the DSB. Fun30 is recruited to an HO endonuclease-induced DSB and acts in both the Exo1-dependent and Sgs1-dependent resection pathways. Deletion of FUN30 slows the rate of 5'-to-3' resection from 4 kb/h to about 1.2 kb/h. We also found that the resection rate is reduced by DNA damage-induced phosphorylation of histone H2A-S129 (γ-H2AX) and that Fun30 interacts preferentially with nucleosomes in which H2A-S129 is not phosphorylated. Fun30 is not required for later steps in homologous recombination. Like its homolog Rdh54/Tid1, Fun30 is required to allow the adaptation of DNA damage checkpoint-arrested cells with an unrepaired DSB to resume cell cycle progression.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Adaptation, Physiological
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Cell Cycle Checkpoints / genetics
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Chromatin / genetics
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Chromatin / metabolism*
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Chromatin Assembly and Disassembly
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DNA Breaks, Double-Stranded
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DNA, Fungal / genetics
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DNA, Fungal / metabolism*
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Exodeoxyribonucleases / genetics
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Exodeoxyribonucleases / metabolism
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Histones / genetics
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Histones / metabolism
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Homologous Recombination
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Nucleosomes / genetics
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Nucleosomes / metabolism
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Phosphorylation
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RecQ Helicases / genetics
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RecQ Helicases / metabolism
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / metabolism*
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Saccharomyces cerevisiae Proteins / genetics
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Saccharomyces cerevisiae Proteins / metabolism*
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Sequence Homology, Amino Acid
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Signal Transduction
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Transcription Factors / genetics
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Transcription Factors / metabolism*
Substances
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Chromatin
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DNA, Fungal
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FUN30 protein, S cerevisiae
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Histones
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Nucleosomes
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Saccharomyces cerevisiae Proteins
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Transcription Factors
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Exodeoxyribonucleases
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exodeoxyribonuclease I
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SGS1 protein, S cerevisiae
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RecQ Helicases