Abstract
Eukaryotes have acquired many mechanisms to repair DNA double-strand breaks (DSBs) [1]. In the yeast Saccharomyces cerevisiae, this damage can be repaired either by homologous recombination, which depends on the Rad52 protein, or by non-homologous end-joining (NHEJ), which depends on the proteins yKu70 and yKu80 [2,3]. How do cells choose which repair pathway to use? Deletions of the SIR2, SIR3 and SIR4 genes - which are involved in transcriptional silencing at telomeres and HM mating-type loci (HMLα and HMRa) in yeast [4] - have been reported to reduce NHEJ as severely as deletions of genes encoding Ku proteins [5]. Here, we report that the effect of deleting SIR genes is largely attributable to derepression of silent mating-type genes, although Sir proteins do play a minor role in end-joining. When DSBs were made on chromosomes in haploid cells that retain their mating type, sirΔ mutants reduced the frequency of NHEJ by twofold or threefold, although plasmid end-joining was not affected. In diploid cells, sir mutants showed a twofold reduction in the frequency of NHEJ in two assays. Mating type also regulated the efficiency of DSB-induced homologous recombination. In MATa/MATα diploid cells, a DSB induced by HO endonuclease was repaired 98% of the time by gene conversion with the homologous chromosome, whereas in diploid cells with an α mating type (matΔ/MATΔ) repair succeeded only 82% of the time. Mating-type regulation of genes specific to haploid or diploid cells plays a key role in determining which pathways are used to repair DSBs.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 767-770 |
| Number of pages | 4 |
| Journal | Current Biology |
| Volume | 9 |
| Issue number | 14 |
| DOIs | |
| State | Published - Jul 15 1999 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
Cite this
Role of yeast SIR genes and mating type in directing DNA double-strand breaks to homologous and non-homologous repair paths. / Lee, Sang; Pâques, Frédéric; Sylvan, Jason; Haber, James E.
In: Current Biology, Vol. 9, No. 14, 15.07.1999, p. 767-770.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Role of yeast SIR genes and mating type in directing DNA double-strand breaks to homologous and non-homologous repair paths
AU - Lee, Sang
AU - Pâques, Frédéric
AU - Sylvan, Jason
AU - Haber, James E.
PY - 1999/7/15
Y1 - 1999/7/15
N2 - Eukaryotes have acquired many mechanisms to repair DNA double-strand breaks (DSBs) [1]. In the yeast Saccharomyces cerevisiae, this damage can be repaired either by homologous recombination, which depends on the Rad52 protein, or by non-homologous end-joining (NHEJ), which depends on the proteins yKu70 and yKu80 [2,3]. How do cells choose which repair pathway to use? Deletions of the SIR2, SIR3 and SIR4 genes - which are involved in transcriptional silencing at telomeres and HM mating-type loci (HMLα and HMRa) in yeast [4] - have been reported to reduce NHEJ as severely as deletions of genes encoding Ku proteins [5]. Here, we report that the effect of deleting SIR genes is largely attributable to derepression of silent mating-type genes, although Sir proteins do play a minor role in end-joining. When DSBs were made on chromosomes in haploid cells that retain their mating type, sirΔ mutants reduced the frequency of NHEJ by twofold or threefold, although plasmid end-joining was not affected. In diploid cells, sir mutants showed a twofold reduction in the frequency of NHEJ in two assays. Mating type also regulated the efficiency of DSB-induced homologous recombination. In MATa/MATα diploid cells, a DSB induced by HO endonuclease was repaired 98% of the time by gene conversion with the homologous chromosome, whereas in diploid cells with an α mating type (matΔ/MATΔ) repair succeeded only 82% of the time. Mating-type regulation of genes specific to haploid or diploid cells plays a key role in determining which pathways are used to repair DSBs.
AB - Eukaryotes have acquired many mechanisms to repair DNA double-strand breaks (DSBs) [1]. In the yeast Saccharomyces cerevisiae, this damage can be repaired either by homologous recombination, which depends on the Rad52 protein, or by non-homologous end-joining (NHEJ), which depends on the proteins yKu70 and yKu80 [2,3]. How do cells choose which repair pathway to use? Deletions of the SIR2, SIR3 and SIR4 genes - which are involved in transcriptional silencing at telomeres and HM mating-type loci (HMLα and HMRa) in yeast [4] - have been reported to reduce NHEJ as severely as deletions of genes encoding Ku proteins [5]. Here, we report that the effect of deleting SIR genes is largely attributable to derepression of silent mating-type genes, although Sir proteins do play a minor role in end-joining. When DSBs were made on chromosomes in haploid cells that retain their mating type, sirΔ mutants reduced the frequency of NHEJ by twofold or threefold, although plasmid end-joining was not affected. In diploid cells, sir mutants showed a twofold reduction in the frequency of NHEJ in two assays. Mating type also regulated the efficiency of DSB-induced homologous recombination. In MATa/MATα diploid cells, a DSB induced by HO endonuclease was repaired 98% of the time by gene conversion with the homologous chromosome, whereas in diploid cells with an α mating type (matΔ/MATΔ) repair succeeded only 82% of the time. Mating-type regulation of genes specific to haploid or diploid cells plays a key role in determining which pathways are used to repair DSBs.
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UR - http://www.scopus.com/inward/citedby.url?scp=0033565609&partnerID=8YFLogxK
U2 - 10.1016/S0960-9822(99)80339-X
DO - 10.1016/S0960-9822(99)80339-X
M3 - Article
C2 - 10421582
AN - SCOPUS:0033565609
VL - 9
SP - 767
EP - 770
JO - Current Biology
JF - Current Biology
SN - 0960-9822
IS - 14
ER -