The ability of Sgs1 to interact with DNA topoisomerase III is essential for damage-induced recombination.
SGS1 encodes a protein having DNA helicase activity, and a mutant allele of SGS1 was identified as a suppressor of the slow growth phenotype of top3 mutants. In this study, we examined whether Sgs1 prevents formation of DNA double strand breaks (DSBs) or is involved in DSB repair following exposure to methyl methanesulfonate (MMS). An analysis by pulsed-field gel electrophoresis and epistasis analyses indicated that Sgs1 is required for DSB repair that involves Rad52. In addition, analyses on the relationship between Sgs1 and proteins involved in DSB repair suggested that Sgs1 and Mre11 function via independent pathways both of which require Rad52. In sgs1 mutants, interchromosomal heteroallelic recombination and sister chromatid recombination (SCR) were not induced upon exposure to MMS, though both were induced in wild type cells, indicating the involvement of Sgs1 in heteroallelic recombination and SCR. Surprisingly, the ability of Sgs1 to bind to DNA topoisomerase III (Top3) was absolutely required for the induction of heteroallelic recombination and SCR and suppression of MMS sensitivity but its helicase activity was not, suggesting that Top3 plays a more important role in both recombinations than the DNA helicase activity of Sgs1.
Ui
Ayako
A
Molecular Cell Biology Laboratory, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
Seki
Masayuki
M
Ogiwara
Hideaki
H
Onodera
Ryoko
R
Fukushige
Shin-ichi
S
Onoda
Fumitoshi
F
Enomoto
Takemi
T
D000483:Alleles; D034961:Antigens, Nuclear / Q000378:metabolism; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism*; D004260:DNA Repair / Q000187:drug effects* / Q000235:genetics; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004271:DNA, Fungal / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000378:metabolism; D000072200:Ku Autoantigen; D008741:Methyl Methanesulfonate / Q000009:adverse effects; D051721:Rad52 DNA Repair and Recombination Protein; D053484:RecQ Helicases; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction; D012854:Sister Chromatid Exchange
D034961:Antigens, Nuclear; D004271:DNA, Fungal; D004268:DNA-Binding Proteins; C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; D008741:Methyl Methanesulfonate; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae; C090472:SGS1 protein, S cerevisiae; D004265:DNA Helicases; D053484:RecQ Helicases; D000072200:Ku Autoantigen; D004264:DNA Topoisomerases, Type I