Multiple recombination pathways for sister chromatid exchange in Saccharomyces cerevisiae: role of RAD1 and the RAD52 epistasis group genes.
Sister chromatid exchange (SCE) can occur by several recombination mechanisms, including those directly initiated by double-strand breaks (DSBs), such as gap repair and break-induced replication (BIR), and those initiated when DNA polymerases stall, such as template switching. To elucidate SCE recombination mechanisms, we determined whether spontaneous and DNA damage-associated SCE requires specific genes within the RAD52 and RAD3 epistasis groups in Saccharomyces cerevisiae strains containing two his3 fragments, his3-Delta5' and his3-Delta3'::HOcs. SCE frequencies were measured after cells were exposed to UV, X-rays, 4-nitroquinoline 1-oxide (4-NQO) and methyl methanesulfonate (MMS), or when an HO endonuclease-induced DSB was introduced at his3-Delta3'::HOcs. Our data indicate that genes involved in gap repair, such as RAD55, RAD57 and RAD54, are required for DNA damage-associated SCE but not for spontaneous SCE. RAD50 and RAD59, genes required for BIR, are required for X-ray-associated SCE but not for SCE stimulated by HO-induced DSBs. In comparison with wild type, rates of spontaneous SCE are 10-fold lower in rad51 rad1 but not in either rad51 rad50 or rad51 rad59 double mutants. We propose that gap repair mechanisms are important in DNA damage-associated recombination, whereas alternative pathways, including a template switch pathway, play a role in spontaneous SCE.
Center for Immunology and Microbial Disease, Albany Medical College, 47 New Scotland Avenue, Albany, NY 12208-3479, USA.
Zheng
Z
Dong
Michael
M
Fasullo
D015112:4-Nitroquinoline-1-oxide / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D004265:DNA Helicases; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D015252:Deoxyribonucleases, Type II Site-Specific / Q000235:genetics / Q000378:metabolism; D004720:Endonucleases / Q000235:genetics / Q000502:physiology; D004843:Epistasis, Genetic; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D009154:Mutation; D015363:Quinolones / Q000494:pharmacology; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D011995:Recombination, Genetic / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012854:Sister Chromatid Exchange / Q000235:genetics*; D014466:Ultraviolet Rays; D014965:X-Rays
C120195:4-nitroquinolone-1-oxide; D004268:DNA-Binding Proteins; D015363:Quinolones; C086930:RAD50 protein, S cerevisiae; C497197:RAD52 protein, S cerevisiae; C400213:RAD59 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; D015112:4-Nitroquinoline-1-oxide; D008741:Methyl Methanesulfonate; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase; D004720:Endonucleases; C069266:RAD1 protein, S cerevisiae; C530845:HO protein, S cerevisiae; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific; C075468:RAD54 protein, S cerevisiae; D004265:DNA Helicases; D045643:DNA Repair Enzymes