title: Saccharomyces cerevisiae RAD53 (CHK2) but not CHK1 is required for double-strand break-initiated SCE and DNA damage-associated SCE after exposure to X rays and chemical agents.
abstract: Saccharomyces cerevisiae RAD53 (CHK2) and CHK1 control two parallel branches of the RAD9-mediated pathway for DNA damage-induced G(2) arrest. Previous studies indicate that RAD9 is required for X-ray-associated sister chromatid exchange (SCE), suppresses homology-directed translocations, and is involved in pathways for double-strand break repair (DSB) repair that are different than those controlled by PDS1. We measured DNA damage-associated SCE in strains containing two tandem fragments of his3, his3-Delta5' and his3-Delta3'::HOcs, and rates of spontaneous translocations in diploids containing GAL1::his3-Delta5' and trp1::his3-Delta3'::HOcs. DNA damage-associated SCE was measured after log phase cells were exposed to methyl methanesulfonate (MMS), 4-nitroquinoline 1-oxide (4-NQO), UV, X rays and HO-induced DSBs. We observed that rad53 mutants were defective in MMS-, 4-NQO, X-ray-associated and HO-induced SCE but not in UV-associated SCE. Similar to rad9 pds1 double mutants, rad53 pds1 double mutants exhibited more X-ray sensitivity than the single mutants. rad53 sml1 diploid mutants exhibited a 10-fold higher rate of spontaneous translocations compared to the sml1 diploid mutants. chk1 mutants were not deficient in DNA damage-associated SCE after exposure to DNA damaging agents or after DSBs were generated at trp1::his3-Delta5'his3-Delta3'::HOcs. These data indicate that RAD53, not CHK1, is required for DSB-initiated SCE, and DNA damage-associated SCE after exposure to X-ray-mimetic and UV-mimetic chemicals.
authors.affiliation: Ordway Research Institute, 150 New Scotland Avenue, Albany, New York 12208, USA. mfasullo@ordwayresearch.org
authors.forename: Michael
authors.initials: M
authors.lastname: Fasullo
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dong
authors.forename: Mingzeng
authors.initials: M
authors.lastname: Sun
authors.forename: Li
authors.initials: L
authors.lastname: Zeng
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000633:toxicity; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D000071877:Checkpoint Kinase 1; D064447:Checkpoint Kinase 2; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D008741:Methyl Methanesulfonate / Q000633:toxicity; D009153:Mutagens / Q000633:toxicity; D011494:Protein Kinases / Q000235:genetics / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D011995:Recombination, Genetic / Q000187:drug effects / Q000528:radiation effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000502:physiology*; D012854:Sister Chromatid Exchange / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D014466:Ultraviolet Rays; D014965:X-Rays
chemical_list: D018797:Cell Cycle Proteins; D009153:Mutagens; D029701:Saccharomyces cerevisiae Proteins; D015112:4-Nitroquinoline-1-oxide; D008741:Methyl Methanesulfonate; D011494:Protein Kinases; D064447:Checkpoint Kinase 2; D000071877:Checkpoint Kinase 1; D017346:Protein Serine-Threonine Kinases; C067022:RAD53 protein, S cerevisiae; C530845:HO protein, S cerevisiae; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific