Mutations in the Saccharomyces cerevisiae CDC1 gene affect double-strand-break-induced intrachromosomal recombination.
To isolate Saccharomyces cerevisiae mutants defective in recombinational DNA repair, we constructed a strain that contains duplicated ura3 alleles that flank LEU2 and ADE5 genes at the ura3 locus on chromosome V. When a HO endonuclease cleavage site is located within one of the ura3 alleles, Ura+ recombination is increased over 100-fold in wild-type strains following HO induction from the GAL1, 10 promoter. This strain was used to screen for mutants that exhibited reduced levels of HO-induced intrachromosomal recombination without significantly affecting the spontaneous frequency of Ura+ recombination. One of the mutations isolated through this screen was found to affect the essential gene CDC1. This mutation, cdc1-100, completely eliminated HO-induced Ura+ recombination yet maintained both spontaneous preinduced recombination levels and cell viability, cdc1-100 mutants were moderately sensitive to killing by methyl methanesulfonate and gamma irradiation. The effect of the cdc1-100 mutation on recombinational double-strand break repair indicates that a recombinationally silent mechanism other than sister chromatid exchange was responsible for the efficient repair of DNA double-strand breaks.
Halbrook
J
J
ICOS Corporation, Bothell, Washington 98021.
Hoekstra
M F
MF
D000595:Amino Acid Sequence; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D004260:DNA Repair; D005656:Fungal Proteins / Q000235:genetics*; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D011995:Recombination, Genetic; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
C090459:CDC1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins