A Rad52 homolog is required for RAD51-independent mitotic recombination in Saccharomyces cerevisiae.
With the use of an intrachromosomal inverted-repeat as a recombination reporter we have previously shown that mitotic recombination is dependent on the RAD52 gene. However, recombination was found to be reduced only 4-fold by mutation of RAD51, which encodes a homolog of bacterial RecA proteins. A rad51, which strain containing the recombination reporter was mutagenized to identify components of the RAD51-independent pathway. One mutation identified, rad59, reduced recombination 1200-fold in the presence of a rad51 mutation, but only 4- to 5-fold in a wild-type background. Thus the rad51 and rad59 mutations reduce recombination synergistically. The rad59 mutation reduced both spontaneous and double-strand-break-induced recombination between inverted repeats. However, the rate of interchromosomal recombination was increased in a rad59 homozygous diploid. These observations suggest that RAD59 functions specifically in intrachromosomal recombination. The rad59 mutant strain was sensitive to ionizing radiation, and this phenotype was used to clone the RAD59 gene by complementation. The gene encodes a protein of 238 amino acids with significant homology to members of the Rad52 family. Overexpression of RAD52 was found to suppress the DNA repair and recombination defects conferred by the rad59 mutation, suggesting that these proteins have overlapping roles or function as a complex.
Bai
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Y
Columbia University College of Physicians and Surgeons, Department of Microbiology and Institute of Cancer Research, New York, New York 10032, USA.
Symington
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LS
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology*; D005720:Gamma Rays; D005785:Gene Conversion; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008938:Mitosis; D008969:Molecular Sequence Data; D051135:Rad51 Recombinase; D051721:Rad52 DNA Repair and Recombination Protein; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase