Mutations in yeast Rad51 that partially bypass the requirement for Rad55 and Rad57 in DNA repair by increasing the stability of Rad51-DNA complexes.
Yeast Rad51 promotes homologous pairing and strand exchange in vitro, but this activity is inefficient in the absence of the accessory proteins, RPA, Rad52, Rad54 and the Rad55-Rad57 heterodimer. A class of rad51 alleles was isolated that suppresses the requirement for RAD55 and RAD57 in DNA repair, but not the other accessory factors. Five of the six mutations isolated map to the region of Rad51 that by modeling with RecA corresponds to one of the DNA-binding sites. The other mutation is in the N-terminus of Rad51 in a domain implicated in protein-protein interactions and DNA binding. The Rad51-I345T mutant protein shows increased binding to single- and double-stranded DNA, and is proficient in displacement of replication protein A (RPA) from single-stranded DNA, suggesting that the normal function of Rad55-Rad57 is promotion and stabilization of Rad51-ssDNA complexes.
Fortin
Gary S
GS
Institute of Cancer Research and Department of Microbiology, Columbia University College of Physicians and Surgeons, 701 W. 168th Street, New York, NY 10032, USA.
Symington
Lorraine S
LS
D000251:Adenosine Triphosphatases; D000483:Alleles; D000595:Amino Acid Sequence; D004254:DNA Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D045643:DNA Repair Enzymes; D004271:DNA, Fungal / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D005720:Gamma Rays; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D051135:Rad51 Recombinase; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C087191:RAD55 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D004254:DNA Nucleotidyltransferases; C495151:RAD51 protein, S cerevisiae; C495153:RAD51 protein, human; D051135:Rad51 Recombinase; D000251:Adenosine Triphosphatases; C071451:RAD57 protein, S cerevisiae; D045643:DNA Repair Enzymes