Aberrant double-strand break repair in rad51 mutants of Saccharomyces cerevisiae.
A number of studies of Saccharomyces cerevisiae have revealed RAD51-independent recombination events. These include spontaneous and double-strand break-induced recombination between repeated sequences, and capture of a chromosome arm by break-induced replication. Although recombination between inverted repeats is considered to be a conservative intramolecular event, the lack of requirement for RAD51 suggests that repair can also occur by a nonconservative mechanism. We propose a model for RAD51-independent recombination by one-ended strand invasion coupled to DNA synthesis, followed by single-strand annealing. The Rad1/Rad10 endonuclease is required to trim intermediates formed during single-strand annealing and thus was expected to be required for RAD51-independent events by this model. Double-strand break repair between plasmid-borne inverted repeats was less efficient in rad1 rad51 double mutants than in rad1 and rad51 strains. In addition, repair events were delayed and frequently associated with plasmid loss. Furthermore, the repair products recovered from the rad1 rad51 strain were primarily in the crossover configuration, inconsistent with conservative models for mitotic double-strand break repair.
Kang
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LE
Department of Microbiology and Institute of Cancer Research, Columbia University College of Physicians and Surgeons, New York, New York 10032, USA.
Symington
L S
LS
D004249:DNA Damage; D004254:DNA Nucleotidyltransferases / Q000235:genetics* / Q000378:metabolism; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005785:Gene Conversion; D007763:Lac Operon / Q000235:genetics; D008957:Models, Genetic; D009154:Mutation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D051135:Rad51 Recombinase; D011995:Recombination, Genetic / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D004254:DNA Nucleotidyltransferases; C495151:RAD51 protein, S cerevisiae; D051135:Rad51 Recombinase; C037725:SCEI protein, S cerevisiae; D015252:Deoxyribonucleases, Type II Site-Specific