The Mre11-Rad50-Xrs2 protein complex facilitates homologous recombination-based double-strand break repair in Saccharomyces cerevisiae.
Saccharomyces cerevisiae mre11Delta mutants are profoundly deficient in double-strand break (DSB) repair, indicating that the Mre11-Rad50-Xrs2 protein complex plays a central role in the cellular response to DNA DSBs. In this study, we examined the role of the complex in homologous recombination, the primary mode of DSB repair in yeast. We measured survival in synchronous cultures following irradiation and scored sister chromatid and interhomologue recombination genetically. mre11Delta strains were profoundly sensitive to ionizing radiation (IR) throughout the cell cycle. Mutant strains exhibited decreased frequencies of IR-induced sister chromatid and interhomologue recombination, indicating a general deficiency in homologous recombination-based DSB repair. Since a nuclease-deficient mre11 mutant was not impaired in these assays, it appears that the role of the S. cerevisiae Mre11-Rad50-Xrs2 protein complex in facilitating homologous recombination is independent of its nuclease activities.
Bressan
D A
DA
Laboratory of Genetics, University of Wisconsin Medical School, Madison, Wisconsin 53706, USA.
Baxter
B K
BK
Petrini
J H
JH
D000818:Animals; D004260:DNA Repair; D004268:DNA-Binding Proteins; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005720:Gamma Rays; D017353:Gene Deletion; D007399:Interphase; D046911:Macromolecular Substances; D000072235:Mating Factor; D009154:Mutation; D010455:Peptides / Q000494:pharmacology; D011836:Radiation Tolerance; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D046911:Macromolecular Substances; D010455:Peptides; C086930:RAD50 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C086929:XRS2 protein, S cerevisiae; D000072235:Mating Factor; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae