Budding yeast Rad50, Mre11, Xrs2, and Hdf1, but not Rad52, are involved in the formation of deletions on a dicentric plasmid.
We have previously shown that the RAD50, RAD52, MRE11, XRS2, and HDF1 genes of Saccharomyces cervisiae are involved in the formation of deletions by illegitimate recombination on a monocentric plasmid. In this study, we investigated the effects of mutations of these genes on formation of deletions of a dicentric plasmid, in which DNA double-strand breaks are expected to occur frequently because the two centromeres are pulled to opposite poles in mitosis. We transformed yeast cells with a dicentric plasmid, and after incubation for a few division cycles, cells carrying deleted plasmids were detected using negative selection markers. Deletions occurred at a higher frequency than on the monocentric plasmid and there were short regions of homology at the recombination junctions as observed on the monocentric plasmid. In rad50, mre11, xrs2, and hdf1 mutants, the frequency of occurrence of deletions was reduced by about 50-fold, while in the rad52 mutant, it was comparable to that in the wild-type strain. The end-joining functions of Rad50, Mre11, Xrs2, and Hdf1, suggest that these proteins play important roles in the joining of DNA ends produced on the dicentric plasmid during mitosis.
Tsukamoto
Y
Y
Department of Molecular Biology, Institute of Medical Science, University of Tokyo, Japan.
Kato
J
J
Ikeda
H
H
D001483:Base Sequence; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; D005656:Fungal Proteins / Q000235:genetics; D017353:Gene Deletion; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D051721:Rad52 DNA Repair and Recombination Protein; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins
D004271:DNA, Fungal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C086930:RAD50 protein, S cerevisiae; C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; D029701:Saccharomyces cerevisiae Proteins; C086929:XRS2 protein, S cerevisiae; C520769:YKU70 protein, S cerevisiae; C081647:high affinity DNA-binding factor, S cerevisiae; D004706:Endodeoxyribonucleases; D005090:Exodeoxyribonucleases; C094191:MRE11 protein, S cerevisiae