Cells expressing murine RAD52 splice variants favor sister chromatid repair.
The RAD52 gene is essential for homologous recombination in the yeast Saccharomyces cerevisiae. RAD52 is the archetype in an epistasis group of genes essential for DNA damage repair. By catalyzing the replacement of replication protein A with Rad51 on single-stranded DNA, Rad52 likely promotes strand invasion of a double-stranded DNA molecule by single-stranded DNA. Although the sequence and in vitro functions of mammalian RAD52 are conserved with those of yeast, one difference is the presence of introns and consequent splicing of the mammalian RAD52 pre-mRNA. We identified two novel splice variants from the RAD52 gene that are expressed in adult mouse tissues. Expression of these splice variants in tissue culture cells elevates the frequency of recombination that uses a sister chromatid template. To characterize this dominant phenotype further, the RAD52 gene from the yeast Saccharomyces cerevisiae was truncated to model the mammalian splice variants. The same dominant sister chromatid recombination phenotype seen in mammalian cells was also observed in yeast. Furthermore, repair from a homologous chromatid is reduced in yeast, implying that the choice of alternative repair pathways may be controlled by these variants. In addition, a dominant DNA repair defect induced by one of the variants in yeast is suppressed by overexpression of RAD51, suggesting that the Rad51-Rad52 interaction is impaired.
Thorpe
Peter H
PH
Department of Genetics and Development, Columbia University Medical Center, HHSC 1608, 701 West 168th St., New York, New York 10032, USA.
Marrero
Vanessa A
VA
Savitzky
Margaret H
MH
Sunjevaric
Ivana
I
Freeman
Tom C
TC
Rothstein
Rodney
R
D016475:3T3 Cells; D000483:Alleles; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D004260:DNA Repair; D005091:Exons; D005434:Flow Cytometry; D005720:Gamma Rays; D005787:Gene Frequency; D005799:Genes, Dominant; D014644:Genetic Variation; D007438:Introns; D051379:Mice; D008969:Molecular Sequence Data; D051721:Rad52 DNA Repair and Recombination Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011995:Recombination, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000254:growth & development / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012854:Sister Chromatid Exchange
C497197:RAD52 protein, S cerevisiae; D051721:Rad52 DNA Repair and Recombination Protein; C497196:Rad52 protein, mouse; D029701:Saccharomyces cerevisiae Proteins