Dominant negative rat DNA polymerase beta mutants interfere with base excision repair in Saccharomyces cerevisiae.
DNA polymerase beta is one of the smallest known eukaryotic DNA polymerases. This polymerase has been very well characterized in vitro, but its functional role in vivo has yet to be determined. Using a novel competition assay in Escherichia coli, we isolated two DNA polymerase beta dominant negative mutants. When we overexpressed the dominant negative mutant proteins in Saccharomyces cerevisiae, the cells became sensitive to methyl methanesulfonate. Interestingly, overexpression of the same polymerase beta mutant proteins did not confer sensitivity to UV damage, strongly suggesting that the mutant proteins interfere with the process of base excision repair but not nucleotide excision repair in S. cerevisiae. Our data implicate a role for polymerase IV, the S. cerevisiae polymerase beta homolog, in base excision repair in S. cerevisiae.
Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
C A
CA
Clairmont
J B
JB
Sweasy
D000818:Animals; D004256:DNA Polymerase I / Q000502:physiology*; D004260:DNA Repair; D004926:Escherichia coli / Q000235:genetics; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D009154:Mutation; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014466:Ultraviolet Rays
D008741:Methyl Methanesulfonate; D004256:DNA Polymerase I