Roles of RAD6 epistasis group members in spontaneous polzeta-dependent translesion synthesis in Saccharomyces cerevisiae.
DNA lesions that arise during normal cellular metabolism can block the progress of replicative DNA polymerases, leading to cell cycle arrest and, in higher eukaryotes, apoptosis. Alternatively, such blocking lesions can be temporarily tolerated using either a recombination- or a translesion synthesis-based bypass mechanism. In Saccharomyces cerevisiae, members of the RAD6 epistasis group are key players in the regulation of lesion bypass by the translesion DNA polymerase Polzeta. In this study, changes in the reversion rate and spectrum of the lys2DeltaA746 -1 frameshift allele have been used to evaluate how the loss of members of the RAD6 epistasis group affects Polzeta-dependent mutagenesis in response to spontaneous damage. Our data are consistent with a model in which Polzeta-dependent mutagenesis relies on the presence of either Rad5 or Rad18, which promote two distinct error-prone pathways that partially overlap with respect to lesion specificity. The smallest subunit of Poldelta, Pol32, is also required for Polzeta-dependent spontaneous mutagenesis, suggesting a cooperative role between Poldelta and Polzeta for the bypass of spontaneous lesions. A third error-free pathway relies on the presence of Mms2, but may not require PCNA.
Minesinger
Brenda K
BK
Biochemistry, Cell and Developmental Biology Program of the Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, GA 30322, USA.
Jinks-Robertson
Sue
S
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000483:Alleles; D001483:Base Sequence; D004265:DNA Helicases; D004258:DNA Polymerase III / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D004843:Epistasis, Genetic; D016368:Frameshift Mutation; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009010:Monte Carlo Method; D016296:Mutagenesis; D009154:Mutation; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011485:Protein Binding; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics* / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases
D004268:DNA-Binding Proteins; C112520:MMS2 protein, S cerevisiae; D018809:Proliferating Cell Nuclear Antigen; C063607:RAD18 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C471606:RAD6 protein, S cerevisiae; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; C425929:DNA polymerase zeta; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D000251:Adenosine Triphosphatases; C076225:RAD5 protein, S cerevisiae; D004265:DNA Helicases