The in vivo characterization of translesion synthesis across UV-induced lesions in Saccharomyces cerevisiae: insights into Pol zeta- and Pol eta-dependent frameshift mutagenesis.
UV irradiation, a known carcinogen, induces the formation of dipyrimidine dimers with the predominant lesions being cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone adducts (6-4PPs). The relative roles of the yeast translesion synthesis DNA polymerases Pol zeta and Pol eta in UV survival and mutagenesis were examined using strains deficient in one or both polymerases. In addition, photoreactivation was used to specifically remove CPDs, thus allowing an estimate to be made of the relative contributions of CPDs vs. 6-4PPs to overall survival and mutagenesis. In terms of UV-induced mutagenesis, we focused on the +1 frameshift mutations detected by reversion of the lys2deltaA746 allele, as Pol zeta produces a distinct mutational signature in this assay. Results suggest that CPDs are responsible for most of the UV-associated toxicity as well as for the majority of UV-induced frameshift mutations in yeast. Although the presence of Pol eta generally suppresses UV-induced mutagenesis, our data suggest a role for this polymerase in generating some classes of +1 frameshifts. Finally, the examination of frameshift reversion spectra indicates a hierarchy between Pol eta and Pol zeta with respect to the bypass of UV-induced lesions.
Abdulovic
Amy L
AL
Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia 30322, USA.
Jinks-Robertson
Sue
S
D001483:Base Sequence; D004260:DNA Repair / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis / Q000235:genetics* / Q000502:physiology; D004307:Dose-Response Relationship, Radiation; D016368:Frameshift Mutation; D017353:Gene Deletion; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000528:radiation effects*; D014466:Ultraviolet Rays; D000099270:Y-Family DNA Polymerases
D004259:DNA-Directed DNA Polymerase; C425929:DNA polymerase zeta; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases