The Saccharomyces cerevisiae rev6-1 mutation, which inhibits both the lesion bypass and the recombination mode of DNA damage tolerance, is an allele of POL30,

The rev6-1 allele was isolated in a screen for mutants deficient for UV-induced reversion of the frameshift mutation his4-38. Preliminary testing showed that the rev6-1 mutant was substantially deficient for UV-induced reversion of arg4-17 and ilv1-92, and markedly UV sensitive. Unlike other REV genes, which encode DNA polymerases and an associated subunit, REV6 has been found to be identical to POL30, which encodes Proliferating Cell Nuclear Antigen (PCNA), the subunit of the homotrimeric sliding clamp, in which the rev6-1 mutation produces a G178S substitution. This substitution appears to abolish all DNA damage tolerance activities normally carried out by the RAD6/RAD18 pathway, including translesion replication by DNA polymerase/Rev1 and DNA polymerase , and the error-free, recombination-dependent component of this pathway, but has little effect on the growth rate, suggesting that G178S may prevent ubiquitination of lysine 164 in PCNA. We also find that rev6-1 mutation can be fully complemented by a centromere- containing, low copy-number, plasmid carrying POL30, despite the presumed occurrence in the mutant of sliding clamp assemblies that contain anywhere between one and three G178S PCNA monomers as well as the fully wild type species.

Key Words: DNA damage tolerance mechanisms, Proliferating cell nuclear antigen, RAD6/RAD18 pathway, Saccharomyces cerevisiae, rev6-1

This article has been cited by other articles:

				J. L. Parker, A. B. Bielen, I. Dikic, and H. D. Ulrich Contributions of ubiquitin- and PCNA-binding domains to the activity of Polymerase {eta} in Saccharomyces cerevisiae Nucleic Acids Res., February 16, 2007; 35(3): 881 - 889. [Abstract] [Full Text] [PDF]

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