Proteasomal regulation of the mutagenic translesion DNA polymerase, Saccharomyces cerevisiae Rev1
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Walker_Proteasomal regulation.pdf
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Author(s)
Wiltrout, Mary Ellen
Walker, Graham C.
Date Issued
January 2011
Journal
DNA Repair
Publisher
Elsevier
Citation
Wiltrout, Mary Ellen, and Graham C. Walker. “Proteasomal Regulation of the Mutagenic Translesion DNA Polymerase, Saccharomyces Cerevisiae Rev1.” DNA Repair 10, no. 2 (February 2011): 169–175.
Version
Author's final manuscript
Abstract
Translesion DNA synthesis (TLS) functions as a tolerance mechanism for DNA damage at a potentially mutagenic cost. Three TLS polymerases (Pols) function to bypass DNA damage in Saccharomyces cerevisiae: Rev1, Pol ζ, a heterodimer of the Rev3 and Rev7 proteins, and Pol η (Rad30). Our lab has shown that S. cerevisiae Rev1 protein levels are under striking cell cycle regulation, being ~50-fold higher during G2/M than during G1 and much of S phase (Waters and Walker, 2006). REV1 transcript levels only vary ~3-fold in a similar cell cycle pattern, suggesting a posttranscriptional mechanism controls protein levels. Here, we show that the S. cerevisiae Rev1 protein is unstable during both the G1 and the G2/M phases of the cell cycle, however, the protein's half-life is shorter in G1 arrested cells than in G2/M arrested cells, indicating that the rate of proteolysis strongly contributes to Rev1's cell cycle regulation. In the presence of the proteasome inhibitor, MG132, the steady-state levels and half-life of Rev1 increase during G1 and G2/M. Through the use of a viable proteasome mutant, we confirm that the levels of Rev1 protein are dependent on proteasome-mediated degradation. The accumulation of higher migrating forms of Rev1 under certain conditions shows that the degradation of Rev1 is possibly directed through the addition of a polyubiquitination signal or another modification. These results support a model that proteasomal degradation acts as a regulatory system of mutagenic TLS mediated by Rev1.
MIT Department
Massachusetts Institute of Technology. Department of Biology
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DOI of Published Version
https://doi.org/10.1016/j.dnarep.2010.10.008
