Effects of accessory proteins on the bypass of a cis-syn thymine-thymine dimer by Saccharomyces cerevisiae DNA polymerase eta.

ABSTRACT: Among several hypotheses to explain how translesion synthesis (TLS) by DNA polymerase eta (pol eta) suppresses ultraviolet light-induced mutagenesis in vivo despite the fact that pol eta copies DNA with low fidelity, here we test whether replication accessory proteins enhance the fidelity of TLS by pol eta. We first show that the single-stranded DNA binding protein RPA, the sliding clamp PCNA, and the clamp loader RFC slightly increase the processivity of yeast pol eta and its ability to recycle to new template primers. However, these increases are small, and they are similar when copying an undamaged template and a template containing a cis-syn TT dimer. Consequently, the accessory proteins do not strongly stimulate the already robust TT dimer bypass efficiency of pol eta. We then perform

SUBMITTER: McCulloch SD 

PROVIDER: S-EPMC2288658 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature