A hallmark of the Escherichia coli SOS response is the large increase in mutations caused by translesion synthesis (TLS). TLS requires DNA polymerase V (UmuD′ 2C) and RecA. Here, we show that pol V and RecA interact by two distinct mechanisms. First, pol V binds to RecA in the absence of DNA and ATP and second, through its UmuD′ subunit, requiring DNA and ATP without ATP hydrolysis. TLS occurs in the absence of a RecA nucleoprotein filament but is inhibited in its presence. Therefore, a RecA nucleoprotein filament is unlikely to be required for SOS mutagenesis. Pol V activity is severely diminished in the absence of RecA or in the presence of RecA1730, a mutant defective for pol V mutagenesis in vivo. Pol V activity is strongly enhanced with RecA mutants constitutive for mutagenesis in vivo, suggesting that RecA is an obligate accessory factor that activates pol V for SOS mutagenesis.

doi.org/10.1016/j.molcel.2005.01.006, hdl.handle.net/1765/56504
Molecular Cell
Department of Radiation Oncology

Schlacher, K., Leslie, K., Wyman, C., Woodgate, R., Cox, M., & Goodman, M. (2005). DNA polymerase V and RecA protein, a minimal mutasome. Molecular Cell, 17(4), 561–572. doi:10.1016/j.molcel.2005.01.006