Identification of a novel streptococcal gene cassette mediating SOS mutagenesis in Streptococcus uberis.

ABSTRACT: Streptococci have been considered to lack the classical SOS response, defined by increased mutation after UV exposure and regulation by LexA. Here we report the identification of a potential self-regulated SOS mutagenesis gene cassette in the Streptococcaceae family. Exposure to UV light was found to increase mutations to antibiotic resistance in Streptococcus uberis cultures. The mutational spectra revealed mainly G:C-->A:T transitions, and Northern analyses demonstrated increased expression of a Y-family DNA polymerase resembling UmuC under DNA-damaging conditions. In the absence of the Y-family polymerase, S. uberis cells were sensitive to UV light and to mitomycin C. Furthermore, the UV-induced mutagenesis was almost completely abolished in cells deficient in the Y-family polymerase. T

SUBMITTER: Varhimo E 

PROVIDER: S-EPMC1951879 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature