Bacterial genes mutL, mutS, and dcm participate in repair of mismatches at 5-methylcytosine sites.

摘要: Certain amber mutations in the cI gene of bacteriophage lambda appear to recombine very frequently with nearby mutations. The aberrant included C-to-T transitions at second cytosine 59CC(A/T)GG sequences (which are subject methylation by bacterial methylase) and 59CCAG 59CAGG sequences. Excess cI+ recombinants arising crosses that utilize these attributable correction mismatches a very-short-patch (VSP) mismatch repair system. In present study I found two genes required for methyladenine-directed (long-patch) repair, mutL mutS, also functioned VSP repair; mutH mutU (uvrD) were dispensable. was greatly reduced dcm Escherichia coli mutant, which 5-methylcytosine not methylated. However, heteroduplexes prepared from DNA lacking repaired dcm+ bacteria. These results indicate product has function addition its methylase activity.