MUTAGENESIS BY PROXIMITY TO THE RECA GENE OF ESCHERICHIA-COLI

Escherichia coli recA (Prtc) strains, which produce protease constitutive RecA proteins in the absence of DNA-damaging treatments, display an increased frequency of spontaneous mutations. These mutations occurred preferentially in the neighborhood of the recA gene. This cis-like mutagenic effect was observed in the recA, rexAB, phoE and bio genes. The localized mutagenesis can be explained by the ease with which RecA(Prtc) proteins are activated to the protease state, which implies that there should be a relatively high concentration of activated RecA protein near the recA gene, where the protein is synthesized. The unusually high frequency of mutation in the recA gene is a novel example of an overactive gene preferentially turning itself down by mutation. © 1990.