Conditional induction ofλprophage inexrAmutants ofEscherichia coli

Abstract

SUMMARYStrains ofEscherichia coliwhich contain the UV sensitivity geneexrA, repress UV induction ofλprophage in a novel manner. WhileexrA+strains can be induced by UV irradiation and express this induction in a 2 h period,exrAmutants delay the expression of induction for almost 4 h, and the induction maximum is approximately 10% of the wild-type value. The kinetics of the delayed induction and superinfection experiments indicate that the lifting of immunity and induction ofλprophage occur simultaneously.