Prophage induction inEscherichia coli K12 cells deficient in DNA polymerase I

Abstract

The induction of prophage λ by ultraviolet light has been measured inE. coli K12 lysogenic cells deficient in DNA polymerase I. The efficiency of the induction process was greater inpolA1 polC(dnaE) double mutants incubated at the temperature that blocks DNA replication than inpolA ⁺ polC single mutants. Similarly, thepolA1 mutation sensitizedtif-promoted lysogenic induction in apolA1 tif strain at 42°. In strains bearing thepolA12 mutation, which growth normally at 30°, induction of the prophage occured after the shift to 42°. It is concluded that dissapearance of the DNA polymerase I activity leads to changes in DNA replication that are able, per se, to trigger the prophage induction process.