Incorporation of thymine into φe dna during transfection of Bacillus subtilis

Abstract

Phage φe, whose DNA contains hydroxymethyl uracil in place of thymine, excludes thymine from its DNA by inducing enzymes that degrade TTP and block thymidylate synthetase. During transfection of Bacillus subtilis with φe DNA, however, progeny phage can be labeled with [ 3H]thymine at an average of 1000 thymine residues per phage, a level eightfold higher than that found after normal phage infection. This observation supports a transfection model in which bacterial polymerases, using thymine, repair gaps in phage DNA molecules created by the renaturation of single-strand fragments of phage DNA taken up by competent cells.