Recombination of bacteriophage phi X174 by the red function of bacteriophage lambda

Recombination of bacteriophage phi X174 was effectively promoted when the Red function of lambda was supplied by either co-infection with lambda or induction of lambda lysogens. Mutations in red alpha and red beta genes of lambda abolished recombination nearly completely, whereas a mutation in gam gene reduced it only slightly. The Red-promoted recombination of phi X174 occurred in recA, recB, and polA mutants as well as in wild-type strains of Escherichia coli. It was further stimulated when phi X174 mutants were irradiated with UV light before infection.