Function of cloned T4 recombination genes, uvsX and uvsY, in cells of Escherichia coli

Summary Genes uvsX and uvsY of bacteriophage T4 both control genetic recombination and repair of damaged DNA, and their mutant phenotypes bear a striking resemblance to each other. It has been shown recently that the uvsX gene product is analogous to the recA gene product of Escherichia coli (Yonesaki et al. 1985; Yonesaki and Minagawa 1985; Formosa and Alberts 1986), but the function of the uvsY gene is unknown. To obtain further insight into the function of these genes we introduced plasmid-borne copies of the two genes separately or together into E. coli. The uvsX gene rendered recA ^- cells more resistant to UV and raised the recombination frequency of phage and E. coli, but hampered induction of the prophage and the SOS function of E. coli. The uvsY gene had no detectable function when introduced alone into E. coli but significantly enhanced the function of the uvsX gene when the two plasmid-borne genes were introduced together.