F-plasmid gene srnB+ complements the function of the S gene of phage lambda

Abstract The srnB ⁺ gene located on the F plasmid was assayed for its capacity to facilitate the release from infected cells of phage λ lacking the usual lytic activity. The srnB ⁺ plasmid pOY54, carrying the 1.4–2.5F fragment in the Eco RI- Bam HI fragment of pBR322, induced bacteriolysis and the release of progeny phage of the λcI 857 susS 7 lysogen in the presence of rifampin at 42°C. An srnB 1 mutant plasmid, pOY541, did not promote bacteriolysis. These results suggest that the srnB ⁺ gene of the F plasmid complements the function of the λ S gene in the nonpermissive host strain.