title: Cloning of the immunity repressor determinant of bacteriophage P2 in the pBR322 plasmid.
abstract: Through in vitro recombination of DNA restriction fragments, we have constructed a plasmid, which expressed in vivo the immunity repressor gene (C) of bacteriophage P2. A bacterial strain carrying such a plasmid showed a high level of P2 specific immunity. It was lysogenized normally by an infecting P2, but the frequency of spontaneous phage production was reduced about 10(4) fold as compared to a normal P2 lysogen. Satellite phage P4, known to derepress P2 lysogens, was unable to derepress the plasmid-carrying lysogenic strain so to allow growth of coinfecting P2. Phage P4 multiplied on the plasmid-carrying, P2-lysogenic strain, but due to a prolonged latent period failed to form plaques on this strain.
mesh_terms: D003001:Cloning, Molecular; D003090:Coliphages / Q000235:genetics* / Q000254:growth & development; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004279:DNA, Viral; D004926:Escherichia coli / Q000235:genetics; D005814:Genes, Viral; D005822:Genetic Vectors; D008242:Lysogeny; D010957:Plasmids; D014775:Virus Activation
chemical_list: D004279:DNA, Viral; D004262:DNA Restriction Enzymes