title: Control of corynebacteriophage reproduction by heteroimmune repression.
abstract: Corynebacteriophages beta and gamma are closely related but heteroimmune; hence, gamma reproduces in C7(beta). A series of gamma mutants, designated gamma-bin (beta-inhibited), has been isolated. They reproduce in only 2 to 14% of infected C7(beta) cells, and, as a result, plaque with an efficiency of 10(-4) to 10(-5) on this strain. The proportion of C7(beta) cells in which gamma-bin phage can replicate is increased to 30 to 80% when immunity is lifted by UV induction of C7(beta) or by heat induction of C7(beta-tsr3). The gamma-bin mutants carry out a normal vegetative or lysogenic cycle in strain C7 and thus do not appear to be defective in any essential phage function. Infection of C7(beta) by gamma-bin results in cell killing whether the infection is productive or nonproductive. The data support the hypothesis that inhibition of gamma-bin is due to the direct or indirect action of a beta prophage gene. The simplest hypothesis is that gamma-bin phages have sustained mutations in an operator site and that beta repressor now combines with the mutated operator to inhibit normal replication in a significant proportion of infected cells.
mesh_terms: D001435:Bacteriophages / Q000235:genetics* / Q000254:growth & development; D003353:Corynebacterium diphtheriae / Q000235:genetics / Q000528:radiation effects; D005809:Genes, Regulator; D005814:Genes, Viral; D006358:Hot Temperature; D008242:Lysogeny; D008769:Methylnitronitrosoguanidine; D009154:Mutation; D014466:Ultraviolet Rays; D014779:Virus Replication
chemical_list: D008769:Methylnitronitrosoguanidine