title: Induction of prophage lambda in Escherichia coli recA- strain by N-methyl-N'-nitro-N-nitrosoguanidine.
abstract: Induction of prophage by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) occurred in a recA- strain lysogenic for lambda phage at a level significantly higher than the spontaneous level although the frequency was much lower than that of induction in a recA+(lambda) strain. The plaque-forming ability of lambda c17 super-infecting the recA-(lambda) strain pretreated with MNNG increased with dose of MNNG as it did for super-infection of the recA+(lambda) strain, indicating that the frequency of maturation of lambda c17 increased owing to a decrease in the immunity of the lambda lysogen with dose of MNNG given to it. Further, the activity of lambda repressor in the recA-(lambda) strain decreased after treatment with MNNG as measured by the decrease of repressor-binding activity to lambda DNA although it decreased at a 3-fold slower rate than that in recA+(lambda) strain. From these results and others previously reported we conclude that inactivation of repressor leading to MNNG-initiated prophage induction takes place through two pathways, one being the recA-dependent normal process and the other a recA-independent process unique to the effect of MNNG.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D010582:Bacteriophage lambda / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D008242:Lysogeny; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D009154:Mutation; D011938:Rec A Recombinases; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D008769:Methylnitronitrosoguanidine; D011938:Rec A Recombinases