The properties of mutR, a mutator closely linked to thyA, have been further characterized. It was found that the mutator gene is carried on a specialized transducing phage (λpcI857 thyA) generated by the excision of λcI857 integrated at a secondary attachment site between lysA and thyA. Three lines of evidence are presented indicating that mutR is a nonessential gene. Deletions of the mutator can be found among survivors of heat induction of λcI857 when the phage is integrated between lysA and thyA. Mutations in mutR can be induced with the frameshift mutagen ICR 191. An amber mutant in mutR has been found. Viable strains could be made by combining the mutator with polB, polA polB, ligts7, and uvrA mutations. The mutator was still able to increase the spontaneous mutation frequency in these genetic backgrounds. When the reversion patterns of a series of well characterized trpA mutations were analyzed, the results suggested that mutR is more efficient at causing transitions than transversion mutations.
|Original language||English (US)|
|Number of pages||11|
|Journal||Journal of bacteriology|
|State||Published - Dec 1 1975|