Mutations in bacteriophage lambda that alter phage dependence on the htpR gene product of Escherichia coli.

Six mutants of lambda having reduced dependence on the htpR function of Escherichia coli were isolated from lambda cIts857. Burst sizes in htpRts cells at 40.5 degrees were in the range of 10 to 20 particles per cell. Mapping and complementation analysis of one of the mutants suggested that the mutation in this isolate is in gene J. Additional evidence that the mutations in most of the isolates are in J was provided by the finding that all but one of the mutants differ from the parental phage in properties pertaining to extended host range.