THE ABORTIVE REPLICATION OF ΦX174 DNA IN A RECOMBINATION-DEFICIENT MUTANT OF Escherichia coli

Abstract

An E. coli mutant, (REP") that can adsorb but not replicate [PHI]X was isolated. The single-stranded viral DNA is incorporated as the double-stranded replicative form (RF) which is biologically active; however, this "parental" RF does not replicate, and the vital infection aborts. The REP-lac-Smr females mated with Hfr H lac+Sm8 males yield 30-fold fewer lac+Smr recombinants than REP+, although REP" can accept and propagate F factors and zygotically induce [lambda] prophages. The mutant has a 1 -hit UV inactivation curve with the same slope as the limiting slope of the multihit inactivation curve of REP+. The REP- appears to have certain characteristics in common with thy mine-starved REP+. This mutant represents a new class of recombination-deficient bacteria.