Physical and genetic analyses of the Inc-I alpha plasmid R64

Abstract
A 126-kilobase (kb) physical and genetic map of the Inc-I.alpha. plasmid R64 was constructed by using the restriction enzymes, BamHI, SalI, XhoI, HindIII and EcoRI. The replication and incompatability functions of this plasmid were located in a 1.75 kb segment of an EcoRI fragment (3.3 kb). The genes determining growth inhibition of phage BF23, suppression of dnaG (Sog), resistance to tetracycline (Tetr) and resistance to streptomycin (Strr) were located on the 5.5 kb HindIII-XhoI fragment, the 8.1 kb EcoRI fragment, the 4.6 kb HindIII fragment and the 4.1 kb HindIII fragment, respectively. The map of R64 was compared with that of ColIb, which belongs to the Inc-I.alpha. group.