Site-specific integration of an F' lac pro factor in the region of the replication origin (oriC) of E. coli.

An episome, F128, which carries approximately 8 x 10(4) base pairs of chromosomal DNA homologous to the lac pro region of the E. coli chromosome, has been found to integrate into the oriC region of the chromosome in a site specific reaction. While the event appears to be recA-dependent, no homology between the episome and this region of the chromosome was detected. The Hfr strains formed result from the integration of intact F128 molecules. The structure of the Hfr strains generated has been determined and their transfer properties analyzed.