[Dependence of recA gene for the replication of chromosome of Escherichia coli initiated by the integrated mini-F plasmid carrying IS1 sequence].

We have reported the dependence of recA gene for the replication of chromosome of E. coli initiated by the F' plasmid but not the F plasmid. Mini-F plasmids with ISI sequence and origin of replication from F and F' plasmid have been constructed. 20% of the integrative suppression strains of these mini-F plasmids were found to be recA dependent, irrespective of the origin of replication (F or F' plasmid) and the direction of replication (uni- or bidirectional). The reported experimental results tend to suggest that the site of integration is of primary importance in the dependence vs independence of recA gene for the replication of the chromosome initiated by the integrated plasmid.