Directed integration of an F' plasmid by integrative suppression: isolation of plaque forming lambda transducing phage for the dnaC gene.

A new approach for isolation of a plaque forming lambda specialized transducing phage is described. It consists of directed transposition of an F' plasmid into the gal region of a dnaAts galE- Escherichia coli strain by integrative suppression and deletion of the chlD region in order to shorten the distance between the marker of interest on the F' and the prophage serving to prepare an LFT1 lysate. An F' danC+thr+ plasmid was used here and lambdadthr and lambdaddnaC phages were isolated. In addition, lambdapdnaC was obtained from a double lysogen for lambdaddnaC and lambda b2.