ROLE OF ERF RECOMBINASE IN P22-MEDIATED PLASMID TRANSDUCTION

In the absence of host RecA function, plasmid transduction by bacterio phage P22 can be mediated by Erf recombinase. Erf is not carried on th e infecting particle but synthesized upon infection. In the recipient cell, Erf can promote both generalized plasmid transduction (which req uires the circularization of plasmids transduced as linear multimers) and specialized plasmid transduction (which requires the release of pl asmid DNA from linear plasmid-phage cointegrates). Both processes of E rf-mediated plasmid transduction require host RecBCD function. In cont rast, RecBCD is not required for Erf-mediated circularization of P22 D NA.