Isolation and characterization of a lambdapolA transducing phage.

Publisher Website
Google Scholar
Abstract
A plaque-forming .lambda.polA phage was isolated from a population of transducing phage made in vitro from Escherichia coli DNA and a phage vector digested with restriction endonuclease HindIII. Amber mutations, in genes whose products are necessary for late protein synthesis (Q) and cell lysis (S), were crossed into the .lambda.polA phage. Infection of polA+ or polA- bacteria with this phage, under conditions permitting DNA replication but preventing phage production and lysis, elevated the levels of DNA polymerase I to between 75- and 100-fold that detected in a wild-type strain. The kinetics of enzyme production suggest that the polA gene is transcribed from its own promoter rather than from any of the well-characterized phage promoters. The fragment of E. coli DNA within the .lambda.polA phage comprises .apprx. 5000 base pairs, sufficient to accommodate the polA gene and 1, or 2, coding sequences for smaller proteins.