Construction of recombinant λ phages that carry the E. coli recB and recC genes

Abstract

A fragment of the E. coli chromosome including the recC gene has been cloned by in vitro recombinant DNA techniques into a phage λ vector to give the recombinant phage λdrecC. This was used to derive the phage λdrecBC by in vivo recombination. On lysogenisation of recB and recC mutants with λdrecBC wild type levels of UV-resistance and RecBC DNase activity were restored. Infection of E. coli with λdrecBC led to the synthesis of phage-coded proteins of 125 kilodaltons (kd) and 135 kd that were not synthesised on infection with the original λ vector, whereas a 125 kd protein but not a 135 kd protein was synthesised in similar experiments with λdrecC. The recombinant phages, which are unable to form plaques, presumably due to the deletion of essential phage genes during their construction, provide useful starting points from which to subclone the recB, recC, and the neighbouring thyA and argA genes individually into multiple copy plasmid vectors.