Cloning of the T7 Genome in Escherichia coli: Use of Recombination between Cloned Sequences and Bacteriophage T7 to Identify Genes Involved in Recombination and a Clone Containing the Origin of T7 DNA Replication

Abstract

We have applied the technique of molecular cloning to the analysis of bacteriophage T7 DNA in order to further refine the physical and genetic maps of T7 as well as to explore its usefulness in describing the biochemical relationships between T7 and its host. Fragments of T7 DNA have been cloned in Escherichia coli using the plasmid pMB9. Such cloned fragments are able to recombine with infecting phages using a T7 recombination system that does not require the products of genes 4, 5, and 6. Since a well-characterized collection of mutants of phage T7 is available, recombination between cloned fragments and infecting mutants provides a means to identify specific T7 DNA sequences in any clone. In addition, recombination provides a means to integrate the physical and genetic maps of T7. Approximately 65% of the T7 DNA has been found in clones so far, and analysis of these clones has mapped...