The Role of Escherichia coli dnaG Function in Coliphage M 13 DNA Synthesis

Abstract

Examination of the role of E. coli dnaG function in different stages of M13 phage DNA synthesis by ultracentrifugal analysis of intracellular phage DNA in a thermosensitive dnaG mutant shows that: the formation of parental double-strand replicative-form DNA (rfDNA) from the infecting virus is independent of dnaG function; the synthesis of progeny rfDNA requires dnaG product; after a pool of rfDNA is made up, dnaG function is not required for the progeny single-strand DNA (ssDNA) synthesis. The ssDNAs produced under nonpermissive condition are mostly circular and biologically functional.