In vitro DNA replication of recombinant plasmid DNAs containing the origin of progeny replicative form DNA synthesis of phage phi X174.

Abstract
The origin of phage .vphi.X174 progeny replicative form (RF) DNA synthesis was inserted into the plasmid vector pBR322 and cloned. In direct contrast to pBR322, the recombinant superhelical plasmids can substitute for .vphi.X174 RFI DNA as template in .vphi.X174-specific reactions in vitro. The recombinant plasmids are cleaved by the .vphi.X174 A protein, support net synthesis of unit-length single-stranded circular DNA in the presence of the .vphi.X174 A protein and Escherichia coli rep protein, DNA-binding protein, and DNA polymerase III elongation system, and support replication of duplexes catalyzed by the .vphi.X174 A protein and crude extracts of E. coli.