Cloning and expression of the Escherichia coli replication origin in a single-stranded DNA phage.

The Escherichia coli DNA replication origin (oriC) and the adjacent asparagine synthetase gene (asnA) have been inserted into the duplex replicative form DNA of the single-stranded phage vector M13Goril. By in vitro recombination, the entire oriC asnA-containing plasmid pJS5 was inserted into M13Gori1 in both possible orientations. Both phage types transduce the asnA gene and confer upon the M13 vector the ability to replicate as a plasmid in the E. coli mutant rep3. In rep+ hosts, these phages undergo single-stranded DNA synthesis and viral morphogenesis.