Strand-specific discontinuity in replicating P2 DNA

Shortly after circularization and covalent closure, infecting bacteriophage P2 DNA becomes attached to a rapidly sedimenting DNA- “membrane” complex ( Ljungquist, 1973 ). In an Escherichia coli rep host, where normal P2 DNA replication is blocked ( Calendar et al. , 1970 ), complex formation occurs, and relaxed circular molecules with short double-stranded tails are produced. The heavy strand of the infecting DNA is preserved as a circle, while the light strand is broken. A functional P2 A gene is required for the production of the strand-specific opening, while the product of the B gene functions in a subsequent step of DNA replication.