Role of bacteriophage M13 gene 2 in viral DNA replication

Abstract

The gene 2 protein of the filamentous single-stranded DNA phage M13 is shown to be essential for single-stranded DNA synthesis as well as for synthesis of the double-stranded replicative form (RF) DNA. The results from temperature-shift experiments with gene 2 temperature-sensitive mutants and from infections with gene 2 amber mutants lead us to conclude that the gene 2 protein is involved in introducing a single-strand break into the covalently closed circular RFI † † Abbreviations used: RF, circular double-stranded replicative form DNA; RFI, RF DNA in which both strands are covalently closed circles; RFII, RF DNA containing one or more single-strand breaks; SS, single-stranded DNA; am, amber and ts, temperature-sensitive conditional lethal mutants; su +, suppressing and su −, non-suppressing host cells for am mutations. molecules, thus allowing them to replicate.