Inhibition of bacteriophage M13 and phiX174 duplex DNA replication and single strand synthesis in temperature sensitive dnaZ mutants of Escherichia coli

A functional dnaZ product, known to be essential for host DNA polymerization and for the synthesis of M13 and phiX174 parental replicative-form (RF) DNA, is required also for RF replication and single-strand synthesis by both of these phages. All three stages of M13 and phiX174 DNA replication (parental RF formation, RF replication, and single-strand synthesis) are inhibited in dnaZts mutants at elevated temperatures. In addition, the thermolabile step in M13 parental RF formation appears to occur after RNA priming; i.e., the synthesis of M13 RF DNA proceeded when a dnaZts mutant, infected at a nonpermissive temperature, was transferred to a permissive temperature in the presence of rifampin.