Replication of phiA and phiX174 in Escherichia coli mutants thermosensitive in DNA synthesis.

Thermosensitive mutants of E. coli defective in DNA replication were tested for their capacity to support multiplication of phiA and phiX174. At the restrictive temperature, the viral growth was markedly affected in dnaH, dnaZ, or ligts7 mutants. Even when these strains were transfected with RF1 molecules, the virus yield was still very low. The dnaI function was, however, dispensable for replication of phiA and phiX174. In addition, these viruses could multiply in dnaP or polAts mutants at the high temperature.