Proc Natl Acad Sci U S A 69: 2691-5 (1972)
Conversion of single-stranded DNA of phage PhiX174 to the
double-stranded replicative form in Escherichia coli uses enzymes
essential for initiation and replication of the host chromosome.
These enzymes can now be purified by the assay that this phage system
provides. The PhiX174 conversion is distinct from that of M13. The
reaction requires different host enzymes and is resistant to
rifampicin and streptolydigin, inhibitors of RNA polymerase. However,
RNA synthesis is essential for PhiX174 DNA synthesis: the reaction is
inhibited by low concentrations of actinomycin D, all four
ribonucleoside triphosphates arc required, and an average of one
phosphodiester bond links DNA to RNA in the isolated double-stranded
circles. Thus, we presume that, as in the ease of M13, synthesis of a
short RNA chain primes the synthesis of a replicative form by DNA
polymerase. Initiation of DNA synthesis by RNA priming is a mechanism
of wide significance.