A general priming system employing only dnaB protein and primase for DNA replication.

Abstract

Priming of phage .vphi.X174 DNA synthesis is effected simply by dnaB protein and primase when the DNA is not coated by single-strand binding protein (SSB). The 5 prepriming proteins (n, n'', n", i and dnaC protein) required for priming a SSB-coated .vphi.X174 DNA circle are dispensable. The dnaB protein-priming system is also active on uncoated phage G4 and M13 DNA and on poly(dT). Multiple RNA primers, 10-60 nucleotides long, are transcribed with patterns distinctive for each DNA template. Formation of a stable dnaB protein.cntdot.DNA complex in the presence of primase and ATP supports the hypothesis that dnaB protein provides a mobile replication promoter signal for primase.