Initiation of DNA replication in Escherichia coli after overproduction of the DnaA protein - PubMed (original) (raw)

Initiation of DNA replication in Escherichia coli after overproduction of the DnaA protein

K Skarstad et al. Mol Gen Genet. 1989 Jul.

Abstract

Flow cytometry was used to study initiation of DNA replication in Escherichia coli K12 after induced expression of a plasmid-borne dnaA+ gene. When the dnaA gene was induced from either the plac or the lambda pL promoter initiation was stimulated, as evidenced by an increase in the number of origins and in DNA content per mass unit. During prolonged growth under inducing conditions the origin and DNA content per mass unit were stabilized at levels significantly higher than those found before induction or in similarly treated control cells. The largest increase was observed when using the stronger promoter lambda pL compared to plac. Synchrony of initiation was reasonably well maintained with elevated DnaA protein concentrations, indicating that simultaneous initiation of all origins was still preferred under these conditions. A reduced rate of replication fork movement was found in the presence of rifampin when the DnaA protein was overproduced. We conclude that increased synthesis levels or increased concentrations of the DnaA protein stimulate initiation of DNA replication. The data suggest that the DnaA protein may be the limiting factor for initiation under normal physiological conditions.

PubMed Disclaimer

Similar articles

Cited by

References

    1. EMBO J. 1986 Nov;5(11):2987-94 - PubMed
    1. Mol Gen Genet. 1979 Sep;175(2):135-44 - PubMed
    1. J Bacteriol. 1988 Feb;170(2):852-8 - PubMed
    1. Proc Natl Acad Sci U S A. 1983 Oct;80(19):5817-21 - PubMed
    1. Mol Gen Genet. 1985;200(3):442-50 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources