Summary
We have constructed a pBR322 plasmid derivative which expresses dnaA protein under the control of the E. coli lac UV5 promotor. Expression of the dnaA protein from the plasmid is inducible by isopropyl-β-D-thiogalactoside. In a dnaA + strain induction has no effect on the accumulation of DNA. In contrast, in a thermosensitive dnaA46 strain, induction, at either the permissive or the nonpermissive temperature, results in an immediate stimulation of DNA accumulation. We conclude that, while in a dnaA46 strain dnaA protein limits DNA replication, in a dnaA + strain dnaA protein activity does not control the timing of replication initiation.
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Communicated by W. Arber
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Churchward, G., Holmans, P. & Bremer, H. Increased expression of the dnaA gene has no effect on DNA replication in a dnaA + strain of Escherichia coli . Mol Gen Genet 192, 506–508 (1983). https://doi.org/10.1007/BF00392197
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DOI: https://doi.org/10.1007/BF00392197