Expression of Escherichia coli dnaA and mioC genes as a function of growth rate.

The synthesis of specific cellular components related to the initiation process of DNA replication was correlated with changes in growth rate. The concentrations of DnaA protein and mioC mRNA were determined for cells grown at six different growth rates; both increased relative to either total protein or total RNA, respectively, as the growth rate increased. Expression from the chromosomal mioC promoter, which contains a DnaA protein-binding site, was not repressed when the DnaA protein concentration was increased and was not derepressed in a dnaA46 mutant at 42 degrees C. The mioC transcript had a characteristic mRNA-type half-life of 1.51 min.