FIG. 4.

Transcriptional regulation of yedQ and adrA in strain 1094. (A) yedQ expression was studied in wild-type E. coli 1094 and the 1094rpoS mutant by measuring the β-galactosidase activity of a yedQ::lacZ fusion carried on the pRSpyedQ::lacZ plasmid. The cloning vector pRS415 was used as a negative control in both strains. Light-gray bars, β-galactosidase activity in 1094; dark-gray bars, β-galactosidase activity in 1094rpoS. The error bars represent standard errors of the means. (B) yedQ and adrA expression levels were compared in strain E. coli 1094 by measuring the β-galactosidase activities of a yedQ::lacZ and an adrA::lacZ fusion carried, respectively, on the pRSpyedQ::lacZ and pRSpadrA::lacZ plasmids. The cloning vector pRS415 was used as a negative control. White bars, pRS415 β-galactosidase activity; light-gray bars, pRSpyedQ::lacZ β-galactosidase activity; dark-gray bars, pRSpadrA::lacZ β-galactosidase activity. (C) Sequence alignment of the adrA promoters of E. coli strains 1094 and MG1655. The putative CsgD-binding sequences are shaded, and the −10 box is underlined on the consensus sequence. The sequence differences among E. coli strains are indicated by stars. The ATG start codon is in boldface letters. (D) adrA₁₀₉₄ expression was studied in the wild-type E. coli strains 1094, MG1655, and MG1655ompR234 (PHL818) and their respective csgD mutants by measuring the β-galactosidase activity of an adrA::lacZ fusion carried on the pRSpadrA::lacZ plasmid. The bar shades for β-galactosidase activities in the different strains are as indicated in the graph legend. All the measurements were done at least in triplicate at 37°C in M63B1 medium supplemented with 0.4% glucose (A and B) or at 30°C in LB medium (D).