FIG 3.

CpxR regulates expression of rprA in EPEC. (A) Luminescence assays comparing rprA-lux reporter expression in wild-type EPEC carrying vector control pCA24N or the overexpression plasmid pCA-nlpE. (B) Luminescence assays comparing rprA-lux reporter expression in wild-type EPEC and cpxA24 (Cpx-activating mutation) and cpxR (Cpx-inactivating mutation) strains of EPEC. Luminescence was normalized to the OD₆₀₀ of the culture. Data for luminescence assays represent the means and standard deviations of five replicate cultures. Asterisks denote a statistically significant difference from the relevant wild-type or vector control (P < 0.05, one-way ANOVA with Bonferroni's multiple-comparison test). (C) EMSA. A PCR product containing the rprA promoter region was incubated alone or with increasing concentrations of MBP-CpxR∼P protein and then subjected to 5% native polyacrylamide electrophoresis. DNA was detected with ethidium bromide staining.