FIG. 2.

CodY regulates toxin gene expression. Transcription of pagA, lef, and cya in codY wild-type B. anthracis strains and their respective codY disruption mutants was assessed. B. anthracis RBAF140, RBAF143, and RBAF144 (circles) and their codY mutants (squares) were grown in RBic medium under a 5% CO₂ atmosphere. Growth was monitored by A₆₀₀ measurements (open symbols), and transcription of pagA, lef, and cya was determined by measuring β-galactosidase activity (closed symbols). Results shown are representative of three independent experiments. In all three independent experiments, the observed differences were found to be statistically significant, with P values (paired Wilcoxon test) of 0.009, 0.014, and 0.002 for the pagA-lacZ-harboring strains; 0.031, 0.020, and 0.010 for the lef-lacZ-harboring strains; and 0.020, 0.006, and 0.002 for the cya-lacZ-harboring strains.