Structural and Functional Analysis of Toxin and Small RNA Gene Promoter Regions in Bacillus anthracis.

It was previously demonstrated that anthrax toxin activator (AtxA) binds directly to the σ-like promoter region of (encoding protective antigen, PA) immediately upstream of the RNA polymerase binding site. In this study, using electrophoretic mobility shift assays and analyses, we identified AtxA-binding sites in the promoter regions of the and genes (encoding lethal and edema factors, respectively) and of two Bacillus anthracis small RNAs (XrrA and XrrB). Activities of all four newly studied promoters were enhanced in the presence of CO/bicarbonate and AtxA, as previously seen for the promoter.