FIG. 2.
Effect of point substitutions within the hctB promoter on in vitro transcription by C. trachomatis σ28 RNA polymerase. All three possible point substitutions were tested at each position in the −35 element from −37 to −24 (A) and in the −10 element from −17 to −4 (C). The wild-type sequence of the predicted element is shown below each graph. Changes in promoter activity are depicted as the decrease (n-fold) relative to wild-type promoter activity. Decreases greater than 200-fold are not shown as extending below the bottom axis. Each bar represents the mean of three independent experiments. Sample transcription of DNA templates containing the wild-type (wt) hctB promoter and point substitutions of positions −31 (B) and −11 (D) are shown.