FIGURE 5.

Gene expression mediated by an azaaromatic riboswitch. (A) Plots of β-galactosidase reporter gene expression data in WT B. subtilis cells carrying the yjdF RNA motif and flanking sequenced fused to the lacZ gene as depicted in Figure 4A. Cells carry either the WT yjdF motif RNA, or one of the mutations M1, M2, or M3 as depicted in Figure 1B. Cells are grown in the presence of proflavine (left) or chelerythrine (right). (Inset) Cells carrying riboswitch–reporter fusion constructs created by using the fluoride-responsive crcB riboswitch from B. subtilis, or the ykkC orphan riboswitch also from B. subtilis, were exposed to proflavine as a control. (B) Agar-diffusion assays using cells carrying the various reporter-fusion constructs as denoted and exposed to proflavine.