Figure 1.

Riboswitch-mediated attenuation and cyclic di-AMP abundance in S. coelicolor throughout development. (A) Wild-type S. coelicolor, constitutively expressing the rpfA riboswitch transcriptionally fused to the luciferase reporter gene cluster (M145/pMC222), was grown on a sporulation-conducive solid medium. Reporter activity was quantified throughout growth and development. Background-subtracted luminescence was normalized to that of the positive control strain constitutively expressing the reporter without the rpfA riboswitch (M145/pFLUX-Pos). Normalized reporter activity was expressed as mean fold changes ± standard deviation (n = 3) relative to ‘20 h’. Figure is representative of 8 independent experimental replicates. (B) Wild-type S. coelicolor (M145) was grown at 30°C on a sporulation-conducive solid medium. At the indicated times, cyclic di-AMP was extracted from cells and quantified by LC-MS/MS. Cyclic di-AMP levels were normalized to wet cell weight. Data are presented as mean ± standard error (n = 4).