Figure 3.

In vitro transcription experiments on pJCD01 plasmid derivatives in which either the ssrS P1 promoter (ssrS P1 WT) or a mutated derivative (ssrS P1 mut) had been cloned. The ssrS P1 mut carries a double substitution (CG to TA) at positions −3/−2 (shown in the figure). In vitro transcription was performed in the presence of either Eσ^S or Eσ⁷⁰; transcript amounts were determined by quantitative real-time PCR as described in ‘Materials and Methods’ section, using the RNA-I transcript as reference as previously described (22). Experiments were performed three times in duplicate, and standard errors are shown.