FIG. 6.

Region 4.2 of σ⁷⁰ is not required for ExsA-independent transcription of the P_exsC promoter. (A) Diagram of transcription templates used in this experiment. The −35 regions (underlined), extended −10 elements (boxed), −10 elements (boxed), and point mutations (bold) are indicated. (B) Single-round in vitro transcription assays were performed with σ⁷⁰ and σ^70Δ4.2 reconstituted RNAP holoenzymes normalized for specific activity using the P_RE# extended −10 promoter (lanes 3 and 4). Reactions were performed as described in the legend to Fig. 3, and open complexes were allowed to form for 1 min (lanes 1 to 4, 9, and 10) or 20 min (lanes 5 to 8) as indicated.