Figure 3.

In vitro transcription of plasmid templates containing rrnB P1 promoters with either the wild-type (WT) UP element (lanes 1–3), no UP element (the SUB sequence, see Fig. 2A, lanes 4–6), or the 4192 selected upstream sequence (lanes 7–9). Plasmids were transcribed with WT RNAP (lanes 1, 4, and 7), αΔ235 RNAP (lanes 2, 5, and 8), or αR265A RNAP (lanes 3, 6, and 9). rrnB P1 transcripts (terminated at rrnB T1 ≈220 nt downstream of the transcription start site) and vector-encoded RNA I transcripts (≈110 nt) are indicated with arrows.