FIG. 3.

Radiometric in vitro transcription. (A) A phosphorimage of [³²P]CTP-labeled SigA and SigF transcripts formed in the absence and presence of rifampin (1.25 to 320 nM). In vitro transcription was performed using 10 nM core RNAP combined with 100 nM rSigA or rSigF on a PCR-amplified Phsp60 (20 nM) or PrsbW (20 nM) template, respectively. (B) Rifampin-mediated decrease in transcript intensity as quantified by densitometry of the phosphorimage.