FIG. 4.

In vitro transcription with the 5′ upstream region of prfA containing the two previously mapped promoters PprfA1 (P1) and PprfA2 (P2) (8). (A) Wild-type PrfA and hyperactive PrfA* (24, 27) proteins and RNAP loaded with different amounts of purified SigB protein were used as indicated. (B) The primer extensions were carried out to determine the transcriptional start sites. (C) The putative −35 and −10 boxes of SigB- and SigA-recognized promoters and the transcription start sites (rt1, rt2, and rt3) are indicated.