Fig. 8.

In vitro transcription from the region of the pcnB gene (a) and mapping of the pS2 transcription start sites (b). In experiments shown in a, E. coli RNA polymerase holoenzymes bearing different σ factors (marked above particular lanes) were used in the reactions performed as described in “Materials and methods”. Positions of transcripts derived from pB, pS1 and pS2 promoters are indicated. In the control experiment, activities of all holoenzymes were demonstrated by employing DNA templates containing promoters specific for various σ factors (templates with the rpoH gene promoter region and the dnaK gene promoter region, described by Janaszak et al. 2007, were used); positions of bands corresponding for transcripts originating from particular promoters are indicated. In experiments shown in b, primer extension experiments with primer PS2.rev were performed using the products of in vitro transcription reactions as templates. In c, proposed localization of pS1 and pS2 promoters in the region upstream of the coding sequence of the pcnB gene is shown