FIG. 5.

Primer extension analyses for the determination of the transcriptional start site of the csgDEFG operon. RNA was prepared from strains UMR1 and MAE40 (the rpoS derivative of ATCC 14028-1s) grown at 28°C on plates, and primer extension was carried out as described in Materials and Methods. An extension product is seen for UMR1 but not for MAE40. Primer PEXD1, located 58 bp downstream of the csgDEFG start codon, was used for the extension reaction as well as for the sequencing reaction on pUMR10-7 as a template. The sequence derived from the PEXD1 primer on pUMR10-7 is complementary to the RNA template, so the coding strand is automatically shown. The transcriptional start site (asterisk) and bases belonging to the putative promoter sequences (boxed) are indicated.