FIG. 6.
Mapping and regulation of the pilE, sia, and pilC1 promoters. Primer extension analyses were performed with the same RNA used for the experiment shown in Fig. 5 and with primers pilE-PE1 (A), sia-PE1 (B), and pilC-PE2 (C) to assess regulation of the PpilC1, PpilE, and Psia promoters, respectively. Sequencing reactions carried out with each cloned promoter fragment served as size markers (lanes G, A, T, and C). Independent of the strain and of MBL treatment, major bands show no appreciable variation in the amount of elongated products. Analyses of the DNA sequence upstream of the identified major bands revealed the presence of −10 and −35 regions similar to the E. coli sigma 70 consensus sequences, −10-TATAAT and −35-TTGACA. While no promoter consensus sequences were identified upstream of the other 5′ ends of RNA mapping downstream of the PpilE and PpilC1 promoters, a putative promoter sequence, AATAAA-N17-TATAAT, was detected upstream of the 5′ end of RNA mapping 48 nucleotides upstream of the sia genes (faster-migrating band in panel B).