Fig. 7.

CsgD-binding activity of three CsgD boxes on the csgB promoter. Three sets of csgB promoter probes were constructed and examined for CsgD-binding activity by gel shift assay. (A) 5′ deletion set of the csgB promoter; (B) internal segments, each carrying one of three CsgD boxes; (C) 3′ deletion set of the csgB promoter. Construction of 5′ deletion (A) and 3′ deletion (C) probes was carried out by PCR using the primer pairs described in Materials and Methods, while the internal segment probes (B) were prepared by hybridization of complementary single-stranded DNA segments (see Table S1 for sequences).