FIG. 2.

Overexpression of fimYZ activates hilE-lacZY expression in E. coli. Strains were grown with shaking in Lennox broth to the late stationary phase. Each strain carried plasmid pMAB69, which is a low-copy-number hilE reporter carried on the pRW50 vector. Plasmid pISF182 has the fimYZ genes cloned into pACYC184 and expressed from the tetracycline promoter. Plasmids pISF187 (fimZ⁺ fimY) and pISF189 (fimZ fimY⁺) are identical to pISF182 except for the insertion of a transcriptional terminator (see Materials and Methods). E. coli carrying only pISF187 or only pISF189 was not induced for hilE-lacZY expression, indicating that both fimY and fimZ are necessary for the expression of hilE. Expression levels were determined by measuring β-galactosidase activity. Experiments were performed at least three times.