Fig 3.

Activity of the PospZ-lacZ fusions in wild-type Shigella and a virB mutant. (A) β-Galactosidase activity resulting from cells carrying either the wild-type full-length promoter (pospZ-5′t(−1613), the full-length promoter containing mutated VirB binding sites (pDB15), or a promoterless control (pMAP07) grown at 37°C. Assays were run in triplicate, and the means and standard deviations are shown.*, P < 0.01. (B) Fold increase in ospZ promoter activity in cells grown with (pBAD-virB) or without (pBAD18) induction of virB. In each case, β-galactosidase activity from the promoterless control in each strain background was subtracted from those generated by cells carrying PospZ-lacZ fusions. The resulting data were normalized to activities obtained in the virB mutant strain carrying pDB15 (construct with the mutated VirB binding sites) when these cells were grown at either 30 or 37°C. Assays were run in triplicate, and the means and standard deviations are shown.