FIG 6.

The L. pneumophila Fis1 and Fis3 proteins bind the regulatory regions of the ceg20, sidC, and legA12 genes. Mobility shift assays were performed with L. pneumophila purified Fis1-His₆ (A and C) and Fis3-His₆ (B and D) proteins and the DIG-labeled probe (1.6 nM) of ceg20 (A), sidC (B), and legA12 (C and D) regulatory regions. The first lane in each panel did not contain any protein. The rest of the lanes contained increasing amounts of the relevant proteins in 2-fold increments, starting from 0.25 μM for Fis1-His₆ and 0.05 μM for Fis3-His₆. Competition was performed by incubating the protein amount indicated with a 100-fold excess of unlabeled probe as a specific competitor (Unlabeled WT) or a probe containing mutations in the Fis sites (Unlabeled Mut.) for 15 min prior to the addition of the DIG-labeled probe. For each of the genes examined, the corresponding mutated probe was used.