Fig 3. Oligomerization of the N-terminal DNA-binding region of VtrA is important for the transcriptional regulatory activity of VtrA.
(A) β-galactosidase activity from PvtrB-lacZ transcriptional reporter of E. coli MC4100 upon expression of VtrAN and its ZIP-fusions. The values represent the mean ± SD for a minimum of three independent experiments. *, p < 0.01; NS, not significant, compared with VtrAN by one-way ANOVA followed by Dunnett’s multiple comparison test. (B) Electrophoretic mobility shift assays using VtrAN and its ZIP fusions. Increased concentrations (0, 16, 40, 80, 160 and 400 nM) of each protein were incubated with 4 nM biotinylated DNA probe corresponding to 284-bp upstream region of vtrB, and then subjected to native PAGE. The biotinylated probe was transferred to a nylon membrane, UV cross-linked, and detected using HRP-conjugated streptavidin.