Cellular Levels and Binding of c-di-GMP Control Subcellular Localization and Activity of the Vibrio cholerae Transcriptional Regulator VpsT
Figure 3
The Subcellular Localization of VpsT is Dependent on c-di-GMP Binding and DNA Binding Residues.
(A) The expression of a chromosomal vpsL promoter-lacZ fusion was measured in wild type (Wt) or ΔvpsT strains containing pBAD vector alone, or pBAD containing gfp fused to wild type and mutated versions of vpsT using β-galactosidase assays. A R134A mutation disrupts c-di-GMP binding and an I141E mutation abolishes c-di-GMP-dependent dimerization. H193A lies in the DNA binding domain of VpsT. (B) Subcellular localization of GFP, GFP-VpsT or GFP-VpsT containing the indicated point mutations, expressed in V. cholerae ΔvpsT. Representative epifluorescence micrographs are shown. Marker is 2 µm. (C) Single-cell quantification of subcellular fluorescence localization. The number of spots per cell is shown as a histogram for ΔvpsT strains expressing GFP, GFP-VpsT or GFP-VpsT containing the indicated point mutations. Data are acquired from at least 3 independent experiments and quantification was performed on at least 150 cells per treatment.