Fig. 1
c-di-GMP inhibits gbpA expression independently of the Vc1 riboswitch. a GbpA production by V. cholerae wild type and ∆Vc1 strains, each with vector (pBAD33) or pPDE, was determined by western blot. PDE gene expression was induced as described in the Methods. The image shown is a representative of three independent experiments. Densitometry analyses were done by normalizing the intensities of the bands corresponding to GbpA to the intensities of a cross-reactive band in the same lane (indicated by an asterisk), then comparing the normalized value to that of wild type V. cholerae with vector only. The fold change relative to wild type is indicated below each lane. b qRT-PCR was used to measure gbpA transcript levels in the strains described in (A), in V. cholerae with vector (black bars) or with pPDE (grey bars). The data were normalized relative to the wild-type containing vector only, using rpoB as the reference gene. c P gbpA -Vc1-lacZ or P gbpA -∆Vc1-lacZ fusions were each introduced into V. cholerae with vector (black bars) or pPDE (grey bars), and the β-galactosidase activity in culture lysates of these strains was measured. d qRT-PCR was used to measure gbpA transcript levels in V. cholerae with vector, pPDE, pPDEmut or pVC1592. The data were normalized relative to the wild-type containing vector, using rpoB as the reference gene. b-d Shown are the mean values and standard deviations of at least three independent experiments. ***P < 0.001 by unpaired t-test comparing the indicated sets of data