Figure 5
LeuO regulates the transcription of its own coding gene. (a) β-Galactosidase activity of a leuO-lacZ fusion in the absence (open bars) and presence (solid bars) of exogenous 5 mM cFP in wild type V. vulnificus, a leuO-deletion isotype, and the deletion mutant with leuO in trans (pBBR12-leuO). The error bars denote standard deviations of three independent experiments (**P < 0.005). (b) Transcription levels of leuO as measured by β-Galactosidase activities from ∆leuO (pBBR12-leuO-ara) harboring pMZtc-leuO (upper panel), and translation levels as determined by western hybridization using an antibody against LeuO (lower panel). Culture conditions are described in Materials and Methods. To induce the expression of LeuO, the culture was split into six aliquots after reaching an A600 of 0.4, and then arabinose was added to each at concentrations ranging from 0–0.1%. Error bars denote standard deviations of three independent experiments.
