title: The GntR-like regulator TauR activates expression of taurine utilization genes in Rhodobacter capsulatus.
abstract: Rhodobacter capsulatus can efficiently grow with taurine as the sole sulfur source. The products of the tpa-tauR-xsc gene region are essential for this activity. TauR, a MocR-like member of the GntR superfamily of transcriptional regulators, activates tpa transcription, as shown by analysis of wild-type and tauR mutant strains carrying a tpa-lacZ reporter fusion. Activation of the tpa promoter requires taurine but is not inhibited by sulfate, which is the preferred sulfur source. TauR directly binds to the tpa promoter, as demonstrated by DNA mobility shift assays. As expected for a transcriptional activator, the TauR binding site is located upstream of the transcription start site, which has been determined by primer extension. Site-directed promoter mutations reveal that TauR binds to direct repeats, an unusual property that has to date been shown for only one other member of the MocR subfamily, namely, GabR from Bacillus subtilis. In contrast, all other members of the GntR family analyzed so far bind to inverted repeats.
authors.affiliation: Lehrstuhl für Biologie der Mikroorganismen, Fakultät für Biologie, Ruhr-Universität Bochum, 44780 Bochum, Germany. bernd.masepohl@rub.de
authors.forename: Jessica
authors.initials: J
authors.lastname: Wiethaus
authors.forename: Britta
authors.initials: B
authors.lastname: Schubert
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Pfänder
authors.forename: Franz
authors.initials: F
authors.lastname: Narberhaus
authors.forename: Bernd
authors.initials: B
authors.lastname: Masepohl
mesh_terms: D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000096:biosynthesis*; D001665:Binding Sites; D004269:DNA, Bacterial / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D017930:Genes, Reporter; D026901:Membrane Transport Proteins / Q000096:biosynthesis*; D016297:Mutagenesis, Site-Directed; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D016354:Rhodobacter capsulatus / Q000502:physiology*; D013654:Taurine / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D000637:Transaminases / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; D015534:Trans-Activators; D013654:Taurine; D000637:Transaminases; C022715:taurine pyruvate aminotransferase