title: sigma54-RNA polymerase controls sigma70-dependent transcription from a non-overlapping divergent promoter.
abstract: Divergent transcription of a regulatory gene and a cognate promoter under its control is a common theme in bacterial regulatory circuits. This genetic organization is found for the dmpR gene that encodes the substrate-responsive specific regulator of the sigma(54)-dependent Po promoter, which controls (methyl)phenol catabolism. Here we identify the Pr promoter of dmpR as a sigma(70)-dependent promoter that is regulated by a novel mechanism in which sigma(54)-RNA polymerase occupancy of the non-overlapping sigma(54)-Po promoter stimulates sigma(70)-Pr output. In addition, we show that DmpR stimulates its own production through Po activity both in vivo and in vitro. Hence, the demonstrated regulatory circuit reveals a novel role for sigma(54)-RNA polymerase, namely regulation of a sigma(70)-dependent promoter, and a new mechanism that places a single promoter under dual control of two alternative forms of RNA polymerase. We present a model in which guanosine tetra-phosphate plays a major role in the interplay between sigma(54)- and sigma(70)-dependent transcription to ensure metabolic integration to couple sigma(70)-Pr output to both low-energy conditions and the presence of substrate.
authors.affiliation: Department of Molecular Biology, Umeå University, Umeå, Sweden.
authors.forename: Linda U M
authors.initials: LU
authors.lastname: Johansson
authors.forename: Dafne
authors.initials: D
authors.lastname: Solera
authors.forename: Lisandro M D
authors.initials: LM
authors.lastname: Bernardo
authors.forename: Joana A
authors.initials: JA
authors.lastname: Moscoso
authors.forename: Victoria
authors.initials: V
authors.lastname: Shingler
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D009876:Operon; D011401:Promoter Regions, Genetic; D016958:Pseudomonas putida / Q000235:genetics* / Q000378:metabolism; D051877:RNA Polymerase Sigma 54 / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism*; D020349:Surface Plasmon Resonance; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C080133:DmpR protein, Pseudomonas; D012329:RNA, Bacterial; D012808:Sigma Factor; D015534:Trans-Activators; D006159:Guanosine Tetraphosphate; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54