title: Transcriptional activation of the CrcZ and CrcY regulatory RNAs by the CbrB response regulator in Pseudomonas putida.
abstract: The CbrAB two-component system has been described as a high-ranked element in the regulatory hierarchy of Pseudomonas putida that controls a variety of metabolic and behavioural traits required for adaptation to changing environmental conditions. We show that the response regulatory protein CbrB, an activator of σ(N) -dependent promoters, directly controls the expression of the small RNAs CrcZ and CrcY in P. putida. These two RNAs sequester the protein Crc, which is a translational repressor of multiple pathways linked to carbon catabolite repression. We characterized the in vivo and in vitro activation by CbrB at both crcZ and crcY promoters, and identified new DNA sequences where the protein binds. IHF, a co-activator at many σ(N) -dependent promoters, also binds to the promoter regions and contributes to the activation of the sRNAs. CbrB phosphorylation is necessary at physiological activation conditions, but a higher dose of the protein allows in vitro transcriptional activation in its non-phosphorylated form. We also show there is some production of CrcY coming from an upstream promoter independent of CbrB. Thus, CbrAB constitute a global signal transduction pathway integrated in a higher regulatory network that also controls catabolite repression through the expression of the two regulatory RNAs CrcZ and CrcY.
authors.affiliation: Centro Andaluz de Biología del Desarrollo, CSIC, Universidad Pablo de Olavide, Carretera de Utrera, Km. 1, 41013, Seville, Spain.
authors.forename: Sofía Muñoz
authors.initials: SM
authors.lastname: García-Mauriño
authors.forename: Isabel
authors.initials: I
authors.lastname: Pérez-Martínez
authors.forename: Cristina I
authors.initials: CI
authors.lastname: Amador
authors.forename: Inés
authors.initials: I
authors.lastname: Canosa
authors.forename: Eduardo
authors.initials: E
authors.lastname: Santero
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D001665:Binding Sites; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D016958:Pseudomonas putida / Q000235:genetics*; D022661:RNA, Untranslated / Q000096:biosynthesis*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D022661:RNA, Untranslated; D014157:Transcription Factors