title: Two small RNAs, CrcY and CrcZ, act in concert to sequester the Crc global regulator in Pseudomonas putida, modulating catabolite repression.
abstract: The Crc protein is a translational repressor that recognizes a specific target at some mRNAs, controlling catabolite repression and co-ordinating carbon metabolism in pseudomonads. In Pseudomonas aeruginosa, the levels of free Crc protein are controlled by CrcZ, a sRNA that sequesters Crc, acting as an antagonist. We show that, in Pseudomonas putida, the levels of free Crc are controlled by CrcZ and by a novel 368 nt sRNA named CrcY. CrcZ and CrcY, which contain six potential targets for Crc, were able to bind Crc specifically in vitro. The levels of CrcZ and CrcY were low under conditions generating a strong catabolite repression, and increased strongly when catabolite repression was absent. Deletion of either crcZ or crcY had no effect on catabolite repression, but the simultaneous absence of both sRNAs led to constitutive catabolite repression that compromised growth on some carbon sources. Overproduction of CrcZ or CrcY significantly reduced repression. We propose that CrcZ and CrcY act in concert, sequestering and modulating the levels of free Crc according to metabolic conditions. The CbrA/CbrB two-component system activated crcZ transcription, but had little effect on crcY. CrcY was detected in P. putida, Pseudomonas fluorescens and Pseudomonas syringae, but not in P. aeruginosa.
authors: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Campus UAM, Cantoblanco, 28049 Madrid, Spain.
authors: Renata
authors: R
authors: Moreno
authors: Pilar
authors: P
authors: Fonseca
authors: Fernando
authors: F
authors: Rojo
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D057465:Catabolite Repression; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009876:Operon; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism*; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D058727:RNA, Small Untranslated / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated; D012097:Repressor Proteins; C101896:crc protein, Pseudomonas