title: Regulation of Hfq by the RNA CrcZ in Pseudomonas aeruginosa carbon catabolite repression.
abstract: Carbon Catabolite repression (CCR) allows a fast adaptation of Bacteria to changing nutrient supplies. The Pseudomonas aeruginosa (PAO1) catabolite repression control protein (Crc) was deemed to act as a translational regulator, repressing functions involved in uptake and utilization of carbon sources. However, Crc of PAO1 was recently shown to be devoid of RNA binding activity. In this study the RNA chaperone Hfq was identified as the principle post-transcriptional regulator of CCR in PAO1. Hfq is shown to bind to A-rich sequences within the ribosome binding site of the model mRNA amiE, and to repress translation in vitro and in vivo. We further report that Crc plays an unknown ancillary role, as full-fledged repression of amiE and other CCR-regulated mRNAs in vivo required its presence. Moreover, we show that the regulatory RNA CrcZ, transcription of which is augmented when CCR is alleviated, binds to Hfq with high affinity. This study on CCR in PAO1 revealed a novel concept for Hfq function, wherein the regulatory RNA CrcZ acts as a decoy to abrogate Hfq-mediated translational repression of catabolic genes and thus highlights the central role of RNA based regulation in CCR of PAO1.
authors.affiliation: Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna, Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Sonnleitner
authors.affiliation: Department of Microbiology, Immunobiology and Genetics, Max F. Perutz Laboratories, Center of Molecular Biology, University of Vienna, Vienna, Austria.
authors.forename: Udo
authors.initials: U
authors.lastname: Bläsi
mesh_terms: D000581:Amidohydrolases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D002244:Carbon / Q000378:metabolism; D057465:Catabolite Repression / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D035001:Host Factor 1 Protein / Q000235:genetics*; D011552:Pseudomonas Infections; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism
chemical_list: D035001:Host Factor 1 Protein; D012329:RNA, Bacterial; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D002244:Carbon; D000581:Amidohydrolases