title: Cross-regulation by CrcZ RNA controls anoxic biofilm formation in Pseudomonas aeruginosa.
abstract: Pseudomonas aeruginosa (PA) can thrive in anaerobic biofilms in the lungs of cystic fibrosis (CF) patients. Here, we show that CrcZ is the most abundant PA14 RNA bound to the global regulator Hfq in anoxic biofilms grown in cystic fibrosis sputum medium. Hfq was crucial for anoxic biofilm formation. This observation complied with an RNAseq based transcriptome analysis and follow up studies that implicated Hfq in regulation of a central step preceding denitrification. CrcZ is known to act as a decoy that sequesters Hfq during relief of carbon catabolite repression, which in turn alleviates Hfq-mediated translational repression of catabolic genes. We therefore inferred that CrcZ indirectly impacts on biofilm formation by competing for Hfq. This hypothesis was supported by the findings that over-production of CrcZ mirrored the biofilm phenotype of the hfq deletion mutant, and that deletion of the crcZ gene augmented biofilm formation. To our knowledge, this is the first example where competition for Hfq by CrcZ cross-regulates an Hfq-dependent physiological process unrelated to carbon metabolism.
authors.affiliation: Department of Microbiology, Immunobiology and Genetics, Center of Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Petra
authors.initials: P
authors.lastname: Pusic
authors.affiliation: Department of Microbiology, Immunobiology and Genetics, Center of Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Muralidhar
authors.initials: M
authors.lastname: Tata
authors.affiliation: Institute of Theoretical Chemistry, University of Vienna, Währingerstrasse 17, 1090 Vienna, Austria.|Center for Anatomy and Cell Biology, Medical University of Vienna, Währingerstrasse 13, 1090 Vienna, Austria.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Wolfinger
authors.affiliation: Department of Microbiology, Immunobiology and Genetics, Center of Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Sonnleitner
authors.affiliation: Helmholtz Center for Infection Research, Molecular Bacteriology, Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Häussler
authors.affiliation: Department of Microbiology, Immunobiology and Genetics, Center of Molecular Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter, Dr. Bohr-Gasse 9, 1030 Vienna, Austria.
authors.forename: Udo
authors.initials: U
authors.lastname: Bläsi
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms; D002244:Carbon / Q000737:chemistry; D057465:Catabolite Repression; D004305:Dose-Response Relationship, Drug; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D009243:NAD; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D014176:Protein Biosynthesis; D011550:Pseudomonas aeruginosa / Q000235:genetics*; D012313:RNA / Q000032:analysis*; D012329:RNA, Bacterial / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D017423:Sequence Analysis, RNA; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D009243:NAD; D012313:RNA; D002244:Carbon; D010100:Oxygen