title: Transcriptional regulation of nitrate assimilation in Pseudomonas aeruginosa occurs via transcriptional antitermination within the nirBD-PA1779-cobA operon.
abstract: Bioinformatic approaches employed to analyse intergenic regions of Pseudomonas aeruginosa O1 (PAO1) for small RNAs (sRNAs) revealed a putative RNA gene encoded upstream of the nitrate assimilation operon nirBD-PA1779-cobA. Here, we show that this RNA, termed nitrogen assimilation leader A (NalA), represents the leader RNA of the nirBD-PA1779-cobA operon, and that nalA transcription is σ(54)- and NtrC-dependent. A PAO1 nalA deletion strain and a strain bearing a deletion in ORF PA1785 failed to grow on nitrate. PA1785 was identified as a homologue of the Azotobacter vinelandii nasT gene, the product of which is required for transcription of the A. vinelandii nitrite/nitrate reductase operon. Collectively, these studies reveal that transcriptional antitermination of the leader RNA NalA is required for expression of the PAO1 nitrate assimilation operon, and that this process is governed by conserved functions in PAO1 and A. vinelandii.
authors.affiliation: Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Romeo
authors.affiliation: Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Sonnleitner
authors.affiliation: Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria.
authors.forename: Theresa
authors.initials: T
authors.lastname: Sorger-Domenigg
authors.affiliation: Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Bioinformatics Institute, Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01 Matrix, 138671 Singapore.
authors.forename: Birgit
authors.initials: B
authors.lastname: Eisenhaber
authors.affiliation: Max F. Perutz Laboratories, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Dr. Bohrgasse 9/4, 1030 Vienna, Austria.
authors.forename: Udo
authors.initials: U
authors.lastname: Bläsi
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D050901:Nitrate Reductase / Q000235:genetics* / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D009876:Operon; D011401:Promoter Regions, Genetic; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D009566:Nitrates; D015534:Trans-Activators; D050901:Nitrate Reductase