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Naville M, Gautheret D. Transcription attenuation in bacteria: theme and variations. BRIEFINGS IN FUNCTIONAL GENOMICS AND PROTEOMICS 2009; 8:482-92. [PMID: 19651704 DOI: 10.1093/bfgp/elp025] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Premature termination of transcription, or attenuation, is an efficient RNA-based regulatory strategy that is commonly used in bacterial organisms. Attenuators are generally located in the 5' untranslated regions of genes or operons and combine a Rho-independent terminator, controlling transcription, with an RNA element that senses specific environmental signals. A striking diversity of sensing elements enable regulation of gene expression in response to multiple environmental conditions, including temperature changes, availability of small metabolites (such as ions, amino acids, nucleobases or vitamins), or availability of macromolecules such as tRNAs and regulatory proteins. The wide distribution of attenuators suggests an early emergence among bacteria. However, attenuators also display a great mobility and lability, illustrated by a multiplicity of recent horizontal transfers and duplications. For these reasons, attenuation systems are of high interest both from a fundamental evolutionary perspective and for possible biotechnological applications.
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Affiliation(s)
- Magali Naville
- Institut de Génétique et de Microbiologie, Paris-Sud University, Bâtiment 400, F-91405 Orsay Cedex, France
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102
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Abstract
The cellular concentrations of certain metabolites are assiduously monitored to achieve appropriate levels of gene expression. Although proteins have long been known to act as sensors in this capacity, metabolite-binding RNAs, or riboswitches, also play an important role. More than 20 distinct classes of riboswitches have been identified to date, and insights to the molecular recognition strategies of a significant subset of these have been provided by detailed structural studies. This diverse set of metabolite-sensing RNAs is found to exploit a variety of distinct mechanisms to regulate genes that are fundamental to metabolism.
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Affiliation(s)
- Adam Roth
- Howard Hughes Medical Institute, Yale University, New Haven, CT 06520-8103, USA.
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103
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Barbe V, Cruveiller S, Kunst F, Lenoble P, Meurice G, Sekowska A, Vallenet D, Wang T, Moszer I, Médigue C, Danchin A. From a consortium sequence to a unified sequence: the Bacillus subtilis 168 reference genome a decade later. MICROBIOLOGY (READING, ENGLAND) 2009; 155:1758-1775. [PMID: 19383706 PMCID: PMC2885750 DOI: 10.1099/mic.0.027839-0] [Citation(s) in RCA: 257] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 02/25/2009] [Accepted: 02/25/2009] [Indexed: 11/18/2022]
Abstract
Comparative genomics is the cornerstone of identification of gene functions. The immense number of living organisms precludes experimental identification of functions except in a handful of model organisms. The bacterial domain is split into large branches, among which the Firmicutes occupy a considerable space. Bacillus subtilis has been the model of Firmicutes for decades and its genome has been a reference for more than 10 years. Sequencing the genome involved more than 30 laboratories, with different expertises, in a attempt to make the most of the experimental information that could be associated with the sequence. This had the expected drawback that the sequencing expertise was quite varied among the groups involved, especially at a time when sequencing genomes was extremely hard work. The recent development of very efficient, fast and accurate sequencing techniques, in parallel with the development of high-level annotation platforms, motivated the present resequencing work. The updated sequence has been reannotated in agreement with the UniProt protein knowledge base, keeping in perspective the split between the paleome (genes necessary for sustaining and perpetuating life) and the cenome (genes required for occupation of a niche, suggesting here that B. subtilis is an epiphyte). This should permit investigators to make reliable inferences to prepare validation experiments in a variety of domains of bacterial growth and development as well as build up accurate phylogenies.
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Affiliation(s)
- Valérie Barbe
- CEA, Institut de Génomique, Génoscope, 2 rue Gaston Crémieux, 91057 Évry, France
| | - Stéphane Cruveiller
- CEA, Institut de Génomique, Laboratoire de Génomique Comparative/CNRS UMR8030, Génoscope, 2 rue Gaston Crémieux, 91057 Évry, France
| | - Frank Kunst
- CEA, Institut de Génomique, Génoscope, 2 rue Gaston Crémieux, 91057 Évry, France
| | - Patricia Lenoble
- CEA, Institut de Génomique, Génoscope, 2 rue Gaston Crémieux, 91057 Évry, France
| | - Guillaume Meurice
- Institut Pasteur, Intégration et Analyse Génomiques, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Agnieszka Sekowska
- Institut Pasteur, Génétique des Génomes Bactériens/CNRS URA2171, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - David Vallenet
- CEA, Institut de Génomique, Laboratoire de Génomique Comparative/CNRS UMR8030, Génoscope, 2 rue Gaston Crémieux, 91057 Évry, France
| | - Tingzhang Wang
- Institut Pasteur, Génétique des Génomes Bactériens/CNRS URA2171, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Ivan Moszer
- Institut Pasteur, Intégration et Analyse Génomiques, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Claudine Médigue
- CEA, Institut de Génomique, Laboratoire de Génomique Comparative/CNRS UMR8030, Génoscope, 2 rue Gaston Crémieux, 91057 Évry, France
| | - Antoine Danchin
- Institut Pasteur, Génétique des Génomes Bactériens/CNRS URA2171, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France
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104
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Abstract
Riboswitches are RNA elements that undergo a shift in structure in response to binding of a regulatory molecule. These elements are encoded within the transcript they regulate, and act in cis to control expression of the coding sequence(s) within that transcript; their function is therefore distinct from that of small regulatory RNAs (sRNAs) that act in trans to regulate the activity of other RNA transcripts. Riboswitch RNAs control a broad range of genes in bacterial species, including those involved in metabolism or uptake of amino acids, cofactors, nucleotides, and metal ions. Regulation occurs as a consequence of direct binding of an effector molecule, or through sensing of a physical parameter such as temperature. Here we review the global role of riboswitch RNAs in bacterial cell metabolism.
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Affiliation(s)
- Tina M Henkin
- Department of Microbiology, The Ohio State University, Columbus, Ohio 43210, USA.
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