1
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Metaane S, Monteil V, Douché T, Giai Gianetto Q, Matondo M, Maufrais C, Norel F. Loss of CorA, the primary magnesium transporter of Salmonella, is alleviated by MgtA and PhoP-dependent compensatory mechanisms. PLoS One 2023; 18:e0291736. [PMID: 37713445 PMCID: PMC10503707 DOI: 10.1371/journal.pone.0291736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023] Open
Abstract
In many Gram-negative bacteria, the stress sigma factor of RNA polymerase, σS/RpoS, remodels global gene expression to reshape the physiology of stationary phase cells and ensure their survival under non-optimal growth conditions. In the foodborne pathogen Salmonella enterica serovar Typhimurium, σS is also required for biofilm formation and virulence. We have recently shown that a ΔrpoS mutation decreases the magnesium content and expression level of the housekeeping Mg2+-transporter CorA in stationary phase Salmonella. The other two Mg2+-transporters of Salmonella are encoded by the PhoP-activated mgtA and mgtB genes and are expressed under magnesium starvation. The σS control of corA prompted us to evaluate the impact of CorA in stationary phase Salmonella cells, by using global and analytical proteomic analyses and physiological assays. The ΔcorA mutation conferred a competitive disadvantage to exit from stationary phase, and slightly impaired motility, but had no effect on total and free cellular magnesium contents. In contrast to the wild-type strain, the ΔcorA mutant produced MgtA, but not MgtB, in the presence of high extracellular magnesium concentration. Under these conditions, MgtA production in the ΔcorA mutant did not require PhoP. Consistently, a ΔmgtA, but not a ΔphoP, mutation slightly reduced the magnesium content of the ΔcorA mutant. Synthetic phenotypes were observed when the ΔphoP and ΔcorA mutations were combined, including a strong reduction in growth and motility, independently of the extracellular magnesium concentration. The abundance of several proteins involved in flagella formation, chemotaxis and secretion was lowered by the ΔcorA and ΔphoP mutations in combination, but not alone. These findings unravel the importance of PhoP-dependent functions in the absence of CorA when magnesium is sufficient. Altogether, our data pinpoint a regulatory network, where the absence of CorA is sensed by the cell and compensated by MgtA and PhoP- dependent mechanisms.
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Affiliation(s)
- Selma Metaane
- Biochimie des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3528, Université Paris Cité, Paris, France
| | - Véronique Monteil
- Biochimie des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3528, Université Paris Cité, Paris, France
| | - Thibaut Douché
- Proteomic Platform, Mass Spectrometry for Biology Unit, Institut Pasteur, CNRS UAR 2024, Université Paris Cité, Paris, France
| | - Quentin Giai Gianetto
- Proteomic Platform, Mass Spectrometry for Biology Unit, Institut Pasteur, CNRS UAR 2024, Université Paris Cité, Paris, France
| | - Mariette Matondo
- Proteomic Platform, Mass Spectrometry for Biology Unit, Institut Pasteur, CNRS UAR 2024, Université Paris Cité, Paris, France
| | - Corinne Maufrais
- Bioinformatics and Biostatistics Hub, Institut Pasteur, Université Paris Cité, Paris, France
| | - Françoise Norel
- Biochimie des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3528, Université Paris Cité, Paris, France
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2
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Qin H, Liu Y, Cao X, Jiang J, Lian W, Qiao D, Xu H, Cao Y. RpoS is a pleiotropic regulator of motility, biofilm formation, exoenzymes, siderophore and prodigiosin production, and trade-off during prolonged stationary phase in Serratia marcescens. PLoS One 2020; 15:e0232549. [PMID: 32484808 PMCID: PMC7266296 DOI: 10.1371/journal.pone.0232549] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 04/16/2020] [Indexed: 02/07/2023] Open
Abstract
Prodigiosin is an important secondary metabolite produced by Serratia marcescens. It can help strains resist stresses from other microorganisms and environmental factors to achieve self-preservation. Prodigiosin is also a promising secondary metabolite due to its pharmacological characteristics. However, pigmentless S. marcescens mutants always emerge after prolonged starvation, which might be a way for the bacteria to adapt to starvation conditions, but it could be a major problem in the industrial application of S. marcescens. To identify the molecular mechanisms of loss of prodigiosin production, two mutants were isolated after 16 days of prolonged incubation of wild-type (WT) S. marcescens 1912768R; one mutant (named 1912768WR) exhibited reduced production of prodigiosin, and a second mutant (named 1912768W) was totally defective. Comparative genomic analysis revealed that the two mutants had either mutations or deletions in rpoS. Knockout of rpoS in S. marcescens 1912768R had pleiotropic effects. Complementation of rpoS in the ΔrpoS mutant further confirmed that RpoS was a positive regulator of prodigiosin production and that its regulatory role in prodigiosin biosynthesis was opposite that in Serratia sp. ATCC 39006, which had a different type of pig cluster; further, rpoS from Serratia sp. ATCC 39006 and other strains complemented the prodigiosin defect of the ΔrpoS mutant, suggesting that the pig promoters are more important than the genes in the regulation of prodigiosin production. Deletion of rpoS strongly impaired the resistance of S. marcescens to stresses but increased membrane permeability for nutritional competence; competition assays in rich and minimum media showed that the ΔrpoS mutant outcompeted its isogenic WT strain. All these data support the idea that RpoS is pleiotropic and that the loss of prodigiosin biosynthesis in S. marcescens 1912768R during prolonged incubation is due to a mutation in rpoS, which appears to be a self-preservation and nutritional competence (SPANC) trade-off.
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Affiliation(s)
- Han Qin
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Ying Liu
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Xiyue Cao
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Jia Jiang
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Weishao Lian
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Dairong Qiao
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
| | - Hui Xu
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
- * E-mail: (YC); (HX)
| | - Yi Cao
- Microbiology and Metabolic Engineering of Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, P.R. China
- * E-mail: (YC); (HX)
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3
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Xu J, Cui K, Shen L, Shi J, Li L, You L, Fang C, Zhao G, Feng Y, Yang B, Zhang Y. Crl activates transcription by stabilizing active conformation of the master stress transcription initiation factor. eLife 2019; 8:50928. [PMID: 31846423 PMCID: PMC6917491 DOI: 10.7554/elife.50928] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/03/2019] [Indexed: 12/20/2022] Open
Abstract
σS is a master transcription initiation factor that protects bacterial cells from various harmful environmental stresses including antibiotic pressure. Although its mechanism remains unclear, it is known that full activation of σS-mediated transcription requires a σS-specific activator, Crl. In this study, we determined a 3.80 Å cryo-EM structure of an Escherichia coli transcription activation complex (E. coli Crl-TAC) comprising E. coli σS-RNA polymerase (σS-RNAP) holoenzyme, Crl, and a nucleic-acid scaffold. The structure reveals that Crl interacts with domain 2 of σS (σS2) and the RNAP core enzyme, but does not contact promoter DNA. Results from subsequent hydrogen-deuterium exchange mass spectrometry (HDX-MS) indicate that Crl stabilizes key structural motifs within σS2 to promote the assembly of the σS-RNAP holoenzyme and also to facilitate formation of an RNA polymerase–promoter DNA open complex (RPo). Our study demonstrates a unique DNA contact-independent mechanism of transcription activation, thereby defining a previously unrecognized mode of transcription activation in cells.
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Affiliation(s)
- Juncao Xu
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Kaijie Cui
- University of Chinese Academy of Sciences, Beijing, China.,Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Liqiang Shen
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jing Shi
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, China.,Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lingting Li
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Linlin You
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Chengli Fang
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Guoping Zhao
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.,Shanghai-MOST Key Laboratory of Health and Disease Genomics, Chinese National Human Genome Center at Shanghai, Shanghai, China.,Department of Microbiology, Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, China.,State Key Laboratory of Genetic Engineering, Department of Microbiology, School of Life Sciences, Fudan University, Shanghai, China.,Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Yu Feng
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, China.,Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bei Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology,CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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4
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The stress sigma factor of RNA polymerase RpoS/σS is a solvent-exposed open molecule in solution. Biochem J 2018; 475:341-354. [DOI: 10.1042/bcj20170768] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/05/2017] [Accepted: 12/07/2017] [Indexed: 11/17/2022]
Abstract
In bacteria, one primary and multiple alternative sigma (σ) factors associate with the RNA polymerase core enzyme (E) to form holoenzymes (Eσ) with different promoter recognition specificities. The alternative σ factor RpoS/σS is produced in stationary phase and under stress conditions and reprograms global gene expression to promote bacterial survival. To date, the three-dimensional structure of a full-length free σ factor remains elusive. The current model suggests that extensive interdomain contacts in a free σ factor result in a compact conformation that masks the DNA-binding determinants of σ, explaining why a free σ factor does not bind double-stranded promoter DNA efficiently. Here, we explored the solution conformation of σS using amide hydrogen/deuterium exchange coupled with mass spectrometry, NMR, analytical ultracentrifugation and molecular dynamics. Our data strongly argue against a compact conformation of free σS. Instead, we show that σS adopts an open conformation in solution in which the folded σ2 and σ4 domains are interspersed by domains with a high degree of disorder. These findings suggest that E binding induces major changes in both the folding and domain arrangement of σS and provide insights into the possible mechanisms of regulation of σS activity by its chaperone Crl.
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5
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Cavaliere P, Norel F. Recent advances in the characterization of Crl, the unconventional activator of the stress sigma factor σS/RpoS. Biomol Concepts 2017; 7:197-204. [PMID: 27180360 DOI: 10.1515/bmc-2016-0006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 03/29/2016] [Indexed: 11/15/2022] Open
Abstract
The bacterial RNA polymerase (RNAP) holoenzyme is a multisubunit core enzyme associated with a σ factor that is required for promoter-specific transcription initiation. Besides a primary σ responsible for most of the gene expression during active growth, bacteria contain alternative σ factors that control adaptive responses. A recurring strategy in the control of σ factor activity is their sequestration by anti-sigma factors that occlude the RNAP binding determinants, reducing their activity. In contrast, the unconventional transcription factor Crl binds specifically to the alternative σ factor σS/RpoS, and favors its association with the core RNAP, thereby increasing its activity. σS is the master regulator of the general stress response that protects many Gram-negative bacteria from several harmful environmental conditions. It is also required for biofilm formation and virulence of Salmonella enterica serovar Typhimurium. In this report, we discuss current knowledge on the regulation and function of Crl in Salmonella and Escherichia coli, two bacterial species in which Crl has been studied. We review recent advances in the structural characterization of the Crl-σS interaction that have led to a better understanding of this unusual mechanism of σ regulation.
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6
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Xue X, Davis MC, Steeves T, Bishop A, Breen J, MacEacheron A, Kesthely CA, Hsu F, MacLellan SR. Characterization of a protein-protein interaction within the SigO-RsoA two-subunit σ factor: the σ70 region 2.3-like segment of RsoA mediates interaction with SigO. MICROBIOLOGY-SGM 2016; 162:1857-1869. [PMID: 27558998 DOI: 10.1099/mic.0.000358] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
σ factors are single subunit general transcription factors that reversibly bind core RNA polymerase and mediate gene-specific transcription in bacteria. Previously, an atypical two-subunit σ factor was identified that activates transcription from a group of related promoters in Bacillus subtilis. Both of the subunits, named SigO and RsoA, share primary sequence similarity with the canonical σ70 family of σ factors and interact with each other and with RNA polymerase subunits. Here we show that the σ70 region 2.3-like segment of RsoA is unexpectedly sufficient for interaction with the amino-terminus of SigO and the β' subunit. A mutational analysis of RsoA identified aromatic residues conserved amongst all RsoA homologues, and often amongst canonical σ factors, that are particularly important for the SigO-RsoA interaction. In a canonical σ factor, region 2.3 amino acids bind non-template strand DNA, trapping the promoter in a single-stranded state required for initiation of transcription. Accordingly, we speculate that RsoA region 2.3 protein-binding activity likely arose from a motif that, at least in its ancestral protein, participated in DNA-binding interactions.
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Affiliation(s)
- Xiaowei Xue
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | - Maria C Davis
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | - Thomas Steeves
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | - Adam Bishop
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | - Jillian Breen
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | | | | | - FoSheng Hsu
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
| | - Shawn R MacLellan
- Department of Biology, University of New Brunswick, Fredericton, NB, Canada
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7
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Cavaliere P, Norel F, Sizun C. (1)H, (13)C and (15)N resonance assignments of σ(S) activating protein Crl from Salmonella enterica serovar Typhimurium. BIOMOLECULAR NMR ASSIGNMENTS 2015; 9:397-401. [PMID: 25943268 DOI: 10.1007/s12104-015-9617-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Accepted: 04/30/2015] [Indexed: 06/04/2023]
Abstract
The general stress response in Enterobacteria, like Escherichia coli or Salmonella, is controlled by the transcription factor σ(S), encoded by the rpoS gene, which accumulates during stationary phase growth and associates with the core RNA polymerase enzyme (E) to promote transcription of genes involved in cell survival. Tight regulation of σ(S) is essential to preserve the balance between self-preservation under stress conditions and nutritional competence in the absence of stress. Whereas σ factors are generally inactivated upon interaction with anti-sigma proteins, σ(S) binding by the Crl protein facilitates the formation of the holoenzyme Eσ(S), and therefore σ(S)-controlled transcription. Previously, critical residues in both Crl and σ(S) were identified and assigned to the binding interface in the Crl-σ(S) complex. However, high-resolution structural data are missing to fully understand the molecular mechanisms underlying σ(S) activation by Crl, in particular the possible role of Crl in triggering domain rearrangements in the multi-domain protein σ(S). Here we provide the (1)H, (13)C and (15)N resonance assignments of Salmonella enterica serovar Typhimurium Crl, as a starting point for CrlSTM structure determination and further structural investigation of the CrlSTM-σ STM (S) complex.
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Affiliation(s)
- Paola Cavaliere
- Département de Microbiologie, Laboratoire Systèmes Macromoléculaires et Signalisation, Institut Pasteur, 25 rue du Docteur Roux, 75015, Paris, France
- CNRS ERL3526, rue du Docteur Roux, 75015, Paris, France
| | - Françoise Norel
- Département de Microbiologie, Laboratoire Systèmes Macromoléculaires et Signalisation, Institut Pasteur, 25 rue du Docteur Roux, 75015, Paris, France
- CNRS ERL3526, rue du Docteur Roux, 75015, Paris, France
| | - Christina Sizun
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, 91190, Gif-sur-Yvette, France.
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8
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Binding interface between the Salmonella σ(S)/RpoS subunit of RNA polymerase and Crl: hints from bacterial species lacking crl. Sci Rep 2015; 5:13564. [PMID: 26338235 PMCID: PMC4559669 DOI: 10.1038/srep13564] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 07/30/2015] [Indexed: 01/30/2023] Open
Abstract
In many Gram-negative bacteria, including Salmonella enterica serovar Typhimurium (S. Typhimurium), the sigma factor RpoS/σS accumulates during stationary phase of growth, and associates with the core RNA polymerase enzyme (E) to promote transcription initiation of genes involved in general stress resistance and starvation survival. Whereas σ factors are usually inactivated upon interaction with anti-σ proteins, σS binding to the Crl protein increases σS activity by favouring its association to E. Taking advantage of evolution of the σS sequence in bacterial species that do not contain a crl gene, like Pseudomonas aeruginosa, we identified and assigned a critical arginine residue in σS to the S. Typhimurium σS-Crl binding interface. We solved the solution structure of S. Typhimurium Crl by NMR and used it for NMR binding assays with σS and to generate in silico models of the σS-Crl complex constrained by mutational analysis. The σS-Crl models suggest that the identified arginine in σS interacts with an aspartate of Crl that is required for σS binding and is located inside a cavity enclosed by flexible loops, which also contribute to the interface. This study provides the basis for further structural investigation of the σS-Crl complex.
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9
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Lévi-Meyrueis C, Monteil V, Sismeiro O, Dillies MA, Kolb A, Monot M, Dupuy B, Duarte SS, Jagla B, Coppée JY, Beraud M, Norel F. Repressor activity of the RpoS/σS-dependent RNA polymerase requires DNA binding. Nucleic Acids Res 2015; 43:1456-68. [PMID: 25578965 PMCID: PMC4330354 DOI: 10.1093/nar/gku1379] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The RpoS/σ(S) sigma subunit of RNA polymerase (RNAP) activates transcription of stationary phase genes in many Gram-negative bacteria and controls adaptive functions, including stress resistance, biofilm formation and virulence. In this study, we address an important but poorly understood aspect of σ(S)-dependent control, that of a repressor. Negative regulation by σ(S) has been proposed to result largely from competition between σ(S) and other σ factors for binding to a limited amount of core RNAP (E). To assess whether σ(S) binding to E alone results in significant downregulation of gene expression by other σ factors, we characterized an rpoS mutant of Salmonella enterica serovar Typhimurium producing a σ(S) protein proficient for Eσ(S) complex formation but deficient in promoter DNA binding. Genome expression profiling and physiological assays revealed that this mutant was defective for negative regulation, indicating that gene repression by σ(S) requires its binding to DNA. Although the mechanisms of repression by σ(S) are likely specific to individual genes and environmental conditions, the study of transcription downregulation of the succinate dehydrogenase operon suggests that σ competition at the promoter DNA level plays an important role in gene repression by Eσ(S).
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Affiliation(s)
- Corinne Lévi-Meyrueis
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France CNRS ERL3526, rue du Docteur Roux, 75015 Paris, France Université Paris Sud XI, 15, rue Georges Clémenceau, 91405 Orsay Cedex, France
| | - Véronique Monteil
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France CNRS ERL3526, rue du Docteur Roux, 75015 Paris, France
| | - Odile Sismeiro
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, rue du Docteur Roux, 75015 Paris, France
| | - Marie-Agnès Dillies
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, rue du Docteur Roux, 75015 Paris, France
| | - Annie Kolb
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France CNRS ERL3526, rue du Docteur Roux, 75015 Paris, France
| | - Marc Monot
- Institut Pasteur, Laboratoire Pathogenèse des bactéries anaérobies, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France
| | - Bruno Dupuy
- Institut Pasteur, Laboratoire Pathogenèse des bactéries anaérobies, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France
| | - Sara Serradas Duarte
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France CNRS ERL3526, rue du Docteur Roux, 75015 Paris, France
| | - Bernd Jagla
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, rue du Docteur Roux, 75015 Paris, France
| | - Jean-Yves Coppée
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, rue du Docteur Roux, 75015 Paris, France
| | - Mélanie Beraud
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France CNRS ERL3526, rue du Docteur Roux, 75015 Paris, France Université Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris, rue du Docteur Roux, 75015 Paris, France
| | - Françoise Norel
- Institut Pasteur, Laboratoire Systèmes Macromoléculaires et Signalisation, Département de Microbiologie, rue du Docteur Roux, 75015 Paris, France CNRS ERL3526, rue du Docteur Roux, 75015 Paris, France
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10
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Structural and functional features of Crl proteins and identification of conserved surface residues required for interaction with the RpoS/σS subunit of RNA polymerase. Biochem J 2014; 463:215-24. [PMID: 25056110 DOI: 10.1042/bj20140578] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In many γ-proteobacteria, the RpoS/σS sigma factor associates with the core RNAP (RNA polymerase) to modify global gene transcription in stationary phase and under stress conditions. The small regulatory protein Crl stimulates the association of σS with the core RNAP in Escherichia coli and Salmonella enterica serovar Typhimurium, through direct and specific interaction with σS. The structural determinants of Crl involved in σS binding are unknown. In the present paper we report the X-ray crystal structure of the Proteus mirabilis Crl protein (CrlPM) and a structural model for Salmonella Typhimurium Crl (CrlSTM). Using a combination of in vivo and in vitro assays, we demonstrated that CrlSTM and CrlPM are structurally similar and perform the same biological function. In the Crl structure, a cavity enclosed by flexible arms contains two patches of conserved and exposed residues required for σS binding. Among these, charged residues that are likely to be involved in electrostatic interactions driving Crl-σS complex formation were identified. CrlSTM and CrlPM interact with domain 2 of σS with the same binding properties as with full-length σS. These results suggest that Crl family members share a common mechanism of σS binding in which the flexible arms of Crl might play a dynamic role.
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11
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Structure of the RNA polymerase assembly factor Crl and identification of its interaction surface with sigma S. J Bacteriol 2014; 196:3279-88. [PMID: 25002538 DOI: 10.1128/jb.01910-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria utilize multiple sigma factors that associate with core RNA polymerase (RNAP) to control transcription in response to changes in environmental conditions. In Escherichia coli and Salmonella enterica, Crl positively regulates the σ(S) regulon by binding to σ(S) to promote its association with core RNAP. We recently characterized the determinants in σ(S) responsible for specific binding to Crl. However, little is known about the determinants in Crl required for this interaction. Here, we present the X-ray crystal structure of a Crl homolog from Proteus mirabilis in conjunction with in vivo and in vitro approaches that probe the Crl-σ(S) interaction in E. coli. We show that the P. mirabilis, Vibrio harveyi, and E. coli Crl homologs function similarly in E. coli, indicating that Crl structure and function are likely conserved throughout gammaproteobacteria. We utilize phylogenetic conservation and bacterial two-hybrid analyses to predict residues in Crl important for the interaction with σ(S). The results of p-benzoylphenylalanine (BPA)-mediated UV cross-linking studies further support the model in which an evolutionarily conserved central cleft is the surface on Crl that binds to σ(S). Within this conserved binding surface, we identify a key residue in Crl that is critical for activation of Eσ(S)-dependent transcription in vivo and in vitro. Our study provides a physical basis for understanding the σ(S)-Crl interaction.
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Lévi-Meyrueis C, Monteil V, Sismeiro O, Dillies MA, Monot M, Jagla B, Coppée JY, Dupuy B, Norel F. Expanding the RpoS/σS-network by RNA sequencing and identification of σS-controlled small RNAs in Salmonella. PLoS One 2014; 9:e96918. [PMID: 24810289 PMCID: PMC4014581 DOI: 10.1371/journal.pone.0096918] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 04/13/2014] [Indexed: 12/31/2022] Open
Abstract
The RpoS/σS sigma subunit of RNA polymerase (RNAP) controls a global adaptive response that allows many Gram-negative bacteria to survive starvation and various stresses. σS also contributes to biofilm formation and virulence of the food-borne pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium). In this study, we used directional RNA-sequencing and complementary assays to explore the σS-dependent transcriptome of S. Typhimurium during late stationary phase in rich medium. This study confirms the large regulatory scope of σS and provides insights into the physiological functions of σS in Salmonella. Extensive regulation by σS of genes involved in metabolism and membrane composition, and down-regulation of the respiratory chain functions, were important features of the σS effects on gene transcription that might confer fitness advantages to bacterial cells and/or populations under starving conditions. As an example, we show that arginine catabolism confers a competitive fitness advantage in stationary phase. This study also provides a firm basis for future studies to address molecular mechanisms of indirect regulation of gene expression by σS. Importantly, the σS-controlled downstream network includes small RNAs that might endow σS with post-transcriptional regulatory functions. Of these, four (RyhB-1/RyhB-2, SdsR, SraL) were known to be controlled by σS and deletion of the sdsR locus had a competitive fitness cost in stationary phase. The σS-dependent control of seven additional sRNAs was confirmed in Northern experiments. These findings will inspire future studies to investigate molecular mechanisms and the physiological impact of post-transcriptional regulation by σS.
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Affiliation(s)
- Corinne Lévi-Meyrueis
- Institut Pasteur, Unité de Génétique Moléculaire, Département de Microbiologie, Paris, France
- CNRS, ERL3526, Paris, France
- Université Paris Sud XI, Orsay, France
| | - Véronique Monteil
- Institut Pasteur, Unité de Génétique Moléculaire, Département de Microbiologie, Paris, France
- CNRS, ERL3526, Paris, France
| | - Odile Sismeiro
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, Paris, France
| | - Marie-Agnès Dillies
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, Paris, France
| | - Marc Monot
- Institut Pasteur, Laboratoire Pathogenèse des bactéries anaérobies, Département de Microbiologie, Paris, France
| | - Bernd Jagla
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, Paris, France
| | - Jean-Yves Coppée
- Institut Pasteur, Plate-forme Transcriptome et Epigénome, Département Génomes et génétique, Paris, France
| | - Bruno Dupuy
- Institut Pasteur, Laboratoire Pathogenèse des bactéries anaérobies, Département de Microbiologie, Paris, France
| | - Françoise Norel
- Institut Pasteur, Unité de Génétique Moléculaire, Département de Microbiologie, Paris, France
- CNRS, ERL3526, Paris, France
- * E-mail:
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Key features of σS required for specific recognition by Crl, a transcription factor promoting assembly of RNA polymerase holoenzyme. Proc Natl Acad Sci U S A 2013; 110:15955-60. [PMID: 24043782 DOI: 10.1073/pnas.1311642110] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Bacteria use multiple sigma factors to coordinate gene expression in response to environmental perturbations. In Escherichia coli and other γ-proteobacteria, the transcription factor Crl stimulates σ(S)-dependent transcription during times of cellular stress by promoting the association of σ(S) with core RNA polymerase. The molecular basis for specific recognition of σ(S) by Crl, rather than the homologous and more abundant primary sigma factor σ(70), is unknown. Here we use bacterial two-hybrid analysis in vivo and p-benzoyl-phenylalanine cross-linking in vitro to define the features in σ(S) responsible for specific recognition by Crl. We identify residues in σ(S) conserved domain 2 (σ(S)2) that are necessary and sufficient to allow recognition of σ(70) conserved domain 2 by Crl, one near the promoter-melting region and the other at the position where a large nonconserved region interrupts the sequence of σ(70). We then use luminescence resonance energy transfer to demonstrate directly that Crl promotes holoenzyme assembly using these specificity determinants on σ(S). Our results explain how Crl distinguishes between sigma factors that are largely homologous and activates discrete sets of promoters even though it does not bind to promoter DNA.
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Tabib-Salazar A, Liu B, Doughty P, Lewis RA, Ghosh S, Parsy ML, Simpson PJ, O'Dwyer K, Matthews SJ, Paget MS. The actinobacterial transcription factor RbpA binds to the principal sigma subunit of RNA polymerase. Nucleic Acids Res 2013; 41:5679-91. [PMID: 23605043 PMCID: PMC3675491 DOI: 10.1093/nar/gkt277] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
RbpA is a small non–DNA-binding transcription factor that associates with RNA polymerase holoenzyme and stimulates transcription in actinobacteria, including Streptomyces coelicolor and Mycobacterium tuberculosis. RbpA seems to show specificity for the vegetative form of RNA polymerase as opposed to alternative forms of the enzyme. Here, we explain the basis of this specificity by showing that RbpA binds directly to the principal σ subunit in these organisms, but not to more diverged alternative σ factors. Nuclear magnetic resonance spectroscopy revealed that, although differing in their requirement for structural zinc, the RbpA orthologues from S. coelicolor and M. tuberculosis share a common structural core domain, with extensive, apparently disordered, N- and C-terminal regions. The RbpA–σ interaction is mediated by the C-terminal region of RbpA and σ domain 2, and S. coelicolor RbpA mutants that are defective in binding σ are unable to stimulate transcription in vitro and are inactive in vivo. Given that RbpA is essential in M. tuberculosis and critical for growth in S. coelicolor, these data support a model in which RbpA plays a key role in the σ cycle in actinobacteria.
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Battesti A, Bouveret E. The bacterial two-hybrid system based on adenylate cyclase reconstitution in Escherichia coli. Methods 2012; 58:325-34. [PMID: 22841567 DOI: 10.1016/j.ymeth.2012.07.018] [Citation(s) in RCA: 245] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2011] [Revised: 05/29/2012] [Accepted: 07/13/2012] [Indexed: 10/28/2022] Open
Abstract
The bacterial two-hybrid system based on the reconstitution of adenylate cyclase in Escherichia coli (BACTH) was described 14years ago (Karimova, Pidoux, Ullmann, and Ladant, 1998, PNAS, 95:5752). For microbiologists, it is a practical and powerful alternative to the use of the widely spread yeast two-hybrid technology for testing protein-protein interactions. In this review, we aim at giving the reader clear and most importantly simple instructions that should break any reticence to try the technique. Yet, we also add recommendations in the use of the system, related to its specificities. Finally, we expose the advantages and disadvantages of the technique, and review its diverse applications in the literature, which should help in deciding if it is the appropriate method to choose for the case at hand.
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Abstract
In their stressful natural environments, bacteria often are in stationary phase and use their limited resources for maintenance and stress survival. Underlying this activity is the general stress response, which in Escherichia coli depends on the σS (RpoS) subunit of RNA polymerase. σS is closely related to the vegetative sigma factor σ70 (RpoD), and these two sigmas recognize similar but not identical promoter sequences. During the postexponential phase and entry into stationary phase, σS is induced by a fine-tuned combination of transcriptional, translational, and proteolytic control. In addition, regulatory "short-cuts" to high cellular σS levels, which mainly rely on the rapid inhibition of σS proteolysis, are triggered by sudden starvation for various nutrients and other stressful shift conditons. σS directly or indirectly activates more than 500 genes. Additional signal input is integrated by σS cooperating with various transcription factors in complex cascades and feedforward loops. Target gene products have stress-protective functions, redirect metabolism, affect cell envelope and cell shape, are involved in biofilm formation or pathogenesis, or can increased stationary phase and stress-induced mutagenesis. This review summarizes these diverse functions and the amazingly complex regulation of σS. At the molecular level, these processes are integrated with the partitioning of global transcription space by sigma factor competition for RNA polymerase core enzyme and signaling by nucleotide second messengers that include cAMP, (p)ppGpp, and c-di-GMP. Physiologically, σS is the key player in choosing between a lifestyle associated with postexponential growth based on nutrient scavenging and motility and a lifestyle focused on maintenance, strong stress resistance, and increased adhesiveness. Finally, research with other proteobacteria is beginning to reveal how evolution has further adapted function and regulation of σS to specific environmental niches.
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