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Arvizu-Gómez JL, Hernández-Morales A, Campos-Guillén J, González-Reyes C, Pacheco-Aguilar JR. Phaseolotoxin: Environmental Conditions and Regulatory Mechanisms Involved in Its Synthesis. Microorganisms 2024; 12:1300. [PMID: 39065068 PMCID: PMC11278893 DOI: 10.3390/microorganisms12071300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/12/2024] [Accepted: 06/24/2024] [Indexed: 07/28/2024] Open
Abstract
Phaseolotoxin is an antimetabolite toxin produced by diverse pathovars of Pseudomonas syringae which affects various plants, causing diseases of economic importance. Phaseolotoxin contributes to the systemic dissemination of the pathogen in the plant, therefore it is recognized as a major virulence factor. Genetic traits such as the Pht cluster, appear defining to the toxigenic strains phaseolotoxin producers. Extensive research has contributed to our knowledge concerning the regulation of phaseolotoxin revealing a complex regulatory network that involves processes at the transcriptional and posttranscriptional levels, in which specific and global regulators participate. Even more, significant advances in understanding how specific signals, including host metabolites, nutrient sources, and physical parameters such as the temperature, can affect phaseolotoxin production have been made. A general overview of the phaseolotoxin regulation, focusing on the chemical and physical cues, and regulatory pathways involved in the expression of this major virulence factor will be given in the present work.
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Affiliation(s)
- Jackeline Lizzeta Arvizu-Gómez
- Secretaría de Investigación y Posgrado, Centro Nayarita de Innovación y Transferencia de Tecnología (CENITT), Universidad Autónoma de Nayarit, Tepic 63000, Mexico
| | - Alejandro Hernández-Morales
- Facultad de Estudios Profesionales Zona Huasteca, Universidad Autónoma de San Luis Potosí, Ciudad Valles 79060, Mexico
| | - Juan Campos-Guillén
- Facultad de Química, Universidad Autónoma de Querétaro, Santiago de Querétaro 76010, Mexico; (J.C.-G.); (J.R.P.-A.)
| | - Christian González-Reyes
- Unidad Académica de Ciencias Químico Biológico y Farmacéuticas, Universidad Autónoma de Nayarit, Tepic 63000, Mexico;
| | - Juan Ramiro Pacheco-Aguilar
- Facultad de Química, Universidad Autónoma de Querétaro, Santiago de Querétaro 76010, Mexico; (J.C.-G.); (J.R.P.-A.)
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2
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Morrison JJ, Madden EK, Banas DA, DiBiasio EC, Hansen M, Krogfelt KA, Rowley DC, Cohen PS, Camberg JL. Metabolic flux regulates growth transitions and antibiotic tolerance in uropathogenic Escherichia coli. J Bacteriol 2024; 206:e0016224. [PMID: 38814092 PMCID: PMC11332148 DOI: 10.1128/jb.00162-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 05/06/2024] [Indexed: 05/31/2024] Open
Abstract
Reducing growth and limiting metabolism are strategies that allow bacteria to survive exposure to environmental stress and antibiotics. During infection, uropathogenic Escherichia coli (UPEC) may enter a quiescent state that enables them to reemerge after the completion of successful antibiotic treatment. Many clinical isolates, including the well-characterized UPEC strain CFT073, also enter a metabolite-dependent, quiescent state in vitro that is reversible with cues, including peptidoglycan-derived peptides and amino acids. Here, we show that quiescent UPEC is antibiotic tolerant and demonstrate that metabolic flux in the tricarboxylic acid (TCA) cycle regulates the UPEC quiescent state via succinyl-CoA. We also demonstrate that the transcriptional regulator complex integration host factor and the FtsZ-interacting protein ZapE, which is important for E. coli division during stress, are essential for UPEC to enter the quiescent state. Notably, in addition to engaging FtsZ and late-stage cell division proteins, ZapE also interacts directly with TCA cycle enzymes in bacterial two-hybrid assays. We report direct interactions between the succinate dehydrogenase complex subunit SdhC, the late-stage cell division protein FtsN, and ZapE. These interactions may enable communication between oxidative metabolism and the cell division machinery in UPEC. Moreover, these interactions are conserved in an E. coli K-12 strain. This work suggests that there is coordination among the two fundamental and essential pathways that regulate overall growth, quiescence, and antibiotic susceptibility. IMPORTANCE Uropathogenic Escherichia coli (UPEC) are the leading cause of urinary tract infections (UTIs). Upon invasion into bladder epithelial cells, UPEC establish quiescent intracellular reservoirs that may lead to antibiotic tolerance and recurrent UTIs. Here, we demonstrate using an in vitro system that quiescent UPEC cells are tolerant to ampicillin and have decreased metabolism characterized by succinyl-CoA limitation. We identify the global regulator integration host factor complex and the cell division protein ZapE as critical modifiers of quiescence and antibiotic tolerance. Finally, we show that ZapE interacts with components of both the cell division machinery and the tricarboxylic acid cycle, and this interaction is conserved in non-pathogenic E. coli, establishing a novel link between cell division and metabolism.
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Affiliation(s)
- Josiah J. Morrison
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Ellen K. Madden
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Daniel A. Banas
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Eric C. DiBiasio
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Mads Hansen
- Department of Natural Science and Environment, Centre for Mathematical Modeling - Human Health and Disease, University of Roskilde, Roskilde, Denmark
| | - Karen A. Krogfelt
- Department of Natural Science and Environment, Centre for Mathematical Modeling - Human Health and Disease, University of Roskilde, Roskilde, Denmark
| | - David C. Rowley
- Department of Biomedical and Pharmaceutical Sciences, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Paul S. Cohen
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
| | - Jodi L. Camberg
- Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, Rhode Island, USA
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3
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Islam F, Mishra PP. Molecular Insight into the Structural Dynamics of Holliday Junctions Modulated by Integration Host Factor. J Phys Chem B 2024; 128:5642-5657. [PMID: 38812070 DOI: 10.1021/acs.jpcb.4c02997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
The integration host factor (IHF) in Escherichia coli is a nucleoid-associated protein with multifaceted roles that encompass DNA packaging, viral DNA integration, and recombination. IHF binds to double-stranded DNA featuring a 13-base pair (bp) consensus sequence with high affinity, causing a substantial bend of approximately 160° upon binding. Although wild-type IHF (WtIHF) is principally involved in DNA bending to facilitate foreign DNA integration into the host genome, its engineered counterpart, single-chain IHF (ScIHF), was specifically designed for genetic engineering and biotechnological applications. Our study delves into the interactions of both IHF variants with Holliday junctions (HJs), pivotal intermediates in DNA repair, and homologous recombination. HJs are dynamic structures capable of adopting open or stacked conformations, with the open conformation facilitating processes such as branch migration and strand exchange. Using microscale thermophoresis, we quantitatively assessed the binding of IHF to four-way DNA junctions that harbor specific binding sequences H' and H1. Our findings demonstrate that both IHF variants exhibit a strong affinity for HJs, signifying a structure-based recognition mechanism. Circular dichroism (CD) experiments unveiled the impact of the protein on the junction's conformation. Furthermore, single-molecule Förster resonance energy transfer (smFRET) confirmed the influence of IHF on the junction's dynamicity. Intriguingly, our results revealed that WtIHF and ScIHF binding shifts the population toward the open conformation of the junction and stabilizes it in that state. In summary, our findings underscore the robust affinity of the IHF for HJs and its capacity to stabilize the open conformation of these junctions.
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Affiliation(s)
- Farhana Islam
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
- Homi Bhabha National Institute, Mumbai 400094, India
| | - Padmaja Prasad Mishra
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India
- Homi Bhabha National Institute, Mumbai 400094, India
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4
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Chen M, Wu B, Huang Y, Wang W, Zheng Y, Shabbir S, Liu P, Dai Y, Xia M, Hu G, He M. Transcription factor shapes chromosomal conformation and regulates gene expression in bacterial adaptation. Nucleic Acids Res 2024; 52:5643-5657. [PMID: 38716861 PMCID: PMC11162768 DOI: 10.1093/nar/gkae318] [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: 10/25/2023] [Revised: 04/09/2024] [Accepted: 04/24/2024] [Indexed: 06/11/2024] Open
Abstract
Genomic mutations allow bacteria to adapt rapidly to adverse stress environments. The three-dimensional conformation of the genome may also play an important role in transcriptional regulation and environmental adaptation. Here, using chromosome conformation capture, we investigate the high-order architecture of the Zymomonas mobilis chromosome in response to genomic mutation and ambient stimuli (acetic acid and furfural, derived from lignocellulosic hydrolysate). We find that genomic mutation only influences the local chromosome contacts, whereas stress of acetic acid and furfural restrict the long-range contacts and significantly change the chromosome organization at domain scales. Further deciphering the domain feature unveils the important transcription factors, Ferric uptake regulator (Fur) proteins, which act as nucleoid-associated proteins to promote long-range (>200 kb) chromosomal communications and regulate the expression of genes involved in stress response. Our work suggests that ubiquitous transcription factors in prokaryotes mediate chromosome organization and regulate stress-resistance genes in bacterial adaptation.
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Affiliation(s)
- Mao Chen
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
- Graduate School of Chinese Academy of Agricultural Sciences; Beijing 100081, PR China
| | - Bo Wu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Yuhuan Huang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
- Graduate School of Chinese Academy of Agricultural Sciences; Beijing 100081, PR China
| | - Weiting Wang
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Yudi Zheng
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
- Graduate School of Chinese Academy of Agricultural Sciences; Beijing 100081, PR China
| | - Samina Shabbir
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Panting Liu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Yonghua Dai
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Mengli Xia
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Guoquan Hu
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
| | - Mingxiong He
- Biomass Energy Technology Research Centre, Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs; Chengdu 610041, PR China
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5
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Tran NT, Le TBK. Control of a gene transfer agent cluster in Caulobacter crescentus by transcriptional activation and anti-termination. Nat Commun 2024; 15:4749. [PMID: 38834569 PMCID: PMC11150451 DOI: 10.1038/s41467-024-49114-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 05/23/2024] [Indexed: 06/06/2024] Open
Abstract
Gene Transfer Agents (GTAs) are phage-like particles that cannot self-multiply and be infectious. Caulobacter crescentus, a bacterium best known as a model organism to study bacterial cell biology and cell cycle regulation, has recently been demonstrated to produce bona fide GTA particles (CcGTA). Since C. crescentus ultimately die to release GTA particles, the production of GTA particles must be tightly regulated and integrated with the host physiology to prevent a collapse in cell population. Two direct activators of the CcGTA biosynthetic gene cluster, GafY and GafZ, have been identified, however, it is unknown how GafYZ controls transcription or how they coordinate gene expression of the CcGTA gene cluster with other accessory genes elsewhere on the genome for complete CcGTA production. Here, we show that the CcGTA gene cluster is transcriptionally co-activated by GafY, integration host factor (IHF), and by GafZ-mediated transcription anti-termination. We present evidence that GafZ is a transcription anti-terminator that likely forms an anti-termination complex with RNA polymerase, NusA, NusG, and NusE to bypass transcription terminators within the 14 kb CcGTA cluster. Overall, we reveal a two-tier regulation that coordinates the synthesis of GTA particles in C. crescentus.
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Affiliation(s)
- Ngat T Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.
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6
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Kopkowski PW, Zhang Z, Saier MH. The effect of DNA-binding proteins on insertion sequence element transposition upstream of the bgl operon in Escherichia coli. Front Microbiol 2024; 15:1388522. [PMID: 38666260 PMCID: PMC11043490 DOI: 10.3389/fmicb.2024.1388522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/22/2024] [Indexed: 04/28/2024] Open
Abstract
The bglGFB operon in Escherichia coli K-12 strain BW25113, encoding the proteins necessary for the uptake and metabolism of β-glucosides, is normally not expressed. Insertion of either IS1 or IS5 upstream of the bgl promoter activates expression of the operon only when the cell is starving in the presence of a β-glucoside, drastically increasing transcription and allowing the cell to survive and grow using this carbon source. Details surrounding the exact mechanism and regulation of the IS insertional event remain unclear. In this work, the role of several DNA-binding proteins in how they affect the rate of insertion upstream of bgl are examined via mutation assays and protocols measuring transcription. Both Crp and IHF exert a positive effect on insertional Bgl+ mutations when present, active, and functional in the cell. Our results characterize IHF's effect in conjunction with other mutations, show that IHF's effect on IS insertion into bgl also affects other operons, and indicate that it may exert its effect by binding to and altering the DNA conformation of IS1 and IS5 in their native locations, rather than by directly influencing transposase gene expression. In contrast, the cAMP-CRP complex acts directly upon the bgl operon by binding upstream of the promoter, presumably altering local DNA into a conformation that enhances IS insertion.
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Affiliation(s)
| | - Zhongge Zhang
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Milton H. Saier
- Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
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7
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Minnick MF. Functional Roles and Genomic Impact of Miniature Inverted-Repeat Transposable Elements (MITEs) in Prokaryotes. Genes (Basel) 2024; 15:328. [PMID: 38540387 PMCID: PMC10969869 DOI: 10.3390/genes15030328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 02/27/2024] [Accepted: 03/01/2024] [Indexed: 06/14/2024] Open
Abstract
Prokaryotic genomes are dynamic tapestries that are strongly influenced by mobile genetic elements (MGEs), including transposons (Tn's), plasmids, and bacteriophages. Of these, miniature inverted-repeat transposable elements (MITEs) are undoubtedly the least studied MGEs in bacteria and archaea. This review explores the diversity and distribution of MITEs in prokaryotes and describes what is known about their functional roles in the host and involvement in genomic plasticity and evolution.
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Affiliation(s)
- Michael F Minnick
- Program in Cellular, Molecular and Microbial Biology, Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
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8
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Graham CI, MacMartin TL, de Kievit TR, Brassinga AKC. Molecular regulation of virulence in Legionella pneumophila. Mol Microbiol 2024; 121:167-195. [PMID: 37908155 DOI: 10.1111/mmi.15172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/15/2023] [Accepted: 09/17/2023] [Indexed: 11/02/2023]
Abstract
Legionella pneumophila is a gram-negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase-like metabolic changes via alternative sigma factors, and two-component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.
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Affiliation(s)
- Christopher I Graham
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teassa L MacMartin
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Teresa R de Kievit
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ann Karen C Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, Manitoba, Canada
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9
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Henneman B, Erkelens AM, Heinsman J, Battjes J, Dame RT. Quantitation of DNA Binding Affinity Using Tethered Particle Motion. Methods Mol Biol 2024; 2819:497-518. [PMID: 39028521 DOI: 10.1007/978-1-0716-3930-6_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The binding constant is an important characteristic of a DNA-binding protein. A large number of methods exist to measure the binding constant, but many of those methods have intrinsic flaws that influence the outcome of the characterization. Tethered particle motion (TPM) is a simple, cheap, and high-throughput single-molecule method that can be used to measure binding constants of proteins binding to DNA reliably, provided that they distort DNA. In TPM, the motion of a bead tethered to a surface by DNA is tracked using light microscopy. A protein binding to the DNA will alter bead motion. This change in bead motion makes it possible to measure the DNA-binding properties of proteins. We use the bacterial protein integration host factor (IHF) and the archaeal histone HMfA as examples to show how specific binding to DNA can be measured. Moreover, we show how the end-to-end distance can provide structural insights into protein-DNA binding.
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Affiliation(s)
- Bram Henneman
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Amanda M Erkelens
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
- Human Genetics, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Joost Heinsman
- Leiden Institute of Physics, Leiden University, Leiden, The Netherlands
| | - Julius Battjes
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Remus T Dame
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands.
- Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands.
- Centre for Interdisciplinary Genome Research, Leiden University, Leiden, The Netherlands.
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10
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Norris V, Kayser C, Muskhelishvili G, Konto-Ghiorghi Y. The roles of nucleoid-associated proteins and topoisomerases in chromosome structure, strand segregation, and the generation of phenotypic heterogeneity in bacteria. FEMS Microbiol Rev 2023; 47:fuac049. [PMID: 36549664 DOI: 10.1093/femsre/fuac049] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/06/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022] Open
Abstract
How to adapt to a changing environment is a fundamental, recurrent problem confronting cells. One solution is for cells to organize their constituents into a limited number of spatially extended, functionally relevant, macromolecular assemblies or hyperstructures, and then to segregate these hyperstructures asymmetrically into daughter cells. This asymmetric segregation becomes a particularly powerful way of generating a coherent phenotypic diversity when the segregation of certain hyperstructures is with only one of the parental DNA strands and when this pattern of segregation continues over successive generations. Candidate hyperstructures for such asymmetric segregation in prokaryotes include those containing the nucleoid-associated proteins (NAPs) and the topoisomerases. Another solution to the problem of creating a coherent phenotypic diversity is by creating a growth-environment-dependent gradient of supercoiling generated along the replication origin-to-terminus axis of the bacterial chromosome. This gradient is modulated by transcription, NAPs, and topoisomerases. Here, we focus primarily on two topoisomerases, TopoIV and DNA gyrase in Escherichia coli, on three of its NAPs (H-NS, HU, and IHF), and on the single-stranded binding protein, SSB. We propose that the combination of supercoiling-gradient-dependent and strand-segregation-dependent topoisomerase activities result in significant differences in the supercoiling of daughter chromosomes, and hence in the phenotypes of daughter cells.
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Affiliation(s)
- Vic Norris
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Clara Kayser
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
| | - Georgi Muskhelishvili
- Agricultural University of Georgia, School of Natural Sciences, 0159 Tbilisi, Georgia
| | - Yoan Konto-Ghiorghi
- University of Rouen, Laboratory of Bacterial Communication and Anti-infection Strategies, EA 4312, 76821 Mont Saint Aignan, France
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11
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Morrison JJ, Banas DA, Madden EK, DiBiasio EC, Rowley DC, Cohen PS, Camberg JL. Metabolic flux regulates growth transitions and antibiotic tolerance in uropathogenic Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540013. [PMID: 37215002 PMCID: PMC10197701 DOI: 10.1101/2023.05.09.540013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Reducing growth and limiting metabolism are strategies that allow bacteria to survive exposure to environmental stress and antibiotics. During infection, uropathogenic Escherichia coli (UPEC) may enter a quiescent state that enables them to reemerge after completion of successful antibiotic treatment. Many clinical isolates, including the well characterized UPEC strain CFT073, also enter a metabolite-dependent, quiescent state in vitro that is reversible with cues, including peptidoglycan-derived peptides and amino acids. Here, we show that quiescent UPEC is antibiotic tolerant and demonstrate that metabolic flux in the tricarboxylic acid (TCA) cycle regulates the UPEC quiescent state via succinyl-CoA. We also demonstrate that the transcriptional regulator complex IHF and the FtsZ-interacting protein ZapE, which is important for E. coli division during stress, are essential for UPEC to enter the quiescent state. Notably, in addition to engaging FtsZ and late-stage cell division proteins, ZapE also interacts directly with TCA cycle enzymes in bacterial two hybrid assays. We report direct interactions between succinate dehydrogenase complex subunit SdhC, the late-stage cell division protein FtsN, and ZapE. These interactions likely enable communication between oxidative metabolism and the cell division machinery in UPEC. Moreover, these interactions are conserved in an E. coli K-12 strain. This work suggests that there is coordination among the two fundamental and essential pathways that regulate overall growth, quiescence, and antibiotic susceptibility.
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Affiliation(s)
- Josiah J. Morrison
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, RI, 02881
| | - Daniel A. Banas
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, RI, 02881
| | - Ellen K. Madden
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, RI, 02881
| | - Eric C. DiBiasio
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, RI, 02881
| | - David C. Rowley
- Department of Biomedical & Pharmaceutical Sciences, The University of Rhode Island, Kingston, RI, 02881
| | - Paul S. Cohen
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, RI, 02881
| | - Jodi L. Camberg
- Department of Cell & Molecular Biology, The University of Rhode Island, Kingston, RI, 02881
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12
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Sinorhizobium meliloti integration host factor (IHF) genes affect symbiotic performance of alfalfa ( Medicago sativa L.). Acta Biochim Biophys Sin (Shanghai) 2022; 54:1390-1393. [PMID: 35983973 PMCID: PMC9827912 DOI: 10.3724/abbs.2022110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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13
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Pozdeev G, Beckett MC, Mogre A, Thomson NR, Dorman CJ. Reciprocally rewiring and repositioning the Integration Host Factor (IHF) subunit genes in Salmonella enterica serovar Typhimurium: impacts on physiology and virulence. Microb Genom 2022; 8. [PMID: 35166652 PMCID: PMC8942017 DOI: 10.1099/mgen.0.000768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The Integration Host Factor (IHF) is a heterodimeric nucleoid-associated protein that plays roles in bacterial nucleoid architecture and genome-wide gene regulation. The ihfA and ihfB genes encode the subunits and are located 350 kbp apart, in the Right replichore of the Salmonella chromosome. IHF is composed of one IhfA and one IhfB subunit. Despite this 1 : 1 stoichiometry, MS revealed that IhfB is produced in 2-fold excess over IhfA. We re-engineered Salmonella to exchange reciprocally the protein-coding regions of ihfA and ihfB, such that each relocated protein-encoding region was driven by the expression signals of the other's gene. MS showed that in this 'rewired' strain, IhfA is produced in excess over IhfB, correlating with enhanced stability of the hybrid ihfB-ihfA mRNA that was expressed from the ihfB promoter. Nevertheless, the rewired strain grew at a similar rate to the wild-type and was similar in competitive fitness. However, compared to the wild-type, it was less motile, had growth-phase-specific reductions in SPI-1 and SPI-2 gene expression, and was engulfed at a higher rate by RAW macrophage. Our data show that while exchanging the physical locations of its ihf genes and the rewiring of their regulatory circuitry are well tolerated in Salmonella, genes involved in the production of type 3 secretion systems exhibit dysregulation accompanied by altered phenotypes.
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Affiliation(s)
- German Pozdeev
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Michael C Beckett
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Aalap Mogre
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
| | | | - Charles J Dorman
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
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14
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Dugar G, Hofmann A, Heermann DW, Hamoen LW. A chromosomal loop anchor mediates bacterial genome organization. Nat Genet 2022; 54:194-201. [PMID: 35075232 DOI: 10.1038/s41588-021-00988-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 11/19/2021] [Indexed: 12/22/2022]
Abstract
Nucleoprotein complexes play an integral role in genome organization of both eukaryotes and prokaryotes. Apart from their role in locally structuring and compacting DNA, several complexes are known to influence global organization by mediating long-range anchored chromosomal loop formation leading to spatial segregation of large sections of DNA. Such megabase-range interactions are ubiquitous in eukaryotes, but have not been demonstrated in prokaryotes. Here, using a genome-wide sedimentation-based approach, we found that a transcription factor, Rok, forms large nucleoprotein complexes in the bacterium Bacillus subtilis. Using chromosome conformation capture and live-imaging of DNA loci, we show that these complexes robustly interact with each other over large distances. Importantly, these Rok-dependent long-range interactions lead to anchored chromosomal loop formation, thereby spatially isolating large sections of DNA, as previously observed for insulator proteins in eukaryotes.
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Affiliation(s)
- Gaurav Dugar
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands.
| | - Andreas Hofmann
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
| | - Dieter W Heermann
- Institute for Theoretical Physics, Heidelberg University, Heidelberg, Germany
| | - Leendert W Hamoen
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, the Netherlands.
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15
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Adler BA, Kazakov AE, Zhong C, Liu H, Kutter E, Lui LM, Nielsen TN, Carion H, Deutschbauer AM, Mutalik VK, Arkin AP. The genetic basis of phage susceptibility, cross-resistance and host-range in Salmonella. MICROBIOLOGY (READING, ENGLAND) 2021; 167. [PMID: 34910616 PMCID: PMC8744999 DOI: 10.1099/mic.0.001126] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Though bacteriophages (phages) are known to play a crucial role in bacterial fitness and virulence, our knowledge about the genetic basis of their interaction, cross-resistance and host-range is sparse. Here, we employed genome-wide screens in Salmonella enterica serovar Typhimurium to discover host determinants involved in resistance to eleven diverse lytic phages including four new phages isolated from a therapeutic phage cocktail. We uncovered 301 diverse host factors essential in phage infection, many of which are shared between multiple phages demonstrating potential cross-resistance mechanisms. We validate many of these novel findings and uncover the intricate interplay between RpoS, the virulence-associated general stress response sigma factor and RpoN, the nitrogen starvation sigma factor in phage cross-resistance. Finally, the infectivity pattern of eleven phages across a panel of 23 genome sequenced Salmonella strains indicates that additional constraints and interactions beyond the host factors uncovered here define the phage host range.
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Affiliation(s)
- Benjamin A Adler
- The UC Berkeley-UCSF Graduate Program in Bioengineering, Berkeley, California, USA.,Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.,Innovative Genomics Institute, University of California, Berkeley, California, USA
| | - Alexey E Kazakov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Crystal Zhong
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Hualan Liu
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | | | - Lauren M Lui
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Torben N Nielsen
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Heloise Carion
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Vivek K Mutalik
- Innovative Genomics Institute, University of California, Berkeley, California, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam P Arkin
- Department of Bioengineering, University of California, Berkeley, Berkeley, California, USA.,Innovative Genomics Institute, University of California, Berkeley, California, USA.,Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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16
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Bennett RK, Gregory GJ, Gonzalez JE, Har JRG, Antoniewicz MR, Papoutsakis ET. Improving the Methanol Tolerance of an Escherichia coli Methylotroph via Adaptive Laboratory Evolution Enhances Synthetic Methanol Utilization. Front Microbiol 2021; 12:638426. [PMID: 33643274 PMCID: PMC7904680 DOI: 10.3389/fmicb.2021.638426] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 01/21/2021] [Indexed: 02/05/2023] Open
Abstract
There is great interest in developing synthetic methylotrophs that harbor methane and methanol utilization pathways in heterologous hosts such as Escherichia coli for industrial bioconversion of one-carbon compounds. While there are recent reports that describe the successful engineering of synthetic methylotrophs, additional efforts are required to achieve the robust methylotrophic phenotypes required for industrial realization. Here, we address an important issue of synthetic methylotrophy in E. coli: methanol toxicity. Both methanol, and its oxidation product, formaldehyde, are cytotoxic to cells. Methanol alters the fluidity and biological properties of cellular membranes while formaldehyde reacts readily with proteins and nucleic acids. Thus, efforts to enhance the methanol tolerance of synthetic methylotrophs are important. Here, adaptive laboratory evolution was performed to improve the methanol tolerance of several E. coli strains, both methylotrophic and non-methylotrophic. Serial batch passaging in rich medium containing toxic methanol concentrations yielded clones exhibiting improved methanol tolerance. In several cases, these evolved clones exhibited a > 50% improvement in growth rate and biomass yield in the presence of high methanol concentrations compared to the respective parental strains. Importantly, one evolved clone exhibited a two to threefold improvement in the methanol utilization phenotype, as determined via 13C-labeling, at non-toxic, industrially relevant methanol concentrations compared to the respective parental strain. Whole genome sequencing was performed to identify causative mutations contributing to methanol tolerance. Common mutations were identified in 30S ribosomal subunit proteins, which increased translational accuracy and provided insight into a novel methanol tolerance mechanism. This study addresses an important issue of synthetic methylotrophy in E. coli and provides insight as to how methanol toxicity can be alleviated via enhancing methanol tolerance. Coupled improvement of methanol tolerance and synthetic methanol utilization is an important advancement for the field of synthetic methylotrophy.
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Affiliation(s)
- R Kyle Bennett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States.,Molecular Biotechnology Laboratory, The Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
| | - Gwendolyn J Gregory
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States.,Molecular Biotechnology Laboratory, The Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
| | - Jacqueline E Gonzalez
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Jie Ren Gerald Har
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, United States.,Molecular Biotechnology Laboratory, The Delaware Biotechnology Institute, University of Delaware, Newark, DE, United States
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17
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Reverchon S, Meyer S, Forquet R, Hommais F, Muskhelishvili G, Nasser W. The nucleoid-associated protein IHF acts as a 'transcriptional domainin' protein coordinating the bacterial virulence traits with global transcription. Nucleic Acids Res 2021; 49:776-790. [PMID: 33337488 PMCID: PMC7826290 DOI: 10.1093/nar/gkaa1227] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/30/2020] [Accepted: 12/07/2020] [Indexed: 02/04/2023] Open
Abstract
Bacterial pathogenic growth requires a swift coordination of pathogenicity function with various kinds of environmental stress encountered in the course of host infection. Among the factors critical for bacterial adaptation are changes of DNA topology and binding effects of nucleoid-associated proteins transducing the environmental signals to the chromosome and coordinating the global transcriptional response to stress. In this study, we use the model phytopathogen Dickeya dadantii to analyse the organisation of transcription by the nucleoid-associated heterodimeric protein IHF. We inactivated the IHFα subunit of IHF thus precluding the IHFαβ heterodimer formation and determined both phenotypic effects of ihfA mutation on D. dadantii virulence and the transcriptional response under various conditions of growth. We show that ihfA mutation reorganises the genomic expression by modulating the distribution of chromosomal DNA supercoils at different length scales, thus affecting many virulence genes involved in both symptomatic and asymptomatic phases of infection, including those required for pectin catabolism. Altogether, we propose that IHF heterodimer is a 'transcriptional domainin' protein, the lack of which impairs the spatiotemporal organisation of transcriptional stress-response domains harbouring various virulence traits, thus abrogating the pathogenicity of D. dadantii.
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Affiliation(s)
- Sylvie Reverchon
- Univ Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240 MAP, F-69622, France
| | - Sam Meyer
- Univ Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240 MAP, F-69622, France
| | - Raphaël Forquet
- Univ Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240 MAP, F-69622, France
| | - Florence Hommais
- Univ Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240 MAP, F-69622, France
| | - Georgi Muskhelishvili
- Agricultural University of Georgia, School of Natural Sciences, 0159 Tbilisi, Georgia
| | - William Nasser
- Univ Lyon, Université Claude Bernard Lyon 1, INSA-Lyon, CNRS, UMR5240 MAP, F-69622, France
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18
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Kyle Bennett R, Agee A, Har JRG, von Hagel B, Antoniewicz MR, Papoutsakis ET. Regulatory interventions improve the biosynthesis of limiting amino acids from methanol carbon to improve synthetic methylotrophy in Escherichia coli. Biotechnol Bioeng 2020; 118:43-57. [PMID: 32876943 DOI: 10.1002/bit.27549] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/29/2020] [Accepted: 08/26/2020] [Indexed: 12/30/2022]
Abstract
Synthetic methylotrophy aims to engineer methane and methanol utilization pathways in platform hosts like Escherichia coli for industrial bioprocessing of natural gas and biogas. While recent attempts to engineer synthetic methylotrophs have proved successful, autonomous methylotrophy, that is, the ability to utilize methane or methanol as sole carbon and energy substrates, has not yet been realized. Here, we address an important limitation of autonomous methylotrophy in E. coli: the inability of the organism to synthesize several amino acids when grown on methanol. We targeted global and local amino acid regulatory networks. Those include removal of amino acid allosteric feedback inhibition (argAH15Y , ilvAL447F , hisGE271K , leuAG462D , proBD107N , thrAS345F , trpES40F ), knockouts of transcriptional repressors (ihfA, metJ); and overexpression of amino acid biosynthetic operons (hisGDCBHAFI, leuABCD, thrABC, trpEDCBA) and transcriptional regulators (crp, purR). Compared to the parent methylotrophic E. coli strain that was unable to synthesize these amino acids from methanol carbon, these strategies resulted in improved biosynthesis of limiting proteinogenic amino acids (histidine, leucine, lysine, methionine, phenylalanine, threonine, tyrosine) from methanol carbon. In several cases, improved amino acid biosynthesis from methanol carbon led to improvements in methylotrophic growth in methanol minimal medium supplemented with a small amount of yeast extract. This study addresses a key limitation currently preventing autonomous methylotrophy in E. coli and possibly other synthetic methylotrophs and provides insight as to how this limitation can be alleviated via global and local regulatory modifications.
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Affiliation(s)
- Robert Kyle Bennett
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Alec Agee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Jie R G Har
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Bryan von Hagel
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,The Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
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19
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Hognon C, Garaude S, Timmins J, Chipot C, Dehez F, Monari A. Molecular Bases of DNA Packaging in Bacteria Revealed by All-Atom Molecular Dynamics Simulations: The Case of Histone-Like Proteins in Borrelia burgdorferi. J Phys Chem Lett 2019; 10:7200-7207. [PMID: 31693374 DOI: 10.1021/acs.jpclett.9b02978] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
DNA compaction is essential to ensure the packaging of the genetic material in living cells and also plays a key role in the epigenetic regulation of gene expression. In both humans and bacteria, DNA packaging is achieved by specific well-conserved proteins. Here, by means of all-atom molecular dynamics simulations, including the determination of relevant free-energy profiles, we rationalize the molecular bases for this remarkable process in bacteria, illustrating the crucial role played by positively charged amino acids of a small histone-like protein. We also present compelling evidence that this histone-like protein alone can induce strong bending of a DNA duplex around its core domain, a process that requires overcoming a major free-energy barrier.
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Affiliation(s)
- Cécilia Hognon
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
| | - Simon Garaude
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
| | - Joanna Timmins
- Université Grenoble Alpes , CNRS, CEA, IBS , F-38000 Grenoble , France
| | - Christophe Chipot
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
- Department of Physics , University of Illinois at Urbana-Champaign , 1110 West Green Street , Urbana , Illinois 61801 , United States
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign , 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - François Dehez
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign , 54506 Vandoeuvre-lès-Nancy Cedex, France
| | - Antonio Monari
- Université de Lorraine and CNRS, LPCT UMR 7019 , F-54000 Nancy , France
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20
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Ge ZH, Long QS, Yuan PB, Pan X, Shen D, Lu YJ. The Temporal Expression of Global Regulator Protein CsrA Is Dually Regulated by ClpP During the Biphasic Life Cycle of Legionella pneumophila. Front Microbiol 2019; 10:2495. [PMID: 31787938 PMCID: PMC6853998 DOI: 10.3389/fmicb.2019.02495] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/16/2019] [Indexed: 11/16/2022] Open
Abstract
Legionella pneumophila, an environmental bacterium that parasitizes protozoa, is the causative pathogen of Legionnaires' disease. L. pneumophila adopts a distinct biphasic life cycle that allows it to adapt to environmental conditions for survival, replication, and transmission. This cycle consists of a non-virulent replicative phase (RP) and a virulent transmissive phase (TP). Timely and fine-tuned expression of growth and virulence factors in a life cycle-dependent manner is crucial. Herein, we report evidence that CsrA, a key regulator of the switch between the RP and the TP, is dually regulated in a ClpP-dependent manner during the biphasic life cycle of L. pneumophila. First, we show that the protein level of CsrA is temporal during the life cycle and is degraded by ClpP during the TP. The ectopic expression of CsrA in a ΔclpP mutant, but not in the wild type, inhibits both the initiation of the RP in vitro and the invasiveness to Acanthamoeba castellanii, indicating that the ClpP-mediated proteolytic pathway regulates the CsrA protein level. We further show that the temporally expressed IHFB is the transcriptional inhibitor of csrA and is degraded via a ClpP-dependent manner during the RP. During the RP, the level of CsrA is increased by promoting the degradation of IHFB and reducing the degradation of the accumulated CsrA via a ClpP-dependent manner. During the TP, the level of CsrA is decreased by inhibiting the degradation of IHFB and promoting the degradation of the accumulated CsrA via a ClpP-dependent manner as well. In conclusion, our results show that the growth-stage-specific expression level of CsrA is dually regulated by ClpP-dependent proteolysis at both the transcription and protein levels during the biphasic life cycle of L. pneumophila.
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Affiliation(s)
- Zhen-Huang Ge
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Biomedical Center, Sun Yat-sen University, Guangzhou, China
| | - Qin-Sha Long
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Biomedical Center, Sun Yat-sen University, Guangzhou, China
| | - Pei-Bo Yuan
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Biomedical Center, Sun Yat-sen University, Guangzhou, China
| | - Xin Pan
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Dong Shen
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Biomedical Center, Sun Yat-sen University, Guangzhou, China
| | - Yong-Jun Lu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Biomedical Center, Sun Yat-sen University, Guangzhou, China
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21
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Integration Host Factor IHF facilitates homologous recombination and mutagenic processes in Pseudomonas putida. DNA Repair (Amst) 2019; 85:102745. [PMID: 31715424 DOI: 10.1016/j.dnarep.2019.102745] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/25/2019] [Accepted: 10/31/2019] [Indexed: 12/14/2022]
Abstract
Nucleoid-associated proteins (NAPs) such as IHF, HU, Fis, and H-NS alter the topology of bound DNA and may thereby affect accessibility of DNA to repair and recombination processes. To examine this possibility, we investigated the effect of IHF on the frequency of homologous recombination (HR) and point mutations in soil bacterium Pseudomonas putida by using plasmidial and chromosomal assays. We observed positive effect of IHF on the frequency of HR, whereas this effect varied depending both on the chromosomal location of the HR target and the type of plasmid used in the assay. The occurrence of point mutations in plasmid was also facilitated by IHF, whereas in the chromosome the positive effect of IHF appeared only at certain DNA sequences and/or chromosomal positions. We did not observe any significant effects of IHF on the spectrum of mutations. However, despite of the presence or absence of IHF, different mutational hot spots appeared both in plasmid and in chromosome. Additionally, the frequency of frameshift mutations in the chromosome was also strongly affected by the location of the mutational target sequence. Taking together, our results indicate that IHF facilitates the occurrence of genetic changes in P. putida, whereas the location of the target sequence affects both the IHF-dependent and IHF-independent mechanisms.
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22
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Wen Q, Liu XJ, Zhu WC, Li L, Li MY, Peng XX, Li H. Characterization of balofloxacin-stressed proteomics and identification of balofloxacin-binding proteins pre-peptidase and integration host factor in Edwardsiella tarda. J Proteomics 2019; 205:103413. [DOI: 10.1016/j.jprot.2019.103413] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/23/2019] [Accepted: 06/06/2019] [Indexed: 12/13/2022]
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23
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Flores-Ríos R, Quatrini R, Loyola A. Endogenous and Foreign Nucleoid-Associated Proteins of Bacteria: Occurrence, Interactions and Effects on Mobile Genetic Elements and Host's Biology. Comput Struct Biotechnol J 2019; 17:746-756. [PMID: 31303979 PMCID: PMC6606824 DOI: 10.1016/j.csbj.2019.06.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/05/2019] [Accepted: 06/11/2019] [Indexed: 02/08/2023] Open
Abstract
Mobile Genetic Elements (MGEs) are mosaics of functional gene modules of diverse evolutionary origin and are generally divergent from the hosts´ genetic background. Existing biases in base composition and codon usage of these elements` genes impose transcription and translation limitations that may affect the physical and regulatory integration of MGEs in new hosts. Stable appropriation of the foreign DNA depends on a number of host factors among which are the Nucleoid-Associated Proteins (NAPs). These small, basic, highly abundant proteins bind and bend DNA, altering its topology and folding, thereby affecting all known essential DNA metabolism related processes. Both chromosomally- (endogenous) and MGE- (foreign) encoded NAPs have been shown to exist in bacteria. While the role of host-encoded NAPs in xenogeneic silencing of both episomal (plasmids) and integrative MGEs (pathogenicity islands and prophages) is well acknowledged, less is known about the role of MGE-encoded NAPs in the foreign elements biology or their influence on the host's chromosome expression dynamics. Here we review existing literature on the topic, present examples on the positive and negative effects that endogenous and foreign NAPs exert on global transcriptional gene expression, MGE integrative and excisive recombination dynamics, persistence and transfer to suitable hosts and discuss the nature and relevance of synergistic and antagonizing higher order interactions between diverse types of NAPs.
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Affiliation(s)
| | - Raquel Quatrini
- Fundación Ciencia y Vida, Avenida Zañartu 1482, Ñuñoa, Santiago, Chile.,Millennium Nucleus in the Biology of Intestinal Microbiota, Santiago, Chile
| | - Alejandra Loyola
- Fundación Ciencia y Vida, Avenida Zañartu 1482, Ñuñoa, Santiago, Chile
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24
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Plateau P, Moch C, Blanquet S. Spermidine strongly increases the fidelity of Escherichia coli CRISPR Cas1-Cas2 integrase. J Biol Chem 2019; 294:11311-11322. [PMID: 31171718 DOI: 10.1074/jbc.ra119.007619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 06/03/2019] [Indexed: 12/20/2022] Open
Abstract
Site-selective CRISPR array expansion at the origin of bacterial adaptive immunity relies on recognition of sequence-dependent DNA structures by the conserved Cas1-Cas2 integrase. Off-target integration of a new spacer sequence outside canonical CRISPR arrays has been described in vitro However, this nonspecific integration activity is rare in vivo Here, we designed gel assays to monitor fluorescently labeled protospacer insertion in a supercoiled 3-kb plasmid harboring a minimal CRISPR locus derived from the Escherichia coli type I-E system. This assay enabled us to distinguish and quantify target and off-target insertion events catalyzed by E. coli Cas1-Cas2 integrase. We show that addition of the ubiquitous polyamine spermidine or of another polyamine, spermine, significantly alters the ratio between target and off-target insertions. Notably, addition of 2 mm spermidine quenched the off-target spacer insertion rate by a factor of 20-fold, and, in the presence of integration host factor, spermidine also increased insertion at the CRISPR locus 1.5-fold. The observation made in our in vitro system that spermidine strongly decreases nonspecific activity of Cas1-Cas2 integrase outside the leader-proximal region of a CRISPR array suggests that this polyamine plays a potential role in the fidelity of the spacer integration also in vivo.
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Affiliation(s)
- Pierre Plateau
- BIOC, CNRS, Ecole polytechnique, IP Paris, F-91128 Palaiseau, France
| | - Clara Moch
- BIOC, CNRS, Ecole polytechnique, IP Paris, F-91128 Palaiseau, France
| | - Sylvain Blanquet
- BIOC, CNRS, Ecole polytechnique, IP Paris, F-91128 Palaiseau, France
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25
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Henneman B, Heinsman J, Battjes J, Dame RT. Quantitation of DNA-Binding Affinity Using Tethered Particle Motion. Methods Mol Biol 2019; 1837:257-275. [PMID: 30109615 DOI: 10.1007/978-1-4939-8675-0_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The binding constant is an important characteristic of a DNA-binding protein. A large number of methods exist to measure the binding constant, but many of those methods have intrinsic flaws that influence the outcome of the characterization. Tethered Particle Motion (TPM) is a simple, cheap, and high-throughput single-molecule method that can be used to reliably measure binding constants of proteins binding to DNA, provided that they distort DNA. In TPM, the motion of a bead tethered to a surface by DNA is tracked using light microscopy. A protein binding to the DNA will alter bead motion. This makes it possible to measure binding properties. We use the bacterial protein Integration Host Factor (IHF) as an example to show how specific binding to DNA can be measured. Moreover, we show a new intuitive quantitative approach to displaying data obtained via TPM.
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Affiliation(s)
- Bram Henneman
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Joost Heinsman
- Leiden Institute of Physics, Leiden University, Leiden, The Netherlands
| | - Julius Battjes
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Remus T Dame
- Leiden Institute of Chemistry and Centre for Microbial Cell Biology, Leiden University, Leiden, The Netherlands.
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Charlier D, Nguyen Le Minh P, Roovers M. Regulation of carbamoylphosphate synthesis in Escherichia coli: an amazing metabolite at the crossroad of arginine and pyrimidine biosynthesis. Amino Acids 2018; 50:1647-1661. [PMID: 30238253 PMCID: PMC6245113 DOI: 10.1007/s00726-018-2654-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 09/11/2018] [Indexed: 12/17/2022]
Abstract
In all organisms, carbamoylphosphate (CP) is a precursor common to the synthesis of arginine and pyrimidines. In Escherichia coli and most other Gram-negative bacteria, CP is produced by a single enzyme, carbamoylphosphate synthase (CPSase), encoded by the carAB operon. This particular situation poses a question of basic physiological interest: what are the metabolic controls coordinating the synthesis and distribution of this high-energy substance in view of the needs of both pathways? The study of the mechanisms has revealed unexpected moonlighting gene regulatory activities of enzymes and functional links between mechanisms as diverse as gene regulation and site-specific DNA recombination. At the level of enzyme production, various regulatory mechanisms were found to cooperate in a particularly intricate transcriptional control of a pair of tandem promoters. Transcription initiation is modulated by an interplay of several allosteric DNA-binding transcription factors using effector molecules from three different pathways (arginine, pyrimidines, purines), nucleoid-associated factors (NAPs), trigger enzymes (enzymes with a second unlinked gene regulatory function), DNA remodeling (bending and wrapping), UTP-dependent reiterative transcription initiation, and stringent control by the alarmone ppGpp. At the enzyme level, CPSase activity is tightly controlled by allosteric effectors originating from different pathways: an inhibitor (UMP) and two activators (ornithine and IMP) that antagonize the inhibitory effect of UMP. Furthermore, it is worth noticing that all reaction intermediates in the production of CP are extremely reactive and unstable, and protected by tunneling through a 96 Å long internal channel.
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Affiliation(s)
- Daniel Charlier
- Research Group of Microbiology, Department of Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
| | - Phu Nguyen Le Minh
- Research Group of Microbiology, Department of Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium
| | - Martine Roovers
- LABIRIS Institut de Recherches, Av. Emile Gryson 1, 1070, Brussels, Belgium
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Bartholomae M, Buivydas A, Viel JH, Montalbán-López M, Kuipers OP. Major gene-regulatory mechanisms operating in ribosomally synthesized and post-translationally modified peptide (RiPP) biosynthesis. Mol Microbiol 2017; 106:186-206. [DOI: 10.1111/mmi.13764] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/02/2017] [Accepted: 08/03/2017] [Indexed: 02/06/2023]
Affiliation(s)
- Maike Bartholomae
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
| | - Andrius Buivydas
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
| | - Jakob H. Viel
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
| | - Manuel Montalbán-López
- Department of Microbiology; University of Granada, C. Fuentenueva s/n; 18071 Granada Spain
| | - Oscar P. Kuipers
- Department of Molecular Genetics; University of Groningen, Nijenborgh 7; 9747AG Groningen The Netherlands
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Sánchez DG, Primo ED, Damiani MT, Lisa AT. Pseudomonas aeruginosa gbdR gene is transcribed from a σ54-dependent promoter under the control of NtrC/CbrB, IHF and BetI. MICROBIOLOGY-SGM 2017; 163:1343-1354. [PMID: 28791946 DOI: 10.1099/mic.0.000502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Pseudomonasaeruginosa uses choline as a source of carbon and nitrogen, and also for the synthesis of glycine betaine, an osmoprotectant under stress conditions such as drought and salinity. The transcription factor GbdR is the specific regulator of choline metabolism and it belongs to the Arac/XylS family of transcriptional regulators. Despite the link between choline catabolism and bacterial pathogenicity, gbdR regulation has not been explored in detail. In the present work, we describe how gbdR transcription can be initiated from a σ54-dependent promoter. gbdR transcription can be activated by NtrC in the absence of a preferential nitrogen source, by CbrB in the absence of a preferential carbon source, and by the integration host factor favouring DNA bending. In addition, we found that BetI negatively regulates gbdR expression in the absence of choline. We identified two overlapping BetI binding sites in the gbdR promoter sequence, providing an additional example of σ54-promoter down-regulation. Based on our findings, we propose a model for gdbR regulation and its impact on choline metabolism.
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Affiliation(s)
- Diego Germán Sánchez
- Laboratory of Phagocytosis and Intracellular Transport, School of Medicine, University of Cuyo, IHEM-CONICET, Mendoza 5500, Argentina.,Department of Molecular Biology, FCEFQN, National University of Río Cuarto, Route 36-Km 601, 5800, Argentina
| | - Emiliano David Primo
- Department of Molecular Biology, FCEFQN, National University of Río Cuarto, Route 36-Km 601, 5800, Argentina
| | - María Teresa Damiani
- Laboratory of Phagocytosis and Intracellular Transport, School of Medicine, University of Cuyo, IHEM-CONICET, Mendoza 5500, Argentina
| | - Angela Teresita Lisa
- Department of Molecular Biology, FCEFQN, National University of Río Cuarto, Route 36-Km 601, 5800, Argentina
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29
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Affiliation(s)
- Yasuko YANAGIDA
- Laboratory for Feature Interdisiplinary Research of Science and Technology (FIRST), Institute of Innovative Research (IIR), Tokyo Institute of Technology
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30
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Abstract
The site-specific recombinase encoded by bacteriophage λ (Int) is responsible for integrating and excising the viral chromosome into and out of the chromosome of its Escherichia coli host. Int carries out a reaction that is highly directional, tightly regulated, and depends upon an ensemble of accessory DNA bending proteins acting on 240 bp of DNA encoding 16 protein binding sites. This additional complexity enables two pathways, integrative and excisive recombination, whose opposite, and effectively irreversible, directions are dictated by different physiological and environmental signals. Int recombinase is a heterobivalent DNA binding protein and each of the four Int protomers, within a multiprotein 400 kDa recombinogenic complex, is thought to bind and, with the aid of DNA bending proteins, bridge one arm- and one core-type DNA site. In the 12 years since the publication of the last review focused solely on the λ site-specific recombination pathway in Mobile DNA II, there has been a great deal of progress in elucidating the molecular details of this pathway. The most dramatic advances in our understanding of the reaction have been in the area of X-ray crystallography where protein-DNA structures have now been determined for of all of the DNA-protein interfaces driving the Int pathway. Building on this foundation of structures, it has been possible to derive models for the assembly of components that determine the regulatory apparatus in the P-arm, and for the overall architectures that define excisive and integrative recombinogenic complexes. The most fundamental additional mechanistic insights derive from the application of hexapeptide inhibitors and single molecule kinetics.
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31
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Dame RT, Tark-Dame M. Bacterial chromatin: converging views at different scales. Curr Opin Cell Biol 2016; 40:60-65. [PMID: 26942688 DOI: 10.1016/j.ceb.2016.02.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/04/2016] [Accepted: 02/14/2016] [Indexed: 01/13/2023]
Abstract
Bacterial genomes are functionally organized and compactly folded into a structure referred to as bacterial chromatin or the nucleoid. An important role in genome folding is attributed to Nucleoid-Associated Proteins, also referred to as bacterial chromatin proteins. Although a lot of molecular insight in the mechanisms of operation of these proteins has been generated in the test tube, knowledge on genome organization in the cellular context is still lagging behind severely. Here, we discuss important advances in the understanding of three-dimensional genome organization due to the application of Chromosome Conformation Capture and super-resolution microscopy techniques. We focus on bacterial chromatin proteins whose proposed role in genome organization is supported by these approaches. Moreover, we discuss recent insights into the interrelationship between genome organization and genome activity/stability in bacteria.
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Affiliation(s)
- Remus T Dame
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Leiden, The Netherlands.
| | - Mariliis Tark-Dame
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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Rao H, Damian MS, Alshiekh A, Elmroth SKC, Diederichsen U. Design, synthesis and DNA interactions of a chimera between a platinum complex and an IHF mimicking peptide. Org Biomol Chem 2015; 13:11704-13. [PMID: 26477860 DOI: 10.1039/c5ob01885d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conjugation of metal complexes with peptide scaffolds possessing high DNA binding affinity has shown to modulate their biological activities and to enhance their interaction with DNA. In this work, a platinum complex/peptide chimera was synthesized based on a model of the Integration Host Factor (IHF), an architectural protein possessing sequence specific DNA binding and bending abilities through its interaction with a minor groove. The model peptide consists of a cyclic unit resembling the minor grove binding subdomain of IHF, a positively charged lysine dendrimer for electrostatic interactions with the DNA phosphate backbone and a flexible glycine linker tethering the two units. A norvaline derived artificial amino acid was designed to contain a dimethylethylenediamine as a bidentate platinum chelating unit, and introduced into the IHF mimicking peptides. The interaction of the chimeric peptides with various DNA sequences was studied by utilizing the following experiments: thermal melting studies, agarose gel electrophoresis for plasmid DNA unwinding experiments, and native and denaturing gel electrophoresis to visualize non-covalent and covalent peptide-DNA adducts, respectively. By incorporation of the platinum metal center within the model peptide mimicking IHF we have attempted to improve its specificity and DNA targeting ability, particularly towards those sequences containing adjacent guanine residues.
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Affiliation(s)
- Harita Rao
- Institut für Organische und Biomolekulare Chemie, Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany.
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Zere TR, Vakulskas CA, Leng Y, Pannuri A, Potts AH, Dias R, Tang D, Kolaczkowski B, Georgellis D, Ahmer BMM, Romeo T. Genomic Targets and Features of BarA-UvrY (-SirA) Signal Transduction Systems. PLoS One 2015; 10:e0145035. [PMID: 26673755 PMCID: PMC4682653 DOI: 10.1371/journal.pone.0145035] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/30/2015] [Indexed: 11/30/2022] Open
Abstract
The two-component signal transduction system BarA-UvrY of Escherichia coli and its orthologs globally regulate metabolism, motility, biofilm formation, stress resistance, virulence of pathogens and quorum sensing by activating the transcription of genes for regulatory sRNAs, e.g. CsrB and CsrC in E. coli. These sRNAs act by sequestering the RNA binding protein CsrA (RsmA) away from lower affinity mRNA targets. In this study, we used ChIP-exo to identify, at single nucleotide resolution, genomic sites for UvrY (SirA) binding in E. coli and Salmonella enterica. The csrB and csrC genes were the strongest targets of crosslinking, which required UvrY phosphorylation by the BarA sensor kinase. Crosslinking occurred at two sites, an inverted repeat sequence far upstream of the promoter and a site near the -35 sequence. DNAse I footprinting revealed specific binding of UvrY in vitro only to the upstream site, indicative of additional binding requirements and/or indirect binding to the downstream site. Additional genes, including cspA, encoding the cold-shock RNA-binding protein CspA, showed weaker crosslinking and modest or negligible regulation by UvrY. We conclude that the global effects of UvrY/SirA on gene expression are primarily mediated by activating csrB and csrC transcription. We also used in vivo crosslinking and other experimental approaches to reveal new features of csrB/csrC regulation by the DeaD and SrmB RNA helicases, IHF, ppGpp and DksA. Finally, the phylogenetic distribution of BarA-UvrY was analyzed and found to be uniquely characteristic of γ-Proteobacteria and strongly anti-correlated with fliW, which encodes a protein that binds to CsrA and antagonizes its activity in Bacillus subtilis. We propose that BarA-UvrY and orthologous TCS transcribe sRNA antagonists of CsrA throughout the γ-Proteobacteria, but rarely or never perform this function in other species.
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Affiliation(s)
- Tesfalem R. Zere
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Christopher A. Vakulskas
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Yuanyuan Leng
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Archana Pannuri
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Anastasia H. Potts
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Raquel Dias
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Dongjie Tang
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Bryan Kolaczkowski
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
| | - Dimitris Georgellis
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México D.F., México
| | - Brian M. M. Ahmer
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States of America
| | - Tony Romeo
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, United States of America
- * E-mail:
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34
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Ray S, Banerjee A. Molecular level biodegradation of phenol and its derivatives through dmp operon of Pseudomonas putida: A bio-molecular modeling and docking analysis. J Environ Sci (China) 2015; 36:144-151. [PMID: 26456616 DOI: 10.1016/j.jes.2015.03.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/05/2015] [Accepted: 03/31/2015] [Indexed: 06/05/2023]
Abstract
Participation of Pseudomonas putida-derived methyl phenol (dmp) operon and DmpR protein in the biodegradation of phenol or other harmful, organic, toxic pollutants was investigated at a molecular level. Documentation documents that P. putida has DmpR protein which positively regulates dmp operon in the presence of inducers; like phenols. From the operon, phenol hydroxylase encoded by dmpN gene, participates in degrading phenols after dmp operon is expressed. For the purpose, the 3-D models of the four domains from DmpR protein and of the DNA sequences from the two Upstream Activation Sequences (UAS) present at the promoter region of the operon were demonstrated using discrete molecular modeling techniques. The best modeled structures satisfying their stereo-chemical properties were selected in each of the cases. To stabilize the individual structures, energy optimization was performed. In the presence of inducers, probable interactions among domains and then the two independent DNA structures with the fourth domain were perused by manifold molecular docking simulations. The complex structures were made to be stable by minimizing their overall energy. Responsible amino acid residues, nucleotide bases and binding patterns for the biodegradation, were examined. In the presence of the inducers, the biodegradation process is initiated by the interaction of phe50 from the first protein domain with the inducers. Only after the interaction of the last domain with the DNA sequences individually, the operon is expressed. This novel residue level study is paramount for initiating transcription in the operon; thereby leading to expression of phenol hydroxylase followed by phenol biodegradation.
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Affiliation(s)
- Sujay Ray
- Department of Biochemistry and Biophysics, University of Kalyani, Kalyani, 741245 Nadia, West Bengal, India; Department of Biotechnology, Bengal College of Engineering and Technology, Shahid Sukumar Sarani, Bidhannagar, Durgapur-713212, West Bengal, India.
| | - Arundhati Banerjee
- Department of Biotechnology, National Institute of Technology, Mahatma Gandhi Avenue, Durgapur 713209, West Bengal, India.
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35
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Ramisetty SK, Dias RS. Synergistic role of DNA-binding protein and macromolecular crowding on DNA condensation. An experimental and theoretical approach. J Mol Liq 2015. [DOI: 10.1016/j.molliq.2015.04.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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36
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Talukder A, Ishihama A. Growth phase dependent changes in the structure and protein composition of nucleoid in Escherichia coli. SCIENCE CHINA-LIFE SCIENCES 2015. [PMID: 26208826 DOI: 10.1007/s11427-015-4898-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The genomic DNA of bacteria is highly compacted in a single or a few bodies known as nucleoids. Here, we have isolated Escherichia coli nucleoid by sucrose density gradient centrifugation. The sedimentation rates, structures as well as protein/ DNA composition of isolated nucleoids were then compared under various growth phases. The nucleoid structures were found to undergo changes during the cell growth; i. e., the nucleoid structure in the stationary phase was more tightly compacted than that in the exponential phase. In addition to factor for inversion stimulation (Fis), histone-like nucleoid structuring protein (H-NS), heat-unstable nucleoid protein (HU) and integration host factor (IHF) here we have identified, three new candidates of E. coli nucleoid, namely DNA-binding protein from starved cells (Dps), host factor for phage Qβ (Hfq) and suppressor of td(-) phenotype A (StpA). Our results reveal that the major components of exponential phase nucleoid are Fis, HU, H-NS, StpA and Hfq, while Dps occupies more than half of the stationary phase nucleoid. It has been known for a while that Dps is the main nucleoid-associated protein at stationary phase. From these results and the prevailing information, we propose a model for growth phase dependent changes in the structure and protein composition of nucleoid in E. coli.
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Affiliation(s)
- AliAzam Talukder
- Department of Microbiology, Jahangirnagar University, Dhaka, 1342, Bangladesh. .,Micro-Nano Technology Research Center, Hosei University, Tokyo, 184-0003, Japan.
| | - Akira Ishihama
- Department of Molecular Genetics, National Institute of Genetics, Shizuoka, 411-8540, Japan.,Micro-Nano Technology Research Center, Hosei University, Tokyo, 184-0003, Japan
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Connolly JPR, Goldstone RJ, Burgess K, Cogdell RJ, Beatson SA, Vollmer W, Smith DGE, Roe AJ. The host metabolite D-serine contributes to bacterial niche specificity through gene selection. ISME JOURNAL 2015; 9:1039-51. [PMID: 25526369 PMCID: PMC4366372 DOI: 10.1038/ismej.2014.242] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/07/2014] [Accepted: 11/13/2014] [Indexed: 01/29/2023]
Abstract
Escherichia coli comprise a diverse array of both commensals and niche-specific pathotypes. The ability to cause disease results from both carriage of specific virulence factors and regulatory control of these via environmental stimuli. Moreover, host metabolites further refine the response of bacteria to their environment and can dramatically affect the outcome of the host-pathogen interaction. Here, we demonstrate that the host metabolite, D-serine, selectively affects gene expression in E. coli O157:H7. Transcriptomic profiling showed exposure to D-serine results in activation of the SOS response and suppresses expression of the Type 3 Secretion System (T3SS) used to attach to host cells. We also show that concurrent carriage of both the D-serine tolerance locus (dsdCXA) and the locus of enterocyte effacement pathogenicity island encoding a T3SS is extremely rare, a genotype that we attribute to an 'evolutionary incompatibility' between the two loci. This study demonstrates the importance of co-operation between both core and pathogenic genetic elements in defining niche specificity.
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Affiliation(s)
- James P R Connolly
- 1] Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK [2] School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Robert J Goldstone
- 1] Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK [2] School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Karl Burgess
- 1] Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK [2] School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Richard J Cogdell
- Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, UK
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, University of Queensland, St Lucia, Queensland, Australia
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - David G E Smith
- 1] Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK [2] School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK [3] Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, UK
| | - Andrew J Roe
- 1] Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK [2] School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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38
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Evolutionary expansion of a regulatory network by counter-silencing. Nat Commun 2014; 5:5270. [PMID: 25348042 PMCID: PMC4215172 DOI: 10.1038/ncomms6270] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 09/15/2014] [Indexed: 11/09/2022] Open
Abstract
Horizontal gene transfer plays a major role in bacterial evolution. Successful acquisition of new genes requires their incorporation into existing regulatory networks. This study compares the regulation of conserved genes in the PhoPQ regulon of Salmonella enterica serovar Typhimurium with that of PhoPQ-regulated horizontally-acquired genes, which are silenced by the histone-like protein H-NS. We demonstrate that PhoP up-regulates conserved and horizontally-acquired genes by distinct mechanisms. Conserved genes are regulated by classical PhoP-mediated activation and are invariant in promoter architecture, whereas horizontally-acquired genes exhibit variable promoter architecture and are regulated by PhoP-mediated counter-silencing. Biochemical analyses show that a horizontally-acquired promoter adopts different structures in the silenced and counter-silenced states, implicating the remodeling of the H-NS nucleoprotein filament and the subsequent restoration of open complex formation as the central mechanism of counter-silencing. Our results indicate that counter-silencing is favored in the regulatory integration of newly-acquired genes because it is able to accommodate multiple promoter architectures.
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39
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Poza-Carrión C, Jiménez-Vicente E, Navarro-Rodríguez M, Echavarri-Erasun C, Rubio LM. Kinetics of Nif gene expression in a nitrogen-fixing bacterium. J Bacteriol 2014; 196:595-603. [PMID: 24244007 DOI: 10.1128/jb.11942-13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
Nitrogen fixation is a tightly regulated trait. Switching from N2 fixation-repressing conditions to the N2-fixing state is carefully controlled in diazotrophic bacteria mainly because of the high energy demand that it imposes. By using quantitative real-time PCR and quantitative immunoblotting, we show here how nitrogen fixation (nif) gene expression develops in Azotobacter vinelandii upon derepression. Transient expression of the transcriptional activator-encoding gene, nifA, was followed by subsequent, longer-duration waves of expression of the nitrogenase biosynthetic and structural genes. Importantly, expression timing, expression levels, and NifA dependence varied greatly among the nif operons. Moreover, the exact concentrations of Nif proteins and their changes over time were determined for the first time. Nif protein concentrations were exquisitely balanced, with FeMo cofactor biosynthetic proteins accumulating at levels 50- to 100-fold lower than those of the structural proteins. Mutants lacking nitrogenase structural genes or impaired in FeMo cofactor biosynthesis showed overenhanced responses to derepression that were proportional to the degree of nitrogenase activity impairment, consistent with the existence of at least two negative-feedback regulatory mechanisms. The first such mechanism responded to the levels of fixed nitrogen, whereas the second mechanism appeared to respond to the levels of the mature NifDK component. Altogether, these findings provide a framework to engineer N2 fixation in nondiazotrophs.
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Affiliation(s)
- César Poza-Carrión
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Madrid, Spain
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40
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Abstract
Nitrogen fixation is a tightly regulated trait. Switching from N2 fixation-repressing conditions to the N2-fixing state is carefully controlled in diazotrophic bacteria mainly because of the high energy demand that it imposes. By using quantitative real-time PCR and quantitative immunoblotting, we show here how nitrogen fixation (nif) gene expression develops in Azotobacter vinelandii upon derepression. Transient expression of the transcriptional activator-encoding gene, nifA, was followed by subsequent, longer-duration waves of expression of the nitrogenase biosynthetic and structural genes. Importantly, expression timing, expression levels, and NifA dependence varied greatly among the nif operons. Moreover, the exact concentrations of Nif proteins and their changes over time were determined for the first time. Nif protein concentrations were exquisitely balanced, with FeMo cofactor biosynthetic proteins accumulating at levels 50- to 100-fold lower than those of the structural proteins. Mutants lacking nitrogenase structural genes or impaired in FeMo cofactor biosynthesis showed overenhanced responses to derepression that were proportional to the degree of nitrogenase activity impairment, consistent with the existence of at least two negative-feedback regulatory mechanisms. The first such mechanism responded to the levels of fixed nitrogen, whereas the second mechanism appeared to respond to the levels of the mature NifDK component. Altogether, these findings provide a framework to engineer N2 fixation in nondiazotrophs.
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41
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In silico identification and experimental characterization of regulatory elements controlling the expression of the Salmonella csrB and csrC genes. J Bacteriol 2013; 196:325-36. [PMID: 24187088 DOI: 10.1128/jb.00806-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The small RNAs CsrB and CsrC of Salmonella indirectly control the expression of numerous genes encoding widespread cellular functions, including virulence. The expression of csrB and csrC genes, which are located in different chromosomal regions, is coordinated by positive transcriptional control mediated by the two-component regulatory system BarA/SirA. Here, we identified by computational analysis an 18-bp inverted repeat (IR) sequence located far upstream from the promoter of Salmonella enterica serovar Typhimurium csrB and csrC genes. Deletion analysis and site-directed mutagenesis of the csrB and csrC regulatory regions revealed that this IR sequence is required for transcriptional activation of both genes. Protein-DNA and protein-protein interaction assays showed that the response regulator SirA specifically binds to the IR sequence and provide evidence that SirA acts as a dimer. Interestingly, whereas the IR sequence was essential for the SirA-mediated expression of csrB, our results revealed that SirA controls the expression of csrC not only by binding to the IR sequence but also by an indirect mode involving the Csr system. Additional computational, biochemical, and genetic analyses demonstrated that the integration host factor (IHF) global regulator positively controls the expression of csrB, but not of csrC, by interacting with a sequence located between the promoter and the SirA-binding site. These findings contribute to the better understanding of the regulatory mechanism controlling the expression of CsrB and CsrC.
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Salmonella enterica serovar Typhimurium skills to succeed in the host: virulence and regulation. Clin Microbiol Rev 2013; 26:308-41. [PMID: 23554419 DOI: 10.1128/cmr.00066-12] [Citation(s) in RCA: 455] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Salmonella enterica serovar Typhimurium is a primary enteric pathogen infecting both humans and animals. Infection begins with the ingestion of contaminated food or water so that salmonellae reach the intestinal epithelium and trigger gastrointestinal disease. In some patients the infection spreads upon invasion of the intestinal epithelium, internalization within phagocytes, and subsequent dissemination. In that case, antimicrobial therapy, based on fluoroquinolones and expanded-spectrum cephalosporins as the current drugs of choice, is indicated. To accomplish the pathogenic process, the Salmonella chromosome comprises several virulence mechanisms. The most important virulence genes are those located within the so-called Salmonella pathogenicity islands (SPIs). Thus far, five SPIs have been reported to have a major contribution to pathogenesis. Nonetheless, further virulence traits, such as the pSLT virulence plasmid, adhesins, flagella, and biofilm-related proteins, also contribute to success within the host. Several regulatory mechanisms which synchronize all these elements in order to guarantee bacterial survival have been described. These mechanisms govern the transitions from the different pathogenic stages and drive the pathogen to achieve maximal efficiency inside the host. This review focuses primarily on the virulence armamentarium of this pathogen and the extremely complicated regulatory network controlling its success.
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Zhu H, Sandiford SK, van Wezel GP. Triggers and cues that activate antibiotic production by actinomycetes. J Ind Microbiol Biotechnol 2013; 41:371-86. [PMID: 23907251 DOI: 10.1007/s10295-013-1309-z] [Citation(s) in RCA: 140] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 06/30/2013] [Indexed: 12/24/2022]
Abstract
Actinomycetes are a rich source of natural products, and these mycelial bacteria produce the majority of the known antibiotics. The increasing difficulty to find new drugs via high-throughput screening has led to a decline in antibiotic research, while infectious diseases associated with multidrug resistance are spreading rapidly. Here we review new approaches and ideas that are currently being developed to increase our chances of finding novel antimicrobials, with focus on genetic, chemical, and ecological methods to elicit the expression of biosynthetic gene clusters. The genome sequencing revolution identified numerous gene clusters for natural products in actinomycetes, associated with a potentially huge reservoir of unknown molecules, and prioritizing them is a major challenge for in silico screening-based approaches. Some antibiotics are likely only expressed under very specific conditions, such as interaction with other microbes, which explains the renewed interest in soil and marine ecology. The identification of new gene clusters, as well as chemical elicitors and culturing conditions that activate their expression, should allow scientists to reinforce their efforts to find the necessary novel antimicrobial drugs.
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Affiliation(s)
- Hua Zhu
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE, Leiden, The Netherlands
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Rathor N, Chandolia A, Saini NK, Sinha R, Pathak R, Garima K, Singh S, Varma-Basil M, Bose M. An insight into the regulation of mce4 operon of Mycobacterium tuberculosis. Tuberculosis (Edinb) 2013; 93:389-97. [PMID: 23622789 DOI: 10.1016/j.tube.2013.03.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/19/2013] [Accepted: 03/30/2013] [Indexed: 01/21/2023]
Abstract
The mce4 operon is reported to be involved in cholesterol utilization and intracellular survival of Mycobacterium tuberculosis (M. tuberculosis). The regulatory mechanism of this important operon was unknown so far. Here we report detection of the promoter region and regulatory factors of the mce4 operon. The in silico analyzed putative promoter region was cloned in promoter selection vector and promoter strength was measured by O-Nitrophenyl-β-D-galactopyranosidase (ONPG) assay. The transcription start site was determined by 5' Rapid amplification of C terminal end (5'RACE). Surface stress, hypoxia and presence of cholesterol, were found to be stimulatory for mce4 operon promoter induction. Pull down assay coupled with 2D gel electrophoresis resolved many proteins; few prominent spots were processed for identification. MALDI TOF-TOF identified proteins of M. tuberculosis which supported the regulatory function of the identified promoter region and cholesterol utilization of mce4 operon. Since mce4 operon is involved in cholesterol utilization and intracellular survival of M. tuberculosis in the later phase of infection, identification of the promoter sequence as reported in the present communication may facilitate development of effective inhibitors to regulate expression of mce4 operon which may prove to be a good drug target to prevent latency in tuberculosis.
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Affiliation(s)
- Nisha Rathor
- Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India.
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Mlc is a transcriptional activator with a key role in integrating cyclic AMP receptor protein and integration host factor regulation of leukotoxin RNA synthesis in Aggregatibacter actinomycetemcomitans. J Bacteriol 2013; 195:2284-97. [PMID: 23475968 DOI: 10.1128/jb.02144-12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans, a periodontal pathogen, synthesizes leukotoxin (LtxA), a protein that helps the bacterium evade the host immune response. Transcription of the ltxA operon is induced during anaerobic growth. The cyclic AMP (cAMP) receptor protein (CRP) indirectly increases ltxA expression, but the intermediary regulator is unknown. Integration host factor (IHF) binds to and represses the leukotoxin promoter, but neither CRP nor IHF is responsible for the anaerobic induction of ltxA RNA synthesis. Thus, we have undertaken studies to identify other regulators of leukotoxin transcription and to demonstrate how these proteins work together to modulate leukotoxin synthesis. First, analyses of ltxA RNA expression from defined leukotoxin promoter mutations in the chromosome identify positions -69 to -35 as the key control region and indicate that an activator protein modulates leukotoxin transcription. We show that Mlc, which is a repressor in Escherichia coli, functions as a direct transcriptional activator in A. actinomycetemcomitans; an mlc deletion mutant reduces leukotoxin RNA synthesis, and recombinant Mlc protein binds specifically at the -68 to -40 region of the leukotoxin promoter. Furthermore, we show that CRP activates ltxA expression indirectly by increasing the levels of Mlc. Analyses of Δmlc, Δihf, and Δihf Δmlc strains demonstrate that Mlc can increase RNA polymerase (RNAP) activity directly and that IHF represses ltxA RNA synthesis mainly by blocking Mlc binding. Finally, a Δihf Δmlc mutant still induces ltxA during anaerobic growth, indicating that there are additional factors involved in leukotoxin transcriptional regulation. A model for the coordinated regulation of leukotoxin transcription is presented.
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Pitre CAJ, Tanner JR, Patel P, Brassinga AKC. Regulatory control of temporally expressed integration host factor (IHF) in Legionella pneumophila. Microbiology (Reading) 2013; 159:475-492. [DOI: 10.1099/mic.0.062117-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Chantalle A. J. Pitre
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Jennifer R. Tanner
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Palak Patel
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ann Karen C. Brassinga
- Department of Microbiology, Faculty of Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Regulation, integrase-dependent excision, and horizontal transfer of genomic islands in Legionella pneumophila. J Bacteriol 2013; 195:1583-97. [PMID: 23354744 DOI: 10.1128/jb.01739-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Legionella pneumophila is a Gram-negative freshwater agent which multiplies in specialized nutrient-rich vacuoles of amoebae. When replicating in human alveolar macrophages, Legionella can cause Legionnaires' disease. Recently, we identified a new type of conjugation/type IVA secretion system (T4ASS) in L. pneumophila Corby (named trb-tra). Analogous versions of trb-tra are localized on the genomic islands Trb-1 and Trb-2. Both can exist as an episomal circular form, and Trb-1 can be transferred horizontally to other Legionella strains by conjugation. In our current work, we discovered the importance of a site-specific integrase (Int-1, lpc2818) for the excision and conjugation process of Trb-1. Furthermore, we identified the genes lvrRABC (lpc2813 to lpc2816) to be involved in the regulation of Trb-1 excision. In addition, we demonstrated for the first time that a Legionella genomic island (LGI) of L. pneumophila Corby (LpcGI-2) encodes a functional type IV secretion system. The island can be transferred horizontally by conjugation and is integrated site specifically into the genome of the transconjugants. LpcGI-2 generates three different episomal forms. The predominant episomal form, form A, is generated integrase dependently (Lpc1833) and transferred by conjugation in a pilT-dependent manner. Therefore, the genomic islands Trb-1 and LpcGI-2 should be classified as integrative and conjugative elements (ICEs). Coculture studies of L. pneumophila wild-type and mutant strains revealed that the int-1 and lvrRABC genes (located on Trb-1) as well as lpc1833 and pilT (located on LpcGI-2) do not influence the in vivo fitness of L. pneumophila in Acanthamoeba castellanii.
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Jakimowicz D, van Wezel GP. Cell division and DNA segregation in Streptomyces: how to build a septum in the middle of nowhere? Mol Microbiol 2012; 85:393-404. [PMID: 22646484 DOI: 10.1111/j.1365-2958.2012.08107.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Streptomycetes are antibiotic-producing filamentous microorganisms that have a mycelial life style. In many ways streptomycetes are the odd ones out in terms of cell division. While the basic components of the cell division machinery are similar to those found in rod-shaped bacteria such as Escherichia coli and Bacillus subtilis, many aspects of the control of cell division and its co-ordination with chromosome segregation are remarkably different. The rather astonishing fact that cell division is not essential for growth makes these bacteria unique. The fundamental difference between the cross-walls produced during normal growth and sporulation septa formed in aerial hyphae, and the role of the divisome in their formation are discussed. We then take a closer look at the way septum site localization is regulated in the long and multinucleoid Streptomyces hyphae, with particular focus on actinomycete-specific proteins and the role of nucleoid segregation and condensation.
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Prieto AI, Kahramanoglou C, Ali RM, Fraser GM, Seshasayee ASN, Luscombe NM. Genomic analysis of DNA binding and gene regulation by homologous nucleoid-associated proteins IHF and HU in Escherichia coli K12. Nucleic Acids Res 2012; 40:3524-37. [PMID: 22180530 PMCID: PMC3333857 DOI: 10.1093/nar/gkr1236] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 11/24/2011] [Accepted: 11/28/2011] [Indexed: 11/18/2022] Open
Abstract
IHF and HU are two heterodimeric nucleoid-associated proteins (NAP) that belong to the same protein family but interact differently with the DNA. IHF is a sequence-specific DNA-binding protein that bends the DNA by over 160°. HU is the most conserved NAP, which binds non-specifically to duplex DNA with a particular preference for targeting nicked and bent DNA. Despite their importance, the in vivo interactions of the two proteins to the DNA remain to be described at a high resolution and on a genome-wide scale. Further, the effects of these proteins on gene expression on a global scale remain contentious. Finally, the contrast between the functions of the homo- and heterodimeric forms of proteins deserves the attention of further study. Here we present a genome-scale study of HU- and IHF binding to the Escherichia coli K12 chromosome using ChIP-seq. We also perform microarray analysis of gene expression in single- and double-deletion mutants of each protein to identify their regulons. The sequence-specific binding profile of IHF encompasses ∼30% of all operons, though the expression of <10% of these is affected by its deletion suggesting combinatorial control or a molecular backup. The binding profile for HU is reflective of relatively non-specific binding to the chromosome, however, with a preference for A/T-rich DNA. The HU regulon comprises highly conserved genes including those that are essential and possibly supercoiling sensitive. Finally, by performing ChIP-seq experiments, where possible, of each subunit of IHF and HU in the absence of the other subunit, we define genome-wide maps of DNA binding of the proteins in their hetero- and homodimeric forms.
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Affiliation(s)
- Ana I. Prieto
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK, Centre for Biotechnology, Anna University, Chennai 600 035, National Centre for Biological Sciences, GKVK, Bellary Road, Bangalore 560 065, India and Okinawa Institute of Science and Technology, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Christina Kahramanoglou
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK, Centre for Biotechnology, Anna University, Chennai 600 035, National Centre for Biological Sciences, GKVK, Bellary Road, Bangalore 560 065, India and Okinawa Institute of Science and Technology, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Ruhi M. Ali
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK, Centre for Biotechnology, Anna University, Chennai 600 035, National Centre for Biological Sciences, GKVK, Bellary Road, Bangalore 560 065, India and Okinawa Institute of Science and Technology, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Gillian M. Fraser
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK, Centre for Biotechnology, Anna University, Chennai 600 035, National Centre for Biological Sciences, GKVK, Bellary Road, Bangalore 560 065, India and Okinawa Institute of Science and Technology, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Aswin S. N. Seshasayee
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK, Centre for Biotechnology, Anna University, Chennai 600 035, National Centre for Biological Sciences, GKVK, Bellary Road, Bangalore 560 065, India and Okinawa Institute of Science and Technology, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Nicholas M. Luscombe
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, MRC-National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK, Centre for Biotechnology, Anna University, Chennai 600 035, National Centre for Biological Sciences, GKVK, Bellary Road, Bangalore 560 065, India and Okinawa Institute of Science and Technology, Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
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