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Chatterjee A. Mycobacterium tuberculosis and its secreted tyrosine phosphatases. Biochimie 2023; 212:41-47. [PMID: 37059349 DOI: 10.1016/j.biochi.2023.04.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/04/2023] [Accepted: 04/12/2023] [Indexed: 04/16/2023]
Abstract
Tuberculosis is one of the most common infectious diseases and has been a major burden for a long time now. Increasing drug resistance in TB is slowing down the process of disease treatment. Mycobacterium tuberculosis, the causative agent of TB is known to have a cascade of virulence factors to fight with host's immune system. The phosphatases (PTPs) of Mtb plays a critical role as these are secretory in nature and help the survival of bacteria in host. Researchers have been trying to synthesize inhibitors against a lot of virulence factors of Mtb but recently the phosphatases have gained a lot of interest due to their secretory nature. This review gives a concise overview of virulence factors of Mtb with emphasis on mPTPs. Here we discuss the current scenario of drug development against mPTPs.
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Affiliation(s)
- Aditi Chatterjee
- University of Maryland Greenebaum Comprehensive Cancer Center, Baltimore, MD, USA.
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2
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Mahatha AC, Banerjee SK, Ghosh A, Lata S, Saha S, Basu J, Kundu M. A systems approach to decipher a role of transcription factor RegX3 in the adaptation of Mycobacterium tuberculosis to hypoxic stress. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35980355 DOI: 10.1099/mic.0.001229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two-component systems (TCSs) are required for the ability of Mycobacterium tuberculosis to respond to stress. The paired TCS, SenX3-RegX3 is known to respond to phosphate starvation and acid stress. The other stress conditions under which RegX3 is required for M. tuberculosis to mount an appropriate response, remain incompletely understood. Here we have employed genome-wide microarray profiling to compare gene expression in a ΔregX3 mutant with the wild-type under phosphate stress, in order to gain information on the probable RegX3 regulon. We pulled out a set of 128 hypoxia-associated genes, which could potentially be regulated by RegX3, by overlapping the gene set downregulated at least twofold in ΔregX3 with the gene set reported in the literature to be associated with the response to hypoxia. We identified potential RegX3 binding inverted repeats at the loci of 41 of these genes, in silico. We also observed that ΔregX3 was attenuated in terms of its ability to withstand hypoxia, and this was reversed upon complementation with regX3, corroborating a role of RegX3 in the response of M. tuberculosis to hypoxia. We validated the binding of RegX3 at the upstream regions of a selected set of these genes. Electrophoretic mobility shift assays (EMSAs) confirmed that RegX3 binds to the upstream regions of the hypoxia-associated genes Rv3334, whiB7, Rv0195, Rv0196 and Rv1960c. Gene expression analyses showed that the expression of these genes is regulated by RegX3 under hypoxia. We also show that the expression of whiB7, Rv3334 and Rv0195 in macrophage-grown M. tuberculosis, is dependent on RegX3. Finally, we show that attenuation of survival of ΔregX3 under hypoxia is partly reversed upon overexpression of either Rv0195 or Rv3334, suggesting that the RegX3-Rv0195 and the RegX3-Rv3334 axis are involved in the adaptation of M. tuberculosis to a hypoxic environment.
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Affiliation(s)
- Amar Chandra Mahatha
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Srijon Kaushik Banerjee
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India.,Present address: Department of Microbiology and Molecular Genetics, School of Medicine, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA 15217, USA
| | - Abhirupa Ghosh
- Division of Bioinformatics, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Suruchi Lata
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Sudipto Saha
- Division of Bioinformatics, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Joyoti Basu
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Manikuntala Kundu
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
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Xu Y, You D, Ye BC. RegX3 Controls Glyoxylate Shunt and Mycobacteria Survival by Directly Regulating the Transcription of Isocitrate Lyase Gene in Mycobacterium smegmatis. ACS Infect Dis 2021; 7:927-936. [PMID: 33663204 DOI: 10.1021/acsinfecdis.1c00067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The glyoxylate shunt is a pathway associated with the assimilation of fatty acids and is implicated in the resistance of M. tuberculosis (Mtb). Isocitrate lyase (ICL), the first enzyme in the glyoxylate shunt, mediates Mtb infections and its survival in mice via fatty acids, metabolism, and physiological functions. Here, we found that in Mycobacterium smegmatis (M. smegmatis) the two-component system SenX3-RegX3 regulated the glyoxylate shunt in response to phosphate starvation by controlling the transcription of icl. In response to phosphate availability, the phosphate regulator RegX3 directly bound to the upstream regulatory region of icl and repressed its transcription. The inactivation of regX3 increased icl transcription and ICL activity, causing a growth defect in M. smegmatis with fatty acids as the sole source of carbon and energy. The growth defect was partly due to the toxicity of the excess glyoxylate produced by ICL. A decrease in glyoxylic acid levels, overexpression of regX3, or the chemical inhibition (IA or 3-NP) of ICL restored the growth of the Regx3-deficient M. smegmatis. Thus, we established a genetic network between the phosphate stress response and glyoxylate shunt based on the amount of intracellular ICL during mycobacterial survival on short-chain fatty acids, which contributed to its antimicrobial arsenal.
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Affiliation(s)
- Ya Xu
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Di You
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Bang-Ce Ye
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
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Pei JF, Qi N, Li YX, Wo J, Ye BC. RegX3-Mediated Regulation of Methylcitrate Cycle in Mycobacterium smegmatis. Front Microbiol 2021; 12:619387. [PMID: 33603724 PMCID: PMC7884335 DOI: 10.3389/fmicb.2021.619387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 01/13/2021] [Indexed: 11/16/2022] Open
Abstract
Mycobacterium tuberculosis is a global human pathogen that infects macrophages and can establish a latent infection. Emerging evidence has established the nutrients metabolism as a key point to study the pathogenesis of M. tuberculosis and host immunity. It was reported that fatty acids and cholesterol are the major nutrient sources of M. tuberculosis in the period of infection. However, the mechanism by which M. tuberculosis utilizes lipids for maintaining life activities in nutrient-deficiency macrophages is poorly understood. Mycobacterium smegmatis is fast-growing and generally used to study its pathogenic counterpart, M. tuberculosis. In this work, we found that the phosphate sensing regulator RegX3 of M. smegmatis is required for its growing on propionate and surviving in macrophages. We further demonstrated that the expression of prpR and related genes (prpDBC) in methylcitrate cycle could be enhanced by RegX3 in response to the phosphate-starvation condition. The binding sites of the promoter region of prpR for RegX3 and PrpR were investigated. In addition, cell morphology assay showed that RegX3 is responsible for cell morphological elongation, thus promoting the proliferation and survival of M. smegmatis in macrophages. Taken together, our findings revealed a novel transcriptional regulation mechanism of RegX3 on propionate metabolism, and uncovered that the nutrients-sensing regulatory system puts bacteria at metabolic steady state by altering cell morphology. More importantly, since we observed that M. tuberculosis RegX3 also binds to the prpR operon in vitro, the RegX3-mediated regulation might be general in M. tuberculosis and other mycobacteria for nutrient sensing and environmental adaptation.
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Affiliation(s)
- Jin-Feng Pei
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Nan Qi
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Yu-Xin Li
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Jing Wo
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China
| | - Bang-Ce Ye
- Institute of Engineering Biology and Health, Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China.,Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
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5
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Sousa EH, Carepo MS, Moura JJ. Nitrate-nitrite fate and oxygen sensing in dormant Mycobacterium tuberculosis: A bioinorganic approach highlighting the importance of transition metals. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Mavi PS, Singh S, Kumar A. Reductive Stress: New Insights in Physiology and Drug Tolerance of Mycobacterium. Antioxid Redox Signal 2020; 32:1348-1366. [PMID: 31621379 DOI: 10.1089/ars.2019.7867] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Significance:Mycobacterium tuberculosis (Mtb) encounters reductive stress during its infection cycle. Notably, host-generated protective responses, such as acidic pH inside phagosomes and lysosomes, exposure to glutathione in alveolar hypophase (i.e., a thin liquid lining consisting of surfactant and proteins in the alveolus), and hypoxic environments inside granulomas are associated with the accumulation of reduced cofactors, such as nicotinamide adenine dinucleotide (reduced form), nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide (reduced form), and nonprotein thiols (e.g., mycothiol), leading to reductive stress in Mtb cells. Dissipation of this reductive stress is important for survival of the bacterium. If reductive stress is not dissipated, it leads to generation of reactive oxygen species, which may be fatal for the cells. Recent Advances: This review focuses on mechanisms utilized by mycobacteria to sense and respond to reductive stress. Importantly, exposure of Mtb cells to reductive stress leads to growth inhibition, altered metabolism, modulation of virulence, and drug tolerance. Mtb is equipped with thiol buffering systems of mycothiol and ergothioneine to protect itself from various redox stresses. These systems are complemented by thioredoxin and thioredoxin reductase (TR) systems for maintaining cellular redox homeostasis. A diverse array of sensors is used by Mycobacterium for monitoring its intracellular redox status. Upon sensing reductive stress, Mtb uses a flexible and robust metabolic system for its dissipation. Branched electron transport chain allows Mycobacterium to function with different terminal electron acceptors and modulate proton motive force to fulfill energy requirements under diverse scenarios. Interestingly, Mtb utilizes variations in the tricarboxylic cycle and a number of dehydrogenases to dissipate reductive stress. Upon prolonged exposure to reductive stress, Mtb utilizes biosynthesis of storage and virulence lipids as a dissipative mechanism. Critical Issues: The mechanisms utilized by Mycobacterium for sensing and tackling reductive stress are not well characterized. Future Directions: The precise role of thiol buffering and TR systems in neutralizing reductive stress is not well defined. Genetic systems that respond to metabolic reductive stress and thiol reductive stress need to be mapped. Genetic screens could aid in identification of such systems. Given that management of reductive stress is critical for both actively replicating and persister mycobacteria, an improved understanding of the mechanisms used by mycobacteria for dissipation of reductive stress may lead to identification of vulnerable choke points that could be targeted for killing Mtb in vivo.
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Affiliation(s)
- Parminder Singh Mavi
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Shweta Singh
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Ashwani Kumar
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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Park EJ, Kwon YM, Lee JW, Kang HY, Oh JI. Dual control of RegX3 transcriptional activity by SenX3 and PknB. J Biol Chem 2019; 294:11023-11034. [PMID: 31160336 DOI: 10.1074/jbc.ra119.008232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/30/2019] [Indexed: 01/08/2023] Open
Abstract
The mycobacterial SenX3-RegX3 two-component system consists of the SenX3 sensor histidine kinase and its cognate RegX3 response regulator. This system is a phosphorelay-based regulatory system involved in sensing environmental Pi levels and induction of genes required for Pi acquisition under Pi-limiting conditions. Here we demonstrate that overexpression of the kinase domain of Mycobacterium tuberculosis PknB (PknB-KDMtb) inhibits the transcriptional activity of RegX3 of both M. tuberculosis and Mycobacterium smegmatis (RegX3Mtb and RegX3Ms, respectively). Mass spectrometry results, along with those of in vitro phosphorylation and complementation analyses, revealed that PknB kinase activity inhibits the transcriptional activity of RegX3Mtb through phosphorylation events at Thr-100, Thr-191, and Thr-217. Electrophoretic mobility shift assays disclosed that phosphorylation of Thr-191 and Thr-217 abolishes the DNA-binding ability of RegX3Mtb and that Thr-100 phosphorylation likely prevents RegX3Mtb from being activated through conformational changes induced by SenX3-mediated phosphorylation. We propose that the convergence of the PknB and SenX3-RegX3 signaling pathways might enable mycobacteria to integrate environmental Pi signals with the cellular replication state to adjust gene expression in response to Pi availability.
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Affiliation(s)
- Eun-Jin Park
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
| | - Yu-Mi Kwon
- Biomedical Research Institute, Center for Theragnosis, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea, and; Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Jin-Won Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Ho-Young Kang
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
| | - Jeong-Il Oh
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea,.
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8
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Li X, Lv X, Lin Y, Zhen J, Ruan C, Duan W, Li Y, Xie J. Role of two-component regulatory systems in intracellular survival of Mycobacterium tuberculosis. J Cell Biochem 2019; 120:12197-12207. [PMID: 31026098 DOI: 10.1002/jcb.28792] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/11/2019] [Accepted: 01/14/2019] [Indexed: 11/06/2022]
Abstract
The typical two-component regulatory systems (TCSs), consisting of response regulator and histidine kinase, play a central role in survival of pathogenic bacteria under stress conditions such as nutrient starvation, hypoxia, and nitrosative stress. A total of 11 complete paired two-component regulatory systems have been found in Mycobacterium tuberculosis, including a few isolated kinase and regulatory genes. Increasing evidence has shown that TCSs are closely associated with multiple physiological process like intracellular persistence, pathogenicity, and metabolism. This review gives the two-component signal transduction systems in M. tuberculosis and their signal transduction roles in adaption to the environment.
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Affiliation(s)
- Xue Li
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Xi Lv
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Yanping Lin
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Junfeng Zhen
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Cao Ruan
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Wei Duan
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Yue Li
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
| | - Jianping Xie
- State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Chongqing, China
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9
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Araújo CL, Alves J, Nogueira W, Pereira LC, Gomide AC, Ramos R, Azevedo V, Silva A, Folador A. Prediction of new vaccine targets in the core genome of Corynebacterium pseudotuberculosis through omics approaches and reverse vaccinology. Gene 2019; 702:36-45. [PMID: 30928361 DOI: 10.1016/j.gene.2019.03.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/15/2019] [Accepted: 03/21/2019] [Indexed: 12/11/2022]
Abstract
Corynebacterium pseudotuberculosis is the etiologic agent of veterinary relevance diseases, such as caseous lymphadenitis, affecting different animal species causing damage to the global agribusiness. So far, there are no completely effective treatment methods to overcome the impacts caused by this pathogen. Several genomes of the species are deposited on public databases, allowing the execution of studies related to the pan-genomic approach. In this study, we used an integrated in silico workflow to prospect novel putative targets using the core genome, a set of shared genes among 65 C. pseudotuberculosis strains. Subsequently, through RNA-Seq data of the same abiotic stresses in two strains, we selected only induced genes to compose the reverse vaccinology workflow based in two different strategies. Our results predicted six probable antigens in both analysis, which indicates that they have a strong potential to be used in further studies as vaccine targets against this bacterium.
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Affiliation(s)
- Carlos Leonardo Araújo
- Laboratory of Genomics and Bioinformatics, Center of Genomics and System Biology, Federal University of Pará, Belém, Pará, Brazil
| | - Jorianne Alves
- Laboratory of Genomics and Bioinformatics, Center of Genomics and System Biology, Federal University of Pará, Belém, Pará, Brazil
| | - Wylerson Nogueira
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Lino César Pereira
- Laboratory of Genomics and Bioinformatics, Center of Genomics and System Biology, Federal University of Pará, Belém, Pará, Brazil
| | - Anne Cybelle Gomide
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Rommel Ramos
- Laboratory of Genomics and Bioinformatics, Center of Genomics and System Biology, Federal University of Pará, Belém, Pará, Brazil
| | - Vasco Azevedo
- Department of General Biology, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Artur Silva
- Laboratory of Genomics and Bioinformatics, Center of Genomics and System Biology, Federal University of Pará, Belém, Pará, Brazil
| | - Adriana Folador
- Laboratory of Genomics and Bioinformatics, Center of Genomics and System Biology, Federal University of Pará, Belém, Pará, Brazil.
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Pacl HT, Reddy VP, Saini V, Chinta KC, Steyn AJC. Host-pathogen redox dynamics modulate Mycobacterium tuberculosis pathogenesis. Pathog Dis 2018; 76:4972762. [PMID: 29873719 PMCID: PMC5989597 DOI: 10.1093/femspd/fty036] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/13/2018] [Indexed: 12/18/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, encounters variable and hostile environments within the host. A major component of these hostile conditions is reductive and oxidative stresses induced by factors modified by the host immune response, such as oxygen tension, NO or CO gases, reactive oxygen and nitrogen intermediates, the availability of different carbon sources and changes in pH. It is therefore essential for Mtb to continuously monitor and appropriately respond to the microenvironment. To this end, Mtb has developed various redox-sensitive systems capable of monitoring its intracellular redox environment and coordinating a response essential for virulence. Various aspects of Mtb physiology are regulated by these systems, including drug susceptibility, secretion systems, energy metabolism and dormancy. While great progress has been made in understanding the mechanisms and pathways that govern the response of Mtb to the host's redox environment, many questions in this area remain unanswered. The answers to these questions are promising avenues for addressing the tuberculosis crisis.
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Affiliation(s)
- Hayden T Pacl
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Vineel P Reddy
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Vikram Saini
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Krishna C Chinta
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
| | - Adrie J C Steyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
- Centers for AIDS Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama 35205, USA
- Africa Health Research Institute, K-RITH Tower Building, Durban 4001, South Africa
- School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, University of KwaZulu-Natal, Durban 4001, South Africa
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11
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Regulation of the CRISPR-Associated Genes by Rv2837c (CnpB) via an Orn-Like Activity in Tuberculosis Complex Mycobacteria. J Bacteriol 2018; 200:JB.00743-17. [PMID: 29378893 DOI: 10.1128/jb.00743-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 01/25/2018] [Indexed: 12/14/2022] Open
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-associated proteins (Cas) provide bacteria and archaea with adaptive immunity to specific DNA invaders. Mycobacterium tuberculosis encodes a type III CRISPR-Cas system that has not been experimentally explored. In this study, we found that the CRISPR-Cas systems of both M. tuberculosis and Mycobacterium bovis BCG were highly upregulated by deletion of Rv2837c (cnpB), which encodes a multifunctional protein that hydrolyzes cyclic di-AMP (c-di-AMP), cyclic di-GMP (c-di-GMP), and nanoRNAs (short oligonucleotides of 5 or fewer residues). By using genetic and biochemical approaches, we demonstrated that the CnpB-controlled transcriptional regulation of the CRISPR-Cas system is mediated by an Orn-like activity rather than by hydrolyzing the cyclic dinucleotides. Additionally, our results revealed that tuberculosis (TB) complex mycobacteria are functional in processing CRISPR RNAs (crRNAs), which are also more abundant in the ΔcnpB strain than in the parent strain. The elevated crRNA levels in the ΔcnpB strain could be partially reduced by expressing Escherichia coli orn Our findings provide new insight into transcriptional regulation of bacterial CRISPR-Cas systems.IMPORTANCE Clustered regularly interspaced short palindromic repeats (CRISPR) and the CRISPR-associated proteins (Cas) provide adaptive immunity to specific DNA invaders. M. tuberculosis encodes a type III CRISPR-Cas system that has not been experimentally explored. In this study, we first demonstrated that the CRISPR-Cas systems in tuberculosis (TB) complex mycobacteria are functional in processing CRISPR RNAs (crRNAs). We also showed that Rv2837c (CnpB) controls the expression of the CRISPR-Cas systems in TB complex mycobacteria through an oligoribonuclease (Orn)-like activity, which is very likely mediated by nanoRNA. Since little is known about regulation of CRISPR-Cas systems, our findings provide new insight into transcriptional regulation of bacterial CRISPR-Cas systems.
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12
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Rojas-Pirela M, Rigden DJ, Michels PA, Cáceres AJ, Concepción JL, Quiñones W. Structure and function of Per-ARNT-Sim domains and their possible role in the life-cycle biology of Trypanosoma cruzi. Mol Biochem Parasitol 2017; 219:52-66. [PMID: 29133150 DOI: 10.1016/j.molbiopara.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/12/2017] [Accepted: 11/02/2017] [Indexed: 02/07/2023]
Abstract
Per-ARNT-Sim (PAS) domains of proteins play important roles as modules for signalling and cellular regulation processes in widely diverse organisms such as Archaea, Bacteria, protists, plants, yeasts, insects and vertebrates. These domains are present in many proteins where they are used as sensors of stimuli and modules for protein interactions. Characteristically, they can bind a broad spectrum of molecules. Such binding causes the domain to trigger a specific cellular response or to make the protein containing the domain susceptible to responding to additional physical or chemical signals. Different PAS proteins have the ability to sense redox potential, light, oxygen, energy levels, carboxylic acids, fatty acids and several other stimuli. Such proteins have been found to be involved in cellular processes such as development, virulence, sporulation, adaptation to hypoxia, circadian cycle, metabolism and gene regulation and expression. Our analysis of the genome of different kinetoplastid species revealed the presence of PAS domains also in different predicted kinases from these protists. Open-reading frames coding for these PAS-kinases are unusually large. In addition, the products of these genes appear to contain in their structure combinations of domains uncommon in other eukaryotes. The physiological significance of PAS domains in these parasites, specifically in Trypanosoma cruzi, is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, Scotland, United Kingdom
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela.
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Guimarães WG, Gondim ACS, Costa PMDS, Gilles-Gonzalez MA, Lopes LGF, Carepo MSP, Sousa EHS. Insights into signal transduction by a hybrid FixL: Denaturation study of on and off states of a multi-domain oxygen sensor. J Inorg Biochem 2017; 172:129-137. [PMID: 28458146 DOI: 10.1016/j.jinorgbio.2017.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 03/21/2017] [Accepted: 04/02/2017] [Indexed: 11/17/2022]
Abstract
FixL from Rhizobium etli (ReFixL) is a hybrid oxygen sensor protein. Signal transduction in ReFixL is effected by a switch off of the kinase activity on binding of an oxygen molecule to ferrous heme iron in another domain. Cyanide can also inhibit the kinase activity upon binding to the heme iron in the ferric state. The unfolding by urea of the purified full-length ReFixL in both active pentacoordinate form, met-FixL(FeIII) and inactive cyanomet-FixL (FeIII-CN-) form was monitored by UV-visible absorption spectroscopy, circular dichroism (CD) and fluorescence spectroscopy. The CD and UV-visible absorption spectroscopy revealed two states during unfolding, whereas fluorescence spectroscopy identified a three-state unfolding mechanism. The unfolding mechanism was not altered for the active compared to the inactive state; however, differences in the ΔGH2O were observed. According to the CD results, compared to cyanomet-FixL, met-FixL was more stable towards chemical denaturation by urea (7.2 vs 4.8kJmol-1). By contrast, electronic spectroscopy monitoring of the Soret band showed cyanomet-FixL to be more stable than met-FixL (18.5 versus 36.2kJmol-1). For the three-state mechanism exhibited by fluorescence, the ΔGH2O for both denaturation steps were higher for the active-state met-FixL than for cyanomet-FixL. The overall stability of met-FixL is higher in comparison to cyanomet-FixL suggesting a more compact protein in the active form. Nonetheless, hydrogen bonding by bound cyanide in the inactive state promotes the stability of the heme domain. This work supports a model of signal transduction by FixL that is likely shared by other heme-based sensors.
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Affiliation(s)
- Wellinson G Guimarães
- Laboratório de Bioinorgânica, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, CEP 60455-760 Fortaleza, Ceará, Brazil
| | - Ana C S Gondim
- Laboratório de Bioinorgânica, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, CEP 60455-760 Fortaleza, Ceará, Brazil
| | - Pedro Mikael da Silva Costa
- Laboratório de Bioinorgânica, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, CEP 60455-760 Fortaleza, Ceará, Brazil
| | - Marie-Alda Gilles-Gonzalez
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9038, United States
| | - Luiz G F Lopes
- Laboratório de Bioinorgânica, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, CEP 60455-760 Fortaleza, Ceará, Brazil
| | - Marta S P Carepo
- Laboratório de Bioinorgânica, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, CEP 60455-760 Fortaleza, Ceará, Brazil.
| | - Eduardo H S Sousa
- Laboratório de Bioinorgânica, Departamento de Química Orgânica e Inorgânica, Universidade Federal do Ceará, CEP 60455-760 Fortaleza, Ceará, Brazil.
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Abstract
Haem-based sensors have emerged during the last 15 years as being a large family of proteins that occur in all kingdoms of life. These sensors are responsible mainly for detecting binding of O2, CO and NO and reporting the ligation status to an output domain with an enzymatic or macromolecule-binding property. A myriad of biological functions have been associated with these sensors, which are involved in vasodilation, bacterial symbiosis, chemotaxis and biofilm formation, among others. Here, we critically review several bacterial systems for O2 sensing that are extensively studied in many respects, focusing on the lessons that are important to advance the field.
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Chinta KC, Saini V, Glasgow JN, Mazorodze JH, Rahman MA, Reddy D, Lancaster JR, Steyn AJC. The emerging role of gasotransmitters in the pathogenesis of tuberculosis. Nitric Oxide 2016; 59:28-41. [PMID: 27387335 DOI: 10.1016/j.niox.2016.06.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 06/30/2016] [Indexed: 12/17/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is a facultative intracellular pathogen and the second largest contributor to global mortality caused by an infectious agent after HIV. In infected host cells, Mtb is faced with a harsh intracellular environment including hypoxia and the release of nitric oxide (NO) and carbon monoxide (CO) by immune cells. Hypoxia, NO and CO induce a state of in vitro dormancy where Mtb senses these gases via the DosS and DosT heme sensor kinase proteins, which in turn induce a set of ∼47 genes, known as the Mtb Dos dormancy regulon. On the contrary, both iNOS and HO-1, which produce NO and CO, respectively, have been shown to be important against mycobacterial disease progression. In this review, we discuss the impact of O2, NO and CO on Mtb physiology and in host responses to Mtb infection as well as the potential role of another major endogenous gas, hydrogen sulfide (H2S), in Mtb pathogenesis.
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Affiliation(s)
- Krishna C Chinta
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Vikram Saini
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; UAB Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joel N Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - James H Mazorodze
- KwaZulu-Natal Research Institute for TB and HIV (KRITH), Durban, South Africa
| | - Md Aejazur Rahman
- KwaZulu-Natal Research Institute for TB and HIV (KRITH), Durban, South Africa
| | - Darshan Reddy
- Department of Cardiothoracic Surgery, Nelson R Mandela School of Medicine, University of KwaZulu Natal, Durban, South Africa
| | - Jack R Lancaster
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adrie J C Steyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; KwaZulu-Natal Research Institute for TB and HIV (KRITH), Durban, South Africa; UAB Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
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Saini DK, Tyagi JS. High-Throughput Microplate Phosphorylation Assays Based on DevR-DevS/Rv2027c 2-Component Signal Transduction Pathway to Screen for Novel Antitubercular Compounds. ACTA ACUST UNITED AC 2016; 10:215-24. [PMID: 15809317 DOI: 10.1177/1087057104272090] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DevR-DevS (Rv3133c-Rv3132c) and DevR-Rv2027c have been established through their autophosphorylation and phospho-transfer properties to constitute bonafide regulatory 2-component systems of Mycobacterium tuberculosis. DevR has also been shown by others to play a key regulatory role in the expression of M. tuberculosis genes comprising the dormancy regulon. The authors describe high-throughput phosphorylation assays in a microplate format using DevS and Rv2027c histidine kinases and DevR response regulator proteins from M. tuberculosis. The assays were designed to measure [γ-32P]ATP-dependent autophosphorylation of DevS/Rv2027c and also the phosphotransfer reaction to DevR. First, the optimal reaction conditions were established using the conventional method of radiolabeling the 2-component proteins by [γ-32P]ATP and followed by gel electrophoresis-based analysis. Next, the assays were converted to a high-throughput format in which the radiolabeled protein retained on a filter using mixed cellulose ester-based 96-well filter plates was analyzed for radioactivity retention by scintillation counting. The utility of these assays to screen for inhibitors is illustrated using 2-mercaptobenzimidazole, ethidium bromide, and EDTA. The high quality and flexibility of these assays will enable their use in high-throughput screening for new antitubercular compounds directed against 2-component systems that comprise a novel target in dormant mycobacteria.
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Affiliation(s)
- Deepak Kumar Saini
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi 110-029, India
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Characterization of PAS domains in Frankia and selected Actinobacteria and their possible interaction with other co-domains for environmental adaptation. Symbiosis 2016. [DOI: 10.1007/s13199-016-0413-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mycobacterium tuberculosis Transcription Machinery: Ready To Respond to Host Attacks. J Bacteriol 2016; 198:1360-73. [PMID: 26883824 DOI: 10.1128/jb.00935-15] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Regulating responses to stress is critical for all bacteria, whether they are environmental, commensal, or pathogenic species. For pathogenic bacteria, successful colonization and survival in the host are dependent on adaptation to diverse conditions imposed by the host tissue architecture and the immune response. Once the bacterium senses a hostile environment, it must enact a change in physiology that contributes to the organism's survival strategy. Inappropriate responses have consequences; hence, the execution of the appropriate response is essential for survival of the bacterium in its niche. Stress responses are most often regulated at the level of gene expression and, more specifically, transcription. This minireview focuses on mechanisms of regulating transcription initiation that are required by Mycobacterium tuberculosis to respond to the arsenal of defenses imposed by the host during infection. In particular, we highlight how certain features of M. tuberculosis physiology allow this pathogen to respond swiftly and effectively to host defenses. By enacting highly integrated and coordinated gene expression changes in response to stress,M. tuberculosis is prepared for battle against the host defense and able to persist within the human population.
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Abstract
Two-component regulatory systems (2CRSs) are widely used by bacteria to sense and respond to environmental stimuli with coordinated changes in gene expression. Systems are normally comprised of a sensory kinase protein that activates a transcriptional regulator by phosphorylation. Mycobacteria have few 2CRSs, but they are of key importance for bacterial survival and play important roles in pathogenicity. Mycobacterium tuberculosis has 12 paired two-component regulatory systems (which include a system with two regulators and one sensor, and a split sensor system), as well as four orphan regulators. Several systems are involved in virulence, and disruption of different systems leads to attenuation or hypervirulence. PhoPR plays a major role in regulating cell wall composition, and its inactivation results in sufficient attenuation of M. tuberculosis that deletion strains are live vaccine candidates. MprAB controls the stress response and is required for persistent infections. SenX3-RegX3 is required for control of aerobic respiration and phosphate uptake, and PrrAB is required for adaptation to intracellular infection. MtrAB is an essential system that controls DNA replication and cell division. The remaining systems (KdpDE, NarL, TrcRS, TcrXY, TcrA, PdtaRS, and four orphan regulators) are less well understood. The structure and binding motifs for several regulators have been characterized, revealing variations in function and operation. The sensors are less well characterized, and stimuli for many remain to be confirmed. This chapter reviews our current understanding of the role of two-component systems in mycobacteria, in particular M. tuberculosis.
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Calder B, Soares NC, de Kock E, Blackburn JM. Mycobacterial proteomics: analysis of expressed proteomes and post-translational modifications to identify candidate virulence factors. Expert Rev Proteomics 2015; 12:21-35. [PMID: 25603863 DOI: 10.1586/14789450.2015.1007046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Mycobacterium tuberculosis bacillus has a number of unique features that make it a particularly effective human pathogen. Although genomic analysis has added to our current understanding of the molecular basis by which M. tuberculosis damages its host, proteomics may be better suited to describe the dynamic interactions between mycobacterial and host systems that underpin this disease. The M. tuberculosis proteome has been investigated using proteomics for over a decade, with increasingly sophisticated mass spectrometry technology and sensitive methods for comparative proteomic profiling. Deeper coverage of the M. tuberculosis proteome has led to the identification of hundreds of putative virulence determinants, as well as an unsurpassed coverage of post-translational modifications. Proteomics is therefore uniquely poised to contribute to our understanding of this pathogen, which may ultimately lead to better management of the disease.
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Affiliation(s)
- Bridget Calder
- Division of Medical Biochemistry, Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine (IDM), University of Cape Town, Anzio Rd, Observatory, Cape Town 7925, South Africa
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Tavares AH, Fernandes L, Bocca AL, Silva-Pereira I, Felipe MS. Transcriptomic reprogramming of genus Paracoccidioides in dimorphism and host niches. Fungal Genet Biol 2015; 81:98-109. [DOI: 10.1016/j.fgb.2014.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 01/27/2014] [Accepted: 01/31/2014] [Indexed: 01/04/2023]
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Singh N, Kumar A. Virulence factor SenX3 is the oxygen-controlled replication switch of Mycobacterium tuberculosis. Antioxid Redox Signal 2015; 22:603-13. [PMID: 25333974 PMCID: PMC4333250 DOI: 10.1089/ars.2014.6020] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
AIM Morphogenetic switching between the replicating and nonreplicating states of Mycobacterium tuberculosis is regulated by oxygen, nitric oxide, and carbon monoxide levels. The mechanisms by which M. tuberculosis senses these diatomic gases remain poorly understood. In this study, we have examined whether virulence factor SenX3 plays any role in oxygen sensing. RESULTS In this study, we demonstrate that the virulence factor SenX3 is a heme protein that acts as a three-way sensor with three levels of activity. The oxidation of SenX3 heme by oxygen leads to the activation of its kinase activity, whereas the deoxy-ferrous state confers a moderate kinase activity. The binding of nitric oxide and carbon monoxide inhibits kinase activity. Consistent with these biochemical properties, the SenX3 mutant of M. tuberculosis is capable of attaining a nonreplicating persistent state in response to hypoxic stress, but its regrowth on the restoration of ambient oxygen levels is significantly attenuated compared with the wild-type and the complemented mutant strains. Furthermore, the presence of signaling concentrations of nitric oxide and carbon monoxide was able to inhibit the regrowth of M. tuberculosis in response to ambient oxygen levels. INNOVATION AND CONCLUSIONS Evidence presented in this study delineates a plausible mechanism explaining the oxygen-induced reactivation of tuberculosis diseases in humans after many years of latent infection. Furthermore, this study implicates nitric oxide and carbon monoxide in the inhibition of mycobacterial growth from the nonreplicating state.
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Affiliation(s)
- Nisha Singh
- Department of Infectious Diseases and Immunity, Council of Scientific and Industrial Research, Institute of Microbial Technology , Chandigarh, India
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Reprogramming of Yersinia from virulent to persistent mode revealed by complex in vivo RNA-seq analysis. PLoS Pathog 2015; 11:e1004600. [PMID: 25590628 PMCID: PMC4295882 DOI: 10.1371/journal.ppat.1004600] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 12/03/2014] [Indexed: 11/19/2022] Open
Abstract
We recently found that Yersinia pseudotuberculosis can be used as a model of persistent bacterial infections. We performed in vivo RNA-seq of bacteria in small cecal tissue biopsies at early and persistent stages of infection to determine strategies associated with persistence. Comprehensive analysis of mixed RNA populations from infected tissues revealed that Y. pseudotuberculosis undergoes transcriptional reprogramming with drastic down-regulation of T3SS virulence genes during persistence when the pathogen resides within the cecum. At the persistent stage, the expression pattern in many respects resembles the pattern seen in vitro at 26oC, with for example, up-regulation of flagellar genes and invA. These findings are expected to have impact on future rationales to identify suitable bacterial targets for new antibiotics. Other genes that are up-regulated during persistence are genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress, which indicates the influence of different environmental cues. We found that the Crp/CsrA/RovA regulatory cascades influence the pattern of bacterial gene expression during persistence. Furthermore, arcA, fnr, frdA, and wrbA play critical roles in persistence. Our findings suggest a model for the life cycle of this enteropathogen with reprogramming from a virulent to an adapted phenotype capable of persisting and spreading by fecal shedding. To establish infection and colonize within a host, infecting pathogens have to cope with a variety of destructive surroundings. The food-borne pathogen Y. pseudotuberculosis can cause persistent infection in mice. Upon infection, Y. pseudotuberculosis passes the anti-microbial gastrointestinal milieu and finally remains associated with lymphoid follicles in cecal tissue surrounded by polymorphonuclear leukocytes, indicating that the bacteria are exposed to multiple environmental cues. We performed complex RNA-seq of small cecal biopsies of infected mice to reveal Y. pseudotuberculosis gene expression in vivo. We found that Y. pseudotuberculosis underwent reprogramming from a virulent phenotype, expressing virulence genes during early infection, to an adapted phenotype capable of persisting in the harsh cecal environment. Persistence was characterized by a novel expression pattern with down-regulation of virulence genes and up-regulation of genes involved in anaerobiosis, chemotaxis, and protection against oxidative and acidic stress. Mutagenesis of selected genes revealed that the regulator rovA was critical for the establishment of infection, and that arcA, fnr, frdA, and wrbA play critical roles in maintaining infection for long periods of time. Our study shows the power of RNA deep sequencing, which can be used to reveal the in vivo expression patterns of small amounts of bacteria in complex intestinal environments.
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Rifat D, Belchis DA, Karakousis PC. senX3-independent contribution of regX3 to Mycobacterium tuberculosis virulence. BMC Microbiol 2014; 14:265. [PMID: 25344463 PMCID: PMC4213456 DOI: 10.1186/s12866-014-0265-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/09/2014] [Indexed: 01/27/2023] Open
Abstract
Background Mycobacterium tuberculosis (Mtb) must adapt to various stress conditions during host infection. The two-component regulatory system (2CRS) SenX3-RegX3 is required for Mtb virulence. We showed recently that the senX3-regX3 intergenic region contains promoter activity, driving senX3-independent regX3 expression. In the current study, we tested the hypothesis that RegX3 has a SenX3-independent role in Mtb virulence. The gene expression patterns, growth, and survival of mutants containing transposon insertions in senX3 (senX3::Tn) and regX3 (regX3::Tn) were compared to those of their respective complemented strains and the isogenic wild-type parent strain during axenic growth in nutrient-rich broth, phosphate depletion, nutrient starvation, and in the lungs of BALB/c mice. Results regX3 expression was reduced in senX3::Tn during phosphate depletion and nutrient starvation, and expression of the phosphate-specific transport gene pstC2 was reduced similarly in senX3::Tn and regX3::Tn during phosphate depletion. Although senX3 and regX3 were each dispensable for Mtb growth in nutrient-rich broth, disruption of senX3 or regX3 caused a similar growth defect during phosphate depletion. Interestingly, senX3::Tn, in which monocistronic regX3 expression is preserved, showed significantly higher survival relative to regX3::Tn after 7 days of nutrient starvation (p <0.01), and in mouse lungs at Day 31 (p < 0.01), Day 62 (p < 0.01), and Day 124 (p = 0.05) after aerosol infection. Conclusion Our data demonstrate the specificity of the senX3-regX3 2CRS for sensing and responding to low ambient phosphate, but also raise the possibility that RegX3 may function independently of its cognate sensor histidine kinase.
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Rifat D, Karakousis PC. Differential regulation of the two-component regulatory system senX3-regX3 in Mycobacterium tuberculosis. MICROBIOLOGY-SGM 2014; 160:1125-1133. [PMID: 24722908 DOI: 10.1099/mic.0.077180-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The highly successful pathogen Mycobacterium tuberculosis (Mtb) has evolved strategies to adapt to various stress conditions, thus promoting survival within the infected host. The two-component regulatory system (2CRS) senX3-regX3, which has been implicated in the Mtb response to inorganic phosphate depletion, is believed to behave as an auto-regulatory bicistronic operon. Unlike other 2CRS, Mtb senX3-regX3 features an intergenic region (IR) containing several mycobacterium interspersed repetitive units (MIRU) of unknown function. In this study, we used a lacZ reporter system to study the promoter activity of the 5' untranslated region of senX3, and that of various numbers of MIRUs in the senX3-regX3 IR, during axenic Mtb growth in nutrient-rich broth, and upon exposure to growth-restricting conditions. Activity of the senX3 promoter was induced during phosphate depletion and nutrient starvation, and IR promoter activity under these conditions was directly proportional to the number of MIRUs present. Quantitative reverse transcriptase (qRT)-PCR analysis of exponentially growing Mtb revealed monocistronic transcription of senX3 and regX3, and, to a lesser degree, bicistronic transcription of the operon. In addition, we observed primarily monocistronic upregulation of regX3 during phosphate depletion of Mtb, which was confirmed by Northern analysis in wild-type Mtb and by RT-PCR in a senX3-disrupted mutant, while upregulation of regX3 in nutrient-starved Mtb was chiefly bicistronic. Our findings of differential regulation of senX3-regX3 highlight the potential regulatory role of MIRUs in the Mtb genome and provide insight into the regulatory mechanisms underlying Mtb adaptation to physiologically relevant conditions.
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Affiliation(s)
- Dalin Rifat
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Petros C Karakousis
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Sanyal S, Banerjee SK, Banerjee R, Mukhopadhyay J, Kundu M. Polyphosphate kinase 1, a central node in the stress response network of Mycobacterium tuberculosis, connects the two-component systems MprAB and SenX3-RegX3 and the extracytoplasmic function sigma factor, sigma E. MICROBIOLOGY-SGM 2013; 159:2074-2086. [PMID: 23946493 DOI: 10.1099/mic.0.068452-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Polyphosphate (poly P) metabolism regulates the stress response in mycobacteria. Here we describe the regulatory architecture of a signal transduction system involving the two-component system (TCS) SenX3-RegX3, the extracytoplasmic function sigma factor sigma E (SigE) and the poly P-synthesizing enzyme polyphosphate kinase 1 (PPK1). The ppk1 promoter of Mycobacterium tuberculosis is activated under phosphate starvation. This is attenuated upon deletion of an imperfect palindrome likely representing a binding site for the response regulator RegX3, a component of the two-component system SenX3-RegX3 that responds to phosphate starvation. Binding of phosphorylated RegX3 to this site was confirmed by electrophoretic mobility shift assay. The activity of the ppk1 promoter was abrogated upon deletion of a putative SigE binding site. Pull-down of SigE from M. tuberculosis lysates of phosphate-starved cells with a biotinylated DNA harbouring the SigE binding site confirmed the likely binding of SigE to the ppk1 promoter. In vitro transcription corroborated the involvement of SigE in ppk1 transcription. Finally, the overexpression of RseA (anti-SigE) attenuated ppk1 expression under phosphate starvation, supporting the role of SigE in ppk1 transcription. The regulatory elements identified in ppk1 transcription in this study, combined with our earlier observation that PPK1 is itself capable of regulating sigE expression via the MprAB TCS, suggest the presence of multiple positive-feedback loops in this signalling circuit. In combination with the sequestering effect of RseA, we hypothesize that this architecture could be linked to bistability in the system that, in turn, could be a key element of persistence in M. tuberculosis.
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Affiliation(s)
- Sourav Sanyal
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Srijon Kaushik Banerjee
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Rajdeep Banerjee
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Jayanta Mukhopadhyay
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
| | - Manikuntala Kundu
- Department of Chemistry, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India
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Involvement of EnvZ–OmpR two-component system in virulence control of Escherichia coli in Drosophila melanogaster. Biochem Biophys Res Commun 2013; 438:306-11. [DOI: 10.1016/j.bbrc.2013.07.062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 07/16/2013] [Indexed: 11/20/2022]
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Shah N, Gaupp R, Moriyama H, Eskridge KM, Moriyama EN, Somerville GA. Reductive evolution and the loss of PDC/PAS domains from the genus Staphylococcus. BMC Genomics 2013; 14:524. [PMID: 23902280 PMCID: PMC3734008 DOI: 10.1186/1471-2164-14-524] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 07/25/2013] [Indexed: 02/02/2023] Open
Abstract
Background The Per-Arnt-Sim (PAS) domain represents a ubiquitous structural fold that is involved in bacterial sensing and adaptation systems, including several virulence related functions. Although PAS domains and the subclass of PhoQ-DcuS-CitA (PDC) domains have a common structure, there is limited amino acid sequence similarity. To gain greater insight into the evolution of PDC/PAS domains present in the bacterial kingdom and staphylococci in specific, the PDC/PAS domains from the genomic sequences of 48 bacteria, representing 5 phyla, were identified using the sensitive search method based on HMM-to-HMM comparisons (HHblits). Results A total of 1,007 PAS domains and 686 PDC domains distributed over 1,174 proteins were identified. For 28 Gram-positive bacteria, the distribution, organization, and molecular evolution of PDC/PAS domains were analyzed in greater detail, with a special emphasis on the genus Staphylococcus. Compared to other bacteria the staphylococci have relatively fewer proteins (6–9) containing PDC/PAS domains. As a general rule, the staphylococcal genomes examined in this study contain a core group of seven PDC/PAS domain-containing proteins consisting of WalK, SrrB, PhoR, ArlS, HssS, NreB, and GdpP. The exceptions to this rule are: 1) S. saprophyticus lacks the core NreB protein; 2) S. carnosus has two additional PAS domain containing proteins; 3) S. epidermidis, S. aureus, and S. pseudintermedius have an additional protein with two PDC domains that is predicted to code for a sensor histidine kinase; 4) S. lugdunensis has an additional PDC containing protein predicted to be a sensor histidine kinase. Conclusions This comprehensive analysis demonstrates that variation in PDC/PAS domains among bacteria has limited correlations to the genome size or pathogenicity; however, our analysis established that bacteria having a motile phase in their life cycle have significantly more PDC/PAS-containing proteins. In addition, our analysis revealed a tremendous amount of variation in the number of PDC/PAS-containing proteins within genera. This variation extended to the Staphylococcus genus, which had between 6 and 9 PDC/PAS proteins and some of these appear to be previously undescribed signaling proteins. This latter point is important because most staphylococcal proteins that contain PDC/PAS domains regulate virulence factor synthesis or antibiotic resistance.
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Affiliation(s)
- Neethu Shah
- Department of Computer Science and Engineering, University of Nebraska, Lincoln, NE 68588-0115, USA
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Lv H, Hu L, Hu Q, Wei Q, Shen P. Expression and purification of SenX3 from the Mycobacterium tuberculosis strain H37Rv in Escherichia coli. Mol Med Rep 2013; 7:1960-4. [PMID: 23624571 DOI: 10.3892/mmr.2013.1449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 04/11/2013] [Indexed: 11/06/2022] Open
Abstract
Infection with the bacterium Mycobacterium tuberculosis (MTB) causes tuberculosis, a pulmonary infection that may be fatal if left untreated. Misuse or mismanagement of tuberculosis drugs may lead to drug-resistant pathogen forms that are difficult to treat and contribute to a global health problem. The MTB SenX3/RegX3 signal transduction system allows bacteria to externally sense the environment and mediate an appropriate internal response; SenX3 is also associated with MTB virulence, suggesting that this protein may provide a potential therapeutic target. To investigate the role of SenX3 and MTB drug resistance, SenX3 was cloned, expressed and purified in Escherichia coli. SenX3 was cloned from the genome of the MTB strain H37Rv by polymerase chain reaction and an internal NcoI restriction site was destroyed by site-directed mutagenesis to allow cloning into the pET-28b prokaryotic expression vector. SenX3 expression from the resulting pET‑28b-mSenX3 plasmid was induced with isopropyl β-D-thiogalactoside and the protein was purified using Ni-NTA agarose affinity chromatography. A pure protein of the expected size was identified. The examination of purified SenX3 protein is considered to enable the in‑depth investigation of SenX3-mediated drug resistance.
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Affiliation(s)
- Huoyang Lv
- Center of Laboratory Medicine, Zhejiang Provincial People's Hospital, Hangzhou, Zhejiang 310014, P.R. China.
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Forrellad MA, Klepp LI, Gioffré A, Sabio y García J, Morbidoni HR, de la Paz Santangelo M, Cataldi AA, Bigi F. Virulence factors of the Mycobacterium tuberculosis complex. Virulence 2012; 4:3-66. [PMID: 23076359 PMCID: PMC3544749 DOI: 10.4161/viru.22329] [Citation(s) in RCA: 379] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Mycobacterium tuberculosis complex (MTBC) consists of closely related species that cause tuberculosis in both humans and animals. This illness, still today, remains to be one of the leading causes of morbidity and mortality throughout the world. The mycobacteria enter the host by air, and, once in the lungs, are phagocytated by macrophages. This may lead to the rapid elimination of the bacillus or to the triggering of an active tuberculosis infection. A large number of different virulence factors have evolved in MTBC members as a response to the host immune reaction. The aim of this review is to describe the bacterial genes/proteins that are essential for the virulence of MTBC species, and that have been demonstrated in an in vivo model of infection. Knowledge of MTBC virulence factors is essential for the development of new vaccines and drugs to help manage the disease toward an increasingly more tuberculosis-free world.
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James JN, Hasan ZU, Ioerger TR, Brown AC, Personne Y, Carroll P, Ikeh M, Tilston-Lunel NL, Palavecino C, Sacchettini JC, Parish T. Deletion of SenX3-RegX3, a key two-component regulatory system of Mycobacterium smegmatis, results in growth defects under phosphate-limiting conditions. MICROBIOLOGY-SGM 2012; 158:2724-2731. [PMID: 22956756 DOI: 10.1099/mic.0.060319-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two component regulatory systems are key elements in the control of bacterial gene expression in response to environmental perturbations. The SenX3-RegX3 system is implicated in the control of phosphate uptake in Mycobacterium smegmatis and Mycobacterium tuberculosis. regX3 is reported to be essential in M. smegmatis, but not in M. tuberculosis. We attempted to construct complete senX3-regX3 operon deletion strains of M. smegmatis; initially we found that the operon could only be deleted when another functional copy was provided. Using a strain in which the only functional copy of the operon was present on an integrating plasmid, we attempted to replace the functional copy with an empty vector. Surprisingly, we obtained strains in which the functional copy had been deleted from the chromosome at a low frequency. We deleted the senX3 gene in a similar fashion, but it was not possible to delete regX3 alone. To identify possible compensatory mutations we sequenced the whole genome of two deletion strains and the wild-type. A synonymous single nucleotide polymorphism (SNP) in a lipoprotein was found in all deletion strains, but not the parental strains, and a frameshift mutation in nhaA was identified in three of the four deletion strains. Operon deletion strains were more sensitive to phosphate limitation, showing a reduced ability to grow at lower phosphate concentrations. The M. tuberculosis operon was able to functionally complement the growth phenotype in M. smegmatis under phosphate-replete conditions, but not under low phosphate conditions, reinforcing the difference between the two species. Our data show that, in contrast with previous reports, it is possible to delete the operon in M. smegmatis, possibly due to the accumulation of compensatory mutations, and that the deletion does affect growth in phosphate.
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Affiliation(s)
- Jade N James
- Queen Mary University of London, Barts and the London, London, UK
| | | | - Thomas R Ioerger
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX, USA
| | - Amanda C Brown
- Queen Mary University of London, Barts and the London, London, UK
| | - Yoann Personne
- Queen Mary University of London, Barts and the London, London, UK
| | - Paul Carroll
- Queen Mary University of London, Barts and the London, London, UK
| | - Melanie Ikeh
- Queen Mary University of London, Barts and the London, London, UK
| | | | | | - James C Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Tanya Parish
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, USA.,Queen Mary University of London, Barts and the London, London, UK
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Lamrabet O, Drancourt M. Genetic engineering of Mycobacterium tuberculosis: a review. Tuberculosis (Edinb) 2012; 92:365-76. [PMID: 22789498 DOI: 10.1016/j.tube.2012.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 06/06/2012] [Indexed: 01/01/2023]
Abstract
Genetic engineering has been used for decades to mutate and delete genes in the Mycobacterium tuberculosis genome with the translational goal of producing attenuated mutants with conserved susceptibility to antituberculous antibiotics. The development of plasmids and mycobacteriophages that can transfer DNA into the M. tuberculosis chromosome has effectively overcome M. tuberculosis slow growth rate and the capsule and mycolic acid wall, which limit DNA uptake. The use of genetic engineering techniques has shed light on many aspects of pathogenesis mechanisms, including cellular growth, mycolic acid biosynthesis, metabolism, drug resistance and virulence. Moreover, such research gave clues to the development of new vaccines or new drugs for routine clinical practice. The use of genetic engineering tools is mainly based on the underlying concept that altering or reducing the M. tuberculosis genome could decrease its virulence. A contrario, recent post-genomic analyses indicated that reduced bacterial genomes are often associated with increased bacterial virulence and that M. tuberculosis acquired genes by lateral genetic exchange during its evolution. Therefore, ancestors utilizing genetic engineering to add genes to the M. tuberculosis genome may lead to new vaccines and the availability of M. tuberculosis isolates with increased susceptibility to antituberculous antibiotics.
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Affiliation(s)
- Otmane Lamrabet
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, UMR CNRS 6236 IRD 3R198, Méditerranée Infection, FRIDMM, Aix-Marseille Université, Marseille, France.
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De Majumdar S, Vashist A, Dhingra S, Gupta R, Singh A, Challu VK, Ramanathan VD, Kumar P, Tyagi JS. Appropriate DevR (DosR)-mediated signaling determines transcriptional response, hypoxic viability and virulence of Mycobacterium tuberculosis. PLoS One 2012; 7:e35847. [PMID: 22563409 PMCID: PMC3338549 DOI: 10.1371/journal.pone.0035847] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Accepted: 03/23/2012] [Indexed: 11/25/2022] Open
Abstract
Background The DevR(DosR) regulon is implicated in hypoxic adaptation and virulence of Mycobacterium tuberculosis. The present study was designed to decipher the impact of perturbation in DevR-mediated signaling on these properties. Methodology/Principal Findings M. tb complemented (Comp) strains expressing different levels of DevR were constructed in Mut1* background (expressing DevR N-terminal domain in fusion with AphI (DevRN-Kan) and in Mut2ΔdevR background (deletion mutant). They were compared for their hypoxia adaptation and virulence properties. Diverse phenotypes were noted; basal level expression (∼5.3±2.3 µM) when induced to levels equivalent to WT levels (∼25.8±9.3 µM) was associated with robust DevR regulon induction and hypoxic adaptation (Comp 9* and 10*), whereas low-level expression (detectable at transcript level) as in Comp 11* and Comp15 was associated with an adaptation defect. Intermediate-level expression (∼3.3±1.2 µM) partially restored hypoxic adaptation functions in Comp2, but not in Comp1* bacteria that co-expressed DevRN-Kan. Comp* strains in Mut1* background also exhibited diverse virulence phenotypes; high/very low-level DevR expression was associated with virulence whereas intermediate-level expression was associated with low virulence. Transcription profiling and gene expression analysis revealed up-regulation of the phosphate starvation response (PSR) in Mut1* and Comp11* bacteria, but not in WT/Mut2ΔdevR/other Comp strains, indicating a plasticity in expression pathways that is determined by the magnitude of signaling perturbation through DevRN-Kan. Conclusions/Significance A minimum DevR concentration of ∼3.3±1.2 µM (as in Comp2 bacteria) is required to support HspX expression in the standing culture hypoxia model. The relative intracellular concentrations of DevR and DevRN-Kan appear to be critical for determining dormancy regulon induction, hypoxic adaptation and virulence. Dysregulated DevRN-Kan-mediated signaling selectively triggers the PSR in bacteria expressing no/very low level of DevR. Our findings illustrate the important role of appropriate two-component- mediated signaling in pathogen physiology and the resilience of bacteria when such signaling is perturbed.
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Affiliation(s)
| | - Atul Vashist
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Sakshi Dhingra
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Rajesh Gupta
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Alka Singh
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | | | - V. D. Ramanathan
- Department of Pathology, Tuberculosis Research Centre, Chennai, India
| | | | - Jaya Sivaswami Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
- * E-mail:
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Song L, Sudhakar P, Wang W, Conrads G, Brock A, Sun J, Wagner-Döbler I, Zeng AP. A genome-wide study of two-component signal transduction systems in eight newly sequenced mutans streptococci strains. BMC Genomics 2012; 13:128. [PMID: 22475007 PMCID: PMC3353171 DOI: 10.1186/1471-2164-13-128] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 04/04/2012] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Mutans streptococci are a group of gram-positive bacteria including the primary cariogenic dental pathogen Streptococcus mutans and closely related species. Two component systems (TCSs) composed of a signal sensing histidine kinase (HK) and a response regulator (RR) play key roles in pathogenicity, but have not been comparatively studied for these oral bacterial pathogens. RESULTS HKs and RRs of 8 newly sequenced mutans streptococci strains, including S. sobrinus DSM20742, S. ratti DSM20564 and six S. mutans strains, were identified and compared to the TCSs of S. mutans UA159 and NN2025, two previously genome sequenced S. mutans strains. Ortholog analysis revealed 18 TCS clusters (HK-RR pairs), 2 orphan HKs and 2 orphan RRs, of which 8 TCS clusters were common to all 10 strains, 6 were absent in one or more strains, and the other 4 were exclusive to individual strains. Further classification of the predicted HKs and RRs revealed interesting aspects of their putative functions. While TCS complements were comparable within the six S. mutans strains, S. sobrinus DSM20742 lacked TCSs possibly involved in acid tolerance and fructan catabolism, and S. ratti DSM20564 possessed 3 unique TCSs but lacked the quorum-sensing related TCS (ComDE). Selected computational predictions were verified by PCR experiments. CONCLUSIONS Differences in the TCS repertoires of mutans streptococci strains, especially those of S. sobrinus and S. ratti in comparison to S. mutans, imply differences in their response mechanisms for survival in the dynamic oral environment. This genomic level study of TCSs should help in understanding the pathogenicity of these mutans streptococci strains.
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Affiliation(s)
- Lifu Song
- Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology, Hamburg, Germany
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35
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Bretl DJ, Demetriadou C, Zahrt TC. Adaptation to environmental stimuli within the host: two-component signal transduction systems of Mycobacterium tuberculosis. Microbiol Mol Biol Rev 2011; 75:566-82. [PMID: 22126994 PMCID: PMC3232741 DOI: 10.1128/mmbr.05004-11] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pathogenic microorganisms encounter a variety of environmental stresses following infection of their respective hosts. Mycobacterium tuberculosis, the etiological agent of tuberculosis, is an unusual bacterial pathogen in that it is able to establish lifelong infections in individuals within granulomatous lesions that are formed following a productive immune response. Adaptation to this highly dynamic environment is thought to be mediated primarily through transcriptional reprogramming initiated in response to recognition of stimuli, including low-oxygen tension, nutrient depletion, reactive oxygen and nitrogen species, altered pH, toxic lipid moieties, cell wall/cell membrane-perturbing agents, and other environmental cues. To survive continued exposure to these potentially adverse factors, M. tuberculosis encodes a variety of regulatory factors, including 11 complete two-component signal transduction systems (TCSSs) and several orphaned response regulators (RRs) and sensor kinases (SKs). This report reviews our current knowledge of the TCSSs present in M. tuberculosis. In particular, we discuss the biochemical and functional characteristics of individual RRs and SKs, the environmental stimuli regulating their activation, the regulons controlled by the various TCSSs, and the known or postulated role(s) of individual TCSSs in the context of M. tuberculosis physiology and/or pathogenesis.
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Affiliation(s)
| | | | - Thomas C. Zahrt
- Center for Infectious Disease Research and Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, Wisconsin 53226-0509
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Pang X, Cao G, Neuenschwander PF, Haydel SE, Hou G, Howard ST. The β-propeller gene Rv1057 of Mycobacterium tuberculosis has a complex promoter directly regulated by both the MprAB and TrcRS two-component systems. Tuberculosis (Edinb) 2011; 91 Suppl 1:S142-9. [PMID: 22099420 DOI: 10.1016/j.tube.2011.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The β-propeller gene Rv1057 of Mycobacterium tuberculosis is activated by envelope stress and was first characterized as a regulatory target of the TrcRS two-component system (TCS). Rv1057 expression is repressed by TrcRS, and the Rv1057 proximal promoter contains a TrcR binding site. In this study, we determined that Rv1057 is also directly regulated by MprAB, a TCS associated with envelope stress. Multiple potential MprA binding sites (MprA boxes) were identified in the 1 kb intergenic region upstream of Rv1057, and four sites were shown to bind MprA. Although MprA boxes were found in the proximal promoter, analyses suggest that MprA and TrcR do not compete for binding in this region. An MprAB-dependent, detergent-inducible transcriptional start point for Rv1057 was identified downstream of the MprA boxes, and a second TrcR binding site and small ORF of the 13E12 family were discovered in the distal promoter. MprAB was required for activation of Rv1057 during growth in macrophages and under detergent stress, and lacZ promoter constructs suggest the entire intergenic region is utilized during MprAB-dependent activation of Rv1057. These findings indicate that Rv1057 has an extensive and complex promoter, and provide evidence for coordinated regulation of stress response genes by TCSs.
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Affiliation(s)
- Xiuhua Pang
- The State Key Lab of Microbial Technology, Shandong University, Jinan 250100, China.
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Roberts G, Vadrevu IS, Madiraju MV, Parish T. Control of CydB and GltA1 expression by the SenX3 RegX3 two component regulatory system of Mycobacterium tuberculosis. PLoS One 2011; 6:e21090. [PMID: 21698211 PMCID: PMC3116866 DOI: 10.1371/journal.pone.0021090] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 05/20/2011] [Indexed: 01/05/2023] Open
Abstract
Two component regulatory systems are used widely by bacteria to coordinate changes in global gene expression profiles in response to environmental signals. The SenX3-RegX3 two component system of Mycobacterium tuberculosis has previously been shown to play a role in virulence and phosphate-responsive control of gene expression. We demonstrate that expression of SenX3-RegX3 is controlled in response to growth conditions, although the absolute changes are small. Global gene expression profiling of a RegX3 deletion strain and wild-type strain in different culture conditions (static, microaerobic, anaerobic), as well as in an over-expressing strain identified a number of genes with changed expression patterns. Among those were genes previously identified as differentially regulated in aerobic culture, including ald (encoding alanine dehydrogenase) cyd,encoding a subunit of the cytochrome D ubiquinol oxidase, and gltA1, encoding a citrate synthase. Promoter activity in the upstream regions of both cydB and gltA1 was altered in the RegX3 deletion strain. DNA-binding assays confirmed that RegX3 binds to the promoter regions of ald, cydB and gltA1 in a phosphorylation-dependent manner. Taken together these data suggest a direct role for the SenX-RegX3 system in modulating expression of aerobic respiration, in addition to its role during phosphate limitation.
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Affiliation(s)
- Gretta Roberts
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom
| | - Indumathi S. Vadrevu
- Biomedical Research, The University of Texas Health Center, Tyler, Texas, United States of America
| | - Murty V. Madiraju
- Biomedical Research, The University of Texas Health Center, Tyler, Texas, United States of America
| | - Tanya Parish
- Queen Mary University of London, Barts and the London School of Medicine and Dentistry, London, United Kingdom
- Infectious Disease Research Institute, Seattle, Washington, United States of America
- * E-mail:
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Rossi F, Khanduja JS, Bortoluzzi A, Houghton J, Sander P, Güthlein C, Davis EO, Springer B, Böttger EC, Relini A, Penco A, Muniyappa K, Rizzi M. The biological and structural characterization of Mycobacterium tuberculosis UvrA provides novel insights into its mechanism of action. Nucleic Acids Res 2011; 39:7316-28. [PMID: 21622956 PMCID: PMC3167621 DOI: 10.1093/nar/gkr271] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Mycobacterium tuberculosis is an extremely well adapted intracellular human pathogen that is exposed to multiple DNA damaging chemical assaults originating from the host defence mechanisms. As a consequence, this bacterium is thought to possess highly efficient DNA repair machineries, the nucleotide excision repair (NER) system amongst these. Although NER is of central importance to DNA repair in M. tuberculosis, our understanding of the processes in this species is limited. The conserved UvrABC endonuclease represents the multi-enzymatic core in bacterial NER, where the UvrA ATPase provides the DNA lesion-sensing function. The herein reported genetic analysis demonstrates that M. tuberculosis UvrA is important for the repair of nitrosative and oxidative DNA damage. Moreover, our biochemical and structural characterization of recombinant M. tuberculosis UvrA contributes new insights into its mechanism of action. In particular, the structural investigation reveals an unprecedented conformation of the UvrB-binding domain that we propose to be of functional relevance. Taken together, our data suggest UvrA as a potential target for the development of novel anti-tubercular agents and provide a biochemical framework for the identification of small-molecule inhibitors interfering with the NER activity in M. tuberculosis.
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Affiliation(s)
- Franca Rossi
- DiSCAFF, University of Piemonte Orientale Amedeo Avogadro, Via Bovio 6, 28100 Novara, Italy
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Muttucumaru DN, Smith DA, McMinn EJ, Reese V, Coler RN, Parish T. Mycobacterium tuberculosis Rv0198c, a putative matrix metalloprotease is involved in pathogenicity. Tuberculosis (Edinb) 2011; 91:111-6. [DOI: 10.1016/j.tube.2010.11.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 10/11/2010] [Accepted: 11/27/2010] [Indexed: 11/25/2022]
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Stallings CL, Glickman MS. Is Mycobacterium tuberculosis stressed out? A critical assessment of the genetic evidence. Microbes Infect 2010; 12:1091-101. [PMID: 20691805 PMCID: PMC3587153 DOI: 10.1016/j.micinf.2010.07.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 07/27/2010] [Indexed: 11/17/2022]
Abstract
Mycobacterium tuberculosis is an obligate human intracellular pathogen which remains a major killer worldwide. A remarkable feature of M. tuberculosis infection is the ability of the pathogen to persist within the host for decades despite an impressive onslaught of stresses. In this review we seek to outline the host-inflicted stresses experienced by M. tuberculosis, the bacterial strategies used to withstand these stresses, and how this information should guide our efforts to combat this global pathogen.
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Affiliation(s)
- Christina L Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Castellanos E, Romero B, Rodríguez S, de Juan L, Bezos J, Mateos A, Domínguez L, Aranaz A. Molecular characterization of Mycobacterium avium subspecies paratuberculosis Types II and III isolates by a combination of MIRU-VNTR loci. Vet Microbiol 2010; 144:118-26. [PMID: 20116185 DOI: 10.1016/j.vetmic.2009.12.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Revised: 12/16/2009] [Accepted: 12/21/2009] [Indexed: 11/19/2022]
Abstract
Mycobacterial interspersed repetitive units and variable number tandem repeats typing (MIRU-VNTR) is a useful technique that has been recently applied to characterize members of the Mycobacterium avium complex (MAC). The aim of this study was to examine the genetic variability among a collection of Spanish M. avium subspecies paratuberculosis (M. a. paratuberculosis) isolates with a combination of MIRU-VNTR loci. For this purpose we tested six MIRU-VNTR loci (MIRU-2, MIRU-3, VNTR-25, VNTR-32, VNTR-292 and VNTR-259) in 70 M. a. paratuberculosis isolates of Types II and III that were recovered from 22 Spanish localities during a nine-year period (1998-2007). The combination of five loci (MIRU-2, MIRU-3, VNTR-25, VNTR-32 and VNTR-259) enabled the differentiation of 12 allelic profiles, with a resulting Hunter and Gaston discriminatory index (HGDI) of 0.84. Moreover, we obtained MIRU-VNTR patterns that were unique for each of the M. a. paratuberculosis types analyzed (II and III); other patterns were host-related or restricted to geographic areas. Therefore, this MIRU-VNTR approach could be a useful sub-typing molecular tool in order to get a better sense of the epidemiology of Johne's disease.
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Affiliation(s)
- Elena Castellanos
- Centro de Vigilancia Sanitaria Veterinaria VISAVET, Universidad Complutense de Madrid, Avda Puerta de Hierro, 28040 Madrid, Spain
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Beste DJV, Espasa M, Bonde B, Kierzek AM, Stewart GR, McFadden J. The genetic requirements for fast and slow growth in mycobacteria. PLoS One 2009; 4:e5349. [PMID: 19479006 PMCID: PMC2685279 DOI: 10.1371/journal.pone.0005349] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 03/31/2009] [Indexed: 01/14/2023] Open
Abstract
Mycobacterium tuberculosis infects a third of the world's population. Primary tuberculosis involving active fast bacterial replication is often followed by asymptomatic latent tuberculosis, which is characterised by slow or non-replicating bacteria. Reactivation of the latent infection involving a switch back to active bacterial replication can lead to post-primary transmissible tuberculosis. Mycobacterial mechanisms involved in slow growth or switching growth rate provide rational targets for the development of new drugs against persistent mycobacterial infection. Using chemostat culture to control growth rate, we screened a transposon mutant library by Transposon site hybridization (TraSH) selection to define the genetic requirements for slow and fast growth of Mycobacterium bovis (BCG) and for the requirements of switching growth rate. We identified 84 genes that are exclusively required for slow growth (69 hours doubling time) and 256 genes required for switching from slow to fast growth. To validate these findings we performed experiments using individual M. tuberculosis and M. bovis BCG knock out mutants. We have demonstrated that growth rate control is a carefully orchestrated process which requires a distinct set of genes encoding several virulence determinants, gene regulators, and metabolic enzymes. The mce1 locus appears to be a component of the switch to slow growth rate, which is consistent with the proposed role in virulence of M. tuberculosis. These results suggest novel perspectives for unravelling the mechanisms involved in the switch between acute and persistent TB infections and provide a means to study aspects of this important phenomenon in vitro.
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Affiliation(s)
| | - Mateus Espasa
- FHMS, University of Surrey, Guildford, United Kingdom
| | - Bhushan Bonde
- FHMS, University of Surrey, Guildford, United Kingdom
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He YW, Boon C, Zhou L, Zhang LH. Co-regulation ofXanthomonas campestrisvirulence by quorum sensing and a novel two-component regulatory system RavS/RavR. Mol Microbiol 2009; 71:1464-76. [DOI: 10.1111/j.1365-2958.2009.06617.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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44
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Buettner FFR, Bendallah IM, Bosse JT, Dreckmann K, Nash JHE, Langford PR, Gerlach GF. Analysis of the Actinobacillus pleuropneumoniae ArcA regulon identifies fumarate reductase as a determinant of virulence. Infect Immun 2008; 76:2284-95. [PMID: 18378638 PMCID: PMC2423083 DOI: 10.1128/iai.01540-07] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 01/10/2008] [Accepted: 03/23/2008] [Indexed: 11/20/2022] Open
Abstract
The ability of the bacterial pathogen Actinobacillus pleuropneumoniae to grow anaerobically allows the bacterium to persist in the lung. The ArcAB two-component system is crucial for metabolic adaptation in response to anaerobic conditions, and we recently showed that an A. pleuropneumoniae arcA mutant had reduced virulence compared to the wild type (F. F. Buettner, A. Maas, and G.-F. Gerlach, Vet. Microbiol. 127:106-115, 2008). In order to understand the attenuated phenotype, we investigated the ArcA regulon of A. pleuropneumoniae by using a combination of transcriptome (microarray) and proteome (two-dimensional difference gel electrophoresis and subsequent mass spectrometry) analyses. We show that ArcA negatively regulates the expression of many genes, including those encoding enzymes which consume intermediates during fumarate synthesis. Simultaneously, the expression of glycerol-3-phosphate dehydrogenase, a component of the respiratory chain serving as a direct reduction equivalent for fumarate reductase, was upregulated. This result, together with the in silico analysis finding that A. pleuropneumoniae has no oxidative branch of the citric acid cycle, led to the hypothesis that fumarate reductase might be crucial for virulence by providing (i) energy via fumarate respiration and (ii) succinate and other essential metabolic intermediates via the reductive branch of the citric acid cycle. To test this hypothesis, an isogenic A. pleuropneumoniae fumarate reductase deletion mutant was constructed and studied by using a pig aerosol infection model. The mutant was shown to be significantly attenuated, thereby strongly supporting a crucial role for fumarate reductase in the pathogenesis of A. pleuropneumoniae infection.
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Affiliation(s)
- Falk F R Buettner
- Department of Infectious Diseases, Institute for Microbiology, University of Veterinary Medicine Hannover, Hannover, Germany
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45
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Kendall SL, Withers M, Soffair CN, Moreland NJ, Gurcha S, Sidders B, Frita R, ten Bokum A, Besra GS, Lott JS, Stoker NG. A highly conserved transcriptional repressor controls a large regulon involved in lipid degradation in Mycobacterium smegmatis and Mycobacterium tuberculosis. Mol Microbiol 2007; 65:684-99. [PMID: 17635188 PMCID: PMC1995591 DOI: 10.1111/j.1365-2958.2007.05827.x] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Mycobacterium tuberculosis TetR-type regulator Rv3574 has been implicated in pathogenesis as it is induced in vivo, and genome-wide essentiality studies show it is required for infection. As the gene is highly conserved in the mycobacteria, we deleted the Rv3574 orthologue in Mycobacterium smegmatis (MSMEG_6042) and used real-time quantitative polymerase chain reaction and microarray analyses to show that it represses the transcription both of itself and of a large number of genes involved in lipid metabolism. We identified a conserved motif within its own promoter (TnnAACnnGTTnnA) and showed that it binds as a dimer to 29 bp probes containing the motif. We found 16 and 31 other instances of the motif in intergenic regions of M. tuberculosis and M. smegmatis respectively. Combining the results of the microarray studies with the motif analyses, we predict that Rv3574 directly controls the expression of 83 genes in M. smegmatis, and 74 in M. tuberculosis. Many of these genes are known to be induced by growth on cholesterol in rhodococci, and palmitate in M. tuberculosis. We conclude that this regulator, designated elsewhere as kstR, controls the expression of genes used for utilizing diverse lipids as energy sources, possibly imported through the mce4 system.
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Affiliation(s)
- Sharon L Kendall
- Department of Pathology and Infectious Diseases, The Royal Veterinary CollegeRoyal College Street, London NW1 0TU, UK.
| | - Mike Withers
- Department of Pathology and Infectious Diseases, The Royal Veterinary CollegeRoyal College Street, London NW1 0TU, UK.
| | - Catherine N Soffair
- Department of Pathology and Infectious Diseases, The Royal Veterinary CollegeRoyal College Street, London NW1 0TU, UK.
| | - Nicole J Moreland
- Laboratory of Structural Biology and Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of AucklandAuckland, New Zealand.
| | - Sudagar Gurcha
- School of Biosciences, University of Birmingham, EdgbastonBirmingham B15 2TT, UK.
| | - Ben Sidders
- Department of Pathology and Infectious Diseases, The Royal Veterinary CollegeRoyal College Street, London NW1 0TU, UK.
| | - Rosangela Frita
- Department of Pathology and Infectious Diseases, The Royal Veterinary CollegeRoyal College Street, London NW1 0TU, UK.
| | - Annemieke ten Bokum
- Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical MedicineLondon WC1E 7HT, UK.
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, EdgbastonBirmingham B15 2TT, UK.
| | - J Shaun Lott
- Laboratory of Structural Biology and Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, University of AucklandAuckland, New Zealand.
| | - Neil G Stoker
- Department of Pathology and Infectious Diseases, The Royal Veterinary CollegeRoyal College Street, London NW1 0TU, UK.
- For correspondence. E-mail: ; Tel. (+020) 7468 5272; Fax (+020) 7468 5306
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Wehenkel A, Bellinzoni M, Graña M, Duran R, Villarino A, Fernandez P, Andre-Leroux G, England P, Takiff H, Cerveñansky C, Cole ST, Alzari PM. Mycobacterial Ser/Thr protein kinases and phosphatases: physiological roles and therapeutic potential. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1784:193-202. [PMID: 17869195 DOI: 10.1016/j.bbapap.2007.08.006] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 08/01/2007] [Accepted: 08/03/2007] [Indexed: 11/19/2022]
Abstract
Reversible protein phosphorylation is a major regulation mechanism of fundamental biological processes, not only in eukaryotes but also in bacteria. A growing body of evidence suggests that Ser/Thr phosphorylation play important roles in the physiology and virulence of Mycobacterium tuberculosis, the etiological agent of tuberculosis. This pathogen uses 'eukaryotic-like' Ser/Thr protein kinases and phosphatases not only to regulate many intracellular metabolic processes, but also to interfere with signaling pathways of the infected host cell. Disrupting such processes by means of selective inhibitors may thus provide new pharmaceutical weapons to combat the disease. Here we review the current knowledge on Ser/Thr protein kinases and phosphatases in M. tuberculosis, their regulation mechanisms and putative substrates, and we explore their therapeutic potential as possible targets for the development of new anti-mycobacterial compounds.
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Affiliation(s)
- Annemarie Wehenkel
- Unité de Biochimie Structurale, URA 2185 CNRS, Institut Pasteur, 25 rue du Docteur Roux, F-75724, Paris Cedex 15, France
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47
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Glover RT, Kriakov J, Garforth SJ, Baughn AD, Jacobs WR. The two-component regulatory system senX3-regX3 regulates phosphate-dependent gene expression in Mycobacterium smegmatis. J Bacteriol 2007; 189:5495-503. [PMID: 17526710 PMCID: PMC1951828 DOI: 10.1128/jb.00190-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Phosphate import is required for the growth of mycobacteria and is regulated by environmental inorganic phosphate (P(i)) concentrations, although the mechanism of this regulation has not been characterized. The expression of genes involved in P(i) acquisition is frequently regulated by two-component regulatory systems (2CRs) consisting of a sensor histidine kinase and a DNA-binding response regulator. In this work, we have identified the senX3-regX3 2CR as a P(i)-dependent regulator of genes involved in phosphate acquisition in Mycobacterium smegmatis. Characterization of senX3 mutants with different PhoA phenotypes suggests a dual role for SenX3 as a phosphatase or a phosphodonor for the response regulator RegX3, depending upon P(i) availability. Expression of PhoA activity required phosphorylation of RegX3, consistent with a role for phosphorylated RegX3 (RegX3 approximately P) as a transcriptional activator of phoA. Furthermore, purified RegX3 approximately P bound to promoter sequences from phoA, senX3, and the high-affinity phosphate transporter component pstS, demonstrating direct transcriptional control of all three genes. DNase I footprinting and primer extension analyses have further defined the DNA-binding region and transcriptional start site within the phoA promoter. A DNA motif consisting of an inverted repeat was identified in each of the promoters bound by RegX3 approximately P. Based upon our findings, we propose a model for P(i)-regulated gene expression mediated by SenX3-RegX3 in mycobacteria.
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Affiliation(s)
- Robert T Glover
- Howard Hughes Medical Institute, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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48
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Janin YL. Antituberculosis drugs: ten years of research. Bioorg Med Chem 2007; 15:2479-513. [PMID: 17291770 DOI: 10.1016/j.bmc.2007.01.030] [Citation(s) in RCA: 360] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 12/26/2006] [Accepted: 01/17/2007] [Indexed: 02/03/2023]
Abstract
Tuberculosis is today amongst the worldwide health threats. As resistant strains of Mycobacterium tuberculosis have slowly emerged, treatment failure is too often a fact, especially in countries lacking the necessary health care organisation to provide the long and costly treatment adapted to patients. Because of lack of treatment or lack of adapted treatment, at least two million people will die of tuberculosis this year. Due to this concern, this infectious disease was the focus of renewed scientific interest in the last decade. Regimens were optimized and much was learnt on the mechanisms of action of the antituberculosis drugs used. Moreover, the quest for original drugs overcoming some of the problems of current regimens also became the focus of research programmes and many new series of M. tuberculosis growth inhibitors were reported. This review presents the drugs currently used in antituberculosis treatments and the most advanced compounds undergoing clinical trials. We then provide a description of their mechanism of action along with other series of inhibitors known to act on related biochemical targets. This is followed by other inhibitors of M. tuberculosis growth, including recently reported compounds devoid of a reported mechanism of action.
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Affiliation(s)
- Yves L Janin
- URA 2128 CNRS-Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
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Tucker PA, Nowak E, Morth JP. Two-component systems of Mycobacterium tuberculosis: structure-based approaches. Methods Enzymol 2007; 423:479-501. [PMID: 17609147 DOI: 10.1016/s0076-6879(07)23023-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Mycobacterium tuberculosis contains few two-component systems compared to many other bacteria, possibly because it has more serine/threonine signaling pathways. Even so, these two-component systems appear to play an important role in early intracellular survival of the pathogen as well as in aspects of virulence. In this chapter, we discuss what has been learned about the mycobacterial two-component systems, with particular emphasis on knowledge gained from structural genomics projects.
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Affiliation(s)
- Paul A Tucker
- Hamburg Outstation, European Molecular Biology Laboratory (EMBL), Hamburg, Germany
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50
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Pei Y, Parreira V, Nicholson VM, Prescott JF. Mutation and virulence assessment of chromosomal genes of Rhodococcus equi 103. CANADIAN JOURNAL OF VETERINARY RESEARCH = REVUE CANADIENNE DE RECHERCHE VETERINAIRE 2007; 71:1-7. [PMID: 17193875 PMCID: PMC1636002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Rhodococcus equi can cause severe or fatal pneumonia in foals as well as in immunocompromised animals and humans. Its ability to persist in macrophages is fundamental to how it causes disease, but the basis of this is poorly understood. To examine further the general application of a recently developed system of targeted gene mutation and to assess the importance of different genes in resistance to innate immune defenses, we disrupted the genes encoding high-temperature requirement A (htrA), nitrate reductase (narG), peptidase D (pepD), phosphoribosylaminoimidazole-succinocarboxamide synthase (purC), and superoxide dismutase (sodC) in strain 103 of R. equi using a double-crossover homologous recombination approach. Virulence testing by clearance after intravenous injection in mice showed that the htrA and narG mutants were fully attenuated, the purC and sodC mutants were unchanged, and the pepD mutant was slightly attenuated. Complementation with the pREM shuttle plasmid restored the virulence of the htrA and pepD mutants but not that of the narG mutant. A single-crossover mutation approach was simpler and faster than the double-crossover homologous recombination technique and was used to obtain mutations in 6 other genes potentially involved in virulence (clpB, fadD8, fbpB, glnA1, regX3, and sigF). These mutants were not attenuated in the mouse clearance assay. We were not able to obtain mutants for genesfurA, galE, and sigE using the single-crossover mutation approach. In summary, the targeted-mutation system had general applicability but was not always completely successful, perhaps because some genes are essential under the growth conditions used or because the success of mutation depends on the target genes.
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Affiliation(s)
| | | | | | - John F. Prescott
- Address all correspondence and reprint requests to Dr. John F. Prescott; telephone: (519) 824-4120, ext. 54453; fax: (519) 824-5930; e-mail:
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