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Singh P, Kumar A, Chhabra R, Singh K, Kaur J. MSMEG_5850, a stress-induced TetR protein, involved in global transcription regulation in Mycobacterium smegmatis. Future Microbiol 2023; 18:563-580. [PMID: 37284769 DOI: 10.2217/fmb-2022-0238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023] Open
Abstract
Aim: To decipher the role of MSMEG_5850 in the physiology of mycobacteria. Methods: MSMEG_5850 was knocked out and RNA sequencing was performed. MSMEG_5850 protein was purified from the Escherichia coli pET28a system. Electrophoretic mobility shift assay and size exclusion chromatography were used to determine the binding of MSMEG_5850 to its motif and binding stoichiometry. The effect of nutritional stress was monitored. Results: Transcriptome analysis revealed the differential expression of 148 genes in an MSMEG_5850 knockout strain. MSMEG_5850 had control over 50 genes because those genes had a binding motif upstream of their sequence. The electrophoretic mobility shift assay showed MSMEG_5850 bound to its motif as a monomer. MSMEG_5850 was upregulated under nutritional stress and promoted the survival of mycobacteria. Conclusion: The study confirms the role of MSMEG_5850 in global transcriptional regulation.
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Affiliation(s)
- Parul Singh
- Department of Biotechnology, BMS Block-1, Sector-25, Panjab University, Chandigarh, 160014, India
| | - Arbind Kumar
- Department of Biotechnology, BMS Block-1, Sector-25, Panjab University, Chandigarh, 160014, India
- Current Address: Fellow Scientist, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India
| | - Ravindresh Chhabra
- Department of Biochemistry, Central University of Punjab, Bathinda, 151001, India
| | - Kashmir Singh
- Department of Biotechnology, BMS Block-1, Sector-25, Panjab University, Chandigarh, 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, BMS Block-1, Sector-25, Panjab University, Chandigarh, 160014, India
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Yang M, Jia SH, Tao HL, Zhu C, Jia WZ, Hu LH, Gao CH. Cd(II)-binding transcriptional regulator interacts with isoniazid and regulates drug susceptibility in mycobacteria. J Biochem 2021; 169:43-53. [PMID: 32706888 DOI: 10.1093/jb/mvaa086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 07/16/2020] [Indexed: 02/03/2023] Open
Abstract
It is urgent to understand the regulatory mechanism of drug resistance in widespread bacterial pathogens. In Mycobacterium tuberculosis, several transcriptional regulators have been found to play essential roles in regulating its drug resistance. In this study, we found that an ArsR family transcription regulator encoded by Rv2642 (CdiR) responds to isoniazid (INH), a widely used anti-tuberculosis (TB) drug. CdiR negatively regulates self and adjacent genes, including arsC (arsenic-transport integral membrane protein ArsC). CdiR directly interacts with INH and Cd(II). The binding of INH and Cd(II) both reduce its DNA-binding activity. Disrupting cdiR increased the drug susceptibility to INH, whereas overexpressing cdiR decreased the susceptibility. Strikingly, overexpressing arsC increased the drug susceptibility as well as cdiR. Additionally, both changes in cdiR and arsC expression caused sensitivity to other drugs such as rifamycin and ethambutol, where the minimal inhibitory concentrations in the cdiR deletion strain were equal to those of the arsC-overexpressing strain, suggesting that the function of CdiR in regulating drug resistance primarily depends on arsC. Furthermore, we found that Cd(II) enhances bacterial resistance to INH in a CdiR-dependent manner. As a conclusion, CdiR has a critical role in directing the interplay between Cd(II) metal ions and drug susceptibility in mycobacteria.
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Affiliation(s)
- Min Yang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shi-Hua Jia
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui-Ling Tao
- International Agricultural Institute, Yunnan Academy of Agricultural Sciences, Kunming 650224, China
| | - Chen Zhu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wan-Zhong Jia
- The State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Li-Hua Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chun-Hui Gao
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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Zhu C, Liu Y, Hu L, Yang M, He ZG. Molecular mechanism of the synergistic activity of ethambutol and isoniazid against Mycobacterium tuberculosis. J Biol Chem 2018; 293:16741-16750. [PMID: 30185616 DOI: 10.1074/jbc.ra118.002693] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 08/26/2018] [Indexed: 11/06/2022] Open
Abstract
Isoniazid (INH) and ethambutol (EMB) are two major first-line drugs for managing tuberculosis (TB), caused by the microbe Mycobacterium tuberculosis Although co-use of these two drugs is common in clinical practice, the mechanism for the potential synergistic interplay between them remains unclear. Here, we present first evidence that INH and EMB act synergistically through a transcriptional repressor of the inhA gene, the target gene of INH encoding an enoyl-acyl carrier protein reductase of the fatty acid synthase type II system required for bacterial cell wall integrity. We report that EMB binds a hypothetical transcription factor encoded by the Rv0273c gene, designated here as EtbR. Using DNA footprinting, we found that EtbR specifically recognizes a motif sequence in the upstream region of the inhA gene. Using isothermal titration calorimetry and surface plasmon resonance assays, we observed that EMB binds EtbR in a 1:1 ratio and thereby stimulates its DNA-binding activity. When a nonlethal dose of EMB was delivered in combination with INH, EMB increased the INH susceptibility of cultured M. tuberculosis cells. In summary, EMB induces EtbR-mediated repression of inhA and thereby enhances the mycobactericidal effect of INH. Our findings uncover a molecular mechanism for the synergistic activity of two important anti-TB drugs.
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Affiliation(s)
- Chen Zhu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yu Liu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lihua Hu
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Min Yang
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Zheng-Guo He
- From the National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
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Zer H, Margulis K, Georg J, Shotland Y, Kostova G, Sultan LD, Hess WR, Keren N. Resequencing of a mutant bearing an iron starvation recovery phenotype defines Slr1658 as a new player in the regulatory network of a model cyanobacterium. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:235-245. [PMID: 29161470 DOI: 10.1111/tpj.13770] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 06/07/2023]
Abstract
Photosynthetic microorganisms encounter an erratic nutrient environment characterized by periods of iron limitation and sufficiency. Surviving in such an environment requires mechanisms for handling these transitions. Our study identified a regulatory system involved in the process of recovery from iron limitation in cyanobacteria. We set out to study the role of bacterioferritin co-migratory proteins during transitions in iron bioavailability in the cyanobacterium Synechocystis sp. PCC 6803 using knockout strains coupled with physiological and biochemical measurements. One of the mutants displayed slow recovery from iron limitation. However, we discovered that the cause of the phenotype was not the intended knockout but rather the serendipitous selection of a mutation in an unrelated locus, slr1658. Bioinformatics analysis suggested similarities to two-component systems and a possible regulatory role. Transcriptomic analysis of the recovery from iron limitation showed that the slr1658 mutation had an extensive effect on the expression of genes encoding regulatory proteins, proteins involved in the remodeling and degradation of the photosynthetic apparatus and proteins modulating electron transport. Most significantly, expression of the cyanobacterial homologue of the cyclic electron transport protein PGR5 was upregulated 1000-fold in slr1658 disruption mutants. pgr5 transcripts in the Δslr1658 mutant retained these high levels under a range of stress and recovery conditions. The results suggest that slr1658 is part of a regulatory operon that, among other aspects, affects the regulation of alternative electron flow. Disruption of its function has deleterious results under oxidative stress promoting conditions.
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Affiliation(s)
- Hagit Zer
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Ketty Margulis
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Jens Georg
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Yoram Shotland
- Department of Chemical Engineering, Shamoon College of Engineering, Beer Sheva, 84100, Israel
| | - Gergana Kostova
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
| | - Laure D Sultan
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Wolfgang R Hess
- Faculty of Biology, Genetics and Experimental Bioinformatics, University of Freiburg, Schänzlestr. 1, D-79104, Freiburg, Germany
- Freiburg Institute for Advanced Studies, University of Freiburg, Albertstr. 19, D-79104, Freiburg, Germany
| | - Nir Keren
- Department of Plant and Environmental Sciences, Edmond J. Safra Campus, The Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
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Mycobacterium tuberculosis Rv1474c is a TetR-like transcriptional repressor that regulates aconitase, an essential enzyme and RNA-binding protein, in an iron-responsive manner. Tuberculosis (Edinb) 2017; 103:71-82. [PMID: 28237036 DOI: 10.1016/j.tube.2017.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/04/2017] [Accepted: 01/15/2017] [Indexed: 11/21/2022]
Abstract
Mycobacterium tuberculosis (M.tb), tuberculosis (TB) causing bacteria, employs several mechanisms to maintain iron homeostasis which is critical for its survival and pathogenesis. M.tb aconitase (Acn), a [4Fe-4S] cluster-containing essential protein, apart from participating in energy cycle, also binds to predicted iron-responsive RNA elements. In this study, we identified Rv1474c as a regulator of its operonic partner acn and carried out its biochemical and functional characterization. The binding motif for Rv1474c in the upstream region of acn (Rv1475c)-Rv1474c operon was verified by gel-shift assays. Reporter assays in E. coli followed by over-expression studies in mycobacteria, using both wild type and a DNA-binding defective mutant, demonstrated Rv1474c as a Tet-R like repressor of acn. Rv1474c, besides binding tetracycline, could also bind iron which negatively influenced its DNA binding activity. Further, a consistent decrease in the relative transcript levels of acn when M.tb was grown in iron-deficient conditions as compared to either normal or other stress conditions, indicated regulation of acn by Rv1474c in an iron-responsive manner in vivo. The absence of homologs in the human host and its association with indispensable iron homeostasis makes Rv1474c an attractive target for designing novel anti-mycobacterials.
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Sdt97: A Point Mutation in the 5' Untranslated Region Confers Semidwarfism in Rice. G3-GENES GENOMES GENETICS 2016; 6:1491-502. [PMID: 27172200 PMCID: PMC4889646 DOI: 10.1534/g3.116.028720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Semidwarfism is an important agronomic trait in rice breeding programs. The semidwarf mutant gene Sdt97 was previously described. However, the molecular mechanism underlying the mutant is yet to be elucidated. In this study, we identified the mutant gene by a map-based cloning method. Using a residual heterozygous line (RHL) population, Sdt97 was mapped to the long arm of chromosome 6 in the interval of nearly 60 kb between STS marker N6 and SNP marker N16 within the PAC clone P0453H04. Sequencing of the candidate genes in the target region revealed that a base transversion from G to C occurred in the 5′ untranslated region of Sdt97. qRT-PCR results confirmed that the transversion induced an obvious change in the expression pattern of Sdt97 at different growth and developmental stages. Plants transgenic for Sdt97 resulted in the restoration of semidwarfism of the mutant phenotype, or displayed a greater dwarf phenotype than the mutant. Our results indicate that a point mutation in the 5′ untranslated region of Sdt97 confers semidwarfism in rice. Functional analysis of Sdt97 will open a new field of study for rice semidwarfism, and also expand our knowledge of the molecular mechanism of semidwarfism in rice.
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Balhana RJC, Singla A, Sikder MH, Withers M, Kendall SL. Global analyses of TetR family transcriptional regulators in mycobacteria indicates conservation across species and diversity in regulated functions. BMC Genomics 2015; 16:479. [PMID: 26115658 PMCID: PMC4482099 DOI: 10.1186/s12864-015-1696-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 06/12/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mycobacteria inhabit diverse niches and display high metabolic versatility. They can colonise both humans and animals and are also able to survive in the environment. In order to succeed, response to environmental cues via transcriptional regulation is required. In this study we focused on the TetR family of transcriptional regulators (TFTRs) in mycobacteria. RESULTS We used InterPro to classify the entire complement of transcriptional regulators in 10 mycobacterial species and these analyses showed that TFTRs are the most abundant family of regulators in all species. We identified those TFTRs that are conserved across all species analysed and those that are unique to the pathogens included in the analysis. We examined genomic contexts of 663 of the conserved TFTRs and observed that the majority of TFTRs are separated by 200 bp or less from divergently oriented genes. Analyses of divergent genes indicated that the TFTRs control diverse biochemical functions not limited to efflux pumps. TFTRs typically bind to palindromic motifs and we identified 11 highly significant novel motifs in the upstream regions of divergently oriented TFTRs. The C-terminal ligand binding domain from the TFTR complement in M. tuberculosis showed great diversity in amino acid sequence but with an overall architecture common to other TFTRs. CONCLUSION This study suggests that mycobacteria depend on TFTRs for the transcriptional control of a number of metabolic functions yet the physiological role of the majority of these regulators remain unknown.
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Affiliation(s)
- Ricardo J C Balhana
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Royal College street, Camden, London, NW1 OTU, UK. .,Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford, GU2 7XH, UK.
| | - Ashima Singla
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Royal College street, Camden, London, NW1 OTU, UK. .,Indian Institute of Technology Kanpur, Kanpur, India.
| | - Mahmudul Hasan Sikder
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Royal College street, Camden, London, NW1 OTU, UK. .,Department of Pharmacology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.
| | - Mike Withers
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Royal College street, Camden, London, NW1 OTU, UK.
| | - Sharon L Kendall
- Department of Pathology and Pathogen Biology, The Royal Veterinary College, Royal College street, Camden, London, NW1 OTU, UK.
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Pan T, Huang P, Xiong G, Maser E. Isolation and identification of a repressor TetR for 3,17β-HSD expressional regulation in Comamonas testosteroni. Chem Biol Interact 2015; 234:205-12. [PMID: 25559855 DOI: 10.1016/j.cbi.2014.12.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/14/2014] [Accepted: 12/18/2014] [Indexed: 11/16/2022]
Abstract
Comamonas testosteroni (C. testosteroni) is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons. 3,17β-Hydroxysteroid dehydrogenase (3,17β-HSD) from C. testosteroni is a key enzyme in steroid degradation. Understanding the mechanism of 3,17β-HSD gene (βhsd) induction may help us to elucidate its complete molecular regulation. Sequencing the C. testosteroni ATCC11996 genome lead us to identify the tetR (522 bp) downstream of βhsd. Two repeat sequences (RS; 13 bp), that are separated to each other by 1661 bp, were found upstream of βhsd. A bioinformatic analysis revealed that TetR family proteins act as transcriptional repressors which are sensitive to environmental signals. Since, C. testosteroni responds to environmental steroid induction and upregulates steroid catabolic genes, we hypothesized that TetR might act in C. testosteroni as repressor for βhsd expression. The tetR was cloned into different plasmids, including an EGFP reporter system, for functional characterization and/or overexpression. The data indicate that, indeed, TetR acts as a repressor for 3,17β-HSD expression. Testosterone in turn, which is known to induce βhsd expression, could not resolve TetR repression. To further substantiate TetR as repressor for βhsd expression, a tetR gene knock-out mutant of C. testosteroni was generated. TetR gene knock-out mutants showed the same basal low level of βhsd expression as the C. testosteroni wild type cells. Interestingly, testosterone induction leads to a strong increase in βhsd expression, especially in the tetR gene knock-out mutants. The result with the knock-out mutant, in principle, supports our hypothesis that TetR is a repressor for βhsd expression, but the exact role of testosterone in this context remains unknown. Finally, it turned out that TetR is obviously also involved in the regulation of the hsdA gene.
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Affiliation(s)
- Tianyuan Pan
- Institute of Toxicology and Pharmacology for Natural Scientists, Medical School Schleswig-Holstein, Kiel, Germany; Department of Family Medicine, The First Affiliated Hospital, School of Medicine, Zhejiang University, 310000 Hangzhou, China
| | - Pu Huang
- Department of Biochemistry and Genetics, School of Medicine, Zhejiang University, 310058 Hangzhou, China
| | - Guangming Xiong
- Institute of Toxicology and Pharmacology for Natural Scientists, Medical School Schleswig-Holstein, Kiel, Germany
| | - Edmund Maser
- Institute of Toxicology and Pharmacology for Natural Scientists, Medical School Schleswig-Holstein, Kiel, Germany.
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