1
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Arejan NH, Czapski DR, Buonomo JA, Boutte CC. MmpL3, Wag31, and PlrA are involved in coordinating polar growth with peptidoglycan metabolism and nutrient availability. J Bacteriol 2024; 206:e0020424. [PMID: 39320104 PMCID: PMC11500546 DOI: 10.1128/jb.00204-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 07/23/2024] [Indexed: 09/26/2024] Open
Abstract
Cell growth in mycobacteria involves cell wall expansion that is restricted to the cell poles. The DivIVA homolog Wag31 is required for this process, but the molecular mechanism and protein partners of Wag31 have not been described. In this study of Mycobacterium smegmatis, we identify a connection between wag31 and trehalose monomycolate (TMM) transporter mmpl3 in a suppressor screen and show that Wag31 and polar regulator PlrA are required for MmpL3's polar localization. In addition, the localization of PlrA and MmpL3 is responsive to nutrient and energy deprivation and inhibition of peptidoglycan metabolism. We show that inhibition of MmpL3 causes delocalized cell wall metabolism but does not delocalize MmpL3 itself. We found that cells with an MmpL3 C-terminal truncation, which is defective for localization, have only minor defects in polar growth but are impaired in their ability to downregulate cell wall metabolism under stress. Our work suggests that, in addition to its established function in TMM transport, MmpL3 has a second function in regulating global cell wall metabolism in response to stress. Our data are consistent with a model in which the presence of TMMs in the periplasm stimulates polar elongation and in which the connection between Wag31, PlrA, and the C-terminus of MmpL3 is involved in detecting and responding to stress in order to coordinate the synthesis of the different layers of the mycobacterial cell wall in changing conditions. IMPORTANCE This study is performed in Mycobacterium smegmatis, which is used as a model to understand the basic physiology of pathogenic mycobacteria such as Mycobacterium tuberculosis. In this work, we examine the function and regulation of three proteins involved in regulating cell wall elongation in mycobacterial cells, which occurs at the cell tips or poles. We find that Wag31, a regulator of polar elongation, works partly through the regulation of MmpL3, a transporter of cell wall constituents and an important drug target. Our work suggests that, beyond its transport function, MmpL3 has another function in controlling cell wall synthesis broadly in response to stress.
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Affiliation(s)
| | - Desiree R. Czapski
- Department of Chemistry and Biochemistry, University of Texas, Arlington, Texas, USA
| | - Joseph A. Buonomo
- Department of Chemistry and Biochemistry, University of Texas, Arlington, Texas, USA
| | - Cara C. Boutte
- Department of Biology, University of Texas, Arlington, Texas, USA
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2
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Zhao H, Li J, Feng S, Xu L, Yan B, Li C, Li M, Wang Y, Li Y, Liang L, Zhou D, Wan J, Wang W, Tian GB, Gu B, Huang X. High-throughput mutagenesis and screening approach for the identification of drug-resistant mutations in the rifampicin resistance-determining region of mycobacteria. Int J Antimicrob Agents 2024; 63:107158. [PMID: 38537722 DOI: 10.1016/j.ijantimicag.2024.107158] [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] [Received: 10/30/2023] [Revised: 02/05/2024] [Accepted: 03/22/2024] [Indexed: 05/31/2024]
Abstract
Rifampicin is the most powerful first-line antibiotic for tuberculosis, which is caused by Mycobacterium tuberculosis. Although accumulating evidence from sequencing data of clinical M. tuberculosis isolates suggested that mutations in the rifampicin-resistance-determining region (RRDR) are strongly associated with rifampicin resistance, the comprehensive characterisation of RRDR polymorphisms that confer this resistance remains challenging. By incorporating I-SceI sites for I-SceI-based integrant removal and utilizing an L5 swap strategy, we efficiently replaced the integrated plasmid with alternative alleles, making mass allelic exchange feasible in mycobacteria. Using this method to establish a fitness-related gain-of function screen, we generated a mutant library that included all single-amino-acid mutations in the RRDR, and identified the important positions corresponding to some well-known rifampicin-resistance mutations (Q513, D516, S522, H525, R529, S531). We also detected a novel two-point mutation located in the RRDR confers a fitness advantage to M. smegmatis in the presence or absence of rifampicin. Our method provides a comprehensive insight into the growth phenotypes of RRDR mutants and should facilitate the development of anti-tuberculosis drugs.
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Affiliation(s)
- Hui Zhao
- Guangdong Cardiovascular Institute, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510000, China; Department of Clinical Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510000, China
| | - Jiachen Li
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Siyuan Feng
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Lin Xu
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Bin Yan
- Department of Neonatal Surgery, Guangzhou Women and Children's Medical Center, Guangzhou 510080, China
| | - Chengjuan Li
- School of Basic Medical Sciences, Xizang Minzu University, Xianyang, 712082, China
| | - Meisong Li
- Department of Clinical Laboratory Medicine, Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China
| | - Yaxuan Wang
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Yaxin Li
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Lujie Liang
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Dianrong Zhou
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Jia Wan
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Wenli Wang
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China
| | - Guo-Bao Tian
- Advanced Medical Technology Center, The First Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Department of Immunology, School of Medicine, Sun Yat-Sen University, Shenzhen 518107, China; State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Program in Pathobiology, The Fifth Affiliated Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangdong, 510080, China; Key Laboratory of Tropical Diseases Control (Sun Yat-sen University), Ministry of Education, Guangzhou 510080, China.
| | - Bing Gu
- Department of Clinical Laboratory Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, 510000, China.
| | - Xi Huang
- Center for Infection and Immunity and Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, 519000, China.
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3
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Won HI, Zinga S, Kandror O, Akopian T, Wolf ID, Schweber JTP, Schmid EW, Chao MC, Waldor M, Rubin EJ, Zhu J. Targeted protein degradation in mycobacteria uncovers antibacterial effects and potentiates antibiotic efficacy. Nat Commun 2024; 15:4065. [PMID: 38744895 PMCID: PMC11094019 DOI: 10.1038/s41467-024-48506-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/03/2024] [Indexed: 05/16/2024] Open
Abstract
Proteolysis-targeting chimeras (PROTACs) represent a new therapeutic modality involving selectively directing disease-causing proteins for degradation through proteolytic systems. Our ability to exploit targeted protein degradation (TPD) for antibiotic development remains nascent due to our limited understanding of which bacterial proteins are amenable to a TPD strategy. Here, we use a genetic system to model chemically-induced proximity and degradation to screen essential proteins in Mycobacterium smegmatis (Msm), a model for the human pathogen M. tuberculosis (Mtb). By integrating experimental screening of 72 protein candidates and machine learning, we find that drug-induced proximity to the bacterial ClpC1P1P2 proteolytic complex leads to the degradation of many endogenous proteins, especially those with disordered termini. Additionally, TPD of essential Msm proteins inhibits bacterial growth and potentiates the effects of existing antimicrobial compounds. Together, our results provide biological principles to select and evaluate attractive targets for future Mtb PROTAC development, as both standalone antibiotics and potentiators of existing antibiotic efficacy.
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Affiliation(s)
- Harim I Won
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Samuel Zinga
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Olga Kandror
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Tatos Akopian
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Ian D Wolf
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Jessica T P Schweber
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Ernst W Schmid
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Blavatnik Institute, Boston, MA, 02115, USA
| | - Michael C Chao
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Maya Waldor
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Eric J Rubin
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
| | - Junhao Zhu
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
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4
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Arejan NH, Czapski DR, Buonomo JA, Boutte CC. MmpL3, Wag31 and PlrA are involved in coordinating polar growth with peptidoglycan metabolism and nutrient availability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.29.591792. [PMID: 38746181 PMCID: PMC11092516 DOI: 10.1101/2024.04.29.591792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Cell growth in mycobacteria involves cell wall expansion that is restricted to the cell poles. The DivIVA homolog Wag31 is required for this process, but the molecular mechanism and protein partners of Wag31 have not been described. In this study of Mycobacterium smegmatis, we identify a connection between wag31 and trehalose monomycolate (TMM) transporter mmpl3 in a suppressor screen, and show that Wag31 and polar regulator PlrA are required for MmpL3's polar localization. In addition, the localization of PlrA and MmpL3 are responsive to nutrient and energy deprivation and inhibition of peptidoglycan metabolism. We show that inhibition of MmpL3 causes delocalized cell wall metabolism, but does not delocalize MmpL3 itself. We found that cells with an MmpL3 C-terminal truncation, which is defective for localization, have only minor defects in polar growth, but are impaired in their ability to downregulate cell wall metabolism under stress. Our work suggests that, in addition to its established function in TMM transport, MmpL3 has a second function in regulating global cell wall metabolism in response to stress. Our data are consistent with a model in which the presence of TMMs in the periplasm stimulates polar elongation, and in which the connection between Wag31, PlrA and the C-terminus of MmpL3 is involved in detecting and responding to stress in order to coordinate synthesis of the different layers of the mycobacterial cell wall in changing conditions.
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Affiliation(s)
| | - Desiree R Czapski
- Department of Chemistry and Biochemistry, University of Texas, Arlington
| | - Joseph A Buonomo
- Department of Chemistry and Biochemistry, University of Texas, Arlington
| | - Cara C Boutte
- Department of Biology, University of Texas, Arlington
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5
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Degiacomi G, Gianibbi B, Recchia D, Stelitano G, Truglio GI, Marra P, Stamilla A, Makarov V, Chiarelli LR, Manetti F, Pasca MR. CanB, a Druggable Cellular Target in Mycobacterium tuberculosis. ACS OMEGA 2023; 8:25209-25220. [PMID: 37483251 PMCID: PMC10357428 DOI: 10.1021/acsomega.3c02311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/05/2023] [Indexed: 07/25/2023]
Abstract
Treatment against tuberculosis can lead to the selection of drug-resistant Mycobacterium tuberculosis strains. To tackle this serious threat, new targets from M. tuberculosis are needed to develop novel effective drugs. In this work, we aimed to provide a possible workflow to validate new targets and inhibitors by combining genetic, in silico, and enzymological approaches. CanB is one of the three M. tuberculosis β-carbonic anhydrases that catalyze the reversible reaction of CO2 hydration to form HCO3- and H+. To this end, we precisely demonstrated that CanB is essential for the survival of the pathogen in vitro by constructing conditional mutants. In addition, to search for CanB inhibitors, conditional canB mutants were also constructed using the Pip-ON system. By molecular docking and minimum inhibitory concentration assays, we selected three molecules that inhibit the growth in vitro of M. tuberculosis wild-type strain and canB conditional mutants, thus implementing a target-to-drug approach. The lead compound also showed a bactericidal activity by the time-killing assay. We further studied the interactions of these molecules with CanB using enzymatic assays and differential scanning fluorimetry thermal shift analysis. In conclusion, the compounds identified by the in silico screening proved to have a high affinity as CanB ligands endowed with antitubercular activity.
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Affiliation(s)
- Giulia Degiacomi
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
| | - Beatrice Gianibbi
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena 53100, Italy
| | - Deborah Recchia
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
| | - Giovanni Stelitano
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
| | | | - Paola Marra
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
| | - Alessandro Stamilla
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
| | - Vadim Makarov
- Bakh
Institute of Biochemistry, Russian Academy
of Science, Moscow 119071, Russia
| | - Laurent Robert Chiarelli
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
| | - Fabrizio Manetti
- Department
of Biotechnology, Chemistry and Pharmacy, University of Siena, Siena 53100, Italy
| | - Maria Rosalia Pasca
- Department
of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Pavia 27100, Italy
- Fondazione
IRCCS Policlinico San Matteo, Pavia 27100, Italy
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6
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Freeman AH, Tembiwa K, Brenner JR, Chase MR, Fortune SM, Morita YS, Boutte CC. Arginine methylation sites on SepIVA help balance elongation and septation in Mycobacterium smegmatis. Mol Microbiol 2023; 119:208-223. [PMID: 36416406 PMCID: PMC10023300 DOI: 10.1111/mmi.15006] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/15/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022]
Abstract
The growth of mycobacterial cells requires successful coordination between elongation and septation. However, it is not clear which factors mediate this coordination. Here, we studied the function and post-translational modification of an essential division factor, SepIVA, in Mycobacterium smegmatis. We find that SepIVA is arginine methylated, and that alteration of its methylation sites affects both septation and polar elongation of Msmeg. Furthermore, we show that SepIVA regulates the localization of MurG and that this regulation may impact polar elongation. Finally, we map SepIVA's two regulatory functions to different ends of the protein: the N-terminus regulates elongation while the C-terminus regulates division. These results establish SepIVA as a regulator of both elongation and division and characterize a physiological role for protein arginine methylation sites for the first time in mycobacteria.
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Affiliation(s)
- Angela H Freeman
- Department of Biology, University of Texas at Arlington,
Arlington, Texas, USA
| | - Karen Tembiwa
- Department of Biology, University of Texas at Arlington,
Arlington, Texas, USA
| | - James R Brenner
- Department of Microbiology, University of Massachusetts,
Amherst, Massachusetts, USA
| | - Michael R Chase
- Department of Immunology and Infectious Disease, Harvard TH
Chan School of Public Health, Boston, Massachusetts, USA
| | - Sarah M Fortune
- Department of Immunology and Infectious Disease, Harvard TH
Chan School of Public Health, Boston, Massachusetts, USA
| | - Yasu S Morita
- Department of Microbiology, University of Massachusetts,
Amherst, Massachusetts, USA
| | - Cara C Boutte
- Department of Biology, University of Texas at Arlington,
Arlington, Texas, USA
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7
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Habibi Arejan N, Ensinck D, Diacovich L, Patel PB, Quintanilla SY, Emami Saleh A, Gramajo H, Boutte CC. Polar protein Wag31 both activates and inhibits cell wall metabolism at the poles and septum. Front Microbiol 2023; 13:1085918. [PMID: 36713172 PMCID: PMC9878328 DOI: 10.3389/fmicb.2022.1085918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 12/20/2022] [Indexed: 01/15/2023] Open
Abstract
Mycobacterial cell elongation occurs at the cell poles; however, it is not clear how cell wall insertion is restricted to the pole or how it is organized. Wag31 is a pole-localized cytoplasmic protein that is essential for polar growth, but its molecular function has not been described. In this study we used alanine scanning mutagenesis to identify Wag31 residues involved in cell morphogenesis. Our data show that Wag31 helps to control proper septation as well as new and old pole elongation. We have identified key amino acid residues involved in these essential functions. Enzyme assays revealed that Wag31 interacts with lipid metabolism by modulating acyl-CoA carboxylase (ACCase) activity. We show that Wag31 does not control polar growth by regulating the localization of cell wall precursor enzymes to the Intracellular Membrane Domain, and we also demonstrate that phosphorylation of Wag31 does not substantively regulate peptidoglycan metabolism. This work establishes new regulatory functions of Wag31 in the mycobacterial cell cycle and clarifies the need for new molecular models of Wag31 function.
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Affiliation(s)
- Neda Habibi Arejan
- Department of Biology, University of Texas at Arlington, Arlington, TX, United States
| | - Delfina Ensinck
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Lautaro Diacovich
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | | | | | - Arash Emami Saleh
- Department of Civil Engineering, University of Texas at Arlington, Arlington, TX, United States
| | - Hugo Gramajo
- Laboratory of Physiology and Genetics of Actinomycetes, Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Cara C. Boutte
- Department of Biology, University of Texas at Arlington, Arlington, TX, United States,*Correspondence: Cara C. Boutte,
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8
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Quintanilla SY, Arejan NH, Patel PB, Boutte CC. PlrA (MSMEG_5223) is an essential polar growth regulator in Mycobacterium smegmatis. PLoS One 2023; 18:e0280336. [PMID: 36634117 PMCID: PMC9836265 DOI: 10.1371/journal.pone.0280336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/27/2022] [Indexed: 01/13/2023] Open
Abstract
Mycobacteria expand their cell walls at the cell poles in a manner that is not well described at the molecular level. In this study, we identify a new polar factor, PlrA, that is involved in restricting peptidoglycan metabolism to the cell poles in Mycobacterium smegmatis. We establish that only the N-terminal membrane domain of PlrA is essential. We show that depletion of plrA pheno-copies depletion of polar growth factor Wag31, and that PlrA is involved in regulating the Wag31 polar foci.
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Affiliation(s)
- Samantha Y. Quintanilla
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
| | - Neda Habibi Arejan
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
| | - Parthvi B. Patel
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
| | - Cara C. Boutte
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
- * E-mail:
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9
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Feng S, Liang L, Shen C, Lin D, Li J, Lyu L, Liang W, Zhong LL, Cook GM, Doi Y, Chen C, Tian GB. A CRISPR-guided mutagenic DNA polymerase strategy for the detection of antibiotic-resistant mutations in M. tuberculosis. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 29:354-367. [PMID: 35950213 PMCID: PMC9358013 DOI: 10.1016/j.omtn.2022.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 07/08/2022] [Indexed: 11/26/2022]
Abstract
A sharp increase in multidrug-resistant tuberculosis (MDR-TB) threatens human health. Spontaneous mutation in essential gene confers an ability of Mycobacterium tuberculosis resistance to anti-TB drugs. However, conventional laboratory strategies for identification and prediction of the mutations in this slowly growing species remain challenging. Here, by combining XCas9 nickase and the error-prone DNA polymerase A from M. tuberculosis, we constructed a CRISPR-guided DNA polymerase system, CAMPER, for effective site-directed mutagenesis of drug-target genes in mycobacteria. CAMPER was able to generate mutagenesis of all nucleotides at user-defined loci, and its bidirectional mutagenesis at nick sites allowed editing windows with lengths up to 80 nucleotides. Mutagenesis of drug-targeted genes in Mycobacterium smegmatis and M. tuberculosis with this system significantly increased the fraction of the antibiotic-resistant bacterial population to a level approximately 60- to 120-fold higher than that in unedited cells. Moreover, this strategy could facilitate the discovery of the mutation conferring antibiotic resistance and enable a rapid verification of the growth phenotype-mutation genotype association. Our data demonstrate that CAMPER facilitates targeted mutagenesis of genomic loci and thus may be useful for broad functions such as resistance prediction and development of novel TB therapies.
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10
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Shamma F, Rego EH, Boutte CC. Mycobacterial serine/threonine phosphatase PstP is phosphoregulated and localized to mediate control of cell wall metabolism. Mol Microbiol 2022; 118:47-60. [PMID: 35670057 PMCID: PMC10070032 DOI: 10.1111/mmi.14951] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 05/12/2022] [Accepted: 06/01/2022] [Indexed: 11/26/2022]
Abstract
The mycobacterial cell wall is profoundly regulated in response to environmental stresses, and this regulation contributes to antibiotic tolerance. The reversible phosphorylation of different cell wall regulatory proteins is a major mechanism of cell wall regulation. Eleven serine/threonine protein kinases phosphorylate many critical cell wall-related proteins in mycobacteria. PstP is the sole serine/ threonine phosphatase, but few proteins have been verified as PstP substrates. PstP is itself phosphorylated, but the role of its phosphorylation in regulating its activity has been unclear. In this study, we aim to discover novel substrates of PstP in Mycobacterium tuberculosis (Mtb). We show in vitro that PstP dephosphorylates two regulators of peptidoglycan in Mtb, FhaA, and Wag31. We also show that a phosphomimetic mutation of T137 on PstP negatively regulates its catalytic activity against the cell wall regulators FhaA, Wag31, CwlM, PknB, and PknA, and that the corresponding mutation in Mycobacterium smegmatis causes misregulation of peptidoglycan in vivo. We show that PstP is localized to the septum, which likely restricts its access to certain substrates. These findings on the regulation of PstP provide insight into the control of cell wall metabolism in mycobacteria.
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Affiliation(s)
- Farah Shamma
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - E Hesper Rego
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Cara C Boutte
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
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11
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Liu K, Lin GH, Liu K, Liu YJ, Tao XY, Gao B, Zhao M, Wei DZ, Wang FQ. Multiplexed site-specific genome engineering in Mycolicibacterium neoaurum by Att/Int system. Synth Syst Biotechnol 2022; 7:1002-1011. [PMID: 35782483 PMCID: PMC9213222 DOI: 10.1016/j.synbio.2022.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 05/04/2022] [Accepted: 05/25/2022] [Indexed: 11/10/2022] Open
Abstract
Genomic integration of genes and pathway-sized DNA cassettes is often an indispensable way to construct robust and productive microbial cell factories. For some uncommon microbial hosts, such as Mycolicibacterium and Mycobacterium species, however, it is a challenge. Here, we present a multiplexed integrase-assisted site-specific recombination (miSSR) method to precisely and iteratively integrate genes/pathways with controllable copies in the chromosomes of Mycolicibacteria for the purpose of developing cell factories. First, a single-step multi-copy integration method was established in M. neoaurum by a combination application of mycobacteriophage L5 integrase and two-step allelic exchange strategy, the efficiencies of which were ∼100% for no more than three-copy integration events and decreased sharply to ∼20% for five-copy integration events. Second, the R4, Bxb1 and ΦC31 bacteriophage Att/Int systems were selected to extend the available integration toolbox for multiplexed gene integration events. Third, a reconstructed mycolicibacterial Xer recombinases (Xer-cise) system was employed to recycle the selection marker of gene recombination to facilitate the iterative gene manipulation. As a proof of concept, the biosynthetic pathway of ergothioneine (EGT) in Mycolicibacterium neoaurum ATCC 25795 was achieved by remodeling its metabolic pathway with a miSSR system. With six copies of the biosynthetic gene clusters (BGCs) of EGT and pentose phosphate isomerase (PRT), the titer of EGT in the resulting strain in a 30 mL shake flask within 5 days was enhanced to 66 mg/L, which was 3.77 times of that in the wild strain. The improvements indicated that the miSSR system was an effective, flexible, and convenient tool to engineer the genomes of Mycolicibacteria as well as other strains in the Mycobacteriaceae due to their proximate evolutionary relationships.
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12
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Prusa J, Zhu DX, Flynn AJ, Jensen D, Ruiz Manzano A, Galburt EA, Stallings CL. Molecular dissection of RbpA-mediated regulation of fidaxomicin sensitivity in mycobacteria. J Biol Chem 2022; 298:101752. [PMID: 35189142 PMCID: PMC8956947 DOI: 10.1016/j.jbc.2022.101752] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 01/13/2023] Open
Abstract
RNA polymerase (RNAP) binding protein A (RbpA) is essential for mycobacterial viability and regulates transcription initiation by increasing the stability of the RNAP-promoter open complex (RPo). RbpA consists of four domains: an N-terminal tail (NTT), a core domain (CD), a basic linker, and a sigma interaction domain. We have previously shown that truncation of the RbpA NTT and CD increases RPo stabilization by RbpA, implying that these domains inhibit this activity of RbpA. Previously published structural studies showed that the NTT and CD are positioned near multiple RNAP-σA holoenzyme functional domains and predict that the RbpA NTT contributes specific amino acids to the binding site of the antibiotic fidaxomicin (Fdx), which inhibits the formation of the RPo complex. Furthermore, deletion of the NTT results in decreased Mycobacterium smegmatis sensitivity to Fdx, but whether this is caused by a loss in Fdx binding is unknown. We generated a panel of rbpA mutants and found that the RbpA NTT residues predicted to directly interact with Fdx are partially responsible for RbpA-dependent Fdx activity in vitro, while multiple additional RbpA domains contribute to Fdx activity in vivo. Specifically, our results suggest that the RPo-stabilizing activity of RbpA decreases Fdx activity in vivo. In support of the association between RPo stability and Fdx activity, we find that another factor that promotes RPo stability in bacteria, CarD, also impacts to Fdx sensitivity. Our findings highlight how RbpA and other factors may influence RNAP dynamics to affect Fdx sensitivity.
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Affiliation(s)
- Jerome Prusa
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Dennis X. Zhu
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Aidan J. Flynn
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Drake Jensen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ana Ruiz Manzano
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eric A. Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christina L. Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA,For correspondence: Christina L. Stallings
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13
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Gupta KR, Gwin CM, Rahlwes KC, Biegas KJ, Wang C, Park JH, Liu J, Swarts BM, Morita YS, Rego EH. An essential periplasmic protein coordinates lipid trafficking and is required for asymmetric polar growth in mycobacteria. eLife 2022; 11:80395. [PMID: 36346214 PMCID: PMC9678360 DOI: 10.7554/elife.80395] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 11/07/2022] [Indexed: 11/10/2022] Open
Abstract
Mycobacteria, including the human pathogen Mycobacterium tuberculosis, grow by inserting new cell wall material at their poles. This process and that of division are asymmetric, producing a phenotypically heterogeneous population of cells that respond non-uniformly to stress (Aldridge et al., 2012; Rego et al., 2017). Surprisingly, deletion of a single gene - lamA - leads to more symmetry, and to a population of cells that is more uniformly killed by antibiotics (Rego et al., 2017). How does LamA create asymmetry? Here, using a combination of quantitative time-lapse imaging, bacterial genetics, and lipid profiling, we find that LamA recruits essential proteins involved in cell wall synthesis to one side of the cell - the old pole. One of these proteins, MSMEG_0317, here renamed PgfA, was of unknown function. We show that PgfA is a periplasmic protein that interacts with MmpL3, an essential transporter that flips mycolic acids in the form of trehalose monomycolate (TMM), across the plasma membrane. PgfA interacts with a TMM analog suggesting a direct role in TMM transport. Yet our data point to a broader function as well, as cells with altered PgfA levels have differences in the abundance of other lipids and are differentially reliant on those lipids for survival. Overexpression of PgfA, but not MmpL3, restores growth at the old poles in cells missing lamA. Together, our results suggest that PgfA is a key determinant of polar growth and cell envelope composition in mycobacteria, and that the LamA-mediated recruitment of this protein to one side of the cell is a required step in the establishment of cellular asymmetry.
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Affiliation(s)
- Kuldeepkumar R Gupta
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Celena M Gwin
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Kathryn C Rahlwes
- Department of Microbiology, University of MassachusettsAmherstUnited States
| | - Kyle J Biegas
- Department of Chemistry and Biochemistry, Central Michigan UniversityMount PleasantUnited States,Biochemistry, Cell, and Molecular Biology Program, Central Michigan UniversityMount PleasantUnited States
| | - Chunyan Wang
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States,Microbial Sciences Institute, Yale UniversityWest HavenUnited States
| | - Jin Ho Park
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States,Microbial Sciences Institute, Yale UniversityWest HavenUnited States
| | - Benjamin M Swarts
- Department of Chemistry and Biochemistry, Central Michigan UniversityMount PleasantUnited States,Biochemistry, Cell, and Molecular Biology Program, Central Michigan UniversityMount PleasantUnited States
| | - Yasu S Morita
- Department of Microbiology, University of MassachusettsAmherstUnited States
| | - E Hesper Rego
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
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14
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Liu K, Gao Y, Li ZH, Liu M, Wang FQ, Wei DZ. CRISPR-Cas12a assisted precise genome editing of Mycolicibacterium neoaurum. N Biotechnol 2021; 66:61-69. [PMID: 34653700 DOI: 10.1016/j.nbt.2021.10.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/09/2021] [Accepted: 10/10/2021] [Indexed: 12/27/2022]
Abstract
Efficient and convenient genetic manipulation of mycobacteria, important microorganisms in human healthcare and the pharmaceutical industry, is limited. In this study, using a model strain Mycolicibacterium neoaurum ATCC 25795, the classical bacterium for the production of valuable steroidal pharmaceuticals, a genome editing system employing CRISPR-Cas12a to achieve efficient and precise genetic manipulation has been developed. Targeted genome mutations could be easily achieved by the CRISPR-Cas12a system without exogenous donor templates, assisted by innate non-homologous end-joining (NHEJ). CRISPR-Cas12a enabled rapid one-step genomic DNA fragment deletions of 1 kb, 5 kb, 10 kb, 15 kb, 20 kb and 24 kb with efficiencies of 70 %, 30 %, 30 %, 20 %, 20 % and 10 %, respectively. Combined with the pNIL/pGOAL system, CRISPR-Cas12a successfully integrated the gene of interest into the targeted genomic site by single crossover and double crossovers with efficiencies of 100 % and 9 %, respectively, using a two-plasmid system. The robust CRISPR systems developed demonstrated strong potential for precise genome editing in M. neoaurum, including targeted deletion of DNA sequences of various lengths and integration of targeted genes into desired sites in the genome.
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Affiliation(s)
- Ke Liu
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Yang Gao
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Zhen-Hai Li
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Min Liu
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Feng-Qing Wang
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
| | - Dong-Zhi Wei
- State Key Laboratory of Bioreactor Engineering, Newworld Institute of Biotechnology, East China University of Science and Technology, Shanghai, 200237, China.
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15
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Abstract
Current models of horizontal gene transfer (HGT) in mycobacteria are based on “distributive conjugal transfer” (DCT), an HGT type described in the fast-growing, saprophytic model organism Mycobacterium smegmatis, which creates genome mosaicism in resulting strains and depends on an ESX-1 type VII secretion system. In contrast, only few data on interstrain DNA transfer are available for tuberculosis-causing mycobacteria, for which chromosomal DNA transfer between two Mycobacterium canettii strains was reported, a process which, however, was not observed for Mycobacterium tuberculosis strains. Here, we have studied a wide range of human- and animal-adapted members of the Mycobacterium tuberculosis complex (MTBC) using an optimized filter-based mating assay together with three selected strains of M. canettii that acted as DNA recipients. Unlike in previous approaches, we obtained a high yield of thousands of recombinants containing transferred chromosomal DNA fragments from various MTBC donor strains, as confirmed by whole-genome sequence analysis of 38 randomly selected clones. While the genome organizations of the obtained recombinants showed mosaicisms of donor DNA fragments randomly integrated into a recipient genome backbone, reminiscent of those described as being the result of ESX-1-mediated DCT in M. smegmatis, we observed similar transfer efficiencies when ESX-1-deficient donor and/or recipient mutants were used, arguing that in tubercle bacilli, HGT is an ESX-1-independent process. These findings provide new insights into the genetic events driving the pathoevolution of M. tuberculosis and radically change our perception of HGT in mycobacteria, particularly for those species that show recombinogenic population structures despite the natural absence of ESX-1 secretion systems.
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16
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Campo-Pérez V, Cendra MDM, Julián E, Torrents E. Easily applicable modifications to electroporation conditions improve the transformation efficiency rates for rough morphotypes of fast-growing mycobacteria. N Biotechnol 2021; 63:10-18. [PMID: 33636348 DOI: 10.1016/j.nbt.2021.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 02/17/2021] [Accepted: 02/20/2021] [Indexed: 10/22/2022]
Abstract
Electroporation is the most widely used and efficient method to transform mycobacteria. Through this technique, fast- and slow-growing mycobacteria with smooth and rough morphotypes have been successfully transformed. However, transformation efficiencies differ widely between species and strains. In this study, the smooth and rough morphotypes of Mycobacteroides abscessus and Mycolicibacterium brumae were used to improve current electroporation procedures for fast-growing rough mycobacteria. The focus was on minimizing three well-known and challenging limitations: the mycobacterial restriction-modification systems, which degrade foreign DNA; clump formation of electrocompetent cells before electroporation; and electrical discharges during pulse delivery, which were reduced by using salt-free DNA solution. Herein, different strategies are presented that successfully address these three limitations and clearly improve the electroporation efficiencies over the current procedures. The results demonstrated that combining the developed strategies during electroporation is highly recommended for the transformation of fast-growing rough mycobacteria.
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Affiliation(s)
- Víctor Campo-Pérez
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 15-21, Barcelona, 08028, Spain; Department of Genetics and Microbiology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain
| | - Maria Del Mar Cendra
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 15-21, Barcelona, 08028, Spain
| | - Esther Julián
- Department of Genetics and Microbiology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Barcelona, 08193, Spain.
| | - Eduard Torrents
- Bacterial Infections and Antimicrobial Therapies Group, Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology (BIST), Baldiri Reixac 15-21, Barcelona, 08028, Spain; Microbiology Section, Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, 643 Diagonal Ave., Barcelona, 08028, Spain.
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17
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Phosphorylation on PstP Regulates Cell Wall Metabolism and Antibiotic Tolerance in Mycobacterium smegmatis. J Bacteriol 2021; 203:JB.00563-20. [PMID: 33257524 DOI: 10.1128/jb.00563-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/18/2020] [Indexed: 12/18/2022] Open
Abstract
Mycobacterium tuberculosis and its relatives, like many bacteria, have dynamic cell walls that respond to environmental stresses. Modulation of cell wall metabolism in stress is thought to be responsible for decreased permeability and increased tolerance to antibiotics. The signaling systems that control cell wall metabolism under stress, however, are poorly understood. Here, we examine the cell wall regulatory function of a key cell wall regulator, the serine/threonine phosphatase PstP, in the model organism Mycobacterium smegmatis We show that the peptidoglycan regulator CwlM is a substrate of PstP. We find that a phosphomimetic mutation, pstP T171E, slows growth, misregulates both mycolic acid and peptidoglycan metabolism in different conditions, and interferes with antibiotic tolerance. These data suggest that phosphorylation on PstP affects its activity against various substrates and is important in the transition between growth and stasis.IMPORTANCE Regulation of cell wall assembly is essential for bacterial survival and contributes to pathogenesis and antibiotic tolerance in mycobacteria, including pathogens such as Mycobacterium tuberculosis However, little is known about how the cell wall is regulated in stress. We describe a pathway of cell wall modulation in Mycobacterium smegmatis through the only essential Ser/Thr phosphatase, PstP. We showed that phosphorylation on PstP is important in regulating peptidoglycan metabolism in the transition to stasis and mycolic acid metabolism in growth. This regulation also affects antibiotic tolerance in growth and stasis. This work helps us to better understand the phosphorylation-mediated cell wall regulation circuitry in Mycobacteria.
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18
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Brown AC. Gene Switching and Essentiality Testing. Methods Mol Biol 2021; 2314:285-299. [PMID: 34235659 DOI: 10.1007/978-1-0716-1460-0_13] [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: 12/14/2022]
Abstract
The identification of essential genes is of major importance to mycobacterial research, and a number of essential genes have been identified in mycobacteria, however confirming essentiality is not straightforward, as deletion of essential genes results in a lethal phenotype. In this chapter, protocols are described which can be used to confirm gene essentiality using gene switching, following the construction of a strain carrying its only functional copy on an integrated plasmid (Δ'int). Since deletion mutants cannot be created for essential genes, a second gene copy is introduced via an integrating vector, which allows the chromosomal gene copy to be deleted. The integrated vector can then be replaced using the gene switching method, where no transformants are obtained, essentiality is confirmed. This technique can also be used to confirm functionality of gene homologs and to easily identify essential operon members.
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Affiliation(s)
- Amanda Claire Brown
- Texas A&M Veterinary Medical Diagnostic Laboratory (TVDML), College Station, TX, USA.
- Department of Animal Science, Texas A&M University, Kleberg Center, College Station, TX, USA.
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19
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Hicks ND, Giffen SR, Culviner PH, Chao MC, Dulberger CL, Liu Q, Stanley S, Brown J, Sixsmith J, Wolf ID, Fortune SM. Mutations in dnaA and a cryptic interaction site increase drug resistance in Mycobacterium tuberculosis. PLoS Pathog 2020; 16:e1009063. [PMID: 33253310 PMCID: PMC7738170 DOI: 10.1371/journal.ppat.1009063] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/15/2020] [Accepted: 10/09/2020] [Indexed: 01/26/2023] Open
Abstract
Genomic dissection of antibiotic resistance in bacterial pathogens has largely focused on genetic changes conferring growth above a single critical concentration of drug. However, reduced susceptibility to antibiotics-even below this breakpoint-is associated with poor treatment outcomes in the clinic, including in tuberculosis. Clinical strains of Mycobacterium tuberculosis exhibit extensive quantitative variation in antibiotic susceptibility but the genetic basis behind this spectrum of drug susceptibility remains ill-defined. Through a genome wide association study, we show that non-synonymous mutations in dnaA, which encodes an essential and highly conserved regulator of DNA replication, are associated with drug resistance in clinical M. tuberculosis strains. We demonstrate that these dnaA mutations specifically enhance M. tuberculosis survival during isoniazid treatment via reduced expression of katG, the activator of isoniazid. To identify DnaA interactors relevant to this phenotype, we perform the first genome-wide biochemical mapping of DnaA binding sites in mycobacteria which reveals a DnaA interaction site that is the target of recurrent mutation in clinical strains. Reconstructing clinically prevalent mutations in this DnaA interaction site reproduces the phenotypes of dnaA mutants, suggesting that clinical strains of M. tuberculosis have evolved mutations in a previously uncharacterized DnaA pathway that quantitatively increases resistance to the key first-line antibiotic isoniazid. Discovering genetic mechanisms that reduce drug susceptibility and support the evolution of high-level drug resistance will guide development of biomarkers capable of prospectively identifying patients at risk of treatment failure in the clinic.
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Affiliation(s)
- Nathan D. Hicks
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Samantha R. Giffen
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Peter H. Culviner
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Michael C. Chao
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Charles L. Dulberger
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Qingyun Liu
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Sydney Stanley
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Jessica Brown
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Jaimie Sixsmith
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Ian D. Wolf
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Sarah M. Fortune
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Ragon Institute of MGH, MIT, and Harvard, Cambridge, Massachusetts, United States of America
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
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20
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Zaveri A, Wang R, Botella L, Sharma R, Zhu L, Wallach JB, Song N, Jansen RS, Rhee KY, Ehrt S, Schnappinger D. Depletion of the DarG antitoxin in Mycobacterium tuberculosis triggers the DNA-damage response and leads to cell death. Mol Microbiol 2020; 114:641-652. [PMID: 32634279 PMCID: PMC7689832 DOI: 10.1111/mmi.14571] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/28/2020] [Accepted: 07/01/2020] [Indexed: 01/01/2023]
Abstract
Of the ~80 putative toxin-antitoxin (TA) modules encoded by the bacterial pathogen Mycobacterium tuberculosis (Mtb), three contain antitoxins essential for bacterial viability. One of these, Rv0060 (DNA ADP-ribosyl glycohydrolase, DarGMtb ), functions along with its cognate toxin Rv0059 (DNA ADP-ribosyl transferase, DarTMtb ), to mediate reversible DNA ADP-ribosylation (Jankevicius et al., 2016). We demonstrate that DarTMtb -DarGMtb form a functional TA pair and essentiality of darGMtb is dependent on the presence of darTMtb , but simultaneous deletion of both darTMtb -darGMtb does not alter viability of Mtb in vitro or in mice. The antitoxin, DarGMtb , forms a cytosolic complex with DNA-repair proteins that assembles independently of either DarTMtb or interaction with DNA. Depletion of DarGMtb alone is bactericidal, a phenotype that is rescued by expression of an orthologous antitoxin, DarGTaq , from Thermus aquaticus. Partial depletion of DarGMtb triggers a DNA-damage response and sensitizes Mtb to drugs targeting DNA metabolism and respiration. Induction of the DNA-damage response is essential for Mtb to survive partial DarGMtb -depletion and leads to a hypermutable phenotype.
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Affiliation(s)
- Anisha Zaveri
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ruojun Wang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Ritu Sharma
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Linnan Zhu
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Joshua B Wallach
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Naomi Song
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Robert S Jansen
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Kyu Y Rhee
- Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
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21
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Mycobacterium smegmatis HtrA Blocks the Toxic Activity of a Putative Cell Wall Amidase. Cell Rep 2020; 27:2468-2479.e3. [PMID: 31116989 PMCID: PMC6538288 DOI: 10.1016/j.celrep.2018.12.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/14/2018] [Accepted: 12/13/2018] [Indexed: 01/14/2023] Open
Abstract
Mycobacterium tuberculosis, the causative agent of tuberculosis, withstands diverse environmental stresses in the host. The periplasmic protease HtrA is required only to survive extreme conditions in most bacteria but is predicted to be essential for normal growth in mycobacteria. We confirm that HtrA is indeed essential in Mycobacterium smegmatis and interacts with another essential protein of unknown function, LppZ. However, the loss of any of three unlinked genes, including those encoding Ami3, a peptidoglycan muramidase, and Pmt, a mannosyltransferase, suppresses the essentiality of both HtrA and LppZ, indicating the functional relevance of these genes' protein products. Our data indicate that HtrA-LppZ is required to counteract the accumulation of active Ami3, which is toxic under the stabilizing influence of Pmt-based mannosylation. This suggests that HtrA-LppZ blocks the toxicity of a cell wall enzyme to maintain mycobacterial homeostasis.
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22
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Plasticity of the Mycobacterium tuberculosis respiratory chain and its impact on tuberculosis drug development. Nat Commun 2019; 10:4970. [PMID: 31672993 PMCID: PMC6823465 DOI: 10.1038/s41467-019-12956-2] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 10/09/2019] [Indexed: 12/30/2022] Open
Abstract
The viability of Mycobacterium tuberculosis (Mtb) depends on energy generated by its respiratory chain. Cytochrome bc1-aa3 oxidase and type-2 NADH dehydrogenase (NDH-2) are respiratory chain components predicted to be essential, and are currently targeted for drug development. Here we demonstrate that an Mtb cytochrome bc1-aa3 oxidase deletion mutant is viable and only partially attenuated in mice. Moreover, treatment of Mtb-infected marmosets with a cytochrome bc1-aa3 oxidase inhibitor controls disease progression and reduces lesion-associated inflammation, but most lesions become cavitary. Deletion of both NDH-2 encoding genes (Δndh-2 mutant) reveals that the essentiality of NDH-2 as shown in standard growth media is due to the presence of fatty acids. The Δndh-2 mutant is only mildly attenuated in mice and not differently susceptible to clofazimine, a drug in clinical use proposed to engage NDH-2. These results demonstrate the intrinsic plasticity of Mtb's respiratory chain, and highlight the challenges associated with targeting the pathogen's respiratory enzymes for tuberculosis drug development.
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Vanunu M, Schall P, Reingewertz TH, Chakraborti PK, Grimm B, Barkan D. MapB Protein is the Essential Methionine Aminopeptidase in Mycobacterium tuberculosis. Cells 2019; 8:cells8050393. [PMID: 31035386 PMCID: PMC6562599 DOI: 10.3390/cells8050393] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 12/16/2022] Open
Abstract
M. tuberculosis (Mtb), which causes tuberculosis disease, continues to be a major global health threat. Correct identification of valid drug targets is important for the development of novel therapeutics that would shorten the current 6-9 month treatment regimen and target resistant bacteria. Methionine aminopeptidases (MetAP), which remove the N-terminal methionine from newly synthesized proteins, are essential in all life forms (eukaryotes and prokaryotes). The MetAPs contribute to the cotranslational control of proteins as they determine their half life (N-terminal end rule) and facilitate further modifications such as acetylation and others. Mtb (and M. bovis) possess two MetAP isoforms, MetAP1a and MetAP1c, encoded by the mapA and mapB genes, respectively. Conflicting evidence was reported in the literature on which of the two variants is essential. To resolve this question, we performed a targeted genetic deletion of each of these two genes. We show that a deletion mutant of mapA is viable with only a weak growth defect. In contrast, we provide two lines of genetic evidence that mapB is indispensable. Furthermore, construction of double-deletion mutants as well as the introduction of point mutations into mapB resulting in proteins with partial activity showed partial, but not full, redundancy between mapB and mapA. We propose that it is MetAP1c (mapB) that is essentially required for mycobacteria and discuss potential reasons for its vitality.
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Affiliation(s)
- Miriam Vanunu
- Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Nutrition and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Patrick Schall
- Humboldt-Universität zu Berlin, Institute of Biology/Plant Physiology, Philippstr.13, Building 12, 10115 Berlin, Germany.
| | - Tali-Haviv Reingewertz
- Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Nutrition and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
| | - Pradip K Chakraborti
- Department of Biotechnology, School of Chemical and Life Sciences, Jamia Hamdard, Hamdar Nagar, New Delhi 110062, India.
| | - Bernhard Grimm
- Humboldt-Universität zu Berlin, Institute of Biology/Plant Physiology, Philippstr.13, Building 12, 10115 Berlin, Germany.
| | - Daniel Barkan
- Koret School of Veterinary Medicine, Robert H. Smith Faculty of Agriculture, Nutrition and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
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Dhiman RK, Pujari V, Kincaid JM, Ikeh MA, Parish T, Crick DC. Characterization of MenA (isoprenyl diphosphate:1,4-dihydroxy-2-naphthoate isoprenyltransferase) from Mycobacterium tuberculosis. PLoS One 2019; 14:e0214958. [PMID: 30978223 PMCID: PMC6461227 DOI: 10.1371/journal.pone.0214958] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/22/2019] [Indexed: 12/18/2022] Open
Abstract
The menaquinone biosynthetic pathway presents a promising drug target against Mycobacterium tuberculosis and potentially other Gram-positive pathogens. In the present study, the essentiality, steady state kinetics of MenA from M. tuberculosis and the mechanism of MenA inhibition by Ro 48-8071 were characterized. MenA [isoprenyl diphosphate:1,4-dihydroxy-2-naphthoate (DHNA) isoprenyltransferase] catalyzes a critical reaction in menaquinone biosynthesis that involves the conversion of cytosolic DHNA, to membrane bound demethylmenaquinone by transferring a hydrophobic 45-carbon isoprenoid chain (in the case of mycobacteria) to the ring nucleus of DHNA. Rv0534c previously identified as the gene encoding MenA in M. tuberculosis complemented a menA deletion in E. coli and an E. coli host expressing Rv0534c exhibited an eight-fold increase in MenA specific activity over the control strain harboring empty vector under similar assay conditions. Expression of Rv0534c is essential for mycobacterial survival and the native enzyme from M. tuberculosis H37Rv was characterized using membrane preparations as it was not possible to solubilize and purify the recombinant enzyme. The enzyme is absolutely dependent on the presence of a divalent cation for optimal activity with Mg+2 being the most effective and is active over a wide pH range, with pH 8.5 being optimal. The apparent Km values for DHNA and farnesyl diphosphate were found to be 8.2 and 4.3 μM, respectively. Ro 48-8071, a compound previously reported to inhibit mycobacterial MenA activity, is non-competitive with regard to DHNA and competitive with regard to the isoprenyldiphosphate substrate.
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Affiliation(s)
- Rakesh K. Dhiman
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Venugopal Pujari
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - James M. Kincaid
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Melanie A. Ikeh
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, London, United Kingdom
| | - Tanya Parish
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, London, United Kingdom
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, United States of America
| | - Dean C. Crick
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
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Kilpeläinen A, Maya-Hoyos M, Saubí N, Soto CY, Joseph Munne J. Advances and challenges in recombinant Mycobacterium bovis BCG-based HIV vaccine development: lessons learned. Expert Rev Vaccines 2018; 17:1005-1020. [PMID: 30300040 DOI: 10.1080/14760584.2018.1534588] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome, tuberculosis, and malaria are responsible for most human deaths produced by infectious diseases worldwide. Vaccination against HIV requires generation of memory T cells and neutralizing antibodies, mucosal immunity, and stimulation of an innate immune responses. In this context, the use of Mycobacterium bovis bacillus Calmette-Guérin (BCG) as a live vaccine vehicle is a promising approach for T-cell induction. AREAS COVERED In this review, we provide a comprehensive summary of the literature regarding immunogenicity studies in animal models performed since 2005. Furthermore, we provide expert commentary and 5-year view on how the development of potential recombinant BCG-based HIV vaccines involves careful selection of the HIV antigen, expression vectors, promoters, BCG strain, preclinical animal models, influence of preexisting immunity, and safety issues, for the rational design of recombinant BCG:HIV vaccines to prevent HIV transmission in the general population. EXPERT COMMENTARY The three critical issues to be considered when developing a rBCG:HIV vaccine are codon optimization, antigen localization, and plasmid stability in vivo. The use of integrative expression vectors are likely to improve the mycobacterial vaccine stability and immunogenicity to develop not only recombinant BCG-based vaccines expressing second generation of HIV-1 immunogens but also other major pediatric pathogens to prime protective responses shortly following birth.
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Affiliation(s)
- Athina Kilpeläinen
- a Catalan Center for HIV Vaccine Research and Development, AIDS Research Unit, Infectious Diseases Department, Hospital Clínic/IDIBAPS, School of Medicine , University of Barcelona , Barcelona , Spain
| | - Milena Maya-Hoyos
- b Chemistry Department, Faculty of Sciences , Universidad Nacional de Colombia, Ciudad Universitaria , Bogotá , Colombia
| | - Narcís Saubí
- a Catalan Center for HIV Vaccine Research and Development, AIDS Research Unit, Infectious Diseases Department, Hospital Clínic/IDIBAPS, School of Medicine , University of Barcelona , Barcelona , Spain
| | - Carlos Y Soto
- b Chemistry Department, Faculty of Sciences , Universidad Nacional de Colombia, Ciudad Universitaria , Bogotá , Colombia
| | - Joan Joseph Munne
- a Catalan Center for HIV Vaccine Research and Development, AIDS Research Unit, Infectious Diseases Department, Hospital Clínic/IDIBAPS, School of Medicine , University of Barcelona , Barcelona , Spain
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Prusa J, Jensen D, Santiago-Collazo G, Pope SS, Garner AL, Miller JJ, Ruiz Manzano A, Galburt EA, Stallings CL. Domains within RbpA Serve Specific Functional Roles That Regulate the Expression of Distinct Mycobacterial Gene Subsets. J Bacteriol 2018; 200:e00690-17. [PMID: 29686140 PMCID: PMC5996690 DOI: 10.1128/jb.00690-17] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 04/18/2018] [Indexed: 11/20/2022] Open
Abstract
The RNA polymerase (RNAP) binding protein A (RbpA) contributes to the formation of stable RNAP-promoter open complexes (RPo) and is essential for viability in mycobacteria. Four domains have been identified in the RbpA protein, i.e., an N-terminal tail (NTT) that interacts with RNAP β' and σ subunits, a core domain (CD) that contacts the RNAP β' subunit, a basic linker (BL) that binds DNA, and a σ-interaction domain (SID) that binds group I and group II σ factors. Limited in vivo studies have been performed in mycobacteria, however, and how individual structural domains of RbpA contribute to RbpA function and mycobacterial gene expression remains mostly unknown. We investigated the roles of the RbpA structural domains in mycobacteria using a panel of rbpA mutants that target individual RbpA domains. The function of each RbpA domain was required for Mycobacterium tuberculosis viability and optimal growth in Mycobacterium smegmatis We determined that the RbpA SID is both necessary and sufficient for RbpA interaction with the RNAP, indicating that the primary functions of the NTT and CD are not solely association with the RNAP. We show that the RbpA BL and SID are required for RPo stabilization in vitro, while the NTT and CD antagonize this activity. Finally, RNA-sequencing analyses suggest that the NTT and CD broadly activate gene expression, whereas the BL and SID activate or repress gene expression in a gene-dependent manner for a subset of mycobacterial genes. Our findings highlight specific outcomes for the activities of the individual functional domains in RbpA.IMPORTANCEMycobacterium tuberculosis is the causative agent of tuberculosis and continues to be the most lethal infectious disease worldwide. Improved molecular understanding of the essential proteins involved in M. tuberculosis transcription, such as RbpA, could provide targets for much needed future therapeutic agents aimed at combatting this pathogen. In this study, we expand our understanding of RbpA by identifying the RbpA structural domains responsible for the interaction of RbpA with the RNAP and the effects of RbpA on transcription initiation and gene expression. These experiments expand our knowledge of RbpA while also broadening our understanding of bacterial transcription in general.
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Affiliation(s)
- Jerome Prusa
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Drake Jensen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gustavo Santiago-Collazo
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Steven S Pope
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ashley L Garner
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Justin J Miller
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ana Ruiz Manzano
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Eric A Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Christina L Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
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Chhotaray C, Tan Y, Mugweru J, Islam MM, Adnan Hameed HM, Wang S, Lu Z, Wang C, Li X, Tan S, Liu J, Zhang T. Advances in the development of molecular genetic tools for Mycobacterium tuberculosis. J Genet Genomics 2018; 45:S1673-8527(18)30114-0. [PMID: 29941353 DOI: 10.1016/j.jgg.2018.06.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mycobacterium tuberculosis, a clinically relevant Gram-positive bacterium of great clinical relevance, is a lethal pathogen owing to its complex physiological characteristics and development of drug resistance. Several molecular genetic tools have been developed in the past few decades to study this microorganism. These tools have been instrumental in understanding how M. tuberculosis became a successful pathogen. Advanced molecular genetic tools have played a significant role in exploring the complex pathways involved in M. tuberculosis pathogenesis. Here, we review various molecular genetic tools used in the study of M. tuberculosis. Further, we discuss the applications of clustered regularly interspaced short palindromic repeat interference (CRISPRi), a novel technology recently applied in M. tuberculosis research to study target gene functions. Finally, prospective outcomes of the applications of molecular techniques in the field of M. tuberculosis genetic research are also discussed.
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Affiliation(s)
- Chiranjibi Chhotaray
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaoju Tan
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou 510095, China
| | - Julius Mugweru
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; University of Chinese Academy of Sciences, Beijing 100049, China; Department of Biological Sciences, University of Embu, P.O Box 6 -60100, Embu, Kenya
| | - Md Mahmudul Islam
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - H M Adnan Hameed
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuai Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhili Lu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Changwei Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Xinjie Li
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou 510095, China
| | - Shouyong Tan
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou 510095, China
| | - Jianxiong Liu
- State Key Laboratory of Respiratory Disease, Department of Clinical Laboratory, Guangzhou Chest Hospital, Guangzhou 510095, China.
| | - Tianyu Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Characterization of Conserved and Novel Septal Factors in Mycobacterium smegmatis. J Bacteriol 2018; 200:JB.00649-17. [PMID: 29311277 DOI: 10.1128/jb.00649-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/14/2017] [Indexed: 11/20/2022] Open
Abstract
Septation in bacteria requires coordinated regulation of cell wall biosynthesis and hydrolysis enzymes so that new septal cross-wall can be appropriately constructed without compromising the integrity of the existing cell wall. Bacteria with different modes of growth and different types of cell wall require different regulators to mediate cell growth and division processes. Mycobacteria have both a cell wall structure and a mode of growth that are distinct from well-studied model organisms and use several different regulatory mechanisms. Here, using Mycobacterium smegmatis, we identify and characterize homologs of the conserved cell division regulators FtsL and FtsB, and show that they appear to function similarly to their homologs in Escherichia coli We identify a number of previously undescribed septally localized factors which could be involved in cell wall regulation. One of these, SepIVA, has a DivIVA domain, is required for mycobacterial septation, and is localized to the septum and the intracellular membrane domain. We propose that SepIVA is a regulator of cell wall precursor enzymes that contribute to construction of the septal cross-wall, similar to the putative elongation function of the other mycobacterial DivIVA homolog, Wag31.IMPORTANCE The enzymes that build bacterial cell walls are essential for cell survival but can cause cell lysis if misregulated; thus, their regulators are also essential. The number and nature of these regulators is likely to vary in bacteria that grow in different ways. The mycobacteria are a genus that have a cell wall whose composition and construction vary greatly from those of well-studied model organisms. In this work, we identify and characterize some of the proteins that regulate the mycobacterial cell wall. We find that some of these regulators appear to be functionally conserved with their structural homologs in evolutionarily distant species such as Escherichia coli, but other proteins have critical regulatory functions that may be unique to the actinomycetes.
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Boot M, van Winden VJC, Sparrius M, van de Weerd R, Speer A, Ummels R, Rustad T, Sherman DR, Bitter W. Cell envelope stress in mycobacteria is regulated by the novel signal transduction ATPase IniR in response to trehalose. PLoS Genet 2017; 13:e1007131. [PMID: 29281637 PMCID: PMC5760070 DOI: 10.1371/journal.pgen.1007131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 01/09/2018] [Accepted: 11/28/2017] [Indexed: 12/20/2022] Open
Abstract
The cell envelope of mycobacteria is a highly unique and complex structure that is functionally equivalent to that of Gram-negative bacteria to protect the bacterial cell. Defects in the integrity or assembly of this cell envelope must be sensed to allow the induction of stress response systems. The promoter that is specifically and most strongly induced upon exposure to ethambutol and isoniazid, first line drugs that affect cell envelope biogenesis, is the iniBAC promoter. In this study, we set out to identify the regulator of the iniBAC operon in Mycobacterium marinum using an unbiased transposon mutagenesis screen in a constitutively iniBAC-expressing mutant background. We obtained multiple mutants in the mce1 locus as well as mutants in an uncharacterized putative transcriptional regulator (MMAR_0612). This latter gene was shown to function as the iniBAC regulator, as overexpression resulted in constitutive iniBAC induction, whereas a knockout mutant was unable to respond to the presence of ethambutol and isoniazid. Experiments with the M. tuberculosis homologue (Rv0339c) showed identical results. RNAseq experiments showed that this regulatory gene was exclusively involved in the regulation of the iniBAC operon. We therefore propose to name this dedicated regulator iniBAC Regulator (IniR). IniR belongs to the family of signal transduction ATPases with numerous domains, including a putative sugar-binding domain. Upon testing different sugars, we identified trehalose as an activator and metabolic cue for iniBAC activation, which could also explain the effect of the mce1 mutations. In conclusion, cell envelope stress in mycobacteria is regulated by IniR in a cascade that includes trehalose.
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Affiliation(s)
- Maikel Boot
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Vincent J. C. van Winden
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Marion Sparrius
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Robert van de Weerd
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Alexander Speer
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Tige Rustad
- Center for Infectious Disease, Seattle, Washington, United States of America
| | - David R. Sherman
- Center for Infectious Disease, Seattle, Washington, United States of America
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
- Department of Molecular Microbiology, VU University, Amsterdam, the Netherlands
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The gene fmt, encoding tRNA fMet-formyl transferase, is essential for normal growth of M. bovis, but not for viability. Sci Rep 2017; 7:15161. [PMID: 29123253 PMCID: PMC5680289 DOI: 10.1038/s41598-017-15618-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 10/31/2017] [Indexed: 11/08/2022] Open
Abstract
Mycobacterium tuberculosis is a major health threat, necessitating novel drug targets. Protein synthesis in bacteria uses initiator tRNAi charged with formylated methionine residue. Deletion of the formylase gene, tRNAfMet-formyl transferase (fmt), causes severe growth-retardation in E. coli and in S. pneumoniae, but not in P. aeruginosa or S. aureus. fmt was predicted to be essential in M. tuberculosis by transposon library analysis, but this was never formally tested in any mycobacteria. We performed a targeted deletion of fmt in M. smegmatis as well as Mtb-complex (M. bovis). In both cases, we created a mero-diploid strain, deleted the native gene by two-step allelic exchange or specialized-phage transduction, and then removed the complementing gene to create full deletion mutants. In M. smegmatis a full deletion strain could be easily created. In contrast, in M. bovis-BCG, a full deletion strain could only be created after incubation of 6 weeks, with a generation time ~2 times longer than for wt bacteria. Our results confirm the importance of this gene in pathogenic mycobacteria, but as the deletion mutant is viable, validity of fmt as a drug target remains unclear. Our results also refute the previous reports that fmt is essential in M. tuberculosis-complex.
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31
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Boldrin F, Degiacomi G, Serafini A, Kolly GS, Ventura M, Sala C, Provvedi R, Palù G, Cole ST, Manganelli R. Promoter mutagenesis for fine-tuning expression of essential genes in Mycobacterium tuberculosis. Microb Biotechnol 2017; 11:238-247. [PMID: 29076636 PMCID: PMC5743821 DOI: 10.1111/1751-7915.12875] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 09/05/2017] [Accepted: 09/25/2017] [Indexed: 02/04/2023] Open
Abstract
A range of regulated gene expression systems has been developed for mycobacteria in the last few years to facilitate the study of essential genes, validate novel drug targets and evaluate their vulnerability. Among these, the TetR/Pip-OFF repressible promoter system was successfully used in several mycobacterial species both in vitro and in vivo. In the first version of the system, the repressible promoter was Pptr , a strong Pip-repressible promoter of Streptomyces pristinaespiralis, which might hamper effective downregulation of genes with a low basal expression level. Here, we report an enhanced system that allows more effective control of genes expressed at low level. To this end, we subjected Pptr to targeted mutagenesis and produced 16 different promoters with different strength. Three of them, weaker than the wild-type promoter, were selected and characterized showing that they can indeed improve the performances of TetR/Pip-OFF repressible system both in vitro and in vivo increasing its stringency. Finally, we used these promoters to construct a series of bacterial biosensors with different sensitivity to DprE1 inhibitors and developed a whole-cell screening assay to identify inhibitors of this enzyme.
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Affiliation(s)
- Francesca Boldrin
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Giulia Degiacomi
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Agnese Serafini
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Gaëlle S Kolly
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 19, 1015, Lausanne, Switzerland
| | - Marcello Ventura
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Claudia Sala
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 19, 1015, Lausanne, Switzerland
| | - Roberta Provvedi
- Department of Biology, University of Padova, 35121, Padova, Italy
| | - Giorgio Palù
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Stewart T Cole
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 19, 1015, Lausanne, Switzerland
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
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PknG senses amino acid availability to control metabolism and virulence of Mycobacterium tuberculosis. PLoS Pathog 2017; 13:e1006399. [PMID: 28545104 PMCID: PMC5448819 DOI: 10.1371/journal.ppat.1006399] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 05/30/2017] [Accepted: 05/04/2017] [Indexed: 11/19/2022] Open
Abstract
Sensing and response to changes in nutrient availability are essential for the lifestyle of environmental and pathogenic bacteria. Serine/threonine protein kinase G (PknG) is required for virulence of the human pathogen Mycobacterium tuberculosis, and its putative substrate GarA regulates the tricarboxylic acid cycle in M. tuberculosis and other Actinobacteria by protein-protein binding. We sought to understand the stimuli that lead to phosphorylation of GarA, and the roles of this regulatory system in pathogenic and non-pathogenic bacteria. We discovered that M. tuberculosis lacking garA was severely attenuated in mice and macrophages and furthermore that GarA lacking phosphorylation sites failed to restore the growth of garA deficient M. tuberculosis in macrophages. Additionally we examined the impact of genetic disruption of pknG or garA upon protein phosphorylation, nutrient utilization and the intracellular metabolome. We found that phosphorylation of GarA requires PknG and depends on nutrient availability, with glutamate and aspartate being the main stimuli. Disruption of pknG or garA caused opposing effects on metabolism: a defect in glutamate catabolism or depletion of intracellular glutamate, respectively. Strikingly, disruption of the phosphorylation sites of GarA was sufficient to recapitulate defects caused by pknG deletion. The results suggest that GarA is a cellular target of PknG and the metabolomics data demonstrate that the function of this signaling system is in metabolic regulation. This function in amino acid homeostasis is conserved amongst the Actinobacteria and provides an example of the close relationship between metabolism and virulence.
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Botella L, Vaubourgeix J, Livny J, Schnappinger D. Depleting Mycobacterium tuberculosis of the transcription termination factor Rho causes pervasive transcription and rapid death. Nat Commun 2017; 8:14731. [PMID: 28348398 PMCID: PMC5379054 DOI: 10.1038/ncomms14731] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/26/2017] [Indexed: 12/30/2022] Open
Abstract
Rifampicin, which inhibits bacterial RNA polymerase, provides one of the most effective treatments for tuberculosis. Inhibition of the transcription termination factor Rho is used to treat some bacterial infections, but its importance varies across bacteria. Here we show that Rho of Mycobacterium tuberculosis functions to both define the 3' ends of mRNAs and silence substantial fragments of the genome. Brief inactivation of Rho affects over 500 transcripts enriched for genes of foreign DNA elements and bacterial virulence factors. Prolonged inactivation of Rho causes extensive pervasive transcription, a genome-wide increase in antisense transcripts, and a rapid loss of viability of replicating and non-replicating M. tuberculosis in vitro and during acute and chronic infection in mice. Collectively, these data suggest that inhibition of Rho may provide an alternative strategy to treat tuberculosis with an efficacy similar to inhibition of RNA polymerase.
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Affiliation(s)
- Laure Botella
- Department of Microbiology and Immunology, Weill Cornell Medicine, 413E 69th Street, New York, New York 10021, USA
| | - Julien Vaubourgeix
- Department of Microbiology and Immunology, Weill Cornell Medicine, 413E 69th Street, New York, New York 10021, USA
| | - Jonathan Livny
- Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, Massachusetts 02142, USA
| | - Dirk Schnappinger
- Department of Microbiology and Immunology, Weill Cornell Medicine, 413E 69th Street, New York, New York 10021, USA
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Glyoxylate detoxification is an essential function of malate synthase required for carbon assimilation in Mycobacterium tuberculosis. Proc Natl Acad Sci U S A 2017; 114:E2225-E2232. [PMID: 28265055 DOI: 10.1073/pnas.1617655114] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The glyoxylate shunt is a metabolic pathway of bacteria, fungi, and plants used to assimilate even-chain fatty acids (FAs) and has been implicated in persistence of Mycobacterium tuberculosis (Mtb). Recent work, however, showed that the first enzyme of the glyoxylate shunt, isocitrate lyase (ICL), may mediate survival of Mtb during the acute and chronic phases of infection in mice through physiologic functions apart from fatty acid metabolism. Here, we report that malate synthase (MS), the second enzyme of the glyoxylate shunt, is essential for in vitro growth and survival of Mtb on even-chain fatty acids, in part, for a previously unrecognized activity: mitigating the toxicity of glyoxylate excess arising from metabolism of even-chain fatty acids. Metabolomic profiling revealed that MS-deficient Mtb cultured on fatty acids accumulated high levels of the ICL aldehyde endproduct, glyoxylate, and increased levels of acetyl phosphate, acetoacetyl coenzyme A (acetoacetyl-CoA), butyryl CoA, acetoacetate, and β-hydroxybutyrate. These changes were indicative of a glyoxylate-induced state of oxaloacetate deficiency, acetate overload, and ketoacidosis. Reduction of intrabacterial glyoxylate levels using a chemical inhibitor of ICL restored growth of MS-deficient Mtb, despite inhibiting entry of carbon into the glyoxylate shunt. In vivo depletion of MS resulted in sterilization of Mtb in both the acute and chronic phases of mouse infection. This work thus identifies glyoxylate detoxification as an essential physiologic function of Mtb malate synthase and advances its validation as a target for drug development.
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Effects of Increasing the Affinity of CarD for RNA Polymerase on Mycobacterium tuberculosis Growth, rRNA Transcription, and Virulence. J Bacteriol 2017; 199:JB.00698-16. [PMID: 27920294 DOI: 10.1128/jb.00698-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/23/2016] [Indexed: 01/29/2023] Open
Abstract
CarD is an essential RNA polymerase (RNAP) interacting protein in Mycobacterium tuberculosis that stimulates formation of RNAP-promoter open complexes. CarD plays a complex role in M. tuberculosis growth and virulence that is not fully understood. Therefore, to gain further insight into the role of CarD in M. tuberculosis growth and virulence, we determined the effect of increasing the affinity of CarD for RNAP. Using site-directed mutagenesis guided by crystal structures of CarD bound to RNAP, we identified amino acid substitutions that increase the affinity of CarD for RNAP. Using these substitutions, we show that increasing the affinity of CarD for RNAP increases the stability of the CarD protein in M. tuberculosis In addition, we show that increasing the affinity of CarD for RNAP increases the growth rate in M. tuberculosis without affecting 16S rRNA levels. We further show that increasing the affinity of CarD for RNAP reduces M. tuberculosis virulence in a mouse model of infection despite the improved growth rate in vitro Our findings suggest that the CarD-RNAP interaction protects CarD from proteolytic degradation in M. tuberculosis, establish that growth rate and rRNA levels can be uncoupled in M. tuberculosis and demonstrate that the strength of the CarD-RNAP interaction has been finely tuned to optimize virulence. IMPORTANCE Mycobacterium tuberculosis, the causative agent of tuberculosis, remains a major global health problem. In order to develop new strategies to battle this pathogen, we must gain a better understanding of the molecular processes involved in its survival and pathogenesis. We have previously identified CarD as an essential transcriptional regulator in mycobacteria. In this study, we detail the effects of increasing the affinity of CarD for RNAP on transcriptional regulation, CarD protein stability, and virulence. These studies expand our understanding of the global transcription regulator CarD, provide insight into how CarD activity is regulated, and broaden our understanding of prokaryotic transcription.
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Boot M, Sparrius M, Jim KK, Commandeur S, Speer A, van de Weerd R, Bitter W. iniBAC induction Is Vitamin B12- and MutAB-dependent in Mycobacterium marinum. J Biol Chem 2016; 291:19800-19812. [PMID: 27474746 PMCID: PMC5025670 DOI: 10.1074/jbc.m116.724088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 07/01/2016] [Indexed: 01/29/2024] Open
Abstract
Tuberculosis can be treated with a 6-month regimen of antibiotics. Although the targets of most of the first-line antibiotics have been identified, less research has focused on the intrabacterial stress responses that follow upon treatment with antibiotics. Studying the roles of these stress genes may lead to the identification of crucial stress-coping mechanisms that can provide additional drug targets to increase treatment efficacy. A three-gene operon with unknown function that is strongly up-regulated upon treatment with isoniazid and ethambutol is the iniBAC operon. We have reproduced these findings and show that iniBAC genes are also induced in infected host cells, although with higher variability. Next, we set out to elucidate the genetic network that results in iniBAC induction in Mycobacterium marinum By transposon mutagenesis, we identified that the operon is highly induced by mutations in genes encoding enzymes of the vitamin B12 biosynthesis pathway and the vitamin B12-dependent methylmalonyl-CoA-mutase MutAB. Lipid analysis showed that a mutA::tn mutant has decreased phthiocerol dimycocerosates levels, suggesting a link between iniBAC induction and the production of methyl-branched lipids. Moreover, a similar screen in Mycobacterium bovis BCG identified that phthiocerol dimycocerosate biosynthesis mutants cause the up-regulation of iniBAC genes. Based on these data, we propose that iniBAC is induced in response to mutations that cause defects in the biosynthesis of methyl-branched lipids. The resulting metabolic stress caused by these mutations or caused by ethambutol or isoniazid treatment may be relieved by iniBAC to increase the chance of bacterial survival.
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Affiliation(s)
- Maikel Boot
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Marion Sparrius
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Kin Ki Jim
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Susanna Commandeur
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Alexander Speer
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Robert van de Weerd
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
| | - Wilbert Bitter
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De Boelelaan 1108, 1081 HZ, Amsterdam, The Netherlands
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Prigozhin DM, Papavinasasundaram KG, Baer CE, Murphy KC, Moskaleva A, Chen TY, Alber T, Sassetti CM. Structural and Genetic Analyses of the Mycobacterium tuberculosis Protein Kinase B Sensor Domain Identify a Potential Ligand-binding Site. J Biol Chem 2016; 291:22961-22969. [PMID: 27601474 DOI: 10.1074/jbc.m116.731760] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 11/06/2022] Open
Abstract
Monitoring the environment with serine/threonine protein kinases is critical for growth and survival of Mycobacterium tuberculosis, a devastating human pathogen. Protein kinase B (PknB) is a transmembrane serine/threonine protein kinase that acts as an essential regulator of mycobacterial growth and division. The PknB extracellular domain (ECD) consists of four repeats homologous to penicillin-binding protein and serine/threonine kinase associated (PASTA) domains, and binds fragments of peptidoglycan. These properties suggest that PknB activity is modulated by ECD binding to peptidoglycan substructures, however, the molecular mechanisms underpinning PknB regulation remain unclear. In this study, we report structural and genetic characterization of the PknB ECD. We determined the crystal structures of overlapping ECD fragments at near atomic resolution, built a model of the full ECD, and discovered a region on the C-terminal PASTA domain that has the properties of a ligand-binding site. Hydrophobic interaction between this surface and a bound molecule of citrate was observed in a crystal structure. Our genetic analyses in M. tuberculosis showed that nonfunctional alleles were produced either by deletion of any of single PASTA domain or by mutation of individual conserved residues lining the putative ligand-binding surface of the C-terminal PASTA repeat. These results define two distinct structural features necessary for PknB signal transduction, a fully extended ECD and a conserved, membrane-distal putative ligand-binding site.
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Affiliation(s)
- Daniil M Prigozhin
- From the Department of Molecular and Cell Biology, QB3 Institute, University of California, Berkeley, California 94720-3220 and
| | - Kadamba G Papavinasasundaram
- the Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Christina E Baer
- the Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Kenan C Murphy
- the Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655
| | - Alisa Moskaleva
- From the Department of Molecular and Cell Biology, QB3 Institute, University of California, Berkeley, California 94720-3220 and
| | - Tony Y Chen
- From the Department of Molecular and Cell Biology, QB3 Institute, University of California, Berkeley, California 94720-3220 and
| | - Tom Alber
- From the Department of Molecular and Cell Biology, QB3 Institute, University of California, Berkeley, California 94720-3220 and
| | - Christopher M Sassetti
- the Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts 01655
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Boutte CC, Baer CE, Papavinasasundaram K, Liu W, Chase MR, Meniche X, Fortune SM, Sassetti CM, Ioerger TR, Rubin EJ. A cytoplasmic peptidoglycan amidase homologue controls mycobacterial cell wall synthesis. eLife 2016; 5. [PMID: 27304077 PMCID: PMC4946905 DOI: 10.7554/elife.14590] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/14/2016] [Indexed: 01/08/2023] Open
Abstract
Regulation of cell wall assembly is essential for bacterial survival and contributes to pathogenesis and antibiotic tolerance in Mycobacterium tuberculosis (Mtb). However, little is known about how the cell wall is regulated in stress. We found that CwlM, a protein homologous to peptidoglycan amidases, coordinates peptidoglycan synthesis with nutrient availability. Surprisingly, CwlM is sequestered from peptidoglycan (PG) by localization in the cytoplasm, and its enzymatic function is not essential. Rather, CwlM is phosphorylated and associates with MurA, the first enzyme in PG precursor synthesis. Phosphorylated CwlM activates MurA ~30 fold. CwlM is dephosphorylated in starvation, resulting in lower MurA activity, decreased cell wall metabolism, and increased tolerance to multiple antibiotics. A phylogenetic analysis of cwlM implies that localization in the cytoplasm drove the evolution of this factor. We describe a system that controls cell wall metabolism in response to starvation, and show that this regulation contributes to antibiotic tolerance.
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Affiliation(s)
- Cara C Boutte
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, United States
| | - Christina E Baer
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Kadamba Papavinasasundaram
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Weiru Liu
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, United States
| | - Michael R Chase
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, United States
| | - Xavier Meniche
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Sarah M Fortune
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, United States
| | - Christopher M Sassetti
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Thomas R Ioerger
- Department of Computer Science, Texas A and M University, Texas, United States
| | - Eric J Rubin
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, United States.,Department of Microbiology and Immunobiology, Harvard Medical School, Boston, United States
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Kirtania P, Ghosh S, Bhawsinghka N, Chakladar M, Das Gupta SK. Vitamin C induced DevR-dependent synchronization of Mycobacterium smegmatis growth and its effect on the proliferation of mycobacteriophage D29. FEMS Microbiol Lett 2016; 363:fnw097. [PMID: 27190284 DOI: 10.1093/femsle/fnw097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/12/2016] [Indexed: 01/18/2023] Open
Abstract
Vitamin C is known to inhibit mycobacterial growth by acting as a hypoxia inducing agent. While investigating how mycobacteriophage growth is influenced by hypoxic conditions induced by vitamin C, using Mycobacterium smegmatis- mycobacteriophage D29 as a model system, it was observed that prior exposure of the host to such conditions resulted in increased burst size of the phage. Vitamin C pre-exposure was also found to induce synchronous growth of the host. A mutant defective in DevR, the response regulator that controls hypoxic responses in mycobacteria, neither supported higher phage bursts nor was it able to undergo synchronized growth following vitamin C pre-exposure, indicating thereby that the two phenomena are interrelated. Further evidence supporting such an interrelationship was obtained from the observation that phage burst sizes varied depending on the stage of synchronous growth that the host cells were in, at the time of infection-higher bursts were observed in the resting/synthetic phases and lower in the dividing ones. The effects were specific in nature as synchronization by an unrelated method, known as 'crowding', did not lead to the same consequence. The results indicate that growth synchronization induced by vitamin C treatment is a DevR-dependent phenomenon which is exploited by mycobacteriophage D29 to grow in larger numbers.
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Affiliation(s)
- Prithwiraj Kirtania
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Shreya Ghosh
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Niketa Bhawsinghka
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Madhumita Chakladar
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Sujoy K Das Gupta
- Bose Institute, Department Of Microbiology, P1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
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van de Weerd R, Boot M, Maaskant J, Sparrius M, Verboom T, van Leeuwen LM, Burggraaf MJ, Paauw NJ, Dainese E, Manganelli R, Bitter W, Appelmelk BJ, Geurtsen J. Inorganic Phosphate Limitation Modulates Capsular Polysaccharide Composition in Mycobacteria. J Biol Chem 2016; 291:11787-99. [PMID: 27044743 DOI: 10.1074/jbc.m116.722454] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Indexed: 12/19/2022] Open
Abstract
Mycobacterium tuberculosis is protected by an unusual and highly impermeable cell envelope that is critically important for the successful colonization of the host. The outermost surface of this cell envelope is formed by capsular polysaccharides that play an important role in modulating the initial interactions once the bacillus enters the body. Although the bioenzymatic steps involved in the production of the capsular polysaccharides are emerging, information regarding the ability of the bacterium to modulate the composition of the capsule is still unknown. Here, we study the mechanisms involved in regulation of mycobacterial capsule biosynthesis using a high throughput screen for gene products involved in capsular α-glucan production. Utilizing this approach we identified a group of mutants that all carried mutations in the ATP-binding cassette phosphate transport locus pst These mutants collectively exhibited a strong overproduction of capsular polysaccharides, including α-glucan and arabinomannan, suggestive of a role for inorganic phosphate (Pi) metabolism in modulating capsular polysaccharide production. These findings were corroborated by the observation that growth under low Pi conditions as well as chemical activation of the stringent response induces capsule production in a number of mycobacterial species. This induction is, in part, dependent on σ factor E. Finally, we show that Mycobacterium marinum, a model organism for M. tuberculosis, encounters Pi stress during infection, which shows the relevance of our findings in vivo.
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Affiliation(s)
- Robert van de Weerd
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands,
| | - Maikel Boot
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Janneke Maaskant
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Marion Sparrius
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Theo Verboom
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Lisanne M van Leeuwen
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Maroeska J Burggraaf
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
| | - Nanne J Paauw
- Department of Molecular Cell Biology and Immunology, VU University Medical Center, P. O. Box 7057, 1007 MB Amsterdam, The Netherlands
| | - Elisa Dainese
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy
| | - Riccardo Manganelli
- Department of Molecular Medicine, University of Padova, Via Gabelli 63, 35121 Padova, Italy
| | - Wilbert Bitter
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands, Department of Molecular Microbiology, VU University Amsterdam, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands, and
| | - Ben J Appelmelk
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands,
| | - Jeroen Geurtsen
- From the Department of Medical Microbiology and Infection Control, VU University Medical Center, De boelelaan 1108, 1081HZ Amsterdam, The Netherlands
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Peptidoglycan synthesis in Mycobacterium tuberculosis is organized into networks with varying drug susceptibility. Proc Natl Acad Sci U S A 2015; 112:13087-92. [PMID: 26438867 DOI: 10.1073/pnas.1514135112] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peptidoglycan (PG), a complex polymer composed of saccharide chains cross-linked by short peptides, is a critical component of the bacterial cell wall. PG synthesis has been extensively studied in model organisms but remains poorly understood in mycobacteria, a genus that includes the important human pathogen Mycobacterium tuberculosis (Mtb). The principle PG synthetic enzymes have similar and, at times, overlapping functions. To determine how these are functionally organized, we carried out whole-genome transposon mutagenesis screens in Mtb strains deleted for ponA1, ponA2, and ldtB, major PG synthetic enzymes. We identified distinct factors required to sustain bacterial growth in the absence of each of these enzymes. We find that even the homologs PonA1 and PonA2 have unique sets of genetic interactions, suggesting there are distinct PG synthesis pathways in Mtb. Either PonA1 or PonA2 is required for growth of Mtb, but both genetically interact with LdtB, which has its own distinct genetic network. We further provide evidence that each interaction network is differentially susceptible to antibiotics. Thus, Mtb uses alternative pathways to produce PG, each with its own biochemical characteristics and vulnerabilities.
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Brown AC, Kokoczka R, Parish T. LytB1 and LytB2 of Mycobacterium tuberculosis Are Not Genetically Redundant. PLoS One 2015; 10:e0135638. [PMID: 26309039 PMCID: PMC4550268 DOI: 10.1371/journal.pone.0135638] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/23/2015] [Indexed: 11/26/2022] Open
Abstract
Mycobacterium tuberculosis synthesises isoprenoid precursors via the MEP/DOXP pathway and at least five enzymes in the pathway (Dxs1, Dxr/IspC, IspD, IspF, and GcpE/IspG) are required for growth in vitro. We investigated the role of LytB (IspH) in M. tuberculosis; M. tuberculosis is unusual in that it has two homologs–LytB1 and LytB2. We were unable to delete the lytB2 gene unless we provided an additional copy elsewhere, demonstrating that this is the essential homolog. We expressed lytB1 from the lytB2 promoter and confirmed that this could not complement for loss of function of lytB2, despite LytB1 possessing all the previously described conserved critical residues. Interestingly the sole LytB homolog of Mycobacterium smegmatis was able to compensate for loss of LytB2 in M. tuberculosis. We tested translational fusions of LytB1 and LytB2 for functionality in M. tuberculosis, but only a fusion with 90% N-terminal LytB2 and 10% C-terminal LytB1 was functional. In order to identify the key difference between the two proteins, site directed mutagenesis was used to change LytB2 residues into their counterparts in LytB1. None of these amino acid substitutions was essential for function and all lytB2 mutant alleles were functional. In contrast, mutation of the key residues for [Fe4S4] cluster formation, as well as a catalytic residue in LytB1 did not result in functional complementation. Thus, although LytB1 and LytB2 are not genetically redundant, this is not dependent on small amino acid changes, but is likely to be a result of major overall structural differences.
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Affiliation(s)
- Amanda Claire Brown
- Queen Mary University of London, London, E1 2AD, United Kingdom
- Barts & the London School of Medicine and Dentistry, London, E1 2AD, United Kingdom
| | - Rachel Kokoczka
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, 98102, United States of America
| | - Tanya Parish
- Queen Mary University of London, London, E1 2AD, United Kingdom
- Barts & the London School of Medicine and Dentistry, London, E1 2AD, United Kingdom
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, 98102, United States of America
- * E-mail:
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Kieser KJ, Boutte CC, Kester JC, Baer CE, Barczak AK, Meniche X, Chao MC, Rego EH, Sassetti CM, Fortune SM, Rubin EJ. Phosphorylation of the Peptidoglycan Synthase PonA1 Governs the Rate of Polar Elongation in Mycobacteria. PLoS Pathog 2015; 11:e1005010. [PMID: 26114871 PMCID: PMC4483258 DOI: 10.1371/journal.ppat.1005010] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 06/07/2015] [Indexed: 01/11/2023] Open
Abstract
Cell growth and division are required for the progression of bacterial infections. Most rod-shaped bacteria grow by inserting new cell wall along their mid-section. However, mycobacteria, including the human pathogen Mycobacterium tuberculosis, produce new cell wall material at their poles. How mycobacteria control this different mode of growth is incompletely understood. Here we find that PonA1, a penicillin binding protein (PBP) capable of transglycosylation and transpeptidation of cell wall peptidoglycan (PG), is a major governor of polar growth in mycobacteria. PonA1 is required for growth of Mycobacterium smegmatis and is critical for M. tuberculosis during infection. In both cases, PonA1’s catalytic activities are both required for normal cell length, though loss of transglycosylase activity has a more pronounced effect than transpeptidation. Mutations that alter the amount or the activity of PonA1 result in abnormal formation of cell poles and changes in cell length. Moreover, altered PonA1 activity results in dramatic differences in antibiotic susceptibility, suggesting that a balance between the two enzymatic activities of PonA1 is critical for survival. We also find that phosphorylation of a cytoplasmic region of PonA1 is required for normal activity. Mutations in a critical phosphorylated residue affect transglycosylase activity and result in abnormal rates of cell elongation. Together, our data indicate that PonA1 is a central determinant of polar growth in mycobacteria, and its governance of cell elongation is required for robust cell fitness during both host-induced and antibiotic stress. Bacterial infections rely on continued bacterial growth. Studying cell growth is particularly important for pathogens such as Mycobacterium tuberculosis that grow differently than model organisms. Unlike Escherichia coli or Bacillus subtilis, which grow by incorporating cell wall material along their body, mycobacteria grow from the pole. It remains unclear how mycobacteria construct and extend their poles. Our work identifies a cell wall synthase, PonA1, as a key determinant of mycobacterial polar growth. PonA1 governs polar growth through two enzymatic activities that build the cell wall’s peptidoglycan (PG); both of these activities are required for normal cell growth. Changes in the amount or activity of PonA1 leads to misplaced cell poles and inhibition of cell proliferation. PonA1 is phosphorylated, an unusual modification for PG synthases. This phosphorylation tunes the rate of cell elongation. Changing PonA1’s regulatory or enzymatic activity impacts the survival of cells in the host or when treated with antibiotics. Our work shows how mycobacterial cell pole construction and cell fitness is governed by a major cell wall synthase; these findings may have implications for other bacteria that elongate from their poles.
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Affiliation(s)
- Karen J. Kieser
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Cara C. Boutte
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Jemila C. Kester
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Christina E. Baer
- Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Amy K. Barczak
- Division of Infectious Disease, Massachusetts General Hospital, Boston, Massachusetts, United States of America
| | - Xavier Meniche
- Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Michael C. Chao
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - E. Hesper Rego
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Christopher M. Sassetti
- Department of Microbiology and Physiological Systems, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Sarah M. Fortune
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Eric J. Rubin
- Department of Immunology and Infectious Disease, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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44
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Ates LS, Ummels R, Commandeur S, van der Weerd R, Sparrius M, Weerdenburg E, Alber M, Kalscheuer R, Piersma SR, Abdallah AM, Abd El Ghany M, Abdel-Haleem AM, Pain A, Jiménez CR, Bitter W, Houben EN. Essential Role of the ESX-5 Secretion System in Outer Membrane Permeability of Pathogenic Mycobacteria. PLoS Genet 2015; 11:e1005190. [PMID: 25938982 PMCID: PMC4418733 DOI: 10.1371/journal.pgen.1005190] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 04/02/2015] [Indexed: 12/03/2022] Open
Abstract
Mycobacteria possess different type VII secretion (T7S) systems to secrete proteins across their unusual cell envelope. One of these systems, ESX-5, is only present in slow-growing mycobacteria and responsible for the secretion of multiple substrates. However, the role of ESX-5 substrates in growth and/or virulence is largely unknown. In this study, we show that esx-5 is essential for growth of both Mycobacterium marinum and Mycobacterium bovis. Remarkably, this essentiality can be rescued by increasing the permeability of the outer membrane, either by altering its lipid composition or by the introduction of the heterologous porin MspA. Mutagenesis of the first nucleotide-binding domain of the membrane ATPase EccC5 prevented both ESX-5-dependent secretion and bacterial growth, but did not affect ESX-5 complex assembly. This suggests that the rescuing effect is not due to pores formed by the ESX-5 membrane complex, but caused by ESX-5 activity. Subsequent proteomic analysis to identify crucial ESX-5 substrates confirmed that all detectable PE and PPE proteins in the cell surface and cell envelope fractions were routed through ESX-5. Additionally, saturated transposon-directed insertion-site sequencing (TraDIS) was applied to both wild-type M. marinum cells and cells expressing mspA to identify genes that are not essential anymore in the presence of MspA. This analysis confirmed the importance of esx-5, but we could not identify essential ESX-5 substrates, indicating that multiple of these substrates are together responsible for the essentiality. Finally, examination of phenotypes on defined carbon sources revealed that an esx-5 mutant is strongly impaired in the uptake and utilization of hydrophobic carbon sources. Based on these data, we propose a model in which the ESX-5 system is responsible for the transport of cell envelope proteins that are required for nutrient uptake. These proteins might in this way compensate for the lack of MspA-like porins in slow-growing mycobacteria.
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Affiliation(s)
- Louis S. Ates
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Roy Ummels
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Susanna Commandeur
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Robert van der Weerd
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Marion Sparrius
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Eveline Weerdenburg
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
| | - Marina Alber
- Institute for Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Rainer Kalscheuer
- Institute for Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Sander R. Piersma
- Department of Medical Oncology, OncoProteomics Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | - Abdallah M. Abdallah
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Moataz Abd El Ghany
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Alyaa M. Abdel-Haleem
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Arnab Pain
- Biological and Environmental Sciences and Engineering (BESE) division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Connie R. Jiménez
- Department of Medical Oncology, OncoProteomics Laboratory, VU University Medical Center, Amsterdam, the Netherlands
| | - Wilbert Bitter
- Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, the Netherlands
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Edith N.G. Houben
- Section Molecular Microbiology, Amsterdam Institute of Molecules, Medicine & Systems, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
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45
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Gopinath K, Warner DF, Mizrahi V. Targeted gene knockout and essentiality testing by homologous recombination. Methods Mol Biol 2015; 1285:131-149. [PMID: 25779314 DOI: 10.1007/978-1-4939-2450-9_8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This chapter provides an updated experimental protocol for generating allelic exchange mutants of mycobacteria by two-step selection using the p2NIL/pGOAL system. The types of mutants that can be generated using this approach are targeted gene knockouts marked with a drug resistance gene, unmarked deletion mutants, or strains in which a point mutation/s has been introduced into the target gene. A method for assessing the essentiality of a gene for mycobacterial growth by means of allelic exchange is also described. This method, which utilizes a merodiploid strain carrying a second copy of the gene of interest on an integration vector, allows the exploration by means of complement switching of structure-function relationships in proteins that are essential for mycobacterial growth.
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Affiliation(s)
- Krishnamoorthy Gopinath
- MRC/NHLS/UCT Molecular Mycobacteriology Research Unit and DST/NRF Centre of Excellence for Biomedical TB Research, Institute of Infectious Disease and Molecular Medicine and Department of Clinical Laboratory Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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46
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Abstract
High-efficiency transformation of DNA is integral to the study of mycobacteria, allowing genetic manipulation. Electroporation is the most widely used method for introducing DNA into mycobacterial strains. Many parameters contribute to high-efficiency transformation; these include the species per strain, the transforming DNA, the selectable marker, the growth medium additives, and the conditions of electroporation. In this chapter we provide an optimized method for the transformation of representative slow- and fast-growing species of mycobacteria-Mycobacterium tuberculosis and M. smegmatis, respectively.
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Affiliation(s)
- Renan Goude
- University of Rennes, Campus scientifique de Beaulieu, Rennes, France
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47
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Abstract
By definition, essential genes are fundamental to bacterial growth, yet the functions of many such genes remain unknown. Essential genes furthermore are central to the activity of most antibacterial drugs and among the most attractive targets for the development of new therapeutics. This chapter describes how synthetic genetic switches that utilize transcriptional repression, controlled proteolysis, or both to silence gene activity can be applied to construct and characterize conditional knockdown (cKD) mutants for essential genes in Mycobacterium smegmatis and Mycobacterium tuberculosis.
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48
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Korkegian A, Roberts DM, Blair R, Parish T. Mutations in the essential arabinosyltransferase EmbC lead to alterations in Mycobacterium tuberculosis lipoarabinomannan. J Biol Chem 2014; 289:35172-81. [PMID: 25352598 DOI: 10.1074/jbc.m114.583112] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Mycobacterium tuberculosis cell wall is a complex structure essential for the viability of the organism and its interaction with the host. The glycolipid lipoarabinomannan (LAM) plays an important role in mediating host-bacteria interactions and is involved in modulation of the immune response. The arabinosyltransferase EmbC required for LAM biosynthesis is essential. We constructed recombinant strains of M. tuberculosis expressing a variety of alleles of EmbC. We demonstrated that EmbC has a functional signal peptide in M. tuberculosis. Over- or underexpression of EmbC resulted in reduced or increased sensitivity to ethambutol, respectively. The C-terminal domain of EmbC was essential for activity because truncated alleles were unable to mediate LAM production in Mycobacterium smegmatis and were unable to complement an embC deletion in M. tuberculosis. The C-terminal domain of the closely related arabinosyltransferase EmbB was unable to complement the function of the EmbC C-terminal domain. Two functional motifs were identified. The GT-C motif contains two aspartate residues essential for function in the DDX motif. The proline-rich region contains two highly conserved asparagines (Asn-638 and Asn-652). Mutation of these residues was tolerated, but loss of Asn-638 resulted in the synthesis of truncated LAM, which appeared to lack arabinose branching. All embC alleles that were incapable of complementing LAM production in M. smegmatis were not viable in M. tuberculosis, supporting the hypothesis that LAM itself is essential in M. tuberculosis.
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Affiliation(s)
- Aaron Korkegian
- From TB Discovery Research, Infectious Disease Research Institute, Seattle, Washington 98102
| | - David M Roberts
- From TB Discovery Research, Infectious Disease Research Institute, Seattle, Washington 98102
| | - Rachel Blair
- From TB Discovery Research, Infectious Disease Research Institute, Seattle, Washington 98102
| | - Tanya Parish
- From TB Discovery Research, Infectious Disease Research Institute, Seattle, Washington 98102
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49
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Garner AL, Weiss LA, Manzano AR, Galburt EA, Stallings CL. CarD integrates three functional modules to promote efficient transcription, antibiotic tolerance, and pathogenesis in mycobacteria. Mol Microbiol 2014; 93:682-97. [PMID: 24962732 PMCID: PMC4127138 DOI: 10.1111/mmi.12681] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2014] [Indexed: 11/27/2022]
Abstract
Although the basic mechanisms of prokaryotic transcription are conserved, it has become evident that some bacteria require additional factors to allow for efficient gene transcription. CarD is an RNA polymerase (RNAP)-binding protein conserved in numerous bacterial species and essential in mycobacteria. Despite the importance of CarD, its function at transcription complexes remains unclear. We have generated a panel of mutations that individually target three independent functional modules of CarD: the RNAP interaction domain, the DNA-binding domain, and a conserved tryptophan residue. We have dissected the roles of each functional module in CarD activity and built a model where each module contributes to stabilizing RNAP-promoter complexes. Our work highlights the requirement of all three modules of CarD in the obligate pathogen Mycobacterium tuberculosis, but not in Mycobacterium smegmatis. We also report divergent use of the CarD functional modules in resisting oxidative stress and pigmentation. These studies provide new information regarding the functional domains involved in transcriptional regulation by CarD while also improving understanding of the physiology of M. tuberculosis.
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Affiliation(s)
- Ashley L. Garner
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110 USA
| | - Leslie A. Weiss
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110 USA
| | - Ana Ruiz Manzano
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, 63110 USA
| | - Eric A. Galburt
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, 63110 USA
| | - Christina L. Stallings
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110 USA
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50
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Abstract
ABSTRACT
Mycobacteriophages have provided numerous essential tools for mycobacterial genetics, including delivery systems for transposons, reporter genes, and allelic exchange substrates, and components for plasmid vectors and mutagenesis. Their genetically diverse genomes also reveal insights into the broader nature of the phage population and the evolutionary mechanisms that give rise to it. The substantial advances in our understanding of the biology of mycobacteriophages including a large collection of completely sequenced genomes indicates a rich potential for further contributions in tuberculosis genetics and beyond.
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