1
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Rothweiler U, Gundesø S, Mikalsen E, Svenning S, Singh M, Combes F, Pettersson F, Mangold A, Piotrowski Y, Schwab F, Lanes O, Striberny B. Using nucleolytic toxins as restriction enzymes enables new RNA applications. Nucleic Acids Res 2024; 52:e90. [PMID: 39271118 PMCID: PMC11472045 DOI: 10.1093/nar/gkae779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 08/20/2024] [Accepted: 08/28/2024] [Indexed: 09/15/2024] Open
Abstract
Over the past five decades, DNA restriction enzymes have revolutionized biotechnology. While these enzymes are widely used in DNA research and DNA engineering, the emerging field of RNA and mRNA therapeutics requires sequence-specific RNA endoribonucleases. Here, we describe EcoToxN1, a member of the type III toxin-antitoxin family of sequence-specific RNA endoribonucleases, and its use in RNA and mRNA analysis. This enzyme recognizes a specific pentamer in a single-stranded RNA and cleaves the RNA within this sequence. The enzyme is neither dependent on annealing of guide RNA or DNA oligos to the template nor does it require magnesium. Furthermore, it performs over a wide range of temperatures. With its unique functions and characteristics, EcoToxN1 can be classified as an RNA restriction enzyme. EcoToxN1 enables new workflows in RNA analysis and biomanufacturing, meeting the demand for faster, cheaper, and more robust analysis methods.
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Affiliation(s)
- Ulli Rothweiler
- ArcticZymes Technologies ASA, Sykehusveien 23, 9019 Tromsø, Norway
| | | | - Emma Wu Mikalsen
- ArcticZymes Technologies ASA, Sykehusveien 23, 9019 Tromsø, Norway
- UiT – The Arctic University of Norway, Faculty of Biosciences, Fisheries & Economics, Muninbakken 21, 9019 Tromsø, Norway
| | | | - Mahavir Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru 560012, India
| | - Francis Combes
- Department of Biotechnology and Nanomedicine, SINTEF AS, Richard Birkelands vei 3, N-7034 Trondheim, Norway
| | - Frida J Pettersson
- Department of Biotechnology and Nanomedicine, SINTEF AS, Richard Birkelands vei 3, N-7034 Trondheim, Norway
| | - Antonia Mangold
- ArcticZymes Technologies ASA, Sykehusveien 23, 9019 Tromsø, Norway
| | | | - Felix Schwab
- ArcticZymes Technologies ASA, Sykehusveien 23, 9019 Tromsø, Norway
| | - Olav Lanes
- ArcticZymes Technologies ASA, Sykehusveien 23, 9019 Tromsø, Norway
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2
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Liu Y, Li H, Dai D, He J, Liang Z. Gene Regulatory Mechanism of Mycobacterium Tuberculosis during Dormancy. Curr Issues Mol Biol 2024; 46:5825-5844. [PMID: 38921019 PMCID: PMC11203133 DOI: 10.3390/cimb46060348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 06/27/2024] Open
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) complex, is a zoonotic disease that remains one of the leading causes of death worldwide. Latent tuberculosis infection reactivation is a challenging obstacle to eradicating TB globally. Understanding the gene regulatory network of Mtb during dormancy is important. This review discusses up-to-date information about TB gene regulatory networks during dormancy, focusing on the regulation of lipid and energy metabolism, dormancy survival regulator (DosR), White B-like (Wbl) family, Toxin-Antitoxin (TA) systems, sigma factors, and MprAB. We outline the progress in vaccine and drug development associated with Mtb dormancy.
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Affiliation(s)
- Yiduo Liu
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
- College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Han Li
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
| | - Dejia Dai
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
| | - Jiakang He
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
| | - Zhengmin Liang
- College of Animal Science and Technology, Guangxi University, No. 100 University West Road, Nanning 530004, China (D.D.)
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3
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Broglia L, Le Rhun A, Charpentier E. Methodologies for bacterial ribonuclease characterization using RNA-seq. FEMS Microbiol Rev 2023; 47:fuad049. [PMID: 37656885 PMCID: PMC10503654 DOI: 10.1093/femsre/fuad049] [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: 03/23/2023] [Revised: 08/06/2023] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
Bacteria adjust gene expression at the post-transcriptional level through an intricate network of small regulatory RNAs and RNA-binding proteins, including ribonucleases (RNases). RNases play an essential role in RNA metabolism, regulating RNA stability, decay, and activation. These enzymes exhibit species-specific effects on gene expression, bacterial physiology, and different strategies of target recognition. Recent advances in high-throughput RNA sequencing (RNA-seq) approaches have provided a better understanding of the roles and modes of action of bacterial RNases. Global studies aiming to identify direct targets of RNases have highlighted the diversity of RNase activity and RNA-based mechanisms of gene expression regulation. Here, we review recent RNA-seq approaches used to study bacterial RNases, with a focus on the methods for identifying direct RNase targets.
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Affiliation(s)
- Laura Broglia
- Max Planck Unit for the Science of Pathogens, D-10117 Berlin, Germany
- Center for Human Technologies, Istituto Italiano di Tecnologia, 16152 Genova, Italy
| | - Anaïs Le Rhun
- Max Planck Unit for the Science of Pathogens, D-10117 Berlin, Germany
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, F-33000 Bordeaux, France
| | - Emmanuelle Charpentier
- Max Planck Unit for the Science of Pathogens, D-10117 Berlin, Germany
- Institute for Biology, Humboldt University, D-10115 Berlin, Germany
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4
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Bartelds MW, García-Blay Ó, Verhagen PGA, Wubbolts EJ, van Sluijs B, Heus HA, de Greef TFA, Huck WTS, Hansen MMK. Noise Minimization in Cell-Free Gene Expression. ACS Synth Biol 2023; 12:2217-2225. [PMID: 37478000 PMCID: PMC10443034 DOI: 10.1021/acssynbio.3c00174] [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: 03/24/2023] [Indexed: 07/23/2023]
Abstract
Biochemical reactions that involve small numbers of molecules are accompanied by a degree of inherent randomness that results in noisy reaction outcomes. In synthetic biology, the ability to minimize noise particularly during the reconstitution of future synthetic protocells is an outstanding challenge to secure robust and reproducible behavior. Here we show that by encapsulation of a bacterial cell-free gene expression system in water-in-oil droplets, in vitro-synthesized MazF reduces cell-free gene expression noise >2-fold. With stochastic simulations we identify that this noise minimization acts through both increased degradation and the autoregulatory feedback of MazF. Specifically, we find that the expression of MazF enhances the degradation rate of mRNA up to 18-fold in a sequence-dependent manner. This sequence specificity of MazF would allow targeted noise control, making it ideal to integrate into synthetic gene networks. Therefore, including MazF production in synthetic biology can significantly minimize gene expression noise, impacting future design principles of more complex cell-free gene circuits.
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Affiliation(s)
- Mart W. Bartelds
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Óscar García-Blay
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Pieter G. A. Verhagen
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Elise J. Wubbolts
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Bob van Sluijs
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Hans A. Heus
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Tom F. A. de Greef
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
- Laboratory
of Chemical Biology, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Institute
for Complex Molecular Systems, Eindhoven
University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Computational
Biology Group, Department of Biomedical Engineering, Eindhoven University of Technology,
P.O. Box 513, 5600 MB Eindhoven, The Netherlands
- Center
for Living Technologies, Eindhoven-Wageningen-Utrecht
Alliance, 5600 MB Eindhoven, The Netherlands
| | - Wilhelm T. S. Huck
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Maike M. K. Hansen
- Institute
for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
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5
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Choi W, Maharjan A, Im HG, Park JY, Park JT, Park JH. Identification and Characterization of HEPN-MNT Type II TA System from Methanothermobacter thermautotrophicus ΔH. J Microbiol 2023; 61:411-421. [PMID: 37071293 DOI: 10.1007/s12275-023-00041-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 04/19/2023]
Abstract
Toxin-antitoxin (TA) systems are widespread in bacteria and archaea plasmids and genomes to regulate DNA replication, gene transcription, or protein translation. Higher eukaryotic and prokaryotic nucleotide-binding (HEPN) and minimal nucleotidyltransferase (MNT) domains are prevalent in prokaryotic genomes and constitute TA pairs. However, three gene pairs (MTH304/305, 408/409, and 463/464) of Methanothermobacter thermautotropicus ΔH HEPN-MNT family have not been studied as TA systems. Among these candidates, our study characterizes the MTH463/MTH464 TA system. MTH463 expression inhibited Escherichia coli growth, whereas MTH464 did not and blocked MTH463 instead. Using site-directed MTH463 mutagenesis, we determined that amino acids R99G, H104A, and Y106A from the R[ɸX]4-6H motif are involved with MTH463 cell toxicity. Furthermore, we established that purified MTH463 could degrade MS2 phage RNA, whereas purified MTH464 neutralized MTH463 activity in vitro. Our results indicate that the endonuclease toxin MTH463 (encoding a HEPN domain) and its cognate antitoxin MTH464 (encoding the MNT domain) may act as a type II TA system in M. thermautotropicus ΔH. This study provides initial and essential information studying TA system functions, primarily archaea HEPN-MNT family.
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Affiliation(s)
- Wonho Choi
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, 28116, Republic of Korea
- 4D Convergence Technology Institute (National Key Technology Institute in University), Korea National University of Transportation, Jungpyeong, 27909, Republic of Korea
| | - Anoth Maharjan
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, 28116, Republic of Korea
| | - Hae Gang Im
- BIORCHESTRA Co., LTD., Daejeon, 34013, Republic of Korea
| | - Ji-Young Park
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, 28116, Republic of Korea
| | - Jong-Tae Park
- Department of Food Science and Technology, Chungnam National University, Daejeon, 34134, Republic of Korea.
| | - Jung-Ho Park
- Bio-Evaluation Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, 28116, Republic of Korea.
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6
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Hernández-Ramírez KC, Valle-Maldonado MI, Patiño-Medina JA, Calo S, Jácome-Galarza IE, Garre V, Meza-Carmen V, Ramírez-Díaz MI. Role of PumB antitoxin as a transcriptional regulator of the PumAB type-II toxin-antitoxin system and its endoribonuclease activity on the PumA (toxin) transcript. Mol Genet Genomics 2023; 298:455-472. [PMID: 36604348 DOI: 10.1007/s00438-022-01988-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 12/20/2022] [Indexed: 01/07/2023]
Abstract
The PumAB type-II toxin-antitoxin (TA) system is encoded by pumAB genes that are organized into an operon. This system is encoded by the pUM505 plasmid, isolated from a Pseudomonas aeruginosa clinical strain. The pumA gene encodes a putative RelE toxin protein (toxic component), whereas the pumB gene encodes a putative HTH antitoxin protein. The expression of the PumAB system in Escherichia coli confers plasmid stability. In addition, PumA toxin overexpression in P. aeruginosa possesses the capability to increase bacterial virulence, an effect that is neutralized by the PumB antitoxin. The aim of this study was to establish the mechanism of regulation of the PumAB toxin-antitoxin system from pUM505. By an in silico analysis of the putative regulatory elements, we identified two putative internal promoters, PpumB and PpumB-AlgU (in addition to the already reported PpumAB), located upstream of pumB. By RT-qPCR assays, we determined that the pumAB genes are transcribed differentially, in that the mRNA of pumB is more abundant than the pumA transcript. We also observed that pumB could be expressed individually and that its mRNA levels decreased under oxidative stress, during individual expression as well as co-expression of pumAB. However, under stressful conditions, the pumA mRNA levels were not affected. This suggests the negative regulation of pumB by stressful conditions. The PumB purified protein was found to bind to a DNA region located between the PpumAB and the pumA coding region, and PumA participates in PumB binding, suggesting that a PumA-PumB complex co-regulates the transcription of the pumAB operon. Interestingly, the pumA mRNA levels decreased after incubation in vitro with PumB protein. This effect was repressed by ribonuclease inhibitors, suggesting that PumB could function as an RNAse toward the mRNA of the toxin. Taken together, we conclude that the PumAB TA system possesses multiple mechanisms to regulate its expression, as well as that the PumB antitoxin generates a decrease in the mRNA toxin levels, suggesting an RNase function. Our analysis provides new insights into the understanding of the control of TA systems from mobile plasmid-encoded genes from a human pathogen.
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Affiliation(s)
- K C Hernández-Ramírez
- Laboratorio de Microbiología, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B-3, Ciudad Universitaria, 58030, Morelia, Michoacán, Mexico
| | - M I Valle-Maldonado
- Laboratorio de Diferenciación Celular, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Michoacán, Mexico.,Laboratorio Estatal de Salud Pública, Secretaría de Salud Michoacán, Morelia, Mexico
| | - J A Patiño-Medina
- Laboratorio de Diferenciación Celular, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Michoacán, Mexico
| | - S Calo
- School of Natural and Exact Sciences, Pontificia Universidad Católica Madre y Maestra, 51033, Santiago de los Caballeros, Dominican Republic
| | - I E Jácome-Galarza
- Laboratorio Estatal de Salud Pública, Secretaría de Salud Michoacán, Morelia, Mexico
| | - V Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, 30100, Murcia, Spain
| | - V Meza-Carmen
- Laboratorio de Diferenciación Celular, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Ciudad Universitaria, 58030, Morelia, Michoacán, Mexico
| | - M I Ramírez-Díaz
- Laboratorio de Microbiología, Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B-3, Ciudad Universitaria, 58030, Morelia, Michoacán, Mexico.
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7
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Golmoradi Zadeh R, Mirshekar M, Sadeghi Kalani B, Pourghader J, Barati M, Masjedian Jazi F. The expression of type II TA system genes following persister cell formation in Pseudomonas aeruginosa isolates in the exponential and stationary phases. Arch Microbiol 2022; 204:451. [PMID: 35781545 DOI: 10.1007/s00203-022-03038-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 05/30/2022] [Accepted: 06/01/2022] [Indexed: 11/02/2022]
Abstract
Failure of infection therapy in the presence of antibiotics has become a major problem which has been mostly attributed to the ability of bacterial persister cell formation. Bacteria use various mechanisms to form persister cells in different phases, among which is the toxin-antitoxin (TA) systems. This study aimed at investigating the expression of type II TA system genes under the stress of ciprofloxacin and colistin antibiotics in the exponential and stationary phases. To determine the effects of ciprofloxacin and colistin on persister cell formation in the exponential and stationary phases of Pseudomonas aeruginosa strains, colony counting was performed at different time intervals in the presence of fivefold MIC of ciprofloxacin and colistin. In addition, the expression of relBE, Xre-COG5654, vapBC, and Xre-GNAT genes in P. aeruginosa isolates was assessed 3.5 h after antibiotic treatment in the exponential and stationary phases using qRT-PCR. Our results indicated the presence of persister phenotype of P. aeruginosa strains in the presence of fivefold MIC of ciprofloxacin and colistin compared to the control after 3.5 h of incubation in the exponential and stationary phases. Also, the number of persister cells in the stationary phase was higher than that of the exponential phase. According to the results of qRT-PCR, ciprofloxacin and colistin may induce persister cells by increasing the expression of type II TA systems in stationary and exponential phases. Ciprofloxacin and colistin may increase the formation of persister cells by affecting the expression of type II TA systems.
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Affiliation(s)
- Rezvan Golmoradi Zadeh
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Maryam Mirshekar
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Behrooz Sadeghi Kalani
- Department of Microbiology, School of Medicine, Ilam University of Medical Science, Ilam, Iran.,Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Johar Pourghader
- Mechanical Engineering Department, Binghamton University, Binghamton, NY, 13902, USA
| | - Mahmood Barati
- Cellular and Molecular Research Center, Iran University of Medical Science, Tehran, Iran.,Department of Medical Biotechnology, Faculty of Allied Medicine, Iran University of Medical Science, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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8
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Thakur P, Atway J, Limbach PA, Addepalli B. RNA Cleavage Properties of Nucleobase-Specific RNase MC1 and Cusativin Are Determined by the Dinucleotide-Binding Interactions in the Enzyme-Active Site. Int J Mol Sci 2022; 23:7021. [PMID: 35806025 PMCID: PMC9266746 DOI: 10.3390/ijms23137021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 02/05/2023] Open
Abstract
Knowledge of the cleavage specificity of ribonucleases is critical for their application in RNA modification mapping or RNA-protein binding studies. Here, we detail the cleavage specificity and efficiency of ribonuclease MC1 and cusativin using a customized RNA sequence that contained all dinucleotide combinations and homopolymer sequences. The sequencing of the oligonucleotide digestion products by a semi-quantitative liquid chromatography coupled with mass spectrometry (LC-MS) analysis documented as little as 0.5-1% cleavage levels for a given dinucleotide sequence combination. While RNase MC1 efficiently cleaved the [A/U/C]pU dinucleotide bond, no cleavage was observed for the GpU bond. Similarly, cusativin efficiently cleaved Cp[U/A/G] dinucleotide combinations along with UpA and [A/U]pU, suggesting a broader specificity of dinucleotide preferences. The molecular interactions between the substrate and active site as determined by the dinucleotide docking studies of protein models offered additional evidence and support for the observed substrate specificity. Targeted alteration of the key amino acid residues in the nucleotide-binding site confirms the utility of this in silico approach for the identification of key interactions. Taken together, the use of bioanalytical and computational approaches, involving LC-MS and ligand docking of tertiary structural models, can form a powerful combination to help explain the RNA cleavage behavior of RNases.
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Affiliation(s)
| | | | | | - Balasubrahmanyam Addepalli
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA; (P.T.); (J.A.); (P.A.L.)
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9
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tRNA fMet Inactivating Mycobacterium tuberculosis VapBC Toxin-Antitoxin Systems as Therapeutic Targets. Antimicrob Agents Chemother 2022; 66:e0189621. [PMID: 35404073 DOI: 10.1128/aac.01896-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Mycobacterium tuberculosis genome contains an abundance of toxin-antitoxin (TA) systems, 50 of which belong to the VapBC family. The activity of VapC toxins is controlled by dynamic association with their cognate antitoxins-the toxin is inactive when complexed with VapB antitoxin but active when freed. Here, we determined the cellular target of two phylogenetically related VapC toxins and demonstrate how their properties can be harnessed for drug development. First, we used a specialized RNA sequencing (RNA-seq) approach, 5' RNA-seq, to accurately identify the in vivo RNA target of M. tuberculosis VapC2 and VapC21 toxins. Both toxins exclusively disable initiator tRNAfMet through cleavage at a single, identical site within their anticodon loop. Consistent with the essential role and global requirement for initiator tRNAfMet in bacteria, expression of each VapC toxin resulted in potent translation inhibition followed by growth arrest and cell death. Guided by previous structural studies, we then mutated two conserved amino acids in the antitoxin (WR→AA) that resided in the toxin-antitoxin interface and were predicted to inhibit toxin activity. Both mutants were markedly less efficient in rescuing growth over time, suggesting that screens for high-affinity small-molecule inhibitors against this or other crucial VapB-VapC interaction sites could drive constitutive inactivation of tRNAfMet by these VapC toxins. Collectively, the properties of the VapBC2 and VapBC21 TA systems provide a framework for development of bactericidal antitubercular agents with high specificity for M. tuberculosis cells.
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10
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Garcia Gonzalez J, Hernandez FJ. Nuclease activity: an exploitable biomarker in bacterial infections. Expert Rev Mol Diagn 2022; 22:265-294. [PMID: 35240900 DOI: 10.1080/14737159.2022.2049249] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION In the increasingly challenging field of clinical microbiology, diagnosis is a cornerstone whose accuracy and timing are crucial for the successful management, therapy, and outcome of infectious diseases. Currently employed biomarkers of infectious diseases define the scope and limitations of diagnostic techniques. As such, expanding the biomarker catalog is crucial to address unmet needs and bring about novel diagnostic functionalities and applications. AREAS COVERED This review describes the extracellular nucleases of 15 relevant bacterial pathogens and discusses the potential use of nuclease activity as a diagnostic biomarker. Articles were searched for in PubMed using terms: "nuclease", "bacteria", "nuclease activity" or "biomarker". For overview sections, original and review articles between 2000 and 2019 were searched for using terms: "infections", "diagnosis", "bacterial", "burden", "challenges". Informative articles were selected. EXPERT OPINION Using the catalytic activity of nucleases offers new possibilities compared to established biomarkers. Nucleic acid activatable reporters in combination with different transduction platforms and delivery methods can be used to detect disease-associated nuclease activity patterns in vitro and in vivo for prognostic and diagnostic applications. Even when these patterns are not obvious or of unknown etiology, screening platforms could be used to identify new disease reporters.
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Affiliation(s)
- Javier Garcia Gonzalez
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.,Wallenberg Centre for Molecular Medicine (WCMM), Linköping, Sweden.,Nucleic Acids Technologies Laboratory (NAT-lab), Linköping University, Linköping, Sweden
| | - Frank J Hernandez
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.,Wallenberg Centre for Molecular Medicine (WCMM), Linköping, Sweden.,Nucleic Acids Technologies Laboratory (NAT-lab), Linköping University, Linköping, Sweden
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11
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A hyperpromiscuous antitoxin protein domain for the neutralization of diverse toxin domains. Proc Natl Acad Sci U S A 2022; 119:2102212119. [PMID: 35121656 PMCID: PMC8832971 DOI: 10.1073/pnas.2102212119] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2021] [Indexed: 12/20/2022] Open
Abstract
Toxin–antitoxin systems are enigmatic and diverse elements of bacterial and bacteriophage genomes. We have uncovered remarkable versatility in an antitoxin protein domain that has evolved to neutralize dozens of different toxin domains. We find that antitoxins carrying this domain—Panacea—form complexes with their cognate toxins, indicating a direct neutralization mechanism, and that Panacea can be evolved to neutralize a noncognate and nonhomologous toxin with just two amino acid substitutions. This raises the possibility that this domain could be an adaptable universal or semi-universal protein neutralizer with significant biotechnological and medical potential. Toxin–antitoxin (TA) gene pairs are ubiquitous in microbial chromosomal genomes and plasmids as well as temperate bacteriophages. They act as regulatory switches, with the toxin limiting the growth of bacteria and archaea by compromising diverse essential cellular targets and the antitoxin counteracting the toxic effect. To uncover previously uncharted TA diversity across microbes and bacteriophages, we analyzed the conservation of genomic neighborhoods using our computational tool FlaGs (for flanking genes), which allows high-throughput detection of TA-like operons. Focusing on the widespread but poorly experimentally characterized antitoxin domain DUF4065, our in silico analyses indicated that DUF4065-containing proteins serve as broadly distributed antitoxin components in putative TA-like operons with dozens of different toxic domains with multiple different folds. Given the versatility of DUF4065, we have named the domain Panacea (and proteins containing the domain, PanA) after the Greek goddess of universal remedy. We have experimentally validated nine PanA-neutralized TA pairs. While the majority of validated PanA-neutralized toxins act as translation inhibitors or membrane disruptors, a putative nucleotide cyclase toxin from a Burkholderia prophage compromises transcription and translation as well as inducing RelA-dependent accumulation of the nucleotide alarmone (p)ppGpp. We find that Panacea-containing antitoxins form a complex with their diverse cognate toxins, characteristic of the direct neutralization mechanisms employed by Type II TA systems. Finally, through directed evolution, we have selected PanA variants that can neutralize noncognate TA toxins, thus experimentally demonstrating the evolutionary plasticity of this hyperpromiscuous antitoxin domain.
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12
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Sun H, Coussens NP, Danchik C, Wachsmuth LM, Henderson MJ, Patnaik S, Hall MD, Molinaro AL, Daines DA, Shen M. Discovery of Small-Molecule VapC1 Nuclease Inhibitors by Virtual Screening and Scaffold Hopping from an Atomic Structure Revealing Protein-Protein Interactions with a Native VapB1 Inhibitor. J Chem Inf Model 2022; 62:1249-1258. [PMID: 35103473 PMCID: PMC10041999 DOI: 10.1021/acs.jcim.1c01188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nontypeable Haemophilus influenzae (NTHi) are clinically important Gram-negative bacteria that are responsible for various human mucosal diseases, including otitis media (OM). Recurrent OM caused by NTHi is common, and infections that recur less than 2 weeks following antimicrobial therapy are largely attributable to the recurrence of the same strain of bacteria. Toxin-antitoxin (TA) modules encoded by bacteria enable rapid responses to environmental stresses and are thought to facilitate growth arrest, persistence, and tolerance to antibiotics. The vapBC-1 locus of NTHi encodes a type II TA system, comprising the ribonuclease toxin VapC1 and its cognate antitoxin VapB1. The activity of VapC1 has been linked to the survival of NTHi during antibiotic treatment both in vivo and ex vivo. Therefore, inhibitors of VapC1 might serve as adjuvants to antibiotics, preventing NTHi from entering growth arrest and surviving; however, none have been reported to date. A truncated VapB1 peptide from a crystal structure of the VapBC-1 complex was used to generate pharmacophore queries to facilitate a scaffold hopping approach for the identification of small-molecule VapC1 inhibitors. The National Center for Advancing Translational Sciences small-molecule library was virtually screened using the shape-based method rapid overlay of chemical structures (ROCS), and the top-ranking hits were docked into the VapB1 binding pocket of VapC1. Two hundred virtual screening hits with the best docking scores were selected and tested in a biochemical VapC1 activity assay, which confirmed eight compounds as VapC1 inhibitors. An additional 60 compounds were selected with structural similarities to the confirmed VapC1 inhibitors, of which 20 inhibited VapC1 activity. Intracellular target engagement of five inhibitors was indicated by the destabilization of VapC1 within bacterial cells from a cellular thermal shift assay; however, no impact on bacterial growth was observed. Thus, this virtual screening and scaffold hopping approach enabled the discovery of VapC1 ribonuclease inhibitors that might serve as starting points for preclinical development.
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Affiliation(s)
- Hongmao Sun
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Nathan P Coussens
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Carina Danchik
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Leah M Wachsmuth
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Mark J Henderson
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Samarjit Patnaik
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Matthew D Hall
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Ashley L Molinaro
- Office of the Dean, College of Sciences, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Dayle A Daines
- Office of the Dean, College of Sciences, Old Dominion University, Norfolk, Virginia 23529, United States
| | - Min Shen
- National Center for Advancing Translational Sciences (NCATS), 9800 Medical Center Drive, Rockville, Maryland 20850, United States
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13
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Shiao YH. Promising Assays for Examining a Putative Role of Ribosomal Heterogeneity in COVID-19 Susceptibility and Severity. Life (Basel) 2022; 12:203. [PMID: 35207490 PMCID: PMC8880406 DOI: 10.3390/life12020203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/17/2022] Open
Abstract
The heterogeneity of ribosomes, characterized by structural variations, arises from differences in types, numbers, and/or post-translational modifications of participating ribosomal proteins (RPs), ribosomal RNAs (rRNAs) sequence variants plus post-transcriptional modifications, and additional molecules essential for forming a translational machinery. The ribosomal heterogeneity within an individual organism or a single cell leads to preferential translations of selected messenger RNA (mRNA) transcripts over others, especially in response to environmental cues. The role of ribosomal heterogeneity in SARS-CoV-2 coronavirus infection, propagation, related symptoms, or vaccine responses is not known, and a technique to examine these has not yet been developed. Tools to detect ribosomal heterogeneity or to profile translating mRNAs independently cannot identify unique or specialized ribosome(s) along with corresponding mRNA substrate(s). Concurrent characterizations of RPs and/or rRNAs with mRNA substrate from a single ribosome would be critical to decipher the putative role of ribosomal heterogeneity in the COVID-19 disease, caused by the SARS-CoV-2, which hijacks the host ribosome to preferentially translate its RNA genome. Such a protocol should be able to provide a high-throughput screening of clinical samples in a large population that would reach a statistical power for determining the impact of a specialized ribosome to specific characteristics of the disease. These characteristics may include host susceptibility, viral infectivity and transmissibility, severity of symptoms, antiviral treatment responses, and vaccine immunogenicity including its side effect and efficacy. In this study, several state-of-the-art techniques, in particular, chemical probing of ribosomal components or rRNA structures, proximity ligation to generate rRNA-mRNA chimeras for sequencing, nanopore gating of individual ribosomes, nanopore RNA sequencing and/or structural analyses, single-ribosome mass spectrometry, and microfluidic droplets for separating ribosomes or indexing rRNAs/mRNAs, are discussed. The key elements for further improvement and proper integration of the above techniques to potentially arrive at a high-throughput protocol for examining individual ribosomes and their mRNA substrates in a clinical setting are also presented.
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Affiliation(s)
- Yih-Horng Shiao
- US Patent Trademark Office, Department of Commerce, Alexandria, VA 22314, USA
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14
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Cellular Memory of HipA-Induced Growth Arrest: The Length of Cell Growth Arrest Becomes Shorter for Each Successive Induction. Microorganisms 2021; 9:microorganisms9122594. [PMID: 34946194 PMCID: PMC8705531 DOI: 10.3390/microorganisms9122594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/04/2021] [Accepted: 12/11/2021] [Indexed: 11/17/2022] Open
Abstract
Toxin-antitoxin (TA) systems are genetic modules found commonly in bacterial genomes. HipA is a toxin protein encoded from the hipBA TA system in the genome of Escherichia coli. Ectopic expression of hipA induces cell growth arrest. Unlike the cell growth arrest caused by other TA toxins, cells resume growth from the HipA-induced cell growth arrest phase after a defined period of time. In this article, we describe the change in the length of growth arrest while cells undergo repeated cycles of hipA induction, growth arrest and regrowth phases. In the multiple conditions tested, we observed that the length of growth arrest became successively shorter for each round of induction. We verified that this was not due to the appearance of HipA-resistant mutants. Additionally, we identified conditions, such as the growth phase of the starting culture and growth vessels, that alter the length of growth arrest. Our results showed that the length of HipA-induced growth arrest was dependent on environmental factors-in particular, the past growth environment of cells, such as a previous hipA induction. These effects lasted even after multiple rounds of cell divisions, indicating the presence of cellular "memory" that impacts cells' response to HipA-induced toxicity.
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15
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Mycobacterium tuberculosis VapC4 toxin engages small ORFs to initiate an integrated oxidative and copper stress response. Proc Natl Acad Sci U S A 2021; 118:2022136118. [PMID: 34362841 DOI: 10.1073/pnas.2022136118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Mycobacterium tuberculosis (Mtb) VapBC4 toxin-antitoxin system is essential for the establishment of Mtb infection. Using a multitier, systems-level approach, we uncovered the sequential molecular events triggered by the VapC4 toxin that activate a circumscribed set of critical stress survival pathways which undoubtedly underlie Mtb virulence. VapC4 exclusively inactivated the sole transfer RNACys (tRNACys) through cleavage at a single site within the anticodon sequence. Depletion of the pool of tRNACys led to ribosome stalling at Cys codons within actively translating messenger RNAs. Genome mapping of these Cys-stalled ribosomes unexpectedly uncovered several unannotated Cys-containing open reading frames (ORFs). Four of these are small ORFs (sORFs) encoding Cys-rich proteins of fewer than 50 amino acids that function as Cys-responsive attenuators that engage ribosome stalling at tracts of Cys codons to control translation of downstream genes. Thus, VapC4 mimics a state of Cys starvation, which then activates Cys attenuation at sORFs to globally redirect metabolism toward the synthesis of free Cys. The resulting newly enriched pool of Cys feeds into the synthesis of mycothiol, the glutathione counterpart in this pathogen that is responsible for maintaining cellular redox homeostasis during oxidative stress, as well as into a circumscribed subset of cellular pathways that enable cells to defend against oxidative and copper stresses characteristically endured by Mtb within macrophages. Our ability to pinpoint activation or down-regulation of pathways that collectively align with Mtb virulence-associated stress responses and the nonreplicating persistent state brings to light a direct and vital role for the VapC4 toxin in mediating these critical pathways.
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16
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Feyh R, Waeber NB, Prinz S, Giammarinaro PI, Bange G, Hochberg G, Hartmann RK, Altegoer F. Structure and mechanistic features of the prokaryotic minimal RNase P. eLife 2021; 10:70160. [PMID: 34180399 PMCID: PMC8266387 DOI: 10.7554/elife.70160] [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: 05/07/2021] [Accepted: 06/25/2021] [Indexed: 12/17/2022] Open
Abstract
Endonucleolytic removal of 5'-leader sequences from tRNA precursor transcripts (pre-tRNAs) by ribonuclease P (RNase P) is essential for protein synthesis. Beyond RNA-based RNase P enzymes, protein-only versions of the enzyme exert this function in various eukarya (there termed PRORPs) and in some bacteria (Aquifex aeolicus and close relatives); both enzyme types belong to distinct subgroups of the PIN domain metallonuclease superfamily. Homologs of Aquifex RNase P (HARPs) are also expressed in some other bacteria and many archaea, where they coexist with RNA-based RNase P and do not represent the main RNase P activity. Here, we solved the structure of the bacterial HARP from Halorhodospira halophila by cryo-electron microscopy, revealing a novel screw-like dodecameric assembly. Biochemical experiments demonstrate that oligomerization is required for RNase P activity of HARPs. We propose that the tRNA substrate binds to an extended spike-helix (SH) domain that protrudes from the screw-like assembly to position the 5'-end in close proximity to the active site of the neighboring dimer. The structure suggests that eukaryotic PRORPs and prokaryotic HARPs recognize the same structural elements of pre-tRNAs (tRNA elbow region and cleavage site). Our analysis thus delivers the structural and mechanistic basis for pre-tRNA processing by the prokaryotic HARP system.
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Affiliation(s)
- Rebecca Feyh
- Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Nadine B Waeber
- Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Simone Prinz
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Pietro Ivan Giammarinaro
- Center for Synthetic Microbiology and Department of Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Gert Bange
- Center for Synthetic Microbiology and Department of Chemistry, Philipps-University Marburg, Marburg, Germany.,Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Georg Hochberg
- Center for Synthetic Microbiology and Department of Chemistry, Philipps-University Marburg, Marburg, Germany.,Max-Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Roland K Hartmann
- Institute of Pharmaceutical Chemistry, Philipps-University Marburg, Marburg, Germany
| | - Florian Altegoer
- Center for Synthetic Microbiology and Department of Chemistry, Philipps-University Marburg, Marburg, Germany
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17
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Sklyar T, Kurahina N, Lavrentieva K, Burlaka V, Lykholat T, Lykholat O. Autonomic (Mobile) Genetic Elements of Bacteria and Their Hierarchy. CYTOL GENET+ 2021. [DOI: 10.3103/s0095452721030099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Bezrukov F, Prados J, Renzoni A, Panasenko OO. MazF toxin causes alterations in Staphylococcus aureus transcriptome, translatome and proteome that underlie bacterial dormancy. Nucleic Acids Res 2021; 49:2085-2101. [PMID: 33544858 PMCID: PMC7913683 DOI: 10.1093/nar/gkaa1292] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/07/2020] [Accepted: 12/28/2020] [Indexed: 12/23/2022] Open
Abstract
Antibiotic resistance is a serious problem which may be caused by bacterial dormancy. It has been suggested that bacterial toxin-antitoxin systems induce dormancy. We analyzed the genome-wide role of Staphylococcus aureus endoribonuclease toxin MazF using RNA-Seq, Ribo-Seq and quantitative proteomics. We characterized changes in transcriptome, translatome and proteome caused by MazF, and proposed that MazF decreases translation directly by cleaving mRNAs, and indirectly, by decreasing translation factors and by promoting ribosome hibernation. Important pathways affected during the early stage of MazF induction were identified: MazF increases cell wall thickness and decreases cell division; MazF activates SsrA-system which rescues stalled ribosomes, appearing as a result of MazF mRNA cleavage. These pathways may be promising targets for new antibacterial drugs that prevent bacteria dormancy. Finally, we described the overall impact of MazF on S. aureus cell physiology, and propose one of the mechanisms by which MazF might regulate cellular changes leading to dormancy.
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Affiliation(s)
- Fedor Bezrukov
- Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
| | - Julien Prados
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Adriana Renzoni
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland.,Division of Infectious Diseases, Department of Medicine, Geneva University Hospitals and Medical School, Geneva 1211, Switzerland
| | - Olesya O Panasenko
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Geneva 1211, Switzerland
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19
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Srivastava A, Pati S, Kaushik H, Singh S, Garg LC. Toxin-antitoxin systems and their medical applications: current status and future perspective. Appl Microbiol Biotechnol 2021; 105:1803-1821. [PMID: 33582835 DOI: 10.1007/s00253-021-11134-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Almost all bacteria synthesize two types of toxins-one for its survival by regulating different cellular processes and another as a strategy to interact with host cells for pathogenesis. Usually, "bacterial toxins" are contemplated as virulence factors that harm the host organism. However, toxins produced by bacteria, as a survival strategy against the host, also hamper its cellular processes. To overcome this, the bacteria have evolved with the production of a molecule, referred to as antitoxin, to negate the deleterious effect of the toxin against itself. The toxin and antitoxins are encoded by a two-component toxin-antitoxin (TA) system. The antitoxin, a protein or RNA, sequesters the toxins of the TA system for neutralization within the bacterial cell. In this review, we have described different TA systems of bacteria and their potential medical and biotechnological applications. It is of interest to note that while bacterial toxin-antitoxin systems have been well studied, the TA system in unicellular eukaryotes, though predicted by the investigators, have never been paid the desired attention. In the present review, we have also touched upon the TA system of eukaryotes identified to date. KEY POINTS: Bacterial toxins harm the host and also affect the bacterial cellular processes. The antitoxin produced by bacteria protect it from the toxin's harmful effects. The toxin-antitoxin systems can be targeted for various medical applications.
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Affiliation(s)
- Akriti Srivastava
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201314, India
| | - Soumya Pati
- Department of Life Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida, Uttar Pradesh, 201314, India
| | - Himani Kaushik
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India
| | - Shailja Singh
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Lalit C Garg
- Gene Regulation Laboratory, National Institute of Immunology, New Delhi, 110067, India.
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20
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Functional and structural characterization of Deinococcus radiodurans R1 MazEF toxin-antitoxin system, Dr0416-Dr0417. J Microbiol 2021; 59:186-201. [DOI: 10.1007/s12275-021-0523-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/09/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022]
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21
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Wadie B, Abdel-Fattah MA, Yousef A, Mouftah SF, Elhadidy M, Salem TZ. In Silico Characterization of Toxin-Antitoxin Systems in Campylobacter Isolates Recovered from Food Sources and Sporadic Human Illness. Genes (Basel) 2021; 12:genes12010072. [PMID: 33430508 PMCID: PMC7826846 DOI: 10.3390/genes12010072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 11/16/2022] Open
Abstract
Campylobacter spp. represents the most common cause of gastroenteritis worldwide with the potential to cause serious sequelae. The ability of Campylobacter to survive stressful environmental conditions has been directly linked with food-borne illness. Toxin-antitoxin (TA) modules play an important role as defense systems against antimicrobial agents and are considered an invaluable strategy harnessed by bacterial pathogens to survive in stressful environments. Although TA modules have been extensively studied in model organisms such as Escherichia coli K12, the TA landscape in Campylobacter remains largely unexplored. Therefore, in this study, a comprehensive in silico screen of 111 Campylobacter (90 C.
jejuni and 21 C.
coli) isolates recovered from different food and clinical sources was performed. We identified 10 type II TA systems belonging to four TA families predicted in Campylobacter genomes. Furthermore, there was a significant association between the clonal population structure and distribution of TA modules; more specifically, most (12/13) of the Campylobacter isolates belonging to ST-21 isolates possess HicB-HicA TA modules. Finally, we observed a high degree of shared synteny among isolates bearing certain TA systems or even coexisting pairs of TA systems. Collectively, these findings provide useful insights about the distribution of TA modules in a heterogeneous pool of Campylobacter isolates from different sources, thus developing a better understanding regarding the mechanisms by which these pathogens survive stressful environmental conditions, which will further aid in the future designing of more targeted antimicrobials.
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Affiliation(s)
- Bishoy Wadie
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, October Gardens, 6th of October City, Giza 12578, Egypt; (B.W.); (A.Y.); (S.F.M.)
| | - Mohamed A. Abdel-Fattah
- Department of Agricultural Biotechnology, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt;
| | - Alshymaa Yousef
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, October Gardens, 6th of October City, Giza 12578, Egypt; (B.W.); (A.Y.); (S.F.M.)
| | - Shaimaa F. Mouftah
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, October Gardens, 6th of October City, Giza 12578, Egypt; (B.W.); (A.Y.); (S.F.M.)
| | - Mohamed Elhadidy
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, October Gardens, 6th of October City, Giza 12578, Egypt; (B.W.); (A.Y.); (S.F.M.)
- Department of Bacteriology, Mycology, and Immunology, Faculty of Veterinary Medicine, Mansoura University, Mansoura 35516, Egypt
- Correspondence: (M.E.); (T.Z.S.); Tel.: +20-1220786861 (M.E.); +20-1014114122 (T.Z.S.)
| | - Tamer Z. Salem
- Biomedical Sciences Program, University of Science and Technology, Zewail City of Science and Technology, October Gardens, 6th of October City, Giza 12578, Egypt; (B.W.); (A.Y.); (S.F.M.)
- Department of Microbial Genetics, AGERI, ARC, Giza 12619, Egypt
- Correspondence: (M.E.); (T.Z.S.); Tel.: +20-1220786861 (M.E.); +20-1014114122 (T.Z.S.)
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22
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Garcia B, Lee J, Edraki A, Hidalgo-Reyes Y, Erwood S, Mir A, Trost CN, Seroussi U, Stanley SY, Cohn RD, Claycomb JM, Sontheimer EJ, Maxwell KL, Davidson AR. Anti-CRISPR AcrIIA5 Potently Inhibits All Cas9 Homologs Used for Genome Editing. Cell Rep 2020; 29:1739-1746.e5. [PMID: 31722192 PMCID: PMC6910239 DOI: 10.1016/j.celrep.2019.10.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/24/2019] [Accepted: 10/03/2019] [Indexed: 11/03/2022] Open
Abstract
CRISPR-Cas9 systems provide powerful tools for genome editing. However, optimal employment of this technology will require control of Cas9 activity so that the timing, tissue specificity, and accuracy of editing may be precisely modulated. Anti-CRISPR proteins, which are small, naturally occurring inhibitors of CRISPR-Cas systems, are well suited for this purpose. A number of anti-CRISPR proteins have been shown to potently inhibit subgroups of CRISPR-Cas9 systems, but their maximal inhibitory activity is generally restricted to specific Cas9 homologs. Since Cas9 homologs vary in important properties, differing Cas9s may be optimal for particular genome-editing applications. To facilitate the practical exploitation of multiple Cas9 homologs, here we identify one anti-CRISPR, called AcrIIA5, that potently inhibits nine diverse type II-A and type II-C Cas9 homologs, including those currently used for genome editing. We show that the activity of AcrIIA5 results in partial in vivo cleavage of a single-guide RNA (sgRNA), suggesting that its mechanism involves RNA interaction.
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Affiliation(s)
- Bianca Garcia
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Jooyoung Lee
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Alireza Edraki
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Yurima Hidalgo-Reyes
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Steven Erwood
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada
| | - Aamir Mir
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Chantel N Trost
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Uri Seroussi
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Sabrina Y Stanley
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Ronald D Cohn
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada; Department of Pediatrics, University of Toronto and The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Julie M Claycomb
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Erik J Sontheimer
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA; Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Karen L Maxwell
- Department of Biochemistry, University of Toronto, Toronto, ON M5G 1M1, Canada.
| | - Alan R Davidson
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada; Department of Biochemistry, University of Toronto, Toronto, ON M5G 1M1, Canada.
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23
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Janczak M, Hyz K, Bukowski M, Lyzen R, Hydzik M, Wegrzyn G, Szalewska-Palasz A, Grudnik P, Dubin G, Wladyka B. Chromosomal localization of PemIK toxin-antitoxin system results in the loss of toxicity - Characterization of pemIK Sa1-Sp from Staphylococcus pseudintermedius. Microbiol Res 2020; 240:126529. [PMID: 32622987 DOI: 10.1016/j.micres.2020.126529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 06/11/2020] [Accepted: 06/12/2020] [Indexed: 11/20/2022]
Abstract
Toxin-antitoxin (TA) systems are ubiquitous in bacteria and on numerous occasions have been postulated to play a role in virulence of pathogens. Some Staphylococcus aureus strains carry a plasmid, which encodes the highly toxic PemIKSa TA system involved in maintenance of the plasmid but also implicated in modulation of gene expression. Here we showed that pemIKSa1-Sp TA system, homologous to the plasmid-encoded PemIKSa, is present in virtually each chromosome of S. pseudintermedius strain, however exhibits sequence heterogeneity. This results in two length variants of the PemKSa1-Sp toxin. The shorter (96 aa), C-terminally truncated toxin is enzymatically inactive, whereas the full length (112 aa) variant is an RNase, though nontoxic to the host cells. The lack of toxicity of the active PemKSa-Sp2 toxin is explained by increased substrate specificity. The pemISa1-Sp antitoxin gene seems pseudogenized, however, the whole pemIKSa1-Sp system is transcriptionally active. When production of N-terminally truncated antitoxins using alternative start codons is assumed, there are five possible length variants. Here we showed that even substantially truncated antitoxins are able to interact with PemKSa-Sp2 toxin and inhibit its RNase activity. Moreover, the antitoxins can rescue bacterial cells from toxic effects of overexpression of plasmid-encoded PemKSa toxin. Collectively, our data indicates that, contrary to the toxic plasmid-encoded PemIKSa TA system, location of pemIKSa1-Sp in the chromosome of S. pseudintermedius results in the loss of its toxicity. Interestingly, the retained RNase activity of PemKSa1-Sp2 toxin and functionality of the putative, N-terminally truncated antitoxins suggest the existence of evolutionary pressure for alleviation/mitigation of the toxin's toxicity and retention of the inhibitory activity of the antitoxin, respectively.
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Affiliation(s)
- Monika Janczak
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Karolina Hyz
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Michal Bukowski
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Robert Lyzen
- Intercollegiate Faculty of Biotechnology UG&MUG, University of Gdansk, Gdansk, Poland
| | - Marcin Hydzik
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland
| | - Grzegorz Wegrzyn
- Department of Molecular Biology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | | | - Przemyslaw Grudnik
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Grzegorz Dubin
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Benedykt Wladyka
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Krakow, Poland.
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Amraei F, Narimisa N, Sadeghi Kalani B, Lohrasbi V, Masjedian Jazi F. Persister cells formation and expression of type II Toxin-Antitoxin system genes in Brucella melitensis (16M) and Brucella abortus (B19). IRANIAN JOURNAL OF PATHOLOGY 2020; 15:127-133. [PMID: 32215028 PMCID: PMC7081757 DOI: 10.30699/ijp.2020.118902.2294] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 01/30/2020] [Indexed: 12/12/2022]
Abstract
Background & Objective: Persister cells are defined as a subpopulation of bacteria that are capable of reducing their metabolism and switching to dormancy in stress conditions. Persister cells formation has been attributed to numerous mechanisms, including stringent response and Toxin-Antitoxin (TA) systems. This study aimed to investigate the hypothetical role of TA systems in persister cells formation of Brucella strains by evaluating toxins of type II TA systems (RelE, Fic, BrnT, cogT) expression. Methods: Brucella strains treated with a lethal dose of gentamicin and ampicillin and to determine the number of surviving cells, bacterial colonies were counted at different time intervals. The role of TA systems in persister cell formation was then determined by toxin expression levels using qRT- PCR method. Results: Our results showed the viability of persister cells after 7 h. The results of relative qRT- PCR showed higher levels of toxin gene expression due to stress conditions, suggesting the possible role of TA systems in persister cells formation and antibiotics tolerance. Conclusion: The results of this study showed that considering the importance of persistence and the tolerance to antibiotics, further studies on persister cells formation and related genes such as the TA system genes in Brucella strains might help us to identify the precise mechanisms leading to persister cells formation.
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Affiliation(s)
- Fatemeh Amraei
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran.,Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Negar Narimisa
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran.,Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | | | - Vahid Lohrasbi
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran.,Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran.,Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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25
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Barth VC, Woychik NA. The Sole Mycobacterium smegmatis MazF Toxin Targets tRNA Lys to Impart Highly Selective, Codon-Dependent Proteome Reprogramming. Front Genet 2020; 10:1356. [PMID: 32117414 PMCID: PMC7033543 DOI: 10.3389/fgene.2019.01356] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 12/11/2019] [Indexed: 12/02/2022] Open
Abstract
Survival of mycobacteria, both free-living and host-dependent pathogenic species, is dependent on their ability to evade being killed by the stresses they routinely encounter. Toxin-antitoxin (TA) systems are unique to bacteria and archaea and are thought to function as stress survival proteins. Here, we study the activity of the endoribonuclease toxin derived from the MazEF TA system in Mycobacterium smegmatis, designated MazEF-ms. We first enlisted a specialized RNA-seq method, 5’ RNA-seq, to identify the primary RNA target(s) of the MazF-ms toxin. Just two tRNA species, tRNALys-UUU and tRNALys-CUU, were targeted for cleavage by MazF-ms at a single site within their anticodon sequence (UU↓U and CU↓U) to render these tRNAs nonfunctional for protein synthesis. The 5’ RNA-seq dataset also revealed hallmarks of ribosome stalling predominantly at Lys AAA codons even though both Lys tRNAs were cleaved by MazF-ms. Stalled ribosomes were then cleaved on their 5’ side by one or more RNases, resulting in very selective degradation of only those mRNAs harboring ribosomes stalled at Lys codons. This highly surgical, codon-dependent degradation of mRNA transcripts was validated using quantitative mass spectrometry of proteins that were newly synthesized during MazF-ms expression. The M. smegmatis proteome was altered as predicted, Lys AAA codon-rich proteins was downregulated while Lys AAA codon deficient proteins were upregulated. Analysis of specific subsets of proteins that were upregulated or downregulated was consistent with the growth-arrested phenotype of MazF-ms expressing cells. Curiously, the tRNA target and mechanism of action of MazF-ms paralleled that of one atypical MazF toxin in M. tuberculosis, suggesting manipulation of the levels of lysine tRNAs as the preferred conduit for reprogramming the proteomes via ribosome stalling at rare AAA codons in these GC-rich mycobacteria.
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Affiliation(s)
- Valdir Cristovao Barth
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Nancy A Woychik
- Department of Biochemistry and Molecular Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States.,Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, United States
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26
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A competence-regulated toxin-antitoxin system in Haemophilus influenzae. PLoS One 2020; 15:e0217255. [PMID: 31931516 PMCID: PMC6957337 DOI: 10.1371/journal.pone.0217255] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 12/16/2019] [Indexed: 12/28/2022] Open
Abstract
Natural competence allows bacteria to respond to environmental and nutritional cues by taking up free DNA from their surroundings, thus gaining both nutrients and genetic information. In the Gram-negative bacterium Haemophilus influenzae, the genes needed for DNA uptake are induced by the CRP and Sxy transcription factors in response to lack of preferred carbon sources and nucleotide precursors. Here we show that one of these genes, HI0659, encodes the antitoxin of a competence-regulated toxin-antitoxin operon (‘toxTA’), likely acquired by horizontal gene transfer from a Streptococcus species. Deletion of the putative toxin (HI0660) restores uptake to the antitoxin mutant. The full toxTA operon was present in only 17 of the 181 strains we examined; complete deletion was seen in 22 strains and deletions removing parts of the toxin gene in 142 others. In addition to the expected Sxy- and CRP-dependent-competence promoter, HI0659/660 transcript analysis using RNA-seq identified an internal antitoxin-repressed promoter whose transcription starts within toxT and will yield nonfunctional protein. We propose that the most likely effect of unopposed toxin expression is non-specific cleavage of mRNAs and arrest or death of competent cells in the culture. Although the high frequency of toxT and toxTA deletions suggests that this competence-regulated toxin-antitoxin system may be mildly deleterious, it could also facilitate downregulation of protein synthesis and recycling of nucleotides under starvation conditions. Although our analyses were focused on the effects of toxTA, the RNA-seq dataset will be a useful resource for further investigations into competence regulation.
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27
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Narimisa N, Amraei F, Kalani BS, Mohammadzadeh R, Jazi FM. Effects of sub-inhibitory concentrations of antibiotics and oxidative stress on the expression of type II toxin-antitoxin system genes in Klebsiella pneumoniae. J Glob Antimicrob Resist 2019; 21:51-56. [PMID: 31520807 DOI: 10.1016/j.jgar.2019.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 09/01/2019] [Accepted: 09/05/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Sub-inhibitory concentrations (sub-MICs) of antibiotics reflect the conditions that bacteria encounter in tissues and the natural environment. Sub-MICs of antibiotics can induce stress and alter the expression of different bacterial genes. Bacteria react to stress conditions using different mechanisms, one of which is the toxin-antitoxin (TA) system. This study investigated the expression of the TA system genes under oxidative and antibiotic stresses in Klebsiella pneumoniae (K. pneumoniae). METHODS To determine the effects of sub-MICs of gentamicin, nalidixic acid, ceftazidime, and certain concentrations of H2O2 on bacterial survival and growth, colony forming units were quantitated and turbidity was assessed following the treatment of K. pneumoniae with ½ MICs of antibiotics and 5 mM H2O2 at different time intervals. The expression of TA system genes in K. pneumoniae was evaluated 1 h after treatment using the quantitative real-time PCR (qRT-PCR) method. RESULTS The results revealed reduced K. pneumoniae growth in the presence of sub-MICs of antibiotics and 5 mM H2O2 compared to the control. Furthermore, according to the results of the qRT-PCR assay, only the presence of gentamicin could increase the expression of TA system genes. CONCLUSION Although the exact role of the TA systems in response to stress is still unclear, this study provided information on the effect of the type II TA systems under oxidative and antibiotic stress conditions.
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Affiliation(s)
- Negar Narimisa
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran; Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Amraei
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran; Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Behrooz Sadeghi Kalani
- Department of Medical Microbiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran; Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Rokhsareh Mohammadzadeh
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran; Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Faramarz Masjedian Jazi
- Microbial Biotechnology Research Center, Iran University of Medical Science, Tehran, Iran; Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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28
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Gordeeva J, Morozova N, Sierro N, Isaev A, Sinkunas T, Tsvetkova K, Matlashov M, Truncaite L, Morgan RD, Ivanov NV, Siksnys V, Zeng L, Severinov K. BREX system of Escherichia coli distinguishes self from non-self by methylation of a specific DNA site. Nucleic Acids Res 2019; 47:253-265. [PMID: 30418590 PMCID: PMC6326788 DOI: 10.1093/nar/gky1125] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 10/24/2018] [Indexed: 01/09/2023] Open
Abstract
Prokaryotes evolved numerous systems that defend against predation by bacteriophages. In addition to well-known restriction-modification and CRISPR-Cas immunity systems, many poorly characterized systems exist. One class of such systems, named BREX, consists of a putative phosphatase, a methyltransferase and four other proteins. A Bacillus cereus BREX system provides resistance to several unrelated phages and leads to modification of specific motif in host DNA. Here, we study the action of BREX system from a natural Escherichia coli isolate. We show that while it makes cells resistant to phage λ infection, induction of λ prophage from cells carrying BREX leads to production of viruses that overcome the defense. The induced phage DNA contains a methylated adenine residue in a specific motif. The same modification is found in the genome of BREX-carrying cells. The results establish, for the first time, that immunity to BREX system defense is provided by an epigenetic modification.
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Affiliation(s)
- Julia Gordeeva
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia
| | - Natalya Morozova
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Peter the Great St Petersburg State Polytechnic University, St Petersburg 195251, Russia
| | - Nicolas Sierro
- Philip Morris International R&D, Philip Morris Products S.A., Neuchâtel 2000, Switzerland
| | - Artem Isaev
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia
| | - Tomas Sinkunas
- Institute of Biotechnology, Vilnius University, Sauletekio Avenue 7, Vilnius 10257, Lithuania
| | - Ksenia Tsvetkova
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia
| | | | - Lidija Truncaite
- Institute of Biochemistry, Vilnius University, Sauletekio Avenue 7, Vilnius 10257, Lithuania
| | | | - Nikolai V Ivanov
- Philip Morris International R&D, Philip Morris Products S.A., Neuchâtel 2000, Switzerland
| | - Virgis Siksnys
- Institute of Biotechnology, Vilnius University, Sauletekio Avenue 7, Vilnius 10257, Lithuania
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Konstantin Severinov
- Skolkovo Institute of Science and Technology, Moscow 143028, Russia.,Peter the Great St Petersburg State Polytechnic University, St Petersburg 195251, Russia.,Waksman Institute of Microbiology, Piscataway, NJ 08854, USA
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29
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Bervoets I, Charlier D. Diversity, versatility and complexity of bacterial gene regulation mechanisms: opportunities and drawbacks for applications in synthetic biology. FEMS Microbiol Rev 2019; 43:304-339. [PMID: 30721976 PMCID: PMC6524683 DOI: 10.1093/femsre/fuz001] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 01/21/2019] [Indexed: 12/15/2022] Open
Abstract
Gene expression occurs in two essential steps: transcription and translation. In bacteria, the two processes are tightly coupled in time and space, and highly regulated. Tight regulation of gene expression is crucial. It limits wasteful consumption of resources and energy, prevents accumulation of potentially growth inhibiting reaction intermediates, and sustains the fitness and potential virulence of the organism in a fluctuating, competitive and frequently stressful environment. Since the onset of studies on regulation of enzyme synthesis, numerous distinct regulatory mechanisms modulating transcription and/or translation have been discovered. Mostly, various regulatory mechanisms operating at different levels in the flow of genetic information are used in combination to control and modulate the expression of a single gene or operon. Here, we provide an extensive overview of the very diverse and versatile bacterial gene regulatory mechanisms with major emphasis on their combined occurrence, intricate intertwinement and versatility. Furthermore, we discuss the potential of well-characterized basal expression and regulatory elements in synthetic biology applications, where they may ensure orthogonal, predictable and tunable expression of (heterologous) target genes and pathways, aiming at a minimal burden for the host.
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Affiliation(s)
- Indra Bervoets
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Daniel Charlier
- Research Group of Microbiology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
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30
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Toxin-mediated ribosome stalling reprograms the Mycobacterium tuberculosis proteome. Nat Commun 2019; 10:3035. [PMID: 31292443 PMCID: PMC6620280 DOI: 10.1038/s41467-019-10869-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 05/31/2019] [Indexed: 12/03/2022] Open
Abstract
Mycobacterium tuberculosis readily adapts to survive a wide range of assaults by modifying its physiology and establishing a latent tuberculosis (TB) infection. Here we report a sophisticated mode of regulation by a tRNA-cleaving toxin that enlists highly selective ribosome stalling to recalibrate the transcriptome and remodel the proteome. This toxin, MazF-mt9, exclusively inactivates one isoacceptor tRNA, tRNALys43-UUU, through cleavage at a single site within its anticodon (UU↓U). Because wobble rules preclude compensation for loss of tRNALys43-UUU by the second M. tuberculosis lysine tRNA, tRNALys19-CUU, ribosome stalling occurs at in-frame cognate AAA Lys codons. Consequently, the transcripts harboring these stalled ribosomes are selectively cleaved by specific RNases, leading to their preferential deletion. This surgically altered transcriptome generates concomitant changes to the proteome, skewing synthesis of newly synthesized proteins away from those rich in AAA Lys codons toward those harboring few or no AAA codons. This toxin-mediated proteome reprogramming may work in tandem with other pathways to facilitate M. tuberculosis stress survival. MazF endoribonucleases are thought to arrest growth of Mycobacterium tuberculosis by global translation inhibition. Here, Barth et al. show that MazF-mt9 cleaves a specific tRNA, leading to ribosome stalling at AAA codons and thus selective mRNA degradation and changes in transcriptome and proteome.
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31
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Schwarz TS, Wäber NB, Feyh R, Weidenbach K, Schmitz RA, Marchfelder A, Hartmann RK. Homologs of aquifex aeolicus protein-only RNase P are not the major RNase P activities in the archaea haloferax volcanii and methanosarcina mazei. IUBMB Life 2019; 71:1109-1116. [PMID: 31283101 DOI: 10.1002/iub.2122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/07/2019] [Accepted: 06/09/2019] [Indexed: 01/20/2023]
Abstract
The mature 5'-ends of tRNAs are generated by RNase P in all domains of life. The ancient form of the enzyme is a ribonucleoprotein consisting of a catalytic RNA and one or more protein subunits. However, in the hyperthermophilic bacterium Aquifex aeolicus and close relatives, RNase P is a protein-only enzyme consisting of a single type of polypeptide (Aq_880, ~23 kDa). In many archaea, homologs of Aq_880 were identified (termed HARPs for Homologs of Aquifex RNase P) in addition to the RNA-based RNase P, raising the question about the functions of HARP and the classical RNase P in these archaea. Here we investigated HARPs from two euryarchaeotes, Haloferax volcanii and Methanosarcina mazei. Archaeal strains with HARP gene knockouts showed no growth phenotypes under standard conditions, temperature and salt stress (H. volcanii) or nitrogen deficiency (M. mazei). Recombinant H. volcanii and M. mazei HARPs were basically able to catalyse specific tRNA 5'-end maturation in vitro. Furthermore, M. mazei HARP was able to rescue growth of an Escherichia coli RNase P depletion strain with comparable efficiency as Aq_880, while H. volcanii HARP was unable to do so. In conclusion, both archaeal HARPs showed the capacity (in at least one functional assay) to act as RNases P. However, the ease to obtain knockouts of the singular HARP genes and the lack of growth phenotypes upon HARP gene deletion contrasts with the findings that the canonical RNase P RNA gene cannot be deleted in H. volcanii, and a knockdown of RNase P RNA in H. volcanii results in severe tRNA processing defects. We conclude that archaeal HARPs do not make a major contribution to global tRNA 5'-end maturation in archaea, but may well exert a specialised, yet unknown function in (t)RNA metabolism. © 2019 IUBMB Life, 2019 © 2019 IUBMB Life, 71(8):1109-1116, 2019.
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Affiliation(s)
| | - Nadine B Wäber
- Institute of Pharmaceutical Chemistry, Philipps University, Marburg, Germany
| | - Rebecca Feyh
- Institute of Pharmaceutical Chemistry, Philipps University, Marburg, Germany
| | - Katrin Weidenbach
- Institute of General Microbiology, Christian-Albrechts-Universität, Kiel, Germany
| | - Ruth A Schmitz
- Institute of General Microbiology, Christian-Albrechts-Universität, Kiel, Germany
| | | | - Roland K Hartmann
- Institute of Pharmaceutical Chemistry, Philipps University, Marburg, Germany
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32
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Crystal Structure of VapBC-1 from Nontypeable Haemophilus influenzae and the Effect of PIN Domain Mutations on Survival during Infection. J Bacteriol 2019; 201:JB.00026-19. [PMID: 30936373 DOI: 10.1128/jb.00026-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 03/29/2019] [Indexed: 12/15/2022] Open
Abstract
Toxin-antitoxin (TA) gene pairs have been identified in nearly all bacterial genomes sequenced to date and are thought to facilitate persistence and antibiotic tolerance. TA loci are classified into various types based upon the characteristics of their antitoxins, with those in type II expressing proteic antitoxins. Many toxins from type II modules are ribonucleases that maintain a PilT N-terminal (PIN) domain containing conserved amino acids considered essential for activity. The vapBC (virulence-associated protein) TA system is the largest subfamily in this class and has been linked to pathogenesis of nontypeable Haemophilus influenzae (NTHi). In this study, the crystal structure of the VapBC-1 complex from NTHi was determined to 2.20 Å resolution. Based on this structure, aspartate-to-asparagine and glutamate-to-glutamine mutations of four conserved residues in the PIN domain of the VapC-1 toxin were constructed and the effects of the mutations on protein-protein interactions, growth of Escherichia coli, and pathogenesis ex vivo were tested. Finally, a novel model system was designed and utilized that consists of an NTHi ΔvapBC-1 strain complemented in cis with the TA module containing a mutated or wild-type toxin at an ectopic site on the chromosome. This enabled the analysis of the effect of PIN domain toxin mutants in tandem with their wild-type antitoxin under the control of the vapBC-1 native promoter and in single copy. This is the first report of a system facilitating the study of TA mutant operons in the background of NTHi during infections of primary human tissues ex vivo IMPORTANCE Herein the crystal structure of the VapBC-1 complex from nontypeable Haemophilus influenzae (NTHi) is described. Our results show that some of the mutations in the PIN domain of the VapC-1 toxin were associated with decreased toxicity in E. coli, but the mutants retained the ability to homodimerize and to heterodimerize with the wild-type cognate antitoxin, VapB-1. A new system was designed and constructed to quantify the effects of these mutations on NTHi survival during infections of primary human tissues ex vivo Any mutation to a conserved amino acid in the PIN domain significantly decreased the number of survivors compared to that of the in cis wild-type toxin under the same conditions.
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33
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Nikolic N. Autoregulation of bacterial gene expression: lessons from the MazEF toxin-antitoxin system. Curr Genet 2019; 65:133-138. [PMID: 30132188 PMCID: PMC6343021 DOI: 10.1007/s00294-018-0879-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/13/2018] [Accepted: 08/14/2018] [Indexed: 11/30/2022]
Abstract
Autoregulation is the direct modulation of gene expression by the product of the corresponding gene. Autoregulation of bacterial gene expression has been mostly studied at the transcriptional level, when a protein acts as the cognate transcriptional repressor. A recent study investigating dynamics of the bacterial toxin-antitoxin MazEF system has shown how autoregulation at both the transcriptional and post-transcriptional levels affects the heterogeneity of Escherichia coli populations. Toxin-antitoxin systems hold a crucial but still elusive part in bacterial response to stress. This perspective highlights how these modules can also serve as a great model system for investigating basic concepts in gene regulation. However, as the genomic background and environmental conditions substantially influence toxin activation, it is important to study (auto)regulation of toxin-antitoxin systems in well-defined setups as well as in conditions that resemble the environmental niche.
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Affiliation(s)
- Nela Nikolic
- Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria.
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34
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Mets T, Kasvandik S, Saarma M, Maiväli Ü, Tenson T, Kaldalu N. Fragmentation of Escherichia coli mRNA by MazF and MqsR. Biochimie 2019; 156:79-91. [DOI: 10.1016/j.biochi.2018.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 10/06/2018] [Indexed: 01/21/2023]
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35
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A Systematic Overview of Type II and III Toxin-Antitoxin Systems with a Focus on Druggability. Toxins (Basel) 2018; 10:toxins10120515. [PMID: 30518070 PMCID: PMC6315513 DOI: 10.3390/toxins10120515] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
Toxin-antitoxin (TA) systems are known to play various roles in physiological processes, such as gene regulation, growth arrest and survival, in bacteria exposed to environmental stress. Type II TA systems comprise natural complexes consisting of protein toxins and antitoxins. Each toxin and antitoxin participates in distinct regulatory mechanisms depending on the type of TA system. Recently, peptides designed by mimicking the interfaces between TA complexes showed its potential to activate the activity of toxin by competing its binding counterparts. Type II TA systems occur more often in pathogenic bacteria than in their nonpathogenic kin. Therefore, they can be possible drug targets, because of their high abundance in some pathogenic bacteria, such as Mycobacterium tuberculosis. In addition, recent bioinformatic analyses have shown that type III TA systems are highly abundant in the intestinal microbiota, and recent clinical studies have shown that the intestinal microbiota is linked to inflammatory diseases, obesity and even several types of cancer. We therefore focused on exploring the putative relationship between intestinal microbiota-related human diseases and type III TA systems. In this paper, we review and discuss the development of possible druggable materials based on the mechanism of type II and type III TA system.
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36
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Genotoxic, Metabolic, and Oxidative Stresses Regulate the RNA Repair Operon of Salmonella enterica Serovar Typhimurium. J Bacteriol 2018; 200:JB.00476-18. [PMID: 30201777 DOI: 10.1128/jb.00476-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/04/2018] [Indexed: 12/12/2022] Open
Abstract
The σ54 regulon in Salmonella enterica serovar Typhimurium includes a predicted RNA repair operon encoding homologs of the metazoan Ro60 protein (Rsr), Y RNAs (YrlBA), RNA ligase (RtcB), and RNA 3'-phosphate cyclase (RtcA). Transcription from σ54-dependent promoters requires that a cognate bacterial enhancer binding protein (bEBP) be activated by a specific environmental or cellular signal; the cognate bEBP for the σ54-dependent promoter of the rsr-yrlBA-rtcBA operon is RtcR. To identify conditions that generate the signal for RtcR activation in S Typhimurium, transcription of the RNA repair operon was assayed under multiple stress conditions that result in nucleic acid damage. RtcR-dependent transcription was highly induced by the nucleic acid cross-linking agents mitomycin C (MMC) and cisplatin, and this activation was dependent on RecA. Deletion of rtcR or rtcB resulted in decreased cell viability relative to that of the wild type following treatment with MMC. Oxidative stress from peroxide exposure also induced RtcR-dependent transcription of the operon. Nitrogen limitation resulted in RtcR-independent increased expression of the operon; the effect of nitrogen limitation required NtrC. The adjacent toxin-antitoxin module, dinJ-yafQ, was cotranscribed with the RNA repair operon but was not required for RtcR activation, although YafQ endoribonuclease activated RtcR-dependent transcription. Stress conditions shown to induce expression the RNA repair operon of Escherichia coli (rtcBA) did not stimulate expression of the S Typhimurium RNA repair operon. Similarly, MMC did not induce expression of the E. coli rtcBA operon, although when expressed in S Typhimurium, E. coli RtcR responds effectively to the unknown signal(s) generated there by MMC exposure.IMPORTANCE Homologs of the metazoan RNA repair enzymes RtcB and RtcA occur widely in eubacteria, suggesting a selective advantage. Although the enzymatic activities of the eubacterial RtcB and RtcA have been well characterized, the physiological roles remain largely unresolved. Here we report stress responses that activate expression of the σ54-dependent RNA repair operon (rsr-yrlBA-rtcBA) of S Typhimurium and demonstrate that expression of the operon impacts cell survival under MMC-induced stress. Characterization of the requirements for activation of this tightly regulated operon provides clues to the possible functions of operon components in vivo, enhancing our understanding of how this human pathogen copes with environmental stressors.
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37
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Slayden RA, Dawson CC, Cummings JE. Toxin-antitoxin systems and regulatory mechanisms in Mycobacterium tuberculosis. Pathog Dis 2018; 76:4969681. [PMID: 29788125 DOI: 10.1093/femspd/fty039] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/01/2018] [Indexed: 11/14/2022] Open
Abstract
There has been a significant reduction in annual tuberculosis incidence since the World Health Organization declared tuberculosis a global health threat. However, treatment of M. tuberculosis infections requires lengthy multidrug therapeutic regimens to achieve a durable cure. The development of new drugs that are active against resistant strains and phenotypically diverse organisms continues to present the greatest challenge in the future. Numerous phylogenomic analyses have revealed that the Mtb genome encodes a significantly expanded repertoire of toxin-antitoxin (TA) loci that makes up the Mtb TA system. A TA loci is a two-gene operon encoding a 'toxin' protein that inhibits bacterial growth and an interacting 'antitoxin' partner that neutralizes the inhibitory activity of the toxin. The presence of multiple chromosomally encoded TA loci in Mtb raises important questions in regard to expansion, regulation and function. Thus, the functional roles of TA loci in Mtb pathogenesis have received considerable attention over the last decade. The cumulative results indicate that they are involved in regulating adaptive responses to stresses associated with the host environment and drug treatment. Here we review the TA families encoded in Mtb, discuss the duplication of TA loci in Mtb, regulatory mechanism of TA loci, and phenotypic heterogeneity and pathogenesis.
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Affiliation(s)
- Richard A Slayden
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| | - Clinton C Dawson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
| | - Jason E Cummings
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-0922, USA
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38
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Miyamoto T, Yokota A, Ota Y, Tsuruga M, Aoi R, Tsuneda S, Noda N. Nitrosomonas europaea MazF Specifically Recognises the UGG Motif and Promotes Selective RNA Degradation. Front Microbiol 2018; 9:2386. [PMID: 30349517 PMCID: PMC6186784 DOI: 10.3389/fmicb.2018.02386] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/18/2018] [Indexed: 01/08/2023] Open
Abstract
Toxin-antitoxin (TA) systems are implicated in prokaryotic stress adaptation. Previously, bioinformatics analysis predicted that such systems are abundant in some slowly growing chemolithotrophs; e.g., Nitrosomonas europaea. Nevertheless, the molecular functions of these stress-response modules remain largely unclear, limiting insight regarding their physiological roles. Herein, we show that one of the putative MazF family members, encoded at the ALW85_RS04820 locus, constitutes a functional toxin that engenders a TA pair with its cognate MazE antitoxin. The coordinate application of a specialised RNA-Seq and a fluorescence quenching technique clarified that a unique triplet, UGG, serves as the determinant for MazF cleavage. Notably, statistical analysis predicted that two transcripts, which are unique in the autotroph, comprise the prime targets of the MazF endoribonuclease: hydroxylamine dehydrogenase (hao), which is essential for ammonia oxidation, and a large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcL), which plays an important role in carbon assimilation. Given that N. europaea obtains energy and reductants via ammonia oxidation and the carbon for its growth from carbon dioxide, the chemolithotroph might use the MazF endoribonuclease to modulate its translation profile and subsequent biochemical reactions.
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Affiliation(s)
- Tatsuki Miyamoto
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Akiko Yokota
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Yuri Ota
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Masako Tsuruga
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Rie Aoi
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Satoshi Tsuneda
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Naohiro Noda
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
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39
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Walling LR, Butler JS. Toxins targeting transfer RNAs: Translation inhibition by bacterial toxin-antitoxin systems. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 10:e1506. [PMID: 30296016 DOI: 10.1002/wrna.1506] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/07/2018] [Accepted: 08/13/2018] [Indexed: 01/09/2023]
Abstract
Prokaryotic toxin-antitoxin (TA) systems are composed of a protein toxin and its cognate antitoxin. These systems are abundant in bacteria and archaea and play an important role in growth regulation. During favorable growth conditions, the antitoxin neutralizes the toxin's activity. However, during conditions of stress or starvation, the antitoxin is inactivated, freeing the toxin to inhibit growth and resulting in dormancy. One mechanism of growth inhibition used by several TA systems results from targeting transfer RNAs (tRNAs), either through preventing aminoacylation, acetylating the primary amino group, or endonucleolytic cleavage. All of these mechanisms inhibit translation and result in growth arrest. Many of these toxins only act on a specific tRNA or a specific subset of tRNAs; however, more work is necessary to understand the specificity determinants of these toxins. For the toxins whose specificity has been characterized, both sequence and structural components of the tRNA appear important for recognition by the toxin. Questions also remain regarding the mechanisms used by dormant bacteria to resume growth after toxin induction. Rescue of stalled ribosomes by transfer-messenger RNAs, removal of acetylated amino groups from tRNAs, or ligation of cleaved RNA fragments have all been implicated as mechanisms for reversing toxin-induced dormancy. However, the mechanisms of resuming growth after induction of the majority of tRNA targeting toxins are not yet understood. This article is categorized under: Translation > Translation Regulation RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition.
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Affiliation(s)
- Lauren R Walling
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York
| | - J Scott Butler
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York.,Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York.,Center for RNA Biology, University of Rochester Medical Center, Rochester, New York
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40
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Lu L, Li J, Moussaoui M, Boix E. Immune Modulation by Human Secreted RNases at the Extracellular Space. Front Immunol 2018; 9:1012. [PMID: 29867984 PMCID: PMC5964141 DOI: 10.3389/fimmu.2018.01012] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/23/2018] [Indexed: 12/23/2022] Open
Abstract
The ribonuclease A superfamily is a vertebrate-specific family of proteins that encompasses eight functional members in humans. The proteins are secreted by diverse innate immune cells, from blood cells to epithelial cells and their levels in our body fluids correlate with infection and inflammation processes. Recent studies ascribe a prominent role to secretory RNases in the extracellular space. Extracellular RNases endowed with immuno-modulatory and antimicrobial properties can participate in a wide variety of host defense tasks, from performing cellular housekeeping to maintaining body fluid sterility. Their expression and secretion are induced in response to a variety of injury stimuli. The secreted proteins can target damaged cells and facilitate their removal from the focus of infection or inflammation. Following tissue damage, RNases can participate in clearing RNA from cellular debris or work as signaling molecules to regulate the host response and contribute to tissue remodeling and repair. We provide here an overall perspective on the current knowledge of human RNases’ biological properties and their role in health and disease. The review also includes a brief description of other vertebrate family members and unrelated extracellular RNases that share common mechanisms of action. A better knowledge of RNase mechanism of actions and an understanding of their physiological roles should facilitate the development of novel therapeutics.
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Affiliation(s)
- Lu Lu
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Jiarui Li
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Mohammed Moussaoui
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Ester Boix
- Department of Biochemistry and Molecular Biology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
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41
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Quorum Sensing Extracellular Death Peptides Enhance the Endoribonucleolytic Activities of Mycobacterium tuberculosis MazF Toxins. mBio 2018; 9:mBio.00685-18. [PMID: 29717013 PMCID: PMC5930309 DOI: 10.1128/mbio.00685-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
mazEF is a toxin-antitoxin module located on chromosomes of most bacteria. MazF toxins are endoribonucleases antagonized by MazE antitoxins. Previously, we characterized several quorum sensing peptides called "extracellular death factors" (EDFs). When secreted from bacterial cultures, EDFs induce interspecies cell death. EDFs also enhance the endoribonucleolytic activity of Escherichia coli MazF. Mycobacterium tuberculosis carries several mazEF modules. Among them, the endoribonucleolytic activities of MazF proteins mt-1, mt-3, and mt-6 were identified. MazF-mt6 and MazF-mt-3 cleave M. tuberculosis rRNAs. Here we report the in vitro effects of EDFs on the endoribonucleolytic activities of M. tuberculosis MazFs. Escherichia coli EDF (EcEDF) and the three Pseudomonas aeruginosa EDFs (PaEDFs) individually enhance the endoribonucleolytic activities of MazF-mt6 and MazF-mt3 and overcome the inhibitory effect of MazE-mt3 or MazE-mt6 on the endoribonucleolytic activities of the respective toxins. We propose that these EDFs can serve as a basis for a novel class of antibiotics against M. tuberculosis. Mycobacterium tuberculosis is one of the leading causes of death from infectious disease. M. tuberculosis is highly drug resistant, and drug delivery to the infected site is very difficult. In previous studies, we showed that extracellular death factors (EDFs) can work as quorum sensing molecules which participate in interspecies bacterial cell death. In this study, we demonstrated the role of different EDFs in the endoribonucleolytic activities of M. tuberculosis MazFs. Escherichia coli EDF (EcEDF) and the three Pseudomonas aeruginosa EDFs (PaEDFs) individually enhance the endoribonucleolytic activities of MazF-mt6 and MazF-mt3. The current report provides a basis for the use of the EDF peptides EcEDF and PaEDF as novel antibiotics against M. tuberculosis.
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Harms A, Brodersen DE, Mitarai N, Gerdes K. Toxins, Targets, and Triggers: An Overview of Toxin-Antitoxin Biology. Mol Cell 2018; 70:768-784. [PMID: 29398446 DOI: 10.1016/j.molcel.2018.01.003] [Citation(s) in RCA: 418] [Impact Index Per Article: 69.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 11/06/2017] [Accepted: 01/02/2018] [Indexed: 12/01/2022]
Abstract
Bacterial toxin-antitoxin (TA) modules are abundant genetic elements that encode a toxin protein capable of inhibiting cell growth and an antitoxin that counteracts the toxin. The majority of toxins are enzymes that interfere with translation or DNA replication, but a wide variety of molecular activities and cellular targets have been described. Antitoxins are proteins or RNAs that often control their cognate toxins through direct interactions and, in conjunction with other signaling elements, through transcriptional and translational regulation of TA module expression. Three major biological functions of TA modules have been discovered, post-segregational killing ("plasmid addiction"), abortive infection (bacteriophage immunity through altruistic suicide), and persister formation (antibiotic tolerance through dormancy). In this review, we summarize the current state of the field and highlight how multiple levels of regulation shape the conditions of toxin activation to achieve the different biological functions of TA modules.
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Affiliation(s)
- Alexander Harms
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Ditlev Egeskov Brodersen
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark; Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Namiko Mitarai
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark; Niels Bohr Institute, Department of Physics, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Kenn Gerdes
- Centre for Bacterial Stress Response and Persistence, Department of Biology, University of Copenhagen, 2200 Copenhagen, Denmark.
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43
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Garcia EC. Contact-dependent interbacterial toxins deliver a message. Curr Opin Microbiol 2017; 42:40-46. [PMID: 29078204 DOI: 10.1016/j.mib.2017.09.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/06/2017] [Accepted: 09/14/2017] [Indexed: 02/04/2023]
Abstract
Both Gram-negative and Gram-positive organisms harbor systems for delivering toxins to neighboring bacteria upon direct cell contact. These systems, typified by type VI secretion (T6S) and contact-dependent growth inhibition (CDI) systems, are defined by their ability to mediate interbacterial competition in vitro, while their biological roles have remained uncertain. Recent research into the mechanisms of toxin delivery and activity, as well as investigation of contact-dependent toxin function during relevant biological processes, has offered insight into how interbacterial competition might work outside of the laboratory. Furthermore, non-competitive roles for contact-dependent toxin delivery systems, including interbacterial signal transduction, have been described. This review suggests that contact-dependent toxin delivery systems that exhibit functions beyond interbacterial competition are probably more common than currently appreciated.
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Affiliation(s)
- Erin C Garcia
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY 40536, United States.
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44
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Deter HS, Jensen RV, Mather WH, Butzin NC. Mechanisms for Differential Protein Production in Toxin-Antitoxin Systems. Toxins (Basel) 2017; 9:E211. [PMID: 28677629 PMCID: PMC5535158 DOI: 10.3390/toxins9070211] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 06/19/2017] [Accepted: 06/23/2017] [Indexed: 02/06/2023] Open
Abstract
Toxin-antitoxin (TA) systems are key regulators of bacterial persistence, a multidrug-tolerant state found in bacterial species that is a major contributing factor to the growing human health crisis of antibiotic resistance. Type II TA systems consist of two proteins, a toxin and an antitoxin; the toxin is neutralized when they form a complex. The ratio of antitoxin to toxin is significantly greater than 1.0 in the susceptible population (non-persister state), but this ratio is expected to become smaller during persistence. Analysis of multiple datasets (RNA-seq, ribosome profiling) and results from translation initiation rate calculators reveal multiple mechanisms that ensure a high antitoxin-to-toxin ratio in the non-persister state. The regulation mechanisms include both translational and transcriptional regulation. We classified E. coli type II TA systems into four distinct classes based on the mechanism of differential protein production between toxin and antitoxin. We find that the most common regulation mechanism is translational regulation. This classification scheme further refines our understanding of one of the fundamental mechanisms underlying bacterial persistence, especially regarding maintenance of the antitoxin-to-toxin ratio.
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Affiliation(s)
- Heather S Deter
- Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0435, USA.
- Center for Soft Matter and Biological Physics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0435, USA.
| | - Roderick V Jensen
- Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0435, USA.
| | | | - Nicholas C Butzin
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57006, USA.
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45
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Miyamoto T, Ota Y, Yokota A, Suyama T, Tsuneda S, Noda N. Characterization of a Deinococcus radiodurans MazF: A UACA-specific RNA endoribonuclease. Microbiologyopen 2017; 6. [PMID: 28675659 PMCID: PMC5635168 DOI: 10.1002/mbo3.501] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 04/20/2017] [Accepted: 05/03/2017] [Indexed: 11/15/2022] Open
Abstract
Microbes are known to withstand environmental stresses by using chromosomal toxin–antitoxin systems. MazEF is one of the most extensively studied toxin–antitoxin systems. In stressful environments, MazF toxins modulate translation by cleaving single‐stranded RNAs in a sequence‐specific fashion. Previously, a chromosomal gene located at DR0417 in Deinococcus radiodurans was predicted to code for a MazF endoribonuclease (MazFDR0417); however, its function remains unclear. In the present study, we characterized the molecular function of MazFDR0417. Analysis of MazFDR0417‐cleaved RNA sites using modified massively parallel sequencing revealed a unique 4‐nt motif, UACA, as a potential cleavage pattern. The activity of MazFDR0417 was also assessed in a real‐time fluorometric assay, which revealed that MazFDR0417 strictly recognizes the unique tetrad UACA. This sequence specificity may allow D. radiodurans to alter its translation profile and survive under stressful conditions.
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Affiliation(s)
- Tatsuki Miyamoto
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Yuri Ota
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Akiko Yokota
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Tetsushi Suyama
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Satoshi Tsuneda
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan
| | - Naohiro Noda
- Department of Life Science and Medical Bioscience, Waseda University, Tokyo, Japan.,Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
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46
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Harris ME, York DM, Piccirilli JA, Anderson VE. Kinetic Isotope Effect Analysis of RNA 2′- O -Transphosphorylation. Methods Enzymol 2017; 596:433-457. [DOI: 10.1016/bs.mie.2017.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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