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Gu Q, Zhu X, Yu Y, Jiang T, Pan Z, Ma J, Yao H. Type II and IV toxin-antitoxin systems coordinately stabilize the integrative and conjugative element of the ICESa2603 family conferring multiple drug resistance in Streptococcus suis. PLoS Pathog 2024; 20:e1012169. [PMID: 38640137 PMCID: PMC11062541 DOI: 10.1371/journal.ppat.1012169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 05/01/2024] [Accepted: 04/02/2024] [Indexed: 04/21/2024] Open
Abstract
Integrative and conjugative elements (ICEs) play a vital role in bacterial evolution by carrying essential genes that confer adaptive functions to the host. Despite their importance, the mechanism underlying the stable inheritance of ICEs, which is necessary for the acquisition of new traits in bacteria, remains poorly understood. Here, we identified SezAT, a type II toxin-antitoxin (TA) system, and AbiE, a type IV TA system encoded within the ICESsuHN105, coordinately promote ICE stabilization and mediate multidrug resistance in Streptococcus suis. Deletion of SezAT or AbiE did not affect the strain's antibiotic susceptibility, but their duple deletion increased susceptibility, mainly mediated by the antitoxins SezA and AbiEi. Further studies have revealed that SezA and AbiEi affect the genetic stability of ICESsuHN105 by moderating the excision and extrachromosomal copy number, consequently affecting the antibiotic resistance conferred by ICE. The DNA-binding proteins AbiEi and SezA, which bind palindromic sequences in the promoter, coordinately modulate ICE excision and extracellular copy number by binding to sequences in the origin-of-transfer (oriT) and the attL sites, respectively. Furthermore, AbiEi negatively regulates the transcription of SezAT by binding directly to its promoter, optimizing the coordinate network of SezAT and AbiE in maintaining ICESsuHN105 stability. Importantly, SezAT and AbiE are widespread and conserved in ICEs harbouring diverse drug-resistance genes, and their coordinated effects in promoting ICE stability and mediating drug resistance may be broadly applicable to other ICEs. Altogether, our study uncovers the TA system's role in maintaining the genetic stability of ICE and offers potential targets for overcoming the dissemination and evolution of drug resistance.
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Affiliation(s)
- Qibing Gu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Xiayu Zhu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Yong Yu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Tao Jiang
- Department of Stomatology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Zihao Pan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Jiale Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
| | - Huochun Yao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, China
- OIE Reference Lab for Swine Streptococcosis, Nanjing, China
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Karimaei S, Aghamir SMK, Pourmand MR. Comparative analysis of genes expression involved in type II toxin-antitoxin system in Staphylococcus aureus following persister cell formation. Mol Biol Rep 2024; 51:324. [PMID: 38393536 DOI: 10.1007/s11033-023-09179-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 12/18/2023] [Indexed: 02/25/2024]
Abstract
BACKGROUND The formation of persister cells is the main reason for persistent infections. They are associated with antibiotic treatment failure and subsequently chronic infection. The study aimed to assess the expression of type II toxin/antitoxin (TA) system genes in persister cells of Staphylococcus aureus in the presence of the following antibiotics vancomycin, ciprofloxacin, and gentamicin in exponential and stationary phases. METHODS AND RESULTS The colony count was used to evaluate the effect of different types of antibiotics on S. aureus persister cell formation during exponential and stationary phases. Moreover, the expression level of TA systems and clpP genes in the persister population in exponential and stationary phases were measured by quantitative reverse transcriptase real-time PCR (qRT-PCR). The results of the study showed the presence of persister phenotype of S. aureus strains in the attendance of bactericidal antibiotics in comparison to the control group during the exponential and stationary phases. Moreover, qRT-PCR resulted in the fact that the role of TA systems involved in the persister cell formation depends on the bacterial growth phase and the type of strain and antibiotic. CONCLUSIONS In total, the present study provides some data on the persister cell formation and the possible role of TA system genes in this process.
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Affiliation(s)
- Samira Karimaei
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Mohammad Reza Pourmand
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
- Department of Pathobiology, School of Public Health and Biotechnology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
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3
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Ardissone S, Greub G. The Chlamydia-related Waddlia chondrophila encodes functional type II toxin-antitoxin systems. Appl Environ Microbiol 2024; 90:e0068123. [PMID: 38214519 PMCID: PMC10880633 DOI: 10.1128/aem.00681-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 11/13/2023] [Indexed: 01/13/2024] Open
Abstract
Bacterial toxin-antitoxin (TA) systems are widespread in chromosomes and plasmids of free-living microorganisms, but only a few have been identified in obligate intracellular species. We found seven putative type II TA modules in Waddlia chondrophila, a Chlamydia-related species that is able to infect a very broad series of eukaryotic hosts, ranging from protists to mammalian cells. The RNA levels of Waddlia TA systems are significantly upregulated by iron starvation and novobiocin, but they are not affected by antibiotics such as β-lactams and glycopeptides, which suggests different mechanisms underlying stress responses. Five of the identified TA modules, including HigBA1 and MazEF1, encoded on the Waddlia cryptic plasmid, proved to be functional when expressed in a heterologous host. TA systems have been associated with the maintenance of mobile genetic elements, bacterial defense against bacteriophages, and persistence upon exposure to adverse conditions. As their RNA levels are upregulated upon exposure to adverse conditions, Waddlia TA modules may be involved in survival to stress. Moreover, as Waddlia can infect a wide range of hosts including free-living amoebae, TA modules could also represent an innate immunity system to fight against bacteriophages and other microorganisms with which Waddlia has to share its replicative niche.IMPORTANCEThe response to adverse conditions, such as exposure to antibiotics, nutrient starvation and competition with other microorganisms, is essential for the survival of a bacterial population. TA systems are modules composed of two elements, a toxic protein and an antitoxin (protein or RNA) that counteracts the toxin. Although many aspects of TA biological functions still await to be elucidated, TAs have often been implicated in bacterial response to stress, including the response to nutrient starvation, antibiotic treatment and bacteriophage infection. TAs are ubiquitous in free-living bacteria but rare in obligate intracellular species such as chlamydiae. We identified functional TA systems in Waddlia chondrophila, a chlamydial species with a strikingly broad host range compared to other chlamydiae. Our work contributes to understand how obligate intracellular bacteria react to adverse conditions that might arise from competition with other viruses/bacteria for the same replicative niche and would threaten their ability to replicate.
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Affiliation(s)
- Silvia Ardissone
- Institute of Microbiology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
| | - Gilbert Greub
- Institute of Microbiology, Lausanne University Hospital and Lausanne University, Lausanne, Switzerland
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Shafipour M, Mohammadzadeh A, Ghaemi EA, Mahmoodi P. PCR Development for Analysis of Some Type II Toxin-Antitoxin Systems, relJK, mazEF3, and vapBC3 Genes, in Mycobacterium tuberculosis and Mycobacterium bovis. Curr Microbiol 2024; 81:90. [PMID: 38311651 DOI: 10.1007/s00284-023-03599-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 12/22/2023] [Indexed: 02/06/2024]
Abstract
Toxin-Antitoxin (TA) systems are some small genetic modules in bacteria that play significant roles in resistance and tolerance development to antibiotics. Whole genome sequencing (WGS) is an effective method to analyze TA systems in pathogenic Mycobacteria. However, this study aimed to use a simple and inexpensive PCR-Sequencing approach to investigate the type II TA system. Using data from the WGS of Mycobacterium tuberculosis (M. tuberculosis) strain H37Rv and Mycobacterium bovis (M. bovis) strain BCG, primers specific to the relJK, mazEF3, and vapBC3 gene families were designed by Primer3 software. Following that, a total of 90 isolates were examined using the newly developed PCR assay, consisting of 64 M. tuberculosis and 26 M. bovis isolates, encompassing both 45 rifampin-sensitive and 45 rifampin-resistant strains. Finally, 28 isolates (including 14 rifampin-resistant isolates) were sent for sequencing, and their sequences were aligned and compared to the mentioned reference sequences. The amplicons size of mazEF3, relJK, and vapBC3 genes were 825, 875, and 934 bp, respectively. Furthermore, all tested isolates showed the specific amplicons for these TA families. To evaluate the specificity of the primers, PCR was performed on S. aureus and E.coli isolates. None of the examined samples had the desired amplicons. Therefore, the primers had acceptable specificity. The results indicated that the developed PCR-Sequencing approach can be used to effectively investigate certain types of TA systems. Considering high costs of WGS and difficulty in interpreting its results, such a simple and inexpensive method is beneficial in the evaluation of TA systems in Mycobacteria.
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Affiliation(s)
- Maryam Shafipour
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, Iran
| | - Abdolmajid Mohammadzadeh
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, Iran.
| | - Ezzat Allah Ghaemi
- Infectious Diseases Research Center, Golestan University of Medical Sciences, Gorgan, Iran
| | - Pezhman Mahmoodi
- Department of Pathobiology, Faculty of Veterinary Medicine, Bu-Ali Sina University, Hamedan, Iran
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Bonabal S, Darfeuille F. Preventing toxicity in toxin-antitoxin systems: An overview of regulatory mechanisms. Biochimie 2024; 217:95-105. [PMID: 37473832 DOI: 10.1016/j.biochi.2023.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/22/2023]
Abstract
Toxin-antitoxin systems (TAs) are generally two-component genetic modules present in almost every prokaryotic genome. The production of the free and active toxin is able to disrupt key cellular processes leading to the growth inhibition or death of its host organism in absence of its cognate antitoxin. The functions attributed to TAs rely on this lethal phenotype ranging from mobile genetic elements stabilization to phage defense. Their abundance in prokaryotic genomes as well as their lethal potential make them attractive targets for new antibacterial strategies. The hijacking of TAs requires a deep understanding of their regulation to be able to design such approach. In this review, we summarize the accumulated knowledge on how bacteria cope with these toxic genes in their genome. The characterized TAs can be grouped based on the way they prevent toxicity. Some systems rely on a tight control of the expression to prevent the production of the toxin while others control the activity of the toxin at the post-translational level.
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Affiliation(s)
- Simon Bonabal
- University of Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, F-33000, Bordeaux, France
| | - Fabien Darfeuille
- University of Bordeaux, INSERM U1212, CNRS UMR 5320, ARNA Laboratory, F-33000, Bordeaux, France.
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Singh A, Lankapalli AK, Mendem SK, Semmler T, Ahmed N. Unraveling the evolutionary dynamics of toxin-antitoxin systems in diverse genetic lineages of Escherichia coli including the high-risk clonal complexes. mBio 2024; 15:e0302323. [PMID: 38117088 PMCID: PMC10790755 DOI: 10.1128/mbio.03023-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 12/21/2023] Open
Abstract
IMPORTANCE Large-scale genomic studies of E. coli provide an invaluable opportunity to understand how genomic fine-tuning contributes to the transition of bacterial lifestyle from being commensals to mutualists or pathogens. Within this context, through machine learning-based studies, it appears that TA systems play an important role in the classification of high-risk clonal lineages and could be attributed to their epidemiological success. Due to these profound indications and assumptions, we attempted to provide unique insights into the ordered world of TA systems at the population level by investigating the diversity and evolutionary patterns of TA genes across 19 different STs of E. coli. Further in-depth analysis of ST-specific TA structures and associated genetic coordinates holds the potential to elucidate the functional implications of TA systems in bacterial cell survival and persistence, by and large.
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Affiliation(s)
- Anuradha Singh
- Pathogen Biology Laboratory, Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana State, India
| | - Aditya Kumar Lankapalli
- Department of Biology and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, Oxford, United Kingdom
| | - Suresh Kumar Mendem
- Pathogen Biology Laboratory, Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana State, India
| | | | - Niyaz Ahmed
- Pathogen Biology Laboratory, Department of Biotechnology and Bioinformatics, University of Hyderabad, Hyderabad, Telangana State, India
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Richard E, Darracq B, Littner E, Vit C, Whiteway C, Bos J, Fournes F, Garriss G, Conte V, Lapaillerie D, Parissi V, Rousset F, Skovgaard O, Bikard D, Rocha EPC, Mazel D, Loot C. Cassette recombination dynamics within chromosomal integrons are regulated by toxin-antitoxin systems. Sci Adv 2024; 10:eadj3498. [PMID: 38215203 DOI: 10.1126/sciadv.adj3498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 12/14/2023] [Indexed: 01/14/2024]
Abstract
Integrons are adaptive bacterial devices that rearrange promoter-less gene cassettes into variable ordered arrays under stress conditions, thereby sampling combinatorial phenotypic diversity. Chromosomal integrons often carry hundreds of silent gene cassettes, with integrase-mediated recombination leading to rampant DNA excision and integration, posing a potential threat to genome integrity. How this activity is regulated and controlled, particularly through selective pressures, to maintain such large cassette arrays is unknown. Here, we show a key role of promoter-containing toxin-antitoxin (TA) cassettes as systems that kill the cell when the overall cassette excision rate is too high. These results highlight the importance of TA cassettes regulating the cassette recombination dynamics and provide insight into the evolution and success of integrons in bacterial genomes.
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Affiliation(s)
- Egill Richard
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
- Sorbonne Université, ED515, F-75005 Paris, France
| | - Baptiste Darracq
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
- Sorbonne Université, ED515, F-75005 Paris, France
| | - Eloi Littner
- Sorbonne Université, ED515, F-75005 Paris, France
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, 75015 Paris, France
- DGA CBRN Defence, 91710 Vert-le-Petit, France
| | - Claire Vit
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
- Sorbonne Université, ED515, F-75005 Paris, France
| | - Clémence Whiteway
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
| | - Julia Bos
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
| | - Florian Fournes
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
| | - Geneviève Garriss
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
| | - Valentin Conte
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
| | - Delphine Lapaillerie
- University of Bordeaux, Fundamental Microbiology and Pathogenicity Laboratory, CNRS, UMR 5234, SFR TransBioMed, Bordeaux, France
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), France
| | - Vincent Parissi
- University of Bordeaux, Fundamental Microbiology and Pathogenicity Laboratory, CNRS, UMR 5234, SFR TransBioMed, Bordeaux, France
- Viral DNA Integration and Chromatin Dynamics Network (DyNAVir), France
| | - François Rousset
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Synthetic Biology, 75015 Paris, France
| | - Ole Skovgaard
- Department of Science, Systems and Models, Roskilde University, Roskilde DK-4000, Denmark
| | - David Bikard
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Synthetic Biology, 75015 Paris, France
| | - Eduardo P C Rocha
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Microbial Evolutionary Genomics, 75015 Paris, France
| | - Didier Mazel
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
| | - Céline Loot
- Institut Pasteur, Université Paris Cité, CNRS UMR3525, Unité Plasticité du Génome Bactérien, 75015 Paris, France
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Guan J, Chen Y, Goh YX, Wang M, Tai C, Deng Z, Song J, Ou HY. TADB 3.0: an updated database of bacterial toxin-antitoxin loci and associated mobile genetic elements. Nucleic Acids Res 2024; 52:D784-D790. [PMID: 37897352 PMCID: PMC10767807 DOI: 10.1093/nar/gkad962] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/11/2023] [Accepted: 10/14/2023] [Indexed: 10/30/2023] Open
Abstract
TADB 3.0 (https://bioinfo-mml.sjtu.edu.cn/TADB3/) is an updated database that provides comprehensive information on bacterial types I to VIII toxin-antitoxin (TA) loci. Compared with the previous version, three major improvements are introduced: First, with the aid of text mining and manual curation, it records the details of 536 TA loci with experimental support, including 102, 403, 8, 14, 1, 1, 3 and 4 TA loci of types I to VIII, respectively; Second, by leveraging the upgraded TA prediction tool TAfinder 2.0 with a stringent strategy, TADB 3.0 collects 211 697 putative types I to VIII TA loci predicted in 34 789 completely sequenced prokaryotic genomes, providing researchers with a large-scale dataset for further follow-up analysis and characterization; Third, based on their genomic locations, relationships of 69 019 TA loci and 60 898 mobile genetic elements (MGEs) are visualized by interactive networks accessible through the user-friendly web page. With the recent updates, TADB 3.0 may provide improved in silico support for comprehending the biological roles of TA pairs in prokaryotes and their functional associations with MGEs.
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Affiliation(s)
- Jiahao Guan
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yongkui Chen
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ying-Xian Goh
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Meng Wang
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Cui Tai
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zixin Deng
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jiangning Song
- Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia
- Monash Data Futures Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Hong-Yu Ou
- State Key Laboratory of Microbial Metabolism, Joint International Laboratory on Metabolic & Developmental Sciences, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Yan Y, Zheng J, Zhang X, Yin Y. dbAPIS: a database of anti-prokaryotic immune system genes. Nucleic Acids Res 2024; 52:D419-D425. [PMID: 37889074 PMCID: PMC10767833 DOI: 10.1093/nar/gkad932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 09/20/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
Anti-prokaryotic immune system (APIS) proteins, typically encoded by phages, prophages, and plasmids, inhibit prokaryotic immune systems (e.g. restriction modification, toxin-antitoxin, CRISPR-Cas). A growing number of APIS genes have been characterized and dispersed in the literature. Here we developed dbAPIS (https://bcb.unl.edu/dbAPIS), as the first literature curated data repository for experimentally verified APIS genes and their associated protein families. The key features of dbAPIS include: (i) experimentally verified APIS genes with their protein sequences, functional annotation, PDB or AlphaFold predicted structures, genomic context, sequence and structural homologs from different microbiome/virome databases; (ii) classification of APIS proteins into sequence-based families and construction of hidden Markov models (HMMs); (iii) user-friendly web interface for data browsing by the inhibited immune system types or by the hosts, and functions for searching and batch downloading of pre-computed data; (iv) Inclusion of all types of APIS proteins (except for anti-CRISPRs) that inhibit a variety of prokaryotic defense systems (e.g. RM, TA, CBASS, Thoeris, Gabija). The current release of dbAPIS contains 41 verified APIS proteins and ∼4400 sequence homologs of 92 families and 38 clans. dbAPIS will facilitate the discovery of novel anti-defense genes and genomic islands in phages, by providing a user-friendly data repository and a web resource for an easy homology search against known APIS proteins.
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Affiliation(s)
- Yuchen Yan
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | | | - Xinpeng Zhang
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
| | - Yanbin Yin
- Nebraska Food for Health Center, Department of Food Science and Technology, University of Nebraska - Lincoln, Lincoln, NE 68588, USA
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10
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Guler P, Bendori SO, Borenstein T, Aframian N, Kessel A, Eldar A. Arbitrium communication controls phage lysogeny through non-lethal modulation of a host toxin-antitoxin defence system. Nat Microbiol 2024; 9:150-160. [PMID: 38177304 DOI: 10.1038/s41564-023-01551-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 11/07/2023] [Indexed: 01/06/2024]
Abstract
Temperate Bacillus phages often utilize arbitrium communication to control lysis/lysogeny decisions, but the mechanisms by which this control is exerted remains largely unknown. Here we find that the arbitrium system of Bacillus subtilis phage ϕ3T modulates the host-encoded MazEF toxin-antitoxin system to this aim. Upon infection, the MazF ribonuclease is activated by three phage genes. At low arbitrium signal concentrations, MazF is inactivated by two phage-encoded MazE homologues: the arbitrium-controlled AimX and the later-expressed YosL proteins. At high signal, MazF remains active, promoting lysogeny without harming the bacterial host. MazF cleavage sites are enriched on transcripts of phage lytic genes but absent from the phage repressor in ϕ3T and other Spβ-like phages. Combined with low activation levels of MazF during infections, this pattern explains the phage-specific effect. Our results show how a bacterial toxin-antitoxin system has been co-opted by a phage to control lysis/lysogeny decisions without compromising host viability.
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Affiliation(s)
- Polina Guler
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Shira Omer Bendori
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Tom Borenstein
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Nitzan Aframian
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Amit Kessel
- Department of Biochemistry and Molecular Biology, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
| | - Avigdor Eldar
- Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
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Wang X, Kan Y, Bai K, Xu X, Chen X, Yu C, Shi J, Jiang N, Li J, Luo L. A novel double-ribonuclease toxin-antitoxin system linked to the stress response and survival of Acidovorax citrulli. Microbiol Spectr 2023; 11:e0216923. [PMID: 37819152 PMCID: PMC10714953 DOI: 10.1128/spectrum.02169-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 08/30/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Bacterial fruit blotch (BFB), which is caused by the seed-borne bacterium Acidovorax citrulli, is a devastating disease affecting cucurbit crops throughout the world. Although seed fermentation and treatment with disinfectants can provide effective management of BFB, they cannot completely guarantee pathogen-free seedstock, which suggests that A. citrulli is a highly stress-resistant pathogen. Toxin-antitoxin (TA) systems are common among a diverse range of bacteria and have been reported to play a role in bacterial stress response. However, there is currently much debate about the relationship between TA systems and stress response in bacteria. The current study characterized a novel TA system (Aave_1720-Aave_1719) from A. citrulli that affects both biofilm formation and survival in response to sodium hypochlorite stress. The mechanism of neutralization differed from typical TA systems as two separate mechanisms were associated with the antitoxin, which exhibited characteristics of both type II and type V TA systems. The Aave_1720-Aave_1719 system described here also constitutes the first known report of a double-ribonuclease TA system in bacteria, which expands our understanding of the range of regulatory mechanisms utilized by bacterial TA systems, providing new insight into the survival of A. citrulli in response to stress.
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Affiliation(s)
- Xudong Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Yumin Kan
- Department of Biochemistry and Cell Biology, State University of New York, Stony Brook, New York, USA
| | - Kaihong Bai
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Xiaoli Xu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Xing Chen
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Chengxuan Yu
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Jia Shi
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Na Jiang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Jianqiang Li
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
| | - Laixin Luo
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
- Key Laboratory of Surveillance and Management for Plant Quarantine Pests, Ministry of Agriculture and Rural Affairs, Beijing, China
- Beijing Key Laboratory of Seed Disease Testing and Control, Beijing, China
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12
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Khan S, Ahmad F, Ansari MI, Ashfaque M, Islam MH, Khubaib M. Toxin-Antitoxin system of Mycobacterium tuberculosis: Roles beyond stress sensor and growth regulator. Tuberculosis (Edinb) 2023; 143:102395. [PMID: 37722233 DOI: 10.1016/j.tube.2023.102395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/15/2023] [Accepted: 08/10/2023] [Indexed: 09/20/2023]
Abstract
The advent of effective drug regimen and BCG vaccine has significantly decreased the rate of morbidity and mortality of TB. However, lengthy treatment and slower recovery rate, as well as reactivation of the disease with the emergence of multi-drug, extensively-drug, and totally-drug resistance strains, pose a serious concern. The complexities associated are due to the highly evolved and complex nature of the bacterium itself. One of the unique features of Mycobacterium tuberculosis [M.tb] is that it has undergone reductive evolution while maintaining and amplified a few gene families. One of the critical gene family involved in the virulence and pathogenesis is the Toxin-Antitoxin system. These families are believed to harbor virulence signature and are strongly associated with various stress adaptations and pathogenesis. The M.tb TA systems are linked with growth regulation machinery during various environmental stresses. The genes of TA systems are differentially expressed in the host during an active infection, oxidative stress, low pH stress, and starvation, which essentially indicate their role beyond growth regulators. Here in this review, we have discussed different roles of TA gene families in various stresses and their prospective role at the host-pathogen interface, which could be exploited to understand the M.tb associated pathomechanisms better and further designing the new strategies against the pathogen.
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Affiliation(s)
- Saima Khan
- Department of Biosciences, Integral University, Lucknow, India
| | - Firoz Ahmad
- Department of Biosciences, Integral University, Lucknow, India
| | | | | | | | - Mohd Khubaib
- Department of Biosciences, Integral University, Lucknow, India.
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13
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Bærentsen RL, Nielsen SV, Skjerning RB, Lyngsø J, Bisiak F, Pedersen JS, Gerdes K, Sørensen MA, Brodersen DE. Structural basis for kinase inhibition in the tripartite E. coli HipBST toxin-antitoxin system. eLife 2023; 12:RP90400. [PMID: 37929938 PMCID: PMC10627512 DOI: 10.7554/elife.90400] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023] Open
Abstract
Many bacteria encode multiple toxin-antitoxin (TA) systems targeting separate, but closely related, cellular functions. The toxin of the Escherichia coli hipBA system, HipA, is a kinase that inhibits translation via phosphorylation of glutamyl-tRNA synthetase. Enteropathogenic E. coli O127:H6 encodes the hipBA-like, tripartite TA system; hipBST, in which the HipT toxin specifically targets the tryptophanyl-tRNA synthetase, TrpS. Notably, in the tripartite system, the function as antitoxin has been taken over by the third protein, HipS, but the molecular details of how activity of HipT is inhibited remain poorly understood. Here, we show that HipBST is structurally different from E. coli HipBA and that the unique HipS protein, which is homologous to the N-terminal subdomain of HipA, inhibits the kinase through insertion of a conserved Trp residue into the active site. We also show how auto-phosphorylation at two conserved sites in the kinase toxin serve different roles and affect the ability of HipS to neutralize HipT. Finally, solution structural studies show how phosphorylation affects overall TA complex flexibility.
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Affiliation(s)
- René L Bærentsen
- Department of Molecular Biology and Genetics, Aarhus UniversityAarhusDenmark
| | - Stine V Nielsen
- Department of Biology, University of CopenhagenCopenhagenDenmark
| | | | - Jeppe Lyngsø
- Department of Chemistry and Interdisciplinary Nanoscience Centre (iNANO)AarhusDenmark
| | - Francesco Bisiak
- Department of Molecular Biology and Genetics, Aarhus UniversityAarhusDenmark
| | - Jan Skov Pedersen
- Department of Chemistry and Interdisciplinary Nanoscience Centre (iNANO)AarhusDenmark
| | | | | | - Ditlev E Brodersen
- Department of Molecular Biology and Genetics, Aarhus UniversityAarhusDenmark
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14
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Lin JD, Stogios PJ, Abe KT, Wang A, MacPherson J, Skarina T, Gingras AC, Savchenko A, Ensminger AW. Functional diversification despite structural congruence in the HipBST toxin-antitoxin system of Legionella pneumophila. mBio 2023; 14:e0151023. [PMID: 37819088 PMCID: PMC10653801 DOI: 10.1128/mbio.01510-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/29/2023] [Indexed: 10/13/2023] Open
Abstract
IMPORTANCE Toxin-antitoxin (TA) systems are parasitic genetic elements found in almost all bacterial genomes. They are exchanged horizontally between cells and are typically poorly conserved across closely related strains and species. Here, we report the characterization of a tripartite TA system in the bacterial pathogen Legionella pneumophila that is highly conserved across Legionella species genomes. This system (denoted HipBSTLp) is a distant homolog of the recently discovered split-HipA system in Escherichia coli (HipBSTEc). We present bioinformatic, molecular, and structural analyses of the divergence between these two systems and the functionality of this newly described TA system family. Furthermore, we provide evidence to refute previous claims that the toxin in this system (HipTLp) possesses bifunctionality as an L. pneumophila virulence protein. Overall, this work expands our understanding of the split-HipA system architecture and illustrates the potential for undiscovered biology in these abundant genetic elements.
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Affiliation(s)
- Jordan D. Lin
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Peter J. Stogios
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Kento T. Abe
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Ontario, Canada
| | - Avril Wang
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - John MacPherson
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Tatiana Skarina
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health, Toronto, Ontario, Canada
| | - Alexei Savchenko
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Center for Structural Genomics of Infectious Diseases (CSGID), University of Calgary, Calgary, Alberta, Canada
| | - Alexander W. Ensminger
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
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Valadbeigi H, Sadeghifard N, Kaviar VH, Haddadi MH, Ghafourian S, Maleki A. Effect of ZnO nanoparticles on biofilm formation and gene expression of the toxin-antitoxin system in clinical isolates of Pseudomonas aeruginosa. Ann Clin Microbiol Antimicrob 2023; 22:89. [PMID: 37798613 PMCID: PMC10557154 DOI: 10.1186/s12941-023-00639-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 09/25/2023] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND Biofilm formation by Pseudomonas aeruginosa (P. aeruginosa) is known to be characteristic of this organism. This bacterium is considered one of the most life-threatening bacteria and has been identified as a priority pathogen for research by WHO. Biofilm-producing P. aeruginosa is a concern in many parts of the world due to antibiotic resistance. Alginate also plays an important role in the biofilm formation of P. aeruginosa as well as the emergence of antibiotic resistance in biofilms. In addition, the systems of toxin-antitoxin( TA) play an important role in biofilm formation. Metal nanoparticle(NP) such as zinc oxide (ZnO) also have extensive biological properties, especially anti-biofilm properties. Therefore, this study was conducted in relation to the importance of zinc oxide nanoparticles (ZnO NPs) in biofilm formation and also the correlation of gene expression of TA systems in clinical isolates of P. aeruginosa. METHODS A total of 52 P. aeruginosa isolates were collected from burns (n = 15), UTI (n = 31), and trachea (n = 6) in hospitals in Ilam between May 2020 and October 2020. Biofilm formation was assessed using a microtiter plate assay. MIC and sub-MIC concentrations of ZnO NPs (10-30 nm with purity greater than 99.8%) in P. aeruginosa were determined. Subsequently, biofilm formation was investigated using sub-MIC concentrations of ZnO NPs. Finally, total RNA was extracted and RT- qPCR was used to determine the expression levels of genes of mazEF, mqsRA, and higBA of TA systems. RESULTS Six isolates of P. aeruginosa were found to form strong biofilms. The results showed that ZnO NPs were able to inhibit biofilm formation. In our experiments, we found that the sub-MIC concentration of ZnO NPs increased the gene expression of antitoxins mazE and mqsA and toxin higB of TA systems treated with ZnO NPs. CONCLUSIONS In the present study, ZnO NPs were shown to effectively inhibit biofilm formation in P. aeruginosa. Our results support the relationship between TA systems and ZnO NPs in biofilm formation in P. aeruginosa. Importantly, the expression of antitoxins mazE and mqsA was high after treatment with ZnO NPs, but not that of antitoxin higA.
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Affiliation(s)
- Hassan Valadbeigi
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.
| | - Nourkhoda Sadeghifard
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Vahab Hassan Kaviar
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | | | - Sobhan Ghafourian
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
- Department of Microbiology, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Abbas Maleki
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
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16
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Chen Z, Yao J, Zhang P, Wang P, Ni S, Liu T, Zhao Y, Tang K, Sun Y, Qian Q, Wang X. Minimized antibiotic-free plasmid vector for gene therapy utilizing a new toxin-antitoxin system. Metab Eng 2023; 79:86-96. [PMID: 37451534 DOI: 10.1016/j.ymben.2023.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 06/28/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
Approaches to improve plasmid-mediated transgene expression are needed for gene therapy and genetic immunization applications. The backbone sequences needed for the production of plasmids in bacterial hosts and the use of antibiotic resistance genes as selection markers represent biological safety risks. Here, we report the development of an antibiotic-free expression plasmid vector with a minimized backbone utilizing a new toxin-antitoxin (TA) system. The Rs_0636/Rs_0637 TA pair was derived from the coral-associated bacterium Roseivirga sp. The toxin gene is integrated into the chromosome of Escherichia coli host cells, and a recombinant mammalian expression plasmid is constructed by replacing the antibiotic resistance gene with the antitoxin gene Rs_0637 (here named Tiniplasmid). The Tiniplasmid system affords high selection efficiency (∼80%) for target gene insertion into the plasmid and has high plasmid stability in E. coli (at least 9 days) in antibiotic-free conditions. Furthermore, with the aim of reducing the size of the backbone sequence, we found that the antitoxin gene can be reduced to 153 bp without a significant reduction in selection efficiency. To develop its applications in gene therapy and DNA vaccines, the biosafety and efficiency of the Tiniplasmid-based eukaryotic gene delivery and expression were further evaluated in CHO-K1 cells. The results showed that Rs_0636/Rs_0637 has no cell toxicity and that the Tiniplasmid vector has a higher gene expression efficiency than the commercial vectors pCpGfree and pSTD in the eukaryotic cells. Altogether, the results demonstrate the potential of the Rs_0636/Rs_0637-based antibiotic-free plasmid vector for the development and production of safe and efficacious DNA vaccines.
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Affiliation(s)
- Zhe Chen
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jianyun Yao
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China.
| | - Pingjing Zhang
- Maxirna (Shanghai) Pharmaceutical Co., Ltd., China; Shanghai Cell Therapy Group Co., Ltd, China
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China
| | - Songwei Ni
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Tao Liu
- Maxirna (Shanghai) Pharmaceutical Co., Ltd., China; Shanghai Cell Therapy Group Co., Ltd, China
| | - Yi Zhao
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Kaihao Tang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China
| | - Yan Sun
- Shanghai University Mengchao Cancer Hospital, China
| | - Qijun Qian
- Maxirna (Shanghai) Pharmaceutical Co., Ltd., China; Shanghai Cell Therapy Group Co., Ltd, China; Shanghai University Mengchao Cancer Hospital, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), No. 1119, Haibin Road, Nansha District, Guangzhou, 511458, China.
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Latifi F, Hashemi A, Kalani BS, Pakzad I, Hematian A. abkBA toxin-antitoxin system may act as antipersister modules in Acinetobacter baumannii clinical isolates. Future Microbiol 2023; 18:707-714. [PMID: 37552216 DOI: 10.2217/fmb-2022-0271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/09/2023] Open
Abstract
Aim: Persistence cells comprise a subpopulation of bacteria that is resistant to treatment. In this study, the role of the toxin-antitoxin (TA) system in the formation of persistence cells of Acinetobacter baumannii isolates was investigated. Methods: After confirming all isolates, TA systems abkBA, mqsRA and higBA were identified. Persister cells were confirmed using the standard method. Real-time PCR was used to compare the expression of TA systems in isolates in persistence and normal states. Results: The abkAB system was present in all isolates; 4% of isolates formed persister cells. The expression level of the abkB gene in persistent isolates showed a sevenfold increase compared with nonpersistent isolates. Conclusion: The abkBA system is proposed as an antipersistence target in A. baumannii isolates.
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Affiliation(s)
- Fatemeh Latifi
- Department of Medical Microbiology, Faculty of Medicine, Ilam University of Medical Science, Ilam, Iran
| | - Ali Hashemi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Behrooz S Kalani
- Department of Medical Microbiology, Faculty of Medicine, Ilam University of Medical Science, Ilam, Iran
| | - Iraj Pakzad
- Department of Medical Microbiology, Faculty of Medicine, Ilam University of Medical Science, Ilam, Iran
| | - Ali Hematian
- Department of Medical Microbiology, Faculty of Medicine, Ilam University of Medical Science, Ilam, Iran
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18
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Song Y, Tang H, Bao R. Comparative analysis of five type II TA systems identified in Pseudomonas aeruginosa reveals their contributions to persistence and intracellular survival. Front Cell Infect Microbiol 2023; 13:1127786. [PMID: 36844395 PMCID: PMC9948252 DOI: 10.3389/fcimb.2023.1127786] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 02/01/2023] [Indexed: 02/11/2023] Open
Abstract
Background Pseudomonas aeruginosa is a grave nosocomial pathogen that persistently inhabits the lungs of patients with cystic fibrosis (CF) and causes various chronic infections. The bacterial toxin-antitoxin (TA) system is associated with latent and long-term infections, but the underlying mechanisms remain to be fully characterized. Methods We here investigated the diversity and function of five genomic type II TA systems widely distributed among P. aeruginosa clinical isolates. We also examined the distinct structural features of the toxin protein from different TA systems and characterized their contributions to persistence, invasion ability, and intracellular infection caused by P. aeruginosa. Results ParDE, PA1030/PA1029, and HigBA could modulate persister cell formation under treatment with specific antibiotics. Furthermore, cell-based transcriptional and invasion assays revealed that PA1030/PA1029 and HigBA TA systems were critical for intracellular survival. Discussion Our results highlight the prevalence and diverse roles of type II TA systems in P. aeruginosa and evaluate the possibility of using PA1030/PA1029 and HigBA TA pairs as targets for novel antibiotic treatments.
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Affiliation(s)
- Yingjie Song
- College of Life Science, Sichuan Normal University, Chengdu, China
| | - Hong Tang
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Rui Bao, ; Hong Tang,
| | - Rui Bao
- Division of Infectious Diseases, State Key Laboratory of Biotherapy and Center of Infectious Diseases, West China Hospital, Sichuan University, Chengdu, China
- *Correspondence: Rui Bao, ; Hong Tang,
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Cai T, Zhao QH, Xiang WL, Zhu L, Rao Y, Tang J. HigBA toxin-antitoxin system of Weissella cibaria is involved in response to the bile salt stress. J Sci Food Agric 2022; 102:6749-6756. [PMID: 35633128 DOI: 10.1002/jsfa.12042] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 05/25/2022] [Accepted: 05/28/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Toxin-antitoxin (TA) systems are prevalent adaptive genetic elements in bacterial genomes, which can respond to environmental stress. While, few studies have addressed TA systems in probiotics and their roles in the adaptation to gastrointestinal transit (GIT) environments. RESULTS The Weissella cibaria 018 could survive in pH 3.0-5.0 and 0.5-3.0 g L-1 bile salt, and its HigBA system responded to the bile salt stress, but not to acid stress. The toxin protein HigB and its cognate antitoxin protein HigA had 85.1% and 100% similarity with those of Lactobacillus plantarum, respectively, and they formed the stable tetramer HigB-(HigA)2 -HigB structure in W. cibaria 018. When exposed to 1.5-3.0 g L-1 bile salt, the transcriptions of higB and higA were up-regulated with 4.39-19.29 and 5.94-30.91 folds, respectively. Meanwhile, W. cibaria 018 gathered into a mass with 48.07% survival rate and its persister cells were found to increase 8.21% under 3.0 g L-1 bile salt. CONCLUSION The HigBA TA system of W. cibaria 018 responded to the bile salt stress, but not to acid stress, which might offer novel perspectives to understand the tolerant mechanism of probiotics to GIT environment. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Ting Cai
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Qiu-Huan Zhao
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Wen-Liang Xiang
- School of Food and Bioengineering, Xihua University, Chengdu, China
- Key Laboratory of Food Biotechnology of Sichuan, Xihua University, Chengdu, China
| | - Lin Zhu
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Yu Rao
- School of Food and Bioengineering, Xihua University, Chengdu, China
| | - Jie Tang
- School of Food and Bioengineering, Xihua University, Chengdu, China
- Key Laboratory of Food Biotechnology of Sichuan, Xihua University, Chengdu, China
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20
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Hai Y, Wang X, Xie J. [The role of bacterial toxin-antitoxin systems in phage abortive infections]. Sheng Wu Gong Cheng Xue Bao 2022; 38:3291-3300. [PMID: 36151800 DOI: 10.13345/j.cjb.220140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Bacteria are often infected by large numbers of phages, and host bacteria have evolved diverse molecular strategies in the race with phages, with abortive infection (Abi) being one of them. The toxin-antitoxin system (TA) is expressed in response to bacterial stress, mediating hypometabolism and even dormancy, as well as directly reducing the formation of offspring phages. In addition, some of the toxins' sequences and structures are highly homologous to Cas, and phages even encode antitoxin analogs to block the activity of the corresponding toxins. This suggests that the failure of phage infection due to bacterial death in abortive infections is highly compatible with TA function, whereas TA may be one of the main resistance and defense forces for phage infestation of the host. This review summarized the TA systems involved in phage abortive infections based on classification and function. Moreover, TA systems with abortive functions and future use in antibiotic development and disease treatment were predicted. This will facilitate the understanding of bacterial-phage interactions as well as phage therapy and related synthetic biology research.
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Affiliation(s)
- Yang Hai
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xiaoyu Wang
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, School of Life Sciences, Southwest University, Chongqing 400715, China
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21
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Bobonis J, Mitosch K, Mateus A, Karcher N, Kritikos G, Selkrig J, Zietek M, Monzon V, Pfalz B, Garcia-Santamarina S, Galardini M, Sueki A, Kobayashi C, Stein F, Bateman A, Zeller G, Savitski MM, Elfenbein JR, Andrews-Polymenis HL, Typas A. Bacterial retrons encode phage-defending tripartite toxin-antitoxin systems. Nature 2022; 609:144-150. [PMID: 35850148 DOI: 10.1038/s41586-022-05091-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/08/2022] [Indexed: 11/09/2022]
Abstract
Retrons are prokaryotic genetic retroelements encoding a reverse transcriptase that produces multi-copy single-stranded DNA1 (msDNA). Despite decades of research on the biosynthesis of msDNA2, the function and physiological roles of retrons have remained unknown. Here we show that Retron-Sen2 of Salmonella enterica serovar Typhimurium encodes an accessory toxin protein, STM14_4640, which we renamed as RcaT. RcaT is neutralized by the reverse transcriptase-msDNA antitoxin complex, and becomes active upon perturbation of msDNA biosynthesis. The reverse transcriptase is required for binding to RcaT, and the msDNA is required for the antitoxin activity. The highly prevalent RcaT-containing retron family constitutes a new type of tripartite DNA-containing toxin-antitoxin system. To understand the physiological roles of such toxin-antitoxin systems, we developed toxin activation-inhibition conjugation (TAC-TIC), a high-throughput reverse genetics approach that identifies the molecular triggers and blockers of toxin-antitoxin systems. By applying TAC-TIC to Retron-Sen2, we identified multiple trigger and blocker proteins of phage origin. We demonstrate that phage-related triggers directly modify the msDNA, thereby activating RcaT and inhibiting bacterial growth. By contrast, prophage proteins circumvent retrons by directly blocking RcaT. Consistently, retron toxin-antitoxin systems act as abortive infection anti-phage defence systems, in line with recent reports3,4. Thus, RcaT retrons are tripartite DNA-regulated toxin-antitoxin systems, which use the reverse transcriptase-msDNA complex both as an antitoxin and as a sensor of phage protein activities.
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Affiliation(s)
- Jacob Bobonis
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Collaboration for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Karin Mitosch
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - André Mateus
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå, Sweden
| | - Nicolai Karcher
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - George Kritikos
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Joel Selkrig
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Matylda Zietek
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Vivian Monzon
- European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, UK
| | - Birgit Pfalz
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Sarela Garcia-Santamarina
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Institute of Chemical and Biological Technology António Xavier, Oeiras, Portugal
| | - Marco Galardini
- Institute for Molecular Bacteriology, TWINCORE Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School (MHH) and the Helmholtz Centre for Infection Research (HZI), Hannover, Germany
| | - Anna Sueki
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Biozentrum, University of Basel, Basel, Switzerland
| | - Callie Kobayashi
- Department of Microbial Pathogenesis and Immunology, Texas A&M University, College Station, TX, USA
| | - Frank Stein
- Proteomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Alex Bateman
- European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, UK
| | - Georg Zeller
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Mikhail M Savitski
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Proteomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Johanna R Elfenbein
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI, USA.
| | | | - Athanasios Typas
- Genome Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
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22
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LeRoux M, Srikant S, Teodoro GIC, Zhang T, Littlehale ML, Doron S, Badiee M, Leung AKL, Sorek R, Laub MT. The DarTG toxin-antitoxin system provides phage defence by ADP-ribosylating viral DNA. Nat Microbiol 2022; 7:1028-1040. [PMID: 35725776 PMCID: PMC9250638 DOI: 10.1038/s41564-022-01153-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 05/18/2022] [Indexed: 01/03/2023]
Abstract
Toxin-antitoxin (TA) systems are broadly distributed, yet poorly conserved, genetic elements whose biological functions are unclear and controversial. Some TA systems may provide bacteria with immunity to infection by their ubiquitous viral predators, bacteriophages. To identify such TA systems, we searched bioinformatically for those frequently encoded near known phage defence genes in bacterial genomes. This search identified homologues of DarTG, a recently discovered family of TA systems whose biological functions and natural activating conditions were unclear. Representatives from two different subfamilies, DarTG1 and DarTG2, strongly protected E. coli MG1655 against different phages. We demonstrate that for each system, infection with either RB69 or T5 phage, respectively, triggers release of the DarT toxin, a DNA ADP-ribosyltransferase, that then modifies viral DNA and prevents replication, thereby blocking the production of mature virions. Further, we isolated phages that have evolved to overcome DarTG defence either through mutations to their DNA polymerase or to an anti-DarT factor, gp61.2, encoded by many T-even phages. Collectively, our results indicate that phage defence may be a common function for TA systems and reveal the mechanism by which DarTG systems inhibit phage infection.
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Affiliation(s)
- Michele LeRoux
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sriram Srikant
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Tong Zhang
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Megan L Littlehale
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shany Doron
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Mohsen Badiee
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Anthony K L Leung
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
- Department of Molecular Biology and Genetics, Department of Genetic Medicine, Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Rotem Sorek
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA, USA.
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23
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Shmidov E, Lebenthal-Loinger I, Roth S, Karako-Lampert S, Zander I, Shoshani S, Danielli A, Banin E. PrrT/A, a Pseudomonas aeruginosa Bacterial Encoded Toxin-Antitoxin System Involved in Prophage Regulation and Biofilm Formation. Microbiol Spectr 2022; 10:e0118222. [PMID: 35575497 PMCID: PMC9241795 DOI: 10.1128/spectrum.01182-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 04/19/2022] [Indexed: 01/28/2023] Open
Abstract
Toxin-antitoxin (TA) systems are genetic modules that consist of a stable protein-toxin and an unstable antitoxin that neutralizes the toxic effect. In type II TA systems, the antitoxin is a protein that inhibits the toxin by direct binding. Type II TA systems, whose roles and functions are under intensive study, are highly distributed among bacterial chromosomes. Here, we identified and characterized a novel type II TA system PrrT/A encoded in the chromosome of the clinical isolate 39016 of the opportunistic pathogen Pseudomonas aeruginosa. We have shown that the PrrT/A system exhibits classical type II TA characteristics and novel regulatory properties. Following deletion of the prrA antitoxin, we discovered that the system is involved in a range of processes including (i) biofilm and motility, (ii) reduced prophage induction and bacteriophage production, and (iii) increased fitness for aminoglycosides. Taken together, these results highlight the importance of this toxin-antitoxin system to key physiological traits in P. aeruginosa. IMPORTANCE The functions attributed to bacterial TA systems are controversial and remain largely unknown. Our study suggests new insights into the potential functions of bacterial TA systems. We reveal that a chromosome-encoded TA system can regulate biofilm and motility, antibiotic resistance, prophage gene expression, and phage production. The latter presents a thus far unreported function of bacterial TA systems. In addition, with the emergence of antimicrobial-resistant bacteria, especially with the rising of P. aeruginosa resistant strains, the investigation of TA systems is critical as it may account for potential new targets against the resistant strains.
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Affiliation(s)
- Esther Shmidov
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
| | - Ilana Lebenthal-Loinger
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Shira Roth
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
- Faculty of Engineering, Bar-Ilan University, Ramat Gan, Israel
| | - Sarit Karako-Lampert
- Scientific Equipment Center, The Mina & Everard Goodman Faculty of Life Sciences Bar-Ilan University, Ramat Gan, Israel
| | - Itzhak Zander
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
| | - Sivan Shoshani
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
| | - Amos Danielli
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
- Faculty of Engineering, Bar-Ilan University, Ramat Gan, Israel
| | - Ehud Banin
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
- The Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat Gan, Israel
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24
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Bikmetov D, Hall AMJ, Livenskyi A, Gollan B, Ovchinnikov S, Gilep K, Kim J, Larrouy-Maumus G, Zgoda V, Borukhov S, Severinov K, Helaine S, Dubiley S. GNAT toxins evolve toward narrow tRNA target specificities. Nucleic Acids Res 2022; 50:5807-5817. [PMID: 35609997 PMCID: PMC9177977 DOI: 10.1093/nar/gkac356] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 04/10/2022] [Accepted: 05/05/2022] [Indexed: 12/16/2022] Open
Abstract
Type II toxin–antitoxin (TA) systems are two-gene modules widely distributed among prokaryotes. GNAT toxins associated with the DUF1778 antitoxins represent a large family of type II TAs. GNAT toxins inhibit cell growth by disrupting translation via acetylation of aminoacyl-tRNAs. In this work, we explored the evolutionary trajectory of GNAT toxins. Using LC/MS detection of acetylated aminoacyl-tRNAs combined with ribosome profiling, we systematically investigated the in vivo substrate specificity of an array of diverse GNAT toxins. Our functional data show that the majority of GNAT toxins are specific to Gly-tRNA isoacceptors. However, the phylogenetic analysis shows that the ancestor of GNAT toxins was likely a relaxed specificity enzyme capable of acetylating multiple elongator tRNAs. Together, our data provide a remarkable snapshot of the evolution of substrate specificity.
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Affiliation(s)
| | | | - Alexei Livenskyi
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow 119992, Russia
| | - Bridget Gollan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Stepan Ovchinnikov
- Center for Life Sciences, Skolkovo Institute of Science and Technology, Skolkovo 143025, Russia
| | - Konstantin Gilep
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, Moscow 119334, Russia
| | - Jenny Y Kim
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Gerald Larrouy-Maumus
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Viktor Zgoda
- Institute of Biomedical Chemistry, Moscow 119435, Russia
| | - Sergei Borukhov
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084-1489, USA
| | | | | | - Svetlana Dubiley
- To whom correspondence should be addressed. Tel: +7 499 135 6089;
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25
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Abstract
BACKGROUND Resistance to multiple drugs is one of the biggest challenges in managing infectious diseases. Acinetobacter baumannii is considered a nosocomial infection. According to the multiple roles of the toxin-antitoxin system, this system can be considered an antimicrobial target in the presence of bacteria. With the impact on bacterial toxin, it can be used as a new antibacterial target. The purpose of this study was to determine the mazEF genes as a potent antimicrobial target in A. baumannii clinical isolates. METHODS The functionality of mazEF genes was evaluated by qPCR in fifteen A. baumannii clinical isolates. Then, the mazE locus was targeted by peptide nucleic acid (PNA). RESULTS The results showed a significant difference in the mean number of copies of mazF gene in normal and stress conditions. Also, we found that at a concentration of 15 µM of PNA the bacteria were killed and confirmed by culture on LB agar. CONCLUSIONS This research is the first step in introducing mazEF TA loci as a sensitive target in A. baumannii. However, more studies are needed to test the effectiveness in vivo. In addition, the occurrence and potential for activation of the TA system, mazEF in other pathogenic bacteria should be further investigated.
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26
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Chattopadhyay G, Bhasin M, Ahmed S, Gosain TP, Ganesan S, Das S, Thakur C, Chandra N, Singh R, Varadarajan R. Functional and Biochemical Characterization of the MazEF6 Toxin-Antitoxin System of Mycobacterium tuberculosis. J Bacteriol 2022; 204:e0005822. [PMID: 35357163 PMCID: PMC9053165 DOI: 10.1128/jb.00058-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/07/2022] [Indexed: 12/15/2022] Open
Abstract
The Mycobacterium tuberculosis genome harbors nine toxin-antitoxin (TA) systems that are members of the mazEF family, unlike other prokaryotes, which have only one or two. Although the overall tertiary folds of MazF toxins are predicted to be similar, it is unclear how they recognize structurally different RNAs and antitoxins with divergent sequence specificity. Here, we have expressed and purified the individual components and complex of the MazEF6 TA system from M. tuberculosis. Size exclusion chromatography-multiangle light scattering (SEC-MALS) was performed to determine the oligomerization status of the toxin, antitoxin, and the complex in different stoichiometric ratios. The relative stabilities of the proteins were determined by nano-differential scanning fluorimetry (nano-DSF). Microscale thermophoresis (MST) and yeast surface display (YSD) were performed to measure the relative affinities between the cognate toxin-antitoxin partners. The interaction between MazEF6 complexes and cognate promoter DNA was also studied using MST. Analysis of paired-end RNA sequencing data revealed that the overexpression of MazF6 resulted in differential expression of 323 transcripts in M. tuberculosis. Network analysis was performed to identify the nodes from the top-response network. The analysis of mRNA protection ratios resulted in identification of putative MazF6 cleavage site in its native host, M. tuberculosis. IMPORTANCE M. tuberculosis harbors a large number of type II toxin-antitoxin (TA) systems, the exact roles for most of which are unclear. Prior studies have reported that overexpression of several of these type II toxins inhibits bacterial growth and contributes to the formation of drug-tolerant populations in vitro. To obtain insights into M. tuberculosis MazEF6 type II TA system function, we determined stability, oligomeric states, and binding affinities of cognate partners with each other and with their promoter operator DNA. Using RNA-seq data obtained from M. tuberculosis overexpression strains, we have identified putative MazF6 cleavage sites and targets in its native, cellular context.
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Affiliation(s)
| | - Munmun Bhasin
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Shahbaz Ahmed
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Tannu Priya Gosain
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Srivarshini Ganesan
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India
| | - Sayan Das
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Chandrani Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Nagasuma Chandra
- Department of Biochemistry, Indian Institute of Science, Bangalore, Karnataka, India
| | - Ramandeep Singh
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Raghavan Varadarajan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
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27
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Hussein Almola A, Al-Omari AW, Younis Mahdy Al-Hamadany A. Molecular Study of Acinetobacter baumannii that Lacking Some Essentials Genes Responsible of Toxin-Antitoxin System. Arch Razi Inst 2022; 77:483-490. [PMID: 35891726 PMCID: PMC9288598 DOI: 10.22092/ari.2021.356809.1915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/02/2021] [Indexed: 06/15/2023]
Abstract
Acinetobacter genus has various species that are widespread in different environments and can exist in non-living environment samples as well. Acinetobacter baumannii (A. baumannii) is known to be one of the main causes of nosocomial infection. Few studies have examined the possibility of the presence of this opportunistic pathogen in non-living environment samples. In this study, A. baumannii strain cl-2 was isolated from dishwasher basket samples and it was identified by 16S ribosomal RNA sequencing analysis. The present study also investigated the presence of some important genes responsible for toxin-antitoxin (TA) systems necessary for the resistance of this bacterium in improper environmental conditions. Additionally, attempts were made to study some essential virulence factors, such as hemolysin, lipase, protease, and lecithinase production, as well as biofilm formation and surface motility. The findings revealed that the isolate belongs to the A. baumannii strain cl-2. The isolate was deposed in the National Center for Biotechnology Information, (NCBI) and the data can be accessed via the NCBI accession number (MW642251). The results of screening the TA system by higBA, mazEF, and relBE genes showed the isolate did not contain these genes. The hemolysin toxin activity (phenotypic test) was performed by using the streaking and spot methods on blood agar. It was found that the A. baumannii strain cl-2 had the ability to hemolyze red blood cells and produce lecithinase and protease enzymes. Finally, it was revealed that the A. baumannii strain cl-2 had surface motility based on the concentric diffusion ring of growth observed on Luria Broth agar (0.3%). In conclusion, the isolates under study showed association patterns between their ability to produce hemolysin, lipase, lecithinase, as well as protease, and other virulence factors, including surface motility and biofilm formation.
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Affiliation(s)
| | - A W Al-Omari
- College of Sciences, University of Mosul, Mosul, Iraq
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28
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Abstract
Type I toxin-antitoxin (T1TA) systems constitute a large class of genetic modules with antisense RNA (asRNA)-mediated regulation of gene expression. They are widespread in bacteria and consist of an mRNA coding for a toxic protein and a noncoding asRNA that acts as an antitoxin preventing the synthesis of the toxin by directly base-pairing to its cognate mRNA. The co- and post-transcriptional regulation of T1TA systems is intimately linked to RNA sequence and structure, therefore it is essential to have an accurate annotation of the mRNA and asRNA molecules to understand this regulation. However, most T1TA systems have been identified by means of bioinformatic analyses solely based on the toxin protein sequences, and there is no central repository of information on their specific RNA features. Here we present the first database dedicated to type I TA systems, named T1TAdb. It is an open-access web database (https://d-lab.arna.cnrs.fr/t1tadb) with a collection of ∼1900 loci in ∼500 bacterial strains in which a toxin-coding sequence has been previously identified. RNA molecules were annotated with a bioinformatic procedure based on key determinants of the mRNA structure and the genetic organization of the T1TA loci. Besides RNA and protein secondary structure predictions, T1TAdb also identifies promoter, ribosome-binding, and mRNA-asRNA interaction sites. It also includes tools for comparative analysis, such as sequence similarity search and computation of structural multiple alignments, which are annotated with covariation information. To our knowledge, T1TAdb represents the largest collection of features, sequences, and structural annotations on this class of genetic modules.
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Affiliation(s)
- Nicolas J Tourasse
- University of Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, F-33000 Bordeaux, France
| | - Fabien Darfeuille
- University of Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, F-33000 Bordeaux, France
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29
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Takada K, Hama K, Sasaki T, Otsuka Y. The hokW-sokW Locus Encodes a Type I Toxin-Antitoxin System That Facilitates the Release of Lysogenic Sp5 Phage in Enterohemorrhagic Escherichia coli O157. Toxins (Basel) 2021; 13:toxins13110796. [PMID: 34822580 PMCID: PMC8621323 DOI: 10.3390/toxins13110796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 11/16/2022] Open
Abstract
The toxin-antitoxin (TA) genetic modules control various bacterial events, such as plasmid maintenance, persister cell formation, and phage defense. They also exist in mobile genetic elements, including prophages; however, their physiological roles remain poorly understood. Here, we demonstrate that hokW-sokW, a putative TA locus encoded in Sakai prophage 5 (Sp5) in enterohemorrhagic Escherichia coli O157: H7 Sakai strain, functions as a type I TA system. Bacterial growth assays showed that the antitoxic activity of sokW RNA against HokW toxin partially requires an endoribonuclease, RNase III, and an RNA chaperone, Hfq. We also demonstrated that hokW-sokW assists Sp5-mediated lysis of E. coli cells when prophage induction is promoted by the DNA-damaging agent mitomycin C (MMC). We found that MMC treatment diminished sokW RNA and increased both the expression level and inner membrane localization of HokW in a RecA-dependent manner. Remarkably, the number of released Sp5 phages decreased by half in the absence of hokW-sokW. These results suggest that hokW-sokW plays a novel role as a TA system that facilitates the release of Sp5 phage progeny through E. coli lysis.
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30
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Jeon H, Choi E, Hwang J. Identification and characterization of VapBC toxin-antitoxin system in Bosea sp. PAMC 26642 isolated from Arctic lichens. RNA 2021; 27:1374-1389. [PMID: 34429367 PMCID: PMC8522696 DOI: 10.1261/rna.078786.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Toxin-antitoxin (TA) systems are genetic modules composed of a toxin interfering with cellular processes and its cognate antitoxin, which counteracts the activity of the toxin. TA modules are widespread in bacterial and archaeal genomes. It has been suggested that TA modules participate in the adaptation of prokaryotes to unfavorable conditions. The Bosea sp. PAMC 26642 used in this study was isolated from the Arctic lichen Stereocaulon sp. There are 12 putative type II TA loci in the genome of Bosea sp. PAMC 26642. Of these, nine functional TA systems have been shown to be toxic in Escherichia coli The toxin inhibits growth, but this inhibition is reversed when the cognate antitoxin genes are coexpressed, indicating that these putative TA loci were bona fide TA modules. Only the BoVapC1 (AXW83_01405) toxin, a homolog of VapC, showed growth inhibition specific to low temperatures, which was recovered by the coexpression of BoVapB1 (AXW83_01400). Microscopic observation and growth monitoring revealed that the BoVapC1 toxin had bacteriostatic effects on the growth of E. coli and induced morphological changes. Quantitative real time polymerase chain reaction and northern blotting analyses showed that the BoVapC1 toxin had a ribonuclease activity on the initiator tRNAfMet, implying that degradation of tRNAfMet might trigger growth arrest in E. coli Furthermore, the BoVapBC1 system was found to contribute to survival against prolonged exposure at 4°C. This is the first study to identify the function of TA systems in cold adaptation.
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Affiliation(s)
- Hyerin Jeon
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
| | - Eunsil Choi
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan 46241, Republic of Korea
| | - Jihwan Hwang
- Department of Microbiology, Pusan National University, Busan 46241, Republic of Korea
- Microbiological Resource Research Institute, Pusan National University, Busan 46241, Republic of Korea
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31
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Hill V, Akarsu H, Barbarroja RS, Cippà VL, Kuhnert P, Heller M, Falquet L, Heller M, Stoffel MH, Labroussaa F, Jores J. Minimalistic mycoplasmas harbor different functional toxin-antitoxin systems. PLoS Genet 2021; 17:e1009365. [PMID: 34673769 PMCID: PMC8562856 DOI: 10.1371/journal.pgen.1009365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 11/02/2021] [Accepted: 09/29/2021] [Indexed: 11/19/2022] Open
Abstract
Mycoplasmas are minute bacteria controlled by very small genomes ranging from 0.6 to 1.4 Mbp. They encompass several important medical and veterinary pathogens that are often associated with a wide range of chronic diseases. The long persistence of mycoplasma cells in their hosts can exacerbate the spread of antimicrobial resistance observed for many species. However, the nature of the virulence factors driving this phenomenon in mycoplasmas is still unclear. Toxin-antitoxin systems (TA systems) are genetic elements widespread in many bacteria that were historically associated with bacterial persistence. Their presence on mycoplasma genomes has never been carefully assessed, especially for pathogenic species. Here we investigated three candidate TA systems in M. mycoides subsp. capri encoding a (i) novel AAA-ATPase/subtilisin-like serine protease module, (ii) a putative AbiEii/AbiEi pair and (iii) a putative Fic/RelB pair. We sequence analyzed fourteen genomes of M. mycoides subsp. capri and confirmed the presence of at least one TA module in each of them. Interestingly, horizontal gene transfer signatures were also found in several genomic loci containing TA systems for several mycoplasma species. Transcriptomic and proteomic data confirmed differential expression profiles of these TA systems during mycoplasma growth in vitro. While the use of heterologous expression systems based on E. coli and B. subtilis showed clear limitations, the functionality and neutralization capacities of all three candidate TA systems were successfully confirmed using M. capricolum subsp. capricolum as a host. Additionally, M. capricolum subsp. capricolum was used to confirm the presence of functional TA system homologs in mycoplasmas of the Hominis and Pneumoniae phylogenetic groups. Finally, we showed that several of these M. mycoides subsp. capri toxins tested in this study, and particularly the subtilisin-like serine protease, could be used to establish a kill switch in mycoplasmas for industrial applications.
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Affiliation(s)
- Virginia Hill
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
- Graduate School for Biomedical Science, University of Bern, Bern, Switzerland
| | - Hatice Akarsu
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | | | - Valentina L. Cippà
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | - Peter Kuhnert
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | - Martin Heller
- Friedrich-Loeffler-Institute—Federal Research Institute for Animal Health, Jena, Germany
| | - Laurent Falquet
- Biochemistry Unit, University of Fribourg and Swiss Institute of Bioinformatics, Fribourg, Switzerland
| | - Manfred Heller
- Proteomics and Mass Spectrometry Core Facility, Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Michael H. Stoffel
- Division of Veterinary Anatomy, Department of Clinical Research and Veterinary Public Health, University of Bern, Bern, Switzerland
| | - Fabien Labroussaa
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
| | - Joerg Jores
- Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
- * E-mail:
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Karimaei S, Kazem Aghamir SM, Foroushani AR, Pourmand MR. Antibiotic tolerance in biofilm persister cells of Staphylococcus aureus and expression of toxin-antitoxin system genes. Microb Pathog 2021; 159:105126. [PMID: 34384900 DOI: 10.1016/j.micpath.2021.105126] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/04/2021] [Accepted: 08/05/2021] [Indexed: 11/17/2022]
Abstract
The ability of Staphylococcus aureus to form biofilm and persister cells is the main cause of recurrent infections. This study aimed to evaluate the expression of toxin-antitoxin (TA) systems in persister cells within S. aureus biofilms. Time-dependent variation in the persister population present in biofilms of S. aureus was examined after treatment with bactericidal antibiotics. Then, the relative expression level of type II TA system (mazF, relE1, and relE2), type I TA system (sprG), and clpP protease genes in S. aureus strains were assessed by Real _Time PCR. Among the sixteen isolates, two isolates were found to be the strongest biofilm producers. The established biofilm of these isolates showed a comparable biphasic pattern at the lethal dose of the antibiotics. The expression level of TA system genes was increased and strain-specific expression patterns were observed under antibiotics stress conditions. Persisters within a biofilm may establish a reservoir for relapsing infection and could contribute to treatment failures. Hence, the possible role of the TA systems should be considered in biofilm and persister cell formation.
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Affiliation(s)
- Samira Karimaei
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Abbas Rahimi Foroushani
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Pourmand
- Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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Kobayashi K. Diverse LXG toxin and antitoxin systems specifically mediate intraspecies competition in Bacillus subtilis biofilms. PLoS Genet 2021; 17:e1009682. [PMID: 34280190 PMCID: PMC8321402 DOI: 10.1371/journal.pgen.1009682] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 07/29/2021] [Accepted: 06/25/2021] [Indexed: 12/14/2022] Open
Abstract
Biofilms are multispecies communities, in which bacteria constantly compete with one another for resources and niches. Bacteria produce many antibiotics and toxins for competition. However, since biofilm cells exhibit increased tolerance to antimicrobials, their roles in biofilms remain controversial. Here, we showed that Bacillus subtilis produces multiple diverse polymorphic toxins, called LXG toxins, that contain N-terminal LXG delivery domains and diverse C-terminal toxin domains. Each B. subtilis strain possesses a distinct set of LXG toxin–antitoxin genes, the number and variation of which is sufficient to distinguish each strain. The B. subtilis strain NCIB3610 possesses six LXG toxin–antitoxin operons on its chromosome, and five of the toxins functioned as DNase. In competition assays, deletion mutants of any of the six LXG toxin–antitoxin operons were outcompeted by the wild-type strain. This phenotype was suppressed when the antitoxins were ectopically expressed in the deletion mutants. The fitness defect of the mutants was only observed in solid media that supported biofilm formation. Biofilm matrix polymers, exopolysaccharides and TasA protein polymers were required for LXG toxin function. These results indicate that LXG toxin-antitoxin systems specifically mediate intercellular competition between B. subtilis strains in biofilms. Mutual antagonism between some LXG toxin producers drove the spatial segregation of two strains in a biofilm, indicating that LXG toxins not only mediate competition in biofilms, but may also help to avoid warfare between strains in biofilms. LXG toxins from strain NCIB3610 were effective against some natural isolates, and thus LXG toxin–antitoxin systems have ecological impact. B. subtilis possesses another polymorphic toxin, WapA. WapA had toxic effects under planktonic growth conditions but not under biofilm conditions because exopolysaccharides and TasA protein polymers inhibited WapA function. These results indicate that B. subtilis uses two types of polymorphic toxins for competition, depending on the growth mode. Biofilms are surface-associated multispecies communities, in which bacteria are protected by self-produced extracellular polymeric substances. In biofilms, bacteria constantly engage in intra- and interspecies competition. To minimize exploitation by competitors, bacteria produce a variety of antibiotics and toxins for competition. However, since biofilm cells exhibit increased tolerance to antimicrobials, the function of antibiotics and toxins in biofilms remains controversial. Therefore, the mechanisms underlying bacterial competition in biofilms remain to be investigated. We found that the soil bacterium B. subtilis produces polymorphic toxins, termed LXG toxins. LXG toxins are highly diversified among B. subtilis strains, and each B. subtilis strain possesses three to nine different LXG toxins. LXG toxins specifically mediate intraspecies competition in biofilms. Competition between some LXG toxin producers resulted in the spatial segregation of strains in biofilms, indicating that LXG toxins not only mediate competition, but also help to minimize warfare in biofilms. LXG toxins were effective against natural isolates of B. subtilis, suggesting that LXG toxin–antitoxin systems have ecological impact. Our results provide new insights into how bacteria survive competition in biofilms.
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Affiliation(s)
- Kazuo Kobayashi
- Division of Biological Science, Department of Science and Technology, Nara Institute of Science & Technology, Ikoma, Nara, Japan
- * E-mail:
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34
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Nonin-Lecomte S, Fermon L, Felden B, Pinel-Marie ML. Bacterial Type I Toxins: Folding and Membrane Interactions. Toxins (Basel) 2021; 13:toxins13070490. [PMID: 34357962 PMCID: PMC8309996 DOI: 10.3390/toxins13070490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 11/16/2022] Open
Abstract
Bacterial type I toxin-antitoxin systems are two-component genetic modules that encode a stable toxic protein whose ectopic overexpression can lead to growth arrest or cell death, and an unstable RNA antitoxin that inhibits toxin translation during growth. These systems are widely spread among bacterial species. Type I antitoxins are cis- or trans-encoded antisense small RNAs that interact with toxin-encoding mRNAs by pairing, thereby inhibiting toxin mRNA translation and/or inducing its degradation. Under environmental stress conditions, the up-regulation of the toxin and/or the antitoxin degradation by specific RNases promote toxin translation. Most type I toxins are small hydrophobic peptides with a predicted α-helical transmembrane domain that induces membrane depolarization and/or permeabilization followed by a decrease of intracellular ATP, leading to plasmid maintenance, growth adaptation to environmental stresses, or persister cell formation. In this review, we describe the current state of the art on the folding and the membrane interactions of these membrane-associated type I toxins from either Gram-negative or Gram-positive bacteria and establish a chronology of their toxic effects on the bacterial cell. This review also includes novel structural results obtained by NMR concerning the sprG1-encoded membrane peptides that belong to the sprG1/SprF1 type I TA system expressed in Staphylococcus aureus and discusses the putative membrane interactions allowing the lysis of competing bacteria and host cells.
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Affiliation(s)
| | - Laurence Fermon
- BRM (Bacterial Regulatory RNAs and Medicine), Inserm, UMR_S 1230, Université de Rennes 1, 35000 Rennes, France; (L.F.); (B.F.)
| | - Brice Felden
- BRM (Bacterial Regulatory RNAs and Medicine), Inserm, UMR_S 1230, Université de Rennes 1, 35000 Rennes, France; (L.F.); (B.F.)
| | - Marie-Laure Pinel-Marie
- BRM (Bacterial Regulatory RNAs and Medicine), Inserm, UMR_S 1230, Université de Rennes 1, 35000 Rennes, France; (L.F.); (B.F.)
- Correspondence:
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Chlebicka K, Bonar E, Suder P, Ostyn E, Felden B, Wladyka B, Pinel-Marie ML. Impacts of the Type I Toxin-Antitoxin System, SprG1/SprF1, on Staphylococcus aureus Gene Expression. Genes (Basel) 2021; 12:genes12050770. [PMID: 34070083 PMCID: PMC8158120 DOI: 10.3390/genes12050770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/14/2021] [Accepted: 05/16/2021] [Indexed: 11/16/2022] Open
Abstract
Type I toxin-antitoxin (TA) systems are widespread genetic modules in bacterial genomes. They express toxic peptides whose overexpression leads to growth arrest or cell death, whereas antitoxins regulate the expression of toxins, acting as labile antisense RNAs. The Staphylococcus aureus (S. aureus) genome contains and expresses several functional type I TA systems, but their biological functions remain unclear. Here, we addressed and challenged experimentally, by proteomics, if the type I TA system, the SprG1/SprF1 pair, influences the overall gene expression in S. aureus. Deleted and complemented S. aureus strains were analyzed for their proteomes, both intracellular and extracellular, during growth. Comparison of intracellular proteomes among the strains points to the SprF1 antitoxin as moderately downregulating protein expression. In the strain naturally expressing the SprG1 toxin, cytoplasmic proteins are excreted into the medium, but this is not due to unspecific cell leakages. Such a toxin-driven release of the cytoplasmic proteins may modulate the host inflammatory response that, in turn, could amplify the S. aureus infection spread.
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Affiliation(s)
- Kinga Chlebicka
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland; (K.C.); (E.B.)
| | - Emilia Bonar
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland; (K.C.); (E.B.)
| | - Piotr Suder
- Department of Analytical Chemistry and Biochemistry, Faculty of Materials Science and Ceramics, AGH University of Science and Technology, 31-007 Krakow, Poland;
| | - Emeline Ostyn
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine]—UMR_S 1230, 35000 Rennes, France;
| | - Brice Felden
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine]—UMR_S 1230, 35000 Rennes, France;
| | - Benedykt Wladyka
- Department of Analytical Biochemistry, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, 30-387 Krakow, Poland; (K.C.); (E.B.)
- Correspondence: (B.W.); (M.-L.P.-M.); Tel.: +48-126646511 (B.W.); +33-223234850 (M.-L.P.-M.)
| | - Marie-Laure Pinel-Marie
- Inserm, BRM [Bacterial Regulatory RNAs and Medicine]—UMR_S 1230, 35000 Rennes, France;
- Correspondence: (B.W.); (M.-L.P.-M.); Tel.: +48-126646511 (B.W.); +33-223234850 (M.-L.P.-M.)
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36
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Edelmann D, Oberpaul M, Schäberle TF, Berghoff BA. Post-transcriptional deregulation of the tisB/istR-1 toxin-antitoxin system promotes SOS-independent persister formation in Escherichia coli. Environ Microbiol Rep 2021; 13:159-168. [PMID: 33350069 DOI: 10.1111/1758-2229.12919] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 06/12/2023]
Abstract
Bacterial dormancy is a valuable strategy to endure unfavourable conditions. The term 'persister' has been coined for cells that tolerate antibiotic treatments due to reduced cellular activity. The type I toxin-antitoxin system tisB/istR-1 is linked to persistence in Escherichia coli, because toxin TisB depolarizes the inner membrane and causes ATP depletion. Transcription of tisB is induced upon activation of the SOS response by DNA-damaging drugs. However, translation is repressed both by a 5' structure within the tisB mRNA and by RNA antitoxin IstR-1. This tight regulation limits TisB production to SOS conditions. Deletion of both regulatory RNA elements produced a 'high persistence' mutant, which was previously assumed to depend on stochastic SOS induction and concomitant TisB production. Here, we demonstrate that the mutant generates a subpopulation of growth-retarded cells during late stationary phase, likely due to SOS-independent TisB accumulation. Cell sorting experiments revealed that the stationary phase-derived subpopulation contains most of the persister cells. Collectively our data show that deletion of the regulatory RNA elements uncouples the persister formation process from the intended stress situation and enables the formation of TisB-dependent persisters in an SOS-independent manner.
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Affiliation(s)
- Daniel Edelmann
- Institute for Microbiology and Molecular Biology, Justus Liebig University Giessen, Giessen, 35392, Germany
| | - Markus Oberpaul
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, Giessen, 35392, Germany
| | - Till F Schäberle
- Institute for Insect Biotechnology, Justus Liebig University Giessen, Giessen, 35392, Germany
- Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Branch for Bioresources, Giessen, 35392, Germany
- German Centre for Infection Research (DZIF), Partner Site Giessen-Marburg-Langen, Giessen, 35392, Germany
| | - Bork A Berghoff
- Institute for Microbiology and Molecular Biology, Justus Liebig University Giessen, Giessen, 35392, Germany
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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38
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Affiliation(s)
- Juan C Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 28049 Madrid, Spain
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bogati B, Wadsworth N, Barrera F, Fozo EM. Improved growth of Escherichia coli in aminoglycoside antibiotics by the zor-orz toxin-antitoxin system. J Bacteriol 2021; 204:JB0040721. [PMID: 34570627 PMCID: PMC8765423 DOI: 10.1128/jb.00407-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/21/2021] [Indexed: 11/20/2022] Open
Abstract
Type I toxin-antitoxin systems consist of a small protein (under 60 amino acids) whose overproduction can result in cell growth stasis or death, and a small RNA that represses translation of the toxin mRNA. Despite their potential toxicity, type I toxin proteins are increasingly linked to improved survival of bacteria in stressful environments and antibiotic persistence. While the interaction of toxin mRNAs with their cognate antitoxin sRNAs in some systems are well characterized, additional translational control of many toxins and their biological roles are not well understood. Using an ectopic overexpression system, we show that the efficient translation of a chromosomally encoded type I toxin, ZorO, requires mRNA processing of its long 5' untranslated region (UTR; Δ28 UTR). The severity of ZorO induced toxicity on growth inhibition, membrane depolarization, and ATP depletion were significantly increased if expressed from the Δ28 UTR versus the full-length UTR. ZorO did not form large pores as evident via a liposomal leakage assay, in vivo morphological analyses, and measurement of ATP loss. Further, increasing the copy number of the entire zor-orz locus significantly improved growth of bacterial cells in the presence of kanamycin and increased the minimum inhibitory concentration against kanamycin and gentamycin; however, no such benefit was observed against other antibiotics. This supports a role for the zor-orz locus as a protective measure against specific stress agents and is likely not part of a general stress response mechanism. Combined, these data shed more insights into the possible native functions for type I toxin proteins. IMPORTANCE Bacterial species can harbor gene pairs known as type I toxin-antitoxin systems where one gene encodes a small protein that is toxic to the bacteria producing it and a second gene that encodes a small RNA antitoxin to prevent toxicity. While artificial overproduction of type I toxin proteins can lead to cell growth inhibition and cell lysis, the endogenous translation of type I toxins appears to be tightly regulated. Here, we show translational regulation controls production of the ZorO type I toxin and prevents subsequent negative effects on the cell. Further, we demonstrate a role for zorO and its cognate antitoxin in improved growth of E. coli in the presence of aminoglycoside antibiotics.
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Affiliation(s)
- Bikash Bogati
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Nicholas Wadsworth
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Francisco Barrera
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee, USA
| | - Elizabeth M. Fozo
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
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Romilly C, Lippegaus A, Wagner E. An RNA pseudoknot is essential for standby-mediated translation of the tisB toxin mRNA in Escherichia coli. Nucleic Acids Res 2020; 48:12336-12347. [PMID: 33231643 PMCID: PMC7708055 DOI: 10.1093/nar/gkaa1139] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/03/2020] [Accepted: 11/07/2020] [Indexed: 01/20/2023] Open
Abstract
In response to DNA damage, Escherichia coli cells activate the expression of the toxin gene tisB of the toxin-antitoxin system tisB-istR1. Of three isoforms, only the processed, highly structured +42 tisB mRNA is active. Translation requires a standby site, composed of two essential elements: a single-stranded region located 100 nucleotides upstream of the sequestered RBS, and a structure near the 5'-end of the active mRNA. Here, we propose that this 5'-structure is an RNA pseudoknot which is required for 30S and protein S1-alone binding to the mRNA. Point mutations that prevent formation of this pseudoknot inhibit formation of translation initiation complexes, impair S1 and 30S binding to the mRNA, and render the tisB mRNA non-toxic in vivo. A set of mutations created in either the left or right arm of stem 2 of the pseudoknot entailed loss of toxicity upon overexpression of the corresponding mRNA variants. Combining the matching right-left arm mutations entirely restored toxicity levels to that of the wild-type, active mRNA. Finally, since many pseudoknots have high affinity for S1, we predicted similar pseudoknots in non-homologous type I toxin-antitoxin systems that exhibit features similar to that of tisB-IstR1, suggesting a shared requirement for standby acting at great distances.
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MESH Headings
- Bacterial Toxins/genetics
- Bacterial Toxins/metabolism
- Base Pairing
- Base Sequence
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Escherichia coli Proteins/genetics
- Escherichia coli Proteins/metabolism
- Gene Expression Regulation, Bacterial
- Nucleic Acid Conformation
- Point Mutation
- Protein Binding
- Protein Biosynthesis
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Messenger/chemistry
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosome Subunits, Small, Bacterial/genetics
- Ribosome Subunits, Small, Bacterial/metabolism
- Toxin-Antitoxin Systems/genetics
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Affiliation(s)
- Cédric Romilly
- Department of Cell and Molecular Biology, Uppsala University, Uppsala S-75124, Sweden
| | - Anne Lippegaus
- Department of Cell and Molecular Biology, Uppsala University, Uppsala S-75124, Sweden
| | - E Gerhart H Wagner
- Department of Cell and Molecular Biology, Uppsala University, Uppsala S-75124, Sweden
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42
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Peltier J, Hamiot A, Garneau JR, Boudry P, Maikova A, Hajnsdorf E, Fortier LC, Dupuy B, Soutourina O. Type I toxin-antitoxin systems contribute to the maintenance of mobile genetic elements in Clostridioides difficile. Commun Biol 2020; 3:718. [PMID: 33247281 PMCID: PMC7699646 DOI: 10.1038/s42003-020-01448-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 11/03/2020] [Indexed: 12/15/2022] Open
Abstract
Toxin-antitoxin (TA) systems are widespread on mobile genetic elements and in bacterial chromosomes. In type I TA, synthesis of the toxin protein is prevented by the transcription of an antitoxin RNA. The first type I TA were recently identified in the human enteropathogen Clostridioides difficile. Here we report the characterization of five additional type I TA within phiCD630-1 (CD0977.1-RCd11, CD0904.1-RCd13 and CD0956.3-RCd14) and phiCD630-2 (CD2889-RCd12 and CD2907.2-RCd15) prophages of C. difficile strain 630. Toxin genes encode 34 to 47 amino acid peptides and their ectopic expression in C. difficile induces growth arrest that is neutralized by antitoxin RNA co-expression. We show that type I TA located within the phiCD630-1 prophage contribute to its stability and heritability. We have made use of a type I TA toxin gene to generate an efficient mutagenesis tool for this bacterium that allowed investigation of the role of these widespread TA in prophage maintenance.
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Affiliation(s)
- Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS-2001, Institut Pasteur, Université de Paris, 75015, Paris, France
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Audrey Hamiot
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS-2001, Institut Pasteur, Université de Paris, 75015, Paris, France
- UMR UMET, INRA, CNRS, Univ. Lille 1, 59650, Villeneuve d'Ascq, France
| | - Julian R Garneau
- Faculty of Medicine and Health Sciences, Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean Mignault, Sherbrooke, QC, J1E 4K8, Canada
| | - Pierre Boudry
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS-2001, Institut Pasteur, Université de Paris, 75015, Paris, France
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette Cedex, France
| | - Anna Maikova
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS-2001, Institut Pasteur, Université de Paris, 75015, Paris, France
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, 143028, Russia
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg, 195251, Russia
| | - Eliane Hajnsdorf
- Institut de Biologie Physico-Chimique, UMR8261, CNRS, Université de Paris, 13 rue Pierre et Marie Curie, 75005, Paris, France
| | - Louis-Charles Fortier
- Faculty of Medicine and Health Sciences, Department of Microbiology and Infectious Diseases, Université de Sherbrooke, 3201 rue Jean Mignault, Sherbrooke, QC, J1E 4K8, Canada
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS-2001, Institut Pasteur, Université de Paris, 75015, Paris, France
| | - Olga Soutourina
- Laboratoire Pathogenèse des Bactéries Anaérobies, CNRS-2001, Institut Pasteur, Université de Paris, 75015, Paris, France.
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
- Institut Universitaire de France (IUF), Paris, France.
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43
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Hampton HG, Smith LM, Ferguson S, Meaden S, Jackson SA, Fineran PC. Functional genomics reveals the toxin-antitoxin repertoire and AbiE activity in Serratia. Microb Genom 2020; 6:mgen000458. [PMID: 33074086 PMCID: PMC7725324 DOI: 10.1099/mgen.0.000458] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/02/2020] [Indexed: 12/17/2022] Open
Abstract
Bacteriophage defences are divided into innate and adaptive systems. Serratia sp. ATCC 39006 has three CRISPR-Cas adaptive immune systems, but its innate immune repertoire is unknown. Here, we re-sequenced and annotated the Serratia genome and predicted its toxin-antitoxin (TA) systems. TA systems can provide innate phage defence through abortive infection by causing infected cells to 'shut down', limiting phage propagation. To assess TA system function on a genome-wide scale, we utilized transposon insertion and RNA sequencing. Of the 32 TA systems predicted bioinformatically, 4 resembled pseudogenes and 11 were demonstrated to be functional based on transposon mutagenesis. Three functional systems belonged to the poorly characterized but widespread, AbiE, abortive infection/TA family. AbiE is a type IV TA system with a predicted nucleotidyltransferase toxin. To investigate the mode of action of this toxin, we measured the transcriptional response to AbiEii expression. We observed dysregulated levels of tRNAs and propose that the toxin targets tRNAs resulting in bacteriostasis. A recent report on a related toxin shows this occurs through addition of nucleotides to tRNA(s). This study has demonstrated the utility of functional genomics for probing TA function in a high-throughput manner, defined the TA repertoire in Serratia and shown the consequences of AbiE induction.
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Affiliation(s)
- Hannah G. Hampton
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Leah M. Smith
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Shaun Ferguson
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Sean Meaden
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Simon A. Jackson
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin 9054, New Zealand
| | - Peter C. Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
- Genetics Otago, University of Otago, Dunedin 9054, New Zealand
- Bio-protection Research Centre, University of Otago, Dunedin 9054, New Zealand
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44
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Li Z, Shi C, Gao S, Zhang X, Lu D, Liu G. Characteristic and role of chromosomal type II toxin-antitoxin systems locus in Enterococcus faecalis ATCC29212. J Microbiol 2020; 58:1027-1036. [PMID: 33095389 DOI: 10.1007/s12275-020-0079-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 08/31/2020] [Accepted: 09/18/2020] [Indexed: 11/24/2022]
Abstract
The Gram-positive bacterium Enterococcus faecalis is currently one of the major pathogens of nosocomial infections. The lifestyle of E. faecalis relies primarily on its remarkable capacity to face and survive in harsh environmental conditions. Toxin-antitoxin (TA) systems have been linked to the growth control of bacteria in response to adverse environments but have rarely been reported in Enterococcus. Three functional type II TA systems were identified among the 10 putative TA systems encoded by E. faecalis ATCC29212. These toxin genes have conserved domains homologous to MazF (DR75_1948) and ImmA/IrrE family metallo-endopeptidases (DR75_1673 and DR75_2160). Overexpression of toxin genes could inhibit the growth of Escherichia coli. However, the toxin DR75_1673 could not inhibit bacterial growth, and the bacteriostatic effect occurred only when it was coexpressed with the antitoxin DR75_1672. DR75_1948-DR75_1949 and DR75_160-DR75_2161 could maintain the stable inheritance of the unstable plasmid pLMO12102 in E. coli. Moreover, the transcription levels of these TAs showed significant differences when cultivated under normal conditions and with different temperatures, antibiotics, anaerobic agents and H2O2. When DR75_2161 was knocked out, the growth of the mutant strain at high temperature and oxidative stress was limited. The experimental characterization of these TAs loci might be helpful to investigate the key roles of type II TA systems in the physiology and environmental stress responses of Enterococcus.
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Affiliation(s)
- Zhen Li
- Microbiome Laboratory, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan, 450003, P. R. China.
| | - Chao Shi
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, 450008, P. R. China
| | - Shanjun Gao
- Microbiome Laboratory, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan, 450003, P. R. China
| | - Xiulei Zhang
- Microbiome Laboratory, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan, 450003, P. R. China
| | - Di Lu
- Microbiome Laboratory, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan, 450003, P. R. China
| | - Guangzhi Liu
- Microbiome Laboratory, Henan Provincial People's Hospital, Zhengzhou University People's Hospital, Zhengzhou, Henan, 450003, P. R. China
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45
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Daniel S, Goldlust K, Quebre V, Shen M, Lesterlin C, Bouet JY, Yamaichi Y. Vertical and Horizontal Transmission of ESBL Plasmid from Escherichia coli O104:H4. Genes (Basel) 2020; 11:genes11101207. [PMID: 33081159 PMCID: PMC7602700 DOI: 10.3390/genes11101207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 10/05/2020] [Accepted: 10/13/2020] [Indexed: 12/16/2022] Open
Abstract
Multidrug resistance (MDR) often results from the acquisition of mobile genetic elements (MGEs) that encode MDR gene(s), such as conjugative plasmids. The spread of MDR plasmids is founded on their ability of horizontal transference, as well as their faithful inheritance in progeny cells. Here, we investigated the genetic factors involved in the prevalence of the IncI conjugative plasmid pESBL, which was isolated from the Escherichia coli O104:H4 outbreak strain in Germany in 2011. Using transposon-insertion sequencing, we identified the pESBL partitioning locus (par). Genetic, biochemical and microscopic approaches allowed pESBL to be characterized as a new member of the Type Ib partitioning system. Inactivation of par caused mis-segregation of pESBL followed by post-segregational killing (PSK), resulting in a great fitness disadvantage but apparent plasmid stability in the population of viable cells. We constructed a variety of pESBL derivatives with different combinations of mutations in par, conjugational transfer (oriT) and pnd toxin-antitoxin (TA) genes. Only the triple mutant exhibited plasmid-free cells in viable cell populations. Time-lapse tracking of plasmid dynamics in microfluidics indicated that inactivation of pnd improved the survival of plasmid-free cells and allowed oriT-dependent re-acquisition of the plasmid. Altogether, the three factors—active partitioning, toxin-antitoxin and conjugational transfer—are all involved in the prevalence of pESBL in the E. coli population.
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Affiliation(s)
- Sandra Daniel
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette, France; (S.D.); (M.S.)
| | - Kelly Goldlust
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, 69007 Lyon, France; (K.G.); (C.L.)
| | - Valentin Quebre
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), CBI, CNRS, Université de Toulouse, UPS, 31062 Toulouse, France; (V.Q.); (J.-Y.B.)
| | - Minjia Shen
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette, France; (S.D.); (M.S.)
- Graduate School of Structure and Dynamics of Living Systems, Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette, France
| | - Christian Lesterlin
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, 69007 Lyon, France; (K.G.); (C.L.)
| | - Jean-Yves Bouet
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), CBI, CNRS, Université de Toulouse, UPS, 31062 Toulouse, France; (V.Q.); (J.-Y.B.)
| | - Yoshiharu Yamaichi
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, 91198 Gif-sur-Yvette, France; (S.D.); (M.S.)
- Correspondence:
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Klimkaitė L, Armalytė J, Skerniškytė J, Sužiedėlienė E. The Toxin-Antitoxin Systems of the Opportunistic Pathogen Stenotrophomonas maltophilia of Environmental and Clinical Origin. Toxins (Basel) 2020; 12:E635. [PMID: 33019620 PMCID: PMC7650669 DOI: 10.3390/toxins12100635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/22/2020] [Accepted: 09/25/2020] [Indexed: 12/16/2022] Open
Abstract
Stenotrophomonas maltophilia is a ubiquitous environmental bacterium that has recently emerged as a multidrug-resistant opportunistic pathogen causing bloodstream, respiratory, and urinary tract infections. The connection between the commensal environmental S. maltophilia and the opportunistic pathogen strains is still under investigation. Bacterial toxin-antitoxin (TA) systems have been previously associated with pathogenic traits, such as biofilm formation and resistance to antibiotics, which are important in clinical settings. The same species of the bacterium can possess various sets of TAs, possibly influencing their overall stress response. While the TA systems of other important opportunistic pathogens have been researched, nothing is known about the TA systems of S. maltophilia. Here, we report the identification and characterization of S. maltophilia type II TA systems and their prevalence in the isolates of clinical and environmental origins. We found 49 putative TA systems by bioinformatic analysis in S. maltophilia genomes. Despite their even spread in sequenced S. maltophilia genomes, we observed that relBE, hicAB, and previously undescribed COG3832-ArsR operons were present solely in clinical S. maltophilia isolates collected in Lithuania, while hipBA was more frequent in the environmental ones. The kill-rescue experiments in Escherichia coli proved higBA, hicAB, and relBE systems to be functional TA modules. Together with different TA profiles, the clinical S. maltophilia isolates exhibited stronger biofilm formation, increased antibiotic, and serum resistance compared to environmental isolates. Such tendencies suggest that certain TA systems could be used as indicators of virulence traits.
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Affiliation(s)
| | - Julija Armalytė
- Institute of Biosciences, Life Sciences Center, Vilnius University, LT-1025 Vilnius, Lithuania; (L.K.); (J.S.)
| | | | - Edita Sužiedėlienė
- Institute of Biosciences, Life Sciences Center, Vilnius University, LT-1025 Vilnius, Lithuania; (L.K.); (J.S.)
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Bleriot I, Blasco L, Delgado-Valverde M, Gual-de-Torrella A, Ambroa A, Fernandez-Garcia L, Lopez M, Oteo-Iglesias J, Wood TK, Pascual A, Bou G, Fernandez-Cuenca F, Tomas M. Mechanisms of Tolerance and Resistance to Chlorhexidine in Clinical Strains of Klebsiella pneumoniae Producers of Carbapenemase: Role of New Type II Toxin-Antitoxin System, PemIK. Toxins (Basel) 2020; 12:E566. [PMID: 32887507 PMCID: PMC7551900 DOI: 10.3390/toxins12090566] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 12/21/2022] Open
Abstract
Although the failure of antibiotic treatment is normally attributed to resistance, tolerance and persistence display a significant role in the lack of response to antibiotics. Due to the fact that several nosocomial pathogens show a high level of tolerance and/or resistance to chlorhexidine, in this study we analyzed the molecular mechanisms associated with chlorhexidine adaptation in two clinical strains of Klebsiella pneumoniae by phenotypic and transcriptomic studies. These two strains belong to ST258-KPC3 (high-risk clone carrying β-lactamase KPC3) and ST846-OXA48 (low-risk clone carrying β-lactamase OXA48). Our results showed that the K. pneumoniae ST258-KPC3CA and ST846-OXA48CA strains exhibited a different behavior under chlorhexidine (CHLX) pressure, adapting to this biocide through resistance and tolerance mechanisms, respectively. Furthermore, the appearance of cross-resistance to colistin was observed in the ST846-OXA48CA strain (tolerant to CHLX), using the broth microdilution method. Interestingly, this ST846-OXA48CA isolate contained a plasmid that encodes a novel type II toxin/antitoxin (TA) system, PemI/PemK. We characterized this PemI/PemK TA system by cloning both genes into the IPTG-inducible pCA24N plasmid, and found their role in persistence and biofilm formation. Accordingly, the ST846-OXA48CA strain showed a persistence biphasic curve in the presence of a chlorhexidine-imipenem combination, and these results were confirmed by the enzymatic assay (WST-1).
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Affiliation(s)
- Ines Bleriot
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
| | - Lucia Blasco
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
| | - Mercedes Delgado-Valverde
- Clinical Unit for Infectious Diseases, Department of Microbiology and Medicine, Microbiology and Preventive Medicine, Hospital Universitario Virgen Macarena, University of Seville, Biomedicine Insititute of Seville (IBIS), 41009 Seville, Spain; (M.D.-V.); (A.G.-d.-T.)
| | - Ana Gual-de-Torrella
- Clinical Unit for Infectious Diseases, Department of Microbiology and Medicine, Microbiology and Preventive Medicine, Hospital Universitario Virgen Macarena, University of Seville, Biomedicine Insititute of Seville (IBIS), 41009 Seville, Spain; (M.D.-V.); (A.G.-d.-T.)
| | - Anton Ambroa
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
| | - Laura Fernandez-Garcia
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
| | - Maria Lopez
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
- Spanish Network for Research in Infectious Diseases (REIPI), 41071 Seville, Spain
| | - Jesus Oteo-Iglesias
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
- Spanish Network for Research in Infectious Diseases (REIPI), 41071 Seville, Spain
- Reference and Research Laboratory for Antibiotic Resistance and Health Care Infections, National Centre for Microbiology, Institute of Health Carlos III, 28222 Majadahonda, Spain
| | - Thomas K. Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA 16801, USA;
| | - Alvaro Pascual
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
- Clinical Unit for Infectious Diseases, Department of Microbiology and Medicine, Microbiology and Preventive Medicine, Hospital Universitario Virgen Macarena, University of Seville, Biomedicine Insititute of Seville (IBIS), 41009 Seville, Spain; (M.D.-V.); (A.G.-d.-T.)
- Spanish Network for Research in Infectious Diseases (REIPI), 41071 Seville, Spain
| | - German Bou
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
- Spanish Network for Research in Infectious Diseases (REIPI), 41071 Seville, Spain
| | - Felipe Fernandez-Cuenca
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
- Clinical Unit for Infectious Diseases, Department of Microbiology and Medicine, Microbiology and Preventive Medicine, Hospital Universitario Virgen Macarena, University of Seville, Biomedicine Insititute of Seville (IBIS), 41009 Seville, Spain; (M.D.-V.); (A.G.-d.-T.)
- Spanish Network for Research in Infectious Diseases (REIPI), 41071 Seville, Spain
| | - Maria Tomas
- Microbiology Department-Research Institute Biomedical A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), 15006 A Coruña, Spain; (I.B.); (L.B.); (A.A.); (L.F.-G.); (M.L.); (G.B.)
- Study Group on Mechanisms of Action and Resistance to Antimicrobials (GEMARA) the Behalf of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC), 28003 Madrid, Spain; (J.-O.I.); (A.P.); (F.F.-C.)
- Spanish Network for Research in Infectious Diseases (REIPI), 41071 Seville, Spain
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Tandon H, Melarkode Vattekatte A, Srinivasan N, Sandhya S. Molecular and Structural Basis of Cross-Reactivity in M. tuberculosis Toxin-Antitoxin Systems. Toxins (Basel) 2020; 12:E481. [PMID: 32751054 PMCID: PMC7472061 DOI: 10.3390/toxins12080481] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/21/2020] [Accepted: 06/23/2020] [Indexed: 01/12/2023] Open
Abstract
Mycobacterium tuberculosis genome encodes over 80 toxin-antitoxin (TA) systems. While each toxin interacts with its cognate antitoxin, the abundance of TA systems presents an opportunity for potential non-cognate interactions. TA systems mediate manifold interactions to manage pathogenicity and stress response network of the cell and non-cognate interactions may play vital roles as well. To address if non-cognate and heterologous interactions are feasible and to understand the structural basis of their interactions, we have performed comprehensive computational analyses on the available 3D structures and generated structural models of paralogous M. tuberculosis VapBC and MazEF TA systems. For a majority of the TA systems, we show that non-cognate toxin-antitoxin interactions are structurally incompatible except for complexes like VapBC15 and VapBC11, which show similar interfaces and potential for cross-reactivity. For TA systems which have been experimentally shown earlier to disfavor non-cognate interactions, we demonstrate that they are structurally and stereo-chemically incompatible. For selected TA systems, our detailed structural analysis identifies specificity conferring residues. Thus, our work improves the current understanding of TA interfaces and generates a hypothesis based on congenial binding site, geometric complementarity, and chemical nature of interfaces. Overall, our work offers a structure-based explanation for non-cognate toxin-antitoxin interactions in M. tuberculosis.
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Affiliation(s)
- Himani Tandon
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India; (H.T.); (A.M.V.)
| | - Akhila Melarkode Vattekatte
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India; (H.T.); (A.M.V.)
- Biologie Intégrée du Globule Rouge UMR_S1134, INSERM, Université Paris, Université de la Réunion, Université des Antilles, F-75739 Paris, France
- Laboratoire d’Excellence GR-Ex, F-75739 Paris, France
- Faculté des Sciences et Technologies, Saint Denis Messag, F-97715 La Réunion, France
- Institut National de la Transfusion Sanguine (INTS), F-75739 Paris, France
| | - Narayanaswamy Srinivasan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India; (H.T.); (A.M.V.)
| | - Sankaran Sandhya
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India; (H.T.); (A.M.V.)
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Weaver K. The Fst/Ldr Family of Type I TA System Toxins: Potential Roles in Stress Response, Metabolism and Pathogenesis. Toxins (Basel) 2020; 12:toxins12080474. [PMID: 32722354 PMCID: PMC7472228 DOI: 10.3390/toxins12080474] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/20/2020] [Accepted: 07/23/2020] [Indexed: 12/27/2022] Open
Abstract
The parpAD1 locus was the first type I toxin-antitoxin (TA) system described in Gram-positive bacteria and was later determined to be the founding member of a widely distributed family of plasmid- and chromosomally encoded TA systems. Indeed, homology searches revealed that the toxin component, FstpAD1, is a member of the Fst/Ldr superfamily of peptide toxins found in both Gram-positive and Gram-negative bacteria. Regulation of the Fst and Ldr toxins is distinct in their respective Gram-positive and Gram-negative hosts, but the effects of ectopic over-expression are similar. While, the plasmid versions of these systems appear to play the canonical role of post-segregational killing stability mechanisms, the function of the chromosomal systems remains largely obscure. At least one member of the family has been suggested to play a role in pathogenesis in Staphylococcus aureus, while the regulation of several others appear to be tightly integrated with genes involved in sugar metabolism. After a brief discussion of the regulation and function of the foundational parpAD1 locus, this review will focus on the current information available on potential roles of the chromosomal homologs.
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Affiliation(s)
- Keith Weaver
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
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LeRoux M, Culviner PH, Liu YJ, Littlehale ML, Laub MT. Stress Can Induce Transcription of Toxin-Antitoxin Systems without Activating Toxin. Mol Cell 2020; 79:280-292.e8. [PMID: 32533919 PMCID: PMC7368831 DOI: 10.1016/j.molcel.2020.05.028] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 04/02/2020] [Accepted: 05/20/2020] [Indexed: 12/14/2022]
Abstract
Toxin-antitoxin (TA) systems are ubiquitous genetic elements in bacterial genomes, but their functions are controversial. Although they are frequently postulated to regulate cell growth following stress, few null phenotypes for TA systems have been reported. Here, we show that TA transcript levels can increase substantially in response to stress, but toxin is not liberated. We find that the growth of an Escherichia coli strain lacking ten TA systems encoding endoribonuclease toxins is not affected following exposure to six stresses that each trigger TA transcription. Additionally, using RNA sequencing, we find no evidence of mRNA cleavage following stress. Stress-induced transcription arises from antitoxin degradation and relief of transcriptional autoregulation. Importantly, although free antitoxin is readily degraded in vivo, antitoxin bound to toxin is protected from proteolysis, preventing release of active toxin. Thus, transcription is not a reliable marker of TA activity, and TA systems do not strongly promote survival following individual stresses.
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Affiliation(s)
- Michele LeRoux
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Peter H Culviner
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yue J Liu
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Megan L Littlehale
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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