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Carabias A, Camara-Wilpert S, Mestre MR, Lopéz-Méndez B, Hendriks IA, Zhao R, Pape T, Fuglsang A, Luk SHC, Nielsen ML, Pinilla-Redondo R, Montoya G. Retron-Eco1 assembles NAD +-hydrolyzing filaments that provide immunity against bacteriophages. Mol Cell 2024:S1097-2765(24)00394-0. [PMID: 38788717 DOI: 10.1016/j.molcel.2024.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 03/15/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024]
Abstract
Retrons are toxin-antitoxin systems protecting bacteria against bacteriophages via abortive infection. The Retron-Eco1 antitoxin is formed by a reverse transcriptase (RT) and a non-coding RNA (ncRNA)/multi-copy single-stranded DNA (msDNA) hybrid that neutralizes an uncharacterized toxic effector. Yet, the molecular mechanisms underlying phage defense remain unknown. Here, we show that the N-glycosidase effector, which belongs to the STIR superfamily, hydrolyzes NAD+ during infection. Cryoelectron microscopy (cryo-EM) analysis shows that the msDNA stabilizes a filament that cages the effector in a low-activity state in which ADPr, a NAD+ hydrolysis product, is covalently linked to the catalytic E106 residue. Mutations shortening the msDNA induce filament disassembly and the effector's toxicity, underscoring the msDNA role in immunity. Furthermore, we discovered a phage-encoded Retron-Eco1 inhibitor (U56) that binds ADPr, highlighting the intricate interplay between retron systems and phage evolution. Our work outlines the structural basis of Retron-Eco1 defense, uncovering ADPr's pivotal role in immunity.
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Affiliation(s)
- Arturo Carabias
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
| | - Sarah Camara-Wilpert
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mario Rodríguez Mestre
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Blanca Lopéz-Méndez
- Protein Purification and Characterization Facility, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ivo A Hendriks
- Proteomics Department, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Ruiliang Zhao
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Tillmann Pape
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; Core Facility for Integrated Microscopy (CFIM), Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anders Fuglsang
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Sean Hoi-Ching Luk
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Michael L Nielsen
- Proteomics Department, Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Rafael Pinilla-Redondo
- Section of Microbiology, Department of Biology, University of Copenhagen, 2100 Copenhagen, Denmark.
| | - Guillermo Montoya
- Structural Molecular Biology Group, Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark.
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2
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Hwang J, Ye DY, Jung GY, Jang S. Mobile genetic element-based gene editing and genome engineering: Recent advances and applications. Biotechnol Adv 2024; 72:108343. [PMID: 38521283 DOI: 10.1016/j.biotechadv.2024.108343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 03/14/2024] [Accepted: 03/16/2024] [Indexed: 03/25/2024]
Abstract
Genome engineering has revolutionized several scientific fields, ranging from biochemistry and fundamental research to therapeutic uses and crop development. Diverse engineering toolkits have been developed and used to effectively modify the genome sequences of organisms. However, there is a lack of extensive reviews on genome engineering technologies based on mobile genetic elements (MGEs), which induce genetic diversity within host cells by changing their locations in the genome. This review provides a comprehensive update on the versatility of MGEs as powerful genome engineering tools that offers efficient solutions to challenges associated with genome engineering. MGEs, including DNA transposons, retrotransposons, retrons, and CRISPR-associated transposons, offer various advantages, such as a broad host range, genome-wide mutagenesis, efficient large-size DNA integration, multiplexing capabilities, and in situ single-stranded DNA generation. We focused on the components, mechanisms, and features of each MGE-based tool to highlight their cellular applications. Finally, we discussed the current challenges of MGE-based genome engineering and provided insights into the evolving landscape of this transformative technology. In conclusion, the combination of genome engineering with MGE demonstrates remarkable potential for addressing various challenges and advancing the field of genetic manipulation, and promises to revolutionize our ability to engineer and understand the genomes of diverse organisms.
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Affiliation(s)
- Jaeseong Hwang
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Dae-Yeol Ye
- Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea
| | - Gyoo Yeol Jung
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea; Department of Chemical Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-gu, Pohang, Gyeongbuk 37673, Republic of Korea.
| | - Sungho Jang
- Department of Bioengineering and Nano-Bioengineering, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea; Division of Bioengineering, College of Life Sciences and Bioengineering, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea; Research Center for Bio Materials & Process Development, Incheon National University, 119 Academy-ro, Yeonsu-gu, Incheon 22012, Republic of Korea.
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3
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Kaur N, Pati PK. Retron Library Recombineering: Next Powerful Tool for Genome Editing after CRISPR/Cas. ACS Synth Biol 2024; 13:1019-1025. [PMID: 38480006 DOI: 10.1021/acssynbio.3c00667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Retron library recombineering (RLR) is a powerful tool in the field of genome editing that exceeds the scope and specificity of the CRISPR/Cas technique. In RLR, single-stranded DNA produced in vivo by harnessing the in-built potential of bacterial retrons is used for replication-dependent genome editing. RLR introduces several genomic variations at once, resulting in pooled and barcoded variant libraries, thus permitting multiplexed applications. Retron-generated RT-DNA has already shown promise for use in genome editing. Thus, this new tool will result in fresh, intriguing, and surprising developments in molecular biology and its juncture with other disciplines of research, including medicine, agriculture, and microbiology. In this review, we discuss the current state of this brand-new tool that could eventually boost genome editing research.
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Affiliation(s)
- Navdeep Kaur
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
| | - Pratap Kumar Pati
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, Punjab, India
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4
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Mayo-Muñoz D, Pinilla-Redondo R, Camara-Wilpert S, Birkholz N, Fineran PC. Inhibitors of bacterial immune systems: discovery, mechanisms and applications. Nat Rev Genet 2024; 25:237-254. [PMID: 38291236 DOI: 10.1038/s41576-023-00676-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2023] [Indexed: 02/01/2024]
Abstract
To contend with the diversity and ubiquity of bacteriophages and other mobile genetic elements, bacteria have developed an arsenal of immune defence mechanisms. Bacterial defences include CRISPR-Cas, restriction-modification and a growing list of mechanistically diverse systems, which constitute the bacterial 'immune system'. As a response, bacteriophages and mobile genetic elements have evolved direct and indirect mechanisms to circumvent or block bacterial defence pathways and ensure successful infection. Recent advances in methodological and computational approaches, as well as the increasing availability of genome sequences, have boosted the discovery of direct inhibitors of bacterial defence systems. In this Review, we discuss methods for the discovery of direct inhibitors, their diverse mechanisms of action and perspectives on their emerging applications in biotechnology and beyond.
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Affiliation(s)
- David Mayo-Muñoz
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Rafael Pinilla-Redondo
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Section of Microbiology, University of Copenhagen, Copenhagen, Denmark.
| | | | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
- Genetics Otago, University of Otago, Dunedin, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand.
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand.
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5
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Burke KA, Urick CD, Mzhavia N, Nikolich MP, Filippov AA. Correlation of Pseudomonas aeruginosa Phage Resistance with the Numbers and Types of Antiphage Systems. Int J Mol Sci 2024; 25:1424. [PMID: 38338703 PMCID: PMC10855318 DOI: 10.3390/ijms25031424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/18/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Phage therapeutics offer a potentially powerful approach for combating multidrug-resistant bacterial infections. However, to be effective, phage therapy must overcome existing and developing phage resistance. While phage cocktails can reduce this risk by targeting multiple receptors in a single therapeutic, bacteria have mechanisms of resistance beyond receptor modification. A rapidly growing body of knowledge describes a broad and varied arsenal of antiphage systems encoded by bacteria to counter phage infection. We sought to understand the types and frequencies of antiphage systems present in a highly diverse panel of Pseudomonas aeruginosa clinical isolates utilized to characterize novel antibacterials. Using the web-server tool PADLOC (prokaryotic antiviral defense locator), putative antiphage systems were identified in these P. aeruginosa clinical isolates based on sequence homology to a validated and curated catalog of known defense systems. Coupling this host bacterium sequence analysis with host range data for 70 phages, we observed a correlation between existing phage resistance and the presence of higher numbers of antiphage systems in bacterial genomes. We were also able to identify antiphage systems that were more prevalent in highly phage-resistant P. aeruginosa strains, suggesting their importance in conferring resistance.
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Affiliation(s)
| | | | | | | | - Andrey A. Filippov
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA; (K.A.B.); (C.D.U.); (N.M.); (M.P.N.)
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6
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Liu J, Cui L, Shi X, Yan J, Wang Y, Ni Y, He J, Wang X. Generation of DNAzyme in Bacterial Cells by a Bacterial Retron System. ACS Synth Biol 2024; 13:300-309. [PMID: 38171507 DOI: 10.1021/acssynbio.3c00509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
DNAzymes are catalytically active single-stranded DNAs in which DNAzyme 10-23 (Dz 10-23) consists of a catalytic core and a substrate-binding arm that reduces gene expression through sequence-specific mRNA cleavage. However, the in vivo application of Dz 10-23 depends on exogenous delivery, which leads to its inability to be synthesized and stabilized in vivo, thus limiting its application. As a unique reverse transcription system, the bacterial retron system can synthesize single-stranded DNA in vivo using ncRNA msr/msd as a template. The objective of this work is to reduce target gene expression using Dz 10-23 generated in vivo by the retron system. In this regard, we successfully generated Dz 10-23 by cloning the Dz 10-23 coding sequence into the retron msd gene and tested its ability to reduce specific gene expression by examining the mRNA levels of cfp encoding cyan fluorescence protein and other functional genes such as mreB and ftsZ. We found that Dz had different repressive effects when targeting different mRNA regions, and in general, the repressive effect was stronger when targeting downstream of mRNAs. Our results also suggested that the reduction effect was due to cleavage of the substrate mRNA by Dz 10-23 rather than the antisense effect of the substrate-binding arm. Therefore, this study not only provided a retron-based method for the intracellular generation of Dz 10-23 but also demonstrated that Dz 10-23 could reduce gene expression by cleaving target mRNAs in cells. We believe that this new strategy would have great potential in the regulation of gene expression.
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Affiliation(s)
- Jie Liu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Lina Cui
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xinyu Shi
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Jiahao Yan
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yifei Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yuyang Ni
- College of Life Sciences, Shangrao Normal University, Shangrao 334001, PR China
| | - Jin He
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xun Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China
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7
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Nicastro GG, Burroughs AM, Iyer L, Aravind L. Functionally comparable but evolutionarily distinct nucleotide-targeting effectors help identify conserved paradigms across diverse immune systems. Nucleic Acids Res 2023; 51:11479-11503. [PMID: 37889040 PMCID: PMC10681802 DOI: 10.1093/nar/gkad879] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
While nucleic acid-targeting effectors are known to be central to biological conflicts and anti-selfish element immunity, recent findings have revealed immune effectors that target their building blocks and the cellular energy currency-free nucleotides. Through comparative genomics and sequence-structure analysis, we identified several distinct effector domains, which we named Calcineurin-CE, HD-CE, and PRTase-CE. These domains, along with specific versions of the ParB and MazG domains, are widely present in diverse prokaryotic immune systems and are predicted to degrade nucleotides by targeting phosphate or glycosidic linkages. Our findings unveil multiple potential immune systems associated with at least 17 different functional themes featuring these effectors. Some of these systems sense modified DNA/nucleotides from phages or operate downstream of novel enzymes generating signaling nucleotides. We also uncovered a class of systems utilizing HSP90- and HSP70-related modules as analogs of STAND and GTPase domains that are coupled to these nucleotide-targeting- or proteolysis-induced complex-forming effectors. While widespread in bacteria, only a limited subset of nucleotide-targeting effectors was integrated into eukaryotic immune systems, suggesting barriers to interoperability across subcellular contexts. This work establishes nucleotide-degrading effectors as an emerging immune paradigm and traces their origins back to homologous domains in housekeeping systems.
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Affiliation(s)
- Gianlucca G Nicastro
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
| | - A Maxwell Burroughs
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
| | - Lakshminarayan M Iyer
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
| | - L Aravind
- Computational Biology Branch, National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, USA
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8
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Arkhipova IR, Yushenova IA. To Be Mobile or Not: The Variety of Reverse Transcriptases and Their Recruitment by Host Genomes. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1754-1762. [PMID: 38105196 DOI: 10.1134/s000629792311007x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 09/18/2023] [Accepted: 09/20/2023] [Indexed: 12/19/2023]
Abstract
Reverse transcriptases (RT), or RNA-dependent DNA polymerases, are unorthodox enzymes that originally added a new angle to the conventional view of the unidirectional flow of genetic information in the cell from DNA to RNA to protein. First discovered in vertebrate retroviruses, RTs were since re-discovered in most eukaryotes, bacteria, and archaea, spanning essentially all domains of life. For retroviruses, RTs provide the ability to copy the RNA genome into DNA for subsequent incorporation into the host genome, which is essential for their replication and survival. In cellular organisms, most RT sequences originate from retrotransposons, the type of self-replicating genetic elements that rely on reverse transcription to copy and paste their sequences into new genomic locations. Some retroelements, however, can undergo domestication, eventually becoming a valuable addition to the overall repertoire of cellular enzymes. They can be beneficial yet accessory, like the diversity-generating elements, or even essential, like the telomerase reverse transcriptases. Nowadays, ever-increasing numbers of domesticated RT-carrying genetic elements are being discovered. It may be argued that domesticated RTs and reverse transcription in general is more widespread in cellular organisms than previously thought, and that many important cellular functions, such as chromosome end maintenance, may evolve from an originally selfish process of converting RNA into DNA.
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Affiliation(s)
- Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
| | - Irina A Yushenova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA.
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9
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Akritidou K, Thurtle-Schmidt BH. OLD family nuclease function across diverse anti-phage defense systems. Front Microbiol 2023; 14:1268820. [PMID: 37840731 PMCID: PMC10568477 DOI: 10.3389/fmicb.2023.1268820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 09/14/2023] [Indexed: 10/17/2023] Open
Abstract
Bacteriophages constitute a ubiquitous threat to bacteria, and bacteria have evolved numerous anti-phage defense systems to protect themselves. These systems include well-studied phenomena such as restriction endonucleases and CRISPR, while emerging studies have identified many new anti-phage defense systems whose mechanisms are unknown or poorly understood. Some of these systems involve overcoming lysogenization defect (OLD) nucleases, a family of proteins comprising an ABC ATPase domain linked to a Toprim nuclease domain. Despite being discovered over 50 years ago, OLD nuclease function remained mysterious until recent biochemical, structural, and bioinformatic studies revealed that OLD nucleases protect bacteria by functioning in diverse anti-phage defense systems including the Gabija system and retrons. In this review we will highlight recent discoveries in OLD protein function and their involvement in multiple discrete anti-phage defense systems.
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10
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Dot EW, Thomason LC, Chappie JS. Everything OLD is new again: How structural, functional, and bioinformatic advances have redefined a neglected nuclease family. Mol Microbiol 2023; 120:122-140. [PMID: 37254295 DOI: 10.1111/mmi.15074] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 04/28/2023] [Accepted: 04/30/2023] [Indexed: 06/01/2023]
Abstract
Overcoming lysogenization defect (OLD) proteins are a conserved family of ATP-powered nucleases that function in anti-phage defense. Recent bioinformatic, genetic, and crystallographic studies have yielded new insights into the structure, function, and evolution of these enzymes. Here we review these developments and propose a new classification scheme to categorize OLD homologs that relies on gene neighborhoods, biochemical properties, domain organization, and catalytic machinery. This taxonomy reveals important similarities and differences between family members and provides a blueprint to contextualize future in vivo and in vitro findings. We also detail how OLD nucleases are related to PARIS and Septu anti-phage defense systems and discuss important mechanistic questions that remain unanswered.
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Affiliation(s)
- Elena Wanvig Dot
- Department of Molecular Medicine, Cornell University, Ithaca, New York, USA
| | - Lynn C Thomason
- Molecular Control and Genetics Section, RNA Biology Laboratory, National Cancer Institute at Frederick, National Institutes of Health, Frederick, Maryland, USA
| | - Joshua S Chappie
- Department of Molecular Medicine, Cornell University, Ithaca, New York, USA
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11
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González-Delgado A, Lopez SC, Rojas-Montero M, Fishman CB, Shipman SL. Simultaneous multi-site editing of individual genomes using retron arrays. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.549397. [PMID: 37503029 PMCID: PMC10370050 DOI: 10.1101/2023.07.17.549397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Our understanding of genomics is limited by the scale of our genomic technologies. While libraries of genomic manipulations scaffolded on CRISPR gRNAs have been transformative, these existing approaches are typically multiplexed across genomes. Yet much of the complexity of real genomes is encoded within a genome across sites. Unfortunately, building cells with multiple, non-adjacent precise mutations remains a laborious cycle of editing, isolating an edited cell, and editing again. Here, we describe a technology for precisely modifying multiple sites on a single genome simultaneously. This technology - termed a multitron - is built from a heavily modified retron, in which multiple donor-encoding msds are produced from a single transcript. The multitron architecture is compatible with both recombineering in prokaryotic cells and CRISPR editing in eukaryotic cells. We demonstrate applications for this approach in molecular recording, genetic element minimization, and metabolic engineering.
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Affiliation(s)
| | - Santiago C. Lopez
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Graduate Program in Bioengineering, University of California, San Francisco and Berkeley, CA, USA
| | | | - Chloe B. Fishman
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
| | - Seth L. Shipman
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
- Chan Zuckerberg Biohub – San Francisco, San Francisco, CA
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12
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Mayo-Muñoz D, Pinilla-Redondo R, Birkholz N, Fineran PC. A host of armor: Prokaryotic immune strategies against mobile genetic elements. Cell Rep 2023; 42:112672. [PMID: 37347666 DOI: 10.1016/j.celrep.2023.112672] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/22/2023] [Accepted: 06/02/2023] [Indexed: 06/24/2023] Open
Abstract
Prokaryotic adaptation is strongly influenced by the horizontal acquisition of beneficial traits via mobile genetic elements (MGEs), such as viruses/bacteriophages and plasmids. However, MGEs can also impose a fitness cost due to their often parasitic nature and differing evolutionary trajectories. In response, prokaryotes have evolved diverse immune mechanisms against MGEs. Recently, our understanding of the abundance and diversity of prokaryotic immune systems has greatly expanded. These defense systems can degrade the invading genetic material, inhibit genome replication, or trigger abortive infection, leading to population protection. In this review, we highlight these strategies, focusing on the most recent discoveries. The study of prokaryotic defenses not only sheds light on microbial evolution but also uncovers novel enzymatic activities with promising biotechnological applications.
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Affiliation(s)
- David Mayo-Muñoz
- Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Rafael Pinilla-Redondo
- Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Nils Birkholz
- Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Bioprotection Aotearoa, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Genetics Otago, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand; Bioprotection Aotearoa, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
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13
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Jia HJ, Jia PP, Yin S, Bu LK, Yang G, Pei DS. Engineering bacteriophages for enhanced host range and efficacy: insights from bacteriophage-bacteria interactions. Front Microbiol 2023; 14:1172635. [PMID: 37323893 PMCID: PMC10264812 DOI: 10.3389/fmicb.2023.1172635] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 05/10/2023] [Indexed: 06/17/2023] Open
Abstract
Bacteriophages, the most abundant organisms on earth, have the potential to address the rise of multidrug-resistant bacteria resulting from the overuse of antibiotics. However, their high specificity and limited host range can hinder their effectiveness. Phage engineering, through the use of gene editing techniques, offers a means to enhance the host range of bacteria, improve phage efficacy, and facilitate efficient cell-free production of phage drugs. To engineer phages effectively, it is necessary to understand the interaction between phages and host bacteria. Understanding the interaction between the receptor recognition protein of bacteriophages and host receptors can serve as a valuable guide for modifying or replacing these proteins, thereby altering the receptor range of the bacteriophage. Research and development focused on the CRISPR-Cas bacterial immune system against bacteriophage nucleic acids can provide the necessary tools to promote recombination and counter-selection in engineered bacteriophage programs. Additionally, studying the transcription and assembly functions of bacteriophages in host bacteria can facilitate the engineered assembly of bacteriophage genomes in non-host environments. This review highlights a comprehensive summary of phage engineering methods, including in-host and out-of-host engineering, and the use of high-throughput methods to understand their role. The main aim of these techniques is to harness the intricate interactions between bacteriophages and hosts to inform and guide the engineering of bacteriophages, particularly in the context of studying and manipulating the host range of bacteriophages. By employing advanced high-throughput methods to identify specific bacteriophage receptor recognition genes, and subsequently introducing modifications or performing gene swapping through in-host recombination or out-of-host synthesis, it becomes possible to strategically alter the host range of bacteriophages. This capability holds immense significance for leveraging bacteriophages as a promising therapeutic approach against antibiotic-resistant bacteria.
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Affiliation(s)
- Huang-Jie Jia
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - Pan-Pan Jia
- School of Public Health, Chongqing Medical University, Chongqing, China
| | - Supei Yin
- Urinary Nephropathy Center, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ling-Kang Bu
- College of Life Science, Henan Normal University, Xinxiang, China
| | - Guan Yang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, China
| | - De-Sheng Pei
- School of Public Health, Chongqing Medical University, Chongqing, China
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14
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Schwartzkopf CM, Robinson AJ, Ellenbecker M, Faith DR, Schmidt AK, Brooks DM, Lewerke L, Voronina E, Dandekar AA, Secor PR. Tripartite interactions between filamentous Pf4 bacteriophage, Pseudomonas aeruginosa, and bacterivorous nematodes. PLoS Pathog 2023; 19:e1010925. [PMID: 36800381 PMCID: PMC9980816 DOI: 10.1371/journal.ppat.1010925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/02/2023] [Accepted: 02/08/2023] [Indexed: 02/18/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa PAO1 is infected by the filamentous bacteriophage Pf4. Pf4 virions promote biofilm formation, protect bacteria from antibiotics, and modulate animal immune responses in ways that promote infection. Furthermore, strains cured of their Pf4 infection (ΔPf4) are less virulent in animal models of infection. Consistently, we find that strain ΔPf4 is less virulent in a Caenorhabditis elegans nematode infection model. However, our data indicate that PQS quorum sensing is activated and production of the pigment pyocyanin, a potent virulence factor, is enhanced in strain ΔPf4. The reduced virulence of ΔPf4 despite high levels of pyocyanin production may be explained by our finding that C. elegans mutants unable to sense bacterial pigments through the aryl hydrocarbon receptor are more susceptible to ΔPf4 infection compared to wild-type C. elegans. Collectively, our data support a model where suppression of quorum-regulated virulence factors by Pf4 allows P. aeruginosa to evade detection by innate host immune responses.
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Affiliation(s)
- Caleb M. Schwartzkopf
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Autumn J. Robinson
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Mary Ellenbecker
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Dominick R. Faith
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Amelia K. Schmidt
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Diane M. Brooks
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Lincoln Lewerke
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Ekaterina Voronina
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Ajai A. Dandekar
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Patrick R. Secor
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- * E-mail:
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15
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Millman A, Melamed S, Leavitt A, Doron S, Bernheim A, Hör J, Garb J, Bechon N, Brandis A, Lopatina A, Ofir G, Hochhauser D, Stokar-Avihail A, Tal N, Sharir S, Voichek M, Erez Z, Ferrer JLM, Dar D, Kacen A, Amitai G, Sorek R. An expanded arsenal of immune systems that protect bacteria from phages. Cell Host Microbe 2022; 30:1556-1569.e5. [DOI: 10.1016/j.chom.2022.09.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/15/2022] [Accepted: 09/28/2022] [Indexed: 01/16/2023]
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16
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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] [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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17
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Cryo-EM structures of Escherichia coli Ec86 retron complexes reveal architecture and defence mechanism. Nat Microbiol 2022; 7:1480-1489. [PMID: 35982312 DOI: 10.1038/s41564-022-01197-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 07/05/2022] [Indexed: 11/09/2022]
Abstract
First discovered in the 1980s, retrons are bacterial genetic elements consisting of a reverse transcriptase and a non-coding RNA (ncRNA). Retrons mediate antiphage defence in bacteria but their structure and defence mechanisms are unknown. Here, we investigate the Escherichia coli Ec86 retron and use cryo-electron microscopy to determine the structures of the Ec86 (3.1 Å) and cognate effector-bound Ec86 (2.5 Å) complexes. The Ec86 reverse transcriptase exhibits a characteristic right-hand-like fold consisting of finger, palm and thumb subdomains. Ec86 reverse transcriptase reverse-transcribes part of the ncRNA into satellite, multicopy single-stranded DNA (msDNA, a DNA-RNA hybrid) that we show wraps around the reverse transcriptase electropositive surface. In msDNA, both inverted repeats are present and the 3' sides of the DNA/RNA chains are close to the reverse transcriptase active site. The Ec86 effector adopts a two-lobe fold and directly binds reverse transcriptase and msDNA. These findings offer insights into the structure-function relationship of the retron-effector unit and provide a structural basis for the optimization of retron-based genome editing systems.
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18
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Mestre MR, Gao LA, Shah SA, López-Beltrán A, González-Delgado A, Martínez-Abarca F, Iranzo J, Redrejo-Rodríguez M, Zhang F, Toro N. UG/Abi: a highly diverse family of prokaryotic reverse transcriptases associated with defense functions. Nucleic Acids Res 2022; 50:6084-6101. [PMID: 35648479 PMCID: PMC9226505 DOI: 10.1093/nar/gkac467] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/11/2022] [Accepted: 05/17/2022] [Indexed: 11/20/2022] Open
Abstract
Reverse transcriptases (RTs) are enzymes capable of synthesizing DNA using RNA as a template. Within the last few years, a burst of research has led to the discovery of novel prokaryotic RTs with diverse antiviral properties, such as DRTs (Defense-associated RTs), which belong to the so-called group of unknown RTs (UG) and are closely related to the Abortive Infection system (Abi) RTs. In this work, we performed a systematic analysis of UG and Abi RTs, increasing the number of UG/Abi members up to 42 highly diverse groups, most of which are predicted to be functionally associated with other gene(s) or domain(s). Based on this information, we classified these systems into three major classes. In addition, we reveal that most of these groups are associated with defense functions and/or mobile genetic elements, and demonstrate the antiphage role of four novel groups. Besides, we highlight the presence of one of these systems in novel families of human gut viruses infecting members of the Bacteroidetes and Firmicutes phyla. This work lays the foundation for a comprehensive and unified understanding of these highly diverse RTs with enormous biotechnological potential.
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Affiliation(s)
- Mario Rodríguez Mestre
- Departamento de Bioquímica, Universidad Autónoma de Madrid (UAM) and Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain
| | - Linyi Alex Gao
- Howard Hughes Medical Institute, Cambridge, MA, USA.,Broad Institute of MIT and Harvard, Massachusetts Institute of Technology, Cambridge, MA, USA.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Society of Fellows, Harvard University, Cambridge, MA 02138, USA
| | - Shiraz A Shah
- Copenhagen Prospective Studies on Asthma in Childhood, Copenhagen University Hospital, Herlev-Gentofte, Ledreborg Allé 34, DK-2820 Gentofte, Denmark
| | - Adrián López-Beltrán
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Alejandro González-Delgado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Spain
| | - Francisco Martínez-Abarca
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Spain
| | - Jaime Iranzo
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain.,Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain
| | - Modesto Redrejo-Rodríguez
- Departamento de Bioquímica, Universidad Autónoma de Madrid (UAM) and Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), Madrid, Spain
| | - Feng Zhang
- Howard Hughes Medical Institute, Cambridge, MA, USA.,Broad Institute of MIT and Harvard, Massachusetts Institute of Technology, Cambridge, MA, USA.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nicolás Toro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Spain
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19
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Payne LJ, Meaden S, Mestre MR, Palmer C, Toro N, Fineran PC, Jackson SA. PADLOC: a web server for the identification of antiviral defence systems in microbial genomes. Nucleic Acids Res 2022; 50:W541-W550. [PMID: 35639517 PMCID: PMC9252829 DOI: 10.1093/nar/gkac400] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 04/24/2022] [Accepted: 05/05/2022] [Indexed: 12/16/2022] Open
Abstract
Most bacteria and archaea possess multiple antiviral defence systems that protect against infection by phages, archaeal viruses and mobile genetic elements. Our understanding of the diversity of defence systems has increased greatly in the last few years, and many more systems likely await discovery. To identify defence-related genes, we recently developed the Prokaryotic Antiviral Defence LOCator (PADLOC) bioinformatics tool. To increase the accessibility of PADLOC, we describe here the PADLOC web server (freely available at https://padloc.otago.ac.nz), allowing users to analyse whole genomes, metagenomic contigs, plasmids, phages and archaeal viruses. The web server includes a more than 5-fold increase in defence system types detected (since the first release) and expanded functionality enabling detection of CRISPR arrays and retron ncRNAs. Here, we provide user information such as input options, description of the multiple outputs, limitations and considerations for interpretation of the results, and guidance for subsequent analyses. The PADLOC web server also houses a precomputed database of the defence systems in > 230,000 RefSeq genomes. These data reveal two taxa, Campylobacterota and Spriochaetota, with unusual defence system diversity and abundance. Overall, the PADLOC web server provides a convenient and accessible resource for the detection of antiviral defence systems.
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Affiliation(s)
- Leighton J Payne
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Sean Meaden
- Biosciences, University of Exeter, Penryn, UK
| | | | - Chris Palmer
- Information Technology Services Research and Teaching Group, University of Otago, Dunedin, New Zealand
| | - Nicolás Toro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, Granada, Spain
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Genetics Otago, University of Otago, Dunedin, New Zealand.,Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Simon A Jackson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Genetics Otago, University of Otago, Dunedin, New Zealand.,Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
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20
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Rousset F, Depardieu F, Miele S, Dowding J, Laval AL, Lieberman E, Garry D, Rocha EPC, Bernheim A, Bikard D. Phages and their satellites encode hotspots of antiviral systems. Cell Host Microbe 2022; 30:740-753.e5. [PMID: 35316646 PMCID: PMC9122126 DOI: 10.1016/j.chom.2022.02.018] [Citation(s) in RCA: 95] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 01/27/2022] [Accepted: 02/23/2022] [Indexed: 11/18/2022]
Abstract
Bacteria carry diverse genetic systems to defend against viral infection, some of which are found within prophages where they inhibit competing viruses. Phage satellites pose additional pressures on phages by hijacking key viral elements to their own benefit. Here, we show that E. coli P2-like phages and their parasitic P4-like satellites carry hotspots of genetic variation containing reservoirs of anti-phage systems. We validate the activity of diverse systems and describe PARIS, an abortive infection system triggered by a phage-encoded anti-restriction protein. Antiviral hotspots participate in inter-viral competition and shape dynamics between the bacterial host, P2-like phages, and P4-like satellites. Notably, the anti-phage activity of satellites can benefit the helper phage during competition with virulent phages, turning a parasitic relationship into a mutualistic one. Anti-phage hotspots are present across distant species and constitute a substantial source of systems that participate in the competition between mobile genetic elements.
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Affiliation(s)
- François Rousset
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Synthetic Biology, 75015 Paris, France.
| | - Florence Depardieu
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Synthetic Biology, 75015 Paris, France
| | - Solange Miele
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Synthetic Biology, 75015 Paris, France
| | - Julien Dowding
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Synthetic Biology, 75015 Paris, France
| | - Anne-Laure Laval
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Synthetic Biology, 75015 Paris, France
| | | | | | - Eduardo P C Rocha
- Institut Pasteur, Université de Paris, CNRS UMR 3525, Microbial Evolutionary Genomics, 75015 Paris, France
| | - Aude Bernheim
- Université de Paris, INSERM, IAME, 75006 Paris, France
| | - David Bikard
- Institut Pasteur, Université de Paris, CNRS UMR 6047, Synthetic Biology, 75015 Paris, France.
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21
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Zeng Z, Chen Y, Pinilla-Redondo R, Shah SA, Zhao F, Wang C, Hu Z, Wu C, Zhang C, Whitaker RJ, She Q, Han W. A short prokaryotic Argonaute activates membrane effector to confer antiviral defense. Cell Host Microbe 2022; 30:930-943.e6. [PMID: 35594868 DOI: 10.1016/j.chom.2022.04.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 03/25/2022] [Accepted: 04/26/2022] [Indexed: 11/03/2022]
Abstract
Argonaute (Ago) proteins are widespread nucleic-acid-guided enzymes that recognize targets through complementary base pairing. Although, in eukaryotes, Agos are involved in RNA silencing, the functions of prokaryotic Agos (pAgos) remain largely unknown. In particular, a clade of truncated and catalytically inactive pAgos (short pAgos) lacks characterization. Here, we reveal that a short pAgo protein in the archaeon Sulfolobus islandicus, together with its two genetically associated proteins, Aga1 and Aga2, provide robust antiviral protection via abortive infection. Aga2 is a toxic transmembrane effector that binds anionic phospholipids via a basic pocket, resulting in membrane depolarization and cell killing. Ago and Aga1 form a stable complex that exhibits nucleic-acid-directed nucleic-acid-recognition ability and directly interacts with Aga2, pointing to an immune sensing mechanism. Together, our results highlight the cooperation between pAgos and their widespread associated proteins, suggesting an uncharted diversity of pAgo-derived immune systems.
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Affiliation(s)
- Zhifeng Zeng
- State Key Laboratory of Agricultural Microbiology and College of Life Sciences and Technology, Huazhong Agricultural University, 430070 Wuhan, China; Hubei Hongshan Laboratory, 430070 Wuhan, China
| | - Yu Chen
- State Key Laboratory of Agricultural Microbiology and College of Life Sciences and Technology, Huazhong Agricultural University, 430070 Wuhan, China; Hubei Hongshan Laboratory, 430070 Wuhan, China
| | - Rafael Pinilla-Redondo
- Section of Microbiology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark
| | - Shiraz A Shah
- Copenhagen Prospective Studies on Asthma in Childhood (COPSAC), Herlev and Gentofte Hospital, University of Copenhagen, Ledreborg Alle 34, 2820 Gentofte, Denmark
| | - Fen Zhao
- Hubei Hongshan Laboratory, 430070 Wuhan, China; National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, 430070 Wuhan, China
| | - Chen Wang
- Hubei Hongshan Laboratory, 430070 Wuhan, China; National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, 430070 Wuhan, China
| | - Zeyu Hu
- State Key Laboratory of Agricultural Microbiology and College of Life Sciences and Technology, Huazhong Agricultural University, 430070 Wuhan, China; Hubei Hongshan Laboratory, 430070 Wuhan, China
| | - Chang Wu
- State Key Laboratory of Agricultural Microbiology and College of Life Sciences and Technology, Huazhong Agricultural University, 430070 Wuhan, China; Hubei Hongshan Laboratory, 430070 Wuhan, China
| | - Changyi Zhang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, USA
| | - Rachel J Whitaker
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL 61801, USA
| | - Qunxin She
- CRISPR and Archaea Biology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Binhai Road 72, Jimo, 266237 Qingdao, China
| | - Wenyuan Han
- State Key Laboratory of Agricultural Microbiology and College of Life Sciences and Technology, Huazhong Agricultural University, 430070 Wuhan, China; Hubei Hongshan Laboratory, 430070 Wuhan, China.
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22
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Tesson F, Hervé A, Mordret E, Touchon M, d'Humières C, Cury J, Bernheim A. Systematic and quantitative view of the antiviral arsenal of prokaryotes. Nat Commun 2022; 13:2561. [PMID: 35538097 PMCID: PMC9090908 DOI: 10.1038/s41467-022-30269-9] [Citation(s) in RCA: 133] [Impact Index Per Article: 66.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/22/2022] [Indexed: 12/16/2022] Open
Abstract
Bacteria and archaea have developed multiple antiviral mechanisms, and genomic evidence indicates that several of these antiviral systems co-occur in the same strain. Here, we introduce DefenseFinder, a tool that automatically detects known antiviral systems in prokaryotic genomes. We use DefenseFinder to analyse 21000 fully sequenced prokaryotic genomes, and find that antiviral strategies vary drastically between phyla, species and strains. Variations in composition of antiviral systems correlate with genome size, viral threat, and lifestyle traits. DefenseFinder will facilitate large-scale genomic analysis of antiviral defense systems and the study of host-virus interactions in prokaryotes.
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Affiliation(s)
- Florian Tesson
- Université de Paris, IAME, UMR 1137, INSERM, Paris, France
- SEED, U1284, INSERM, Université de Paris, Paris, France
| | | | | | - Marie Touchon
- Institut Pasteur, Université de Paris, CNRS, UMR3525, Microbial Evolutionary Genomics, Paris, 75015, France
| | | | - Jean Cury
- SEED, U1284, INSERM, Université de Paris, Paris, France.
- Université Paris-Saclay, CNRS, INRIA, Laboratoire Interdisciplinaire des Sciences du Numérique, UMR, 9015, Orsay, France.
| | - Aude Bernheim
- Université de Paris, IAME, UMR 1137, INSERM, Paris, France.
- SEED, U1284, INSERM, Université de Paris, Paris, France.
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23
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Bujak K, Decewicz P, Kitowicz M, Radlinska M. Characterization of Three Novel Virulent Aeromonas Phages Provides Insights into the Diversity of the Autographiviridae Family. Viruses 2022; 14:1016. [PMID: 35632757 PMCID: PMC9145550 DOI: 10.3390/v14051016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/29/2022] [Accepted: 05/05/2022] [Indexed: 11/17/2022] Open
Abstract
In this study, we isolated and characterized three novel virulent Autographiviridae bacteriophages, vB_AspA_Bolek, vB_AspA_Lolek, and vB_AspA_Tola, which infect different Aeromonas strains. These three host-pathogen pairs were derived from the same sampling location-the arsenic-containing microbial mats of the Zloty Stok gold mine. Functional analysis showed they are psychrotolerant (4-25 °C), albeit with a much wider temperature range of propagation for the hosts (≤37 °C). Comparative genomic analyses revealed a high nucleotide and amino acid sequence similarity of vB_AspA_Bolek and vB_AspA_Lolek, with significant differences exclusively in the C-terminal region of their tail fibers, which might explain their host range discrimination. The protein-based phage network, together with a phylogenetic analysis of the marker proteins, allowed us to assign vB_AspA_Bolek and vB_AspA_Lolek to the Beijerinckvirinae and vB_AspA_Tola to the Colwellvirinae subfamilies, but as three novel species, due to their low nucleotide sequence coverage and identity with other known phage genomes. Global comparative analysis showed that the studied phages are also markedly different from most of the 24 Aeromonas autographiviruses known so far. Finally, this study provides in-depth insight into the diversity of the Autographiviridae phages and reveals genomic similarities between selected groups of this family as well as between autographiviruses and their relatives of other Caudoviricetes families.
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Affiliation(s)
| | | | | | - Monika Radlinska
- Department of Environmental Microbiology and Biotechnology, Faculty of Biology, Institute of Microbiology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland; (K.B.); (P.D.); (M.K.)
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24
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Paul BG, Eren AM. Eco-evolutionary significance of domesticated retroelements in microbial genomes. Mob DNA 2022; 13:6. [PMID: 35197094 PMCID: PMC8867640 DOI: 10.1186/s13100-022-00262-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/03/2022] [Indexed: 01/03/2023] Open
Abstract
Since the first discovery of reverse transcriptase in bacteria, and later in archaea, bacterial and archaeal retroelements have been defined by their common enzyme that coordinates diverse functions. Yet, evolutionary refinement has produced distinct retroelements across the tree of microbial life that are perhaps best described in terms of their programmed RNA—a compact sequence that preserves core information for a sophisticated mechanism. From this perspective, reverse transcriptase has been selected as the modular tool for carrying out nature’s instructions in various RNA templates. Beneficial retroelements—those that can provide a fitness advantage to their host—evolved to their extant forms in a wide array of microorganisms and their viruses, spanning nearly all habitats. Within each specialized retroelement class, several universal features seem to be shared across diverse taxa, while specific functional and mechanistic insights are based on only a few model retroelement systems from clinical isolates. Currently, little is known about the diversity of cellular functions and ecological significance of retroelements across different biomes. With increasing availability of isolate, metagenome-assembled, and single-amplified genomes, the taxonomic and functional breadth of prokaryotic retroelements is coming into clearer view. This review explores the recently characterized classes of beneficial, yet accessory retroelements of bacteria and archaea. We describe how these specialized mechanisms exploit a form of fixed mobility, whereby the retroelements do not appear to proliferate selfishly throughout the genome. Moreover, we discuss computational approaches for systematic identification of retroelements from vast sequence repositories and highlight recent discoveries in terms of their apparent distribution and ecological significance in nature. Lastly, we present a new perspective on the eco-evolutionary significance of these genetic elements in marine bacteria and demonstrate approaches that enable the characterization of their environmental diversity through metagenomics.
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Affiliation(s)
- Blair G Paul
- Marine Biological Laboratory, Josephine Bay Paul Center, Woods Hole, MA, USA.
| | - A Murat Eren
- Marine Biological Laboratory, Josephine Bay Paul Center, Woods Hole, MA, USA. .,Department of Medicine, University of Chicago, Chicago, IL, USA.
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25
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Palka C, Fishman CB, Bhattarai-Kline S, Myers SA, Shipman S. OUP accepted manuscript. Nucleic Acids Res 2022; 50:3490-3504. [PMID: 35293583 PMCID: PMC8989520 DOI: 10.1093/nar/gkac177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 11/14/2022] Open
Abstract
Retrons are bacterial retroelements that produce single-stranded, reverse-transcribed DNA (RT-DNA) that is a critical part of a newly discovered phage defense system. Short retron RT-DNAs are produced from larger, structured RNAs via a unique 2′-5′ initiation and a mechanism for precise termination that is not yet understood. Interestingly, retron reverse transcriptases (RTs) typically lack an RNase H domain and, therefore, depend on endogenous RNase H1 to remove RNA templates from RT-DNA. We find evidence for an expanded role of RNase H1 in the mechanism of RT-DNA termination, beyond the mere removal of RNA from RT-DNA:RNA hybrids. We show that endogenous RNase H1 determines the termination point of the retron RT-DNA, with differing effects across retron subtypes, and that these effects can be recapitulated using a reduced, in vitro system. We exclude mechanisms of termination that rely on steric effects of RNase H1 or RNA secondary structure and, instead, propose a model in which the tertiary structure of the single-stranded RT-DNA and remaining RNA template results in termination. Finally, we show that this mechanism affects cellular function, as retron-based phage defense is weaker in the absence of RNase H1.
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Affiliation(s)
| | | | | | | | - Seth L Shipman
- To whom correspondence should be addressed. Tel: +1 415 734 4058;
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26
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Sharifi F, Ye Y. Identification and classification of reverse transcriptases in bacterial genomes and metagenomes. Nucleic Acids Res 2021; 50:e29. [PMID: 34904653 PMCID: PMC8934634 DOI: 10.1093/nar/gkab1207] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 11/17/2021] [Accepted: 11/22/2021] [Indexed: 02/07/2023] Open
Abstract
Reverse transcriptases (RTs) are found in different systems including group II introns, Diversity Generating Retroelements (DGRs), retrons, CRISPR-Cas systems, and Abortive Infection (Abi) systems in prokaryotes. Different classes of RTs can play different roles, such as template switching and mobility in group II introns, spacer acquisition in CRISPR-Cas systems, mutagenic retrohoming in DGRs, programmed cell suicide in Abi systems, and recently discovered phage defense in retrons. While some classes of RTs have been studied extensively, others remain to be characterized. There is a lack of computational tools for identifying and characterizing various classes of RTs. In this study, we built a tool (called myRT) for identification and classification of prokaryotic RTs. In addition, our tool provides information about the genomic neighborhood of each RT, providing potential functional clues. We applied our tool to predict RTs in all complete and draft bacterial genomes, and created a collection that can be used for exploration of putative RTs and their associated protein domains. Application of myRT to metagenomes showed that gut metagenomes encode proportionally more RTs related to DGRs, outnumbering retron-related RTs, as compared to the collection of reference genomes. MyRT is both available as a standalone software (https://github.com/mgtools/myRT) and also through a website (https://omics.informatics.indiana.edu/myRT/).
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Affiliation(s)
- Fatemeh Sharifi
- Luddy School of Informatics, Computing, and Engineering, Indiana University, Bloomington, IN 47408, USA
| | - Yuzhen Ye
- Luddy School of Informatics, Computing, and Engineering, Indiana University, Bloomington, IN 47408, USA
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27
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González-Delgado A, Mestre MR, Martínez-Abarca F, Toro N. Prokaryotic reverse transcriptases: from retroelements to specialized defense systems. FEMS Microbiol Rev 2021; 45:fuab025. [PMID: 33983378 PMCID: PMC8632793 DOI: 10.1093/femsre/fuab025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 05/07/2021] [Indexed: 12/30/2022] Open
Abstract
Reverse transcriptases (RTs) catalyze the polymerization of DNA from an RNA template. These enzymes were first discovered in RNA tumor viruses in 1970, but it was not until 1989 that they were found in prokaryotes as a key component of retrons. Apart from RTs encoded by the 'selfish' mobile retroelements known as group II introns, prokaryotic RTs are extraordinarily diverse, but their function has remained elusive. However, recent studies have revealed that different lineages of prokaryotic RTs, including retrons, those associated with CRISPR-Cas systems, Abi-like RTs and other yet uncharacterized RTs, are key components of different lines of defense against phages and other mobile genetic elements. Prokaryotic RTs participate in various antiviral strategies, including abortive infection (Abi), in which the infected cell is induced to commit suicide to protect the host population, adaptive immunity, in which a memory of previous infection is used to build an efficient defense, and other as yet unidentified mechanisms. These prokaryotic enzymes are attracting considerable attention, both for use in cutting-edge technologies, such as genome editing, and as an emerging research topic. In this review, we discuss what is known about prokaryotic RTs, and the exciting evidence for their domestication from retroelements to create specialized defense systems.
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Affiliation(s)
- Alejandro González-Delgado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Mario Rodríguez Mestre
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, C/ Profesor Albareda 1, 18008 Granada, Spain
- Department of Biochemistry, Universidad Autónoma de Madrid and Instituto de Investigaciones Biomédicas “Alberto Sols”, CSIC-UAM, Madrid, Spain
| | - Francisco Martínez-Abarca
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, C/ Profesor Albareda 1, 18008 Granada, Spain
| | - Nicolás Toro
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Structure, Dynamics and Function of Rhizobacterial Genomes, Grupo de Ecología Genética de la Rizosfera, C/ Profesor Albareda 1, 18008 Granada, Spain
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28
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Payne LJ, Todeschini TC, Wu Y, Perry BJ, Ronson C, Fineran P, Nobrega F, Jackson S. Identification and classification of antiviral defence systems in bacteria and archaea with PADLOC reveals new system types. Nucleic Acids Res 2021; 49:10868-10878. [PMID: 34606606 PMCID: PMC8565338 DOI: 10.1093/nar/gkab883] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/13/2021] [Accepted: 09/17/2021] [Indexed: 11/14/2022] Open
Abstract
To provide protection against viral infection and limit the uptake of mobile genetic elements, bacteria and archaea have evolved many diverse defence systems. The discovery and application of CRISPR-Cas adaptive immune systems has spurred recent interest in the identification and classification of new types of defence systems. Many new defence systems have recently been reported but there is a lack of accessible tools available to identify homologs of these systems in different genomes. Here, we report the Prokaryotic Antiviral Defence LOCator (PADLOC), a flexible and scalable open-source tool for defence system identification. With PADLOC, defence system genes are identified using HMM-based homologue searches, followed by validation of system completeness using gene presence/absence and synteny criteria specified by customisable system classifications. We show that PADLOC identifies defence systems with high accuracy and sensitivity. Our modular approach to organising the HMMs and system classifications allows additional defence systems to be easily integrated into the PADLOC database. To demonstrate application of PADLOC to biological questions, we used PADLOC to identify six new subtypes of known defence systems and a putative novel defence system comprised of a helicase, methylase and ATPase. PADLOC is available as a standalone package (https://github.com/padlocbio/padloc) and as a webserver (https://padloc.otago.ac.nz).
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Affiliation(s)
- Leighton J Payne
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Thomas C Todeschini
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Yi Wu
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Benjamin J Perry
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Clive W Ronson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
| | - Franklin L Nobrega
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton, UK
| | - Simon A Jackson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Genetics Otago, University of Otago, Dunedin, New Zealand
- Bioprotection Aotearoa, University of Otago, Dunedin, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Otago, Dunedin, New Zealand
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29
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Genome Study of a Novel Virulent Phage vB_SspS_KASIA and Mu-like Prophages of Shewanella sp. M16 Provides Insights into the Genetic Diversity of the Shewanella Virome. Int J Mol Sci 2021; 22:ijms222011070. [PMID: 34681734 PMCID: PMC8541194 DOI: 10.3390/ijms222011070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 09/28/2021] [Accepted: 10/10/2021] [Indexed: 12/19/2022] Open
Abstract
Shewanella is a ubiquitous bacterial genus of aquatic ecosystems, and its bacteriophages are also isolated from aquatic environments (oceans, lakes, ice, and wastewater). In this study, the isolation and characterization of a novel virulent Shewanella phage vB_SspS_KASIA and the identification of three prophages of its host, Shewanella sp. M16, including a mitomycin-inducible Mu-like siphovirus, vB_SspS_MuM16-1, became the starting point for comparative analyses of phages infecting Shewanella spp. and the determination of their position among the known bacterial viruses. A similarity networking analysis revealed the high diversity of Shewanella phages in general, with vB_SspS_KASIA clustering exclusively with Colwellia phage 9A, with which it forms a single viral cluster composed of two separate viral subclusters. Furthermore, vB_SspS_MuM16-1 presented itself as being significantly different from the phages deposited in public databases, expanding the diversity of the known Mu-like phages and giving potential molecular markers for the identification of Mu-like prophages in bacterial genomes. Moreover, the functional analysis performed for vB_SspS_KASIA suggested that, despite the KASIA host, the M16 strain grows better in a rich medium and at 30 °C the phage replication cycle seems to be optimal in restrictive culture conditions mimicking their natural environment, the Zloty Stok gold and arsenic mine.
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Structural basis for template switching by a group II intron-encoded non-LTR-retroelement reverse transcriptase. J Biol Chem 2021; 297:100971. [PMID: 34280434 PMCID: PMC8363836 DOI: 10.1016/j.jbc.2021.100971] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/30/2021] [Accepted: 07/15/2021] [Indexed: 12/02/2022] Open
Abstract
Reverse transcriptases (RTs) can switch template strands during complementary DNA synthesis, enabling them to join discontinuous nucleic acid sequences. Template switching (TS) plays crucial roles in retroviral replication and recombination, is used for adapter addition in RNA-Seq, and may contribute to retroelement fitness by increasing evolutionary diversity and enabling continuous complementary DNA synthesis on damaged templates. Here, we determined an X-ray crystal structure of a TS complex of a group II intron RT bound simultaneously to an acceptor RNA and donor RNA template–DNA primer heteroduplex with a 1-nt 3′-DNA overhang. The structure showed that the 3′ end of the acceptor RNA binds in a pocket formed by an N-terminal extension present in non–long terminal repeat–retroelement RTs and the RT fingertips loop, with the 3′ nucleotide of the acceptor base paired to the 1-nt 3′-DNA overhang and its penultimate nucleotide base paired to the incoming dNTP at the RT active site. Analysis of structure-guided mutations identified amino acids that contribute to acceptor RNA binding and a phenylalanine residue near the RT active site that mediates nontemplated nucleotide addition. Mutation of the latter residue decreased multiple sequential template switches in RNA-Seq. Our results provide new insights into the mechanisms of TS and nontemplated nucleotide addition by RTs, suggest how these reactions could be improved for RNA-Seq, and reveal common structural features for TS by non–long terminal repeat–retroelement RTs and viral RNA–dependent RNA polymerases.
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