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Zhao X, Gao Y, Gong Q, Zhang K, Li S. Elucidating the Architectural dynamics of MuB filaments in bacteriophage Mu DNA transposition. Nat Commun 2024; 15:6445. [PMID: 39085263 PMCID: PMC11292022 DOI: 10.1038/s41467-024-50722-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 07/18/2024] [Indexed: 08/02/2024] Open
Abstract
MuB is a non-specific DNA-binding protein and AAA+ ATPase that significantly influences the DNA transposition process of bacteriophage Mu, especially in target DNA selection for transposition. While studies have established the ATP-dependent formation of MuB filament as pivotal to this process, the high-resolution structure of a full-length MuB protomer and the underlying molecular mechanisms governing its oligomerization remain elusive. Here, we use cryo-EM to obtain a 3.4-Å resolution structure of the ATP(+)-DNA(+)-MuB helical filament, which encapsulates the DNA substrate within its axial channel. The structure categorizes MuB within the initiator clade of the AAA+ protein family and precisely locates the ATP and DNA binding sites. Further investigation into the oligomeric states of MuB show the existence of various forms of the filament. These findings lead to a mechanistic model where MuB forms opposite helical filaments along the DNA, exposing potential target sites on the bare DNA and then recruiting MuA, which stimulates MuB's ATPase activity and disrupts the previously formed helical structure. When this happens, MuB generates larger ring structures and dissociates from the DNA.
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Affiliation(s)
- Xiaolong Zhao
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yongxiang Gao
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Qingguo Gong
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Kaiming Zhang
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Shanshan Li
- Department of Urology, The First Affiliated Hospital of USTC, MOE Key Laboratory for Cellular Dynamics, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
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2
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Evseev P, Lukianova A, Tarakanov R, Tokmakova A, Popova A, Kulikov E, Shneider M, Ignatov A, Miroshnikov K. Prophage-Derived Regions in Curtobacterium Genomes: Good Things, Small Packages. Int J Mol Sci 2023; 24:ijms24021586. [PMID: 36675099 PMCID: PMC9862828 DOI: 10.3390/ijms24021586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/15/2023] Open
Abstract
Curtobacterium is a genus of Gram-positive bacteria within the order Actinomycetales. Some Curtobacterium species (C. flaccumfaciens, C. plantarum) are harmful pathogens of agricultural crops such as soybean, dry beans, peas, sugar beet and beetroot, which occur throughout the world. Bacteriophages (bacterial viruses) are considered to be potential curative agents to control the spread of harmful bacteria. Temperate bacteriophages integrate their genomes into bacterial chromosomes (prophages), sometimes substantially influencing bacterial lifestyle and pathogenicity. About 200 publicly available genomes of Curtobacterium species, including environmental metagenomic sequences, were inspected for the presence of sequences of possible prophage origin using bioinformatic methods. The comparison of the search results with several ubiquitous bacterial groups showed the relatively low level of the presence of prophage traces in Curtobacterium genomes. Genomic and phylogenetic analyses were undertaken for the evaluation of the evolutionary and taxonomic positioning of predicted prophages. The analyses indicated the relatedness of Curtobacterium prophage-derived sequences with temperate actinophages of siphoviral morphology. In most cases, the predicted prophages can represent novel phage taxa not described previously. One of the predicted temperate phages was induced from the Curtobacterium genome. Bioinformatic analysis of the modelled proteins encoded in prophage-derived regions led to the discovery of some 100 putative glycopolymer-degrading enzymes that contained enzymatic domains with predicted cell-wall- and cell-envelope-degrading activity; these included glycosidases and peptidases. These proteins can be considered for the experimental design of new antibacterials against Curtobacterium phytopathogens.
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Affiliation(s)
- Peter Evseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
- Correspondence: (P.E.); (K.M.)
| | - Anna Lukianova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
| | - Rashit Tarakanov
- Department of Plant Protection, Russian State Agrarian University—Moscow Timiryazev Agricultural Academy, Timiryazevskaya Str. 49, 127434 Moscow, Russia
| | - Anna Tokmakova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology National Research University, Institutskiy Per, 9, 141701 Dolgoprudny, Russia
| | - Anastasia Popova
- State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia
| | - Eugene Kulikov
- School of Biological and Medical Physics, Moscow Institute of Physics and Technology National Research University, Institutskiy Per, 9, 141701 Dolgoprudny, Russia
- Research Center of Biotechnology, Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prosp. 60-letia Oktyabrya, 7-2, 117312 Moscow, Russia
| | - Mikhail Shneider
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
| | - Alexander Ignatov
- Agrobiotechnology Department, Agrarian and Technological Institute, RUDN University, Miklukho-Maklaya Str. 6, 117198 Moscow, Russia
| | - Konstantin Miroshnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
- Correspondence: (P.E.); (K.M.)
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3
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Khedkar S, Smyshlyaev G, Letunic I, Maistrenko OM, Coelho LP, Orakov A, Forslund SK, Hildebrand F, Luetge M, Schmidt TSB, Barabas O, Bork P. Landscape of mobile genetic elements and their antibiotic resistance cargo in prokaryotic genomes. Nucleic Acids Res 2022; 50:3155-3168. [PMID: 35323968 PMCID: PMC8989519 DOI: 10.1093/nar/gkac163] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/30/2022] [Accepted: 03/11/2022] [Indexed: 12/02/2022] Open
Abstract
Prokaryotic Mobile Genetic Elements (MGEs) such as transposons, integrons, phages and plasmids, play important roles in prokaryotic evolution and in the dispersal of cargo functions like antibiotic resistance. However, each of these MGE types is usually annotated and analysed individually, hampering a global understanding of phylogenetic and environmental patterns of MGE dispersal. We thus developed a computational framework that captures diverse MGE types, their cargos and MGE-mediated horizontal transfer events, using recombinases as ubiquitous MGE marker genes and pangenome information for MGE boundary estimation. Applied to ∼84k genomes with habitat annotation, we mapped 2.8 million MGE-specific recombinases to six operational MGE types, which together contain on average 13% of all the genes in a genome. Transposable elements (TEs) dominated across all taxa (∼1.7 million occurrences), outnumbering phages and phage-like elements (<0.4 million). We recorded numerous MGE-mediated horizontal transfer events across diverse phyla and habitats involving all MGE types, disentangled and quantified the extent of hitchhiking of TEs (17%) and integrons (63%) with other MGE categories, and established TEs as dominant carriers of antibiotic resistance genes. We integrated all these findings into a resource (proMGE.embl.de), which should facilitate future studies on the large mobile part of genomes and its horizontal dispersal.
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Affiliation(s)
- Supriya Khedkar
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Georgy Smyshlyaev
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany.,Department of Molecular Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Ivica Letunic
- Biobyte solutions GmbH, Bothestr 142, 69117 Heidelberg, Germany
| | - Oleksandr M Maistrenko
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Luis Pedro Coelho
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai 200433, China
| | - Askarbek Orakov
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Sofia K Forslund
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany.,Max Delbrück Centre for Molecular Medicine, Berlin, Germany.,Experimental and Clinical Research Center, Charité-Universitätsmedizin and Max-Delbrück Center, Berlin, Germany.,Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Falk Hildebrand
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Mechthild Luetge
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Thomas S B Schmidt
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany
| | - Orsolya Barabas
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany.,Department of Molecular Biology, University of Geneva, 1211 Geneva, Switzerland
| | - Peer Bork
- European Molecular Biology Laboratory, Structural and Computational Biology Unit, 69117 Heidelberg, Germany.,Max Delbrück Centre for Molecular Medicine, Berlin, Germany.,Department of Bioinformatics, Biocenter, University of Würzburg, Würzburg, Germany.,Yonsei Frontier Lab (YFL), Yonsei University, Seoul 03722, South Korea
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Abstract
A hallmark of retroviral replication is establishment of the proviral state, wherein a DNA copy of the viral RNA genome is stably incorporated into a host cell chromosome. Integrase is the viral enzyme responsible for the catalytic steps involved in this process, and integrase strand transfer inhibitors are widely used to treat people living with HIV. Over the past decade, a series of X-ray crystallography and cryogenic electron microscopy studies have revealed the structural basis of retroviral DNA integration. A variable number of integrase molecules congregate on viral DNA ends to assemble a conserved intasome core machine that facilitates integration. The structures additionally informed on the modes of integrase inhibitor action and the means by which HIV acquires drug resistance. Recent years have witnessed the development of allosteric integrase inhibitors, a highly promising class of small molecules that antagonize viral morphogenesis. In this Review, we explore recent insights into the organization and mechanism of the retroviral integration machinery and highlight open questions as well as new directions in the field.
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5
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Wangchuk J, Chatterjee A, Patil S, Madugula SK, Kondabagil K. The coevolution of large and small terminases of bacteriophages is a result of purifying selection leading to phenotypic stabilization. Virology 2021; 564:13-25. [PMID: 34598064 DOI: 10.1016/j.virol.2021.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/14/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
Genome packaging in many dsDNA phages requires a series of precisely coordinated actions of two phage-coded proteins, namely, large terminase (TerL) and small terminase (TerS) with DNA and ATP, and with each other. Despite the strict functional conservation, TerL and TerS homologs exhibit large sequence variations. We investigated the sequence variability across eight phage types and observed a coevolutionary framework wherein the genealogy of TerL homologs mirrored that of the corresponding TerS homologs. Furthermore, a high purifying selection observed (dN/dS«1) indicated strong structural constraints on both TerL and TerS, and identify coevolving residues in TerL and TerS of phage T4 and lambda. Using the highly coevolving (correlation coefficient of 0.99) TerL and TerS of phage N4, we show that their biochemical features are similar to the phylogenetically divergent phage λ terminases. We also demonstrate using the Surface Plasma Resonance (SPR) technique that phage N4 TerL transiently interacts with TerS.
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Affiliation(s)
- Jigme Wangchuk
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Anirvan Chatterjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Supriya Patil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Santhosh Kumar Madugula
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Kiran Kondabagil
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India.
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Mielinis P, Sukackaitė R, Serapinaitė A, Samoilovas F, Alzbutas G, Matjošaitis K, Lubys A. MuA-based Molecular Indexing for Rare Mutation Detection by Next-Generation Sequencing. J Mol Biol 2021; 433:167209. [PMID: 34419430 DOI: 10.1016/j.jmb.2021.167209] [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: 06/14/2021] [Revised: 08/12/2021] [Accepted: 08/12/2021] [Indexed: 12/12/2022]
Abstract
Detection of low-frequency mutations in cancer genomes or other heterogeneous cell populations requires high-fidelity sequencing. Molecular barcoding is one of the key technologies that enables the differentiation of true mutations from errors, which can be caused by sequencing or library preparation processes. However, current approaches where barcodes are introduced via primer extension or adaptor ligation do not utilize the full power of barcoding, due to complicated library preparation workflows and biases. Here we demonstrate the remarkable tolerance of MuA transposase to the presence of multiple replacements in transposon sequence, and explore this unique feature to engineer the MuA transposome complex with randomised nucleotides in 12 transposon positions, which can be introduced as a barcode into the target molecule after transposition event. We applied the approach of Unique MuA-based Molecular Indexing (UMAMI) to assess the power of rare mutation detection by shortgun sequencing on the Illumina platform. Our results show that UMAMI allows detection of rare mutations readily and reliably, and in this paper we report error rate values for the number of thermophilic DNA polymerases measured by using UMAMI.
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Affiliation(s)
- Paulius Mielinis
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania
| | - Rasa Sukackaitė
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania.
| | - Aistė Serapinaitė
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania
| | - Faustas Samoilovas
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania
| | - Gediminas Alzbutas
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania
| | - Karolis Matjošaitis
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania
| | - Arvydas Lubys
- Thermo Fisher Scientific Baltics UAB, V. A. Graičiūno 8, Vilnius LT-02241, Lithuania
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7
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Bacteriophage Technology and Modern Medicine. Antibiotics (Basel) 2021; 10:antibiotics10080999. [PMID: 34439049 PMCID: PMC8388951 DOI: 10.3390/antibiotics10080999] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 12/26/2022] Open
Abstract
The bacteriophage (or phage for short) has been used as an antibacterial agent for over a century but was abandoned in most countries after the discovery and broad use of antibiotics. The worldwide emergence and high prevalence of antimicrobial-resistant (AMR) bacteria have led to a revival of interest in the long-forgotten antibacterial therapy with phages (phage therapy) as an alternative approach to combatting AMR bacteria. The rapid progress recently made in molecular biology and genetic engineering has accelerated the generation of phage-related products with superior therapeutic potentials against bacterial infection. Nowadays, phage-based technology has been developed for many purposes, including those beyond the framework of antibacterial treatment, such as to suppress viruses by phages, gene therapy, vaccine development, etc. Here, we highlighted the current progress in phage engineering technology and its application in modern medicine.
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Characterization and Genome Analysis of a Novel Mu-like Phage VW-6B Isolated from the Napahai Plateau Wetland of China. Curr Microbiol 2020; 78:150-158. [PMID: 33150466 DOI: 10.1007/s00284-020-02277-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
Abstract
Although bacteriophages are more numerous and have smaller genomes than their bacterial hosts, relatively few have their genomes sequenced. Here, we isolated the Pseudomonas fluorescens bacteriophage from Napahai plateau wetland and performed de novo genome sequencing. Based on the previous biological characteristics and bioinformatics analysis, it was determined that VW-6B was a linear double-stranded DNA (dsDNA) phage with 35,306 bp, with 56.76% G+C content and 197 bp tandem repeats. The VW-6B genome contained 46 open-reading frames (ORFs), and no tRNA genes were found. Based on phage genome structure, sequence comparison, and collinear analysis, VW-6B should be classified into the family Siphoviridae and be considered as a member of a new species in the Mu-like phage. The newly isolated bacteriophage can specifically infect P. fluorescens, which further enriches the diversity of known bacteriophages and provides a basis for the subsequent research and application of bacteriophages.
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9
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Clokie MR, Blasdel BG, Demars BO, Sicheritz-Pontén T. Rethinking Phage Ecology by Rooting it Within an Established Plant Framework. PHAGE (NEW ROCHELLE, N.Y.) 2020; 1:121-136. [PMID: 36147824 PMCID: PMC9041459 DOI: 10.1089/phage.2020.0015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
Abstract
Despite the abundance and significance of bacteriophages to microbial ecosystems, no broad ecological frameworks exist within which to determine "bacteriophage types" that reflect their ecological strategies and ways in which they interact with bacterial cells. To address this, we repurposed the well-established Grime's triangular CSR framework, which classifies plants according to three axes: competitiveness (C), ability to tolerate stress (S), and capacity to cope with disturbance (R). This framework is distinguished from other accepted schemes, as it seeks to identify individual characteristics of plants to understand their biological strategies and roles within an ecosystem. Our repurposing of the CSR triangle is based on phage transcription and the observation that typically phages have three major distinguishable transcription phases: early, middle, and late. We hypothesize that the proportion of genes expressed in these phases reflects key information about the phage "ecological strategy," namely the C, S, and R strategies, allowing us to examine phages in a similar way to how plants are projected onto the triangle. In the "phage version" of this scheme, we suggest: (1) that some phages prioritize the early phase of transcription that shuts off host defense mechanisms, which reflects competitiveness; (2) other phages prioritize tuning resource management mechanisms in the cell such as nucleotide metabolism during their "mid" expression profile to tolerate stress; and (3) a further subset of phages (termed Ruderals) survive disturbance by investing significant resources into regeneration so they express a higher proportion of their genes during late infection. We examined 42 published phage transcriptomes and show that they fall into discrete CSR categories according to their expression profiles. We discuss these positions in the context of their biology, which is largely consistent with our predictions of specific phage characteristics. In this opinion article, we suggest a starting point to ascribe phages into different functional types and thus understand them in an ecological framework. We suggest that this may have far-reaching implications for the application of phages in therapy and their exploitation to manipulate bacterial communities. We invite further use of this framework via our online tool; www.PhageCSR.ml.
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Affiliation(s)
- Martha R.J. Clokie
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
- Address correspondence to: Martha R.J. Clokie, PhD, Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | | | | | - Thomas Sicheritz-Pontén
- Section for Evolutionary Genomics, The GLOBE Institute, University of Copenhagen, Copenhagen, Denmark
- Address correspondence to: Thomas Sicheritz Pontén, PhD, Section for Evolutionary Genomics, The GLOBE Institute, University of Copenhagen, Øster Farimagsgade 5, Bygning 7, Copenhagen 1353, Denmark
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10
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Rasila TS, Pulkkinen E, Kiljunen S, Haapa-Paananen S, Pajunen MI, Salminen A, Paulin L, Vihinen M, Rice PA, Savilahti H. Mu transpososome activity-profiling yields hyperactive MuA variants for highly efficient genetic and genome engineering. Nucleic Acids Res 2019; 46:4649-4661. [PMID: 29294068 PMCID: PMC5961161 DOI: 10.1093/nar/gkx1281] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/21/2017] [Indexed: 11/22/2022] Open
Abstract
The phage Mu DNA transposition system provides a versatile species non-specific tool for molecular biology, genetic engineering and genome modification applications. Mu transposition is catalyzed by MuA transposase, with DNA cleavage and integration reactions ultimately attaching the transposon DNA to target DNA. To improve the activity of the Mu DNA transposition machinery, we mutagenized MuA protein and screened for hyperactivity-causing substitutions using an in vivo assay. The individual activity-enhancing substitutions were mapped onto the MuA–DNA complex structure, containing a tetramer of MuA transposase, two Mu end segments and a target DNA. This analysis, combined with the varying effect of the mutations in different assays, implied that the mutations exert their effects in several ways, including optimizing protein–protein and protein–DNA contacts. Based on these insights, we engineered highly hyperactive versions of MuA, by combining several synergistically acting substitutions located in different subdomains of the protein. Purified hyperactive MuA variants are now ready for use as second-generation tools in a variety of Mu-based DNA transposition applications. These variants will also widen the scope of Mu-based gene transfer technologies toward medical applications such as human gene therapy. Moreover, the work provides a platform for further design of custom transposases.
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Affiliation(s)
- Tiina S Rasila
- Division of Genetics and Physiology, Department of Biology, FI-20014 University of Turku, Turku, Finland.,Institute of Biotechnology, Viikki Biocenter, P. O. Box 56, FI-00014 University of Helsinki, Helsinki, Finland
| | - Elsi Pulkkinen
- Division of Genetics and Physiology, Department of Biology, FI-20014 University of Turku, Turku, Finland
| | - Saija Kiljunen
- Division of Genetics and Physiology, Department of Biology, FI-20014 University of Turku, Turku, Finland
| | - Saija Haapa-Paananen
- Division of Genetics and Physiology, Department of Biology, FI-20014 University of Turku, Turku, Finland
| | - Maria I Pajunen
- Division of Biochemistry and Biotechnology, Department of Biosciences, FI-00014 University of Helsinki, Helsinki, Finland
| | - Anu Salminen
- Department of Biochemistry, FI-20014 University of Turku, Turku, Finland
| | - Lars Paulin
- Institute of Biotechnology, Viikki Biocenter, P. O. Box 56, FI-00014 University of Helsinki, Helsinki, Finland
| | - Mauno Vihinen
- Department of Experimental Medical Science, Lund University, SE-221 84, Lund, Sweden
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Harri Savilahti
- Division of Genetics and Physiology, Department of Biology, FI-20014 University of Turku, Turku, Finland.,Institute of Biotechnology, Viikki Biocenter, P. O. Box 56, FI-00014 University of Helsinki, Helsinki, Finland
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11
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Babakhani S, Oloomi M. Transposons: the agents of antibiotic resistance in bacteria. J Basic Microbiol 2018; 58:905-917. [PMID: 30113080 DOI: 10.1002/jobm.201800204] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/08/2018] [Accepted: 07/31/2018] [Indexed: 12/29/2022]
Abstract
Transposons are a group of mobile genetic elements that are defined as a DNA sequence. Transposons can jump into different places of the genome; for this reason, they are called jumping genes. However, some transposons are always kept at the insertion site in the genome. Most transposons are inactivated and as a result, cannot move. Transposons are divided into two main groups: retrotransposons (class І) and DNA transposons (class ІІ). Retrotransposons are often found in eukaryotes. DNA transposons can be found in both eukaryotes and prokaryotes. The bacterial transposons belong to the DNA transposons and the Tn family, which are usually the carrier of additional genes for antibiotic resistance. Transposons can transfer from a plasmid to other plasmids or from a DNA chromosome to plasmid and vice versa that cause the transmission of antibiotic resistance genes in bacteria. The treatment of bacterial infectious diseases is difficult because of existing antibiotic resistance that part of this antibiotic resistance is caused by transposons. Bacterial infectious diseases are responsible for the increasing rise in world mortality rate. In this review, transposons and their roles have been studied in bacterial antibiotic resistance, in detail.
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Affiliation(s)
- Sajad Babakhani
- Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mana Oloomi
- Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran
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12
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Vergnaud G, Midoux C, Blouin Y, Bourkaltseva M, Krylov V, Pourcel C. Transposition Behavior Revealed by High-Resolution Description of Pseudomonas Aeruginosa Saltovirus Integration Sites. Viruses 2018; 10:v10050245. [PMID: 29735891 PMCID: PMC5977238 DOI: 10.3390/v10050245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 04/27/2018] [Accepted: 05/04/2018] [Indexed: 01/08/2023] Open
Abstract
Transposable phages, also called saltoviruses, of which the Escherichia coli phage Mu is the reference, are temperate phages that multiply their genome through replicative transposition at multiple sites in their host chromosome. The viral genome is packaged together with host DNA at both ends. In the present work, genome sequencing of three Pseudomonas aeruginosa transposable phages, HW12, 2P1, and Ab30, incidentally gave us access to the location of thousands of replicative integration sites and revealed the existence of a variable number of hotspots. Taking advantage of deep sequencing, we then designed an experiment to study 13,000,000 transposon integration sites of bacteriophage Ab30. The investigation revealed the presence of 42 transposition hotspots adjacent to bacterial interspersed mosaic elements (BIME) accounting for 5% of all transposition sites. The rest of the sites appeared widely distributed with the exception of coldspots associated with low G-C content segments, including the putative O-antigen biosynthesis cluster. Surprisingly, 0.4% of the transposition events occurred in a copy of the phage genome itself, indicating that the previously described immunity against such events is slightly leaky. This observation allowed drawing an image of the phage chromosome supercoiling into four loops.
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Affiliation(s)
- Gilles Vergnaud
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
| | - Cédric Midoux
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
| | - Yann Blouin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
| | - Maria Bourkaltseva
- I. I. Mechnikov Research Institute for Vaccines & Sera, Moscow 105064, Russia.
| | - Victor Krylov
- I. I. Mechnikov Research Institute for Vaccines & Sera, Moscow 105064, Russia.
| | - Christine Pourcel
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette CEDEX, France.
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13
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Gorshkova NV, Lobanova JS, Tokmakova IL, Smirnov SV, Akhverdyan VZ, Krylov AA, Mashko SV. Mu-driven transposition of recombinant mini-Mu unit DNA in the Corynebacterium glutamicum chromosome. Appl Microbiol Biotechnol 2018; 102:2867-2884. [PMID: 29392386 PMCID: PMC5847225 DOI: 10.1007/s00253-018-8767-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/03/2018] [Accepted: 01/04/2018] [Indexed: 02/05/2023]
Abstract
A dual-component Mu-transposition system was modified for the integration/amplification of genes in Corynebacterium. The system consists of two types of plasmids: (i) a non-replicative integrative plasmid that contains the transposing mini-Mu(LR) unit bracketed by the L/R Mu ends or the mini-Mu(LER) unit, which additionally contains the enhancer element, E, and (ii) an integration helper plasmid that expresses the transposition factor genes for MuA and MuB. Efficient transposition in the C. glutamicum chromosome (≈ 2 × 10−4 per cell) occurred mainly through the replicative pathway via cointegrate formation followed by possible resolution. Optimizing the E location in the mini-Mu unit significantly increased the efficiency of Mu-driven intramolecular transposition–amplification in C. glutamicum as well as in gram-negative bacteria. The new C. glutamicum genome modification strategy that was developed allows the consequent independent integration/amplification/fixation of target genes at high copy numbers. After integration/amplification of the first mini-Mu(LER) unit in the C. glutamicum chromosome, the E-element, which is bracketed by lox-like sites, is excised by Cre-mediated fashion, thereby fixing the truncated mini-Mu(LR) unit in its position for the subsequent integration/amplification of new mini-Mu(LER) units. This strategy was demonstrated using the genes for the citrine and green fluorescent proteins, yECitrine and yEGFP, respectively.
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Affiliation(s)
- Natalya V Gorshkova
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545
| | - Juliya S Lobanova
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545
| | - Irina L Tokmakova
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545
| | - Sergey V Smirnov
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545
| | - Valerii Z Akhverdyan
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545
| | - Alexander A Krylov
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545
| | - Sergey V Mashko
- Ajinomoto-Genetika Research Institute, 1-st Dorozhny proezd, 1-1, Moscow, Russian Federation, 117545.
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14
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Abstract
Phage Mu is the paradigm of a growing family of bacteriophages that infect a wide range of bacterial species and replicate their genome by replicative transposition. This molecular process, which is used by other mobile genetic elements to move within genomes, involves the profound rearrangement of the host genome [chromosome(s) and plasmid(s)] and can be exploited for the genetic analysis of the host bacteria and the in vivo cloning of host genes. In this chapter we review Mu-derived constructs that optimize the phage as a series of genetic tools that could inspire the development of similarly efficient tools from other transposable phages for a large spectrum of bacteria.
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15
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A widespread family of polymorphic toxins encoded by temperate phages. BMC Biol 2017; 15:75. [PMID: 28851366 PMCID: PMC5576092 DOI: 10.1186/s12915-017-0415-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/07/2017] [Indexed: 12/21/2022] Open
Abstract
Background Polymorphic toxins (PTs) are multi-domain bacterial exotoxins belonging to distinct families that share common features in terms of domain organization. PTs are found in all major bacterial clades, including many toxic effectors of type V and type VI secretion systems. PTs modulate the dynamics of microbial communities by killing or inhibiting the growth of bacterial competitors lacking protective immunity proteins. Results In this work, we identified a novel widespread family of PTs, named MuF toxins, which were exclusively encoded within temperate phages and their prophages. By analyzing the predicted proteomes of 1845 bacteriophages and 2464 bacterial genomes, we found that MuF-containing proteins were frequently part of the DNA packaging module of tailed phages. Interestingly, MuF toxins were abundant in the human gut microbiome. Conclusions Our results uncovered the presence of the MuF toxin family in the temperate phages of Firmicutes. The MuF toxin family is likely to play an important role in the ecology of the human microbiota where pathogens and commensal species belonging to the Firmicutes are abundant. We propose that MuF toxins could be delivered by phages into host bacteria and either influence the lysogeny decision or serve as bacterial weapons by inhibiting the growth of competing bacteria. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0415-1) contains supplementary material, which is available to authorized users.
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16
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Fuller JR, Rice PA. Target DNA bending by the Mu transpososome promotes careful transposition and prevents its reversal. eLife 2017; 6. [PMID: 28177285 PMCID: PMC5357137 DOI: 10.7554/elife.21777] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 02/07/2017] [Indexed: 12/19/2022] Open
Abstract
The transposition of bacteriophage Mu serves as a model system for understanding DDE transposases and integrases. All available structures of these enzymes at the end of the transposition reaction, including Mu, exhibit significant bends in the transposition target site DNA. Here we use Mu to investigate the ramifications of target DNA bending on the transposition reaction. Enhancing the flexibility of the target DNA or prebending it increases its affinity for transpososomes by over an order of magnitude and increases the overall reaction rate. This and FRET confirm that flexibility is interrogated early during the interaction between the transposase and a potential target site, which may be how other DNA binding proteins can steer selection of advantageous target sites. We also find that the conformation of the target DNA after strand transfer is involved in preventing accidental catalysis of the reverse reaction, as conditions that destabilize this conformation also trigger reversal. DOI:http://dx.doi.org/10.7554/eLife.21777.001 Pieces of DNA called transposons can move or copy themselves around the genome. Some viruses – such as HIV and Mu (a virus that infects bacteria) – act as transposons to hide their DNA by inserting it into their host’s genome. Mu, HIV and many transposons all work in the same, somewhat unusual way. Like many chemical reactions, joining DNAs together needs a source of energy to make it happen, yet these viruses and transposons do not need high energy inputs to work. In addition, they do not look for a specific DNA sequence to insert their DNA into. This gives them the advantage of inserting copies of their DNA anywhere in the host’s genome, but also means that multiple copies might mistakenly insert into each other. Visualizations of the insertion process show that the DNA that the viruses insert their DNA into is always bent like a U-turn. Why does this bending occur? It may be that the bending helps the virus to choose where in the DNA to insert and acts as a way to power the chemical reaction that joins the DNA. To investigate this possibility, Fuller and Rice performed experiments using purified fragments of DNA and the enzyme from Mu that does the DNA joining chemistry. The results revealed that making the insertion site DNA easier to bend made the insertion much faster. Furthermore, a mutant enzyme that struggled to bend the DNA had trouble keeping the chemistry going, and so the viral DNA would accidentally pop back out after it was joined. Thus the insertion site DNA is like a spring: the enzyme puts a lot of energy into bending it, but once the viral DNA has been inserted that energy is released to power the reaction to completion. Fuller and Rice conclude that if other proteins were to pre-bend or otherwise make the DNA more flexible, this would tell the DNA-joining enzyme where to insert, which helps explain the roles of known targeting proteins for Mu and HIV. Further work is now needed to investigate whether these other targeting proteins exist for other viruses and transposons, and to identify them. DOI:http://dx.doi.org/10.7554/eLife.21777.002
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Affiliation(s)
- James R Fuller
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States
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17
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Abstract
DNA transposons are defined segments of DNA that are able to move from one genomic location to another. Movement is facilitated by one or more proteins, called the transposase, typically encoded by the mobile element itself. Here, we first provide an overview of the classification of such mobile elements in a variety of organisms. From a mechanistic perspective, we have focused on one particular group of DNA transposons that encode a transposase with a DD(E/D) catalytic domain that is topologically similar to RNase H. For these, a number of three-dimensional structures of transpososomes (transposase-nucleic acid complexes) are available, and we use these to describe the basics of their mechanisms. The DD(E/D) group, in addition to being the largest and most common among all DNA transposases, is the one whose members have been used for a wide variety of genomic applications. Therefore, a second focus of the article is to provide a nonexhaustive overview of transposon applications. Although several non-transposon-based approaches to site-directed genome modifications have emerged in the past decade, transposon-based applications are highly relevant when integration specificity is not sought. In fact, for many applications, the almost-perfect randomness and high frequency of integration make transposon-based approaches indispensable.
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Affiliation(s)
- Alison B. Hickman
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Fred Dyda
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
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18
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Software-based analysis of bacteriophage genomes, physical ends, and packaging strategies. BMC Genomics 2016; 17:679. [PMID: 27561606 PMCID: PMC5000459 DOI: 10.1186/s12864-016-3018-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Accepted: 08/13/2016] [Indexed: 11/17/2022] Open
Abstract
Background Phage genome analysis is a rapidly growing field. Recurrent obstacles include software access and usability, as well as genome sequences that vary in sequence orientation and/or start position. Here we describe modifications to the phage comparative genomics software program, Phamerator, provide public access to the code, and include instructions for creating custom Phamerator databases. We further report genomic analysis techniques to determine phage packaging strategies and identification of the physical ends of phage genomes. Results The original Phamerator code can be successfully modified and custom databases can be generated using the instructions we provide. Results of genome map comparisons within a custom database reveal obstacles in performing the comparisons if a published genome has an incorrect complementarity or an incorrect location of the first base of the genome, which are common issues in GenBank-downloaded sequence files. To address these issues, we review phage packaging strategies and provide results that demonstrate identification of the genome start location and orientation using raw sequencing data and software programs such as PAUSE and Consed to establish the location of the physical ends of the genome. These results include determination of exact direct terminal repeats (DTRs) or cohesive ends, or whether phages may use a headful packaging strategy. Phylogenetic analysis using ClustalO and phamily circles in Phamerator demonstrate that the large terminase gene can be used to identify the phage packaging strategy and thereby aide in identifying the physical ends of the genome. Conclusions Using available online code, the Phamerator program can be customized and utilized to generate databases with individually selected genomes. These databases can then provide fruitful information in the comparative analysis of phages. Researchers can identify packaging strategies and physical ends of phage genomes using raw data from high-throughput sequencing in conjunction with phylogenetic analyses of large terminase proteins and the use of custom Phamerator databases. We promote publication of phage genomes in an orientation consistent with the physical structure of the phage chromosome and provide guidance for determining this structure. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3018-2) contains supplementary material, which is available to authorized users.
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19
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Abstract
The integration of a DNA copy of the viral RNA genome into host chromatin is the defining step of retroviral replication. This enzymatic process is catalyzed by the virus-encoded integrase protein, which is conserved among retroviruses and LTR-retrotransposons. Retroviral integration proceeds via two integrase activities: 3'-processing of the viral DNA ends, followed by the strand transfer of the processed ends into host cell chromosomal DNA. Herein we review the molecular mechanism of retroviral DNA integration, with an emphasis on reaction chemistries and architectures of the nucleoprotein complexes involved. We additionally discuss the latest advances on anti-integrase drug development for the treatment of AIDS and the utility of integrating retroviral vectors in gene therapy applications.
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Affiliation(s)
- Paul Lesbats
- Clare Hall Laboratories, The Francis Crick Institute , Blanche Lane, South Mimms, EN6 3LD, U.K
| | - Alan N Engelman
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute and Department of Medicine, Harvard Medical School , 450 Brookline Avenue, Boston, Massachusetts 02215 United States
| | - Peter Cherepanov
- Clare Hall Laboratories, The Francis Crick Institute , Blanche Lane, South Mimms, EN6 3LD, U.K.,Imperial College London , St-Mary's Campus, Norfolk Place, London, W2 1PG, U.K
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20
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Abstract
Transposons of the Tn3 family form a widespread and remarkably homogeneous group of bacterial transposable elements in terms of transposition functions and an extremely versatile system for mediating gene reassortment and genomic plasticity owing to their modular organization. They have made major contributions to antimicrobial drug resistance dissemination or to endowing environmental bacteria with novel catabolic capacities. Here, we discuss the dynamic aspects inherent to the diversity and mosaic structure of Tn3-family transposons and their derivatives. We also provide an overview of current knowledge of the replicative transposition mechanism of the family, emphasizing most recent work aimed at understanding this mechanism at the biochemical level. Previous and recent data are put in perspective with those obtained for other transposable elements to build up a tentative model linking the activities of the Tn3-family transposase protein with the cellular process of DNA replication, suggesting new lines for further investigation. Finally, we summarize our current view of the DNA site-specific recombination mechanisms responsible for converting replicative transposition intermediates into final products, comparing paradigm systems using a serine recombinase with more recently characterized systems that use a tyrosine recombinase.
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21
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Abstract
Transposable phage Mu has played a major role in elucidating the mechanism of movement of mobile DNA elements. The high efficiency of Mu transposition has facilitated a detailed biochemical dissection of the reaction mechanism, as well as of protein and DNA elements that regulate transpososome assembly and function. The deduced phosphotransfer mechanism involves in-line orientation of metal ion-activated hydroxyl groups for nucleophilic attack on reactive diester bonds, a mechanism that appears to be used by all transposable elements examined to date. A crystal structure of the Mu transpososome is available. Mu differs from all other transposable elements in encoding unique adaptations that promote its viral lifestyle. These adaptations include multiple DNA (enhancer, SGS) and protein (MuB, HU, IHF) elements that enable efficient Mu end synapsis, efficient target capture, low target specificity, immunity to transposition near or into itself, and efficient mechanisms for recruiting host repair and replication machineries to resolve transposition intermediates. MuB has multiple functions, including target capture and immunity. The SGS element promotes gyrase-mediated Mu end synapsis, and the enhancer, aided by HU and IHF, participates in directing a unique topological architecture of the Mu synapse. The function of these DNA and protein elements is important during both lysogenic and lytic phases. Enhancer properties have been exploited in the design of mini-Mu vectors for genetic engineering. Mu ends assembled into active transpososomes have been delivered directly into bacterial, yeast, and human genomes, where they integrate efficiently, and may prove useful for gene therapy.
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22
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Feiner R, Argov T, Rabinovich L, Sigal N, Borovok I, Herskovits AA. A new perspective on lysogeny: prophages as active regulatory switches of bacteria. Nat Rev Microbiol 2016; 13:641-50. [PMID: 26373372 DOI: 10.1038/nrmicro3527] [Citation(s) in RCA: 269] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Unlike lytic phages, temperate phages that enter lysogeny maintain a long-term association with their bacterial host. In this context, mutually beneficial interactions can evolve that support efficient reproduction of both phages and bacteria. Temperate phages are integrated into the bacterial chromosome as large DNA insertions that can disrupt gene expression, and they may pose a fitness burden on the cell. However, they have also been shown to benefit their bacterial hosts by providing new functions in a bacterium-phage symbiotic interaction termed lysogenic conversion. In this Opinion article, we discuss another type of bacterium-phage interaction, active lysogeny, in which phages or phage-like elements are integrated into the bacterial chromosome within critical genes or operons and serve as switches that regulate bacterial genes via genome excision.
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Affiliation(s)
- Ron Feiner
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Tal Argov
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Lev Rabinovich
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Nadejda Sigal
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ilya Borovok
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anat A Herskovits
- Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv 69978, Israel
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23
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Yang J, Kong Y, Li X, Yang S. A novel transposable Mu-like prophage in Bacillus alcalophilus CGMCC 1.3604 (ATCC 27647). Virol Sin 2015; 30:63-5. [PMID: 25628219 DOI: 10.1007/s12250-014-3497-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Junjie Yang
- Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
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24
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The N-terminal domain of MuB protein has striking structural similarity to DNA-binding domains and mediates MuB filament-filament interactions. J Struct Biol 2015; 191:100-11. [PMID: 26169224 DOI: 10.1016/j.jsb.2015.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 11/21/2022]
Abstract
MuB is an ATP-dependent DNA-binding protein that regulates the activity of MuA transposase and delivers the target DNA for transposition of phage Mu. Mechanistic insight into MuB function is limited to its AAA+ ATPase module, which upon ATP binding assembles into helical filaments around the DNA. However, the structure and function of the flexible N-terminal domain (NTD) appended to the AAA+ module remains uncharacterized. Here we report the solution structure of MuB NTD determined by NMR spectroscopy. The structure reveals a compact domain formed by four α-helices connected by short loops, and confirms the presence of a helix-turn-helix motif. High structural similarity and sequence homology with λ repressor-like DNA-binding domains suggest a possible role of MuB NTD in DNA binding. We also demonstrate that the NTD directly mediates the ability of MuB to establish filament-filament interactions. These findings lead us to a model in which the NTD interacts with the AAA+ spirals and perhaps also with the DNA bound within the filament, favoring MuB polymerization and filament clustering. We propose that the MuB NTD-dependent filament interactions might be an effective mechanism to bridge distant DNA regions during Mu transposition.
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25
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Jang S, Harshey RM. Repair of transposable phage Mu DNA insertions begins only when the E. coli replisome collides with the transpososome. Mol Microbiol 2015; 97:746-58. [PMID: 25983038 DOI: 10.1111/mmi.13061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2015] [Indexed: 01/28/2023]
Abstract
We report a new cellular interaction between the infecting transposable phage Mu and the host Escherichia coli replication machinery during repair of Mu insertions, which involves filling-in of short target gaps on either side of the insertion, concomitant with degradation of extraneous long flanking DNA (FD) linked to Mu. Using the FD as a marker to follow repair, we find that after transposition into the chromosome, the unrepaired Mu is indefinitely stable until the replication fork arrives at the insertion site, whereupon the FD is rapidly degraded. When the fork runs into a Mu target gap, a double strand end (DSE) will result; we demonstrate fork-dependent DSEs proximal to Mu. These findings suggest that Pol III stalled at the transpososome is exploited for co-ordinated repair of both target gaps flanking Mu without replicating the intervening 37 kb of Mu, disassembling the stable transpososome in the process. This work is relevant to all transposable elements, including retroviral elements like HIV-1, which share with Mu the common problem of repair of their flanking target gaps.
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Affiliation(s)
- Sooin Jang
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
| | - Rasika M Harshey
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, 78712, USA
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26
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Affiliation(s)
- Ariane Toussaint
- Université Libre de Bruxelles; Génétique et physiologie bactérienne (LGPB) ; Campus de Gosselies - CP300 ; Charleroi (Gosselies), Belgium
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27
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Abstract
DNA transposases use a limited repertoire of structurally and mechanistically distinct nuclease domains to catalyze the DNA strand breaking and rejoining reactions that comprise DNA transposition. Here, we review the mechanisms of the four known types of transposition reactions catalyzed by (1) RNase H-like transposases (also known as DD(E/D) enzymes); (2) HUH single-stranded DNA transposases; (3) serine transposases; and (4) tyrosine transposases. The large body of accumulated biochemical and structural data, particularly for the RNase H-like transposases, has revealed not only the distinguishing features of each transposon family, but also some emerging themes that appear conserved across all families. The more-recently characterized single-stranded DNA transposases provide insight into how an ancient HUH domain fold has been adapted for transposition to accomplish excision and then site-specific integration. The serine and tyrosine transposases are structurally and mechanistically related to their cousins, the serine and tyrosine site-specific recombinases, but have to date been less intensively studied. These types of enzymes are particularly intriguing as in the context of site-specific recombination they require strict homology between recombining sites, yet for transposition can catalyze the joining of transposon ends to form an excised circle and then integration into a genomic site with much relaxed sequence specificity.
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Affiliation(s)
- Alison B Hickman
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Dr., Bethesda, MD 20892, USA
| | - Fred Dyda
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 5 Center Dr., Bethesda, MD 20892, USA
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28
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Hulo C, Masson P, Le Mercier P, Toussaint A. A structured annotation frame for the transposable phages: a new proposed family "Saltoviridae" within the Caudovirales. Virology 2014; 477:155-163. [PMID: 25500185 DOI: 10.1016/j.virol.2014.10.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 10/02/2014] [Accepted: 10/06/2014] [Indexed: 11/17/2022]
Abstract
Enterobacteriophage Mu is the best studied and paradigm member of the transposable phages. Mu-encoded proteins have been annotated in detail in UniProtKB and linked to a controlled vocabulary describing the various steps involved in the phage lytic and lysogenic cycles. Transposable phages are ubiquitous temperate bacterial viruses with a dsDNA linear genome. Twenty-six of them, that infect α, β and γ-proteobacteria, have been sequenced. Their conserved properties are described. Based on these characteristics, we propose a reorganization of the Caudovirales, to allow for the inclusion of a "Saltoviridae" family and two newly proposed subfamilies, the "Myosaltovirinae" and "Siphosaltovirinae". The latter could temporarily be included in the existing Myoviridae and Siphoviridae families.
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Affiliation(s)
- Chantal Hulo
- Swiss-Prot Group, Swiss Institute of Bioinformatics, Centre Médical Universitaire, CH-1211 Geneva 4, Switzerland
| | - Patrick Masson
- Swiss-Prot Group, Swiss Institute of Bioinformatics, Centre Médical Universitaire, CH-1211 Geneva 4, Switzerland
| | - Philippe Le Mercier
- Swiss-Prot Group, Swiss Institute of Bioinformatics, Centre Médical Universitaire, CH-1211 Geneva 4, Switzerland
| | - Ariane Toussaint
- Université Libre de Bruxelles, Génétique et Physiologie Bactérienne (LGPB), 12 rue des Professeurs Jeener et Brachet, 6041 Charleroi (Gosselies), Belgium.
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29
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Comparative genomic analysis shows that avian pathogenic Escherichia coli isolate IMT5155 (O2:K1:H5; ST complex 95, ST140) shares close relationship with ST95 APEC O1:K1 and human ExPEC O18:K1 strains. PLoS One 2014; 9:e112048. [PMID: 25397580 PMCID: PMC4232414 DOI: 10.1371/journal.pone.0112048] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 10/09/2014] [Indexed: 11/19/2022] Open
Abstract
Avian pathogenic E. coli and human extraintestinal pathogenic E. coli serotypes O1, O2 and O18 strains isolated from different hosts are generally located in phylogroup B2 and ST complex 95, and they share similar genetic characteristics and pathogenicity, with no or minimal host specificity. They are popular objects for the study of ExPEC genetic characteristics and pathogenesis in recent years. Here, we investigated the evolution and genetic blueprint of APEC pathotype by performing phylogenetic and comparative genome analysis of avian pathogenic E. coli strain IMT5155 (O2:K1:H5; ST complex 95, ST140) with other E. coli pathotypes. Phylogeny analyses indicated that IMT5155 has closest evolutionary relationship with APEC O1, IHE3034, and UTI89. Comparative genomic analysis showed that IMT5155 and APEC O1 shared significant genetic overlap/similarities with human ExPEC dominant O18:K1 strains (IHE3034 and UTI89). Furthermore, the unique PAI I5155 (GI-12) was identified and found to be conserved in APEC O2 serotype isolates. GI-7 and GI-16 encoding two typical T6SSs in IMT5155 might be useful markers for the identification of ExPEC dominant serotypes (O1, O2, and O18) strains. IMT5155 contained a ColV plasmid p1ColV5155, which defined the APEC pathotype. The distribution analysis of 10 sequenced ExPEC pan-genome virulence factors among 47 sequenced E. coli strains provided meaningful information for B2 APEC/ExPEC-specific virulence factors, including several adhesins, invasins, toxins, iron acquisition systems, and so on. The pathogenicity tests of IMT5155 and other APEC O1:K1 and O2:K1 serotypes strains (isolated in China) through four animal models showed that they were highly virulent for avian colisepticemia and able to cause septicemia and meningitis in neonatal rats, suggesting zoonotic potential of these APEC O1:K1 and O2:K1 isolates.
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30
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Mu transpososome and RecBCD nuclease collaborate in the repair of simple Mu insertions. Proc Natl Acad Sci U S A 2014; 111:14112-7. [PMID: 25197059 DOI: 10.1073/pnas.1407562111] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The genome of transposable phage Mu is packaged as a linear segment, flanked by several hundred base pairs of non-Mu DNA. The linear ends are held together and protected from nucleases by the phage N protein. After transposition into the Escherichia coli chromosome, the flanking DNA (FD) is degraded, and the 5-bp gaps left in the target are repaired to generate a simple Mu insertion. Our study provides insights into this repair pathway. The data suggest that the first event in repair is removal of the FD by the RecBCD exonuclease, whose entry past the N-protein block is licensed by the transpososome. In vitro experiments reveal that, when RecBCD is allowed entry into the FD, it degrades this DNA until it arrives at the transpososome, which presents a barrier for further RecBCD movement. RecBCD action is required for stimulating endonucleolytic cleavage within the transpososome-protected DNA, leaving 4-nt flanks outside both Mu ends. This end product of collaboration between the transpososome and RecBCD resembles the intermediate products of Tn7 and retroviral and retrotransposon transposition, and may hint at a common gap-repair mechanism in these diverse transposons.
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Toussaint A. Transposable Mu-like phages in Firmicutes: new instances of divergence generating retroelements. Res Microbiol 2013; 164:281-7. [DOI: 10.1016/j.resmic.2013.01.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 01/09/2013] [Indexed: 10/27/2022]
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