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Meier K, Thorkelsson SR, Durieux Trouilleton Q, Vogel D, Yu D, Kosinski J, Cusack S, Malet H, Grünewald K, Quemin ERJ, Rosenthal M. Structural and functional characterization of the Sin Nombre virus L protein. PLoS Pathog 2023; 19:e1011533. [PMID: 37549153 PMCID: PMC10406178 DOI: 10.1371/journal.ppat.1011533] [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: 02/10/2023] [Accepted: 07/04/2023] [Indexed: 08/09/2023] Open
Abstract
The Bunyavirales order is a large and diverse group of segmented negative-strand RNA viruses. Several virus families within this order contain important human pathogens, including Sin Nombre virus (SNV) of the Hantaviridae. Despite the high epidemic potential of bunyaviruses, specific medical countermeasures such as vaccines or antivirals are missing. The multifunctional ~250 kDa L protein of hantaviruses, amongst other functional domains, harbors the RNA-dependent RNA polymerase (RdRp) and an endonuclease and catalyzes transcription as well as replication of the viral RNA genome, making it a promising therapeutic target. The development of inhibitors targeting these key processes requires a profound understanding of the catalytic mechanisms. Here, we established expression and purification protocols of the full-length SNV L protein bearing the endonuclease mutation K124A. We applied different biochemical in vitro assays to provide an extensive characterization of the different enzymatic functions as well as the capacity of the hantavirus L protein to interact with the viral RNA. By using single-particle cryo-EM, we obtained a 3D model including the L protein core region containing the RdRp, in complex with the 5' promoter RNA. This first high-resolution model of a New World hantavirus L protein shows striking similarity to related bunyavirus L proteins. The interaction of the L protein with the 5' RNA observed in the structural model confirms our hypothesis of protein-RNA binding based on our biochemical data. Taken together, this study provides an excellent basis for future structural and functional studies on the hantavirus L protein and for the development of antiviral compounds.
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Affiliation(s)
- Kristina Meier
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Sigurdur R. Thorkelsson
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | | | - Dominik Vogel
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
| | - Dingquan Yu
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
| | - Jan Kosinski
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Stephen Cusack
- European Molecular Biology Laboratory (EMBL), Grenoble, France
| | - Hélène Malet
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
- Institut Universitaire de France (IUF), Paris, France
| | - Kay Grünewald
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
- University of Hamburg, Department of Chemistry, Hamburg, Germany
| | - Emmanuelle R. J. Quemin
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Leibniz Institute of Virology (LIV), Hamburg, Germany
| | - Maria Rosenthal
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Discovery Research ScreeningPort, Hamburg, Germany
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2
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Ueda K, Mizuuchi R, Ichihashi N. Emergence of linkage between cooperative RNA replicators encoding replication and metabolic enzymes through experimental evolution. PLoS Genet 2023; 19:e1010471. [PMID: 37540715 PMCID: PMC10431678 DOI: 10.1371/journal.pgen.1010471] [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: 10/12/2022] [Revised: 08/16/2023] [Accepted: 07/18/2023] [Indexed: 08/06/2023] Open
Abstract
The integration of individually replicating genes into a primitive chromosome is a key evolutionary transition in the development of life, allowing the simultaneous inheritance of genes. However, how this transition occurred is unclear because the extended size of primitive chromosomes replicate slower than unlinked genes. Theoretical studies have suggested that a primitive chromosome can evolve in the presence of cell-like compartments, as the physical linkage prevents the stochastic loss of essential genes upon division, but experimental support for this is lacking. Here, we demonstrate the evolution of a chromosome-like RNA from two cooperative RNA replicators encoding replication and metabolic enzymes. Through their long-term replication in cell-like compartments, linked RNAs emerged with the two cooperative RNAs connected end-to-end. The linked RNAs had different mutation patterns than the two unlinked RNAs, suggesting that they were maintained as partially distinct lineages in the population. Our results provide experimental evidence supporting the plausibility of the evolution of a primitive chromosome from unlinked gene fragments, an important step in the emergence of complex biological systems.
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Affiliation(s)
- Kensuke Ueda
- Department of Life Science, Graduate School of Arts and Science, the University of Tokyo, Meguro, Tokyo, Japan
| | - Ryo Mizuuchi
- Department of Electrical Engineering and Bioscience, Faculty of Science and Engineering, Waseda University, Shinjuku, Tokyo, Japan
- JST, FOREST, Kawaguchi, Saitama, Japan
| | - Norikazu Ichihashi
- Department of Life Science, Graduate School of Arts and Science, the University of Tokyo, Meguro, Tokyo, Japan
- Komaba Institute for Science, the University of Tokyo, Meguro, Tokyo, Japan
- Universal Biology Institute, the University of Tokyo, Meguro, Tokyo, Japan
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3
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Wells HL, Bonavita CM, Navarrete-Macias I, Vilchez B, Rasmussen AL, Anthony SJ. The coronavirus recombination pathway. Cell Host Microbe 2023; 31:874-889. [PMID: 37321171 PMCID: PMC10265781 DOI: 10.1016/j.chom.2023.05.003] [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: 04/03/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 06/17/2023]
Abstract
Recombination is thought to be a mechanism that facilitates cross-species transmission in coronaviruses, thus acting as a driver of coronavirus spillover and emergence. Despite its significance, the mechanism of recombination is poorly understood, limiting our potential to estimate the risk of novel recombinant coronaviruses emerging in the future. As a tool for understanding recombination, here, we outline a framework of the recombination pathway for coronaviruses. We review existing literature on coronavirus recombination, including comparisons of naturally observed recombinant genomes as well as in vitro experiments, and place the findings into the recombination pathway framework. We highlight gaps in our understanding of coronavirus recombination illustrated by the framework and outline how further experimental research is critical for disentangling the molecular mechanism of recombination from external environmental pressures. Finally, we describe how an increased understanding of the mechanism of recombination can inform pandemic predictive intelligence, with a retrospective emphasis on SARS-CoV-2.
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Affiliation(s)
- Heather L Wells
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, NY, USA; Department of Pathology, Microbiology, and Immunology, University of California Davis School of Veterinary Medicine, Davis, CA, USA.
| | - Cassandra M Bonavita
- Department of Pathology, Microbiology, and Immunology, University of California Davis School of Veterinary Medicine, Davis, CA, USA
| | - Isamara Navarrete-Macias
- Department of Pathology, Microbiology, and Immunology, University of California Davis School of Veterinary Medicine, Davis, CA, USA
| | - Blake Vilchez
- Department of Pathology, Microbiology, and Immunology, University of California Davis School of Veterinary Medicine, Davis, CA, USA
| | - Angela L Rasmussen
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, SK, Canada
| | - Simon J Anthony
- Department of Pathology, Microbiology, and Immunology, University of California Davis School of Veterinary Medicine, Davis, CA, USA.
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4
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Suardana IBK, Mahardika BK, Pharmawati M, Sudipa PH, Sari TK, Mahendra NB, Mahardika GN. Whole-Genome Comparison of Representatives of All Variants of SARS-CoV-2, Including Subvariant BA.2 and the GKA Clade. Adv Virol 2023; 2023:6476626. [PMID: 36938489 PMCID: PMC10019969 DOI: 10.1155/2023/6476626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 12/10/2022] [Accepted: 02/17/2023] [Indexed: 03/11/2023] Open
Abstract
Since its discovery at the end of 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly evolved into many variants, including the subvariant BA.2 and the GKA clade. Genomic clarification is needed for better management of the current pandemic as well as the possible reemergence of novel variants. The sequence of the reference genome Wuhan-Hu-1 and approximately 20 representatives of each variant were downloaded from GenBank and GISAID. Two representatives with no track of in-definitive nucleotides were selected. The sequences were aligned using muscle. The location of insertion/deletion (indel) in the genome was mapped following the open reading frame (ORF) of Wuhan-Hu-1. The phylogeny of the spike protein coding region was constructed using the maximum likelihood method. Amino acid substitutions in all ORFs were analyzed separately. There are two indel sites in ORF1AB, eight in spike, and one each in ORF3A, matrix (MA), nucleoprotein (NP), and the 3'-untranslated regions (3'UTR). Some indel sites and residues/substitutions are not unique, and some are variant-specific. The phylogeny shows that Omicron, Deltacron, and BA2 are clustered together and separated from other variants with 100% bootstrap support. In conclusion, whole-genome comparison of representatives of all variants revealed indel patterns that are specific to SARS-CoV-2 variants or subvariants. Polymorphic amino acid comparison across all coding regions also showed amino acid residues shared by specific groups of variants. Finally, the higher transmissibility of BA.2 might be due at least in part to the 48 nucleotide deletions in the 3'UTR, while the seem-to-be extinction of GKA clade is due to the lack of genetic advantages as a consequence of amino acid substitutions in various genes.
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Affiliation(s)
- Ida B. K. Suardana
- 1Virology Laboratory, The Faculty of Veterinary Medicine, Udayana University, Denpasar, Bali, Indonesia
| | - Bayu K. Mahardika
- 2The Animal Biomedical and Molecular Biology Laboratory, Udayana University, Jl. Sesetan-Markisa 6A, Denpasar 80223, Bali, Indonesia
| | - Made Pharmawati
- 3The Biology Study Program, The Faculty of Mathematic and Natural Science, Udayana University, Kampus Bukit Jimbaran, Badung, Bali, Indonesia
| | - Putu H. Sudipa
- 4Veterinary Bacteriology and Mycology Laboratory, The Faculty of Veterinary Medicine, Udayana University, Denpasar, Bali, Indonesia
| | - Tri K. Sari
- 1Virology Laboratory, The Faculty of Veterinary Medicine, Udayana University, Denpasar, Bali, Indonesia
| | - Nyoman B. Mahendra
- 5The Department of Obstetrics and Genecology, The Faculty of Medicine, Udayana University, Kuta Selatan, Bali, Indonesia
| | - Gusti N. Mahardika
- 1Virology Laboratory, The Faculty of Veterinary Medicine, Udayana University, Denpasar, Bali, Indonesia
- 2The Animal Biomedical and Molecular Biology Laboratory, Udayana University, Jl. Sesetan-Markisa 6A, Denpasar 80223, Bali, Indonesia
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5
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Mechanisms and Consequences of Genetic Variation in Hepatitis C Virus (HCV). Curr Top Microbiol Immunol 2023; 439:237-264. [PMID: 36592248 DOI: 10.1007/978-3-031-15640-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chronic infection with hepatitis C virus (HCV) is an important contributor to the global incidence of liver diseases, including liver cirrhosis and hepatocellular carcinoma. Although common for single-stranded RNA viruses, HCV displays a remarkable high level of genetic diversity, produced primarily by the error-prone viral polymerase and host immune pressure. The high genetic heterogeneity of HCV has led to the evolution of several distinct genotypes and subtypes, with important consequences for pathogenesis, and clinical outcomes. Genetic variability constitutes an evasion mechanism against immune suppression, allowing the virus to evolve epitope escape mutants that avoid immune recognition. Thus, heterogeneity and variability of the HCV genome represent a great hindrance for the development of vaccines against HCV. In addition, the high genetic plasticity of HCV allows the virus to rapidly develop antiviral resistance mutations, leading to treatment failure and potentially representing a major hindrance for the cure of chronic HCV patients. In this chapter, we will present the central role that genetic diversity has in the viral life cycle and epidemiology of HCV. Incorporation errors and recombination, both the result of HCV polymerase activity, represent the main mechanisms of HCV evolution. The molecular details of both mechanisms have been only partially clarified and will be presented in the following sections. Finally, we will discuss the major consequences of HCV genetic diversity, namely its capacity to rapidly evolve antiviral and immunological escape variants that represent an important limitation for clearance of acute HCV, for treatment of chronic hepatitis C and for broadly protective vaccines.
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6
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Fei Z, Jiao A, Xu M, Wu J, Wang Y, Yu J, Lu L, Jiang W, Zhu G, Sun W, Chen Z, Zhang Y, Ren S, Liu F, Zhang L. Genetic diversity and evolution of goose astrovirus in the east of China. Transbound Emerg Dis 2022; 69:e2059-e2072. [PMID: 35384346 DOI: 10.1111/tbed.14542] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/20/2022] [Accepted: 03/28/2022] [Indexed: 12/01/2022]
Abstract
Goose astrovirus (GAstV), an agent of fatal visceral gout in goslings, has been widely circulating in eastern China since 2017, but little is known about its genetic diversity and systematic evolution. In this study, we isolated and sequenced nine nearly full-length GAstV genomes and conducted comprehensive genetic diversity and evolutionary analysis and compared them with other reported GAstV sequences. Our results indicated that two genotypic species of GAstV were circulating in China, and GAstV-2 subgenotype II-c had arisen as the dominant genotype in Shandong province and across the whole country. Multiple alignment of GAstV amino acid sequences revealed several characteristic mutations in GAstV-2 II-c strains, as well as additional residues in the nine new isolates which varied over time. Phylogenetic analysis of three open reading frames demonstrated different evolutionary histories. Evidence of natural recombination was also detected in GAstV, with most of the recombination occurring in the GAstV-2 II-c subgenotype. Molecular adaptation analyses revealed that the evolution of GAstV was shaped by strong negative selection, although a number of amino acids, which potentially affect host infection and cell entry, were subjected to positive pressure. Overall, these findings improve our understanding of the epidemiology and evolution of GAstV and may help in the development of vaccines and diagnostics. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Zhiguo Fei
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Anqi Jiao
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Minli Xu
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Jiaqiang Wu
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China.,College of Life Sciences, Shandong Normal University, 88 Wenhua East Road, Jinan, Shandong, China
| | - Yu Wang
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Jiang Yu
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Lu Lu
- Emerging Economic Formats Research Institute, Shandong Management University, 3500 Dingxiang Road, Jinan, Shandong, China
| | - Wanchun Jiang
- College of Life Sciences and Food Engineering, Hebei University of Engineering, 199 Guangming South Street, Handan, Hebei, China
| | - Gaungwei Zhu
- Qilu Normal University, 2 Wenbo Road, Jinan, Shandong, China
| | - Wenbo Sun
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Zhi Chen
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Yuyu Zhang
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Sufang Ren
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Fei Liu
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
| | - Lin Zhang
- Shandong Key Laboratory of Disease Control and Breeding, Institute of Animal Science and Veterinary Medicine, Shandong Academy of Agricultural Science, 202 Gongye North Road, Jinan, Shandong, China
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7
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Quer J, Colomer-Castell S, Campos C, Andrés C, Piñana M, Cortese MF, González-Sánchez A, Garcia-Cehic D, Ibáñez M, Pumarola T, Rodríguez-Frías F, Antón A, Tabernero D. Next-Generation Sequencing for Confronting Virus Pandemics. Viruses 2022; 14:v14030600. [PMID: 35337007 PMCID: PMC8950049 DOI: 10.3390/v14030600] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 03/01/2022] [Accepted: 03/10/2022] [Indexed: 02/06/2023] Open
Abstract
Virus pandemics have happened, are happening and will happen again. In recent decades, the rate of zoonotic viral spillover into humans has accelerated, mirroring the expansion of our global footprint and travel network, including the expansion of viral vectors and the destruction of natural spaces, bringing humans closer to wild animals. Once viral cross-species transmission to humans occurs, transmission cannot be stopped by cement walls but by developing barriers based on knowledge that can prevent or reduce the effects of any pandemic. Controlling a local transmission affecting few individuals is more efficient that confronting a community outbreak in which infections cannot be traced. Genetic detection, identification, and characterization of infectious agents using next-generation sequencing (NGS) has been proven to be a powerful tool allowing for the development of fast PCR-based molecular assays, the rapid development of vaccines based on mRNA and DNA, the identification of outbreaks, transmission dynamics and spill-over events, the detection of new variants and treatment of vaccine resistance mutations, the development of direct-acting antiviral drugs, the discovery of relevant minority variants to improve knowledge of the viral life cycle, strengths and weaknesses, the potential for becoming dominant to take appropriate preventive measures, and the discovery of new routes of viral transmission.
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Affiliation(s)
- Josep Quer
- Liver Diseases-Viral Hepatitis, Liver Unit, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (S.C.-C.); (C.C.); (D.G.-C.); (M.I.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
- Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona (UAB), UAB Campus, Plaça Cívica, 08193 Bellaterra, Spain
- Correspondence: (J.Q.); (A.A.)
| | - Sergi Colomer-Castell
- Liver Diseases-Viral Hepatitis, Liver Unit, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (S.C.-C.); (C.C.); (D.G.-C.); (M.I.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
| | - Carolina Campos
- Liver Diseases-Viral Hepatitis, Liver Unit, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (S.C.-C.); (C.C.); (D.G.-C.); (M.I.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
| | - Cristina Andrés
- Microbiology Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (C.A.); (M.P.); (A.G.-S.); (T.P.)
| | - Maria Piñana
- Microbiology Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (C.A.); (M.P.); (A.G.-S.); (T.P.)
| | - Maria Francesca Cortese
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
- Clinical Biochemistry Research Group, Biochemistry Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - Alejandra González-Sánchez
- Microbiology Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (C.A.); (M.P.); (A.G.-S.); (T.P.)
| | - Damir Garcia-Cehic
- Liver Diseases-Viral Hepatitis, Liver Unit, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (S.C.-C.); (C.C.); (D.G.-C.); (M.I.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
| | - Marta Ibáñez
- Liver Diseases-Viral Hepatitis, Liver Unit, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (S.C.-C.); (C.C.); (D.G.-C.); (M.I.)
| | - Tomàs Pumarola
- Microbiology Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (C.A.); (M.P.); (A.G.-S.); (T.P.)
- Microbiology Department, Universitat Autònoma de Barcelona (UAB), UAB Campus, Plaça Cívica, 08193 Bellaterra, Spain
| | - Francisco Rodríguez-Frías
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
- Biochemistry and Molecular Biology Department, Universitat Autònoma de Barcelona (UAB), UAB Campus, Plaça Cívica, 08193 Bellaterra, Spain
- Clinical Biochemistry Research Group, Biochemistry Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - Andrés Antón
- Microbiology Department, Vall d’Hebron Institut of Research (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain; (C.A.); (M.P.); (A.G.-S.); (T.P.)
- Microbiology Department, Universitat Autònoma de Barcelona (UAB), UAB Campus, Plaça Cívica, 08193 Bellaterra, Spain
- Correspondence: (J.Q.); (A.A.)
| | - David Tabernero
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Av. Monforte de Lemos 3-5, 28029 Madrid, Spain; (M.F.C.); (F.R.-F.); (D.T.)
- Microbiology Departments, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain
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8
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Pimentel SC, Upton HE, Collins K. Separable structural requirements for cDNA synthesis, nontemplated extension, and template jumping by a non-LTR retroelement reverse transcriptase. J Biol Chem 2022; 298:101624. [PMID: 35065960 PMCID: PMC8857657 DOI: 10.1016/j.jbc.2022.101624] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 11/16/2022] Open
Abstract
Broad evolutionary expansion of polymerase families has enabled specialization of their activities for distinct cellular roles. In addition to template-complementary synthesis, many polymerases extend their duplex products by nontemplated nucleotide addition (NTA). This activity is exploited for laboratory strategies of cloning and sequencing nucleic acids and could have important biological function, although the latter has been challenging to test without separation-of-function mutations. Several retroelement and retroviral reverse transcriptases (RTs) support NTA and also template jumping, by which the RT performs continuous complementary DNA (cDNA) synthesis using physically separate templates. Previous studies that aimed to dissect the relationship between NTA and template jumping leave open questions about structural requirements for each activity and their interdependence. Here, we characterize the structural requirements for cDNA synthesis, NTA, template jumping, and the unique terminal transferase activity of Bombyx mori R2 non-long terminal repeat retroelement RT. With sequence alignments and structure modeling to guide mutagenesis, we generated enzyme variants across motifs generally conserved or specific to RT subgroups. Enzyme variants had diverse NTA profiles not correlated with other changes in cDNA synthesis activity or template jumping. Using these enzyme variants and panels of activity assay conditions, we show that template jumping requires NTA. However, template jumping by NTA-deficient enzymes can be rescued using primer duplex with a specific length of 3′ overhang. Our findings clarify the relationship between NTA and template jumping as well as additional activities of non-long terminal repeat RTs, with implications for the specialization of RT biological functions and laboratory applications.
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Affiliation(s)
- Sydney C Pimentel
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA
| | - Heather E Upton
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, California, USA.
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9
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Garushyants SK, Rogozin IB, Koonin EV. Template switching and duplications in SARS-CoV-2 genomes give rise to insertion variants that merit monitoring. Commun Biol 2021; 4:1343. [PMID: 34848826 PMCID: PMC8632935 DOI: 10.1038/s42003-021-02858-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 11/01/2021] [Indexed: 12/29/2022] Open
Abstract
The appearance of multiple new SARS-CoV-2 variants during the COVID-19 pandemic is a matter of grave concern. Some of these variants, such as B.1.617.2, B.1.1.7, and B.1.351, manifest higher infectivity and virulence than the earlier SARS-CoV-2 variants, with potential dramatic effects on the course of the pandemic. So far, analysis of new SARS-CoV-2 variants focused primarily on nucleotide substitutions and short deletions that are readily identifiable by comparison to consensus genome sequences. In contrast, insertions have largely escaped the attention of researchers although the furin site insert in the Spike (S) protein is thought to be a determinant of SARS-CoV-2 virulence. Here, we identify 346 unique inserts of different lengths in SARS-CoV-2 genomes and present evidence that these inserts reflect actual virus variance rather than sequencing artifacts. Two principal mechanisms appear to account for the inserts in the SARS-CoV-2 genomes, polymerase slippage and template switch that might be associated with the synthesis of subgenomic RNAs. At least three inserts in the N-terminal domain of the S protein are predicted to lead to escape from neutralizing antibodies, whereas other inserts might result in escape from T-cell immunity. Thus, inserts in the S protein can affect its antigenic properties and merit monitoring.
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Affiliation(s)
- Sofya K Garushyants
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Igor B Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA.
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10
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Garushyants SK, Rogozin IB, Koonin EV. Insertions in SARS-CoV-2 genome caused by template switch and duplications give rise to new variants that merit monitoring. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.04.23.441209. [PMID: 33907754 PMCID: PMC8077628 DOI: 10.1101/2021.04.23.441209] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The appearance of multiple new SARS-CoV-2 variants during the winter of 2020-2021 is a matter of grave concern. Some of these new variants, such as B.1.617.2, B.1.1.7, and B.1.351, manifest higher infectivity and virulence than the earlier SARS-CoV-2 variants, with potential dramatic effects on the course of the COVID-19 pandemic. So far, analysis of new SARS-CoV-2 variants focused primarily on point nucleotide substitutions and short deletions that are readily identifiable by comparison to consensus genome sequences. In contrast, insertions have largely escaped the attention of researchers although the furin site insert in the spike protein is thought to be a determinant of SARS-CoV-2 virulence and other inserts might have contributed to coronavirus pathogenicity as well. Here, we investigate insertions in SARS-CoV-2 genomes and identify 347 unique inserts of different lengths. We present evidence that these inserts reflect actual virus variance rather than sequencing errors. Two principal mechanisms appear to account for the inserts in the SARS-CoV-2 genomes, polymerase slippage and template switch that might be associated with the synthesis of subgenomic RNAs. We show that inserts in the Spike glycoprotein can affect its antigenic properties and thus merit monitoring. At least, three inserts in the N-terminal domain of the Spike (ins245IME, ins246DSWG, and ins248SSLT) that were first detected in 2021 are predicted to lead to escape from neutralizing antibodies, whereas other inserts might result in escape from T-cell immunity.
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Affiliation(s)
- Sofya K. Garushyants
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Igor B. Rogozin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
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11
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Shrestha N, Bujarski JJ. Long Noncoding RNAs in Plant Viroids and Viruses: A Review. Pathogens 2020; 9:E765. [PMID: 32961969 PMCID: PMC7559573 DOI: 10.3390/pathogens9090765] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/15/2020] [Accepted: 09/16/2020] [Indexed: 12/11/2022] Open
Abstract
Infectious long-noncoding (lnc) RNAs related to plants can be of both viral and non-viral origin. Viroids are infectious plant lncRNAs that are not related to viruses and carry the circular, single-stranded, non-coding RNAs that replicate with host enzymatic activities via a rolling circle mechanism. Viroids interact with host processes in complex ways, emerging as one of the most productive tools for studying the functions of lncRNAs. Defective (D) RNAs, another category of lnc RNAs, are found in a variety of plant RNA viruses, most of which are noncoding. These are derived from and are replicated by the helper virus. D RNA-virus interactions evolve into mutually beneficial combinations, enhancing virus fitness via competitive advantages of moderated symptoms. Yet the satellite RNAs are single-stranded and include either large linear protein-coding ss RNAs, small linear ss RNAs, or small circular ss RNAs (virusoids). The satellite RNAs lack sequence homology to the helper virus, but unlike viroids need a helper virus to replicate and encapsidate. They can attenuate symptoms via RNA silencing and enhancement of host defense, but some can be lethal as RNA silencing suppressor antagonists. Moreover, selected viruses produce lncRNAs by incomplete degradation of genomic RNAs. They do not replicate but may impact viral infection, gene regulation, and cellular functions. Finally, the host plant lncRNAs can also contribute during plant-virus interactions, inducing plant defense and the regulation of gene expression, often in conjunction with micro and/or circRNAs.
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Affiliation(s)
- Nipin Shrestha
- Department of Biological Sciences and Plant Molecular and Bioinformatics Center, Northern Illinois University, DeKalb, IL 60115, USA
| | - Józef J. Bujarski
- Department of Biological Sciences and Plant Molecular and Bioinformatics Center, Northern Illinois University, DeKalb, IL 60115, USA
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12
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Zhang W, Wang R, Liang J, Zhao N, Li G, Gao Q, Su S. Epidemiology, genetic diversity and evolution of canine astrovirus. Transbound Emerg Dis 2020; 67:2901-2910. [PMID: 32946195 DOI: 10.1111/tbed.13663] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/30/2020] [Accepted: 05/30/2020] [Indexed: 01/19/2023]
Abstract
Astroviruses (AstVs) are major causative agents of gastroenteritis in children and have been reported in many species. Canine astrovirus (CaAstV), as an enteric pathogen, has been widely detected worldwide, but little is known about their genetic diversity and evolution, partly owing to a lack of genomic data. Here, we sequenced 12 nearly full-length CaAstV genomes to address the gap in knowledge. We found 14 (13.2%) and 7 (3.35%) CaAstV-positive samples from pet dogs with and without diarrhoea, respectively. Co-infections were with co-infection with Torque teno canis virus (TTCaV) reported for the first time. Phylogenetic analysis of the ORF2 gene revealed four major lineages. In particular, lineage 4 might have evolved from a recombinant virus from lineage 2 and lineage 3. The strains sequenced here clustered with lineages 2, 3 and 4 in contrast with other Chinese strains identified previously that clustered with lineages 2 and 4. Amino acid sequence alignment within lineage revealed intralineage amino acid diversity and that the type of epidemic strains within lineages changes over time. Three amino acids substitutions located in predicted B-cell epitopes, which might be involved escape of host immunity. Moreover, frequent inter-clade ORF2 gene recombinants were identified. The identification of individual recombination events and a recombinant lineage indicated that recombination plays a crucial role in CaAstV genetic evolution and diversity by generating divergent viruses. Moreover, phylogenetic analysis of ORF1b, the most conserved gene of astrovirus, revealed a close relationship between CaAstV and California sea lion astroviruses. Overall, we report detailed information on the genetic evolution and diversity of CaAstV, which indicates that CaAstV may pose challenges for diagnostics and future control strategies.
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Affiliation(s)
- Wenyan Zhang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Ruyi Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Jiawei Liang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Naiyu Zhao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Gairu Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Qi Gao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Shuo Su
- MOE Joint International Research Laboratory of Animal Health and Food Safety, Jiangsu Engineering 1. Laboratory of Animal Immunology, Institute of Immunology and College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
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13
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14
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Kovalev N, Pogany J, Nagy PD. Interviral Recombination between Plant, Insect, and Fungal RNA Viruses: Role of the Intracellular Ca 2+/Mn 2+ Pump. J Virol 2019; 94:e01015-19. [PMID: 31597780 PMCID: PMC6912095 DOI: 10.1128/jvi.01015-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/07/2019] [Indexed: 01/18/2023] Open
Abstract
Recombination is one of the driving forces of viral evolution. RNA recombination events among similar RNA viruses are frequent, although RNA recombination could also take place among unrelated viruses. In this paper, we have established efficient interviral recombination systems based on yeast and plants. We show that diverse RNA viruses, including the plant viruses tomato bushy stunt virus, carnation Italian ringspot virus, and turnip crinkle virus-associated RNA; the insect plus-strand RNA [(+)RNA] viruses Flock House virus and Nodamura virus; and the double-stranded L-A virus of yeast, are involved in interviral recombination events. Most interviral recombinants are minus-strand recombinant RNAs, and the junction sites are not randomly distributed, but there are certain hot spot regions. Formation of interviral recombinants in yeast and plants is accelerated by depletion of the cellular SERCA-like Pmr1 ATPase-driven Ca2+/Mn2+ pump, regulating intracellular Ca2+ and Mn2+ influx into the Golgi apparatus from the cytosol. The interviral recombinants are generated by a template-switching mechanism during RNA replication by the viral replicase. Replication studies revealed that a group of interviral recombinants is replication competent in cell-free extracts, in yeast, and in the plant Nicotiana benthamiana We propose that there are major differences among the viral replicases to generate and maintain interviral recombinants. Altogether, the obtained data promote the model that host factors greatly contribute to the formation of recombinants among related and unrelated viruses. This is the first time that a host factor's role in affecting interviral recombination is established.IMPORTANCE Viruses with RNA genomes are abundant, and their genomic sequences show astonishing variation. Genetic recombination in RNA viruses is a major force behind their rapid evolution, enhanced pathogenesis, and adaptation to their hosts. We utilized a previously identified intracellular Ca2+/Mn2+ pump-deficient yeast to search for interviral recombinants. Noninfectious viral replication systems were used to avoid generating unwanted infectious interviral recombinants. Altogether, interviral RNA recombinants were observed between plant and insect viruses, and between a fungal double-stranded RNA (dsRNA) virus and an insect virus, in the yeast host. In addition, interviral recombinants between two plant virus replicon RNAs were identified in N. benthamiana plants, in which the intracellular Ca2+/Mn2+ pump was depleted. These findings underline the crucial role of the host in promoting RNA recombination among unrelated viruses.
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Affiliation(s)
- Nikolay Kovalev
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
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15
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Muslin C, Mac Kain A, Bessaud M, Blondel B, Delpeyroux F. Recombination in Enteroviruses, a Multi-Step Modular Evolutionary Process. Viruses 2019; 11:E859. [PMID: 31540135 PMCID: PMC6784155 DOI: 10.3390/v11090859] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/05/2019] [Accepted: 09/06/2019] [Indexed: 01/15/2023] Open
Abstract
RNA recombination is a major driving force in the evolution and genetic architecture shaping of enteroviruses. In particular, intertypic recombination is implicated in the emergence of most pathogenic circulating vaccine-derived polioviruses, which have caused numerous outbreaks of paralytic poliomyelitis worldwide. Recent experimental studies that relied on recombination cellular systems mimicking natural genetic exchanges between enteroviruses provided new insights into the molecular mechanisms of enterovirus recombination and enabled to define a new model of genetic plasticity for enteroviruses. Homologous intertypic recombinant enteroviruses that were observed in nature would be the final products of a multi-step process, during which precursor nonhomologous recombinant genomes are generated through an initial inter-genomic RNA recombination event and can then evolve into a diversity of fitter homologous recombinant genomes over subsequent intra-genomic rearrangements. Moreover, these experimental studies demonstrated that the enterovirus genome could be defined as a combination of genomic modules that can be preferentially exchanged through recombination, and enabled defining the boundaries of these recombination modules. These results provided the first experimental evidence supporting the theoretical model of enterovirus modular evolution previously elaborated from phylogenetic studies of circulating enterovirus strains. This review summarizes our current knowledge regarding the mechanisms of recombination in enteroviruses and presents a new evolutionary process that may apply to other RNA viruses.
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Affiliation(s)
- Claire Muslin
- One Health Research Group, Faculty of Health Sciences, Universidad de las Américas, Quito EC170125, Pichincha, Ecuador.
| | - Alice Mac Kain
- Institut Pasteur, Viral Populations and Pathogenesis Unit, CNRS UMR 3569, 75015 Paris, France.
| | - Maël Bessaud
- Institut Pasteur, Viral Populations and Pathogenesis Unit, CNRS UMR 3569, 75015 Paris, France.
| | - Bruno Blondel
- Institut Pasteur, Biology of Enteric Viruses Unit, 75015 Paris, France.
- INSERM U994, Institut National de la Santé et de la Recherche Médicale, 75015 Paris, France.
| | - Francis Delpeyroux
- Institut Pasteur, Biology of Enteric Viruses Unit, 75015 Paris, France.
- INSERM U994, Institut National de la Santé et de la Recherche Médicale, 75015 Paris, France.
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16
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Komorowska B, Hasiów-Jaroszewska B, Elena SF. Evolving by deleting: patterns of molecular evolution of Apple stem pitting virus isolates from Poland. J Gen Virol 2019; 100:1442-1456. [PMID: 31424379 DOI: 10.1099/jgv.0.001290] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study, 267 coat protein gene (CP) sequences from 48 Polish isolates of Apple stem pitting virus (ASPV) were determined. The genetic structure of the virus population was analysed and possible mechanisms of molecular evolution explored. We found evidence of recombination within the ASPV population and the presence of 17 ASPV molecular variants that differ in the length, number and arrangement of deletions in the CP. Population genetic analyses showed significant variation among isolates from pear and apple trees, between isolates from the same host species and, more interestingly, within isolates, supporting the existence of significant levels of variability within individual hosts, as expected by a quasispecies population structure. In addition, different tests support that selection might have been an important force driving diversification within isolates: positive selection was found acting upon certain amino acids. Phylogenetic analyses also showed that isolates did not classify according to the host species (pear or apple trees) but according to the pattern of deletions, suggesting a possible role for deletions during clade diversification.
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Affiliation(s)
- Beata Komorowska
- Research Institute of Horticulture, Department of Phytopathology, Konstytucji 3 Maja 1/3, 96-100 Skierniewice, Poland
| | - Beata Hasiów-Jaroszewska
- Department of Virology and Bacteriology, Institute of Plant Protection - National Research Institute, Wł. Węgorka 20, 60-318 Poznań, Poland
| | - Santiago F Elena
- The Santa Fe Institute, Santa Fe, NM 87501, USA.,Instituto de Biología Integrativa de Sistemas, CSIC-Universitat de València, 46980 Paterna, València, Spain
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17
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Defective viral genomes are key drivers of the virus-host interaction. Nat Microbiol 2019; 4:1075-1087. [PMID: 31160826 PMCID: PMC7097797 DOI: 10.1038/s41564-019-0465-y] [Citation(s) in RCA: 188] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 04/23/2019] [Indexed: 12/12/2022]
Abstract
Viruses survive often harsh host environments, yet we know little about the strategies they utilize to adapt and subsist given their limited genomic resources. We are beginning to appreciate the surprising versatility of viral genomes and how replication-competent and -defective virus variants can provide means for adaptation, immune escape and virus perpetuation. This Review summarizes current knowledge of the types of defective viral genomes generated during the replication of RNA viruses and the functions that they carry out. We highlight the universality and diversity of defective viral genomes during infections and discuss their predicted role in maintaining a fit virus population, their impact on human and animal health, and their potential to be harnessed as antiviral tools. This Review describes recent findings on the biogenesis and the role of defective viral genomes during replication of RNA viruses and discusses their impact on viral dynamics and evolution.
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18
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Zhang L, Shang J, Jia Q, Li K, Yang H, Liu H, Tang Z, Chang X, Zhang M, Wang W, Yang W. Genetic evolutionary analysis of soybean mosaic virus populations from three geographic locations in China based on the P1 and CP genes. Arch Virol 2019; 164:1037-1048. [PMID: 30747339 DOI: 10.1007/s00705-019-04165-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 01/11/2019] [Indexed: 01/14/2023]
Abstract
Soybean mosaic virus (SMV) is one of the major pathogens causing serious soybean losses. Little is known about the genetic structure and evolutionary biology of the SMV population in southwestern China. In this study, 29 SMV isolates were obtained from Sichuan Province, and the genomic regions encoding the first protein (P1) and coat protein (CP) were sequenced. Combined with SMV isolates from the southeastern and northeastern regions of China, the genetic and molecular evolution of SMV was studied. Recombination analysis revealed that intraspecific and interspecific recombination had occurred in the SMV population. A phylogenetic tree based on the P1 gene reflected the geographic origin of the non-interspecific recombinant SMV (SMV-NI), while a tree based on the CP gene did not. Though frequent gene flow of the SMV-NI populations was found between the southeastern and northeastern populations, the southwestern population was relatively independent. Genetic differentiation was significant between the SMV interspecific recombinant (SMV-RI) and the non-interspecific recombinant (SMV-NI) populations. It was interesting to note that there was an almost identical recombination breakpoint in SMV-RI and Watermelon mosaic virus (WMV). Population dynamics showed that SMV-RI might be in an expanding state, while the SMV-NI population is relatively stable.
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Affiliation(s)
- Lei Zhang
- Sichuan Engineering Research Center for Crop Strip Intercropping System and Key Laboratory of Crop Eco‑physiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Jing Shang
- Sichuan Engineering Research Center for Crop Strip Intercropping System and Key Laboratory of Crop Eco‑physiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China.
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Qi Jia
- Sichuan Engineering Research Center for Crop Strip Intercropping System and Key Laboratory of Crop Eco‑physiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Kai Li
- National Center for Soybean Improvement, National Key Laboratory for Crop Genetics and Germplasm Enhancement, Key Laboratory of Biology and Genetic Improvement of Soybean, Ministry of Agriculture, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Hui Yang
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Huanhuan Liu
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Zhongqin Tang
- Sichuan Engineering Research Center for Crop Strip Intercropping System and Key Laboratory of Crop Eco‑physiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xiaoli Chang
- Sichuan Engineering Research Center for Crop Strip Intercropping System and Key Laboratory of Crop Eco‑physiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Min Zhang
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Wenming Wang
- College of Agronomy and Key Laboratory for Major Crop Diseases, Sichuan Agricultural University, Chengdu, 611130, China
| | - Wenyu Yang
- Sichuan Engineering Research Center for Crop Strip Intercropping System and Key Laboratory of Crop Eco‑physiology and Farming System in Southwest China, Sichuan Agricultural University, Chengdu, 611130, China.
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Filomatori CV, Bardossy ES, Merwaiss F, Suzuki Y, Henrion A, Saleh MC, Alvarez DE. RNA recombination at Chikungunya virus 3'UTR as an evolutionary mechanism that provides adaptability. PLoS Pathog 2019; 15:e1007706. [PMID: 30986247 PMCID: PMC6502353 DOI: 10.1371/journal.ppat.1007706] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 05/06/2019] [Accepted: 03/15/2019] [Indexed: 11/18/2022] Open
Abstract
The potential of RNA viruses to adapt to new environments relies on their ability to introduce changes in their genomes, which has resulted in the recent expansion of re-emergent viruses. Chikungunya virus is an important human pathogen transmitted by mosquitoes that, after 60 years of exclusive circulation in Asia and Africa, has rapidly spread in Europe and the Americas. Here, we examined the evolution of CHIKV in different hosts and uncovered host-specific requirements of the CHIKV 3'UTR. Sequence repeats are conserved at the CHIKV 3'UTR but vary in copy number among viral lineages. We found that these blocks of repeated sequences favor RNA recombination processes through copy-choice mechanism that acts concertedly with viral selection, determining the emergence of new viral variants. Functional analyses using a panel of mutant viruses indicated that opposite selective pressures in mosquito and mammalian cells impose a fitness cost during transmission that is alleviated by recombination guided by sequence repeats. Indeed, drastic changes in the frequency of viral variants with different numbers of repeats were detected during host switch. We propose that RNA recombination accelerates CHIKV adaptability, allowing the virus to overcome genetic bottlenecks within the mosquito host. These studies highlight the role of 3'UTR plasticity on CHIKV evolution, providing a new paradigm to explain the significance of sequence repetitions.
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Affiliation(s)
- Claudia V. Filomatori
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Eugenia S. Bardossy
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Fernando Merwaiss
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
| | - Yasutsugu Suzuki
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - Annabelle Henrion
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - María Carla Saleh
- Institut Pasteur, Viruses and RNA Interference Unit, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - Diego E. Alvarez
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín, Buenos Aires, Argentina
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20
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Bentley K, Evans DJ. Mechanisms and consequences of positive-strand RNA virus recombination. J Gen Virol 2018; 99:1345-1356. [PMID: 30156526 DOI: 10.1099/jgv.0.001142] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Genetic recombination in positive-strand RNA viruses is a significant evolutionary mechanism that drives the creation of viral diversity by the formation of novel chimaeric genomes. The process and its consequences, for example the generation of viruses with novel phenotypes, has historically been studied by analysis of the end products. More recently, with an appreciation that there are both replicative and non-replicative mechanisms at work, and with new approaches and techniques to analyse intermediate products, the viral and cellular factors that influence the process are becoming understood. The major influence on replicative recombination is the fidelity of viral polymerase, although RNA structures and sequences may also have an impact. In replicative recombination the viral polymerase is necessary and sufficient, although roles for other viral or cellular proteins may exist. In contrast, non-replicative recombination appears to be mediated solely by cellular components. Despite these insights, the relative importance of replicative and non-replicative mechanisms is not clear. Using single-stranded positive-sense RNA viruses as exemplars, we review the current state of understanding of the processes and consequences of recombination.
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Affiliation(s)
- Kirsten Bentley
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, UK
| | - David J Evans
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, UK
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21
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Abstract
Due to their dependence on cellular organisms for metabolism and replication, viruses are typically named and assigned to species according to their genome structure and the original host that they infect. But because viruses often infect multiple hosts and the numbers of distinct lineages within a host can be vast, their delineation into species is often dictated by arbitrary sequence thresholds, which are highly inconsistent across lineages. Here we apply an approach to determine the boundaries of viral species based on the detection of gene flow within populations, thereby defining viral species according to the biological species concept (BSC). Despite the potential for gene transfer between highly divergent genomes, viruses, like the cellular organisms they infect, assort into reproductively isolated groups and can be organized into biological species. This approach revealed that BSC-defined viral species are often congruent with the taxonomic partitioning based on shared gene contents and host tropism, and that bacteriophages can similarly be classified in biological species. These results open the possibility to use a single, universal definition of species that is applicable across cellular and acellular lifeforms.
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22
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Willemsen A, Carrasco JL, Elena SF, Zwart MP. Going, going, gone: predicting the fate of genomic insertions in plant RNA viruses. Heredity (Edinb) 2018; 121:499-509. [PMID: 29743566 DOI: 10.1038/s41437-018-0086-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 11/09/2022] Open
Abstract
Horizontal gene transfer is common among viruses, while they also have highly compact genomes and tend to lose artificial genomic insertions rapidly. Understanding the stability of genomic insertions in viral genomes is therefore relevant for explaining and predicting their evolutionary patterns. Here, we revisit a large body of experimental research on a plant RNA virus, tobacco etch potyvirus (TEV), to identify the patterns underlying the stability of a range of homologous and heterologous insertions in the viral genome. We obtained a wide range of estimates for the recombination rate-the rate at which deletions removing the insertion occur-and these appeared to be independent of the type of insertion and its location. Of the factors we considered, recombination rate was the best predictor of insertion stability, although we could not identify the specific sequence characteristics that would help predict insertion instability. We also considered experimentally the possibility that functional insertions lead to higher mutational robustness through increased redundancy. However, our observations suggest that both functional and non-functional increases in genome size decreased the mutational robustness. Our results therefore demonstrate the importance of recombination rates for predicting the long-term stability and evolution of viral RNA genomes and suggest that there are unexpected drawbacks to increases in genome size for mutational robustness.
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Affiliation(s)
- Anouk Willemsen
- Laboratory MIVEGEC (UMR CNRS 5290, IRD 224, UM), National Center for Scientific Research (CNRS), Montpellier, France
| | - José L Carrasco
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain
| | - Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain.,Instituto de Biología Integrativa de Sistemas (I2SysBio), Consejo Superior de Investigaciones Científicas-Universitat de València, Paterna, Spain.,The Santa Fe Institute, Santa Fe, NM, 87501, USA
| | - Mark P Zwart
- Microbial Ecology Department, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands. .,Laboratory of Genetics, Wageningen University, Wageningen, The Netherlands.
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Hasiów-Jaroszewska B, Minicka J, Zarzyńska-Nowak A, Budzyńska D, Elena SF. Defective RNA particles derived from Tomato black ring virus genome interfere with the replication of parental virus. Virus Res 2018; 250:87-94. [PMID: 29665369 DOI: 10.1016/j.virusres.2018.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/05/2018] [Accepted: 04/10/2018] [Indexed: 12/18/2022]
Abstract
Tomato black ring virus (TBRV) is the only member of the Nepovirus genus that is known to form defective RNA particles (D RNAs) during replication. Here, de novo generation of D RNAs was observed during prolonged passages of TBRV isolates originated from Solanum lycopersicum and Lactuca sativa in Chenopodium quinoa plants. D RNAs of about 500 nt derived by a single deletion in the RNA1 molecule and contained a portion of the 5' untranslated region and viral replicase, and almost the entire 3' non-coding region. Short regions of sequence complementarity were found at the 5' and 3' junction borders, which can facilitate formation of the D RNAs. Moreover, in this study we analyzed the effects of D RNAs on TBRV replication and symptoms development of infected plants. C. quinoa, S. lycopersicum, Nicotiana tabacum, and L. sativa were infected with the original TBRV isolates (TBRV-D RNA) and those containing additional D RNA particles (TBRV + D RNA). The viral accumulation in particular hosts was measured up to 28 days post inoculation by RT-qPCR. Statistical analyses revealed that D RNAs interfere with TBRV replication and thus should be referred to as defective interfering particles. The magnitude of the interference effect depends on the interplay between TBRV isolate and host species.
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Affiliation(s)
- Beata Hasiów-Jaroszewska
- Institute of Plant Protection-National Research Institute, Department of Virology and Bacteriology, ul. Wł. Węgorka 20, 60-318 Poznań, Poland.
| | - Julia Minicka
- Institute of Plant Protection-National Research Institute, Department of Virology and Bacteriology, ul. Wł. Węgorka 20, 60-318 Poznań, Poland
| | - Aleksandra Zarzyńska-Nowak
- Institute of Plant Protection-National Research Institute, Department of Virology and Bacteriology, ul. Wł. Węgorka 20, 60-318 Poznań, Poland
| | - Daria Budzyńska
- Institute of Plant Protection-National Research Institute, Department of Virology and Bacteriology, ul. Wł. Węgorka 20, 60-318 Poznań, Poland
| | - Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universitat Politècnica de València, València, Spain; Instituto de Biología Integrativa de Sistemas, Consejo Superior de Investigaciones Científicas-Universitat de València, València, Spain; The Santa Fe Institute, Santa Fe, New Mexico, USA
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24
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Garcia-Ruiz H, Diaz A, Ahlquist P. Intermolecular RNA Recombination Occurs at Different Frequencies in Alternate Forms of Brome Mosaic Virus RNA Replication Compartments. Viruses 2018; 10:v10030131. [PMID: 29543718 PMCID: PMC5869524 DOI: 10.3390/v10030131] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 01/27/2023] Open
Abstract
Positive-strand RNA viruses replicate their genomes in membrane-bound replication compartments. Brome mosaic virus (BMV) replicates in vesicular invaginations of the endoplasmic reticulum membrane. BMV has served as a productive model system to study processes like virus-host interactions, RNA replication and recombination. Here we present multiple lines of evidence showing that the structure of the viral RNA replication compartments plays a fundamental role and that recruitment of parental RNAs to a common replication compartment is a limiting step in intermolecular RNA recombination. We show that a previously defined requirement for an RNA recruitment element on both parental RNAs is not to function as a preferred crossover site, but in order for individual RNAs to be recruited into the replication compartments. Moreover, modulating the form of the replication compartments from spherular vesicles (spherules) to more expansive membrane layers increased intermolecular RNA recombination frequency by 200- to 1000-fold. We propose that intermolecular RNA recombination requires parental RNAs to be recruited into replication compartments as monomers, and that recruitment of multiple RNAs into a contiguous space is much more common for layers than for spherules. These results could explain differences in recombination frequencies between viruses that replicate in association with smaller spherules versus larger double-membrane vesicles and convoluted membranes.
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Affiliation(s)
- Hernan Garcia-Ruiz
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706, USA.
- Nebraska Center for Virology, Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68503, USA.
| | - Arturo Diaz
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706, USA.
- Department of Biology, La Sierra University, Riverside, CA 92515, USA.
| | - Paul Ahlquist
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706, USA.
- Howard Hughes Medical Institute and Morgridge Institute for Research, University of Wisconsin-Madison, MadisonWI 53706, USA.
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25
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Ding XS, Mannas SW, Bishop BA, Rao X, Lecoultre M, Kwon S, Nelson RS. An Improved Brome mosaic virus Silencing Vector: Greater Insert Stability and More Extensive VIGS. PLANT PHYSIOLOGY 2018; 176:496-510. [PMID: 29127260 PMCID: PMC5761774 DOI: 10.1104/pp.17.00905] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 11/09/2017] [Indexed: 05/07/2023]
Abstract
Virus-induced gene silencing (VIGS) is used extensively for gene function studies in plants. VIGS is inexpensive and rapid compared with silencing conducted through stable transformation, but many virus-silencing vectors, especially in grasses, induce only transient silencing phenotypes. A major reason for transient phenotypes is the instability of the foreign gene fragment (insert) in the vector during VIGS. Here, we report the development of a Brome mosaic virus (BMV)-based vector that better maintains inserts through modification of the original BMV vector RNA sequence. Modification of the BMV RNA3 sequence yielded a vector, BMVCP5, that better maintained phytoene desaturase and heat shock protein70-1 (HSP70-1) inserts in Nicotiana benthamiana and maize (Zea mays). Longer maintenance of inserts was correlated with greater target gene silencing and more extensive visible silencing phenotypes displaying greater tissue penetration and involving more leaves. The modified vector accumulated similarly to the original vector in N. benthamiana after agroinfiltration, thus maintaining a high titer of virus in this intermediate host used to produce virus inoculum for grass hosts. For HSP70, silencing one family member led to a large increase in the expression of another family member, an increase likely related to the target gene knockdown and not a general effect of virus infection. The cause of the increased insert stability in the modified vector is discussed in relationship to its recombination and accumulation potential. The modified vector will improve functional genomic studies in grasses, and the conceptual methods used to improve the vector may be applied to other VIGS vectors.
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Affiliation(s)
- Xin Shun Ding
- Noble Research Institute, LLC, Ardmore, Oklahoma 73401
| | | | | | - Xiaolan Rao
- BioDiscovery Institute and Department of Biological Sciences, University of North Texas, Denton, Texas 76203
| | | | - Soonil Kwon
- Noble Research Institute, LLC, Ardmore, Oklahoma 73401
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26
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Kleine Büning M, Meyer D, Austermann-Busch S, Roman-Sosa G, Rümenapf T, Becher P. Nonreplicative RNA Recombination of an Animal Plus-Strand RNA Virus in the Absence of Efficient Translation of Viral Proteins. Genome Biol Evol 2017; 9:817-829. [PMID: 28338950 PMCID: PMC5381556 DOI: 10.1093/gbe/evx046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2017] [Indexed: 12/27/2022] Open
Abstract
RNA recombination is a major driving force for the evolution of RNA viruses and is significantly implicated in the adaptation of viruses to new hosts, changes of virulence, as well as in the emergence of new viruses including drug-resistant and escape mutants. However, the molecular details of recombination in animal RNA viruses are only poorly understood. In order to determine whether viral RNA recombination depends on translation of viral proteins, a nonreplicative recombination system was established which is based on cotransfection of cells with synthetic bovine viral diarrhea virus (family Flaviviridae) RNA genome fragments either lacking the internal ribosome entry site required for cap-independent translation or lacking almost the complete polyprotein coding region. The emergence of a number of recombinant viruses demonstrated that IRES-mediated translation of viral proteins is dispensable for efficient recombination and suggests that RNA recombination can occur in the absence of viral proteins. Analyses of 58 independently emerged viruses led to the detection of recombinant genomes with duplications, deletions and insertions in the 5′ terminal region of the open reading frame, leading to enlarged core fusion proteins detectable by Western blot analysis. This demonstrates a remarkable flexibility of the pestivirus core protein. Further experiments with capped and uncapped genome fragments containing a luciferase gene for monitoring the level of protein translation revealed that even a ∼1,000-fold enhancement of translation of viral proteins did not increase the frequency of RNA recombination. Taken together, this study highlights that nonreplicative RNA recombination does not require translation of viral proteins.
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Affiliation(s)
- Maximiliane Kleine Büning
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Germany
| | - Denise Meyer
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Germany
| | - Sophia Austermann-Busch
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Germany
| | | | - Tillmann Rümenapf
- Department of Pathobiology, Institute of Virology, University of Veterinary Medicine Vienna, Austria
| | - Paul Becher
- Department of Infectious Diseases, Institute of Virology, University of Veterinary Medicine Hannover, Germany
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27
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Prasanth KR, Kovalev N, de Castro Martín IF, Baker J, Nagy PD. Screening a yeast library of temperature-sensitive mutants reveals a role for actin in tombusvirus RNA recombination. Virology 2016; 489:233-42. [DOI: 10.1016/j.virol.2015.12.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 08/15/2015] [Accepted: 12/14/2015] [Indexed: 01/21/2023]
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28
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Eusebio-Cope A, Suzuki N. Mycoreovirus genome rearrangements associated with RNA silencing deficiency. Nucleic Acids Res 2015; 43:3802-13. [PMID: 25800742 PMCID: PMC4402544 DOI: 10.1093/nar/gkv239] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 03/06/2015] [Indexed: 01/31/2023] Open
Abstract
Mycoreovirus 1 (MyRV1) has 11 double-stranded RNA genome segments (S1 to S11) and confers hypovirulence to the chestnut blight fungus, Cryphonectria parasitica. MyRV1 genome rearrangements are frequently generated by a multifunctional protein, p29, encoded by a positive-strand RNA virus, Cryphonectria hypovirus 1. One of its functional roles is RNA silencing suppression. Here, we explored a possible link between MyRV1 genome rearrangements and the host RNA silencing pathway using wild-type (WT) and mutant strains of both MyRV1 and the host fungus. Host strains included deletion mutants of RNA silencing components such as dicer-like (dcl) and argonaute-like (agl) genes, while virus strains included an S4 internal deletion mutant MyRV1/S4ss. Consequently, intragenic rearrangements with nearly complete duplication of the three largest segments, i.e. S1, S2 and S3, were observed even more frequently in the RNA silencing-deficient strains Δdcl2 and Δagl2 infected with MyRV1/S4ss, but not with any other viral/host strain combinations. An interesting difference was noted between genome rearrangement events in the two host strains, i.e. generation of the rearrangement required prolonged culture for Δagl2 in comparison with Δdcl2. These results suggest a role for RNA silencing that suppresses genome rearrangements of a dsRNA virus.
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Affiliation(s)
- Ana Eusebio-Cope
- Agrivirology Laboratory, Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - Nobuhiro Suzuki
- Agrivirology Laboratory, Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
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29
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Chuang C, Prasanth KR, Nagy PD. Coordinated function of cellular DEAD-box helicases in suppression of viral RNA recombination and maintenance of viral genome integrity. PLoS Pathog 2015; 11:e1004680. [PMID: 25693185 PMCID: PMC4333740 DOI: 10.1371/journal.ppat.1004680] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Accepted: 01/12/2015] [Indexed: 12/16/2022] Open
Abstract
The intricate interactions between viruses and hosts include an evolutionary arms race and adaptation that is facilitated by the ability of RNA viruses to evolve rapidly due to high frequency mutations and genetic RNA recombination. In this paper, we show evidence that the co-opted cellular DDX3-like Ded1 DEAD-box helicase suppresses tombusviral RNA recombination in yeast model host, and the orthologous RH20 helicase functions in a similar way in plants. In vitro replication and recombination assays confirm the direct role of the ATPase function of Ded1p in suppression of viral recombination. We also present data supporting a role for Ded1 in facilitating the switch from minus- to plus-strand synthesis. Interestingly, another co-opted cellular helicase, the eIF4AIII-like AtRH2, enhances TBSV recombination in the absence of Ded1/RH20, suggesting that the coordinated actions of these helicases control viral RNA recombination events. Altogether, these helicases are the first co-opted cellular factors in the viral replicase complex that directly affect viral RNA recombination. Ded1 helicase seems to be a key factor maintaining viral genome integrity by promoting the replication of viral RNAs with correct termini, but inhibiting the replication of defective RNAs lacking correct 5' end sequences. Altogether, a co-opted cellular DEAD-box helicase facilitates the maintenance of full-length viral genome and suppresses viral recombination, thus limiting the appearance of defective viral RNAs during replication.
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Affiliation(s)
- Chingkai Chuang
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
| | - K. Reddisiva Prasanth
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Peter D. Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, United States of America
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30
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Lin X, Thorne L, Jin Z, Hammad LA, Li S, Deval J, Goodfellow IG, Kao CC. Subgenomic promoter recognition by the norovirus RNA-dependent RNA polymerases. Nucleic Acids Res 2014; 43:446-60. [PMID: 25520198 PMCID: PMC4288183 DOI: 10.1093/nar/gku1292] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The replication enzyme of RNA viruses must preferentially recognize their RNAs in an environment that contains an abundance of cellular RNAs. The factors responsible for specific RNA recognition are not well understood, in part because viral RNA synthesis takes place within enzyme complexes associated with modified cellular membrane compartments. Recombinant RNA-dependent RNA polymerases (RdRps) from the human norovirus and the murine norovirus (MNV) were found to preferentially recognize RNA segments that contain the promoter and a short template sequence for subgenomic RNA synthesis. Both the promoter and template sequence contribute to stable RdRp binding, accurate initiation of the subgenomic RNAs and efficient RNA synthesis. Using a method that combines RNA crosslinking and mass spectrometry, residues near the template channel of the MNV RdRp were found to contact the hairpin RNA motif. Mutations in the hairpin contact site in the MNV RdRp reduced MNV replication and virus production in cells. This work demonstrates that the specific recognition of the norovirus subgenomic promoter is through binding by the viral RdRp.
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Affiliation(s)
- Xiaoyan Lin
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Lucy Thorne
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road CB2 2QQ, UK
| | - Zhinan Jin
- Alios BioPharma, Inc., 260 East Grand Avenue South, San Francisco, CA 94080, USA
| | - Loubna A Hammad
- Laboratory for Biological Mass Spectrometry, Indiana University, Bloomington, IN 47405, USA
| | - Serena Li
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
| | - Jerome Deval
- Alios BioPharma, Inc., 260 East Grand Avenue South, San Francisco, CA 94080, USA
| | - Ian G Goodfellow
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road CB2 2QQ, UK
| | - C Cheng Kao
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
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31
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Martella V, Pinto P, Tummolo F, De Grazia S, Giammanco GM, Medici MC, Ganesh B, L'Homme Y, Farkas T, Jakab F, Bányai K. Analysis of the ORF2 of human astroviruses reveals lineage diversification, recombination and rearrangement and provides the basis for a novel sub-classification system. Arch Virol 2014; 159:3185-96. [PMID: 25326755 DOI: 10.1007/s00705-014-2153-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/16/2014] [Indexed: 11/26/2022]
Abstract
Canonical human astroviruses (HAstVs) are important enteric pathogens that can be classified genetically and antigenically into eight types. Sequence analysis of small diagnostic regions at either the 5' or 3' end of ORF2 (capsid precursor) is a good proxy for prediction of HAstV types and for distinction of intratypic genetic lineages (subtypes), although lineage diversification/classification has not been investigated systematically. Upon sequence and phylogenetic analysis of the full-length ORF2 of 86 HAstV strains selected from the databases, a detailed classification of HAstVs into lineages was established. Three main lineages could be defined in HAstV-1, four in HAstV-2, two in HAstV-3, three in HAstV-4, three in HAstV-5 and two in HAstV-6. Intratypic (inter-lineages) ORF2 recombinant strains were identified in type 1 (1b/1d) and type 2 (2c/2b) with distinct crossover points. Other potential intratypic recombinant strains were identified in type 3, type 5 and type 6. In addition, a type-1b strain with a large insertion (~600 bp) of heterologous RNA in the N-terminal region and a type-6 strain with a large RNA rearrangement in the hypervariable region were identified. The classification scheme was integrated in a novel nomenclature system suitable for designation of HAstV strains.
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Affiliation(s)
- Vito Martella
- Dipartimento di Medicina Veterinaria, Università Aldo Moro di Bari, Valenzano, Italy,
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32
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Galli A, Bukh J. Comparative analysis of the molecular mechanisms of recombination in hepatitis C virus. Trends Microbiol 2014; 22:354-64. [DOI: 10.1016/j.tim.2014.02.005] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 02/10/2014] [Accepted: 02/13/2014] [Indexed: 12/17/2022]
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Gebauer M, Behrens M, König M, Behrens SE. A bi-cistronic, reporter-encoding bovine viral diarrhea virus applied in a new, effective diagnostic test. J Gen Virol 2014; 95:1522-1531. [PMID: 24760759 DOI: 10.1099/vir.0.063800-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Infections with bovine viral diarrhea virus (BVDV) have a huge economic impact on cattle production and reproduction worldwide. A key factor for BVDV surveillance and eventual eradication is to efficiently detect infections and to monitor herd immunity. In this study, we generated a stable, bi-cistronic BVDV that encoded EGFP in addition to the viral proteins. Applying this recombinant virus, a new flow-cytometry-based virus neutralization test was established that enabled accurate and reliable detection of field-virus-infected and vaccinated animals. The test, which is simple and fast, is expected to support novel, effective screening procedures in eradication and vaccination programmes.
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Affiliation(s)
- Mandy Gebauer
- Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NFI), Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Martina Behrens
- Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NFI), Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Matthias König
- Institue of Virology, Faculty of Veterinary Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - Sven-Erik Behrens
- Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NFI), Martin Luther University Halle-Wittenberg, Halle, Germany
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34
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Hull R. Replication of Plant Viruses. PLANT VIROLOGY 2014. [PMCID: PMC7184227 DOI: 10.1016/b978-0-12-384871-0.00007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Viruses replicate using both their own genetic information and host cell components and machinery. The different genome types have different replication pathways which contain controls on linking the process with translation and movement around the cell as well as not compromising the infected cell. This chapter discusses the replication mechanisms, faults in replication and replication of viruses co-infecting cells. Viruses replicate using both their own genetic information and host cell components and machinery. The different genome types have different replication pathways which contain controls on linking the process with translation and movement around the cell as well as not compromising the infected cell. This chapter discusses the replication mechanisms, faults in replication and replication of viruses coinfecting cells.
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35
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Ramanna H, Ding XS, Nelson RS. Rationale for developing new virus vectors to analyze gene function in grasses through virus-induced gene silencing. Methods Mol Biol 2013; 975:15-32. [PMID: 23386292 DOI: 10.1007/978-1-62703-278-0_2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The exploding availability of genome and EST-based sequences from grasses requires a technology that allows rapid functional analysis of the multitude of genes that these resources provide. There are several techniques available to determine a gene's function. For gene knockdown studies, silencing through RNAi is a powerful tool. Gene silencing can be accomplished through stable transformation or transient expression of a fragment of a target gene sequence. Stable transformation in rice, maize, and a few other species, although routine, remains a relatively low-throughput process. Transformation in other grass species is difficult and labor-intensive. Therefore, transient gene silencing methods including Agrobacterium-mediated and virus-induced gene silencing (VIGS) have great potential for researchers studying gene function in grasses. VIGS in grasses already has been used to determine the function of genes during pathogen challenge and plant development. It also can be used in moderate-throughput reverse genetics screens to determine gene function. However, the number of viruses modified to serve as silencing vectors in grasses is limited, and the silencing phenotype induced by these vectors is not optimal: the phenotype being transient and with moderate penetration throughout the tissue. Here, we review the most recent information available for VIGS in grasses and summarize the strengths and weaknesses in current virus-grass host systems. We describe ways to improve current virus vectors and the potential of other grass-infecting viruses for VIGS studies. This work is necessary because VIGS for the foreseeable future remains a higher throughput and more rapid system to evaluate gene function than stable transformation.
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Affiliation(s)
- Hema Ramanna
- Plant Biology Division, The Samuel Roberts Noble Foundation Inc., Ardmore, OK, USA
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36
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Villabona-Arenas CJ, de Brito AF, de Andrade Zanotto PM. Genomic mosaicism in two strains of Dengue virus type 3. INFECTION GENETICS AND EVOLUTION 2013; 18:202-12. [PMID: 23727343 DOI: 10.1016/j.meegid.2013.05.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 05/14/2013] [Accepted: 05/15/2013] [Indexed: 11/28/2022]
Abstract
Recombination is a significant factor driving genomic evolution, but it is not well understood in Dengue virus. We used phylogenetic methods to search for recombination in 636 Dengue virus type 3 (DENV-3) genomes and unveiled complex recombination patterns in two strains, which appear to be the outcome of recombination between genotype II and genotype I parental DENV-3 lineages. Our findings of genomic mosaic structures suggest that strand switching during RNA synthesis may be involved in the generation of genetic diversity in dengue viruses.
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Affiliation(s)
- Christian Julián Villabona-Arenas
- Laboratory of Molecular Evolution and Bioinformatics, Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes 1734, CEP: 05508-000, São Paulo, SP, Brazil
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37
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Bujarski JJ. Genetic recombination in plant-infecting messenger-sense RNA viruses: overview and research perspectives. FRONTIERS IN PLANT SCIENCE 2013; 4:68. [PMID: 23533000 PMCID: PMC3607795 DOI: 10.3389/fpls.2013.00068] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/11/2013] [Indexed: 05/09/2023]
Abstract
RNA recombination is one of the driving forces of genetic variability in (+)-strand RNA viruses. Various types of RNA-RNA crossovers were described including crosses between the same or different viral RNAs or between viral and cellular RNAs. Likewise, a variety of molecular mechanisms are known to support RNA recombination, such as replicative events (based on internal or end-to-end replicase switchings) along with non-replicative joining among RNA fragments of viral and/or cellular origin. Such mechanisms as RNA decay or RNA interference are responsible for RNA fragmentation and trans-esterification reactions which are likely accountable for ligation of RNA fragments. Numerous host factors were found to affect the profiles of viral RNA recombinants and significant differences in recombination frequency were observed among various RNA viruses. Comparative analyses of viral sequences allowed for the development of evolutionary models in order to explain adaptive phenotypic changes and co-evolving sites. Many questions remain to be answered by forthcoming RNA recombination research. (1) How various factors modulate the ability of viral replicase to switch templates, (2) What is the intracellular location of RNA-RNA template switchings, (3) Mechanisms and factors responsible for non-replicative RNA recombination, (4) Mechanisms of integration of RNA viral sequences with cellular genomic DNA, and (5) What is the role of RNA splicing and ribozyme activity. From an evolutionary stand point, it is not known how RNA viruses parasitize new host species via recombination, nor is it obvious what the contribution of RNA recombination is among other RNA modification pathways. We do not understand why the frequency of RNA recombination varies so much among RNA viruses and the status of RNA recombination as a form of sex is not well documented.
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Affiliation(s)
- Jozef J. Bujarski
- Plant Molecular Biology Center and the Department of Biological Sciences, Northern Illinois UniversityDeKalb, IL, USA
- Laboratory of Molecular and Systems Biology, Institute of Bioorganic Chemistry, Polish Academy of SciencesPoznan, Poland
- *Correspondence: Jozef J. Bujarski, Plant Molecular Biology Center and the Department of Biological Sciences, Northern Illinois University, Montgomery Hall, DeKalb, IL 60115, USA. e-mail:
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Kwon SJ, Rao ALN. Emergence of distinct brome mosaic virus recombinants is determined by the polarity of the inoculum RNA. J Virol 2012; 86:5204-20. [PMID: 22357282 PMCID: PMC3347362 DOI: 10.1128/jvi.00351-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 02/14/2012] [Indexed: 12/22/2022] Open
Abstract
Despite overwhelming interest in the impact exerted by recombination during evolution of RNA viruses, the relative contribution of the polarity of inoculum templates remains poorly understood. Here, by agroinfiltrating Nicotiana benthamiana leaves, we show that brome mosaic virus (BMV) replicase is competent to initiate positive-strand [(+)-strand] synthesis on an ectopically expressed RNA3 negative strand [(-) strand] and faithfully complete the replication cycle. Consequently, we sought to examine the role of RNA polarity in BMV recombination by expressing a series of replication-defective mutants of BMV RNA3 in (+) or (-) polarity. Temporal analysis of progeny sequences revealed that the genetic makeup of the primary recombinant pool is determined by the polarity of the inoculum template. When the polarity of the inoculum template was (+), the recombinant pool that accumulated during early phases of replication was a mixture of nonhomologous recombinants. These are longer than the inoculum template length, and a nascent 3' untranslated region (UTR) of wild-type (WT) RNA1 or RNA2 was added to the input mutant RNA3 3' UTR due to end-to-end template switching by BMV replicase during (-)-strand synthesis. In contrast, when the polarity of the inoculum was (-), the progeny contained a pool of native-length homologous recombinants generated by template switching of BMV replicase with a nascent UTR from WT RNA1 or RNA2 during (+)-strand synthesis. Repair of a point mutation caused by polymerase error occurred only when the polarity of the inoculum template was (+). These results contribute to the explanation of the functional role of RNA polarity in recombination mediated by copy choice mechanisms.
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Affiliation(s)
- Sun-Jung Kwon
- Department of Plant Pathology & Microbiology, University of California, Riverside, California, USA
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RNA structural elements determine frequency and sites of nonhomologous recombination in an animal plus-strand RNA virus. J Virol 2012; 86:7393-402. [PMID: 22532677 DOI: 10.1128/jvi.00864-12] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For highly variable RNA viruses, RNA recombination significantly contributes to genetic variations which may lead to changes of virulence, adaptation to new hosts, escape from the host immune response, and emergence of new infectious agents. Using a system based on transfection of cells with synthetic nonreplicable subgenomic transcripts derived from bovine viral diarrhea virus (family Flaviviridae), the existence of a replication-independent mechanism of RNA recombination, in addition to the commonly accepted replicative copy-choice recombination, has been previously proven (A. Gallei et al., J. Virol. 78:6271-6281, 2004). To identify RNA signals involved in efficient joining of RNA molecules, RNA recombination in living cells was targeted to the 3' nontranslated region. Molecular characterization of 40 independently emerged recombinant viruses revealed that the majority of recombination sites are located in single-stranded regions of the RNA molecules. Furthermore, the results of this study showed that the frequency of RNA recombination directly correlated with the RNA amounts of both recombination partners. The frequency can be strongly increased by modification of the 5' triphosphates and 3' hydroxyls of the recombining RNA molecules to 5' hydroxyl and 3' monophosphoryl ends, respectively. Analysis of recombinants that emerged after transfection with such modified RNA molecules revealed a complete integration and efficient end-to-end joining of the recombination partner(s) in at least 80% of recombinants, while unmodified RNA molecules recombined exclusively at internal positions. These results are in line with the hypothesis that endoribonucleolytic cleavage and a subsequent ligation reaction can cause RNA recombination.
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Dzianott A, Sztuba-Solińska J, Bujarski JJ. Mutations in the antiviral RNAi defense pathway modify Brome mosaic virus RNA recombinant profiles. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:97-106. [PMID: 21936664 DOI: 10.1094/mpmi-05-11-0137] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
RNA interference (RNAi) mechanism targets viral RNA for degradation. To test whether RNAi gene products contributed to viral RNA recombination, a series of Arabidopsis thaliana RNAi-defective mutants were infected with Brome mosaic virus (BMV) RNAs that have been engineered to support crossovers within the RNA3 segment. Single-cross RNA3-RNA1, RNA3-RNA2, and RNA3-RNA3 recombinants accumulated in both the wild-type (wt) and all knock-out lines at comparable frequencies. However, a reduced accumulation of novel 3' mosaic RNA3 recombinants was observed in ago1, dcl2, dcl4, and rdr6 lines but not in wt Col-0 or the dcl3 line. A BMV replicase mutant accumulated a low level of RNA3-RNA1 single-cross recombinants in Col-0 plants while, in a dcl2 dcl4 double mutant, the formation of both RNA3-RNA1 and mosaic recombinants was at a low level. A control infection in the cpr5-2 mutant, a more susceptible BMV Arabidopsis host, generated similar-to-Col-0 profiles of both single-cross and mosaic recombinants, indicating that recombinant profiles were, to some extent, independent of a viral replication rate. Also, the relative growth experiments revealed similar selection pressure for recombinants among the host lines. Thus, the altered recombinant RNA profiles have originated at the level of recombinant formation rather than because of altered selection. In conclusion, the viral replicase and the host RNAi gene products contribute in distinct ways to BMV RNA recombination. Our studies reveal that the antiviral RNAi mechanisms are utilized by plant RNA viruses to increase their variability, reminiscent of phenomena previously demonstrated in fungi.
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Affiliation(s)
- Aleksandra Dzianott
- Department of Biological sciences, Northern Illinois University, DeKalb, IL, USA
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Hasiów-Jaroszewska B, Borodynko N, Figlerowicz M, Pospieszny H. Two types of defective RNAs arising from the tomato black ring virus genome. Arch Virol 2011; 157:569-72. [DOI: 10.1007/s00705-011-1200-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Accepted: 11/18/2011] [Indexed: 11/29/2022]
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Abstract
RNA viruses are the champions of evolution due to high frequency mutations and genetic recombination occurring during virus replication. These genetic events are due to the error-prone nature of viral RNA-dependent RNA polymerases (RdRp). Recently emerging models on viral RNA recombination, however, also include key roles for host and environmental factors. Accordingly, genome-wide screens and global proteomics approaches with Tomato bushy stunt virus (TBSV) and yeast (Saccharomyces cerevisiae) as a model host have identified 38 host proteins affecting viral RNA recombination. Follow-up studies have identified key host proteins and cellular pathways involved in TBSV RNA recombination. In addition, environmental factors, such as salt stress, have been shown to affect TBSV recombination via influencing key host or viral factors involved in the recombination process. These advances will help build more accurate models on viral recombination, evolution, and adaptation.
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Sztuba-Solińska J, Urbanowicz A, Figlerowicz M, Bujarski JJ. RNA-RNA recombination in plant virus replication and evolution. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:415-43. [PMID: 21529157 DOI: 10.1146/annurev-phyto-072910-095351] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
RNA-RNA recombination is one of the strongest forces shaping the genomes of plant RNA viruses. The detection of recombination is a challenging task that prompted the development of both in vitro and in vivo experimental systems. In the divided genome of Brome mosaic virus system, both inter- and intrasegmental crossovers are described. Other systems utilize satellite or defective interfering RNAs (DI-RNAs) of Turnip crinkle virus, Tomato bushy stunt virus, Cucumber necrosis virus, and Potato virus X. These assays identified the mechanistic details of the recombination process, revealing the role of RNA structure and proteins in the replicase-mediated copy-choice mechanism. In copy choice, the polymerase and the nascent RNA chain from which it is synthesized switch from one RNA template to another. RNA recombination was found to mediate the rearrangement of viral genes, the repair of deleterious mutations, and the acquisition of nonself sequences influencing the phylogenetics of viral taxa. The evidence for recombination, not only between related viruses but also among distantly related viruses, and even with host RNAs, suggests that plant viruses unabashedly test recombination with any genetic material at hand.
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Affiliation(s)
- Joanna Sztuba-Solińska
- Plant Molecular Biology Center, Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois 60115, USA
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Jaag HM, Nagy PD. The combined effect of environmental and host factors on the emergence of viral RNA recombinants. PLoS Pathog 2010; 6:e1001156. [PMID: 20975943 PMCID: PMC2958810 DOI: 10.1371/journal.ppat.1001156] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 09/20/2010] [Indexed: 12/31/2022] Open
Abstract
Viruses are masters of evolution due to high frequency mutations and genetic recombination. In spite of the significance of viral RNA recombination that promotes the emergence of drug-resistant virus strains, the role of host and environmental factors in RNA recombination is poorly understood. Here we report that the host Met22p/Hal2p bisphosphate-3'-nucleotidase regulates the frequency of viral RNA recombination and the efficiency of viral replication. Based on Tomato bushy stunt virus (TBSV) and yeast as a model host, we demonstrate that deletion of MET22 in yeast or knockdown of AHL, SAL1 and FRY1 nucleotidases/phosphatases in plants leads to increased TBSV recombination and replication. Using a cell-free TBSV recombination/replication assay, we show that the substrate of the above nucleotidases, namely 3'-phosphoadenosine-5'-phosphate pAp, inhibits the activity of the Xrn1p 5'-3' ribonuclease, a known suppressor of TBSV recombination. Inhibition of the activity of the nucleotidases by LiCl and NaCl also leads to increased TBSV recombination, demonstrating that environmental factors could also affect viral RNA recombination. Thus, host factors in combination with environmental factors likely affect virus evolution and adaptation.
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MESH Headings
- Environment
- Evolution, Molecular
- Host-Pathogen Interactions/genetics
- Host-Pathogen Interactions/physiology
- Models, Biological
- Nucleotidases/genetics
- Nucleotidases/metabolism
- Nucleotidases/physiology
- Organisms, Genetically Modified
- RNA/genetics
- RNA/metabolism
- RNA Splicing/physiology
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Recombination, Genetic/drug effects
- Recombination, Genetic/physiology
- Saccharomyces cerevisiae/drug effects
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae/virology
- Salts/pharmacology
- Stress, Physiological/drug effects
- Stress, Physiological/genetics
- Stress, Physiological/physiology
- Nicotiana/drug effects
- Nicotiana/genetics
- Nicotiana/metabolism
- Tombusvirus/genetics
- Tombusvirus/physiology
- Virus Replication/genetics
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Affiliation(s)
- Hannah M. Jaag
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, Kentucky, United States of America
| | - Peter D. Nagy
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, Kentucky, United States of America
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Regulation of de novo-initiated RNA synthesis in hepatitis C virus RNA-dependent RNA polymerase by intermolecular interactions. J Virol 2010; 84:5923-35. [PMID: 20375156 DOI: 10.1128/jvi.02446-09] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp) has been proposed to change conformations in association with RNA synthesis and to interact with cellular proteins. In vitro, the RdRp can initiate de novo from the ends of single-stranded RNA or extend a primed RNA template. The interactions between the Delta1 loop and thumb domain in NS5B are required for de novo initiation, although it is unclear whether these interactions are within an NS5B monomer or are part of a higher-order NS5B oligomeric complex. This work seeks to address how polymerase conformation and/or oligomerization affects de novo initiation. We have shown that an increasing enzyme concentration increases de novo initiation by the genotype 1b and 2a RdRps while primer extension reactions are not affected or inhibited under similar conditions. Initiation-defective mutants of the HCV polymerase can increase de novo initiation by the wild-type (WT) polymerase. GTP was also found to stimulate de novo initiation. Our results support a model in which the de novo initiation-competent conformation of the RdRp is stimulated by oligomeric contacts between individual subunits. Using electron microscopy and single-molecule reconstruction, we attempted to visualize the low-resolution conformations of a dimer of a de novo initiation-competent HCV RdRp.
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Jaag HM, Pogany J, Nagy PD. A host Ca2+/Mn2+ ion pump is a factor in the emergence of viral RNA recombinants. Cell Host Microbe 2010; 7:74-81. [PMID: 20114029 DOI: 10.1016/j.chom.2009.12.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 10/16/2009] [Accepted: 12/21/2009] [Indexed: 10/19/2022]
Abstract
Viruses change rapidly due to genetic mutations, and viral RNA recombination in RNA viruses can lead to the emergence of drug-resistant or highly virulent strains. Here, we report that host Pmr1p, an ion pump that controls Ca2+/Mn2+ influx into the Golgi from the cytosol, affects the frequency of viral RNA recombination and the efficiency of replication. Inactivation of PMR1 leads to an approximately 160-fold increase in RNA recombination of Tomato bushy stunt virus (TBSV) in yeast, a model host. Expression of separation-of-function mutants of Pmr1p reveals that the ability of Pmr1p to control the Mn2+ concentration in the cytosol is a key factor in viral RNA recombination. Indeed, a high Mn2+ concentration in a cell-free TBSV replication system increases the recombination frequency, and knockdown of Ca2+/Mn2+ exporters in plants increases virus replication and RNA recombination. Thus, a conserved host protein could affect the adaptive evolution of RNA viruses.
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Affiliation(s)
- Hannah M Jaag
- Department of Plant Pathology, University of Kentucky, Plant Science Building, Lexington, KY 40546, USA
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Defective Interfering RNAs: Foes of Viruses and Friends of Virologists. Viruses 2009; 1:895-919. [PMID: 21994575 PMCID: PMC3185524 DOI: 10.3390/v1030895] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 11/09/2009] [Accepted: 11/09/2009] [Indexed: 12/25/2022] Open
Abstract
Defective interfering (DI) RNAs are subviral RNAs produced during multiplication of RNA viruses by the error-prone viral replicase. DI-RNAs are parasitic RNAs that are derived from and associated with the parent virus, taking advantage of viral-coded protein factors for their multiplication. Recent advances in the field of DI RNA biology has led to a greater understanding about generation and evolution of DI-RNAs as well as the mechanism of symptom attenuation. Moreover, DI-RNAs are versatile tools in the hands of virologists and are used as less complex surrogate templates to understand the biology of their helper viruses. The ease of their genetic manipulation has resulted in rapid discoveries on cis-acting RNA replication elements required for replication and recombination. DI-RNAs have been further exploited to discover host factors that modulate Tomato bushy stunt virus replication, as well as viral RNA recombination. This review discusses the current models on generation and evolution of DI-RNAs, the roles of viral and host factors in DI-RNA replication, and the mechanisms of disease attenuation.
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Draghici HK, Varrelmann M. Evidence that the linker between the methyltransferase and helicase domains of potato virus X replicase is involved in homologous RNA recombination. J Virol 2009; 83:7761-9. [PMID: 19439477 PMCID: PMC2708637 DOI: 10.1128/jvi.00179-08] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 05/07/2009] [Indexed: 12/29/2022] Open
Abstract
Recombination in RNA viruses, one of the main factors contributing to their genetic variability and evolution, is a widespread phenomenon. In this study, an in vivo assay to characterize RNA recombination in potato virus X (PVX), under high selection pressure, was established. Agrobacterium tumefaciens was used to express in Nicotiana benthamiana leaf tissue both a PVX isolate labeled with green fluorescent protein (GFP) containing a coat protein deletion mutation (DeltaCP) and a transcript encoding a functional coat protein +3'-ntr. Coexpression of the constructs led to virus movement and systemic infection; reconstituted recombinants were observed in 92% of inoculated plants. Similar results were obtained using particle bombardment, demonstrating that recombination mediated by A. tumefaciens was not responsible for the occurrence of PXC recombinants. The speed of recombination could be estimated by agroinfection of two PVX mutants lacking the 3' and 5' halves of the genome, respectively, with an overlap in the triple gene block 1 gene, allowing GFP expression only in the case of recombination. Ten different pentapeptide insertion scanning replicase mutants with replication abilities comparable to wild-type virus were applied in the different recombination assays. Two neighboring mutants affecting the linker between the methyltransferase and helicase domains were shown to be strongly debilitated in their ability to recombine. The possible functional separation of replication and recombination in the replicase molecule supports the model that RNA recombination represents a distinct function of this protein, although the underlying mechanism still needs to be investigated.
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Affiliation(s)
- Heidrun-Katharina Draghici
- Department of Crop Sciences, Section Plant Virology, University of Göttingen, Grisebachstrasse 6, D-37077 Göttingen, Germany
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Liu Z, Robida JM, Chinnaswamy S, Yi G, Robotham JM, Nelson HB, Irsigler A, Kao CC, Tang H. Mutations in the hepatitis C virus polymerase that increase RNA binding can confer resistance to cyclosporine A. Hepatology 2009; 50:25-33. [PMID: 19489073 PMCID: PMC2727352 DOI: 10.1002/hep.22987] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
UNLABELLED Hepatitis C virus (HCV) infection leads to acute and chronic liver diseases, and new classes of anti-HCV therapeutics are needed. Cyclosporine A (CsA) inhibits HCV replication and CsA derivatives that lack the immunosuppressive function are currently in clinical trials as candidate anti-HCV drugs. Here we characterize several independently derived HCV replicons with varying levels of CsA resistance due to mutations in nonstructural protein 5B (NS5B), the HCV-encoded polymerase. Mutant HCV replicons engineered with these mutations showed resistance to CsA. The mutations reside in two distinct patches in the polymerase: the template channel and one face of a concave surface behind the template channel. Mutant NS5B made by cells expressing the HCV replicon had increased ability to bind to RNA in the presence of CsA. Purified recombinant NS5B proteins containing the mutations were better at de novo initiated RNA synthesis than the wild-type control. Furthermore, the mutant proteins were able to bind RNA with approximately 8-fold higher affinity. Last, mutation near the template channel alleviated the lethal phenotype of a mutation in the concave patch, P540A. This intramolecular compensation for the HCV replicase function by amino acid changes in different domains was further confirmed in an infectious cell culture-derived virus system. CONCLUSION An increased level of CsA resistance is associated with distinct mutations in the NS5B gene that increase RNA binding in the presence of CsA, and the intramolecular communications between residues of the thumb and the C-terminal domains are important for HCV replicase function.
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Affiliation(s)
- Zhe Liu
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - John M. Robida
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Sreedhar Chinnaswamy
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
| | - Guanghui Yi
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
| | - Jason M. Robotham
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Heather B. Nelson
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - Andre Irsigler
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
| | - C. Cheng Kao
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA
| | - Hengli Tang
- Department of Biological Science, Florida State University, Tallahassee, Florida 32306-4295, USA
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Impaired replication of hepatitis C virus containing mutations in a conserved NS5B retinoblastoma protein-binding motif. J Virol 2009; 83:7422-33. [PMID: 19458004 DOI: 10.1128/jvi.00262-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Hepatitis C virus (HCV) downregulates the retinoblastoma tumor suppressor protein (Rb), a central cell cycle regulator which is also targeted by oncoproteins expressed by DNA tumor viruses. HCV genome replication is also enhanced in proliferating cells. Thus, it is possible that HCV interactions with host cell cycle regulators, such as Rb, have evolved to modify the intracellular environment to promote viral replication. To test this hypothesis and to determine the impact of viral regulation of Rb on HCV replication, we constructed infectious viral genomes containing mutations in the Rb-binding motif of NS5B which ablate the ability of HCV to regulate Rb. These genomes underwent replication in transfected cells but produced variably reduced virus yields. One mutant, L314A, was severely compromised for replication and rapidly mutated to L314V, thereby restoring both Rb regulation and replication competence. Another mutant, C316A, also failed to downregulate Rb abundance and produced virus yields that were about one-third that of virus with the wild-type (wt) NS5B sequence. Despite this loss of replication competence, purified NS5B-C316A protein was two- to threefold more active than wt NS5B in cell-free polymerase and replicase assays. Although small interfering RNA knockdown of Rb did not rescue the replication fitness of these mutants, we conclude that the defect in replication fitness is not due to defective polymerase or replicase function and is more likely to result from the inability of the mutated NS5B to optimally regulate Rb abundance and thereby modulate host gene expression.
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