1
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Wu J, Bisaro DM. Cell-cell communication and initial population composition shape the structure of potato spindle tuber viroid quasispecies. THE PLANT CELL 2024; 36:1036-1055. [PMID: 38252648 PMCID: PMC10980348 DOI: 10.1093/plcell/koae012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/19/2023] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
RNA viruses and viroids replicate with high mutation rates, forming quasispecies, population of variants centered around dominant sequences. The mechanisms governing quasispecies remain unclear. Plasmodesmata regulate viroid movement and were hypothesized to impact viroid quasispecies. Here, we sequenced the progeny of potato spindle tuber viroid intermediate (PSTVd-I) strain from mature guard cells lacking plasmodesmal connections and from in vitro-cultivated mesophyll cell protoplasts from systemic leaves of early-infected tomato (Solanum lycopersicum) plants. Remarkably, more variants accumulated in guard cells compared to whole leaves. Similarly, after extended cell culture, we observed more variants in cultivated mesophyll protoplasts. Coinfection and single-cell sequencing experiments demonstrated that the same plant cell can be infected multiple times by the same or different PSTVd sequences. To study the impact of initial population composition on PSTVd-I quasispecies, we conducted coinfections with PSTVd-I and variants. Two inoculum ratios (10:1 or 1:10) established quasispecies with or without PSTVd-I as the master sequence. In the absence of the master sequence, the percentage of novel variants initially increased. Moreover, a 1:1 PSTVd-I/variant RNA ratio resulted in PSTVd-I dominating (>50%), while the variants reached 20%. After PSTVd-I-only infection, the variants reached around 10%, while after variant-only infection, the variants were significantly more than 10%. These results emphasize the role of cell-to-cell communication and initial population composition in shaping PSTVd quasispecies.
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Affiliation(s)
- Jian Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agroproducts, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
- Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA
| | - David M Bisaro
- Department of Molecular Genetics, Center for Applied Plant Sciences, Center for RNA Biology, and Infectious Diseases Institute, The Ohio State University, Columbus, OH 43210, USA
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2
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Caldwell HS, Kuo L, Pata JD, Dupuis AP, Arnold JJ, Yeager C, Stout J, Koetzner CA, Payne AF, Bialosuknia SM, Banker EM, Nolen TA, Cameron CE, Ciota AT. Maintenance of a host-specific minority mutation in the West Nile virus NS3. iScience 2023; 26:107468. [PMID: 37593454 PMCID: PMC10428113 DOI: 10.1016/j.isci.2023.107468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 06/22/2023] [Accepted: 07/21/2023] [Indexed: 08/19/2023] Open
Abstract
West Nile virus (WNV), the most prevalent arthropod-borne virus (arbovirus) in the United States, is maintained in a cycle between Culex spp. mosquitoes and birds. Arboviruses exist within hosts and vectors as a diverse set of closely related genotypes. In theory, this genetic diversity can facilitate adaptation to distinct environments during host cycling, yet host-specific fitness of minority genotypes has not been assessed. Utilizing WNV deep-sequencing data, we previously identified a naturally occurring, mosquito-biased substitution, NS3 P319L. Using both cell culture and experimental infection in natural hosts, we demonstrated that this substitution confers attenuation in vertebrate hosts and increased transmissibility by mosquitoes. Biochemical assays demonstrated temperature-sensitive ATPase activity consistent with host-specific phenotypes. Together these data confirm the maintenance of host-specific minority variants in arbovirus mutant swarms, suggest a unique role for NS3 in viral fitness, and demonstrate that intrahost sequence data can inform mechanisms of host-specific adaptation.
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Affiliation(s)
- Haley S. Caldwell
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
- Department of Biomedical Sciences, State University of New York at Albany, School of Public Health, Rensselaer, NY 12144, USA
| | - Lili Kuo
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Janice D. Pata
- Department of Biomedical Sciences, State University of New York at Albany, School of Public Health, Rensselaer, NY 12144, USA
- Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Alan P. Dupuis
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Jamie J. Arnold
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Calvin Yeager
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Jessica Stout
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Cheri A. Koetzner
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Anne F. Payne
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Sean M. Bialosuknia
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Elyse M. Banker
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Taylor A. Nolen
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
| | - Craig E. Cameron
- Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Alexander T. Ciota
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA
- Department of Biomedical Sciences, State University of New York at Albany, School of Public Health, Rensselaer, NY 12144, USA
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3
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Mutational analysis of catalytic site domain of CCHFV L RNA segment. J Mol Model 2023; 29:88. [PMID: 36877258 PMCID: PMC9987378 DOI: 10.1007/s00894-023-05487-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Accepted: 02/24/2023] [Indexed: 03/07/2023]
Abstract
INTRODUCTION Crimean-Congo haemorrhagic fever virus (CCHFV) has tripartite RNA genome and is endemic in various countries of Asia, Africa and Europe. METHOD The present study is focused on mutation profiling of CCHFV L segment and phylogenetic clustering of protein dataset into six CCHFV genotypes. RESULTS Phylogenetic tree rooted with NCBI reference sequence (YP_325663.1) indicated less divergence from genotype III and the sequences belonging to same genotypes have shown less divergence among each other. Mutation frequency at 729 mutated positions was calculated and 563, 49, 33, 46 and 38 amino acid positions were found to be mutated at mutation frequency intervals of 0-0.2, 0.21-0.4, 0.41-0.6, 0.61-0.8 and 0.81-1.0 respectively. Thirty-eight highly frequent mutations (0.81-1.0 interval) were found in all genotypes and mapping in L segment (encoded for RdRp) revealed four mutations (V2074I, I2134T/A, V2148A and Q2695H/R) in catalytic site domain and no mutation in OTU domain. Molecular dynamic simulation and in silico analysis showed that catalytic site domain displayed large deviation and fluctuation upon introduction of these point mutations. CONCLUSION Overall study provides strong evidence that OTU domain is highly conserved and less prone to mutation whereas point mutations recorded in catalytic domain have affected the stability of protein and were found to be persistent in the large population.
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4
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Caldwell HS, Pata JD, Ciota AT. The Role of the Flavivirus Replicase in Viral Diversity and Adaptation. Viruses 2022; 14:1076. [PMID: 35632818 PMCID: PMC9143365 DOI: 10.3390/v14051076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/03/2022] [Accepted: 05/06/2022] [Indexed: 02/04/2023] Open
Abstract
Flaviviruses include several emerging and re-emerging arboviruses which cause millions of infections each year. Although relatively well-studied, much remains unknown regarding the mechanisms and means by which these viruses readily alternate and adapt to different hosts and environments. Here, we review a subset of the different aspects of flaviviral biology which impact host switching and viral fitness. These include the mechanism of replication and structural biology of the NS3 and NS5 proteins, which reproduce the viral genome; rates of mutation resulting from this replication and the role of mutational frequency in viral fitness; and the theory of quasispecies evolution and how it contributes to our understanding of genetic and phenotypic plasticity.
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Affiliation(s)
- Haley S. Caldwell
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA;
- Department of Biomedical Sciences, State University of New York at Albany, School of Public Health, Rensselaer, NY 12144, USA;
| | - Janice D. Pata
- Department of Biomedical Sciences, State University of New York at Albany, School of Public Health, Rensselaer, NY 12144, USA;
- Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Alexander T. Ciota
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA;
- Department of Biomedical Sciences, State University of New York at Albany, School of Public Health, Rensselaer, NY 12144, USA;
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5
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Borrego B, Moreno S, López-Valiñas Á, de la Losa N, Weber F, Núñez JI, Brun A. Identification of Single Amino Acid Changes in the Rift Valley Fever Virus Polymerase Core Domain Contributing to Virus Attenuation In Vivo. Front Cell Infect Microbiol 2022; 12:875539. [PMID: 35573791 PMCID: PMC9096444 DOI: 10.3389/fcimb.2022.875539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 03/31/2022] [Indexed: 11/18/2022] Open
Abstract
Rift Valley fever (RVF) is an arboviral zoonotic disease affecting many African countries with the potential to spread to other geographical areas. RVF affects sheep, goats, cattle and camels, causing a high rate of abortions and death of newborn lambs. Also, humans can be infected, developing a usually self-limiting disease that can turn into a more severe illness in a low percentage of cases. Although different veterinary vaccines are available in endemic areas in Africa, to date no human vaccine has been licensed. In previous works, we described the selection and characterization of a favipiravir-mutagenized RVFV variant, termed 40Fp8, with potential as a RVF vaccine candidate due to the strong attenuation shown in immunocompromised animal models. Compared to the parental South African 56/74 viral strain, 40Fp8 displayed 7 amino acid substitutions in the L-protein, three of them located in the central region corresponding to the catalytic core of the RNA-dependent RNA polymerase (RdRp). In this work, by means of a reverse genetics system, we have analyzed the effect on virulence of these amino acid changes, alone or combined, both in vitro and in vivo. We found that the simultaneous introduction of two changes (G924S and A1303T) in the heterologous ZH548-RVFV Egyptian strain conferred attenuated phenotypes to the rescued viruses as shown in infected mice without affecting virus immunogenicity. Our results suggest that both changes induce resistance to favipiravir likely associated to some fitness cost that could be the basis for the observed attenuation in vivo. Conversely, the third change, I1050V, appears to be a compensatory mutation increasing viral fitness. Altogether, these results provide relevant information for the safety improvement of novel live attenuated RVFV vaccines.
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Affiliation(s)
- Belén Borrego
- Centro de Investigación en Sanidad Animal, CISA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (INIA/CSIC)), Madrid, Spain
- *Correspondence: Belén Borrego, ; Alejandro Brun,
| | - Sandra Moreno
- Centro de Investigación en Sanidad Animal, CISA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (INIA/CSIC)), Madrid, Spain
| | - Álvaro López-Valiñas
- Centre de Recerca en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA) Institut de Recerca en Tecnologies Agroalimentàries (IRTA), Barcelona, Spain
| | - Nuria de la Losa
- Centro de Investigación en Sanidad Animal, CISA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (INIA/CSIC)), Madrid, Spain
| | - Friedemann Weber
- Institut für Virologie, FB10-Veterinary Medicine, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - José Ignacio Núñez
- Centre de Recerca en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA) Institut de Recerca en Tecnologies Agroalimentàries (IRTA), Barcelona, Spain
| | - Alejandro Brun
- Centro de Investigación en Sanidad Animal, CISA (Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria/Consejo Superior de Investigaciones Científicas (INIA/CSIC)), Madrid, Spain
- *Correspondence: Belén Borrego, ; Alejandro Brun,
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6
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Forni D, Cagliani R, Pontremoli C, Clerici M, Sironi M. The substitution spectra of coronavirus genomes. Brief Bioinform 2022; 23:bbab382. [PMID: 34518866 PMCID: PMC8499949 DOI: 10.1093/bib/bbab382] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/23/2022] Open
Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has triggered an unprecedented international effort to sequence complete viral genomes. We leveraged this wealth of information to characterize the substitution spectrum of SARS-CoV-2 and to compare it with those of other human and animal coronaviruses. We show that, once nucleotide composition is taken into account, human and most animal coronaviruses display a mutation spectrum dominated by C to U and G to U substitutions, a feature that is not shared by other positive-sense RNA viruses. However, the proportions of C to U and G to U substitutions tend to decrease as divergence increases, suggesting that, whatever their origin, a proportion of these changes is subsequently eliminated by purifying selection. Analysis of the sequence context of C to U substitutions showed little evidence of apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC)-mediated editing and such contexts were similar for SARS-CoV-2 and Middle East respiratory syndrome coronavirus sampled from different hosts, despite different repertoires of APOBEC3 proteins in distinct species. Conversely, we found evidence that C to U and G to U changes affect CpG dinucleotides at a frequency higher than expected. Whereas this suggests ongoing selective reduction of CpGs, this effect alone cannot account for the substitution spectra. Finally, we show that, during the first months of SARS-CoV-2 pandemic spread, the frequency of both G to U and C to U substitutions increased. Our data suggest that the substitution spectrum of SARS-CoV-2 is determined by an interplay of factors, including intrinsic biases of the replication process, avoidance of CpG dinucleotides and other constraints exerted by the new host.
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Affiliation(s)
- Diego Forni
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Rachele Cagliani
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Chiara Pontremoli
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
| | - Mario Clerici
- Department of Physiopathology and Transplantation, University of Milan, Milan, Italy
- Don C. Gnocchi Foundation ONLUS, IRCCS, Milan, Italy
| | - Manuela Sironi
- Scientific Institute IRCCS E. MEDEA, Bioinformatics, Bosisio Parini, Italy
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7
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Passow KT, Caldwell HS, Ngo KA, Arnold JJ, Antczak NM, Narayanan A, Jose J, Sturla SJ, Cameron CE, Ciota AT, Harki DA. A Chemical Strategy for Intracellular Arming of an Endogenous Broad-Spectrum Antiviral Nucleotide. J Med Chem 2021; 64:15429-15439. [PMID: 34661397 DOI: 10.1021/acs.jmedchem.1c01481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The naturally occurring nucleotide 3'-deoxy-3',4'-didehydro-cytidine-5'-triphosphate (ddhCTP) was recently found to exert potent and broad-spectrum antiviral activity. However, nucleoside 5'-triphosphates in general are not cell-permeable, which precludes the direct use of ddhCTP as a therapeutic. To harness the therapeutic potential of this endogenous antiviral nucleotide, we synthesized phosphoramidate prodrug HLB-0532247 (1) and found it to result in dramatically elevated levels of ddhCTP in cells. We compared 1 and 3'-deoxy-3',4'-didehydro-cytidine (ddhC) and found that 1 more effectively reduces titers of Zika and West Nile viruses in cell culture with minimal nonspecific toxicity to host cells. We conclude that 1 is a promising antiviral agent based on a novel strategy of facilitating elevated levels of the endogenous ddhCTP antiviral nucleotide.
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Affiliation(s)
- Kellan T Passow
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Haley S Caldwell
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, New York 12144, United States.,The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12201, United States
| | - Kiet A Ngo
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12201, United States
| | - Jamie J Arnold
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nicole M Antczak
- Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
| | - Anoop Narayanan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Joyce Jose
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States.,Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Shana J Sturla
- Department of Health Sciences and Technology, ETH Zürich, Zürich 8092, Switzerland
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alexander T Ciota
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, New York 12144, United States.,The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, New York 12201, United States
| | - Daniel A Harki
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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8
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Xu X, Zhang L, Chu JTS, Wang Y, Chin AWH, Chong TH, Dai Z, Poon LLM, Cheung PPH, Huang X. A novel mechanism of enhanced transcription activity and fidelity for influenza A viral RNA-dependent RNA polymerase. Nucleic Acids Res 2021; 49:8796-8810. [PMID: 34379778 PMCID: PMC8421151 DOI: 10.1093/nar/gkab660] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/13/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
During RNA elongation, the influenza A viral (IAV) RNA-dependent RNA polymerase (RdRp) residues in the active site interact with the triphosphate moiety of nucleoside triphosphate (NTP) for catalysis. The molecular mechanisms by which they control the rate and fidelity of NTP incorporation remain elusive. Here, we demonstrated through enzymology, virology and computational approaches that the R239 and K235 in the PB1 subunit of RdRp are critical to controlling the activity and fidelity of transcription. Contrary to common beliefs that high-fidelity RdRp variants exert a slower incorporation rate, we discovered a first-of-its-kind, single lysine-to-arginine mutation on K235 exhibited enhanced fidelity and activity compared with wild-type. In particular, we employed a single-turnover NTP incorporation assay for the first time on IAV RdRp to show that K235R mutant RdRp possessed a 1.9-fold increase in the transcription activity of the cognate NTP and a 4.6-fold increase in fidelity compared to wild-type. Our all-atom molecular dynamics simulations further elucidated that the higher activity is attributed to the shorter distance between K235R and the triphosphate moiety of NTP compared with wild-type. These results provide novel insights into NTP incorporation and fidelity control mechanisms, which lay the foundation for the rational design of IAV vaccine and antiviral targets.
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Affiliation(s)
- Xinzhou Xu
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Lu Zhang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Julie Tung Sem Chu
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yuqing Wang
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Alex Wing Hong Chin
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Centre for Immunity and Infection, Hong Kong Science Park, Hong Kong, China
| | - Tin Hang Chong
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Zixi Dai
- Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
| | - Leo Lit Man Poon
- School of Public Health, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,HKU-Pasteur Research Pole, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.,Centre for Immunity and Infection, Hong Kong Science Park, Hong Kong, China
| | - Peter Pak-Hang Cheung
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.,Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong, China.,Li Ka Shing Institute of Health Sciences, Li Ka Shing Medical Sciences Building, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Xuhui Huang
- The Hong Kong University of Science and Technology-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China.,Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China
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9
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Cubas-Gaona LL, Flageul A, Courtillon C, Briand FX, Contrant M, Bougeard S, Lucas P, Quenault H, Leroux A, Keita A, Amelot M, Grasland B, Blanchard Y, Eterradossi N, Brown PA, Soubies SM. Genome Evolution of Two Genetically Homogeneous Infectious Bursal Disease Virus Strains During Passages in vitro and ex vivo in the Presence of a Mutagenic Nucleoside Analog. Front Microbiol 2021; 12:678563. [PMID: 34177862 PMCID: PMC8226269 DOI: 10.3389/fmicb.2021.678563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/14/2021] [Indexed: 11/13/2022] Open
Abstract
The avibirnavirus infectious bursal disease virus (IBDV) is responsible for a highly contagious and sometimes lethal disease of chickens (Gallus gallus). IBDV genetic variation is well-described for both field and live-attenuated vaccine strains, however, the dynamics and selection pressures behind this genetic evolution remain poorly documented. Here, genetically homogeneous virus stocks were generated using reverse genetics for a very virulent strain, rvv, and a vaccine-related strain, rCu-1. These viruses were serially passaged at controlled multiplicities of infection in several biological systems, including primary chickens B cells, the main cell type targeted by IBDV in vivo. Passages were also performed in the absence or presence of a strong selective pressure using the antiviral nucleoside analog 7-deaza-2'-C-methyladenosine (7DMA). Next Generation Sequencing (NGS) of viral genomes after the last passage in each biological system revealed that (i) a higher viral diversity was generated in segment A than in segment B, regardless 7DMA treatment and viral strain, (ii) diversity in segment B was increased by 7DMA treatment in both viruses, (iii) passaging of IBDV in primary chicken B cells, regardless of 7DMA treatment, did not select cell-culture adapted variants of rvv, preserving its capsid protein (VP2) properties, (iv) mutations in coding and non-coding regions of rCu-1 segment A could potentially associate to higher viral fitness, and (v) a specific selection, upon 7DMA addition, of a Thr329Ala substitution occurred in the viral polymerase VP1. The latter change, together with Ala270Thr change in VP2, proved to be associated with viral attenuation in vivo. These results identify genome sequences that are important for IBDV evolution in response to selection pressures. Such information will help tailor better strategies for controlling IBDV infection in chickens.
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Affiliation(s)
- Liliana L Cubas-Gaona
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Alexandre Flageul
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Céline Courtillon
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Francois-Xavier Briand
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Maud Contrant
- Viral Genetics and Biosecurity Unit (GVB), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Stephanie Bougeard
- Epidemiology, Animal Health and Welfare Unit (EPISABE), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Pierrick Lucas
- Viral Genetics and Biosecurity Unit (GVB), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Hélène Quenault
- Viral Genetics and Biosecurity Unit (GVB), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Aurélie Leroux
- Viral Genetics and Biosecurity Unit (GVB), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Alassane Keita
- Experimental Poultry Unit (SELEAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Michel Amelot
- Experimental Poultry Unit (SELEAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Béatrice Grasland
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Yannick Blanchard
- Viral Genetics and Biosecurity Unit (GVB), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Nicolas Eterradossi
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Paul Alun Brown
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
| | - Sébastien Mathieu Soubies
- Avian and Rabbit Virology, Immunology and Parasitology Unit (VIPAC), French Agency for Food, Environmental and Occupational Heath Safety (ANSES), Ploufragan, France
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10
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Development of a Genetically Stable Live Attenuated Influenza Vaccine Strain Using an Engineered High-Fidelity Viral Polymerase. J Virol 2021; 95:JVI.00493-21. [PMID: 33827947 DOI: 10.1128/jvi.00493-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 03/28/2021] [Indexed: 12/28/2022] Open
Abstract
RNA viruses demonstrate a vast range of variants, called quasispecies, due to error-prone replication by viral RNA-dependent RNA polymerase. Although live attenuated vaccines are effective in preventing RNA virus infection, there is a risk of reversal to virulence after their administration. To test the hypothesis that high-fidelity viral polymerase reduces the diversity of influenza virus quasispecies, resulting in inhibition of reversal of the attenuated phenotype, we first screened for a high-fidelity viral polymerase using serial virus passages under selection with a guanosine analog ribavirin. Consequently, we identified a Leu66-to-Val single amino acid mutation in polymerase basic protein 1 (PB1). The high-fidelity phenotype of PB1-L66V was confirmed using next-generation sequencing analysis and biochemical assays with the purified influenza viral polymerase. As expected, PB1-L66V showed at least two-times-lower mutation rates and decreased misincorporation rates, compared to the wild type (WT). Therefore, we next generated an attenuated PB1-L66V virus with a temperature-sensitive (ts) phenotype based on FluMist, a live attenuated influenza vaccine (LAIV) that can restrict virus propagation by ts mutations, and examined the genetic stability of the attenuated PB1-L66V virus using serial virus passages. The PB1-L66V mutation prevented reversion of the ts phenotype to the WT phenotype, suggesting that the high-fidelity viral polymerase could contribute to generating an LAIV with high genetic stability, which would not revert to the pathogenic virus.IMPORTANCE The LAIV currently in use is prescribed for actively immunizing individuals aged 2 to 49 years. However, it is not approved for infants and elderly individuals, who actually need it the most, because it might prolong virus propagation and cause an apparent infection in these individuals, due to their weak immune systems. Recently, reversion of the ts phenotype of the LAIV strain currently in use to a pathogenic virus was demonstrated in cultured cells. Thus, the generation of mutations associated with enhanced virulence in LAIV should be considered. In this study, we isolated a novel influenza virus strain with a Leu66-to-Val single amino acid mutation in PB1 that displayed a significantly higher fidelity than the WT. We generated a novel LAIV candidate strain harboring this mutation. This strain showed higher genetic stability and no ts phenotype reversion. Thus, our high-fidelity strain might be useful for the development of a safer LAIV.
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11
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Soria ME, García-Crespo C, Martínez-González B, Vázquez-Sirvent L, Lobo-Vega R, de Ávila AI, Gallego I, Chen Q, García-Cehic D, Llorens-Revull M, Briones C, Gómez J, Ferrer-Orta C, Verdaguer N, Gregori J, Rodríguez-Frías F, Buti M, Esteban JI, Domingo E, Quer J, Perales C. Amino Acid Substitutions Associated with Treatment Failure for Hepatitis C Virus Infection. J Clin Microbiol 2020; 58:JCM.01985-20. [PMID: 32999010 PMCID: PMC7685896 DOI: 10.1128/jcm.01985-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
Despite the high virological response rates achieved with current directly acting antiviral agents (DAAs) against hepatitis C virus (HCV), around 2% to 5% of treated patients do not achieve a sustained viral response. The identification of amino acid substitutions associated with treatment failure requires analytical designs, such as subtype-specific ultradeep sequencing (UDS) methods, for HCV characterization and patient management. Using this procedure, we have identified six highly represented amino acid substitutions (HRSs) in NS5A and NS5B of HCV, which are not bona fide resistance-associated substitutions (RAS), from 220 patients who failed therapy. They were present frequently in basal and posttreatment virus of patients who failed different DAA-based therapies. Contrary to several RAS, HRSs belong to the acceptable subset of substitutions according to the PAM250 replacement matrix. Their mutant frequency, measured by the number of deep sequencing reads within the HCV quasispecies that encode the relevant substitutions, ranged between 90% and 100% in most cases. They also have limited predicted disruptive effects on the three-dimensional structures of the proteins harboring them. Possible mechanisms of HRS origin and dominance, as well as their potential predictive value for treatment response, are discussed.
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Affiliation(s)
- María Eugenia Soria
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, Madrid, Spain
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Carlos García-Crespo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Brenda Martínez-González
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Lucía Vázquez-Sirvent
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Rebeca Lobo-Vega
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Ana Isabel de Ávila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Isabel Gallego
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Qian Chen
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Damir García-Cehic
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Meritxell Llorens-Revull
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Carlos Briones
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Centro de Astrobiología (CAB, CSIC-INTA), Torrejón de Ardoz, Madrid, Spain
| | - Jordi Gómez
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Instituto de Parasitología y Biomedicina 'López-Neyra' (CSIC), Parque Tecnológico Ciencias de la Salud, Armilla, Granada, Spain
| | - Cristina Ferrer-Orta
- Structural Biology Department, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
| | - Nuria Verdaguer
- Structural Biology Department, Institut de Biología Molecular de Barcelona CSIC, Barcelona, Spain
| | - Josep Gregori
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Roche Diagnostics, S.L., Barcelona, Spain
| | - Francisco Rodríguez-Frías
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Biochemistry and Microbiology Departments, VHIR-HUVH, Barcelona, Spain
| | - María Buti
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Juan Ignacio Esteban
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Josep Quer
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Celia Perales
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, Madrid, Spain
- Liver Unit, Internal Medicine Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
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12
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Divergent Mutational Landscapes of Consensus and Minority Genotypes of West Nile Virus Demonstrate Host and Gene-Specific Evolutionary Pressures. Genes (Basel) 2020; 11:genes11111299. [PMID: 33143358 PMCID: PMC7692055 DOI: 10.3390/genes11111299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/19/2020] [Accepted: 10/29/2020] [Indexed: 01/12/2023] Open
Abstract
Our current understanding of the natural evolution of RNA viruses comes largely from consensus level genetic analyses which ignore the diverse mutant swarms that comprise within-host viral populations. The breadth and composition of viral mutant swarms impact viral fitness and adaptation, and the capacity for swarm plasticity is likely to be particularly important for arthropod-borne viruses (arboviruses) that cycle between taxonomically divergent hosts. Despite this, characterization of the relationship between the selective pressures and genetic signatures of the mutant swarm and consensus sequences is lacking. To clarify this, we analyzed previously generated whole genome, deep-sequencing data from 548 West Nile virus samples isolated from avian tissues or mosquitoes in New York State from 1999-2018. Both consensus level (interhost) and minority level (intrahost) nucleotide and amino acid sequences were analyzed, and diversity at each position was calculated across the genome in order to assess the relationship between minority and consensus sequences for individual genes and hosts. Our results indicate that consensus sequences are an inept representation of the overall genetic diversity. Unique host and gene-specific signatures and selective pressures were identified. These data demonstrate that an accurate and comprehensive understanding of arbovirus evolution and adaptation within and between hosts requires consideration of minority genotypes.
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13
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García-Crespo C, Soria ME, Gallego I, de Ávila AI, Martínez-González B, Vázquez-Sirvent L, Gómez J, Briones C, Gregori J, Quer J, Perales C, Domingo E. Dissimilar Conservation Pattern in Hepatitis C Virus Mutant Spectra, Consensus Sequences, and Data Banks. J Clin Med 2020; 9:jcm9113450. [PMID: 33121037 PMCID: PMC7692060 DOI: 10.3390/jcm9113450] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 02/07/2023] Open
Abstract
The influence of quasispecies dynamics on long-term virus diversification in nature is a largely unexplored question. Specifically, whether intra-host nucleotide and amino acid variation in quasispecies fit the variation observed in consensus sequences or data bank alignments is unknown. Genome conservation and dynamics simulations are used for the computational design of universal vaccines, therapeutic antibodies and pan-genomic antiviral agents. The expectation is that selection of escape mutants will be limited when mutations at conserved residues are required. This strategy assumes long-term (epidemiologically relevant) conservation but, critically, does not consider short-term (quasispecies-dictated) residue conservation. We calculated mutant frequencies of individual loci from mutant spectra of hepatitis C virus (HCV) populations passaged in cell culture and from infected patients. Nucleotide or amino acid conservation in consensus sequences of the same populations, or in the Los Alamos HCV data bank did not match residue conservation in mutant spectra. The results relativize the concept of sequence conservation in viral genetics and suggest that residue invariance in data banks is an insufficient basis for the design of universal viral ligands for clinical purposes. Our calculations suggest relaxed mutational restrictions during quasispecies dynamics, which may contribute to higher calculated short-term than long-term viral evolutionary rates.
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Affiliation(s)
- Carlos García-Crespo
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
| | - María Eugenia Soria
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM. Av. Reyes Católicos 2, 28040 Madrid, Spain
| | - Isabel Gallego
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
| | - Ana Isabel de Ávila
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
| | - Brenda Martínez-González
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM. Av. Reyes Católicos 2, 28040 Madrid, Spain
| | - Lucía Vázquez-Sirvent
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
| | - Jordi Gómez
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
- Department of Molecular Biology, Instituto de Parasitología y Biomedicina ‘López-Neyra’ (CSIC), Parque Tecnológico Ciencias de la Salud, Armilla, 18016 Granada, Spain
| | - Carlos Briones
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
- Department of Molecular Evolution, Centro de Astrobiología (CAB, CSIC-INTA), Torrejón de Ardoz, 28850 Madrid, Spain
| | - Josep Gregori
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
- Liver Unit, Liver Diseases—Viral Hepatitis, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain
- Roche Diagnostics, S.L., Sant Cugat del Vallés, 08174 Barcelona, Spain
| | - Josep Quer
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
- Liver Unit, Liver Diseases—Viral Hepatitis, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Hospital Universitari, Vall d’Hebron Barcelona Hospital Campus, Passeig Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - Celia Perales
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM. Av. Reyes Católicos 2, 28040 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
- Correspondence: or (C.P.); (E.D.)
| | - Esteban Domingo
- Department of Interactions with the environment, Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain; (C.G.-C.); (M.E.S.); (I.G.); (A.I.d.Á.); (B.M.-G.); (L.V.-S.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029 Madrid, Spain; (J.G.); (C.B.); (J.G.); (J.Q.)
- Correspondence: or (C.P.); (E.D.)
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14
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Kautz TF, Jaworski E, Routh A, Forrester NL. A Low Fidelity Virus Shows Increased Recombination during the Removal of an Alphavirus Reporter Gene. Viruses 2020; 12:E660. [PMID: 32575413 PMCID: PMC7354468 DOI: 10.3390/v12060660] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 01/18/2023] Open
Abstract
Reporter genes for RNA viruses are well-known to be unstable due to putative RNA recombination events that excise inserted nucleic acids. RNA recombination has been demonstrated to be co-regulated with replication fidelity in alphaviruses, but it is unknown how recombination events at the minority variant level act, which is important for vaccine and trans-gene delivery design. Therefore, we sought to characterize the removal of a reporter gene by a low-fidelity alphavirus mutant over multiple replication cycles. To examine this, GFP was inserted into TC-83, a live-attenuated vaccine for the alphavirus Venezuelan equine encephalitis virus, as well as a low-fidelity variant of TC-83, and passaged until fluorescence was no longer observed. Short-read RNA sequencing using ClickSeq was performed to determine which regions of the viral genome underwent recombination and how this changed over multiple replication cycles. A rapid removal of the GFP gene was observed, where minority variants in the virus population accumulated small deletions that increased in size over the course of passaging. Eventually, these small deletions merged to fully remove the GFP gene. The removal was significantly enhanced during the passaging of low-fidelity TC-83, suggesting that increased levels of recombination are a defining characteristic of this mutant.
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Affiliation(s)
- Tiffany F Kautz
- Institute for Human Infections and Immunity, Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA
- Glenn Biggs Institute for Alzheimer's & Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX 78229, USA
| | - Elizabeth Jaworski
- Department of Biochemistry and Molecular Biology, University of Medical Branch, Galveston, TX 77555-0645, USA
| | - Andrew Routh
- Department of Biochemistry and Molecular Biology, University of Medical Branch, Galveston, TX 77555-0645, USA
| | - Naomi L Forrester
- Institute for Human Infections and Immunity, Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA
- School of Life Sciences, University of Keele, Keele ST5 5BG, UK
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15
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Patterson EI, Khanipov K, Swetnam DM, Walsdorf S, Kautz TF, Thangamani S, Fofanov Y, Forrester NL. Measuring Alphavirus Fidelity Using Non-Infectious Virus Particles. Viruses 2020; 12:v12050546. [PMID: 32429270 PMCID: PMC7291308 DOI: 10.3390/v12050546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/06/2020] [Accepted: 05/13/2020] [Indexed: 01/17/2023] Open
Abstract
Mutations are incorporated into the genomes of RNA viruses at an optimal frequency and altering this precise frequency has been proposed as a strategy to create live-attenuated vaccines. However, determining the effect of specific mutations that alter fidelity has been difficult because of the rapid selection of the virus population during replication. By deleting residues of the structural polyprotein PE2 cleavage site, E3Δ56-59, in Venezuelan equine encephalitis virus (VEEV) TC-83 vaccine strain, non-infectious virus particles were used to assess the effect of single mutations on mutation frequency without the interference of selection that results from multiple replication cycles. Next-generation sequencing analysis revealed a significantly lower frequency of transversion mutations and overall mutation frequency for the fidelity mutants compared to VEEV TC-83 E3Δ56-59. We demonstrate that deletion of the PE2 cleavage site halts virus infection while making the virus particles available for downstream sequencing. The conservation of the site will allow the evaluation of suspected fidelity mutants across alphaviruses of medical importance.
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Affiliation(s)
- Edward I. Patterson
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.W.); (S.T.); (N.L.F.)
- Centre for Neglected Tropical Diseases, Departments of Vector Biology and Tropical Disease Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
- Correspondence:
| | - Kamil Khanipov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA; (K.K.); (Y.F.)
| | - Daniele M. Swetnam
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616, USA;
| | - Samantha Walsdorf
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.W.); (S.T.); (N.L.F.)
| | - Tiffany F. Kautz
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Saravanan Thangamani
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.W.); (S.T.); (N.L.F.)
| | - Yuriy Fofanov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA; (K.K.); (Y.F.)
| | - Naomi L. Forrester
- Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.W.); (S.T.); (N.L.F.)
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16
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Caldwell HS, Ngo K, Pata JD, Kramer LD, Ciota AT. West Nile Virus fidelity modulates the capacity for host cycling and adaptation. J Gen Virol 2020; 101:410-419. [PMID: 32068528 DOI: 10.1099/jgv.0.001393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The fidelity of flaviviruses is thought to be tightly regulated for optimal fitness within and between hosts. West Nile virus (WNV) high-fidelity (HiFi) mutations V793I and G806R within the RNA-dependent RNA polymerase, and low-fidelity (LoFi) mutation T248I within the methyltransferase, were previously shown to attenuate infectivity and replicative fitness in Culex mosquitoes and Culex tarsalis (CXT) cells but not in mammalian cells. We hypothesized that fidelity alterations would modify adaptation and maintenance in a host-specific manner. To test this hypothesis, wild-type (WT), HiFi (V793I/G806R) and LoFi (T248I) variants were sequentially passaged eight times in avian (PDE) or mosquito cells, or alternately between the two. Initial characterization confirmed that fidelity mutants are attenuated in mosquito, but not avian, cells. Deep sequencing revealed mutations unique to both cell lines and fidelity mutants, including ENV G1378A, a mutation associated with avian cell adaptation. To characterize maintenance and adaptation, viral outputs were monitored throughout passaging and viral fitness was assessed. The results indicate that fidelity mutants can at times recover fitness during mosquito cell passage, but remain attenuated relative to WT. Despite similar initial fitness, LoFi mutants were impaired during sequential passage in avian cells. Conversely, HiFi mutants passaged in avian cells showed increased adaptation, suggesting that increased fidelity may be advantageous in avian hosts. Although some adaptation occurred with individual mutants, the output titres of fidelity mutants were on average lower and were often lost during host switching. These data confirm that arbovirus fidelity is likely fine-tuned to maximize survival in disparate hosts.
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Affiliation(s)
- Haley S Caldwell
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA.,Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA
| | - Kiet Ngo
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Janice D Pata
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA
| | - Laura D Kramer
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA.,Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA
| | - Alexander T Ciota
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA.,Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA
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Quasispecies dynamics in disease prevention and control. VIRUS AS POPULATIONS 2020. [PMCID: PMC7153035 DOI: 10.1016/b978-0-12-816331-3.00008-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Medical interventions to prevent and treat viral disease constitute evolutionary forces that may modify the genetic composition of viral populations that replicate in an infected host and influence the genomic composition of those viruses that are transmitted and progress at the epidemiological level. Given the adaptive potential of viruses in general and the RNA viruses in particular, the selection of viral mutants that display some degree of resistance to inhibitors or vaccines is a tangible challenge. Mutant selection may jeopardize control of the viral disease. Strategies intended to minimize vaccination and treatment failures are proposed and justified based on fundamental features of viral dynamics explained in the preceding chapters. The recommended use of complex, multiepitopic vaccines, and combination therapies as early as possible after initiation of infection falls under the general concept that complexity cannot be combated with simplicity. It also follows that sociopolitical action to interrupt virus replication and spread as soon as possible is as important as scientifically sound treatment designs to control viral disease on a global scale.
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Tyr82 Amino Acid Mutation in PB1 Polymerase Induces an Influenza Virus Mutator Phenotype. J Virol 2019; 93:JVI.00834-19. [PMID: 31462570 DOI: 10.1128/jvi.00834-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/19/2019] [Indexed: 01/16/2023] Open
Abstract
In various positive-sense single-stranded RNA viruses, a low-fidelity viral RNA-dependent RNA polymerase (RdRp) confers attenuated phenotypes by increasing the mutation frequency. We report a negative-sense single-stranded RNA virus RdRp mutant strain with a mutator phenotype. Based on structural data of RdRp, rational targeting of key residues, and screening of fidelity variants, we isolated a novel low-fidelity mutator strain of influenza virus that harbors a Tyr82-to-Cys (Y82C) single-amino-acid substitution in the PB1 polymerase subunit. The purified PB1-Y82C polymerase indeed showed an increased frequency of misincorporation compared with the wild-type PB1 in an in vitro biochemical assay. To further investigate the effects of position 82 on PB1 polymerase fidelity, we substituted various amino acids at this position. As a result, we isolated various novel mutators other than PB1-Y82C with higher mutation frequencies. The structural model of influenza virus polymerase complex suggested that the Tyr82 residue, which is located at the nucleoside triphosphate entrance tunnel, may influence a fidelity checkpoint. Interestingly, although the PB1-Y82C variant replicated with wild-type PB1-like kinetics in tissue culture, the 50% lethal dose of the PB1-Y82C mutant was 10 times lower than that of wild-type PB1 in embryonated chicken eggs. In conclusion, our data indicate that the Tyr82 residue of PB1 has a crucial role in regulating polymerase fidelity of influenza virus and is closely related to attenuated pathogenic phenotypes in vivo IMPORTANCE Influenza A virus rapidly acquires antigenic changes and antiviral drug resistance, which limit the effectiveness of vaccines and drug treatments, primarily owing to its high rate of evolution. Virus populations formed by quasispecies can contain resistance mutations even before a selective pressure is applied. To study the effects of the viral mutation spectrum and quasispecies, high- and low-fidelity variants have been isolated for several RNA viruses. Here, we report the discovery of a low-fidelity RdRp variant of influenza A virus that contains a substitution at Tyr82 in PB1. Viruses containing the PB1-Y82C substitution showed growth kinetics and viral RNA synthesis levels similar to those of the wild-type virus in cell culture; however, they had significantly attenuated phenotypes in a chicken egg infection experiment. These data demonstrated that decreased RdRp fidelity attenuates influenza A virus in vivo, which is a desirable feature for the development of safer live attenuated vaccine candidates.
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Bialosuknia SM, Tan Y, Zink SD, Koetzner CA, Maffei JG, Halpin RA, Mueller EA, Novotny M, Shilts M, Fedorova NB, Amedeo P, Das SR, Pickett B, Kramer LD, Ciota AT. Evolutionary dynamics and molecular epidemiology of West Nile virus in New York State: 1999-2015. Virus Evol 2019; 5:vez020. [PMID: 31341640 PMCID: PMC6642743 DOI: 10.1093/ve/vez020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Following its introduction into New York State (NYS) in 1999, West Nile virus (WNV; Flavivirus, Flaviviridae) underwent a rapid expansion throughout the USA and into Canada and Latin America. WNV has been characterized as being evolutionarily stable, with weak geographic structure, a dominance of purifying selection and limited adaptive change. We analyzed all available full-genome WNV sequences, focusing on the 543 available sequences from NYS, which included 495 newly sequenced 2000–15 isolates. In addition, we analyzed deep-sequencing data from 317 of these isolates. While our data are generally in agreement with the limited pace of evolutionary change and broad geographic and temporal mixing identified in other studies, we have identified some important exceptions. Most notably, there are 14 codons which demonstrated evidence of positive selection as determined by multiple models, including some positions with evidence of selection in NYS exclusively. Coincident with increased WNV activity, genotypes possessing one or more of these mutations, designated NY01, NY07, and NY10, have increased in prevalence in recent years and displaced historic strains. In addition, we have found a geographical bias with many of these mutations, which suggests selective pressures and adaptations could be regional. Lastly, our deep-sequencing data suggest both increased overall diversity in avian tissue isolates relative to mosquito isolates and multiple non-synonymous minority variants that are both host-specific and retained over time and space. Together, these data provide novel insight into the evolutionary pressures on WNV and the need for continued genetic surveillance and characterization of emergent strains.
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Affiliation(s)
- Sean M Bialosuknia
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Yi Tan
- Department of Medicine, Vanderbilt University Medical Center, Nashville, 1161 21st Street, Nashville, TN, USA
| | - Steven D Zink
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Cheri A Koetzner
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Joseph G Maffei
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
| | - Rebecca A Halpin
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Emmi A Mueller
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Mark Novotny
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Meghan Shilts
- Department of Medicine, Vanderbilt University Medical Center, Nashville, 1161 21st Street, Nashville, TN, USA
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Nadia B Fedorova
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Paolo Amedeo
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Suman R Das
- Department of Medicine, Vanderbilt University Medical Center, Nashville, 1161 21st Street, Nashville, TN, USA
| | - Brett Pickett
- J. Craig Venter Institute, Virology, 9605 Medical Center Drive, Rockville, MD, USA
| | - Laura D Kramer
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Rensselear, NY, USA
| | - Alexander T Ciota
- The Arbovirus Laboratory, New York State Department of Health, Wadsworth Center, 5668 State Farm Road, Slingerlands, NY, USA
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Rensselear, NY, USA
- Corresponding author: E-mail:
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Infection of Aedes albopictus Mosquito C6/36 Cells with the wMelpop Strain of Wolbachia Modulates Dengue Virus-Induced Host Cellular Transcripts and Induces Critical Sequence Alterations in the Dengue Viral Genome. J Virol 2019; 93:JVI.00581-19. [PMID: 31092581 DOI: 10.1128/jvi.00581-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/06/2019] [Indexed: 12/16/2022] Open
Abstract
Dengue virus (DENV) causes frequent epidemics infecting ∼390 million people annually in over 100 countries. There are no approved vaccines or antiviral drugs for treatment of infected patients. However, there is a novel approach to control DENV transmission by the mosquito vectors, Aedes aegypti and Aedes albopictus, using the Wolbachia symbiont. The wMelPop strain of Wolbachia suppresses DENV transmission and shortens the mosquito life span. However, the underlying mechanism is poorly understood. To clarify this mechanism, either naive A. albopictus (C6/36) or wMelPop-C6/36 cells were infected with DENV serotype 2 (DENV2). Analysis of host transcript profiles by transcriptome sequencing (RNAseq) revealed that the presence of wMelPop dramatically altered the mosquito host cell transcription in response to DENV2 infection. The viral RNA evolved from wMelPop-C6/36 cells contained low-frequency mutations (∼25%) within the coding region of transmembrane domain 1 (TMD1) of E protein. Mutations with >97% frequencies were distributed within other regions of E, the NS5 RNA-dependent RNA polymerase (NS5POL) domain, and the TMDs of NS2A, NS2B, and NS4B. Moreover, while DENV2-infected naive C6/36 cells showed syncytium formation, DENV2-infected wMelPop-C6/36 cells did not. The Wolbachia-induced mutant DENV2 can readily infect and replicate in naive C6/36 cells, whereas in mutant DENV2-infected BHK-21 or Vero cells, virus replication was delayed. In LLC-MK2 cells, the mutant failed to produce plaques. Additionally, in BHK-21 cells, many mutations in the viral genome reverted to the wild type (WT) and compensatory mutations in NS3 gene appeared. Our results indicate that wMelPop impacts significantly the interactions of DENV2 with mosquito and mammalian host cells.IMPORTANCE Mosquito-borne diseases are of global significance causing considerable morbidity and mortality throughout the world. Dengue virus (DENV; serotypes 1 to 4), a member of the Flavivirus genus of the Flaviviridae family, causes millions of infections annually. Development of a safe vaccine is hampered due to absence of cross-protection and increased risk in secondary infections due to antibody-mediated immune enhancement. Infection of vector mosquitoes with Wolbachia bacteria offers a novel countermeasure to suppress DENV transmission, but the mechanisms are poorly understood. In this study, the host transcription profiles and viral RNA sequences were analyzed in naive A. albopictus (C6/36) and wMelPop-C6/36 cells by RNAseq. Our results showed that the wMelPop symbiont caused profound changes in host transcription profiles and morphology of DENV2-infected C6/36 cells. Accumulation of several mutations throughout DENV2 RNA resulted in loss of infectivity of progeny virions. Our findings offer new insights into the mechanism of Wolbachia-mediated suppression of DENV transmission.
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Endless Forms: Within-Host Variation in the Structure of the West Nile Virus RNA Genome during Serial Passage in Bird Hosts. mSphere 2019; 4:4/3/e00291-19. [PMID: 31243074 PMCID: PMC6595145 DOI: 10.1128/msphere.00291-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The enzymes that copy RNA genomes lack proofreading, and viruses that possess RNA genomes, such as West Nile virus, rapidly diversify into swarms of mutant lineages within a host. Intrahost variation of the primary genomic sequence of RNA viruses has been studied extensively because the extent of this variation shapes key virus phenotypes. However, RNA genomes also form complex secondary structures based on within-genome nucleotide complementarity, which are critical regulators of the cyclization of the virus genome that is necessary for efficient replication and translation. We sought to characterize variation in these secondary structures within populations of West Nile virus during serial passage in three bird species. Our study indicates that the intrahost population of West Nile virus is a diverse assortment of RNA secondary structures that should be considered in future analyses of intrahost viral diversity, but some regions that are critical for genome cyclization are conserved within hosts. Besides potential impacts on viral replication, structural diversity can influence the efficacy of small RNA antiviral therapies. RNA viruses are infamous for their high rates of mutation, which produce swarms of genetic variants within individual hosts. To date, analyses of intrahost genetic diversity have focused on the primary genome sequence. However, virus phenotypes are shaped not only by primary sequence but also by the secondary structures into which this sequence folds. Such structures enable viral replication, translation, and binding of small RNAs, yet within-host variation at the structural level has not been adequately explored. We characterized the structural diversity of the 5′ untranslated region (UTR) of populations of West Nile virus (WNV) that had been subject to five serial passages in triplicate in each of three bird species. Viral genomes were sampled from host serum samples at each passage (n = 45 populations) and subjected to next-generation sequencing. For populations derived from passages 1, 3, and 5 (n = 9 populations), we predicted the impact of each mutation occurring at a frequency of ≥1% on the secondary structure of the 5′ UTR. As expected, mutations in double-stranded (DS) regions of the 5′ UTR stem structures caused structural changes of significantly greater magnitude than did mutations in single-stranded (SS) regions. Despite the greater impact of mutations in DS regions, mutations in DS and SS regions occurred at similar frequencies, with no evidence of enhanced selection against mutation in DS regions. In contrast, mutations in two regions that mediate genome cyclization and thereby regulate replication and translation, the 5′ cyclization sequence and the UAR flanking stem (UFS), were suppressed in all three hosts. IMPORTANCE The enzymes that copy RNA genomes lack proofreading, and viruses that possess RNA genomes, such as West Nile virus, rapidly diversify into swarms of mutant lineages within a host. Intrahost variation of the primary genomic sequence of RNA viruses has been studied extensively because the extent of this variation shapes key virus phenotypes. However, RNA genomes also form complex secondary structures based on within-genome nucleotide complementarity, which are critical regulators of the cyclization of the virus genome that is necessary for efficient replication and translation. We sought to characterize variation in these secondary structures within populations of West Nile virus during serial passage in three bird species. Our study indicates that the intrahost population of West Nile virus is a diverse assortment of RNA secondary structures that should be considered in future analyses of intrahost viral diversity, but some regions that are critical for genome cyclization are conserved within hosts. Besides potential impacts on viral replication, structural diversity can influence the efficacy of small RNA antiviral therapies.
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Enterovirus A71 Containing Codon-Deoptimized VP1 and High-Fidelity Polymerase as Next-Generation Vaccine Candidate. J Virol 2019; 93:JVI.02308-18. [PMID: 30996087 DOI: 10.1128/jvi.02308-18] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/31/2019] [Indexed: 12/18/2022] Open
Abstract
Enterovirus A71 (EV-A71) is a major pathogen that causes hand-foot-and-mouth disease (HFMD), which occasionally results in severe neurological complications. In this study, we developed four EV-A71 (rgEV-A71) strains by reverse genetics procedures as possible vaccine candidates. The four rgEV-A71 viruses contained various codon-deoptimized VP1 capsid proteins (VP1-CD) and showed replication rates and antigenicity similar to that of the wild-type virus, while a fifth virus, rg4643C4VP-CD, was unable to form plaques but was still able to be examined by median tissue culture infectious dose (TCID50) titers, which were similar to those of the others, indicating the effect of CD on plaque formation. However, the genome stability showed that there were some mutations which appeared during just one passage of the VP1-CD viruses. Thus, we further constructed VP1-CD rgEV-A71 containing high-fidelity determinants in 3D polymerase (CD-HF), and the number of mutations in CD-HF rgEV-A71 was shown to have decreased. The CD-HF viruses showed less virulence than the parental strain in a mouse infection model. After 14 days postimmunization, antibody titers had increased in mice infected with CD-HF viruses. The mouse antisera showed similar neutralizing antibody titers against various CD-HF viruses and different genotypes of EV-A71. The study demonstrates the proof of concept that VP1 codon deoptimization combined with high-fidelity 3D polymerase decreased EV-A71 mutations and virulence in mice but retained their antigenicity, indicating it is a good candidate for next-generation EV-A71 vaccine development.IMPORTANCE EV-A71 can cause severe neurological diseases with fatality in infants and young children, but there are still no effective drugs to date. Here, we developed a novel vaccine strategy with the combination of CD and HF substitutions to generate the genetically stable reverse genetics virus. We found that CD combined with HF polymerase decreased the virulence but maintained the antigenicity of the virus. This work demonstrated the simultaneous introduction of CD genome sequences and HF substitutions as a potential new strategy to develop attenuated vaccine seed virus. Our work provides insight into the development of a low-virulence candidate vaccine virus through a series of genetic editing of virus sequences while maintaining its antigenicity and genome stability, which will provide an additional strategy for next-generation vaccine development of EV-A71.
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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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Warmbrod KL, Patterson EI, Kautz TF, Stanton A, Rockx-Brouwer D, Kalveram BK, Khanipov K, Thangamani S, Fofanov Y, Forrester NL. Viral RNA-dependent RNA polymerase mutants display an altered mutation spectrum resulting in attenuation in both mosquito and vertebrate hosts. PLoS Pathog 2019; 15:e1007610. [PMID: 30947291 PMCID: PMC6467425 DOI: 10.1371/journal.ppat.1007610] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 04/16/2019] [Accepted: 01/31/2019] [Indexed: 02/06/2023] Open
Abstract
The presence of bottlenecks in the transmission cycle of many RNA viruses leads to a severe reduction of number of virus particles and this occurs multiple times throughout the viral transmission cycle. Viral replication is then necessary for regeneration of a diverse mutant swarm. It is now understood that any perturbation of the mutation frequency either by increasing or decreasing the accumulation of mutations in an RNA virus results in attenuation of the virus. To determine if altering the rate at which a virus accumulates mutations decreases the probability of a successful virus infection due to issues traversing host bottlenecks, a series of mutations in the RNA-dependent RNA polymerase of Venezuelan equine encephalitis virus (VEEV), strain 68U201, were tested for mutation rate changes. All RdRp mutants were attenuated in both the mosquito and vertebrate hosts, while showing no attenuation during in vitro infections. The rescued viruses containing these mutations showed some evidence of change in fidelity, but the phenotype was not sustained following passaging. However, these mutants did exhibit changes in the frequency of specific types of mutations. Using a model of mutation production, these changes were shown to decrease the number of stop codons generated during virus replication. This suggests that the observed mutant attenuation in vivo may be due to an increase in the number of unfit genomes, which may be normally selected against by the accumulation of stop codons. Lastly, the ability of these attenuated viruses to transition through a bottleneck in vivo was measured using marked virus clones. The attenuated viruses showed an overall reduction in the number of marked clones for both the mosquito and vertebrate hosts, as well as a reduced ability to overcome the known bottlenecks in the mosquito. This study demonstrates that any perturbation of the optimal mutation frequency whether through changes in fidelity or by alterations in the mutation frequency of specific nucleotides, has significant deleterious effects on the virus, especially in the presence of host bottlenecks.
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Affiliation(s)
- K. Lane Warmbrod
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Edward I. Patterson
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Tiffany F. Kautz
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Adam Stanton
- School of Computing and Mathematics, University of Keele, Keele, United Kingdom
| | - Dedeke Rockx-Brouwer
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Birte K. Kalveram
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kamil Khanipov
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Saravanan Thangamani
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Yuriy Fofanov
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Naomi L. Forrester
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
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25
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Ciota AT. The role of co-infection and swarm dynamics in arbovirus transmission. Virus Res 2019; 265:88-93. [PMID: 30879977 DOI: 10.1016/j.virusres.2019.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 02/07/2023]
Abstract
Arthropod-borne viruses (arboviruses) are transmitted by hematophagous insects, primarily mosquitoes. The geographic range and prevalence of mosquito-borne viruses and their vectors has dramatically increased over the last 50 years. As a result, the most medically important arboviurses now co-exist in many regions, resulting in an increased frequency of co-infections in hosts and vectors. In addition to concurrent infections with human pathogens, mosquito-only viruses and/or enzootic viruses not associated with human disease are ubiquitous in mosquito populations. Moreover, mosquito-borne viruses are largely RNA viruses that exist within individual hosts as a diverse and dynamic swarm of closely related genotypes. Interactions among co-infecting viruses and genotypes can have profound effects on virulence, fitness and evolution. Here, we review our understanding of how these complex interactions influence transmission of mosquito-borne viruses, focusing on the often-neglected virus interactions in the mosquito vector, and identify gaps in our knowledge that should guide future studies.
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Affiliation(s)
- Alexander T Ciota
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA; Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA.
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26
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Riemersma KK, Steiner C, Singapuri A, Coffey LL. Chikungunya Virus Fidelity Variants Exhibit Differential Attenuation and Population Diversity in Cell Culture and Adult Mice. J Virol 2019; 93:e01606-18. [PMID: 30429348 PMCID: PMC6340026 DOI: 10.1128/jvi.01606-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022] Open
Abstract
Chikungunya virus (CHIKV) is a reemerging global health threat that produces debilitating arthritis in people. Like other RNA viruses with high mutation rates, CHIKV produces populations of genetically diverse genomes within a host. While several known CHIKV mutations influence disease severity in vertebrates and transmission by mosquitoes, the role of intrahost diversity in chikungunya arthritic disease has not been studied. In this study, high- and low-fidelity CHIKV variants, previously characterized by altered in vitro population mutation frequencies, were used to evaluate how intrahost diversity influences clinical disease, CHIKV replication, and antibody neutralization in immunocompetent adult mice inoculated in the rear footpads. Both high- and low-fidelity mutations were hypothesized to attenuate CHIKV arthritic disease, replication, and neutralizing antibody levels compared to wild-type (WT) CHIKV. Unexpectedly, high-fidelity mutants elicited more severe arthritic disease than the WT despite comparable CHIKV replication, whereas a low-fidelity mutant produced attenuated disease and replication. Serum antibody developed against both high- and low-fidelity CHIKV exhibited reduced neutralization of WT CHIKV. Using next-generation sequencing (NGS), the high-fidelity mutations were demonstrated to be genetically stable but produced more genetically diverse populations than WT CHIKV in mice. This enhanced diversification was subsequently reproduced after serial in vitro passage. The NGS results contrast with previously reported population diversities for fidelity variants, which focused mainly on part of the E1 gene, and highlight the need for direct measurements of mutation rates to clarify CHIKV fidelity phenotypes.IMPORTANCE CHIKV is a reemerging global health threat that elicits debilitating arthritis in humans. There are currently no commercially available CHIKV vaccines. Like other RNA viruses, CHIKV has a high mutation rate and is capable of rapid intrahost diversification during an infection. In other RNA viruses, virus population diversity associates with disease progression; however, potential impacts of intrahost viral diversity on CHIKV arthritic disease have not been studied. Using previously characterized CHIKV fidelity variants, we addressed whether CHIKV population diversity influences the severity of arthritis and host antibody response in an arthritic mouse model. Our findings show that CHIKV populations with greater genetic diversity can cause more severe disease and stimulate antibody responses with reduced neutralization of low-diversity virus populations in vitro The discordant high-fidelity phenotypes in this study highlight the complexity of inferring replication fidelity indirectly from population diversity.
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Affiliation(s)
- Kasen K Riemersma
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Cody Steiner
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Anil Singapuri
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
| | - Lark L Coffey
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, California, USA
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27
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Ngo KA, Rose JT, Kramer LD, Ciota AT. Adaptation of Rabensburg virus (RBGV) to vertebrate hosts by experimental evolution. Virology 2018; 528:30-36. [PMID: 30554071 DOI: 10.1016/j.virol.2018.11.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/15/2018] [Accepted: 11/26/2018] [Indexed: 11/25/2022]
Abstract
Rabensburg virus (RBGV; Flaviviridae, Flavivirus) has been classified as both a novel flavivirus and a unique lineage of West Nile virus (WNV). RBGV and WNV share approximately 76% sequence homology, yet RBGV does not replicate to high viral titers within vertebrate cell lines at physiological temperatures and has not been naturally isolated from a vertebrate host. These unique genetic and biological characteristics make RBGV a viable tool to identify the genetic determinants of flavivirus infectivity and fitness in vertebrate hosts. Using experimental evolution, we characterized mutated variants of RBGV that have altered capacity for infection and replication in various cell lines. Shared genetic differences within these variants were identified throughout the genome, with a large majority found in the NS3 and NS5 genes. Our results support a role for the replication complex in host utilization and suggest that epistatic interactions likely contribute to host-specific fitness and emergence.
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Affiliation(s)
- Kiet A Ngo
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA.
| | - Joshua T Rose
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Laura D Kramer
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA; Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA
| | - Alexander T Ciota
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA; Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA
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RNA Virus Fidelity Mutants: A Useful Tool for Evolutionary Biology or a Complex Challenge? Viruses 2018; 10:v10110600. [PMID: 30388745 PMCID: PMC6267201 DOI: 10.3390/v10110600] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022] Open
Abstract
RNA viruses replicate with low fidelity due to the error-prone nature of the RNA-dependent RNA polymerase, which generates approximately one mutation per round of genome replication. Due to the large population sizes produced by RNA viruses during replication, this results in a cloud of closely related virus variants during host infection, of which small increases or decreases in replication fidelity have been shown to result in virus attenuation in vivo, but not typically in vitro. Since the discovery of the first RNA virus fidelity mutants during the mid-aughts, the field has exploded with the identification of over 50 virus fidelity mutants distributed amongst 7 RNA virus families. This review summarizes the current RNA virus fidelity mutant literature, with a focus upon the definition of a fidelity mutant as well as methods to confirm any mutational changes associated with the fidelity mutant. Due to the complexity of such a definition, in addition to reports of unstable virus fidelity phenotypes, the future translational utility of these mutants and applications for basic science are examined.
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Abstract
With the advent of advanced sequencing technology, studies of RNA viruses have shown that genetic diversity can contribute to both attenuation and virulence and the paradigm is that this is controlled by the error-prone RNA-dependent RNA polymerase (RdRp). Since wild-type yellow fever virus (YFV) strain Asibi has genetic diversity typical of a wild-type RNA virus, while 17D virus vaccine has limited diversity, it provides a unique opportunity to investigate RNA population theory in the context of a well-characterized live attenuated vaccine. Utilizing infectious clone-derived viruses, we show that genetic diversity of RNA viruses is complex and that multiple genes, including structural genes and NS2B and NS4B genes also contribute to genetic diversity. We suggest that the replication complex as a whole, rather than only RdRp, drives genetic diversity, at least for YFV. One paradigm to explain the complexity of viral RNA populations is that the low fidelity of the RNA-dependent RNA polymerase (RdRp) drives high mutation rates and consequently genetic diversity. Like most RNA viruses, wild-type yellow fever virus (YFV) replication is error-prone due to the lack of proofreading by the virus-encoded RdRp. However, there is evidence that replication of the live attenuated YF vaccine virus 17D, derived from wild-type strain Asibi, is less error-prone than wild-type RNA viruses. Recent studies comparing the genetic diversity of wild-type Asibi and 17D vaccine virus found that wild-type Asibi has the typical heterogeneous population of an RNA virus, while there is limited intra- and interpopulation variability of 17D vaccine virus. Utilizing chimeric and mutant infectious clone-derived viruses, we show that high and low genetic diversity profiles of wild-type Asibi virus and vaccine virus 17D, respectively, are multigenic. Introduction of either structural (pre-membrane and envelope) genes or NS2B or NS4B substitutions into the Asibi and 17D backbone resulted in altered variant population, nucleotide diversity, and mutation frequency compared to the parental viruses. Additionally, changes in genetic diversity of the chimeric and mutant viruses correlated with the phenotype of multiplication kinetics in human alveolar A549 cells. Overall, the paradigm that only the error-prone RdRp controls genetic diversity needs to be expanded to address the role of other genes in genetic diversity, and we hypothesize that it is the replication complex as a whole and not the RdRp alone that controls genetic diversity.
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de la Higuera I, Ferrer-Orta C, Moreno E, de Ávila AI, Soria ME, Singh K, Caridi F, Sobrino F, Sarafianos SG, Perales C, Verdaguer N, Domingo E. Contribution of a Multifunctional Polymerase Region of Foot-and-Mouth Disease Virus to Lethal Mutagenesis. J Virol 2018; 92:e01119-18. [PMID: 30068642 PMCID: PMC6158410 DOI: 10.1128/jvi.01119-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 07/23/2018] [Indexed: 01/01/2023] Open
Abstract
Viral RNA-dependent RNA polymerases (RdRps) are major determinants of high mutation rates and generation of mutant spectra that mediate RNA virus adaptability. The RdRp of the picornavirus foot-and-mouth disease virus (FMDV), termed 3D, is a multifunctional protein that includes a nuclear localization signal (NLS) in its N-terminal region. Previous studies documented that some amino acid substitutions within the NLS altered nucleotide recognition and enhanced the incorporation of the mutagenic purine analogue ribavirin in viral RNA, but the mutants tested were not viable and their response to lethal mutagenesis could not be studied. Here we demonstrate that NLS amino acid substitution M16A of FMDV serotype C does not affect infectious virus production but accelerates ribavirin-mediated virus extinction. The mutant 3D displays polymerase activity, RNA binding, and copying processivity that are similar to those of the wild-type enzyme but shows increased ribavirin-triphosphate incorporation. Crystal structures of the mutant 3D in the apo and RNA-bound forms reveal an expansion of the template entry channel due to the replacement of the bulky Met by Ala. This is a major difference with other 3D mutants with altered nucleotide analogue recognition. Remarkably, two distinct loop β9-α11 conformations distinguish 3Ds that exhibit higher or lower ribavirin incorporation than the wild-type enzyme. This difference identifies a specific molecular determinant of ribavirin sensitivity of FMDV. Comparison of several polymerase mutants indicates that different domains of the molecule can modify nucleotide recognition and response to lethal mutagenesis. The connection of this observation with current views on quasispecies adaptability is discussed.IMPORTANCE The nuclear localization signal (NLS) of the foot-and-mouth disease virus (FMDV) polymerase includes residues that modulate the sensitivity to mutagenic agents. Here we have described a viable NLS mutant with an amino acid replacement that facilitates virus extinction by ribavirin. The corresponding polymerase shows increased incorporation of ribavirin triphosphate and local structural modifications that implicate the template entry channel. Specifically, comparison of the structures of ribavirin-sensitive and ribavirin-resistant FMDV polymerases has identified loop β9-α11 conformation as a determinant of sensitivity to ribavirin mutagenesis.
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Affiliation(s)
| | - Cristina Ferrer-Orta
- Structural Biology Unit, Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Elena Moreno
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Ana Isabel de Ávila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - María Eugenia Soria
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Kamalendra Singh
- Christopher S. Bond Life Sciences Center and Department of Microbiology & Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Flavia Caridi
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Francisco Sobrino
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
| | - Stefan G Sarafianos
- Christopher S. Bond Life Sciences Center and Department of Microbiology & Immunology, School of Medicine, University of Missouri, Columbia, Missouri, USA
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
- Liver Unit, Internal Medicine, Laboratory of Malalties Hepàtiques, Vall d'Hebron Institut de Recerca-Hospital Universitari Vall d'Hebron (VHIR-HUVH), Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Nuria Verdaguer
- Structural Biology Unit, Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Barcelona, Spain
| | - Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
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Extinction of Zika Virus and Usutu Virus by Lethal Mutagenesis Reveals Different Patterns of Sensitivity to Three Mutagenic Drugs. Antimicrob Agents Chemother 2018; 62:AAC.00380-18. [PMID: 29914957 PMCID: PMC6125542 DOI: 10.1128/aac.00380-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/12/2018] [Indexed: 01/02/2023] Open
Abstract
Flaviviruses constitute an increasing source of public health concern, with growing numbers of pathogens causing disease and geographic spread to temperate climates. Despite a large body of evidence supporting mutagenesis as a conceivable antiviral strategy, there are currently no data on the sensitivity to increased mutagenesis for Zika virus (ZIKV) and Usutu virus (USUV), two emerging flaviviral threats. Flaviviruses constitute an increasing source of public health concern, with growing numbers of pathogens causing disease and geographic spread to temperate climates. Despite a large body of evidence supporting mutagenesis as a conceivable antiviral strategy, there are currently no data on the sensitivity to increased mutagenesis for Zika virus (ZIKV) and Usutu virus (USUV), two emerging flaviviral threats. In this study, we demonstrate that both viruses are sensitive to three ribonucleosides, favipiravir, ribavirin, and 5-fluorouracil, that have shown mutagenic activity against other RNA viruses while remaining unaffected by a mutagenic deoxyribonucleoside. Serial cell culture passages of ZIKV in the presence of these compounds resulted in the rapid extinction of infectivity, suggesting elevated sensitivity to mutagenesis. USUV extinction was achieved when a 10-fold dilution was applied between every passage, but not in experiments involving undiluted virus, indicating an overall lower susceptibility than ZIKV. Although the two viruses are inhibited by the same three drugs, ZIKV is relatively more susceptive to serial passage in the presence of purine analogues (favipiravir and ribavirin), while USUV replication is suppressed more efficiently by 5-fluorouracil. These differences in sensitivity typically correlate with the increases in the mutation frequencies observed in each nucleoside treatment. These results are relevant to the development of efficient therapies based on lethal mutagenesis and support the rational selection of different mutagenic nucleosides for each pathogen. We will discuss the implications of these results to the fidelity of flavivirus replication and the design of antiviral therapies based on lethal mutagenesis.
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Abstract
Live viral vaccines rely on attenuated viruses that can successfully infect their host but have reduced fitness or virulence. Such attenuated viruses were originally developed through trial and error, typically by adaptation of the wild-type virus to novel conditions. That method was haphazard, with no way of controlling the degree of attenuation or the number of attenuating mutations or preventing evolutionary reversion. Synthetic biology now enables rational design and engineering of viral attenuation, but rational design must be informed by biological principles to achieve stable, quantitative attenuation. This work shows that in a model system for viral attenuation, bacteriophage T7, attenuation can be obtained from rational design principles, and multiple different attenuation approaches can be combined for enhanced overall effect. Attenuated viruses have numerous applications, in particular in the context of live viral vaccines. However, purposefully designing attenuated viruses remains challenging, in particular if the attenuation is meant to be resistant to rapid evolutionary recovery. Here we develop and analyze a new attenuation method, promoter ablation, using an established viral model, bacteriophage T7. Ablation of promoters of the two most highly expressed T7 proteins (scaffold and capsid) led to major reductions in transcript abundance of the affected genes, with the effect of the double knockout approximately additive of the effects of single knockouts. Fitness reduction was moderate and also approximately additive; fitness recovery on extended adaptation was partial and did not restore the promoters. The fitness effect of promoter knockouts combined with a previously tested codon deoptimization of the capsid gene was less than additive, as anticipated from their competing mechanisms of action. In one design, the engineering created an unintended consequence that led to further attenuation, the effect of which was studied and understood in hindsight. Overall, the mechanisms and effects of genome engineering on attenuation behaved in a predictable manner. Therefore, this work suggests that the rational design of viral attenuation methods is becoming feasible. IMPORTANCE Live viral vaccines rely on attenuated viruses that can successfully infect their host but have reduced fitness or virulence. Such attenuated viruses were originally developed through trial and error, typically by adaptation of the wild-type virus to novel conditions. That method was haphazard, with no way of controlling the degree of attenuation or the number of attenuating mutations or preventing evolutionary reversion. Synthetic biology now enables rational design and engineering of viral attenuation, but rational design must be informed by biological principles to achieve stable, quantitative attenuation. This work shows that in a model system for viral attenuation, bacteriophage T7, attenuation can be obtained from rational design principles, and multiple different attenuation approaches can be combined for enhanced overall effect.
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Fitzsimmons WJ, Woods RJ, McCrone JT, Woodman A, Arnold JJ, Yennawar M, Evans R, Cameron CE, Lauring AS. A speed-fidelity trade-off determines the mutation rate and virulence of an RNA virus. PLoS Biol 2018; 16:e2006459. [PMID: 29953453 PMCID: PMC6040757 DOI: 10.1371/journal.pbio.2006459] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/11/2018] [Accepted: 06/12/2018] [Indexed: 11/18/2022] Open
Abstract
Mutation rates can evolve through genetic drift, indirect selection due to genetic hitchhiking, or direct selection on the physicochemical cost of high fidelity. However, for many systems, it has been difficult to disentangle the relative impact of these forces empirically. In RNA viruses, an observed correlation between mutation rate and virulence has led many to argue that their extremely high mutation rates are advantageous because they may allow for increased adaptability. This argument has profound implications because it suggests that pathogenesis in many viral infections depends on rare or de novo mutations. Here, we present data for an alternative model whereby RNA viruses evolve high mutation rates as a byproduct of selection for increased replicative speed. We find that a poliovirus antimutator, 3DG64S, has a significant replication defect and that wild-type (WT) and 3DG64S populations have similar adaptability in 2 distinct cellular environments. Experimental evolution of 3DG64S under selection for replicative speed led to reversion and compensation of the fidelity phenotype. Mice infected with 3DG64S exhibited delayed morbidity at doses well above the lethal level, consistent with attenuation by slower growth as opposed to reduced mutational supply. Furthermore, compensation of the 3DG64S growth defect restored virulence, while compensation of the fidelity phenotype did not. Our data are consistent with the kinetic proofreading model for biosynthetic reactions and suggest that speed is more important than accuracy. In contrast with what has been suggested for many RNA viruses, we find that within-host spread is associated with viral replicative speed and not standing genetic diversity. Why organisms have different mutation rates is a longstanding question in evolutionary biology. The polymerases of RNA viruses generally lack proofreading activity and exhibit extremely high mutation rates. Because most mutations are deleterious and mutation rates are typically tuned by natural selection, we asked why RNA viruses haven’t evolved a polymerase with a lower mutation rate. We used experimental evolution and a murine infection model to show that RNA virus mutation rates may actually be too high and are not necessarily adaptive. Rather, our data indicate that viral mutation rates have evolved to be higher as a result of selection for viruses with faster replication kinetics. We suggest that viruses have high mutation rates, not because they facilitate adaptation but because it is hard to be both fast and accurate and these viruses have prioritized speed over fidelity.
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Affiliation(s)
- William J. Fitzsimmons
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Robert J. Woods
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - John T. McCrone
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Andrew Woodman
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jamie J. Arnold
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Madhumita Yennawar
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Richard Evans
- Department of Epidemiology, University of Michigan, Ann Arbor, Michigan United States of America
| | - Craig E. Cameron
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Adam S. Lauring
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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A naturally occurring antiviral ribonucleotide encoded by the human genome. Nature 2018; 558:610-614. [PMID: 29925952 PMCID: PMC6026066 DOI: 10.1038/s41586-018-0238-4] [Citation(s) in RCA: 192] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 04/27/2018] [Indexed: 02/08/2023]
Abstract
Viral infections continue to represent major public health challenges, demanding enhanced mechanistic understanding of the processes contributing to viral lifecycles for the realization of new therapeutic strategies1. Viperin, a member of the radical S-adenosyl-L-methionine (SAM) superfamily of enzymes, is an interferon inducible protein implicated in inhibiting the replication of a remarkable range of RNA and DNA viruses, including dengue virus, West Nile virus, hepatitis C virus, influenza A virus, rabies virus2 and HIV3,4. Viperin has been suggested to elicit these broad antiviral activities through interactions with a large number of functionally unrelated host and viral proteins3,4. In contrast, herein, we demonstrate that viperin catalyzes the conversion of cytidine triphosphate (CTP) to 3′-deoxy-3′,4′-didehydro-CTP (ddhCTP), a previously undescribed biologically relevant molecule, via a SAM-dependent radical mechanism. We show that mammalian cells expressing viperin, and macrophages stimulated with IFN-α, produce substantial quantities of ddhCTP. We also establish that ddhCTP acts as a chain terminator for the RNA-dependent RNA-polymerases from multiple members of the flavivirus family, and present evidence that ddhCTP directly inhibits in vivo replication of ZIKA virus. These findings suggest a partially unifying mechanism, based on intrinsic catalytic/enzymatic properties, for the broad antiviral effects of viperin, which involves the generation of a naturally occurring replication chain terminator encoded by mammalian genomes.
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Kautz TF, Guerbois M, Khanipov K, Patterson EI, Langsjoen RM, Yun R, Warmbrod KL, Fofanov Y, Weaver SC, Forrester NL. Low-fidelity Venezuelan equine encephalitis virus polymerase mutants to improve live-attenuated vaccine safety and efficacy. Virus Evol 2018; 4:vey004. [PMID: 29593882 PMCID: PMC5841381 DOI: 10.1093/ve/vey004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During RNA virus replication, there is the potential to incorporate mutations that affect virulence or pathogenesis. For live-attenuated vaccines, this has implications for stability, as replication may result in mutations that either restore the wild-type phenotype via reversion or compensate for the attenuating mutations by increasing virulence (pseudoreversion). Recent studies have demonstrated that altering the mutation rate of an RNA virus is an effective attenuation tool. To validate the safety of low-fidelity mutations to increase vaccine attenuation, several mutations in the RNA-dependent RNA-polymerase (RdRp) were tested in the live-attenuated Venezuelan equine encephalitis virus vaccine strain, TC-83. Next generation sequencing after passage in the presence of mutagens revealed a mutant containing three mutations in the RdRp, TC-83 3x, to have decreased replication fidelity, while a second mutant, TC-83 4x displayed no change in fidelity, but shared many phenotypic characteristics with TC-83 3x. Both mutants exhibited increased, albeit inconsistent attenuation in an infant mouse model, as well as increased immunogenicity and complete protection against lethal challenge of an adult murine model compared with the parent TC-83. During serial passaging in a highly permissive model, the mutants increased in virulence but remained less virulent than the parent TC-83. These results suggest that the incorporation of low-fidelity mutations into the RdRp of live-attenuated vaccines for RNA viruses can confer increased immunogenicity whilst showing some evidence of increased attenuation. However, while in theory such constructs may result in more effective vaccines, the instability of the vaccine phenotype decreases the likelihood of this being an effective vaccine strategy.
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Affiliation(s)
- Tiffany F Kautz
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA
| | - Mathilde Guerbois
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Kamil Khanipov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Edward I Patterson
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Rose M Langsjoen
- Institute for Translational Sciences, University of Texas Medical Branch, Galveston, TX, USA
| | - Ruimei Yun
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Kelsey L Warmbrod
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Yuriy Fofanov
- Department of Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX, USA
| | - Scott C Weaver
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, USA.,Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Naomi L Forrester
- Department of Pathology, Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
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Li C, Wang H, Yuan T, Woodman A, Yang D, Zhou G, Cameron CE, Yu L. Foot-and-mouth disease virus type O specific mutations determine RNA-dependent RNA polymerase fidelity and virus attenuation. Virology 2018; 518:87-94. [PMID: 29455065 DOI: 10.1016/j.virol.2018.01.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/19/2018] [Accepted: 01/31/2018] [Indexed: 11/26/2022]
Abstract
Previous studies have shown that the FMDV Asia1/YS/CHA/05 high-fidelity mutagen-resistant variants are attenuated (Zeng et al., 2014). Here, we introduced the same single or multiple-amino-acid substitutions responsible for increased 3Dpol fidelity of type Asia1 FMDV into the type O FMDV O/YS/CHA/05 infectious clone. The rescued viruses O-DA and O-DAMM are lower replication fidelity mutants and showed an attenuated phenotype. These results demonstrated that the same amino acid substitution of 3Dpol in different serotypes of FMDV strains had different effects on viral fidelity. In addition, nucleoside analogues were used to select high-fidelity mutagen-resistant type O FMDV variants. The rescued mutagen-resistant type O FMDV high-fidelity variants exhibited significantly attenuated fitness and a reduced virulence phenotype. These results have important implications for understanding the molecular mechanism of FMDV evolution and pathogenicity, especially in developing a safer modified live-attenuated vaccine against FMDV.
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Affiliation(s)
- Chen Li
- Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 678 Haping Road, Xiangfang District, Harbin 150069, PR China
| | - Haiwei Wang
- Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 678 Haping Road, Xiangfang District, Harbin 150069, PR China
| | - Tiangang Yuan
- Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 678 Haping Road, Xiangfang District, Harbin 150069, PR China
| | - Andrew Woodman
- Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Decheng Yang
- Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 678 Haping Road, Xiangfang District, Harbin 150069, PR China
| | - Guohui Zhou
- Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 678 Haping Road, Xiangfang District, Harbin 150069, PR China
| | - Craig E Cameron
- Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Li Yu
- Division of Livestock Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 678 Haping Road, Xiangfang District, Harbin 150069, PR China.
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Selisko B, Papageorgiou N, Ferron F, Canard B. Structural and Functional Basis of the Fidelity of Nucleotide Selection by Flavivirus RNA-Dependent RNA Polymerases. Viruses 2018; 10:v10020059. [PMID: 29385764 PMCID: PMC5850366 DOI: 10.3390/v10020059] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 01/25/2018] [Accepted: 01/27/2018] [Indexed: 12/22/2022] Open
Abstract
Viral RNA-dependent RNA polymerases (RdRps) play a central role not only in viral replication, but also in the genetic evolution of viral RNAs. After binding to an RNA template and selecting 5'-triphosphate ribonucleosides, viral RdRps synthesize an RNA copy according to Watson-Crick base-pairing rules. The copy process sometimes deviates from both the base-pairing rules specified by the template and the natural ribose selectivity and, thus, the process is error-prone due to the intrinsic (in)fidelity of viral RdRps. These enzymes share a number of conserved amino-acid sequence strings, called motifs A-G, which can be defined from a structural and functional point-of-view. A co-relation is gradually emerging between mutations in these motifs and viral genome evolution or observed mutation rates. Here, we review our current knowledge on these motifs and their role on the structural and mechanistic basis of the fidelity of nucleotide selection and RNA synthesis by Flavivirus RdRps.
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Affiliation(s)
- Barbara Selisko
- CNRS, Aix-Marseille Université, AFMB, UMR 7257, 163 Avenue de Luminy, 13288 Marseille, France.
| | - Nicolas Papageorgiou
- CNRS, Aix-Marseille Université, AFMB, UMR 7257, 163 Avenue de Luminy, 13288 Marseille, France.
| | - François Ferron
- CNRS, Aix-Marseille Université, AFMB, UMR 7257, 163 Avenue de Luminy, 13288 Marseille, France.
| | - Bruno Canard
- CNRS, Aix-Marseille Université, AFMB, UMR 7257, 163 Avenue de Luminy, 13288 Marseille, France.
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Guo F, Li S, Caglar MU, Mao Z, Liu W, Woodman A, Arnold JJ, Wilke CO, Huang TJ, Cameron CE. Single-Cell Virology: On-Chip Investigation of Viral Infection Dynamics. Cell Rep 2017; 21:1692-1704. [PMID: 29117571 PMCID: PMC5689460 DOI: 10.1016/j.celrep.2017.10.051] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 09/05/2017] [Accepted: 10/13/2017] [Indexed: 02/05/2023] Open
Abstract
We have developed a high-throughput, microfluidics-based platform to perform kinetic analysis of viral infections in individual cells. We have analyzed thousands of individual poliovirus infections while varying experimental parameters, including multiplicity of infection, cell cycle, viral genotype, and presence of a drug. We make several unexpected observations masked by population-based experiments: (1) viral and cellular factors contribute uniquely and independently to viral infection kinetics; (2) cellular factors cause wide variation in replication start times; and (3) infections frequently begin later and replication occurs faster than predicted by population measurements. We show that mutational load impairs interaction of the viral population with the host, delaying replication start times and explaining the attenuated phenotype of a mutator virus. We show that an antiviral drug can selectively extinguish the most-fit members of the viral population. Single-cell virology facilitates discovery and characterization of virulence determinants and elucidation of mechanisms of drug action eluded by population methods.
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Affiliation(s)
- Feng Guo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sixing Li
- Molecular Cellular and Integrative Biosciences Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA
| | - Mehmet Umut Caglar
- Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, and Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Zhangming Mao
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Wu Liu
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Andrew Woodman
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Jamie J Arnold
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Claus O Wilke
- Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, and Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712, USA
| | - Tony Jun Huang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA; Molecular Cellular and Integrative Biosciences Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
| | - Craig E Cameron
- Molecular Cellular and Integrative Biosciences Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, USA; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA.
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39
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Extinction of West Nile Virus by Favipiravir through Lethal Mutagenesis. Antimicrob Agents Chemother 2017; 61:AAC.01400-17. [PMID: 28848019 DOI: 10.1128/aac.01400-17] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 08/24/2017] [Indexed: 01/12/2023] Open
Abstract
Favipiravir is an antiviral agent effective against several RNA viruses. The drug has been shown to protect mice against experimental infection with a lethal dose of West Nile virus (WNV), a mosquito-borne flavivirus responsible for outbreaks of meningitis and encephalitis for which no antiviral therapy has been licensed; however, the mechanism of action of the drug is still not well understood. Here, we describe the potent in vitro antiviral activity of favipiravir against WNV, showing that it decreases virus-specific infectivity and drives the virus to extinction. Two passages of WNV in the presence of 1 mM favipiravir-a concentration that is more than 10-fold lower than its 50% cytotoxic concentration (CC50)-resulted in a significant increase in mutation frequency in the mutant spectrum and in a bias toward A→G and G→A transitions relative to the population passaged in the absence of the drug. These data, together with the fact that the drug is already licensed in Japan against influenza virus and in a clinical trial against Ebola virus, point to favipiravir as a promising antiviral agent to fight medically relevant flaviviral infections, such as that caused by WNV.
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40
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Rawson JMO, Gohl DM, Landman SR, Roth ME, Meissner ME, Peterson TS, Hodges JS, Beckman KB, Mansky LM. Single-Strand Consensus Sequencing Reveals that HIV Type but not Subtype Significantly Impacts Viral Mutation Frequencies and Spectra. J Mol Biol 2017; 429:2290-2307. [PMID: 28502791 DOI: 10.1016/j.jmb.2017.05.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 05/07/2017] [Accepted: 05/08/2017] [Indexed: 10/19/2022]
Abstract
A long-standing question of human immunodeficiency virus (HIV) genetic variation and evolution has been whether differences exist in mutation rate and/or mutation spectra among HIV types (i.e., HIV-1 versus HIV-2) and among HIV groups (i.e., HIV-1 groups M-P and HIV-2 groups A-H) and HIV-1 Group M subtypes (i.e., subtypes A-D, F-H, and J-K). To address this, we developed a new single-strand consensus sequencing assay for the determination of HIV mutation frequencies and spectra using the Illumina sequencing platform. This assay enables parallel and standardized comparison of HIV mutagenesis among various viral vectors with lower background error than traditional methods of Illumina library preparation. We found significant differences in viral mutagenesis between HIV types but intriguingly no significant differences among HIV-1 Group M subtypes. More specifically, HIV-1 exhibited higher transition frequencies than HIV-2, due mostly to single G-to-A mutations and (to a lesser extent) G-to-A hypermutation. These data suggest that HIV-2 RT exhibits higher fidelity during viral replication, and taken together, these findings demonstrate that HIV type but not subtype significantly affects viral mutation frequencies and spectra. These differences may inform antiviral and vaccine strategies.
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Affiliation(s)
- Jonathan M O Rawson
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA; Institute for Molecular Virology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Daryl M Gohl
- University of Minnesota Genomics Center, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Sean R Landman
- Department of Computer Science and Engineering, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Megan E Roth
- Institute for Molecular Virology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Morgan E Meissner
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA; Institute for Molecular Virology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Tara S Peterson
- Institute for Molecular Virology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - James S Hodges
- Division of Biostatistics, School of Public Health, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Kenneth B Beckman
- University of Minnesota Genomics Center, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Louis M Mansky
- Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA; Institute for Molecular Virology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA; Division of Basic Sciences, School of Dentistry, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA; Department of Microbiology & Immunology, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA.
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41
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Griesemer SB, Kramer LD, Van Slyke GA, Pata JD, Gohara DW, Cameron CE, Ciota AT. Mutagen resistance and mutation restriction of St. Louis encephalitis virus. J Gen Virol 2017; 98:201-211. [PMID: 28284278 DOI: 10.1099/jgv.0.000682] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The error rate of the RNA-dependent RNA polymerase (RdRp) of RNA viruses is important in maintaining genetic diversity for viral adaptation and fitness. Numerous studies have shown that mutagen-resistant RNA virus variants display amino acid mutations in the RdRp and other replicase subunits, which in turn exhibit an altered fidelity phenotype affecting viral fitness, adaptability and pathogenicity. St. Louis encephalitis virus (SLEV), like its close relative West Nile virus, is a mosquito-borne flavivirus that has the ability to cause neuroinvasive disease in humans. Here, we describe the successful generation of multiple ribavirin-resistant populations containing a shared amino acid mutation in the SLEV RdRp (E416K). These E416K mutants also displayed resistance to the antiviral T-1106, an RNA mutagen similar to ribavirin. Structural modelling of the E416K polymerase mutation indicated its location in the pinky finger domain of the RdRp, distant from the active site. Deep sequencing of the E416K mutant revealed lower genetic diversity than wild-type SLEV after growth in both vertebrate and invertebrate cells. Phenotypic characterization showed that E416K mutants displayed similar or increased replication in mammalian cells, as well as modest attenuation in mosquito cells, consistent with previous work with West Nile virus high-fidelity variants. In addition, attenuation was limited to mosquito cells with a functional RNA interference response, suggesting an impaired capacity to escape RNA interference could contribute to attenuation of high-fidelity variants. Our results provide increased evidence that RNA mutagen resistance arises through modulation of the RdRp and give further insight into the consequences of altered fidelity of flaviviruses.
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Affiliation(s)
- Sara B Griesemer
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Laura D Kramer
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA.,The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Greta A Van Slyke
- The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Janice D Pata
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA.,The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - David W Gohara
- Department of Biochemistry and Molecular Biology, St Louis University School of Medicine, 1100 South Grand Avenue, St Louis, MO, USA
| | - Craig E Cameron
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Alexander T Ciota
- Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, NY, USA.,The Arbovirus Laboratory, Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
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42
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Smith EC. The not-so-infinite malleability of RNA viruses: Viral and cellular determinants of RNA virus mutation rates. PLoS Pathog 2017; 13:e1006254. [PMID: 28448634 PMCID: PMC5407569 DOI: 10.1371/journal.ppat.1006254] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Everett Clinton Smith
- Department of Biology, Sewanee: The University of the South, Sewanee, Tennessee, United States of America
- * E-mail:
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43
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Generation of a Genetically Stable High-Fidelity Influenza Vaccine Strain. J Virol 2017; 91:JVI.01073-16. [PMID: 28053101 DOI: 10.1128/jvi.01073-16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/24/2016] [Indexed: 12/20/2022] Open
Abstract
Vaccination is considered the most effective preventive means for influenza control. The development of a master virus with high growth and genetic stability, which may be used for the preparation of vaccine viruses by gene reassortment, is crucial for the enhancement of vaccine performance and efficiency of production. Here, we describe the generation of a high-fidelity and high-growth influenza vaccine master virus strain with a single V43I amino acid change in the PB1 polymerase of the high-growth A/Puerto Rico/8/1934 (PR8) master virus. The PB1-V43I mutation was introduced to increase replication fidelity in order to design an H1N1 vaccine strain with a low error rate. The PR8-PB1-V43I virus exhibited good replication compared with that of the parent PR8 virus. In order to compare the efficiency of egg adaptation and the occurrence of gene mutations leading to antigenic alterations, we constructed 6:2 genetic reassortant viruses between the A(H1N1)pdm09 and the PR8-PB1-V43I viruses; hemagglutinin (HA) and neuraminidase (NA) were from the A(H1N1)pdm09 virus, and the other genes were from the PR8 virus. Mutations responsible for egg adaptation mutations occurred in the HA of the PB1-V43I reassortant virus during serial egg passages; however, in contrast, antigenic mutations were introduced into the HA gene of the 6:2 reassortant virus possessing the wild-type PB1. This study shows that the mutant PR8 virus possessing the PB1 polymerase with the V43I substitution may be utilized as a master virus for the generation of high-growth vaccine viruses with high polymerase fidelity, low error rates of gene replication, and reduced antigenic diversity during virus propagation in eggs for vaccine production.IMPORTANCE Vaccination represents the most effective prophylactic option against influenza. The threat of emergence of influenza pandemics necessitates the ability to generate vaccine viruses rapidly. However, as the influenza virus exhibits a high mutation rate, vaccines must be updated to ensure a good match of the HA and NA antigens between the vaccine and the circulating strain. Here, we generated a genetically stable master virus of the A/Puerto Rico/8/1934 (H1N1) backbone encoding an engineered high-fidelity viral polymerase. Importantly, following the application of the high-fidelity PR8 backbone, no mutation resulting in antigenic change was introduced into the HA gene during propagation of the A(H1N1)pdm09 candidate vaccine virus. The low error rate of the present vaccine virus should decrease the risk of generating mutant viruses with increased virulence. Therefore, our findings are expected to be useful for the development of prepandemic vaccines and live attenuated vaccines with higher safety than that of the present candidate vaccines.
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Sanjuán R, Domingo-Calap P. Mechanisms of viral mutation. Cell Mol Life Sci 2016; 73:4433-4448. [PMID: 27392606 PMCID: PMC5075021 DOI: 10.1007/s00018-016-2299-6] [Citation(s) in RCA: 488] [Impact Index Per Article: 61.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 06/20/2016] [Accepted: 06/22/2016] [Indexed: 02/08/2023]
Abstract
The remarkable capacity of some viruses to adapt to new hosts and environments is highly dependent on their ability to generate de novo diversity in a short period of time. Rates of spontaneous mutation vary amply among viruses. RNA viruses mutate faster than DNA viruses, single-stranded viruses mutate faster than double-strand virus, and genome size appears to correlate negatively with mutation rate. Viral mutation rates are modulated at different levels, including polymerase fidelity, sequence context, template secondary structure, cellular microenvironment, replication mechanisms, proofreading, and access to post-replicative repair. Additionally, massive numbers of mutations can be introduced by some virus-encoded diversity-generating elements, as well as by host-encoded cytidine/adenine deaminases. Our current knowledge of viral mutation rates indicates that viral genetic diversity is determined by multiple virus- and host-dependent processes, and that viral mutation rates can evolve in response to specific selective pressures.
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Affiliation(s)
- Rafael Sanjuán
- Department of Genetics and Institute for Integrative Systems Biology (I2SysBio), Universitat de València, C/Catedrático José Beltrán 2, 46980, Paterna, Valencia, Spain.
| | - Pilar Domingo-Calap
- Laboratoire d'ImmunoRhumatologie Moléculaire, INSERM UMR_S1109, LabEx Transplantex, Centre de Recherche d'Immunologie et d'Hématologie, Faculté de Médecine, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg, Strasbourg, France
- Fédération Hospitalo-Universitaire OMICARE, Centre de Recherche d'Immunologie et d'Hématologie, Strasbourg, France
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45
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Dynamics of West Nile virus evolution in mosquito vectors. Curr Opin Virol 2016; 21:132-138. [PMID: 27788400 DOI: 10.1016/j.coviro.2016.09.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 01/24/2023]
Abstract
West Nile virus remains the most common cause of arboviral encephalitis in North America. Since it was introduced, it has undergone adaptive genetic change as it spread throughout the continent. The WNV transmission cycle is relatively tractable in the laboratory. Thus the virus serves as a convenient model system for studying the population biology of mosquito-borne flaviviruses as they undergo transmission to and from mosquitoes and vertebrates. This review summarizes the current knowledge regarding the population dynamics of this virus within mosquito vectors.
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46
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Sexton NR, Smith EC, Blanc H, Vignuzzi M, Peersen OB, Denison MR. Homology-Based Identification of a Mutation in the Coronavirus RNA-Dependent RNA Polymerase That Confers Resistance to Multiple Mutagens. J Virol 2016; 90:7415-7428. [PMID: 27279608 PMCID: PMC4984655 DOI: 10.1128/jvi.00080-16] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 05/27/2016] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED Positive-sense RNA viruses encode RNA-dependent RNA polymerases (RdRps) essential for genomic replication. With the exception of the large nidoviruses, such as coronaviruses (CoVs), RNA viruses lack proofreading and thus are dependent on RdRps to control nucleotide selectivity and fidelity. CoVs encode a proofreading exonuclease in nonstructural protein 14 (nsp14-ExoN), which confers a greater-than-10-fold increase in fidelity compared to other RNA viruses. It is unknown to what extent the CoV polymerase (nsp12-RdRp) participates in replication fidelity. We sought to determine whether homology modeling could identify putative determinants of nucleotide selectivity and fidelity in CoV RdRps. We modeled the CoV murine hepatitis virus (MHV) nsp12-RdRp structure and superimposed it on solved picornaviral RdRp structures. Fidelity-altering mutations previously identified in coxsackie virus B3 (CVB3) were mapped onto the nsp12-RdRp model structure and then engineered into the MHV genome with [nsp14-ExoN(+)] or without [nsp14-ExoN(-)] ExoN activity. Using this method, we identified two mutations conferring resistance to the mutagen 5-fluorouracil (5-FU): nsp12-M611F and nsp12-V553I. For nsp12-V553I, we also demonstrate resistance to the mutagen 5-azacytidine (5-AZC) and decreased accumulation of mutations. Resistance to 5-FU, and a decreased number of genomic mutations, was effectively masked by nsp14-ExoN proofreading activity. These results indicate that nsp12-RdRp likely functions in fidelity regulation and that, despite low sequence conservation, some determinants of RdRp nucleotide selectivity are conserved across RNA viruses. The results also indicate that, with regard to nucleotide selectivity, nsp14-ExoN is epistatic to nsp12-RdRp, consistent with its proposed role in a multiprotein replicase-proofreading complex. IMPORTANCE RNA viruses have evolutionarily fine-tuned replication fidelity to balance requirements for genetic stability and diversity. Responsibility for replication fidelity in RNA viruses has been attributed to the RNA-dependent RNA polymerases, with mutations in RdRps for multiple RNA viruses shown to alter fidelity and attenuate virus replication and virulence. Coronaviruses (CoVs) are the only known RNA viruses to encode a proofreading exonuclease (nsp14-ExoN), as well as other replicase proteins involved in regulation of fidelity. This report shows that the CoV RdRp (nsp12) likely functions in replication fidelity; that residue determinants of CoV RdRp nucleotide selectivity map to similar structural regions of other, unrelated RNA viral polymerases; and that for CoVs, the proofreading activity of the nsp14-ExoN is epistatic to the function of the RdRp in fidelity.
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Affiliation(s)
- Nicole R Sexton
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Everett Clinton Smith
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Hervé Blanc
- Institut Pasteur, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - Marco Vignuzzi
- Institut Pasteur, Centre National de la Recherche Scientifique UMR 3569, Paris, France
| | - Olve B Peersen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Mark R Denison
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Elizabeth B. Lamb Center for Pediatric Research, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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47
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Measurements of Intrahost Viral Diversity Are Extremely Sensitive to Systematic Errors in Variant Calling. J Virol 2016; 90:6884-95. [PMID: 27194763 DOI: 10.1128/jvi.00667-16] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/11/2016] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED With next-generation sequencing technologies, it is now feasible to efficiently sequence patient-derived virus populations at a depth of coverage sufficient to detect rare variants. However, each sequencing platform has characteristic error profiles, and sample collection, target amplification, and library preparation are additional processes whereby errors are introduced and propagated. Many studies account for these errors by using ad hoc quality thresholds and/or previously published statistical algorithms. Despite common usage, the majority of these approaches have not been validated under conditions that characterize many studies of intrahost diversity. Here, we use defined populations of influenza virus to mimic the diversity and titer typically found in patient-derived samples. We identified single-nucleotide variants using two commonly employed variant callers, DeepSNV and LoFreq. We found that the accuracy of these variant callers was lower than expected and exquisitely sensitive to the input titer. Small reductions in specificity had a significant impact on the number of minority variants identified and subsequent measures of diversity. We were able to increase the specificity of DeepSNV to >99.95% by applying an empirically validated set of quality thresholds. When applied to a set of influenza virus samples from a household-based cohort study, these changes resulted in a 10-fold reduction in measurements of viral diversity. We have made our sequence data and analysis code available so that others may improve on our work and use our data set to benchmark their own bioinformatics pipelines. Our work demonstrates that inadequate quality control and validation can lead to significant overestimation of intrahost diversity. IMPORTANCE Advances in sequencing technology have made it feasible to sequence patient-derived viral samples at a level sufficient for detection of rare mutations. These high-throughput, cost-effective methods are revolutionizing the study of within-host viral diversity. However, the techniques are error prone, and the methods commonly used to control for these errors have not been validated under the conditions that characterize patient-derived samples. Here, we show that these conditions affect measurements of viral diversity. We found that the accuracy of previously benchmarked analysis pipelines was greatly reduced under patient-derived conditions. By carefully validating our sequencing analysis using known control samples, we were able to identify biases in our method and to improve our accuracy to acceptable levels. Application of our modified pipeline to a set of influenza virus samples from a cohort study provided a realistic picture of intrahost diversity and suggested the need for rigorous quality control in such studies.
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48
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Abstract
By now, it is well established that the error rate of the RNA-dependent RNA polymerase (RdRp) that replicates RNA virus genomes is a primary driver of the mutation frequencies observed in RNA virus populations-the basis for the RNA quasispecies. Over the last 10 years, a considerable amount of work has uncovered the molecular determinants of replication fidelity in this enzyme. The isolation of high- and low-fidelity variants for several RNA viruses, in an expanding number of viral families, provides evidence that nature has optimized the fidelity to facilitate genetic diversity and adaptation, while maintaining genetic integrity and infectivity. This chapter will provide an overview of what fidelity variants tell us about RNA virus biology and how they may be used in antiviral approaches.
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Affiliation(s)
- Esteban Domingo
- Campus de Cantoblanco, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Peter Schuster
- The Santa Fe Institute, Santa Fe, NM, USA and Institut f. Theoretische Chemie, Universität Wien, Vienna, Austria
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49
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Rawson JMO, Roth ME, Xie J, Daly MB, Clouser CL, Landman SR, Reilly CS, Bonnac L, Kim B, Patterson SE, Mansky LM. Synergistic reduction of HIV-1 infectivity by 5-azacytidine and inhibitors of ribonucleotide reductase. Bioorg Med Chem 2016; 24:2410-2422. [PMID: 27117260 DOI: 10.1016/j.bmc.2016.03.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 03/18/2016] [Accepted: 03/27/2016] [Indexed: 11/29/2022]
Abstract
Although many compounds have been approved for the treatment of human immunodeficiency type-1 (HIV-1) infection, additional anti-HIV-1 drugs (particularly those belonging to new drug classes) are still needed due to issues such as long-term drug-associated toxicities, transmission of drug-resistant variants, and development of multi-class resistance. Lethal mutagenesis represents an antiviral strategy that has not yet been clinically translated for HIV-1 and is based on the use of small molecules to induce excessive levels of deleterious mutations within the viral genome. Here, we show that 5-azacytidine (5-aza-C), a ribonucleoside analog that induces the lethal mutagenesis of HIV-1, and multiple inhibitors of the enzyme ribonucleotide reductase (RNR) interact in a synergistic fashion to more effectively reduce the infectivity of HIV-1. In these drug combinations, RNR inhibitors failed to significantly inhibit the conversion of 5-aza-C to 5-aza-2'-deoxycytidine, suggesting that 5-aza-C acts primarily as a deoxyribonucleoside even in the presence of RNR inhibitors. The mechanism of antiviral synergy was further investigated for the combination of 5-aza-C and one specific RNR inhibitor, resveratrol, as this combination improved the selectivity index of 5-aza-C to the greatest extent. Antiviral synergy was found to be primarily due to the reduced accumulation of reverse transcription products rather than the enhancement of viral mutagenesis. To our knowledge, these observations represent the first demonstration of antiretroviral synergy between a ribonucleoside analog and RNR inhibitors, and encourage the development of additional ribonucleoside analogs and RNR inhibitors with improved antiretroviral activity.
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Affiliation(s)
- Jonathan M O Rawson
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA
| | - Megan E Roth
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, 515 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Jiashu Xie
- Center for Drug Design, Academic Health Center, University of Minnesota, 516 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Michele B Daly
- Emory Center for AIDS Research, Emory University, 1518 Clifton Road NE, Suite 8050, Atlanta, GA 30322, USA
| | - Christine L Clouser
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, 515 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Sean R Landman
- Department of Computer Science and Engineering, University of Minnesota, 4-192 Keller Hall, 200 Union Street SE, Minneapolis, MN 55455, USA
| | - Cavan S Reilly
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Division of Biostatistics, School of Public Health, University of Minnesota, 420 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Laurent Bonnac
- Center for Drug Design, Academic Health Center, University of Minnesota, 516 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Baek Kim
- Emory Center for AIDS Research, Emory University, 1518 Clifton Road NE, Suite 8050, Atlanta, GA 30322, USA
| | - Steven E Patterson
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Center for Drug Design, Academic Health Center, University of Minnesota, 516 Delaware Street SE, Minneapolis, MN 55455, USA
| | - Louis M Mansky
- Institute for Molecular Virology, University of Minnesota, 18-242 Moos Tower, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, 515 Delaware Street SE, Minneapolis, MN 55455, USA; Department of Microbiology and Immunology, Medical School, University of Minnesota, 689 23rd Avenue SE, Minneapolis, MN 55455, USA; Molecular, Cellular, Developmental Biology & Genetics Graduate Program, University of Minnesota, 321 Church Street SE, Minneapolis, MN 55455, USA; Center for Drug Design, Academic Health Center, University of Minnesota, 516 Delaware Street SE, Minneapolis, MN 55455, USA.
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50
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Grubaugh ND, Weger-Lucarelli J, Murrieta RA, Fauver JR, Garcia-Luna SM, Prasad AN, Black WC, Ebel GD. Genetic Drift during Systemic Arbovirus Infection of Mosquito Vectors Leads to Decreased Relative Fitness during Host Switching. Cell Host Microbe 2016; 19:481-92. [PMID: 27049584 DOI: 10.1016/j.chom.2016.03.002] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/19/2016] [Accepted: 03/07/2016] [Indexed: 11/30/2022]
Abstract
The emergence of mosquito-borne RNA viruses, such as West Nile virus (WNV), is facilitated by genetically complex virus populations within hosts. Here, we determine whether WNV enzootic (Culex tarsalis, Cx. quinquefasciatus, and Cx. pipiens) and bridge vectors (Aedes aegypti) have differential impacts on viral mutational diversity and fitness. During systemic mosquito infection, WNV faced stochastic reductions in genetic diversity that rapidly was recovered during intra-tissue population expansions. Interestingly, this intrahost selection and diversification was mosquito species dependent with Cx. tarsalis and Cx. quinquefasciatus exhibiting greater WNV divergence. However, recovered viral populations contained a preponderance of potentially deleterious mutations (i.e., high mutational load) and had lower relative fitness in avian cells compared to input virus. These findings demonstrate that the adaptive potential associated with mosquito transmission varies depending on the mosquito species and carries a significant fitness cost in vertebrates.
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Affiliation(s)
- Nathan D Grubaugh
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - James Weger-Lucarelli
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Reyes A Murrieta
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Joseph R Fauver
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Selene M Garcia-Luna
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Abhishek N Prasad
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - William C Black
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Gregory D Ebel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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