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Laguna-Castro M, Rodríguez-Moreno A, Lázaro E. Evolutionary Adaptation of an RNA Bacteriophage to Repeated Freezing and Thawing Cycles. Int J Mol Sci 2024; 25:4863. [PMID: 38732084 PMCID: PMC11084849 DOI: 10.3390/ijms25094863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 05/13/2024] Open
Abstract
Bacteriophage fitness is determined by factors influencing both their replication within bacteria and their ability to maintain infectivity between infections. The latter becomes particularly crucial under adverse environmental conditions or when host density is low. In such scenarios, the damage experienced by viral particles could lead to the loss of infectivity, which might be mitigated if the virus undergoes evolutionary optimization through replication. In this study, we conducted an evolution experiment involving bacteriophage Qβ, wherein it underwent 30 serial transfers, each involving a cycle of freezing and thawing followed by replication of the surviving viruses. Our findings show that Qβ was capable of enhancing its resistance to this selective pressure through various adaptive pathways that did not impair the virus replicative capacity. Notably, these adaptations predominantly involved mutations located within genes encoding capsid proteins. The adapted populations exhibited higher resistance levels than individual viruses isolated from them, and the latter surpassed those observed in single mutants generated via site-directed mutagenesis. This suggests potential interactions among mutants and mutations. In conclusion, our study highlights the significant role of extracellular selective pressures in driving the evolution of phages, influencing both the genetic composition of their populations and their phenotypic properties.
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Affiliation(s)
| | | | - Ester Lázaro
- Centro de Astrobiología (CAB), CSIC-INTA, Carretera de Ajalvir Km 4, 28850 Torrejón de Ardoz, Madrid, Spain; (M.L.-C.); (A.R.-M.)
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2
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Frericks N, Brown RJP, Reinecke BM, Herrmann M, Brüggemann Y, Todt D, Miskey C, Vondran FWR, Steinmann E, Pietschmann T, Sheldon J. Unraveling the dynamics of hepatitis C virus adaptive mutations and their impact on antiviral responses in primary human hepatocytes. J Virol 2024; 98:e0192123. [PMID: 38319104 PMCID: PMC10949430 DOI: 10.1128/jvi.01921-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/12/2024] [Indexed: 02/07/2024] Open
Abstract
Hepatitis C virus (HCV) infection progresses to chronicity in the majority of infected individuals. Its high intra-host genetic variability enables HCV to evade the continuous selection pressure exerted by the host, contributing to persistent infection. Utilizing a cell culture-adapted HCV population (p100pop) which exhibits increased replicative capacity in various liver cell lines, this study investigated virus and host determinants that underlie enhanced viral fitness. Characterization of a panel of molecular p100 clones revealed that cell culture adaptive mutations optimize a range of virus-host interactions, resulting in expanded cell tropism, altered dependence on the cellular co-factor micro-RNA 122 and increased rates of virus spread. On the host side, comparative transcriptional profiling of hepatoma cells infected either with p100pop or its progenitor virus revealed that enhanced replicative fitness correlated with activation of endoplasmic reticulum stress signaling and the unfolded protein response. In contrast, infection of primary human hepatocytes with p100pop led to a mild attenuation of virion production which correlated with a greater induction of cell-intrinsic antiviral defense responses. In summary, long-term passage experiments in cells where selective pressure from innate immunity is lacking improves multiple virus-host interactions, enhancing HCV replicative fitness. However, this study further indicates that HCV has evolved to replicate at low levels in primary human hepatocytes to minimize innate immune activation, highlighting that an optimal balance between replicative fitness and innate immune induction is key to establish persistence. IMPORTANCE Hepatitis C virus (HCV) infection remains a global health burden with 58 million people currently chronically infected. However, the detailed molecular mechanisms that underly persistence are incompletely defined. We utilized a long-term cell culture-adapted HCV, exhibiting enhanced replicative fitness in different human liver cell lines, in order to identify molecular principles by which HCV optimizes its replication fitness. Our experimental data revealed that cell culture adaptive mutations confer changes in the host response and usage of various host factors. The latter allows functional flexibility at different stages of the viral replication cycle. However, increased replicative fitness resulted in an increased activation of the innate immune system, which likely poses boundary for functional variation in authentic hepatocytes, explaining the observed attenuation of the adapted virus population in primary hepatocytes.
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Affiliation(s)
- Nicola Frericks
- Institute for Experimental Virology, TWINCORE, Hannover, Germany
- Department for Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
| | - Richard J. P. Brown
- Department for Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
- Division of Veterinary Medicine, Paul Ehrlich Institute, Langen, Germany
| | | | - Maike Herrmann
- Division of Veterinary Medicine, Paul Ehrlich Institute, Langen, Germany
| | - Yannick Brüggemann
- Department for Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
| | - Daniel Todt
- Department for Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
| | - Csaba Miskey
- Division of Medical Biotechnology, Paul Ehrlich Institute, Langen, Germany
| | - Florian W. R. Vondran
- Department for General, Visceral and Transplant Surgery, Hannover Medical School, Hannover, Germany
- Clinic for General, Visceral and Transplant Surgery, University Hospital RWTH Aachen, Aachen, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany
| | - Eike Steinmann
- Department for Molecular and Medical Virology, Ruhr-University Bochum, Bochum, Germany
| | - Thomas Pietschmann
- Institute for Experimental Virology, TWINCORE, Hannover, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Julie Sheldon
- Institute for Experimental Virology, TWINCORE, Hannover, Germany
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3
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Domingo E, Witzany G. Quasispecies productivity. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2024; 111:11. [PMID: 38372790 DOI: 10.1007/s00114-024-01897-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/05/2024] [Accepted: 02/06/2024] [Indexed: 02/20/2024]
Abstract
The quasispecies theory is a helpful concept in the explanation of RNA virus evolution and behaviour, with a relevant impact on methods used to fight viral diseases. It has undergone some adaptations to integrate new empirical data, especially the non-deterministic nature of mutagenesis, and the variety of behavioural motifs in cooperation, competition, communication, innovation, integration, and exaptation. Also, the consortial structure of quasispecies with complementary roles of memory genomes of minority populations better fits the empirical data than did the original concept of a master sequence and its mutant spectra. The high productivity of quasispecies variants generates unique sequences that never existed before and will never exist again. In the present essay, we underline that such sequences represent really new ontological entities, not just error copies of previous ones. Their primary unique property, the incredible variant production, is suggested here as quasispecies productivity, which replaces the error-replication narrative to better fit into a new relationship between mankind and living nature in the twenty-first century.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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4
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Domingo E, García-Crespo C, Soria ME, Perales C. Viral Fitness, Population Complexity, Host Interactions, and Resistance to Antiviral Agents. Curr Top Microbiol Immunol 2023; 439:197-235. [PMID: 36592247 DOI: 10.1007/978-3-031-15640-3_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Fitness of viruses has become a standard parameter to quantify their adaptation to a biological environment. Fitness determinations for RNA viruses (and some highly variable DNA viruses) meet with several uncertainties. Of particular interest are those that arise from mutant spectrum complexity, absence of population equilibrium, and internal interactions among components of a mutant spectrum. Here, concepts, fitness measurements, limitations, and current views on experimental viral fitness landscapes are discussed. The effect of viral fitness on resistance to antiviral agents is covered in some detail since it constitutes a widespread problem in antiviral pharmacology, and a challenge for the design of effective antiviral treatments. Recent evidence with hepatitis C virus suggests the operation of mechanisms of antiviral resistance additional to the standard selection of drug-escape mutants. The possibility that high replicative fitness may be the driver of such alternative mechanisms is considered. New broad-spectrum antiviral designs that target viral fitness may curtail the impact of drug-escape mutants in treatment failures. We consider to what extent fitness-related concepts apply to coronaviruses and how they may affect strategies for COVID-19 prevention and treatment.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain.
| | - Carlos García-Crespo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - María Eugenia Soria
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos 2, 28040, Madrid, Spain
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos 2, 28040, Madrid, Spain.,Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain
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Šimičić P, Židovec-Lepej S. A Glimpse on the Evolution of RNA Viruses: Implications and Lessons from SARS-CoV-2. Viruses 2022; 15:1. [PMID: 36680042 PMCID: PMC9866536 DOI: 10.3390/v15010001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
RNA viruses are characterised by extremely high genetic variability due to fast replication, large population size, low fidelity, and (usually) a lack of proofreading mechanisms of RNA polymerases leading to high mutation rates. Furthermore, viral recombination and reassortment may act as a significant evolutionary force among viruses contributing to greater genetic diversity than obtainable by mutation alone. The above-mentioned properties allow for the rapid evolution of RNA viruses, which may result in difficulties in viral eradication, changes in virulence and pathogenicity, and lead to events such as cross-species transmissions, which are matters of great interest in the light of current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemics. In this review, we aim to explore the molecular mechanisms of the variability of viral RNA genomes, emphasising the evolutionary trajectory of SARS-CoV-2 and its variants. Furthermore, the causes and consequences of coronavirus variation are explored, along with theories on the origin of human coronaviruses and features of emergent RNA viruses in general. Finally, we summarise the current knowledge on the circulating variants of concern and highlight the many unknowns regarding SARS-CoV-2 pathogenesis.
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Affiliation(s)
| | - Snježana Židovec-Lepej
- Department of Immunological and Molecular Diagnostics, University Hospital for Infectious Diseases “Dr. Fran Mihaljević”, HR-10000 Zagreb, Croatia
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6
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Delgado S, Perales C, García-Crespo C, Soria ME, Gallego I, de Ávila AI, Martínez-González B, Vázquez-Sirvent L, López-Galíndez C, Morán F, Domingo E. A Two-Level, Intramutant Spectrum Haplotype Profile of Hepatitis C Virus Revealed by Self-Organized Maps. Microbiol Spectr 2021; 9:e0145921. [PMID: 34756074 PMCID: PMC8579923 DOI: 10.1128/spectrum.01459-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/12/2021] [Indexed: 12/17/2022] Open
Abstract
RNA viruses replicate as complex mutant spectra termed viral quasispecies. The frequency of each individual genome in a mutant spectrum depends on its rate of generation and its relative fitness in the replicating population ensemble. The advent of deep sequencing methodologies allows for the first-time quantification of haplotype abundances within mutant spectra. There is no information on the haplotype profile of the resident genomes and how the landscape evolves when a virus replicates in a controlled cell culture environment. Here, we report the construction of intramutant spectrum haplotype landscapes of three amplicons of the NS5A-NS5B coding region of hepatitis C virus (HCV). Two-dimensional (2D) neural networks were constructed for 44 related HCV populations derived from a common clonal ancestor that was passaged up to 210 times in human hepatoma Huh-7.5 cells in the absence of external selective pressures. The haplotype profiles consisted of an extended dense basal platform, from which a lower number of protruding higher peaks emerged. As HCV increased its adaptation to the cells, the number of haplotype peaks within each mutant spectrum expanded, and their distribution shifted in the 2D network. The results show that extensive HCV replication in a monotonous cell culture environment does not limit HCV exploration of sequence space through haplotype peak movements. The landscapes reflect dynamic variation in the intramutant spectrum haplotype profile and may serve as a reference to interpret the modifications produced by external selective pressures or to compare with the landscapes of mutant spectra in complex in vivo environments. IMPORTANCE The study provides for the first time the haplotype profile and its variation in the course of virus adaptation to a cell culture environment in the absence of external selective constraints. The deep sequencing-based self-organized maps document a two-layer haplotype distribution with an ample basal platform and a lower number of protruding peaks. The results suggest an inferred intramutant spectrum fitness landscape structure that offers potential benefits for virus resilience to mutational inputs.
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Affiliation(s)
- Soledad Delgado
- Departamento de Sistemas Informáticos, Escuela Técnica Superior de Ingeniería de Sistemas Informáticos (ETSISI), Universidad Politécnica de Madrid, Madrid, Spain
| | - Celia Perales
- Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD), Madrid, 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), Instituto de Salud Carlos III, Madrid, Spain
| | - Carlos García-Crespo
- 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), Instituto de Salud Carlos III, Madrid, Spain
| | - María Eugenia Soria
- Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD), Madrid, 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), Instituto de Salud Carlos III, 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), Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Isabel de Ávila
- 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), Instituto de Salud Carlos III, Madrid, Spain
| | - Brenda Martínez-González
- Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Lucía Vázquez-Sirvent
- Department of Clinical Microbiology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
| | - Cecilio López-Galíndez
- Unidad de Virología Molecular, Laboratorio de Referencia e Investigación en Retrovirus, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Federico Morán
- Departamento de Bioquímica y Biología Molecular, Universidad Complutense de Madrid, 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), Instituto de Salud Carlos III, Madrid, Spain
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Lanahan MR, Maples RW, Pfeiffer JK. Tradeoffs for a viral mutant with enhanced replication speed. Proc Natl Acad Sci U S A 2021; 118:e2105288118. [PMID: 34282021 PMCID: PMC8325337 DOI: 10.1073/pnas.2105288118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
RNA viruses exist as genetically heterogeneous populations due to high mutation rates, and many of these mutations reduce fitness and/or replication speed. However, it is unknown whether mutations can increase replication speed of a virus already well adapted to replication in cultured cells. By sequentially passaging coxsackievirus B3 in cultured cells and collecting the very earliest progeny, we selected for increased replication speed. We found that a single mutation in a viral capsid protein, VP1-F106L, was sufficient for the fast-replication phenotype. Characterization of this mutant revealed quicker genome release during entry compared to wild-type virus, highlighting a previously unappreciated infection barrier. However, this mutation also reduced capsid stability in vitro and reduced replication and pathogenesis in mice. These results reveal a tradeoff between overall replication speed and fitness. Importantly, this approach-selecting for the earliest viral progeny-could be applied to a variety of viral systems and has the potential to reveal unanticipated inefficiencies in viral replication cycles.
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Affiliation(s)
- Matthew R Lanahan
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048
| | - Robert W Maples
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048
| | - Julie K Pfeiffer
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048
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8
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Intra-Population Competition during Adaptation to Increased Temperature in an RNA Bacteriophage. Int J Mol Sci 2021; 22:ijms22136815. [PMID: 34202838 PMCID: PMC8268601 DOI: 10.3390/ijms22136815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 06/17/2021] [Accepted: 06/22/2021] [Indexed: 01/21/2023] Open
Abstract
Evolution of RNA bacteriophages of the family Leviviridae is governed by the high error rates of their RNA-dependent RNA polymerases. This fact, together with their large population sizes, leads to the generation of highly heterogeneous populations that adapt rapidly to most changes in the environment. Throughout adaptation, the different mutants that make up a viral population compete with each other in a non-trivial process in which their selective values change over time due to the generation of new mutations. In this work we have characterised the intra-population dynamics of a well-studied levivirus, Qβ, when it is propagated at a higher-than-optimal temperature. Our results show that adapting populations experienced rapid changes that involved the ascent of particular genotypes and the loss of some beneficial mutations of early generation. Artificially reconstructed populations, containing a fraction of the diversity present in actual populations, fixed mutations more rapidly, illustrating how population bottlenecks may guide the adaptive pathways. The conclusion is that, when the availability of beneficial mutations under a particular selective condition is elevated, the final outcome of adaptation depends more on the occasional occurrence of population bottlenecks and how mutations combine in genomes than on the selective value of particular mutations.
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9
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Liu J, Liu Y, Shan C, Nunes BTD, Yun R, Haller SL, Rafael GH, Azar SR, Andersen CR, Plante K, Vasilakis N, Shi PY, Weaver SC. Role of mutational reversions and fitness restoration in Zika virus spread to the Americas. Nat Commun 2021; 12:595. [PMID: 33500409 PMCID: PMC7838395 DOI: 10.1038/s41467-020-20747-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 12/15/2020] [Indexed: 01/30/2023] Open
Abstract
Zika virus (ZIKV) emerged from obscurity in 2013 to spread from Asia to the South Pacific and the Americas, where millions of people were infected, accompanied by severe disease including microcephaly following congenital infections. Phylogenetic studies have shown that ZIKV evolved in Africa and later spread to Asia, and that the Asian lineage is responsible for the recent epidemics in the South Pacific and Americas. However, the reasons for the sudden emergence of ZIKV remain enigmatic. Here we report evolutionary analyses that revealed four mutations, which occurred just before ZIKV introduction to the Americas, represent direct reversions of previous mutations that accompanied earlier spread from Africa to Asia and early circulation there. Our experimental infections of Aedes aegypti mosquitoes, human cells, and mice using ZIKV strains with and without these mutations demonstrate that the original mutations reduced fitness for urban, human-amplifed transmission, while the reversions restored fitness, increasing epidemic risk. These findings include characterization of three transmission-adaptive ZIKV mutations, and demonstration that these and one identified previously restored fitness for epidemic transmission soon before introduction into the Americas. The initial mutations may have followed founder effects and/or drift when the virus was introduced decades ago into Asia.
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Affiliation(s)
- Jianying Liu
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Yang Liu
- Department of Biochemistry and Molecular Biology and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Chao Shan
- Department of Biochemistry and Molecular Biology and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Bruno T D Nunes
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará State, Brazil
| | - Ruimei Yun
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Sherry L Haller
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Grace H Rafael
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Sasha R Azar
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Clark R Andersen
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Kenneth Plante
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Nikos Vasilakis
- Department of Pathology, Center for Biodefense and Emerging Infectious Diseases, World Reference Center for Emerging Viruses and Arboviruses, and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology and Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, 77555, USA.
| | - Scott C Weaver
- World Reference Center for Emerging Viruses and Arboviruses, Institute for Human Infections and Immunity, and Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX, 77555, USA.
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10
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They are what you eat: Shaping of viral populations through nutrition and consequences for virulence. PLoS Pathog 2020; 16:e1008711. [PMID: 32790755 PMCID: PMC7425860 DOI: 10.1371/journal.ppat.1008711] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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11
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Abstract
Viral quasispecies refers to a population structure that consists of extremely large numbers of variant genomes, termed mutant spectra, mutant swarms or mutant clouds. Fueled by high mutation rates, mutants arise continually, and they change in relative frequency as viral replication proceeds. The term quasispecies was adopted from a theory of the origin of life in which primitive replicons) consisted of mutant distributions, as found experimentally with present day RNA viruses. The theory provided a new definition of wild type, and a conceptual framework for the interpretation of the adaptive potential of RNA viruses that contrasted with classical studies based on consensus sequences. Standard clonal analyses and deep sequencing methodologies have confirmed the presence of myriads of mutant genomes in viral populations, and their participation in adaptive processes. The quasispecies concept applies to any biological entity, but its impact is more evident when the genome size is limited and the mutation rate is high. This is the case of the RNA viruses, ubiquitous in our biosphere, and that comprise many important pathogens. In virology, quasispecies are defined as complex distributions of closely related variant genomes subjected to genetic variation, competition and selection, and that may act as a unit of selection. Despite being an integral part of their replication, high mutation rates have an upper limit compatible with inheritable information. Crossing such a limit leads to RNA virus extinction, a transition that is the basis of an antiviral design termed lethal mutagenesis.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
| | - Celia Perales
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, Madrid, Spain
- Department of Clinical Microbiology, IIS-Fundación Jiménez Díaz, UAM, Madrid, Spain
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12
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Extracellular vesicles: Vehicles of en bloc viral transmission. Virus Res 2019; 265:143-149. [PMID: 30928427 DOI: 10.1016/j.virusres.2019.03.023] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 03/25/2019] [Indexed: 12/31/2022]
Abstract
En Bloc transmission of viruses allow multiple genomes to collectivelly penetrate and initiate infection in the same cell, often resulting in enhanced infectivity. Given the quasispecies (mutant cloud) nature of RNA viruses and many DNA viruses, en bloc transmission of multiple genomes provides different starting points in sequence space to initiate adaptive walks, and has implications for modulation of viral fitness and for the response of viral populations to lethal mutagenesis. Mechanisms that can enable multiple viral genomes to be transported en bloc among hosts has only recently been gaining attention. A growing body of research suggests that extracellular vesicles (EV) are highly prevalent and robust vehicles for en bloc delivery of viral particles and naked infectious genomes among organisms. Both RNA and DNA viruses appear to exploit these vesicles to increase their multiplicity of infection and enhance virulence.
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13
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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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14
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Domingo E, Perales C. Quasispecies and virus. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:443-457. [PMID: 29397419 DOI: 10.1007/s00249-018-1282-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 01/11/2018] [Accepted: 01/27/2018] [Indexed: 12/13/2022]
Abstract
Quasispecies theory has been instrumental in the understanding of RNA virus population dynamics because it considered for the first time mutation as an integral part of the replication process. The key influences of quasispecies theory on experimental virology have been: (1) to disclose the mutant spectrum nature of viral populations and to evaluate its consequences; (2) to unveil collective properties of genome ensembles that can render a mutant spectrum a unit of selection; and (3) to identify new vulnerability points of pathogenic RNA viruses on three fronts: the need to apply multiple selective constraints (in the form of drug combinations) to minimize selection of treatment-escape variants, to translate the error threshold concept into antiviral designs, and to construct attenuated vaccine viruses through alterations of viral polymerase copying fidelity or through displacements of viral genomes towards unfavorable regions of sequence space. These three major influences on the understanding of viral pathogens preceded extensions of quasispecies to non-viral systems such as bacterial and tumor cell collectivities and prions. These developments are summarized here.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain. .,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Madrid, Spain.
| | - Celia Perales
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Consejo Superior de Investigaciones Científicas (CSIC), Campus de Cantoblanco, 28049, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Madrid, 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, 08035, Barcelona, Spain
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15
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Erickson AK, Jesudhasan PR, Mayer MJ, Narbad A, Winter SE, Pfeiffer JK. Bacteria Facilitate Enteric Virus Co-infection of Mammalian Cells and Promote Genetic Recombination. Cell Host Microbe 2018; 23:77-88.e5. [PMID: 29290575 PMCID: PMC5764776 DOI: 10.1016/j.chom.2017.11.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/25/2017] [Accepted: 11/15/2017] [Indexed: 01/12/2023]
Abstract
RNA viruses exist in genetically diverse populations due to high levels of mutations, many of which reduce viral fitness. Interestingly, intestinal bacteria can promote infection of several mammalian enteric RNA viruses, but the mechanisms and consequences are unclear. We screened a panel of 41 bacterial strains as a platform to determine how different bacteria impact infection of poliovirus, a model enteric virus. Most bacterial strains, including those extracted from cecal contents of mice, bound poliovirus, with each bacterium binding multiple virions. Certain bacterial strains increased viral co-infection of mammalian cells even at a low virus-to-host cell ratio. Bacteria-mediated viral co-infection correlated with bacterial adherence to cells. Importantly, bacterial strains that induced viral co-infection facilitated genetic recombination between two different viruses, thereby removing deleterious mutations and restoring viral fitness. Thus, bacteria-virus interactions may increase viral fitness through viral recombination at initial sites of infection, potentially limiting abortive infections.
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Affiliation(s)
- Andrea K Erickson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA
| | - Palmy R Jesudhasan
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA
| | - Melinda J Mayer
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UA, UK
| | - Arjan Narbad
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UA, UK
| | - Sebastian E Winter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA
| | - Julie K Pfeiffer
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9048, USA.
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16
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Arribas M, Aguirre J, Manrubia S, Lázaro E. Differences in adaptive dynamics determine the success of virus variants that propagate together. Virus Evol 2018; 4:vex043. [PMID: 29340211 PMCID: PMC5761584 DOI: 10.1093/ve/vex043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Virus fitness is a complex parameter that results from the interaction of virus-specific characters (e.g. intracellular growth rate, adsorption rate, virion extracellular stability, and tolerance to mutations) with others that depend on the underlying fitness landscape and the internal structure of the whole population. Individual mutants usually have lower fitness values than the complex population from which they come from. When they are propagated and allowed to attain large population sizes for a sufficiently long time, they approach mutation-selection equilibrium with the concomitant fitness gains. The optimization process follows dynamics that vary among viruses, likely due to differences in any of the parameters that determine fitness values. As a consequence, when different mutants spread together, the number of generations experienced by each of them prior to co-propagation may determine its particular fate. In this work we attempt a clarification of the effect of different levels of population diversity in the outcome of competition dynamics. To this end, we analyze the behavior of two mutants of the RNA bacteriophage Qβ that co-propagate with the wild-type virus. When both competitor viruses are clonal, the mutants rapidly outcompete the wild type. However, the outcome in competitions performed with partially optimized virus populations depends on the distance of the competitors to their clonal origin. We also implement a theoretical population dynamics model that describes the evolution of a heterogeneous population of individuals, each characterized by a fitness value, subjected to subsequent cycles of replication and mutation. The experimental results are explained in the framework of our theoretical model under two non-excluding, likely complementary assumptions: (1) The relative advantage of both competitors changes as populations approach mutation-selection equilibrium, as a consequence of differences in their growth rates and (2) one of the competitors is more robust to mutations than the other. The main conclusion is that the nearness of an RNA virus population to mutation-selection equilibrium is a key factor determining the fate of particular mutants arising during replication.
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Affiliation(s)
- María Arribas
- Centro de Astrobiología (CSIC-INTA), Ctra. de Ajalvir km. 4, Torrejón de Ardoz, Madrid 28850, Spain
| | - Jacobo Aguirre
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain.,Centro Nacional de Biotecnología (CSIC), c/Darwin 3, Madrid 28049, Spain
| | - Susanna Manrubia
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain.,Centro Nacional de Biotecnología (CSIC), c/Darwin 3, Madrid 28049, Spain
| | - Ester Lázaro
- Centro de Astrobiología (CSIC-INTA), Ctra. de Ajalvir km. 4, Torrejón de Ardoz, Madrid 28850, Spain.,Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain
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17
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Catalán P, Arias CF, Cuesta JA, Manrubia S. Adaptive multiscapes: an up-to-date metaphor to visualize molecular adaptation. Biol Direct 2017; 12:7. [PMID: 28245845 PMCID: PMC5331743 DOI: 10.1186/s13062-017-0178-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 02/11/2017] [Indexed: 01/08/2023] Open
Abstract
Background Wright’s metaphor of the fitness landscape has shaped and conditioned our view of the adaptation of populations for almost a century. Since its inception, and including criticism raised by Wright himself, the concept has been surrounded by controversy. Among others, the debate stems from the intrinsic difficulty to capture important features of the space of genotypes, such as its high dimensionality or the existence of abundant ridges, in a visually appealing two-dimensional picture. Two additional currently widespread observations come to further constrain the applicability of the original metaphor: the very skewed distribution of phenotype sizes (which may actively prevent, due to entropic effects, the achievement of fitness maxima), and functional promiscuity (i.e. the existence of secondary functions which entail partial adaptation to environments never encountered before by the population). Results Here we revise some of the shortcomings of the fitness landscape metaphor and propose a new “scape” formed by interconnected layers, each layer containing the phenotypes viable in a given environment. Different phenotypes within a layer are accessible through mutations with selective value, while neutral mutations cause displacements of populations within a phenotype. A different environment is represented as a separated layer, where phenotypes may have new fitness values, other phenotypes may be viable, and the same genotype may yield a different phenotype, representing genotypic promiscuity. This scenario explicitly includes the many-to-many structure of the genotype-to-phenotype map. A number of empirical observations regarding the adaptation of populations in the light of adaptive multiscapes are reviewed. Conclusions Several shortcomings of Wright’s visualization of fitness landscapes can be overcome through adaptive multiscapes. Relevant aspects of population adaptation, such as neutral drift, functional promiscuity or environment-dependent fitness, as well as entropic trapping and the concomitant impossibility to reach fitness peaks are visualized at once. Adaptive multiscapes should aid in the qualitative understanding of the multiple pathways involved in evolutionary dynamics. Reviewers This article was reviewed by Eugene Koonin and Ricard Solé.
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Affiliation(s)
- Pablo Catalán
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain.,Departamento de Matemáticas, Universidad Carlos III de Madrid, Madrid, Spain
| | - Clemente F Arias
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain
| | - Jose A Cuesta
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain.,Departamento de Matemáticas, Universidad Carlos III de Madrid, Madrid, Spain.,Institute for Biocomputation and Physics of Complex Systems, Zaragoza, Spain.,UC3M-BS Institute of Financial Big Data (IFiBiD), Madrid, Spain
| | - Susanna Manrubia
- Grupo Interdisciplinar de Sistemas Complejos (GISC), Madrid, Spain. .,National Biotechnology Centre (CSIC), c/ Darwin 3, Madrid, 28049, Spain.
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18
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Cervera H, Elena SF. Genetic variation in fitness within a clonal population of a plant RNA virus. Virus Evol 2016; 2:vew006. [PMID: 27774299 PMCID: PMC4989883 DOI: 10.1093/ve/vew006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/11/2016] [Accepted: 02/16/2016] [Indexed: 01/01/2023] Open
Abstract
A long-standing observation in evolutionary virology is that RNA virus populations are highly polymorphic, composed by a mixture of genotypes whose abundances in the population depend on complex interaction between fitness differences, mutational coupling and genetic drift. It was shown long ago, though in cell cultures, that most of these genotypes had lower fitness than the population they belong, an observation that explained why single-virion passages turned on Muller’s ratchet while very large population passages resulted in fitness increases in novel environments. Here we report the results of an experiment specifically designed to evaluate in vivo the fitness differences among the subclonal components of a clonal population of the plant RNA virus tobacco etch potyvirus (TEV). Over 100 individual biological subclones from a TEV clonal population well adapted to the natural tobacco host were obtained by infectivity assays on a local lesion host. The replicative fitness of these subclones was then evaluated during infection of tobacco relative to the fitness of large random samples taken from the starting clonal population. Fitness was evaluated at increasing number of days post-inoculation. We found that at early days, the average fitness of subclones was significantly lower than the fitness of the clonal population, thus confirming previous observations that most subclones contained deleterious mutations. However, as the number of days of viral replication increases, population size expands exponentially, more beneficial and compensatory mutations are produced, and selection becomes more effective in optimizing fitness, the differences between subclones and the population disappeared.
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Affiliation(s)
- Héctor Cervera
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, Campus UPV CPI 8E, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
| | - Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, Campus UPV CPI 8E, Ingeniero Fausto Elio s/n, 46022 Valencia, Spain; The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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19
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Choudhury MA, Lott WB, Banu S, Cheng AY, Teo YY, Ong RTH, Aaskov J. Nature and Extent of Genetic Diversity of Dengue Viruses Determined by 454 Pyrosequencing. PLoS One 2015; 10:e0142473. [PMID: 26566128 PMCID: PMC4643897 DOI: 10.1371/journal.pone.0142473] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 10/22/2015] [Indexed: 12/23/2022] Open
Abstract
Dengue virus (DENV) populations are characteristically highly diverse. Regular lineage extinction and replacement is an important dynamic DENV feature, and most DENV lineage turnover events are associated with increased incidence of disease. The role of genetic diversity in DENV lineage extinctions is not understood. We investigated the nature and extent of genetic diversity in the envelope (E) gene of DENV serotype 1 representing different lineages histories. A region of the DENV genome spanning the E gene was amplified and sequenced by Roche/454 pyrosequencing. The pyrosequencing results identified distinct sub-populations (haplotypes) for each DENV-1 E gene. A phylogenetic tree was constructed with the consensus DENV-1 E gene nucleotide sequences, and the sequences of each constructed haplotype showed that the haplotypes segregated with the Sanger consensus sequence of the population from which they were drawn. Haplotypes determined through pyrosequencing identified a recombinant DENV genome that could not be identified through Sanger sequencing. Nucleotide level sequence diversities of DENV-1 populations determined from SNP analysis were very low, estimated from 0.009–0.01. There were also no stop codon, frameshift or non-frameshift mutations observed in the E genes of any lineage. No significant correlations between the accumulation of deleterious mutations or increasing genetic diversity and lineage extinction were observed (p>0.5). Although our hypothesis that accumulation of deleterious mutations over time led to the extinction and replacement of DENV lineages was ultimately not supported by the data, our data does highlight the significant technical issues that must be resolved in the way in which population diversity is measured for DENV and other viruses. The results provide an insight into the within-population genetic structure and diversity of DENV-1 populations.
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Affiliation(s)
- Md Abu Choudhury
- Menzies Health Institute Queensland, Griffith University, Brisbane, Australia
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- * E-mail:
| | - William B Lott
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
- School of Chemistry, Physics, and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia
| | - Shahera Banu
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Anthony Youzhi Cheng
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Yik-Ying Teo
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
- Department of Statistics and Applied Probability, National University of Singapore, Singapore, Singapore
- Life Sciences Institute, National University of Singapore, Singapore, Singapore
- Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore, Singapore
| | - Rick Twee-Hee Ong
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - John Aaskov
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
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20
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Fahnøe U, Pedersen AG, Dräger C, Orton RJ, Blome S, Höper D, Beer M, Rasmussen TB. Creation of Functional Viruses from Non-Functional cDNA Clones Obtained from an RNA Virus Population by the Use of Ancestral Reconstruction. PLoS One 2015; 10:e0140912. [PMID: 26485566 PMCID: PMC4613144 DOI: 10.1371/journal.pone.0140912] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/01/2015] [Indexed: 02/05/2023] Open
Abstract
RNA viruses have the highest known mutation rates. Consequently it is likely that a high proportion of individual RNA virus genomes, isolated from an infected host, will contain lethal mutations and be non-functional. This is problematic if the aim is to clone and investigate high-fitness, functional cDNAs and may also pose problems for sequence-based analysis of viral evolution. To address these challenges we have performed a study of the evolution of classical swine fever virus (CSFV) using deep sequencing and analysis of 84 full-length cDNA clones, each representing individual genomes from a moderately virulent isolate. In addition to here being used as a model for RNA viruses generally, CSFV has high socioeconomic importance and remains a threat to animal welfare and pig production. We find that the majority of the investigated genomes are non-functional and only 12% produced infectious RNA transcripts. Full length sequencing of cDNA clones and deep sequencing of the parental population identified substitutions important for the observed phenotypes. The investigated cDNA clones were furthermore used as the basis for inferring the sequence of functional viruses. Since each unique clone must necessarily be the descendant of a functional ancestor, we hypothesized that it should be possible to produce functional clones by reconstructing ancestral sequences. To test this we used phylogenetic methods to infer two ancestral sequences, which were then reconstructed as cDNA clones. Viruses rescued from the reconstructed cDNAs were tested in cell culture and pigs. Both reconstructed ancestral genomes proved functional, and displayed distinct phenotypes in vitro and in vivo. We suggest that reconstruction of ancestral viruses is a useful tool for experimental and computational investigations of virulence and viral evolution. Importantly, ancestral reconstruction can be done even on the basis of a set of sequences that all correspond to non-functional variants.
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Affiliation(s)
- Ulrik Fahnøe
- DTU National Veterinary Institute, Technical University of Denmark, Lindholm, Kalvehave, Denmark
- Center for Biological Sequence Analysis, DTU Systems Biology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Anders Gorm Pedersen
- Center for Biological Sequence Analysis, DTU Systems Biology, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Carolin Dräger
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Richard J Orton
- Institute of Biodiversity, Animal Health, and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- MRC–University of Glasgow Centre for Virus Research, Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sandra Blome
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Dirk Höper
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Thomas Bruun Rasmussen
- DTU National Veterinary Institute, Technical University of Denmark, Lindholm, Kalvehave, Denmark
- * E-mail:
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21
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Abstract
New generation sequencing is greatly expanding the capacity to examine the composition of mutant spectra of viral quasispecies in infected cells and host organisms. Here we review recent progress in the understanding of quasispecies dynamics, notably the occurrence of intra-mutant spectrum interactions, and implications of fitness landscapes for virus adaptation and de-adaptation. Complementation or interference can be established among components of the same mutant spectrum, dependent on the mutational status of the ensemble. Replicative fitness relates to an optimal mutant spectrum that provides the molecular basis for phenotypic flexibility, with implications for antiviral therapy. The biological impact of viral fitness renders particularly relevant the capacity of new generation sequencing to establish viral fitness landscapes. Progress with experimental model systems is becoming an important asset to understand virus behavior in the more complex environments faced during natural infections.
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22
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Choudhury MA, Lott WB, Aaskov J. Distribution of fitness in populations of dengue viruses. PLoS One 2014; 9:e107264. [PMID: 25222471 PMCID: PMC4164612 DOI: 10.1371/journal.pone.0107264] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 08/11/2014] [Indexed: 11/22/2022] Open
Abstract
Genetically diverse RNA viruses like dengue viruses (DENVs) segregate into multiple, genetically distinct, lineages that temporally arise and disappear on a regular basis. Lineage turnover may occur through multiple processes such as, stochastic or due to variations in fitness. To determine the variation of fitness, we measured the distribution of fitness within DENV populations and correlated it with lineage extinction and replacement. The fitness of most members within a population proved lower than the aggregate fitness of populations from which they were drawn, but lineage replacement events were not associated with changes in the distribution of fitness. These data provide insights into variations in fitness of DENV populations, extending our understanding of the complexity between members of individual populations.
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Affiliation(s)
- Md Abu Choudhury
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - William B Lott
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia; School of Chemistry, Physics, and Mechanical Engineering, Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, Australia
| | - John Aaskov
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
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23
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Abstract
ABSTRACT: RNA viruses replicate their genomes with very high error rates, which leads to the generation of a large genetic diversity that makes them highly adaptable to most environmental pressures, including antiviral drugs and immune responses. However, since most mutations are deleterious, an excess of errors can be very negative for RNA viruses, entailing that error rates must be finely regulated. Currently, the manipulation of the error rate is emerging as a promising antiviral therapy that could minimize the problem of virus adaptation to classical treatments. This review provides a detailed analysis of the different outcomes that can result from the variation of the error rate in RNA viruses, on the basis of the more relevant findings obtained in experimental studies.
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24
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Ciota AT, Payne AF, Ngo KA, Kramer LD. Consequences of in vitro host shift for St. Louis encephalitis virus. J Gen Virol 2014; 95:1281-1288. [PMID: 24643879 DOI: 10.1099/vir.0.063545-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Understanding the potential for host range shifts and expansions of RNA viruses is critical to predicting the evolutionary and epidemiological paths of these pathogens. As arthropod-borne viruses (arboviruses) experience frequent spillover from their amplification cycles and are generalists by nature, they are likely to experience a relatively high frequency of success in a range of host environments. Despite this, the potential for host expansion, the genetic correlates of adaptation to novel environments and the costs of such adaptations in originally competent hosts are still not characterized fully for arboviruses. In the studies presented here, we utilized experimental evolution of St. Louis encephalitis virus (SLEV; family Flaviviridae, genus Flavivirus) in vitro in the Dermacentor andersoni line of tick cells to model adaptation to a novel invertebrate host. Our results demonstrated that levels of adaptation and costs in alternate hosts are highly variable among lineages, but also that significant fitness increases in tick cells are achievable with only modest change in consensus genetic sequence. In addition, although accumulation of diversity may at times buffer against phenotypic costs within the SLEV swarm, an increased proportion of variants with an impaired capacity to infect and spread on vertebrate cell culture accumulated with tick cell passage. Isolation and characterization of a subset of these variants implicates the NS3 gene as an important host range determinant for SLEV.
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Affiliation(s)
- Alexander T Ciota
- Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Anne F Payne
- Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Kiet A Ngo
- Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
| | - Laura D Kramer
- School of Public Health, State University of New York at Albany, Albany, NY, USA.,Wadsworth Center, New York State Department of Health, Slingerlands, NY, USA
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25
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Congruent evolution of fitness and genetic robustness in vesicular stomatitis virus. J Virol 2013; 87:4923-8. [PMID: 23408631 DOI: 10.1128/jvi.02796-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Quasispecies theory is a case of mutation-selection balance for evolution at high mutation rates, such as those observed in RNA viruses. One of the main predictions of this model is the selection for robustness, defined as the ability of an organism to remain phenotypically unchanged in the face of mutation. We have used a collection of vesicular stomatitis virus strains that had been evolving either under positive selection or under random drift. We had previously shown that the former increase in fitness while the latter have overall fitness decreases (I. S. Novella, J. B. Presloid, T. Zhou, S. D. Smith-Tsurkan, B. E. Ebendick-Corpus, R. N. Dutta, K. L. Lust, and C. O. Wilke, J. Virol. 84:4960-4968, 2010). Here, we determined the robustness of these strains and demonstrated that strains under positive selection not only increase in fitness but also increase in robustness. In contrast, strains under drift not only decreased in fitness but also decreased in robustness. There was a good overall correlation between fitness and robustness. We also tested whether there was a correlation between fitness and thermostability, and we observed that the correlation was imperfect, indicating that the fitness effects of mutations are exerted in part at a level other than changing the resistance of the protein to temperature.
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26
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Smith-Tsurkan SD, Herr RA, Khuder S, Wilke CO, Novella IS. The role of environmental factors on the evolution of phenotypic diversity in vesicular stomatitis virus populations. J Gen Virol 2012; 94:860-868. [PMID: 23239575 DOI: 10.1099/vir.0.048082-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Virus adaptation to an ever-changing environment requires the availability of variants with phenotypes that can fulfil new requirements for replication. High mutation rates result in the generation of these variants. The factors that contribute to the maintenance or elimination of this diversity, however, are not fully understood. This study used a collection of vesicular stomatitis virus strains generated under different conditions to measure the extent of variation within each population, and tested the effects of several environmental factors on diversity. It was found that the host-cell type used for selection sometimes had an effect on the extent of variation and that there may be different levels of variation over time. Persistent infections promoted higher levels of diversity than acute infections, presumably due to complementation. In contrast, environmental heterogeneity, host breadth and the cell type used for testing (as opposed to the cell type used for selection) did not seem to have an effect on the amount of phenotypic diversity observed.
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Affiliation(s)
- Sarah D Smith-Tsurkan
- Department of Medical Microbiology and Immunology, College of Medicine, University of Toledo Health Science Campus, Toledo, OH, USA
| | - Roger A Herr
- Department of Medical Microbiology and Immunology, College of Medicine, University of Toledo Health Science Campus, Toledo, OH, USA
| | - Sadik Khuder
- Department of Medicine, College of Medicine, University of Toledo Health Science Campus, Toledo, OH, USA
| | - Claus O Wilke
- Center for Computational Biology and Bioinformatics, Section of Integrative Biology, and Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX, USA
| | - Isabel S Novella
- Department of Medical Microbiology and Immunology, College of Medicine, University of Toledo Health Science Campus, Toledo, OH, USA
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Jaramillo N, Domingo E, Muñoz-Egea MC, Tabarés E, Gadea I. Evidence of Muller's ratchet in herpes simplex virus type 1. J Gen Virol 2012; 94:366-375. [PMID: 23100362 DOI: 10.1099/vir.0.044685-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Population bottlenecks can have major effects in the evolution of RNA viruses, but their possible influence in the evolution of DNA viruses is largely unknown. Genetic and biological variation of herpes simplex virus type 1 (HSV-1) has been studied by subjecting 23 biological clones of the virus to 10 plaque-to-plaque transfers. In contrast to large population passages, plaque transfers led to a decrease in replicative capacity of HSV-1. Two out of a total of 23 clones did not survive to the last transfer in 143 TK(-) cells. DNA from three genomic regions (DNA polymerase, glycoprotein gD and thymidine kinase) from the initial and passaged clones was sequenced. Nucleotide substitutions were detected in the TK and gD genes, but not in the DNA polymerase gene. Assuming a uniform distribution of mutations along the genome, the average rate of fixation of mutations was about five mutations per viral genome and plaque transfer. This value is comparable to the range of values calculated for RNA viruses. Four plaque-transferred populations lost neurovirulence for mice, as compared with the corresponding initial clones. LD(50) values obtained with the populations subjected to serial bottlenecks were 4- to 67-fold higher than for their parental clones. These results equate HSV-1 with RNA viruses regarding fitness decrease as a result of plaque-to-plaque transfers, and show that population bottlenecks can modify the pathogenic potential of HSV-1. Implications for the evolution of complex DNA viruses are discussed.
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Affiliation(s)
- Nacarí Jaramillo
- Departamento de Medicina Preventiva Salud Pública y Microbiología, Facultad de Medicina, UAM, Madrid, Spain
| | - Esteban Domingo
- Centro de Investigación en Red de Enfermedades Hepáticas y Digestivas (CIBER ehd), Barcelona, Spain.,Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid) Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | | | - Enrique Tabarés
- Departamento de Medicina Preventiva Salud Pública y Microbiología, Facultad de Medicina, UAM, Madrid, Spain
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Abstract
A new word, phylodynamics, was coined to emphasize the interconnection between phylogenetic properties, as observed for instance in a phylogenetic tree, and the epidemic dynamics of viruses, where selection, mediated by the host immune response, and transmission play a crucial role. The challenges faced when investigating the evolution of RNA viruses call for a virtuous loop of data collection, data analysis and modeling. This already resulted both in the collection of massive sequences databases and in the formulation of hypotheses on the main mechanisms driving qualitative differences observed in the (reconstructed) evolutionary patterns of different RNA viruses. Qualitatively, it has been observed that selection driven by the host immune response induces an uneven survival ability among co-existing strains. As a consequence, the imbalance level of the phylogenetic tree is manifestly more pronounced if compared to the case when the interaction with the host immune system does not play a central role in the evolutive dynamics. While many imbalance metrics have been introduced, reliable methods to discriminate in a quantitative way different level of imbalance are still lacking. In our work, we reconstruct and analyze the phylogenetic trees of six RNA viruses, with a special emphasis on the human Influenza A virus, due to its relevance for vaccine preparation as well as for the theoretical challenges it poses due to its peculiar evolutionary dynamics. We focus in particular on topological properties. We point out the limitation featured by standard imbalance metrics, and we introduce a new methodology with which we assign the correct imbalance level of the phylogenetic trees, in agreement with the phylodynamics of the viruses. Our thorough quantitative analysis allows for a deeper understanding of the evolutionary dynamics of the considered RNA viruses, which is crucial in order to provide a valuable framework for a quantitative assessment of theoretical predictions.
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Affiliation(s)
- Simone Pompei
- Complex Systems Lagrange Lab, Institute for Scientific Interchange-ISI, Torino, Italy.
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A quantitative quasispecies theory-based model of virus escape mutation under immune selection. Proc Natl Acad Sci U S A 2012; 109:12980-5. [PMID: 22826258 DOI: 10.1073/pnas.1117201109] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Viral infections involve a complex interplay of the immune response and escape mutation of the virus quasispecies inside a single host. Although fundamental aspects of such a balance of mutation and selection pressure have been established by the quasispecies theory decades ago, its implications have largely remained qualitative. Here, we present a quantitative approach to model the virus evolution under cytotoxic T-lymphocyte immune response. The virus quasispecies dynamics are explicitly represented by mutations in the combined sequence space of a set of epitopes within the viral genome. We stochastically simulated the growth of a viral population originating from a single wild-type founder virus and its recognition and clearance by the immune response, as well as the expansion of its genetic diversity. Applied to the immune escape of a simian immunodeficiency virus epitope, model predictions were quantitatively comparable to the experimental data. Within the model parameter space, we found two qualitatively different regimes of infectious disease pathogenesis, each representing alternative fates of the immune response: It can clear the infection in finite time or eventually be overwhelmed by viral growth and escape mutation. The latter regime exhibits the characteristic disease progression pattern of human immunodeficiency virus, while the former is bounded by maximum mutation rates that can be suppressed by the immune response. Our results demonstrate that, by explicitly representing epitope mutations and thus providing a genotype-phenotype map, the quasispecies theory can form the basis of a detailed sequence-specific model of real-world viral pathogens evolving under immune selection.
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Sanz-Ramos M, Rodríguez-Calvo T, Sevilla N. Mutagenesis-mediated decrease of pathogenicity as a feature of the mutant spectrum of a viral population. PLoS One 2012; 7:e39941. [PMID: 22761933 PMCID: PMC3386257 DOI: 10.1371/journal.pone.0039941] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Accepted: 05/29/2012] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND RNA virus populations are heterogeneous ensembles of closely related genomes termed quasispecies. This highly complex distribution of variants confers important properties to RNA viruses and influences their pathogenic behavior. It has been hypothesized that increased mutagenesis of viral populations, by treatment with mutagenic agents, can induce alterations in the pathogenic potential of a virus population. In this work we investigate whether mutagenized foot-and-mouth disease virus (FMDV) populations display changes in their virulence in mice. METHODOLOGY AND PRINCIPAL FINDINGS FMDV C-S8c1 was passaged in BHK cells in the presence of the mutagenic agent ribavirin. Decline in viral titer and viral RNA progeny was observed in the first passage, fluctuating around a constant value thereafter. Hence, the specific infectivity remained stable during the passages. The viral population harvested from passage 9 (P9 R) showed decreased virulence in mice, with a lethal dose 50 (LD(50)) >10(4) PFU, as compared with LD(50) of 50 PFU of the parental population FMDV C-S8c1. This decrease in virulence was associated to a 20-fold increase in the mutation frequency of the P9 R population with respect to C-S8c1. Interestingly, individual biological clones isolated from the attenuated population P9 R were as virulent as the parental virus C-S8c1. Furthermore, a mixed population of C-S8c1 and P9 R was inoculated into mice and showed decreased virulence as compared to C-S8c1, suggesting that population P9 R is able to suppress the virulent phenotype of C-S8c1. CONCLUSION Ribavirin-mediated mutagenesis of an FMDV population resulted in attenuation in vivo, albeit a large proportion of its biological clones displayed a highly virulent phenotype. These results, together with the suppression of C-S8c1 by mutagenized P9 R population, document a suppressive effect of mutagenized viral quasispecies in vivo, and suggest novel approaches to the treatment and prevention of viral diseases.
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Affiliation(s)
- Marta Sanz-Ramos
- Centro de Investigación en Sanidad Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (CISA-INIA), Valdeolmos, Madrid, Spain
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, Madrid, Spain
| | - Teresa Rodríguez-Calvo
- Centro de Investigación en Sanidad Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (CISA-INIA), Valdeolmos, Madrid, Spain
| | - Noemí Sevilla
- Centro de Investigación en Sanidad Animal, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (CISA-INIA), Valdeolmos, Madrid, Spain
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Abstract
Evolution of RNA viruses occurs through disequilibria of collections of closely related mutant spectra or mutant clouds termed viral quasispecies. Here we review the origin of the quasispecies concept and some biological implications of quasispecies dynamics. Two main aspects are addressed: (i) mutant clouds as reservoirs of phenotypic variants for virus adaptability and (ii) the internal interactions that are established within mutant spectra that render a virus ensemble the unit of selection. The understanding of viruses as quasispecies has led to new antiviral designs, such as lethal mutagenesis, whose aim is to drive viruses toward low fitness values with limited chances of fitness recovery. The impact of quasispecies for three salient human pathogens, human immunodeficiency virus and the hepatitis B and C viruses, is reviewed, with emphasis on antiviral treatment strategies. Finally, extensions of quasispecies to nonviral systems are briefly mentioned to emphasize the broad applicability of quasispecies theory.
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Affiliation(s)
- Esteban Domingo
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), C/ Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
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Ciota AT, Ehrbar DJ, Van Slyke GA, Willsey GG, Kramer LD. Cooperative interactions in the West Nile virus mutant swarm. BMC Evol Biol 2012; 12:58. [PMID: 22541042 PMCID: PMC3358237 DOI: 10.1186/1471-2148-12-58] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Accepted: 04/27/2012] [Indexed: 03/11/2023] Open
Abstract
Background RNA viruses including arthropod-borne viruses (arboviruses) exist as highly genetically diverse mutant swarms within individual hosts. A more complete understanding of the phenotypic correlates of these diverse swarms is needed in order to equate RNA swarm breadth and composition to specific adaptive and evolutionary outcomes. Results Here, we determined clonal fitness landscapes of mosquito cell-adapted West Nile virus (WNV) and assessed how altering the capacity for interactions among variants affects mutant swarm dynamics and swarm fitness. Our results demonstrate that although there is significant mutational robustness in the WNV swarm, genetic diversity also corresponds to substantial phenotypic diversity in terms of relative fitness in vitro. In addition, our data demonstrate that increasing levels of co-infection can lead to widespread strain complementation, which acts to maintain high levels of phenotypic and genetic diversity and potentially slow selection for individual variants. Lastly, we show that cooperative interactions may lead to swarm fitness levels which exceed the relative fitness levels of any individual genotype. Conclusions These studies demonstrate the profound effects variant interactions can have on arbovirus evolution and adaptation, and provide a baseline by which to study the impact of this phenomenon in natural systems.
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Affiliation(s)
- Alexander T Ciota
- New York State Department of Health, Wadsworth Center, Slingerlands, NY, USA
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Dortmans JCFM, Koch G, Rottier PJM, Peeters BPH. Virulence of Newcastle disease virus: what is known so far? Vet Res 2011; 42:122. [PMID: 22195547 PMCID: PMC3269386 DOI: 10.1186/1297-9716-42-122] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/23/2011] [Indexed: 12/22/2022] Open
Abstract
In the last decade many studies have been performed on the virulence of Newcastle disease virus (NDV). This is mainly due to the development of reverse genetics systems which made it possible to genetically modify NDV and to investigate the contribution of individual genes and genome regions to its virulence. However, the available information is scattered and a comprehensive overview of the factors and conditions determining NDV virulence is lacking. This review summarises, compares and discusses the available literature and shows that virulence of NDV is a complex trait determined by multiple genetic factors.
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Affiliation(s)
- Jos C F M Dortmans
- Central Veterinary Institute of Wageningen UR, PO Box 65, 8200 AB Lelystad, The Netherlands.
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Lancaster KZ, Pfeiffer JK. Mechanisms controlling virulence thresholds of mixed viral populations. J Virol 2011; 85:9778-88. [PMID: 21795346 PMCID: PMC3196390 DOI: 10.1128/jvi.00355-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 07/16/2011] [Indexed: 02/05/2023] Open
Abstract
The propensity of RNA viruses to revert attenuating mutations contributes to disease and complicates vaccine development. Despite the presence of virulent revertant viruses in some live-attenuated vaccines, disease from vaccination is rare. This suggests that in mixed viral populations, attenuated viruses may limit the pathogenesis of virulent viruses, thus establishing a virulence threshold. Here we examined virulence thresholds using mixtures of virulent and attenuated viruses in a transgenic mouse model of poliovirus infection. We determined that a 1,000-fold excess of the attenuated Sabin strain of poliovirus was protective against disease induced by the virulent Mahoney strain. Protection was induced locally, and inactivated virus conferred protection. Treatment with a poliovirus receptor-blocking antibody phenocopied the protective effect of inactivated viruses in vitro and in vivo, suggesting that one mechanism controlling virulence thresholds may be competition for a viral receptor. Additionally, the type I interferon response reduces poliovirus pathogenesis; therefore, we examined virulence thresholds in mice lacking the alpha/beta interferon receptor. We found that the attenuated virus was virulent in immunodeficient mice due to the enhanced replication and reversion of attenuating mutations. Therefore, while the type I interferon response limits the virulence of the attenuated strain by reducing replication, protection from disease conferred by the attenuated strain in immunocompetent mice can occur independently of replication. Our results identified mechanisms controlling the virulence of mixed viral populations and indicate that live-attenuated vaccines containing virulent virus may be safe, as long as virulent viruses are present at levels below a critical threshold.
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Affiliation(s)
| | - Julie K. Pfeiffer
- Corresponding author. Mailing address: Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9048. Phone: (214) 633-1377. Fax: (214) 648-5905. E-mail:
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Ciota AT, Kramer LD. Insights into arbovirus evolution and adaptation from experimental studies. Viruses 2010; 2:2594-617. [PMID: 21994633 PMCID: PMC3185588 DOI: 10.3390/v2122594] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 11/18/2010] [Accepted: 11/22/2010] [Indexed: 12/22/2022] Open
Abstract
Arthropod-borne viruses (arboviruses) are maintained in nature by cycling between vertebrate hosts and haematophagous invertebrate vectors. These viruses are responsible for causing a significant public health burden throughout the world, with over 100 species having the capacity to cause human disease. Arbovirus outbreaks in previously naïve environments demonstrate the potential of these pathogens for expansion and emergence, possibly exacerbated more recently by changing climates. These recent outbreaks, together with the continued devastation caused by endemic viruses, such as Dengue virus which persists in many areas, demonstrate the need to better understand the selective pressures that shape arbovirus evolution. Specifically, a comprehensive understanding of host-virus interactions and how they shape both host-specific and virus-specific evolutionary pressures is needed to fully evaluate the factors that govern the potential for host shifts and geographic expansions. One approach to advance our understanding of the factors influencing arbovirus evolution in nature is the use of experimental studies in the laboratory. Here, we review the contributions that laboratory passage and experimental infection studies have made to the field of arbovirus adaptation and evolution, and how these studies contribute to the overall field of arbovirus evolution. In particular, this review focuses on the areas of evolutionary constraints and mutant swarm dynamics; how experimental results compare to theoretical predictions; the importance of arbovirus ecology in shaping viral swarms; and how current knowledge should guide future questions relevant to understanding arbovirus evolution.
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Affiliation(s)
- Alexander T. Ciota
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA; E-Mail:
- University at Albany, State University of New York, Albany, NY 12222, USA
| | - Laura D. Kramer
- The Arbovirus Laboratories, Wadsworth Center, New York State Department of Health, Slingerlands, NY 12159, USA; E-Mail:
- University at Albany, State University of New York, Albany, NY 12222, USA
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-518-485-6632; Fax: 1-518-485-6669
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Perales C, Lorenzo-Redondo R, López-Galíndez C, Martínez MA, Domingo E. Mutant spectra in virus behavior. Future Virol 2010. [DOI: 10.2217/fvl.10.61] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RNA viruses replicate as complex mutant spectra, also termed ‘mutant clouds’, known as viral quasispecies. While this is a widely observed viral population structure, it is less known that a number of biologically relevant features of this important group of viral pathogens depend on (or are strongly influenced by) the complexity and composition of mutant spectra. Among them, fitness increase or decrease depending on intrapopulation complementation or interference, selection triggered by memory genomes, pathogenic potential of viruses, disease evolution and the response to antiviral treatments. Quasispecies represent the recognition of complex behavior in viruses, and it is an oversimplification to equate such a population structure with the classic polymorphism of population biology. Darwinian principles acting on genome collectivities that replicate with high error rates provide a unique population structure prone to flexible and largely unpredictable behavior.
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Affiliation(s)
- Celia Perales
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), C/ Nicolás Cabrera, 1 Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain
| | - Ramón Lorenzo-Redondo
- Centro Nacional de Microbiología (CNM), Instituto de Salud Carlos III, Majadahonda, Madrid 28220, Spain
| | - Cecilio López-Galíndez
- Centro Nacional de Microbiología (CNM), Instituto de Salud Carlos III, Majadahonda, Madrid 28220, Spain
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Pathogenicity evaluation of different Newcastle disease virus chimeras in 4-week-old chickens. Trop Anim Health Prod 2010; 42:1785-95. [PMID: 20614237 DOI: 10.1007/s11250-010-9638-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2010] [Indexed: 10/19/2022]
Abstract
The aim of this study was to evaluate the disease-inducing ability of four chimeric Newcastle disease viruses (NDV) by clinicopathological assessment. The infectious clones were previously generated by insertion of hemagglutinin-neuraminidase (HN) and/or fusion (F) genes from virulent strains (Turkey North Dakota and California 02) into a mesogenic strain (Anhinga) backbone. Groups of 4-week-old chickens were inoculated via eye drop instillation, clinical signs were monitored daily, and necropsies with collection of tissues were performed at 2, 5, 10, and 14 days post infection. Tissue sections were evaluated for histopathology and immunohistochemistry for NDV nucleoprotein. All viruses replicated successfully in the natural host, although viral recovery, seroconversion, and extent of immunohistochemical staining were greatest from birds infected with those viruses containing both F and HN genes from the same virulent virus. There was minimal to no increase in clinicopathologic disease due to infection with the chimeras compared to the recombinant backbone. However, all birds developed histological evidence of encephalitis. The results suggest that the inherent virulence of Turkey North Dakota and California 2002 strains is due to more than the simple presence of their F and HN genes.
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Genomic evolution of vesicular stomatitis virus strains with differences in adaptability. J Virol 2010; 84:4960-8. [PMID: 20181701 DOI: 10.1128/jvi.00710-09] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Virus strains with a history of repeated genetic bottlenecks frequently show a diminished ability to adapt compared to strains that do not have such a history. These differences in adaptability suggest differences in either the rate at which beneficial mutations are produced, the effects of beneficial mutations, or both. We tested these possibilities by subjecting four populations (two controls and two mutants with lower adaptabilities) to multiple replicas of a regimen of positive selection and then determining the fitnesses of the progeny through time and the changes in the consensus, full-length sequences of 56 genomes. We observed that at a given number of passages, the overall fitness gains observed for control populations were larger than fitness gains in mutant populations. However, these changes did not correlate with differences in the numbers of mutations accumulated in the two types of genomes. This result is consistent with beneficial mutations having a lower beneficial effect on mutant strains. Despite the overall fitness differences, some replicas of one mutant strain at passage 50 showed fitness increases similar to those observed for the wild type. We hypothesized that these evolved, high-fitness mutants may have a lower robustness than evolved, high-fitness controls. Robustness is the ability of a virus to avoid phenotypic changes in the face of mutation. We confirmed our hypothesis in mutation-accumulation experiments that showed a normalized fitness loss that was significantly larger in mutant bottlenecked populations than in control populations.
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Generation and biological assessment of recombinant avian metapneumovirus subgroup C (aMPV-C) viruses containing different length of the G gene. Virus Res 2010; 147:182-8. [DOI: 10.1016/j.virusres.2009.10.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 10/27/2009] [Accepted: 10/29/2009] [Indexed: 11/19/2022]
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Pfeiffer JK. Innate host barriers to viral trafficking and population diversity: lessons learned from poliovirus. Adv Virus Res 2010; 77:85-118. [PMID: 20951871 PMCID: PMC3234684 DOI: 10.1016/b978-0-12-385034-8.00004-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Poliovirus is an error-prone enteric virus spread by the fecal-oral route and rarely invades the central nervous system (CNS). However, in the rare instances when poliovirus invades the CNS, the resulting damage to motor neurons is striking and often permanent. In the prevaccine era, it is likely that most individuals within an epidemic community were infected; however, only 0.5% of infected individuals developed paralytic poliomyelitis. Paralytic poliomyelitis terrified the public and initiated a huge research effort, which was rewarded with two outstanding vaccines. During research to develop the vaccines, many questions were asked: Why did certain people develop paralysis? How does the virus move from the gut to the CNS? What limits viral trafficking to the CNS in the vast majority of infected individuals? Despite over 100 years of poliovirus research, many of these questions remain unanswered. The goal of this chapter is to review our knowledge of how poliovirus moves within and between hosts, how host barriers limit viral movement, how viral population dynamics impact viral fitness and virulence, and to offer hypotheses to explain the rare incidence of paralytic poliovirus disease.
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Affiliation(s)
- Julie K Pfeiffer
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Vasilakis N, Deardorff ER, Kenney JL, Rossi SL, Hanley KA, Weaver SC. Mosquitoes put the brake on arbovirus evolution: experimental evolution reveals slower mutation accumulation in mosquito than vertebrate cells. PLoS Pathog 2009; 5:e1000467. [PMID: 19503824 PMCID: PMC2685980 DOI: 10.1371/journal.ppat.1000467] [Citation(s) in RCA: 126] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 05/07/2009] [Indexed: 01/24/2023] Open
Abstract
Like other arthropod-borne viruses (arboviruses), mosquito-borne dengue virus (DENV) is maintained in an alternating cycle of replication in arthropod and vertebrate hosts. The trade-off hypothesis suggests that this alternation constrains DENV evolution because a fitness increase in one host usually diminishes fitness in the other. Moreover, the hypothesis predicts that releasing DENV from host alternation should facilitate adaptation. To test this prediction, DENV was serially passaged in either a single human cell line (Huh-7), a single mosquito cell line (C6/36), or in alternating passages between Huh-7 and C6/36 cells. After 10 passages, consensus mutations were identified and fitness was assayed by evaluating replication kinetics in both cell types as well as in a novel cell type (Vero) that was not utilized in any of the passage series. Viruses allowed to specialize in single host cell types exhibited fitness gains in the cell type in which they were passaged, but fitness losses in the bypassed cell type, and most alternating passages, exhibited fitness gains in both cell types. Interestingly, fitness gains were observed in the alternately passaged, cloned viruses, an observation that may be attributed to the acquisition of both host cell-specific and amphi-cell-specific adaptations or to recovery from the fitness losses due to the genetic bottleneck of biological cloning. Amino acid changes common to both passage series suggested convergent evolution to replication in cell culture via positive selection. However, intriguingly, mutations accumulated more rapidly in viruses passed in Huh-7 cells than in those passed in C6/36 cells or in alternation. These results support the hypothesis that releasing DENV from host alternation facilitates adaptation, but there is limited support for the hypothesis that such alternation necessitates a fitness trade-off. Moreover, these findings suggest that patterns of genetic evolution may differ between viruses replicating in mammalian and mosquito cells.
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Affiliation(s)
- Nikos Vasilakis
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Eleanor R. Deardorff
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Joan L. Kenney
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Shannan L. Rossi
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Kathryn A. Hanley
- Department of Biology, New Mexico State University, Las Cruces, New Mexico, United States of America
| | - Scott C. Weaver
- Center for Biodefense and Emerging Infectious Diseases and Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Arenavirus genetic diversity and its biological implications. INFECTION GENETICS AND EVOLUTION 2009; 9:417-29. [PMID: 19460307 PMCID: PMC7106275 DOI: 10.1016/j.meegid.2009.03.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2009] [Revised: 03/13/2009] [Accepted: 03/13/2009] [Indexed: 12/15/2022]
Abstract
The Arenaviridae family currently comprises 22 viral species, each of them associated with a rodent species. This viral family is important both as tractable experimental model systems to study acute and persistent infections and as clinically important human pathogens. Arenaviruses are enveloped viruses with a bi-segmented negative-strand RNA genome. The interaction with the cellular receptor and subsequent entry into the host cell differs between Old World and New World arenavirus that use α-dystoglycan or human transferring receptor 1, respectively, as main receptors. The recent development of reverse genetic systems for several arenaviruses has facilitated progress in understanding the molecular biology and cell biology of this viral family, as well as opening new approaches for the development of novel strategies to combat human pathogenic arenaviruses. On the other hand, increased availability of genetic data has allowed more detailed studies on the phylogeny and evolution of arenaviruses. As with other riboviruses, arenaviruses exist as viral quasispecies, which allow virus adaptation to rapidly changing environments. The large number of different arenavirus host reservoirs and great genetic diversity among virus species provide the bases for the emergence of new arenaviruses potentially pathogenic for humans.
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43
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Troyer RM, Garver KA, Ranson JC, Wargo AR, Kurath G. In vivo virus growth competition assays demonstrate equal fitness of fish rhabdovirus strains that co-circulate in aquaculture. Virus Res 2008; 137:179-88. [PMID: 18703096 DOI: 10.1016/j.virusres.2008.07.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2008] [Revised: 07/03/2008] [Accepted: 07/04/2008] [Indexed: 10/21/2022]
Abstract
A novel virus growth competition assay for determining relative fitness of RNA virus variants in vivo has been developed using the fish rhabdovirus, Infectious hematopoietic necrosis virus (IHNV), in juvenile rainbow trout (Oncorhynchus mykiss). We have conducted assays with IHNV isolates designated B, C, and D, representing the three most common genetic subtypes that co-circulate in Idaho trout farm aquaculture. In each assay, groups of 30 fish were immersed in a 1:1 mixture of two genotypes of IHNV, and then held in individual beakers for a 72h period of in vivo competitive virus replication. Progeny virus populations in each fish were analyzed for the presence and proportion of each viral genotype. In two independent assays of the B:C isolate pair, and two assays of the B:D pair, all fish were co-infected and there was a high level of fish-to-fish variation in the ratio of the two competing genotypes. However, in each assay the average ratio in the 30-fish group was not significantly different from the input ratio of 1:1, indicating equal or nearly equal viral fitness on a host population basis, under the conditions tested.
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Affiliation(s)
- Ryan M Troyer
- U.S. Geological Survey, Western Fisheries Research Center, 6505 NE 65th Street, Seattle, WA 98115, USA
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44
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Presloid JB, Ebendick-Corpus BE, Zárate S, Novella IS. Antagonistic pleiotropy involving promoter sequences in a virus. J Mol Biol 2008; 382:342-52. [PMID: 18644381 DOI: 10.1016/j.jmb.2008.06.080] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 06/24/2008] [Accepted: 06/27/2008] [Indexed: 11/30/2022]
Abstract
Selection of specialist genotypes, that is, populations with limited niche width, promotes the maintenance of diversity. Specialization to a particular environment may have a cost in other environments, including fitness tradeoffs. When the tradeoffs are the result of mutations that have a beneficial effect in the selective environment but a deleterious effect in other environments, we have antagonistic pleiotropy. Alternatively, tradeoffs can result from the fixation of mutations that are neutral in the selective environment but have a negative effect in other environments, and thus the tradeoff is due to mutation accumulation. We tested the mechanisms underlying the fitness tradeoffs observed during adaptation to persistent infection of vesicular stomatitis virus in insect cells by sequencing the full-length genomes of 12 strains with a history of replication in a single niche (acute mammalian infection or persistent insect infection) or in temporally heterogeneous niches and correlated genetic and fitness changes. Ecological theory predicts a correlation between the selective environment and the niche width of the evolved populations, such that adaptation to single niches should lead to the selection of specialists and niche cycling should result in the selection of generalists. Contrary to this expectation, adaptation to one of the single niches resulted in a generalist and adaptation to a heterogeneous environment led to the selection of a specialist. Only one-third of the mutations that accumulated during persistent infection had a fitness cost that could be explained in all cases by antagonistic pleiotropy. Mutations involved in fitness tradeoffs included changes in regulatory sequences, particularly at the 3' termini of the genomes, which contain the single promoter that controls viral transcription and replication.
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Affiliation(s)
- John B Presloid
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine, 3055 Arlington Avenue, Toledo, OH 43614, USA
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45
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Dutta RN, Rouzine IM, Smith SD, Wilke CO, Novella IS. Rapid adaptive amplification of preexisting variation in an RNA virus. J Virol 2008; 82:4354-62. [PMID: 18287227 PMCID: PMC2293023 DOI: 10.1128/jvi.02446-07] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Accepted: 02/13/2008] [Indexed: 11/20/2022] Open
Abstract
The amount and nature of preexisting variation in a population of RNA viruses is an important determinant of the virus's ability to adapt rapidly to a changed environment. However, direct quantification of this preexisting variation may be cumbersome, because potentially beneficial alleles are typically rare, and isolation of a large number of subclones is required. Here, we propose a simpler method. We infer the initial population structure of vesicular stomatitis virus (VSV) by fitting a mathematical model of asexual evolution to an extensive set of measurements of VSV fitness dynamics under various conditions, including new and previously published data. The inferred variation of fitness in the initial population agrees very well with the results of direct experiments with subclone fitness quantification. From the same procedure, we also estimate the mean fitness effect of beneficial mutations (selection coefficient s), the percentage of sites in the genome that are under moderate positive or negative selection, and the percentage of sites where beneficial mutations may potentially occur. For VSV strain MARM U evolving in BHK-21 cells, the three parameters have values of 0.39, 9%, and 0.06%, respectively. The method can be generalized and applied easily to other rapidly evolving microbes, including both asexual microorganisms and those with recombination.
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Affiliation(s)
- Ranendra N Dutta
- Department of Medical Microbiology and Immunology, University of Toledo Health Science Campus, Toledo, OH 43614, USA
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46
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Aguirre J, Manrubia SC. Effects of spatial competition on the diversity of a quasispecies. PHYSICAL REVIEW LETTERS 2008; 100:038106. [PMID: 18233044 DOI: 10.1103/physrevlett.100.038106] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Indexed: 05/25/2023]
Abstract
The diversity harbored by populations of RNA viruses results from high mutation rates, as well as from the characteristics of the environment where they evolve. By means of a simple model for structured quasispecies, we quantify how competition for space among phenotypic types shapes their distribution at the mutation-selection equilibrium. We introduce a general framework to treat this problem and relate mutation rate and competition strength to the quasispecies composition. For diffusion limited competition, diversity typically increases and the asymptotic growth rate of the population diminishes as diffusion decreases. Limited mobility confers a relative advantage to worse competitors. The stationary state is characterized by an over-production of viral particles. Empirical data allow an estimation of mutation rates compatible with the diversity observed in viral populations infecting cellular monolayers.
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Affiliation(s)
- Jacobo Aguirre
- Centro de Astrobiología, CSIC-INTA. Ctra. de Ajalvir km. 4 28850 Torrejón de Ardoz, Madrid, Spain
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47
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Domingo E, Escarmís C, Menéndez-Arias L, Perales C, Herrera M, Novella IS, Holland JJ. Viral Quasispecies: Dynamics, Interactions, and Pathogenesis *. ORIGIN AND EVOLUTION OF VIRUSES 2008. [PMCID: PMC7149507 DOI: 10.1016/b978-0-12-374153-0.00004-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Quasispecies theory is providing a solid, evolving conceptual framework for insights into virus population dynamics, adaptive potential, and response to lethal mutagenesis. The complexity of mutant spectra can influence disease progression and viral pathogenesis, as demonstrated using virus variants selected for increased replicative fidelity. Complementation and interference exerted among components of a viral quasispecies can either reinforce or limit the replicative capacity and disease potential of the ensemble. In particular, a progressive enrichment of a replicating mutant spectrum with interfering mutant genomes prompted by enhanced mutagenesis may be a key event in the sharp transition of virus populations into error catastrophe that leads to virus extinction. Fitness variations are influenced by the passage regimes to which viral populations are subjected, notably average fitness decreases upon repeated bottleneck events and fitness gains upon competitive optimization of large viral populations. Evolving viral quasispecies respond to selective constraints by replication of subpopulations of variant genomes that display higher fitness than the parental population in the presence of the selective constraint. This has been profusely documented with fitness effects of mutations associated with resistance of pathogenic viruses to antiviral agents. In particular, selection of HIV-1 mutants resistant to one or multiple antiretroviral inhibitors, and the compensatory effect of mutations in the same genome, offers a compendium of the molecular intricacies that a virus can exploit for its survival. This chapter reviews the basic principles of quasispecies dynamics as they can serve to explain the behavior of viruses.
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48
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Estevez C, King D, Seal B, Yu Q. Evaluation of Newcastle disease virus chimeras expressing the Hemagglutinin-Neuraminidase protein of velogenic strains in the context of a mesogenic recombinant virus backbone. Virus Res 2007; 129:182-90. [PMID: 17719672 DOI: 10.1016/j.virusres.2007.07.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 07/12/2007] [Accepted: 07/14/2007] [Indexed: 10/22/2022]
Abstract
A major factor in the pathogenicity of Newcastle disease virus (NDV) is the amino acid sequence of the fusion protein cleavage site, but the role of other viral genes that contribute to virulence and different clinical forms of the disease remain undefined. To assess the role of other NDV genes in virus pathogenicity, a reverse genetics system was developed using the mesogenic NDV Anhinga strain to provide a backbone for generating gene mutations or gene exchanges in attempts to enhance or attenuate the virulence of that virus. Chimeras created by exchange of the Anhinga Hemagglutinin-Neuraminidase (HN) gene with HN genes of neurotropic and viscerotropic velogenic viruses produced no significant change in virus pathogenicity as assessed by conducting the mean death time and intracerebral pathogenicity index assays and by inoculation of susceptible day-old SPF chickens. Inclusion in the recombinant construct of homotypic F genes, obtained from the parental viruses, also failed to enhance the pathotype of the recombinant viruses to a velogenic pathotype. A HN gene exchange alone within the context of the NDV Anhinga backbone failed to increase virus virulence from mesogenic to velogenic pathotype and suggests a multigenic role for NDV pathogenicity.
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Affiliation(s)
- Carlos Estevez
- Southeast Poultry Research Laboratory, Agricultural Research Service, United States Department of Agriculture, 934 College Station Road, Athens, GA 30605, USA
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49
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Novella IS, Ebendick-Corpus BE, Zárate S, Miller EL. Emergence of mammalian cell-adapted vesicular stomatitis virus from persistent infections of insect vector cells. J Virol 2007; 81:6664-8. [PMID: 17428845 PMCID: PMC1900099 DOI: 10.1128/jvi.02365-06] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Accepted: 04/02/2007] [Indexed: 11/20/2022] Open
Abstract
Arboviruses (arthropod-borne viruses) represent quintessential generalists, with the ability to infect and perform well in multiple hosts. However, antagonistic pleiotropy imposed a cost during the adaptation to persistent replication of vesicular stomatitis virus in sand fly cells and resulted in strains that initially replicated poorly in hamster cells, even when the virus was allowed to replicate periodically in the latter. Once a debilitated strain started replicating continuously in mammalian cells, fitness increased significantly. Fitness recovery did not entail back mutations or compensatory mutations, but instead, we observed the replacement of persistence-adapted genomes by mammalian cell-adapted strains with a full set of new, unrelated sequence changes. These mammalian cell-adapted genomes were present at low frequencies in the populations with a history of persistence for up to a year and quickly became dominant during mammalian infection, but coexistence was not stable in the long term. Periodic acute replication in mammalian cells likely contributed to extending the survival of minority genomes, but these genomes were also found in strictly persistent populations.
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Affiliation(s)
- Isabel S Novella
- Department of Medical Microbiology and Immunology, Medical University of Ohio, 3055 Arlington Ave., Toledo, OH 43614, USA.
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50
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de la Iglesia F, Elena SF. Fitness declines in Tobacco etch virus upon serial bottleneck transfers. J Virol 2007; 81:4941-7. [PMID: 17344305 PMCID: PMC1900225 DOI: 10.1128/jvi.02528-06] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Accepted: 02/23/2007] [Indexed: 01/10/2023] Open
Abstract
It has been well established that populations of RNA viruses transmitted throughout serial bottlenecks suffer from significant fitness declines as a consequence of the accumulation of deleterious mutations by the onset of Muller's ratchet. Bottlenecks are unavoidably linked to different steps of the infectious cycle of most plant RNA viruses, such as vector-mediated transmissions and systemic colonization of new leaves. Here we report evidence for fitness declines by the accumulation of deleterious mutations in the potyvirus Tobacco etch virus (TEV). TEV was inoculated into the nonsystemic host Chenopodium quinoa, and local lesions were isolated and used to initiate 20 independent mutation accumulation lineages. Weekly, a random lesion from each lineage was isolated and used to inoculate the next set of plants. At each transfer, the Malthusian growth rate was estimated. After 11 consecutive transfers, all lineages suffered significant fitness losses, and one even became extinct. The average rate of fitness decline was 5% per day. The average pattern of fitness decline was consistent with antagonistic epistasis between deleterious mutations, as postulated for antiredundant genomes. Temporal fitness fluctuations were not explained by random noise but reflected more complex underlying processes related to emergence and self-organization phenomena.
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Affiliation(s)
- Francisca de la Iglesia
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022 València, Spain
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