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Pauciullo S, Zulian V, La Frazia S, Paci P, Garbuglia AR. Spillover: Mechanisms, Genetic Barriers, and the Role of Reservoirs in Emerging Pathogens. Microorganisms 2024; 12:2191. [PMID: 39597581 PMCID: PMC11596118 DOI: 10.3390/microorganisms12112191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2024] [Revised: 10/16/2024] [Accepted: 10/28/2024] [Indexed: 11/29/2024] Open
Abstract
Viral spillover represents the transmission of pathogen viruses from one species to another that can give rise to an outbreak. It is a critical concept that has gained increasing attention, particularly after the SARS-CoV-2 pandemic. However, the term is often used inaccurately to describe events that do not meet the true definition of spillover. This review aims to clarify the proper use of the term and provides a detailed analysis of the mechanisms driving zoonotic spillover, with a focus on the genetic and environmental factors that enable viruses to adapt to new hosts. Key topics include viral genetic variability in reservoir species, biological barriers to cross-species transmission, and the factors that influence viral adaptation and spread in novel hosts. The review also examines the role of evolutionary processes such as mutation and epistasis, alongside ecological conditions that facilitate the emergence of new pathogens. Ultimately, it underscores the need for more accurate predictive models and improved surveillance to better anticipate and mitigate future spillover events.
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Affiliation(s)
- Silvia Pauciullo
- Laboratory of Virology, National Institute for Infectious Diseases “Lazzaro Spallanzani” (IRCCS), 00149 Rome, Italy; (S.P.); (V.Z.)
| | - Verdiana Zulian
- Laboratory of Virology, National Institute for Infectious Diseases “Lazzaro Spallanzani” (IRCCS), 00149 Rome, Italy; (S.P.); (V.Z.)
| | - Simone La Frazia
- Department of Biology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy;
| | - Paola Paci
- Department of Computer, Control, and Management Engineering “A. Ruberti” (DIAG), Sapienza University of Rome, 00185 Rome, Italy;
| | - Anna Rosa Garbuglia
- Laboratory of Virology, National Institute for Infectious Diseases “Lazzaro Spallanzani” (IRCCS), 00149 Rome, Italy; (S.P.); (V.Z.)
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2
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Illingworth CJR, Guerra-Assuncao JA, Gregg S, Charles O, Pang J, Roy S, Abdelnabi R, Neyts J, Breuer J. Genetic consequences of effective and suboptimal dosing with mutagenic drugs in a hamster model of SARS-CoV-2 infection. Virus Evol 2024; 10:veae001. [PMID: 38486802 PMCID: PMC10939363 DOI: 10.1093/ve/veae001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 11/23/2023] [Accepted: 01/03/2024] [Indexed: 03/17/2024] Open
Abstract
Mutagenic antiviral drugs have shown promise against multiple viruses, but concerns have been raised about whether their use might promote the emergence of new and harmful viral variants. Recently, genetic signatures associated with molnupiravir use have been identified in the global SARS-COV-2 population. Here, we examine the consequences of using favipiravir and molnupiravir to treat SARS-CoV-2 infection in a hamster model, comparing viral genome sequence data collected from (1) untreated hamsters, and (2) from hamsters receiving effective and suboptimal doses of treatment. We identify a broadly linear relationship between drug dose and the extent of variation in treated viral populations, with a high proportion of this variation being composed of variants at frequencies of less than 1 per cent, below typical thresholds for variant calling. Treatment with an effective dose of antiviral drug was associated with a gain of between 7 and 10 variants per viral genome relative to drug-free controls: even after a short period of treatment a population founded by a transmitted virus could contain multiple sequence differences to that of the original host. Treatment with a suboptimal dose of drug showed intermediate gains of variants. No dose-dependent signal was identified in the numbers of single-nucleotide variants reaching frequencies in excess of 5 per cent. We did not find evidence to support the emergence of drug resistance or of novel immune phenotypes. Our study suggests that where onward transmission occurs, a short period of treatment with mutagenic drugs may be sufficient to generate a significant increase in the number of viral variants transmitted.
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Affiliation(s)
| | - Jose A Guerra-Assuncao
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
- Infection, Immunity and Inflammation Research and Teaching Department, University College London, Gower Street, London WC1E 6BT, UK
| | - Samuel Gregg
- Infection, Immunity and Inflammation Research and Teaching Department, University College London, Gower Street, London WC1E 6BT, UK
| | - Oscar Charles
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
- Infection, Immunity and Inflammation Research and Teaching Department, University College London, Gower Street, London WC1E 6BT, UK
| | - Juanita Pang
- Infection, Immunity and Inflammation Research and Teaching Department, University College London, Gower Street, London WC1E 6BT, UK
| | - Sunando Roy
- Infection, Immunity and Inflammation Research and Teaching Department, University College London, Gower Street, London WC1E 6BT, UK
| | - Rana Abdelnabi
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Leuven B-3000, Belgium
- The VirusBank Platform, Gaston Geenslaan, Leuven B-3000, Belgium
| | - Johan Neyts
- KU Leuven Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Leuven B-3000, Belgium
- The VirusBank Platform, Gaston Geenslaan, Leuven B-3000, Belgium
| | - Judith Breuer
- Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London WC1N 3JH, UK
- Infection, Immunity and Inflammation Research and Teaching Department, University College London, Gower Street, London WC1E 6BT, UK
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3
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Catching A, Te Yeh M, Bianco S, Capponi S, Andino R. A tradeoff between enterovirus A71 particle stability and cell entry. Nat Commun 2023; 14:7450. [PMID: 37978288 PMCID: PMC10656440 DOI: 10.1038/s41467-023-43029-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/26/2023] [Indexed: 11/19/2023] Open
Abstract
A central role of viral capsids is to protect the viral genome from the harsh extracellular environment while facilitating initiation of infection when the virus encounters a target cell. Viruses are thought to have evolved an optimal equilibrium between particle stability and efficiency of cell entry. In this study, we genetically perturb this equilibrium in a non-enveloped virus, enterovirus A71 to determine its structural basis. We isolate a single-point mutation variant with increased particle thermotolerance and decreased efficiency of cell entry. Using cryo-electron microscopy and molecular dynamics simulations, we determine that the thermostable native particles have acquired an expanded conformation that results in a significant increase in protein dynamics. Examining the intermediate states of the thermostable variant reveals a potential pathway for uncoating. We propose a sequential release of the lipid pocket factor, followed by internal VP4 and ultimately the viral RNA.
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Affiliation(s)
- Adam Catching
- Department of Microbiology and Immunology, University of California in San Francisco, San Francisco, CA, 94158, USA
- Graduate Program in Biophysics, University of California in San Francisco, San Francisco, CA, 94158, USA
| | - Ming Te Yeh
- Department of Microbiology and Immunology, University of California in San Francisco, San Francisco, CA, 94158, USA
| | - Simone Bianco
- Industrial and Applied Genomics, AI and Cognitive Software, IBM Almaden Research Center, San Jose, CA, 95120, USA
- Center for Cellular Construction, San Francisco, CA, 94158, USA
- Altos Labs, Redwood City, CA, 94022, USA
| | - Sara Capponi
- Industrial and Applied Genomics, AI and Cognitive Software, IBM Almaden Research Center, San Jose, CA, 95120, USA.
- Center for Cellular Construction, San Francisco, CA, 94158, USA.
| | - Raul Andino
- Department of Microbiology and Immunology, University of California in San Francisco, San Francisco, CA, 94158, USA.
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4
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Singh K, Mehta D, Dumka S, Chauhan AS, Kumar S. Quasispecies Nature of RNA Viruses: Lessons from the Past. Vaccines (Basel) 2023; 11:308. [PMID: 36851186 PMCID: PMC9963406 DOI: 10.3390/vaccines11020308] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/22/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
Viral quasispecies are distinct but closely related mutants formed by the disparity in viral genomes due to recombination, mutations, competition, and selection pressure. Theoretical derivation for the origin of a quasispecies is owed to the error-prone replication by polymerase and mutants of RNA replicators. Here, we briefly addressed the theoretical and mathematical origin of quasispecies and their dynamics. The impact of quasispecies for major salient human pathogens is reviewed. In the current global scenario, rapid changes in geographical landscapes favor the origin and selection of mutants. It comes as no surprise that a cauldron of mutants poses a significant risk to public health, capable of causing pandemics. Mutation rates in RNA viruses are magnitudes higher than in DNA organisms, explaining their enhanced virulence and evolvability. RNA viruses cause the most devastating pandemics; for example, members of the Orthomyxoviridae family caused the great influenza pandemic (1918 flu or Spanish flu), the SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome) outbreak, and the human immunodeficiency viruses (HIV), lentiviruses of the Retroviridae family, caused worldwide devastation. Rapidly evolving RNA virus populations are a daunting challenge for the designing of effective control measures like vaccines. Developing awareness of the evolutionary dispositions of RNA viral mutant spectra and what influences their adaptation and virulence will help curtail outbreaks of past and future pathogens.
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Affiliation(s)
| | | | | | | | - Sachin Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, India
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5
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Strobel HM, Stuart EC, Meyer JR. A Trait-Based Approach to Predicting Viral Host-Range Evolvability. Annu Rev Virol 2022; 9:139-156. [PMID: 36173699 DOI: 10.1146/annurev-virology-091919-092003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Predicting the evolution of virus host range has proven to be extremely difficult, in part because of the sheer diversity of viruses, each with unique biology and ecological interactions. We have not solved this problem, but to make the problem more tractable, we narrowed our focus to three traits intrinsic to all viruses that may play a role in host-range evolvability: mutation rate, recombination rate, and phenotypic heterogeneity. Although each trait should increase evolvability, they cannot do so unbounded because fitness trade-offs limit the ability of all three traits to maximize evolvability. By examining these constraints, we can begin to identify groups of viruses with suites of traits that make them especially concerning, as well as ecological and environmental conditions that might push evolution toward accelerating host-range expansion.
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Affiliation(s)
- Hannah M Strobel
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA;
| | - Elizabeth C Stuart
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA;
| | - Justin R Meyer
- Division of Biological Sciences, University of California, San Diego, La Jolla, California, USA;
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6
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Diaz Arenas C, Ardaševa A, Miller J, Mikheyev AS, Yokobayashi Y. Ribozyme Mutagenic Evolution: Mechanisms of Survival. ORIGINS LIFE EVOL B 2022; 51:321-339. [PMID: 34994918 DOI: 10.1007/s11084-021-09617-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 11/16/2021] [Indexed: 11/24/2022]
Abstract
Primeval populations replicating at high error rates required a mechanism to overcome the accumulation of mutations and information deterioration. Known strategies to overcome mutation pressures include RNA processivity, epistasis, selection, and quasispecies. We investigated the mechanism by which small molecular ribozyme populations can survive under high error rates by propagating several lineages under different mutagen concentrations. We found that every population that evolved without mutagen went extinct, while those subjected to mutagenic evolution survived. To understand how they survived, we characterized the evolved genotypic diversity, the formation of genotype-genotype interaction networks, the fitness of the most common mutants for each enzymatic step, and changes in population size along the course of evolution. We found that the elevated mutation rate was necessary for the populations to survive in the novel environment, in which all the steps of the metabolism worked to promote the survival of even less catalytically efficient ligases. Besides, an increase in population size and the mutational coupling of genotypes in close-knit networks, which helped maintain or recover lost genotypes making their disappearance transient, prevented Muller's ratchet and extinction.
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Affiliation(s)
- Carolina Diaz Arenas
- Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa Prefecture, Japan. .,Yale University, New Haven, CT, USA.
| | - Aleksandra Ardaševa
- Wolfson Centre for Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, UK
| | - Jonathan Miller
- Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa Prefecture, Japan
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa Prefecture, Japan.,Evolutionary Genomics Lab, Research School of Biology, Australian National University, Canberra, Australia
| | - Yohei Yokobayashi
- Okinawa Institute of Science and Technology Graduate University (OIST), Okinawa Prefecture, Japan
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7
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Suryawanshi YR, Nace RA, Russell SJ, Schulze AJ. MicroRNA-detargeting proves more effective than leader gene deletion for improving safety of oncolytic Mengovirus in a nude mouse model. Mol Ther Oncolytics 2021; 23:1-13. [PMID: 34589580 PMCID: PMC8455367 DOI: 10.1016/j.omto.2021.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 08/19/2021] [Indexed: 12/22/2022] Open
Abstract
A dual microRNA-detargeted oncolytic Mengovirus, vMC24NC, proved highly effective against a murine plasmacytoma in an immunocompetent syngeneic mouse model; however, there remains the concern of escape mutant development and the potential for toxicity in severely immunocompromised cancer patients when it is used as an oncolytic virus. Therefore, we sought to compare the safety and efficacy profiles of an attenuated Mengovirus containing a virulence gene deletion versus vMC24NC in an immunodeficient xenograft mouse model of human glioblastoma. A Mengovirus construct, vMC24ΔL, wherein the gene coding for the leader protein, a virulence factor, was deleted, was used for comparison. The vMC24ΔL induced significant levels of toxicity following treatment of subcutaneous human glioblastoma (U87-MG) xenografts as well as when injected intracranially in athymic nude mice, reducing the overall survival. The in vivo toxicity of vMC24ΔL was associated with viral replication in nervous and cardiac tissue. In contrast, microRNA-detargeted vMC24NC demonstrated excellent efficacy against U87-MG subcutaneous xenografts and improved overall survival significantly compared to that of control mice without toxicity. These results reinforce microRNA-detargeting as an effective strategy for ameliorating unwanted toxicities of oncolytic picornaviruses and substantiate vMC24NC as an ideal candidate for clinical development against certain cancers in both immunocompetent and immunodeficient hosts.
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Affiliation(s)
- Yogesh R. Suryawanshi
- Department of Molecular Medicine, Mayo Clinic College of Medicine, 200 1 Street S.W., Rochester, MN 55905, USA
| | - Rebecca A. Nace
- Department of Molecular Medicine, Mayo Clinic College of Medicine, 200 1 Street S.W., Rochester, MN 55905, USA
| | - Stephen J. Russell
- Department of Molecular Medicine, Mayo Clinic College of Medicine, 200 1 Street S.W., Rochester, MN 55905, USA
- Division of Hematology, Mayo Clinic, Rochester, MN 55905, USA
| | - Autumn J. Schulze
- Department of Molecular Medicine, Mayo Clinic College of Medicine, 200 1 Street S.W., Rochester, MN 55905, USA
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8
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Van Eyndhoven LC, Singh A, Tel J. Decoding the dynamics of multilayered stochastic antiviral IFN-I responses. Trends Immunol 2021; 42:824-839. [PMID: 34364820 DOI: 10.1016/j.it.2021.07.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/11/2021] [Accepted: 07/11/2021] [Indexed: 12/11/2022]
Abstract
Type I Interferon (IFN-I) responses were first recognized for their role in antiviral immunity, but it is now widely appreciated that IFN-Is have many immunomodulatory functions, influencing antitumor responses, autoimmune manifestations, and antimicrobial defenses. Given these pivotal roles, it may be surprising that multilayered stochastic events create highly heterogeneous, but tightly regulated, all-or-nothing cellular decisions. Recently, mathematical models have provided crucial insights into the stochastic nature of antiviral IFN-I responses, which we critically evaluate in this review. In this context, we emphasize the need for innovative single-cell technologies combined with mathematical models to further reveal, understand, and predict the complexity of the IFN-I system in physiological and pathological conditions that may be relevant to a plethora of diseases.
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Affiliation(s)
- Laura C Van Eyndhoven
- Laboratory of Immunoengineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, USA
| | - Jurjen Tel
- Laboratory of Immunoengineering, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands; Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands.
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9
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Merleau NSC, Pénisson S, Gerrish PJ, Elena SF, Smerlak M. Why are viral genomes so fragile? The bottleneck hypothesis. PLoS Comput Biol 2021; 17:e1009128. [PMID: 34237053 PMCID: PMC8291636 DOI: 10.1371/journal.pcbi.1009128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 07/20/2021] [Accepted: 05/28/2021] [Indexed: 11/29/2022] Open
Abstract
If they undergo new mutations at each replication cycle, why are RNA viral genomes so fragile, with most mutations being either strongly deleterious or lethal? Here we provide theoretical and numerical evidence for the hypothesis that genetic fragility is partly an evolutionary response to the multiple population bottlenecks experienced by viral populations at various stages of their life cycles. Modelling within-host viral populations as multi-type branching processes, we show that mutational fragility lowers the rate at which Muller’s ratchet clicks and increases the survival probability through multiple bottlenecks. In the context of a susceptible-exposed-infectious-recovered epidemiological model, we find that the attack rate of fragile viral strains can exceed that of more robust strains, particularly at low infectivities and high mutation rates. Our findings highlight the importance of demographic events such as transmission bottlenecks in shaping the genetic architecture of viral pathogens. Given that most mutations are deleterious, high mutation rates carry a significant evolutionary cost. To reduce this burden, an obvious evolutionary solution would be to reduce the fitness cost of mutations by becoming more robust; this solution is indeed selected in populations of constantly large size. Here, we show that when populations regularly experience bottlenecks, as viruses do upon transmission to a new host, a less obvious solution becomes more viable: namely, to increase the fitness cost of mutations so that unfit mutants are less likely to fix at each passage. This could explain why viruses—especially RNA viruses—do in fact have very fragile genomes.
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Affiliation(s)
| | - Sophie Pénisson
- Université Paris Est Créteil, CNRS, LAMA, Creteil, France
- Université Gustave Eiffel, LAMA, Marne-la-Vallée, France
| | - Philip J. Gerrish
- University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Santiago F. Elena
- Instituto de Biología Integrativa de Sistemas (ISysBio), CSIC-Universitat de València, València, Spain
- Santa Fe Institute, Santa Fe, New Mexico, United States of America
| | - Matteo Smerlak
- Max Planck Institute for Mathematics in the Sciences, Leipzig, Germany
- * E-mail:
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10
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Singhal S, Turner PE. Effects of historical co-infection on host shift abilities of exploitative and competitive viruses. Evolution 2021; 75:1878-1888. [PMID: 33969482 PMCID: PMC12058955 DOI: 10.1111/evo.14263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 04/03/2021] [Accepted: 04/16/2021] [Indexed: 12/29/2022]
Abstract
Rapid evolution contributes to frequent emergence of RNA viral pathogens on novel hosts. However, accurately predicting which viral genotypes will emerge has been elusive. Prior work with lytic RNA bacteriophage ɸ6 (family Cystoviridae) suggested that evolution under low multiplicity of infection (MOI; proportion of viruses to susceptible cells) selected for greater host exploitation, while evolution under high MOI selected for better intracellular competition against co-infecting viruses. We predicted that phage genotypes that had experienced 300 generations of low MOI ecological history would be relatively advantaged in initial growth on two novel hosts. We inferred viral growth through changes in host population density, specifically by analyzing five attributes of growth curves of infected bacteria. Despite equivalent growth of evolved viruses on the original host, low MOI evolved clones were generally advantaged relative to high MOI clones in exploiting novel hosts. However, the specific attributes of growth curves that supported their advantage differed by host, indicating interactions between both viral and host genotype. Although there will be host specificity in viral growth, we suggest based on infectivity differences of viruses from high versus low MOI histories that prior MOI selection can later affect emergence potential.
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Affiliation(s)
- Sonia Singhal
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520, USA
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan 48824, USA
- Current affiliation: Department of Biological Sciences, San José Sate University, San José, California 95192, USA
| | - Paul E. Turner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut 06520, USA
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan 48824, USA
- Graduate Program in Microbiology, Yale School of Medicine, New Haven, Connecticut 06520, USA
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11
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Intra-host evolutionary dynamics of the hepatitis C virus among people who inject drugs. Sci Rep 2021; 11:9986. [PMID: 33976241 PMCID: PMC8113533 DOI: 10.1038/s41598-021-88132-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/31/2021] [Indexed: 02/03/2023] Open
Abstract
Most individuals chronically infected with hepatitis C virus (HCV) are asymptomatic during the initial stages of infection and therefore the precise timing of infection is often unknown. Retrospective estimation of infection duration would improve existing surveillance data and help guide treatment. While intra-host viral diversity quantifications such as Shannon entropy have previously been utilized for estimating duration of infection, these studies characterize the viral population from only a relatively short segment of the HCV genome. In this study intra-host diversities were examined across the HCV genome in order to identify the region most reflective of time and the degree to which these estimates are influenced by high-risk activities including those associated with HCV acquisition. Shannon diversities were calculated for all regions of HCV from 78 longitudinally sampled individuals with known seroconversion timeframes. While the region of the HCV genome most accurately reflecting time resided within the NS3 gene, the gene region with the highest capacity to differentiate acute from chronic infections was identified within the NS5b region. Multivariate models predicting duration of infection from viral diversity significantly improved upon incorporation of variables associated with recent public, unsupervised drug use. These results could assist the development of strategic population treatment guidelines for high-risk individuals infected with HCV and offer insights into variables associated with a likelihood of transmission.
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12
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Novelli G, Biancolella M, Mehrian-Shai R, Colona VL, Brito AF, Grubaugh ND, Vasiliou V, Luzzatto L, Reichardt JKV. COVID-19 one year into the pandemic: from genetics and genomics to therapy, vaccination, and policy. Hum Genomics 2021; 15:27. [PMID: 33966626 PMCID: PMC8107019 DOI: 10.1186/s40246-021-00326-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/15/2021] [Indexed: 12/14/2022] Open
Abstract
COVID-19 has engulfed the world and it will accompany us all for some time to come. Here, we review the current state at the milestone of 1 year into the pandemic, as declared by the WHO (World Health Organization). We review several aspects of the on-going pandemic, focusing first on two major topics: viral variants and the human genetic susceptibility to disease severity. We then consider recent and exciting new developments in therapeutics, such as monoclonal antibodies, and in prevention strategies, such as vaccines. We also briefly discuss how advances in basic science and in biotechnology, under the threat of a worldwide emergency, have accelerated to an unprecedented degree of the transition from the laboratory to clinical applications. While every day we acquire more and more tools to deal with the on-going pandemic, we are aware that the path will be arduous and it will require all of us being community-minded. In this respect, we lament past delays in timely full investigations, and we call for bypassing local politics in the interest of humankind on all continents.
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Affiliation(s)
- Giuseppe Novelli
- Department of Biomedicine and Prevention, "Tor Vergata" University of Rome, 00133, Rome, Italy.
- IRCCS Neuromed, Pozzilli, IS, Italy.
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, NV, 89557, USA.
| | | | - Ruty Mehrian-Shai
- Pediatric Hemato-Oncology, Sheba Medical Center, Tel Hashomer, Israel
| | - Vito Luigi Colona
- Department of Biomedicine and Prevention, "Tor Vergata" University of Rome, 00133, Rome, Italy
| | - Anderson F Brito
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Nathan D Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Lucio Luzzatto
- Haematology, Muhimbili University of Health and Allied Sciences, Dar-es Salaam, Tanzania
| | - Juergen K V Reichardt
- Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, Queensland, 4878, Australia
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13
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Barlukova A, Rouzine IM. The evolutionary origin of the universal distribution of mutation fitness effect. PLoS Comput Biol 2021; 17:e1008822. [PMID: 33684109 PMCID: PMC7971868 DOI: 10.1371/journal.pcbi.1008822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 03/18/2021] [Accepted: 02/19/2021] [Indexed: 01/27/2023] Open
Abstract
An intriguing fact long defying explanation is the observation of a universal exponential distribution of beneficial mutations in fitness effect for different microorganisms. To explain this effect, we use a population model including mutation, directional selection, linkage, and genetic drift. The multiple-mutation regime of adaptation at large population sizes (traveling wave regime) is considered. We demonstrate analytically and by simulation that, regardless of the inherent distribution of mutation fitness effect across genomic sites, an exponential distribution of fitness effects emerges in the long term. This result follows from the exponential statistics of the frequency of the less-fit alleles, f, that we predict to evolve, in the long term, for both polymorphic and monomorphic sites. We map the logarithmic slope of the distribution onto the previously derived fixation probability and demonstrate that it increases linearly in time. Our results demonstrate a striking difference between the distribution of fitness effects observed experimentally for naturally occurring mutations, and the "inherent" distribution obtained in a directed-mutagenesis experiment, which can have any shape depending on the organism. Based on these results, we develop a new method to measure the fitness effect of mutations for each variable residue using DNA sequences sampled from adapting populations. This new method is not sensitive to linkage effects and does not require the one-site model assumptions.
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Affiliation(s)
- Ayuna Barlukova
- Sorbonne Université, Institute de Biologie Paris-Seine, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Igor M. Rouzine
- Sorbonne Université, Institute de Biologie Paris-Seine, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
- * E-mail: ,
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14
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Sarkar R, Mitra S, Chandra P, Saha P, Banerjee A, Dutta S, Chawla-Sarkar M. Comprehensive analysis of genomic diversity of SARS-CoV-2 in different geographic regions of India: an endeavour to classify Indian SARS-CoV-2 strains on the basis of co-existing mutations. Arch Virol 2021; 166:801-812. [PMID: 33464421 PMCID: PMC7814186 DOI: 10.1007/s00705-020-04911-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/21/2020] [Indexed: 01/24/2023]
Abstract
Accumulation of mutations within the genome is the primary driving force in viral evolution within an endemic setting. This inherent feature often leads to altered virulence, infectivity and transmissibility, and antigenic shifts to escape host immunity, which might compromise the efficacy of vaccines and antiviral drugs. Therefore, we carried out a genome-wide analysis of circulating SARS-CoV-2 strains to detect the emergence of novel co-existing mutations and trace their geographical distribution within India. Comprehensive analysis of whole genome sequences of 837 Indian SARS-CoV-2 strains revealed the occurrence of 33 different mutations, 18 of which were unique to India. Novel mutations were observed in the S glycoprotein (6/33), NSP3 (5/33), RdRp/NSP12 (4/33), NSP2 (2/33), and N (1/33). Non-synonymous mutations were found to be 3.07 times more prevalent than synonymous mutations. We classified the Indian isolates into 22 groups based on their co-existing mutations. Phylogenetic analysis revealed that the representative strains of each group were divided into various sub-clades within their respective clades, based on the presence of unique co-existing mutations. The A2a clade was found to be dominant in India (71.34%), followed by A3 (23.29%) and B (5.36%), but a heterogeneous distribution was observed among various geographical regions. The A2a clade was highly predominant in East India, Western India, and Central India, whereas the A2a and A3 clades were nearly equal in prevalence in South and North India. This study highlights the divergent evolution of SARS-CoV-2 strains and co-circulation of multiple clades in India. Monitoring of the emerging mutations will pave the way for vaccine formulation and the design of antiviral drugs.
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Affiliation(s)
- Rakesh Sarkar
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Suvrotoa Mitra
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Pritam Chandra
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Priyanka Saha
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Anindita Banerjee
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Shanta Dutta
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India
| | - Mamta Chawla-Sarkar
- Division of Virology, National Institute of Cholera and Enteric Diseases, P-33, C.I.T. Road, Scheme-XM, Beliaghata, Kolkata, West Bengal, 700010, India.
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15
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Rouzine IM. An Evolutionary Model of Progression to AIDS. Microorganisms 2020; 8:microorganisms8111714. [PMID: 33142907 PMCID: PMC7692852 DOI: 10.3390/microorganisms8111714] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/30/2020] [Accepted: 10/30/2020] [Indexed: 11/16/2022] Open
Abstract
The time to the onset of AIDS symptoms in an HIV infected individual is known to correlate inversely with viremia and the level of immune activation. The correlation exists against the background of strong individual fluctuations demonstrating the existence of hidden variables depending on patient and virus parameters. At the moment, prognosis of the time to AIDS based on patient parameters is not possible. In addition, it is of paramount importance to understand the reason of progression to AIDS in untreated patients to be able to learn to control it by means other than anti-retroviral therapy. Here we develop a mechanistic mathematical model to predict the speed of progression to AIDS in individual untreated patients and patients treated with suboptimal therapy, based on a single-time measurement of several virological and immunological parameters. We show that the gradual increase in virus fitness during a chronic infection causes slow gradual depletion of CD4 T cells. Using the existing evolution models of HIV, we obtain general expressions predicting the time to the onset of AIDS symptoms in terms of the patient parameters, for low-viremia and high-viremia patients separately. We show that the evolution model of AIDS fits the existing data on virus-time correlations better than the alternative model of the deregulation of homeostatic response.
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Affiliation(s)
- Igor M Rouzine
- Laboratory of Computational and Quantitative Biology, 7238 CNRS-UPMC, Institut Biologie Paris-Seine, Sorbonne Université, Campus Pierre et Marie Curie, 75005 Paris, France
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16
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Butković A, González R, Cobo I, Elena SF. Adaptation of turnip mosaic potyvirus to a specific niche reduces its genetic and environmental robustness. Virus Evol 2020; 6:veaa041. [PMID: 32782826 PMCID: PMC7409916 DOI: 10.1093/ve/veaa041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Robustness is the preservation of the phenotype in the face of genetic and environmental perturbations. It has been argued that robustness must be an essential fitness component of RNA viruses owed to their small and compacted genomes, high mutation rates and living in ever-changing environmental conditions. Given that genetic robustness might hamper possible beneficial mutations, it has been suggested that genetic robustness can only evolve as a side-effect of the evolution of robustness mechanisms specific to cope with environmental perturbations, a theory known as plastogenetic congruence. However, empirical evidences from different viral systems are contradictory. To test how adaptation to a particular environment affects both environmental and genetic robustness, we have used two strains of turnip mosaic potyvirus (TuMV) that differ in their degree of adaptation to Arabidopsis thaliana at a permissive temperature. We show that the highly adapted strain is strongly sensitive to the effect of random mutations and to changes in temperature conditions. In contrast, the non-adapted strain shows more robustness against both the accumulation of random mutations and drastic changes in temperature conditions. Together, these results are consistent with the predictions of the plastogenetic congruence theory, suggesting that genetic and environmental robustnesses may be two sides of the same coin for TuMV.
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Affiliation(s)
- Anamarija Butković
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Cientific UV, Catedrático Agustín Escardino 9, Paterna, 46980 Valencia, Spain
| | - Rubén González
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Cientific UV, Catedrático Agustín Escardino 9, Paterna, 46980 Valencia, Spain
| | - Inés Cobo
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Cientific UV, Catedrático Agustín Escardino 9, Paterna, 46980 Valencia, Spain
| | - Santiago F Elena
- Instituto de Biología Integrativa de Sistemas (I2SysBio), CSIC-Universitat de València, Parc Cientific UV, Catedrático Agustín Escardino 9, Paterna, 46980 Valencia, Spain.,The Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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17
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Sexton NR, Ebel GD. Effects of Arbovirus Multi-Host Life Cycles on Dinucleotide and Codon Usage Patterns. Viruses 2019; 11:v11070643. [PMID: 31336898 PMCID: PMC6669465 DOI: 10.3390/v11070643] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 07/09/2019] [Accepted: 07/11/2019] [Indexed: 12/12/2022] Open
Abstract
Arthropod-borne viruses (arboviruses) of vertebrates including dengue, zika, chikungunya, Rift Valley fever, and blue tongue viruses cause extensive morbidity and mortality in humans, agricultural animals, and wildlife across the globe. As obligate intercellular pathogens, arboviruses must be well adapted to the cellular and molecular environment of both their arthropod (invertebrate) and vertebrate hosts, which are vastly different due to hundreds of millions of years of separate evolution. Here we discuss the comparative pressures on arbovirus RNA genomes as a result of a dual host life cycle, focusing on pressures that do not alter amino acids. We summarize what is currently known about arboviral genetic composition, such as dinucleotide and codon usage, and how cyclical infection of vertebrate and invertebrate hosts results in different genetic profiles compared with single-host viruses. To serve as a comparison, we compile what is known about arthropod tRNA, dinucleotide, and codon usages and compare this with vertebrates. Additionally, we discuss the potential roles of genetic robustness in arboviral evolution and how it may vary from other viruses. Overall, both arthropod and vertebrate hosts influence the resulting genetic composition of arboviruses, but a great deal remains to be investigated.
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Affiliation(s)
- Nicole R Sexton
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Gregory D Ebel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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18
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McCarthy C, Jayawardena N, Burga LN, Bostina M. Developing Picornaviruses for Cancer Therapy. Cancers (Basel) 2019; 11:E685. [PMID: 31100962 PMCID: PMC6562951 DOI: 10.3390/cancers11050685] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/02/2019] [Accepted: 05/08/2019] [Indexed: 12/24/2022] Open
Abstract
Oncolytic viruses (OVs) form a group of novel anticancer therapeutic agents which selectively infect and lyse cancer cells. Members of several viral families, including Picornaviridae, have been shown to have anticancer activity. Picornaviruses are small icosahedral non-enveloped, positive-sense, single-stranded RNA viruses infecting a wide range of hosts. They possess several advantages for development for cancer therapy: Their genomes do not integrate into host chromosomes, do not encode oncogenes, and are easily manipulated as cDNA. This review focuses on the picornaviruses investigated for anticancer potential and the mechanisms that underpin this specificity.
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Affiliation(s)
- Cormac McCarthy
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
| | - Nadishka Jayawardena
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
| | - Laura N Burga
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
| | - Mihnea Bostina
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand.
- Otago Micro and Nano Imaging, University of Otago, Dunedin 9016, New Zealand.
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19
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Drayman N, Patel P, Vistain L, Tay S. HSV-1 single-cell analysis reveals the activation of anti-viral and developmental programs in distinct sub-populations. eLife 2019; 8:e46339. [PMID: 31090537 PMCID: PMC6570482 DOI: 10.7554/elife.46339] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 05/11/2019] [Indexed: 12/12/2022] Open
Abstract
Viral infection is usually studied at the population level by averaging over millions of cells. However, infection at the single-cell level is highly heterogeneous, with most infected cells giving rise to no or few viral progeny while some cells produce thousands. Analysis of Herpes Simplex virus 1 (HSV-1) infection by population-averaged measurements has taught us a lot about the course of viral infection, but has also produced contradictory results, such as the concurrent activation and inhibition of type I interferon signaling during infection. Here, we combine live-cell imaging and single-cell RNA sequencing to characterize viral and host transcriptional heterogeneity during HSV-1 infection of primary human cells. We find extreme variability in the level of viral gene expression among individually infected cells and show that these cells cluster into transcriptionally distinct sub-populations. We find that anti-viral signaling is initiated in a rare group of abortively infected cells, while highly infected cells undergo cellular reprogramming to an embryonic-like transcriptional state. This reprogramming involves the recruitment of β-catenin to the host nucleus and viral replication compartments, and is required for late viral gene expression and progeny production. These findings uncover the transcriptional differences in cells with variable infection outcomes and shed new light on the manipulation of host pathways by HSV-1.
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Affiliation(s)
- Nir Drayman
- Institute for Molecular EngineeringThe University of ChicagoChicagoUnited States
- Institute for Genomics and Systems BiologyThe University of ChicagoChicagoUnited States
| | - Parthiv Patel
- Institute for Molecular EngineeringThe University of ChicagoChicagoUnited States
- Institute for Genomics and Systems BiologyThe University of ChicagoChicagoUnited States
| | - Luke Vistain
- Institute for Molecular EngineeringThe University of ChicagoChicagoUnited States
- Institute for Genomics and Systems BiologyThe University of ChicagoChicagoUnited States
| | - Savaş Tay
- Institute for Molecular EngineeringThe University of ChicagoChicagoUnited States
- Institute for Genomics and Systems BiologyThe University of ChicagoChicagoUnited States
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20
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Zhao L, Abbasi AB, Illingworth CJR. Mutational load causes stochastic evolutionary outcomes in acute RNA viral infection. Virus Evol 2019; 5:vez008. [PMID: 31024738 PMCID: PMC6476161 DOI: 10.1093/ve/vez008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mutational load is known to be of importance for the evolution of RNA viruses, the combination of a high mutation rate and large population size leading to an accumulation of deleterious mutations. However, while the effects of mutational load on global viral populations have been considered, its quantitative effects at the within-host scale of infection are less well understood. We here show that even on the rapid timescale of acute disease, mutational load has an effect on within-host viral adaptation, reducing the effective selection acting upon beneficial variants by ∼10 per cent. Furthermore, mutational load induces considerable stochasticity in the pattern of evolution, causing a more than five-fold uncertainty in the effective fitness of a transmitted beneficial variant. Our work aims to bridge the gap between classic models from population genetic theory and the biology of viral infection. In an advance on some previous models of mutational load, we replace the assumption of a constant variant fitness cost with an experimentally-derived distribution of fitness effects. Expanding previous frameworks for evolutionary simulation, we introduce the Wright-Fisher model with continuous mutation, which describes a continuum of possible modes of replication within a cell. Our results advance our understanding of adaptation in the context of strong selection and a high mutation rate. Despite viral populations having large absolute sizes, critical events in viral adaptation, including antigenic drift and the onset of drug resistance, arise through stochastic evolutionary processes.
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Affiliation(s)
- Lei Zhao
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Ali B Abbasi
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Christopher J R Illingworth
- Department of Genetics, University of Cambridge, Cambridge, UK
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
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21
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Zinger T, Gelbart M, Miller D, Pennings PS, Stern A. Inferring population genetics parameters of evolving viruses using time-series data. Virus Evol 2019; 5:vez011. [PMID: 31191979 PMCID: PMC6555871 DOI: 10.1093/ve/vez011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
With the advent of deep sequencing techniques, it is now possible to track the evolution of viruses with ever-increasing detail. Here, we present Flexible Inference from Time-Series (FITS)-a computational tool that allows inference of one of three parameters: the fitness of a specific mutation, the mutation rate or the population size from genomic time-series sequencing data. FITS was designed first and foremost for analysis of either short-term Evolve & Resequence (E&R) experiments or rapidly recombining populations of viruses. We thoroughly explore the performance of FITS on simulated data and highlight its ability to infer the fitness/mutation rate/population size. We further show that FITS can infer meaningful information even when the input parameters are inexact. In particular, FITS is able to successfully categorize a mutation as advantageous or deleterious. We next apply FITS to empirical data from an E&R experiment on poliovirus where parameters were determined experimentally and demonstrate high accuracy in inference.
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Affiliation(s)
- Tal Zinger
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Haim Levanon Str., Tel-Aviv University, Tel-Aviv, Israel
| | - Maoz Gelbart
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Haim Levanon Str., Tel-Aviv University, Tel-Aviv, Israel
| | - Danielle Miller
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Haim Levanon Str., Tel-Aviv University, Tel-Aviv, Israel
| | - Pleuni S Pennings
- Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA, USA
| | - Adi Stern
- Department of Molecular Microbiology and Biotechnology, School of Molecular Cell Biology and Biotechnology, Haim Levanon Str., Tel-Aviv University, Tel-Aviv, Israel
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22
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Dolan PT, Whitfield ZJ, Andino R. Mechanisms and Concepts in RNA Virus Population Dynamics and Evolution. Annu Rev Virol 2018; 5:69-92. [PMID: 30048219 DOI: 10.1146/annurev-virology-101416-041718] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RNA viruses are unique in their evolutionary capacity, exhibiting high mutation rates and frequent recombination. They rapidly adapt to environmental changes, such as shifts in immune pressure or pharmacological challenge. The evolution of RNA viruses has been brought into new focus with the recent developments of genetic and experimental tools to explore and manipulate the evolutionary dynamics of viral populations. These studies have uncovered new mechanisms that enable viruses to overcome evolutionary challenges in the environment and have emphasized the intimate relationship of viral populations with evolution. Here, we review some of the emerging viral and host mechanisms that underlie the evolution of RNA viruses. We also discuss new studies that demonstrate that the relationship between evolutionary dynamics and virus biology spans many spatial and temporal scales, affecting transmission dynamics within and between hosts as well as pathogenesis.
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Affiliation(s)
- Patrick T Dolan
- Department of Biology, Stanford University, Stanford, California 94305, USA.,Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA;
| | - Zachary J Whitfield
- Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA;
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, California 94143, USA;
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23
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Abstract
The deterministic force of natural selection and stochastic influence of drift shape RNA virus evolution. New deep-sequencing and microfluidics technologies allow us to quantify the effect of mutations and trace the evolution of viral populations with single-genome and single-nucleotide resolution. Such experiments can reveal the topography of the genotype-fitness landscapes that shape the path of viral evolution. By combining historical analyses, like phylogenetic approaches, with high-throughput and high-resolution evolutionary experiments, we can observe parallel patterns of evolution that drive important phenotypic transitions. These developments provide a framework for quantifying and anticipating potential evolutionary events. Here, we examine emerging technologies that can map the selective landscapes of viruses, focusing on their application to pathogenic viruses. We identify areas where these technologies can bolster our ability to study the evolution of viruses and to anticipate and possibly intervene in evolutionary events and prevent viral disease.
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Affiliation(s)
- Patrick T Dolan
- Department of Biology, Stanford University, E200 Clark Center, 318 Campus Drive, Stanford, CA 94305, USA; Department of Microbiology and Immunology, University of California, San Francisco, 600 16th Street, GH-S572, UCSF Box 2280, San Francisco, CA 94143-2280, USA
| | - Zachary J Whitfield
- Department of Microbiology and Immunology, University of California, San Francisco, 600 16th Street, GH-S572, UCSF Box 2280, San Francisco, CA 94143-2280, USA
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, 600 16th Street, GH-S572, UCSF Box 2280, San Francisco, CA 94143-2280, USA.
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24
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Abstract
Reproduction of RNA viruses is typically error-prone due to the infidelity of their replicative machinery and the usual lack of proofreading mechanisms. The error rates may be close to those that kill the virus. Consequently, populations of RNA viruses are represented by heterogeneous sets of genomes with various levels of fitness. This is especially consequential when viruses encounter various bottlenecks and new infections are initiated by a single or few deviating genomes. Nevertheless, RNA viruses are able to maintain their identity by conservation of major functional elements. This conservatism stems from genetic robustness or mutational tolerance, which is largely due to the functional degeneracy of many protein and RNA elements as well as to negative selection. Another relevant mechanism is the capacity to restore fitness after genetic damages, also based on replicative infidelity. Conversely, error-prone replication is a major tool that ensures viral evolvability. The potential for changes in debilitated genomes is much higher in small populations, because in the absence of stronger competitors low-fit genomes have a choice of various trajectories to wander along fitness landscapes. Thus, low-fit populations are inherently unstable, and it may be said that to run ahead it is useful to stumble. In this report, focusing on picornaviruses and also considering data from other RNA viruses, we review the biological relevance and mechanisms of various alterations of viral RNA genomes as well as pathways and mechanisms of rehabilitation after loss of fitness. The relationships among mutational robustness, resilience, and evolvability of viral RNA genomes are discussed.
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25
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Drayman N, Karin O, Mayo A, Danon T, Shapira L, Rafael D, Zimmer A, Bren A, Kobiler O, Alon U. Dynamic Proteomics of Herpes Simplex Virus Infection. mBio 2017; 8:e01612-17. [PMID: 29114028 PMCID: PMC5676043 DOI: 10.1128/mbio.01612-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Accepted: 10/06/2017] [Indexed: 12/28/2022] Open
Abstract
The cellular response to viral infection is usually studied at the level of cell populations. Currently, it remains an open question whether and to what extent cell-to-cell variability impacts the course of infection. Here we address this by dynamic proteomics-imaging and tracking 400 yellow fluorescent protein (YFP)-tagged host proteins in individual cells infected by herpes simplex virus 1. By quantifying time-lapse fluorescence imaging, we analyze how cell-to-cell variability impacts gene expression from the viral genome. We identify two proteins, RFX7 and geminin, whose levels at the time of infection correlate with successful initiation of gene expression. These proteins are cell cycle markers, and we find that the position in the cell cycle at the time of infection (along with the cell motility and local cell density) can reasonably predict in which individual cells gene expression from the viral genome will commence. We find that the onset of cell division dramatically impacts the progress of infection, with 70% of dividing cells showing no additional gene expression after mitosis. Last, we identify four host proteins that are specifically modulated in infected cells, of which only one has been previously recognized. SUMO2 and RPAP3 levels are rapidly reduced, while SLTM and YTHDC1 are redistributed to form nuclear foci. These modulations are dependent on the expression of ICP0, as shown by infection with two mutant viruses that lack ICP0. Taken together, our results provide experimental validation for the long-held notion that the success of infection is dependent on the state of the host cell at the time of infection.IMPORTANCE High-throughput assays have revolutionized many fields in biology, both by allowing a more global understanding of biological processes and by deciphering rare events in subpopulations. Here we use such an assay, dynamic proteomics, to study viral infection at the single-cell level. We follow tens of thousands of individual cells infected by herpes simplex virus using fluorescence live imaging. Our results link the state of a cell at the time of virus infection with its probability to successfully initiate gene expression from the viral genome. Further, we identified three cellular proteins that were previously unknown to respond to viral infection. We conclude that dynamic proteomics provides a powerful tool to study single-cell differences during viral infection.
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Affiliation(s)
- Nir Drayman
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Omer Karin
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Avi Mayo
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Tamar Danon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Lev Shapira
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dor Rafael
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Anat Zimmer
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Anat Bren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oren Kobiler
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Uri Alon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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26
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Jerison ER, Kryazhimskiy S, Mitchell JK, Bloom JS, Kruglyak L, Desai MM. Genetic variation in adaptability and pleiotropy in budding yeast. eLife 2017; 6:27167. [PMID: 28826486 PMCID: PMC5580887 DOI: 10.7554/elife.27167] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 08/14/2017] [Indexed: 12/25/2022] Open
Abstract
Evolution can favor organisms that are more adaptable, provided that genetic variation in adaptability exists. Here, we quantify this variation among 230 offspring of a cross between diverged yeast strains. We measure the adaptability of each offspring genotype, defined as its average rate of adaptation in a specific environmental condition, and analyze the heritability, predictability, and genetic basis of this trait. We find that initial genotype strongly affects adaptability and can alter the genetic basis of future evolution. Initial genotype also affects the pleiotropic consequences of adaptation for fitness in a different environment. This genetic variation in adaptability and pleiotropy is largely determined by initial fitness, according to a rule of declining adaptability with increasing initial fitness, but several individual QTLs also have a significant idiosyncratic role. Our results demonstrate that both adaptability and pleiotropy are complex traits, with extensive heritable differences arising from naturally occurring variation.
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Affiliation(s)
- Elizabeth R Jerison
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, United States.,Department of Physics, Harvard University, Cambridge, United States.,FAS Center for Systems Biology, Harvard University, Cambridge, United States
| | - Sergey Kryazhimskiy
- Section of Ecology, Behavior and Evolution, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | | | - Joshua S Bloom
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Leonid Kruglyak
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Michael M Desai
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, United States.,Department of Physics, Harvard University, Cambridge, United States.,FAS Center for Systems Biology, Harvard University, Cambridge, United States
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27
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Stern A, Yeh MT, Zinger T, Smith M, Wright C, Ling G, Nielsen R, Macadam A, Andino R. The Evolutionary Pathway to Virulence of an RNA Virus. Cell 2017; 169:35-46.e19. [PMID: 28340348 DOI: 10.1016/j.cell.2017.03.013] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 01/03/2017] [Accepted: 03/06/2017] [Indexed: 12/31/2022]
Abstract
Paralytic polio once afflicted almost half a million children each year. The attenuated oral polio vaccine (OPV) has enabled world-wide vaccination efforts, which resulted in nearly complete control of the disease. However, poliovirus eradication is hampered globally by epidemics of vaccine-derived polio. Here, we describe a combined theoretical and experimental strategy that describes the molecular events leading from OPV to virulent strains. We discover that similar evolutionary events occur in most epidemics. The mutations and the evolutionary trajectories driving these epidemics are replicated using a simple cell-based experimental setup where the rate of evolution is intentionally accelerated. Furthermore, mutations accumulating during epidemics increase the replication fitness of the virus in cell culture and increase virulence in an animal model. Our study uncovers the evolutionary strategies by which vaccine strains become pathogenic and provides a powerful framework for rational design of safer vaccine strains and for forecasting virulence of viruses. VIDEO ABSTRACT.
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Affiliation(s)
- Adi Stern
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv 6997801, Israel.
| | - Ming Te Yeh
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Tal Zinger
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Matt Smith
- Division of Virology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK
| | - Caroline Wright
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Guy Ling
- Department of Molecular Microbiology and Biotechnology, Tel-Aviv University, Tel-Aviv 6997801, Israel
| | - Rasmus Nielsen
- Department of Integrative Biology; Department of Statistics, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Andrew Macadam
- Division of Virology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire, EN6 3QG, UK
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA.
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28
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Moratorio G, Henningsson R, Barbezange C, Carrau L, Bordería AV, Blanc H, Beaucourt S, Poirier EZ, Vallet T, Boussier J, Mounce BC, Fontes M, Vignuzzi M. Attenuation of RNA viruses by redirecting their evolution in sequence space. Nat Microbiol 2017; 2:17088. [PMID: 28581455 PMCID: PMC7098180 DOI: 10.1038/nmicrobiol.2017.88] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 04/27/2017] [Indexed: 12/18/2022]
Abstract
RNA viruses pose serious threats to human health. Their success relies on their capacity to generate genetic variability and, consequently, on their adaptive potential. We describe a strategy to attenuate RNA viruses by altering their evolutionary potential. We rationally altered the genomes of Coxsackie B3 and influenza A viruses to redirect their evolutionary trajectories towards detrimental regions in sequence space. Specifically, viral genomes were engineered to harbour more serine and leucine codons with nonsense mutation targets: codons that could generate Stop mutations after a single nucleotide substitution. Indeed, these viruses generated more Stop mutations both in vitro and in vivo, accompanied by significant losses in viral fitness. In vivo, the viruses were attenuated, generated high levels of neutralizing antibodies and protected against lethal challenge. Our study demonstrates that cornering viruses in ‘risky’ areas of sequence space may be implemented as a broad-spectrum vaccine strategy against RNA viruses. Virus attenuation is used to obtain vaccine strains. Here, the rapid evolution of RNA viruses is exploited by engineering their genomes to encode sites that are a mutation away from a stop codon, a clever method to generate attenuated viruses.
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Affiliation(s)
- Gonzalo Moratorio
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Rasmus Henningsson
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,International Group for Data Analysis, Institut Pasteur, C3BI, USR 3756 IP CNRS, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,Centre for Mathematical Sciences, Lund University, 22100 Lund, Sweden
| | - Cyril Barbezange
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Lucia Carrau
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,Sorbonne Paris Cité, Université Paris Diderot, Cellule Pasteur, 75013 Paris, France
| | - Antonio V Bordería
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,International Group for Data Analysis, Institut Pasteur, C3BI, USR 3756 IP CNRS, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Hervé Blanc
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Stephanie Beaucourt
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Enzo Z Poirier
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,Sorbonne Paris Cité, Université Paris Diderot, Cellule Pasteur, 75013 Paris, France
| | - Thomas Vallet
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Jeremy Boussier
- International Group for Data Analysis, Institut Pasteur, C3BI, USR 3756 IP CNRS, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,Unité d'Immunobiologie des Cellules Dendritiques, Institut Pasteur, Inserm 1223, 25 rue du Dr. Roux, 75724 Paris cedex 15, Paris, France.,Ecole doctorale Frontières du vivant, Université Paris Diderot, 75013 Paris, France
| | - Bryan C Mounce
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
| | - Magnus Fontes
- International Group for Data Analysis, Institut Pasteur, C3BI, USR 3756 IP CNRS, 28 rue du Dr. Roux, 75724 Paris cedex 15, France.,Centre for Mathematical Sciences, Lund University, 22100 Lund, Sweden
| | - Marco Vignuzzi
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 28 rue du Dr. Roux, 75724 Paris cedex 15, France
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29
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Variation in Recombination Rate: Adaptive or Not? Trends Genet 2017; 33:364-374. [DOI: 10.1016/j.tig.2017.03.003] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 01/30/2023]
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30
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Minicka J, Elena SF, Borodynko-Filas N, Rubiś B, Hasiów-Jaroszewska B. Strain-dependent mutational effects for Pepino mosaic virus in a natural host. BMC Evol Biol 2017; 17:67. [PMID: 28264646 PMCID: PMC5339997 DOI: 10.1186/s12862-017-0920-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/20/2017] [Indexed: 11/10/2022] Open
Abstract
Background Pepino mosaic virus (PepMV) is an emerging plant pathogen that infects tomatoes worldwide. Understanding the factors that influence its evolutionary success is essential for developing new control strategies that may be more robust against the evolution of new viral strains. One of these evolutionary factors is the distribution of mutational fitness effect (DMFE), that is, the fraction of mutations that are lethal, deleterious, neutral, and beneficial on a given viral strain and host species. The goal of this study was to characterize the DMFE of introduced nonsynonymous mutations on a mild isolate of PepMV from the Chilean 2 strain (PepMV-P22). Additionally, we also explored whether the fitness effect of a given mutation depends on the gene where it appears or on epistatic interactions with the genetic background. To address this latter possibility, a subset of mutations were also introduced in a mild isolate of the European strain (PepMV-P11) and the fitness of the resulting clones measured. Results A collection of 25 PepMV clones each containing a single nucleotide nonsynonymous substitution was created by site-directed mutagenesis and the fitness of each mutant was determined. PepMV-P22 genome showed a high degree of robustness against point mutations, with 80% of mutations being either neutral or even beneficial and only 20% being deleterious or lethal. We found that the effect of mutations strongly depended on the gene in which they were introduced. Mutations with the largest average beneficial effects were those affecting the RdRp gene, in contrast to mutations affecting TGB1 and CP genes, for which the average effects were deleterious. Moreover, significant epistatic interactions were observed between nonsynonymous mutations and the genetic background, meaning that the effect of a given nucleotide substitution on a particular genomic context cannot be predicted by knowing its effect in a different one. Conclusions Our results indicated that PepMV genome has a surprisingly high robustness against mutations. We also found that fitness consequences of a given mutation differ between the two strains analyzed. This discovery suggests that the strength of selection, and thus the rates of evolution, vary among PepMV strains.
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Affiliation(s)
- Julia Minicka
- Department of Virology and Bacteriology, Institute of Plant Protection-National Research Institute, Poznan, Poland
| | - Santiago F Elena
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, València, Spain.,Instituto de Biología Integrativa y de Sistemas, Consejo Superior de Investigaciones Científicas-Universitat de València, València, Spain.,The Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Natasza Borodynko-Filas
- Department of Virology and Bacteriology, Institute of Plant Protection-National Research Institute, Poznan, Poland
| | - Błażej Rubiś
- Department of Clinical Chemistry and Molecular Diagnostics, Poznan University of Medical Sciences, Poznan, Poland
| | - Beata Hasiów-Jaroszewska
- Department of Virology and Bacteriology, Institute of Plant Protection-National Research Institute, Poznan, Poland.
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31
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Xiao Y, Rouzine IM, Bianco S, Acevedo A, Goldstein EF, Farkov M, Brodsky L, Andino R. RNA Recombination Enhances Adaptability and Is Required for Virus Spread and Virulence. Cell Host Microbe 2016; 19:493-503. [PMID: 27078068 DOI: 10.1016/j.chom.2016.03.009] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/13/2016] [Accepted: 03/25/2016] [Indexed: 10/21/2022]
Abstract
Mutation and recombination are central processes driving microbial evolution. A high mutation rate fuels adaptation but also generates deleterious mutations. Recombination between two different genomes may resolve this paradox, alleviating effects of clonal interference and purging deleterious mutations. Here we demonstrate that recombination significantly accelerates adaptation and evolution during acute virus infection. We identified a poliovirus recombination determinant within the virus polymerase, mutation of which reduces recombination rates without altering replication fidelity. By generating a panel of variants with distinct mutation rates and recombination ability, we demonstrate that recombination is essential to enrich the population in beneficial mutations and purge it from deleterious mutations. The concerted activities of mutation and recombination are key to virus spread and virulence in infected animals. These findings inform a mathematical model to demonstrate that poliovirus adapts most rapidly at an optimal mutation rate determined by the trade-off between selection and accumulation of detrimental mutations.
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Affiliation(s)
- Yinghong Xiao
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Igor M Rouzine
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Simone Bianco
- Department of Industrial and Applied Genomics, Accelerated Discovery Lab, IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120-6099, USA
| | - Ashley Acevedo
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Elizabeth Faul Goldstein
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Mikhail Farkov
- Tauber Bioinformatics Research Center and Department of Evolutionary and Environmental Biology, University of Haifa, Mount Carmel, Haifa 31905, Israel
| | - Leonid Brodsky
- Tauber Bioinformatics Research Center and Department of Evolutionary and Environmental Biology, University of Haifa, Mount Carmel, Haifa 31905, Israel
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA.
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32
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Dynamics of West Nile virus evolution in mosquito vectors. Curr Opin Virol 2016; 21:132-138. [PMID: 27788400 DOI: 10.1016/j.coviro.2016.09.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 01/24/2023]
Abstract
West Nile virus remains the most common cause of arboviral encephalitis in North America. Since it was introduced, it has undergone adaptive genetic change as it spread throughout the continent. The WNV transmission cycle is relatively tractable in the laboratory. Thus the virus serves as a convenient model system for studying the population biology of mosquito-borne flaviviruses as they undergo transmission to and from mosquitoes and vertebrates. This review summarizes the current knowledge regarding the population dynamics of this virus within mosquito vectors.
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33
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Grubaugh ND, Weger-Lucarelli J, Murrieta RA, Fauver JR, Garcia-Luna SM, Prasad AN, Black WC, Ebel GD. Genetic Drift during Systemic Arbovirus Infection of Mosquito Vectors Leads to Decreased Relative Fitness during Host Switching. Cell Host Microbe 2016; 19:481-92. [PMID: 27049584 DOI: 10.1016/j.chom.2016.03.002] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/19/2016] [Accepted: 03/07/2016] [Indexed: 11/30/2022]
Abstract
The emergence of mosquito-borne RNA viruses, such as West Nile virus (WNV), is facilitated by genetically complex virus populations within hosts. Here, we determine whether WNV enzootic (Culex tarsalis, Cx. quinquefasciatus, and Cx. pipiens) and bridge vectors (Aedes aegypti) have differential impacts on viral mutational diversity and fitness. During systemic mosquito infection, WNV faced stochastic reductions in genetic diversity that rapidly was recovered during intra-tissue population expansions. Interestingly, this intrahost selection and diversification was mosquito species dependent with Cx. tarsalis and Cx. quinquefasciatus exhibiting greater WNV divergence. However, recovered viral populations contained a preponderance of potentially deleterious mutations (i.e., high mutational load) and had lower relative fitness in avian cells compared to input virus. These findings demonstrate that the adaptive potential associated with mosquito transmission varies depending on the mosquito species and carries a significant fitness cost in vertebrates.
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Affiliation(s)
- Nathan D Grubaugh
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - James Weger-Lucarelli
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Reyes A Murrieta
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Joseph R Fauver
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Selene M Garcia-Luna
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Abhishek N Prasad
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - William C Black
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Gregory D Ebel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
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Abstract
Despite having very limited coding capacity, RNA viruses are able to withstand challenge of antiviral drugs, cause epidemics in previously exposed human populations, and, in some cases, infect multiple host species. They are able to achieve this by virtue of their ability to multiply very rapidly, coupled with their extraordinary degree of genetic heterogeneity. RNA viruses exist not as single genotypes, but as a swarm of related variants, and this genomic diversity is an essential feature of their biology. RNA viruses have a variety of mechanisms that act in combination to determine their genetic heterogeneity. These include polymerase fidelity, error-mitigation mechanisms, genomic recombination, and different modes of genome replication. RNA viruses can vary in their ability to tolerate mutations, or “genetic robustness,” and several factors contribute to this. Finally, there is evidence that some RNA viruses exist close to a threshold where polymerase error rate has evolved to maximize the possible sequence space available, while avoiding the accumulation of a lethal load of deleterious mutations. We speculate that different viruses have evolved different error rates to complement the different “life-styles” they possess.
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Affiliation(s)
- J.N. Barr
- University of Leeds, Leeds, United Kingdom
| | - R. Fearns
- Boston University School of Medicine, Boston, MA, United States
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35
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Abstract
Viral infection is a highly dynamic process, which lead to constant evolutionary changes on both sides of the viral–host interface. The high mutation rates of viruses, coupled with short generation times and large population sizes, allow viruses to rapidly adapt to the host environment. However, this high mutation rate also comes at a cost to the viral population, as deleterious mutations are constantly created, leading to a plethora of defective genomes. Here, we will discuss the basic tenets that govern the evolution of viruses: mutation rates, population size, selection, the multiplicity of infection, and how these factors modulate infection as viruses evolve within a host, during transmission to novel susceptible hosts, and as viruses establish infections in new host species.
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36
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Jones BA, Lessler J, Bianco S, Kaufman JH. Statistical Mechanics and Thermodynamics of Viral Evolution. PLoS One 2015; 10:e0137482. [PMID: 26422205 PMCID: PMC4589373 DOI: 10.1371/journal.pone.0137482] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 08/16/2015] [Indexed: 11/18/2022] Open
Abstract
This paper uses methods drawn from physics to study the life cycle of viruses. The paper analyzes a model of viral infection and evolution using the "grand canonical ensemble" and formalisms from statistical mechanics and thermodynamics. Using this approach we enumerate all possible genetic states of a model virus and host as a function of two independent pressures-immune response and system temperature. We prove the system has a real thermodynamic temperature, and discover a new phase transition between a positive temperature regime of normal replication and a negative temperature "disordered" phase of the virus. We distinguish this from previous observations of a phase transition that arises as a function of mutation rate. From an evolutionary biology point of view, at steady state the viruses naturally evolve to distinct quasispecies. This paper also reveals a universal relationship that relates the order parameter (as a measure of mutational robustness) to evolvability in agreement with recent experimental and theoretical work. Given that real viruses have finite length RNA segments that encode proteins which determine virus fitness, the approach used here could be refined to apply to real biological systems, perhaps providing insight into immune escape, the emergence of novel pathogens and other results of viral evolution.
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Affiliation(s)
- Barbara A. Jones
- Almaden Research Center, IBM, San Jose, California, United States of America
| | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Simone Bianco
- Almaden Research Center, IBM, San Jose, California, United States of America
| | - James H. Kaufman
- Almaden Research Center, IBM, San Jose, California, United States of America
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37
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Peck KM, Burch CL, Heise MT, Baric RS. Coronavirus Host Range Expansion and Middle East Respiratory Syndrome Coronavirus Emergence: Biochemical Mechanisms and Evolutionary Perspectives. Annu Rev Virol 2015; 2:95-117. [PMID: 26958908 DOI: 10.1146/annurev-virology-100114-055029] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Coronaviruses have frequently expanded their host range in recent history, with two events resulting in severe disease outbreaks in human populations. Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2003 in Southeast Asia and rapidly spread around the world before it was controlled by public health intervention strategies. The 2012 Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak represents another prime example of virus emergence from a zoonotic reservoir. Here, we review the current knowledge of coronavirus cross-species transmission, with particular focus on MERS-CoV. MERS-CoV is still circulating in the human population, and the mechanisms governing its cross-species transmission have been only partially elucidated, highlighting a need for further investigation. We discuss biochemical determinants mediating MERS-CoV host cell permissivity, including virus spike interactions with the MERS-CoV cell surface receptor dipeptidyl peptidase 4 (DPP4), and evolutionary mechanisms that may facilitate host range expansion, including recombination, mutator alleles, and mutational robustness. Understanding these mechanisms can help us better recognize the threat of emergence for currently circulating zoonotic strains.
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Affiliation(s)
| | | | - Mark T Heise
- Genetics.,Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina 27599;
| | - Ralph S Baric
- Epidemiology, and.,Microbiology and Immunology, University of North Carolina, Chapel Hill, North Carolina 27599;
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38
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Grubaugh ND, Smith DR, Brackney DE, Bosco-Lauth AM, Fauver JR, Campbell CL, Felix TA, Romo H, Duggal NK, Dietrich EA, Eike T, Beane JE, Bowen RA, Black WC, Brault AC, Ebel GD. Experimental evolution of an RNA virus in wild birds: evidence for host-dependent impacts on population structure and competitive fitness. PLoS Pathog 2015; 11:e1004874. [PMID: 25993022 PMCID: PMC4439088 DOI: 10.1371/journal.ppat.1004874] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/12/2015] [Indexed: 01/13/2023] Open
Abstract
Within hosts, RNA viruses form populations that are genetically and phenotypically complex. Heterogeneity in RNA virus genomes arises due to error-prone replication and is reduced by stochastic and selective mechanisms that are incompletely understood. Defining how natural selection shapes RNA virus populations is critical because it can inform treatment paradigms and enhance control efforts. We allowed West Nile virus (WNV) to replicate in wild-caught American crows, house sparrows and American robins to assess how natural selection shapes RNA virus populations in ecologically relevant hosts that differ in susceptibility to virus-induced mortality. After five sequential passages in each bird species, we examined the phenotype and population diversity of WNV through fitness competition assays and next generation sequencing. We demonstrate that fitness gains occur in a species-specific manner, with the greatest replicative fitness gains in robin-passaged WNV and the least in WNV passaged in crows. Sequencing data revealed that intrahost WNV populations were strongly influenced by purifying selection and the overall complexity of the viral populations was similar among passaged hosts. However, the selective pressures that control WNV populations seem to be bird species-dependent. Specifically, crow-passaged WNV populations contained the most unique mutations (~1.7× more than sparrows, ~3.4× more than robins) and defective genomes (~1.4× greater than sparrows, ~2.7× greater than robins), but the lowest average mutation frequency (about equal to sparrows, ~2.6× lower than robins). Therefore, our data suggest that WNV replication in the most disease-susceptible bird species is positively associated with virus mutational tolerance, likely via complementation, and negatively associated with the strength of selection. These differences in genetic composition most likely have distinct phenotypic consequences for the virus populations. Taken together, these results reveal important insights into how different hosts may contribute to the emergence of RNA viruses.
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Affiliation(s)
- Nathan D. Grubaugh
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Darci R. Smith
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Doug E. Brackney
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Angela M. Bosco-Lauth
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Joseph R. Fauver
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Corey L. Campbell
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Todd A. Felix
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Lakewood, Colorado, United States of America
| | - Hannah Romo
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Nisha K. Duggal
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Elizabeth A. Dietrich
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Tyler Eike
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Jennifer E. Beane
- Section for Computational Biomedicine, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Richard A. Bowen
- Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - William C. Black
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Aaron C. Brault
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, United States of America
| | - Gregory D. Ebel
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
- * E-mail:
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39
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Bank C, Hietpas RT, Jensen JD, Bolon DNA. A systematic survey of an intragenic epistatic landscape. Mol Biol Evol 2014; 32:229-38. [PMID: 25371431 DOI: 10.1093/molbev/msu301] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mutations are the source of evolutionary variation. The interactions of multiple mutations can have important effects on fitness and evolutionary trajectories. We have recently described the distribution of fitness effects of all single mutations for a nine-amino-acid region of yeast Hsp90 (Hsp82) implicated in substrate binding. Here, we report and discuss the distribution of intragenic epistatic effects within this region in seven Hsp90 point mutant backgrounds of neutral to slightly deleterious effect, resulting in an analysis of more than 1,000 double mutants. We find negative epistasis between substitutions to be common, and positive epistasis to be rare--resulting in a pattern that indicates a drastic change in the distribution of fitness effects one step away from the wild type. This can be well explained by a concave relationship between phenotype and genotype (i.e., a concave shape of the local fitness landscape), suggesting mutational robustness intrinsic to the local sequence space. Structural analyses indicate that, in this region, epistatic effects are most pronounced when a solvent-inaccessible position is involved in the interaction. In contrast, all 18 observations of positive epistasis involved at least one mutation at a solvent-exposed position. By combining the analysis of evolutionary and biophysical properties of an epistatic landscape, these results contribute to a more detailed understanding of the complexity of protein evolution.
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Affiliation(s)
- Claudia Bank
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Ryan T Hietpas
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
| | - Jeffrey D Jensen
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Daniel N A Bolon
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA
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