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Persistent Enterovirus Infection: Little Deletions, Long Infections. Vaccines (Basel) 2022; 10:vaccines10050770. [PMID: 35632526 PMCID: PMC9143164 DOI: 10.3390/vaccines10050770] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/04/2022] [Accepted: 05/10/2022] [Indexed: 01/27/2023] Open
Abstract
Enteroviruses have now been shown to persist in cell cultures and in vivo by a novel mechanism involving the deletion of varying amounts of the 5′ terminal genomic region termed domain I (also known as the cloverleaf). Molecular clones of coxsackievirus B3 (CVB3) genomes with 5′ terminal deletions (TD) of varying length allow the study of these mutant populations, which are able to replicate in the complete absence of wildtype virus genomes. The study of TD enteroviruses has revealed numerous significant differences from canonical enteroviral biology. The deletions appear and become the dominant population when an enterovirus replicates in quiescent cell populations, but can also occur if one of the cis-acting replication elements of the genome (CRE-2C) is artificially mutated in the element’s stem and loop structures. This review discusses how the TD genomes arise, how they interact with the host, and their effects on host biology.
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2
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Ravn Warncke S, Rohde Knudsen C. Detection methods targeting the positive- and negative-sense RNA transcripts from plus-stranded RNA viruses. APMIS 2021; 130:284-292. [PMID: 34939239 PMCID: PMC9306919 DOI: 10.1111/apm.13202] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 12/16/2021] [Indexed: 11/27/2022]
Abstract
The largest group of viruses in the Baltimore classification system comprises viruses with a positive-sense, single-stranded RNA genome. Once the viral genome is released into the cytoplasm of a specific host cell following virus entry, it functions directly as a mRNA and the virus-encoded proteins that are essential for genome replication, are produced by the translation apparatus of the host cell. The positive-sense genome is replicated in two stages, initially the positive strand is copied to make a negative-sense RNA, which then functions as the template for transcription of many new positive-sense genomes. Virus infections can be detected at different stages throughout the infection cycle for diagnostic and scientific purposes. Here, the advantages and disadvantages of some of the relevant methods for genome detection will be briefly reviewed with special emphasis on techniques allowing strand-specific RNA detection. Furthermore, tools of the future are considered.
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Affiliation(s)
- Signe Ravn Warncke
- Department of Molecular Biology & Genetics, University of Aarhus, Gustav Wieds Vej 10 C, DK-8000, Aarhus C, Denmark
| | - Charlotte Rohde Knudsen
- Department of Molecular Biology & Genetics, University of Aarhus, Gustav Wieds Vej 10 C, DK-8000, Aarhus C, Denmark
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3
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High-Order Epistasis and Functional Coupling of Infection Steps Drive Virus Evolution toward Independence from a Host Pathway. Microbiol Spectr 2021; 9:e0080021. [PMID: 34468191 PMCID: PMC8557862 DOI: 10.1128/spectrum.00800-21] [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] [Indexed: 12/24/2022] Open
Abstract
The phosphatidylinositol-4 kinase IIIβ (PI4KB)/oxysterol-binding protein (OSBP) family I pathway serves as an essential host pathway for the formation of viral replication complex for viral plus-strand RNA synthesis; however, poliovirus (PV) could evolve toward substantial independence from this host pathway with four mutations. Recessive epistasis of the two mutations (3A-R54W and 2B-F17L) is essential for viral RNA replication. Quantitative analysis of effects of the other two mutations (2B-Q20H and 2C-M187V) on each step of infection reveals functional couplings between viral replication, growth, and spread conferred by the 2B-Q20H mutation, while no enhancing effect was conferred by the 2C-M187V mutation. The effects of the 2B-Q20H mutation occur only via another recessive epistasis between the 3A-R54W/2B-F17L mutations. These mutations confer enhanced replication in PI4KB/OSBP-independent infection concomitantly with an increased ratio of viral plus-strand RNA to the minus-strand RNA. This work reveals the essential roles of the functional coupling and high-order, multi-tiered recessive epistasis in viral evolution toward independence from an obligatory host pathway. IMPORTANCE Each virus has a different strategy for its replication, which requires different host factors. Enterovirus, a model RNA virus, requires host factors PI4KB and OSBP, which form an obligatory functional axis to support viral replication. In an experimental evolution system in vitro, virus mutants that do not depend on these host factors could arise only with four mutations. The two mutations (3A-R54W and 2B-F17L) are required for the replication but are not sufficient to support efficient infection. Another mutation (2B-Q20H) is essential for efficient spread of the virus. The order of introduction of the mutations in the viral genome is essential (known as “epistasis”), and functional couplings of infection steps (i.e., viral replication, growth, and spread) have substantial roles to show the effects of the 2B-Q20H mutation. These observations would provide novel insights into an evolutionary pathway of the virus to require host factors for infection.
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4
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Nigg JC, Mongelli V, Blanc H, Saleh MC. Innovative Toolbox for the Quantification of Drosophila C Virus, Drosophila A Virus, and Nora Virus. J Mol Biol 2021; 434:167308. [PMID: 34678301 DOI: 10.1016/j.jmb.2021.167308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/28/2021] [Accepted: 10/12/2021] [Indexed: 11/29/2022]
Abstract
Quantification of viral replication underlies investigations into host-virus interactions. In Drosophila melanogaster, persistent infections with Drosophila C virus, Drosophila A virus, and Nora virus are commonly observed in nature and in laboratory fly stocks. However, traditional endpoint dilution assays to quantify infectious titers are not compatible with persistently infecting isolates of these viruses that do not cause cytopathic effects in cell culture. Here we present a novel assay based on immunological detection of Drosophila C virus infection that allows quantification of infectious titers for a wider range of Drosophila C virus isolates. We also describe strand specific RT-qPCR assays for quantification of viral negative strand RNA produced during Drosophila C virus, Drosophila A virus, and Nora virus infection. Finally, we demonstrate the utility of these assays for quantification of viral replication during oral infections and persistent infections with each virus.
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Affiliation(s)
- Jared C Nigg
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS UMR 3569, 75724 Paris CEDEX 15, France.
| | - Vanesa Mongelli
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS UMR 3569, 75724 Paris CEDEX 15, France.
| | - Hervé Blanc
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS UMR 3569, 75724 Paris CEDEX 15, France.
| | - Maria-Carla Saleh
- Viruses and RNA Interference Unit, Institut Pasteur, CNRS UMR 3569, 75724 Paris CEDEX 15, France.
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5
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Zhang M, Li K, Bai J, Velema WA, Yu C, van Damme R, Lee WH, Corpuz ML, Chen JF, Lu Z. Optimized photochemistry enables efficient analysis of dynamic RNA structuromes and interactomes in genetic and infectious diseases. Nat Commun 2021; 12:2344. [PMID: 33879794 PMCID: PMC8058046 DOI: 10.1038/s41467-021-22552-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 03/18/2021] [Indexed: 02/02/2023] Open
Abstract
Direct determination of RNA structures and interactions in living cells is critical for understanding their functions in normal physiology and disease states. Here, we present PARIS2, a dramatically improved method for RNA duplex determination in vivo with >4000-fold higher efficiency than previous methods. PARIS2 captures ribosome binding sites on mRNAs, reporting translation status on a transcriptome scale. Applying PARIS2 to the U8 snoRNA mutated in the neurological disorder LCC, we discover a network of dynamic RNA structures and interactions which are destabilized by patient mutations. We report the first whole genome structure of enterovirus D68, an RNA virus that causes polio-like symptoms, revealing highly dynamic conformations altered by antiviral drugs and different pathogenic strains. We also discover a replication-associated asymmetry on the (+) and (-) strands of the viral genome. This study establishes a powerful technology for efficient interrogation of the RNA structurome and interactome in human diseases.
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MESH Headings
- Calcinosis/genetics
- Calcinosis/metabolism
- Central Nervous System Cysts/genetics
- Central Nervous System Cysts/metabolism
- Communicable Diseases/genetics
- Communicable Diseases/metabolism
- Cross-Linking Reagents
- Enterovirus D, Human/genetics
- Furocoumarins
- Genetic Diseases, Inborn/genetics
- Genetic Diseases, Inborn/metabolism
- Genome, Viral
- Humans
- Leukoencephalopathies/genetics
- Leukoencephalopathies/metabolism
- Models, Molecular
- Mutation
- Nucleic Acid Conformation
- Photochemical Processes
- Photochemistry/methods
- RNA/chemistry
- RNA/genetics
- RNA/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Small Nucleolar/chemistry
- RNA, Small Nucleolar/genetics
- RNA, Small Nucleolar/metabolism
- RNA, Viral/chemistry
- RNA, Viral/genetics
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Affiliation(s)
- Minjie Zhang
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Kongpan Li
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Jianhui Bai
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Willem A Velema
- Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Chengqing Yu
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Ryan van Damme
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Wilson H Lee
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Maia L Corpuz
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA
| | - Jian-Fu Chen
- Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA, USA
| | - Zhipeng Lu
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA, USA.
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6
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Modeling the complete kinetics of coxsackievirus B3 reveals human determinants of host-cell feedback. Cell Syst 2021; 12:304-323.e13. [PMID: 33740397 DOI: 10.1016/j.cels.2021.02.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 01/13/2021] [Accepted: 02/19/2021] [Indexed: 12/13/2022]
Abstract
Complete kinetic models are pervasive in chemistry but lacking in biological systems. We encoded the complete kinetics of infection for coxsackievirus B3 (CVB3), a compact and fast-acting RNA virus. The model consists of separable, detailed modules describing viral binding-delivery, translation-replication, and encapsidation. Specific module activities are dampened by the type I interferon response to viral double-stranded RNAs (dsRNAs), which is itself disrupted by viral proteinases. The experimentally validated kinetics uncovered that cleavability of the dsRNA transducer mitochondrial antiviral signaling protein (MAVS) becomes a stronger determinant of viral outcomes when cells receive supplemental interferon after infection. Cleavability is naturally altered in humans by a common MAVS polymorphism, which removes a proteinase-targeted site but paradoxically elevates CVB3 infectivity. These observations are reconciled with a simple nonlinear model of MAVS regulation. Modeling complete kinetics is an attainable goal for small, rapidly infecting viruses and perhaps viral pathogens more broadly. A record of this paper's transparent peer review process is included in the Supplemental information.
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7
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Specific Assay of Negative Strand Template to Quantify Intracellular Levels of Rhinovirus Double-Stranded RNA. Methods Protoc 2021; 4:mps4010013. [PMID: 33670292 PMCID: PMC8006032 DOI: 10.3390/mps4010013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/05/2021] [Accepted: 02/09/2021] [Indexed: 11/16/2022] Open
Abstract
Human rhinovirus infections are a major trigger for acute exacerbations of lower airway diseases, including asthma and chronic obstructive pulmonary disease. Disease exacerbation is thought to be regulated via double-stranded RNA (dsRNA)-mediated signaling of proinflammatory and host defense responses in airway epithelial cells. Despite the central role of dsRNA in regulating host cell responses, no method for the quantitative assessment of dsRNA levels during HRV infections has been developed. Conventional RT-PCR for the negative strand template is not effective as self-priming results in apparent signals, even in the absence of primer during reverse transcription. To avoid these issues, we developed a selective assay for the negative strand template that uses a chimeric primer containing a 5′ non-viral sequence for reverse transcription and a primer using the non-viral sequence during subsequent PCR. We established that this assay avoided issues of self-priming and is strand specific, as it is unaffected even in the presence of a 1000-fold excess of positive strand. Assays in primary human airway epithelial cells showed that negative strand was detectable within 6 h of virus exposure and peaked at 18 h after virus exposure. The temporal pattern of negative strand induction mirrored that of genomic RNA but was always 1000-fold lower than positive strand, indicating that the negative strand levels regulate levels of dsRNA formation. This assay will permit relative quantification of dsRNA during studies of HRV regulation of epithelial cell function.
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8
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Salmikangas S, Laiho JE, Kalander K, Laajala M, Honkimaa A, Shanina I, Oikarinen S, Horwitz MS, Hyöty H, Marjomäki V. Detection of Viral -RNA and +RNA Strands in Enterovirus-Infected Cells and Tissues. Microorganisms 2020; 8:microorganisms8121928. [PMID: 33291747 PMCID: PMC7761939 DOI: 10.3390/microorganisms8121928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/24/2020] [Accepted: 12/02/2020] [Indexed: 11/16/2022] Open
Abstract
The current methods to study the distribution and dynamics of viral RNA molecules inside infected cells are not ideal, as electron microscopy and immunohistochemistry can only detect mature virions, and quantitative real-time PCR does not reveal localized distribution of RNAs. We demonstrated here the branched DNA in situ hybridization (bDNA ISH) technology to study both the amount and location of the emerging -RNA and +RNA during acute and persistent enterovirus infections. According to our results, the replication of the viral RNA started 2-3 h after infection and the translation shortly after at 3-4 h post-infection. The replication hotspots with newly emerging -RNA were located quite centrally in the cell, while the +RNA production and most likely virion assembly took place in the periphery of the cell. We also discovered that the pace of replication of -RNA and +RNA strands was almost identical, and -RNA was absent during antiviral treatments. ViewRNA ISH with our custom probes also showed a good signal during acute and persistent enterovirus infections in cell and mouse models. Considering these results, along with the established bDNA FISH protocol modified by us, the effects of antiviral drugs and the emergence of enterovirus RNAs in general can be studied more effectively.
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Affiliation(s)
- Sami Salmikangas
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Survontie 9C, FI-40500 Jyväskylä, Finland; (S.S.); (K.K.); (M.L.)
| | - Jutta E. Laiho
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland; (J.E.L.); (A.H.); (S.O.); (H.H.)
| | - Kerttu Kalander
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Survontie 9C, FI-40500 Jyväskylä, Finland; (S.S.); (K.K.); (M.L.)
| | - Mira Laajala
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Survontie 9C, FI-40500 Jyväskylä, Finland; (S.S.); (K.K.); (M.L.)
| | - Anni Honkimaa
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland; (J.E.L.); (A.H.); (S.O.); (H.H.)
| | - Iryna Shanina
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada; (I.S.); (M.S.H.)
| | - Sami Oikarinen
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland; (J.E.L.); (A.H.); (S.O.); (H.H.)
| | - Marc S. Horwitz
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia, Vancouver, BC V6T1Z3, Canada; (I.S.); (M.S.H.)
| | - Heikki Hyöty
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland; (J.E.L.); (A.H.); (S.O.); (H.H.)
| | - Varpu Marjomäki
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Survontie 9C, FI-40500 Jyväskylä, Finland; (S.S.); (K.K.); (M.L.)
- Correspondence: ; Tel.: +358-405634422
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9
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Yang JE, Rossignol ED, Chang D, Zaia J, Forrester I, Raja K, Winbigler H, Nicastro D, Jackson WT, Bullitt E. Complexity and ultrastructure of infectious extracellular vesicles from cells infected by non-enveloped virus. Sci Rep 2020; 10:7939. [PMID: 32409751 PMCID: PMC7224179 DOI: 10.1038/s41598-020-64531-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 04/15/2020] [Indexed: 02/07/2023] Open
Abstract
Enteroviruses support cell-to-cell viral transmission prior to their canonical lytic spread of virus. Poliovirus (PV), a prototype for human pathogenic positive-sense RNA enteroviruses, and picornaviruses in general, transport multiple virions en bloc via infectious extracellular vesicles, 100~1000 nm in diameter, secreted from host cells. Using biochemical and biophysical methods we identify multiple components in secreted microvesicles, including mature PV virions; positive-sense genomic and negative-sense replicative, template viral RNA; essential viral replication proteins; and cellular proteins. Using cryo-electron tomography, we visualize the near-native three-dimensional architecture of secreted infectious microvesicles containing both virions and a unique morphological component that we describe as a mat-like structure. While the composition of these mat-like structures is not yet known, based on our biochemical data they are expected to be comprised of unencapsidated RNA and proteins. In addition to infectious microvesicles, CD9-positive exosomes released from PV-infected cells are also infectious and transport virions. Thus, our data show that, prior to cell lysis, non-enveloped viruses are secreted within infectious vesicles that also transport viral unencapsidated RNAs, viral and host proteins. Understanding the structure and function of these infectious particles helps elucidate the mechanism by which extracellular vesicles contribute to the spread of non-enveloped virus infection.
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Affiliation(s)
- Jie E Yang
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.,Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, United States
| | - Evan D Rossignol
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA, 02139, United States
| | - Deborah Chang
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, United States
| | - Joseph Zaia
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, 02118, United States
| | - Isaac Forrester
- Department of Biochemistry, Baylor College of Medicine, Houston, United States
| | - Kiran Raja
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.,Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, 19104, United States
| | - Holly Winbigler
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 20201, United States
| | - Daniela Nicastro
- Departments of Cell Biology and Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75235, United States
| | - William T Jackson
- Department of Microbiology & Immunology, University of Maryland School of Medicine, Baltimore, MD, 20201, United States
| | - Esther Bullitt
- Department of Physiology & Biophysics, Boston University School of Medicine, Boston, MA, 02118, United States.
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10
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Bouin A, Gretteau PA, Wehbe M, Renois F, N'Guyen Y, Lévêque N, Vu MN, Tracy S, Chapman NM, Bruneval P, Fornes P, Semler BL, Andreoletti L. Enterovirus Persistence in Cardiac Cells of Patients With Idiopathic Dilated Cardiomyopathy Is Linked to 5' Terminal Genomic RNA-Deleted Viral Populations With Viral-Encoded Proteinase Activities. Circulation 2020; 139:2326-2338. [PMID: 30755025 DOI: 10.1161/circulationaha.118.035966] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Group B enteroviruses are common causes of acute myocarditis, which can be a precursor of chronic myocarditis and dilated cardiomyopathy, leading causes of heart transplantation. To date, the specific viral functions involved in the development of dilated cardiomyopathy remain unclear. METHODS Total RNA from cardiac tissue of patients with dilated cardiomyopathy was extracted, and sequences corresponding to the 5' termini of enterovirus RNAs were identified. After next-generation RNA sequencing, viral cDNA clones mimicking the enterovirus RNA sequences found in patient tissues were generated in vitro, and their replication and impact on host cell functions were assessed on primary human cardiac cells in culture. RESULTS Major enterovirus B populations characterized by 5' terminal genomic RNA deletions ranging from 17 to 50 nucleotides were identified either alone or associated with low proportions of intact 5' genomic termini. In situ hybridization and immunohistological assays detected these persistent genomes in clusters of cardiomyocytes. Transfection of viral RNA into primary human cardiomyocytes demonstrated that deleted forms of genomic RNAs displayed early replication activities in the absence of detectable viral plaque formation, whereas mixed deleted and complete forms generated particles capable of inducing cytopathic effects at levels distinct from those observed with full-length forms alone. Moreover, deleted or full-length and mixed forms of viral RNA were capable of directing translation and production of proteolytically active viral proteinase 2A in human cardiomyocytes. CONCLUSIONS We demonstrate that persistent viral forms are composed of B-type enteroviruses harboring a 5' terminal deletion in their genomic RNAs and that these viruses alone or associated with full-length populations of helper RNAs could impair cardiomyocyte functions by the proteolytic activity of viral proteinase 2A in cases of unexplained dilated cardiomyopathy. These results provide a better understanding of the molecular mechanisms that underlie the persistence of EV forms in human cardiac tissues and should stimulate the development of new therapeutic strategies based on specific inhibitors of the coxsackievirus B proteinase 2A activity for acute and chronic cardiac infections.
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Affiliation(s)
- Alexis Bouin
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.).,Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine (A.B., M.N.V., B.L.S.)
| | - Paul-Antoine Gretteau
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.)
| | - Michel Wehbe
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.).,Centre AZM pour la recherche en biotechnologie et ses applications, Université Libanaise, Tripoli, Lebanon (M.W.)
| | - Fanny Renois
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.).,LUNAM University, Oniris, LABERCA, UMR INRA 1329, Nantes, France (F.R.).,CHU Robert Debré, Laboratoire de Virologie Médicale et Moléculaire, Reims, France (F.R., Y.N., N.L., P.F., L.A.)
| | - Yohan N'Guyen
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.).,CHU Robert Debré, Laboratoire de Virologie Médicale et Moléculaire, Reims, France (F.R., Y.N., N.L., P.F., L.A.)
| | - Nicolas Lévêque
- CHU Robert Debré, Laboratoire de Virologie Médicale et Moléculaire, Reims, France (F.R., Y.N., N.L., P.F., L.A.).,EA-4331 LITEC, Faculty of Medicine and Pharmacy, University Hospital of Poitiers, France (N.L.)
| | - Michelle N Vu
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine (A.B., M.N.V., B.L.S.)
| | - Steven Tracy
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha (S.T., N.M.C.)
| | - Nora M Chapman
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha (S.T., N.M.C.)
| | - Patrick Bruneval
- Service d'Anatomie Pathologique, Hôpital Européen Georges Pompidou, Paris, France (P.B.)
| | - Paul Fornes
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.)
| | - Bert L Semler
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine (A.B., M.N.V., B.L.S.)
| | - Laurent Andreoletti
- EA-4684 Cardiovir, Faculty of Medicine, University of Reims Champagne-Ardenne, Reims, France (A.B., P.-A.G., M.W., F.R., Y.N., A.R., P.F., L.A.)
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11
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Dinan AM, Lukhovitskaya NI, Olendraite I, Firth AE. A case for a negative-strand coding sequence in a group of positive-sense RNA viruses. Virus Evol 2020; 6:veaa007. [PMID: 32064120 PMCID: PMC7010960 DOI: 10.1093/ve/veaa007] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Positive-sense single-stranded RNA viruses form the largest and most diverse group of eukaryote-infecting viruses. Their genomes comprise one or more segments of coding-sense RNA that function directly as messenger RNAs upon release into the cytoplasm of infected cells. Positive-sense RNA viruses are generally accepted to encode proteins solely on the positive strand. However, we previously identified a surprisingly long (∼1,000-codon) open reading frame (ORF) on the negative strand of some members of the family Narnaviridae which, together with RNA bacteriophages of the family Leviviridae, form a sister group to all other positive-sense RNA viruses. Here, we completed the genomes of three mosquito-associated narnaviruses, all of which have the long reverse-frame ORF. We systematically identified narnaviral sequences in public data sets from a wide range of sources, including arthropod, fungal, and plant transcriptomic data sets. Long reverse-frame ORFs are widespread in one clade of narnaviruses, where they frequently occupy >95 per cent of the genome. The reverse-frame ORFs correspond to a specific avoidance of CUA, UUA, and UCA codons (i.e. stop codon reverse complements) in the forward-frame RNA-dependent RNA polymerase ORF. However, absence of these codons cannot be explained by other factors such as inability to decode these codons or GC3 bias. Together with other analyses, we provide the strongest evidence yet of coding capacity on the negative strand of a positive-sense RNA virus. As these ORFs comprise some of the longest known overlapping genes, their study may be of broad relevance to understanding overlapping gene evolution and de novo origin of genes.
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Affiliation(s)
- Adam M Dinan
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Nina I Lukhovitskaya
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Ingrida Olendraite
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Andrew E Firth
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
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12
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Visualization of Positive and Negative Sense Viral RNA for Probing the Mechanism of Direct-Acting Antivirals against Hepatitis C Virus. Viruses 2019; 11:v11111039. [PMID: 31717338 PMCID: PMC6893808 DOI: 10.3390/v11111039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/03/2019] [Accepted: 11/07/2019] [Indexed: 12/14/2022] Open
Abstract
RNA viruses are highly successful pathogens and are the causative agents for many important diseases. To fully understand the replication of these viruses it is necessary to address the roles of both positive-strand RNA ((+)RNA) and negative-strand RNA ((−)RNA), and their interplay with viral and host proteins. Here we used branched DNA (bDNA) fluorescence in situ hybridization (FISH) to stain both the abundant (+)RNA and the far less abundant (−)RNA in both hepatitis C virus (HCV)- and Zika virus-infected cells, and combined these analyses with visualization of viral proteins through confocal imaging. We were able to phenotypically examine HCV-infected cells in the presence of uninfected cells and revealed the effect of direct-acting antivirals on HCV (+)RNA, (−)RNA, and protein, within hours of commencing treatment. Herein, we demonstrate that bDNA FISH is a powerful tool for the study of RNA viruses that can provide insights into drug efficacy and mechanism of action.
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13
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Pryshliak M, Hazini A, Knoch K, Dieringer B, Tolksdorf B, Solimena M, Kurreck J, Pinkert S, Fechner H. MiR‐375‐mediated suppression of engineered coxsackievirus B3 in pancreatic cells. FEBS Lett 2019; 594:763-775. [DOI: 10.1002/1873-3468.13647] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/02/2019] [Accepted: 10/15/2019] [Indexed: 01/07/2023]
Affiliation(s)
- Markian Pryshliak
- Department of Applied Biochemistry Institute of Biotechnology Technische Universität Berlin Germany
| | - Ahmet Hazini
- Department of Applied Biochemistry Institute of Biotechnology Technische Universität Berlin Germany
| | - Klaus Knoch
- Paul Langerhans Institute Dresden Helmholtz Center Munich Faculty of Medicine University Hospital Carl Gustav Carus Technische Universität Dresden Germany
| | - Babette Dieringer
- Department of Applied Biochemistry Institute of Biotechnology Technische Universität Berlin Germany
| | - Beatrice Tolksdorf
- Department of Applied Biochemistry Institute of Biotechnology Technische Universität Berlin Germany
| | - Michele Solimena
- Paul Langerhans Institute Dresden Helmholtz Center Munich Faculty of Medicine University Hospital Carl Gustav Carus Technische Universität Dresden Germany
| | - Jens Kurreck
- Department of Applied Biochemistry Institute of Biotechnology Technische Universität Berlin Germany
| | - Sandra Pinkert
- Corporate Member of Freie Universität Berlin Berlin Institute of Health (BIH) Institute of Biochemistry Charité ‐ Universitätsmedizin Berlin Humboldt‐Universität zu Berlin Germany
| | - Henry Fechner
- Department of Applied Biochemistry Institute of Biotechnology Technische Universität Berlin Germany
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14
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Warner SM, Wiehler S, Michi AN, Proud D. Rhinovirus replication and innate immunity in highly differentiated human airway epithelial cells. Respir Res 2019; 20:150. [PMID: 31299975 PMCID: PMC6626354 DOI: 10.1186/s12931-019-1120-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/01/2019] [Indexed: 12/23/2022] Open
Abstract
Background Human rhinovirus (HRV) infections are the primary cause of the common cold and are a major trigger for exacerbations of lower airway diseases, such as asthma and chronic obstructive pulmonary diseases. Although human bronchial epithelial cells (HBE) are the natural host for HRV infections, much of our understanding of how HRV replicates and induces host antiviral responses is based on studies using non-airway cell lines (e.g. HeLa cells). The current study examines the replication cycle of HRV, and host cell responses, in highly differentiated cultures of HBE. Methods Highly differentiated cultures of HBE were exposed to initial infectious doses ranging from 104 to 101 50% tissue culture-infective dose (TCID50) of purified HRV-16, and responses were monitored up to 144 h after infection. Viral genomic RNA and negative strand RNA template levels were monitored, along with levels of type I and II interferons and selected antivirals. Results Regardless of initial infectious dose, relatively constant levels of both genomic and negative strand RNA are generated during replication, with negative strand copy numbers being10,000-fold lower than those of genomic strands. Infections were limited to a small percentage of ciliated cells and did not result in any overt signs of epithelial death. Importantly, regardless of infectious dose, HRV-16 infections were cleared by HBE in the absence of immune cells. Levels of type I and type III interferons (IFNs) varied with initial infectious dose, implying that factors other than levels of double-stranded RNA regulate IFN induction, but the time-course of HRV-16 clearance HBE was the same regardless of levels of IFNs produced. Patterns of antiviral viperin and ISG15 expression suggest they may be generated in an IFN-independent manner during HRV-16 infections. Conclusions These data challenge a number of aspects of dogma generated from studies in HeLa cells and emphasize the importance of appropriate cell context when studying HRV infections.
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Affiliation(s)
- Stephanie M Warner
- Department of Physiology & Pharmacology and Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Shahina Wiehler
- Department of Physiology & Pharmacology and Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - Aubrey N Michi
- Department of Physiology & Pharmacology and Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada
| | - David Proud
- Department of Physiology & Pharmacology and Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB, T2N 4Z6, Canada.
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15
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Dave P, George B, Balakrishnan S, Sharma DK, Raheja H, Dixit NM, Das S. Strand-specific affinity of host factor hnRNP C1/C2 guides positive to negative-strand ratio in Coxsackievirus B3 infection. RNA Biol 2019; 16:1286-1299. [PMID: 31234696 DOI: 10.1080/15476286.2019.1629208] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Coxsackievirus B3 is an enterovirus, with positive-sense single-stranded RNA genome containing 'Internal Ribosome Entry Site' (IRES) in the 5'UTR. Once sufficient viral proteins are synthesized in the cell from the input RNA, viral template switches from translation to replication to synthesize negative-strand RNA. Inhibition of translation is a key step in regulating this switch as the positive-strand RNA template should be free of ribosomes to enable polymerase movement. In this study, we show how a host protein hnRNP C1/C2 inhibits viral RNA translation. hnRNP C1/C2 interacts with stem-loop V in the IRES and displaces poly-pyrimidine tract binding protein, a positive regulator of translation. We further demonstrate that hnRNP C1/C2 induces translation to replication switch, independently from the already known role of the ternary complex (PCBP2-3CD-cloverleaf RNA). These results suggest a novel function of hnRNP C1/C2 in template switching of positive-strand from translation to replication by a new mechanism. Using mathematical modelling, we show that the differential affinity of hnRNP C1/C2 for positive and negative-strand RNAs guides the final ± RNA ratio, providing first insight in the regulation of the positive to negative-strand RNA ratio in enteroviruses.
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Affiliation(s)
- Pratik Dave
- a Department of Microbiology and Cell Biology, Indian Institute of Science , Bangalore , Karnataka , India
| | - Biju George
- a Department of Microbiology and Cell Biology, Indian Institute of Science , Bangalore , Karnataka , India
| | - Sreenath Balakrishnan
- b Center for BioSystems Science and Engineering, Indian Institute of Science , Bangalore , Karnataka , India
| | - Divya Khandige Sharma
- a Department of Microbiology and Cell Biology, Indian Institute of Science , Bangalore , Karnataka , India
| | - Harsha Raheja
- a Department of Microbiology and Cell Biology, Indian Institute of Science , Bangalore , Karnataka , India
| | - Narendra M Dixit
- b Center for BioSystems Science and Engineering, Indian Institute of Science , Bangalore , Karnataka , India.,c Department of Chemical Engineering, Indian Institute of Science , Bangalore , Karnataka , India
| | - Saumitra Das
- a Department of Microbiology and Cell Biology, Indian Institute of Science , Bangalore , Karnataka , India.,b Center for BioSystems Science and Engineering, Indian Institute of Science , Bangalore , Karnataka , India.,d Centre for Infectious Disease Research, Indian Institute of Science , Bangalore , Karnataka , India.,e Infectious Disease Research, National Institute of Biomedical Genomics , Kalyani , West Bengal , India
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16
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Functional Consequences of RNA 5'-Terminal Deletions on Coxsackievirus B3 RNA Replication and Ribonucleoprotein Complex Formation. J Virol 2017; 91:JVI.00423-17. [PMID: 28539455 DOI: 10.1128/jvi.00423-17] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/17/2017] [Indexed: 12/11/2022] Open
Abstract
Group B coxsackieviruses are responsible for chronic cardiac infections. However, the molecular mechanisms by which the virus can persist in the human heart long after the signs of acute myocarditis have abated are still not completely understood. Recently, coxsackievirus B3 strains with 5'-terminal deletions in genomic RNAs were isolated from a patient suffering from idiopathic dilated cardiomyopathy, suggesting that such mutant viruses may be the forms responsible for persistent infection. These deletions lacked portions of 5' stem-loop I, which is an RNA secondary structure required for viral RNA replication. In this study, we assessed the consequences of the genomic deletions observed in vivo for coxsackievirus B3 biology. Using cell extracts from HeLa cells, as well as transfection of luciferase replicons in two types of cardiomyocytes, we demonstrated that coxsackievirus RNAs harboring 5' deletions ranging from 7 to 49 nucleotides in length can be translated nearly as efficiently as those of wild-type virus. However, these 5' deletions greatly reduced the synthesis of viral RNA in vitro, which was detected only for the 7- and 21-nucleotide deletions. Since 5' stem-loop I RNA forms a ribonucleoprotein complex with cellular and viral proteins involved in viral RNA replication, we investigated the binding of the host cell protein PCBP2, as well as viral protein 3CDpro, to deleted positive-strand RNAs corresponding to the 5' end. We found that binding of these proteins was conserved but that ribonucleoprotein complex formation required higher PCBP2 and 3CDpro concentrations, depending on the size of the deletion. Overall, this study confirmed the characteristics of persistent CVB3 infection observed in heart tissues and provided a possible explanation for the low level of RNA replication observed for the 5'-deleted viral genomes-a less stable ribonucleoprotein complex formed with proteins involved in viral RNA replication.IMPORTANCE Dilated cardiomyopathy is the most common indication for heart transplantation worldwide, and coxsackie B viruses are detected in about one-third of idiopathic dilated cardiomyopathies. Terminal deletions at the 5' end of the viral genome involving an RNA secondary structure required for RNA replication have been recently reported as a possible mechanism of virus persistence in the human heart. These mutations are likely to disrupt the correct folding of an RNA secondary structure required for viral RNA replication. In this report, we demonstrate that transfected RNAs harboring 5'-terminal sequence deletions are able to direct the synthesis of viral proteins, but not genomic RNAs, in human and murine cardiomyocytes. Moreover, we show that the binding of cellular and viral replication factors to viral RNA is conserved despite genomic deletions but that the impaired RNA synthesis associated with terminally deleted viruses could be due to destabilization of the ribonucleoprotein complexes formed.
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17
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Woodman A, Arnold JJ, Cameron CE, Evans DJ. Biochemical and genetic analysis of the role of the viral polymerase in enterovirus recombination. Nucleic Acids Res 2016; 44:6883-95. [PMID: 27317698 PMCID: PMC5001610 DOI: 10.1093/nar/gkw567] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 06/14/2016] [Indexed: 11/13/2022] Open
Abstract
Genetic recombination in single-strand, positive-sense RNA viruses is a poorly understand mechanism responsible for generating extensive genetic change and novel phenotypes. By moving a critical cis-acting replication element (CRE) from the polyprotein coding region to the 3′ non-coding region we have further developed a cell-based assay (the 3′CRE-REP assay) to yield recombinants throughout the non-structural coding region of poliovirus from dually transfected cells. We have additionally developed a defined biochemical assay in which the only protein present is the poliovirus RNA dependent RNA polymerase (RdRp), which recapitulates the strand transfer events of the recombination process. We have used both assays to investigate the role of the polymerase fidelity and nucleotide turnover rates in recombination. Our results, of both poliovirus intertypic and intratypic recombination in the CRE-REP assay and using a range of polymerase variants in the biochemical assay, demonstrate that RdRp fidelity is a fundamental determinant of recombination frequency. High fidelity polymerases exhibit reduced recombination and low fidelity polymerases exhibit increased recombination in both assays. These studies provide the basis for the analysis of poliovirus recombination throughout the non-structural region of the virus genome and provide a defined biochemical assay to further dissect this important evolutionary process.
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Affiliation(s)
- Andrew Woodman
- Dept. of Biochemistry & Molecular Biology, 201 Althouse Lab, University Park, PA 16802, USA
| | - Jamie J Arnold
- Dept. of Biochemistry & Molecular Biology, 201 Althouse Lab, University Park, PA 16802, USA
| | - Craig E Cameron
- Dept. of Biochemistry & Molecular Biology, 201 Althouse Lab, University Park, PA 16802, USA
| | - David J Evans
- Biomedical Sciences Research Complex, North Haugh, University of St. Andrews, St. Andrews KY16 9ST, UK
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18
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Laitinen OH, Svedin E, Kapell S, Nurminen A, Hytönen VP, Flodström-Tullberg M. Enteroviral proteases: structure, host interactions and pathogenicity. Rev Med Virol 2016; 26:251-67. [PMID: 27145174 PMCID: PMC7169145 DOI: 10.1002/rmv.1883] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 12/22/2022]
Abstract
Enteroviruses are common human pathogens, and infections are particularly frequent in children. Severe infections can lead to a variety of diseases, including poliomyelitis, aseptic meningitis, myocarditis and neonatal sepsis. Enterovirus infections have also been implicated in asthmatic exacerbations and type 1 diabetes. The large disease spectrum of the closely related enteroviruses may be partially, but not fully, explained by differences in tissue tropism. The molecular mechanisms by which enteroviruses cause disease are poorly understood, but there is increasing evidence that the two enteroviral proteases, 2Apro and 3Cpro, are important mediators of pathology. These proteases perform the post‐translational proteolytic processing of the viral polyprotein, but they also cleave several host‐cell proteins in order to promote the production of new virus particles, as well as to evade the cellular antiviral immune responses. Enterovirus‐associated processing of cellular proteins may also contribute to pathology, as elegantly demonstrated by the 2Apro‐mediated cleavage of dystrophin in cardiomyocytes contributing to Coxsackievirus‐induced cardiomyopathy. It is likely that improved tools to identify targets for these proteases will reveal additional host protein substrates that can be linked to specific enterovirus‐associated diseases. Here, we discuss the function of the enteroviral proteases in the virus replication cycle and review the current knowledge regarding how these proteases modulate the infected cell in order to favour virus replication, including ways to avoid detection by the immune system. We also highlight new possibilities for the identification of protease‐specific cellular targets and thereby a way to discover novel mechanisms contributing to disease. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Olli H Laitinen
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland
| | - Emma Svedin
- The Center for Infectious Medicine, Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
| | - Sebastian Kapell
- The Center for Infectious Medicine, Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
| | - Anssi Nurminen
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland
| | - Vesa P Hytönen
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland
| | - Malin Flodström-Tullberg
- BioMediTech, Finland and Fimlab Laboratories, University of Tampere, Tampere, Finland.,The Center for Infectious Medicine, Department of Medicine HS, Karolinska Institutet, Stockholm, Sweden
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19
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Generation of Recombinant Polioviruses Harboring RNA Affinity Tags in the 5' and 3' Noncoding Regions of Genomic RNAs. Viruses 2016; 8:v8020039. [PMID: 26861382 PMCID: PMC4776194 DOI: 10.3390/v8020039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 01/18/2016] [Accepted: 01/21/2016] [Indexed: 12/30/2022] Open
Abstract
Despite being intensely studied for more than 50 years, a complete understanding of the enterovirus replication cycle remains elusive. Specifically, only a handful of cellular proteins have been shown to be involved in the RNA replication cycle of these viruses. In an effort to isolate and identify additional cellular proteins that function in enteroviral RNA replication, we have generated multiple recombinant polioviruses containing RNA affinity tags within the 3' or 5' noncoding region of the genome. These recombinant viruses retained RNA affinity sequences within the genome while remaining viable and infectious over multiple passages in cell culture. Further characterization of these viruses demonstrated that viral protein production and growth kinetics were unchanged or only slightly altered relative to wild type poliovirus. However, attempts to isolate these genetically-tagged viral genomes from infected cells have been hindered by high levels of co-purification of nonspecific proteins and the limited matrix-binding efficiency of RNA affinity sequences. Regardless, these recombinant viruses represent a step toward more thorough characterization of enterovirus ribonucleoprotein complexes involved in RNA replication.
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20
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Neurotropic Enterovirus Infections in the Central Nervous System. Viruses 2015; 7:6051-66. [PMID: 26610549 PMCID: PMC4664993 DOI: 10.3390/v7112920] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/06/2015] [Accepted: 11/13/2015] [Indexed: 02/03/2023] Open
Abstract
Enteroviruses are a group of positive-sense single stranded viruses that belong to the Picornaviridae family. Most enteroviruses infect humans from the gastrointestinal tract and cause mild symptoms. However, several enteroviruses can invade the central nervous system (CNS) and result in various neurological symptoms that are correlated to mortality associated with enteroviral infections. In recent years, large outbreaks of enteroviruses occurred worldwide. Therefore, these neurotropic enteroviruses have been deemed as re-emerging pathogens. Although these viruses are becoming large threats to public health, our understanding of these viruses, especially for non-polio enteroviruses, is limited. In this article, we review recent advances in the trafficking of these pathogens from the peripheral to the central nervous system, compare their cell tropism, and discuss the effects of viral infections in their host neuronal cells.
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21
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Sin J, Mangale V, Thienphrapa W, Gottlieb RA, Feuer R. Recent progress in understanding coxsackievirus replication, dissemination, and pathogenesis. Virology 2015; 484:288-304. [PMID: 26142496 DOI: 10.1016/j.virol.2015.06.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 04/23/2015] [Accepted: 06/03/2015] [Indexed: 01/01/2023]
Abstract
Coxsackieviruses (CVs) are relatively common viruses associated with a number of serious human diseases, including myocarditis and meningo-encephalitis. These viruses are considered cytolytic yet can persist for extended periods of time within certain host tissues requiring evasion from the host immune response and a greatly reduced rate of replication. A member of Picornaviridae family, CVs have been historically considered non-enveloped viruses - although recent evidence suggest that CV and other picornaviruses hijack host membranes and acquire an envelope. Acquisition of an envelope might provide distinct benefits to CV virions, such as resistance to neutralizing antibodies and efficient nonlytic viral spread. CV exhibits a unique tropism for progenitor cells in the host which may help to explain the susceptibility of the young host to infection and the establishment of chronic disease in adults. CVs have also been shown to exploit autophagy to maximize viral replication and assist in unconventional release from target cells. In this article, we review recent progress in clarifying virus replication and dissemination within the host cell, identifying determinants of tropism, and defining strategies utilized by the virus to evade the host immune response. Also, we will highlight unanswered questions and provide future perspectives regarding the potential mechanisms of CV pathogenesis.
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Affiliation(s)
- Jon Sin
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Vrushali Mangale
- The Integrated Regenerative Research Institute (IRRI) at San Diego State University, Cell & Molecular Biology Joint Doctoral Program, Department of Biology, San Diego State University, San Diego, CA 92182-4614, USA
| | - Wdee Thienphrapa
- The Integrated Regenerative Research Institute (IRRI) at San Diego State University, Cell & Molecular Biology Joint Doctoral Program, Department of Biology, San Diego State University, San Diego, CA 92182-4614, USA
| | - Roberta A Gottlieb
- Cedars-Sinai Heart Institute, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
| | - Ralph Feuer
- The Integrated Regenerative Research Institute (IRRI) at San Diego State University, Cell & Molecular Biology Joint Doctoral Program, Department of Biology, San Diego State University, San Diego, CA 92182-4614, USA.
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22
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Flather D, Semler BL. Picornaviruses and nuclear functions: targeting a cellular compartment distinct from the replication site of a positive-strand RNA virus. Front Microbiol 2015; 6:594. [PMID: 26150805 PMCID: PMC4471892 DOI: 10.3389/fmicb.2015.00594] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/29/2015] [Indexed: 11/13/2022] Open
Abstract
The compartmentalization of DNA replication and gene transcription in the nucleus and protein production in the cytoplasm is a defining feature of eukaryotic cells. The nucleus functions to maintain the integrity of the nuclear genome of the cell and to control gene expression based on intracellular and environmental signals received through the cytoplasm. The spatial separation of the major processes that lead to the expression of protein-coding genes establishes the necessity of a transport network to allow biomolecules to translocate between these two regions of the cell. The nucleocytoplasmic transport network is therefore essential for regulating normal cellular functioning. The Picornaviridae virus family is one of many viral families that disrupt the nucleocytoplasmic trafficking of cells to promote viral replication. Picornaviruses contain positive-sense, single-stranded RNA genomes and replicate in the cytoplasm of infected cells. As a result of the limited coding capacity of these viruses, cellular proteins are required by these intracellular parasites for both translation and genomic RNA replication. Being of messenger RNA polarity, a picornavirus genome can immediately be translated upon entering the cell cytoplasm. However, the replication of viral RNA requires the activity of RNA-binding proteins, many of which function in host gene expression, and are consequently localized to the nucleus. As a result, picornaviruses disrupt nucleocytoplasmic trafficking to exploit protein functions normally localized to a different cellular compartment from which they translate their genome to facilitate efficient replication. Furthermore, picornavirus proteins are also known to enter the nucleus of infected cells to limit host-cell transcription and down-regulate innate antiviral responses. The interactions of picornavirus proteins and host-cell nuclei are extensive, required for a productive infection, and are the focus of this review.
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Affiliation(s)
- Dylan Flather
- Department of Microbiology and Molecular Genetics, Center for Virus Research, School of Medicine, University of California, Irvine Irvine, CA, USA
| | - Bert L Semler
- Department of Microbiology and Molecular Genetics, Center for Virus Research, School of Medicine, University of California, Irvine Irvine, CA, USA
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23
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Paul AV, Wimmer E. Initiation of protein-primed picornavirus RNA synthesis. Virus Res 2015; 206:12-26. [PMID: 25592245 DOI: 10.1016/j.virusres.2014.12.028] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 12/16/2014] [Accepted: 12/24/2014] [Indexed: 12/14/2022]
Abstract
Plus strand RNA viruses use different mechanisms to initiate the synthesis of their RNA chains. The Picornaviridae family constitutes a large group of plus strand RNA viruses that possess a small terminal protein (VPg) covalently linked to the 5'-end of their genomes. The RNA polymerases of these viruses use VPg as primer for both minus and plus strand RNA synthesis. In the first step of the initiation reaction the RNA polymerase links a UMP to the hydroxyl group of a tyrosine in VPg using as template a cis-replicating element (cre) positioned in different regions of the viral genome. In this review we will summarize what is known about the initiation reaction of protein-primed RNA synthesis by the RNA polymerases of the Picornaviridae. As an example we will use the RNA polymerase of poliovirus, the prototype of Picornaviridae. We will also discuss models of how these nucleotidylylated protein primers might be used, together with viral and cellular replication proteins and other cis-replicating RNA elements, during minus and plus strand RNA synthesis.
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Affiliation(s)
- Aniko V Paul
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11790, United States.
| | - Eckard Wimmer
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11790, United States
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24
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Schulte MB, Andino R. Single-cell analysis uncovers extensive biological noise in poliovirus replication. J Virol 2014; 88:6205-12. [PMID: 24648454 PMCID: PMC4093869 DOI: 10.1128/jvi.03539-13] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 03/11/2014] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Viral infections often begin with a very small number of initiating particles. Accordingly, the outcome of an infection is likely to be affected by variability in the initial molecular interactions between virus and host. In this study, we investigated the range of outcomes upon infection of single cells. We isolated individual cells infected with poliovirus at low or high multiplicities of infection (MOI) and measured viral genomic replication and infectious viral progeny in each cell. We first determined that at 7 h postinfection, the ratio of positive to negative strands in individual cells varies from 5:1 to more than 190:1, with and average of 20:1, suggesting a significant variability in RNA synthesis. We further found that while virus genome production is higher in cells infected at a high multiplicity, the production of infectious particles is largely independent of the number of viruses infecting each cell. Strikingly, by correlating RNA and particle production within individual infections, we uncovered a significant contribution of stochastic noise to the outcome of infection. At low MOI, stochastic influences appear as kinetic effects which are most critical at the initial steps in infection. At high MOI, stochastic influences appear to dictate the virus's ability to harness cellular resources. We conclude that biological noise is a critical determinant of the overall productivity of viral infections. The distinct nature of stochasticity in the outcome of infection by low and high numbers of viral particles may have important implications for our understanding of the determinants of successful viral infections. IMPORTANCE By correlating genome and particle production in single-cell infections, we elucidated sources of noise in viral infections. When a cell was infected by only a single infectious particle, variation in the kinetics of the initial steps of replication contributed significantly to the overall productivity of the infection. Additionally, variation in the distribution of subcellular resources impacted infections initiated by one or many infectious particles. We also observed that when a cell was infected with multiple particles, more genomes were produced, while particle production was hindered by an apparent cellular resource limit. Understanding variations in viral infections may illuminate the dynamics of infection and pathogenesis and has implications for virus adaptation and evolution.
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Affiliation(s)
- Michael B. Schulte
- Tetrad Graduate Program, University of California, San Francisco, California, USA
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
| | - Raul Andino
- Department of Microbiology and Immunology, University of California, San Francisco, California, USA
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25
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Specific sequence of a Beta turn in human la protein may contribute to species specificity of hepatitis C virus. J Virol 2014; 88:4319-27. [PMID: 24478427 DOI: 10.1128/jvi.00049-14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Human La protein is known to be an essential host factor for translation and replication of hepatitis C virus (HCV) RNA. Previously, we have demonstrated that residues responsible for interaction of human La protein with the HCV internal ribosomal entry site (IRES) around the initiator AUG within stem-loop IV form a β-turn in the RNA recognition motif (RRM) structure. In this study, sequence alignment and mutagenesis suggest that the HCV RNA-interacting β-turn is conserved only in humans and chimpanzees, the species primarily known to be infected by HCV. A 7-mer peptide corresponding to the HCV RNA-interacting region of human La inhibits HCV translation, whereas another peptide corresponding to the mouse La sequence was unable to do so. Furthermore, IRES-mediated translation was found to be significantly high in the presence of recombinant human La protein in vitro in rabbit reticulocyte lysate. We observed enhanced replication with HCV subgenomic and full-length replicons upon overexpression of either human La protein or a chimeric mouse La protein harboring a human La β-turn sequence in mouse cells. Taken together, our results raise the possibility of creating an immunocompetent HCV mouse model using human-specific cell entry factors and a humanized form of La protein. IMPORTANCE Hepatitis C virus is known to infect only humans and chimpanzees under natural conditions. This has prevented the development of a small-animal model, which is important for development of new antiviral drugs. Although a number of human-specific proteins are responsible for this species selectivity and some of these proteins--mostly entry factors--have been identified, full multiplication of the virus in mouse cells is still not possible. In this study, we show that a turn in the human La protein that is responsible for the interaction with the viral RNA is highly specific for the human sequence. Replacement of the corresponding mouse sequence with the human sequence allows the mouse La to behave like its human counterpart and support viral growth in the mouse cell efficiently. This observation, in combination with previously identified cell entry factors, should open up the possibility of creating a mouse model of hepatitis C.
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Human La protein interaction with GCAC near the initiator AUG enhances hepatitis C Virus RNA replication by promoting linkage between 5' and 3' untranslated regions. J Virol 2013; 87:6713-26. [PMID: 23552417 DOI: 10.1128/jvi.00525-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Human La protein has been implicated in facilitating the internal initiation of translation as well as replication of hepatitis C virus (HCV) RNA. Previously, we demonstrated that La interacts with the HCV internal ribosome entry site (IRES) around the GCAC motif near the initiator AUG within stem-loop IV by its RNA recognition motif (RRM) (residues 112 to 184) and influences HCV translation. In this study, we have deciphered the role of this interaction in HCV replication in a hepatocellular carcinoma cell culture system. We incorporated mutation of the GCAC motif in an HCV monocistronic subgenomic replicon and a pJFH1 construct which altered the binding of La and checked HCV RNA replication by reverse transcriptase PCR (RT-PCR). The mutation drastically affected HCV replication. Furthermore, to address whether the decrease in replication is a consequence of translation inhibition or not, we incorporated the same mutation into a bicistronic replicon and observed a substantial decrease in HCV RNA levels. Interestingly, La overexpression rescued this inhibition of replication. More importantly, we observed that the mutation reduced the association between La and NS5B. The effect of the GCAC mutation on the translation-to-replication switch, which is regulated by the interplay between NS3 and La, was further investigated. Additionally, our analyses of point mutations in the GCAC motif revealed distinct roles of each nucleotide in HCV replication and translation. Finally, we showed that a specific interaction of the GCAC motif with human La protein is crucial for linking 5' and 3' ends of the HCV genome. Taken together, our results demonstrate the mechanism of regulation of HCV replication by interaction of the cis-acting element GCAC within the HCV IRES with human La protein.
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Abstract
The encephalomyocarditis virus (EMCV) is a small non-enveloped single-strand RNA virus, the causative agent of not only myocarditis and encephalitis, but also neurological diseases, reproductive disorders and diabetes in many mammalian species. EMCV pathogenesis appears to be viral strain- and host-specific, and a better understanding of EMCV virulence factors is increasingly required. Indeed, EMCV is often used as a model for diabetes and viral myocarditis, and is also widely used in immunology as a double-stranded RNA stimulus in the study of Toll-like as well as cytosolic receptors. However, EMCV virulence and properties have often been neglected. Moreover, EMCV is able to infect humans albeit with a low morbidity. Progress on xenografts, such as pig heart transplantation in humans, has raised safety concerns that need to be explored. In this review we will highlight the biology of EMCV and all known and potential virulence factors.
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Affiliation(s)
- Margot Carocci
- Microbiology Immunology Department, Harvard Medical School, Boston, MA, USA.
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Development of a strand specific real-time RT-qPCR assay for the detection and quantitation of murine norovirus RNA. J Virol Methods 2012; 184:69-76. [PMID: 22626565 DOI: 10.1016/j.jviromet.2012.05.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 05/11/2012] [Accepted: 05/15/2012] [Indexed: 11/22/2022]
Abstract
Murine norovirus (MNV), currently the only norovirus that efficiently replicates in cell culture, is often used as a model system to understand the molecular mechanisms of norovirus replication. MNV is a single stranded positive sense RNA virus of the Caliciviridae family. Replication of MNV involves the synthesis of both full length genomic and sub-genomic RNAs. The replication of these RNAs involves the synthesis of negative strand intermediates. To understand the molecular mechanism of RNA replication and the role of viral and host factors in virus replication, it is necessary to quantify accurately both positive and negative sense RNA molecules of the viral RNA during replication. Increasingly, strand specific reverse transcription-quantitative PCR (RT-qPCR) is becoming the method of choice for this kind of quantitation. Many strategies have been developed to avoid the false priming property of reverse transcriptase and to amplify specifically one strand in the presence of excess opposite strand. In this report, a SYBR based, real time RT-qPCR assay was developed to detect and quantify specifically the negative and the positive sense RNAs of MNV genomic RNA. This assay is based on using a tagged RT primer containing a non-viral sequence at the 5' end of the viral strand specific sequence. This non-viral sequence is then used to amplify selectively the strand specific cDNA at the PCR stage. This assay can be used for a range of MNV strains including MNV-1 and 3, as these are now widely accepted for use in molecular studies. The specificity of this assay was determined by its ability to quantify one strand in the presence of up to 10(6) copies of competitor opposite sense RNA. Using this assay, the production of both strands of MNV-1 RNA was monitored during viral single step growth curve.
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Liu F, Liu Q, Cai Y, Leng Q, Huang Z. Construction and characterization of an infectious clone of coxsackievirus A16. Virol J 2011; 8:534. [PMID: 22165961 PMCID: PMC3283524 DOI: 10.1186/1743-422x-8-534] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 12/13/2011] [Indexed: 11/23/2022] Open
Abstract
Background Coxsackievirus A16 (CVA16) is a member of the Enterovirus genus of the Picornaviridae family and it is a major etiological agent of hand, foot, and mouth disease (HFMD), which is a common illness affecting children. CVA16 possesses a single-stranded positive-sense RNA genome containing approximately 7410 bases. Current understanding of the replication, structure and virulence determinants of CVA16 is very limited, partly due to difficulties in directly manipulating its RNA genome. Results Two overlapping cDNA fragments were amplified by RT-PCR from the genome of the shzh05-1 strain of CVA16, encompassing the nucleotide regions 1-4392 and 4381-7410, respectively. These two fragments were then joined via a native XbaI site to yield a full-length cDNA. A T7 promoter and poly(A) tail were added to the 5' and 3' ends, respectively, forming a full CVA16 cDNA clone. Transfection of RD cells in vitro with RNA transcribed directly from the cDNA clone allowed the recovery of infectious virus in culture. The CVA16 virus recovered from these cultures was functionally and genetically identical to its parent strain. Conclusions We report the first construction and characterization of an infectious cDNA clone of CVA16. The availability of this infectious clone will greatly enhance future virological investigations and vaccine development for CVA16.
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Affiliation(s)
- Fei Liu
- Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200025, China
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Interplay between NS3 protease and human La protein regulates translation-replication switch of Hepatitis C virus. Sci Rep 2011; 1:1. [PMID: 22355520 PMCID: PMC3210691 DOI: 10.1038/srep00001] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Accepted: 03/01/2011] [Indexed: 02/02/2023] Open
Abstract
HCV NS3 protein plays a central role in viral polyprotein processing and RNA replication. We demonstrate that the NS3 protease (NS3pro) domain alone can specifically bind to HCV-IRES RNA, predominantly in the SLIV region. The cleavage activity of the NS3 protease domain is reduced upon HCV-RNA binding. More importantly, NS3pro binding to the SLIV hinders the interaction of La protein, a cellular IRES-trans acting factor required for HCV IRES-mediated translation, resulting in inhibition of HCV-IRES activity. Although overexpression of both NS3pro as well as the full length NS3 protein decreased the level of HCV IRES mediated translation, replication of HCV replicon RNA was enhanced significantly. These observations suggest that the NS3pro binding to HCV IRES reduces translation in favor of RNA replication. The competition between the host factor (La) and the viral protein (NS3) for binding to HCV IRES might regulate the molecular switch from translation to replication of HCV.
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Rhoades RE, Tabor-Godwin JM, Tsueng G, Feuer R. Enterovirus infections of the central nervous system. Virology 2011; 411:288-305. [PMID: 21251690 PMCID: PMC3060663 DOI: 10.1016/j.virol.2010.12.014] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 12/08/2010] [Indexed: 12/15/2022]
Abstract
Enteroviruses (EV) frequently infect the central nervous system (CNS) and induce neurological diseases. Although the CNS is composed of many different cell types, the spectrum of tropism for each EV is considerable. These viruses have the ability to completely shut down host translational machinery and are considered highly cytolytic, thereby causing cytopathic effects. Hence, CNS dysfunction following EV infection of neuronal or glial cells might be expected. Perhaps unexpectedly given their cytolytic nature, EVs may establish a persistent infection within the CNS, and the lasting effects on the host might be significant with unanticipated consequences. This review will describe the clinical aspects of EV-mediated disease, mechanisms of disease, determinants of tropism, immune activation within the CNS, and potential treatment regimes.
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Affiliation(s)
| | | | | | - Ralph Feuer
- Corresponding author. Cell & Molecular Biology Joint Doctoral Program, Department of Biology, San Diego State University, 5500 Campanile Drive; San Diego, CA 92182-4614, USA. Fax: +1 619 594 0777.
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Jurgeit A, Moese S, Roulin P, Dorsch A, Lötzerich M, Lee WM, Greber UF. An RNA replication-center assay for high content image-based quantifications of human rhinovirus and coxsackievirus infections. Virol J 2010; 7:264. [PMID: 20937137 PMCID: PMC2958916 DOI: 10.1186/1743-422x-7-264] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Accepted: 10/11/2010] [Indexed: 01/17/2023] Open
Abstract
Background Picornaviruses are common human and animal pathogens, including polio and rhinoviruses of the enterovirus family, and hepatits A or food-and-mouth disease viruses. There are no effective countermeasures against the vast majority of picornaviruses, with the exception of polio and hepatitis A vaccines. Human rhinoviruses (HRV) are the most prevalent picornaviruses comprising more than one hundred serotypes. The existing and also emerging HRVs pose severe health risks for patients with asthma or chronic obstructive pulmonary disease. Here, we developed a serotype-independent infection assay using a commercially available mouse monoclonal antibody (mabJ2) detecting double-strand RNA. Results Immunocytochemical staining for RNA replication centers using mabJ2 identified cells that were infected with either HRV1A, 2, 14, 16, 37 or coxsackievirus (CV) B3, B4 or A21. MabJ2 labeled-cells were immunocytochemically positive for newly synthesized viral capsid proteins from HRV1A, 14, 16, 37 or CVB3, 4. We optimized the procedure for detection of virus replication in settings for high content screening with automated fluorescence microscopy and single cell analysis. Our data show that the infection signal was dependent on multiplicity, time and temperature of infection, and the mabJ2-positive cell numbers correlated with viral titres determined in single step growth curves. The mabJ2 infection assay was adapted to determine the efficacy of anti-viral compounds and small interfering RNAs (siRNAs) blocking enterovirus infections. Conclusions We report a broadly applicable, rapid protocol to measure infection of cultured cells with enteroviruses at single cell resolution. This assay can be applied to a wide range of plus-sense RNA viruses, and hence allows comparative studies of viral infection biology without dedicated reagents or procedures. This protocol also allows to directly compare results from small compound or siRNA infection screens for different serotypes without the risk of assay specific artifacts.
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Affiliation(s)
- Andreas Jurgeit
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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Direct interaction between two viral proteins, the nonstructural protein 2C and the capsid protein VP3, is required for enterovirus morphogenesis. PLoS Pathog 2010; 6:e1001066. [PMID: 20865167 PMCID: PMC2928791 DOI: 10.1371/journal.ppat.1001066] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Accepted: 07/26/2010] [Indexed: 12/27/2022] Open
Abstract
In spite of decades-long studies, the mechanism of morphogenesis of plus-stranded RNA viruses belonging to the genus Enterovirus of Picornaviridae, including poliovirus (PV), is not understood. Numerous attempts to identify an RNA encapsidation signal have failed. Genetic studies, however, have implicated a role of the non-structural protein 2C(ATPase) in the formation of poliovirus particles. Here we report a novel mechanism in which protein-protein interaction is sufficient to explain the specificity in PV encapsidation. Making use of a novel "reporter virus", we show that a quasi-infectious chimera consisting of the capsid precursor of C-cluster coxsackie virus 20 (C-CAV20) and the nonstructural proteins of the closely related PV translated and replicated its genome with wild type kinetics, whereas encapsidation was blocked. On blind passages, encapsidation of the chimera was rescued by a single mutation either in capsid protein VP3 of CAV20 or in 2C(ATPase) of PV. Whereas each of the single-mutation variants expressed severe proliferation phenotypes, engineering both mutations into the chimera yielded a virus encapsidating with wild type kinetics. Biochemical analyses provided strong evidence for a direct interaction between 2C(ATPase) and VP3 of PV and CAV20. Chimeras of other C-CAVs (CAV20/CAV21 or CAV18/CAV20) were blocked in encapsidation (no virus after blind passages) but could be rescued if the capsid and 2C(ATPase) coding regions originated from the same virus. Our novel mechanism explains the specificity of encapsidation without apparent involvement of an RNA signal by considering that (i) genome replication is known to be stringently linked to translation, (ii) morphogenesis is known to be stringently linked to genome replication, (iii) newly synthesized 2C(ATPase) is an essential component of the replication complex, and (iv) 2C(ATPase) has specific affinity to capsid protein(s). These conditions lead to morphogenesis at the site where newly synthesized genomes emerge from the replication complex.
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Jang SY, Jeong WH, Kim MS, Lee YM, Lee JI, Lee GC, Paik SY, Koh GP, Kim JM, Lee CH. Detection of replicating negative-sense RNAs in CaCo-2 cells infected with human astrovirus. Arch Virol 2010; 155:1383-9. [PMID: 20544235 DOI: 10.1007/s00705-010-0718-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 05/31/2010] [Indexed: 10/19/2022]
Abstract
Human astrovirus (HAstV) is the second most important cause of viral diarrhea and acute gastroenteritis in infants under five. However, determination of the infectivity of clinical isolates is difficult, and the replication cycle of HAstV is not yet fully understood. In this study, it was attempted to detect negative-sense (-)RNAs generated during the replication of RNA viruses. We used clinical isolates of HAstV to infect CaCo-2 cells. Reverse transcription using only a sense primer followed by PCR using both sense and antisense primers showed that (-)RNAs were first detected in CaCo-2 cells between 9 and 12 h postinfection (p.i.). However, these (-)RNAs were not detected when cells were treated with the protein synthesis inhibitor cycloheximide during HAstV infection. Next, RT with only an antisense primer followed by PCR was performed to detect (+)RNA of HAstVs after production of (-)RNAs during replication. RT-PCR results using the antisense primer revealed that the amount of (+)RNA began to increase starting 9 h p.i., indicating an accumulation of the newly synthesized (+)RNA genome. Cycloheximide was observed to abrogate the increase of newly made (+)RNA during HAstV infection. In conclusion, the use of sense or antisense primers during the RT reaction together with cycloheximide enabled us to quantitatively detect (-)RNAs, and this proved to be an useful tool in understanding the replication cycle of HAstV.
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Affiliation(s)
- So Young Jang
- Department of Microbiology, College of Natural Sciences, Chungbuk National University, Cheongju, Chungbuk, South Korea
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Thébaud G, Chadœuf J, Morelli MJ, McCauley JW, Haydon DT. The relationship between mutation frequency and replication strategy in positive-sense single-stranded RNA viruses. Proc Biol Sci 2010; 277:809-17. [PMID: 19906671 PMCID: PMC2842737 DOI: 10.1098/rspb.2009.1247] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 10/22/2009] [Indexed: 01/21/2023] Open
Abstract
For positive-sense single-stranded RNA virus genomes, there is a trade-off between the mutually exclusive tasks of transcription, translation and encapsidation. The replication strategy that maximizes the intracellular growth rate of the virus requires iterative genome transcription from positive to negative, and back to positive sense. However, RNA viruses experience high mutation rates, and the proportion of genomes with lethal mutations increases with the number of replication cycles. Thus, intracellular mutant frequency will depend on the replication strategy. Introducing apparently realistic mutation rates into a model of viral replication demonstrates that strategies that maximize viral growth rate could result in an average of 26 mutations per genome by the time plausible numbers of positive strands have been generated, and that virus viability could be as low as 0.1 per cent. At high mutation rates or when a high proportion of mutations are deleterious, the optimal strategy shifts towards synthesizing more negative strands per positive strand, and in extremis towards a 'stamping-machine' replication mode where all the encapsidated genomes come from only two transcriptional steps. We conclude that if viral mutation rates are as high as current estimates suggest, either mutation frequency must be considerably higher than generally anticipated and the proportion of viable viruses produced extremely small, or replication strategies cannot be optimized to maximize viral growth rate. Mechanistic models linking mutation frequency to replication mechanisms coupled with data generated through new deep-sequencing technologies could play an important role in improving the estimates of viral mutation rate.
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Affiliation(s)
- Gaël Thébaud
- Institut National de la Recherche Agronomique (INRA), UMR BGPI, Cirad TA A-54/K, Campus de Baillarguet, 34398 Montpellier cedex 5, France
| | - Joël Chadœuf
- INRA, UR546 Biostatistique et Processus Spatiaux, Domaine Saint-Paul, 84914 Avignon, France
| | - Marco J. Morelli
- Boyd Orr Centre for Population and Ecosystem Health, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - John W. McCauley
- The National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Daniel T. Haydon
- Boyd Orr Centre for Population and Ecosystem Health, Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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Brunner JE, Ertel KJ, Rozovics JM, Semler BL. Delayed kinetics of poliovirus RNA synthesis in a human cell line with reduced levels of hnRNP C proteins. Virology 2010; 400:240-7. [PMID: 20189623 PMCID: PMC2844484 DOI: 10.1016/j.virol.2010.01.031] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2009] [Revised: 10/21/2009] [Accepted: 01/27/2010] [Indexed: 02/08/2023]
Abstract
The hnRNP C heterotetramer [(C13)C2] binds RNA polymerase II transcripts in the nucleus, along with other proteins of the core hnRNP complex, and plays an important role in mRNA biogenesis and transport. Infection of HeLa cells with poliovirus causes hnRNP C to re-localize from the nucleus, where it is normally retained during interphase, to the cytoplasm. We have proposed that in the cytoplasm, the protein isoforms of hnRNP C participate in the recognition of viral specific RNAs by the poliovirus replication proteins and/or in the assembly of membrane-bound RNA replication complexes. In SK-OV-3 cells, which express reduced levels of hnRNP C compared to HeLa cells or 293 cells, the kinetics of poliovirus replication are delayed. hnRNP C is also re-localized from the nucleus to the cytoplasm in SK-OV-3 cells infected with poliovirus. Increased expression of hnRNP C in SK-OV-3 cells by transient transfection increases the rate of virus production and overall yield over that seen in mock-transfected cells. We propose that hnRNP C interacts with poliovirus RNA and replication proteins to increase the efficiency of viral genomic RNA synthesis.
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Affiliation(s)
- Jo Ellen Brunner
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California, Irvine, CA 92697, USA
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Nedialkova DD, Gorbalenya AE, Snijder EJ. Arterivirus Nsp1 modulates the accumulation of minus-strand templates to control the relative abundance of viral mRNAs. PLoS Pathog 2010; 6:e1000772. [PMID: 20174607 PMCID: PMC2824749 DOI: 10.1371/journal.ppat.1000772] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 01/14/2010] [Indexed: 12/18/2022] Open
Abstract
The gene expression of plus-strand RNA viruses with a polycistronic genome depends on translation and replication of the genomic mRNA, as well as synthesis of subgenomic (sg) mRNAs. Arteriviruses and coronaviruses, distantly related members of the nidovirus order, employ a unique mechanism of discontinuous minus-strand RNA synthesis to generate subgenome-length templates for the synthesis of a nested set of sg mRNAs. Non-structural protein 1 (nsp1) of the arterivirus equine arteritis virus (EAV), a multifunctional regulator of viral RNA synthesis and virion biogenesis, was previously implicated in controlling the balance between genome replication and sg mRNA synthesis. Here, we employed reverse and forward genetics to gain insight into the multiple regulatory roles of nsp1. Our analysis revealed that the relative abundance of viral mRNAs is tightly controlled by an intricate network of interactions involving all nsp1 subdomains. Distinct nsp1 mutations affected the quantitative balance among viral mRNA species, and our data implicate nsp1 in controlling the accumulation of full-length and subgenome-length minus-strand templates for viral mRNA synthesis. The moderate differential changes in viral mRNA abundance of nsp1 mutants resulted in similarly altered viral protein levels, but progeny virus yields were greatly reduced. Pseudorevertant analysis provided compelling genetic evidence that balanced EAV mRNA accumulation is critical for efficient virus production. This first report on protein-mediated, mRNA-specific control of nidovirus RNA synthesis reveals the existence of an integral control mechanism to fine-tune replication, sg mRNA synthesis, and virus production, and establishes a major role for nsp1 in coordinating the arterivirus replicative cycle. Plus-strand RNA viruses, a major group of plant and animal pathogens, employ a variety of gene expression strategies. In some groups, the genome is translated into a single polyprotein precursor comprising all viral proteins, while the expression of genomes containing multiple open reading frames commonly depends on the production of additional, subgenomic mRNAs. These serve to translate the open reading frames that are inaccessible to host cell ribosomes engaged in genome translation. Arteriviruses and coronaviruses secure the expression of their structural protein genes by generating an extensive nested set of subgenomic mRNAs, which are copied from a set of complementary minus-strand templates. The production of these subgenome-length minus strands involves a unique mechanism of discontinuous RNA synthesis that essentially competes with the production of the full-length minus strand, the template for genome replication. We describe here that arterivirus non-structural protein 1 (nsp1) modulates the accumulation of minus-strand RNAs to control the relative abundance of both genome-length and subgenomic mRNAs, thereby ensuring efficient production of new virus particles. We found that specific nsp1 mutants with imbalanced mRNA levels and low virus production rapidly acquire additional nsp1 mutations that rescue these defects. Thus, a single arterivirus protein plays a decisive role in the integral control of replication, sg mRNA synthesis, and virus production.
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Affiliation(s)
- Danny D. Nedialkova
- Molecular Virology Laboratory, Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Alexander E. Gorbalenya
- Molecular Virology Laboratory, Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
| | - Eric J. Snijder
- Molecular Virology Laboratory, Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
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Mechanistic consequences of hnRNP C binding to both RNA termini of poliovirus negative-strand RNA intermediates. J Virol 2010; 84:4229-42. [PMID: 20164237 DOI: 10.1128/jvi.02198-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The poliovirus 3' noncoding region (3' NCR) is necessary for efficient virus replication. A poliovirus mutant, PVDelta3'NCR, with a deletion of the entire 3' NCR, yielded a virus that was capable of synthesizing viral RNA, albeit with a replication defect caused by deficient positive-strand RNA synthesis compared to wild-type virus. We detected multiple ribonucleoprotein (RNP) complexes in extracts from poliovirus-infected HeLa cells formed with a probe corresponding to the 5' end of poliovirus negative-strand RNA (the complement of the genomic 3' NCR), and the levels of these RNP complexes increased during the course of viral infection. Previous studies have identified RNP complexes formed with the 3' end of poliovirus negative-strand RNA, including one that contains a 36-kDa protein later identified as heterogeneous nuclear ribonucleoprotein C (hnRNP C). We report here that the 5' end of poliovirus negative-strand RNA is capable of interacting with endogenous hnRNP C, as well as with poliovirus nonstructural proteins. Further, we demonstrate that the addition of recombinant purified hnRNP C proteins can stimulate virus RNA synthesis in vitro and that depletion of hnRNP C proteins in cultured cells results in decreased virus yields and a correspondingly diminished accumulation of positive-strand RNAs. We propose that the association of hnRNP C with poliovirus negative-strand termini acts to stabilize or otherwise promote efficient positive-strand RNA synthesis.
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Six RNA viruses and forty-one hosts: viral small RNAs and modulation of small RNA repertoires in vertebrate and invertebrate systems. PLoS Pathog 2010; 6:e1000764. [PMID: 20169186 PMCID: PMC2820531 DOI: 10.1371/journal.ppat.1000764] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Accepted: 01/13/2010] [Indexed: 01/02/2023] Open
Abstract
We have used multiplexed high-throughput sequencing to characterize changes in small RNA populations that occur during viral infection in animal cells. Small RNA-based mechanisms such as RNA interference (RNAi) have been shown in plant and invertebrate systems to play a key role in host responses to viral infection. Although homologs of the key RNAi effector pathways are present in mammalian cells, and can launch an RNAi-mediated degradation of experimentally targeted mRNAs, any role for such responses in mammalian host-virus interactions remains to be characterized. Six different viruses were examined in 41 experimentally susceptible and resistant host systems. We identified virus-derived small RNAs (vsRNAs) from all six viruses, with total abundance varying from “vanishingly rare” (less than 0.1% of cellular small RNA) to highly abundant (comparable to abundant micro-RNAs “miRNAs”). In addition to the appearance of vsRNAs during infection, we saw a number of specific changes in host miRNA profiles. For several infection models investigated in more detail, the RNAi and Interferon pathways modulated the abundance of vsRNAs. We also found evidence for populations of vsRNAs that exist as duplexed siRNAs with zero to three nucleotide 3′ overhangs. Using populations of cells carrying a Hepatitis C replicon, we observed strand-selective loading of siRNAs onto Argonaute complexes. These experiments define vsRNAs as one possible component of the interplay between animal viruses and their hosts. Short RNAs derived from invading viruses with RNA genomes are important components of antiviral immunity in plants, worms and flies. The regulated generation of these short RNAs, and their engagement by the immune apparatus, is essential for inhibiting viral growth in these organisms. Mammals have the necessary protein components to generate these viral-derived short RNAs (“vsRNAs”), raising the question of whether vsRNAs in mammals are a general feature of infections with RNA viruses. Our work with Hepatitis C, Polio, Dengue, Vesicular Stomatitis, and West Nile viruses in a broad host repertoire demonstrates the generality of RNA virus-derived vsRNA production, and the ability of the cellular short RNA apparatus to engage these vsRNAs in mammalian cells. Detailed analyses of vsRNA and host-derived short RNA populations demonstrate both common and virus-specific features of the interplay between viral infection and short RNA populations. The vsRNA populations described in this work represent a novel dimension in both viral pathogenesis and host response.
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Tuiskunen A, Leparc-Goffart I, Boubis L, Monteil V, Klingström J, Tolou HJ, Lundkvist A, Plumet S. Self-priming of reverse transcriptase impairs strand-specific detection of dengue virus RNA. J Gen Virol 2009; 91:1019-27. [PMID: 19940062 DOI: 10.1099/vir.0.016667-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Dengue virus infection is the most frequent arthropod-borne infection affecting humans in the world. Our understanding of the pathophysiological events leading to mild or severe outcomes of the disease remains limited by the fact that viral target cells in the human body are poorly characterized. One of the most sensitive strategies for detecting cells supporting active replication of this positive-strand RNA virus is the search for the replicative intermediate, an antigenome of negative polarity, by RT-PCR. However, a phenomenon described as 'false priming' of the reverse transcriptase (RT) prevents strand-specific detection. The results of the current study showed that this event corresponds to cDNA synthesis that is independent of any primer addition. This property was general to all RNAs tested and was not associated with small free nucleic acids, such as tRNAs and microRNAs. Rather, it corresponded to initiation of cDNA synthesis from the 3' end of the RNA template, and a model is proposed in which the template RNA snaps back upon itself and creates a transient RNA primer suitable for the RT. Such a property would explain why many assays proposed for detection of a replicative intermediate are not specific, and may help in the development of a molecular biology protocol that could allow replication studies of RNA viruses of human interest, such as dengue virus, hepatitis C virus and enteroviruses.
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Affiliation(s)
- A Tuiskunen
- Unité de Virologie Tropicale, IRBA-Marseille (IMTSSA), allée du Med. Col. Jamot, Parc du Pharo, BP 60109, 13262 Marseille Cedex 07, France
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Lambertini E, Spencer SK, Bertz PD, Loge FJ, Borchardt MA. New mathematical approaches to quantify human infectious viruses from environmental media using integrated cell culture-qPCR. J Virol Methods 2009; 163:244-52. [PMID: 19835913 DOI: 10.1016/j.jviromet.2009.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 09/28/2009] [Accepted: 10/06/2009] [Indexed: 10/20/2022]
Abstract
Quantifying infectious viruses by cell culture depends on visualizing cytopathic effect, or for integrated cell culture-PCR, attaining confidence a PCR-positive signal is the result of virus growth and not inoculum carryover. This study developed mathematical methods to calculate infectious virus numbers based on viral growth kinetics in cell culture. Poliovirus was inoculated into BGM cell monolayers at 10 concentrations from 0.001 to 1000 PFU/ml. Copy numbers of negative-strand RNA, a marker of infectivity for single-stranded positive RNA viruses, were measured over time by qRT-PCR. Growth data were analyzed by two approaches. First, data were fit with a continuous function to estimate directly the initial virus number, expressed as genomic copies. Such estimates correlated with actual inoculum numbers across all concentrations (R(2)=0.62, n=17). Second, the length of lag phase appeared to vary inversely with inoculum titers; hence, standard curves to predict inoculum virus numbers were derived based on three definitions of lag time: (1) time of first detection of (-)RNA, (2) second derivative maximum of the fitted continuous function, and (3) time when the fitted curve crossed a threshold (-)RNA concentration. All three proxies yielded standard curves with R(2)=0.69-0.90 (n=17). The primary advantage of these growth kinetics approaches is being able to quantify virions that are unambiguously infectious, a particular advantage for viruses that do not produce CPE.
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Affiliation(s)
- E Lambertini
- Department of Civil and Environmental Engineering, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, United States.
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42
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Gursinsky T, Schulz B, Behrens SE. Replication of Tomato bushy stunt virus RNA in a plant in vitro system. Virology 2009; 390:250-60. [PMID: 19520410 DOI: 10.1016/j.virol.2009.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Revised: 03/28/2009] [Accepted: 05/13/2009] [Indexed: 11/22/2022]
Abstract
An ideal system to investigate individual determinants of the replication process of (+)-strand RNA viruses is a cell-free extract that supports viral protein and RNA synthesis in a synchronized manner. Here, we applied a translation/replication system based on cytoplasmic extracts of Nicotiana tabacum cells to Tomato bushy stunt virus (TBSV) RNA. In vitro translated TBSV proteins p33 and p92 form viral replicase, which, in the same reaction, accomplishes the entire replication cycle on exogenous TBSV DI or full-length RNA. Tests of mutant TBSV RNAs confirmed the template specificity of the in vitro replication reaction. Complementation experiments ascertained the significance of an earlier identified TBSV host factor. Interestingly, formation of the viral replicase occurs also in the absence of concurrent protein synthesis demonstrating that translation and RNA replication are not functionally linked in this system. Our studies with cell-free extracts of a plant host thus confirmed earlier findings and enabled novel insights into the TBSV RNA replication process.
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Affiliation(s)
- Torsten Gursinsky
- Department Microbial Biotechnology, Institute of Biochemistry and Biotechnology, Faculty of Life Sciences (NatFakI), Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, D-06120 Halle/Saale, Germany
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43
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Paula VS, Perse AS, Amado LA, Morais LM, Lima SMB, Tourinho RS, Gaspar AMC, Pinto MA. Kinetics of hepatitis A virus replication in vivo and in vitro using negative-strand quantitative PCR. Eur J Clin Microbiol Infect Dis 2009; 28:1167-76. [DOI: 10.1007/s10096-009-0759-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 05/10/2009] [Indexed: 11/28/2022]
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Steil BP, Barton DJ. Cis-active RNA elements (CREs) and picornavirus RNA replication. Virus Res 2008; 139:240-52. [PMID: 18773930 DOI: 10.1016/j.virusres.2008.07.027] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 07/25/2008] [Accepted: 07/29/2008] [Indexed: 10/21/2022]
Abstract
Our understanding of picornavirus RNA replication has improved over the past 10 years, due in large part to the discovery of cis-active RNA elements (CREs) within picornavirus RNA genomes. CREs function as templates for the conversion of VPg, the Viral Protein of the genome, into VPgpUpU(OH). These so called CREs are different from the previously recognized cis-active RNA sequences and structures within the 5' and 3' NTRs of picornavirus genomes. Two adenosine residues in the loop of the CRE RNA structures allow the viral RNA-dependent RNA polymerase 3D(Pol) to add two uridine residues to the tyrosine residue of VPg. Because VPg and/or VPgpUpU(OH) prime the initiation of viral RNA replication, the asymmetric replication of viral RNA could not be explained without an understanding of the viral RNA template involved in the conversion of VPg into VPgpUpU(OH) primers. We review the growing body of knowledge regarding picornavirus CREs and discuss how CRE RNAs work coordinately with viral replication proteins and other cis-active RNAs in the 5' and 3' NTRs during RNA replication.
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Affiliation(s)
- Benjamin P Steil
- Department of Microbiology and Program in Molecular Biology, University of Colorado Denver, School of Medicine, United States
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45
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Bessaud M, Autret A, Jegouic S, Balanant J, Joffret ML, Delpeyroux F. Development of a Taqman RT-PCR assay for the detection and quantification of negatively stranded RNA of human enteroviruses: evidence for false-priming and improvement by tagged RT-PCR. J Virol Methods 2008; 153:182-9. [PMID: 18706930 DOI: 10.1016/j.jviromet.2008.07.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 07/09/2008] [Accepted: 07/17/2008] [Indexed: 11/28/2022]
Abstract
Human enteroviruses are among the most common viruses infecting humans. These viruses are known to be able to infect a wide range of tissues and are believed to establish persistent infections. Enteroviruses are positive-sense single-stranded RNA viruses whose replication involves the synthesis of negative strand intermediates. Therefore, the specific detection of negatively stranded viral RNA in tissues or cells is a reliable marker of active enteroviral replication. The present report presents the development of a real-time RT-PCR allowing the specific detection and quantification of negatively stranded viral RNA. Since it was known that specific amplification of single-stranded RNA can be made difficult by false-priming events leading to false-positive or overestimated results, the assay was developed by using a tagged RT primer. This tagged RT-PCR was shown to be able to amplify specifically negative RNA of enteroviruses grown in cell cultures by preventing the amplification of cDNAs generated by false-priming.
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Affiliation(s)
- Maël Bessaud
- Unité postulante de biologie des virus entériques, Institut Pasteur, 25 rue du Dr Roux, 75 015 Paris, France.
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Esfandiarei M, McManus BM. Molecular biology and pathogenesis of viral myocarditis. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:127-55. [PMID: 18039131 DOI: 10.1146/annurev.pathmechdis.3.121806.151534] [Citation(s) in RCA: 273] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Myocarditis is a cardiac disease associated with inflammation and injury of the myocardium. Several viruses have been associated with myocarditis in humans. However, coxsackievirus B3 is still considered the dominant etiological agent. The observed pathology in viral myocarditis is a result of cooperation or teamwork between viral processes and host immune responses at various stages of disease. Both innate and adaptive immune responses are crucial determinants of the severity of myocardial damage, and contribute to the development of chronic myocarditis and dilated cardiomyopathy following acute viral myocarditis. Advances in genomics and proteomics, and in the use of informatics and biostatistics, are allowing unbiased initial evaluations that can be the basis for testable hypotheses about virus pathogenesis and new therapies.
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Affiliation(s)
- Mitra Esfandiarei
- The James Hogg iCAPTURE Center for Cardiovascular and Pulmonary Research, St. Paul's Hospital, Providence Health Care Research Institute, Vancouver, Canada.
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Interaction between polypeptide 3ABC and the 5'-terminal structural elements of the genome of Aichi virus: implication for negative-strand RNA synthesis. J Virol 2008; 82:6161-71. [PMID: 18448525 DOI: 10.1128/jvi.02151-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Secondary structural elements at the 5' end of picornavirus genomic RNA function as cis-acting replication elements and are known to interact specifically with viral P3 proteins in several picornaviruses. In poliovirus, ribonucleoprotein complex formation at the 5' end of the genome is required for negative-strand synthesis. We have previously shown that the 5'-end 115 nucleotides of the Aichi virus genome, which are predicted to fold into two stem-loops (SL-A and SL-C) and one pseudoknot (PK-B), act as a cis-acting replication element and that correct folding of these structures is required for negative-strand synthesis. In this study, we investigated the interaction between the 5'-terminal 120 nucleotides of the genome and the P3 proteins, 3AB, 3ABC, 3C, and 3CD, by gel shift assay and Northwestern analysis. The results showed that 3ABC and 3CD bound to the 5'-terminal region specifically. The binding of 3ABC was observed on both assays, while that of 3CD was detected only on Northwestern analysis. No binding of 3AB or 3C was observed. Binding assays using mutant RNAs demonstrated that disruption of the base pairings of the stem of SL-A and one of the two stem segments of PK-B (stem-B1) abolished the 3ABC binding. In addition, the specific nucleotide sequence of stem-B1 was responsible for the efficient 3ABC binding. These results suggest that the interaction of 3ABC with the 5'-terminal region of the genome is involved in negative-strand synthesis. On the other hand, the ability of 3CD to interact with the 5'-terminal region did not correlate with the RNA replication ability.
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Chapman NM, Kim KS, Drescher KM, Oka K, Tracy S. 5' terminal deletions in the genome of a coxsackievirus B2 strain occurred naturally in human heart. Virology 2008; 375:480-91. [PMID: 18378272 DOI: 10.1016/j.virol.2008.02.030] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 12/19/2007] [Accepted: 02/21/2008] [Indexed: 01/17/2023]
Abstract
Enteroviruses can induce human myocarditis, which can be modeled in mice inoculated with group B coxsackieviruses (CVB) and in which CVB evolve to produce defective, terminally deleted genomes. The 5' non-translated region (NTR) was enzymatically amplified from heart tissue of a fatal case of enterovirus-associated myocarditis in Japan in 2002. While no intact 5' viral genomic termini were detected, 5' terminal deletions ranged in size from 22 to 36 nucleotides. Sequence of the 5' third of this viral genome is of a modern strain, closely related to CVB2 strains isolated in Japan in 2002. A CVB3 chimera containing the 5' NTR with a 22 nt deletion produced progeny virus upon transfection of HeLa cells. When the 5' 22 nucleotide deletion was repaired, the virus induced myocarditis in mice and replicated like wild type virus in murine heart cells. This is the first report of these naturally-occurring defective enteroviral genomes in human myocarditis.
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Affiliation(s)
- Nora M Chapman
- Enterovirus Research Laboratory, Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-6495, USA.
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Herrera M, Grande-Pérez A, Perales C, Domingo E. Persistence of foot-and-mouth disease virus in cell culture revisited: implications for contingency in evolution. J Gen Virol 2008; 89:232-244. [DOI: 10.1099/vir.0.83312-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
If we could rewind the tape of evolution and play it again, would it turn out to be similar to or different from what we know? Obviously, this key question can only be addressed by fragmentary experimental approaches. Twenty-two years ago, we described the establishment of BHK-21 cells persistently infected with foot-and-mouth disease virus (FMDV), a system that displayed as its major biological feature a coevolution of the cells and the resident virus in the course of persistence. Now we report the establishment of two persistently infected cell lines in parallel, starting with the same clones of FMDV and BHK-21 cells used 22 years ago. We have asked whether the evolution of the two newly established cell lines and of the earlier cell line would be similar or different. The main conclusions of the study are: (i) the basic behaviour characterized by virus–cell coevolution is similar in the three carrier cell lines, despite differences in some genetic alterations of FMDV; (ii) a strikingly parallel behaviour has been observed with the two newly established cell lines passaged in parallel, unveiling a deterministic virus behaviour during persistence; and (iii) selective RT-PCR amplifications have detected imbalances in the proportion of positive- versus negative-strand viral RNA, mediated by both viral and cellular factors. The results confirm coevolution of cells and virus as a major and reproducible feature of FMDV persistence in cell culture, and suggest that rapidly evolving viruses may constitute adequate test systems to probe the influence of historical contingency on evolutionary events.
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Affiliation(s)
- Mónica Herrera
- Centro de Biología Molecular ‘Severo Ochoa’ (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Ana Grande-Pérez
- Centro de Biología Molecular ‘Severo Ochoa’ (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Celia Perales
- Centro de Biología Molecular ‘Severo Ochoa’ (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
| | - Esteban Domingo
- Centro de Biología Molecular ‘Severo Ochoa’ (CSIC-UAM), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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50
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Svitkin YV, Sonenberg N. A highly efficient and robust in vitro translation system for expression of picornavirus and hepatitis C virus RNA genomes. Methods Enzymol 2007; 429:53-82. [PMID: 17913619 DOI: 10.1016/s0076-6879(07)29004-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
A Krebs-2 cell-free extract that efficiently translates encephalomyocarditis virus (EMCV) RNA and extensively processes the viral polyprotein is also capable of supporting complete infectious EMCV replication. The system displays high RNA synthesis activity and de novo synthesis of virus up to titers of 2 x 10(7) to 6 x 10(7) plaque-forming units (pfu)/ml. The preparation of Krebs-2 cell extract and methods of analysis of EMCV-specific processes in vitro are described. We also demonstrate that the Krebs-2 cell-free system translates the entire open reading frame of the hepatitis C virus (HCV) RNA and properly processes the viral polyprotein when supplemented with canine microsomal membranes. In addition to processing, other posttranslational modifications of HCV proteins take place in vitro, such as the N-terminal glycosylation of the E1 and the E2 precursor (E2-p7) and phosphorylation of NS5A. The HCV RNA-programmed Krebs-2 cell-free extract should prove very useful as a novel screen for drugs that inhibit NS3-mediated processing. The use of this system should help fill the gap in understanding the regulation of synthesis and maturation of HCV proteins. With further optimization of cell-free conditions, the entire reconstitution of infectious HCV synthesis in vitro might become feasible.
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Affiliation(s)
- Yuri V Svitkin
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
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