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Álvarez ÁL, Arboleya A, Abade dos Santos FA, García-Manso A, Nicieza I, Dalton KP, Parra F, Martín-Alonso JM. Highs and Lows in Calicivirus Reverse Genetics. Viruses 2024; 16:866. [PMID: 38932159 PMCID: PMC11209508 DOI: 10.3390/v16060866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/25/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
In virology, the term reverse genetics refers to a set of methodologies in which changes are introduced into the viral genome and their effects on the generation of infectious viral progeny and their phenotypic features are assessed. Reverse genetics emerged thanks to advances in recombinant DNA technology, which made the isolation, cloning, and modification of genes through mutagenesis possible. Most virus reverse genetics studies depend on our capacity to rescue an infectious wild-type virus progeny from cell cultures transfected with an "infectious clone". This infectious clone generally consists of a circular DNA plasmid containing a functional copy of the full-length viral genome, under the control of an appropriate polymerase promoter. For most DNA viruses, reverse genetics systems are very straightforward since DNA virus genomes are relatively easy to handle and modify and are also (with few notable exceptions) infectious per se. This is not true for RNA viruses, whose genomes need to be reverse-transcribed into cDNA before any modification can be performed. Establishing reverse genetics systems for members of the Caliciviridae has proven exceptionally challenging due to the low number of members of this family that propagate in cell culture. Despite the early successful rescue of calicivirus from a genome-length cDNA more than two decades ago, reverse genetics methods are not routine procedures that can be easily extrapolated to other members of the family. Reports of calicivirus reverse genetics systems have been few and far between. In this review, we discuss the main pitfalls, failures, and delays behind the generation of several successful calicivirus infectious clones.
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Affiliation(s)
- Ángel L. Álvarez
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Aroa Arboleya
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Fábio A. Abade dos Santos
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
- Instituto Nacional de Investigação Agrária e Veterinária, 2780-157 Oeiras, Portugal
| | - Alberto García-Manso
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Inés Nicieza
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Kevin P. Dalton
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
| | - Francisco Parra
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
| | - José M. Martín-Alonso
- Instituto Universitario de Biotecnología de Asturias (IUBA), Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, 33006 Oviedo, Spain
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Sion E, Ab-Rahim S, Muhamad M. Trends on Human Norovirus Virus-like Particles (HuNoV-VLPs) and Strategies for the Construction of Infectious Viral Clones toward In Vitro Replication. Life (Basel) 2023; 13:1447. [PMID: 37511822 PMCID: PMC10381778 DOI: 10.3390/life13071447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 07/30/2023] Open
Abstract
Most acute gastroenteritis (AGE) outbreaks and sporadic cases in developing countries are attributable to infection by human norovirus (HuNoV), the enteric virus mainly transmitted via fecal-contaminated water. However, it has been challenging to study HuNoV due to the lack of suitable systems to cultivate and replicate the virus, hindering the development of treatments and vaccines. Researchers have been using virus-like particles (VLPs) and infectious viral clones to overcome this challenge as alternatives to fresh virus isolates in various in vitro and ex vivo models. VLPs are multiprotein structures that mimic the wild-type virus but cannot replicate in host cells due to the lack of genetic materials for replication, limiting downstream analysis of the virus life cycle and pathogenesis. The development of in vitro cloning systems has shown promise for HuNoV replication studies. This review discusses the approaches for constructing HuNoV-VLPs and infectious viral clones, the techniques involved, and the challenges faced. It also highlights the relationship between viral genes and their protein products and provides a perspective on technical considerations for producing efficient HuNoV-VLPs and infectious viral clones, which could substitute for native human noroviruses in future studies.
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Affiliation(s)
- Emilly Sion
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Selangor Branch, Sungai Buloh Campus, Sungai Buloh 47000, Selangor, Malaysia
| | - Sharaniza Ab-Rahim
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Selangor Branch, Sungai Buloh Campus, Sungai Buloh 47000, Selangor, Malaysia
| | - Mudiana Muhamad
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, Universiti Teknologi MARA, Selangor Branch, Sungai Buloh Campus, Sungai Buloh 47000, Selangor, Malaysia
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Lin SC, Bai GH, Lin PC, Chen CY, Hsu YH, Lee YC, Chen SY. Molecular and Genetics-Based Systems for Tracing the Evolution and Exploring the Mechanisms of Human Norovirus Infections. Int J Mol Sci 2023; 24:ijms24109093. [PMID: 37240438 DOI: 10.3390/ijms24109093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/09/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
Human noroviruses (HuNoV) are major causes of acute gastroenteritis around the world. The high mutation rate and recombination potential of noroviruses are significant challenges in studying the genetic diversity and evolution pattern of novel strains. In this review, we describe recent advances in the development of technologies for not only the detection but also the analysis of complete genome sequences of noroviruses and the future prospects of detection methods for tracing the evolution and genetic diversity of human noroviruses. The mechanisms of HuNoV infection and the development of antiviral drugs have been hampered by failure to develop the infectious virus in a cell model. However, recent studies have demonstrated the potential of reverse genetics for the recovery and generation of infectious viral particles, suggesting the utility of this genetics-based system as an alternative for studying the mechanisms of viral infection, such as cell entry and replication.
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Affiliation(s)
- Sheng-Chieh Lin
- Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
- Division of Allergy, Asthma, and Immunology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
| | - Geng-Hao Bai
- Department of Internal Medicine, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei City 10002, Taiwan
| | - Pei-Chun Lin
- Division of Pediatric Gastroenterology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
| | - Chung-Yung Chen
- Department of Bioscience Technology, Chung Yuan Christian University, Taoyuan City 32023, Taiwan
- Center for Nanotechnology, Institute of Biomedical Technology, Chung Yuan Christian University, Taoyuan City 32023, Taiwan
| | - Yi-Hsiang Hsu
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
- Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Yuan-Chang Lee
- Department of Infectious Diseases, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
- Department of Infectious Diseases, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
| | - Shih-Yen Chen
- Department of Pediatrics, School of Medicine, College of Medicine, Taipei Medical University, Taipei City 11031, Taiwan
- Division of Pediatric Gastroenterology, Department of Pediatrics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan
- TMU Research Center for Digestive Medicine, Taipei Medical University, Taipei City 11031, Taiwan
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Todd KV, Tripp RA. Human Norovirus: Experimental Models of Infection. Viruses 2019; 11:v11020151. [PMID: 30759780 PMCID: PMC6410082 DOI: 10.3390/v11020151] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 02/06/2019] [Accepted: 02/07/2019] [Indexed: 12/21/2022] Open
Abstract
Human noroviruses (HuNoVs) are a leading cause of acute gastroenteritis worldwide. HuNoV infections lead to substantial societal and economic burdens. There are currently no licensed vaccines or therapeutics for the prevention or treatment of HuNoVs. A lack of well-characterized in vitro and in vivo infection models has limited the development of HuNoV countermeasures. Experimental infection of human volunteers and the use of related viruses such as murine NoV have provided helpful insights into HuNoV biology and vaccine and therapeutic development. There remains a need for robust animal models and reverse genetic systems to further HuNoV research. This review summarizes available HuNoV animal models and reverse genetic systems, while providing insight into their usefulness for vaccine and therapeutic development.
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Affiliation(s)
- Kyle V Todd
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| | - Ralph A Tripp
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
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Enosi Tuipulotu D, Netzler NE, Lun JH, Mackenzie JM, White PA. RNA Sequencing of Murine Norovirus-Infected Cells Reveals Transcriptional Alteration of Genes Important to Viral Recognition and Antigen Presentation. Front Immunol 2017; 8:959. [PMID: 28848558 PMCID: PMC5554501 DOI: 10.3389/fimmu.2017.00959] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/26/2017] [Indexed: 01/02/2023] Open
Abstract
Viruses inherently exploit normal cellular functions to promote replication and survival. One mechanism involves transcriptional control of the host, and knowledge of the genes modified and their molecular function can aid in understanding viral-host interactions. Norovirus pathogenesis, despite the recent advances in cell cultivation, remains largely uncharacterized. Several studies have utilized the related murine norovirus (MNV) to identify innate response, antigen presentation, and cellular recognition components that are activated during infection. In this study, we have used next-generation sequencing to probe the transcriptomic changes of MNV-infected mouse macrophages. Our in-depth analysis has revealed that MNV is a potent stimulator of the innate response including genes involved in interferon and cytokine production pathways. We observed that genes involved in viral recognition, namely IFIH1, DDX58, and DHX58 were significantly upregulated with infection, whereas we observed significant downregulation of cytokine receptors (Il17rc, Il1rl1, Cxcr3, and Cxcr5) and TLR7. Furthermore, we identified that pathways involved in protein degradation (including genes Psmb3, Psmb4, Psmb5, Psmb9, and Psme2), antigen presentation, and lymphocyte activation are downregulated by MNV infection. Thus, our findings illustrate that MNV induces perturbations in the innate immune transcriptome, particularly in MHC maturation and viral recognition that can contribute to disease pathogenesis.
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Affiliation(s)
- Daniel Enosi Tuipulotu
- Faculty of Science, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Natalie E Netzler
- Faculty of Science, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jennifer H Lun
- Faculty of Science, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jason M Mackenzie
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Peter A White
- Faculty of Science, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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Eftim SE, Hong T, Soller J, Boehm A, Warren I, Ichida A, Nappier SP. Occurrence of norovirus in raw sewage - A systematic literature review and meta-analysis. WATER RESEARCH 2017; 111:366-374. [PMID: 28110140 DOI: 10.1016/j.watres.2017.01.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/04/2017] [Accepted: 01/06/2017] [Indexed: 05/19/2023]
Abstract
Human noroviruses (NoV) are a leading cause of recreational waterborne illnesses and responsible for the majority of viral-associated gastrointestinal illnesses nationwide. We conducted a systematic literature review of published peer-reviewed publications to identify NoV density data in wastewater influent, and provided an approach for developing pathogen density distributions, using the NoV data. Literature review inclusion criteria included scope, study quality, and data availability. A non-parametric bootstrap statistical model was used to estimate the NoV distribution in wastewater influent. The approach used accounts for heterogeneity in study-specific distribution curves, sampling locations, and sampling season and provides a comprehensive representation of the data. Study results illustrate that pooling all of the available NoV data together in a meta-analysis provides a more comprehensive understanding of the technical literature than what could be appreciated from individual studies. The studies included in this analysis indicate a high density of NoV in wastewater influent (overall mean = 4.6 log10 genome copies (GC)/liter (L)), with a higher density of NoV genogroup (G) II (overall mean = 4.9 log10 GC/L) than for GI (overall mean = 4.4 log10 GC/L for GI). The bootstrapping approach was also used to account for differences in seasonal and geographical occurrences of NoV GI and GII. The methods presented are reproducible and can be used to develop QMRA-ready density distributions for other viral pathogens in wastewater influent, effluent, and ambient waters. To our knowledge, our results are the first to quantitatively characterize seasonal and geographic differences, which could be particularly useful for future risk assessments.
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Affiliation(s)
| | - Tao Hong
- ICF, LLC, 9300 Lee Highway, Fairfax, VA, 22031, USA
| | - Jeffrey Soller
- Soller Environmental, LLC, 3022 King St, Berkeley, CA, 94703, USA
| | | | - Isaac Warren
- ICF, LLC, 9300 Lee Highway, Fairfax, VA, 22031, USA
| | | | - Sharon P Nappier
- U.S. Environmental Protection Agency, Office of Water, Office of Science and Technology, 1200 Pennsylvania Avenue, NW, Washington, DC, 20460, USA
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7
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Infection models of human norovirus: challenges and recent progress. Arch Virol 2016; 161:779-88. [PMID: 26780772 DOI: 10.1007/s00705-016-2748-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/30/2015] [Indexed: 10/22/2022]
Abstract
Human norovirus (hNoV) infections cause acute gastroenteritis, accounting for millions of disease cases and more than 200,000 deaths annually. However, the lack of in vitro infection models and robust small-animal models has posed barriers to the development of virus-specific therapies and preventive vaccines. Promising recent progress in the development of a norovirus infection model is reviewed in this article, as well as attempts and efforts made since the discovery of hNoV more than 40 years ago. Because suitable experimental animal models for human norovirus are lacking, attractive alternatives are also discussed.
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9
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Abstract
Sapoviruses cause acute gastroenteritis in humans and animals. They belong to the genus Sapovirus within the family Caliciviridae. They infect and cause disease in humans of all ages, in both sporadic cases and outbreaks. The clinical symptoms of sapovirus gastroenteritis are indistinguishable from those caused by noroviruses, so laboratory diagnosis is essential to identify the pathogen. Sapoviruses are highly diverse genetically and antigenically. Currently, reverse transcription-PCR (RT-PCR) assays are widely used for sapovirus detection from clinical specimens due to their high sensitivity and broad reactivity as well as the lack of sensitive assays for antigen detection or cell culture systems for the detection of infectious viruses. Sapoviruses were first discovered in 1976 by electron microscopy in diarrheic samples of humans. To date, sapoviruses have also been detected from several animals: pigs, mink, dogs, sea lions, and bats. In this review, we focus on genomic and antigenic features, molecular typing/classification, detection methods, and clinical and epidemiological profiles of human sapoviruses.
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A novel reverse genetics system for human norovirus. Trends Microbiol 2014; 22:604-6. [PMID: 25438616 DOI: 10.1016/j.tim.2014.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 10/06/2014] [Indexed: 11/23/2022]
Abstract
Human noroviruses cause significant morbidity, mortality, and economic losses worldwide. The inability to grow human noroviruses in cell culture has hampered our collective understanding of virus-host interactions and development of therapeutics. A newly described single-plasmid reverse genetics system for noroviruses has the potential to facilitate basic and applied research.
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Plasmid-based human norovirus reverse genetics system produces reporter-tagged progeny virus containing infectious genomic RNA. Proc Natl Acad Sci U S A 2014; 111:E4043-52. [PMID: 25192933 DOI: 10.1073/pnas.1415096111] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Human norovirus (HuNoV) is the leading cause of gastroenteritis worldwide. HuNoV replication studies have been hampered by the inability to grow the virus in cultured cells. The HuNoV genome is a positive-sense single-stranded RNA (ssRNA) molecule with three open reading frames (ORFs). We established a reverse genetics system driven by a mammalian promoter that functions without helper virus. The complete genome of the HuNoV genogroup II.3 U201 strain was cloned downstream of an elongation factor-1α (EF-1α) mammalian promoter. Cells transfected with plasmid containing the full-length genome (pHuNoVU201F) expressed the ORF1 polyprotein, which was cleaved by the viral protease to produce the mature nonstructural viral proteins, and the capsid proteins. Progeny virus produced from the transfected cells contained the complete NoV genomic RNA (VP1, VP2, and VPg) and exhibited the same density in isopycnic cesium chloride gradients as native infectious NoV particles from a patient's stool. This system also was applied to drive murine NoV RNA replication and produced infectious progeny virions. A GFP reporter construct containing the GFP gene in ORF1 produced complete virions that contain VPg-linked RNA. RNA from virions containing the encapsidated GFP-genomic RNA was successfully transfected back into cells producing fluorescent puncta, indicating that the encapsidated RNA is replication-competent. The EF-1α mammalian promoter expression system provides the first reverse genetics system, to our knowledge, generalizable for human and animal NoVs that does not require a helper virus. Establishing a complete reverse genetics system expressed from cDNA for HuNoVs now allows the manipulation of the viral genome and production of reporter virions.
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VPg-primed RNA synthesis of norovirus RNA-dependent RNA polymerases by using a novel cell-based assay. J Virol 2011; 85:13027-37. [PMID: 21994457 DOI: 10.1128/jvi.06191-11] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Molecular studies of human noroviruses (NoV) have been hampered by the lack of a permissive cell culture system. We have developed a sensitive and reliable mammalian cell-based assay for the human NoV GII.4 strain RNA-dependent RNA polymerase (RdRp). The assay is based on the finding that RNAs synthesized by transiently expressed RdRp can stimulate retinoic acid-inducible gene I (RIG-I)-dependent reporter luciferase production via the beta interferon promoter. Comparable activities were observed for the murine norovirus (MNV) RdRp. RdRps with mutations at divalent metal ion binding residues did not activate RIG-I signaling. Furthermore, both NoV and MNV RdRp activities were stimulated by the coexpression of their respective VPg proteins, while mutations in the putative site of nucleotide linkage on VPg abolished most of their stimulatory effects. Sequencing of the RNAs linked to VPg revealed that the cellular trans-Golgi network protein 2 (TGOLN2) mRNA was the template for VPg-primed RNA synthesis. Small interfering RNA knockdown of RNase L abolished the enhancement of signaling that occurred in the presence of VPg. Finally, the coexpression of each of the other NoV proteins revealed that p48 (also known as NS1-2) and VP1 enhanced and that VP2 reduced the RdRp activity. The assay should be useful for the dissection of the requirements for NoV RNA synthesis as well as the identification of inhibitors of the NoV RdRp.
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Oka T, Murakami K, Wakita T, Katayama K. Comparative site-directed mutagenesis in the catalytic amino acid triad in calicivirus proteases. Microbiol Immunol 2011; 55:108-14. [PMID: 21204947 DOI: 10.1111/j.1348-0421.2010.00295.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Calicivirus proteases cleave the viral precursor polyprotein encoded by open reading frame 1 (ORF1) into multiple intermediate and mature proteins. These proteases have conserved histidine (His), glutamic acid (Glu) or aspartic acid (Asp), and cysteine (Cys) residues that are thought to act as a catalytic triad (i.e. general base, acid and nucleophile, respectively). However, is the triad critical for processing the polyprotein? In the present study, we examined these amino acids in viruses representing the four major genera of Caliciviridae: Norwalk virus (NoV), Rabbit hemorrhagic disease virus (RHDV), Sapporo virus (SaV) and Feline calicivirus (FCV). Using single amino-acid substitutions, we found that an acidic amino acid (Glu or Asp), as well as the His and Cys in the putative catalytic triad, cannot be replaced by Ala for normal processing activity of the ORF1 polyprotein in vitro. Similarly, normal activity is not retained if the nucleophile Cys is replaced with Ser. These results showed the calicivirus protease is a Cys protease and the catalytic triad formation is important for protease activity. Our study is the first to directly compare the proteases of the four representative calicivirus genera. Interestingly, we found that RHDV and SaV proteases critically need the acidic residues during catalysis, whereas proteolytic cleavage occurs normally at several cleavage sites in the ORF1 polyprotein without a functional acid residue in the NoV and FCV proteases. Thus, the substrate recognition mechanism may be different between the SaV and RHDV proteases and the NoV and FCV proteases.
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Affiliation(s)
- Tomoichiro Oka
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan.
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Yezli S, Otter JA. Minimum Infective Dose of the Major Human Respiratory and Enteric Viruses Transmitted Through Food and the Environment. FOOD AND ENVIRONMENTAL VIROLOGY 2011; 3:1-30. [PMID: 35255645 PMCID: PMC7090536 DOI: 10.1007/s12560-011-9056-7] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 02/26/2011] [Indexed: 05/18/2023]
Abstract
Viruses are a significant cause of morbidity and mortality around the world. Determining the minimum dose of virus particles that can initiate infection, termed the minimum infective dose (MID), is important for the development of risk assessment models in the fields of food and water treatment and the implementation of appropriate infection control strategies in healthcare settings. Both respiratory and enteric viruses can be shed at high titers from infected individuals even when the infection is asymptomatic. Presence of pre-existing antibodies has been shown to affect the infectious dose and to be protective against reinfection for many, but not all viruses. Most respiratory viruses appear to be as infective in humans as in tissue culture. Doses of <1 TCID50 of influenza virus, rhinovirus, and adenovirus were reported to infect 50% of the tested population. Similarly, low doses of the enteric viruses, norovirus, rotavirus, echovirus, poliovirus, and hepatitis A virus, caused infection in at least some of the volunteers tested. A number of factors may influence viruses' infectivity in experimentally infected human volunteers. These include host and pathogen factors as well as the experimental methodology. As a result, the reported infective doses of human viruses have to be interpreted with caution.
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Affiliation(s)
- Saber Yezli
- Bioquell UK Ltd, 52 Royce Close, West Portway, Andover, Hampshire, SP10 3TS, UK.
| | - Jonathan A Otter
- Bioquell UK Ltd, 52 Royce Close, West Portway, Andover, Hampshire, SP10 3TS, UK
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Bull RA, Hyde J, Mackenzie JM, Hansman GS, Oka T, Takeda N, White PA. Comparison of the replication properties of murine and human calicivirus RNA-dependent RNA polymerases. Virus Genes 2010; 42:16-27. [PMID: 20960046 DOI: 10.1007/s11262-010-0535-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/28/2010] [Indexed: 11/28/2022]
Abstract
The human caliciviruses (CV), norovirus (NoV) and sapovirus (SaV), are major causes of outbreak gastroenteritis worldwide. To date, the investigation of human NoV and SaV replication cycles has been impeded as neither is culturable. Consequently, the recently discovered murine NoV (MNV) has been adopted as a surrogate replication model for the human CVs. In this study, we sought to compare the biochemical properties of the MNV RNA-dependent RNA polymerase (RdRp) with related human NoV and SaV-RdRps to address the suitability of MNV as a model for the human CVs. Three human NoV-RdRps (GII.b, GII.4 and GII.7), an MNV-RdRp and two human SaV-RdRps (GI and GII) were overexpressed in Escherichia coli, purified and their enzymatic activity and fidelity compared. Despite ~70% amino acid variation between the RdRp from the two different CV genera, the majority of the physiological characteristics of the RdRps were similar. All RdRps exhibited co-operative dimerisation and had optimal activity at 25°C, a pH range between 7 and 8, required 2-5 mM MnCl(2) and were inhibited with increasing NaCl concentrations. We observed RdRp activity at temperatures as low as 5°C and as high as 65°C. Using an in vitro fidelity assay, similar mutation rates were observed for the separate RdRps (1 × 10(-4)-1 × 10(-5)). This is the first report to compare the physiological, biochemical and mutational properties of the MNV-RdRp to those of the human CV-RdRps and it suggests that MNV may be directly applicable to the study of human NoV.
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Affiliation(s)
- Rowena A Bull
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, The University of New South Wales, Sydney, NSW 2052, Australia.
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Lay MK, Atmar RL, Guix S, Bharadwaj U, He H, Neill FH, Sastry JK, Yao Q, Estes MK. Norwalk virus does not replicate in human macrophages or dendritic cells derived from the peripheral blood of susceptible humans. Virology 2010; 406:1-11. [PMID: 20667573 PMCID: PMC2933743 DOI: 10.1016/j.virol.2010.07.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 01/08/2010] [Accepted: 07/01/2010] [Indexed: 12/20/2022]
Abstract
Human noroviruses are difficult to study due to the lack of an efficient in vitro cell culture system or small animal model. Murine norovirus replicates in murine macrophages (MPhi) and dendritic cells (DCs), raising the possibility that human NoVs might replicate in such human cell types. To test this hypothesis, we evaluated DCs and MPhi derived from monocyte subsets and CD11c(+) DCs isolated from peripheral blood mononuclear cells of individuals susceptible to Norwalk virus (NV) infection. These cells were exposed to NV and replication was evaluated by immunofluorescence and by quantitative RT-PCR. A few PBMC-derived DCs expressed NV proteins. However, NV RNA did not increase in any of the cells tested. These results demonstrate that NV does not replicate in human CD11c(+) DCs, monocyte-derived DCs and MPhi, but abortive infection may occur in a few DCs. These results suggest that NV tropism is distinct from that of murine noroviruses.
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Affiliation(s)
- Margarita K. Lay
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Robert L. Atmar
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Susana Guix
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Uddalak Bharadwaj
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hong He
- Department of Immunology, the University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Frederick H. Neill
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jagannadha K. Sastry
- Department of Immunology, the University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Qizhi Yao
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mary K. Estes
- Department of Molecular Virology & Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
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17
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[Survival strategies of human norovirus]. Uirusu 2010; 60:21-32. [PMID: 20848862 DOI: 10.2222/jsv.60.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Human norovirus is a mutatable non-enveloped RNA virus capable of causing acute gastroenteritis in humans. Thus far, no experimental systems can propagate this virus in large amounts. Recent progresses in viral genomics and bioinformatics have led to a better understanding of molecular evolution of this virus in human populations. In addition, progresses in studies of the related noroviruses, those are replicable in laboratory systems, have led to a rapid accumulation of information on structural biology of norovirus. Furthermore, progresses in public health and water environment researches have led to a better understanding of viral ecology. In this review, I will first summarize fundamental characteristics of norovirus and its molecules. Then, I will summarize structure and molecular evolution of norovirus GII/4 subtype, which is now responsible for majorities of norovirus outbreaks in the world. Finally I will discuss survival strategies of human norovirus in nature by integrating the information.
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18
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Karst SM. Pathogenesis of noroviruses, emerging RNA viruses. Viruses 2010; 2:748-781. [PMID: 21994656 PMCID: PMC3185648 DOI: 10.3390/v2030748] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 03/15/2010] [Accepted: 03/15/2010] [Indexed: 12/13/2022] Open
Abstract
Human noroviruses in the family Caliciviridae are a major cause of epidemic gastroenteritis. They are responsible for at least 95% of viral outbreaks and over 50% of all outbreaks worldwide. Transmission of these highly infectious plus-stranded RNA viruses occurs primarily through contaminated food or water, but also through person-to-person contact and exposure to fomites. Norovirus infections are typically acute and self-limited. However, disease can be much more severe and prolonged in infants, elderly, and immunocompromised individuals. Norovirus outbreaks frequently occur in semi-closed communities such as nursing homes, military settings, schools, hospitals, cruise ships, and disaster relief situations. Noroviruses are classified as Category B biodefense agents because they are highly contagious, extremely stable in the environment, resistant to common disinfectants, and associated with debilitating illness. The number of reported norovirus outbreaks has risen sharply since 2002 suggesting the emergence of more infectious strains. There has also been increased recognition that noroviruses are important causes of childhood hospitalization. Moreover, noroviruses have recently been associated with multiple clinical outcomes other than gastroenteritis. It is unclear whether these new observations are due to improved norovirus diagnostics or to the emergence of more virulent norovirus strains. Regardless, it is clear that human noroviruses cause considerable morbidity worldwide, have significant economic impact, and are clinically important emerging pathogens. Despite the impact of human norovirus-induced disease and the potential for emergence of highly virulent strains, the pathogenic features of infection are not well understood due to the lack of a cell culture system and previous lack of animal models. This review summarizes the current understanding of norovirus pathogenesis from the histological to the molecular level, including contributions from new model systems.
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Affiliation(s)
- Stephanie M. Karst
- Center for Molecular and Tumor Virology, Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130-3932, USA; E-Mail: ; Tel.: +1-318-675-8122; Fax: +1-318-675-5764
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19
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Shirasaki N, Matsushita T, Matsui Y, Oshiba A, Ohno K. Estimation of norovirus removal performance in a coagulation-rapid sand filtration process by using recombinant norovirus VLPs. WATER RESEARCH 2010; 44:1307-1316. [PMID: 19922975 DOI: 10.1016/j.watres.2009.10.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 10/02/2009] [Accepted: 10/29/2009] [Indexed: 05/27/2023]
Abstract
Norovirus (NV) is an important human pathogen that causes epidemic acute nonbacterial gastroenteritis worldwide. Because of the lack of a cell culture system or an animal model for this virus, studies of drinking water treatment such as separation and disinfection processes are still hampered. We successfully estimated NV removal performance during a coagulation-rapid sand filtration process by using recombinant NV virus-like particles (rNV-VLPs) morphologically and antigenically similar to native NV. The behaviors of two widely accepted surrogates for pathogenic waterborne viruses, bacteriophages Qbeta and MS2, were also investigated for comparison with that of rNV-VLPs. Approximately 3-log(10) removals were observed for rNV-VLPs with a dose of 40 muM-Al or -Fe, as polyaluminum chloride at pH 6.8 or ferric chloride at pH 5.8, respectively. Smaller removal ratios were obtained with alum and ferric chloride at pH 6.8. The removal performance for MS2 was somewhat larger than that for rNV-VLPs, meaning that MS2 is not recommended as an appropriate surrogate for native NV. By comparison, the removal performance for Qbeta was similar to, or smaller than, that for rNV-VLPs. However, the removal performances for rNV-VLPs and Qbeta differed between the coagulation process and the following rapid sand filtration process. Therefore, Qbeta also is not recommended as an appropriate surrogate for native NV.
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Affiliation(s)
- N Shirasaki
- Division of Built Environment, Graduate School of Engineering, Hokkaido University, N13W8, Sapporo 060-8628, Japan.
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20
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Gastañaduy AS, Bégué RE. Acute gastroenteritis viruses. Infect Dis (Lond) 2010. [PMCID: PMC7173416 DOI: 10.1016/b978-0-323-04579-7.00151-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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21
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Oka T, Yokoyama M, Katayama K, Tsunemitsu H, Yamamoto M, Miyashita K, Ogawa S, Motomura K, Mori H, Nakamura H, Wakita T, Takeda N, Sato H. Structural and biological constraints on diversity of regions immediately upstream of cleavage sites in calicivirus precursor proteins. Virology 2009; 394:119-29. [PMID: 19747709 DOI: 10.1016/j.virol.2009.08.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2009] [Revised: 07/07/2009] [Accepted: 08/07/2009] [Indexed: 11/28/2022]
Abstract
To address the regulation and evolution of precursor protein cleavability in caliciviruses, we examined constraints on diversity of upstream regions of calicivirus precursor cleavage sites. We performed alanine scanning and supplementary mutagenesis of amino acids at P1, P2, P3, and P4 sites using four viruses representing the four major genera of the family Caliciviridae. This study complements previous mutagenesis studies and shows strong restrictions in mutations at the P1 and P4 sites for effective cleavage reactions. By contrast, such restrictions were less frequently observed at the P2 and P3 sites. Shannon entropy analysis of the reported sequences showed that the P2, P3, and P4 sites allow variations in amino acid size within a calicivirus genus whereas the P1 sites do not. Notably, the human sapovirus precursor protein exceptionally retains a basic rather than aromatic amino acid at the P4 site of the NS4/NS5 cleavage site in reported strains, and a substitution from basic to aromatic amino acid significantly enhanced cleavability at this site. Taken together, these data suggest the existence of (i) structural constraints on the P1 site that restrict size changes within each calicivirus genus, (ii) plastic substrate surfaces that accommodate size variation at the P2, P3, and P4 sites and modulate their own cleavabilities, and (iii) biological constraints on the P4 site that maintain the lower cleavability of the NS4/NS5 site in sapovirus.
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Affiliation(s)
- Tomoichiro Oka
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan.
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22
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Atmar RL, Opekun AR, Gilger MA, Estes MK, Crawford SE, Neill FH, Graham DY. Norwalk virus shedding after experimental human infection. Emerg Infect Dis 2008; 14:1553-7. [PMID: 18826818 PMCID: PMC2609865 DOI: 10.3201/eid1410.080117] [Citation(s) in RCA: 517] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Noroviruses are shed in feces up to 8 weeks after infection. Noroviruses are the most common cause of viral gastroenteritis in the United States. To determine the magnitude and duration of virus shedding in feces, we evaluated persons who had been experimentally infected with Norwalk virus. Of 16 persons, clinical gastroenteritis (watery diarrhea and/or vomiting) developed in 11; symptomatic illness lasted 1–2 days. Virus shedding was first detected by reverse transcription–PCR (RT-PCR) 18 hours after participant inoculation and lasted a median of 28 days after inoculation (range 13–56 days). The median peak amount of virus shedding was 95 × 109 (range 0.5–1,640 ×109) genomic copies/g feces as measured by quantitative RT-PCR. Virus shedding was first detected by antigen ELISA ≈33 hours (median 42 hours) after inoculation and lasted 10 days (median 7 days) after inoculation. Understanding of the relevance of prolonged fecal norovirus excretion must await the development of sensitive methods to measure virus infectivity.
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Affiliation(s)
- Robert L Atmar
- Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, USA.
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23
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Recovery of infectious virus by transfection of in vitro-generated RNA from tulane calicivirus cDNA. J Virol 2008; 82:11429-36. [PMID: 18787011 DOI: 10.1128/jvi.00696-08] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Tulane virus (TV) is a newly reported calicivirus that was isolated from stool samples of captive rhesus macaques from the Tulane National Primate Research Center (TNPRC). The virus has been cultivated successfully in LLC-MK2 rhesus monkey kidney cells. Its complete genomic sequence suggests that TV represents a new genus and is evolutionarily more closely related to Norovirus than to any other genus of Caliciviridae. In this study, we demonstrated that RNA transcripts made in vitro from the full-length genomic cDNA of TV were infectious upon transfection into permissive LLC-MK2 cells. The recombinant virus exhibited plaque morphologies and growth kinetics similar to those of the wild-type virus in this cell line. Capping was required for TV RNA infectivity. Although a subgenomic RNA has been detected in TV-transfected cells, a separate subgenomic RNA transcript was not required for the initial transfection to establish the replication. Transfection of truncated RNA lacking open reading frame 2 (ORF2) and ORF3 or TV-norovirus chimeric RNA resulted in abortive replication without the production of infectious progeny viruses, indicating that both ORFs are essential for the replication of TV. A heterologous insertion at the 5' end of the genome also hampered viral replication, suggesting that an authentic 5' end of the genome is critical for replication. The availability of the complete genomic sequence and the reverse genetics system described herein make TV a valuable model for studying calicivirus pathogenesis and replication.
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24
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Simmonds P, Karakasiliotis I, Bailey D, Chaudhry Y, Evans DJ, Goodfellow IG. Bioinformatic and functional analysis of RNA secondary structure elements among different genera of human and animal caliciviruses. Nucleic Acids Res 2008; 36:2530-46. [PMID: 18319285 PMCID: PMC2377429 DOI: 10.1093/nar/gkn096] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 02/02/2008] [Accepted: 02/18/2008] [Indexed: 11/14/2022] Open
Abstract
The mechanism and role of RNA structure elements in the replication and translation of Caliciviridae remains poorly understood. Several algorithmically independent methods were used to predict secondary structures within the Norovirus, Sapovirus, Vesivirus and Lagovirus genera. All showed profound suppression of synonymous site variability (SSSV) at genomic 5' ends and the start of the sub-genomic (sg) transcript, consistent with evolutionary constraints from underlying RNA structure. A newly developed thermodynamic scanning method predicted RNA folding mapping precisely to regions of SSSV and at the genomic 3' end. These regions contained several evolutionarily conserved RNA secondary structures, of variable size and positions. However, all caliciviruses contained 3' terminal hairpins, and stem-loops in the anti-genomic strand invariably six bases upstream of the sg transcript, indicating putative roles as sg promoters. Using the murine norovirus (MNV) reverse-genetics system, disruption of 5' end stem-loops produced approximately 15- to 20-fold infectivity reductions, while disruption of the RNA structure in the sg promoter region and at the 3' end entirely destroyed replication ability. Restoration of infectivity by repair mutations in the sg promoter region confirmed a functional role for the RNA secondary structure, not the sequence. This study provides comprehensive bioinformatic resources for future functional studies of MNV and other caliciviruses.
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Affiliation(s)
- Peter Simmonds
- Centre for Infectious Diseases, University of Edinburgh, Summerhall, Edinburgh, EH9 1QH, UK.
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25
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Guix S, Asanaka M, Katayama K, Crawford SE, Neill FH, Atmar RL, Estes MK. Norwalk virus RNA is infectious in mammalian cells. J Virol 2007; 81:12238-48. [PMID: 17855551 PMCID: PMC2168986 DOI: 10.1128/jvi.01489-07] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 08/30/2007] [Indexed: 12/25/2022] Open
Abstract
Human noroviruses are positive-sense RNA viruses and are the leading cause of epidemic acute viral gastroenteritis in developed countries. The absence of an in vitro cell culture model for human norovirus infection has limited the development of effective antivirals and vaccines. Human histo-blood group antigens have been regarded as receptors for norovirus infection, and expression of the alpha(1,2) fucosyltransferase gene (FUT2) responsible for the secretor phenotype is required for susceptibility to Norwalk virus (NV) infection. We report for the first time that transfection of NV RNA, isolated from stool samples from human volunteers, into human hepatoma Huh-7 cells leads to viral replication, with expression of viral antigens, RNA replication, and release of viral particles into the medium. Prior treatment of the RNA with proteinase K completely abolishes RNA infectivity, suggesting a key role of an RNA-protein complex. Although overexpression of the human FUT2 gene enhances virus binding to cells, it is not sufficient to allow a complete viral infection, and viral spread from NV-transfected cells to naïve cells does not occur. Finally, no differences in NV RNA replication are observed between Huh-7 and Huh-7.5.1 cells, which contain an inactivating mutation in retinoic acid-inducible gene I (RIG-I), suggesting that the RIG-I pathway does not play a role in limiting NV replication. Our results strongly suggest that the block(s) to NV replication in vitro is at the stage of receptor and/or coreceptor binding and/or uncoating, either because cells lack some specific factor or activation of cellular antiviral responses independent of RIG-I inhibits virus replication.
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Affiliation(s)
- Susana Guix
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza BCM-385, Houston, TX 77030, USA
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26
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Chaudhry Y, Skinner MA, Goodfellow IG. Recovery of genetically defined murine norovirus in tissue culture by using a fowlpox virus expressing T7 RNA polymerase. J Gen Virol 2007; 88:2091-2100. [PMID: 17622609 PMCID: PMC2884977 DOI: 10.1099/vir.0.82940-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Despite the significant disease burden caused by human norovirus infection, an efficient tissue-culture system for these viruses remains elusive. Murine norovirus (MNV) is an ideal surrogate for the study of norovirus biology, as the virus replicates efficiently in tissue culture and a low-cost animal model is readily available. In this report, a reverse-genetics system for MNV is described, using a fowlpox virus (FWPV) recombinant expressing T7 RNA polymerase to recover genetically defined MNV in tissue culture for the first time. These studies demonstrated that approaches that have proved successful for other members of the family Caliciviridae failed to lead to recovery of MNV. This was due to our observation that vaccinia virus infection had a negative effect on MNV replication. In contrast, FWPV infection had no deleterious effect and allowed the recovery of infectious MNV from cells previously transfected with MNV cDNA constructs. These studies also indicated that the nature of the 3′-terminal nucleotide is critical for efficient virus recovery and that inclusion of a hepatitis delta virus ribozyme at the 3′ end can increase the efficiency with which virus is recovered. This system now allows the recovery of genetically defined noroviruses and will facilitate the analysis of the effects of genetic variation on norovirus pathogenesis.
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Affiliation(s)
- Yasmin Chaudhry
- Calicivirus Research Group, Department of Virology, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Michael A. Skinner
- Vaccine Vector Group, Department of Virology, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
| | - Ian G. Goodfellow
- Calicivirus Research Group, Department of Virology, Faculty of Medicine, Imperial College London, St Mary's Campus, Norfolk Place, London W2 1PG, UK
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27
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Wobus CE, Thackray LB, Virgin HW. Murine norovirus: a model system to study norovirus biology and pathogenesis. J Virol 2007; 80:5104-12. [PMID: 16698991 PMCID: PMC1472167 DOI: 10.1128/jvi.02346-05] [Citation(s) in RCA: 447] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Christiane E Wobus
- Department of Pathology and Immunology, Box 8118, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA
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28
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Kearney K, Menton J, Morgan JG. Carlow virus, a 2002 GII.4 variant Norovirus strain from Ireland. Virol J 2007; 4:61. [PMID: 17567897 PMCID: PMC1913912 DOI: 10.1186/1743-422x-4-61] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 06/13/2007] [Indexed: 12/19/2022] Open
Abstract
Background Noroviruses are the leading cause of infectious non-bacterial gastroenteritis in Ireland (population 4 million). Due to the number of outbreaks, its massive impact on the Irish health service and its seasonality, Norovirus has gained public notoriety as The Winter Vomiting Bug. The increase in cases in Ireland in the 2002–2003 season coincided with the emergence of two new Genogroup II genotype 4 variant clusters of Norovirus worldwide. Results Little research has been done on the epidemiology or molecular biology of Norovirus strains in Ireland. In an effort to combat this discrepancy, we cloned a full length human norovirus genome as a cDNA clone (J3) which can produce full length transcripts in vitro. A polymerase mutant cDNA clone (X1), in addition to a sub genomic cDNA clone (1A) were produced for use in future work. Carlow virus (Hu/NoV/GII/Carlow/2002/Ire) genome is 7559 nts in length, excluding the 3-end poly A tail and represents the first Norovirus strain from Ireland to be sequenced. Conclusion Carlow virus is a member of the Farmington Hills variant cluster of Genogroup II genotype 4 noroviruses.
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Affiliation(s)
- Karen Kearney
- Lab 439, Department of Microbiology, University College Cork, College Road, Cork, Ireland
| | - John Menton
- Lab 439, Department of Microbiology, University College Cork, College Road, Cork, Ireland
| | - John G Morgan
- Lab 439, Department of Microbiology, University College Cork, College Road, Cork, Ireland
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29
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Oka T, Yamamoto M, Yokoyama M, Ogawa S, Hansman GS, Katayama K, Miyashita K, Takagi H, Tohya Y, Sato H, Takeda N. Highly conserved configuration of catalytic amino acid residues among calicivirus-encoded proteases. J Virol 2007; 81:6798-806. [PMID: 17459935 PMCID: PMC1933329 DOI: 10.1128/jvi.02840-06] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
A common feature of caliciviruses is the proteolytic processing of the viral polyprotein catalyzed by the viral 3C-like protease encoded in open reading frame 1 (ORF1). Here we report the identification and structural characterization of the protease domains and amino acid residues in sapovirus (SaV) and feline calicivirus (FCV). The in vitro expression and processing of a panel of truncated ORF1 polyproteins and corresponding mutant forms showed that the functional protease domain is 146 amino acids (aa) in SaV and 154 aa in FCV. Site-directed mutagenesis of the protease domains identified four amino acid residues essential to protease activities: H(31), E(52), C(116), and H(131) in SaV and H(39), E(60), C(122), and H(137) in FCV. A computer-assisted structural analysis showed that despite high levels of diversity in the primary structures of the protease domains in the family Caliciviridae, the configurations of the H, E, C, and H residues are highly conserved, with these residues positioned closely along the inner surface of the potential binding cleft for the substrate. These results strongly suggest that the H, E, C, and H residues are involved in the formation of a conserved catalytic surface of the SaV and FCV 3C-like proteases.
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Affiliation(s)
- Tomoichiro Oka
- Department of Virology II, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashi-murayama, Tokyo 208-0011, Japan.
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30
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Fullerton SWB, Blaschke M, Coutard B, Gebhardt J, Gorbalenya A, Canard B, Tucker PA, Rohayem J. Structural and functional characterization of sapovirus RNA-dependent RNA polymerase. J Virol 2006; 81:1858-71. [PMID: 17121797 PMCID: PMC1797576 DOI: 10.1128/jvi.01462-06] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Sapoviruses are one of the major agents of acute gastroenteritis in childhood. They form a tight genetic cluster (genus) in the Caliciviridae family that regroups both animal and human pathogenic strains. No permissive tissue culture has been developed for human sapovirus, limiting its characterization to surrogate systems. We report here on the first extensive characterization of the key enzyme of replication, the RNA-dependent RNA polymerase (RdRp) associated with the 3D(pol)-like protein. Enzymatically active sapovirus 3D(pol) and its defective mutant were expressed in Escherichia coli and purified. The overall structure of the sapovirus 3D(pol) was determined by X-ray crystallography to 2.32-A resolution. It revealed a right hand fold typical for template-dependent polynucleotide polymerases. The carboxyl terminus is located within the active site cleft, as observed in the RdRp of some (norovirus) but not other (lagovirus) caliciviruses. Sapovirus 3D(pol) prefers Mn(2+) over Mg(2+) but may utilize either as a cofactor in vitro. In a synthetic RNA template-dependent reaction, sapovirus 3D(pol) synthesizes a double-stranded RNA or labels the template 3' terminus by terminal transferase activity. Initiation of RNA synthesis occurs de novo on heteropolymeric templates or in a primer-dependent manner on polyadenylated templates. Strikingly, this mode of initiation of RNA synthesis was also described for norovirus, but not for lagovirus, suggesting structural and functional homologies in the RNA-dependent RNA polymerase of human pathogenic caliciviruses. This first experimental evidence makes sapovirus 3D(pol) an attractive target for developing drugs to control calicivirus infection in humans.
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