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Su L, Huang W, Neill FH, Estes MK, Atmar RL, Palzkill T. Mapping human norovirus antigens during infection reveals the breadth of the humoral immune response. NPJ Vaccines 2023; 8:87. [PMID: 37280322 DOI: 10.1038/s41541-023-00683-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 05/25/2023] [Indexed: 06/08/2023] Open
Abstract
Human noroviruses (HuNoV) are the leading cause of acute gastroenteritis worldwide. The humoral immune response plays an important role in clearing HuNoV infections and elucidating the antigenic landscape of HuNoV during an infection can shed light on antibody targets to inform vaccine design. Here, we utilized Jun-Fos-assisted phage display of a HuNoV genogroup GI.1 genomic library and deep sequencing to simultaneously map the epitopes of serum antibodies of six individuals infected with GI.1 HuNoV. We found both unique and common epitopes that were widely distributed among both nonstructural proteins and the major capsid protein. Recurring epitope profiles suggest immunodominant antibody footprints among these individuals. Analysis of sera collected longitudinally from three individuals showed the presence of existing epitopes in the pre-infection sera, suggesting these individuals had prior HuNoV infections. Nevertheless, newly recognized epitopes surfaced seven days post-infection. These new epitope signals persisted by 180 days post-infection along with the pre-infection epitopes, suggesting a persistent production of antibodies recognizing epitopes from previous and new infections. Lastly, analysis of a GII.4 genotype genomic phage display library with sera of three persons infected with GII.4 virus revealed epitopes that overlapped with those identified in GI.1 affinity selections, suggesting the presence of GI.1/GII.4 cross-reactive antibodies. The results demonstrate that genomic phage display coupled with deep sequencing can characterize HuNoV antigenic landscapes from complex polyclonal human sera to reveal the timing and breadth of the human humoral immune response to infection.
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Affiliation(s)
- Lynn Su
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Wanzhi Huang
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Frederick H Neill
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Mary K Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Robert L Atmar
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Timothy Palzkill
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
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2
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Van Dycke J, Puxeddu M, La Regina G, Mastrangelo E, Tarantino D, Rymenants J, Sebastiani J, Nalli M, Matthijnssens J, Neyts J, Silvestri R, Rocha-Pereira J. Discovery of a Novel Class of Norovirus Inhibitors with High Barrier of Resistance. Pharmaceuticals (Basel) 2021; 14:ph14101006. [PMID: 34681230 PMCID: PMC8537218 DOI: 10.3390/ph14101006] [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: 08/23/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 11/16/2022] Open
Abstract
Human noroviruses (HuNoVs) are the most common cause of viral gastroenteritis resulting in ~219,000 deaths annually and a societal cost of ~USD60 billion. There are no antivirals or vaccines available to treat and/or prevent HuNoV. In this study, we performed a large-scale phenotypical antiviral screening using the mouse norovirus (MNV), which included ~1000 drug-like small molecules from the Drug Design and Synthesis Centre (Sapienza University, Rome). Compound 3-((3,5-dimethylphenyl)sulfonyl)-5-chloroindole-N-(phenylmethanol-4-yl)-2.carboxamide (compound 1) was identified as an inhibitor of MNV replication with an EC50 of 0.5 ± 0.1 µM. A series of 10 analogs were synthesized of which compound 6 showed an improved potency/selectivity (EC50 0.2 ± 0.1 µM) against MNV; good activity was also observed against the HuNoV GI replicon (EC50 1.2 ± 0.6 µM). Time-of-drug-addition studies revealed that analog 6 acts at a time point that coincides with the onset of viral RNA replication. After six months of selective pressure, two compound 6res variants were independently selected, both harboring one mutation in VPg and three mutations in the RdRp. After reverse engineering S131T and Y154F as single mutations into the MNV backbone, we did not find a markedly compound 6res phenotype. In this study, we present a class of novel norovirus inhibitors with a high barrier to resistance and in vitro antiviral activity.
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Affiliation(s)
- Jana Van Dycke
- Laboratory of Virology & Chemotherapy, Department of Microbiology, Immunology & Transplantation, Rega Institute for Medical Research, KU Leuven—University of Leuven, 3000 Leuven, Belgium; (J.V.D.); (J.R.); (J.N.)
| | - Michela Puxeddu
- Laboratory Affiliated with the Institute Pasteur Italy—Cenci Bolognetti Foundation, Department of Drug Chemistry and Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (G.L.R.); (J.S.); (M.N.); (R.S.)
| | - Giuseppe La Regina
- Laboratory Affiliated with the Institute Pasteur Italy—Cenci Bolognetti Foundation, Department of Drug Chemistry and Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (G.L.R.); (J.S.); (M.N.); (R.S.)
| | - Eloise Mastrangelo
- CNR—Biophysics Institute, Università degli Studi di Milano, 20122 Milano, Italy; (E.M.); (D.T.)
| | - Delia Tarantino
- CNR—Biophysics Institute, Università degli Studi di Milano, 20122 Milano, Italy; (E.M.); (D.T.)
| | - Jasper Rymenants
- Laboratory of Virology & Chemotherapy, Department of Microbiology, Immunology & Transplantation, Rega Institute for Medical Research, KU Leuven—University of Leuven, 3000 Leuven, Belgium; (J.V.D.); (J.R.); (J.N.)
| | - Jessica Sebastiani
- Laboratory Affiliated with the Institute Pasteur Italy—Cenci Bolognetti Foundation, Department of Drug Chemistry and Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (G.L.R.); (J.S.); (M.N.); (R.S.)
| | - Marianna Nalli
- Laboratory Affiliated with the Institute Pasteur Italy—Cenci Bolognetti Foundation, Department of Drug Chemistry and Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (G.L.R.); (J.S.); (M.N.); (R.S.)
| | - Jelle Matthijnssens
- Laboratory of Clinical and Epidemiological Virology, Department of Microbiology, Immunology & Transplantation, Rega Institute for Medical Research, KU Leuven—University of Leuven, 3000 Leuven, Belgium;
| | - Johan Neyts
- Laboratory of Virology & Chemotherapy, Department of Microbiology, Immunology & Transplantation, Rega Institute for Medical Research, KU Leuven—University of Leuven, 3000 Leuven, Belgium; (J.V.D.); (J.R.); (J.N.)
| | - Romano Silvestri
- Laboratory Affiliated with the Institute Pasteur Italy—Cenci Bolognetti Foundation, Department of Drug Chemistry and Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.P.); (G.L.R.); (J.S.); (M.N.); (R.S.)
| | - Joana Rocha-Pereira
- Laboratory of Virology & Chemotherapy, Department of Microbiology, Immunology & Transplantation, Rega Institute for Medical Research, KU Leuven—University of Leuven, 3000 Leuven, Belgium; (J.V.D.); (J.R.); (J.N.)
- Correspondence: ; Tel.: +32-16-37-90-20
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3
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Eruera AR, McSweeney AM, McKenzie-Goldsmith GM, Ward VK. Protein Nucleotidylylation in +ssRNA Viruses. Viruses 2021; 13:1549. [PMID: 34452414 PMCID: PMC8402628 DOI: 10.3390/v13081549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/30/2021] [Accepted: 08/02/2021] [Indexed: 12/22/2022] Open
Abstract
Nucleotidylylation is a post-transcriptional modification important for replication in the picornavirus supergroup of RNA viruses, including members of the Caliciviridae, Coronaviridae, Picornaviridae and Potyviridae virus families. This modification occurs when the RNA-dependent RNA polymerase (RdRp) attaches one or more nucleotides to a target protein through a nucleotidyl-transferase reaction. The most characterized nucleotidylylation target is VPg (viral protein genome-linked), a protein linked to the 5' end of the genome in Caliciviridae, Picornaviridae and Potyviridae. The nucleotidylylation of VPg by RdRp is a critical step for the VPg protein to act as a primer for genome replication and, in Caliciviridae and Potyviridae, for the initiation of translation. In contrast, Coronaviridae do not express a VPg protein, but the nucleotidylylation of proteins involved in replication initiation is critical for genome replication. Furthermore, the RdRp proteins of the viruses that perform nucleotidylylation are themselves nucleotidylylated, and in the case of coronavirus, this has been shown to be essential for viral replication. This review focuses on nucleotidylylation within the picornavirus supergroup of viruses, including the proteins that are modified, what is known about the nucleotidylylation process and the roles that these modifications have in the viral life cycle.
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Affiliation(s)
| | | | | | - Vernon K. Ward
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, PO Box 56, Dunedin 9054, New Zealand; (A.-R.E.); (A.M.M.); (G.M.M.-G.)
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4
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McSweeney AM, Young VL, Ward VK. Norovirus VPg Binds RNA through a Conserved N-Terminal K/R Basic Patch. Viruses 2021; 13:v13071282. [PMID: 34209211 PMCID: PMC8310136 DOI: 10.3390/v13071282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 11/17/2022] Open
Abstract
The viral protein genome-linked (VPg) of noroviruses is a multi-functional protein that participates in essential roles during the viral replication cycle. Predictive analyses indicate that murine norovirus (MNV) VPg contains a disordered N-terminal region with RNA binding potential. VPg proteins were expressed with an N-terminal spidroin fusion protein in insect cells and the interaction with RNA investigated by electrophoretic mobility shift assays (EMSA) against a series of RNA probes (pentaprobes) representing all possible five nucleotide combinations. MNV VPg and human norovirus (HuNV) VPg proteins were directly bound to RNA in a non-specific manner. To identify amino acids involved in binding to RNA, all basic (K/R) residues in the first 12 amino acids of MNV VPg were mutated to alanine. Removal of the K/R amino acids eliminated RNA binding and is consistent with a K/R basic patch RNA binding motif within the disordered N-terminal region of norovirus VPgs. Finally, we show that mutation of the K/R basic patch required for RNA binding eliminates the ability of MNV VPg to induce a G0/G1 cell cycle arrest.
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Campillay-Véliz CP, Carvajal JJ, Avellaneda AM, Escobar D, Covián C, Kalergis AM, Lay MK. Human Norovirus Proteins: Implications in the Replicative Cycle, Pathogenesis, and the Host Immune Response. Front Immunol 2020; 11:961. [PMID: 32612600 PMCID: PMC7308418 DOI: 10.3389/fimmu.2020.00961] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/23/2020] [Indexed: 12/19/2022] Open
Abstract
Human noroviruses (HuNoVs) are the cause of more than 95% of epidemic non-bacterial gastroenteritis worldwide, with some lethal cases. These viral agents affect people of all ages. However, young children and older adults are the highest-risk groups, being affected with the greatest rate of hospitalizations and morbidity cases. HuNoV structural proteins, especially VP1, have been studied extensively. In contrast, the functions of the non-structural proteins of the virus have been undescribed in depth. Studies on HuNoV non-structural proteins have mostly been made by expressing them individually in in vitro cultures, providing insights of their functions and the role that they play in HuNoV replication and pathogenesis. This review examines exhaustively the functions of both HuNoV structural and non-structural proteins and their possible role within the viral replicative cycle and the pathogenesis of the virus. It also highlights recent findings regarding the host's innate and adaptive immune responses against HuNoV, which are of great relevance for diagnostics and vaccine development so as to prevent infections caused by these fastidious viruses.
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Affiliation(s)
- Claudia P Campillay-Véliz
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Jonatan J Carvajal
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Andrea M Avellaneda
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Darling Escobar
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Camila Covián
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Margarita K Lay
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad de Chile, Santiago, Chile
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6
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Caliciviral protein-based artificial translational activator for mammalian gene circuits with RNA-only delivery. Nat Commun 2020; 11:1297. [PMID: 32157083 PMCID: PMC7064597 DOI: 10.1038/s41467-020-15061-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/12/2020] [Indexed: 12/13/2022] Open
Abstract
Synthetic RNA-based gene circuits enable sophisticated gene regulation without the risk of insertional mutagenesis. While various RNA binding proteins have been used for translational repression in gene circuits, the direct translational activation of synthetic mRNAs has not been achieved. Here we develop Caliciviral VPg-based Translational activator (CaVT), which activates the translation of synthetic mRNAs without the canonical 5'-cap. The level of translation can be modulated by changing the locations, sequences, and modified nucleosides of CaVT-binding motifs in the target mRNAs, enabling the simultaneous translational activation and repression of different mRNAs with RNA-only delivery. We demonstrate the efficient regulation of apoptosis and genome editing by tuning translation levels with CaVT. In addition, we design programmable CaVT that responds to endogenous microRNAs or small molecules, achieving both cell-state-specific and conditional translational activation from synthetic mRNAs. CaVT will become an important tool in synthetic biology for both biological studies and future therapeutic applications.
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7
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Smertina E, Urakova N, Strive T, Frese M. Calicivirus RNA-Dependent RNA Polymerases: Evolution, Structure, Protein Dynamics, and Function. Front Microbiol 2019; 10:1280. [PMID: 31244803 PMCID: PMC6563846 DOI: 10.3389/fmicb.2019.01280] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 05/22/2019] [Indexed: 12/11/2022] Open
Abstract
The Caliciviridae are viruses with a positive-sense, single-stranded RNA genome that is packaged into an icosahedral, environmentally stable protein capsid. The family contains five genera (Norovirus, Nebovirus, Sapovirus, Lagovirus, and Vesivirus) that infect vertebrates including amphibians, reptiles, birds, and mammals. The RNA-dependent RNA polymerase (RdRp) replicates the genome of RNA viruses and can speed up evolution due to its error-prone nature. Studying calicivirus RdRps in the context of genuine virus replication is often hampered by a lack of suitable model systems. Enteric caliciviruses and RHDV in particular are notoriously difficult to propagate in cell culture; therefore, molecular studies of replication mechanisms are challenging. Nevertheless, research on recombinant proteins has revealed several unexpected characteristics of calicivirus RdRps. For example, the RdRps of RHDV and related lagoviruses possess the ability to expose a hydrophobic motif, to rearrange Golgi membranes, and to copy RNA at unusually high temperatures. This review is focused on the structural dynamics, biochemical properties, kinetics, and putative interaction partners of these RdRps. In addition, we discuss the possible existence of a conserved but as yet undescribed structural element that is shared amongst the RdRps of all caliciviruses.
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Affiliation(s)
- Elena Smertina
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Nadya Urakova
- Department of Entomology, Pennsylvania State University, University Park, PA, United States
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organisation, Health and Biosecurity, Canberra, ACT, Australia
- Invasive Animals Cooperative Research Centre, University of Canberra, Canberra, ACT, Australia
| | - Michael Frese
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
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Emmott E, de Rougemont A, Hosmillo M, Lu J, Fitzmaurice T, Haas J, Goodfellow I. Polyprotein processing and intermolecular interactions within the viral replication complex spatially and temporally control norovirus protease activity. J Biol Chem 2019; 294:4259-4271. [PMID: 30647130 PMCID: PMC6422069 DOI: 10.1074/jbc.ra118.006780] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Indexed: 11/26/2022] Open
Abstract
Norovirus infections are a major cause of acute viral gastroenteritis and a significant burden on global human health. A vital process for norovirus replication is the processing of the nonstructural polyprotein by a viral protease into the viral components required to form the viral replication complex. This cleavage occurs at different rates, resulting in the accumulation of stable precursor forms. Here, we characterized how precursor forms of the norovirus protease accumulate during infection. Using stable forms of the protease precursors, we demonstrated that all of them are proteolytically active in vitro, but that when expressed in cells, their activities are determined by both substrate and protease localization. Although all precursors could cleave a replication complex-associated substrate, only a subset of precursors lacking the NS4 protein were capable of efficiently cleaving a cytoplasmic substrate. By mapping the full range of protein-protein interactions among murine and human norovirus proteins with the LUMIER assay, we uncovered conserved interactions between replication complex members that modify the localization of a protease precursor subset. Finally, we demonstrate that fusion to the membrane-bound replication complex components permits efficient cleavage of a fused substrate when active polyprotein-derived protease is provided in trans These findings offer a model for how norovirus can regulate the timing of substrate cleavage throughout the replication cycle. Because the norovirus protease represents a key target in antiviral therapies, an improved understanding of its function and regulation, as well as identification of interactions among the other nonstructural proteins, offers new avenues for antiviral drug design.
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Affiliation(s)
- Edward Emmott
- From the Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 0QQ, United Kingdom,
| | - Alexis de Rougemont
- the National Reference Centre for Gastroenteritis Viruses, Labology of Biology and Pathology, University Hospital Dijon Bourgogne, Dijon 21700, France
- the AgroSup Dijon, PAM UMR A 02.102 Bourgogne Franche-Comte University, Dijon 21000, France, and
| | - Myra Hosmillo
- From the Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 0QQ, United Kingdom
| | - Jia Lu
- From the Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 0QQ, United Kingdom
| | - Timothy Fitzmaurice
- From the Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 0QQ, United Kingdom
| | - Jürgen Haas
- the Division of Infection and Pathway Medicine, University of Edinburgh Medical School, Edinburgh EH16 4SB, United Kingdom
| | - Ian Goodfellow
- From the Division of Virology, Department of Pathology, University of Cambridge, Addenbrookes Hospital, Hills Road, Cambridge CB2 0QQ, United Kingdom,
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Cell Cycle Arrest is a Conserved Function of Norovirus VPg Proteins. Viruses 2019; 11:v11030217. [PMID: 30836641 PMCID: PMC6466040 DOI: 10.3390/v11030217] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/26/2019] [Accepted: 02/27/2019] [Indexed: 12/04/2022] Open
Abstract
Murine norovirus (MNV) viral protein genome-linked (VPg) manipulates the cell cycle to induce a G0/G1 arrest and gain a beneficial replication environment. All viruses of the norovirus genus encode a VPg protein; however, it is unknown if the G0/G1 arrest induced by MNV VPg is conserved in other members of the genus. RNA transcripts encoding a representative viral VPg from five norovirus genogroups were transfected into RAW-Blue murine macrophages, and the percentage of cells in each phase of the cell cycle was determined. A G0/G1 cell cycle arrest was observed for all norovirus VPg proteins tested, and in the wider Caliciviridae family the arrest was also conserved in rabbit hemorrhagic disease virus (RHDV) VPg and human sapovirus (HuSV) VPg. Truncation of MNV VPg shows that the first 62 amino acids are sufficient for a cell cycle arrest, and alignment of VPg sequences revealed a conserved motif in the N-terminal region of VPg. Analysis of VPg constructs with single N-terminal region point mutations, or exchange of N-terminal regions between VPg proteins, confirmed the importance of the N-terminal region for cell cycle arrest. These results provide evidence that G0/G1 cell cycle arrest is a conserved function of norovirus VPg proteins that involves the N-terminal region of these proteins.
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10
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Structure and Function of Caliciviral RNA Polymerases. Viruses 2017; 9:v9110329. [PMID: 29113097 PMCID: PMC5707536 DOI: 10.3390/v9110329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/26/2017] [Accepted: 11/02/2017] [Indexed: 11/16/2022] Open
Abstract
Caliciviruses are a leading agent of human and animal gastroenteritis and respiratory tract infections, which are growing concerns in immunocompromised individuals. However, no vaccines or therapeutics are yet available. Since the rapid rate of genetic evolution of caliciviruses is mainly due to the error-prone nature of RNA-dependent RNA polymerase (RdRp), this article focuses on recent studies of the structures and functions of RdRp from caliciviruses. It also provides recent advances in the interactions of RdRp with virion protein genome-linked (VPg) and RNA and the structural and functional features of its precursor.
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11
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Han KR, Alhatlani BY, Cho S, Lee JH, Hosmillo M, Goodfellow IG, Kim KH, Yang JM. Identification of amino acids within norovirus polymerase involved in RNA binding and viral replication. J Gen Virol 2017. [PMID: 28640742 DOI: 10.1099/jgv.0.000826] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Until recently, molecular studies on human norovirus (HuNoV), a major causative agent of gastroenteritis, have been hampered by the lack of an efficient cell culture system. Murine norovirus-1 (MNV-1) has served as a surrogate model system for norovirus research, due to the availability of robust cell culture systems and reverse genetics. To identify amino acids involved in RNA synthesis by the viral RNA-dependent RNA polymerase (NS7), we constructed NS7 mutants in which basic amino acids surrounding the catalytic site were substituted with alanine. Electrophoretic mobility shift assay revealed that these residues are important for RNA binding, particularly R396. Furthermore, in vitro RNA synthesis and reverse genetics were used to identify conserved amino acids essential for RNA synthesis and viral replication. These results provide additional functional insights into highly conserved amino acids in NS7 and provide potential methods of rational attenuation of norovirus replication.
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Affiliation(s)
- Kang Rok Han
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea
- Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea
| | - Bader Y Alhatlani
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Sunyoung Cho
- Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea
| | - Ji-Hye Lee
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea
| | - Myra Hosmillo
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Ian G Goodfellow
- Division of Virology, Department of Pathology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Kyung Hyun Kim
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 339-700, Republic of Korea
| | - Jai Myung Yang
- Department of Life Science, Sogang University, Seoul 121-742, Republic of Korea
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