1
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Norovirus 3C-Like protease antagonizes interferon-β production by cleaving NEMO. Virology 2022; 571:12-20. [DOI: 10.1016/j.virol.2022.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/06/2022] [Accepted: 04/07/2022] [Indexed: 11/23/2022]
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2
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Zhao B, Hu L, Song Y, Patil K, Ramani S, Atmar RL, Estes MK, Prasad BVV. Norovirus Protease Structure and Antivirals Development. Viruses 2021; 13:v13102069. [PMID: 34696498 PMCID: PMC8537771 DOI: 10.3390/v13102069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/06/2021] [Accepted: 10/09/2021] [Indexed: 11/30/2022] Open
Abstract
Human norovirus (HuNoV) infection is a global health and economic burden. Currently, there are no licensed HuNoV vaccines or antiviral drugs available. The protease encoded by the HuNoV genome plays a critical role in virus replication by cleaving the polyprotein and is an excellent target for developing small-molecule inhibitors. The current strategy for developing HuNoV protease inhibitors is by targeting the enzyme’s active site and designing inhibitors that bind to the substrate-binding pockets located near the active site. However, subtle differential conformational flexibility in response to the different substrates in the polyprotein and structural differences in the active site and substrate-binding pockets across different genogroups, hamper the development of effective broad-spectrum inhibitors. A comparative analysis of the available HuNoV protease structures may provide valuable insight for identifying novel strategies for the design and development of such inhibitors. The goal of this review is to provide such analysis together with an overview of the current status of the design and development of HuNoV protease inhibitors.
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Affiliation(s)
- Boyang Zhao
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (K.P.); (S.R.); (R.L.A.); (M.K.E.)
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Yongcheng Song
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX 77030, USA;
| | - Ketki Patil
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (K.P.); (S.R.); (R.L.A.); (M.K.E.)
| | - Sasirekha Ramani
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (K.P.); (S.R.); (R.L.A.); (M.K.E.)
| | - Robert L. Atmar
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (K.P.); (S.R.); (R.L.A.); (M.K.E.)
- Department of Medicine, 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; (B.Z.); (K.P.); (S.R.); (R.L.A.); (M.K.E.)
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - B. V. Venkataram Prasad
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA; (B.Z.); (K.P.); (S.R.); (R.L.A.); (M.K.E.)
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA;
- Correspondence: ; Tel.: +1-713-798-5686
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3
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Pankovics P, Boros Á, László Z, Szekeres S, Földvári G, Altan E, Delwart E, Reuter G. Genome characterization, prevalence and tissue distribution of astrovirus, hepevirus and norovirus among wild and laboratory rats (Rattus norvegicus) and mice (Mus musculus) in Hungary. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2021; 93:104942. [PMID: 34044191 DOI: 10.1016/j.meegid.2021.104942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 12/17/2022]
Abstract
Rodents including rats are reservoir of several pathogens capable of affecting human health. In this study, faecal and different organ specimens from free-living Norway rats (Rattus norvegicus) (N = 18) and faecal samples from laboratory rodents (rats N = 21 and mice N = 20) collected from different geographic areas in Hungary between 2017 and 2020 were investigated by viral metagenomics and conventional RT-PCR methods. The complete genome of three different RNA viruses, rat astrovirus, rat norovirus and rat hepevirus were characterized and analysed in detail. Rat norovirus was detected in faecal (17.6%, 3/17) and kidney (7.1%, 1/14) samples; rat astrovirus in faecal (23.5%, 4/17) and spleen (13.3%, 2/15) samples, and rat hepevirus in 43% to 67% the faecal, liver, kidney, lung, heart, muscle, brain and blood samples from Norway rats, respectively. Rat norovirus was also identifiable in 5% (1/21) of laboratory rats and rat astrovirus in 40% (8/20) of faecal samples from laboratory mice. Co-infections were found in 28% (5/18) wild Norway rats. The highest RNA viral load of astrovirus (1.81 × 108 copy/g) and norovirus (3.49 × 107 copy/g) were measured in faecal samples; while the highest RNA viral load of hepevirus (1.16 × 109 copy/g) was found in liver samples of Norway rats, respectively. This study confirms the wide geographic distribution and high prevalence of astrovirus, norovirus and hepevirus among wild rats in Hungary with confirmation of different organ involvement of as well as the detection of norovirus and astrovirus in laboratory rats and mice, respectively. This finding further strengthens the role of rodents in the spread of viral pathogens especially infecting human.
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Affiliation(s)
- Péter Pankovics
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary.
| | - Ákos Boros
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Zoltán László
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Sándor Szekeres
- Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, Hungary
| | - Gábor Földvári
- Institute of Evolution, Centre for Ecological Research, Budapest, Hungary
| | - Eda Altan
- Vitalant Research Institute, San Francisco, CA, USA
| | - Eric Delwart
- Vitalant Research Institute, San Francisco, CA, USA; University of California, San Francisco, CA, USA
| | - Gábor Reuter
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
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4
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Zheng Z, Li Y, Zhang M, Liu Y, Fu M, Gong S, Hu Q. Human Norovirus NTPase Antagonizes Interferon-β Production by Interacting With IkB Kinase ε. Front Microbiol 2021; 12:687933. [PMID: 34335514 PMCID: PMC8319745 DOI: 10.3389/fmicb.2021.687933] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/17/2021] [Indexed: 12/29/2022] Open
Abstract
Human norovirus (HuNoV) is the leading cause of epidemic acute gastroenteritis worldwide. Type I interferons (IFN)-α/β are highly potent cytokines that are initially identified for their essential roles in antiviral defense. It was reported that HuNoV infection did not induce IFN-β expression but was controlled in the presence of IFN-β in human intestinal enteroids and a gnotobiotic pig model, suggesting that HuNoV has likely developed evasion countermeasures. In this study, we found that a cDNA clone of GII.4 HuNoV, the predominantly circulating genotype worldwide, inhibits the production of IFN-β and identified the viral NTPase as a key component responsible for such inhibition. HuNoV NTPase not only inhibits the activity of IFN-β promoter but also the mRNA and protein production of IFN-β. Additional studies indicate that NTPase inhibits the phosphorylation and nuclear translocation of interferon-regulatory factor-3 (IRF-3), leading to the suppression of IFN-β promoter activation. Mechanistically, NTPase interacts with IkB kinase ε (IKKε), an important factor for IRF-3 phosphorylation, and such interaction blocks the association of IKKε with unanchored K48-linked polyubiquitin chains, resulting in the inhibition of IKKε phosphorylation. Further studies demonstrated that the 1-179 aa domain of NTPase which interacts with IKKε is critical for the suppression of IFN-β production. Our findings highlight the role of HuNoV NTPase in the inhibition of IFN-β production, providing insights into a novel mechanism underlying how HuNoV evades the host innate immunity.
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Affiliation(s)
- Zifeng Zheng
- The Joint Laboratory of Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou, China.,The Joint Laboratory of Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Yuncheng Li
- State Key Laboratory of Virology, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Mudan Zhang
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yalan Liu
- State Key Laboratory of Virology, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Ming Fu
- The Joint Laboratory of Translational Precision Medicine, Guangzhou Women and Children's Medical Center, Guangzhou, China.,The Joint Laboratory of Translational Precision Medicine, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Sitang Gong
- Department of Gastroenterology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Qinxue Hu
- State Key Laboratory of Virology, Center for Biosafety Mega-Science, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.,Institute for Infection and Immunity, St George's, University of London, London, United Kingdom
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5
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Smertina E, Hall RN, Urakova N, Strive T, Frese M. Calicivirus Non-structural Proteins: Potential Functions in Replication and Host Cell Manipulation. Front Microbiol 2021; 12:712710. [PMID: 34335548 PMCID: PMC8318036 DOI: 10.3389/fmicb.2021.712710] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/21/2021] [Indexed: 01/15/2023] Open
Abstract
The Caliciviridae are a family of viruses with a single-stranded, non-segmented RNA genome of positive polarity. The ongoing discovery of caliciviruses has increased the number of genera in this family to 11 (Norovirus, Nebovirus, Sapovirus, Lagovirus, Vesivirus, Nacovirus, Bavovirus, Recovirus, Salovirus, Minovirus, and Valovirus). Caliciviruses infect a wide range of hosts that include fishes, amphibians, reptiles, birds, and marine and land mammals. All caliciviruses have a genome that encodes a major and a minor capsid protein, a genome-linked viral protein, and several non-structural proteins. Of these non-structural proteins, only the helicase, protease, and RNA-dependent RNA polymerase share clear sequence and structural similarities with proteins from other virus families. In addition, all caliciviruses express two or three non-structural proteins for which functions have not been clearly defined. The sequence diversity of these non-structural proteins and a multitude of processing strategies suggest that at least some have evolved independently, possibly to counteract innate and adaptive immune responses in a host-specific manner. Studying these proteins is often difficult as many caliciviruses cannot be grown in cell culture. Nevertheless, the study of recombinant proteins has revealed many of their properties, such as intracellular localization, capacity to oligomerize, and ability to interact with viral and/or cellular proteins; the release of non-structural proteins from transfected cells has also been investigated. Here, we will summarize these findings and discuss recent in silico studies that identified previously overlooked putative functional domains and structural features, including transmembrane domains that suggest the presence of viroporins.
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Affiliation(s)
- Elena Smertina
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Robyn N. Hall
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Nadya Urakova
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Michael Frese
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
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6
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In vitro translation of virally-encoded replication polyproteins to recapitulate polyprotein maturation processes. Protein Expr Purif 2020; 175:105694. [PMID: 32681958 DOI: 10.1016/j.pep.2020.105694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 11/21/2022]
Abstract
Single-stranded, positive-sense RNA viruses encode essential replication polyproteins which are composed of several domains. They are usually subjected to finely regulated proteolytic maturation processes to generate cleavage intermediates and end-products. Both polyproteins and maturation products play multiple key roles that ultimately allow synthesis of viral genome progeny. Despite the importance of these proteins in the course of viral replication, their structural properties, including the conformational changes regulating their numerous functions, are poorly described at the structural level. This lack of information is mainly due to the extreme difficulty to express large, membrane-bound, multi-domain proteins with criteria suitable for structural biology methods. To tackle this challenge, we have used a wheat-germ cell-free expression system. We firstly establish that this approach allows to synthesize viral polyproteins encoded by two unrelated positive-sense RNA viruses, a human norovirus and a plant tymovirus. Then, we demonstrate that these polyproteins are fully functional and are spontaneously auto-cleaved by their active protease domain, giving rise to natural maturation products. Moreover, we show that introduction of point mutations in polyproteins allows to inhibit the proteolytic maturation process of each virus. This allowed us to express and partially purify the uncleaved full-length norovirus polyprotein and the tymoviral RNA-dependent RNA polymerase. Thus, this study provides a powerful tool to obtain soluble viral polyproteins and their maturation products in order to conduct challenging structural biology projects and therefore solve unanswered questions.
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7
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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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8
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Ozaki K, Matsushima Y, Nagasawa K, Aso J, Saraya T, Yoshihara K, Murakami K, Motoya T, Ryo A, Kuroda M, Katayama K, Kimura H. Molecular Evolution of the Protease Region in Norovirus Genogroup II. Front Microbiol 2020; 10:2991. [PMID: 31993031 PMCID: PMC6971112 DOI: 10.3389/fmicb.2019.02991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 12/10/2019] [Indexed: 11/13/2022] Open
Abstract
Noroviruses are a major cause of viral epidemic gastroenteritis in humans worldwide. The protease (Pro) encoded in open reading frame 1 (ORF1) is an essential enzyme for proteolysis of the viral polyprotein. Although there are some reports regarding the evolutionary analysis of norovirus GII-encoding genes, there are few reports focused on the Pro region. We analyzed the molecular evolution of the Pro region of norovirus GII using bioinformatics approaches. A time-scaled phylogenetic tree of the Pro region constructed using a Bayesian Markov chain Monte Carlo method indicated that the common ancestor of GII diverged from GIV around 1680 CE [95% highest posterior density (HPD), 1607-1749]. The GII Pro region emerged around 1752 CE (95%HPD, 1707-1794), forming three further lineages. The evolutionary rate of GII Pro region was estimated at more than 10-3 substitutions/site/year. The distribution of the phylogenetic distances of each genotype differed, and showed genetic diversity. Mapping of the negative selection and substitution sites of the Pro structure showed that the substitution sites in the Pro protein were mostly produced under neutral selection in positions structurally adjacent to the active sites for proteolysis, whereas negative selection was observed in residues distant from the active sites. The phylodynamics of GII.P4, GII.P7, GII.P16, GII.P21, and GII.P31 indicated that their effective population sizes increased during the period from 2005 to 2016 and the increase in population size was almost consistent with the collection year of these genotypes. These results suggest that the Pro region of the norovirus GII evolved rapidly, but under no positive selection, with a high genetic divergence, similar to that of the RNA-dependent RNA polymerase (RdRp) region and the VP1 region of noroviruses.
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Affiliation(s)
- Keita Ozaki
- Graduate School of Health Sciences, Gunma Paz University, Takasaki, Japan
- Niitaka Co., Ltd., Osaka, Japan
| | - Yuki Matsushima
- Division of Virology, Kawasaki City Institute for Public Health, Kawasaki, Japan
| | | | - Jumpei Aso
- Department of Respiratory Medicine, Kyorin University School of Medicine, Mitaka, Japan
| | - Takeshi Saraya
- Department of Respiratory Medicine, Kyorin University School of Medicine, Mitaka, Japan
| | - Keisuke Yoshihara
- Department of Pediatric Infectious Diseases, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan
| | - Koichi Murakami
- Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Musashimurayama, Japan
| | - Takumi Motoya
- Ibaraki Prefectural Institute of Public Health, Mito, Japan
| | - Akihide Ryo
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama, Japan
| | - Makoto Kuroda
- Pathogen Genomics Center, National Institute of Infectious Diseases, Shinjuku, Japan
| | - Kazuhiko Katayama
- Laboratory of Viral Infection I, Graduate School of Infection Control Sciences, Kitasato Institute for Life Sciences, Kitasato University, Minato, Japan
| | - Hirokazu Kimura
- Graduate School of Health Sciences, Gunma Paz University, Takasaki, Japan
- Department of Microbiology, Yokohama City University School of Medicine, Yokohama, Japan
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9
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Katayama K. [Review Norovirus]. Uirusu 2020; 70:117-128. [PMID: 34544926 DOI: 10.2222/jsv.70.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Noroviruses commonly cause infectious gastroenteritis and massive food poisoning. There is an urgent need to elucidate the infection mechanism of noroviruses and to develop vaccines and therapeutic drugs. In addition to human disease, noroviruses have been implicated in animal disease. Noroviruses that cause murine diseases can be propagated in strained cultured cells, and for many years, murine norovirus has been used as a model for human noroviruses that could not be propagated in cultured cells. That model and advances in technology have been instrumental in basic studies of noroviruses. From structural biology, noroviruses undergo dynamic shape changes to improve their infectivity when they infect cells. New culture techniques have made human intestinal organoids available for studying the mechanisms of pathogenic expression of human noroviruses in the intestinal tract, mechanisms of infection growth, and the search for receptor molecules. Vaccines and antivirals using human intestinal organoids are under active development, and some are already in clinical trials. In this paper, I review the latest research results, vaccine development, and other advances from the history of norovirus discovery.
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Affiliation(s)
- Kazuhiko Katayama
- Laboratory of Viral Infection I, Department of Infection Control and Immunology, Ōmura Satoshi Memorial Institute & Graduate School of Infection Control Sciences, Kitasato University
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10
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Robinson BA, Van Winkle JA, McCune BT, Peters AM, Nice TJ. Caspase-mediated cleavage of murine norovirus NS1/2 potentiates apoptosis and is required for persistent infection of intestinal epithelial cells. PLoS Pathog 2019; 15:e1007940. [PMID: 31329638 PMCID: PMC6675124 DOI: 10.1371/journal.ppat.1007940] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/01/2019] [Accepted: 06/24/2019] [Indexed: 12/05/2022] Open
Abstract
Human norovirus (HNoV) is the leading cause of acute gastroenteritis and is spread by fecal shedding that can often persist for weeks to months after the resolution of symptoms. Elimination of persistent viral reservoirs has the potential to prevent outbreaks. Similar to HNoV, murine norovirus (MNV) is spread by persistent shedding in the feces and provides a tractable model to study molecular mechanisms of enteric persistence. Previous studies have identified non-structural protein 1 (NS1) from the persistent MNV strain CR6 as critical for persistent infection in intestinal epithelial cells (IECs), but its mechanism of action remains unclear. We now find that the function of CR6 NS1 is regulated by apoptotic caspase cleavage. Following induction of apoptosis in infected cells, caspases cleave the precursor NS1/2 protein, and this cleavage is prevented by mutation of caspase target motifs. These mutations profoundly compromise CR6 infection of IECs and persistence in the intestine. Conversely, NS1/2 cleavage is not strictly required for acute replication in extra-intestinal tissues or in cultured myeloid cells, suggesting an IEC-centric role. Intriguingly, we find that caspase cleavage of CR6 NS1/2 reciprocally promotes caspase activity, potentiates cell death, and amplifies spread among cultured IEC monolayers. Together, these data indicate that the function of CR6 NS1 is regulated by apoptotic caspases, and suggest that apoptotic cell death enables epithelial spread and persistent shedding. Human Norovirus infection is highly contagious and the most common cause of acute gastroenteritis. Norovirus can be persistently shed after resolution of symptoms, perpetuating or initiating new outbreaks. Murine norovirus (MNV) is also persistently shed, enabling study of host and viral determinants of norovirus pathogenesis. We previously identified a critical role for MNV non-structural protein 1 (NS1), in persistence. Herein we find that regulation of NS1 by host apoptotic caspases is required for infection of intestinal epithelial cells, but not for extra-intestinal spread. Additionally, we demonstrate that NS1 reciprocally promotes cell death and spread among epithelial cells. These data identify regulation of NS1 by host proteases and suggest that apoptotic death is a determinant of epithelial spread and persistence.
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Affiliation(s)
- Bridget A. Robinson
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Jacob A. Van Winkle
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Broc T. McCune
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - A. Mack Peters
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Timothy J. Nice
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, Oregon, United States of America
- * E-mail:
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11
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Kuiper BD, Muzzarelli KM, Keusch BJ, Holcomb J, Amblard F, Liu P, Zhou S, Kovari IA, Yang Z, Schinazi RF, Kovari LC. Expression, Purification and Characterization of a GII.4 Norovirus Protease from Minerva Virus. Infect Disord Drug Targets 2019; 18:224-232. [PMID: 29779487 DOI: 10.2174/1871526518666180521091158] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 04/30/2018] [Accepted: 05/15/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Noroviruses are the leading cause of acute gastroenteritis worldwide. Norovirus proteases, which are responsible for cleavage of the viral polyprotein, have become an attractive drug target to treat norovirus infections. Genogroup II (GII) noroviruses are responsible for a majority of outbreaks; however, limited data exists regarding GII norovirus proteases. METHODS We report here successful expression, purification, characterization, and inhibition of the Minerva virus protease (MVpro), a genogroup II genotype 4 (GII.4) norovirus protease. We observed MVpro as both a monomer and dimer in solution through sizeexclusion chromatography. In addition, MVpro cleaves the synthetic substrate mimicking the MVpro NS2/NS3 cleavage site more efficiently than other norovirus proteases such as the Norwalk virus protease (GI.1) and the MD145 protease (GII.4). RESULTS AND CONCLUSION Compound A, a potent inhibitor of MVpro, is a good starting point for the design of inhibitors to target GII.4 noroviruses. Furthermore, the results presented here will allow for future characterization of MVpro inhibitors as they are synthesized.
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Affiliation(s)
- Benjamin D Kuiper
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Kendall M Muzzarelli
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Bradley J Keusch
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Joshua Holcomb
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Franck Amblard
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Peng Liu
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Shaoman Zhou
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Iulia A Kovari
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Zhe Yang
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
| | - Raymond F Schinazi
- Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Ladislau C Kovari
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, MI 48201, United States
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12
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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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13
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Doerflinger SY, Cortese M, Romero-Brey I, Menne Z, Tubiana T, Schenk C, White PA, Bartenschlager R, Bressanelli S, Hansman GS, Lohmann V. Membrane alterations induced by nonstructural proteins of human norovirus. PLoS Pathog 2017; 13:e1006705. [PMID: 29077760 PMCID: PMC5678787 DOI: 10.1371/journal.ppat.1006705] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 11/08/2017] [Accepted: 10/20/2017] [Indexed: 01/09/2023] Open
Abstract
Human noroviruses (huNoV) are the most frequent cause of non-bacterial acute gastroenteritis worldwide, particularly genogroup II genotype 4 (GII.4) variants. The viral nonstructural (NS) proteins encoded by the ORF1 polyprotein induce vesical clusters harboring the viral replication sites. Little is known so far about the ultrastructure of these replication organelles or the contribution of individual NS proteins to their biogenesis. We compared the ultrastructural changes induced by expression of norovirus ORF1 polyproteins with those induced upon infection with murine norovirus (MNV). Characteristic membrane alterations induced by ORF1 expression resembled those found in MNV infected cells, consisting of vesicle accumulations likely built from the endoplasmic reticulum (ER) which included single membrane vesicles (SMVs), double membrane vesicles (DMVs) and multi membrane vesicles (MMVs). In-depth analysis using electron tomography suggested that MMVs originate through the enwrapping of SMVs with tubular structures similar to mechanisms reported for picornaviruses. Expression of GII.4 NS1-2, NS3 and NS4 fused to GFP revealed distinct membrane alterations when analyzed by correlative light and electron microscopy. Expression of NS1-2 induced proliferation of smooth ER membranes forming long tubular structures that were affected by mutations in the active center of the putative NS1-2 hydrolase domain. NS3 was associated with ER membranes around lipid droplets (LDs) and induced the formation of convoluted membranes, which were even more pronounced in case of NS4. Interestingly, NS4 was the only GII.4 protein capable of inducing SMV and DMV formation when expressed individually. Our work provides the first ultrastructural analysis of norovirus GII.4 induced vesicle clusters and suggests that their morphology and biogenesis is most similar to picornaviruses. We further identified NS4 as a key factor in the formation of membrane alterations of huNoV and provide models of the putative membrane topologies of NS1-2, NS3 and NS4 to guide future studies. Positive-strand RNA viruses induce membrane alterations harboring the viral replication complexes. In the case of human noroviruses (huNoV), the major cause of acute viral gastroenteritis, these are induced by the ORF1 polyprotein, which is post-translationally processed into the functional nonstructural (NS) proteins. Partly due to the lack of efficient cell culture models, little is known so far about membrane alterations induced by huNoV belonging to the most clinically relevant genogroup II, genotype 4 (GII.4), nor about the function of individual NS proteins in their formation. We therefore expressed ORF1 proteins of GII.4 and individual NS proteins in cells to study their contribution to viral replication complex formation. Expression of ORF1 proteins of GII.4 induced vesicular membrane alterations comparable to those found in infected cells and similar to picornaviruses and hepatitis C virus (HCV). GII.4 NS1-2, NS3 and NS4 are contributing to viral membrane alterations. Our work provides new insights into their function in huNoV induced replication complex formation while identifying NS4 as the most important single determinant. This knowledge might provide novel attractive targets for future therapies inhibiting the formation of the membranous viral replication complex, as exemplified by the efficacy of HCV NS5A inhibitors.
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Affiliation(s)
- Sylvie Y. Doerflinger
- Department of Infectious Diseases, Virology, Heidelberg University, Heidelberg, Germany
- Schaller Research Group at the University of Heidelberg and the DKFZ, Heidelberg, Germany
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Mirko Cortese
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Inés Romero-Brey
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Zach Menne
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Thibault Tubiana
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris Sud, Université Paris-Saclay, Gif sur Yvette cedex, France
| | - Christian Schenk
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Peter A. White
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, Australia
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
- German Center for Infection Research (DZIF), Heidelberg University, Heidelberg, Germany
| | - Stéphane Bressanelli
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris Sud, Université Paris-Saclay, Gif sur Yvette cedex, France
| | - Grant S. Hansman
- Department of Infectious Diseases, Virology, Heidelberg University, Heidelberg, Germany
- Schaller Research Group at the University of Heidelberg and the DKFZ, Heidelberg, Germany
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
- * E-mail:
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14
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Supadej K, Khamrin P, Kumthip K, Kochjan P, Yodmeeklin A, Ushijima H, Maneekarn N. Wide variety of recombinant strains of norovirus GII in pediatric patients hospitalized with acute gastroenteritis in Thailand during 2005 to 2015. INFECTION GENETICS AND EVOLUTION 2017; 52:44-51. [PMID: 28461205 DOI: 10.1016/j.meegid.2017.04.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 04/12/2017] [Accepted: 04/27/2017] [Indexed: 02/06/2023]
Abstract
Norovirus (NoV) has been reported as being a common cause of acute gastroenteritis both in children and adults worldwide. Of the many variants, NoV GII.4 is the most predominant genotype. One of the mechanisms that drives the evolution and emergence of new variants of NoV is homologous recombination. This study describes the genetic recombination involved in cases of NoV GII detected in pediatric patients with acute gastroenteritis in Chiang Mai, Thailand during 2005 to 2015. From a total of 1938 stool samples, 3 (0.15%) were positive for NoV GI and 298 (15.38%) were identified as NoV GII. The genotypes detected in this study were GI.6, GI.14, GII.1, GII.2, GII.3, GII.4, GII.6, GII.7, GII.12, GII.13, GII.14, GII.15, GII.16, GII.17, GII.20, and GII.21. The NoV recombinant strains were verified by analysis of the partial sequence of ORF1 (RdRp)/ORF2 (capsid) junction. Phylogenetic analyses of partial ORF1 and ORF2 regions resulted in the identification of 21 (6.98%) NoV recombinant strains. Among these, 9 recombination patterns were detected in this study; GII.Pe/GII.4, GII.Pg/GII.1, GII.Pg/GII.12, GII.P7/GII.6, GII.P7/GII.14, GII.P12/GII.4, GII.P16/GII.2, GII.P16/GII.13, and GII.P21/GII.3. The findings demonstrated the wide variety of recombinant strains of NoV GII strains detected in pediatric patients admitted to the hospitals with acute gastroenteritis in Chiang Mai, Thailand during the past decade.
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Affiliation(s)
- Kanittapon Supadej
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pattara Khamrin
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
| | - Kattareeya Kumthip
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Pakawat Kochjan
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Arpaporn Yodmeeklin
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Hiroshi Ushijima
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan; Department of Developmental Medical Sciences, School of International Health, Graduate School of Medicine, The University of Tokyo, Japan
| | - Niwat Maneekarn
- Department of Microbiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
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15
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16
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Moore MD, Goulter RM, Jaykus LA. Human norovirus as a foodborne pathogen: challenges and developments. Annu Rev Food Sci Technol 2015; 6:411-33. [PMID: 25884284 DOI: 10.1146/annurev-food-022814-015643] [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] [Indexed: 11/09/2022]
Abstract
Human noroviruses (NoVs) are the leading cause of foodborne illness in the United States, and they exact a considerable human and economic burden worldwide. In fact, the many challenging aspects of human NoV have caused some to call it the nearly perfect foodborne pathogen. In this review, a brief overview of NoVs and their genetic structure is provided. Additionally, the challenges and recent developments related to human NoVs regarding viral evolution, transmission, epidemiology, outbreak identification, cultivation, animal and human models, and detection are presented.
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Affiliation(s)
- Matthew D Moore
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina 27695;
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17
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Miles LA, Brennen WN, Rudin CM, Poirier JT. Seneca Valley Virus 3Cpro Substrate Optimization Yields Efficient Substrates for Use in Peptide-Prodrug Therapy. PLoS One 2015; 10:e0129103. [PMID: 26069962 PMCID: PMC4466507 DOI: 10.1371/journal.pone.0129103] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/04/2015] [Indexed: 01/13/2023] Open
Abstract
The oncolytic picornavirus Seneca Valley Virus (SVV-001) demonstrates anti-tumor activity in models of small cell lung cancer (SCLC), but may ultimately need to be combined with cytotoxic therapies to improve responses observed in patients. Combining SVV-001 virotherapy with a peptide prodrug activated by the viral protease 3Cpro is a novel strategy that may increase the therapeutic potential of SVV-001. Using recombinant SVV-001 3Cpro, we measured cleavage kinetics of predicted SVV-001 3Cpro substrates. An efficient substrate, L/VP4 (kcat/KM = 1932 ± 183 M(-1)s(-1)), was further optimized by a P2' N→P substitution yielding L/VP4.1 (kcat/KM = 17446 ± 2203 M(-1)s(-1)). We also determined essential substrate amino acids by sequential N-terminal deletion and substitution of amino acids found in other picornavirus genera. A peptide corresponding to the L/VP4.1 substrate was selectively cleaved by SVV-001 3Cpro in vitro and was stable in human plasma. These data define an optimized peptide substrate for SVV-001 3Cpro, with direct implications for anti-cancer therapeutic development.
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Affiliation(s)
- Linde A. Miles
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - W. Nathaniel Brennen
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Charles M. Rudin
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, United States of America
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - John T. Poirier
- Department of Oncology, Johns Hopkins University, Baltimore, Maryland, United States of America
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18
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Fernandes H, Leen EN, Cromwell H, Pfeil MP, Curry S. Structure determination of Murine Norovirus NS6 proteases with C-terminal extensions designed to probe protease-substrate interactions. PeerJ 2015; 3:e798. [PMID: 25755927 PMCID: PMC4349150 DOI: 10.7717/peerj.798] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/05/2015] [Indexed: 01/20/2023] Open
Abstract
Noroviruses are positive-sense single-stranded RNA viruses. They encode an NS6 protease that cleaves a viral polyprotein at specific sites to produce mature viral proteins. In an earlier study we obtained crystals of murine norovirus (MNV) NS6 protease in which crystal contacts were mediated by specific insertion of the C-terminus of one protein (which contains residues P5-P1 of the NS6-7 cleavage junction) into the peptide binding site of an adjacent molecule, forming an adventitious protease-product complex. We sought to reproduce this crystal form to investigate protease–substrate complexes by extending the C-terminus of NS6 construct to include residues on the C-terminal (P′) side of the cleavage junction. We report the crystallization and crystal structure determination of inactive mutants of murine norovirus NS6 protease with C-terminal extensions of one, two and four residues from the N-terminus of the adjacent NS7 protein (NS6 1′, NS6 2′, NS6 4′). We also determined the structure of a chimeric extended NS6 protease in which the P4-P4′ sequence of the NS6-7 cleavage site was replaced with the corresponding sequence from the NS2-3 cleavage junction (NS6 4′ 2|3).The constructs NS6 1′ and NS6 2′ yielded crystals that diffracted anisotropically. We found that, although the uncorrected data could be phased by molecular replacement, refinement of the structures stalled unless the data were ellipsoidally truncated and corrected with anisotropic B-factors. These corrections significantly improved phasing by molecular replacement and subsequent refinement.The refined structures of all four extended NS6 proteases are very similar in structure to the mature MNV NS6—and in one case reveal additional details of a surface loop. Although the packing arrangement observed showed some similarities to those observed in the adventitious protease-product crystals reported previously, in no case were specific protease–substrate interactions observed.
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Affiliation(s)
| | - Eoin N Leen
- Department of Life Sciences, Imperial College London , UK
| | | | | | - Stephen Curry
- Department of Life Sciences, Imperial College London , UK
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19
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Herod M, Prince C, Skilton R, Ward V, Cooper J, Clarke I. Structure-based design and functional studies of novel noroviral 3C protease chimaeras offer insights into substrate specificity. Biochem J 2014; 464:461-72. [PMID: 25275273 PMCID: PMC4613530 DOI: 10.1042/bj20140959] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/26/2014] [Accepted: 10/02/2014] [Indexed: 01/30/2023]
Abstract
The norovirus NS6 protease is a key target for anti-viral drug development. Noroviruses encode a 2200 amino acid polyprotein which is cleaved by this critical protease at five defined boundary substrates into six mature non-structural (NS) proteins. Studies of the human norovirus (HNV) NS6 protease, in the context of a full ORF1 polyprotein, have been severely hampered because HNVs are not culturable. Thus, investigations into the HNV NS6 protease have been largely restricted to in vitro assays using Escherichia coli-expressed, purified enzyme. The NS6 protease is formed of two distinct domains joined by a linking loop. Structural data suggest that domain 2 of the protease possesses substantial substrate binding pockets which form the bulk of the interactions with the NS boundaries and largely dictate boundary specificity and cleavage. We have constructed chimaeric murine norovirus (MNV) genomes carrying individual domains from the HNV protease and demonstrated by cell transfection that chimaeric HNV proteases have functional activity in the context of the full-length ORF1 polyprotein. Although domain 2 primarily confers boundary specificity, our data suggest that an inter-domain interaction exists within HNV NS6 protease which influences cleavage of specific substrates. The present study also shows that chimaeric MNVs provide improved models for studying HNV protein function in the context of a full ORF1 polyprotein.
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Affiliation(s)
- Morgan R. Herod
- Molecular Microbiology Group, University of Southampton, Southampton SO16 6YD, U.K
| | - Cynthia A. Prince
- Molecular Microbiology Group, University of Southampton, Southampton SO16 6YD, U.K
| | - Rachel J. Skilton
- Molecular Microbiology Group, University of Southampton, Southampton SO16 6YD, U.K
| | - Vernon K. Ward
- Otago School of Medical Sciences, Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Jonathan B. Cooper
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, U.K
| | - Ian N. Clarke
- Molecular Microbiology Group, University of Southampton, Southampton SO16 6YD, U.K
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20
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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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21
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May J, Viswanathan P, Ng KKS, Medvedev A, Korba B. The p4-p2' amino acids surrounding human norovirus polyprotein cleavage sites define the core sequence regulating self-processing order. J Virol 2014; 88:10738-47. [PMID: 24991013 PMCID: PMC4178882 DOI: 10.1128/jvi.01357-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 06/30/2014] [Indexed: 01/16/2023] Open
Abstract
UNLABELLED Noroviruses (NoV) are members of the family Caliciviridae. The human NoV open reading frame 1 (ORF1) encodes a 200-kDa polyprotein which is cleaved by the viral 20-kDa 3C-like protease (Pro, NS6) into 6 nonstructural proteins that are necessary for viral replication. The NoV ORF1 polyprotein is processed in a specific order, with "early" sites (NS1/2-3 and NS3-4) being cleaved rapidly and three "late" sites (NS4-5, NS5-6, and NS6-7) processed subsequently and less efficiently. Previously, we demonstrated that the NoV polyprotein processing order is directly correlated with the efficiency of the enzyme, which is regulated by the primary amino acid sequences surrounding ORF1 cleavage sites. Using fluorescence resonance energy transfer (FRET) peptides representing the NS2-3 and NS6-7 ORF1 cleavage sites, we now demonstrate that the amino acids spanning positions P4 to P2' (P4-P2') surrounding each site comprise the core sequence controlling NoV protease enzyme efficiency. Furthermore, the NoV polyprotein self-processing order can be altered by interchanging this core sequence between NS2-3 and any of the three late sites in in vitro transcription-translation assays. We also demonstrate that the nature of the side chain at the P3 position for the NS1/2-3 (Nterm/NTPase) site confers significant influence on enzyme catalysis (kcat and kcat/Km), a feature overlooked in previous structural studies. Molecular modeling provides possible explanations for the P3 interactions with NoV protease. IMPORTANCE Noroviruses (NoV) are the prevailing cause of nonbacterial acute gastroenteritis worldwide and pose a significant financial burden on health care systems. Proteolytic processing of the viral nonstructural polyprotein is required for norovirus replication. Previously, the core sequence of amino acids surrounding the scissile bonds responsible for governing the relative processing order had not been determined. Using both FRET-based peptides and full-length NoV polyprotein, we have successfully demonstrated that the core sequences spanning positions P4-P2' surrounding the NS2-3, NS4-5, NS5-6, and NS6-7 cleavage sites contain all of the structural information necessary to control processing order. We also provide insight into a previously overlooked role for the NS2-3 P3 residue in enzyme efficiency. This article builds upon our previous studies on NoV protease enzymatic activities and polyprotein processing order. Our work provides significant additional insight into understanding viral polyprotein processing and has important implications for improving the design of inhibitors targeting the NoV protease.
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Affiliation(s)
- Jared May
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
| | - Prasanth Viswanathan
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
| | - Kenneth K-S Ng
- Department of Biological Sciences and Alberta Glycomics Centre, University of Calgary, Calgary, Alberta, Canada
| | - Alexei Medvedev
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
| | - Brent Korba
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
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Development of a Gaussia luciferase-based human norovirus protease reporter system: cell type-specific profile of Norwalk virus protease precursors and evaluation of inhibitors. J Virol 2014; 88:10312-26. [PMID: 25008934 DOI: 10.1128/jvi.01111-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
UNLABELLED Norwalk virus (NV) is the prototype strain of human noroviruses (HuNoVs), a group of positive-strand RNA viruses in the Caliciviridae family and the leading cause of epidemic gastroenteritis worldwide. Investigation of HuNoV replication and development of antiviral therapeutics in cell culture remain challenging tasks. Here, we present NoroGLuc, a HuNoV protease reporter system based on a fusion of NV p41 protein with a naturally secreted Gaussia luciferase (GLuc), linked by the p41/p22 cleavage site for NV protease (Pro). trans cleavage of NoroGLuc by NV Pro or Pro precursors results in release and secretion of an active GLuc. Using this system, we observed a cell type-specific activity profile of NV Pro and Pro precursors, suggesting that the activity of NV Pro is modulated by other viral proteins in the precursor forms and strongly influenced by cellular factors. NoroGLuc was also cleaved by Pro and Pro precursors generated from replication of NV stool RNA in transfected cells, resulting in a measurable increase of secreted GLuc. Truncation analysis revealed that the N-terminal membrane association domain of NV p41 is critical for NoroGLuc activity. Although designed for NV, a genogroup GI.1 norovirus, NoroGLuc also efficiently detects Pro activities from GII.3 and GII.4 noroviruses. At noncytotoxic concentrations, protease inhibitors ZnCl2 and Nα-p-tosyl-l-lysine chloromethyl ketone (TLCK) exhibited dose-dependent inhibitory effects on a GII.4 Pro by NoroGLuc assay. These results establish NoroGLuc as a pan-genogroup HuNoV protease reporter system that can be used for the study of HuNoV proteases and precursors, monitoring of viral RNA replication, and evaluation of antiviral agents. IMPORTANCE Human noroviruses are the leading cause of epidemic gastroenteritis worldwide. Currently, there are no vaccines or antiviral drugs available to counter these highly contagious viruses. These viruses are currently noncultivatable in cell culture. Here, we report the development of a novel cell-based reporter system called NoroGLuc that can be used for studying norovirus replication and also for screening/evaluation of antiviral agents. This system is based on the fusion between viral protein p41 and a naturally secreted Gaussia luciferase (GLuc) with a cleavage site that can be recognized by the viral protease. Cleavage of this fusion protein by the viral protease results in the release and secretion of an active GLuc. Using NoroGLuc, we demonstrated a cell type-specific activity profile of the viral protease and its precursors and dose-dependent inhibitory effects of two protease inhibitors. This novel reporter system should be useful in probing norovirus replication and evaluating antiviral agents.
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23
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PPNDS inhibits murine Norovirus RNA-dependent RNA-polymerase mimicking two RNA stacking bases. FEBS Lett 2014; 588:1720-5. [DOI: 10.1016/j.febslet.2014.03.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 02/27/2014] [Accepted: 03/10/2014] [Indexed: 11/23/2022]
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Herod MR, Salim O, Skilton RJ, Prince CA, Ward VK, Lambden PR, Clarke IN. Expression of the murine norovirus (MNV) ORF1 polyprotein is sufficient to induce apoptosis in a virus-free cell model. PLoS One 2014; 9:e90679. [PMID: 24599381 PMCID: PMC3944349 DOI: 10.1371/journal.pone.0090679] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 02/04/2014] [Indexed: 12/13/2022] Open
Abstract
Investigations into human norovirus infection, replication and pathogenesis, as well as the development of potential antiviral agents, have been restricted by the lack of a cell culture system for human norovirus. To date, the optimal cell culture surrogate virus model for studying human norovirus biology is the murine norovirus (MNV). In this report we generate a tetracycline-regulated, inducible eukaryotic cell system expressing the entire MNV ORF1 polyprotein. Once induced, the MNV ORF1 polyprotein was faithfully processed to the six mature non-structural proteins that predominately located to a discrete perinuclear region, as has been observed in active MNV infection. Furthermore, we found that expression of the ORF1 polyprotein alone was sufficient to induce apoptosis, characterised by caspase-9 activation and survivin down-regulation. This cell line provides a valuable new tool for studying MNV ORF1 non-structural protein function, screening for potential antiviral agents and acts as a proof-of-principle for such systems to be developed for human noroviruses.
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Affiliation(s)
- Morgan R. Herod
- Molecular Microbiology Group, University of Southampton, Southampton, United Kingdom
| | - Omar Salim
- Molecular Microbiology Group, University of Southampton, Southampton, United Kingdom
| | - Rachel J. Skilton
- Molecular Microbiology Group, University of Southampton, Southampton, United Kingdom
| | - Cynthia A. Prince
- Molecular Microbiology Group, University of Southampton, Southampton, United Kingdom
| | - Vernon K. Ward
- Otago School of Medical Sciences, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Paul R. Lambden
- Molecular Microbiology Group, University of Southampton, Southampton, United Kingdom
| | - Ian N. Clarke
- Molecular Microbiology Group, University of Southampton, Southampton, United Kingdom
- * E-mail:
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Myrmel M. Development of a strand specific SYBRGreen RT-PCR for a GIII.2 bovine norovirus. J Virol Methods 2013; 190:17-9. [PMID: 23538037 DOI: 10.1016/j.jviromet.2013.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 03/08/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022]
Abstract
A strand specific SYBRGreen RT-PCR was developed for a bovine norovirus (GIII.2). HEK293 cells were transfected with a plasmid containing the complete virus genome and copy DNA was produced with viral RNA strand-specific primers that introduced nucleotide changes. Amplicons from the negative and positive viral RNA strands, and from potential transcripts made by sequence independent transcription, were separated by melting curve analysis. The RT-PCR showed high strand specificity and could be a useful tool to study virus replication in replicon and reverse genetic systems and in screening for low levels of virus replication in norovirus permissive cell lines.
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Affiliation(s)
- Mette Myrmel
- Norwegian School of Veterinary Science, P.B. 8146 Dep., 0033 Oslo, Norway.
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Structures of the compact helical core domains of feline calicivirus and murine norovirus VPg proteins. J Virol 2013; 87:5318-30. [PMID: 23487472 PMCID: PMC3648151 DOI: 10.1128/jvi.03151-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We report the solution structures of the VPg proteins from feline calicivirus (FCV) and murine norovirus (MNV), which have been determined by nuclear magnetic resonance spectroscopy. In both cases, the core of the protein adopts a compact helical structure flanked by flexible N and C termini. Remarkably, while the core of FCV VPg contains a well-defined three-helix bundle, the MNV VPg core has just the first two of these secondary structure elements. In both cases, the VPg cores are stabilized by networks of hydrophobic and salt bridge interactions. The Tyr residue in VPg that is nucleotidylated by the viral NS7 polymerase (Y24 in FCV, Y26 in MNV) occurs in a conserved position within the first helix of the core. Intriguingly, given its structure, VPg would appear to be unable to bind to the viral polymerase so as to place this Tyr in the active site without a major conformation change to VPg or the polymerase. However, mutations that destabilized the VPg core either had no effect on or reduced both the ability of the protein to be nucleotidylated and virus infectivity and did not reveal a clear structure-activity relationship. The precise role of the calicivirus VPg core in virus replication remains to be determined, but knowledge of its structure will facilitate future investigations.
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Abstract
Norovirus (NoV) are the most common cause of acute gastroenteritidis in humans worldwide. They are transmitted through consumption of contaminated food, or mostly by direct person-to-person contact. However, susceptibility to NoV infection is variable. NoVs recognize carbohydrate ligand, including A, B, H and Lewis histoblood group antigen (HBGAs) for attachment to human epithelial cells. Synthesis of these HBGAs requires various glycosyltransferase encoded by the ABO, FUT2, FUT3 genes. The presence of distinct carbohydrates structures dependent upon the combined polymorphism at the FUT2, FUT3 and ABO loci influences susceptibility to NoV infection. NoV-glycan interactions studies show that different strains recognize specific HBGAs. Together with herd immunity, HBGAs play a major role in the epidemiology and evolution of NoVs.
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Affiliation(s)
- N Ruvoën
- Unité de maladies réglementées - zoonoses, Oniris - École nationale vétérinaire, agroalimentaire et de l'alimentation Nantes Atlantique, site de la Chantrerie, 44307 Nantes, France.
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28
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Structural basis of substrate specificity and protease inhibition in Norwalk virus. J Virol 2013; 87:4281-92. [PMID: 23365454 DOI: 10.1128/jvi.02869-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Norwalk virus (NV), the prototype human calicivirus, is the leading cause of nonbacterial acute gastroenteritis. The NV protease cleaves the polyprotein encoded by open reading frame 1 of the viral genome at five nonhomologous sites, releasing six nonstructural proteins that are essential for viral replication. The structural details of how NV protease recognizes multiple substrates are unclear. In our X-ray structure of an NV protease construct, we observed that the C-terminal tail, representing the native substrate positions P5 to P1, is inserted into the active site cleft of the neighboring protease molecule, providing atomic details of how NV protease recognizes a substrate. The crystallographic structure of NV protease with the C-terminal tail redesigned to mimic P4 to P1 of another substrate site provided further structural details on how the active site accommodates sequence variations in the substrates. Based on these structural analyses, substrate-based aldehyde inhibitors were synthesized and screened for inhibition potency. Crystallographic structures of the protease in complex with each of the three most potent inhibitors were determined. These structures showed concerted conformational changes in the S4 and S2 pockets of the protease to accommodate variations in the P4 and P2 residues of the substrate/inhibitor, which could be a mechanism for how the NV protease recognizes multiple sites in the polyprotein with differential affinities during virus replication. These structures further indicate that the mechanism of inhibition by these inhibitors involves covalent bond formation with the side chain of the conserved cysteine in the active site by nucleophilic addition, and such substrate-based aldehydes could be effective protease inhibitors.
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A single-amino-acid change in murine norovirus NS1/2 is sufficient for colonic tropism and persistence. J Virol 2012; 87:327-34. [PMID: 23077309 DOI: 10.1128/jvi.01864-12] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human norovirus (HuNoV) is the major cause of acute nonbacterial gastroenteritis worldwide but has no clear animal reservoir. HuNoV can persist after the resolution of symptoms, and this persistence may be essential for viral maintenance within the population. Many strains of the related murine norovirus (MNV) also persist, providing a tractable animal model for studying norovirus (NoV) persistence. We have used recombinant cDNA clones of representative persistent (CR6) and nonpersistent (CW3) strains to identify a domain within the nonstructural gene NS1/2 that is necessary and sufficient for persistence. Furthermore, we found that a single change of aspartic acid to glutamic acid in CW3 NS1/2 was sufficient for persistence. This same conservative change also caused increased growth of CW3 in the proximal colon, which we found to be a major tissue reservoir of MNV persistence, suggesting that NS1/2 determines viral tropism that is necessary for persistence. These findings represent the first identified function for NoV NS1/2 during infection and establish a novel model system for the study of enteric viral persistence.
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31
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Rocha-Pereira J, Jochmans D, Dallmeier K, Leyssen P, Cunha R, Costa I, Nascimento MSJ, Neyts J. Inhibition of norovirus replication by the nucleoside analogue 2'-C-methylcytidine. Biochem Biophys Res Commun 2012; 427:796-800. [PMID: 23063849 DOI: 10.1016/j.bbrc.2012.10.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2012] [Accepted: 10/01/2012] [Indexed: 12/22/2022]
Abstract
We here report on the activity of 2'-C-methylcytidine (2CMC) [a nucleoside polymerase inhibitor of the hepatitis C virus (HCV)] on the in vitro replication of (murine) norovirus (MNV). 2CMC inhibits (i) virus-induced CPE formation, (ii) viral RNA synthesis and (iii) infectious progeny formation with EC(50) values of ∼2μM. 2CMC acts at a time-point that coincides with the onset of viral RNA synthesis. Even following 30 passages of selective pressure no MNV-resistant virus was selected, which is in line with the high barrier to resistance of the nucleoside analogue for HCV. When combined with the broad-spectrum RNA virus inhibitor ribavirin, a marked antagonistic activity was observed indicating that these molecules should not be combined for the treatment of norovirus infections. Our results suggest that 2'-C-methyl nucleoside analogues should be further explored for the treatment and prophylaxis of norovirus infections.
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Affiliation(s)
- J Rocha-Pereira
- Laboratório de Microbiologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
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32
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cDNA cloning of Korean human norovirus and nucleotidylylation of VPg by norovirus RNA-dependent RNA polymerase. J Microbiol 2012; 50:625-30. [PMID: 22923111 DOI: 10.1007/s12275-012-2087-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 05/29/2012] [Indexed: 10/28/2022]
Abstract
Norovirus, a member of the Caliciviridae family, is a major causative agent of gastroenteritis worldwide. The cDNA of the entire genome of human norovirus (HuNV) was cloned using the RNA extracted from the stool sample of a Korean patient. The RNA genome consists of 7,559 nucleotides, carries 3 open reading frames (ORFs), 5 and 3 noncoding regions, and a poly(A) tail at the 3 end. Phylogenic analysis of the nucleotide sequence indicated that it belongs to GII.4, the most dominant genogroup. To analyze RNA synthesis and nucleotidylylation of VPg by RNA-dependent RNA polymerase (RdRp), recombinant RdRp and VPg were expressed in Escherichia coli as His-tagged forms. The HuNV RdRp exhibited template and divalent cation-dependent RNA synthesis in vitro. The HuNV RdRp nucleotidylylated HuNV VPg but not murine norovirus (MNV) VPg, whereas MNV RdRp nucleotidylylated both MNV and HuNV VPg more efficiently than HuNV RdRp.
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33
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Leen EN, Baeza G, Curry S. Structure of a murine norovirus NS6 protease-product complex revealed by adventitious crystallisation. PLoS One 2012; 7:e38723. [PMID: 22685603 PMCID: PMC3369882 DOI: 10.1371/journal.pone.0038723] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/14/2012] [Indexed: 01/19/2023] Open
Abstract
Murine noroviruses have emerged as a valuable tool for investigating the molecular basis of infection and pathogenesis of the closely related human noroviruses, which are the major cause of non-bacterial gastroenteritis. The replication of noroviruses relies on the proteolytic processing of a large polyprotein precursor into six non-structural proteins (NS1–2, NS3, NS4, NS5, NS6pro, NS7pol) by the virally-encoded NS6 protease. We report here the crystal structure of MNV NS6pro, which has been determined to a resolution of 1.6 Å. Adventitiously, the crystal contacts are mediated in part by the binding of the C-terminus of NS6pro within the peptide-binding cleft of a neighbouring molecule. This insertion occurs for both molecules in the asymmetric unit of the crystal in a manner that is consistent with physiologically-relevant binding, thereby providing two independent views of a protease-peptide complex. Since the NS6pro C-terminus is formed in vivo by NS6pro processing, these crystal contacts replicate the protease-product complex that is formed immediately following cleavage of the peptide bond at the NS6-NS7 junction. The observed mode of binding of the C-terminal product peptide yields new insights into the structural basis of NS6pro specificity.
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Affiliation(s)
- Eoin N. Leen
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Gabriela Baeza
- Department of Life Sciences, Imperial College, London, United Kingdom
| | - Stephen Curry
- Department of Life Sciences, Imperial College, London, United Kingdom
- * E-mail:
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34
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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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35
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Hussey RJ, Coates L, Gill RS, Erskine PT, Coker SF, Mitchell E, Cooper JB, Wood S, Broadbridge R, Clarke IN, Lambden PR, Shoolingin-Jordan PM. A structural study of norovirus 3C protease specificity: binding of a designed active site-directed peptide inhibitor. Biochemistry 2011; 50:240-9. [PMID: 21128685 PMCID: PMC3058531 DOI: 10.1021/bi1008497] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 11/25/2010] [Indexed: 11/29/2022]
Abstract
Noroviruses are the major cause of human epidemic nonbacterial gastroenteritis. Viral replication requires a 3C cysteine protease that cleaves a 200 kDa viral polyprotein into its constituent functional proteins. Here we describe the X-ray structure of the Southampton norovirus 3C protease (SV3CP) bound to an active site-directed peptide inhibitor (MAPI) which has been refined at 1.7 Å resolution. The inhibitor, acetyl-Glu-Phe-Gln-Leu-Gln-X, which is based on the most rapidly cleaved recognition sequence in the 200 kDa polyprotein substrate, reacts covalently through its propenyl ethyl ester group (X) with the active site nucleophile, Cys 139. The structure permits, for the first time, the identification of substrate recognition and binding groups in a noroviral 3C protease and thus provides important new information for the development of antiviral prophylactics.
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Affiliation(s)
- Robert J. Hussey
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, U.K
| | - Leighton Coates
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Raj S. Gill
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, U.K
| | - Peter T. Erskine
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, U.K
| | - Shu-Fen Coker
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, U.K
| | - Ed Mitchell
- European Synchrotron Radiation Facility, BP 220, F-38043, Grenoble Cedex 9, France
| | - Jonathan B. Cooper
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, U.K
| | - Steve Wood
- Laboratory for Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Division of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, U.K
| | - Robert Broadbridge
- Peptide Protein Research Ltd., Knowle Village Business Park, Wickham, Hants PO17 5DY, U.K
| | - Ian N. Clarke
- Molecular Microbiology Group, Division of Infection, Inflammation and Immunity, University Medical School, Southampton General Hospital, Southampton, SO16 6YD, U.K
| | - Paul R. Lambden
- Molecular Microbiology Group, Division of Infection, Inflammation and Immunity, University Medical School, Southampton General Hospital, Southampton, SO16 6YD, U.K
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Hillenbrand B, Günzel D, Richter JF, Höhne M, Schreier E, Schulzke JD, Mankertz J. Norovirus non-structural protein p20 leads to impaired restitution of epithelial defects by inhibition of actin cytoskeleton remodelling. Scand J Gastroenterol 2010; 45:1307-19. [PMID: 20695836 DOI: 10.3109/00365521.2010.483013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Norovirus is the most common cause of acute gastroenteritis in humans worldwide. Typical symptoms are vomiting, nausea and severe watery diarrhea. Because of the lack of cell lines susceptible to human norovirus infection, pathomechanisms and replication cycle are largely unknown. Here, we address the issue of how norovirus infection could lead to epithelial barrier dysfunction. MATERIAL AND METHODS Expression of the non-structural norovirus protein p20 in the epithelial cell line HT-29/B6 was activated through a tetracycline sensitive promoter. Tight junction proteins were studied by Western blot and confocal laser scanning microscopy. Apoptoses were detected in TUNEL stainings. Epithelial restitution was monitored by conductance scanning after induction of single cell lesions. RESULTS Changes in the expression or localization of the tight junction proteins occludin and/or claudin-1, -2,- 3, -4, -5, -7 and -8 could be ruled out to mediate epithelial barrier modulation. Cell motility was also unaltered by p20. Investigation of epithelial apoptosis revealed an accumulation of apoptic cells in epithelial monolayers after induction of p20 expression. In epithelial cell restitution assays, an arrest was identified in p20 expressing cells. Fluorescence microscopy revealed an inability for condensation and redistribution of cellular actin, which led to a reduced transepithelial electrical resistance. CONCLUSIONS Functional data for norovirus protein p20 suggest a role in modulation of the actin cytoskeleton leading to barrier dysfunction through impairment of restitution of epithelial defects.
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Affiliation(s)
- Bernd Hillenbrand
- Department of Gastroenterology, Infectious Diseases and Rheumatology, Charité Universitätsmedizin Berlin, Berlin, Germany
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37
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Hussey RJ, Coates L, Gill RS, Wright JN, Sarwar M, Coker S, Erskine PT, Cooper JB, Wood S, Clarke IN, Lambden PR, Broadbridge R, Shoolingin-Jordan PM. Crystallization and preliminary X-ray diffraction analysis of the protease from Southampton norovirus complexed with a Michael acceptor inhibitor. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1544-8. [PMID: 21045318 PMCID: PMC3001671 DOI: 10.1107/s1744309110039059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 09/29/2010] [Indexed: 11/10/2022]
Abstract
Noroviruses are the predominant cause of human epidemic nonbacterial gastroenteritis. Viral replication requires a cysteine protease that cleaves a 200 kDa viral polyprotein into its constituent functional parts. Here, the crystallization of the recombinant protease from the Southampton norovirus is described. Whilst the native crystals were found to diffract only to medium resolution (2.9 Å), cocrystals of an inhibitor complex diffracted X-rays to 1.7 Å resolution. The polypeptide inhibitor (Ac-EFQLQ-propenyl ethyl ester) possesses an amino-acid sequence designed to match the substrate specificity of the enzyme, but was synthesized with a reactive Michael acceptor group at the C-terminal end.
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Affiliation(s)
- R. J. Hussey
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, England
| | - L. Coates
- Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - R. S. Gill
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - J. N. Wright
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, England
| | - M. Sarwar
- School of Biological Sciences, University of Southampton, Southampton SO16 7PX, England
| | - S. Coker
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - P. T. Erskine
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - J. B. Cooper
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - S. Wood
- Laboratory of Protein Crystallography, Centre for Amyloidosis and Acute Phase Proteins, UCL Department of Medicine (Royal Free Campus), Rowland Hill Street, London NW3 2PF, England
| | - I. N. Clarke
- Molecular Microbiology Group, Division of Infection, Inflammation and Immunity, University Medical School, Southampton General Hospital, Southampton SO16 6YD, England
| | - P. R. Lambden
- Molecular Microbiology Group, Division of Infection, Inflammation and Immunity, University Medical School, Southampton General Hospital, Southampton SO16 6YD, England
| | - R. Broadbridge
- Peptide Protein Research Ltd, E2 Knowle Village Business Park, Wickham, Hants PO17 5DY, England
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Kim EJ, Cheon DS, Jeong HS, Park SH, Kim CK, Choi SS, Oh SA, Cho SJ, Han KY, Kim MY. Genetic diversity of norovirus in outbreaks of gastroenteritis in Seoul. Food Sci Biotechnol 2010. [DOI: 10.1007/s10068-010-0153-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Molecular epidemiology of norovirus infections in children and adults: sequence analysis of region C indicates genetic diversity of NVGII strains in Kolkata, India. Epidemiol Infect 2010; 139:910-8. [DOI: 10.1017/s0950268810001731] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SUMMARYFaecal specimens of diarrhoea cases (n=2495, collected between November 2007 and October 2009) from Infectious Diseases and Beliaghata General (ID&BG) Hospital, Kolkata, India, were screened by RT–PCR using specific primers targeting region C of the capsid gene of noroviruses (NoVs) to determine the seasonal distribution and clinical characteristics of NoVs associated with diarrhoea. NoV infection was detected in 78 cases, mostly in children aged <2 years. In 22/78 positive cases, the virus was detected as the sole agent; others were as mixed infections with other enteric pathogens. Sequencing of NVGII strains showed clustering with GII.4 NoVs followed by GII.13 and GII.6 NoVs. Clinical characteristics of the diarrhoeic children and adults in Kolkata indicated that NoV infections were detected throughout the year and were associated with a mild degree of dehydration.
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40
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Yun SI, Kim JK, Song BH, Jeong AY, Jee YM, Lee CH, Paik SY, Koo Y, Jeon I, Byun SJ, Lee YM. Complete genome sequence and phylogenetic analysis of a recombinant Korean norovirus, CBNU1, recovered from a 2006 outbreak. Virus Res 2010; 152:137-52. [PMID: 20599576 DOI: 10.1016/j.virusres.2010.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 06/17/2010] [Accepted: 06/18/2010] [Indexed: 11/19/2022]
Abstract
We have determined the complete nucleotide and deduced amino acid sequences of the RNA genome of CBNU1, a human norovirus (NoV) recovered from a 2006 outbreak in South Korea. The genome of 7547 nucleotides, excluding a 3'-poly(A) tail of 11-105 nucleotides, encodes three overlapping open reading frames (ORFs): ORF1 (nucleotides 5-5104), ORF2 (nucleotides 5085-6731), and ORF3 (nucleotides 6731-7495). In a comparison to 108 other currently available completely sequenced NoVs representing all five genogroups (GI-GV) except GIV, the CBNU1 strain was highly similar to GII.3 NoVs. Multiple sequence alignments of the completely sequenced NoV genomes revealed five hypervariable regions throughout their genomes: two in ORF1, one in ORF2, and two in ORF3. At both the nucleotide and amino acid levels, genome-based phylogenetic analyses invariably showed that the CBNU1 strain was most closely related to three GII.3 NoVs: the American Texas/TCH04-577 and the two Japanese Saitama U18 and Saitama U201 strains; furthermore, these genome-based phylogenetic topologies corresponded most closely to those based on the ORF2 genes, as compared to those based on the ORF1 and ORF3 genes. Subsequent ORF2-based phylogenetic analyses of a selection of 126 other NoVs representing all 19 GII genotypes, in combination with genome-based Simplot analyses, showed that the CBNU1 strain was a recombinant GII.3 NoV with a breakpoint at the ORF1/ORF2 junction between two putative parent-like strains, Guangzhou/NVgz01 and Texas/TCH04-577. Overall, the CBNU1 strain represents the first Korean human NoV whose genome has been completely sequenced and for which its relationship with a large panel of genetically diverse NoVs has been extensively characterized.
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Affiliation(s)
- Sang-Im Yun
- Department of Microbiology, College of Medicine and Medical Research Institute, Chungbuk National University, 12 Gaeshin-Dong, Heungduk-Ku, Cheongju, Chungbuk, South Korea
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41
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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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Someya Y, Takeda N. Insights into the enzyme-substrate interaction in the norovirus 3C-like protease. J Biochem 2009; 146:509-21. [PMID: 19556225 DOI: 10.1093/jb/mvp094] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Glu54 residue of the norovirus 3C-like protease was implicated in proteolysis as a third-member carboxylate of the catalytic triad. The E54L mutant protease cleaved the sequence (133)LSFE/AP between the 3B and 3C regions of norovirus polyprotein, but did not cleave the sequence (198)ATSE/GK between the 3A and 3B. The 3BC junction mutation (3B-L133A or 3B-F135S) hampered the cleavage by the E54L protease, whereas the 3AB junction mutation (3A-A198L, S200F) allowed the E54L protease to digest. These results indicate that the E54L mutant protease is a substrate-specificity mutant and requires large hydrophobic amino acid residues at both P4 and P2 positions of the substrate. It was notable that the 3A-S200F P2 position mutation caused tight interaction between the wild-type protease and the C-terminus of the 3A protein, hence a decreased release rate of the product from the enzyme. This tight binding was dependent on the hydrophobicity of amino acid residues introduced at position 200 of the 3A region and was affected by the mutation in the bII-cII loop of the protease or the mutation of position 198 of 3A corresponding to the P4 position of the substrate. These results suggest that the protease and the substrate sense each other in the process of the proteolysis, being supported by crystal structures.
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Affiliation(s)
- Yuichi Someya
- Department of Virology II, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashi-Murayama, Tokyo 208-0011, Japan.
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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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Yao L, Wu Q, Wang D, Kou X, Zhang J. Development of monoclonal antibody-coated immunomagnetic beads for separation and detection of norovirus (genogroup II) in faecal extract samples. Lett Appl Microbiol 2009; 49:173-8. [PMID: 19453950 DOI: 10.1111/j.1472-765x.2009.02638.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS The aim of this study is to develop an RT-PCR assay combined with immunomagnetic beads (IMS/RT-PCR) coating monoclonal antibody (Mab) for separation and detection of norovirus (genogroup II) in faecal samples. We furthermore compare its detection limits with IMS/RT-PCR using polyclonal antibody (Pab) and the TRIzol extraction method followed by RT-PCR (TRIzol-RT-PCR). METHODS AND RESULTS Mab-coated beads and Pab-coated beads were added to a series of tenfold dilutions of faecal extract containing norovirus in 1 ml PBS. After incubation and collection, the RNA was released by heating from virus separated by beads. The tenfold dilutions of faecal were also extracted with TRIzol reagent. The RNA was used as the template for RT-PCR detection (primers: JV12-JV13). IMS/RT-PCR using Mab showed an endpoint in the 10(-7) dilution and was 10(2) times more sensitive than IMS/RT-PCR using Pab and was at least 10(3) times more sensitive than TRIzol-RT-PCR method. CONCLUSIONS IMS/RT-PCR using Mab proved to be a more sensitive method of noroviruses (NVs) detection than IMS/RT-PCR using Pab and the TRIzol-RT-PCR method. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first study to detect NVs with IMS/RT-PCR using Mab, and could serve as a model for future assays when broadly reactive NVs-specific Mabs are developed.
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Affiliation(s)
- L Yao
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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Murine norovirus, a recently discovered and highly prevalent viral agent of mice. Lab Anim (NY) 2008; 37:314-20. [PMID: 18568010 DOI: 10.1038/laban0708-314] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Accepted: 01/30/2008] [Indexed: 11/08/2022]
Abstract
Murine norovirus (MNV), a recently discovered viral agent of laboratory mice, is closely related to human norovirus, a contagious pathogen known to cause gastroenteritis. The prototype strain of MNV (MNV-1) was first isolated and characterized in 2003 as a sporadic, lethal pathogen in certain strains of immunocompromised knockout mice. Serological surveillance data from mouse colonies throughout the US and Canada have since shown that MNV is highly prevalent. Because MNV is unique among norovirus strains in its ability to replicate in cell culture, it serves as the most accessible model to elucidate the mechanisms of infection and replication of human norovirus. The author discusses the genetic diversity of MNV, its prevalence, pathology and potential research implications, as well as techniques for detection and eradication of this virus.
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McCartney SA, Thackray LB, Gitlin L, Gilfillan S, Virgin HW, Virgin Iv HW, Colonna M. MDA-5 recognition of a murine norovirus. PLoS Pathog 2008; 4:e1000108. [PMID: 18636103 PMCID: PMC2443291 DOI: 10.1371/journal.ppat.1000108] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 06/20/2008] [Indexed: 12/21/2022] Open
Abstract
Noroviruses are important human pathogens responsible for most cases of viral epidemic gastroenteritis worldwide. Murine norovirus-1 (MNV-1) is one of several murine noroviruses isolated from research mouse facilities and has been used as a model of human norovirus infection. MNV-1 infection has been shown to require components of innate and adaptive immunity for clearance; however, the initial host protein that recognizes MNV-1 infection is unknown. Because noroviruses are RNA viruses, we investigated whether MDA5 and TLR3, cellular sensors that recognize dsRNA, are important for the host response to MNV-1. We demonstrate that MDA5−/− dendritic cells(DC) have a defect in cytokine response to MNV-1. In addition, MNV-1 replicates to higher levels in MDA5−/− DCs as well as in MDA5−/− mice in vivo. Interestingly, TLR3−/− DCs do not have a defect in vitro, but TLR3−/− mice have a slight increase in viral titers. This is the first demonstration of an innate immune sensor for norovirus and shows that MDA5 is required for the control of MNV-1 infection. Knowledge of the host response to MNV-1 may provide keys for prevention and treatment of the human disease. Gastroenteritis is a common disease in both developed and developing countries. The two main causes of this affliction are bacteria and viruses. The primary viruses implicated in gastroenteritis have been shown to be noroviruses, which include Norwalk virus, notorious for numerous recent outbreaks on cruise ships. We are interested in how the innate immune system detects viral infection and prepares the host to respond to the threat. To understand how the host responds to norovirus infection, we studied two classes of proteins, both of which are thought to detect signs of viral infection. We discovered that one of these proteins, melanoma differentiation associated protein-5 (MDA-5), is responsible for detecting a mouse norovirus that is genetically related to the human pathogen. These findings allow us to better understand the pathogenesis of norovirus infection and may provide clues for controlling the human disease.
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Affiliation(s)
- Stephen A McCartney
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
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Thackray LB, Wobus CE, Chachu KA, Liu B, Alegre ER, Henderson KS, Kelley ST, Virgin HW. Murine noroviruses comprising a single genogroup exhibit biological diversity despite limited sequence divergence. J Virol 2007; 81:10460-73. [PMID: 17652401 PMCID: PMC2045448 DOI: 10.1128/jvi.00783-07] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Viruses within the genus Norovirus of the family Caliciviridae are the major cause of acute, nonbacterial gastroenteritis worldwide. Human noroviruses are genetically diverse, with up to 57% divergence in capsid protein sequences, and comprise three genogroups. The significance of such genetic diversity is not yet understood. The discovery of murine norovirus (MNV) and its ability to productively infect cultured murine macrophages and dendritic cells has provided an opportunity to determine the functional consequences of norovirus diversity in vitro and in vivo. Therefore, we compared the full-length genomes of 21 new MNV isolates with five previously sequenced MNV genomes and demonstrated a conserved genomic organization consisting of four open reading frames (ORFs) and a previously unknown region of nucleotide conservation in ORF2. A phylogenetic analysis of all 26 MNV genomes revealed 15 distinct MNV strains, with up to 13% divergence at the nucleotide level, that comprise a single genotype and genogroup. Evidence for recombination within ORF2 in several MNV genomes was detected by multiple methods. Serological analyses comparing neutralizing antibody responses between highly divergent strains suggested that the MNV genogroup comprises a single serotype. Within this single genogroup, MNV strains exhibited considerable biological diversity in their ability to grow in culture and to infect and/or persist in wild-type mice. The isolation and characterization of multiple MNV strains illustrate how genetic analysis may underestimate the biological diversity of noroviruses and provide a molecular map for future studies of MNV biology.
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Affiliation(s)
- Larissa B Thackray
- 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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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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Ward VK, McCormick CJ, Clarke IN, Salim O, Wobus CE, Thackray LB, Virgin HW, Lambden PR. Recovery of infectious murine norovirus using pol II-driven expression of full-length cDNA. Proc Natl Acad Sci U S A 2007; 104:11050-5. [PMID: 17581883 PMCID: PMC1904157 DOI: 10.1073/pnas.0700336104] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Noroviruses are the major cause of nonbacterial gastroenteritis in humans. These viruses have remained refractory to detailed molecular studies because of the lack of a reverse genetics system coupled to a permissive cell line for targeted genetic manipulation. There is no permissive cell line in which to grow infectious human noroviruses nor an authentic animal model that supports their replication. In contrast, murine norovirus (MNV) offers a tractable system for the study of noroviruses with the recent discovery of permissive cells and a mouse model. The lack of a reverse genetic system for MNV has been a significant block to understanding the biology of noroviruses. We report recovery of infectious MNV after baculovirus delivery of viral cDNA to human hepatoma cells under the control of an inducible DNA polymerase (pol) II promoter. Recovered virus replicated in murine macrophage (RAW264.7) cells, and the recovery of MNV from DNA was confirmed through recovery of virus containing a marker mutation. This pol II promoter driven expression of viral cDNA also generated infectious virus after transfection of HEK293T cells, thus providing both transduction and transfection systems for norovirus reverse genetics. We used norovirus reverse genetics to demonstrate by mutagenesis of the protease-polymerase (pro-pol) cleavage site that processing of pro-pol is essential for the recovery of infectious MNV. This represents the first infectious reverse genetics system for a norovirus, and should provide approaches to address fundamental questions in norovirus molecular biology and replication.
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Affiliation(s)
- Vernon K Ward
- Department of Microbiology and Immunology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand.
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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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