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Marsili G, Acchioni C, Remoli AL, Amatore D, Sgarbanti R, De Angelis M, Orsatti R, Acchioni M, Astolfi A, Iraci N, Puzelli S, Facchini M, Perrotti E, Cecchetti V, Sabatini S, Superti F, Agamennone M, Barreca ML, Hiscott J, Nencioni L, Sgarbanti M. Identification of Anti-Influenza A Compounds Inhibiting the Viral Non-Structural Protein 1 (NS1) Using a Type I Interferon-Driven Screening Strategy. Int J Mol Sci 2023; 24:10495. [PMID: 37445672 DOI: 10.3390/ijms241310495] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 07/15/2023] Open
Abstract
There is an urgent need to identify efficient antiviral compounds to combat existing and emerging RNA virus infections, particularly those related to seasonal and pandemic influenza outbreaks. While inhibitors of the influenza viral integral membrane proton channel protein (M2), neuraminidase (NA), and cap-dependent endonuclease are available, circulating influenza viruses acquire resistance over time. Thus, the need for the development of additional anti-influenza drugs with novel mechanisms of action exists. In the present study, a cell-based screening assay and a small molecule library were used to screen for activities that antagonized influenza A non-structural protein 1 (NS1), a highly conserved, multifunctional accessory protein that inhibits the type I interferon response against influenza. Two potential anti-influenza agents, compounds 157 and 164, were identified with anti-NS1 activity, resulting in the reduction of A/PR/8/34(H1N1) influenza A virus replication and the restoration of IFN-β expression in human lung epithelial A549 cells. A 3D pharmacophore modeling study of the active compounds provided a glimpse of the structural motifs that may contribute to anti-influenza virus activity. This screening approach is amenable to a broader analysis of small molecule compounds to inhibit other viral targets.
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Affiliation(s)
- Giulia Marsili
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Chiara Acchioni
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Anna Lisa Remoli
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Donatella Amatore
- Department of Public Health and Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, 00185 Rome, Italy
| | - Rossella Sgarbanti
- Department of Public Health and Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, 00185 Rome, Italy
| | - Marta De Angelis
- Department of Public Health and Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, 00185 Rome, Italy
- Laboratory of Virology, Department of Molecular Medicine, Sapienza University of Rome, 00185 Rome, Italy
| | - Roberto Orsatti
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Marta Acchioni
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Andrea Astolfi
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Nunzio Iraci
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy
| | - Simona Puzelli
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Marzia Facchini
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Edvige Perrotti
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Violetta Cecchetti
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Stefano Sabatini
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - Fabiana Superti
- National Centre for Innovative Technologies in Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
| | - Mariangela Agamennone
- Department of Pharmacy, University "G. d'Annunzio" of Chieti-Pescara, Via dei Vestini 31, 66100 Chieti, Italy
| | - Maria Letizia Barreca
- Department of Pharmaceutical Sciences, Università degli Studi di Perugia, Via del Liceo 1, 06123 Perugia, Italy
| | - John Hiscott
- Istituto Pasteur Italia, Fondazione Cenci Bolognetti, Viale Regina Elena 291, 00161 Rome, Italy
| | - Lucia Nencioni
- Department of Public Health and Infectious Diseases, Laboratory Affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University, 00185 Rome, Italy
| | - Marco Sgarbanti
- Department of Infectious Diseases, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy
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Kelley EJ, Henson SN, Rahee F, Boyle AS, Engelbrektson AL, Nelson GA, Mead HL, Anderson NL, Razavi M, Yip R, Ladner JT, Scriba TJ, Altin JA. Virome-wide detection of natural infection events and the associated antibody dynamics using longitudinal highly-multiplexed serology. Nat Commun 2023; 14:1783. [PMID: 36997517 PMCID: PMC10062260 DOI: 10.1038/s41467-023-37378-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/07/2023] [Indexed: 04/03/2023] Open
Abstract
Current methods for detecting infections either require a sample collected from an actively infected site, are limited in the number of agents they can query, and/or yield no information on the immune response. Here we present an approach that uses temporally coordinated changes in highly-multiplexed antibody measurements from longitudinal blood samples to monitor infection events at sub-species resolution across the human virome. In a longitudinally-sampled cohort of South African adolescents representing >100 person-years, we identify >650 events across 48 virus species and observe strong epidemic effects, including high-incidence waves of Aichivirus A and the D68 subtype of Enterovirus D earlier than their widespread circulation was appreciated. In separate cohorts of adults who were sampled at higher frequency using self-collected dried blood spots, we show that such events temporally correlate with symptoms and transient inflammatory biomarker elevations, and observe the responding antibodies to persist for periods ranging from ≤1 week to >5 years. Our approach generates a rich view of viral/host dynamics, supporting novel studies in immunology and epidemiology.
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Affiliation(s)
- Erin J Kelley
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | - Sierra N Henson
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | - Fatima Rahee
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | - Annalee S Boyle
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | - Anna L Engelbrektson
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | - Georgia A Nelson
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | - Heather L Mead
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA
| | | | | | - Richard Yip
- SISCAPA Assay Technologies, Inc., Washington, DC, USA
| | - Jason T Ladner
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Thomas J Scriba
- South African Tuberculosis Vaccine Initiative and Institute of Infectious Disease and Molecular Medicine, Division of Immunology, Department of Pathology, University of Cape Town, Cape Town, South Africa
| | - John A Altin
- The Translational Genomics Research Institute (TGen), Flagstaff and Phoenix, AZ, USA.
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3
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Tseng YY, Kuan CY, Mibayashi M, Chen CJ, Palese P, Albrecht RA, Hsu WL. Interaction between NS1 and Cellular MAVS Contributes to NS1 Mitochondria Targeting. Viruses 2021; 13:1909. [PMID: 34696339 PMCID: PMC8537625 DOI: 10.3390/v13101909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 11/16/2022] Open
Abstract
Influenza A virus nonstructural protein 1 (NS1) plays an important role in evading host innate immunity. NS1 inhibits interferon (IFN) responses via multiple mechanisms, including sequestering dsRNA and suppressing retinoic acid-inducible gene I (RIG-I) signaling by interacting with RIG-I and tripartite motif-containing protein 25 (TRIM25). In the current study, we demonstrated the mitochondrial localization of NS1 at the early stage of influenza virus infection. Since NS1 does not contain mitochondria-targeting signals, we suspected that there is an association between the NS1 and mitochondrial proteins. This hypothesis was tested by demonstrating the interaction of NS1 with mitochondrial antiviral-signaling protein (MAVS) in a RIG-I-independent manner. Importantly, the association with MAVS facilitated the mitochondrial localization of NS1 and thereby significantly impeded MAVS-mediated Type I IFN production.
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Affiliation(s)
- Yeu-Yang Tseng
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 402, Taiwan; (Y.-Y.T.); (C.-Y.K.)
- WHO Collaborating Centre for Reference and Research on Influenza, Royal Melbourne Hospital, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC 3000, Australia
- Department of Infectious Diseases, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC 3000, Australia
| | - Chih-Ying Kuan
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 402, Taiwan; (Y.-Y.T.); (C.-Y.K.)
| | - Masaki Mibayashi
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.M.); (C.-J.C.); (P.P.); (R.A.A.)
| | - Chi-Jene Chen
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.M.); (C.-J.C.); (P.P.); (R.A.A.)
| | - Peter Palese
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.M.); (C.-J.C.); (P.P.); (R.A.A.)
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Randy A. Albrecht
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; (M.M.); (C.-J.C.); (P.P.); (R.A.A.)
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Wei-Li Hsu
- Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung 402, Taiwan; (Y.-Y.T.); (C.-Y.K.)
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Sreenivasan CC, Thomas M, Kaushik RS, Wang D, Li F. Influenza A in Bovine Species: A Narrative Literature Review. Viruses 2019; 11:v11060561. [PMID: 31213032 PMCID: PMC6631717 DOI: 10.3390/v11060561] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 12/17/2022] Open
Abstract
It is quite intriguing that bovines were largely unaffected by influenza A, even though most of the domesticated and wild animals/birds at the human-animal interface succumbed to infection over the past few decades. Influenza A occurs on a very infrequent basis in bovine species and hence bovines were not considered to be susceptible hosts for influenza until the emergence of influenza D. This review describes a multifaceted chronological review of literature on influenza in cattle which comprises mainly of the natural infections/outbreaks, experimental studies, and pathological and seroepidemiological aspects of influenza A that have occurred in the past. The review also sheds light on the bovine models used in vitro and in vivo for influenza-related studies over recent years. Despite a few natural cases in the mid-twentieth century and seroprevalence of human, swine, and avian influenza viruses in bovines, the evolution and host adaptation of influenza A virus (IAV) in this species suffered a serious hindrance until the novel influenza D virus (IDV) emerged recently in cattle across the world. Supposedly, certain bovine host factors, particularly some serum components and secretory proteins, were reported to have anti-influenza properties, which could be an attributing factor for the resilient nature of bovines to IAV. Further studies are needed to identify the host-specific factors contributing to the differential pathogenetic mechanisms and disease progression of IAV in bovines compared to other susceptible mammalian hosts.
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Affiliation(s)
- Chithra C Sreenivasan
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
| | - Milton Thomas
- Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD 57007, USA.
| | - Radhey S Kaushik
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
| | - Dan Wang
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
- BioSystems Networks and Translational Research Center (BioSNTR), Brookings, SD 57007, USA.
| | - Feng Li
- Department of Biology and Microbiology, South Dakota State University, Brookings, SD 57007, USA.
- BioSystems Networks and Translational Research Center (BioSNTR), Brookings, SD 57007, USA.
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5
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Tsai CF, Lin HY, Hsu WL, Tsai CH. The novel mitochondria localization of influenza A virus NS1 visualized by FlAsH labeling. FEBS Open Bio 2017; 7:1960-1971. [PMID: 29226082 PMCID: PMC5715299 DOI: 10.1002/2211-5463.12336] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/06/2017] [Accepted: 10/08/2017] [Indexed: 12/11/2022] Open
Abstract
The nonstructural protein 1 (NS1) of the influenza A virus (IAV) is a multifunctional protein that counteracts host cell antiviral responses and inhibits host cell pre‐mRNA processing. NS1 contains two nuclear localization signals that facilitate NS1 shuttling between cytoplasm and nucleus. In this study, we initially observed the novel mitochondria localization of NS1 in a subset of transfected cells. We then further monitored the localization dynamics of the NS1 protein in live cells infected with IAV expressing NS1 with insertion of a tetracysteine‐tag. The resulting mutant virus showed similar levels of infectivity and expression pattern of NS1 to those of wild‐type IAV. Pulse labeling using a biarsenical compound (fluorescein arsenical hairpin binder) allowed us to visualize the dynamic subcellular distribution of NS1 real time. We detected NS1 in mitochondria at a very early infection time point [1.5 h postinfection (hpi)] and observed the formation of a granular structure pattern in the nucleus at 4 hpi. This is the first identification of the novel mitochondria localization of NS1. The possible role of NS1 at an early infection time point is discussed.
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Affiliation(s)
- Chuan-Fu Tsai
- Graduate Institute of Biotechnology National Chung Hsing University Taichung Taiwan
| | - Hsin-Yi Lin
- Graduate Institute of Biotechnology National Chung Hsing University Taichung Taiwan
| | - Wei-Li Hsu
- Graduate Institute of Microbiology and Public Health National Chung Hsing University Taichung Taiwan
| | - Ching-Hsiu Tsai
- Graduate Institute of Biotechnology National Chung Hsing University Taichung Taiwan
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6
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Replication-Competent Influenza A and B Viruses Expressing a Fluorescent Dynamic Timer Protein for In Vitro and In Vivo Studies. PLoS One 2016; 11:e0147723. [PMID: 26809059 PMCID: PMC4725730 DOI: 10.1371/journal.pone.0147723] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/07/2016] [Indexed: 01/13/2023] Open
Abstract
Influenza A and B viruses (IAV and IBV, respectively) cause annual seasonal human respiratory disease epidemics. In addition, IAVs have been implicated in occasional pandemics with inordinate health and economic consequences. Studying influenza viruses in vitro or in vivo requires the use of laborious secondary methodologies to identify infected cells. To circumvent this requirement, replication-competent infectious influenza viruses expressing an easily traceable fluorescent reporter protein can be used. Timer is a fluorescent protein that undergoes a time-dependent color emission conversion from green to red. The rate of spectral change is independent of Timer protein concentration and can be used to chronologically measure the duration of its expression. Here, we describe the generation of replication-competent IAV and IBV where the viral non-structural protein 1 (NS1) was fused to the fluorescent dynamic Timer protein. Timer-expressing IAV and IBV displayed similar plaque phenotypes and growth kinetics to wild-type viruses in tissue culture. Within infected cells, Timer’s spectral shift can be used to measure the rate and cell-to-cell spread of infection using fluorescent microscopy, plate readers, or flow cytometry. The progression of Timer-expressing IAV infection was also evaluated in a mouse model, demonstrating the feasibility to characterize IAV cell-to-cell infections in vivo. By providing the ability to chronologically track viral spread, Timer-expressing influenza viruses are an excellent option to evaluate the in vitro and in vivo dynamics of viral infection.
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7
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Barnwal B, Mok CK, Wu J, Diwakar MK, Gupta G, Zeng Q, Chow VTK, Song J, Yuan YA, Tan YJ. A monoclonal antibody binds to threonine 49 in the non-structural 1 protein of influenza A virus and interferes with its ability to modulate viral replication. Antiviral Res 2015; 116:55-61. [PMID: 25666762 PMCID: PMC7113856 DOI: 10.1016/j.antiviral.2015.01.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 12/10/2014] [Accepted: 01/30/2015] [Indexed: 01/01/2023]
Abstract
The emergence of resistant influenza A viruses highlights the continuous requirement of new antiviral drugs that can treat the viral infection. Non-structural 1 (NS1) protein, an indispensable component for efficient virus replication, can be used as a potential target for generating new antiviral agents. Here, we study the interaction of 2H6 monoclonal antibody with NS1 protein and also determine whether influenza virus replication can be inhibited by blocking NS1. The 2H6-antigen binding fragment (Fab) forms a multimeric complex with the NS1 RNA-binding domain (RBD). T49, a residue which forms a direct hydrogen bond with double stranded RNA, in NS1 protein was found to be critical for its interaction with 2H6 antibody. NS1(RBD) has high affinity to 2H6 with KD of 43.5±4.24nM whereas NS1(RBD)-T49A has more than 250 times lower affinity towards 2H6. Interestingly, the intracellular expression of 2H6-single-chain variable fragment (scFv) in mammalian cells caused a reduction in viral growth and the M1 viral protein level was significantly reduced in 2H6-scFv transfected cells in comparison to vector transfected cells at 12h post infection. These results indicate that the tight binding of 2H6 to NS1 could lead to reduction in viral replication and release of progeny virus. In future, 2H6 antibody in combination with other neutralizing antibodies can be used to increase the potency of viral inhibition.
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Affiliation(s)
- Bhaskar Barnwal
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Chee-Keng Mok
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Jianping Wu
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Mandakhalikar Kedar Diwakar
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Garvita Gupta
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Qi Zeng
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore
| | - Vincent Tak Kwong Chow
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore
| | - Jianxing Song
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Y Adam Yuan
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore; National University of Singapore (Suzhou) Research Institute, Suzhou Industrial Park, Jiangsu 215123, China
| | - Yee-Joo Tan
- Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System (NUHS), National University of Singapore, Singapore; Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore.
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Abstract
The non-structural protein 1 of influenza virus (NS1) is a relatively small polypeptide with an outstanding number of ascribed functions. NS1 is the main viral antagonist of the innate immune response during influenza virus infection, chiefly by inhibiting the type I interferon system at multiple steps. As such, its role is critical to overcome the first barrier the host presents to halt the viral infection. However, the pro-viral activities of this well-studied protein go far beyond and include regulation of viral RNA and protein synthesis, and disruption of the host cell homeostasis by dramatically affecting general gene expression while tweaking the PI3K signaling network. Because of all of this, NS1 is a key virulence factor that impacts influenza pathogenesis, and adaptation to new hosts, making it an attractive target for control strategies. Here, we will overview the many roles that have been ascribed to the NS1 protein, and give insights into the sequence features and structural properties that make them possible, highlighting the need to understand how NS1 can actually perform all of these functions during viral infection.
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Affiliation(s)
- Juan Ayllon
- Department of Microbiology, Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
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Talazadeh F, Mayahi M, Seifi M, Pourmehdi M. Evaluation of a commercial ELISA kit (IDEXX) to differentiate AI virus-infected poultry from AI-vaccinated poultry (DIVA). BRAZILIAN JOURNAL OF POULTRY SCIENCE 2014. [DOI: 10.1590/1516-635x160273-78] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - M Mayahi
- Shahid Chamran University of Ahvaz, Iran
| | - M Seifi
- Shahid Chamran University of Ahvaz, Iran
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10
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Xu J, Zhong HA, Madrahimov A, Helikar T, Lu G. Molecular phylogeny and evolutionary dynamics of influenza A nonstructural (NS) gene. INFECTION GENETICS AND EVOLUTION 2014; 22:192-200. [DOI: 10.1016/j.meegid.2013.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 10/01/2013] [Accepted: 10/14/2013] [Indexed: 01/23/2023]
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11
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Othumpangat S, Noti JD, Blachere FM, Beezhold DH. Expression of non-structural-1A binding protein in lung epithelial cells is modulated by miRNA-548an on exposure to influenza A virus. Virology 2013; 447:84-94. [PMID: 24210102 DOI: 10.1016/j.virol.2013.08.031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 06/29/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
Abstract
Understanding the host response to influenza A virus infection is essential for developing intervention approaches. We show that infection of human alveolar epithelial cells and human bronchial epithelial cells with influenza A for 3h resulted in down-regulation of host hsa-miRNA-548an (miRNA-548an) which triggered the overexpression of influenza non-structural-1A binding protein (IVNS1ABP, herein referred to as NS1ABP). Reduced NS1ABP mRNA and NS1ABP protein expression after transfection of miRNA-548an mimic or increased NS1ABP mRNA and NS1ABP protein expression after transfection of miRNA-548an inhibitor provided evidence that miRNA-548an is involved in the regulation of NS1ABP. Transfection of cells with inhibitor led to reduced apoptosis of infected cells while transfection of mimic led to increased apoptosis and reduced influenza copy number suggesting that NS1ABP has a role in viral maintenance. Thus, miRNA-548an may be an important target in controlling the early stage infection of influenza A.
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Affiliation(s)
- Sreekumar Othumpangat
- Allergy and Clinical Immunology Branch, Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505-2888, USA
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12
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Xie Z, Luo S, Fan Q, Xie L, Liu J, Xie Z, Pang Y, Deng X, Wang X. Detection of antibodies specific to the non-structural proteins of fowl adenoviruses in infected chickens but not in vaccinated chickens. Avian Pathol 2013; 42:491-6. [PMID: 24024561 DOI: 10.1080/03079457.2013.829553] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Antibodies specific to the non-structural proteins of viruses are detected in virus-infected animals and show promise as a reliable diagnostic marker for virus infections. We examined the potential use of two non-structural proteins of fowl adenovirus (FAdV)-based, 100K and 33K, enzyme-linked immunosorbent assays (ELISAs) in the diagnosis of FAdVs. We cloned and expressed the 100K and 33K non-structural protein genes of the FAdVs in the pGEX-4T-1 plasmid vector. Purified 100K and 33K proteins alone or in combination were used as antigens in ELISAs. Antibodies specific to the 100K and 33K non-structural proteins were detected in chickens experimentally infected with FAdVs, but not in chickens vaccinated with inactivated FAdVs. In contrast, the agar gel precipitation (AGP) test detected FAdV-specific antibodies in 70.3% of the vaccinated chickens, suggesting that the non-structural protein-based ELISA could be used in the differential diagnosis of infected and vaccinated chickens. To further validate the 100K and 33K-based ELISA (100K-33K-ELISA) method, we compared its sensitivity and specificity with that of a whole virus-based ELISA and an AGP test in detecting FAdV-specific antibodies in 350 field samples. The results showed that the 100K-33K-ELISA exhibited a higher sensitivity than the AGP test and a comparable sensitivity and specificity to the whole virus ELISA. Overall, the 100K-33K-ELISA method is sensitive, specific and can be used to distinguish an acute FAdV infection from an inactivated virus-based vaccination response.
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Affiliation(s)
- Zhixun Xie
- a Department of Biotechnology , Guangxi Veterinary Research Institute , Nanning , Guangxi , China
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13
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Survey on ELISA Based on anti Influenza A NS1 Antibodies to Differentiate the Infected and Vaccinated Poultries. Jundishapur J Microbiol 2013. [DOI: 10.5812/jjm.7055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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14
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Preparation of monoclonal antibodies against poor immunogenic avian influenza virus proteins. J Immunol Methods 2013; 387:43-50. [DOI: 10.1016/j.jim.2012.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/05/2012] [Accepted: 09/19/2012] [Indexed: 11/21/2022]
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15
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Rahim MN, Selman M, Sauder PJ, Forbes NE, Stecho W, Xu W, Lebar M, Brown EG, Coombs KM. Generation and characterization of a new panel of broadly reactive anti-NS1 mAbs for detection of influenza A virus. J Gen Virol 2012; 94:593-605. [PMID: 23223621 DOI: 10.1099/vir.0.046649-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Influenza A virus (IAV) non-structural protein 1 (NS1) has multiple functions, is essential for virus replication and may be a good target for IAV diagnosis. To generate broadly cross-reactive NS1-specific mAbs, mice were immunized with A/Hong Kong/1/1968 (H3N2) 6×His-tagged NS1 and hybridomas were screened with glutathione S-transferase-conjugated NS1 of A/Puerto Rico/8/1934 (H1N1). mAbs were isotyped and numerous IgG-type clones were characterized further. Most clones specifically recognized NS1 from various H1N1 and H3N2 IAV types by both immunoblot and immunofluorescence microscopy in mouse M1, canine Madin-Darby canine kidney and human A549 cells. mAb epitopes were mapped by overlapping peptides and selective reactivity to the newly described viral NS3 protein. These mAbs detected NS1 in both the cytoplasm and nucleus by immunostaining, and some detected NS1 as early as 5 h post-infection, suggesting their potential diagnostic use for tracking productive IAV replication and characterizing NS1 structure and function. It was also demonstrated that the newly identified NS3 protein is localized in the cytoplasm to high levels.
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Affiliation(s)
- Md Niaz Rahim
- Manitoba Centre for Proteomics and Systems Biology, Room 799, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada.,Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J6, Canada
| | - Mohammed Selman
- Emerging Pathogens Research Centre, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Patricia J Sauder
- Manitoba Centre for Proteomics and Systems Biology, Room 799, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada
| | - Nicole E Forbes
- Emerging Pathogens Research Centre, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - William Stecho
- Emerging Pathogens Research Centre, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Wanhong Xu
- Manitoba Centre for Proteomics and Systems Biology, Room 799, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada.,Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J6, Canada
| | - Mark Lebar
- Manitoba Centre for Proteomics and Systems Biology, Room 799, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada.,Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J6, Canada
| | - Earl G Brown
- Emerging Pathogens Research Centre, University of Ottawa, Ottawa, ON K1H 8M5, Canada.,Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Kevin M Coombs
- Manitoba Institute of Child Health, Room 513, John Buhler Research Centre, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada.,Manitoba Centre for Proteomics and Systems Biology, Room 799, 715 McDermot Avenue, Winnipeg, MB R3E 3P4, Canada.,Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, MB R3E 0J6, Canada
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Richards KA, Chaves FA, Alam S, Sant AJ. Trivalent inactivated influenza vaccines induce broad immunological reactivity to both internal virion components and influenza surface proteins. Vaccine 2012; 31:219-25. [PMID: 23099328 DOI: 10.1016/j.vaccine.2012.10.039] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 08/29/2012] [Accepted: 10/10/2012] [Indexed: 01/18/2023]
Abstract
There are a number of related goals of influenza vaccination, including elicitation of protective antibodies and induction of cellular CD4 and CD8+ T cell responses. Because CD4+ T cell expansion and functionality are influenced by peptide specificity and T cell gene expression can be modified by repeated re-stimulations, it is important to evaluate how frequent influenza vaccinations affect CD4+ T cell dependent functions in protective immunity to influenza. Trivalent influenza vaccines (TIV) have production of neutralizing antibodies to HA as their primary goal and main criteria for efficacy. Accordingly, they are not characterized for any other viral components. In the current study, we evaluated whether other influenza virus proteins were present in commercial TIV at levels sufficient for immunogenicity in vivo. Mice that differed with regard to their expressed class II molecules were used in concert with peptide-stimulated cytokine ELISPOT assays to comprehensively evaluate the CD4+ T cell antigen specificity induced by the TIV. Our studies revealed that NA, NP, M1 and NS1 were present in sufficient quantities in the TIV to prime and boost CD4+ T cells. These results suggest that in humans, the broad CD4+ T cell repertoire induced by live infection is continually boosted and maintained throughout life by regular vaccination with licensed intramuscular split vaccines. The implications raised by our findings on CD4+ T cell functionality in influenza are discussed.
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Affiliation(s)
- Katherine A Richards
- David H. Smith Center for Vaccine Biology and Immunology, Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, United States
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17
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Emami T, Madani R, Rezayat S, Golchinfar F, Sarkar S. Applying of gold nanoparticle to avoid diffusion of the conserved peptide of avian influenza nonstructural protein from membrane in Western blot. J APPL POULTRY RES 2012. [DOI: 10.3382/japr.2011-00456] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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18
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Wang L, Qin Z, Pantin-Jackwood M, Faulkner O, Suarez DL, Garcia M, Lupiani B, Reddy SM, Saif YM, Lee CW. Development of DIVA (differentiation of infected from vaccinated animals) vaccines utilizing heterologous NA and NS1 protein strategies for the control of triple reassortant H3N2 influenza in turkeys. Vaccine 2011; 29:7966-74. [PMID: 21907751 DOI: 10.1016/j.vaccine.2011.08.067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 08/01/2011] [Accepted: 08/14/2011] [Indexed: 02/07/2023]
Abstract
Since 2003, triple reassortant (TR) swine H3N2 influenza viruses containing gene segments from human, avian, and swine origins have been detected in the U.S. turkey populations. The initial outbreak that occurred involved birds that were vaccinated with the currently available H3 swine- and avian-origin influenza vaccines. Antigenically, all turkey swine-lineage TR H3N2 isolates are closely related to each other but show little or no antigenic cross-reactivity with the avian origin or swine origin influenza vaccine strains that are currently being used in turkey operations. These results call for re-evaluation of currently available influenza vaccines being used in turkey flocks and development of more effective DIVA (differentiation of infected from vaccinated animals) vaccines. In this study, we selected one TR H3N2 strain, A/turkey/OH/313053/04 (H3N2) that showed broad cross reactivity with other recent TR turkey H3N2 isolates, and created NA- and NS-based DIVA vaccines using traditional reassortment as well as reverse genetics methods. Protective efficacy of those vaccines was determined in 2-week-old and 80-week-old breeder turkeys. The reassortant DIVA vaccines significantly reduced the presence of challenge virus in the oviduct of breeder turkeys as well as trachea and cloaca shedding of both young and old breeder turkeys, suggesting that proper vaccination could effectively prevent egg production drop and potential viral contamination of eggs in infected turkeys. Our results demonstrate that the heterologous NA and NS1 DIVA vaccines together with their corresponding serological tests could be useful for the control of TR H3N2 influenza in turkeys.
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Affiliation(s)
- Leyi Wang
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
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19
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Chemical inhibition of RNA viruses reveals REDD1 as a host defense factor. Nat Chem Biol 2011; 7:712-9. [PMID: 21909097 DOI: 10.1038/nchembio.645] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/01/2011] [Indexed: 11/09/2022]
Abstract
A chemical genetics approach was taken to identify inhibitors of NS1, a major influenza A virus virulence factor that inhibits host gene expression. A high-throughput screen of 200,000 synthetic compounds identified small molecules that reversed NS1-mediated inhibition of host gene expression. A counterscreen for suppression of influenza virus cytotoxicity identified naphthalimides that inhibited replication of influenza virus and vesicular stomatitis virus (VSV). The mechanism of action occurs through activation of REDD1 expression and concomitant inhibition of mammalian target of rapamycin complex 1 (mTORC1) via TSC1-TSC2 complex. The antiviral activity of naphthalimides was abolished in REDD1(-/-) cells. Inhibition of REDD1 expression by viruses resulted in activation of the mTORC1 pathway. REDD1(-/-) cells prematurely upregulated viral proteins via mTORC1 activation and were permissive to virus replication. In contrast, cells conditionally expressing high concentrations of REDD1 downregulated the amount of viral protein. Thus, REDD1 is a new host defense factor, and chemical activation of REDD1 expression represents a potent antiviral intervention strategy.
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20
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Takeyama N, Minari K, Kajihara M, Isoda N, Sakamoto R, Sasaki T, Kokumai N, Takikawa N, Shiraishi R, Mase M, Hagiwara J, Kodama T, Imamura T, Sakaguchi M, Ohgitani T, Sawata A, Okamatsu M, Muramatsu M, Tsukamoto K, Lin Z, Tuchiya K, Sakoda Y, Kida H. Detection of highly pathogenic avian influenza virus infection in vaccinated chicken flocks by monitoring antibodies against non-structural protein 1 (NS1). Vet Microbiol 2011; 147:283-91. [DOI: 10.1016/j.vetmic.2010.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/21/2010] [Accepted: 07/01/2010] [Indexed: 11/29/2022]
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21
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Yángüez E, Nieto A. So similar, yet so different: selective translation of capped and polyadenylated viral mRNAs in the influenza virus infected cell. Virus Res 2010; 156:1-12. [PMID: 21195735 DOI: 10.1016/j.virusres.2010.12.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 12/22/2010] [Accepted: 12/22/2010] [Indexed: 02/05/2023]
Abstract
Influenza virus is included among the Orthomyxoviridae family and it is a major public health problem causing annual mortality worldwide. Viral mRNAs bear short capped oligonucleotide sequences at their 5'-ends, acquired from host cell pre-mRNAs during viral transcription, and are polyadenylated at their 3'-end. Therefore, viral and cellular mRNAs are undistinguishable from a structural point of view. However, selective translation of viral proteins occurs upon infection, while initiation and elongation steps of cellular mRNA translation are efficiently inhibited. Viruses do not possess the complex machinery required to translate their mRNAs and are then obliged to compete for host-cell factors and manipulate the translation apparatus to their own benefit. Thus, the understanding of the processes that govern viral translation could facilitate the finding of possible targets for anti viral interventions. In the present review, we will point out the mechanisms by which influenza virus takes control of the host-cell protein synthesis machinery to ensure the production of new viral particles. First, we will discuss the mechanisms by which the virus counteracts the anti viral translation repression induced in the infected cell. Next, we will focus on the shut-off of cellular protein synthesis and the specific requirements for the eIF4F complex on influenza mRNA translation. Finally, we will discuss the role of different cellular and viral proteins in the selective translation of viral messengers in the infected cell and we will summarize the proposed mechanisms for the recruitment of cellular translational machinery to the viral mRNAs.
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Affiliation(s)
- Emilio Yángüez
- Centro Nacional de Biotecnología, C.S.I.C., Darwin 3, Cantoblanco, 28049 Madrid, Spain
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22
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Emmott E, Wise H, Loucaides EM, Matthews DA, Digard P, Hiscox JA. Quantitative proteomics using SILAC coupled to LC-MS/MS reveals changes in the nucleolar proteome in influenza A virus-infected cells. J Proteome Res 2010; 9:5335-45. [PMID: 20701360 DOI: 10.1021/pr100593g] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Influenza A virus (IAV) is a major human pathogen whose genotypic diversity results in unpredictable pandemics and epidemics. Interaction with the cell nucleus is essential to IAV infection, allowing recruitment of cellular components to facilitate virus replication. Viral proteins are also targeted to the nucleolus, a subnuclear structure involved in ribosomal biogenesis, RNA maturation, stress response, and control of cell growth, but the functional consequences of this are unclear. We took an unbiased approach to studying IAV-nucleolar interactions by using stable isotope labeling with amino acids in cell culture (SILAC) in conjunction with LC-MS/MS to quantify changes in the nucleolar proteome following infection with A/PR/8/34 (H1N1) and A/Udorn/72 (H3N2) strains of the virus. Only a minority of nucleolar proteins showed significant changes in abundance after infection; these alterations were mostly different between the two strains but could be validated by confocal microscopy of infected cells. Many of the affected proteins comprised functional groupings, including components of ribonuclease P, RNA polymerase I, the MLL1 histone methyltransferase complex, as well as nuclear paraspeckles and the RNA editing apparatus. This, as well as comparison with other viruses that cause changes in the nucleolar proteome, suggests that IAV targets specific nucleolar pathways.
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Affiliation(s)
- Edward Emmott
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom
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23
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Xie Z, Qin C, Xie L, Liu J, Pang Y, Deng X, Xie Z, Khan MI. Recombinant protein-based ELISA for detection and differentiation of antibodies against avian reovirus in vaccinated and non-vaccinated chickens. J Virol Methods 2010; 165:108-11. [DOI: 10.1016/j.jviromet.2009.12.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 12/08/2009] [Accepted: 12/10/2009] [Indexed: 10/20/2022]
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24
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Rai M, Bhatia S, Malik Y, Dubey S. Production and Characterization of Monoclonal Antibodies Against NS1 Protein of H5N1 Avian Influenza Virus. Hybridoma (Larchmt) 2010; 29:183-6. [DOI: 10.1089/hyb.2009.0080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Mohita Rai
- Biotechnology Centre, Jawahar Lal Nehru Krishi Vishwa Vidyalaya, Jabalpur, Madhya Pradesh, India
| | - Sandeep Bhatia
- High Security Animal Disease Laboratory, Indian Veterinary Research Institute, Anandnagar, Bhopal, Madhya Pradesh, India
| | - Y.P.S. Malik
- Biotechnology Centre, Jawahar Lal Nehru Krishi Vishwa Vidyalaya, Jabalpur, Madhya Pradesh, India
- Present address, Division of Virology, Indian Veterinary Research Institute, Mukteswar-Kumaon, Nainital, Uttaranchal, India
| | - S.C. Dubey
- High Security Animal Disease Laboratory, Indian Veterinary Research Institute, Anandnagar, Bhopal, Madhya Pradesh, India
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25
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Tan Z, Akerstrom S, Wee BY, Lal SK, Mirazimi A, Tan YJ. A new panel of NS1 antibodies for easy detection and titration of influenza A virus. J Med Virol 2010; 82:467-75. [PMID: 20087939 DOI: 10.1002/jmv.21709] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The non-structural protein NS1 of the influenza A virus is a good target for the development of diagnostic assays. In this study, three NS1 monoclonal antibodies (mAbs) were generated by using recombinant NS1 protein of H5N1 virus and found to bind both the native and denatured forms of NS1. Two of the mAbs, 6A4 and 2H6, bind NS1 of three different strains of influenza A virus, namely H1N1, H3N2, and H5N1. Epitope mapping revealed that residues 42-53 of H5N1 NS1 are essential for the interaction with both mAbs. Between the three strains, there is only one amino acid difference in this domain, which is consistent with the observed cross-reactivities. On the other hand, mAb 1G1 binds to residues 206-215 of H5N1 NS1 and does not bind NS1 of H1N1 or H3N2. Furthermore, all three mAbs detected NS1 proteins expressed in virus infected MDCK cells and indirect immunofluorescence staining with mAbs 6A4 and 2H6 provided an alternative method for viral titer determination. Quantifying the numbers of fluorescent foci units yielded viral titers for three different isolates of H5N1 virus that are highly comparable to that obtained by observing cytopathic effect induced by virus infection. Importantly, this alternative method yields results at 1 day post-infection while the conventional method using cytopathic effect yields results at 3 days post-infection. The results showed that this new panel of NS1 antibodies can detect NS1 protein expressed during viral infection and can be used for fast and easy titration of influenza A virus. J. Med. Virol. 82:467-475, 2010. (c) 2010 Wiley-Liss, Inc.
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Affiliation(s)
- Zhihao Tan
- Collaborative Anti-Viral Research Group, Institute of Molecular and Cell Biology, Singapore, Singapore
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26
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Hale BG, Randall RE, Ortín J, Jackson D. The multifunctional NS1 protein of influenza A viruses. J Gen Virol 2008; 89:2359-2376. [PMID: 18796704 DOI: 10.1099/vir.0.2008/004606-0] [Citation(s) in RCA: 818] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The non-structural (NS1) protein of influenza A viruses is a non-essential virulence factor that has multiple accessory functions during viral infection. In recent years, the major role ascribed to NS1 has been its inhibition of host immune responses, especially the limitation of both interferon (IFN) production and the antiviral effects of IFN-induced proteins, such as dsRNA-dependent protein kinase R (PKR) and 2'5'-oligoadenylate synthetase (OAS)/RNase L. However, it is clear that NS1 also acts directly to modulate other important aspects of the virus replication cycle, including viral RNA replication, viral protein synthesis, and general host-cell physiology. Here, we review the current literature on this remarkably multifunctional viral protein. In the first part of this article, we summarize the basic biochemistry of NS1, in particular its synthesis, structure, and intracellular localization. We then discuss the various roles NS1 has in regulating viral replication mechanisms, host innate/adaptive immune responses, and cellular signalling pathways. We focus on the NS1-RNA and NS1-protein interactions that are fundamental to these processes, and highlight apparent strain-specific ways in which different NS1 proteins may act. In this regard, the contributions of certain NS1 functions to the pathogenicity of human and animal influenza A viruses are also discussed. Finally, we outline practical applications that future studies on NS1 may lead to, including the rational design and manufacture of influenza vaccines, the development of novel antiviral drugs, and the use of oncolytic influenza A viruses as potential anti-cancer agents.
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Affiliation(s)
- Benjamin G Hale
- Centre for Biomolecular Sciences, University of St Andrews, St Andrews, Fife KY16 9ST, UK
| | - Richard E Randall
- Centre for Biomolecular Sciences, University of St Andrews, St Andrews, Fife KY16 9ST, UK
| | - Juan Ortín
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - David Jackson
- Centre for Biomolecular Sciences, University of St Andrews, St Andrews, Fife KY16 9ST, UK
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27
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Wang L, Suarez DL, Pantin-Jackwood M, Mibayashi M, García-Sastre A, Saif YM, Lee CW. Characterization of influenza virus variants with different sizes of the non-structural (NS) genes and their potential as a live influenza vaccine in poultry. Vaccine 2008; 26:3580-6. [PMID: 18539366 PMCID: PMC2785844 DOI: 10.1016/j.vaccine.2008.05.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 04/28/2008] [Accepted: 05/01/2008] [Indexed: 02/07/2023]
Abstract
From a stock of A/turkey/Oregon/71-delNS1 (H7N3) virus, which has a 10 nucleotide deletion in the coding region of the NS1 gene, we found that several variants with different sizes of NS genes could be produced by passaging the virus in 10- and 14-day-old embryonating chicken eggs (ECE), but not in 7-day-old ECE or Vero cells. We were able to rescue the reassortant virus that has different sizes of the NS genes and confirmed that those NS genes are genetically stable. By conducting in vivo studies in 2-week-old chickens, we found two plaque purified variants (D-del pc3 and pc4) which can be used as a potential live-attenuated vaccine. The variants were highly attenuated in chickens and did not transmit the virus from infected chickens to uninoculated cage mates. At the same time, the variants induced relatively high antibody titers which conferred good protection against a high dose heterologous virus challenge. Our study indicates that naturally selected NS1 deletion variants might be useful in the development of live-attenuated influenza vaccines in poultry. Furthermore, deletion in the NS1 protein can be potentially useful as a negative marker for a differentiating infected from vaccinated animals (DIVA) approach.
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Affiliation(s)
- L. Wang
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210
| | - D. L. Suarez
- Southeast Poultry Research Laboratory, USDA-ARS, Athens, Georgia 30605
| | | | - M. Mibayashi
- Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029
| | - A. García-Sastre
- Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029
- Department of Medicine, Division of Infection Diseases, Mount Sinai School of Medicine, New York, New York 10029
- Emerging Pathogens Institute, Mount Sinai School of Medicine, New York, New York 10029
| | - Y. M. Saif
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210
| | - C-W. Lee
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio 44691
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210
- Corresponding author. Food Animal Health Research Program, Ohio Agricultural Research and Development Center, 1680 Madison Avenue, Wooster, Ohio 44691. Phone: (330)2633750. Fax: (330)2633677.
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28
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Garaigorta U, Falcón AM, Ortín J. Genetic analysis of influenza virus NS1 gene: a temperature-sensitive mutant shows defective formation of virus particles. J Virol 2006; 79:15246-57. [PMID: 16306596 PMCID: PMC1316024 DOI: 10.1128/jvi.79.24.15246-15257.2005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To perform a genetic analysis of the influenza A virus NS1 gene, a library of NS1 mutants was generated by PCR-mediated mutagenesis. A collection of mutant ribonucleic proteins containing the nonstructural genes was generated from the library that were rescued for an infectious virus mutant library by a novel RNP competition virus rescue procedure. Several temperature-sensitive (ts) mutant viruses were obtained by screening of the mutant library, and the sequences of their NS1 genes were determined. Most of the mutations identified led to amino acid exchanges and concentrated in the N-terminal region of the protein, but some of them occurred in the C-terminal region. Mutant 11C contained three mutations that led to amino acid exchanges, V18A, R44K, and S195P, all of which were required for the ts phenotype, and was characterized further. Several steps in the infection were slightly altered: (i) M1, M2, NS1, and neuraminidase (NA) accumulations were reduced and (ii) NS1 protein was retained in the nucleus in a temperature-independent manner, but these modifications could not justify the strong virus titer reduction at restrictive temperature. The most dramatic phenotype was the almost complete absence of virus particles in the culture medium, in spite of normal accumulation and nucleocytoplasmic export of virus RNPs. The function affected in the 11C mutant was required late in the infection, as documented by shift-up and shift-down experiments. The defect in virion production was not due to reduced NA expression, as virus yield could not be rescued by exogenous neuraminidase treatment. All together, the analysis of 11C mutant phenotype may indicate a role for NS1 protein in a late event in virus morphogenesis.
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Affiliation(s)
- Urtzi Garaigorta
- Centro Nacional de Biotecnología (CSIC), Darwin 3, Cantoblanco, 28049 Madrid, Spain
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29
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Tumpey TM, Alvarez R, Swayne DE, Suarez DL. Diagnostic approach for differentiating infected from vaccinated poultry on the basis of antibodies to NS1, the nonstructural protein of influenza A virus. J Clin Microbiol 2005; 43:676-83. [PMID: 15695663 PMCID: PMC548100 DOI: 10.1128/jcm.43.2.676-683.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Vaccination programs for the control of avian influenza (AI) in poultry have limitations due to the problem of differentiating between vaccinated and virus-infected birds. We have used NS1, the conserved nonstructural protein of influenza A virus, as a differential diagnostic marker for influenza virus infection. Experimentally infected poultry were evaluated for the ability to induce antibodies reactive to NS1 recombinant protein produced in Escherichia coli or to chemically synthesized NS1 peptides. Immune sera were obtained from chickens and turkeys inoculated with live AI virus, inactivated purified vaccines, or inactivated commercial vaccines. Seroconversion to positivity for antibodies to the NS1 protein was achieved in birds experimentally infected with multiple subtypes of influenza A virus, as determined by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. In contrast, animals inoculated with inactivated gradient-purified vaccines had no seroconversion to positivity for antibodies to the NS1 protein, and animals vaccinated with commercial vaccines had low, but detectable, levels of NS1 antibodies. The use of a second ELISA with diluted sera identified a diagnostic test that results in seropositivity for antibodies to the NS1 protein only in infected birds. For the field application phase of this study, serum samples were collected from vaccinated and infected poultry, diluted, and screened for anti-NS1 antibodies. Field sera from poultry that received commercial AI vaccines were found to possess antibodies against AI virus, as measured by the standard agar gel precipitin (AGP) test, but they were negative by the NS1 ELISA. Conversely, diluted field sera from AI-infected poultry were positive for both AGP and NS1 antibodies. These results demonstrate the potential benefit of a simple, specific ELISA for anti-NS1 antibodies that may have diagnostic value for the poultry industries.
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Affiliation(s)
- Terrence M Tumpey
- Southwest Poultry Research Laboratory, Agricultural Research Service, US Department of Agriculture, College of Veterinary Medicine, University of Georgia, Athens, Georgia.
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30
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Falcón AM, Marión RM, Zürcher T, Gómez P, Portela A, Nieto A, Ortín J. Defective RNA replication and late gene expression in temperature-sensitive influenza viruses expressing deleted forms of the NS1 protein. J Virol 2004; 78:3880-8. [PMID: 15047804 PMCID: PMC374278 DOI: 10.1128/jvi.78.8.3880-3888.2004] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza A virus mutants expressing C-terminally deleted forms of the NS1 protein (NS1-81 and NS1-110) were generated by plasmid rescue. These viruses were temperature sensitive and showed a small plaque size at the permissive temperature. The accumulation of virion RNA in mutant virus-infected cells was reduced at the restrictive temperature, while the accumulation of cRNA or mRNA was not affected, indicating that the NS1 protein is involved in the control of transcription versus replication processes in the infection. The synthesis and accumulation of late virus proteins were reduced in NS1-81 mutant-infected cells at the permissive temperature and were essentially abolished for both viruses at the restrictive temperature, while synthesis and accumulation of nucleoprotein (NP) were unaffected. Probably as a consequence, the nucleocytoplasmic export of virus NP was strongly inhibited at the restrictive temperature. These results indicate that the NS1 protein is essential for nuclear and cytoplasmic steps during the virus cycle.
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Affiliation(s)
- Ana M Falcón
- Centro Nacional de Biotecnología, CSIC, 28049 Madrid, Spain
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Burgui I, Aragón T, Ortín J, Nieto A. PABP1 and eIF4GI associate with influenza virus NS1 protein in viral mRNA translation initiation complexes. J Gen Virol 2004; 84:3263-3274. [PMID: 14645908 DOI: 10.1099/vir.0.19487-0] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
It has previously been shown that influenza virus NS1 protein enhances the translation of viral but not cellular mRNAs. This enhancement occurs by increasing the rate of translation initiation and requires the 5'UTR sequence, common to all viral mRNAs. In agreement with these findings, we show here that viral mRNAs, but not cellular mRNAs, are associated with NS1 during virus infection. We have previously reported that NS1 interacts with the translation initiation factor eIF4GI, next to its poly(A)-binding protein 1 (PABP1)-interacting domain and that NS1 and eIF4GI are associated in influenza virus-infected cells. Here we show that NS1, although capable of binding poly(A), does not compete with PABP1 for association with eIF4GI and, furthermore, that NS1 and PABP1 interact both in vivo and in vitro in an RNA-independent manner. The interaction maps between residues 365 and 535 in PABP1 and between residues 1 and 81 in NS1. These mapping studies, together with those previously reported for NS1-eIF4GI and PABP1-eIF4GI interactions, imply that the binding of all three proteins would be compatible. Collectively, these and previously published data suggest that NS1 interactions with eIF4GI and PABP1, as well as with viral mRNAs, could promote the specific recruitment of 43S complexes to the viral mRNAs.
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Affiliation(s)
- Idoia Burgui
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Tomás Aragón
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Juan Ortín
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Amelia Nieto
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
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32
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Aragón T, de la Luna S, Novoa I, Carrasco L, Ortín J, Nieto A. Eukaryotic translation initiation factor 4GI is a cellular target for NS1 protein, a translational activator of influenza virus. Mol Cell Biol 2000; 20:6259-68. [PMID: 10938102 PMCID: PMC86100 DOI: 10.1128/mcb.20.17.6259-6268.2000] [Citation(s) in RCA: 166] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Influenza virus NS1 protein is an RNA-binding protein whose expression alters several posttranscriptional regulatory processes, like polyadenylation, splicing, and nucleocytoplasmic transport of cellular mRNAs. In addition, NS1 protein enhances the translational rate of viral, but not cellular, mRNAs. To characterize this effect, we looked for targets of NS1 influenza virus protein among cellular translation factors. We found that NS1 coimmunoprecipitates with eukaryotic initiation factor 4GI (eIF4GI), the large subunit of the cap-binding complex eIF4F, either in influenza virus-infected cells or in cells transfected with NS1 cDNA. Affinity chromatography studies using a purified His-NS1 protein-containing matrix showed that the fusion protein pulls down endogenous eIF4GI from COS-1 cells and labeled eIF4GI translated in vitro, but not the eIF4E subunit of the eIF4F factor. Similar in vitro binding experiments with eIF4GI deletion mutants indicated that the NS1-binding domain of eIF4GI is located between residues 157 and 550, in a region where no other component of the translational machinery is known to interact. Moreover, using overlay assays and pull-down experiments, we showed that NS1 and eIF4GI proteins interact directly, in an RNA-independent manner. Mapping of the eIF4GI-binding domain in the NS1 protein indicated that the first 113 N-terminal amino acids of the protein, but not the first 81, are sufficient to bind eIF4GI. The first of these mutants has been previously shown to act as a translational enhancer, while the second is defective in this activity. Collectively, these and previously published data suggest a model where NS1 recruits eIF4GI specifically to the 5' untranslated region (5' UTR) of the viral mRNA, allowing for the preferential translation of the influenza virus messengers.
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Affiliation(s)
- T Aragón
- Centro Nacional de Biotecnología (CSIC), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
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33
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Enami M, Enami K. Characterization of influenza virus NS1 protein by using a novel helper-virus-free reverse genetic system. J Virol 2000; 74:5556-61. [PMID: 10823862 PMCID: PMC112042 DOI: 10.1128/jvi.74.12.5556-5561.2000] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have developed a novel helper-virus-free reverse genetic system to genetically manipulate influenza A viruses. The RNPs, which were purified from the influenza A/WSN/33 (WSN) virus, were treated with RNase H in the presence of NS (nonstructural) cDNA fragments. This specifically digested the NS RNP. The NS-digested RNPs thus obtained were transfected into cells together with the in vitro-reconstituted NS RNP. The NS-digested RNPs alone did not rescue viruses; however, cotransfection with the NS RNP did. This protocol was also used to rescue the NP transfectant. We obtained two NS1 mutants, dl12 and N110, using this protocol. The dl12 NS gene contains a deletion of 12 amino acids at positions 66 to 77 near the N terminus. This virus was temperature sensitive in Madin-Darby bovine kidney (MDBK) cells as well as in Vero cells. The translation of all viral proteins as well as cellular proteins was significantly disrupted during a later time of infection at the nonpermissive temperature of 39 degrees C. The N110 mutant consists of 110 amino acids which are the N-terminal 48% of the WSN virus NS1 protein. Growth of this virus was significantly reduced at any temperature. In the virus-infected cells, translation of the M1 protein was reduced to 10 to 20% of that of the wild-type virus; however, the translation of neither the nucleoprotein nor NS1 was significantly interfered with, indicating the important role of NS1 in translational stimulation of the M1 protein.
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Affiliation(s)
- M Enami
- Department of Biochemistry, Kanazawa University School of Medicine, Takaramachi, Kanazawa, Ishikawa 920-8640, Japan.
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34
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Falcón AM, Fortes P, Marión RM, Beloso A, Ortín J. Interaction of influenza virus NS1 protein and the human homologue of Staufen in vivo and in vitro. Nucleic Acids Res 1999; 27:2241-7. [PMID: 10325410 PMCID: PMC148787 DOI: 10.1093/nar/27.11.2241] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A screening for human proteins capable of interacting with influenza virus NS1 has been carried out using the two-hybrid genetic trap in yeast. A cDNA corresponding to the human homologue of Drosophila melanogaster Staufen protein (hStaufen) was isolated that fulfilled all genetic controls of the two-hybrid protocol. Using a hStaufen cDNA isolated from a lambda human library, the interaction of hStaufen and NS1 proteins was characterised in vivo and in vitro. Co-transfection of NS1 cDNA and a partial cDNA of hStaufen led to the relocalisation of recombinant hStaufen protein from its normal accumulation site in the cytoplasm to the nuclear location of NS1 protein. NS1 and hStaufen proteins could be co-immunoprecipitated from extracts of co-transfected cells and from mixtures of extracts containing either protein, as well as from extracts of influenza virus-infected cells. Furthermore, both proteins co-localised in the ribosomal and polysomal fractions of influenza virus-infected cells. The interaction was also detected in pull-down experiments using a resin containing purified hStaufen and NS1 protein translated in vitro. Deletion mapping of the NS1 gene indicated that a mutant protein containing the N-terminal 81 amino acids is unable to interact with hStaufen, in spite of retaining full RNA-binding capacity. These results are discussed in relation to the possible mechanisms of action of hStaufen and its relevance for influenza virus infection.
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Affiliation(s)
- A M Falcón
- Centro Nacional de Biotecnología (CSIC), Campus de Cantoblanco, 28049 Madrid, Spain
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35
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Egorov A, Brandt S, Sereinig S, Romanova J, Ferko B, Katinger D, Grassauer A, Alexandrova G, Katinger H, Muster T. Transfectant influenza A viruses with long deletions in the NS1 protein grow efficiently in Vero cells. J Virol 1998; 72:6437-41. [PMID: 9658085 PMCID: PMC109801 DOI: 10.1128/jvi.72.8.6437-6441.1998] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
We established a reverse genetics system for the nonstructural (NS) gene segment of influenza A virus. This system is based on the use of the temperature-sensitive (ts) reassortant virus 25A-1. The 25A-1 virus contains the NS gene from influenza A/Leningrad/134/57 virus and the remaining gene segments from A/Puerto Rico (PR)/8/34 virus. This particular gene constellation was found to be responsible for the ts phenotype. For reverse genetics of the NS gene, a plasmid-derived NS gene from influenza A/PR/8/34 virus was ribonucleoprotein transfected into cells that were previously infected with the 25A-1 virus. Two subsequent passages of the transfection supernatant at 40 degreesC selected viruses containing the transfected NS gene derived from A/PR/8/34 virus. The high efficiency of the selection process permitted the rescue of transfectant viruses with large deletions of the C-terminal part of the NS1 protein. Viable transfectant viruses containing the N-terminal 124, 80, or 38 amino acids of the NS1 protein were obtained. Whereas all deletion mutants grew to high titers in Vero cells, growth on Madin-Darby canine kidney (MDCK) cells and replication in mice decreased with increasing length of the deletions. In Vero cells expression levels of viral proteins of the deletion mutants were similar to those of the wild type. In contrast, in MDCK cells the level of the M1 protein was significantly reduced for the deletion mutants.
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Affiliation(s)
- A Egorov
- Institute of Applied Microbiology, University of Agriculture, A-1190 Vienna, Austria.
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36
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Nemeroff ME, Barabino SM, Li Y, Keller W, Krug RM. Influenza virus NS1 protein interacts with the cellular 30 kDa subunit of CPSF and inhibits 3'end formation of cellular pre-mRNAs. Mol Cell 1998; 1:991-1000. [PMID: 9651582 DOI: 10.1016/s1097-2765(00)80099-4] [Citation(s) in RCA: 506] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Inhibition of the nuclear export of poly(A)-containing mRNAs caused by the influenza A virus NS1 protein requires its effector domain. Here, we demonstrate that the NS1 effector domain functionally interacts with the cellular 30 kDa subunit of CPSF, an essential component of the 3' end processing machinery of cellular pre-mRNAs. In influenza virus-infected cells, the NS1 protein is physically associated with CPSF 30 kDa. Binding of the NS1 protein to the 30 kDa protein in vitro prevents CPSF binding to the RNA substrate and inhibits 3' end cleavage and polyadenylation of host pre-mRNAs. The NS1 protein also inhibits 3' end processing in vivo, and the uncleaved pre-mRNA remains in the nucleus. Via this novel regulation of pre-mRNA 3' end processing, the NS1 protein selectively inhibits the nuclear export of cellular, and not viral, mRNAs.
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Affiliation(s)
- M E Nemeroff
- Department of Molecular Biology and Biochemistry Rutgers University Piscataway, New Jersey 08854, USA
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37
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Li Y, Yamakita Y, Krug RM. Regulation of a nuclear export signal by an adjacent inhibitory sequence: the effector domain of the influenza virus NS1 protein. Proc Natl Acad Sci U S A 1998; 95:4864-9. [PMID: 9560194 PMCID: PMC20179 DOI: 10.1073/pnas.95.9.4864] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/1998] [Accepted: 02/17/1998] [Indexed: 02/07/2023] Open
Abstract
In the cell nucleus the NS1 protein of influenza A virus inhibits both pre-mRNA splicing and the nuclear export of mRNAs. Both the RNA-binding and effector domains of the protein are required for these nuclear functions. Here we demonstrate that the NS1 protein has a latent nuclear export signal (NES) that is located at the amino end of the effector domain. In uninfected, transfected cells the NS1 protein is localized in the nucleus because the NES is specifically inhibited by the adjacent amino acid sequence in the effector domain. Substitution of alanine residues for specific amino acids in the adjacent sequence abrogates its inhibitory activity, thereby unmasking the NES and causing the full-length NS1 protein to be localized to the cytoplasm. In contrast to uninfected cells, a substantial amount of the NS1 protein in influenza virus-infected cells is located in the cytoplasm. Consequently, the NES of these NS1 protein molecules is unmasked in infected cells, indicating that the NS1 protein most likely carries out functions in the cytoplasm as well as the nucleus. A dramatically different localization of the NS1 protein occurs in cells that are infected by a virus encoding an NS1 protein lacking the NES: the shortened NS1 protein molecules are almost totally in the nucleus. Because the NES of the full-length NS1 protein is unmasked in infected but not uninfected cells, it is likely that this unmasking results from a specific interaction of another virus-specific protein with the NS1 protein.
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Affiliation(s)
- Y Li
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08855-1179, USA
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38
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Schlesinger RW, Husak PJ, Bradshaw GL, Panayotov PP. Mechanisms involved in natural and experimental neuropathogenicity of influenza viruses: evidence and speculation. Adv Virus Res 1998; 50:289-379. [PMID: 9521002 DOI: 10.1016/s0065-3527(08)60811-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- R W Schlesinger
- Department of Molecular Genetics and Microbiology, UMDNJ-Robert Wood Johnson Medical School, Piscataway 08854-5635, USA
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39
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Multiple Levels of Posttranscriptional Regulation of Influenza Virus Gene Expression. ACTA ACUST UNITED AC 1998. [DOI: 10.1006/smvy.1997.0136] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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40
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Marión RM, Aragón T, Beloso A, Nieto A, Ortín J. The N-terminal half of the influenza virus NS1 protein is sufficient for nuclear retention of mRNA and enhancement of viral mRNA translation. Nucleic Acids Res 1997; 25:4271-7. [PMID: 9336457 PMCID: PMC147036 DOI: 10.1093/nar/25.21.4271] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A collection of C-terminal deletion mutants of the influenza A virus NS1 gene has been used to define the regions of the NS1 protein involved in its functionality. Immunofluorescence analyses showed that the NS1 protein sequences downstream from position 81 are not required for nuclear transport. The capacity of these mutants to bind RNA was studied by in vitro binding tests using a model vRNA probe. These experiments showed that the N-terminal 81 amino acids of NS1 protein are sufficient for RNA binding activity. The collection of mutants also served to map the NS1 sequences required for nuclear retention of mRNA and for stimulation of viral mRNA translation, using the NP gene as reporter. The results obtained indicated that the N-terminal 113 amino acids of NS1 protein are sufficient for nuclear retention of mRNA and stimulation of viral mRNA translation. The possibility that this region of the protein may be sufficient for virus viability is discussed in relation to the sequences of NS1 genes of field isolates and to the phenotype of known viral mutants affected in the NS1 gene.
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Affiliation(s)
- R M Marión
- Centro Nacional de Biotecnología (CSIC), Cantoblanco, 28049 Madrid, Spain
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41
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Gale M, Katze MG. What happens inside lentivirus or influenza virus infected cells: insights into regulation of cellular and viral protein synthesis. Methods 1997; 11:383-401. [PMID: 9126553 DOI: 10.1006/meth.1996.0436] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Efficient manipulation of the regulatory mechanisms controlling host cell gene expression provides the means for productive infection by animal viruses. Upon infecting the host cell, viruses must: (i) bypass the cellular antiviral defense mechanisms to prevent the translational blocks imposed by the interferon pathway; and (ii) effectively "hijack" the host protein synthetic machinery into mass production of virion protein components. The multicomponent regulatory nature of cellular gene expression has provided the means of selecting for a diverse range of mechanisms utilized by animal viruses to ensure that replication efficiency is maintained throughout the virus life cycle. One important research component of the careful examination of gene regulation is those studies that focus on elucidating the mechanisms by which viruses control mRNA translation during host cell infection. Much of the work in our laboratory has focused on elucidating the strategies by which human immunodeficiency virus type 1 and influenza virus regulate protein synthesis during infection. Here we describe the ways in which these two distinctly different RNA viruses ensure the selective and efficient translation of their viral mRNAs in infected cells. These strategies include circumvention of the deleterious effects associated with activation of the interferon-induced protein kinase, PKR. Herein we describe our methodologies designed to elucidate the translational regulation in cells infected by these viruses. We conclude with a brief summary of new directions, utilizing these methods, taken toward understanding the translational control mechanisms imposed by these viral systems, and how our studies of virally infected cells have allowed us to identify growth-regulating components of normal, uninfected cells.
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Affiliation(s)
- M Gale
- Department of Microbiology, University of Washington School of Medicine, Seattle 98195, USA
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42
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Wolff T, O'Neill RE, Palese P. Interaction cloning of NS1-I, a human protein that binds to the nonstructural NS1 proteins of influenza A and B viruses. J Virol 1996; 70:5363-72. [PMID: 8764047 PMCID: PMC190494 DOI: 10.1128/jvi.70.8.5363-5372.1996] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The yeast interaction trap system was used to identify, NS1-I (for NS1 interactor), which is a human protein that binds to the nonstructural NS1 protein of the influenza A virus. NS1-I is a human homolog of the porcine 17beta-estradiol dehydrogenase precursor protein, to which it is 84% identical. We detected only one NS1-I mRNA species, of about 3.0 kb, in HeLa cells, and the NS1-I cDNA was found to have a coding capacity for a 79.6-kDa protein. However, immunoblot analysis detected predominantly a 55-kDa protein in human cells, suggesting that NS1-I, like the porcine 17beta-estradiol dehydrogenase, is posttranslationally processed. Using an in vitro coprecipitation assay, we showed that NS1-I interacts with NS1 proteins from extracts of cells infected with five different influenza A virus strains as well as with the NS1 of an influenza B virus. The fact that influenza A and influenza B virus NS1 proteins bind to NS1-I suggests that this cellular protein plays a role in the influenza virus life cycle.
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Affiliation(s)
- T Wolff
- Department of Microbiology, Mount Sinai School of Medicine, New York 10029, USA
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43
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Park YW, Katze MG. Translational control by influenza virus. Identification of cis-acting sequences and trans-acting factors which may regulate selective viral mRNA translation. J Biol Chem 1995; 270:28433-9. [PMID: 7499349 DOI: 10.1074/jbc.270.47.28433] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We have shown that sequences contained within the viral mRNA 5'-untranslated region (UTR) played a critical role in directing selective influenza viral mRNA translation. We therefore attempted to identify transacting factors that may regulate viral mRNA translation through interactions with the 5'-UTR and at the same time map the precise sequences to which these factors bind. We can now demonstrate that multiple cellular proteins interact with influenza viral but not cellular 5'-UTRs using gel mobility shift and UV cross-linking analyses. Gel supershift studies revealed that the La autoantigen was one of the cellular proteins that interacted with the viral 5'-UTR. Utilizing mutants of the viral mRNA 5' UTR, we have determined that sequences within the very 5'-conserved region and nucleotides immediately 3' are necessary but not always sufficient for binding certain cellular proteins. Northwestern analysis showed the binding of a distinct subset of cellular proteins to the viral 5'-UTR, but also demonstrated interactions of the viral nonstructural protein NS1. Gel shift analysis with purified recombinant NS1 confirmed the binding of the viral protein to a specific region of the viral 5'-UTRs. A model describing the possible role of these cellular and viral RNA-binding proteins in regulating influenza virus mRNA translation will be discussed.
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Affiliation(s)
- Y W Park
- Department of Microbiology, School of Medicine, University of Washington, Seattle 98195, USA
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44
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de la Luna S, Fortes P, Beloso A, Ortín J. Influenza virus NS1 protein enhances the rate of translation initiation of viral mRNAs. J Virol 1995; 69:2427-33. [PMID: 7884890 PMCID: PMC188917 DOI: 10.1128/jvi.69.4.2427-2433.1995] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The effect of NS1 protein on the efficiency of influenza virus mRNA translation was evaluated by determining the accumulation of nucleoprotein (NP) or M1 mRNAs in the cytoplasm of cells expressing either of these genes alone or in combination with the NS1 gene, as well as the total cell accumulation of NP or M1 protein. Coexpression of NS1, but not of NS2 protein, led to increases in the translation of these mRNAs in the range of 5- to 100-fold. This translation enhancement was specific for viral mRNAs, since the translation of neither cat nor lacZ mRNAs was affected by the coexpression of NS1 protein. The use of chimeric cat genes containing the 5'-extracistronic sequences of the influenza virus mRNAs corresponding to segment 2, 7, or 8 indicated that these sequences can in part account for the observed effect. The enhancement of viral mRNA translation mediated by NS1 protein was due to an increase in the translation initiation rate, since the sizes of NP-specific polysomes, but not those of lacZ-specific polysomes, was significantly higher in cells coexpressing NS1 protein than in those expressing only the NP gene.
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Affiliation(s)
- S de la Luna
- Centro Nacional de Biotecnología (Consejo Superior de Investigaciones Cientifícas), Universidad Autónoma de Madrid, Spain
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45
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Ward AC, Azad AA, Macreadie IG. Expression and characterisation of the influenza A virus non-structural protein NS1 in yeast. Arch Virol 1994; 138:299-314. [PMID: 7998836 DOI: 10.1007/bf01379133] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The influenza A virus non-structural protein NS1 was produced using a copper-inducible expression system in the yeast Saccharomyces cerevisiae. The protein produced had a molecular weight of 26 kDa by SDS-PAGE and was reactive with anti-NS1 antisera. The recombinant NS1 protein was targetted to the nucleolus/nuclear envelope fraction of the yeast cell nucleus, showing that its localisation signals remain functional in yeast. In addition, immune-electron microscopy detected cytoplasmic inclusions reminiscent of those seen in cells infected with some influenza strains. The NS1 protein was shown to be capable of in vivo self-interaction which probably forms the basis of its propensity to form inclusions. Expression of the protein was found to be toxic to yeast cells expressing it, supporting a role for the protein in the shutdown of influenza virus-infected cells. Deletion mapping of NS1 pointed to 2 regions of the molecule being important for this toxicity: a basic C-terminal stretch which has been shown to act as a nuclear localisation signal, and an N-terminal region implicated in RNA binding.
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Affiliation(s)
- A C Ward
- Biomolecular Research Institute, Parkville, Victoria, Australia
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46
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Qian XY, Alonso-Caplen F, Krug RM. Two functional domains of the influenza virus NS1 protein are required for regulation of nuclear export of mRNA. J Virol 1994; 68:2433-41. [PMID: 8139028 PMCID: PMC236721 DOI: 10.1128/jvi.68.4.2433-2441.1994] [Citation(s) in RCA: 124] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The influenza virus NS1 protein is the only known example of a protein that inhibits the nuclear export of mRNA. To identify the functional domains of this protein, we introduced 18 2- or 3-amino-acid substitutions at approximately equally spaced locations along the entire length of the protein. Two functional domains were identified. The domain near the amino end (amino acids 19 through 38) was shown to be the RNA-binding domain, by using a gel shift assay with purified NS1 protein and spliced viral NS2 mRNA as the RNA target. The second domain, which is in the carboxy half of the molecule, was presumed to be the effector domain that interacts with host nuclear proteins to carry out the nuclear RNA export function, by analogy with the effector domain of the Rev proteins of human immunodeficiency virus (HIV) and other lentiviruses which facilitate rather than inhibit nuclear RNA export. The NS1 protein has a 10-amino-acid sequence that is similar to the consensus sequence in the effector domains of lentivirus Rev proteins, specifically including two crucial leucines at positions 7 and 9 of this sequence. However, the effector domains of the NS1 and Rev (HIV type 1 [HIV-1]) proteins differed in several significant ways including the following: (i) unlike the HIV-1 Rev protein, NS1 effector domain mutants were negative recessive rather than negative dominant, (ii) the NS1 effector domain is about three times larger than the effector domain of the HIV-1 Rev protein, and (iii) unlike the HIV-1 protein, NS1 effector domain mutants exhibited a surprising property, a changed intracellular/intranuclear distribution, compared with the wild-type protein. These differences strongly suggest that the effector domains of the NS1 and Rev proteins interact with different nuclear protein targets, which likely explains the opposite effects of these two proteins on nuclear mRNA export.
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Affiliation(s)
- X Y Qian
- Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08855-1179
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47
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Enami K, Sato TA, Nakada S, Enami M. Influenza virus NS1 protein stimulates translation of the M1 protein. J Virol 1994; 68:1432-7. [PMID: 7508995 PMCID: PMC236597 DOI: 10.1128/jvi.68.3.1432-1437.1994] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The influenza virus NS1 protein was shown to stimulate translation of the M1 protein. M-CAT RNA, which contains the chloramphenicol acetyltransferase (CAT) reporter gene and the terminal noncoding sequence of segment 7 (coding for the M1 and M2 proteins), was ribonucleoprotein transfected into clone 76 cells expressing the influenza virus RNA polymerase and NP proteins required for the transcription and replication of influenza virus ribonucleoproteins. When the cells were superinfected with a recombinant vaccinia virus which expresses the NS1 protein, CAT expression from the M-CAT RNA was significantly stimulated but transcription was not altered. The expression of NS-CAT RNA, which contains noncoding sequences of segment 8 (coding for the NS1 and NS2 proteins), was not altered by the NS1 protein. Site-directed mutagenesis showed that the sequence GGUAGAUA upstream of the initiation codon on segment 7 was required for stimulation.
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Affiliation(s)
- K Enami
- Department of Biochemistry, Kanazawa University School of Medicine, Ishikawa, Japan
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Lucas WT, Whitaker-Dowling P, Kaifer CR, Youngner JS. Characterization of a unique protein produced by influenza A virus recovered from a long-term persistent infection. Virology 1988; 166:620-3. [PMID: 2972115 DOI: 10.1016/0042-6822(88)90538-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Virus isolated from a persistent infection initiated in BHK cells with influenza A/WSN/33 (H1N1) produced an unusual pattern of protein synthesis in productive infections of BHK cells: The levels of NP and M1 proteins were slightly reduced compared to an infection with wild-type WSN, while the other proteins (Pb1, Pb2, Pa, HA, NS1, and NS2) were synthesized at very low or undetectable levels. In addition, a new viral protein with an approximate molecular weight of 11 kDa (Pi protein) is made (Frielle et al., Virology 138, 103-117, 1984). When viral RNA was analyzed by the Northern blot technique, a deletion was found in the NS gene segment and in NS1 mRNA; all other RNAs were full-sized. Immunoprecipitation of in vitro translation products demonstrated that the Pi protein reacts specifically with anti-NS1 serum. In addition, the Pi protein, like the NS1 of the parental wild-type virus, accumulated in the nucleus of infected cells. These results indicate that the Pi protein is a mutated form of the NS1 protein encoded by a deleted NS segment and suggest that this mutation may be involved in the expression of the persistent virus phenotype.
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Affiliation(s)
- W T Lucas
- Department of Microbiology, Biochemistry and Molecular Biology, University of Pittsburgh, School of Medicine, Pennsylvania 15261
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Abstract
The NS1 protein of influenza A virus has been shown to enter and accumulate in the nuclei of virus-infected cells independently of any other influenza viral protein. Therefore, the NS1 protein contains within its polypeptide sequence the information that codes for its nuclear localization. To define the nuclear signal of the NS1 protein, a series of recombinant simian virus 40 vectors that express deletion mutants or fusion proteins was constructed. Analysis of the proteins expressed resulted in identification of two regions of the NS1 protein which affect its cellular location. Nuclear localization signal 1 (NLS1) contains the stretch of basic amino acids Asp-Arg-Leu-Arg-Arg (codons 34 to 38). This sequence is conserved in all NS1 proteins of influenza A viruses, as well as in that of influenza B viruses. NLS2 is defined within the region between amino acids 203 and 237. This domain is present in the NS1 proteins of most influenza A virus strains. NLS1 and NLS2 contain basic amino acids and are similar to previously defined nuclear signal sequences of other proteins.
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Abstract
It is an accepted concept that the pathogenicity of a virus is of polygenic nature. Because of their segmented genome, influenza viruses provide a suitable system to prove this concept. The studies employing virus mutants and reassortants have indicated that the pathogenicity depends on the functional integrity of each gene and on a gene constellation optimal for the infection of a given host. As a consequence, virtually every gene product of influenza virus has been reported to contribute to pathogenicity, but evidence is steadily growing that a key role has to be assigned to hemagglutinin. As the initiator of infection, hemagglutinin has a double function: (1) promotion of adsorption of the virus to the cell surface, and (2) penetration of the viral genome through a fusion process among viral and cellular membranes. Adsorption is based on the binding to neuraminic acid-containing receptors, and different virus strains display a distinct preference for specific oligosaccharides. Fusion capacity depends on proteolytic cleavage by host proteases, and variations in amino acid sequence at the cleavage site determine whether hemagglutinin is activated in a given cell. Differences in cleavability and presumably also in receptor specificity are important determinants for host tropism, spread of infection, and pathogenicity. The concept that proteolytic activation is a determinant for pathogenicity was originally derived from studies on avian influenza viruses, but there is now evidence that it may also be relevant for the disease in humans because bacterial proteases have been found to promote the development of influenza pneumonia in mammals.
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Affiliation(s)
- H D Klenk
- Institut für Virologie, Philipps-Universität Marburg, Federal Republic of Germany
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