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Kumari R, Sharma SD, Kumar A, Ende Z, Mishina M, Wang Y, Falls Z, Samudrala R, Pohl J, Knight PR, Sambhara S. Antiviral Approaches against Influenza Virus. Clin Microbiol Rev 2023; 36:e0004022. [PMID: 36645300 PMCID: PMC10035319 DOI: 10.1128/cmr.00040-22] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Preventing and controlling influenza virus infection remains a global public health challenge, as it causes seasonal epidemics to unexpected pandemics. These infections are responsible for high morbidity, mortality, and substantial economic impact. Vaccines are the prophylaxis mainstay in the fight against influenza. However, vaccination fails to confer complete protection due to inadequate vaccination coverages, vaccine shortages, and mismatches with circulating strains. Antivirals represent an important prophylactic and therapeutic measure to reduce influenza-associated morbidity and mortality, particularly in high-risk populations. Here, we review current FDA-approved influenza antivirals with their mechanisms of action, and different viral- and host-directed influenza antiviral approaches, including immunomodulatory interventions in clinical development. Furthermore, we also illustrate the potential utility of machine learning in developing next-generation antivirals against influenza.
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Affiliation(s)
- Rashmi Kumari
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Suresh D. Sharma
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Amrita Kumar
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Zachary Ende
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Oak Ridge Institute for Science and Education (ORISE), CDC Fellowship Program, Oak Ridge, Tennessee, USA
| | - Margarita Mishina
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Yuanyuan Wang
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Association of Public Health Laboratories, Silver Spring, Maryland, USA
| | - Zackary Falls
- Department of Biomedical Informatics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Ram Samudrala
- Department of Biomedical Informatics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Jan Pohl
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Paul R. Knight
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Suryaprakash Sambhara
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Sreenivasan CC, Sheng Z, Wang D, Li F. Host Range, Biology, and Species Specificity of Seven-Segmented Influenza Viruses-A Comparative Review on Influenza C and D. Pathogens 2021; 10:1583. [PMID: 34959538 PMCID: PMC8704295 DOI: 10.3390/pathogens10121583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/26/2021] [Accepted: 11/30/2021] [Indexed: 02/06/2023] Open
Abstract
Other than genome structure, influenza C (ICV), and D (IDV) viruses with seven-segmented genomes are biologically different from the eight-segmented influenza A (IAV), and B (IBV) viruses concerning the presence of hemagglutinin-esterase fusion protein, which combines the function of hemagglutinin and neuraminidase responsible for receptor-binding, fusion, and receptor-destroying enzymatic activities, respectively. Whereas ICV with humans as primary hosts emerged nearly 74 years ago, IDV, a distant relative of ICV, was isolated in 2011, with bovines as the primary host. Despite its initial emergence in swine, IDV has turned out to be a transboundary bovine pathogen and a broader host range, similar to influenza A viruses (IAV). The receptor specificities of ICV and IDV determine the host range and the species specificity. The recent findings of the presence of the IDV genome in the human respiratory sample, and high traffic human environments indicate its public health significance. Conversely, the presence of ICV in pigs and cattle also raises the possibility of gene segment interactions/virus reassortment between ICV and IDV where these viruses co-exist. This review is a holistic approach to discuss the ecology of seven-segmented influenza viruses by focusing on what is known so far on the host range, seroepidemiology, biology, receptor, phylodynamics, species specificity, and cross-species transmission of the ICV and IDV.
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Affiliation(s)
- Chithra C. Sreenivasan
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; (C.C.S.); (D.W.)
| | - Zizhang Sheng
- Aaron Diamond AIDS Research Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA;
| | - Dan Wang
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; (C.C.S.); (D.W.)
| | - Feng Li
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA; (C.C.S.); (D.W.)
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Sederdahl BK, Williams JV. Epidemiology and Clinical Characteristics of Influenza C Virus. Viruses 2020; 12:E89. [PMID: 31941041 PMCID: PMC7019359 DOI: 10.3390/v12010089] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 12/14/2022] Open
Abstract
Influenza C virus (ICV) is a common yet under-recognized cause of acute respiratory illness. ICV seropositivity has been found to be as high as 90% by 7-10 years of age, suggesting that most people are exposed to ICV at least once during childhood. Due to difficulty detecting ICV by cell culture, epidemiologic studies of ICV likely have underestimated the burden of ICV infection and disease. Recent development of highly sensitive RT-PCR has facilitated epidemiologic studies that provide further insights into the prevalence, seasonality, and course of ICV infection. In this review, we summarize the epidemiology and clinical characteristics of ICV.
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Affiliation(s)
- Bethany K. Sederdahl
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA;
| | - John V. Williams
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA;
- Institute for Infection, Inflammation, and Immunity in Children (i4Kids), University of Pittsburgh, Pittsburgh, PA 15224, USA
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Dawson WK, Lazniewski M, Plewczynski D. RNA structure interactions and ribonucleoprotein processes of the influenza A virus. Brief Funct Genomics 2019; 17:402-414. [PMID: 29040388 PMCID: PMC6252904 DOI: 10.1093/bfgp/elx028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In one more years, we will ‘celebrate’ an exact centenary of the Spanish flu pandemic. With the rapid evolution of the influenza virus, the possibility of novel pandemic remains ever a concern. This review covers our current knowledge of the influenza A virus: on the role of RNA in translation, replication, what is known of the expressed proteins and the protein products generated from alternative splicing, and on the role of base pairing in RNA structure. We highlight the main events associated with viral entry into the cell, the transcription and replication process, an export of the viral genetic material from the nucleus and the final release of the virus. We discuss the observed potential roles of RNA secondary structure (the RNA base-pairing arrangement) and RNA/RNA interactions in this scheme.
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Affiliation(s)
- Wayne K Dawson
- Bio-information Lab, University of Tokyo.,University of Warsaw, Center of New Technologies (CeNT), Warsaw, Poland
| | - Michal Lazniewski
- University of Warsaw, Center of New Technologies (CeNT), Warsaw, Poland
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Ramly RB, Olsen CM, Braaen S, Rimstad E. Infectious salmon anaemia virus nuclear export protein is encoded by a spliced gene product of genomic segment 7. Virus Res 2013; 177:1-10. [DOI: 10.1016/j.virusres.2013.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/01/2013] [Accepted: 07/02/2013] [Indexed: 11/16/2022]
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Speranskaya AS, Melnikova NV, Belenikin MS, Dmitriev AA, Oparina NY, Kudryavtseva AV. Genetic diversity and evolution of the influenza C virus. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412070149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Furukawa T, Muraki Y, Noda T, Takashita E, Sho R, Sugawara K, Matsuzaki Y, Shimotai Y, Hongo S. Role of the CM2 protein in the influenza C virus replication cycle. J Virol 2011; 85:1322-9. [PMID: 21106743 PMCID: PMC3020500 DOI: 10.1128/jvi.01367-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 11/10/2010] [Indexed: 02/07/2023] Open
Abstract
CM2 is the second membrane protein of influenza C virus. Although its biochemical characteristics, coding strategy, and properties as an ion channel have been extensively studied, the role(s) of CM2 in the virus replication cycle remains to be clarified. In order to elucidate this role, in the present study we generated CM2-deficient influenza C virus-like particles (VLPs) and examined the VLP-producing 293T cells, VLPs, and VLP-infected HMV-II cells. Quantification of viral RNA (vRNA) in the VLPs by real-time PCR revealed that the CM2-deficient VLPs contain approximately one-third of the vRNA found in wild-type VLPs although no significant differences were detected in the expression levels of viral components in VLP-producing cells or in the number and morphology of the generated VLPs. This finding suggests that CM2 is involved in the genome packaging process into VLPs. Furthermore, HMV-II cells infected with CM2-deficient VLPs exhibited significantly reduced reporter gene expression. Although CM2-deficient VLPs could be internalized into HMV-II cells as efficiently as wild-type VLPs, a smaller amount of vRNA was detected in the nuclear fraction of CM2-deficient VLP-infected cells than in that of wild-type VLP-infected cells, suggesting that the uncoating process of the CM2-deficient VLPs in the infected cells did not proceed in an appropriate manner. Taken together, the data obtained in the present study indicate that CM2 has a potential role in the genome packaging and uncoating processes of the virus replication cycle.
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Affiliation(s)
- Takatoshi Furukawa
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Yasushi Muraki
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Takeshi Noda
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Emi Takashita
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Ri Sho
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Kanetsu Sugawara
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Yoko Matsuzaki
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Yoshitaka Shimotai
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
| | - Seiji Hongo
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, Tokyo 108-8639, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan, Department of Public Health, Yamagata University Graduate School of Medical Science, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
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Muraki Y, Furukawa T, Kohno Y, Matsuzaki Y, Takashita E, Sugawara K, Hongo S. Influenza C virus NS1 protein upregulates the splicing of viral mRNAs. J Virol 2010; 84:1957-66. [PMID: 20007279 PMCID: PMC2812400 DOI: 10.1128/jvi.01627-09] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 11/25/2009] [Indexed: 11/20/2022] Open
Abstract
Pre-mRNAs of the influenza A virus M and NS genes are poorly spliced in virus-infected cells. By contrast, in influenza C virus-infected cells, the predominant transcript from the M gene is spliced mRNA. The present study was performed to investigate the mechanism by which influenza C virus M gene-specific mRNA (M mRNA) is readily spliced. The ratio of M1 encoded by a spliced M mRNA to CM2 encoded by an unspliced M mRNA in influenza C virus-infected cells was about 10 times larger than that in M gene-transfected cells, suggesting that a viral protein(s) other than M gene translational products facilitates viral mRNA splicing. RNase protection assays showed that the splicing of M mRNA in infected cells was much higher than that in M gene-transfected cells. The unspliced and spliced mRNAs of the influenza C virus NS gene encode two nonstructural (NS) proteins, NS1(C/NS1) and NS2(C/NS2), respectively. The introduction of premature translational termination into the NS gene, which blocked the synthesis of the C/NS1 and C/NS2 proteins, drastically reduced the splicing of NS mRNA, raising the possibility that C/NS1 or C/NS2 enhances viral mRNA splicing. The splicing of influenza C virus M mRNA was increased by coexpression of C/NS1, whereas it was reduced by coexpression of the influenza A virus NS1 protein (A/NS1). The splicing of influenza A virus M mRNA was also increased by coexpression of C/NS1, though it was inhibited by that of A/NS1. These results suggest that influenza C virus NS1, but not A/NS1, can upregulate viral mRNA splicing.
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Affiliation(s)
- Yasushi Muraki
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | - Takatoshi Furukawa
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | - Yoshihiko Kohno
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | - Yoko Matsuzaki
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | - Emi Takashita
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | - Kanetsu Sugawara
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
| | - Seiji Hongo
- Department of Infectious Diseases, Yamagata University Faculty of Medicine, Iida-Nishi, Yamagata 990-9585, Japan, Department of Microbiology, Kanazawa Medical University School of Medicine, Uchinada, Ishikawa 920-0293, Japan, Drug Analysis Department, Kashima Laboratory, Toxicological Science Division, Medi-Chem Business Segment, Mitsubishi Chemical Medience Corporation, Sunayama 14, Kamisu-City, Ibaraki, 314-0255, Japan, Influenza Virus Research Center, National Institute of Infectious Diseases, Gakuen 4-7-1, Musashimurayama, Tokyo 208-0011, Japan
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Robb NC, Smith M, Vreede FT, Fodor E. NS2/NEP protein regulates transcription and replication of the influenza virus RNA genome. J Gen Virol 2009; 90:1398-1407. [PMID: 19264657 DOI: 10.1099/vir.0.009639-0] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The influenza virus RNA polymerase transcribes the negative-sense viral RNA segments (vRNA) into mRNA and replicates them via complementary RNA (cRNA) intermediates into more copies of vRNA. It is not clear how the relative amounts of the three RNA products, mRNA, cRNA and vRNA, are regulated during the viral life cycle. We found that in viral ribonucleoprotein (vRNP) reconstitution assays involving only the minimal components required for viral transcription and replication (the RNA polymerase, the nucleoprotein and a vRNA template), the relative levels of accumulation of RNA products differed from those observed in infected cells, suggesting a regulatory role for additional viral proteins. Expression of the viral NS2/NEP protein in RNP reconstitution assays affected viral RNA levels by reducing the accumulation of transcription products and increasing the accumulation of replication products to more closely resemble those found during viral infection. This effect was functionally conserved in influenza A and B viruses and was influenza-virus-type-specific, demonstrating that the NS2/NEP protein changes RNA levels by specific alteration of the viral transcription and replication machinery, rather than through an indirect effect on the host cell. Although NS2/NEP has been shown previously to play a role in the nucleocytoplasmic export of viral RNPs, deletion of the nuclear export sequence region that is required for its transport function did not affect the ability of the protein to regulate RNA levels. A role for the NS2/NEP protein in the regulation of influenza virus transcription and replication that is independent of its viral RNP export function is proposed.
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Affiliation(s)
- Nicole C Robb
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Matt Smith
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Frank T Vreede
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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