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Chen G, Yang J, Wu Y, Wang H, Zhang X, Feng G. A CRM1-dependent nuclear export signal in Autographa californica multiple nucleopolyhedrovirus Ac93 is important for the formation of intranuclear microvesicles. J Virol 2024; 98:e0029924. [PMID: 38557225 PMCID: PMC11092359 DOI: 10.1128/jvi.00299-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 03/10/2024] [Indexed: 04/04/2024] Open
Abstract
Autographa californica multiple nucleopolyhedrovirus (AcMNPV) Ac93 is highly conserved in all sequenced baculovirus genomes, and it plays important roles in both the nuclear egress of nucleocapsids and the formation of intranuclear microvesicles. In this study, we characterized a cellular CRM1-dependent nuclear export signal (NES) of AcMNPV Ac93. Bioinformatic analysis revealed that AcMNPV Ac93 may contain an NES at amino acids 115-125. Green fluorescent protein (GFP) fused to the NES (GFP:NES) of AcMNPV Ac93 is localized to the cytoplasm of transfected cells. Multiple point mutation analysis demonstrated that NES is important for the nuclear export of GFP:NES. Bimolecular fluorescence complementation experiments and co-immunoprecipitation assays confirmed that Ac93 interacts with Spodoptera frugiperda CRM1 (SfCRM1). However, AcMNPV Ac34 inhibits cellular CRM1-dependent nuclear export of GFP:NES. To determine whether the NES in AcMNPV Ac93 is important for the formation of intranuclear microvesicles, an ac93-null AcMNPV bacmid was constructed; the wild-type and NES-mutated Ac93 were reinserted into the ac93-null AcMNPV bacmid. Immunofluorescence analysis showed that Ac93 and SfCRM1 were predominantly colocalized at intranuclear microvesicles in infected cells, while the construct containing point mutations at residues 123 and 125 of Ac93 resulted in a defect in budded virus production and the abolishment of intranuclear microvesicles. Together, these data demonstrate that Ac93 contains a functional NES, which is required for the production of progeny viruses and the formation of intranuclear microvesicles.IMPORTANCEAutographa californica multiple nucleopolyhedrovirus (AcMNPV) Ac93 is important for the formation of intranuclear microvesicles. However, how the baculovirus manipulates Ac93 for the formation of intranuclear microvesicles is unclear. In this study, we identified a nuclear export signal (NES) at amino acids 115-125 of AcMNPV Ac93. Our results showed that the NES is required for the interaction between Ac93 and Spodoptera frugiperda CRM1 (SfCRM1). However, AcMNPV Ac34 inhibits the nuclear export of green fluorescent protein fused to the NES. Our analysis revealed that Ac93 and SfCRM1 were predominantly colocalized at intranuclear microvesicles in AcMNPV-infected cells. Together, our results indicate that Ac93 participates in the formation of intranuclear microvesicles via the Ac93 NES-mediated CRM1 pathway.
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Affiliation(s)
- Guoqing Chen
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
| | - Jing Yang
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
| | - Yihong Wu
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
| | - Haoran Wang
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
| | - Xinxin Zhang
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
| | - Guozhong Feng
- State Key Laboratory of Rice Biology and Breeding, China National Rice Research Institute, Hangzhou, China
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2
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Dey S, Mondal A. Unveiling the role of host kinases at different steps of influenza A virus life cycle. J Virol 2024; 98:e0119223. [PMID: 38174932 PMCID: PMC10805039 DOI: 10.1128/jvi.01192-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024] Open
Abstract
Influenza viruses remain a major public health concern causing contagious respiratory illnesses that result in around 290,000-650,000 global deaths every year. Their ability to constantly evolve through antigenic shifts and drifts leads to the emergence of newer strains and resistance to existing drugs and vaccines. To combat this, there is a critical need for novel antiviral drugs through the introduction of host-targeted therapeutics. Influenza viruses encode only 14 gene products that get extensively modified through phosphorylation by a diverse array of host kinases. Reversible phosphorylation at serine, threonine, or tyrosine residues dynamically regulates the structure, function, and subcellular localization of viral proteins at different stages of their life cycle. In addition, kinases influence a plethora of signaling pathways that also regulate virus propagation by modulating the host cell environment thus establishing a critical virus-host relationship that is indispensable for executing successful infection. This dependence on host kinases opens up exciting possibilities for developing kinase inhibitors as next-generation anti-influenza therapy. To fully capitalize on this potential, extensive mapping of the influenza virus-host kinase interaction network is essential. The key focus of this review is to outline the molecular mechanisms by which host kinases regulate different steps of the influenza A virus life cycle, starting from attachment-entry to assembly-budding. By assessing the contributions of different host kinases and their specific phosphorylation events during the virus life cycle, we aim to develop a holistic overview of the virus-host kinase interaction network that may shed light on potential targets for novel antiviral interventions.
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Affiliation(s)
- Soumik Dey
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Arindam Mondal
- School of Bioscience, Indian Institute of Technology Kharagpur, Kharagpur, India
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3
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Dong M, Wang Y, Li P, Chen Z, Anirudhan V, Cui Q, Rong L, Du R. Allopregnanolone targets nucleoprotein as a novel influenza virus inhibitor. Virol Sin 2023; 38:931-939. [PMID: 37741571 PMCID: PMC10786660 DOI: 10.1016/j.virs.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Accepted: 09/19/2023] [Indexed: 09/25/2023] Open
Abstract
Influenza A virus (IAV) poses a global public health concern and remains an imminent threat to human health. Emerging antiviral resistance to the currently approved influenza drugs emphasizes the urgent need for new therapeutic entities against IAV. Allopregnanolone (ALLO) is a natural product that has been approved as an antidepressant drug. In the present study, we repurposed ALLO as a novel inhibitor against IAVs. Mechanistic studies demonstrated that ALLO inhibited virus replication by interfering with the nucleus translocation of viral nucleoprotein (NP). In addition, ALLO showed significant synergistic activity with compound 16, a hemagglutinin inhibitor of IAVs. In summary, we have identified ALLO as a novel influenza virus inhibitor targeting NP, providing a promising candidate that deserves further investigation as a useful anti-influenza strategy in the future.
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Affiliation(s)
- Meiyue Dong
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Yanyan Wang
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Ping Li
- College of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Zinuo Chen
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Varada Anirudhan
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, 60612, USA
| | - Qinghua Cui
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China; Qingdao Academy of Chinese Medical Sciences, Shandong University of Traditional Chinese Medicine, Qingdao, 266122, China.
| | - Lijun Rong
- Department of Microbiology and Immunology, College of Medicine, University of Illinois at Chicago, Chicago, 60612, USA.
| | - Ruikun Du
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China; Qingdao Academy of Chinese Medical Sciences, Shandong University of Traditional Chinese Medicine, Qingdao, 266122, China.
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4
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Chakraborty S, Chauhan A. Fighting the flu: a brief review on anti-influenza agents. Biotechnol Genet Eng Rev 2023:1-52. [PMID: 36946567 DOI: 10.1080/02648725.2023.2191081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
The influenza virus causes one of the most prevalent and lethal infectious viral diseases of the respiratory system; the disease progression varies from acute self-limiting mild fever to disease chronicity and death. Although both the preventive and treatment measures have been vital in protecting humans against seasonal epidemics or sporadic pandemics, there are several challenges to curb the influenza virus such as limited or poor cross-protection against circulating virus strains, moderate protection in immune-compromised patients, and rapid emergence of resistance. Currently, there are four US-FDA-approved anti-influenza drugs to treat flu infection, viz. Rapivab, Relenza, Tamiflu, and Xofluza. These drugs are classified based on their mode of action against the viral replication cycle with the first three being Neuraminidase inhibitors, and the fourth one targeting the viral polymerase. The emergence of the drug-resistant strains of influenza, however, underscores the need for continuous innovation towards development and discovery of new anti-influenza agents with enhanced antiviral effects, greater safety, and improved tolerability. Here in this review, we highlighted commercially available antiviral agents besides those that are at different stages of development including under clinical trials, with a brief account of their antiviral mechanisms.
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Affiliation(s)
| | - Ashwini Chauhan
- Department of Microbiology, Tripura University, Agartala, India
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5
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Zhang Y, Xu WF, Yu Y, Zhang Q, Huang L, Hao C, Shao CL, Wang W. Inhibition of influenza A virus replication by a marine derived quinolone alkaloid targeting virus nucleoprotein. J Med Virol 2023; 95:e28499. [PMID: 36653877 DOI: 10.1002/jmv.28499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/14/2022] [Accepted: 01/14/2023] [Indexed: 01/20/2023]
Abstract
Owing to the emergence of drug resistance and high morbidity and mortality, the need for novel anti-influenza A virus (IAV) drugs with divergent targets is highly sought after. Herein, a novel quinolone alkaloid (QLA) derived from marine fungus was discovered with broad-spectrum anti-IAV activities with low toxicity. Distinct from current anti-IAV drugs, QLA may block virus replication and viral RNA (vRNA) export from the nucleus by targeting virus nucleoprotein (NP). QLA can block the binding of chromosome region maintenance 1 to nuclear export signal 3 of NP to inhibit the nuclear export of NP and vRNP. QLA may also affect vRNP assembly by interfering with the binding of NP to RNA rather than NP oligomerization. Arg305 and Phe488-Gly490 may be required for the interaction between QLA and NP, and the binding pocket around these amino acids may be a promising target for anti-IAV drugs. Importantly, oral administration of QLA can protect the mice against IAV-induced death and weight loss, superior to the effects of the clinical drug oseltamivir. In summary, the marine derived compound QLA has the potential to be developed into a novel anti-IAV agent targeting virus NP protein in the future.
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Affiliation(s)
- Yang Zhang
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China
| | - Wei-Feng Xu
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China
| | - Yunjia Yu
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China
| | - Qun Zhang
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Lianghao Huang
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China
| | - Cui Hao
- Medical Research Center, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Chang-Lun Shao
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Wei Wang
- School of Medicine and Pharmacy, Key Laboratory of Marine Drugs, Ministry of Education, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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6
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Chauhan RP, Gordon ML. An overview of influenza A virus genes, protein functions, and replication cycle highlighting important updates. Virus Genes 2022; 58:255-269. [PMID: 35471490 DOI: 10.1007/s11262-022-01904-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
The recent research findings on influenza A virus (IAV) genome biology prompted us to present a comprehensive overview of IAV genes, protein functions, and replication cycle. The eight gene segments of the IAV genome encode 17 proteins, each having unique functions contributing to virus fitness in the host. The polymerase genes are essential determinants of IAV pathogenicity and virulence; however, other viral components also play crucial roles in the IAV replication, transmission, and adaptation. Specific adaptive mutations within polymerase (PB2, PB1, and PA) and glycoprotein-hemagglutinin (HA) and neuraminidase (NA) genes, may facilitate interspecies transmission and adaptation of IAV. The HA-NA interplay is essential for establishing the IAV infection; the low pH triggers the inactivation of HA-receptor binding, leading to significantly lower NA activities, indicating that the enzymatic function of NA is dependent on HA binding. While the HA and NA glycoproteins are required to initiate infection, M1, M2, NS1, and NEP proteins are essential for cytoplasmic trafficking of viral ribonucleoproteins (vRNPs) and the assembly of the IAV virions. The mechanisms that enable IAV to exploit the host cell resources to advance the infection are discussed. A comprehensive understanding of IAV genome biology is essential for developing antivirals to combat the IAV disease burden.
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Affiliation(s)
- Ravendra P Chauhan
- School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, 719 Umbilo Road, Durban, 4001, South Africa
| | - Michelle L Gordon
- School of Laboratory Medicine and Medical Sciences, Nelson R. Mandela School of Medicine, College of Health Sciences, University of KwaZulu-Natal, 719 Umbilo Road, Durban, 4001, South Africa.
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7
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Trothen SM, Zang RX, Lurie A, Dikeakos JD. PACS-1 contains distinct motifs for nuclear-cytoplasmic transport and interacts with the RNA-binding protein PTBP1 in the nucleus and cytosol. FEBS Lett 2021; 596:232-248. [PMID: 34822171 DOI: 10.1002/1873-3468.14243] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/10/2022]
Abstract
Phosphofurin acidic cluster sorting protein 1 (PACS-1) is canonically a cytosolic trafficking protein, yet recent reports have described nuclear roles for PACS-1. Herein, we sought to define the nuclear transport mechanism of PACS-1. We demonstrate that PACS-1 nucleocytoplasmic trafficking is dependent on its interaction with the nuclear transport receptors importin alpha 5 and exportin 1. PACS-1 nuclear entry and exit are defined by a nuclear localization signal (NLS, residues 311-318) and nuclear export signal (NES3, residues 366-375). Mutation of the PACS-1 NLS and NES3 altered the localization of a complex formed between PACS-1 and an RNA-binding protein, polypyrimidine tract-binding protein 1. Overall, we identify the nuclear localization mechanism of PACS-1 and highlight a potential role for PACS-1 in RNA-binding protein trafficking.
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Affiliation(s)
- Steven M Trothen
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Rong Xuan Zang
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Antony Lurie
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Jimmy D Dikeakos
- Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
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8
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Acetylation, Methylation and Allysine Modification Profile of Viral and Host Proteins during Influenza A Virus Infection. Viruses 2021; 13:v13071415. [PMID: 34372620 PMCID: PMC8310381 DOI: 10.3390/v13071415] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/08/2021] [Accepted: 07/18/2021] [Indexed: 12/18/2022] Open
Abstract
Protein modifications dynamically occur and regulate biological processes in all organisms. Towards understanding the significance of protein modifications in influenza virus infection, we performed a global mass spectrometry screen followed by bioinformatics analyses of acetylation, methylation and allysine modification in human lung epithelial cells in response to influenza A virus infection. We discovered 8 out of 10 major viral proteins and 245 out of 2280 host proteins detected to be differentially modified by three modifications in infected cells. Some of the identified proteins were modified on multiple amino acids residues and by more than one modification; the latter occurred either on different or same residues. Most of the modified residues in viral proteins were conserved across >40 subtypes of influenza A virus, and influenza B or C viruses and located on the protein surface. Importantly, many of those residues have already been determined to be critical for the influenza A virus. Similarly, many modified residues in host proteins were conserved across influenza A virus hosts like humans, birds, and pigs. Finally, host proteins undergoing the three modifications clustered in common functional networks of metabolic, cytoskeletal, and RNA processes, all of which are known to be exploited by the influenza A virus.
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9
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Yang F, Pang B, Lai KK, Cheung NN, Dai J, Zhang W, Zhang J, Chan KH, Chen H, Sze KH, Zhang H, Hao Q, Yang D, Yuen KY, Kao RY. Discovery of a Novel Specific Inhibitor Targeting Influenza A Virus Nucleoprotein with Pleiotropic Inhibitory Effects on Various Steps of the Viral Life Cycle. J Virol 2021; 95:e01432-20. [PMID: 33627391 PMCID: PMC8104107 DOI: 10.1128/jvi.01432-20] [Citation(s) in RCA: 9] [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: 08/30/2020] [Accepted: 01/29/2021] [Indexed: 11/23/2022] Open
Abstract
Influenza A viruses (IAVs) continue to pose an imminent threat to humans due to annual influenza epidemic outbreaks and episodic pandemics with high mortality rates. In this context, the suboptimal vaccine coverage and efficacy, coupled with recurrent events of viral resistance against a very limited antiviral portfolio, emphasize an urgent need for new additional prophylactic and therapeutic options, including new antiviral targets and drugs with new mechanisms of action to prevent and treat influenza virus infection. Here, we characterized a novel influenza A virus nucleoprotein (NP) inhibitor, FA-6005, that inhibited a broad spectrum of human pandemic and seasonal influenza A and B viruses in vitro and protects mice against lethal influenza A virus challenge. The small molecule FA-6005 targeted a conserved NP I41 domain and acted as a potentially broad, multimechanistic anti-influenza virus therapeutic since FA-6005 suppressed influenza virus replication and perturbed intracellular trafficking of viral ribonucleoproteins (vRNPs) from early to late stages. Cocrystal structures of the NP/FA-6005 complex reconciled well with concurrent mutational studies. This study provides the first line of direct evidence suggesting that the newly identified NP I41 pocket is an attractive target for drug development that inhibits multiple functions of NP. Our results also highlight FA-6005 as a promising candidate for further development as an antiviral drug for the treatment of IAV infection and provide chemical-level details for inhibitor optimization.IMPORTANCE Current influenza antivirals have limitations with regard to their effectiveness and the potential emergence of resistance. Therefore, there is an urgent need for broad-spectrum inhibitors to address the considerable challenges posed by the rapid evolution of influenza viruses that limit the effectiveness of vaccines and lead to the emergence of antiviral drug resistance. Here, we identified a novel influenza A virus NP antagonist, FA-6005, with broad-spectrum efficacy against influenza viruses, and our study presents a comprehensive study of the mode of action of FA-6005 with the crystal structure of the compound in complex with NP. The influenza virus inhibitor holds promise as an urgently sought-after therapeutic option offering a mechanism of action complementary to existing antiviral drugs for the treatment of influenza virus infection and should further aid in the development of universal therapeutics.
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Affiliation(s)
- Fang Yang
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Bo Pang
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Kin Kui Lai
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Nam Nam Cheung
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Jun Dai
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Weizhe Zhang
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Jinxia Zhang
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Kwok-Hung Chan
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Honglin Chen
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
| | - Kong-Hung Sze
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
| | - Hongmin Zhang
- Department of Biology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, Southern University of Science and Technology, Shenzhen, China
- Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, China
- SUSTech-HKU Joint Laboratories for Matrix Biology and Diseases, Southern University of Science and Technology, Shenzhen, China
| | - Quan Hao
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Dan Yang
- Department of Chemistry, The University of Hong Kong, Hong Kong, China
| | - Kwok-Yung Yuen
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
| | - Richard Y Kao
- Department of Microbiology, The University of Hong Kong, Hong Kong, China
- Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong, China
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong, China
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10
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Gales JP, Kubina J, Geldreich A, Dimitrova M. Strength in Diversity: Nuclear Export of Viral RNAs. Viruses 2020; 12:E1014. [PMID: 32932882 PMCID: PMC7551171 DOI: 10.3390/v12091014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 12/11/2022] Open
Abstract
The nuclear export of cellular mRNAs is a complex process that requires the orchestrated participation of many proteins that are recruited during the early steps of mRNA synthesis and processing. This strategy allows the cell to guarantee the conformity of the messengers accessing the cytoplasm and the translation machinery. Most transcripts are exported by the exportin dimer Nuclear RNA export factor 1 (NXF1)-NTF2-related export protein 1 (NXT1) and the transcription-export complex 1 (TREX1). Some mRNAs that do not possess all the common messenger characteristics use either variants of the NXF1-NXT1 pathway or CRM1, a different exportin. Viruses whose mRNAs are synthesized in the nucleus (retroviruses, the vast majority of DNA viruses, and influenza viruses) exploit both these cellular export pathways. Viral mRNAs hijack the cellular export machinery via complex secondary structures recognized by cellular export factors and/or viral adapter proteins. This way, the viral transcripts succeed in escaping the host surveillance system and are efficiently exported for translation, allowing the infectious cycle to proceed. This review gives an overview of the cellular mRNA nuclear export mechanisms and presents detailed insights into the most important strategies that viruses use to export the different forms of their RNAs from the nucleus to the cytoplasm.
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Affiliation(s)
- Jón Pol Gales
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
| | - Julie Kubina
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
- SVQV UMR-A 1131, INRAE, Université de Strasbourg, F-68000 Colmar, France
| | - Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
| | - Maria Dimitrova
- Institut de Biologie Moléculaire des Plantes, The French National Center for Scientific Research (CNRS) UPR2357, Université de Strasbourg, F-67084 Strasbourg, France; (J.P.G.); (J.K.); (A.G.)
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11
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A human cell polarity protein Lgl2 regulates influenza A virus nucleoprotein exportation from nucleus in MDCK cells. J Biosci 2020. [DOI: 10.1007/s12038-020-00039-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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12
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Makau JN, Watanabe K, Otaki H, Mizuta S, Ishikawa T, Kamatari YO, Nishida N. A Quinolinone Compound Inhibiting the Oligomerization of Nucleoprotein of Influenza A Virus Prevents the Selection of Escape Mutants. Viruses 2020; 12:v12030337. [PMID: 32204549 PMCID: PMC7150793 DOI: 10.3390/v12030337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/10/2020] [Accepted: 03/18/2020] [Indexed: 02/07/2023] Open
Abstract
The emergence of resistance to currently available anti-influenza drugs has heightened the need for antivirals with novel mechanisms of action. The influenza A virus (IAV) nucleoprotein (NP) is highly conserved and essential for the formation of viral ribonucleoprotein (vRNP), which serves as the template for replication and transcription. Recently, using in silico screening, we identified an antiviral compound designated NUD-1 (a 4-hydroxyquinolinone derivative) as a potential inhibitor of NP. In this study, we further analyzed the interaction between NUD-1 and NP and found that the compound interferes with the oligomerization of NP, which is required for vRNP formation, leading to the suppression of viral transcription, protein synthesis, and nuclear export of NP. We further assessed the selection of resistant variants by serially passaging a clinical isolate of the 2009 H1N1 pandemic influenza virus in the presence of NUD-1 or oseltamivir. NUD-1 did not select for resistant variants after nine passages, whereas oseltamivir selected for resistant variants after five passages. Our data demonstrate that NUD-1 interferes with the oligomerization of NP and less likely induces drug-resistant variants than oseltamivir; hence, it is a potential lead compound for the development of novel anti-influenza drugs.
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Affiliation(s)
- Juliann Nzembi Makau
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (J.N.M.); (N.N.)
| | - Ken Watanabe
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (J.N.M.); (N.N.)
- Department of Lifestyle Design, Faculty of Human Ecology, Yasuda Women’s University, 6-13-1 Yasuhigashi, Asaminami ward, Hiroshima 731-0153, Japan
- Correspondence: ; Tel.: +81-82-878-9139
| | - Hiroki Otaki
- Center for Bioinformatics and Molecular Medicine, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (H.O.); (S.M.)
| | - Satoshi Mizuta
- Center for Bioinformatics and Molecular Medicine, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (H.O.); (S.M.)
| | - Takeshi Ishikawa
- Department of Chemistry, Biotechnology, and Chemical Engineering, Graduate School of Science and Engineering, Kagoshima University, 1-21-40 Korimoto, Kagoshima 890-0065, Japan;
| | - Yuji O. Kamatari
- Life Science Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan;
| | - Noriyuki Nishida
- Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; (J.N.M.); (N.N.)
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13
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Heterogeneous Nuclear Ribonucleoprotein A1 and Lamin A/C Modulate Nucleocytoplasmic Shuttling of Avian Reovirus p17. J Virol 2019; 93:JVI.00851-19. [PMID: 31375578 DOI: 10.1128/jvi.00851-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/17/2019] [Indexed: 01/15/2023] Open
Abstract
Avian reovirus (ARV) p17 protein continuously shuttles between the nucleus and the cytoplasm via transcription-dependent and chromosome region maintenance 1 (CRM1)-independent mechanisms. Nevertheless, whether cellular proteins modulate nucleocytoplasmic shuttling of p17 remains unknown. This is the first report that heterogeneous nuclear ribonucleoprotein (hnRNP) A1 serves as a carrier protein to modulate nucleocytoplasmic shuttling of p17. Both in vitro and in vivo studies indicated that direct interaction of p17 with hnRNP A1 maps within the amino terminus (amino acids [aa] 19 to 40) of p17 and the Gly-rich region of the C terminus of hnRNP A1. Furthermore, our results reveal that the formation of p17-hnRNP A1-transportin 1 carrier-cargo complex is required to modulate p17 nuclear import. Utilizing sequence and mutagenesis analyses, we have identified nuclear export signal (NES) 19LSLRELAI26 of p17. Mutations of these residues causes a nuclear retention of p17. In this work, we uncovered that the N-terminal 21 amino acids (aa 19 to 40) of p17 that comprise the NES can modulate both p17 and hnRNP A1 interaction and nucleocytoplasmic shuttling of p17. In this work, the interaction site of p17 with lamin A/C was mapped within the amino terminus (aa 41 to 60) of p17 and p17 colocalized with lamin A/C at the nuclear envelope. Knockdown of hnRNP A1 or lamin A/C led to inhibition of nucleocytoplasmic shuttling of p17 and reduced virus yield. Collectively, the results of this study provide mechanistic insights into hnRNP A1 and lamin A/C-modulated nucleocytoplasmic shuttling of the ARV p17 protein.IMPORTANCE Avian reoviruses (ARVs) cause considerable economic losses in the poultry industry. The ARV p17 protein continuously shuttles between the nucleus and the cytoplasm to regulate several cellular signaling pathways and interacts with several cellular proteins to cause translation shutoff, cell cycle arrest, and autophagosome formation, all of which enhance virus replication. To date the mechanisms underlying nucleocytoplasmic shuttling of p17 remain largely unknown. Here we report that hnRNP A1 and lamin A/C serve as carrier and mediator proteins to modulate nucleocytoplasmic shuttling of p17. The formation of p17-hnRNP A1-transportin 1 carrier-cargo complex is required to modulate p17 nuclear import. Furthermore, we have identified an NES-containing nucleocytoplasmic shuttling domain (aa 19 to 40) of p17 that is critical for binding to hnRNP A1 and for nucleocytoplasmic shuttling of p17. This study provides novel insights into how hnRNP A1 and lamin A/C modulate nucleocytoplasmic shuttling of the ARV p17 protein.
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14
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Cui L, Zheng W, Li M, Bai X, Yang W, Li J, Fan W, Gao GF, Sun L, Liu W. Phosphorylation Status of Tyrosine 78 Residue Regulates the Nuclear Export and Ubiquitination of Influenza A Virus Nucleoprotein. Front Microbiol 2019; 10:1816. [PMID: 31440228 PMCID: PMC6692485 DOI: 10.3389/fmicb.2019.01816] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 07/23/2019] [Indexed: 12/31/2022] Open
Abstract
Phosphorylation and dephosphorylation of nucleoprotein (NP) play significant roles in the life cycle of influenza A virus (IAV), and the biological functions of each phosphorylation site on NP are not exactly the same in controlling viral replication. Here, we identified tyrosine 78 residue (Y78) of NP as a novel phosphorylation site by mass spectrometry. Y78 is highly conserved, and the constant NP phosphorylation mimicked by Y78E delayed NP nuclear export through reducing the binding of NP to the cellular export receptor CRM1, and impaired virus growth. Furthermore, the tyrosine kinase inhibitors Dasatinib and AG490 reduced Y78 phosphorylation and accelerated NP nuclear export, suggesting that the Janus and Src kinases-catalyzed Y78 phosphorylation regulated NP nuclear export during viral replication. More importantly, we found that the NP phosphorylation could suppress NP ubiquitination via weakening the interaction between NP and E3 ubiquitin ligase TRIM22, which demonstrated a cross-talk between the phosphorylation and ubiquitination of NP. This study suggests that the phosphorylation status of Y78 regulates IAV replication by inhibiting the nuclear export and ubiquitination of NP. Overall, these findings shed new light on the biological roles of NP phosphorylation, especially its negative role in NP ubiquitination.
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Affiliation(s)
- Liang Cui
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Weinan Zheng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Minghui Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoyuan Bai
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Wenxian Yang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Wenhui Fan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - George Fu Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.,Chinese National Influenza Center (CNIC), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing, China
| | - Lei Sun
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Wenjun Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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15
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Zhu L, Zhao W, Lu J, Li S, Zhou K, Jiang W, Duan X, Fu L, Yu B, Cai KQ, Gao GF, Liu W, Fang M. Influenza virus matrix protein M1 interacts with SLD5 to block host cell cycle. Cell Microbiol 2019; 21:e13038. [PMID: 31050118 DOI: 10.1111/cmi.13038] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/16/2019] [Accepted: 04/29/2019] [Indexed: 01/09/2023]
Abstract
Influenza virus matrix 1 protein (M1) is highly conserved and plays essential roles at many stages of virus life cycle. Here, we used a yeast two-hybrid system to identify the host protein SLD5, a component of the GINS complex, which is essential for the initiation of DNA replication in eukaryotic cells, as a new M1 interacting protein. M1 from several different influenza virus strains all interacted with SLD5. Overexpression of SLD5 suppressed influenza virus replication. Transient, stable, or inducible expression of M1 induced host cell cycle blockade at G0/G1 phase. Moreover, SLD5 partially rescued M1 expression- or influenza virus infection-induced G0/G1 phase accumulation in cell lines and primary mouse embryonic fibroblasts. Importantly, SLD5 transgenic mice exhibited higher resistance and improved lung epithelial regeneration after virus infection compared with wild-type mice. Therefore, influenza virus M1 blocks host cell cycle process by interacting with SLD5. Our finding reveals the multifunctional nature of M1 and provides new insight for understanding influenza virus-host interaction.
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Affiliation(s)
- Li Zhu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Wenming Zhao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jiao Lu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Shan Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Kai Zhou
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Jiang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Xuefeng Duan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Lifeng Fu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Bolan Yu
- Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Kathy Q Cai
- Department of Pathology, Fox Chase Cancer Center, Philadelphia, Pennsylvania, USA
| | - George Fu Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wenjun Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Min Fang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.,International College, University of Chinese Academy of Sciences, Beijing, China
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16
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Zheng W, Fan W, Zhang S, Jiao P, Shang Y, Cui L, Mahesutihan M, Li J, Wang D, Gao GF, Sun L, Liu W. Naproxen Exhibits Broad Anti-influenza Virus Activity in Mice by Impeding Viral Nucleoprotein Nuclear Export. Cell Rep 2019; 27:1875-1885.e5. [PMID: 31067470 DOI: 10.1016/j.celrep.2019.04.053] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/01/2019] [Accepted: 04/11/2019] [Indexed: 12/16/2022] Open
Abstract
Naproxen is a non-steroidal anti-inflammatory drug that has previously been shown to exert antiviral activity against influenza A virus by inhibiting nucleoprotein (NP) binding to RNA. Here, we show that naproxen is a potential broad, multi-mechanistic anti-influenza virus therapeutic, as it inhibits influenza B virus replication both in vivo and in vitro. The anti-influenza B virus activity of naproxen is more efficient than that of the commonly used neuraminidase inhibitor oseltamivir in mice. Furthermore, the NP of influenza B virus (BNP) has a higher binding affinity to naproxen than influenza A virus NP (ANP). Specifically, naproxen targets the NP at residues F209 (BNP) and Y148 (ANP). This interaction antagonizes the nuclear export of NP normally mediated by the host export protein CRM1. This study reveals a crucial mechanism of broad-spectrum anti-influenza virus activity of naproxen, suggesting that the existing drug naproxen may be used as an anti-influenza drug.
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Affiliation(s)
- Weinan Zheng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wenhui Fan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuang Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Pengtao Jiao
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresourses & Laboratory of Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine, Guangxi University, Nanning 530004, China
| | - Yingli Shang
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Veterinary Medicine, Shandong Agricultural University, Tai'an 271018, China
| | - Liang Cui
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Madina Mahesutihan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Dayan Wang
- Chinese National Influenza Center (CNIC), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing 102206, China
| | - George Fu Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China; Chinese National Influenza Center (CNIC), National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention (China CDC), Beijing 102206, China
| | - Lei Sun
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Wenjun Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China
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17
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Švančarová P, Betáková T. Conserved methionine 165 of matrix protein contributes to the nuclear import and is essential for influenza A virus replication. Virol J 2018; 15:187. [PMID: 30509291 PMCID: PMC6276163 DOI: 10.1186/s12985-018-1056-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/13/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND The influenza matrix protein (M1) layer under the viral membrane plays multiple roles in virus assembly and infection. N-domain and C-domain are connected by a loop region, which consists of conserved RQMV motif. METHODS The function of the highly conserve RQMV motif in the influenza virus life cycle was investigated by site-directed mutagenesis and by rescuing mutant viruses by reverse genetics. Co-localization of M1 with nucleoprotein (NP), clustered mitochondria homolog protein (CLUH), chromosome region maintenance 1 protein (CRM1), or plasma membrane were studied by confocal microscopy. RESULTS Mutant viruses containing an alanine substitution of R163, Q164 and V166 result in the production of the virus indistinguishable from the wild type phenotype. Single M165A substitution was lethal for rescuing infection virus and had a striking effect on the distribution of M1 and NP proteins. We have observed statistically significant reduction in distribution of both M165A (p‹0,05) and NP (p‹0,001) proteins to the nucleus in the cells transfected with the reverse -genetic system with mutated M1. M165A protein was co-localized with CLUH protein in the cytoplasm and around the nucleus but transport of M165-CLUH complex through the nuclear membrane was restricted. CONCLUSIONS Our finding suggest that methionine 165 is essential for virus replication and RQMV motif is involved in the nuclear import of viral proteins.
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Affiliation(s)
- Petra Švančarová
- Biomedical Research Center - Slovaks Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic
| | - Tatiana Betáková
- Biomedical Research Center - Slovaks Academy of Sciences, Institute of Virology, Bratislava, Slovak Republic.
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18
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CDC25B promotes influenza A virus replication by regulating the phosphorylation of nucleoprotein. Virology 2018; 525:40-47. [PMID: 30240957 DOI: 10.1016/j.virol.2018.09.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/06/2018] [Accepted: 09/06/2018] [Indexed: 12/24/2022]
Abstract
Cell division cycle 25 B (CDC25B) is a member of the CDC25 phosphatase family. It can dephosphorylate cyclin-dependent kinases and regulate the cell division cycle. Moreover, siRNA knockdown of CDC25B impairs influenza A virus (IAV) replication. Here, to further understand the regulatory mechanism of CDC25B for IAV replication, a CDC25B-knockout (KO) 293T cell line was constructed using CRISPR/Cas9. The present data indicated that the replication of IAV was decreased in CDC25B-KO cells. Additionally, CDC25B deficiency damaged viral polymerase activity, nucleoprotein (NP) self-oligomerization, and NP nuclear export. Most importantly, we found that the NP phosphorylation levels were significantly increased in CDC25B-KO cells. These findings indicate that CDC25B facilitates the dephosphorylation of NP, which is vital for regulating NP functions and the life cycle of IAV.
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19
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Li Y, Sun L, Zheng W, Madina Mahesutihan, Li J, Bi Y, Wang H, Liu W, Luo TR. Phosphorylation and dephosphorylation of threonine 188 in nucleoprotein is crucial for the replication of influenza A virus. Virology 2018; 520:30-38. [PMID: 29775781 DOI: 10.1016/j.virol.2018.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 10/16/2022]
Abstract
Nucleoprotein (NP) is a major component of the viral ribonucleoprotein (vRNP) complex that is responsible for viral replication, transcription and packaging of influenza A virus. Phosphorylation of NP plays an important role during viral infection. In the present study, we identified threonine 188 (T188) as a novel phosphorylated residue in the NP of influenza A virus by using mass spectrometry. T188 is located within nuclear export signal 2 (NES2) which is chromosome region maintenance 1 (CRM1)-independent. We observed that the phosphorylation and dephosphorylation of residue T188 regulated viral replication by controlling NES2-dependent NP nuclear export and the polymerase activity of the vRNP complex. Our findings provide further insights for understanding the replication of influenza A virus.
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Affiliation(s)
- Yun Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresourses & Laboratory of Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine, Guangxi University, Nanning 530004, Guangxi, China; CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lei Sun
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Weinan Zheng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Madina Mahesutihan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuhai Bi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Heran Wang
- International Department, Beijing National Day School, Beijing 100039, China
| | - Wenjun Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresourses & Laboratory of Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine, Guangxi University, Nanning 530004, Guangxi, China; CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Ting Rong Luo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresourses & Laboratory of Animal Infectious Diseases, College of Animal Sciences and Veterinary Medicine, Guangxi University, Nanning 530004, Guangxi, China.
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20
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CASCIRE surveillance network and work on avian influenza viruses. SCIENCE CHINA-LIFE SCIENCES 2017; 60:1386-1391. [PMID: 29294220 DOI: 10.1007/s11427-017-9251-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/23/2017] [Indexed: 12/12/2022]
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21
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Huang F, Chen J, Zhang J, Tan L, Lu G, Luo Y, Pan T, Liang J, Li Q, Luo B, Zhang H, Lu G. Identification of a novel compound targeting the nuclear export of influenza A virus nucleoprotein. J Cell Mol Med 2017; 22:1826-1839. [PMID: 29193684 PMCID: PMC5824420 DOI: 10.1111/jcmm.13467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/23/2017] [Indexed: 12/25/2022] Open
Abstract
Although antiviral drugs are available for the treatment of influenza infection, it is an urgent requirement to develop new antiviral drugs regarding the emergence of drug‐resistant viruses. The nucleoprotein (NP) is conserved among all influenza A viruses (IAVs) and has no cellular equivalent. Therefore, NP is an ideal target for the development of new IAV inhibitors. In this study, we identified a novel anti‐influenza compound, ZBMD‐1, from a library of 20,000 compounds using cell‐based influenza A infection assays. We found that ZBMD‐1 inhibited the replication of H1N1 and H3N2 influenza A virus strains in vitro, with an IC50 ranging from 0.41–1.14 μM. Furthermore, ZBMD‐1 inhibited the polymerase activity and specifically impaired the nuclear export of NP. Further investigation indicated that ZBMD‐1 binds to the nuclear export signal 3 (NES3) domain and the dimer interface of the NP pocket. ZBMD‐1 also protected mice that were challenged with lethal doses of A/PR/8/1934 (H1N1) virus, effectively relieving lung histopathology changes, as well as strongly inhibiting the expression of pro‐inflammatory cytokines/chemokines, without inducing toxicity effects in mice. These results suggest that ZBMD‐1 is a promising anti‐influenza compound which can be further investigated as a useful strategy against IAVs in the future.
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Affiliation(s)
- Feng Huang
- Department of Respiration, Affiliated Guangzhou Women and Children's Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.,Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Jingliang Chen
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Junsong Zhang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Likai Tan
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Gui Lu
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yongjie Luo
- Institute of Medicinal Chemistry, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ting Pan
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Juanran Liang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Qianwen Li
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Baohong Luo
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Hui Zhang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Guangdong Engineering Research Center for Antimicrobial Agent and Immunotechnology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Gen Lu
- Department of Respiration, Affiliated Guangzhou Women and Children's Hospital, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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22
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Lakdawala SS, Fodor E, Subbarao K. Moving On Out: Transport and Packaging of Influenza Viral RNA into Virions. Annu Rev Virol 2017; 3:411-427. [PMID: 27741407 DOI: 10.1146/annurev-virology-110615-042345] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Influenza A viruses bear an eight-segmented single-stranded negative-sense RNA genome that is replicated in the nucleus. Newly synthesized viral RNA (vRNA) segments are exported from the nucleus and transported to the plasma membrane for packaging into progeny virions. Influenza viruses exploit many host proteins during these events, and this is the portion of the viral life cycle when genetic reassortment among influenza viruses occurs. Reassortment among influenza A viruses allows viruses to expand their host range, virulence, and pandemic potential. This review covers recent studies on the export of vRNAs from the nucleus and their transport through the cytoplasm, progressive assembly, and packaging into progeny virus particles. Understanding these events and the constraints on genetic reassortment has implications for assessment of the pandemic potential of newly emerged influenza viruses, for vaccine production, for determination of viral fitness, and for identification of novel therapeutic targets.
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Affiliation(s)
- Seema S Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Kanta Subbarao
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892;
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Hu Y, Sneyd H, Dekant R, Wang J. Influenza A Virus Nucleoprotein: A Highly Conserved Multi-Functional Viral Protein as a Hot Antiviral Drug Target. Curr Top Med Chem 2017; 17:2271-2285. [PMID: 28240183 DOI: 10.2174/1568026617666170224122508] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 07/13/2016] [Accepted: 07/16/2016] [Indexed: 01/25/2023]
Abstract
Prevention and treatment of influenza virus infection is an ongoing unmet medical need. Each year, thousands of deaths and millions of hospitalizations are attributed to influenza virus infection, which poses a tremendous health and economic burden to the society. Aside from the annual influenza season, influenza viruses also lead to occasional influenza pandemics as a result of emerging or re-emerging influenza strains. Influenza viruses are RNA viruses that exist in quasispecies, meaning that they have a very diverse genetic background. Such a feature creates a grand challenge in devising therapeutic intervention strategies to inhibit influenza virus replication, as a single agent might not be able to inhibit all influenza virus strains. Both classes of currently approved anti-influenza drugs have limitations: the M2 channel blockers amantadine and rimantadine are no longer recommended for use in the U.S. due to predominant drug resistance, and resistance to the neuraminidase inhibitor oseltamivir is continuously on the rise. In pursuing the next generation of antiviral drugs with broad-spectrum activity and higher genetic barrier of drug resistance, the influenza virus nucleoprotein (NP) stands out as a high-profile drug target. This review summarizes recent developments in designing inhibitors targeting influenza NP and their mechanisms of action.
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Affiliation(s)
- Yanmei Hu
- Department of Pharmacology and Toxicology, College of Pharmacy, the University of Arizona, Tucson, AZ, United States
| | - Hannah Sneyd
- Department of Pharmacology and Toxicology, College of Pharmacy, the University of Arizona, Tucson, AZ, United States
| | - Raphael Dekant
- Department of Pharmacology and Toxicology, College of Pharmacy, the University of Arizona, Tucson, AZ, United States
| | - Jun Wang
- Department of Pharmacology and Toxicology, College of Pharmacy, the University of Arizona, Tucson, AZ, United States
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van de Wakker SI, Fischer MJ, Oosting RS. New drug-strategies to tackle viral-host interactions for the treatment of influenza virus infections. Eur J Pharmacol 2017; 809:178-190. [DOI: 10.1016/j.ejphar.2017.05.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 04/24/2017] [Accepted: 05/19/2017] [Indexed: 12/13/2022]
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Chen L, Wang C, Luo J, Li M, Liu H, Zhao N, Huang J, Zhu X, Ma G, Yuan G, He H. Amino Acid Substitution K470R in the Nucleoprotein Increases the Virulence of H5N1 Influenza A Virus in Mammals. Front Microbiol 2017; 8:1308. [PMID: 28744280 PMCID: PMC5504190 DOI: 10.3389/fmicb.2017.01308] [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: 04/07/2017] [Accepted: 06/28/2017] [Indexed: 12/21/2022] Open
Abstract
H5N1 is a highly pathogenic influenza A virus (IAV) and poses a major threat to the public health. The nucleoprotein (NP) has a multiple functions during the viral life cycle, however, the precise role of NP mutants in viral replication and pathogenicity is not completely understood. Here, we attempted to identify five residues in NP that may contribute to viral replication or pathogenicity. Of these, K227R, K229R, and K470R viruses were successfully rescued by reverse genetic, but the K91R and K198R viruses were not viable. A mini-genome assay demonstrated that the NP mutations K91R and K198R significantly decreased the polymerase activity. Moreover, these two mutations resulted in disrupted cellular localization in mammalian cells. Importantly, mutation at position 470 of NP significantly increased its virulence in vitro and in vivo. These findings demonstrated that the NP protein plays a major role in influenza virulence and pathogenicity, which adds to the knowledge of IAV virulence determinants and may benefit IAV surveillance.
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Affiliation(s)
- Lin Chen
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China.,University of the Chinese Academy of SciencesBeijing, China
| | - Chengmin Wang
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China
| | - Jing Luo
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China
| | - Meng Li
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China.,University of the Chinese Academy of SciencesBeijing, China
| | - Huimin Liu
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China.,University of the Chinese Academy of SciencesBeijing, China
| | - Na Zhao
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China.,University of the Chinese Academy of SciencesBeijing, China
| | - Jingjing Huang
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China
| | - Xili Zhu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of ScienceBeijing, China
| | - Guoyao Ma
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China.,University of the Chinese Academy of SciencesBeijing, China
| | - Guohui Yuan
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China
| | - Hongxuan He
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of SciencesBeijing, China
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Chutiwitoonchai N, Mano T, Kakisaka M, Sato H, Kondoh Y, Osada H, Kotani O, Yokoyama M, Sato H, Aida Y. Inhibition of CRM1-mediated nuclear export of influenza A nucleoprotein and nuclear export protein as a novel target for antiviral drug development. Virology 2017; 507:32-39. [PMID: 28399435 PMCID: PMC7111614 DOI: 10.1016/j.virol.2017.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/31/2017] [Accepted: 04/03/2017] [Indexed: 12/18/2022]
Abstract
An anti-influenza compound, DP2392-E10 based on inhibition of the nuclear export function of the viral nucleoprotein-nuclear export signal 3 (NP-NES3) domain was successfully identified by our previous high-throughput screening system. Here, we demonstrated that DP2392-E10 exerts its antiviral effect by inhibiting replication of a broad range of influenza A subtypes. In regard to the molecular mechanism, we revealed that DP2392-E10 inhibits nuclear export of both viral NP and nuclear export protein (NEP). More specifically, in vitro pull-down assays revealed that DP2392-E10 directly binds cellular CRM1, which mediates nuclear export of NP and NEP. In silico docking suggested that DP2392-E10 binds at a region close to the HEAT9 and HEAT10 domains of CRM1. Together, these results indicate that the CRM1-mediated nuclear export function of influenza virus represents a new potential target for antiviral drug development, and also provide a core structure for a novel class of inhibitors that target this function.
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Affiliation(s)
| | - Takafumi Mano
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Michinori Kakisaka
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hirotaka Sato
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yasumitsu Kondoh
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Osada
- Chemical Biology Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Osamu Kotani
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Masaru Yokoyama
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Hironori Sato
- Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, 4-7-1 Gakuen, Musashimurayama, Tokyo 208-0011, Japan
| | - Yoko Aida
- Viral Infectious Disease Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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Mutations in matrix protein 1 and nucleoprotein caused human-specific defects in nuclear exportation and viral assembly of an avian influenza H7N1 virus. Virus Res 2017; 238:49-62. [DOI: 10.1016/j.virusres.2017.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 04/26/2017] [Accepted: 05/24/2017] [Indexed: 12/13/2022]
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Abstract
Influenza A virus (IAV) RNA segments are individually packaged with viral nucleoprotein (NP) and RNA polymerases to form a viral ribonucleoprotein (vRNP) complex. We previously reported that NP is a monoubiquitinated protein which can be deubiquitinated by a cellular ubiquitin protease, USP11. In this study, we identified an E3 ubiquitin ligase, CNOT4 (Ccr4-Not transcription complex subunit 4), which can ubiquitinate NP. We found that the levels of viral RNA, protein, viral particles, and RNA polymerase activity in CNOT4 knockdown cells were lower than those in the control cells upon IAV infection. Conversely, overexpression of CNOT4 rescued viral RNP activity. In addition, CNOT4 interacted with the NP in the cell. An in vitro ubiquitination assay also showed that NP could be ubiquitinated by in vitro-translated CNOT4, but ubiquitination did not affect the protein stability of NP. Significantly, CNOT4 increased NP ubiquitination, whereas USP11 decreased it. Mass spectrometry analysis of ubiquitinated NP revealed multiple ubiquitination sites on the various lysine residues of NP. Three of these, K184, K227, and K273, are located on the RNA-binding groove of NP. Mutations of these sites to arginine reduced viral RNA replication. These results indicate that CNOT4 is a ubiquitin ligase of NP, and ubiquitination of NP plays a positive role in viral RNA replication. Influenza virus, particularly influenza A virus, causes severe and frequent outbreaks among human and avian species. Finding potential target sites for antiviral agents is of utmost importance from the public health point of view. We previously found that viral nucleoprotein (NP) is ubiquitinated, and ubiquitination enhances viral RNA replication. In this study, we found a cellular ubiquitin ligase, CNOT4, capable of ubiquitinating NP. The ubiquitination sites are scattered on the surface of the NP molecule, which is critical for RNA replication. CNOT4 and a ubiquitin protease, USP11, together regulate the extent of NP ubiquitination and thereby the efficiency of RNA replication. This study thus identifies a potential antiviral target site and reveals a novel posttranslational mechanism for regulating viral replication. This represents a novel finding in the literature of influenza virus research.
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Li R, Liu T, Liu M, Chen F, Liu S, Yang J. Anti-influenza A Virus Activity of Dendrobine and Its Mechanism of Action. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:3665-3674. [PMID: 28417634 DOI: 10.1021/acs.jafc.7b00276] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Dendrobine, a major component of Dendrobium nobile, increasingly draws attention for its wide applications in health care. Here we explore potential effects of dendrobine against influenza A virus and elucidate the underlying mechanism. Our results indicated that dendrobine possessed antiviral activity against influenza A viruses, including A/FM-1/1/47 (H1N1), A/Puerto Rico/8/34 H274Y (H1N1), and A/Aichi/2/68 (H3N2) with IC50 values of 3.39 ± 0.32, 2.16 ± 0.91, 5.32 ± 1.68 μg/mL, respectively. Mechanism studies revealed that dendrobine inhibited early steps in the viral replication cycle. Notably, dendrobine could bind to the highly conserved region of viral nucleoprotein (NP), subsequently restraining nuclear export of viral NP and its oligomerization. In conclusion, dendrobine shows potential to be developed as a promising agent to treat influenza virus infection. More importantly, the results provide invaluable information for the full application of the Traditional Chinese Medicine named "Shi Hu".
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Affiliation(s)
- Richan Li
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University , Guangzhou 510515, China
| | - Teng Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University , Guangzhou 510515, China
| | - Miaomiao Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University , Guangzhou 510515, China
| | - Feimin Chen
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University , Guangzhou 510515, China
| | - Shuwen Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University , Guangzhou 510515, China
| | - Jie Yang
- Guangdong Provincial Key Laboratory of New Drug Screening, Guangzhou Key laboratory of Drug Research for Emerging Virus Prevention and Treatment, School of Pharmaceutical Sciences, Southern Medical University , Guangzhou 510515, China
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The Short Form of the Zinc Finger Antiviral Protein Inhibits Influenza A Virus Protein Expression and Is Antagonized by the Virus-Encoded NS1. J Virol 2017; 91:JVI.01909-16. [PMID: 27807230 DOI: 10.1128/jvi.01909-16] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 10/27/2016] [Indexed: 12/25/2022] Open
Abstract
Zinc finger antiviral protein (ZAP) is a host factor that specifically inhibits the replication of certain viruses. There are two ZAP isoforms arising from alternative splicing, which differ only at the C termini. It was recently reported that the long isoform (ZAPL) promotes proteasomal degradation of influenza A virus (IAV) proteins PA and PB2 through the C-terminal poly(ADP-ribose) polymerase (PARP) domain, which is missing in the short form (ZAPS), and that this antiviral activity is antagonized by the viral protein PB1. Here, we report that ZAP inhibits IAV protein expression in a PARP domain-independent manner. Overexpression of ZAPS inhibited the expression of PA, PB2, and neuraminidase (NA), and downregulation of the endogenous ZAPS enhanced their expression. We show that ZAPS inhibited PB2 protein expression by reducing the encoding viral mRNA levels and repressing its translation. However, downregulation of ZAPS only modestly enhanced the early stage of viral replication. We provide evidence showing that the antiviral activity of ZAPS is antagonized by the viral protein NS1. A recombinant IAV carrying an NS1 mutant that lost the ZAPS-antagonizing activity replicated better in ZAPS-deficient cells. We further provide evidence suggesting that NS1 antagonizes ZAPS by inhibiting its binding to target mRNA. These results uncover a distinct mechanism underlying the interactions between ZAP and IAV. IMPORTANCE ZAP is a host antiviral factor that has been extensively reported to inhibit the replication of certain viruses by repressing the translation and promoting the degradation of the viral mRNAs. There are two ZAP isoforms, ZAPL and ZAPS. ZAPL was recently reported to promote IAV protein degradation through the PARP domain. Whether ZAPS, which lacks the PARP domain, inhibits IAV and the underlying mechanisms remained to be determined. Here, we show that ZAPS posttranscriptionally inhibits IAV protein expression. This antiviral activity of ZAP is antagonized by the viral protein NS1. The fact that ZAP uses two distinct mechanisms to inhibit IAV infection and that the virus evolved different antagonists suggests an important role of ZAP in the host effort to control IAV infection and the importance of the threat of ZAP to the virus. The results reported here help us to comprehensively understand the interactions between ZAP and IAV.
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31
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Li J, Zheng W, Hou L, Chen C, Fan W, Qu H, Jiang J, Liu J, Gao GF, Zhou J, Sun L, Liu W. Differential nucleocytoplasmic shuttling of the nucleoprotein of influenza a viruses and association with host tropism. Cell Microbiol 2016; 19. [DOI: 10.1111/cmi.12692] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 10/13/2016] [Accepted: 11/02/2016] [Indexed: 01/01/2023]
Affiliation(s)
- Jing Li
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
| | - Weinan Zheng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
| | - Lidan Hou
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- China Institute of Veterinary Drug Control; Beijing China
| | - Can Chen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Wenhui Fan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
| | - Hongren Qu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
| | - Jingwen Jiang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- School of Life Sciences; University of Science and Technology of China; Hefei China
| | - Jinhua Liu
- Key Laboratory of Zoonosis of Ministry of Agriculture, College of Veterinary Medicine; China Agricultural University; Beijing China
| | - George F. Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
- Beijing Institutes of Life Science; Chinese Academy of Sciences; Beijing China
- Office of Director-General; Chinese Center for Disease Control and Prevention; Beijing China
| | - Jiyong Zhou
- College of Veterinary Medicine; Nanjing Agricultural University; Nanjing China
| | - Lei Sun
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Wenjun Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology; Institute of Microbiology, Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
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32
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Antiviral activity of KR-23502 targeting nuclear export of influenza B virus ribonucleoproteins. Antiviral Res 2016; 134:77-88. [DOI: 10.1016/j.antiviral.2016.07.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 07/24/2016] [Accepted: 07/26/2016] [Indexed: 11/22/2022]
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33
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Chutiwitoonchai N, Aida Y. NXT1, a Novel Influenza A NP Binding Protein, Promotes the Nuclear Export of NP via a CRM1-Dependent Pathway. Viruses 2016; 8:E209. [PMID: 27483302 PMCID: PMC4997571 DOI: 10.3390/v8080209] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 12/31/2022] Open
Abstract
Influenza remains a serious worldwide public health problem. After infection, viral genomic RNA is replicated in the nucleus and packed into viral ribonucleoprotein, which will then be exported to the cytoplasm via a cellular chromosome region maintenance 1 (CRM1)-dependent pathway for further assembly and budding. However, the nuclear export mechanism of influenza virus remains controversial. Here, we identify cellular nuclear transport factor 2 (NTF2)-like export protein 1 (NXT1) as a novel binding partner of nucleoprotein (NP) that stimulates NP-mediated nuclear export via the CRM1-dependent pathway. NXT1-knockdown cells exhibit decreased viral replication kinetics and nuclear accumulated viral RNA and NP. By contrast, NXT1 overexpression promotes nuclear export of NP in a CRM1-dependent manner. Pull-down assays suggest the formation of an NXT1, NP, and CRM1 complex, and demonstrate that NXT1 binds to the C-terminal region of NP. These findings reveal a distinct mechanism for nuclear export of the influenza virus and identify the NXT1/NP interaction as a potential target for antiviral drug development.
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Affiliation(s)
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama 351-0198, Japan.
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34
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Pohl MO, Lanz C, Stertz S. Late stages of the influenza A virus replication cycle-a tight interplay between virus and host. J Gen Virol 2016; 97:2058-2072. [PMID: 27449792 DOI: 10.1099/jgv.0.000562] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After successful infection and replication of its genome in the nucleus of the host cell, influenza A virus faces several challenges before newly assembled viral particles can bud off from the plasma membrane, giving rise to a new infectious virus. The viral ribonucleoprotein (vRNP) complexes need to exit from the nucleus and be transported to the virus assembly sites at the plasma membrane. Moreover, they need to be bundled to ensure the incorporation of precisely one of each of the eight viral genome segments into newly formed viral particles. Similarly, viral envelope glycoproteins and other viral structural proteins need to be targeted to virus assembly sites for viral particles to form and bud off from the plasma membrane. During all these steps influenza A virus heavily relies on a tight interplay with its host, exploiting host-cell proteins for its own purposes. In this review, we summarize current knowledge on late stages of the influenza virus replication cycle, focusing on the role of host-cell proteins involved in this process.
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Affiliation(s)
- Marie O Pohl
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
| | - Caroline Lanz
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
| | - Silke Stertz
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
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Host Protein Moloney Leukemia Virus 10 (MOV10) Acts as a Restriction Factor of Influenza A Virus by Inhibiting the Nuclear Import of the Viral Nucleoprotein. J Virol 2016; 90:3966-3980. [PMID: 26842467 DOI: 10.1128/jvi.03137-15] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Accepted: 01/25/2016] [Indexed: 01/06/2023] Open
Abstract
UNLABELLED The viral ribonucleoprotein (vRNP) complex of influenza A viruses (IAVs) contains an RNA-dependent RNA polymerase complex (RdRp) and nucleoprotein (NP) and is the functional unit for viral RNA transcription and replication. The vRNP complex is an important determinant of virus pathogenicity and host adaptation, implying that its function can be affected by host factors. In our study, we identified host protein Moloney leukemia virus 10 (MOV10) as an inhibitor of IAV replication, since depletion of MOV10 resulted in a significant increase in virus yield. MOV10 inhibited the polymerase activity in a minigenome system through RNA-mediated interaction with the NP subunit of vRNP complex. Importantly, we found that the interaction between MOV10 and NP prevented the binding of NP to importin-α, resulting in the retention of NP in the cytoplasm. Both the binding of MOV10 to NP and its inhibitory effect on polymerase activity were independent of its helicase activity. These results suggest that MOV10 acts as an anti-influenza virus factor through specifically inhibiting the nuclear transportation of NP and subsequently inhibiting the function of the vRNP complex. IMPORTANCE The interaction between the influenza virus vRNP complex and host factors is a major determinant of viral tropism and pathogenicity. Our study identified MOV10 as a novel host restriction factor for the influenza virus life cycle since it inhibited the viral growth rate. Conversely, importin-α has been shown as a determinant for influenza tropism and a positive regulator for viral polymerase activity in mammalian cells but not in avian cells. MOV10 disrupted the interaction between NP and importin-α, suggesting that MOV10 could also be an important host factor for influenza virus transmission and pathogenicity. Importantly, as an interferon (IFN)-inducible protein, MOV10 exerted a novel mechanism for IFNs to inhibit the replication of influenza viruses. Furthermore, our study potentially provides a new drug design strategy, the use of molecules that mimic the antiviral mechanism of MOV10.
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A high-throughput screening system targeting the nuclear export pathway via the third nuclear export signal of influenza A virus nucleoprotein. Virus Res 2016; 217:23-31. [PMID: 26948263 DOI: 10.1016/j.virusres.2016.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/07/2016] [Indexed: 11/22/2022]
Abstract
Two classes of antiviral drugs, M2 channel inhibitors and neuraminidase (NA) inhibitors, are currently approved for the treatment of influenza; however, the development of resistance against these agents limits their efficacy. Therefore, the identification of new targets and the development of new antiviral drugs against influenza are urgently needed. The third nuclear export signal (NES3) of nucleoprotein (NP) is the most important for viral replication among seven NESs encoded by four viral proteins, NP, M1, NS1, and NS2. NP-NES3 is critical for the nuclear export of NP, and targeting NP-NES3 is therefore a promising strategy that may lead to the development of antiviral drugs. However, a high-throughput screening (HTS) system to identify inhibitors of NP nuclear export has not been established. Here, we developed a novel HTS system to evaluate the inhibitory effects of compounds on the nuclear export pathway mediated by NP-NES3 using a MDCK cell line stably expressing NP-NES3 fused to a green fluorescent protein from aequorea coerulescens (AcGFP-NP-NES3) and a cell imaging analyzer. This HTS system was used to screen a 9600-compound library, leading to the identification of several hit compounds with inhibitory activity against the nuclear export of AcGFP-NP-NES3. The present HTS system provides a useful strategy for the identification of inhibitors targeting the nuclear export of NP via its NES3 sequence.
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Human Heat shock protein 40 (Hsp40/DnaJB1) promotes influenza A virus replication by assisting nuclear import of viral ribonucleoproteins. Sci Rep 2016; 6:19063. [PMID: 26750153 PMCID: PMC4707480 DOI: 10.1038/srep19063] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/26/2015] [Indexed: 01/11/2023] Open
Abstract
A unique feature of influenza A virus (IAV) life cycle is replication of the viral genome in the host cell nucleus. The nuclear import of IAV genome is an indispensable step in establishing virus infection. IAV nucleoprotein (NP) is known to mediate the nuclear import of viral genome via its nuclear localization signals. Here, we demonstrate that cellular heat shock protein 40 (Hsp40/DnaJB1) facilitates the nuclear import of incoming IAV viral ribonucleoproteins (vRNPs) and is important for efficient IAV replication. Hsp40 was found to interact with NP component of IAV RNPs during early stages of infection. This interaction is mediated by the J domain of Hsp40 and N-terminal region of NP. Drug or RNAi mediated inhibition of Hsp40 resulted in reduced nuclear import of IAV RNPs, diminished viral polymerase function and attenuates overall viral replication. Hsp40 was also found to be required for efficient association between NP and importin alpha, which is crucial for IAV RNP nuclear translocation. These studies demonstrate an important role for cellular chaperone Hsp40/DnaJB1 in influenza A virus life cycle by assisting nuclear trafficking of viral ribonucleoproteins.
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38
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Kakisaka M, Sasaki Y, Yamada K, Kondoh Y, Hikono H, Osada H, Tomii K, Saito T, Aida Y. A Novel Antiviral Target Structure Involved in the RNA Binding, Dimerization, and Nuclear Export Functions of the Influenza A Virus Nucleoprotein. PLoS Pathog 2015. [PMID: 26222066 PMCID: PMC4519322 DOI: 10.1371/journal.ppat.1005062] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Developing antiviral therapies for influenza A virus (IAV) infection is an ongoing process because of the rapid rate of antigenic mutation and the emergence of drug-resistant viruses. The ideal strategy is to develop drugs that target well-conserved, functionally restricted, and unique surface structures without affecting host cell function. We recently identified the antiviral compound, RK424, by screening a library of 50,000 compounds using cell-based infection assays. RK424 showed potent antiviral activity against many different subtypes of IAV in vitro and partially protected mice from a lethal dose of A/WSN/1933 (H1N1) virus in vivo. Here, we show that RK424 inhibits viral ribonucleoprotein complex (vRNP) activity, causing the viral nucleoprotein (NP) to accumulate in the cell nucleus. In silico docking analysis revealed that RK424 bound to a small pocket in the viral NP. This pocket was surrounded by three functionally important domains: the RNA binding groove, the NP dimer interface, and nuclear export signal (NES) 3, indicating that it may be involved in the RNA binding, oligomerization, and nuclear export functions of NP. The accuracy of this binding model was confirmed in a NP-RK424 binding assay incorporating photo-cross-linked RK424 affinity beads and in a plaque assay evaluating the structure-activity relationship of RK424. Surface plasmon resonance (SPR) and pull-down assays showed that RK424 inhibited both the NP-RNA and NP-NP interactions, whereas size exclusion chromatography showed that RK424 disrupted viral RNA-induced NP oligomerization. In addition, in vitro nuclear export assays confirmed that RK424 inhibited nuclear export of NP. The amino acid residues comprising the NP pocket play a crucial role in viral replication and are highly conserved in more than 7,000 NP sequences from avian, human, and swine influenza viruses. Furthermore, we found that the NP pocket has a surface structure different from that of the pocket in host molecules. Taken together, these results describe a promising new approach to developing influenza virus drugs that target a novel pocket structure within NP. Influenza A virus nucleoprotein (NP) is a highly conserved multifunctional protein that plays an essential role in infection by all subtypes of influenza A virus, making it an attractive target for new antiviral drugs. NP regulates viral polymerase activity and transport of the viral genome into/from the host cell nucleus by forming the viral ribonucleoprotein complex (vRNP). Because NP regulates replication and transcription of the viral genome in addition to its role in nuclear export (all of which are essential for the production of viral progeny), it is a promising drug target. Here, we used the antiviral compound RK424 to identify a novel pocket structure within NP. This structure encompassed three different functional domains that are involved in the above-mentioned replication steps. RK424 inhibits viral genome replication/transcription and nuclear export of NP by destabilizing the NP oligomer and inhibiting the binding of chromosome region maintenance 1 (CRM1) to NP via nuclear export signal (NES) 3, which is located in close proximity to the NP pocket. Taken together, these findings suggest that this small NP pocket is a novel antiviral target.
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Affiliation(s)
| | - Yutaka Sasaki
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan
| | - Kazunori Yamada
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan
- Computational Biology Research Center (CBRC), National Institute of Advanced Industrial Science and Technology (AIST), Koto-ku, Tokyo, Japan
| | | | - Hirokazu Hikono
- Influenza and Prion Disease Research Center, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
| | - Hiroyuki Osada
- Chemical Biology Group, RIKEN CSRS, Wako, Saitama, Japan
| | - Kentaro Tomii
- Computational Biology Research Center (CBRC), National Institute of Advanced Industrial Science and Technology (AIST), Koto-ku, Tokyo, Japan
| | - Takehiko Saito
- Influenza and Prion Disease Research Center, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan
- * E-mail:
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Nucleocytoplasmic shuttling of influenza A virus proteins. Viruses 2015; 7:2668-82. [PMID: 26008706 PMCID: PMC4452925 DOI: 10.3390/v7052668] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 05/20/2015] [Indexed: 12/31/2022] Open
Abstract
Influenza viruses transcribe and replicate their genomes in the nuclei of infected host cells. The viral ribonucleoprotein (vRNP) complex of influenza virus is the essential genetic unit of the virus. The viral proteins play important roles in multiple processes, including virus structural maintenance, mediating nucleocytoplasmic shuttling of the vRNP complex, virus particle assembly, and budding. Nucleocytoplasmic shuttling of viral proteins occurs throughout the entire virus life cycle. This review mainly focuses on matrix protein (M1), nucleoprotein (NP), nonstructural protein (NS1), and nuclear export protein (NEP), summarizing the mechanisms of their nucleocytoplasmic shuttling and the regulation of virus replication through their phosphorylation to further understand the regulation of nucleocytoplasmic shuttling in host adaptation of the viruses.
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Phosphorylation controls the nuclear-cytoplasmic shuttling of influenza A virus nucleoprotein. J Virol 2015; 89:5822-34. [PMID: 25787277 DOI: 10.1128/jvi.00015-15] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 03/09/2015] [Indexed: 12/27/2022] Open
Abstract
UNLABELLED The nucleoprotein (NP) is a major component of the viral ribonucleoprotein (vRNP) complex. During the replication of influenza virus, the vRNP complex undergoes nuclear-cytoplasmic shuttling, during which NP serves as one of the determinants. To date, many phosphorylation sites on NP have been identified, but the biological functions of many of these phosphorylation sites remain unknown. In the present study, the functions of the phosphorylation sites S9, Y10, and Y296 were characterized. These residues are highly conserved, and their phosphorylation was essential for virus growth in cell culture and in a mouse model by regulating the activity of the viral polymerase and the nuclear-cytoplasmic shuttling of NP. The phosphorylation and dephosphorylation of S9 and Y10 controlled nuclear import of NP by affecting the binding affinity between NP and different isoforms of importin-α. In addition, the phosphorylation of Y296 caused nuclear retention of NP by reducing the interaction between NP and CRM1. Furthermore, tyrosine phosphorylation of NP during the early stage of virus infection was ablated when Y296 was mutated to F. However, at later stages of infection, it was weakened by the Y10F mutation. Taken together, the present data indicate that the phosphorylation and dephosphorylation of NP control the shuttling of NP between the nucleus and the cytoplasm during virus replication. IMPORTANCE It is well known that phosphorylation regulates the functions of viral proteins and the life cycle of influenza A virus. As NP is the most abundant protein in the vRNP complex of influenza A virus, several phosphorylation sites on this protein have been identified. However, the functions of these phosphorylation sites were unknown. The present study demonstrates that the phosphorylation status of these sites on NP can mediate its nuclear-cytoplasmic shuttling, which drives the trafficking of vRNP complexes in infected cells. The present data suggest that the phosphorylated residues of NP are multistep controllers of the virus life cycle and new targets for the design of anti-influenza drugs.
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Abstract
Influenza A viral ribonucleoprotein (vRNP) complexes comprise the eight genomic negative-sense RNAs, each of which is bound to multiple copies of the vRNP and a trimeric viral polymerase complex. The influenza virus life cycle centres on the vRNPs, which in turn rely on host cellular processes to carry out functions that are necessary for the successful completion of the virus life cycle. In this Review, we discuss our current knowledge about vRNP trafficking within host cells and the function of these complexes in the context of the virus life cycle, highlighting how structure contributes to function and the crucial interactions with host cell pathways, as well as on the information gaps that remain. An improved understanding of how vRNPs use host cell pathways is essential to identify mechanisms of virus pathogenicity, host adaptation and, ultimately, new targets for antiviral intervention.
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Chutiwitoonchai N, Kakisaka M, Yamada K, Aida Y. Comparative analysis of seven viral nuclear export signals (NESs) reveals the crucial role of nuclear export mediated by the third NES consensus sequence of nucleoprotein (NP) in influenza A virus replication. PLoS One 2014; 9:e105081. [PMID: 25119991 PMCID: PMC4132019 DOI: 10.1371/journal.pone.0105081] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/17/2014] [Indexed: 11/19/2022] Open
Abstract
The assembly of influenza virus progeny virions requires machinery that exports viral genomic ribonucleoproteins from the cell nucleus. Currently, seven nuclear export signal (NES) consensus sequences have been identified in different viral proteins, including NS1, NS2, M1, and NP. The present study examined the roles of viral NES consensus sequences and their significance in terms of viral replication and nuclear export. Mutation of the NP-NES3 consensus sequence resulted in a failure to rescue viruses using a reverse genetics approach, whereas mutation of the NS2-NES1 and NS2-NES2 sequences led to a strong reduction in viral replication kinetics compared with the wild-type sequence. While the viral replication kinetics for other NES mutant viruses were also lower than those of the wild-type, the difference was not so marked. Immunofluorescence analysis after transient expression of NP-NES3, NS2-NES1, or NS2-NES2 proteins in host cells showed that they accumulated in the cell nucleus. These results suggest that the NP-NES3 consensus sequence is mostly required for viral replication. Therefore, each of the hydrophobic (Φ) residues within this NES consensus sequence (Φ1, Φ2, Φ3, or Φ4) was mutated, and its viral replication and nuclear export function were analyzed. No viruses harboring NP-NES3 Φ2 or Φ3 mutants could be rescued. Consistent with this, the NP-NES3 Φ2 and Φ3 mutants showed reduced binding affinity with CRM1 in a pull-down assay, and both accumulated in the cell nucleus. Indeed, a nuclear export assay revealed that these mutant proteins showed lower nuclear export activity than the wild-type protein. Moreover, the Φ2 and Φ3 residues (along with other Φ residues) within the NP-NES3 consensus were highly conserved among different influenza A viruses, including human, avian, and swine. Taken together, these results suggest that the Φ2 and Φ3 residues within the NP-NES3 protein are important for its nuclear export function during viral replication.
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Affiliation(s)
| | | | - Kazunori Yamada
- Computational Biology Research Center, National Institute of Advanced Industrial Science and Technology, Koto, Tokyo, Japan
| | - Yoko Aida
- Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan
- * E-mail:
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Watanabe K, Shimizu T, Noda S, Tsukahara F, Maru Y, Kobayashi N. Nuclear export of the influenza virus ribonucleoprotein complex: Interaction of Hsc70 with viral proteins M1 and NS2. FEBS Open Bio 2014; 4:683-8. [PMID: 25161876 PMCID: PMC4141210 DOI: 10.1016/j.fob.2014.07.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 07/04/2014] [Accepted: 07/04/2014] [Indexed: 11/26/2022] Open
Abstract
The influenza virus replicates in the host cell nucleus, and the progeny viral ribonucleoprotein complex (vRNP) is exported to the cytoplasm prior to maturation. NS2 has a nuclear export signal that mediates the nuclear export of vRNP by the vRNP-M1-NS2 complex. We previously reported that the heat shock cognate 70 (Hsc70) protein binds to M1 protein and mediates vRNP export. However, the interactions among M1, NS2, and Hsc70 are poorly understood. In the present study, we demonstrate that Hsc70 interacts with M1 more strongly than with NS2 and competes with NS2 for M1 binding, suggesting an important role of Hsc70 in the nuclear export of vRNP.
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Affiliation(s)
- Ken Watanabe
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Teppei Shimizu
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Saiko Noda
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Fujiko Tsukahara
- Department of Pharmacology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Yoshiro Maru
- Department of Pharmacology, Tokyo Women's Medical University, School of Medicine, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Nobuyuki Kobayashi
- Laboratory of Molecular Biology of Infectious Agents, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan ; Central Research Center, AVSS Corporation, 1-22, Wakaba-machi, Nagasaki 852-8137, Japan
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Hutchinson EC, Fodor E. Transport of the influenza virus genome from nucleus to nucleus. Viruses 2013; 5:2424-46. [PMID: 24104053 PMCID: PMC3814596 DOI: 10.3390/v5102424] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/24/2013] [Accepted: 09/26/2013] [Indexed: 11/24/2022] Open
Abstract
The segmented genome of an influenza virus is encapsidated into ribonucleoprotein complexes (RNPs). Unusually among RNA viruses, influenza viruses replicate in the nucleus of an infected cell, and their RNPs must therefore recruit host factors to ensure transport across a number of cellular compartments during the course of an infection. Recent studies have shed new light on many of these processes, including the regulation of nuclear export, genome packaging, mechanisms of virion assembly and viral entry and, in particular, the identification of Rab11 on recycling endosomes as a key mediator of RNP transport and genome assembly. This review uses these recent gains in understanding to describe in detail the journey of an influenza A virus RNP from its synthesis in the nucleus through to its entry into the nucleus of a new host cell.
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Affiliation(s)
- Edward C Hutchinson
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
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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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Michael P, Brabant D, Bleiblo F, Ramana CV, Rutherford M, Khurana S, Tai T, Kumar A, Kumar A. Influenza A induced cellular signal transduction pathways. J Thorac Dis 2013; 5 Suppl 2:S132-41. [PMID: 23977434 PMCID: PMC3747532 DOI: 10.3978/j.issn.2072-1439.2013.07.42] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 07/25/2013] [Indexed: 12/28/2022]
Abstract
Influenza A is a negative sense single stranded RNA virus that belongs to the Orthomyxoviridae Family. This enveloped virus contains 8 segments of viral RNA which encodes 11 viral proteins. Influenza A infects humans and is the causative agent of the flu. Annually it infects approximately 5% to 15% of the population world wide and results in an estimated 250,000 to 500,000 deaths a year. The nature of influenza A replication results in a high mutation rate which results in the need for seasonal vaccinations. In addition the zoonotic nature of the influenza virus allows for recombination of viral segments from different strains creating new variants that have not been encountered before. This type of mutation is the method by which pandemic strains of the flu arises. Infection with influenza results in a respiratory illness that for most individuals is self limiting. However in susceptible populations which include individuals with pre-existing pulmonary or cardiac conditions, the very young and the elderly fatal complications may arise. The most serious of these is the development of viral pneumonia which may be accompanied by secondary bacterial infections. Progression of pneumonia leads to the development of acute respiratory distress syndrome (ARDS), acute lung injury (ALI) and potentially respiratory failure. This progression is a combined effect of the host immune system response to influenza infection and the viral infection itself. This review will focus on molecular aspects of viral replication in alveolar cells and their response to infection. The response of select innate immune cells and their contribution to viral clearance and lung epithelial damage will also be discussed. Molecular aspects of antiviral response in the cells in particular the protein kinase RNA dependent response, and the oligoadenylate synthetase RNAse L system in relation to influenza infection.
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Affiliation(s)
- Paul Michael
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Program, Laurentian University, Sudbury, P3E 2C6, ON, Canada
| | - Danielle Brabant
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Program, Laurentian University, Sudbury, P3E 2C6, ON, Canada
| | - Farag Bleiblo
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Program, Laurentian University, Sudbury, P3E 2C6, ON, Canada
- Department of Biology, University of Benghazi, Benghazi, Libya
| | | | - Michael Rutherford
- Department of Pathology, Health Sciences North, Sudbury, P3E 5J1, ON, Canada
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, P3E 2C6, ON, Canada
| | - Sandhya Khurana
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Program, Laurentian University, Sudbury, P3E 2C6, ON, Canada
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, P3E 2C6, ON, Canada
| | - T.C. Tai
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Program, Laurentian University, Sudbury, P3E 2C6, ON, Canada
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, P3E 2C6, ON, Canada
| | - Anand Kumar
- Section of Critical Care Medicine, University of Manitoba, Winnipeg, R3A 1R9, MB, Canada
| | - Aseem Kumar
- Department of Chemistry and Biochemistry and the Biomolecular Sciences Program, Laurentian University, Sudbury, P3E 2C6, ON, Canada
- Medical Sciences Division, Northern Ontario School of Medicine, Sudbury, P3E 2C6, ON, Canada
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Adaptation of avian influenza A virus polymerase in mammals to overcome the host species barrier. J Virol 2013; 87:7200-9. [PMID: 23616660 DOI: 10.1128/jvi.00980-13] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Avian influenza A viruses, such as the highly pathogenic avian H5N1 viruses, sporadically enter the human population but often do not transmit between individuals. In rare cases, however, they establish a new lineage in humans. In addition to well-characterized barriers to cell entry, one major hurdle which avian viruses must overcome is their poor polymerase activity in human cells. There is compelling evidence that these viruses overcome this obstacle by acquiring adaptive mutations in the polymerase subunits PB1, PB2, and PA and the nucleoprotein (NP) as well as in the novel polymerase cofactor nuclear export protein (NEP). Recent findings suggest that synthesis of the viral genome may represent the major defect of avian polymerases in human cells. While the precise mechanisms remain to be unveiled, it appears that a broad spectrum of polymerase adaptive mutations can act collectively to overcome this defect. Thus, identification and monitoring of emerging adaptive mutations that further increase polymerase activity in human cells are critical to estimate the pandemic potential of avian viruses.
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Structure-based discovery of the novel antiviral properties of naproxen against the nucleoprotein of influenza A virus. Antimicrob Agents Chemother 2013; 57:2231-42. [PMID: 23459490 DOI: 10.1128/aac.02335-12] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The nucleoprotein (NP) binds the viral RNA genome and associates with the polymerase in a ribonucleoprotein complex (RNP) required for transcription and replication of influenza A virus. NP has no cellular counterpart, and the NP sequence is highly conserved, which led to considering NP a hot target in the search for antivirals. We report here that monomeric nucleoprotein can be inhibited by a small molecule binding in its RNA binding groove, resulting in a novel antiviral against influenza A virus. We identified naproxen, an anti-inflammatory drug that targeted the nucleoprotein to inhibit NP-RNA association required for NP function, by virtual screening. Further docking and molecular dynamics (MD) simulations identified in the RNA groove two NP-naproxen complexes of similar levels of interaction energy. The predicted naproxen binding sites were tested using the Y148A, R152A, R355A, and R361A proteins carrying single-point mutations. Surface plasmon resonance, fluorescence, and other in vitro experiments supported the notion that naproxen binds at a site identified by MD simulations and showed that naproxen competed with RNA binding to wild-type (WT) NP and protected active monomers of the nucleoprotein against proteolytic cleavage. Naproxen protected Madin-Darby canine kidney (MDCK) cells against viral challenges with the H1N1 and H3N2 viral strains and was much more effective than other cyclooxygenase inhibitors in decreasing viral titers of MDCK cells. In a mouse model of intranasal infection, naproxen treatment decreased the viral titers in mice lungs. In conclusion, naproxen is a promising lead compound for novel antivirals against influenza A virus that targets the nucleoprotein in its RNA binding groove.
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Abstract
Influenza virus is a major human and animal pathogen causing seasonal epidemics and occasional pandemics in the human population that are associated with significant morbidity and mortality. Influenza A virus, a member of the orthomyxovirus family, contains an RNA genome with a coding capacity for a limited number of proteins. In addition to ensuring the structural integrity of virions, these viral proteins facilitate the replication of virus in the host cell. Consequently, viral proteins often evolve to perform multiple functions, the influenza A virus nuclear export protein (NEP) (also referred to as non-structural protein 2, or NS2) being an emerging example. NEP was originally implicated in mediating the nuclear export of viral ribonucleoprotein (RNP) complexes, which are synthesized in the infected cell nucleus and are assembled into progeny virions at the cell membrane. However, since then, new and unexpected roles for NEP during the influenza virus life cycle have started to emerge. These recent studies have shown NEP to be involved in regulating the accumulation of viral genomic vRNA and antigenomic cRNA as well as viral mRNA synthesized by the viral RNA-dependent RNA polymerase. Subsequently, this regulation of viral RNA transcription and replication by NEP was shown to be an important factor in the adaptation of highly pathogenic avian H5N1 influenza viruses to the mammalian host. Unexpectedly, NEP has also been implicated in recruiting a cellular ATPase to the cell membrane to aid the efficient release of budding virions. Accordingly, NEP is proposed to play multiple biologically important roles during the influenza virus life cycle.
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Affiliation(s)
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Cianci C, Gerritz SW, Deminie C, Krystal M. Influenza nucleoprotein: promising target for antiviral chemotherapy. Antivir Chem Chemother 2012; 23:77-91. [PMID: 22837443 DOI: 10.3851/imp2235] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/04/2012] [Indexed: 12/25/2022] Open
Abstract
In the search for new anti-influenza agents, the viral polymerase has often been targeted due to the involvement of multiple conserved proteins and their distinct activities. Polymerase associates with each of the eight singled-stranded negative-sense viral RNA segments. These transcriptionally competent segments are coated with multiple copies of nucleoprotein (NP) to form the ribonucleoprotein. NP is an abundant essential protein, possessing operative and structural functions, and participating in genome organization, nuclear trafficking and RNA transcription and replication. This review examines the NP structure and function, and explores NP as an emerging target for anti-influenza drug development, focusing on recently discovered aryl piperazine amide inhibitor chemotypes.
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