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Brogaard L, Heegaard PMH, Larsen LE, Skovgaard K. Pulmonary MicroRNA expression after heterologous challenge with swine influenza A virus (H1N2) in immunized and non-immunized pigs. Virology 2024; 596:110117. [PMID: 38797064 DOI: 10.1016/j.virol.2024.110117] [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: 02/23/2024] [Revised: 05/15/2024] [Accepted: 05/21/2024] [Indexed: 05/29/2024]
Abstract
MicroRNAs (miRNAs) contribute to post-transcriptional modulation of the host response during influenza A virus (IAV) infection and may be involved in shaping disease severity. Differential disease severity was achieved in two groups of pigs by immunization of one group with a commercial swine IAV vaccine prior to heterologous IAV (H1N2) challenge of both groups. Lung tissue was harvested 1, 3, and 14 days after challenge and miRNA expression was quantified. Gene Ontology term enrichment analysis was employed to examine the functional relevance of genes potentially regulated by differentially expressed miRNAs in pigs with varying degrees of disease severity following IAV infection. Results suggested that the miRNA response associated with less severe disease may modulate host mechanisms essential for viral life cycle, e.g. transcription, translation, and protein trafficking. During more severe disease, miRNA-mediated regulation may focus on dampening virus-specific processes e.g. virion assembly and viral protein processing, and controlling host metabolism.
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Affiliation(s)
- Louise Brogaard
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - Peter M H Heegaard
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Lars E Larsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Kerstin Skovgaard
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Kongens Lyngby, Denmark
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2
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Shrikondawar AN, Chennoju K, Ghosh DK, Ranjan A. Identification and characterization of nuclear localization signals in the circumsporozoite protein of Plasmodium falciparum. FEBS Lett 2024; 598:801-817. [PMID: 38369616 DOI: 10.1002/1873-3468.14829] [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: 11/09/2023] [Revised: 12/30/2023] [Accepted: 01/15/2024] [Indexed: 02/20/2024]
Abstract
Secretory proteins of Plasmodium exhibit differential spatial and functional activity within the host cell nucleus. However, the nuclear localization signals (NLSs) for these proteins remain largely uncharacterized. In this study, we have identified and characterized two NLSs in the circumsporozoite protein of Plasmodium falciparum (Pf-CSP). Both NLSs in the Pf-CSP contain clusters of lysine and arginine residues essential for specific interactions with the conserved tryptophan and asparagine residues of importin-α, facilitating nuclear translocation of Pf-CSP. While the two NLSs of Pf-CSP function independently and are both crucial for nuclear localization, a single NLS of Pf-CSP leads to weak nuclear localization. These findings shed light on the mechanism of nuclear penetrability of secretory proteins of Plasmodium proteins.
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Affiliation(s)
- Akshaykumar Nanaji Shrikondawar
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
- Graduate Studies, Regional Centre for Biotechnology, Faridabad, India
| | - Kiranmai Chennoju
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | | | - Akash Ranjan
- Computational and Functional Genomics Group, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
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3
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Song MS, Lee DK, Lee CY, Park SC, Yang J. Host Subcellular Organelles: Targets of Viral Manipulation. Int J Mol Sci 2024; 25:1638. [PMID: 38338917 PMCID: PMC10855258 DOI: 10.3390/ijms25031638] [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: 01/04/2024] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
Viruses have evolved sophisticated mechanisms to manipulate host cell processes and utilize intracellular organelles to facilitate their replication. These complex interactions between viruses and cellular organelles allow them to hijack the cellular machinery and impair homeostasis. Moreover, viral infection alters the cell membrane's structure and composition and induces vesicle formation to facilitate intracellular trafficking of viral components. However, the research focus has predominantly been on the immune response elicited by viruses, often overlooking the significant alterations that viruses induce in cellular organelles. Gaining a deeper understanding of these virus-induced cellular changes is crucial for elucidating the full life cycle of viruses and developing potent antiviral therapies. Exploring virus-induced cellular changes could substantially improve our understanding of viral infection mechanisms.
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Affiliation(s)
- Min Seok Song
- Department of Physiology and Convergence Medical Science, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Dong-Kun Lee
- Department of Physiology and Convergence Medical Science, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Chung-Young Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Sang-Cheol Park
- Artificial Intelligence and Robotics Laboratory, Myongji Hospital, Goyang 10475, Republic of Korea
| | - Jinsung Yang
- Department of Biochemistry and Convergence Medical Science, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea
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Sabsay KR, te Velthuis AJW. Negative and ambisense RNA virus ribonucleocapsids: more than protective armor. Microbiol Mol Biol Rev 2023; 87:e0008223. [PMID: 37750733 PMCID: PMC10732063 DOI: 10.1128/mmbr.00082-23] [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: 09/27/2023] Open
Abstract
SUMMARYNegative and ambisense RNA viruses are the causative agents of important human diseases such as influenza, measles, Lassa fever, and Ebola hemorrhagic fever. The viral genome of these RNA viruses consists of one or more single-stranded RNA molecules that are encapsidated by viral nucleocapsid proteins to form a ribonucleoprotein complex (RNP). This RNP acts as protection, as a scaffold for RNA folding, and as the context for viral replication and transcription by a viral RNA polymerase. However, the roles of the viral nucleoproteins extend beyond these functions during the viral infection cycle. Recent advances in structural biology techniques and analysis methods have provided new insights into the formation, function, dynamics, and evolution of negative sense virus nucleocapsid proteins, as well as the role that they play in host innate immune responses against viral infection. In this review, we discuss the various roles of nucleocapsid proteins, both in the context of RNPs and in RNA-free states, as well as the open questions that remain.
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Affiliation(s)
- Kimberly R. Sabsay
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Aartjan J. W. te Velthuis
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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5
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Nguyen NLT, Wu W, Panté N. Contribution of the Nuclear Localization Sequences of Influenza A Nucleoprotein to the Nuclear Import of the Influenza Genome in Infected Cells. Viruses 2023; 15:1641. [PMID: 37631984 PMCID: PMC10459959 DOI: 10.3390/v15081641] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Replication of the RNA genome of influenza A virus occurs in the nucleus of infected cells. The influenza nucleoprotein (NP) associated with the viral RNA into ribonucleoprotein complexes (vRNPs) is involved in the nuclear import of the viral genome. NP has two nuclear localization sequences (NLSs), NLS1 and NLS2. Most studies have concentrated on the role of NP's NLSs using in vitro-assembled or purified vRNPs, which may differ from incoming vRNPs released in the cytoplasm during an infection. Here, we study the contribution of the NP's NLSs to the nuclear import of vRNPs in a cell culture model system for influenza infection: human lung carcinoma cells infected with viruses containing NP-carrying mutations in NLS1 or NLS2 (NLS2MT), generated by reverse genetics. We found that cells infected with these mutant viruses were defective in the nuclear import of incoming vRNPs and produced reduced amounts of newly synthesized NP, newly assembled vRNP, and progeny virus. In addition, NLS2MT-infected cells were also defective in the nucleolar accumulation of NP, confirming the nucleolar localization role of NLS2. Our findings indicate that both NLS1 and NLS2 have to be present for successful infection and demonstrate the crucial role of these two NLSs in the infection cycle of the influenza A virus.
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Affiliation(s)
| | | | - Nelly Panté
- Department of Zoology and Life Sciences Institute, University of British Columbia, Vancouver, BC V6T 1Z3, Canada; (N.L.T.N.); (W.W.)
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6
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Kumari R, Sharma SD, Kumar A, Ende Z, Mishina M, Wang Y, Falls Z, Samudrala R, Pohl J, Knight PR, Sambhara S. Antiviral Approaches against Influenza Virus. Clin Microbiol Rev 2023; 36:e0004022. [PMID: 36645300 PMCID: PMC10035319 DOI: 10.1128/cmr.00040-22] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Preventing and controlling influenza virus infection remains a global public health challenge, as it causes seasonal epidemics to unexpected pandemics. These infections are responsible for high morbidity, mortality, and substantial economic impact. Vaccines are the prophylaxis mainstay in the fight against influenza. However, vaccination fails to confer complete protection due to inadequate vaccination coverages, vaccine shortages, and mismatches with circulating strains. Antivirals represent an important prophylactic and therapeutic measure to reduce influenza-associated morbidity and mortality, particularly in high-risk populations. Here, we review current FDA-approved influenza antivirals with their mechanisms of action, and different viral- and host-directed influenza antiviral approaches, including immunomodulatory interventions in clinical development. Furthermore, we also illustrate the potential utility of machine learning in developing next-generation antivirals against influenza.
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Affiliation(s)
- Rashmi Kumari
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Suresh D. Sharma
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Amrita Kumar
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Zachary Ende
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Oak Ridge Institute for Science and Education (ORISE), CDC Fellowship Program, Oak Ridge, Tennessee, USA
| | - Margarita Mishina
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Yuanyuan Wang
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
- Association of Public Health Laboratories, Silver Spring, Maryland, USA
| | - Zackary Falls
- Department of Biomedical Informatics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Ram Samudrala
- Department of Biomedical Informatics, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Jan Pohl
- Biotechnology Core Facility Branch, Division of Scientific Resources, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Paul R. Knight
- Department of Anesthesiology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, USA
| | - Suryaprakash Sambhara
- Immunology and Pathogenesis Branch, Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Yang ML, Chen YC, Wang CT, Chong HE, Chung NH, Leu CH, Liu FT, Lai MMC, Ling P, Wu CL, Shiau AL. Upregulation of galectin-3 in influenza A virus infection promotes viral RNA synthesis through its association with viral PA protein. J Biomed Sci 2023; 30:14. [PMID: 36823664 PMCID: PMC9948428 DOI: 10.1186/s12929-023-00901-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/11/2023] [Indexed: 02/25/2023] Open
Abstract
BACKGROUND Influenza is one of the most important viral infections globally. Viral RNA-dependent RNA polymerase (RdRp) consists of the PA, PB1, and PB2 subunits, and the amino acid residues of each subunit are highly conserved among influenza A virus (IAV) strains. Due to the high mutation rate and emergence of drug resistance, new antiviral strategies are needed. Host cell factors are involved in the transcription and replication of influenza virus. Here, we investigated the role of galectin-3, a member of the β-galactoside-binding animal lectin family, in the life cycle of IAV infection in vitro and in mice. METHODS We used galectin-3 knockout and wild-type mice and cells to study the intracellular role of galectin-3 in influenza pathogenesis. Body weight and survival time of IAV-infected mice were analyzed, and viral production in mouse macrophages and lung fibroblasts was examined. Overexpression and knockdown of galectin-3 in A549 human lung epithelial cells were exploited to assess viral entry, viral ribonucleoprotein (vRNP) import/export, transcription, replication, virion production, as well as interactions between galectin-3 and viral proteins by immunoblotting, immunofluorescence, co-immunoprecipitation, RT-qPCR, minireplicon, and plaque assays. We also employed recombinant galectin-3 proteins to identify specific step(s) of the viral life cycle that was affected by exogenously added galectin-3 in A549 cells. RESULTS Galectin-3 levels were increased in the bronchoalveolar lavage fluid and lungs of IAV-infected mice. There was a positive correlation between galectin-3 levels and viral loads. Notably, galectin-3 knockout mice were resistant to IAV infection. Knockdown of galectin-3 significantly reduced the production of viral proteins and virions in A549 cells. While intracellular galectin-3 did not affect viral entry, it increased vRNP nuclear import, RdRp activity, and viral transcription and replication, which were associated with the interaction of galectin-3 with viral PA subunit. Galectin-3 enhanced the interaction between viral PA and PB1 proteins. Moreover, exogenously added recombinant galectin-3 proteins also enhanced viral adsorption and promoted IAV infection in A549 cells. CONCLUSION We demonstrate that galectin-3 enhances viral infection through increases in vRNP nuclear import and RdRp activity, thereby facilitating viral transcription and replication. Our findings also identify galectin-3 as a potential therapeutic target for influenza.
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Affiliation(s)
- Mei-Lin Yang
- grid.64523.360000 0004 0532 3255Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan ,grid.413878.10000 0004 0572 9327Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan
| | - Yi-Cheng Chen
- grid.64523.360000 0004 0532 3255Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan
| | - Chung-Teng Wang
- grid.64523.360000 0004 0532 3255Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan
| | - Hao-Earn Chong
- grid.64523.360000 0004 0532 3255Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan
| | - Nai-Hui Chung
- grid.64523.360000 0004 0532 3255Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan
| | - Chia-Hsing Leu
- grid.64523.360000 0004 0532 3255Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan
| | - Fu-Tong Liu
- grid.28665.3f0000 0001 2287 1366Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Michael M. C. Lai
- grid.254145.30000 0001 0083 6092Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan ,grid.28665.3f0000 0001 2287 1366Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Pin Ling
- grid.64523.360000 0004 0532 3255Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401 Taiwan
| | - Chao-Liang Wu
- Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan. .,Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401, Taiwan.
| | - Ai-Li Shiau
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, 1, University Road, Tainan, 701401, Taiwan. .,Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi, Taiwan.
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8
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Lou B, Liu Y, Shi M, Chen J, Li K, Tan Y, Chen L, Wu Y, Wang T, Liu X, Jiang T, Peng D, Liu Z. Aptamer-based biosensors for virus protein detection. Trends Analyt Chem 2022; 157:116738. [PMID: 35874498 PMCID: PMC9293409 DOI: 10.1016/j.trac.2022.116738] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/23/2022] [Accepted: 07/13/2022] [Indexed: 02/07/2023]
Abstract
Virus threatens life health seriously. The accurate early diagnosis of the virus is vital for clinical control and treatment of virus infection. Aptamers are small single-stranded oligonucleotides (DNAs or RNAs). In this review, we summarized aptasensors for virus detection in recent years according to the classification of the viral target protein, and illustrated common detection mechanisms in the aptasensors (colorimetry, fluorescence assay, surface plasmon resonance (SPR), surface-enhanced raman spectroscopy (SERS), electrochemical detection, and field-effect transistor (FET)). Furthermore, aptamers against different target proteins of viruses were summarized. The relationships between the different biomarkers of the viruses and the detection methods, and their performances were revealed. In addition, the challenges and future directions of aptasensors were discussed. This review will provide valuable references for constructing on-site aptasensors for detecting viruses, especially the SARS-CoV-2.
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Affiliation(s)
- Beibei Lou
- Department of Pharmaceutics, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, PR China
| | - Yanfei Liu
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan Province, PR China
| | - Meilin Shi
- School of Medical Imaging, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, PR China
| | - Jun Chen
- Department of Pharmaceutics, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, PR China
| | - Ke Li
- Department of Pharmaceutics, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, PR China
| | - Yifu Tan
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan Province, PR China
| | - Liwei Chen
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan Province, PR China
| | - Yuwei Wu
- Department of Pharmaceutics, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, PR China
| | - Ting Wang
- Department of Pharmaceutics, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, PR China
| | - Xiaoqin Liu
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan Province, PR China
| | - Ting Jiang
- Department of Pharmaceutical Engineering, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan Province, PR China
| | - Dongming Peng
- Department of Medicinal Chemistry, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, 410208, PR China
| | - Zhenbao Liu
- Department of Pharmaceutics, Xiangya School of Pharmaceutical Sciences, Central South University, Changsha, 410013, Hunan Province, PR China.,Molecular Imaging Research Center of Central South University, Changsha, 410008, Hunan, PR China
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Bioinformatics and Functional Analysis of a New Nuclear Localization Sequence of the Influenza A Virus Nucleoprotein. Cells 2022; 11:cells11192957. [PMID: 36230922 PMCID: PMC9563117 DOI: 10.3390/cells11192957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/30/2022] Open
Abstract
Influenza viruses deliver their genome into the nucleus of infected cells for replication. This process is mediated by the viral nucleoprotein (NP), which contains two nuclear localization sequences (NLSs): NLS1 at the N-terminus and a recently identified NLS2 (212GRKTR216). Through mutagenesis and functional studies, we demonstrated that NP must have both NLSs for an efficient nuclear import. As with other NLSs, there may be variations in the basic residues of NLS2 in different strains of the virus, which may affect the nuclear import of the viral genome. Although all NLS2 variants fused to the GFP mediated nuclear import of GFP, bioinformatics showed that 98.8% of reported NP sequences contained either the wild-type sequence 212GRKTR216 or 212GRRTR216. Bioinformatics analyses used to study the presence of NLS2 variants in other viral and nuclear proteins resulted in very low hits, with only 0.4% of human nuclear proteins containing putative NLS2. From these, we studied the nucleolar protein 14 (NOP14) and found that NLS2 does not play a role in the nuclear import of this protein but in its nucleolar localization. We also discovered a functional NLS at the C-terminus of NOP14. Our findings indicate that NLS2 is a highly conserved influenza A NP sequence.
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10
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Ling YH, Wang H, Han MQ, Wang D, Hu YX, Zhou K, Li Y. Nucleoporin 85 interacts with influenza A virus PB1 and PB2 to promote its replication by facilitating nuclear import of ribonucleoprotein. Front Microbiol 2022; 13:895779. [PMID: 36051755 PMCID: PMC9426659 DOI: 10.3389/fmicb.2022.895779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 07/29/2022] [Indexed: 11/30/2022] Open
Abstract
Transcription and replication of the influenza A virus (IAV) genome take place in the nucleus of infected cells, which rely on host factors to aid viral ribonucleoprotein (vRNP) to cross the nuclear pore complex (NPC) and complete the bidirectional nucleocytoplasmic trafficking. Here, we showed that nucleoporin 85 (NUP85), a component of NPC, interacted with RNP subunits polymerase basic 1 (PB1) and polymerase basic 2 (PB2) in an RNA-dependent manner during IAV infection. Knockdown of NUP85 delayed the nuclear import of vRNP, PB1 and PB2, inhibiting polymerase activity and ultimately suppressing viral replication. Further analysis revealed that NUP85 assisted the binding of PB1 to nuclear transport factor Ran-binding protein 5 (RanBP5) and the binding of PB2 to nuclear transport factor importin α1 and importin α7. We also found that NUP85 expression was downregulated upon IAV infection. Together, our study demonstrated that NUP85 positively regulated IAV infection by interacting with viral PB1 and PB2, which may provide new insight into the process of vRNP nuclear import and a novel target for effective antivirals.
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Affiliation(s)
- Yue-Huan Ling
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Hao Wang
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Mei-Qing Han
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Di Wang
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Yi-Xiang Hu
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
- Hainan Institute, Zhejiang University, Sanya, Hainan, China
| | - Kun Zhou
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
| | - Yan Li
- Department of Veterinary Medicine and Institute of Preventive Veterinary Sciences, Zhejiang University College of Animal Sciences, Hangzhou, Zhejiang, China
- Hainan Institute, Zhejiang University, Sanya, Hainan, China
- Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, Zhejiang, China
- *Correspondence: Yan Li,
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11
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Migration of Influenza Virus Nucleoprotein into the Nucleolus Is Essential for Ribonucleoprotein Complex Formation. mBio 2022. [PMCID: PMC8725578 DOI: 10.1128/mbio.03315-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Influenza A virus double-helical ribonucleoprotein complex (RNP) performs transcription and replication of viral genomic RNA (vRNA). Although RNP formation occurs in the nuclei of virus-infected cells, the nuclear domains involved in this process remain unclear. Here, we show that the nucleolus is an essential site for functional RNP formation. Viral nucleoprotein (NP), a major RNP component, temporarily localized to the nucleoli of virus-infected cells. Mutations in a nucleolar localization signal (NoLS) on NP abolished double-helical RNP formation, resulting in a loss of viral RNA synthesis ability, whereas ectopic fusion of the NoLS enabled the NP mutant to form functional double-helical RNPs. Furthermore, nucleolar disruption of virus-infected cells inhibited NP assembly into double-helical RNPs, resulting in decreased viral RNA synthesis. Collectively, our findings demonstrate that NP migration into the nucleolus is a critical step for functional RNP formation, showing the importance of the nucleolus in the influenza virus life cycle.
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12
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How Influenza A Virus NS1 Deals with the Ubiquitin System to Evade Innate Immunity. Viruses 2021; 13:v13112309. [PMID: 34835115 PMCID: PMC8619935 DOI: 10.3390/v13112309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/14/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022] Open
Abstract
Ubiquitination is a post-translational modification regulating critical cellular processes such as protein degradation, trafficking and signaling pathways, including activation of the innate immune response. Therefore, viruses, and particularly influenza A virus (IAV), have evolved different mechanisms to counteract this system to perform proper infection. Among IAV proteins, the non-structural protein NS1 is shown to be one of the main virulence factors involved in these viral hijackings. NS1 is notably able to inhibit the host's antiviral response through the perturbation of ubiquitination in different ways, as discussed in this review.
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13
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Shen Q, Wang YE, Palazzo AF. Crosstalk between nucleocytoplasmic trafficking and the innate immune response to viral infection. J Biol Chem 2021; 297:100856. [PMID: 34097873 PMCID: PMC8254040 DOI: 10.1016/j.jbc.2021.100856] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 12/16/2022] Open
Abstract
The nuclear pore complex is the sole gateway connecting the nucleoplasm and cytoplasm. In humans, the nuclear pore complex is one of the largest multiprotein assemblies in the cell, with a molecular mass of ∼110 MDa and consisting of 8 to 64 copies of about 34 different nuclear pore proteins, termed nucleoporins, for a total of 1000 subunits per pore. Trafficking events across the nuclear pore are mediated by nuclear transport receptors and are highly regulated. The nuclear pore complex is also used by several RNA viruses and almost all DNA viruses to access the host cell nucleoplasm for replication. Viruses hijack the nuclear pore complex, and nuclear transport receptors, to access the nucleoplasm where they replicate. In addition, the nuclear pore complex is used by the cell innate immune system, a network of signal transduction pathways that coordinates the first response to foreign invaders, including viruses and other pathogens. Several branches of this response depend on dynamic signaling events that involve the nuclear translocation of downstream signal transducers. Mounting evidence has shown that these signaling cascades, especially those steps that involve nucleocytoplasmic trafficking events, are targeted by viruses so that they can evade the innate immune system. This review summarizes how nuclear pore proteins and nuclear transport receptors contribute to the innate immune response and highlights how viruses manipulate this cellular machinery to favor infection. A comprehensive understanding of nuclear pore proteins in antiviral innate immunity will likely contribute to the development of new antiviral therapeutic strategies.
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Affiliation(s)
- Qingtang Shen
- School of Basic Medical Sciences, Fujian Medical University, Fuzhou, China.
| | - Yifan E Wang
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Alexander F Palazzo
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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14
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Malik G, Zhou Y. Innate Immune Sensing of Influenza A Virus. Viruses 2020; 12:E755. [PMID: 32674269 PMCID: PMC7411791 DOI: 10.3390/v12070755] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 12/18/2022] Open
Abstract
Influenza virus infection triggers host innate immune response by stimulating various pattern recognition receptors (PRRs). Activation of these PRRs leads to the activation of a plethora of signaling pathways, resulting in the production of interferon (IFN) and proinflammatory cytokines, followed by the expression of interferon-stimulated genes (ISGs), the recruitment of innate immune cells, or the activation of programmed cell death. All these antiviral approaches collectively restrict viral replication inside the host. However, influenza virus also engages in multiple mechanisms to subvert the innate immune responses. In this review, we discuss the role of PRRs such as Toll-like receptors (TLRs), Retinoic acid-inducible gene I (RIG-I), NOD-, LRR-, pyrin domain-containing protein 3 (NLRP3), and Z-DNA binding protein 1 (ZBP1) in sensing and restricting influenza viral infection. Further, we also discuss the mechanisms influenza virus utilizes, especially the role of viral non-structure proteins NS1, PB1-F2, and PA-X, to evade the host innate immune responses.
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Affiliation(s)
- Gaurav Malik
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, SK S7N 5E3, Canada;
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
| | - Yan Zhou
- Vaccine and Infectious Disease Organization-International Vaccine Centre (VIDO-InterVac), University of Saskatchewan, Saskatoon, SK S7N 5E3, Canada;
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
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15
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Abstract
Influenza A virus (IAV) is an enveloped virus of the Orthomyxoviridae with a negative-sense single-stranded RNA genome. During virus cell entry, viral and cellular cues are delivered in a stepwise manner within two distinct cellular compartments-the endosomes and the cytosol. Endosome maturation primes the viral core for uncoating by cytosolic host proteins and host-mediated virus disaggregation is essential for genome import and replication in the nucleus. Recent evidence shows that two well-known cellular proteins-histone deacetylase 6 (HDAC6) and karyopherin-β2 (kapβ2)-uncoat influenza virus. HDAC6 is 1 of 11 HDACs and an X-linked, cytosolic lysine deacetylase. Under normal cellular conditions HDAC6 is the tubulin deacetylase. Under proteasomal stress HDAC6 binds unanchored ubiquitin, dynein and myosin II to sequester misfolded protein aggregates for autophagy. Kapβ2 is a member of the importin β family that transports RNA-binding proteins into the nucleus by binding to disordered nuclear localization signals (NLSs) known as PY-NLS. Kapβ2 is emerging as a universal uncoating factor for IAV and human immunodeficiency virus type 1 (HIV-1). Kapβ2 can also reverse liquid-liquid phase separation (LLPS) of RNA-binding proteins by promoting their disaggregation. Thus, it is becoming evident that key players in the management of cellular condensates and membraneless organelles are potent virus uncoating factors. This emerging concept reveals implications in viral pathogenesis, as well as, the promise for cell-targeted therapeutic strategies to block universal virus uncoating pathways hijacked by enveloped RNA viruses.
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Affiliation(s)
- Yohei Yamauchi
- School of Cellular & Molecular Medicine, University of Bristol, Bristol, United Kingdom.
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16
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Microtubules in Influenza Virus Entry and Egress. Viruses 2020; 12:v12010117. [PMID: 31963544 PMCID: PMC7020094 DOI: 10.3390/v12010117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/14/2022] Open
Abstract
Influenza viruses are respiratory pathogens that represent a significant threat to public health, despite the large-scale implementation of vaccination programs. It is necessary to understand the detailed and complex interactions between influenza virus and its host cells in order to identify successful strategies for therapeutic intervention. During viral entry, the cellular microenvironment presents invading pathogens with a series of obstacles that must be overcome to infect permissive cells. Influenza hijacks numerous host cell proteins and associated biological pathways during its journey into the cell, responding to environmental cues in order to successfully replicate. The cellular cytoskeleton and its constituent microtubules represent a heavily exploited network during viral infection. Cytoskeletal filaments provide a dynamic scaffold for subcellular viral trafficking, as well as virus-host interactions with cellular machineries that are essential for efficient uncoating, replication, and egress. In addition, influenza virus infection results in structural changes in the microtubule network, which itself has consequences for viral replication. Microtubules, their functional roles in normal cell biology, and their exploitation by influenza viruses will be the focus of this review.
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17
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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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18
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Reina J, Zhou L, Fontes MRM, Panté N, Cella N. Identification of a putative nuclear localization signal in the tumor suppressor maspin sheds light on its nuclear import regulation. FEBS Open Bio 2019; 9:1174-1183. [PMID: 31144423 PMCID: PMC6609763 DOI: 10.1002/2211-5463.12626] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 02/27/2019] [Accepted: 03/18/2019] [Indexed: 12/12/2022] Open
Abstract
The tumor suppressor activity of maspin (mammary serine protease inhibitor) has been associated with its nuclear localization. In this study we explore the regulation of maspin nuclear translocation. An in vitro nuclear import assay suggested that maspin can passively enter the nucleus. However, in silico analysis identified a putative maspin nuclear localization signal (NLS), which was able to mediate the nuclear translocation of a chimeric protein containing this NLS fused to five green fluorescent protein molecules in tandem (5GFP). Dominant‐negative Ran‐GTPase mutants RanQ69L or RanT24N suppressed this process. Unexpectedly, the full‐length maspin fused to 5GFP failed to enter the nucleus. As maspin's putative NLS is partially hidden in its three‐dimensional structure, we suggest that maspin nuclear transport could be conformationally regulated. Our results suggest that maspin nuclear translocation involves both passive and active mechanisms.
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Affiliation(s)
- Jeffrey Reina
- Department of Cell and Developmental Biology, Institute of Biomedical Science of University of São Paulo, Brazil
| | - Lixin Zhou
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Marcos R M Fontes
- Department of Physics and Biophysics, Institute of Biosciences, São Paulo State University (UNESP), Botucatu, Brazil
| | - Nelly Panté
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - Nathalie Cella
- Department of Cell and Developmental Biology, Institute of Biomedical Science of University of São Paulo, Brazil
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19
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Resa-Infante P, Bonet J, Thiele S, Alawi M, Stanelle-Bertram S, Tuku B, Beck S, Oliva B, Gabriel G. Alternative interaction sites in the influenza A virus nucleoprotein mediate viral escape from the importin-α7 mediated nuclear import pathway. FEBS J 2019; 286:3374-3388. [PMID: 31044563 DOI: 10.1111/febs.14868] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 03/20/2019] [Accepted: 04/29/2019] [Indexed: 01/01/2023]
Abstract
Influenza A viruses are able to adapt to restrictive conditions due to their high mutation rates. Importin-α7 is a component of the nuclear import machinery required for avian-mammalian adaptation and replicative fitness in human cells. Here, we elucidate the mechanisms by which influenza A viruses may escape replicative restriction in the absence of importin-α7. To address this question, we assessed viral evolution in mice lacking the importin-α7 gene. We show that three mutations in particular occur with high frequency in the viral nucleoprotein (NP) protein (G102R, M105K and D375N) in a specific structural area upon in vivo adaptation. Moreover, our findings suggest that the adaptive NP mutations mediate viral escape from importin-α7 requirement likely due to the utilization of alternative interaction sites in NP beyond the classical nuclear localization signal. However, viral escape from importin-α7 by mutations in NP is, at least in part, associated with reduced viral replication highlighting the crucial contribution of importin-α7 to replicative fitness in human cells.
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Affiliation(s)
- Patricia Resa-Infante
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Jaume Bonet
- Structural Bioinformatics Lab (GRIB), Barcelona Research Park of Biomedicine (PRBB), Universitat Pompeu Fabra, Barcelona, Spain
| | - Swantje Thiele
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Malik Alawi
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.,Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Germany
| | | | - Berfin Tuku
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sebastian Beck
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Baldo Oliva
- Structural Bioinformatics Lab (GRIB), Barcelona Research Park of Biomedicine (PRBB), Universitat Pompeu Fabra, Barcelona, Spain
| | - Gülsah Gabriel
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany.,Institute of Virology, University of Veterinary Medicine Hannover, Hamburg, Germany
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20
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Nuñez IA, Ross TM. A review of H5Nx avian influenza viruses. Ther Adv Vaccines Immunother 2019; 7:2515135518821625. [PMID: 30834359 PMCID: PMC6391539 DOI: 10.1177/2515135518821625] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/09/2018] [Indexed: 12/12/2022] Open
Abstract
Highly pathogenic avian influenza viruses (HPAIVs), originating from the A/goose/Guangdong/1/1996 H5 subtype, naturally circulate in wild-bird populations, particularly waterfowl, and often spill over to infect domestic poultry. Occasionally, humans are infected with HPAVI H5N1 resulting in high mortality, but no sustained human-to-human transmission. In this review, the replication cycle, pathogenicity, evolution, spread, and transmission of HPAIVs of H5Nx subtypes, along with the host immune responses to Highly Pathogenic Avian Influenza Virus (HPAIV) infection and potential vaccination, are discussed. In addition, the potential mechanisms for Highly Pathogenic Avian Influenza Virus (HPAIV) H5 Reassorted Viruses H5N1, H5N2, H5N6, H5N8 (H5Nx) viruses to transmit, infect, and adapt to the human host are reviewed.
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Affiliation(s)
- Ivette A. Nuñez
- Center for Vaccines and Immunology, University of Georgia, Athens, Georgia, USA
| | - Ted M. Ross
- Center for Vaccines and Immunology, University of Georgia, 501 D.W. Brooks Drive, CVI Room 1504, Athens, GA 30602, USA
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21
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22
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The structure of the nucleoprotein of Influenza D shows that all Orthomyxoviridae nucleoproteins have a similar NP CORE, with or without a NP TAIL for nuclear transport. Sci Rep 2019; 9:600. [PMID: 30679709 PMCID: PMC6346101 DOI: 10.1038/s41598-018-37306-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
This paper focuses on the nucleoprotein (NP) of the newly identified member of the Orthomyxoviridae family, Influenza D virus. To date several X-ray structures of NP of Influenza A (A/NP) and B (B/NP) viruses and of infectious salmon anemia (ISA/NP) virus have been solved. Here we purified, characterized and solved the X-ray structure of the tetrameric D/NP at 2.4 Å resolution. The crystal structure of its core is similar to NP of other Influenza viruses. However, unlike A/NP and B/NP which possess a flexible amino-terminal tail containing nuclear localization signals (NLS) for their nuclear import, D/NP possesses a carboxy-terminal tail (D/NPTAIL). We show that D/NPTAIL harbors a bipartite NLS and designed C-terminal truncated mutants to demonstrate the role of D/NPTAIL for nuclear transport.
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23
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Influenza A Virus Utilizes Low-Affinity, High-Avidity Interactions with the Nuclear Import Machinery To Ensure Infection and Immune Evasion. J Virol 2018; 93:JVI.01046-18. [PMID: 30305352 DOI: 10.1128/jvi.01046-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/19/2018] [Indexed: 11/20/2022] Open
Abstract
The incoming influenza A virus (IAV) genome must pass through two distinct barriers in order to establish infection in the cell: the plasma membrane and the nuclear membrane. A precise understanding of the challenges imposed by the nuclear barrier remains outstanding. Passage across is mediated by host karyopherins (KPNAs), which bind to the viral nucleoprotein (NP) via its N-terminal nuclear localization sequence (NLS). The binding affinity between the two molecules is low, but NP is present in a high copy number, which suggests that binding avidity plays a compensatory role during import. Using nanobody-based technology, we demonstrate that a high binding avidity is required for infection, though the absolute value differs between cell types and correlates with their relative susceptibility to infection. In addition, we demonstrate that increasing the affinity level caused a decrease in avidity requirements for some cell types but blocked infection in others. Finally, we show that genomes that become frustrated by low avidity and remain cytoplasmic trigger the type I interferon response. Based on these results, we conclude that IAV balances affinity and avidity considerations in order to overcome the nuclear barrier across a broad range of cell types. Furthermore, these results provide evidence to support the long-standing hypothesis that IAV's strategy of import and replication in the nucleus facilitates immune evasion.IMPORTANCE We used intracellular nanobodies to block influenza virus infection at the step prior to nuclear import of its ribonucleoproteins. By doing so, we were able to answer an important but outstanding question that could not be addressed with conventional tools: how many of the ∼500 available NLS motifs are needed to establish infection? Furthermore, by controlling the subcellular localization of the incoming viral ribonucleoproteins and measuring the cell's antiviral response, we were able to provide direct evidence for the long-standing hypothesis that influenza virus exploits nuclear localization to delay activation of the innate immune response.
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24
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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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25
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Structural analysis of the complex between influenza B nucleoprotein and human importin-α. Sci Rep 2017; 7:17164. [PMID: 29215074 PMCID: PMC5719345 DOI: 10.1038/s41598-017-17458-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/27/2017] [Indexed: 12/29/2022] Open
Abstract
Influenza viruses are negative strand RNA viruses that replicate in the nucleus of the cell. The viral nucleoprotein (NP) is the major component of the viral ribonucleoprotein. In this paper we show that the NP of influenza B has a long N-terminal tail of 70 residues with intrinsic flexibility. This tail contains the Nuclear Location Signal (NLS). The nuclear trafficking of the viral components mobilizes cellular import factors at different stages, making these host-pathogen interactions promising targets for new therapeutics. NP is imported into the nucleus by the importin-α/β pathway, through a direct interaction with importin-α isoforms. Here we provide a combined nuclear magnetic resonance and small-angle X-ray scattering (NMR/SAXS) analysis to describe the dynamics of the interaction between influenza B NP and the human importin-α. The NP of influenza B does not have a single NLS nor a bipartite NLS but our results suggest that the tail harbors several adjacent NLS sequences, located between residues 30 and 71.
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26
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Nuclear transport of the Neurospora crassa NIT-2 transcription factor is mediated by importin-α. Biochem J 2017; 474:4091-4104. [DOI: 10.1042/bcj20170654] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Neurospora crassa NIT-2 transcription factor belongs to the GATA transcription factor family and plays a fundamental role in the regulation of nitrogen metabolism. Because NIT-2 acts by accessing DNA inside the nucleus, understanding the nuclear import process of NIT-2 is necessary to characterize its function. Thus, in the present study, NIT-2 nuclear transport was investigated using a combination of biochemical, cellular, and biophysical methods. A complemented strain that produced an sfGFP–NIT-2 fusion protein was constructed, and nuclear localization assessments were made under conditions that favored protein translocation to the nucleus. Nuclear translocation was also investigated using HeLa cells, which showed that the putative NIT-2 nuclear localization sequence (NLS; 915TISSKRQRRHSKS927) was recognized by importin-α and that subsequent transport occurred via the classical import pathway. The interaction between the N. crassa importin-α (NcImpα) and the NIT-2 NLS was quantified with calorimetric assays, leading to the observation that the peptide bound to two sites with different affinities, which is typical of a monopartite NLS sequence. The crystal structure of the NcImpα/NIT-2 NLS complex was solved and revealed that the NIT-2 peptide binds to NcImpα with the major NLS-binding site playing a primary role. This result contrasts other recent studies that suggested a major role for the minor NLS-binding site in importin-α from the α2 family, indicating that both sites can be used for different cargo proteins according to specific metabolic requirements.
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27
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Chu TL, Connell M, Zhou L, He Z, Won J, Chen H, Rahavi SM, Mohan P, Nemirovsky O, Fotovati A, Pujana MA, Reid GS, Nielsen TO, Pante N, Maxwell CA. Cell Cycle–Dependent Tumor Engraftment and Migration Are Enabled by Aurora-A. Mol Cancer Res 2017; 16:16-31. [DOI: 10.1158/1541-7786.mcr-17-0417] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/27/2017] [Accepted: 10/04/2017] [Indexed: 11/16/2022]
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28
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Wu W, Sankhala RS, Florio TJ, Zhou L, Nguyen NLT, Lokareddy RK, Cingolani G, Panté N. Synergy of two low-affinity NLSs determines the high avidity of influenza A virus nucleoprotein NP for human importin α isoforms. Sci Rep 2017; 7:11381. [PMID: 28900157 PMCID: PMC5595889 DOI: 10.1038/s41598-017-11018-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 08/17/2017] [Indexed: 11/26/2022] Open
Abstract
The influenza A virus nucleoprotein (NP) is an essential multifunctional protein that encapsidates the viral genome and functions as an adapter between the virus and the host cell machinery. NPs from all strains of influenza A viruses contain two nuclear localization signals (NLSs): a well-studied monopartite NLS1 and a less-characterized NLS2, thought to be bipartite. Through site-directed mutagenesis and functional analysis, we found that NLS2 is also monopartite and is indispensable for viral infection. Atomic structures of importin α bound to two variants of NLS2 revealed NLS2 primarily binds the major-NLS binding site of importin α, unlike NLS1 that associates with the minor NLS-pocket. Though peptides corresponding to NLS1 and NLS2 bind weakly to importin α, the two NLSs synergize in the context of the full length NP to confer high avidity for importin α7, explaining why the virus efficiently replicates in the respiratory tract that exhibits high levels of this isoform. This study, the first to functionally characterize NLS2, demonstrates NLS2 plays an important and unexpected role in influenza A virus infection. We propose NLS1 and NLS2 form a bipartite NLS in trans, which ensures high avidity for importin α7 while preventing non-specific binding to viral RNA.
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Affiliation(s)
- Wei Wu
- University of British Columbia, Department of Zoology, Vancouver, British Columbia, V6T1Z4, Canada
| | - Rajeshwer S Sankhala
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Tyler J Florio
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Lixin Zhou
- University of British Columbia, Department of Zoology, Vancouver, British Columbia, V6T1Z4, Canada
| | - Nhan L T Nguyen
- University of British Columbia, Department of Zoology, Vancouver, British Columbia, V6T1Z4, Canada
| | - Ravi K Lokareddy
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA
| | - Gino Cingolani
- Thomas Jefferson University, Department of Biochemistry and Molecular Biology, Philadelphia, PA, 19107, USA. .,Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, 70126, Bari, Italy.
| | - Nelly Panté
- University of British Columbia, Department of Zoology, Vancouver, British Columbia, V6T1Z4, Canada.
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29
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Dynamic regulation of T follicular regulatory cell responses by interleukin 2 during influenza infection. Nat Immunol 2017; 18:1249-1260. [PMID: 28892471 PMCID: PMC5679073 DOI: 10.1038/ni.3837] [Citation(s) in RCA: 168] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 08/18/2017] [Indexed: 12/31/2022]
Abstract
Interleukin 2 (IL-2) promotes Foxp3+ regulatory T (Treg) cell responses, but inhibits T follicular helper (TFH) cell development. However, it is not clear how IL-2 affects T follicular regulatory (TFR) cells, a cell type with properties of both Treg and TFH cells. Using an influenza infection model, we found that high IL-2 concentrations at the peak of the infection prevented TFR cell development by a Blimp-1-dependent mechanism. However, once the immune response resolved, some Treg cells downregulated CD25, upregulated Bcl-6 and differentiated into TFR cells, which then migrated into the B cell follicles to prevent the expansion of self-reactive B cell clones. Thus, unlike its effects on conventional Treg cells, IL-2 inhibits TFR cell responses.
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30
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Chen W, Xu Q, Zhong Y, Yu H, Shu J, Ma T, Li Z. Genetic variation and co-evolutionary relationship of RNA polymerase complex segments in influenza A viruses. Virology 2017; 511:193-206. [PMID: 28866238 DOI: 10.1016/j.virol.2017.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/18/2017] [Accepted: 07/20/2017] [Indexed: 11/19/2022]
Abstract
The RNA polymerase complex (RNApc) in influenza A viruses (IVs) is composed of the PB2, PB1 and PA subunits, which are encoded by the three longest genome segments (Seg1-3) and are responsible for the replication of vRNAs and transcription of viral mRNAs. However, the co-evolutionary relationships of the three segments from the known 126 subtypes IVs are unclear. In this study, we performed a detailed analysis based on a total number of 121,191 nucleotide sequences. Three segment sequences were aligned before the repeated, incomplete and mixed sequences were removed for homologous and phylogenetic analyses. Subsequently, the estimated substitution rates and TMRCAs (Times for Most Recent Common Ancestor) were calculated by 175 representative IVs. Tracing the cladistic distribution of three segments from these IVs, co-evolutionary patterns and trajectories could be inferred. The further correlation analysis of six internal protein coding segments reflect the RNApc segments have the closer correlation than others during continuous reassortments. This global approach facilitates the establishment of a fast antiviral strategy and monitoring of viral variation.
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Affiliation(s)
- Wentian Chen
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Qi Xu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Yaogang Zhong
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Hanjie Yu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Jian Shu
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Tianran Ma
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China
| | - Zheng Li
- Laboratory for Functional Glycomics, College of Life Sciences, Northwest University, Xi'an 710069, PR China.
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31
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Haralampiev I, Schade M, Chamiolo J, Jolmes F, Prisner S, Witkowski PT, Behrent M, Hövelmann F, Wolff T, Seitz O, Herrmann A. A Fluorescent RNA Forced-Intercalation Probe as a Pan-Selective Marker for Influenza A Virus Infection. Chembiochem 2017; 18:1589-1592. [PMID: 28557173 DOI: 10.1002/cbic.201700271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Indexed: 11/08/2022]
Abstract
The influenza A virus (IAV) genome is segmented into eight viral ribonucleoproteins, each expressing a negatively oriented viral RNA (vRNA). Along the infection cycle, highly abundant single-stranded small viral RNAs (svRNA) are transcribed in a segment-specific manner. The sequences of svRNAs and of the vRNA 5'-ends are identical and highly conserved among all IAV strains. Here, we demonstrate that these sequences can be used as a target for a pan-selective sensor of IAV infection. To this end, we used a complementary fluorescent forced-intercalation RNA (IAV QB-FIT) probe with a single locked nucleic acid substitution to increase brightness. We demonstrated by fluorescence in situ hybridization (FISH) that this probe is suitable and easy to use to detect infection of different cell types by a broad variety of avian, porcine, and human IAV strains, but not by other influenza virus types. IAV QB-FIT also provides a useful tool to characterize different infection states of the host cell.
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Affiliation(s)
- Ivan Haralampiev
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
| | - Matthias Schade
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
| | - Jasmine Chamiolo
- Institut für Chemie, Bioorganische Synthese, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Fabian Jolmes
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
| | - Simon Prisner
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
| | | | - Marie Behrent
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
| | - Felix Hövelmann
- Institut für Chemie, Bioorganische Synthese, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Thorsten Wolff
- Fachgebiet 17, Influenza und weitere Viren des Respirationstraktes, Seestrasse 10, 13353, Berlin, Germany
| | - Oliver Seitz
- Institut für Chemie, Bioorganische Synthese, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany
| | - Andreas Herrmann
- Institut für Biologie, Molekulare Biophysik, IRI Life Sciences, Humboldt-Universität zu Berlin, Invalidenstrasse 42, 10115, Berlin, Germany
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32
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Myaing MZ, Jumat MR, Huong TN, Tan BH, Sugrue RJ. Truncated forms of the PA protein containing only the C-terminal domains are associated with the ribonucleoprotein complex within H1N1 influenza virus particles. J Gen Virol 2017; 98:906-921. [PMID: 28141511 DOI: 10.1099/jgv.0.000721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We have examined the expression profile of the influenza virus PA protein in pH1N1/2009 virus-infected cells. Immunoblotting analysis of virus-infected MDCK cells revealed the presence of full-length PA protein from 8 h post-infection, together with the simultaneous appearance of PA protein species of approximately 50, 35/39 and 20/25 kDa (collectively referred to as PA*). PA* was also detected in H1N1/WSN-virus-infected cells, indicating that its presence was not virus-specific, and it was also observed in virus-infected A549 and chick embryo fibroblast (CEF) cells, indicating that its presence was not cell-type-specific. PA* was detected in cells expressing the recombinant PA protein, indicating that the PA* formation occurred in the absence of virus infection. These data collectively indicated that PA* formation is an intrinsic property of PA gene expression. The association of PA* with purified influenza virus particles was demonstrated by immunoblotting, and a protease protection assay provided evidence that PA* was packaged into virus particles. The ribonucleoprotein (RNP) complex was isolated from purified influenza virus particles using glycerol gradient centrifugation, which demonstrated that PA* was associated with the RNP complex. To the best of our knowledge, this is the first report to demonstrate that PA protein species containing only segments of the C-terminal domain form during influenza virus infection. Furthermore, these truncated PA protein species are subsequently packaged into virus particles as part of the functional RNP complex.
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Affiliation(s)
- Myint Zu Myaing
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Muhammad Raihan Jumat
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Tra Nguyen Huong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Boon Huan Tan
- Detection and Diagnostics Laboratory, DSO National Laboratories, 27 Medical Drive, Singapore 117510, Singapore
| | - Richard J Sugrue
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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33
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Höfer CT, Jolmes F, Haralampiev I, Veit M, Herrmann A. Influenza A virus nucleoprotein targets subnuclear structures. Cell Microbiol 2016; 19. [PMID: 27696627 DOI: 10.1111/cmi.12679] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 09/20/2016] [Accepted: 09/30/2016] [Indexed: 02/01/2023]
Abstract
The Influenza A virus nucleoprotein (NP) is the major protein component of the genomic viral ribonucleoprotein (vRNP) complexes, which are the replication- and transcription-competent units of Influenza viruses. Early during infection, NP mediates import of vRNPs into the host cell nucleus where viral replication and transcription take place; also newly synthesized NP molecules are targeted into the nucleus, enabling coreplicational assembly of progeny vRNPs. NP reportedly acts as regulatory factor during infection, and it is known to be involved in numerous interactions with host cell proteins. Yet, the NP-host cell interplay is still poorly understood. Here, we report that NP significantly interacts with the nuclear compartment and displays distinct affinities for different subnuclear structures. NP subnuclear behavior was studied by expression of fluorescent NP fusion proteins - including obligate monomeric NP - and site-specific fluorescence photoactivation measurements. We found that NP constructs accumulate in subnuclear domains frequently found adjacent to or overlapping with promyelocytic leukemia bodies and Cajal bodies. Targeting of NP to Cajal bodies could further be demonstrated in the context of virus infection. We hypothesize that by targeting functional nuclear organization, NP might either link viral replication to specific cellular machinery or interfere with host cell processes.
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Affiliation(s)
- Chris T Höfer
- IRI Life Sciences, Department of Biology, Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany.,Department of Veterinary Medicine, Institute of Virology, Freie Universität Berlin, Berlin, Germany
| | - Fabian Jolmes
- IRI Life Sciences, Department of Biology, Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ivan Haralampiev
- IRI Life Sciences, Department of Biology, Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Michael Veit
- Department of Veterinary Medicine, Institute of Virology, Freie Universität Berlin, Berlin, Germany
| | - Andreas Herrmann
- IRI Life Sciences, Department of Biology, Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
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34
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Schelker M, Mair CM, Jolmes F, Welke RW, Klipp E, Herrmann A, Flöttmann M, Sieben C. Viral RNA Degradation and Diffusion Act as a Bottleneck for the Influenza A Virus Infection Efficiency. PLoS Comput Biol 2016; 12:e1005075. [PMID: 27780209 PMCID: PMC5079570 DOI: 10.1371/journal.pcbi.1005075] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 07/24/2016] [Indexed: 12/21/2022] Open
Abstract
After endocytic uptake, influenza viruses transit early endosomal compartments and eventually reach late endosomes. There, the viral glycoprotein hemagglutinin (HA) triggers fusion between endosomal and viral membrane, a critical step that leads to release of the viral segmented genome destined to reach the cell nucleus. Endosomal maturation is a complex process involving acidification of the endosomal lumen as well as endosome motility along microtubules. While the pH drop is clearly critical for the conformational change and membrane fusion activity of HA, the effect of intracellular transport dynamics on the progress of infection remains largely unclear. In this study, we developed a comprehensive mathematical model accounting for the first steps of influenza virus infection. We calibrated our model with experimental data and challenged its predictions using recombinant viruses with altered pH sensitivity of HA. We identified the time point of virus-endosome fusion and thereby the diffusion distance of the released viral genome to the nucleus as a critical bottleneck for efficient virus infection. Further, we concluded and supported experimentally that the viral RNA is subjected to cytosolic degradation strongly limiting the probability of a successful genome import into the nucleus. Influenza A virus carries its segmented genome inside a lipid envelope. Since genome replication occurs inside the nucleus, the main goal of virus infection is to deliver all genome segments through the cytoplasm into the nucleus. After endocytic uptake, influenza viruses transit early endosomal compartments and eventually reach late endosomes. Within a complex maturation process, the endosomal lumen acidifies while the vesicles are transported trough the cytosol. If and how these early processes affect virus infection remained mostly speculative. To reach a better understanding and to quantify the physical interplay between membrane fusion, genome diffusion and infection, we developed a mathematical model that comprises all initial steps of virus infection until genome delivery. We calibrated our model using experimental data and challenged its predictions using recombinant viruses to introduce perturbations. Our results provide a theoretical framework to understand the importance of the endosomal virus passage before membrane fusion and genome release. We further unraveled RNA degradation as a previously unknown limiting factor for virus infection. Our work will help to make predictions and evaluate newly occurring virus strains, regarding their infection efficiency in a given host cell, by simply considering their pH sensitivity.
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Affiliation(s)
- Max Schelker
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Fabian Jolmes
- Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | | | - Edda Klipp
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Andreas Herrmann
- Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
- IRI Life Sciences, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Max Flöttmann
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
- * E-mail: (MF); (CS)
| | - Christian Sieben
- Molecular Biophysics, Humboldt-Universität zu Berlin, Berlin, Germany
- * E-mail: (MF); (CS)
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35
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Ubiquitin in Influenza Virus Entry and Innate Immunity. Viruses 2016; 8:v8100293. [PMID: 27783058 PMCID: PMC5086625 DOI: 10.3390/v8100293] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 10/14/2016] [Accepted: 10/14/2016] [Indexed: 12/20/2022] Open
Abstract
Viruses are obligatory cellular parasites. Their mission is to enter a host cell, to transfer the viral genome, and to replicate progeny whilst diverting cellular immunity. The role of ubiquitin is to regulate fundamental cellular processes such as endocytosis, protein degradation, and immune signaling. Many viruses including influenza A virus (IAV) usurp ubiquitination and ubiquitin-like modifications to establish infection. In this focused review, we discuss how ubiquitin and unanchored ubiquitin regulate IAV host cell entry, and how histone deacetylase 6 (HDAC6), a cytoplasmic deacetylase with ubiquitin-binding activity, mediates IAV capsid uncoating. We also discuss the roles of ubiquitin in innate immunity and its implications in the IAV life cycle.
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36
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Abstract
Influenza A viruses (IAVs) harbor a segmented RNA genome that is organized into eight distinct viral ribonucleoprotein (vRNP) complexes. Although a segmented genome may be a major advantage to adapt to new host environments, it comes at the cost of a highly sophisticated genome packaging mechanism. Newly synthesized vRNPs conquer the cellular endosomal recycling machinery to access the viral budding site at the plasma membrane. Genome packaging sequences unique to each RNA genome segment are thought to be key determinants ensuring the assembly and incorporation of eight distinct vRNPs into progeny viral particles. Recent studies using advanced fluorescence microscopy techniques suggest the formation of vRNP sub-bundles (comprising less than eight vRNPs) during their transport on recycling endosomes. The formation of such sub-bundles might be required for efficient packaging of a bundle of eight different genomes segments at the budding site, further highlighting the complexity of IAV genome packaging.
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37
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Yamauchi Y, Greber UF. Principles of Virus Uncoating: Cues and the Snooker Ball. Traffic 2016; 17:569-92. [PMID: 26875443 PMCID: PMC7169695 DOI: 10.1111/tra.12387] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/10/2016] [Accepted: 02/10/2016] [Indexed: 12/17/2022]
Abstract
Viruses are spherical or complex shaped carriers of proteins, nucleic acids and sometimes lipids and sugars. They are metastable and poised for structural changes. These features allow viruses to communicate with host cells during entry, and to release the viral genome, a process known as uncoating. Studies have shown that hundreds of host factors directly or indirectly support this process. The cell provides molecules that promote stepwise virus uncoating, and direct the virus to the site of replication. It acts akin to a snooker player who delivers accurate and timely shots (cues) to the ball (virus) to score. The viruses, on the other hand, trick (snooker) the host, hijack its homeostasis systems, and dampen innate immune responses directed against danger signals. In this review, we discuss how cellular cues, facilitators, and built‐in viral mechanisms promote uncoating. Cues come from receptors, enzymes and chemicals that act directly on the virus particle to alter its structure, trafficking and infectivity. Facilitators are defined as host factors that are involved in processes which indirectly enhance entry or uncoating. Unraveling the mechanisms of virus uncoating will continue to enhance understanding of cell functions, and help counteracting infections with chemicals and vaccines.
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Affiliation(s)
- Yohei Yamauchi
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Urs F Greber
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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38
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Götz V, Magar L, Dornfeld D, Giese S, Pohlmann A, Höper D, Kong BW, Jans DA, Beer M, Haller O, Schwemmle M. Influenza A viruses escape from MxA restriction at the expense of efficient nuclear vRNP import. Sci Rep 2016; 6:23138. [PMID: 26988202 PMCID: PMC4796820 DOI: 10.1038/srep23138] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 03/01/2016] [Indexed: 01/03/2023] Open
Abstract
To establish a new lineage in the human population, avian influenza A viruses (AIV) must overcome the intracellular restriction factor MxA. Partial escape from MxA restriction can be achieved when the viral nucleoprotein (NP) acquires the critical human-adaptive amino acid residues 100I/V, 283P, and 313Y. Here, we show that introduction of these three residues into the NP of an avian H5N1 virus renders it genetically unstable, resulting in viruses harboring additional single mutations, including G16D. These substitutions restored genetic stability yet again yielded viruses with varying degrees of attenuation in mammalian and avian cells. Additionally, most of the mutant viruses lost the capacity to escape MxA restriction, with the exception of the G16D virus. We show that MxA escape is linked to attenuation by demonstrating that the three substitutions promoting MxA escape disturbed intracellular trafficking of incoming viral ribonucleoprotein complexes (vRNPs), thereby resulting in impaired nuclear import, and that the additional acquired mutations only partially compensate for this import block. We conclude that for adaptation to the human host, AIV must not only overcome MxA restriction but also an associated block in nuclear vRNP import. This inherent difficulty may partially explain the frequent failure of AIV to become pandemic.
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Affiliation(s)
- Veronika Götz
- Institute of Virology, University Medical Center Freiburg, D-79104 Freiburg, Germany
| | - Linda Magar
- Institute of Virology, University Medical Center Freiburg, D-79104 Freiburg, Germany
| | - Dominik Dornfeld
- Institute of Virology, University Medical Center Freiburg, D-79104 Freiburg, Germany
| | - Sebastian Giese
- Institute of Virology, University Medical Center Freiburg, D-79104 Freiburg, Germany
| | - Anne Pohlmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, 17493 Greifswald-Insel Riems, Germany
| | - Dirk Höper
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, 17493 Greifswald-Insel Riems, Germany
| | - Byung-Whi Kong
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - David A Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, 17493 Greifswald-Insel Riems, Germany
| | - Otto Haller
- Institute of Virology, University Medical Center Freiburg, D-79104 Freiburg, Germany
| | - Martin Schwemmle
- Institute of Virology, University Medical Center Freiburg, D-79104 Freiburg, Germany
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39
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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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40
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Structure of importin-α bound to a non-classical nuclear localization signal of the influenza A virus nucleoprotein. Sci Rep 2015; 5:15055. [PMID: 26456934 PMCID: PMC4601014 DOI: 10.1038/srep15055] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/16/2015] [Indexed: 02/08/2023] Open
Abstract
A non-classical nuclear localization signal (ncNLS) of influenza A virus nucleoprotein (NP) is critical for nuclear import of viral genomic RNAs that transcribe and replicate in the nucleus of infected cells. Here we report a 2.3 Å resolution crystal structure of mouse importin-α1 in complex with NP ncNLS. The structure reveals that NP ncNLS binds specifically and exclusively to the minor NLS-binding site of importin-α. Structural and functional analyses identify key binding pockets on importin-α as potential targets for antiviral drug development. Unlike many other NLSs, NP ncNLS binds to the NLS-binding domain of importin-α weakly with micromolar affinity. These results suggest that a modest inhibitor with low affinity to importin-α could have anti-influenza activity with minimal cytotoxicity.
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41
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Caly L, Ghildyal R, Jans DA. Respiratory virus modulation of host nucleocytoplasmic transport; target for therapeutic intervention? Front Microbiol 2015; 6:848. [PMID: 26322040 PMCID: PMC4536372 DOI: 10.3389/fmicb.2015.00848] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/03/2015] [Indexed: 01/02/2023] Open
Abstract
The respiratory diseases caused by rhinovirus, respiratory syncytial virus, and influenza virus represent a large social and financial burden on healthcare worldwide. Although all three viruses have distinctly unique properties in terms of infection and replication, they share the ability to exploit/manipulate the host-cell nucleocytoplasmic transport system in order to replicate effectively and efficiently. This review outlines the various ways in which infection by these viruses impacts on the host nucleocytoplasmic transport system, and examples where inhibition thereof in turn decreases viral replication. The highly conserved nature of the nucleocytoplasmic transport system and the viral proteins that interact with it make this virus–host interface a prime candidate for the development of specific antiviral therapeutics in the future.
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Affiliation(s)
- Leon Caly
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC Australia
| | - Reena Ghildyal
- Faculty of ESTeM, University of Canberra, Bruce, ACT Australia
| | - David A Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC Australia
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42
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Hennig T, O'Hare P. Viruses and the nuclear envelope. Curr Opin Cell Biol 2015; 34:113-21. [PMID: 26121672 DOI: 10.1016/j.ceb.2015.06.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 10/23/2022]
Abstract
Viruses encounter and manipulate almost all aspects of cell structure and metabolism. The nuclear envelope (NE), with central roles in cell structure and genome function, acts and is usurped in diverse ways by different viruses. It can act as a physical barrier to infection that must be overcome, as a functional barrier that restricts infection by various mechanisms and must be counteracted or indeed as a positive niche, important or even essential for virus infection or production of progeny virions. This review summarizes virus-host interactions at the NE, highlighting progress in understanding the replication of viruses including HIV-1, Influenza, Herpes Simplex, Adenovirus and Ebola, and molecular insights into hitherto unknown functional pathways at the NE.
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Affiliation(s)
- Thomas Hennig
- Section of Virology, Faculty of Medicine, Imperial College, London W2 1PG, United Kingdom
| | - Peter O'Hare
- Section of Virology, Faculty of Medicine, Imperial College, London W2 1PG, United Kingdom.
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43
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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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44
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Intracellular expression of camelid single-domain antibodies specific for influenza virus nucleoprotein uncovers distinct features of its nuclear localization. J Virol 2014; 89:2792-800. [PMID: 25540369 DOI: 10.1128/jvi.02693-14] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Perturbation of protein-protein interactions relies mostly on genetic approaches or on chemical inhibition. Small RNA viruses, such as influenza A virus, do not easily lend themselves to the former approach, while chemical inhibition requires that the target protein be druggable. A lack of tools thus constrains the functional analysis of influenza virus-encoded proteins. We generated a panel of camelid-derived single-domain antibody fragments (VHHs) against influenza virus nucleoprotein (NP), a viral protein essential for nuclear trafficking and packaging of the influenza virus genome. We show that these VHHs can target NP in living cells and perturb NP's function during infection. Cytosolic expression of NP-specific VHHs (αNP-VHHs) disrupts virus replication at an early stage of the life cycle. Based on their specificity, these VHHs fall into two distinct groups. Both prevent nuclear import of the viral ribonucleoprotein (vRNP) complex without disrupting nuclear import of NP alone. Different stages of the virus life cycle thus rely on distinct nuclear localization motifs of NP. Their molecular characterization may afford new means of intervention in the virus life cycle. IMPORTANCE Many proteins encoded by RNA viruses are refractory to manipulation due to their essential role in replication. Thus, studying their function and determining how to disrupt said function through pharmaceutical intervention are difficult. We present a novel method based on single-domain-antibody technology that permits specific targeting and disruption of an essential influenza virus protein in the absence of genetic manipulation of influenza virus itself. Characterization of such interactions may help identify new targets for pharmaceutical intervention. This approach can be extended to study proteins encoded by other viral pathogens.
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The N terminus of the influenza B virus nucleoprotein is essential for virus viability, nuclear localization, and optimal transcription and replication of the viral genome. J Virol 2014; 88:12326-38. [PMID: 25122787 DOI: 10.1128/jvi.01542-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
UNLABELLED The nucleoprotein (NP) of influenza viruses is a multifunctional protein with essential roles throughout viral replication. Despite influenza A and B viruses belonging to separate genera of the Orthomyxoviridae family, their NP proteins share a relatively high level of sequence conservation. However, NP of influenza B viruses (BNP) contains an evolutionarily conserved N-terminal 50-amino-acid extension that is absent from NP of influenza A viruses. There is conflicting evidence as to the functions of the BNP N-terminal extension; however, this has never been assessed in the context of viral infection. We have used reverse genetics to assess the significance of this region on the functions of BNP and virus viability. The truncation of more than three amino acids prevented virus recovery, suggesting that the N-terminal extension is essential for virus viability. Mutational analysis indicated that multiple regions of the protein are involved in the nuclear localization of BNP, with the entire N-terminal extension required for this to function efficiently. Viruses containing mutations in the first 10 residues of BNP demonstrated few differences in nuclear localization; however, the viruses exhibited significant reductions in viral mRNA transcription and genome replication, resulting in significantly attenuated phenotypes. Mutations introduced to ablate a previously reported nuclear localization signal also resulted in a significant decrease in mRNA production during early stages of viral replication. Overall, our results demonstrate that the N-terminal extension of BNP is essential to virus viability not only for directing nuclear localization of BNP but also for regulating viral mRNA transcription and genome replication. IMPORTANCE The multifunctional NP of influenza viruses has roles throughout the viral replication cycle; therefore, it is essential for virus viability. Despite high levels of homology between the NP of influenza A and B viruses, the NP of influenza B virus contains an evolutionarily conserved 50-amino-acid N-terminal extension that is absent from the NP of influenza A viruses. In this study, we show that this N-terminal extension is essential for virus viability, and we confirm and expand upon recent findings that this region of BNP is required for nuclear localization of the protein. Furthermore, we demonstrate for the first time that the N terminus of BNP is involved in regulating viral mRNA transcription and replication of the viral genome. As the NP of influenza A virus lacks this N-terminal extension, these viruses may have evolved separate mechanisms to regulate these processes.
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Brunotte L, Flies J, Bolte H, Reuther P, Vreede F, Schwemmle M. The nuclear export protein of H5N1 influenza A viruses recruits Matrix 1 (M1) protein to the viral ribonucleoprotein to mediate nuclear export. J Biol Chem 2014; 289:20067-77. [PMID: 24891509 DOI: 10.1074/jbc.m114.569178] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In influenza A virus-infected cells, replication and transcription of the viral genome occurs in the nucleus. To be packaged into viral particles at the plasma membrane, encapsidated viral genomes must be exported from the nucleus. Intriguingly, the nuclear export protein (NEP) is involved in both processes. Although NEP stimulates viral RNA synthesis by binding to the viral polymerase, its function during nuclear export implicates interaction with viral ribonucleoprotein (vRNP)-associated M1. The observation that both interactions are mediated by the C-terminal moiety of NEP raised the question whether these two features of NEP are linked functionally. Here we provide evidence that the interaction between M1 and the vRNP depends on the NEP C terminus and its polymerase activity-enhancing property for the nuclear export of vRNPs. This suggests that these features of NEP are linked functionally. Furthermore, our data suggest that the N-terminal domain of NEP interferes with the stability of the vRNP-M1-NEP nuclear export complex, probably mediated by its highly flexible intramolecular interaction with the NEP C terminus. On the basis of our data, we propose a new model for the assembly of the nuclear export complex of Influenza A vRNPs.
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Affiliation(s)
- Linda Brunotte
- From the Institute for Virology, University Medical Center Freiburg, Hermann-Herder-Str. 11, 79104 Freiburg, Germany and
| | - Joe Flies
- From the Institute for Virology, University Medical Center Freiburg, Hermann-Herder-Str. 11, 79104 Freiburg, Germany and
| | - Hardin Bolte
- From the Institute for Virology, University Medical Center Freiburg, Hermann-Herder-Str. 11, 79104 Freiburg, Germany and
| | - Peter Reuther
- From the Institute for Virology, University Medical Center Freiburg, Hermann-Herder-Str. 11, 79104 Freiburg, Germany and
| | - Frank Vreede
- the Sir William Dunn School of Pathology, University of Oxford, South Parks Rd., Oxford OX 3RE, United Kingdom
| | - Martin Schwemmle
- From the Institute for Virology, University Medical Center Freiburg, Hermann-Herder-Str. 11, 79104 Freiburg, Germany and
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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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Matsuoka Y, Matsumae H, Katoh M, Eisfeld AJ, Neumann G, Hase T, Ghosh S, Shoemaker JE, Lopes TJS, Watanabe T, Watanabe S, Fukuyama S, Kitano H, Kawaoka Y. A comprehensive map of the influenza A virus replication cycle. BMC SYSTEMS BIOLOGY 2013; 7:97. [PMID: 24088197 PMCID: PMC3819658 DOI: 10.1186/1752-0509-7-97] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/24/2013] [Indexed: 02/05/2023]
Abstract
Background Influenza is a common infectious disease caused by influenza viruses. Annual epidemics cause severe illnesses, deaths, and economic loss around the world. To better defend against influenza viral infection, it is essential to understand its mechanisms and associated host responses. Many studies have been conducted to elucidate these mechanisms, however, the overall picture remains incompletely understood. A systematic understanding of influenza viral infection in host cells is needed to facilitate the identification of influential host response mechanisms and potential drug targets. Description We constructed a comprehensive map of the influenza A virus (‘IAV’) life cycle (‘FluMap’) by undertaking a literature-based, manual curation approach. Based on information obtained from publicly available pathway databases, updated with literature-based information and input from expert virologists and immunologists, FluMap is currently composed of 960 factors (i.e., proteins, mRNAs etc.) and 456 reactions, and is annotated with ~500 papers and curation comments. In addition to detailing the type of molecular interactions, isolate/strain specific data are also available. The FluMap was built with the pathway editor CellDesigner in standard SBML (Systems Biology Markup Language) format and visualized as an SBGN (Systems Biology Graphical Notation) diagram. It is also available as a web service (online map) based on the iPathways+ system to enable community discussion by influenza researchers. We also demonstrate computational network analyses to identify targets using the FluMap. Conclusion The FluMap is a comprehensive pathway map that can serve as a graphically presented knowledge-base and as a platform to analyze functional interactions between IAV and host factors. Publicly available webtools will allow continuous updating to ensure the most reliable representation of the host-virus interaction network. The FluMap is available at http://www.influenza-x.org/flumap/.
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Affiliation(s)
- Yukiko Matsuoka
- JST ERATO Kawaoka infection-induced host responses project, Minato-ku, Tokyo 108-8639, Japan.
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Wanitchang A, Narkpuk J, Jongkaewwattana A. Nuclear import of influenza B virus nucleoprotein: Involvement of an N-terminal nuclear localization signal and a cleavage-protection motif. Virology 2013; 443:59-68. [DOI: 10.1016/j.virol.2013.04.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/05/2013] [Accepted: 04/25/2013] [Indexed: 10/26/2022]
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50
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Zhang H, Hale BG, Xu K, Sun B. Viral and host factors required for avian H5N1 influenza A virus replication in mammalian cells. Viruses 2013; 5:1431-46. [PMID: 23752648 PMCID: PMC3717715 DOI: 10.3390/v5061431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 02/07/2013] [Accepted: 05/23/2013] [Indexed: 12/18/2022] Open
Abstract
Following the initial and sporadic emergence into humans of highly pathogenic avian H5N1 influenza A viruses in Hong Kong in 1997, we have come to realize the potential for avian influenza A viruses to be transmitted directly from birds to humans. Understanding the basic viral and cellular mechanisms that contribute to infection of mammalian species with avian influenza viruses is essential for developing prevention and control measures against possible future human pandemics. Multiple physical and functional cellular barriers can restrict influenza A virus infection in a new host species, including the cell membrane, the nuclear envelope, the nuclear environment, and innate antiviral responses. In this review, we summarize current knowledge on viral and host factors required for avian H5N1 influenza A viruses to successfully establish infections in mammalian cells. We focus on the molecular mechanisms underpinning mammalian host restrictions, as well as the adaptive mutations that are necessary for an avian influenza virus to overcome them. It is likely that many more viral and host determinants remain to be discovered, and future research in this area should provide novel and translational insights into the biology of influenza virus-host interactions.
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Affiliation(s)
- Hong Zhang
- Molecular Virus Unit, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai institutes for Biological Sciences, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China; E-Mail:
| | - Benjamin G. Hale
- Medical Research Council (MRC), University of Glasgow Centre for Virus Research, 8 Church Street, Glasgow, G11 5JR, Scotland, UK; E-Mail:
| | - Ke Xu
- Molecular Virus Unit, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai institutes for Biological Sciences, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (K.X.); (B.S.); Tel.: +86-21-6385-1929 (K.X.); +86-21-6385-1927 (B.S.); Fax: +86-21-6384-3571 (K.X. and B.S.)
| | - Bing Sun
- Molecular Virus Unit, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai institutes for Biological Sciences, Chinese Academy of Sciences, 225 South Chongqing Road, Shanghai 200025, China; E-Mail:
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
- Authors to whom correspondence should be addressed; E-Mails: (K.X.); (B.S.); Tel.: +86-21-6385-1929 (K.X.); +86-21-6385-1927 (B.S.); Fax: +86-21-6384-3571 (K.X. and B.S.)
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