1
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Kumar A, Kaushal R, Sharma H, Sharma K, Menon MB, P V. Mapping of long stretches of highly conserved sequences in over 6 million SARS-CoV-2 genomes. Brief Funct Genomics 2024; 23:256-264. [PMID: 37461194 DOI: 10.1093/bfgp/elad027] [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: 01/27/2023] [Revised: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 05/18/2024] Open
Abstract
We identified 11 conserved stretches in over 6.3 million SARS-CoV-2 genomes including all the major variants of concerns. Each conserved stretch is ≥100 nucleotides in length with ≥99.9% conservation at each nucleotide position. Interestingly, six of the eight conserved stretches in ORF1ab overlapped significantly with well-folded experimentally verified RNA secondary structures. Furthermore, two of the conserved stretches were mapped to regions within the S2-subunit that undergo dynamic structural rearrangements during viral fusion. In addition, the conserved stretches were significantly depleted for zinc-finger antiviral protein (ZAP) binding sites, which facilitated the recognition and degradation of viral RNA. These highly conserved stretches in the SARS-CoV-2 genome were poorly conserved at the nucleotide level among closely related β-coronaviruses, thus representing ideal targets for highly specific and discriminatory diagnostic assays. Our findings highlight the role of structural constraints at both RNA and protein levels that contribute to the sequence conservation of specific genomic regions in SARS-CoV-2.
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Affiliation(s)
- Akhil Kumar
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Rishika Kaushal
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Himanshi Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Khushboo Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Manoj B Menon
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Vivekanandan P
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
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2
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Ciminski K, Flore V, Jakob C, Mues H, Smedegaard Frederiksen A, Schwemmle M, Bolte H, Giese S. Functionality of IAV packaging signals depends on site-specific charges within the viral nucleoprotein. J Virol 2024; 98:e0197223. [PMID: 38470155 PMCID: PMC11019843 DOI: 10.1128/jvi.01972-23] [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] [Received: 12/15/2023] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
The coordinated packaging of the segmented genome of the influenza A virus (IAV) into virions is an essential step of the viral life cycle. This process is controlled by the interaction of packaging signals present in all eight viral RNA (vRNA) segments and the viral nucleoprotein (NP), which binds vRNA via a positively charged binding groove. However, mechanistic models of how the packaging signals and NP work together to coordinate genome packaging are missing. Here, we studied genome packaging in influenza A/SC35M virus mutants that carry mutated packaging signals as well as specific amino acid substitutions at the highly conserved lysine (K) residues 184 and 229 in the RNA-binding groove of NP. Because these lysines are acetylated and thus neutrally charged in infected host cells, we replaced them with glutamine to mimic the acetylated, neutrally charged state or arginine to mimic the non-acetylated, positively charged state. Our analysis shows that the coordinated packaging of eight vRNAs is influenced by (i) the charge state of the replacing amino acid and (ii) its location within the RNA-binding groove. Accordingly, we propose that lysine acetylation induces different charge states within the RNA-binding groove of NP, thereby supporting the activity of specific packaging signals during coordinated genome packaging. IMPORTANCE Influenza A viruses (IAVs) have a segmented viral RNA (vRNA) genome encapsidated by multiple copies of the viral nucleoprotein (NP) and organized into eight distinct viral ribonucleoprotein complexes. Although genome segmentation contributes significantly to viral evolution and adaptation, it requires a highly sophisticated genome-packaging mechanism. How eight distinct genome complexes are incorporated into the virion is poorly understood, but previous research suggests an essential role for both vRNA packaging signals and highly conserved NP amino acids. By demonstrating that the packaging process is controlled by charge-dependent interactions of highly conserved lysine residues in NP and vRNA packaging signals, our study provides new insights into the sophisticated packaging mechanism of IAVs.
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Affiliation(s)
- Kevin Ciminski
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Viktoria Flore
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Celia Jakob
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Helen Mues
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anne Smedegaard Frederiksen
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Martin Schwemmle
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hardin Bolte
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Sebastian Giese
- Institute of Virology, Freiburg University Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
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3
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Beniston E, Skittrall JP. Locations and structures of influenza A virus packaging-associated signals and other functional elements via an in silico pipeline for predicting constrained features in RNA viruses. PLoS Comput Biol 2024; 20:e1012009. [PMID: 38648223 PMCID: PMC11034665 DOI: 10.1371/journal.pcbi.1012009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Influenza A virus contains regions of its segmented genome associated with ability to package the segments into virions, but many such regions are poorly characterised. We provide detailed predictions of the key locations within these packaging-associated regions, and their structures, by applying a recently-improved pipeline for delineating constrained regions in RNA viruses and applying structural prediction algorithms. We find and characterise other known constrained regions within influenza A genomes, including the region associated with the PA-X frameshift, regions associated with alternative splicing, and constraint around the initiation motif for a truncated PB1 protein, PB1-N92, associated with avian viruses. We further predict the presence of constrained regions that have not previously been described. The extra characterisation our work provides allows investigation of these key regions for drug target potential, and points towards determinants of packaging compatibility between segments.
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Affiliation(s)
- Emma Beniston
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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4
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Girard J, Jakob C, Toews LK, Fuchs J, Pohlmann A, Franzke K, Kolesnikova L, Jeney C, Beer M, Bron P, Schwemmle M, Bolte H. Disruption of influenza virus packaging signals results in various misassembled genome complexes. J Virol 2023; 97:e0107623. [PMID: 37811996 PMCID: PMC10617545 DOI: 10.1128/jvi.01076-23] [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] [Received: 07/17/2023] [Accepted: 08/25/2023] [Indexed: 10/10/2023] Open
Abstract
IMPORTANCE The influenza A virus genome consists of eight distinct viral RNAs (vRNAs) that are typically packaged into a single virion as an octameric complex. How this genome complex is assembled and incorporated into the virion is poorly understood, but previous research suggests a coordinative role for packaging signals present in all vRNAs. Here, we show that disruption of two packaging signals in a model H7N7 influenza A virus results in a mixture of virions with unusual vRNA content, including empty virions, virions with one to four vRNAs, and virions with octameric complexes composed of vRNA duplicates. Our results suggest that (i) the assembly of error-free octameric complexes proceeds through a series of defined vRNA sub-complexes and (ii) virions can bud without incorporating complete octameric complexes.
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Affiliation(s)
- Justine Girard
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Celia Jakob
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Lina Kathrin Toews
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Jonas Fuchs
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anne Pohlmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Kati Franzke
- Institute of Infectology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | | | | | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald, Germany
| | - Patrick Bron
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Martin Schwemmle
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hardin Bolte
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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5
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Jakob C, Lovate GL, Desirò D, Gießler L, Smyth R, Marquet R, Lamkiewicz K, Marz M, Schwemmle M, Bolte H. Sequential disruption of SPLASH-identified vRNA-vRNA interactions challenges their role in influenza A virus genome packaging. Nucleic Acids Res 2023; 51:6479-6494. [PMID: 37224537 PMCID: PMC10325904 DOI: 10.1093/nar/gkad442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/02/2023] [Accepted: 05/10/2023] [Indexed: 05/26/2023] Open
Abstract
A fundamental step in the influenza A virus (IAV) replication cycle is the coordinated packaging of eight distinct genomic RNA segments (i.e. vRNAs) into a viral particle. Although this process is thought to be controlled by specific vRNA-vRNA interactions between the genome segments, few functional interactions have been validated. Recently, a large number of potentially functional vRNA-vRNA interactions have been detected in purified virions using the RNA interactome capture method SPLASH. However, their functional significance in coordinated genome packaging remains largely unclear. Here, we show by systematic mutational analysis that mutant A/SC35M (H7N7) viruses lacking several prominent SPLASH-identified vRNA-vRNA interactions involving the HA segment package the eight genome segments as efficiently as the wild-type virus. We therefore propose that the vRNA-vRNA interactions identified by SPLASH in IAV particles are not necessarily critical for the genome packaging process, leaving the underlying molecular mechanism elusive.
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Affiliation(s)
- Celia Jakob
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Gabriel L Lovate
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Germany
| | - Daniel Desirò
- Department of Biochemistry, University of Cambridge, CambridgeCB2 1QW, UK
| | - Lara Gießler
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
| | - Redmond P Smyth
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg, Germany
- Julius-Maximilians-Universität Würzburg, Faculty of Medicine, Würzburg, Germany
| | - Roland Marquet
- Architecture et Réactivité de l’ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg, France
| | - Kevin Lamkiewicz
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Germany
- German Center for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
| | - Manja Marz
- RNA Bioinformatics and High-Throughput Analysis, Faculty of Mathematics and Computer Science, Friedrich Schiller University Jena, Germany
- German Center for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
- European Virus Bioinformatics Center (EVBC), Jena, Germany
- FLI Leibniz Institute for Age Research, Jena, Germany
| | - Martin Schwemmle
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Hardin Bolte
- Institute of Virology, Medical Center – University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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6
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Mirska B, Woźniak T, Lorent D, Ruszkowska A, Peterson JM, Moss WN, Mathews DH, Kierzek R, Kierzek E. In vivo secondary structural analysis of Influenza A virus genomic RNA. Cell Mol Life Sci 2023; 80:136. [PMID: 37131079 PMCID: PMC10153785 DOI: 10.1007/s00018-023-04764-1] [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: 10/28/2022] [Revised: 03/19/2023] [Accepted: 03/19/2023] [Indexed: 05/04/2023]
Abstract
Influenza A virus (IAV) is a respiratory virus that causes epidemics and pandemics. Knowledge of IAV RNA secondary structure in vivo is crucial for a better understanding of virus biology. Moreover, it is a fundament for the development of new RNA-targeting antivirals. Chemical RNA mapping using selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) coupled with Mutational Profiling (MaP) allows for the thorough examination of secondary structures in low-abundance RNAs in their biological context. So far, the method has been used for analyzing the RNA secondary structures of several viruses including SARS-CoV-2 in virio and in cellulo. Here, we used SHAPE-MaP and dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq) for genome-wide secondary structure analysis of viral RNA (vRNA) of the pandemic influenza A/California/04/2009 (H1N1) strain in both in virio and in cellulo environments. Experimental data allowed the prediction of the secondary structures of all eight vRNA segments in virio and, for the first time, the structures of vRNA5, 7, and 8 in cellulo. We conducted a comprehensive structural analysis of the proposed vRNA structures to reveal the motifs predicted with the highest accuracy. We also performed a base-pairs conservation analysis of the predicted vRNA structures and revealed many highly conserved vRNA motifs among the IAVs. The structural motifs presented herein are potential candidates for new IAV antiviral strategies.
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Affiliation(s)
- Barbara Mirska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Tomasz Woźniak
- Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska 32, 60-479, Poznan, Poland
| | - Dagny Lorent
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Agnieszka Ruszkowska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Jake M Peterson
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - Walter N Moss
- Roy J. Carver Department of Biophysics, Biochemistry and Molecular Biology, Iowa State University, Ames, IA, 50011, USA
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 712, Rochester, NY, 14642, USA
| | - Ryszard Kierzek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Elzbieta Kierzek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland.
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7
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Dong J, Dong Z, Feng P, Gao Y, Li J, Wang Y, Han L, Li Z, Wang Q, Niu X, Li C, Pan W, Chen L. Influenza Virus Carrying a Codon-Reprogrammed Neuraminidase Gene as a Strategy for Live Attenuated Vaccine. Vaccines (Basel) 2023; 11:vaccines11020391. [PMID: 36851268 PMCID: PMC9959331 DOI: 10.3390/vaccines11020391] [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: 12/27/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
Live attenuated influenza vaccines offer broader and longer-lasting protection in comparison to inactivated influenza vaccines. The neuraminidase (NA) surface glycoprotein of influenza A virus is essential for the release and spread of progeny viral particles from infected cells. In this study, we de novo synthesized the NA gene, in which 62% of codons were synonymously changed based on mammalian codon bias usage. The codon-reprogrammed NA (repNA) gene failed to be packaged into the viral genome, which was achievable with partial restoration of wild-type NA sequence nucleotides at the 3' and 5' termini. Among a series of rescued recombinant viruses, we selected 20/13repNA, which contained 20 and 13 nucleotides of wild-type NA at the 3' and 5' termini of repNA, respectively, and evaluated its potential as a live attenuated influenza vaccine. The 20/13repNA is highly attenuated in mice, and the calculated LD50 was about 10,000-fold higher than that of the wild-type (WT) virus. Intranasal inoculation of the 20/13repNA virus in mice induced viral-specific humoral, cell-mediated, and mucosal immune responses. Mice vaccinated with the 20/13repNA virus were protected from the lethal challenge of both homologous and heterologous viruses. This strategy may provide a new method for the development of live, attenuated influenza vaccines for a better and more rapid response to influenza threats.
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Affiliation(s)
- Ji Dong
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Zhenyuan Dong
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510535, China
| | - Pei Feng
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Yu Gao
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Jiashun Li
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Yang Wang
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Lujie Han
- Guangzhou nBiomed Ltd., Guangzhou 510535, China
| | - Zhixia Li
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510535, China
| | - Qian Wang
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Xuefeng Niu
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Chufang Li
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
| | - Weiqi Pan
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
- Correspondence: (W.P.); (L.C.)
| | - Ling Chen
- State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510182, China
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510535, China
- Guangzhou nBiomed Ltd., Guangzhou 510535, China
- Correspondence: (W.P.); (L.C.)
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8
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Adaptive evolution of PB1 from influenza A(H1N1)pdm09 virus towards an enhanced fitness. Virology 2023; 578:1-6. [PMID: 36423573 DOI: 10.1016/j.virol.2022.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/18/2022]
Abstract
PB1 influenza virus retain traces of interspecies transmission and adaptation. Previous phylogenetic analyses highlighted mutations L298I, R386K and I517V in PB1 to have putatively ameliorated the A(H1N1)pdm09 adaptation to the human host. This study aimed to evaluate the reversal of these mutations and infer the role of these residues in the virus overall fitness and adaptation. We generate PB1-mutated viruses introducing I298L, K386R and V517I mutations in PB1 and evaluate their phenotypic impact on viral growth and on antigen yield. We observed a decrease in viral growth accompanied by a reduction in hemagglutination titer and neuraminidase activity, in comparison with wt. Our data indicate that the adaptive evolution occurred in the PB1 leads to an improved overall viral fitness; and such biologic advantaged has the potential to be applied to the optimization of influenza vaccine seed prototypes.
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9
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Jakob C, Paul-Stansilaus R, Schwemmle M, Marquet R, Bolte H. The influenza A virus genome packaging network - complex, flexible and yet unsolved. Nucleic Acids Res 2022; 50:9023-9038. [PMID: 35993811 PMCID: PMC9458418 DOI: 10.1093/nar/gkac688] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/19/2022] [Accepted: 08/18/2022] [Indexed: 12/24/2022] Open
Abstract
The genome of influenza A virus (IAV) consists of eight unique viral RNA segments. This genome organization allows genetic reassortment between co-infecting IAV strains, whereby new IAVs with altered genome segment compositions emerge. While it is known that reassortment events can create pandemic IAVs, it remains impossible to anticipate reassortment outcomes with pandemic prospects. Recent research indicates that reassortment is promoted by a viral genome packaging mechanism that delivers the eight genome segments as a supramolecular complex into the virus particle. This finding holds promise of predicting pandemic IAVs by understanding the intermolecular interactions governing this genome packaging mechanism. Here, we critically review the prevailing mechanistic model postulating that IAV genome packaging is orchestrated by a network of intersegmental RNA-RNA interactions. Although we find supporting evidence, including segment-specific packaging signals and experimentally proposed RNA-RNA interaction networks, this mechanistic model remains debatable due to a current shortage of functionally validated intersegmental RNA-RNA interactions. We speculate that identifying such functional intersegmental RNA-RNA contacts might be hampered by limitations of the utilized probing techniques and the inherent complexity of the genome packaging mechanism. Nevertheless, we anticipate that improved probing strategies combined with a mutagenesis-based validation could facilitate their discovery.
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Affiliation(s)
| | | | - Martin Schwemmle
- To whom correspondence should be addressed. Tel: +49 761 203 6526; Fax: +49 761 203 6626;
| | - Roland Marquet
- Correspondence may also be addressed to Roland Marquet. Tel: +33 3 88 41 70 54; Fax: +33 3 88 60 22 18;
| | - Hardin Bolte
- Institute of Virology, Medical Center – University of Freiburg, 79104 Freiburg, Germany,Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
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10
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Programmable antivirals targeting critical conserved viral RNA secondary structures from influenza A virus and SARS-CoV-2. Nat Med 2022; 28:1944-1955. [PMID: 35982307 PMCID: PMC10132811 DOI: 10.1038/s41591-022-01908-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/20/2022] [Indexed: 12/18/2022]
Abstract
Influenza A virus's (IAV's) frequent genetic changes challenge vaccine strategies and engender resistance to current drugs. We sought to identify conserved and essential RNA secondary structures within IAV's genome that are predicted to have greater constraints on mutation in response to therapeutic targeting. We identified and genetically validated an RNA structure (packaging stem-loop 2 (PSL2)) that mediates in vitro packaging and in vivo disease and is conserved across all known IAV isolates. A PSL2-targeting locked nucleic acid (LNA), administered 3 d after, or 14 d before, a lethal IAV inoculum provided 100% survival in mice, led to the development of strong immunity to rechallenge with a tenfold lethal inoculum, evaded attempts to select for resistance and retained full potency against neuraminidase inhibitor-resistant virus. Use of an analogous approach to target SARS-CoV-2, prophylactic administration of LNAs specific for highly conserved RNA structures in the viral genome, protected hamsters from efficient transmission of the SARS-CoV-2 USA_WA1/2020 variant. These findings highlight the potential applicability of this approach to any virus of interest via a process we term 'programmable antivirals', with implications for antiviral prophylaxis and post-exposure therapy.
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11
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Almeida F, Santos LA, Trigueiro-Louro JM, RebelodeAndrade H. Optimization of A(H1N1)pdm09 vaccine seed viruses: the source of PB1 and HA vRNA as a major determinant for antigen yield. Virus Res 2022; 315:198795. [DOI: 10.1016/j.virusres.2022.198795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 12/21/2022]
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12
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Miyamoto S, Muramoto Y, Shindo K, Fujita-Fujiharu Y, Morikawa T, Tamura R, Gilmore JL, Nakano M, Noda T. Contribution of RNA-RNA Interactions Mediated by the Genome Packaging Signals for the Selective Genome Packaging of Influenza A Virus. J Virol 2022; 96:e0164121. [PMID: 35044211 PMCID: PMC8941900 DOI: 10.1128/jvi.01641-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 01/12/2022] [Indexed: 11/20/2022] Open
Abstract
The influenza A virus genome is composed of eight single-stranded negative-sense viral RNA segments (vRNAs). The eight vRNAs are selectively packaged into each progeny virion. This process likely involves specific interactions between the vRNAs via segment-specific packaging signals located in both the 3'- and 5'-terminal regions of the respective vRNAs. To assess the importance of vRNA-vRNA interactions via packaging signals for selective genome packaging, we generated mutant viruses possessing silent mutations in the packaging signal region of the hemagglutinin (HA) vRNA. A mutant virus possessing silent mutations in nucleotides (nt) 1664 to 1676 resulted in defects in HA vRNA incorporation and showed a reduction in viral growth. After serial passage, the mutant virus acquired additional mutations in the 5'-terminal packaging signal regions of both the HA and polymerase basic 2 (PB2) vRNAs. These mutations contributed to the recovery of viral growth and HA vRNA packaging efficiency. In addition, an RNA-RNA interaction between the 5' ends of HA and PB2 vRNAs was confirmed in vitro, and this interaction was disrupted following the introduction of silent mutations in the HA vRNA. Thus, our results demonstrated that RNA-RNA interactions between the packaging signal regions of HA vRNA and PB2 vRNA are important for selective genome packaging. IMPORTANCE While numerous viral genomes comprise a single genome segment, the influenza A virus possesses eight segmented genomes. Influenza A virus can benefit from having a segmented genome because the segments can reassort with other strains of the influenza virus to create new genetically distinct strains. The influenza A virus efficiently incorporates one copy of each of its eight genomic segments per viral particle. However, the mechanism by which each segment is specifically selected is poorly understood. The genome segments contain RNA signals that facilitate the incorporation of segments into virus particles. These regions may facilitate specific interactions between the genome segments, creating an eight-segment complex, which can then be packaged into individual particles. In this study, we provide evidence that RNA signals contribute to specific interactions between two of the influenza virus genome segments.
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Affiliation(s)
- Sho Miyamoto
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Department of Molecular Virology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukiko Muramoto
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Keiko Shindo
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Yoko Fujita-Fujiharu
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Takeshi Morikawa
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Ryoma Tamura
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Jamie L. Gilmore
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Masahiro Nakano
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
| | - Takeshi Noda
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
- Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Japan
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13
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Bu L, Chen B, Xing L, Cai X, Liang S, Zhang L, Wang X, Song W. Generation of a pdmH1N1 2018 Influenza A Reporter Virus Carrying a mCherry Fluorescent Protein in the PA Segment. Front Cell Infect Microbiol 2022; 11:827790. [PMID: 35127568 PMCID: PMC8811159 DOI: 10.3389/fcimb.2021.827790] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 12/31/2021] [Indexed: 11/13/2022] Open
Abstract
Influenza A virus (IAV) is a major human pathogen associated with significant morbidity and mortality worldwide. Through serial passage in mice, we generated a recombinant pdmH1N1 2009 IAV, A/Guangdong/GLW/2018 (GLW/18-MA), which encodes an mCherry gene fused to the C-terminal of a polymerase acidic (PA) segment and demonstrated comparable growth kinetics to the wild-type. Nine mutations were identified in the GLW/18-MA genome: PA (I61M, E351G, and G631S), NP (E292G), HA1 (T164I), HA2 (N117S and P160S), NA (W61R), and NEP (K44R). The recombinant IAV reporter expresses mCherry, a red fluorescent protein, at a high level and maintains its genetic integrity after five generations of serial passages in Madin-Darby Canine Kidney cells (MDCK) cells. Moreover, the imaging is noninvasive and permits the monitoring of infection in living mice. Treatment with oseltamivir or baicalin followed by infection with the reporter IAV led to a decrease in fluorescent protein signal in living mice. This result demonstrates that the IAV reporter virus is a powerful tool to study viral pathogenicity and transmission and to develop and evaluate novel anti-viral drugs, inhibitors, and vaccines in the future.
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Affiliation(s)
- Ling Bu
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Boqian Chen
- Artemisinin Research Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lei Xing
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Xuejun Cai
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Shuhua Liang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Liying Zhang
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, China
| | - Xinhua Wang
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Artemisinin Research Center, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wenjun Song
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- Institute of Integration of Traditional and Western Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
- State Key Laboratory for Emerging Infectious Diseases, Department of Microbiology, and the Research Center of Infection and Immunology, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
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14
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Seshimo E, Momose F, Morikawa Y. Identification of the 5'-Terminal Packaging Signal of the H1N1 Influenza A Virus Neuraminidase Segment at Single-Nucleotide Resolution. Front Microbiol 2021; 12:709010. [PMID: 34456891 PMCID: PMC8385638 DOI: 10.3389/fmicb.2021.709010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/20/2021] [Indexed: 02/05/2023] Open
Abstract
The genome of the influenza A virus is an eight-segmented negative-strand RNA (vRNA). Progeny vRNAs replicated in the nucleus selectively assemble into a single set of eight different segments, probably in the cytoplasm, and are packaged into progeny virions at the cell membrane. In these processes, a region of approximately 100 nucleotides at both ends of each segment is thought to function as a selective assembly/packaging signal; however, the details of the mechanism, such as the required sequences, are still unknown. In this study, we focused on the 5'-terminus of the sixth neuraminidase gene segment vRNA (Seg.6) to identify the essential sequence for selective packaging. The 5'-terminal region of the A/Puerto Rico/8/34 strain Seg.6 was divided into seven regions of 15 nucleotides each from A to G, and mutations were introduced into each region by complementary base substitutions or synonymous codon substitutions. Mutant viruses were generated and compared for infectious titers, and the relative ratios of the eight segments packaged into virions were measured. We also ascertained whether mutant vRNA was eliminated by competitive packaging with wild-type vRNA. Mutations in the A-C regions reduced infectious titers and eliminated mutant vRNAs by competition with wild-type vRNA. Even under non-competitive conditions, the packaging efficiency of the A or B region mutant Seg.6 was reduced. Next, we designed an artificial vRNA with a 50-nucleotide duplication at the 5'-terminal region. Using this, a virus library was created by randomly replacing each region, which became an untranslated region (UTR), with complementary bases. After selecting proliferative viruses from the library, nine wild-type nucleotides in the A and B regions were identified as essential bases, and we found that these bases were highly conserved in Seg.6 vRNAs encoding the N1 subtype neuraminidase. From these results, we conclude that the identified bases function as the 5'-terminal packaging signal for the N1 subtype Seg.6 vRNA.
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Affiliation(s)
- Erika Seshimo
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan
| | - Fumitaka Momose
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan.,Ōmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
| | - Yuko Morikawa
- Graduate School of Infection Control Sciences, Kitasato University, Tokyo, Japan.,Ōmura Satoshi Memorial Institute, Kitasato University, Tokyo, Japan
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15
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Jones JE, Le Sage V, Padovani GH, Calderon M, Wright ES, Lakdawala SS. Parallel evolution between genomic segments of seasonal human influenza viruses reveals RNA-RNA relationships. eLife 2021; 10:66525. [PMID: 34448455 PMCID: PMC8523153 DOI: 10.7554/elife.66525] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 08/23/2021] [Indexed: 11/22/2022] Open
Abstract
The influenza A virus (IAV) genome consists of eight negative-sense viral RNA (vRNA) segments that are selectively assembled into progeny virus particles through RNA-RNA interactions. To explore putative intersegmental RNA-RNA relationships, we quantified similarity between phylogenetic trees comprising each vRNA segment from seasonal human IAV. Intersegmental tree similarity differed between subtype and lineage. While intersegmental relationships were largely conserved over time in H3N2 viruses, they diverged in H1N1 strains isolated before and after the 2009 pandemic. Surprisingly, intersegmental relationships were not driven solely by protein sequence, suggesting that IAV evolution could also be driven by RNA-RNA interactions. Finally, we used confocal microscopy to determine that colocalization of highly coevolved vRNA segments is enriched over other assembly intermediates at the nuclear periphery during productive viral infection. This study illustrates how putative RNA interactions underlying selective assembly of IAV can be interrogated with phylogenetics. The viruses responsible for influenza evolve rapidly during infection. Changes typically emerge in two key ways: through random mutations in the genetic sequence of the virus, or by reassortment. Reassortment can occur when two or more strains infect the same cell. Once in a cell, viral particles ‘open up’ to release their genetic material so it can make copies of itself using the cell’s machinery. The new copies of the genetic material of the virus are used to make new viral particles, which then envelop the genetic material and are released from the cell to infect other cells. If several strains of a virus infect the same cell, a new viral particle may pick up genetic segments from each of the infecting strains, creating a new strain via reassortment. Several factors are known to affect the success of the reassortment process. For example, if the new strain acquires a genetic defect that hinders its replication cycle, it is likely to die out quickly. Other times, this trading of genetic information can create a strain that is more resistant to the human immune system, allowing it to sweep across the globe and cause a deadly pandemic. However, a key part of the reassortment process that still remains unclear is how genome segments from two different influenza strains recognize each other before merging together to create hybrid daughter viruses. To explore this further, Jones et al. used a technique called fluorescence microscopy. They found that genome segments that evolved along similar paths were more likely to cluster in the same area inside infected cells, and therefore, more likely to be reassorted together into a new strain during assembly of daughter viruses. This suggests that assembly may guide the evolutionary path taken by individual genomic segments. Jones et al. also looked at the evolution of different genome segments collected from patients suffering from seasonal influenza, and found that these segments had a distinct evolutionary path to those in pandemic-causing strains. This research provides new insights into the role of reassortment in the evolution of influenza viruses during infection. In particular, it suggests that how the genome segments interact with one another may have a previously unknown and important role in guiding this evolution. These insights could be used to predict future reassortment events based on evolutionary relationships between influenza virus genomic segments, and may in the future be used as part of risk assessment tools to predict the emergence of new pandemic strains.
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Affiliation(s)
- Jennifer E Jones
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, United States.,Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, United States.,Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Valerie Le Sage
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, United States.,Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Gabriella H Padovani
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, United States.,Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Michael Calderon
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, United States
| | - Erik S Wright
- Center for Evolutionary Biology and Medicine, University of Pittsburgh, Pittsburgh, United States.,Department of Biomedical Informatics, University of Pittsburgh, Pittsburgh, United States
| | - Seema S Lakdawala
- Department of Microbiology & Molecular Genetics, University of Pittsburgh, Pittsburgh, United States.,Center for Vaccine Research, University of Pittsburgh School of Medicine, Pittsburgh, United States
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16
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Synergistic Effect between 3'-Terminal Noncoding and Adjacent Coding Regions of the Influenza A Virus Hemagglutinin Segment on Template Preference. J Virol 2021; 95:e0087821. [PMID: 34190596 DOI: 10.1128/jvi.00878-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The influenza A virus genome is comprised of eight single-stranded negative-sense viral RNA (vRNA) segments. Each of the eight vRNA segments contains segment-specific nonconserved noncoding regions (NCRs) of similar sequence and length in different influenza A virus strains. However, in the subtype-determinant segments, encoding hemagglutinin (HA) and neuraminidase (NA), the segment-specific noncoding regions are subtype specific, varying significantly in sequence and length at both the 3' and 5' termini among different subtypes. The significance of these subtype-specific noncoding regions (ssNCR) in the influenza virus replication cycle is not fully understood. In this study, we show that truncations of the 3'-end H1-subtype-specific noncoding region (H1-ssNCR) resulted in recombinant viruses with decreased HA vRNA replication and attenuated growth phenotype, although the vRNA replication was not affected in single-template RNP reconstitution assays. The attenuated viruses were unstable, and point mutations at nucleotide position 76 or 56 in the adjacent coding region of HA vRNA were found after serial passage. The mutations restored the HA vRNA replication and reversed the attenuated virus growth phenotype. We propose that the terminal noncoding and adjacent coding regions act synergistically to ensure optimal levels of HA vRNA replication in a multisegment environment. These results provide novel insights into the role of the 3'-end nonconserved noncoding regions and adjacent coding regions on template preference in multiple-segmented negative-strand RNA viruses. IMPORTANCE While most influenza A virus vRNA segments contain segment-specific nonconserved noncoding regions of similar length and sequence, these regions vary considerably both in length and sequence in the segments encoding HA and NA, the two major antigenic determinants of influenza A viruses. In this study, we investigated the function of the 3'-end H1-ssNCR and observed a synergistic effect between the 3'-end H1-ssNCR nucleotides and adjacent coding nucleotide(s) of the HA segment on template preference in a multisegment environment. The results unravel an additional level of complexity in the regulation of RNA replication in multiple-segmented negative-strand RNA viruses.
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17
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Kumar N, Kaushik R, Tennakoon C, Uversky VN, Longhi S, Zhang KYJ, Bhatia S. Insights into the evolutionary forces that shape the codon usage in the viral genome segments encoding intrinsically disordered protein regions. Brief Bioinform 2021; 22:6231751. [PMID: 33866372 DOI: 10.1093/bib/bbab145] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/17/2021] [Accepted: 03/26/2021] [Indexed: 12/22/2022] Open
Abstract
Intrinsically disordered regions/proteins (IDRs) are abundant across all the domains of life, where they perform important regulatory roles and supplement the biological functions of structured proteins/regions (SRs). Despite the multifunctionality features of IDRs, several interrogations on the evolution of viral genomic regions encoding IDRs in diverse viral proteins remain unreciprocated. To fill this gap, we benchmarked the findings of two most widely used and reliable intrinsic disorder prediction algorithms (IUPred2A and ESpritz) to a dataset of 6108 reference viral proteomes to unravel the multifaceted evolutionary forces that shape the codon usage in the viral genomic regions encoding for IDRs and SRs. We found persuasive evidence that the natural selection predominantly governs the evolution of codon usage in regions encoding IDRs by most of the viruses. In addition, we confirm not only that codon usage in regions encoding IDRs is less optimized for the protein synthesis machinery (transfer RNAs pool) of their host than for those encoding SRs, but also that the selective constraints imposed by codon bias sustain this reduced optimization in IDRs. Our analysis also establishes that IDRs in viruses are likely to tolerate more translational errors than SRs. All these findings hold true, irrespective of the disorder prediction algorithms used to classify IDRs. In conclusion, our study offers a novel perspective on the evolution of viral IDRs and the evolutionary adaptability to multiple taxonomically divergent hosts.
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Affiliation(s)
- Naveen Kumar
- Diagnostic & Vaccine Group, ICAR-National Institute of High Security Animal Diseases, Bhopal 462022, India
| | - Rahul Kaushik
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, 1-7-22 Suehiro, Yokohama, Kanagawa 230-0045, Japan
| | | | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.,Institute for Biological Instrumentation of the Russian Academy of Sciences, Federal Research Center 'Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences', Moscow region, Pushchino 142290, Russia
| | - Sonia Longhi
- Aix-Marseille Université and CNRS, Laboratoire Architecture et Fonction des Macromolecules Biologiques (AFMB), UMR 7257, Marseille, France
| | - Kam Y J Zhang
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, 1-7-22 Suehiro, Yokohama, Kanagawa 230-0045, Japan
| | - Sandeep Bhatia
- Diagnostic & Vaccine Group, ICAR-National Institute of High Security Animal Diseases, Bhopal 462022, India
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18
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Li X, Gu M, Zheng Q, Gao R, Liu X. Packaging signal of influenza A virus. Virol J 2021; 18:36. [PMID: 33596956 PMCID: PMC7890907 DOI: 10.1186/s12985-021-01504-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 02/02/2021] [Indexed: 12/15/2022] Open
Abstract
Influenza A virus (IAV) contains a genome with eight single-stranded, negative-sense RNA segments that encode 17 proteins. During its assembly, all eight separate viral RNA (vRNA) segments are incorporated into virions in a selective manner. Evidence suggested that the highly selective genome packaging mechanism relies on RNA-RNA or protein-RNA interactions. The specific structures of each vRNA that contribute to mediating the packaging of the vRNA into virions have been described and identified as packaging signals. Abundant research indicated that sequences required for genome incorporation are not series and are varied among virus genotypes. The packaging signals play important roles in determining the virus replication, genome incorporation and genetic reassortment of influenza A virus. In this review, we discuss recent studies on influenza A virus packaging signals to provide an overview of their characteristics and functions.
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Affiliation(s)
- Xiuli Li
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, China
| | - Min Gu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, China
| | - Qinmei Zheng
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, China
| | - Ruyi Gao
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, China
| | - Xiufan Liu
- Animal Infectious Disease Laboratory, College of Veterinary Medicine, Yangzhou University, 48 East Wenhui Road, Yangzhou, Jiangsu, China.
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19
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Piasecka J, Jarmolowicz A, Kierzek E. Organization of the Influenza A Virus Genomic RNA in the Viral Replication Cycle-Structure, Interactions, and Implications for the Emergence of New Strains. Pathogens 2020; 9:pathogens9110951. [PMID: 33203084 PMCID: PMC7696059 DOI: 10.3390/pathogens9110951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/13/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
The influenza A virus is a human pathogen causing respiratory infections. The ability of this virus to trigger seasonal epidemics and sporadic pandemics is a result of its high genetic variability, leading to the ineffectiveness of vaccinations and current therapies. The source of this variability is the accumulation of mutations in viral genes and reassortment enabled by its segmented genome. The latter process can induce major changes and the production of new strains with pandemic potential. However, not all genetic combinations are tolerated and lead to the assembly of complete infectious virions. Reports have shown that viral RNA segments co-segregate in particular circumstances. This tendency is a consequence of the complex and selective genome packaging process, which takes place in the final stages of the viral replication cycle. It has been shown that genome packaging is governed by RNA–RNA interactions. Intersegment contacts create a network, characterized by the presence of common and strain-specific interaction sites. Recent studies have revealed certain RNA regions, and conserved secondary structure motifs within them, which may play functional roles in virion assembly. Growing knowledge on RNA structure and interactions facilitates our understanding of the appearance of new genome variants, and may allow for the prediction of potential reassortment outcomes and the emergence of new strains in the future.
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20
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tenOever BR. Synthetic Virology: Building Viruses to Better Understand Them. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a038703. [PMID: 31871242 DOI: 10.1101/cshperspect.a038703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Generally comprised of less than a dozen components, RNA viruses can be viewed as well-designed genetic circuits optimized to replicate and spread within a given host. Understanding the molecular design that enables this activity not only allows one to disrupt these circuits to study their biology, but it provides a reprogramming framework to achieve novel outputs. Recent advances have enabled a "learning by building" approach to better understand virus biology and create valuable tools. Below is a summary of how modifying the preexisting genetic framework of influenza A virus has been used to track viral movement, understand virus replication, and identify host factors that engage this viral circuitry.
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Affiliation(s)
- Benjamin R tenOever
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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21
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Selective flexible packaging pathways of the segmented genome of influenza A virus. Nat Commun 2020; 11:4355. [PMID: 32859915 PMCID: PMC7455735 DOI: 10.1038/s41467-020-18108-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 07/30/2020] [Indexed: 12/20/2022] Open
Abstract
The genome of influenza A viruses (IAV) is encoded in eight distinct viral ribonucleoproteins (vRNPs) that consist of negative sense viral RNA (vRNA) covered by the IAV nucleoprotein. Previous studies strongly support a selective packaging model by which vRNP segments are bundling to an octameric complex, which is integrated into budding virions. However, the pathway(s) generating a complete genome bundle is not known. We here use a multiplexed FISH assay to monitor all eight vRNAs in parallel in human lung epithelial cells. Analysis of 3.9 × 105 spots of colocalizing vRNAs provides quantitative insights into segment composition of vRNP complexes and, thus, implications for bundling routes. The complexes rarely contain multiple copies of a specific segment. The data suggest a selective packaging mechanism with limited flexibility by which vRNPs assemble into a complete IAV genome. We surmise that this flexibility forms an essential basis for the development of reassortant viruses with pandemic potential.
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22
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Identification of genome-wide nucleotide sites associated with mammalian virulence in influenza A viruses. BIOSAFETY AND HEALTH 2020. [DOI: 10.1016/j.bsheal.2020.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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23
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Miyamoto S, Noda T. In vitro vRNA-vRNA interactions in the H1N1 influenza A virus genome. Microbiol Immunol 2020; 64:202-209. [PMID: 31840833 DOI: 10.1111/1348-0421.12766] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 01/15/2023]
Abstract
The genome of influenza A virus consists of eight-segmented, single-stranded, negative-sense viral RNAs (vRNAs). Each vRNA contains a central coding region that is flanked by noncoding regions. It has been shown that upon virion formation, the eight vRNAs are selectively packaged into progeny virions through segment-specific packaging signals that are located in both the terminal coding regions and adjacent noncoding regions of each vRNA. Although recent studies using next-generation sequencing suggest that multiple intersegment interactions are involved in genome packaging, contributions of the packaging signals to the intersegment interactions are not fully understood. Herein, using synthesized full-length vRNAs of H1N1 WSN (A/WSN/33 [H1N1]) virus and short vRNAs containing the packaging signal sequences, we performed in vitro RNA binding assays and identified 15 intersegment interactions among eight vRNAs, most of which were mediated by the 3'- and 5'-terminal regions. Interestingly, all eight vRNAs interacted with multiple other vRNAs, in that some bound to different vRNAs through their respective 3'- and 5'-terminal regions. These in vitro findings would be of use in future studies of in vivo vRNA-vRNA interactions during selective genome packaging.
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Affiliation(s)
- Sho Miyamoto
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Department of Molecular Virology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takeshi Noda
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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24
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Jacobs NT, Onuoha NO, Antia A, Steel J, Antia R, Lowen AC. Incomplete influenza A virus genomes occur frequently but are readily complemented during localized viral spread. Nat Commun 2019; 10:3526. [PMID: 31387995 PMCID: PMC6684657 DOI: 10.1038/s41467-019-11428-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 07/15/2019] [Indexed: 11/09/2022] Open
Abstract
Segmentation of viral genomes into multiple RNAs creates the potential for replication of incomplete viral genomes (IVGs). Here we use a single-cell approach to quantify influenza A virus IVGs and examine their fitness implications. We find that each segment of influenza A/Panama/2007/99 (H3N2) virus has a 58% probability of being replicated in a cell infected with a single virion. Theoretical methods predict that IVGs carry high costs in a well-mixed system, as 3.6 virions are required for replication of a full genome. Spatial structure is predicted to mitigate these costs, however, and experimental manipulations of spatial structure indicate that local spread facilitates complementation. A virus entirely dependent on co-infection was used to assess relevance of IVGs in vivo. This virus grows robustly in guinea pigs, but is less infectious and does not transmit. Thus, co-infection allows IVGs to contribute to within-host spread, but complete genomes may be critical for transmission.
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Affiliation(s)
- Nathan T Jacobs
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
| | - Nina O Onuoha
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
| | - Alice Antia
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
| | - John Steel
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Rustom Antia
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Anice C Lowen
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA.
- Emory-UGA Center of Excellence for Influenza Research and Surveillance, Emory University School of Medicine, Atlanta, GA, USA.
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25
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Dadonaite B, Gilbertson B, Knight ML, Trifkovic S, Rockman S, Laederach A, Brown LE, Fodor E, Bauer DLV. The structure of the influenza A virus genome. Nat Microbiol 2019; 4:1781-1789. [PMID: 31332385 DOI: 10.1038/s41564-019-0513-7] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/12/2019] [Indexed: 12/19/2022]
Abstract
Influenza A viruses (IAVs) constitute a major threat to human health. The IAV genome consists of eight single-stranded viral RNA segments contained in separate viral ribonucleoprotein (vRNP) complexes that are packaged together into a single virus particle. The structure of viral RNA is believed to play a role in assembling the different vRNPs into budding virions1-8 and in directing reassortment between IAVs9. Reassortment between established human IAVs and IAVs harboured in the animal reservoir can lead to the emergence of pandemic influenza strains to which there is little pre-existing immunity in the human population10,11. While previous studies have revealed the overall organization of the proteins within vRNPs, characterization of viral RNA structure using conventional structural methods is hampered by limited resolution and an inability to resolve dynamic components12,13. Here, we employ multiple high-throughput sequencing approaches to generate a global high-resolution structure of the IAV genome. We show that different IAV genome segments acquire distinct RNA conformations and form both intra- and intersegment RNA interactions inside influenza virions. We use our detailed map of IAV genome structure to provide direct evidence for how intersegment RNA interactions drive vRNP cosegregation during reassortment between different IAV strains. The work presented here is a roadmap both for the development of improved vaccine strains and for the creation of a framework to 'risk assess' reassortment potential to better predict the emergence of new pandemic influenza strains.
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Affiliation(s)
| | - Brad Gilbertson
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Michael L Knight
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Sanja Trifkovic
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Steven Rockman
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.,Seqirus Ltd, Parkville, Victoria, Australia
| | - Alain Laederach
- Department of Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Lorena E Brown
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia.
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
| | - David L V Bauer
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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Takizawa N, Ogura Y, Fujita Y, Noda T, Shigematsu H, Hayashi T, Kurokawa K. Local structural changes of the influenza A virus ribonucleoprotein complex by single mutations in the specific residues involved in efficient genome packaging. Virology 2019; 531:126-140. [PMID: 30875489 DOI: 10.1016/j.virol.2019.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/05/2019] [Accepted: 03/06/2019] [Indexed: 11/15/2022]
Abstract
The influenza A virus genome consists of eight single-stranded negative-sense RNA segments. The noncoding regions located at the 3'- and 5'- ends of each segment are necessary for genome packaging, and the terminal coding regions are required to precisely bundle the eight segments. However, the nucleotide residues important for genome bundling are not defined. Here, we introduced premature termination codons in the hemagglutinin (HA) or matrix protein 2 (M2) gene and constructed virus libraries containing random sequences in the terminal coding regions. Using these virus libraries, we identified nucleotide residues involved in efficient virus propagation. Viral genome packaging was impaired in viruses that contained single mutations at these identified residues. Furthermore, these single mutations altered the local structure of the viral ribonucleoprotein complex. Our results show that specific nucleotide residues in the viral protein coding region are involved in forming the precise structure of the viral ribonucleoprotein complex.
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Affiliation(s)
- Naoki Takizawa
- Laboratory of Virology, Institute of Microbial Chemistry (BIKAKEN), Tokyo, Japan.
| | - Yoshitoshi Ogura
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoko Fujita
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan; Laboratory of Ultrastructural Virology, Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Takeshi Noda
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan; Laboratory of Ultrastructural Virology, Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Hideki Shigematsu
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, Hyogo, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Ken Kurokawa
- Center for Information Biology, National Institute of Genetics, Shizuoka, Japan
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27
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Bolte H, Rosu ME, Hagelauer E, García-Sastre A, Schwemmle M. Packaging of the Influenza Virus Genome Is Governed by a Plastic Network of RNA- and Nucleoprotein-Mediated Interactions. J Virol 2019; 93:e01861-18. [PMID: 30463968 PMCID: PMC6363987 DOI: 10.1128/jvi.01861-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 11/15/2018] [Indexed: 11/20/2022] Open
Abstract
The genome of influenza A virus is organized into eight ribonucleoproteins, each composed of a distinct RNA segment bound by the viral polymerase and oligomeric viral nucleoprotein. Packaging sequences unique to each RNA segment together with specific nucleoprotein amino acids are thought to ensure the precise incorporation of these eight ribonucleoproteins into single virus particles, and yet the underlying interaction network remains largely unexplored. We show here that the genome packaging mechanism of an H7N7 subtype influenza A virus widely tolerates the mutation of individual packaging sequences in three different RNA segments. However, combinations of these modified RNA segments cause distinct genome packaging defects, marked by the absence of specific RNA segment subsets from the viral particles. Furthermore, we find that combining a single mutated packaging sequence with sets of specific nucleoprotein amino acid substitutions greatly impairs the viral genome packaging process. Along with previous reports, our data propose that influenza A virus uses a redundant and plastic network of RNA-RNA and potentially RNA-nucleoprotein interactions to coordinately incorporate its segmented genome into virions.IMPORTANCE The genome of influenza A virus is organized into eight viral ribonucleoproteins (vRNPs); this provides evolutionary advantages but complicates genome packaging. Although it has been shown that RNA packaging sequences and specific amino acids in the viral nucleoprotein (NP), both components of each vRNP, ensure selective packaging of one copy of each vRNP per virus particle, the required RNA-RNA and RNA-NP interactions remain largely elusive. We identified that the genome packaging mechanism tolerates the mutation of certain individual RNA packaging sequences, while their combined mutation provokes distinct genome packaging defects. Moreover, we found that seven specific amino acid substitutions in NP impair the function of RNA packaging sequences and that this defect is partially restored by another NP amino acid change. Collectively, our data indicate that packaging of the influenza A virus genome is controlled by a redundant and plastic network of RNA/protein interactions, which may facilitate natural reassortment processes.
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Affiliation(s)
- Hardin Bolte
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Miruna E Rosu
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Department of Viroscience, Postgraduate School Molecular Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Elena Hagelauer
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Faculty of Biology, University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
- Department of Medicine, Division of Infectious Diseases, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Martin Schwemmle
- Institute of Virology, Medical Center University of Freiburg, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
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28
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Learning the sequence of influenza A genome assembly during viral replication using point process models and fluorescence in situ hybridization. PLoS Comput Biol 2019; 15:e1006199. [PMID: 30689627 PMCID: PMC6366722 DOI: 10.1371/journal.pcbi.1006199] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 02/07/2019] [Accepted: 11/20/2018] [Indexed: 11/19/2022] Open
Abstract
Within influenza virus infected cells, viral genomic RNA are selectively packed into progeny virions, which predominantly contain a single copy of 8 viral RNA segments. Intersegmental RNA-RNA interactions are thought to mediate selective packaging of each viral ribonucleoprotein complex (vRNP). Clear evidence of a specific interaction network culminating in the full genomic set has yet to be identified. Using multi-color fluorescence in situ hybridization to visualize four vRNP segments within a single cell, we developed image-based models of vRNP-vRNP spatial dependence. These models were used to construct likely sequences of vRNP associations resulting in the full genomic set. Our results support the notion that selective packaging occurs during cytoplasmic transport and identifies the formation of multiple distinct vRNP sub-complexes that likely form as intermediate steps toward full genomic inclusion into a progeny virion. The methods employed demonstrate a statistically driven, model based approach applicable to other interaction and assembly problems.
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29
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Kumar N, Kulkarni DD, Lee B, Kaushik R, Bhatia S, Sood R, Pateriya AK, Bhat S, Singh VP. Evolution of Codon Usage Bias in Henipaviruses Is Governed by Natural Selection and Is Host-Specific. Viruses 2018; 10:v10110604. [PMID: 30388838 PMCID: PMC6266499 DOI: 10.3390/v10110604] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/28/2018] [Accepted: 10/30/2018] [Indexed: 11/16/2022] Open
Abstract
Hendra virus (HeV) and Nipah virus (NiV) are among a group of emerging bat-borne paramyxoviruses that have crossed their species-barrier several times by infecting several hosts with a high fatality rate in human beings. Despite the fatal nature of their infection, a comprehensive study to explore their evolution and adaptation in different hosts is lacking. A study of codon usage patterns in henipaviruses may provide some fruitful insight into their evolutionary processes of synonymous codon usage and host-adapted evolution. Here, we performed a systematic evolutionary and codon usage bias analysis of henipaviruses. We found a low codon usage bias in the coding sequences of henipaviruses and that natural selection, mutation pressure, and nucleotide compositions shapes the codon usage patterns of henipaviruses, with natural selection being more important than the others. Also, henipaviruses showed the highest level of adaptation to bats of the genus Pteropus in the codon adaptation index (CAI), relative to the codon de-optimization index (RCDI), and similarity index (SiD) analyses. Furthermore, a comparison to recently identified henipa-like viruses indicated a high tRNA adaptation index of henipaviruses for human beings, mainly due to F, G and L proteins. Consequently, the study concedes the substantial emergence of henipaviruses in human beings, particularly when paired with frequent exposure to direct/indirect bat excretions.
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Affiliation(s)
- Naveen Kumar
- National Institute of High Security Animal Diseases, Bhopal 462022, India.
| | - Diwakar D Kulkarni
- National Institute of High Security Animal Diseases, Bhopal 462022, India.
| | - Benhur Lee
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Rahul Kaushik
- Supercomputing Facility for Bioinformatics & Computational Biology, Indian Institute of Technology, Delhi 110016, India.
- Laboratory for Structural Bioinformatics, Center for Biosystems Dynamics Research, RIKEN, Kanagawa 2300045, Japan.
| | - Sandeep Bhatia
- National Institute of High Security Animal Diseases, Bhopal 462022, India.
| | - Richa Sood
- National Institute of High Security Animal Diseases, Bhopal 462022, India.
| | | | | | - Vijendra Pal Singh
- National Institute of High Security Animal Diseases, Bhopal 462022, India.
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30
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Avian Influenza Virus PB1 Gene in H3N2 Viruses Evolved in Humans To Reduce Interferon Inhibition by Skewing Codon Usage toward Interferon-Altered tRNA Pools. mBio 2018; 9:mBio.01222-18. [PMID: 29970470 PMCID: PMC6030557 DOI: 10.1128/mbio.01222-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Influenza A viruses cause an annual contagious respiratory disease in humans and are responsible for periodic high-mortality human pandemics. Pandemic influenza A viruses usually result from the reassortment of gene segments between human and avian influenza viruses. These avian influenza virus gene segments need to adapt to humans. Here we focus on the human adaptation of the synonymous codons of the avian influenza virus PB1 gene of the 1968 H3N2 pandemic virus. We generated recombinant H3N2 viruses differing only in codon usage of PB1 mRNA and demonstrated that codon usage of the PB1 mRNA of recent H3N2 virus isolates enhances replication in interferon (IFN)-treated human cells without affecting replication in untreated cells, thereby partially alleviating the interferon-induced antiviral state. High-throughput sequencing of tRNA pools explains the reduced inhibition of replication by interferon: the levels of some tRNAs differ between interferon-treated and untreated human cells, and evolution of the codon usage of H3N2 PB1 mRNA is skewed toward interferon-altered human tRNA pools. Consequently, the avian influenza virus-derived PB1 mRNAs of modern H3N2 viruses have acquired codon usages that better reflect tRNA availabilities in IFN-treated cells. Our results indicate that the change in tRNA availabilities resulting from interferon treatment is a previously unknown aspect of the antiviral action of interferon, which has been partially overcome by human-adapted H3N2 viruses. Pandemic influenza A viruses that cause high human mortality usually result from reassortment of gene segments between human and avian influenza viruses. These avian influenza virus gene segments need to adapt to humans. Here we focus on the human adaptation of the avian influenza virus PB1 gene that was incorporated into the 1968 H3N2 pandemic virus. We demonstrate that the coding sequence of the PB1 mRNA of modern H3N2 viruses enhances replication in human cells in which interferon has activated a potent antiviral state. Reduced interferon inhibition results from evolution of PB1 mRNA codons skewed toward the pools of tRNAs in interferon-treated human cells, which, as shown here, differ significantly from the tRNA pools in untreated human cells. Consequently, avian influenza virus-derived PB1 mRNAs of modern H3N2 viruses have acquired codon usages that better reflect tRNA availabilities in IFN-treated cells and are translated more efficiently.
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31
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Pan W, Dong J, Chen P, Zhang B, Li Z, Chen L. Development and application of bioluminescence imaging for the influenza A virus. J Thorac Dis 2018; 10:S2230-S2237. [PMID: 30116602 DOI: 10.21037/jtd.2018.02.35] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Influenza A viruses (IAVs) cause seasonal epidemics and intermittent pandemics which threaten human health. Conventional assays cannot meet the demands for rapid and sensitive detection of viral spread and pathogenesis in real time cannot be used for high-throughput screens of novel antivirals. Bioluminescence imaging (BLI) has emerged as a powerful tool in the study of infectious diseases in animal models. The advent of influenza reverse genetics has enabled the incorporation of bioluminescent reporter proteins into replication-competent IAVs. This review briefly describes the current development and applications of bioluminescence in the study of viral infections and antiviral therapeutics for IAVs. BLI is expected to substantially accelerate the basic and applied research of IAV both in vitro and in vivo.
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Affiliation(s)
- Weiqi Pan
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510182, China
| | - Ji Dong
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510182, China
| | - Peihai Chen
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China.,Institute of Health Sciences, Anhui University, Hefei 230601, China
| | - Beiwu Zhang
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Zhixia Li
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Ling Chen
- State Key Laboratory of Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510182, China.,Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
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32
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Conserved secondary structures predicted within the 5′ packaging signal region of influenza A virus PB2 segment. Meta Gene 2018. [DOI: 10.1016/j.mgene.2017.11.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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33
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Williams GD, Townsend D, Wylie KM, Kim PJ, Amarasinghe GK, Kutluay SB, Boon ACM. Nucleotide resolution mapping of influenza A virus nucleoprotein-RNA interactions reveals RNA features required for replication. Nat Commun 2018; 9:465. [PMID: 29386621 PMCID: PMC5792457 DOI: 10.1038/s41467-018-02886-w] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 01/04/2018] [Indexed: 02/03/2023] Open
Abstract
Influenza A virus nucleoprotein (NP) association with viral RNA (vRNA) is essential for packaging, but the pattern of NP binding to vRNA is unclear. Here we applied photoactivatable ribonucleoside enhanced cross-linking and immunoprecipitation (PAR-CLIP) to assess the native-state of NP-vRNA interactions in infected human cells. NP binds short fragments of RNA (~12 nucleotides) non-uniformly and without apparent sequence specificity. Moreover, NP binding is reduced at specific locations within the viral genome, including regions previously identified as required for viral genome segment packaging. Synonymous mutations designed to alter the predicted RNA structures in these low-NP-binding regions impact genome packaging and result in virus attenuation, whereas control mutations or mutagenesis of NP-bound regions have no effect. Finally, we demonstrate that the sequence conservation of low-NP-binding regions is required in multiple genome segments for propagation of diverse mammalian and avian IAV in host cells.
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Affiliation(s)
- Graham D Williams
- Department of Medicine at Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Molecular Microbiology at Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Dana Townsend
- Department of Molecular Microbiology at Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Kristine M Wylie
- Department of Pediatrics at Washington University School of Medicine, St Louis, MO, 63110, USA
- The McDonnell Genome Institute at Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Preston J Kim
- Department of Pathology and Immunology at Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology at Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Biochemistry and Biophysics at Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Sebla B Kutluay
- Department of Molecular Microbiology at Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Adrianus C M Boon
- Department of Medicine at Washington University School of Medicine, St Louis, MO, 63110, USA.
- Department of Molecular Microbiology at Washington University School of Medicine, St Louis, MO, 63110, USA.
- Department of Pathology and Immunology at Washington University School of Medicine, St Louis, MO, 63110, USA.
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34
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Noda T, Murakami S, Nakatsu S, Imai H, Muramoto Y, Shindo K, Sagara H, Kawaoka Y. Importance of the 1+7 configuration of ribonucleoprotein complexes for influenza A virus genome packaging. Nat Commun 2018; 9:54. [PMID: 29302061 PMCID: PMC5754346 DOI: 10.1038/s41467-017-02517-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 12/06/2017] [Indexed: 12/31/2022] Open
Abstract
The influenza A virus genome is composed of eight single-stranded negative-sense RNAs. Eight distinct viral RNA segments (vRNAs) are selectively packaged into progeny virions, with eight vRNAs in ribonucleoprotein complexes (RNPs) arranged in a specific “1+7” pattern, that is, one central RNP surrounded by seven RNPs. Here we report the genome packaging of an artificially generated seven-segment virus that lacks the hemagglutinin (HA) vRNA. Electron microscopy shows that, even in the presence of only seven vRNAs, the virions efficiently package eight RNPs arranged in the same “1+7” pattern as wild-type virions. Next-generation sequencing reveals that the virions specifically incorporate host-derived 18S and 28S ribosomal RNAs (rRNAs) seemingly as the eighth RNP in place of the HA vRNA. These findings highlight the importance of the assembly of eight RNPs into a specific “1+7” configuration for genome packaging in progeny virions and suggest a potential role for cellular RNAs in viral genome packaging. Influenza A virus (IAV) packages its eight genomic RNA segments in a specific “1+7” pattern. Here, the authors generate IAV that lack one RNA segment and show that ribosomal RNA is packaged in place of the eighth segment, suggesting that the 1+7 pattern is important for particle production.
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Affiliation(s)
- Takeshi Noda
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan. .,International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan. .,PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan. .,Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan. .,Laboratory of Ultrastructural Virology, Graduate School of Biostudies, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan.
| | - Shin Murakami
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.,Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Sumiho Nakatsu
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Hirotaka Imai
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.,Department of Biological Informatics and Experimental Therapeutics, Graduate School of Medicine, Akita University, Akita, 010-8543, Japan
| | - Yukiko Muramoto
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.,Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Keiko Shindo
- Laboratory of Ultrastructural Virology, Institute for Frontier Life and Medical Sciences, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hiroshi Sagara
- Medical Proteomics Laboratory, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
| | - Yoshihiro Kawaoka
- Division of Virology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan. .,International Research Center for Infectious Diseases, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan. .,Department of Pathological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, 53771, USA.
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35
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Chou YY, Lionnet T. Single-Molecule Sensitivity RNA FISH Analysis of Influenza Virus Genome Trafficking. Methods Mol Biol 2018; 1836:195-211. [PMID: 30151575 DOI: 10.1007/978-1-4939-8678-1_10] [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] [Indexed: 12/04/2022]
Abstract
Influenza A virus is an enveloped virus with a segmented genome consisting of eight negative-sense, single-stranded RNAs. Accumulating evidence has revealed that influenza viruses selectively package their genomes. However, less is known about how different viral RNA segments are selected for incorporation into progeny virions. Understanding the trafficking routes and assembly process of various viral RNA segments during infection will shed light on the mechanisms of selective genome packaging for influenza A viruses. This chapter describes the single-molecule sensitivity RNA fluorescence in situ hybridization assay (smFISH) for influenza viral RNAs, a method used to analyze the distributions and trafficking of viral RNAs in infected cells with segment specificity. Hybridization using 20 or more short fluorescently labeled DNA probes allows the detection of viral RNAs with single-molecule sensitivity. The following imaging analyses provide information regarding quantitative measurements of vRNA abundance and the relative positions of the different viral RNA segments in cells. This chapter also includes a protocol for combining immunofluorescence techniques with smFISH, which is useful to analyze the positions of viral RNAs relative to viral/cellular proteins in infected cells.
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Affiliation(s)
- Yi-Ying Chou
- Program in Cellular and Molecular Medicine, Department of Cell Biology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA.
| | - Timothée Lionnet
- Department of Cell Biology, Institute for Systems Genetics, Langone Medical Center, New York University, New York, NY, USA.
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36
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Lakdawala SS, Fodor E, Subbarao K. Moving On Out: Transport and Packaging of Influenza Viral RNA into Virions. Annu Rev Virol 2017; 3:411-427. [PMID: 27741407 DOI: 10.1146/annurev-virology-110615-042345] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Influenza A viruses bear an eight-segmented single-stranded negative-sense RNA genome that is replicated in the nucleus. Newly synthesized viral RNA (vRNA) segments are exported from the nucleus and transported to the plasma membrane for packaging into progeny virions. Influenza viruses exploit many host proteins during these events, and this is the portion of the viral life cycle when genetic reassortment among influenza viruses occurs. Reassortment among influenza A viruses allows viruses to expand their host range, virulence, and pandemic potential. This review covers recent studies on the export of vRNAs from the nucleus and their transport through the cytoplasm, progressive assembly, and packaging into progeny virus particles. Understanding these events and the constraints on genetic reassortment has implications for assessment of the pandemic potential of newly emerged influenza viruses, for vaccine production, for determination of viral fitness, and for identification of novel therapeutic targets.
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Affiliation(s)
- Seema S Lakdawala
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Kanta Subbarao
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892;
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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: 4] [Impact Index Per Article: 0.6] [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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Urbaniak K, Markowska-Daniel I, Kowalczyk A, Kwit K, Pomorska-Mól M, Frącek B, Pejsak Z. Reassortment process after co-infection of pigs with avian H1N1 and swine H3N2 influenza viruses. BMC Vet Res 2017; 13:215. [PMID: 28688454 PMCID: PMC5501944 DOI: 10.1186/s12917-017-1137-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 06/30/2017] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The influenza A virus is highly variable, which, to some degree, is caused by the reassortment of viral genetic material. This process plays a major role in the generation of novel influenza virus strains that can emerge in a new host population. Due to the susceptibility of pigs to infections with avian, swine and human influenza viruses, they are considered intermediate hosts for the adaptation of the avian influenza virus to humans. In order to test the reassortment process in pigs, they were co-infected with H3N2 A/swine/Gent/172/2008 (Gent/08) and H1N1 A/duck/Italy/1447/2005 (Italy/05) and co-housed with a group of naïve piglets. RESULTS The Gent/08 strains dominated over Italy/05, but reassortment occurred. The reassortant strains of the H1N1 subtype (12.5%) with one gene (NP or M) of swine-origin were identified in the nasal discharge of the contact-exposed piglets. CONCLUSIONS These results demonstrate that despite their low efficiency, genotypically and phenotypically different influenza A viruses can undergo genetic exchange during co-infection of pigs.
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Affiliation(s)
- Kinga Urbaniak
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland.
| | - Iwona Markowska-Daniel
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland
- Present Address: Laboratory of Veterinary Epidemiology and Economics, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, 159c Nowoursynowska Street, 02-776, Warsaw, Poland
| | - Andrzej Kowalczyk
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland
- Present Address: Wrocław Research Centre EIT+, 147 Stabłowicka Street, 54-066, Wrocław, Poland
| | - Krzysztof Kwit
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland
| | - Małgorzata Pomorska-Mól
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland
| | - Barbara Frącek
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland
| | - Zygmunt Pejsak
- Department of Swine Diseases, National Veterinary Research Institute, 57 Partyzantów Avenue, 24-100, Puławy, Poland
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Heterologous Packaging Signals on Segment 4, but Not Segment 6 or Segment 8, Limit Influenza A Virus Reassortment. J Virol 2017; 91:JVI.00195-17. [PMID: 28331085 DOI: 10.1128/jvi.00195-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 03/17/2017] [Indexed: 01/07/2023] Open
Abstract
Influenza A virus (IAV) RNA packaging signals serve to direct the incorporation of IAV gene segments into virus particles, and this process is thought to be mediated by segment-segment interactions. These packaging signals are segment and strain specific, and as such, they have the potential to impact reassortment outcomes between different IAV strains. Our study aimed to quantify the impact of packaging signal mismatch on IAV reassortment using the human seasonal influenza A/Panama/2007/99 (H3N2) and pandemic influenza A/Netherlands/602/2009 (H1N1) viruses. Focusing on the three most divergent segments, we constructed pairs of viruses that encoded identical proteins but differed in the packaging signal regions on a single segment. We then evaluated the frequency with which segments carrying homologous versus heterologous packaging signals were incorporated into reassortant progeny viruses. We found that, when segment 4 (HA) of coinfecting parental viruses was modified, there was a significant preference for the segment containing matched packaging signals relative to the background of the virus. This preference was apparent even when the homologous HA constituted a minority of the HA segment population available in the cell for packaging. Conversely, when segment 6 (NA) or segment 8 (NS) carried modified packaging signals, there was no significant preference for homologous packaging signals. These data suggest that movement of NA and NS segments between the human H3N2 and H1N1 lineages is unlikely to be restricted by packaging signal mismatch, while movement of the HA segment would be more constrained. Our results indicate that the importance of packaging signals in IAV reassortment is segment dependent.IMPORTANCE Influenza A viruses (IAVs) can exchange genes through reassortment. This process contributes to both the highly diverse population of IAVs found in nature and the formation of novel epidemic and pandemic IAV strains. Our study sought to determine the extent to which IAV packaging signal divergence impacts reassortment between seasonal IAVs. Our knowledge in this area is lacking, and insight into the factors that influence IAV reassortment will inform and strengthen ongoing public health efforts to anticipate the emergence of new viruses. We found that the packaging signals on the HA segment, but not the NA or NS segments, restricted IAV reassortment. Thus, the packaging signals of the HA segment could be an important factor in determining the likelihood that two IAV strains of public health interest will undergo reassortment.
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Crescenzo-Chaigne B, Barbezange CVS, Léandri S, Roquin C, Berthault C, van der Werf S. Incorporation of the influenza A virus NA segment into virions does not require cognate non-coding sequences. Sci Rep 2017; 7:43462. [PMID: 28240311 PMCID: PMC5327478 DOI: 10.1038/srep43462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 01/25/2017] [Indexed: 12/21/2022] Open
Abstract
For each influenza virus genome segment, the coding sequence is flanked by non-coding (NC) regions comprising shared, conserved sequences and specific, non-conserved sequences. The latter and adjacent parts of the coding sequence are involved in genome packaging, but the precise role of the non-conserved NC sequences is still unclear. The aim of this study is to better understand the role of the non-conserved non-coding sequences in the incorporation of the viral segments into virions. The NA-segment NC sequences were systematically replaced by those of the seven other segments. Recombinant viruses harbouring two segments with identical NC sequences were successfully rescued. Virus growth kinetics and serial passages were performed, and incorporation of the viral segments was tested by real-time RT-PCR. An initial virus growth deficiency correlated to a specific defect in NA segment incorporation. Upon serial passages, growth properties were restored. Sequencing revealed that the replacing 5'NC sequence length drove the type of mutations obtained. With sequences longer than the original, point mutations in the coding region with or without substitutions in the 3'NC region were detected. With shorter sequences, insertions were observed in the 5'NC region. Restoration of viral fitness was linked to restoration of the NA segment incorporation.
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Affiliation(s)
- Bernadette Crescenzo-Chaigne
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Paris, France.,Unité Mixte de Recherche 3569, Centre National de la Recherche Scientifique, Paris, France.,Université Paris-Diderot Sorbonne-Paris-Cité, Paris, France
| | - Cyril V S Barbezange
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Paris, France.,Unité Mixte de Recherche 3569, Centre National de la Recherche Scientifique, Paris, France.,Université Paris-Diderot Sorbonne-Paris-Cité, Paris, France
| | - Stéphane Léandri
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Paris, France.,Unité Mixte de Recherche 3569, Centre National de la Recherche Scientifique, Paris, France.,Université Paris-Diderot Sorbonne-Paris-Cité, Paris, France
| | - Camille Roquin
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Paris, France.,Unité Mixte de Recherche 3569, Centre National de la Recherche Scientifique, Paris, France.,Université Paris-Diderot Sorbonne-Paris-Cité, Paris, France
| | - Camille Berthault
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Paris, France.,Unité Mixte de Recherche 3569, Centre National de la Recherche Scientifique, Paris, France.,Université Paris-Diderot Sorbonne-Paris-Cité, Paris, France
| | - Sylvie van der Werf
- Institut Pasteur, Unité de Génétique Moléculaire des Virus à ARN, Paris, France.,Unité Mixte de Recherche 3569, Centre National de la Recherche Scientifique, Paris, France.,Université Paris-Diderot Sorbonne-Paris-Cité, Paris, France
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41
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Sobel Leonard A, McClain MT, Smith GJD, Wentworth DE, Halpin RA, Lin X, Ransier A, Stockwell TB, Das SR, Gilbert AS, Lambkin-Williams R, Ginsburg GS, Woods CW, Koelle K, Illingworth CJR. The effective rate of influenza reassortment is limited during human infection. PLoS Pathog 2017; 13:e1006203. [PMID: 28170438 PMCID: PMC5315410 DOI: 10.1371/journal.ppat.1006203] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 02/17/2017] [Accepted: 01/26/2017] [Indexed: 12/31/2022] Open
Abstract
We characterise the evolutionary dynamics of influenza infection described by viral sequence data collected from two challenge studies conducted in human hosts. Viral sequence data were collected at regular intervals from infected hosts. Changes in the sequence data observed across time show that the within-host evolution of the virus was driven by the reversion of variants acquired during previous passaging of the virus. Treatment of some patients with oseltamivir on the first day of infection did not lead to the emergence of drug resistance variants in patients. Using an evolutionary model, we inferred the effective rate of reassortment between viral segments, measuring the extent to which randomly chosen viruses within the host exchange genetic material. We find strong evidence that the rate of effective reassortment is low, such that genetic associations between polymorphic loci in different segments are preserved during the course of an infection in a manner not compatible with epistasis. Combining our evidence with that of previous studies we suggest that spatial heterogeneity in the viral population may reduce the extent to which reassortment is observed. Our results do not contradict previous findings of high rates of viral reassortment in vitro and in small animal studies, but indicate that in human hosts the effective rate of reassortment may be substantially more limited. The influenza virus is an important cause of disease in the human population. During the course of an infection the virus can evolve rapidly. An important mechanism of viral evolution is reassortment, whereby different segments of the influenza genome are shuffled with other segments, producing new viral combinations. Here we study natural selection and reassortment during the course of infections occurring in human hosts. Examining viral genome sequence data from these infections, we note that genetic variants that were acquired during the growth of viruses in culture are selected against in the human host. In addition, we find evidence that the effective rate of reassortment is low. We suggest that the spatial separation between viruses in different parts of the host airway may limit the extent to which genetically distinct segments reassort with one another. Within the global population of influenza viruses, reassortment remains an important factor. However, reassortment is not so rapid as to exclude the possibility of interactions between genome segments affecting the course of influenza evolution during a single infection.
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Affiliation(s)
- Ashley Sobel Leonard
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Micah T. McClain
- Duke Center for Applied Genomics and Precision Medicine, Durham, North Carolina, United States of America
| | - Gavin J. D. Smith
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore
| | - David E. Wentworth
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Rebecca A. Halpin
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Xudong Lin
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Amy Ransier
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | | | - Suman R. Das
- J. Craig Venter Institute, Rockville, Maryland, United States of America
| | - Anthony S. Gilbert
- hVivo PLC, The QMB Innovation Centre, Queen Mary, University of London, London, United Kingdom
| | - Rob Lambkin-Williams
- hVivo PLC, The QMB Innovation Centre, Queen Mary, University of London, London, United Kingdom
| | - Geoffrey S. Ginsburg
- Duke Center for Applied Genomics and Precision Medicine, Durham, North Carolina, United States of America
| | - Christopher W. Woods
- Duke Center for Applied Genomics and Precision Medicine, Durham, North Carolina, United States of America
| | - Katia Koelle
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Christopher J. R. Illingworth
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
- Department of Applied Maths and Theoretical Physics, Centre for Mathematical Sciences, Wilberforce Road, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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42
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Abstract
The development of arenavirus reverse genetics has provided investigators with a novel and powerful approach for the investigation of the arenavirus molecular and cell biology. The use of cell-based minigenome systems has allowed examining the cis- and trans-acting factors involved in arenavirus replication and transcription, and the identification of novel anti-arenaviral drug targets without requiring the use of live forms of arenaviruses. Likewise, it is now feasible to rescue infectious arenaviruses entirely from cloned cDNAs containing predetermined mutations in their genomes to investigate virus-host interactions and mechanisms of pathogenesis. These advances in arenavirus genetics have also facilitated screens to identify anti-arenaviral drugs and the pursuit of novel strategies to generate live-attenuated arenavirus vaccine candidates. Moreover, the generation of tri-segmented (r3) arenaviruses expressing foreign genes of interest (GOI) has opened the possibility of implementing live-attenuated arenaviruses-based vaccine vector approaches. In this chapter, we will summarize the implementation of plasmid-based reverse genetics techniques for the development of r3 arenaviruses expressing foreign GOI for their implementation as vaccine vectors.
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Affiliation(s)
- Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY, 14642, USA.
| | - Juan Carlos de la Torre
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, 92037, USA.
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43
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A conserved influenza A virus nucleoprotein code controls specific viral genome packaging. Nat Commun 2016; 7:12861. [PMID: 27650413 PMCID: PMC5035998 DOI: 10.1038/ncomms12861] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 08/10/2016] [Indexed: 11/10/2022] Open
Abstract
Packaging of the eight genomic RNA segments of influenza A viruses (IAV) into viral particles is coordinated by segment-specific packaging sequences. How the packaging signals regulate the specific incorporation of each RNA segment into virions and whether other viral or host factors are involved in this process is unknown. Here, we show that distinct amino acids of the viral nucleoprotein (NP) are required for packaging of specific RNA segments. This was determined by studying the NP of a bat influenza A-like virus, HL17NL10, in the context of a conventional IAV (SC35M). Replacement of conserved SC35M NP residues by those of HL17NL10 NP resulted in RNA packaging defective IAV. Surprisingly, substitution of these conserved SC35M amino acids with HL17NL10 NP residues led to IAV with altered packaging efficiencies for specific subsets of RNA segments. This suggests that NP harbours an amino acid code that dictates genome packaging into infectious virions. The nucleotide sequence of the eight genomic RNA segments of influenza A virus provides essential packaging signals, but how these sequences are recognized is unknown. Here, Moreira et al. identify conserved amino acids in the viral nucleoprotein that regulate packaging of RNA segments.
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44
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Gilbertson B, Zheng T, Gerber M, Printz-Schweigert A, Ong C, Marquet R, Isel C, Rockman S, Brown L. Influenza NA and PB1 Gene Segments Interact during the Formation of Viral Progeny: Localization of the Binding Region within the PB1 Gene. Viruses 2016; 8:v8080238. [PMID: 27556479 PMCID: PMC4997600 DOI: 10.3390/v8080238] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/16/2016] [Accepted: 08/16/2016] [Indexed: 11/19/2022] Open
Abstract
The influenza A virus genome comprises eight negative-sense viral RNAs (vRNAs) that form individual ribonucleoprotein (RNP) complexes. In order to incorporate a complete set of each of these vRNAs, the virus uses a selective packaging mechanism that facilitates co-packaging of specific gene segments but whose molecular basis is still not fully understood. Recently, we used a competitive transfection model where plasmids encoding the A/Puerto Rico/8/34 (PR8) and A/Udorn/307/72 (Udorn) PB1 gene segments were competed to show that the Udorn PB1 gene segment is preferentially co-packaged into progeny virions with the Udorn NA gene segment. Here we created chimeric PB1 genes combining both Udorn and PR8 PB1 sequences to further define the location within the Udorn PB1 gene that drives co-segregation of these genes and show that nucleotides 1776–2070 of the PB1 gene are crucial for preferential selection. In vitro assays examining specific interactions between Udorn NA vRNA and purified vRNAs transcribed from chimeric PB1 genes also supported the importance of this region in the PB1-NA interaction. Hence, this work identifies an association between viral genes that are co-selected during packaging. It also reveals a region potentially important in the RNP-RNP interactions within the supramolecular complex that is predicted to form prior to budding to allow one of each segment to be packaged in the viral progeny. Our study lays the foundation to understand the co-selection of specific genes, which may be critical to the emergence of new viruses with pandemic potential.
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Affiliation(s)
- Brad Gilbertson
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute of Infection and Immunity, Parkville 3010, Victoria, Australia.
| | - Tian Zheng
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute of Infection and Immunity, Parkville 3010, Victoria, Australia.
| | - Marie Gerber
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 rue René Descartes, Strasbourg 67084, France.
| | - Anne Printz-Schweigert
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 rue René Descartes, Strasbourg 67084, France.
| | - Chi Ong
- Seqirus, 63 Poplar Rd, Parkville 3052, Victoria, Australia.
| | - Roland Marquet
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 rue René Descartes, Strasbourg 67084, France.
| | - Catherine Isel
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, 15 rue René Descartes, Strasbourg 67084, France.
- Unité de Génétique Moléculaire des Virus à ARN, Département de virologie, Institut Pasteur, Paris 75005, France.
| | - Steven Rockman
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute of Infection and Immunity, Parkville 3010, Victoria, Australia.
- Seqirus, 63 Poplar Rd, Parkville 3052, Victoria, Australia.
| | - Lorena Brown
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute of Infection and Immunity, Parkville 3010, Victoria, Australia.
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Isel C, Munier S, Naffakh N. Experimental Approaches to Study Genome Packaging of Influenza A Viruses. Viruses 2016; 8:v8080218. [PMID: 27517951 PMCID: PMC4997580 DOI: 10.3390/v8080218] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 07/26/2016] [Accepted: 08/01/2016] [Indexed: 11/16/2022] Open
Abstract
The genome of influenza A viruses (IAV) consists of eight single-stranded negative sense viral RNAs (vRNAs) encapsidated into viral ribonucleoproteins (vRNPs). It is now well established that genome packaging (i.e., the incorporation of a set of eight distinct vRNPs into budding viral particles), follows a specific pathway guided by segment-specific cis-acting packaging signals on each vRNA. However, the precise nature and function of the packaging signals, and the mechanisms underlying the assembly of vRNPs into sub-bundles in the cytoplasm and their selective packaging at the viral budding site, remain largely unknown. Here, we review the diverse and complementary methods currently being used to elucidate these aspects of the viral cycle. They range from conventional and competitive reverse genetics, single molecule imaging of vRNPs by fluorescence in situ hybridization (FISH) and high-resolution electron microscopy and tomography of budding viral particles, to solely in vitro approaches to investigate vRNA-vRNA interactions at the molecular level.
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Affiliation(s)
- Catherine Isel
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Moléculaire et Cellulaire (IBMC), 15 rue René Descartes, 67084 Strasbourg, France.
- Département de Virologie, Unité de Génétique Moléculaire des Virus à ARN, Institut Pasteur, 75015 Paris, France.
| | - Sandie Munier
- Département de Virologie, Unité de Génétique Moléculaire des Virus à ARN, Institut Pasteur, 75015 Paris, France.
- Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche 3569, 75016 Paris, France.
- Unité de Génétique Moléculaire des Virus à ARN, Sorbonne Paris Cité, Université Paris Diderot, 75013 Paris, France.
| | - Nadia Naffakh
- Département de Virologie, Unité de Génétique Moléculaire des Virus à ARN, Institut Pasteur, 75015 Paris, France.
- Centre National de la Recherche Scientifique (CNRS), Unité Mixte de Recherche 3569, 75016 Paris, France.
- Unité de Génétique Moléculaire des Virus à ARN, Sorbonne Paris Cité, Université Paris Diderot, 75013 Paris, France.
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46
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Pohl MO, Lanz C, Stertz S. Late stages of the influenza A virus replication cycle-a tight interplay between virus and host. J Gen Virol 2016; 97:2058-2072. [PMID: 27449792 DOI: 10.1099/jgv.0.000562] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After successful infection and replication of its genome in the nucleus of the host cell, influenza A virus faces several challenges before newly assembled viral particles can bud off from the plasma membrane, giving rise to a new infectious virus. The viral ribonucleoprotein (vRNP) complexes need to exit from the nucleus and be transported to the virus assembly sites at the plasma membrane. Moreover, they need to be bundled to ensure the incorporation of precisely one of each of the eight viral genome segments into newly formed viral particles. Similarly, viral envelope glycoproteins and other viral structural proteins need to be targeted to virus assembly sites for viral particles to form and bud off from the plasma membrane. During all these steps influenza A virus heavily relies on a tight interplay with its host, exploiting host-cell proteins for its own purposes. In this review, we summarize current knowledge on late stages of the influenza virus replication cycle, focusing on the role of host-cell proteins involved in this process.
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Affiliation(s)
- Marie O Pohl
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
| | - Caroline Lanz
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
| | - Silke Stertz
- Institute of Medical Virology, University of Zurich, 8057 Zurich, Switzerland
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47
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Kobayashi Y, Dadonaite B, van Doremalen N, Suzuki Y, Barclay WS, Pybus OG. Computational and molecular analysis of conserved influenza A virus RNA secondary structures involved in infectious virion production. RNA Biol 2016; 13:883-94. [PMID: 27399914 DOI: 10.1080/15476286.2016.1208331] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
As well as encoding viral proteins, genomes of RNA viruses harbor secondary and tertiary RNA structures that have been associated with functions essential for successful replication and propagation. Here, we identified stem-loop structures that are extremely conserved among 1,884 M segment sequences of influenza A virus (IAV) strains from various subtypes and host species using computational and evolutionary methods. These structures were predicted within the 3' and 5' ends of the coding regions of M1 and M2, respectively, where packaging signals have been previously proposed to exist. These signals are thought to be required for the incorporation of a single copy of 8 different negative-strand RNA segments (vRNAs) into an IAV particle. To directly test the functionality of conserved stem-loop structures, we undertook reverse genetic experiments to introduce synonymous mutations designed to disrupt secondary structures predicted at 3 locations and found them to attenuate infectivity of recombinant virus. In one mutant, predicted to disrupt stem loop structure at nucleotide positions 219-240, attenuation was more evident at increased temperature and was accompanied by an increase in the production of defective virus particles. Our results suggest that the conserved secondary structures predicted in the M segment are involved in the production of infectious viral particles during IAV replication.
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Affiliation(s)
- Yuki Kobayashi
- a Nihon University Veterinary Research Center , Fujisawa , Kanagawa , Japan.,b Department of Zoology , University of Oxford , Oxford , UK
| | - Bernadeta Dadonaite
- c Section of Virology, Department of Medicine, Imperial College London , London , UK
| | - Neeltje van Doremalen
- c Section of Virology, Department of Medicine, Imperial College London , London , UK.,d Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health , Hamilton , MT , USA
| | - Yoshiyuki Suzuki
- e Graduate School of Natural Sciences, Nagoya City University , Nagoya , Japan
| | - Wendy S Barclay
- c Section of Virology, Department of Medicine, Imperial College London , London , UK
| | - Oliver G Pybus
- b Department of Zoology , University of Oxford , Oxford , UK
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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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Nogales A, Baker SF, Domm W, Martínez-Sobrido L. Development and applications of single-cycle infectious influenza A virus (sciIAV). Virus Res 2016; 216:26-40. [PMID: 26220478 PMCID: PMC4728073 DOI: 10.1016/j.virusres.2015.07.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2015] [Revised: 07/05/2015] [Accepted: 07/13/2015] [Indexed: 02/06/2023]
Abstract
The diverse host range, high transmissibility, and rapid evolution of influenza A viruses justify the importance of containing pathogenic viruses studied in the laboratory. Other than physically or mechanically changing influenza A virus containment procedures, modifying the virus to only replicate for a single round of infection similarly ensures safety and consequently decreases the level of biosafety containment required to study highly pathogenic members in the virus family. This biological containment is more ideal because it is less apt to computer, machine, or human error. With many necessary proteins that can be deleted, generation of single-cycle infectious influenza A viruses (sciIAV) can be achieved using a variety of approaches. Here, we review the recent burst in sciIAV generation and summarize the applications and findings on this important human pathogen using biocontained viral mimics.
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Affiliation(s)
- Aitor Nogales
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Steven F Baker
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - William Domm
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Luis Martínez-Sobrido
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States.
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Brunotte L, Beer M, Horie M, Schwemmle M. Chiropteran influenza viruses: flu from bats or a relic from the past? Curr Opin Virol 2016; 16:114-119. [PMID: 26947779 DOI: 10.1016/j.coviro.2016.02.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/18/2016] [Indexed: 01/31/2023]
Abstract
The identification of influenza A-like genomic sequences in bats suggests the existence of distinct lineages of chiropteran influenza viruses in South and Central America. These viruses share similarities with conventional influenza A viruses but lack the canonical receptor-binding property and neuraminidase function. The inability to isolate infectious bat influenza viruses impeded further studies, however, reverse genetic analysis provided new insights into the molecular biology of these viruses. In this review, we highlight the recent developments in the field of the newly discovered bat-derived influenza A-like viruses. We also discuss whether bats are a neglected natural reservoir of influenza viruses, the risk associated with bat influenza viruses for humans and whether these viruses originate from the pool of avian IAV or vice versa.
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Affiliation(s)
- Linda Brunotte
- Institute of Molecular Virology, University of Muenster, Germany.
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Germany
| | - Masayuki Horie
- Transboundary Animal Diseases Research Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Martin Schwemmle
- Institute of Virology, University Medical Center Freiburg, Germany
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