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Gonnin L, Desfosses A, Bacia-Verloop M, Chevret D, Galloux M, Éléouët JF, Gutsche I. Structural landscape of the respiratory syncytial virus nucleocapsids. Nat Commun 2023; 14:5732. [PMID: 37714861 PMCID: PMC10504348 DOI: 10.1038/s41467-023-41439-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/01/2023] [Indexed: 09/17/2023] Open
Abstract
Human Respiratory Syncytial Virus (HRSV) is a prevalent cause of severe respiratory infections in children and the elderly. The helical HRSV nucleocapsid is a template for the viral RNA synthesis and a scaffold for the virion assembly. This cryo-electron microscopy analysis reveals the non-canonical arrangement of the HRSV nucleocapsid helix, composed of 16 nucleoproteins per asymmetric unit, and the resulting systematic variations in the RNA accessibility. We demonstrate that this unique helical symmetry originates from longitudinal interactions by the C-terminal arm of the HRSV nucleoprotein. We explore the polymorphism of the nucleocapsid-like assemblies, report five structures of the full-length particles and two alternative arrangements formed by a C-terminally truncated nucleoprotein mutant, and demonstrate the functional importance of the identified longitudinal interfaces. We put all these findings in the context of the HRSV RNA synthesis machinery and delineate the structural basis for its further investigation.
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Affiliation(s)
- Lorène Gonnin
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France
- VIM, Paris-Saclay University, INRAE, 78350, Jouy-en-Josas, France
| | - Ambroise Desfosses
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France.
| | - Maria Bacia-Verloop
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France
| | - Didier Chevret
- VIM, Paris-Saclay University, INRAE, 78350, Jouy-en-Josas, France
| | - Marie Galloux
- VIM, Paris-Saclay University, INRAE, 78350, Jouy-en-Josas, France
| | | | - Irina Gutsche
- Institut de Biologie Structurale, Univ Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des martyrs, F-38044, Grenoble, France.
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Gonnin L, Richard CA, Gutsche I, Chevret D, Troussier J, Vasseur JJ, Debart F, Eléouët JF, Galloux M. Importance of RNA length for in vitro encapsidation by the nucleoprotein of human Respiratory Syncytial Virus. J Biol Chem 2022; 298:102337. [PMID: 35931116 PMCID: PMC9436823 DOI: 10.1016/j.jbc.2022.102337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/29/2022] Open
Abstract
Respiratory syncytial virus has a negative-sense single-stranded RNA genome constitutively encapsidated by the viral nucleoprotein N, forming a helical nucleocapsid which is the template for viral transcription and replication by the viral polymerase L. Recruitment of L onto the nucleocapsid depends on the viral phosphoprotein P, which is an essential L cofactor. A prerequisite for genome and antigenome encapsidation is the presence of the monomeric, RNA-free, neosynthesized N protein, named N0. Stabilization of N0 depends on the binding of the N-terminal residues of P to its surface, which prevents N oligomerization. However, the mechanism involved in the transition from N0-P to nucleocapsid assembly, and thus in the specificity of viral genome encapsidation, is still unknown. Furthermore, the specific role of N oligomerization and RNA in the morphogenesis of viral factories, where viral transcription and replication occur, have not been elucidated although the interaction between P and N complexed to RNA has been shown to be responsible for this process. Here, using a chimeric protein comprising N and the first 40 N-terminal residues of P, we succeeded in purifying a recombinant N0-like protein competent for RNA encapsidation in vitro. Our results showed the importance of RNA length for stable encapsidation and revealed that the nature of the 5′ end of RNA does not explain the specificity of encapsidation. Finally, we showed that RNA encapsidation is crucial for the in vitro reconstitution of pseudo-viral factories. Together, our findings provide insight into respiratory syncytial virus viral genome encapsidation specificity.
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Affiliation(s)
- Lorène Gonnin
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | | | - Irina Gutsche
- University of Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Didier Chevret
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Joris Troussier
- IBMM, Université de Montpellier, ENSCM, CNRS, UMR 5247, Montpellier, France
| | | | - Françoise Debart
- IBMM, Université de Montpellier, ENSCM, CNRS, UMR 5247, Montpellier, France
| | | | - Marie Galloux
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France.
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Descamps D, Peres de Oliveira A, Gonnin L, Madrières S, Fix J, Drajac C, Marquant Q, Bouguyon E, Pietralunga V, Iha H, Morais Ventura A, Tangy F, Vidalain PO, Eléouët JF, Galloux M. Depletion of TAX1BP1 Amplifies Innate Immune Responses during Respiratory Syncytial Virus Infection. J Virol 2021; 95:e0091221. [PMID: 34431698 PMCID: PMC8549506 DOI: 10.1128/jvi.00912-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/20/2021] [Indexed: 12/15/2022] Open
Abstract
Respiratory syncytial virus (RSV) is the main cause of acute respiratory infections in young children and also has a major impact on the elderly and immunocompromised people. In the absence of a vaccine or efficient treatment, a better understanding of RSV interactions with the host antiviral response during infection is needed. Previous studies revealed that cytoplasmic inclusion bodies (IBs), where viral replication and transcription occur, could play a major role in the control of innate immunity during infection by recruiting cellular proteins involved in the host antiviral response. We recently showed that the morphogenesis of IBs relies on a liquid-liquid-phase separation mechanism depending on the interaction between viral nucleoprotein (N) and phosphoprotein (P). These scaffold proteins are expected to play a central role in the recruitment of cellular proteins to IBs. Here, we performed a yeast two-hybrid screen using RSV N protein as bait and identified the cellular protein TAX1BP1 as a potential partner of this viral protein. This interaction was validated by pulldown and immunoprecipitation assays. We showed that TAX1BP1 suppression has only a limited impact on RSV infection in cell cultures. However, RSV replication is decreased in TAX1BP1-deficient (TAX1BP1 knockout [TAX1BP1KO]) mice, whereas the production of inflammatory and antiviral cytokines is enhanced. In vitro infection of wild-type or TAX1BP1KO alveolar macrophages confirmed that the innate immune response to RSV infection is enhanced in the absence of TAX1BP1. Altogether, our results suggest that RSV could hijack TAX1BP1 to restrain the host immune response during infection. IMPORTANCE Respiratory syncytial virus (RSV), which is the leading cause of lower respiratory tract illness in infants, remains a medical problem in the absence of a vaccine or efficient treatment. This virus is also recognized as a main pathogen in the elderly and immunocompromised people, and the occurrence of coinfections (with other respiratory viruses and bacteria) amplifies the risks of developing respiratory distress. In this context, a better understanding of the pathogenesis associated with viral respiratory infections, which depends on both viral replication and the host immune response, is needed. The present study reveals that the cellular protein TAX1BP1, which interacts with the RSV nucleoprotein N, participates in the control of the innate immune response during RSV infection, suggesting that the N-TAX1BP1 interaction represents a new target for the development of antivirals.
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Affiliation(s)
| | - Andressa Peres de Oliveira
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Lorène Gonnin
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Sarah Madrières
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Jenna Fix
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Carole Drajac
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Quentin Marquant
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | - Edwige Bouguyon
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
| | | | - Hidekatsu Iha
- Department of Infectious Diseases, Faculty of Medicine, Oita University Idaiga-oka, Hasama Yufu, Japan
| | - Armando Morais Ventura
- Departamento de Microbiologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, Brazil
| | - Frédéric Tangy
- Unité de Génomique Virale et Vaccination, Institut Pasteur, CNRS UMR-3569, Paris, France
| | - Pierre-Olivier Vidalain
- Unité de Génomique Virale et Vaccination, Institut Pasteur, CNRS UMR-3569, Paris, France
- CIRI, Centre International de Recherche en Infectiologie, Université Lyon, Inserm, U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Lyon, France
| | | | - Marie Galloux
- Université Paris-Saclay, INRAE, UVSQ, VIM, Jouy-en-Josas, France
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