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Hover S, Barr JN, Fontana J. Insights into the structure of RNPs from segmented negative-sense RNA viruses. Structure 2024; 32:1027-1028. [PMID: 39121836 DOI: 10.1016/j.str.2024.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2024] [Revised: 07/10/2024] [Accepted: 07/10/2024] [Indexed: 08/12/2024]
Abstract
The genome of segmented negative-sense single-stranded RNA viruses, such as influenza virus and bunyaviruses, is coated by viral nucleoproteins (NPs), forming a ribonucleoprotein (RNP). In this issue of Structure, Dick et al.1 expand our knowledge on the RNPs of these viruses by solving the structures of Thogoto virus NP and RNP.
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Affiliation(s)
- Samantha Hover
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - John N Barr
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - Juan Fontana
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK; Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
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Sabsay KR, te Velthuis AJW. Negative and ambisense RNA virus ribonucleocapsids: more than protective armor. Microbiol Mol Biol Rev 2023; 87:e0008223. [PMID: 37750733 PMCID: PMC10732063 DOI: 10.1128/mmbr.00082-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023] Open
Abstract
SUMMARYNegative and ambisense RNA viruses are the causative agents of important human diseases such as influenza, measles, Lassa fever, and Ebola hemorrhagic fever. The viral genome of these RNA viruses consists of one or more single-stranded RNA molecules that are encapsidated by viral nucleocapsid proteins to form a ribonucleoprotein complex (RNP). This RNP acts as protection, as a scaffold for RNA folding, and as the context for viral replication and transcription by a viral RNA polymerase. However, the roles of the viral nucleoproteins extend beyond these functions during the viral infection cycle. Recent advances in structural biology techniques and analysis methods have provided new insights into the formation, function, dynamics, and evolution of negative sense virus nucleocapsid proteins, as well as the role that they play in host innate immune responses against viral infection. In this review, we discuss the various roles of nucleocapsid proteins, both in the context of RNPs and in RNA-free states, as well as the open questions that remain.
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Affiliation(s)
- Kimberly R. Sabsay
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Aartjan J. W. te Velthuis
- Lewis Thomas Laboratory, Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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Chenavier F, Estrozi LF, Teulon JM, Zarkadas E, Freslon LL, Pellequer JL, Ruigrok RW, Schoehn G, Ballandras-Colas A, Crépin T. Cryo-EM structure of influenza helical nucleocapsid reveals NP-NP and NP-RNA interactions as a model for the genome encapsidation. SCIENCE ADVANCES 2023; 9:eadj9974. [PMID: 38100595 PMCID: PMC10848707 DOI: 10.1126/sciadv.adj9974] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/16/2023] [Indexed: 12/17/2023]
Abstract
Influenza virus genome encapsidation is essential for the formation of a helical viral ribonucleoprotein (vRNP) complex composed of nucleoproteins (NP), the trimeric polymerase, and the viral genome. Although low-resolution vRNP structures are available, it remains unclear how the viral RNA is encapsidated and how NPs assemble into the helical filament specific of influenza vRNPs. In this study, we established a biological tool, the RNP-like particles assembled from recombinant influenza A virus NP and synthetic RNA, and we present the first subnanometric cryo-electron microscopy structure of the helical NP-RNA complex (8.7 to 5.3 Å). The helical RNP-like structure reveals a parallel double-stranded conformation, allowing the visualization of NP-NP and NP-RNA interactions. The RNA, located at the interface of neighboring NP protomers, interacts with conserved residues previously described as essential for the NP-RNA interaction. The NP undergoes conformational changes to enable RNA binding and helix formation. Together, our findings provide relevant insights for understanding the mechanism for influenza genome encapsidation.
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Affiliation(s)
| | | | | | | | | | | | | | - Guy Schoehn
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France
| | | | - Thibaut Crépin
- Univ. Grenoble Alpes, CNRS, CEA, IBS, F-38000, Grenoble, France
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Schoehn G, Chenavier F, Crépin T. Advances in Structural Virology via Cryo-EM in 2022. Viruses 2023; 15:1315. [PMID: 37376615 DOI: 10.3390/v15061315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 05/30/2023] [Indexed: 06/29/2023] Open
Abstract
In recent years, cryo-electron microscopy (cryo-EM) has emerged as an important standalone technique within structural biology [...].
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Affiliation(s)
- Guy Schoehn
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, 38058 Grenoble, France
| | - Florian Chenavier
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, 38058 Grenoble, France
| | - Thibaut Crépin
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, 38058 Grenoble, France
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