1
|
Kleiner VA, Fearns R. How does the polymerase of non-segmented negative strand RNA viruses commit to transcription or genome replication? J Virol 2024; 98:e0033224. [PMID: 39078194 PMCID: PMC11334523 DOI: 10.1128/jvi.00332-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024] Open
Abstract
The Mononegavirales, or non-segmented negative-sense RNA viruses (nsNSVs), includes significant human pathogens, such as respiratory syncytial virus, parainfluenza virus, measles virus, Ebola virus, and rabies virus. Although these viruses differ widely in their pathogenic properties, they are united by each having a genome consisting of a single strand of negative-sense RNA. Consistent with their shared genome structure, the nsNSVs have evolved similar ways to transcribe their genome into mRNAs and replicate it to produce new genomes. Importantly, both mRNA transcription and genome replication are performed by a single virus-encoded polymerase. A fundamental and intriguing question is: how does the nsNSV polymerase commit to being either an mRNA transcriptase or a replicase? The polymerase must become committed to one process or the other either before it interacts with the genome template or in its initial interactions with the promoter sequence at the 3´ end of the genomic RNA. This review examines the biochemical, molecular biology, and structural biology data regarding the first steps of transcription and RNA replication that have been gathered over several decades for different families of nsNSVs. These findings are discussed in relation to possible models that could explain how an nsNSV polymerase initiates and commits to either transcription or genome replication.
Collapse
Affiliation(s)
- Victoria A. Kleiner
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Rachel Fearns
- Department of Virology, Immunology & Microbiology, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| |
Collapse
|
2
|
Passchier TC, White JBR, Maskell DP, Byrne MJ, Ranson NA, Edwards TA, Barr JN. The cryoEM structure of the Hendra henipavirus nucleoprotein reveals insights into paramyxoviral nucleocapsid architectures. Sci Rep 2024; 14:14099. [PMID: 38890308 PMCID: PMC11189427 DOI: 10.1038/s41598-024-58243-z] [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: 12/07/2023] [Accepted: 03/27/2024] [Indexed: 06/20/2024] Open
Abstract
We report the first cryoEM structure of the Hendra henipavirus nucleoprotein in complex with RNA, at 3.5 Å resolution, derived from single particle analysis of a double homotetradecameric RNA-bound N protein ring assembly exhibiting D14 symmetry. The structure of the HeV N protein adopts the common bi-lobed paramyxoviral N protein fold; the N-terminal and C-terminal globular domains are bisected by an RNA binding cleft containing six RNA nucleotides and are flanked by the N-terminal and C-terminal arms, respectively. In common with other paramyxoviral nucleocapsids, the lateral interface between adjacent Ni and Ni+1 protomers involves electrostatic and hydrophobic interactions mediated primarily through the N-terminal arm and globular domains with minor contribution from the C-terminal arm. However, the HeV N multimeric assembly uniquely identifies an additional protomer-protomer contact between the Ni+1 N-terminus and Ni-1 C-terminal arm linker. The model presented here broadens the understanding of RNA-bound paramyxoviral nucleocapsid architectures and provides a platform for further insight into the molecular biology of HeV, as well as the development of antiviral interventions.
Collapse
Affiliation(s)
- Tim C Passchier
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
- Department of Biology, University of York, York, YO10 5DD, UK.
| | - Joshua B R White
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Daniel P Maskell
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Matthew J Byrne
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
- Exscientia, The Schrödinger Building Oxford Science Park, Oxford, OX4 4GE, UK
| | - Neil A Ranson
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Thomas A Edwards
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
- College of Biomedical Sciences, Larkin University, 18301 N Miami Avenue, Miami, FL, 33169, USA.
| | - John N Barr
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
| |
Collapse
|
3
|
Liu M, Liu Y, Song T, Yang L, Qi L, Zhang YZ, Wang Y, Shen QT. Three-dimensional architecture of ESCRT-III flat spirals on the membrane. Proc Natl Acad Sci U S A 2024; 121:e2319115121. [PMID: 38709931 PMCID: PMC11098116 DOI: 10.1073/pnas.2319115121] [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: 11/01/2023] [Accepted: 04/01/2024] [Indexed: 05/08/2024] Open
Abstract
The endosomal sorting complexes required for transport (ESCRTs) are responsible for membrane remodeling in many cellular processes, such as multivesicular body biogenesis, viral budding, and cytokinetic abscission. ESCRT-III, the most abundant ESCRT subunit, assembles into flat spirals as the primed state, essential to initiate membrane invagination. However, the three-dimensional architecture of ESCRT-III flat spirals remained vague for decades due to highly curved filaments with a small diameter and a single preferred orientation on the membrane. Here, we unveiled that yeast Snf7, a component of ESCRT-III, forms flat spirals on the lipid monolayers using cryogenic electron microscopy. We developed a geometry-constrained Euler angle-assigned reconstruction strategy and obtained moderate-resolution structures of Snf7 flat spirals with varying curvatures. Our analyses showed that Snf7 subunits recline on the membrane with N-terminal motifs α0 as anchors, adopt an open state with fused α2/3 helices, and bend α2/3 gradually from the outer to inner parts of flat spirals. In all, we provide the orientation and conformations of ESCRT-III flat spirals on the membrane and unveil the underlying assembly mechanism, which will serve as the initial step in understanding how ESCRTs drive membrane abscission.
Collapse
Affiliation(s)
- Mingdong Liu
- School of Life Sciences, Department of Chemical Biology, Southern University of Science and Technology, Shenzhen518055, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao266237, China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen518055, China
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| | - Yunhui Liu
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen518055, China
| | - Tiefeng Song
- College of Life Sciences, Zhejiang University, Hangzhou310058, China
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining314400, China
| | - Liuyan Yang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao266237, China
| | - Lei Qi
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao266237, China
- Biomedical Research Center for Structural Analysis, Shandong University, Jinan250012, China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Qingdao266237, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou310058, China
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining314400, China
| | - Qing-Tao Shen
- School of Life Sciences, Department of Chemical Biology, Southern University of Science and Technology, Shenzhen518055, China
- Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao266237, China
- Institute for Biological Electron Microscopy, Southern University of Science and Technology, Shenzhen518055, China
- iHuman Institute and School of Life Science and Technology, ShanghaiTech University, Shanghai201210, China
| |
Collapse
|
4
|
Whitehead JD, Decool H, Leyrat C, Carrique L, Fix J, Eléouët JF, Galloux M, Renner M. Structure of the N-RNA/P interface indicates mode of L/P recruitment to the nucleocapsid of human metapneumovirus. Nat Commun 2023; 14:7627. [PMID: 37993464 PMCID: PMC10665349 DOI: 10.1038/s41467-023-43434-5] [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: 06/29/2023] [Accepted: 11/08/2023] [Indexed: 11/24/2023] Open
Abstract
Human metapneumovirus (HMPV) is a major cause of respiratory illness in young children. The HMPV polymerase (L) binds an obligate cofactor, the phosphoprotein (P). During replication and transcription, the L/P complex traverses the viral RNA genome, which is encapsidated within nucleoproteins (N). An essential interaction between N and a C-terminal region of P tethers the L/P polymerase to the template. This N-P interaction is also involved in the formation of cytoplasmic viral factories in infected cells, called inclusion bodies. To define how the polymerase component P recognizes N-encapsidated RNA (N-RNA) we employed cryogenic electron microscopy (cryo-EM) and molecular dynamics simulations, coupled to activity assays and imaging of inclusion bodies in cells. We report a 2.9 Å resolution structure of a triple-complex between multimeric N, bound to both RNA and the C-terminal region of P. Furthermore, we also present cryo-EM structures of assembled N in different oligomeric states, highlighting the plasticity of N. Combined with our functional assays, these structural data delineate in molecular detail how P attaches to N-RNA whilst retaining substantial conformational dynamics. Moreover, the N-RNA-P triple complex structure provides a molecular blueprint for the design of therapeutics to potentially disrupt the attachment of L/P to its template.
Collapse
Affiliation(s)
- Jack D Whitehead
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Hortense Decool
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | - Cédric Leyrat
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Loic Carrique
- Division of Structural Biology, The Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Jenna Fix
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France
| | | | - Marie Galloux
- Université Paris-Saclay, INRAE, UVSQ, VIM, 78350, Jouy-en-Josas, France.
| | - Max Renner
- Department of Chemistry, Umeå University, Umeå, Sweden.
- Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden.
| |
Collapse
|
5
|
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] [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.
Collapse
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.
| |
Collapse
|
6
|
Modrego A, Carlero D, Arranz R, Martín-Benito J. CryoEM of Viral Ribonucleoproteins and Nucleocapsids of Single-Stranded RNA Viruses. Viruses 2023; 15:v15030653. [PMID: 36992363 PMCID: PMC10053253 DOI: 10.3390/v15030653] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/05/2023] Open
Abstract
Single-stranded RNA viruses (ssRNAv) are characterized by their biological diversity and great adaptability to different hosts; traits which make them a major threat to human health due to their potential to cause zoonotic outbreaks. A detailed understanding of the mechanisms involved in viral proliferation is essential to address the challenges posed by these pathogens. Key to these processes are ribonucleoproteins (RNPs), the genome-containing RNA-protein complexes whose function is to carry out viral transcription and replication. Structural determination of RNPs can provide crucial information on the molecular mechanisms of these processes, paving the way for the development of new, more effective strategies to control and prevent the spread of ssRNAv diseases. In this scenario, cryogenic electron microscopy (cryoEM), relying on the technical and methodological revolution it has undergone in recent years, can provide invaluable help in elucidating how these macromolecular complexes are organized, packaged within the virion, or the functional implications of these structures. In this review, we summarize some of the most prominent achievements by cryoEM in the study of RNP and nucleocapsid structures in lipid-enveloped ssRNAv.
Collapse
Affiliation(s)
- Andrea Modrego
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049 Madrid, Spain
| | - Diego Carlero
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049 Madrid, Spain
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain
| | - Rocío Arranz
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049 Madrid, Spain
- Correspondence: (R.A.); (J.M.-B.)
| | - Jaime Martín-Benito
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología Consejo Superior de Investigaciones Científicas (CNB-CSIC), 28049 Madrid, Spain
- Correspondence: (R.A.); (J.M.-B.)
| |
Collapse
|
7
|
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] [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.
Collapse
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.
| |
Collapse
|
8
|
Abstract
Biological structures with helical symmetries of distinct twist, rise, and axial symmetry are abundant and span a wide range of organisms and functions. Performing de novo helical indexing remains challenging because of the steep learning curve involved in Fourier space layer lines. The unknown amount of out-of-plane tilt and the existence of multiple conformations of the helices further complicate indexing. In this work, we introduce a real-space indexing method that leverages the prior knowledge of the tilt and in-plane angles of the helical filaments/tubes, robust ab initio 3D reconstruction capabilities in single particle cryo-EM to obtain asymmetric reconstructions, and automatic indexing of helical parameters directly from the asymmetric density maps. We validated this approach using data from multiple helical structures of distinct helical symmetries, diameters, flexibility, data qualities, and heterogeneous states. The fully automated tool we introduce for real space indexing, HI3D, uses the 2D lattice in the autocorrelation of the cylindrical projection of a 3D density map to identify the helical symmetry. HI3D can often successfully determine the helical parameters of a suboptimal 3D density map, including ab initio single particle asymmetric reconstructions and sub-tomogram averages, with intermediate evidence that can also help assess the map quality. Furthermore, this open-source HI3D is usable independently as a Web application that can be accessed free of installation. With these methods, de novo helical indexing will be significantly more accessible to researchers investigating structures of helical filaments/tubes using cryo-EM.
Collapse
Affiliation(s)
- Chen Sun
- grid.169077.e0000 0004 1937 2197Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47907 USA
| | - Brenda Gonzalez
- grid.169077.e0000 0004 1937 2197Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47907 USA
| | - Wen Jiang
- grid.169077.e0000 0004 1937 2197Department of Biological Sciences, Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47907 USA
| |
Collapse
|
9
|
Dong X, Wang X, Xie M, Wu W, Chen Z. Structural Basis of Human Parainfluenza Virus 3 Unassembled Nucleoprotein in Complex with Its Viral Chaperone. J Virol 2022; 96:e0164821. [PMID: 34730394 PMCID: PMC8791282 DOI: 10.1128/jvi.01648-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/30/2021] [Indexed: 11/20/2022] Open
Abstract
Human parainfluenza virus 3 (HPIV3) belongs to the Paramyxoviridae, causing annual worldwide epidemics of respiratory diseases, especially in newborns and infants. The core components consist of just three viral proteins: nucleoprotein (N), phosphoprotein (P), and RNA polymerase (L), playing essential roles in replication and transcription of HPIV3 as well as other paramyxoviruses. Viral genome encapsidated by N is as a template and recognized by RNA-dependent RNA polymerase complex composed of L and P. The offspring RNA also needs to assemble with N to form nucleocapsids. The N is one of the most abundant viral proteins in infected cells and chaperoned in the RNA-free form (N0) by P before encapsidation. In this study, we presented the structure of unassembled HPIV3 N0 in complex with the N-terminal portion of the P, revealing the molecular details of the N0 and the conserved N0-P interaction. Combined with biological experiments, we showed that the P binds to the C-terminal domain of N0 mainly by hydrophobic interaction and maintains the unassembled conformation of N by interfering with the formation of N-RNA oligomers, which might be a target for drug development. Based on the complex structure, we developed a method to obtain the monomeric N0. Furthermore, we designed a P-derived fusion peptide with 10-fold higher affinity, which hijacked the N and interfered with the binding of the N to RNA significantly. Finally, we proposed a model of conformational transition of N from the unassembled state to the assembled state, which helped to further understand viral replication. IMPORTANCE Human parainfluenza virus 3 (HPIV3) causes annual epidemics of respiratory diseases, especially in newborns and infants. For the replication of HPIV3 and other paramyxoviruses, only three viral proteins are required: phosphoprotein (P), RNA polymerase (L), and nucleoprotein (N). Here, we report the crystal structure of the complex of N and its chaperone P. We describe in detail how P acts as a chaperone to maintain the unassembled conformation of N. Our analysis indicated that the interaction between P and N is conserved and mediated by hydrophobicity, which can be used as a target for drug development. We obtained a high-affinity P-derived peptide inhibitor, specifically targeted N, and greatly interfered with the binding of the N to RNA, thereby inhibiting viral encapsidation and replication. In summary, our results provide new insights into the paramyxovirus genome replication and nucleocapsid assembly and lay the basis for drug development.
Collapse
Affiliation(s)
- Xiaofei Dong
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xue Wang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Mengjia Xie
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Wei Wu
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, China
| |
Collapse
|
10
|
Insights into Paramyxovirus Nucleocapsids from Diverse Assemblies. Viruses 2021; 13:v13122479. [PMID: 34960748 PMCID: PMC8705878 DOI: 10.3390/v13122479] [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: 10/29/2021] [Revised: 11/29/2021] [Accepted: 12/07/2021] [Indexed: 12/02/2022] Open
Abstract
All paramyxoviruses, which include the mumps virus, measles virus, Nipah virus, Newcastle disease virus, and Sendai virus, have non-segmented single-stranded negative-sense RNA genomes. These RNA genomes are enwrapped throughout the viral life cycle by nucleoproteins, forming helical nucleocapsids. In addition to these helical structures, recombinant paramyxovirus nucleocapsids may occur in other assembly forms such as rings, clam-shaped structures, and double-headed nucleocapsids; the latter two are composed of two single-stranded helices packed in a back-to-back pattern. In all of these assemblies, the neighboring nucleoprotein protomers adopt the same domain-swapping mode via the N-terminal arm, C-terminal arm, and recently disclosed N-hole. An intrinsically disordered region in the C-terminal domain of the nucleoproteins, called the N-tail, plays an unexpected role in regulating the transition among the different assembly forms that occurs with other viral proteins, especially phosphoprotein. These structures, together with the helical nucleocapsids, significantly enrich the structural diversity of the paramyxovirus nucleocapsids and help explain the functions of these diverse assemblies, including RNA genome protection, transcription, and replication, as well as encapsulation.
Collapse
|
11
|
Kolakofsky D, Le Mercier P, Nishio M, Blackledge M, Crépin T, Ruigrok RWH. Sendai Virus and a Unified Model of Mononegavirus RNA Synthesis. Viruses 2021; 13:v13122466. [PMID: 34960735 PMCID: PMC8708023 DOI: 10.3390/v13122466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/06/2021] [Accepted: 12/07/2021] [Indexed: 12/20/2022] Open
Abstract
Vesicular stomatitis virus (VSV), the founding member of the mononegavirus order (Mononegavirales), was found to be a negative strand RNA virus in the 1960s, and since then the number of such viruses has continually increased with no end in sight. Sendai virus (SeV) was noted soon afterwards due to an outbreak of newborn pneumonitis in Japan whose putative agent was passed in mice, and nowadays this mouse virus is mainly the bane of animal houses and immunologists. However, SeV was important in the study of this class of viruses because, like flu, it grows to high titers in embryonated chicken eggs, facilitating the biochemical characterization of its infection and that of its nucleocapsid, which is very close to that of measles virus (MeV). This review and opinion piece follow SeV as more is known about how various mononegaviruses express their genetic information and carry out their RNA synthesis, and proposes a unified model based on what all MNV have in common.
Collapse
Affiliation(s)
- Daniel Kolakofsky
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, Medical School, University of Geneva, 1211 Geneva, Switzerland
- Correspondence: (D.K.); (R.W.H.R.)
| | - Philippe Le Mercier
- Swiss-Prot Group, Swiss Institute of Bioinformatics, School of Medicine, University of Geneva, 1211 Geneva, Switzerland;
| | - Machiko Nishio
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama 641-8509, Japan;
| | - Martin Blackledge
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, 38058 Grenoble, France; (M.B.); (T.C.)
| | - Thibaut Crépin
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, 38058 Grenoble, France; (M.B.); (T.C.)
| | - Rob W. H. Ruigrok
- Institut de Biologie Structurale (IBS), CEA, CNRS, Université Grenoble Alpes, 38058 Grenoble, France; (M.B.); (T.C.)
- Correspondence: (D.K.); (R.W.H.R.)
| |
Collapse
|
12
|
The Nucleocapsid of Paramyxoviruses: Structure and Function of an Encapsidated Template. Viruses 2021; 13:v13122465. [PMID: 34960734 PMCID: PMC8708338 DOI: 10.3390/v13122465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 01/28/2023] Open
Abstract
Viruses of the Paramyxoviridae family share a common and complex molecular machinery for transcribing and replicating their genomes. Their non-segmented, negative-strand RNA genome is encased in a tight homopolymer of viral nucleoproteins (N). This ribonucleoprotein complex, termed a nucleocapsid, is the template of the viral polymerase complex made of the large protein (L) and its co-factor, the phosphoprotein (P). This review summarizes the current knowledge on several aspects of paramyxovirus transcription and replication, including structural and functional data on (1) the architecture of the nucleocapsid (structure of the nucleoprotein, interprotomer contacts, interaction with RNA, and organization of the disordered C-terminal tail of N), (2) the encapsidation of the genomic RNAs (structure of the nucleoprotein in complex with its chaperon P and kinetics of RNA encapsidation in vitro), and (3) the use of the nucleocapsid as a template for the polymerase complex (release of the encased RNA and interaction network allowing the progress of the polymerase complex). Finally, this review presents models of paramyxovirus transcription and replication.
Collapse
|
13
|
Structural Analysis of the Menangle Virus P Protein Reveals a Soft Boundary between Ordered and Disordered Regions. Viruses 2021; 13:v13091737. [PMID: 34578318 PMCID: PMC8472933 DOI: 10.3390/v13091737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 11/17/2022] Open
Abstract
The paramyxoviral phosphoprotein (P protein) is the non-catalytic subunit of the viral RNA polymerase, and coordinates many of the molecular interactions required for RNA synthesis. All paramyxoviral P proteins oligomerize via a centrally located coiled-coil that is connected to a downstream binding domain by a dynamic linker. The C-terminal region of the P protein coordinates interactions between the catalytic subunit of the polymerase, and the viral nucleocapsid housing the genomic RNA. The inherent flexibility of the linker is believed to facilitate polymerase translocation. Here we report biophysical and structural characterization of the C-terminal region of the P protein from Menangle virus (MenV), a bat-borne paramyxovirus with zoonotic potential. The MenV P protein is tetrameric but can dissociate into dimers at sub-micromolar protein concentrations. The linker is globally disordered and can be modeled effectively as a worm-like chain. However, NMR analysis suggests very weak local preferences for alpha-helical and extended beta conformation exist within the linker. At the interface between the disordered linker and the structured C-terminal binding domain, a gradual disorder-to-order transition occurs, with X-ray crystallographic analysis revealing a dynamic interfacial structure that wraps the surface of the binding domain.
Collapse
|
14
|
Ker DS, Jenkins HT, Greive SJ, Antson AA. CryoEM structure of the Nipah virus nucleocapsid assembly. PLoS Pathog 2021; 17:e1009740. [PMID: 34270629 PMCID: PMC8318291 DOI: 10.1371/journal.ppat.1009740] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/28/2021] [Accepted: 06/22/2021] [Indexed: 11/18/2022] Open
Abstract
Nipah and its close relative Hendra are highly pathogenic zoonotic viruses, storing their ssRNA genome in a helical nucleocapsid assembly formed by the N protein, a major viral immunogen. Here, we report the first cryoEM structure for a Henipavirus RNA-bound nucleocapsid assembly, at 3.5 Å resolution. The helical assembly is stabilised by previously undefined N- and C-terminal segments, contributing to subunit-subunit interactions. RNA is wrapped around the nucleocapsid protein assembly with a periodicity of six nucleotides per protomer, in the “3-bases-in, 3-bases-out” conformation, with protein plasticity enabling non-sequence specific interactions. The structure reveals commonalities in RNA binding pockets and in the conformation of bound RNA, not only with members of the Paramyxoviridae family, but also with the evolutionarily distant Filoviridae Ebola virus. Significant structural differences with other Paramyxoviridae members are also observed, particularly in the position and length of the exposed α-helix, residues 123–139, which may serve as a valuable epitope for surveillance and diagnostics. Nipah virus is a highly pathogenic RNA virus which, along with the closely related Hendra virus, emerged relatively recently. Due to ~40% mortality rate and evidence of animal-to-human as well as human-to-human transmission, development of antivirals against the Nipah and henipaviral disease is particularly urgent. In common with other single-stranded RNA viruses, including Ebola and coronaviruses, the nucleocapsid assembly of the Nipah virus safeguards the viral genome, protecting it from degradation and facilitating its encapsidation and storage inside the virion. Here, we used cryo-electron microscopy to determine accurate three-dimensional structure for several different assemblies of the Nipah virus nucleocapsid protein, in particular a detailed structure for the complex of this protein with RNA. This structural information is important for understanding detailed molecular interactions driving and stabilizing the nucleocapsid assembly formation that are of fundamental importance for understanding similar processes in a large group of ssRNA viruses. Apart from highlighting structural similarities and differences with nucleocapsid proteins of other viruses of the Paramyxoviridae family, these data will inform the development of new antiviral approaches for the henipaviruses.
Collapse
Affiliation(s)
- De-Sheng Ker
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
| | - Huw T. Jenkins
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
| | - Sandra J. Greive
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
| | - Alfred A. Antson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, United Kingdom
- * E-mail:
| |
Collapse
|
15
|
Structural plasticity of mumps virus nucleocapsids with cryo-EM structures. Commun Biol 2021; 4:833. [PMID: 34215847 PMCID: PMC8253768 DOI: 10.1038/s42003-021-02362-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 06/11/2021] [Indexed: 11/08/2022] Open
Abstract
Mumps virus (MuV) is a highly contagious human pathogen and frequently causes worldwide outbreaks despite available vaccines. Similar to other mononegaviruses such as Ebola and rabies, MuV uses a single-stranded negative-sense RNA as its genome, which is enwrapped by viral nucleoproteins into the helical nucleocapsid. The nucleocapsid acts as a scaffold for genome condensation and as a template for RNA replication and transcription. Conformational changes in the MuV nucleocapsid are required to switch between different activities, but the underlying mechanism remains elusive due to the absence of high-resolution structures. Here, we report two MuV nucleoprotein-RNA rings with 13 and 14 protomers, one stacked-ring filament and two nucleocapsids with distinct helical pitches, in dense and hyperdense states, at near-atomic resolutions using cryo-electron microscopy. Structural analysis of these in vitro assemblies indicates that the C-terminal tail of MuV nucleoprotein likely regulates the assembly of helical nucleocapsids, and the C-terminal arm may be relevant for the transition between the dense and hyperdense states of helical nucleocapsids. Our results provide the molecular mechanism for structural plasticity among different MuV nucleocapsids and create a possible link between structural plasticity and genome condensation. Shan et al. describes the high-resolution structures of Nucleoprotein in two different oligomeric states and four different higher-order helical structures. They further describe the structural rearrangements required to transition between the different helical assemblies obtained, highlighting the basis for structural plasticity among different MuV nucleocapsids.
Collapse
|