1
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Sung PY, Phelan JE, Luo D, Kulasegaran-Shylini R, Bohn P, Smyth RP, Roy P. Recruitment of multi-segment genomic RNAs by Bluetongue virus requires a preformed RNA network. Nucleic Acids Res 2024; 52:8500-8514. [PMID: 38769067 DOI: 10.1093/nar/gkae404] [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: 12/20/2023] [Revised: 04/22/2024] [Accepted: 05/01/2024] [Indexed: 05/22/2024] Open
Abstract
How do segmented RNA viruses correctly recruit their genome has yet to be clarified. Bluetongue virus is a double-stranded RNA virus with 10 segments of different sizes, but it assembles its genome in single-stranded form through a series of specific RNA-RNA interactions prior to packaging. In this study, we determined the structure of each BTV transcript, individually and in different combinations, using 2'-hydroxyl acylation analysed by primer extension and mutational profiling (SHAPE-MaP). SHAPE-MaP identified RNA structural changes during complex formation and putative RNA-RNA interaction sites. Our data also revealed a core RNA-complex of smaller segments which serves as the foundation ('anchor') for the assembly of a complete network composed of ten ssRNA segments. The same order of core RNA complex formation was identified in cells transfected with viral RNAs. No viral protein was required for these assembly reactions. Further, substitution mutations in the interacting bases within the core assemblies, altered subsequent segment addition and affected virus replication. These data identify a wholly RNA driven reaction that may offer novel opportunities for designed attenuation or antiviral therapeutics.
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Affiliation(s)
- Po-Yu Sung
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Jody E Phelan
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Dongsheng Luo
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Patrick Bohn
- Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
| | - Redmond P Smyth
- Helmholtz Institute for RNA-based Infection Research (HIRI), Würzburg, Germany
- Faculty of Medicine, University of Würzburg, Würzburg, Germany
| | - Polly Roy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
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2
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Xia X, Sung PY, Martynowycz MW, Gonen T, Roy P, Zhou ZH. RNA genome packaging and capsid assembly of bluetongue virus visualized in host cells. Cell 2024; 187:2236-2249.e17. [PMID: 38614100 PMCID: PMC11182334 DOI: 10.1016/j.cell.2024.03.007] [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: 01/17/2023] [Revised: 10/18/2023] [Accepted: 03/07/2024] [Indexed: 04/15/2024]
Abstract
Unlike those of double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), and ssRNA viruses, the mechanism of genome packaging of dsRNA viruses is poorly understood. Here, we combined the techniques of high-resolution cryoelectron microscopy (cryo-EM), cellular cryoelectron tomography (cryo-ET), and structure-guided mutagenesis to investigate genome packaging and capsid assembly of bluetongue virus (BTV), a member of the Reoviridae family of dsRNA viruses. A total of eleven assembly states of BTV capsid were captured, with resolutions up to 2.8 Å, with most visualized in the host cytoplasm. ATPase VP6 was found underneath the vertices of capsid shell protein VP3 as an RNA-harboring pentamer, facilitating RNA packaging. RNA packaging expands the VP3 shell, which then engages middle- and outer-layer proteins to generate infectious virions. These revealed "duality" characteristics of the BTV assembly mechanism reconcile previous contradictory co-assembly and core-filling models and provide insights into the mysterious RNA packaging and capsid assembly of Reoviridae members and beyond.
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Affiliation(s)
- Xian Xia
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Po-Yu Sung
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Michael W Martynowycz
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Tamir Gonen
- Howard Hughes Medical Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Polly Roy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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3
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Vetter J, Papa G, Tobler K, Rodriguez JM, Kley M, Myers M, Wiesendanger M, Schraner EM, Luque D, Burrone OR, Fraefel C, Eichwald C. The recruitment of TRiC chaperonin in rotavirus viroplasms correlates with virus replication. mBio 2024; 15:e0049924. [PMID: 38470055 PMCID: PMC11005421 DOI: 10.1128/mbio.00499-24] [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] [Received: 02/19/2024] [Accepted: 02/22/2024] [Indexed: 03/13/2024] Open
Abstract
Rotavirus (RV) replication takes place in the viroplasms, cytosolic inclusions that allow the synthesis of virus genome segments and their encapsidation in the core shell, followed by the addition of the second layer of the virion. The viroplasms are composed of several viral proteins, including NSP5, which serves as the main building block. Microtubules, lipid droplets, and miRNA-7 are among the host components recruited in viroplasms. We investigated the interaction between RV proteins and host components of the viroplasms by performing a pull-down assay of lysates from RV-infected cells expressing NSP5-BiolD2. Subsequent tandem mass spectrometry identified all eight subunits of the tailless complex polypeptide I ring complex (TRiC), a cellular chaperonin responsible for folding at least 10% of the cytosolic proteins. Our confirmed findings reveal that TRiC is brought into viroplasms and wraps around newly formed double-layered particles. Chemical inhibition of TRiC and silencing of its subunits drastically reduced virus progeny production. Through direct RNA sequencing, we show that TRiC is critical for RV replication by controlling dsRNA genome segment synthesis, particularly negative-sense single-stranded RNA. Importantly, cryo-electron microscopy analysis shows that TRiC inhibition results in defective virus particles lacking genome segments and polymerase complex (VP1/VP3). Moreover, TRiC associates with VP2 and NSP5 but not with VP1. Also, VP2 is shown to be essential for recruiting TRiC in viroplasms and preserving their globular morphology. This study highlights the essential role of TRiC in viroplasm formation and in facilitating virion assembly during the RV life cycle. IMPORTANCE The replication of rotavirus takes place in cytosolic inclusions termed viroplasms. In these inclusions, the distinct 11 double-stranded RNA genome segments are co-packaged to complete a genome in newly generated virus particles. In this study, we show for the first time that the tailless complex polypeptide I ring complex (TRiC), a cellular chaperonin responsible for the folding of at least 10% of the cytosolic proteins, is a component of viroplasms and is required for the synthesis of the viral negative-sense single-stranded RNA. Specifically, TRiC associates with NSP5 and VP2, the cofactor involved in RNA replication. Our study adds a new component to the current model of rotavirus replication, where TRiC is recruited to viroplasms to assist replication.
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Affiliation(s)
- Janine Vetter
- Institute of Virology, University of Zurich, Zurich, Switzerland
| | - Guido Papa
- Molecular Immunology Lab, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Kurt Tobler
- Institute of Virology, University of Zurich, Zurich, Switzerland
| | - Javier M. Rodriguez
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología/CSIC, Cantoblanco, Madrid, Spain
| | - Manuel Kley
- Institute of Virology, University of Zurich, Zurich, Switzerland
| | - Michael Myers
- Proteomics Lab, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Mahesa Wiesendanger
- Institute of Virology, University of Zurich, Zurich, Switzerland
- Institute of Veterinary Anatomy, University of Zurich, Zurich, Switzerland
| | - Elisabeth M. Schraner
- Institute of Virology, University of Zurich, Zurich, Switzerland
- Institute of Veterinary Anatomy, University of Zurich, Zurich, Switzerland
| | - Daniel Luque
- School of Biomedical Sciences, The University of New South Wales, Sydney, New South Wales, Australia
- Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, New South Wales, Australia
| | - Oscar R. Burrone
- Molecular Immunology Lab, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - Cornel Fraefel
- Institute of Virology, University of Zurich, Zurich, Switzerland
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4
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Wang H, Marucci G, Munke A, Hassan MM, Lalle M, Okamoto K. High-resolution comparative atomic structures of two Giardiavirus prototypes infecting G. duodenalis parasite. PLoS Pathog 2024; 20:e1012140. [PMID: 38598600 PMCID: PMC11081498 DOI: 10.1371/journal.ppat.1012140] [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: 11/08/2023] [Revised: 05/09/2024] [Accepted: 03/21/2024] [Indexed: 04/12/2024] Open
Abstract
The Giardia lamblia virus (GLV) is a non-enveloped icosahedral dsRNA and endosymbiont virus that infects the zoonotic protozoan parasite Giardia duodenalis (syn. G. lamblia, G. intestinalis), which is a pathogen of mammals, including humans. Elucidating the transmission mechanism of GLV is crucial for gaining an in-depth understanding of the virulence of the virus in G. duodenalis. GLV belongs to the family Totiviridae, which infects yeast and protozoa intracellularly; however, it also transmits extracellularly, similar to the phylogenetically, distantly related toti-like viruses that infect multicellular hosts. The GLV capsid structure is extensively involved in the longstanding discussion concerning extracellular transmission in Totiviridae and toti-like viruses. Hence, this study constructed the first high-resolution comparative atomic models of two GLV strains, namely GLV-HP and GLV-CAT, which showed different intracellular localization and virulence phenotypes, using cryogenic electron microscopy single-particle analysis. The atomic models of the GLV capsids presented swapped C-terminal extensions, extra surface loops, and a lack of cap-snatching pockets, similar to those of toti-like viruses. However, their open pores and absence of the extra crown protein resemble those of other yeast and protozoan Totiviridae viruses, demonstrating the essential structures for extracellular cell-to-cell transmission. The structural comparison between GLV-HP and GLV-CAT indicates the first evidence of critical structural motifs for the transmission and virulence of GLV in G. duodenalis.
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Affiliation(s)
- Han Wang
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Gianluca Marucci
- Unit of Foodborne and Neglected Parasitic Diseases, Department of Infectious Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - Anna Munke
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Mohammad Maruf Hassan
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Marco Lalle
- Unit of Foodborne and Neglected Parasitic Diseases, Department of Infectious Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - Kenta Okamoto
- The Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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5
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Li Z, Xia H, Rao G, Fu Y, Chong T, Tian K, Yuan Z, Cao S. Cryo-EM structures of Banna virus in multiple states reveal stepwise detachment of viral spikes. Nat Commun 2024; 15:2284. [PMID: 38480794 PMCID: PMC10937716 DOI: 10.1038/s41467-024-46624-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 02/28/2024] [Indexed: 03/17/2024] Open
Abstract
Banna virus (BAV) is the prototype Seadornavirus, a class of reoviruses for which there has been little structural study. Here, we report atomic cryo-EM structures of three states of BAV virions-surrounded by 120 spikes (full virions), 60 spikes (partial virions), or no spikes (cores). BAV cores are double-layered particles similar to the cores of other non-turreted reoviruses, except for an additional protein component in the outer capsid shell, VP10. VP10 was identified to be a cementing protein that plays a pivotal role in the assembly of BAV virions by directly interacting with VP2 (inner capsid), VP8 (outer capsid), and VP4 (spike). Viral spikes (VP4/VP9 heterohexamers) are situated on top of VP10 molecules in full or partial virions. Asymmetrical electrostatic interactions between VP10 monomers and VP4 trimers are disrupted by high pH treatment, which is thus a simple way to produce BAV cores. Low pH treatment of BAV virions removes only the flexible receptor binding protein VP9 and triggers significant conformational changes in the membrane penetration protein VP4. BAV virions adopt distinct spatial organization of their surface proteins compared with other well-studied reoviruses, suggesting that BAV may have a unique mechanism of penetration of cellular endomembranes.
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Affiliation(s)
- Zhiqiang Li
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Han Xia
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Guibo Rao
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Yan Fu
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China
| | - Tingting Chong
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Kexing Tian
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China
- University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Zhiming Yuan
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China.
| | - Sheng Cao
- CAS Key Laboratory of Special Pathogens, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, 430071, PR China.
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6
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Li H, Liu Q, Shao L, Xiang Y. Structural Insights into the Assembly of the African Swine Fever Virus Inner Capsid. J Virol 2023; 97:e0026823. [PMID: 37191520 PMCID: PMC10308890 DOI: 10.1128/jvi.00268-23] [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: 02/21/2023] [Accepted: 04/21/2023] [Indexed: 05/17/2023] Open
Abstract
African swine fever virus (ASFV), the cause of a highly contagious hemorrhagic and fatal disease of domestic pigs, has a complex multilayer structure. The inner capsid of ASFV located underneath the inner membrane enwraps the genome-containing nucleoid and is likely the assembly of proteolytic products from the virally encoded polyproteins pp220 and pp62. Here, we report the crystal structure of ASFV p150△NC, a major middle fragment of the pp220 proteolytic product p150. The structure of ASFV p150△NC contains mainly helices and has a triangular plate-like shape. The triangular plate is approximately 38 Å in thickness, and the edge of the triangular plate is approximately 90 Å long. The structure of ASFV p150△NC is not homologous to any of the known viral capsid proteins. Further analysis of the cryo-electron microscopy maps of the ASFV and the homologous faustovirus inner capsids revealed that p150 or the p150-like protein of faustovirus assembles to form screwed propeller-shaped hexametric and pentametric capsomeres of the icosahedral inner capsids. Complexes of the C terminus of p150 and other proteolytic products of pp220 likely mediate interactions between the capsomeres. Together, these findings provide new insights into the assembling of ASFV inner capsid and provide a reference for understanding the assembly of the inner capsids of nucleocytoplasmic large DNA viruses (NCLDV). IMPORTANCE African swine fever virus has caused catastrophic destruction to the pork industry worldwide since it was first discovered in Kenya in 1921. The architecture of ASFV is complicated, with two protein shells and two membrane envelopes. Currently, mechanisms involved in the assembly of the ASFV inner core shell are less understood. The structural studies of the ASFV inner capsid protein p150 performed in this research enable the building of a partial model of the icosahedral ASFV inner capsid, which provides a structural basis for understanding the structure and assembly of this complex virion. Furthermore, the structure of ASFV p150△NC represents a new type of fold for viral capsid assembly, which could be a common fold for the inner capsid assembly of nucleocytoplasmic large DNA viruses (NCLDV) and would facilitate the development of vaccine and antivirus drugs against these complex viruses.
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Affiliation(s)
- Haining Li
- Center for Infectious Disease Research, Beijing Frontier Research Center for Biological Structure & Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Qi Liu
- Center for Infectious Disease Research, Beijing Frontier Research Center for Biological Structure & Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Luyuan Shao
- Center for Infectious Disease Research, Beijing Frontier Research Center for Biological Structure & Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
| | - Ye Xiang
- Center for Infectious Disease Research, Beijing Frontier Research Center for Biological Structure & Beijing Advanced Innovation Center for Structural Biology, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing, China
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7
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Sung PY, Zhou Y, Kao CC, Aburigh AA, Routh A, Roy P. A multidisciplinary approach to the identification of the protein-RNA connectome in double-stranded RNA virus capsids. Nucleic Acids Res 2023; 51:5210-5227. [PMID: 37070191 PMCID: PMC10250232 DOI: 10.1093/nar/gkad274] [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: 12/06/2022] [Revised: 03/31/2023] [Accepted: 04/04/2023] [Indexed: 04/19/2023] Open
Abstract
How multi-segmented double-stranded RNA (dsRNA) viruses correctly incorporate their genomes into their capsids remains unclear for many viruses, including Bluetongue virus (BTV), a Reoviridae member, with a genome of 10 segments. To address this, we used an RNA-cross-linking and peptide-fingerprinting assay (RCAP) to identify RNA binding sites of the inner capsid protein VP3, the viral polymerase VP1 and the capping enzyme VP4. Using a combination of mutagenesis, reverse genetics, recombinant proteins and in vitro assembly, we validated the importance of these regions in virus infectivity. Further, to identify which RNA segments and sequences interact with these proteins, we used viral photo-activatable ribonucleoside crosslinking (vPAR-CL) which revealed that the larger RNA segments (S1-S4) and the smallest segment (S10) have more interactions with viral proteins than the other smaller segments. Additionally, using a sequence enrichment analysis we identified an RNA motif of nine bases that is shared by the larger segments. The importance of this motif for virus replication was confirmed by mutagenesis followed by virus recovery. We further demonstrated that these approaches could be applied to a related Reoviridae member, rotavirus (RV), which has human epidemic impact, offering the possibility of novel intervention strategies for a human pathogen.
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Affiliation(s)
- Po-yu Sung
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Yiyang Zhou
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - C Cheng Kao
- Previously in the Department of Molecular & Cellular Biochemistry, Indiana University, Bloomington, IN, USA
| | - Ali A Aburigh
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Andrew Routh
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Polly Roy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
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8
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Monsion B, Mohd Jaafar F, Mertens PPC, Attoui H. Uncovering the Underlying Mechanisms Blocking Replication of Bluetongue Virus Serotype 26 (BTV-26) in Culicoides Cells. Biomolecules 2023; 13:878. [PMID: 37371457 DOI: 10.3390/biom13060878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/05/2023] [Accepted: 05/18/2023] [Indexed: 06/29/2023] Open
Abstract
At least 12 serotypes of 'atypical' bluetongue virus (BTV-25 to BTV-36) have been identified to date. These atypical serotypes fail to infect/replicate in Culicoides-derived cell lines and/or adult Culicoides vectors and hence can no longer be transmitted by these vectors. They appear to be horizontally transmitted from infected to in-contact ruminants, although the route(s) of infection remain to be identified. Viral genome segments 1, 2 and 3 (Seg-1, Seg2 and Seg-3) of BTV-26 were identified as involved in blocking virus replication in KC cells. We have developed Culicoides-specific expression plasmids, which we used in transfected insect cells to assess the stability of viral mRNAs and protein expression from full-length open reading frames of Seg-1, -2 and -3 of BTV-1 (a Culicoides-vectored BTV) or BTV-26. Our results indicate that the blocked replication of BTV-26 in KC cells is not due to an RNAi response, which would lead to rapid degradation of viral mRNAs. A combination of degradation/poor expression and/or modification of the proteins encoded by these segments appears to drive the failure of BTV-26 core/whole virus-particles to assemble and replicate effectively in Culicoides cells.
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Affiliation(s)
- Baptiste Monsion
- UMR1161 VIROLOGIE, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, F-94700 Maisons-Alfort, France
| | - Fauziah Mohd Jaafar
- UMR1161 VIROLOGIE, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, F-94700 Maisons-Alfort, France
| | - Peter P C Mertens
- One Virology, The Wolfson Centre for Global Virus Research, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, Leicestershire, UK
| | - Houssam Attoui
- UMR1161 VIROLOGIE, INRAE, Ecole Nationale Vétérinaire d'Alfort, ANSES, Université Paris-Est, F-94700 Maisons-Alfort, France
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9
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Zhang Q, Gao Y, Baker ML, Liu S, Jia X, Xu H, He J, Kaelber JT, Weng S, Jiang W. The structure of a 12-segmented dsRNA reovirus: New insights into capsid stabilization and organization. PLoS Pathog 2023; 19:e1011341. [PMID: 37083840 PMCID: PMC10155992 DOI: 10.1371/journal.ppat.1011341] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 05/03/2023] [Accepted: 04/02/2023] [Indexed: 04/22/2023] Open
Abstract
Infecting a wide range of hosts, members of Reovirales (formerly Reoviridae) consist of a genome with different numbers of segmented double stranded RNAs (dsRNA) encapsulated by a proteinaceous shell and carry out genome replication and transcription inside the virion. Several cryo-electron microscopy (cryo-EM) structures of reoviruses with 9, 10 or 11 segmented dsRNA genomes have revealed insights into genome arrangement and transcription. However, the structure and genome arrangement of 12-segmented Reovirales members remain poorly understood. Using cryo-EM, we determined the structure of mud crab reovirus (MCRV), a 12-segmented dsRNA virus that is a putative member of Reovirales in the non-turreted Sedoreoviridae family, to near-atomic resolutions with icosahedral symmetry (3.1 Å) and without imposing icosahedral symmetry (3.4 Å). These structures revealed the organization of the major capsid proteins in two layers: an outer T = 13 layer consisting of VP12 trimers and unique VP11 clamps, and an inner T = 1 layer consisting of VP3 dimers. Additionally, ten RNA dependent RNA polymerases (RdRp) were well resolved just below the VP3 layer but were offset from the 5-fold axes and arranged with D5 symmetry, which has not previously been seen in other members of Reovirales. The N-termini of VP3 were shown to adopt four unique conformations; two of which anchor the RdRps, while the other two conformations are likely involved in genome organization and capsid stability. Taken together, these structures provide a new level of understanding for capsid stabilization and genome organization of segmented dsRNA viruses.
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Affiliation(s)
- Qinfen Zhang
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yuanzhu Gao
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Matthew L Baker
- Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at the University of Texas Health Science Center, Houston, Texas, United States of America
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shanshan Liu
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xudong Jia
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Haidong Xu
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianguo He
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jason T Kaelber
- Institute for Quantitative Biomedicine, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Shaoping Weng
- State key lab for biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wen Jiang
- Markey Center for Structural Biology, Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
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10
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Roy P, Veesler D, Rey F. Virus structures and molecular biology exchange glances. Structure 2023; 31:S0969-2126(23)00034-5. [PMID: 36841235 DOI: 10.1016/j.str.2023.01.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 01/20/2023] [Accepted: 01/30/2023] [Indexed: 02/27/2023]
Abstract
The definition of structure as the arrangement of and relations between the parts of something complex has always been a challenge in virology. The balance required for a virus to be sufficiently stable to allow transmission yet also be primed for disassembly on contact with a permissive cell is precarious and seemingly difficult to attain. Add to this that virus structural components often have multiple functions such as receptor binding, fusion, and cleavage, and the puzzle deepens. It also has consequences: virus yields may be compromised, vaccine shelf-life may be limited, and the ability to quickly evolve away from an intervention may be underestimated. Progress in understanding virus structure and the ways in which it might be exploited were the subject of the latest International Virus Assembly Symposium. Whole viruses, individual components, and transient intermediates were revealed at sufficiently high resolution to deduce the mechanisms concerned.
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Affiliation(s)
- Polly Roy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK.
| | - David Veesler
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195, USA
| | - Felix Rey
- Structural Virology Unit Virology Department and CNRS UMR3569 Institut Pasteur, Paris, France
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11
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In situ structures of polymerase complex of mammalian reovirus illuminate RdRp activation and transcription regulation. Proc Natl Acad Sci U S A 2022; 119:e2203054119. [PMID: 36469786 PMCID: PMC9897473 DOI: 10.1073/pnas.2203054119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022] Open
Abstract
Mammalian reovirus (reovirus) is a multilayered, turreted member of Reoviridae characterized by transcription of dsRNA genome within the innermost capsid shell. Here, we present high-resolution in situ structures of reovirus transcriptase complex in an intact double-layered virion, and in the uncoated single-layered core particles in the unloaded, reloaded, pre-elongation, and elongation states, respectively, obtained by cryo-electron microscopy and sub-particle reconstructions. At the template entry of RNA-dependent RNA polymerase (RdRp), the RNA-loading region gets flexible after uncoating resulting in the unloading of terminal genomic RNA and inactivity of transcription. However, upon adding transcriptional substrates, the RNA-loading region is recovered leading the RNAs loaded again. The priming loop in RdRp was found to play a critical role in regulating transcription, which hinders the elongation of transcript in virion and triggers the rearrangement of RdRp C-terminal domain (CTD) during elongation, resulting in splitting of template-transcript hybrid and opening of transcript exit. With the integration of these structures, a transcriptional model of reovirus with five states is proposed. Our structures illuminate the RdRp activation and regulation of the multilayered turreted reovirus.
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12
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Procházková M, Füzik T, Grybchuk D, Yurchenko V, Plevka P. Virion structure of Leishmania RNA virus 1. Virology 2022; 577:149-154. [PMID: 36371873 DOI: 10.1016/j.virol.2022.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 09/29/2022] [Indexed: 11/05/2022]
Abstract
The presence of Leishmania RNA virus 1 (LRV1) enables Leishmania protozoan parasites to cause more severe disease than the virus-free strains. The structure of LRV1 virus-like particles has been determined previously, however, the structure of the LRV1 virion has not been characterized. Here we used cryo-electron microscopy and single-particle reconstruction to determine the structures of the LRV1 virion and empty particle isolated from Leishmania guyanensis to resolutions of 4.0 Å and 3.6 Å, respectively. The capsid of LRV1 is built from sixty dimers of capsid proteins organized with icosahedral symmetry. RNA genomes of totiviruses are replicated inside the virions by RNA polymerases expressed as C-terminal extensions of a sub-population of capsid proteins. Most of the virions probably contain one or two copies of the RNA polymerase, however, the location of the polymerase domains in LRV1 capsid could not be identified, indicating that it varies among particles. Importance. Every year over 200 000 people contract leishmaniasis and more than five hundred people die of the disease. The mucocutaneous form of leishmaniasis produces lesions that can destroy the mucous membranes of the nose, mouth, and throat. Leishmania parasites carrying Leishmania RNA virus 1 (LRV1) are predisposed to cause aggravated symptoms in the mucocutaneous form of leishmaniasis. Here, we present the structure of the LRV1 virion determined using cryo-electron microscopy.
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Affiliation(s)
- Michaela Procházková
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Tibor Füzik
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Danyil Grybchuk
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Chittussiho 10, Ostrava, 710 00, Czech Republic
| | - Pavel Plevka
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic.
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13
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Xia X, Zhou ZH. Using cryoEM and cryoET to visualize membrane penetration of a non-enveloped virus. STAR Protoc 2022; 3:101825. [PMID: 36595958 PMCID: PMC9667302 DOI: 10.1016/j.xpro.2022.101825] [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: 06/28/2022] [Revised: 08/20/2022] [Accepted: 10/07/2022] [Indexed: 11/13/2022] Open
Abstract
Key to cell entry by non-enveloped viruses is virus-cell interactions at the cell or endosomal membrane. Here, we detail our protocols to capture such interactions between non-enveloped virus bluetongue virus (BTV) and vesicular membrane by cryogenic electron microscopy (cryoEM) and tomography (cryoET). Key steps include virus isolation, liposome preparation, virus-liposome incubation and vitrification, cryoEM and cryoET imaging, data processing for 3D reconstruction, and subtomogram averaging. The protocols can be generally applicable to studies of cell entry by other non-enveloped viruses. For complete details on the use and execution of this protocol, please refer to Xia et al. (2021).
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Affiliation(s)
- Xian Xia
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, 90095, USA,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Z. Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, 90095, USA,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA,Corresponding author
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14
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Ramaswamy K, Rashid M, Ramasamy S, Jayavelu T, Venkataraman S. Revisiting Viral RNA-Dependent RNA Polymerases: Insights from Recent Structural Studies. Viruses 2022; 14:2200. [PMID: 36298755 PMCID: PMC9612308 DOI: 10.3390/v14102200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/29/2022] [Accepted: 10/02/2022] [Indexed: 11/07/2022] Open
Abstract
RNA-dependent RNA polymerases (RdRPs) represent a distinctive yet versatile class of nucleic acid polymerases encoded by RNA viruses for the replication and transcription of their genome. The structure of the RdRP is comparable to that of a cupped right hand consisting of fingers, palm, and thumb subdomains. Despite the presence of a common structural core, the RdRPs differ significantly in the mechanistic details of RNA binding and polymerization. The present review aims at exploring these incongruities in light of recent structural studies of RdRP complexes with diverse cofactors, RNA moieties, analogs, and inhibitors.
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Affiliation(s)
- Kavitha Ramaswamy
- Department of Biotechnology, Anna University, Sardar Patel Road, Guindy, Chennai 600025, India; (K.R.); (T.J.)
| | - Mariya Rashid
- Taiwan International Graduate Program, Molecular Cell Biology (National Defense Medical Center and Academia Sinica), Taipei 115, Taiwan;
| | - Selvarajan Ramasamy
- National Research Center for Banana, Somarasempettai−Thogaimalai Rd, Podavur, Tamil Nadu 639103, India;
| | - Tamilselvan Jayavelu
- Department of Biotechnology, Anna University, Sardar Patel Road, Guindy, Chennai 600025, India; (K.R.); (T.J.)
| | - Sangita Venkataraman
- Department of Biotechnology, Anna University, Sardar Patel Road, Guindy, Chennai 600025, India; (K.R.); (T.J.)
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15
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Grybchuk D, Procházková M, Füzik T, Konovalovas A, Serva S, Yurchenko V, Plevka P. Structures of L-BC virus and its open particle provide insight into Totivirus capsid assembly. Commun Biol 2022; 5:847. [PMID: 35986212 PMCID: PMC9391438 DOI: 10.1038/s42003-022-03793-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/03/2022] [Indexed: 11/18/2022] Open
Abstract
L-BC virus persists in the budding yeast Saccharomyces cerevisiae, whereas other viruses from the family Totiviridae infect a diverse group of organisms including protists, fungi, arthropods, and vertebrates. The presence of totiviruses alters the fitness of the host organisms, for example, by maintaining the killer system in yeast or increasing the virulence of Leishmania guyanensis. Despite the importance of totiviruses for their host survival, there is limited information about Totivirus structure and assembly. Here we used cryo-electron microscopy to determine the structure of L-BC virus to a resolution of 2.9 Å. The L-BC capsid is organized with icosahedral symmetry, with each asymmetric unit composed of two copies of the capsid protein. Decamers of capsid proteins are stabilized by domain swapping of the C-termini of subunits located around icosahedral fivefold axes. We show that capsids of 9% of particles in a purified L-BC sample were open and lacked one decamer of capsid proteins. The existence of the open particles together with domain swapping within a decamer provides evidence that Totiviridae capsids assemble from the decamers of capsid proteins. Furthermore, the open particles may be assembly intermediates that are prepared for the incorporation of the virus (+) strand RNA. A 2.9 Å resolution structure of the L-BC virus provides insight into the contacts between capsid proteins and the mechanism of capsid assembly.
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16
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Liu H, Cheng L. Viral Capsid and Polymerase in Reoviridae. Subcell Biochem 2022; 99:525-552. [PMID: 36151388 DOI: 10.1007/978-3-031-00793-4_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The members of the family Reoviridae (reoviruses) consist of 9-12 discrete double-stranded RNA (dsRNA) segments enclosed by single, double, or triple capsid layers. The outer capsid proteins of reoviruses exhibit the highest diversity in both sequence and structural organization. By contrast, the conserved RNA-dependent RNA polymerase (RdRp) structure in the conserved innermost shell in all reoviruses suggests that they share common transcriptional regulatory mechanisms. After reoviruses are delivered into the cytoplasm of a host cell, their inner capsid particles (ICPs) remain intact and serve as a stable nanoscale machine for RNA transcription and capping performed using enzymes in ICPs. Advances in cryo-electron microscopy have enabled the reconstruction at near-atomic resolution of not only the icosahedral capsid, including capping enzymes, but also the nonicosahedrally distributed complexes of RdRps within the capsid at different transcriptional stages. These near-atomic resolution structures allow us to visualize highly coordinated structural changes in the related enzymes, genomic RNA, and capsid protein during reovirus transcription. In addition, reoviruses encode their own enzymes for nascent RNA capping before RNA releasing from their ICPs.
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Affiliation(s)
- Hongrong Liu
- Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha, China.
| | - Lingpeng Cheng
- Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha, China.
- School of Life Sciences, Tsinghua University, Beijing, China.
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17
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Vaccination as a Strategy to Prevent Bluetongue Virus Vertical Transmission. Pathogens 2021; 10:pathogens10111528. [PMID: 34832683 PMCID: PMC8622840 DOI: 10.3390/pathogens10111528] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/13/2021] [Accepted: 11/19/2021] [Indexed: 11/17/2022] Open
Abstract
Bluetongue virus (BTV) produces an economically important disease in ruminants of compulsory notification to the OIE. BTV is typically transmitted by the bite of Culicoides spp., however, some BTV strains can be transmitted vertically, and this is associated with fetus malformations and abortions. The viral factors associated with the virus potency to cross the placental barrier are not well defined. The potency of vertical transmission is retained and sometimes even increased in live attenuated BTV vaccine strains. Because BTV possesses a segmented genome, the possibility of reassortment of vaccination strains with wild-type virus could even favor the transmission of this phenotype. In the present review, we will describe the non-vector-based BTV infection routes and discuss the experimental vaccination strategies that offer advantages over this drawback of some live attenuated BTV vaccines.
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18
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Xia X, Wu W, Cui Y, Roy P, Zhou ZH. Bluetongue virus capsid protein VP5 perforates membranes at low endosomal pH during viral entry. Nat Microbiol 2021; 6:1424-1432. [PMID: 34702979 PMCID: PMC9015746 DOI: 10.1038/s41564-021-00988-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/22/2021] [Indexed: 01/25/2023]
Abstract
Bluetongue virus (BTV) is a non-enveloped virus and causes substantial morbidity and mortality in ruminants such as sheep. Fashioning a receptor-binding protein (VP2) and a membrane penetration protein (VP5) on the surface, BTV releases its genome-containing core (VP3 and VP7) into the host cell cytosol after perforation of the endosomal membrane. Unlike enveloped ones, the entry mechanisms of non-enveloped viruses into host cells remain poorly understood. Here we applied single-particle cryo-electron microscopy, cryo-electron tomography and structure-guided functional assays to characterize intermediate states of BTV cell entry in endosomes. Four structures of BTV at the resolution range of 3.4-3.9 Å show the different stages of structural rearrangement of capsid proteins on exposure to low pH, including conformational changes of VP5, stepwise detachment of VP2 and a small shift of VP7. In detail, sensing of the low-pH condition by the VP5 anchor domain triggers three major VP5 actions: projecting the hidden dagger domain, converting a surface loop to a protonated β-hairpin that anchors VP5 to the core and stepwise refolding of the unfurling domains into a six-helix stalk. Cryo-electron tomography structures of BTV interacting with liposomes show a length decrease of the VP5 stalk from 19.5 to 15.5 nm after its insertion into the membrane. Our structures, functional assays and structure-guided mutagenesis experiments combined indicate that this stalk, along with dagger domain and the WHXL motif, creates a single pore through the endosomal membrane that enables the viral core to enter the cytosol. Our study unveils the detailed mechanisms of BTV membrane penetration and showcases general methods to study cell entry of other non-enveloped viruses.
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Affiliation(s)
- Xian Xia
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Weining Wu
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Polly Roy
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.
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19
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RNA Origami: Packaging a Segmented Genome in Orbivirus Assembly and Replication. Viruses 2021; 13:v13091841. [PMID: 34578422 PMCID: PMC8473007 DOI: 10.3390/v13091841] [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: 08/05/2021] [Revised: 09/07/2021] [Accepted: 09/11/2021] [Indexed: 01/04/2023] Open
Abstract
Understanding how viruses with multi-segmented genomes incorporate one copy of each segment into their capsids remains an intriguing question. Here, we review our recent progress and describe the advancements made in understanding the genome packaging mechanism of a model nonenveloped virus, Bluetongue virus (BTV), with a 10-segment (S1–S10) double-strand RNA (dsRNA) genome. BTV (multiple serotypes), a member of the Orbivirus genus in the Reoviridae family, is a notable pathogen for livestock and is responsible for significant economic losses worldwide. This has enabled the creation of an extensive set of reagents and assays, including reverse genetics, cell-free RNA packaging, and bespoke bioinformatics approaches, which can be directed to address the packaging question. Our studies have shown that (i) UTRs enable the conformation of each segment necessary for the next level of RNA–RNA interaction; (ii) a specific order of intersegment interactions leads to a complex RNA network containing all the active components in sorting and packaging; (iii) networked segments are recruited into nascent assembling capsids; and (iv) select capsid proteins might be involved in the packaging process. The key features of genome packaging mechanisms for BTV and related dsRNA viruses are novel and open up new avenues of potential intervention.
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20
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Pan M, Alvarez-Cabrera AL, Kang JS, Wang L, Fan C, Zhou ZH. Asymmetric reconstruction of mammalian reovirus reveals interactions among RNA, transcriptional factor µ2 and capsid proteins. Nat Commun 2021; 12:4176. [PMID: 34234134 PMCID: PMC8263624 DOI: 10.1038/s41467-021-24455-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/17/2021] [Indexed: 12/02/2022] Open
Abstract
Mammalian reovirus (MRV) is the prototypical member of genus Orthoreovirus of family Reoviridae. However, lacking high-resolution structures of its RNA polymerase cofactor μ2 and infectious particle, limits understanding of molecular interactions among proteins and RNA, and their contributions to virion assembly and RNA transcription. Here, we report the 3.3 Å-resolution asymmetric reconstruction of transcribing MRV and in situ atomic models of its capsid proteins, the asymmetrically attached RNA-dependent RNA polymerase (RdRp) λ3, and RdRp-bound nucleoside triphosphatase μ2 with a unique RNA-binding domain. We reveal molecular interactions among virion proteins and genomic and messenger RNA. Polymerase complexes in three Spinoreovirinae subfamily members are organized with different pseudo-D3d symmetries to engage their highly diversified genomes. The above interactions and those between symmetry-mismatched receptor-binding σ1 trimers and RNA-capping λ2 pentamers balance competing needs of capsid assembly, external protein removal, and allosteric triggering of endogenous RNA transcription, before, during and after infection, respectively. Mammalian reovirus (MRV) is a double-stranded RNA (dsRNA) virus that affects the gastrointestinal and respiratory tracts. Here, the authors present the 3.3 Å cryo-EM asymmetric reconstruction of transcribing MRV that reveals the organization of the dsRNA genome, RNA interaction with the polymerase complex, and how the polymerase interacts extensively with its co-factor, µ2, to form a transcription enzyme complex, which engages and regulates RNA transcription.
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Affiliation(s)
- Muchen Pan
- CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.,California NanoSystems Institute, UCLA, Los Angeles, CA, USA.,University of Chinese Academy of Sciences, Beijing, China.,School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Ana L Alvarez-Cabrera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.,California NanoSystems Institute, UCLA, Los Angeles, CA, USA
| | - Joon S Kang
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA.,California NanoSystems Institute, UCLA, Los Angeles, CA, USA.,Molecular Biology Institute, UCLA, Los Angeles, CA, USA
| | - Lihua Wang
- CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China.,The Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA, USA. .,California NanoSystems Institute, UCLA, Los Angeles, CA, USA. .,Molecular Biology Institute, UCLA, Los Angeles, CA, USA.
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21
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Structure Unveils Relationships between RNA Virus Polymerases. Viruses 2021; 13:v13020313. [PMID: 33671332 PMCID: PMC7922027 DOI: 10.3390/v13020313] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/14/2021] [Accepted: 02/15/2021] [Indexed: 12/30/2022] Open
Abstract
RNA viruses are the fastest evolving known biological entities. Consequently, the sequence similarity between homologous viral proteins disappears quickly, limiting the usability of traditional sequence-based phylogenetic methods in the reconstruction of relationships and evolutionary history among RNA viruses. Protein structures, however, typically evolve more slowly than sequences, and structural similarity can still be evident, when no sequence similarity can be detected. Here, we used an automated structural comparison method, homologous structure finder, for comprehensive comparisons of viral RNA-dependent RNA polymerases (RdRps). We identified a common structural core of 231 residues for all the structurally characterized viral RdRps, covering segmented and non-segmented negative-sense, positive-sense, and double-stranded RNA viruses infecting both prokaryotic and eukaryotic hosts. The grouping and branching of the viral RdRps in the structure-based phylogenetic tree follow their functional differentiation. The RdRps using protein primer, RNA primer, or self-priming mechanisms have evolved independently of each other, and the RdRps cluster into two large branches based on the used transcription mechanism. The structure-based distance tree presented here follows the recently established RdRp-based RNA virus classification at genus, subfamily, family, order, class and subphylum ranks. However, the topology of our phylogenetic tree suggests an alternative phylum level organization.
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22
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Chandler-Bostock R, Mata CP, Bingham RJ, Dykeman EC, Meng B, Tuthill TJ, Rowlands DJ, Ranson NA, Twarock R, Stockley PG. Assembly of infectious enteroviruses depends on multiple, conserved genomic RNA-coat protein contacts. PLoS Pathog 2020; 16:e1009146. [PMID: 33370422 PMCID: PMC7793301 DOI: 10.1371/journal.ppat.1009146] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 01/08/2021] [Accepted: 11/11/2020] [Indexed: 02/04/2023] Open
Abstract
Picornaviruses are important viral pathogens, but despite extensive study, the assembly process of their infectious virions is still incompletely understood, preventing the development of anti-viral strategies targeting this essential part of the life cycle. We report the identification, via RNA SELEX and bioinformatics, of multiple RNA sites across the genome of a typical enterovirus, enterovirus-E (EV-E), that each have affinity for the cognate viral capsid protein (CP) capsomer. Many of these sites are evolutionarily conserved across known EV-E variants, suggesting they play essential functional roles. Cryo-electron microscopy was used to reconstruct the EV-E particle at ~2.2 Å resolution, revealing extensive density for the genomic RNA. Relaxing the imposed symmetry within the reconstructed particles reveals multiple RNA-CP contacts, a first for any picornavirus. Conservative mutagenesis of the individual RNA-contacting amino acid side chains in EV-E, many of which are conserved across the enterovirus family including poliovirus, is lethal but does not interfere with replication or translation. Anti-EV-E and anti-poliovirus aptamers share sequence similarities with sites distributed across the poliovirus genome. These data are consistent with the hypothesis that these RNA-CP contacts are RNA Packaging Signals (PSs) that play vital roles in assembly and suggest that the RNA PSs are evolutionarily conserved between pathogens within the family, augmenting the current protein-only assembly paradigm for this family of viruses.
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Affiliation(s)
- Rebecca Chandler-Bostock
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Carlos P. Mata
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Richard J. Bingham
- Department of Mathematics, University of York, York, United Kingdom
- Department of Biology, University of York, York, United Kingdom
- York Cross-disciplinary Centre for Systems Analysis, University of York, York, United Kingdom
| | - Eric C. Dykeman
- Department of Mathematics, University of York, York, United Kingdom
- York Cross-disciplinary Centre for Systems Analysis, University of York, York, United Kingdom
| | - Bo Meng
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Tobias J. Tuthill
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - David J. Rowlands
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail: (DJR); (NAR); (RT); (PGS)
| | - Neil A. Ranson
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail: (DJR); (NAR); (RT); (PGS)
| | - Reidun Twarock
- Department of Mathematics, University of York, York, United Kingdom
- Department of Biology, University of York, York, United Kingdom
- York Cross-disciplinary Centre for Systems Analysis, University of York, York, United Kingdom
- * E-mail: (DJR); (NAR); (RT); (PGS)
| | - Peter G. Stockley
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- * E-mail: (DJR); (NAR); (RT); (PGS)
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23
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Dedkov VG, Dolgova AS, Safonova MV, Samoilov AE, Belova OA, Kholodilov IS, Matsvay AD, Speranskaya AS, Khafizov K, Karganova GG. Isolation and characterization of Wad Medani virus obtained in the tuva Republic of Russia. Ticks Tick Borne Dis 2020; 12:101612. [PMID: 33291056 DOI: 10.1016/j.ttbdis.2020.101612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 11/05/2020] [Accepted: 11/11/2020] [Indexed: 10/22/2022]
Abstract
Wad Medani virus (WMV) belongs to the genus Orbivirus and is a poorly studied arbovirus with unclear medical significance. Presently, a limited number of WMV strains are characterized and available in NCBI GenBank, some isolated many years ago. A new WMV strain was isolated in 2012 from Dermacentor nuttalli ticks collected from sheep in the Tuva Republic, Russia, and sequenced using high-throughput methods. Complete coding sequences were obtained revealing signs of multiple intersegment reassortments. These point to a high variability potential in WMV that may lead to the formation of strains with novel properties. These new data on WMV can promote better understanding of: ecological features of its circulation; relationships within the genus Orbivirus; and the medical significance of the virus.
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Affiliation(s)
- Vladimir G Dedkov
- Saint-Petersburg Pasteur Institute, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Saint-Petersburg, Russia; Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Anna S Dolgova
- Saint-Petersburg Pasteur Institute, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Saint-Petersburg, Russia
| | - Marina V Safonova
- Anti-Plague Center, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Moscow, Russia
| | - Andrei E Samoilov
- Saint-Petersburg Pasteur Institute, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Saint-Petersburg, Russia; Central Research Institute for Epidemiology, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Moscow, Russia
| | - Oxana A Belova
- Chumakov Institute of Poliomyelitis and Viral Encephalitides FSBSI Chumakov FSC R&D IBP RAS, Moscow, Russia
| | - Ivan S Kholodilov
- Chumakov Institute of Poliomyelitis and Viral Encephalitides FSBSI Chumakov FSC R&D IBP RAS, Moscow, Russia
| | - Alina D Matsvay
- FSBI "Center of Strategic Planning" of the Ministry of Health, Moscow, Russia; Moscow Institute of Physics and Technology, National Research University, Dolgoprudny, Russia
| | - Anna S Speranskaya
- Central Research Institute for Epidemiology, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Moscow, Russia
| | - Kamil Khafizov
- Central Research Institute for Epidemiology, Federal Service on Consumers' Rights Protection and Human Well-Being Surveillance, Moscow, Russia; Moscow Institute of Physics and Technology, National Research University, Dolgoprudny, Russia
| | - Galina G Karganova
- Chumakov Institute of Poliomyelitis and Viral Encephalitides FSBSI Chumakov FSC R&D IBP RAS, Moscow, Russia; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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24
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Cryo-electron Microscopy Structure, Assembly, and Mechanics Show Morphogenesis and Evolution of Human Picobirnavirus. J Virol 2020; 94:JVI.01542-20. [PMID: 32938763 DOI: 10.1128/jvi.01542-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/08/2020] [Indexed: 12/17/2022] Open
Abstract
Despite their diversity, most double-stranded-RNA (dsRNA) viruses share a specialized T=1 capsid built from dimers of a single protein that provides a platform for genome transcription and replication. This ubiquitous capsid remains structurally undisturbed throughout the viral cycle, isolating the genome to avoid triggering host defense mechanisms. Human picobirnavirus (hPBV) is a dsRNA virus frequently associated with gastroenteritis, although its pathogenicity is yet undefined. Here, we report the cryo-electron microscopy (cryo-EM) structure of hPBV at 2.6-Å resolution. The capsid protein (CP) is arranged in a single-shelled, ∼380-Å-diameter T=1 capsid with a rough outer surface similar to that of dsRNA mycoviruses. The hPBV capsid is built of 60 quasisymmetric CP dimers (A and B) stabilized by domain swapping, and only the CP-A N-terminal basic region interacts with the packaged nucleic acids. hPBV CP has an α-helical domain with a fold similar to that of fungal partitivirus CP, with many domain insertions in its C-terminal half. In contrast to dsRNA mycoviruses, hPBV has an extracellular life cycle phase like complex reoviruses, which indicates that its own CP probably participates in cell entry. Using an in vitro reversible assembly/disassembly system of hPBV, we isolated tetramers as possible assembly intermediates. We used atomic force microscopy to characterize the biophysical properties of hPBV capsids with different cargos (host nucleic acids or proteins) and found that the CP N-terminal segment not only is involved in nucleic acid interaction/packaging but also modulates the mechanical behavior of the capsid in conjunction with the cargo.IMPORTANCE Despite intensive study, human virus sampling is still sparse, especially for viruses that cause mild or asymptomatic disease. Human picobirnavirus (hPBV) is a double-stranded-RNA virus, broadly dispersed in the human population, but its pathogenicity is uncertain. Here, we report the hPBV structure derived from cryo-electron microscopy (cryo-EM) and reconstruction methods using three capsid protein variants (of different lengths and N-terminal amino acid compositions) that assemble as virus-like particles with distinct properties. The hPBV near-atomic structure reveals a quasisymmetric dimer as the structural subunit and tetramers as possible assembly intermediates that coassemble with nucleic acids. Our structural studies and atomic force microscopy analyses indicate that hPBV capsids are potentially excellent nanocages for gene therapy and targeted drug delivery in humans.
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Mata CP, Rodríguez JM, Suzuki N, Castón JR. Structure and assembly of double-stranded RNA mycoviruses. Adv Virus Res 2020; 108:213-247. [PMID: 33837717 DOI: 10.1016/bs.aivir.2020.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycoviruses are a diverse group that includes ssRNA, dsRNA, and ssDNA viruses, with or without a protein capsid, as well as with a complex envelope. Most mycoviruses are transmitted by cytoplasmic interchange and are thought to lack an extracellular phase in their infection cycle. Structural analysis has focused on dsRNA mycoviruses, which usually package their genome in a 120-subunit T=1 icosahedral capsid, with a capsid protein (CP) dimer as the asymmetric unit. The atomic structure is available for four dsRNA mycovirus from different families: Saccharomyces cerevisiae virus L-A (ScV-L-A), Penicillium chrysogenum virus (PcV), Penicillium stoloniferum virus F (PsV-F), and Rosellinia necatrix quadrivirus 1 (RnQV1). Their capsids show structural variations of the same framework, with asymmetric or symmetric CP dimers respectively for ScV-L-A and PsV-F, dimers of similar domains of a single CP for PcV, or of two different proteins for RnQV1. The CP dimer is the building block, and assembly proceeds through dimers of dimers or pentamers of dimers, in which the genome is packed as ssRNA by interaction with CP and/or viral polymerase. These capsids remain structurally undisturbed throughout the viral cycle. The T=1 capsid participates in RNA synthesis, organizing the viral polymerase (1-2 copies) and a single loosely packaged genome segment. It also acts as a molecular sieve, to allow the passage of viral transcripts and nucleotides, but to prevent triggering of host defense mechanisms. Due to the close mycovirus-host relationship, CP evolved to allocate peptide insertions with enzyme activity, as reflected in a rough outer capsid surface.
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Affiliation(s)
- Carlos P Mata
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain; Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Javier M Rodríguez
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
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26
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Roy P. Bluetongue virus assembly and exit pathways. Adv Virus Res 2020; 108:249-273. [PMID: 33837718 DOI: 10.1016/bs.aivir.2020.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bluetongue virus (BTV) is an insect-vectored emerging pathogen of wild ruminants and livestock in many parts of the world. The virion particle is a complex structure of consecutive layers of protein surrounding a genome of 10 double-stranded (ds) RNA segments. BTV has been studied extensively as a model system for large, nonenveloped dsRNA viruses. A combination of recombinant proteins and particles together with reverse genetics, high-resolution structural analysis by X-ray crystallography and cryo-electron microscopy techniques have been utilized to provide an order for the assembly of the capsid shell and the protein sequestration required for it. Further, a reconstituted in vitro assembly system and RNA-RNA interaction assay, have defined the individual steps required for the assembly and packaging of the 10-segmented RNA genome. In addition, various microscopic techniques have been utilized to illuminate the stages of virus maturation and its egress via multiple pathways. These findings have not only given an overall understanding of BTV assembly and morphogenesis but also indicated that similar assembly and egress pathways are likely to be used by related viruses and provided an informed starting point for intervention or prevention.
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Affiliation(s)
- Polly Roy
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
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27
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Beren C, Cui Y, Chakravarty A, Yang X, Rao ALN, Knobler CM, Zhou ZH, Gelbart WM. Genome organization and interaction with capsid protein in a multipartite RNA virus. Proc Natl Acad Sci U S A 2020; 117:10673-10680. [PMID: 32358197 PMCID: PMC7245085 DOI: 10.1073/pnas.1915078117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We report the asymmetric reconstruction of the single-stranded RNA (ssRNA) content in one of the three otherwise identical virions of a multipartite RNA virus, brome mosaic virus (BMV). We exploit a sample consisting exclusively of particles with the same RNA content-specifically, RNAs 3 and 4-assembled in planta by agrobacterium-mediated transient expression. We find that the interior of the particle is nearly empty, with most of the RNA genome situated at the capsid shell. However, this density is disordered in the sense that the RNA is not associated with any particular structure but rather, with an ensemble of secondary/tertiary structures that interact with the capsid protein. Our results illustrate a fundamental difference between the ssRNA organization in the multipartite BMV viral capsid and the monopartite bacteriophages MS2 and Qβ for which a dominant RNA conformation is found inside the assembled viral capsids, with RNA density conserved even at the center of the particle. This can be understood in the context of the differing demands on their respective lifecycles: BMV must package separately each of several different RNA molecules and has been shown to replicate and package them in isolated, membrane-bound, cytoplasmic complexes, whereas the bacteriophages exploit sequence-specific "packaging signals" throughout the viral RNA to package their monopartite genomes.
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Affiliation(s)
- Christian Beren
- Department of Chemistry & Biochemistry, University of California, Los Angeles, CA 90095
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, CA 90095
| | - Antara Chakravarty
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521
| | - Xue Yang
- California NanoSystems Institute, University of California, Los Angeles, CA 90095
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA 90095
| | - A L N Rao
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521;
| | - Charles M Knobler
- Department of Chemistry & Biochemistry, University of California, Los Angeles, CA 90095
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles, CA 90095;
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles, CA 90095
| | - William M Gelbart
- Department of Chemistry & Biochemistry, University of California, Los Angeles, CA 90095;
- California NanoSystems Institute, University of California, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, CA 90095
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28
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Kumar D, Yu X, Crawford SE, Moreno R, Jakana J, Sankaran B, Anish R, Kaundal S, Hu L, Estes MK, Wang Z, Prasad BVV. 2.7 Å cryo-EM structure of rotavirus core protein VP3, a unique capping machine with a helicase activity. SCIENCE ADVANCES 2020; 6:eaay6410. [PMID: 32494598 PMCID: PMC7159914 DOI: 10.1126/sciadv.aay6410] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 01/22/2020] [Indexed: 05/08/2023]
Abstract
In many viruses, including rotavirus (RV), the major pathogen of infantile gastroenteritis, capping of viral messenger RNAs is a pivotal step for efficient translation of the viral genome. In RV, VP3 caps the nascent transcripts synthesized from the genomic dsRNA segments by the RV polymerase VP1 within the particle core. Here, from cryo-electron microscopy, x-ray crystallography, and biochemical analyses, we show that VP3 forms a stable tetrameric assembly with each subunit having a modular domain organization, which uniquely integrates five distinct enzymatic steps required for capping the transcripts. In addition to the previously known guanylyl- and methyltransferase activities, we show that VP3 exhibits hitherto unsuspected RNA triphosphatase activity necessary for initiating transcript capping and RNA helicase activity likely required for separating the RNA duplex formed transiently during endogenous transcription. From our studies, we propose a new mechanism for how VP3 inside the virion core caps the nascent transcripts exiting from the polymerase.
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Affiliation(s)
- Dilip Kumar
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xinzhe Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sue E. Crawford
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Rodolfo Moreno
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joanita Jakana
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- CryoEM Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Ramakrishnan Anish
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Soni Kaundal
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mary K Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- CryoEM Core, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Corresponding author. (B.V.V.P.); (Z.W.)
| | - B. V. Venkataram Prasad
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
- Corresponding author. (B.V.V.P.); (Z.W.)
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29
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Differential Localization of Structural and Non-Structural Proteins during the Bluetongue Virus Replication Cycle. Viruses 2020; 12:v12030343. [PMID: 32245145 PMCID: PMC7150864 DOI: 10.3390/v12030343] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/13/2020] [Accepted: 03/19/2020] [Indexed: 12/12/2022] Open
Abstract
Members of the Reoviridae family assemble virus factories within the cytoplasm of infected cells to replicate and assemble virus particles. Bluetongue virus (BTV) forms virus inclusion bodies (VIBs) that are aggregates of viral RNA, certain viral proteins, and host factors, and have been shown to be sites of the initial assembly of transcriptionally active virus-like particles. This study sought to characterize the formation, composition, and ultrastructure of VIBs, particularly in relation to virus replication. In this study we have utilized various microscopic techniques, including structured illumination microscopy, and virological assays to show for the first time that the outer capsid protein VP5, which is essential for virus maturation, is also associated with VIBs. The addition of VP5 to assembled virus cores exiting VIBs is required to arrest transcriptionally active core particles, facilitating virus maturation. Furthermore, we observed a time-dependent association of the glycosylated non-structural protein 3 (NS3) with VIBs, and report on the importance of the two polybasic motifs within NS3 that facilitate virus trafficking and egress from infected cells at the plasma membrane. Thus, the presence of VP5 and the dynamic nature of NS3 association with VIBs that we report here provide novel insight into these previously less well-characterized processes.
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30
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What are the limits of the packaging capacity for genomic RNA in the cores of rotaviruses and of other members of the Reoviridae? Virus Res 2020; 276:197822. [DOI: 10.1016/j.virusres.2019.197822] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 12/16/2022]
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31
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Reoviridae transcription is more than an open-and-shut case. Nat Struct Mol Biol 2019; 26:991-993. [PMID: 31695186 DOI: 10.1038/s41594-019-0328-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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32
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Cui Y, Zhang Y, Zhou K, Sun J, Zhou ZH. Conservative transcription in three steps visualized in a double-stranded RNA virus. Nat Struct Mol Biol 2019; 26:1023-1034. [PMID: 31695188 DOI: 10.1038/s41594-019-0320-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 09/19/2019] [Indexed: 01/28/2023]
Abstract
Endogenous RNA transcription characterizes double-stranded RNA (dsRNA) viruses in the Reoviridae, a family that is exemplified by its simple, single-shelled member cytoplasmic polyhedrosis virus (CPV). Because of the lack of in situ structures of the intermediate stages of RNA-dependent RNA polymerase (RdRp) during transcription, it is poorly understood how RdRp detects environmental cues and internal transcriptional states to initiate and coordinate repeated cycles of transcript production inside the capsid. Here, we captured five high-resolution (2.8-3.5 Å) RdRp-RNA in situ structures-representing quiescent, initiation, early elongation, elongation and abortive states-under seven experimental conditions of CPV. We observed the 'Y'-form initial RNA fork in the initiation state and the complete transcription bubble in the elongation state. These structures reveal that de novo RNA transcription involves three major conformational changes during state transitions. Our results support an ouroboros model for endogenous conservative transcription in dsRNA viruses.
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Affiliation(s)
- Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Yinong Zhang
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.,Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Kang Zhou
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Jingchen Sun
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA. .,Subtropical Sericulture and Mulberry Resources Protection and Safety Engineering Research Center, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China.
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA. .,Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
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