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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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Durinova E, Mojzes P, Bily T, Franta Z, Fessl T, Borodavka A, Tuma R. Shedding light on reovirus assembly-Multimodal imaging of viral factories. Adv Virus Res 2023; 116:173-213. [PMID: 37524481 DOI: 10.1016/bs.aivir.2023.06.002] [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: 08/02/2023]
Abstract
Avian (ortho)reovirus (ARV), which belongs to Reoviridae family, is a major domestic fowl pathogen and is the causative agent of viral tenosynovitis and chronic respiratory disease in chicken. ARV replicates within cytoplasmic inclusions, so-called viral factories, that form by phase separation and thus belong to a wider class of biological condensates. Here, we evaluate different optical imaging methods that have been developed or adapted to follow formation, fluidity and composition of viral factories and compare them with the complementary structural information obtained by well-established transmission electron microscopy and electron tomography. The molecular and cellular biology aspects for setting up and following virus infection in cells by imaging are described first. We then demonstrate that a wide-field version of fluorescence recovery after photobleaching is an effective tool to measure fluidity of mobile viral factories. A new technique, holotomographic phase microscopy, is then used for imaging of viral factory formation in live cells in three dimensions. Confocal Raman microscopy of infected cells provides "chemical" contrast for label-free segmentation of images and addresses important questions about biomolecular concentrations within viral factories and other biological condensates. Optical imaging is complemented by electron microscopy and tomography which supply higher resolution structural detail, including visualization of individual virions within the three-dimensional cellular context.
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Affiliation(s)
- Eva Durinova
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Peter Mojzes
- Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
| | - Tomas Bily
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic; Biology Centre, Czech Academy of Sciences, Ceske Budejovice, Czech Republic
| | - Zdenek Franta
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Tomas Fessl
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic
| | - Alexander Borodavka
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Roman Tuma
- Faculty of Science, University of South Bohemia, Ceske Budejovice, Czech Republic.
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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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Desselberger U. 14th International dsRNA Virus Symposium, Banff, Alberta, Canada, 10-14 October 2022. Virus Res 2023; 324:199032. [PMID: 36584760 DOI: 10.1016/j.virusres.2022.199032] [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: 11/30/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/29/2022]
Abstract
This triennial International dsRNA Virus Symposium covered original data which have accrued during the most recent five years. In detail, the genomic diversity of these viruses continued to be explored; various structure-function studies were carried out using reverse genetics and biophysical techniques; intestinal organoids proved to be very suitable for special pathogenesis studies; and the potential of next generation rotavirus vaccines including use of rotavirus recombinants as vectored vaccine candidates was explored. 'Non-lytic release of enteric viruses in cloaked vesicles' was the topic of the keynote lecture by Nihal Altan-Bonnet, NIH, Bethesda, USA. The Jean Cohen lecturer of this meeting was Polly Roy, London School of Hygiene and Tropical Medicine, who spoke on aspects of the replication cycle of bluetongue viruses, and how some of the data are similar to details of rotavirus replication.
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Affiliation(s)
- Ulrich Desselberger
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, U.K..
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Rahman SK, Ampah KK, Roy P. Role of NS2 specific RNA binding and phosphorylation in liquid-liquid phase separation and virus assembly. Nucleic Acids Res 2022; 50:11273-11284. [PMID: 36259663 DOI: 10.1093/nar/gkac904] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/28/2022] [Accepted: 10/08/2022] [Indexed: 11/13/2022] Open
Abstract
Liquid-liquid phase separation (LLPS) has assumed a prominent role in biological cell systems, where it underpins the formation of subcellular compartments necessary for cell function. We investigated the underlying mechanism of LLPS in virus infected cells, where virus inclusion bodies are formed by an RNA-binding phosphoprotein (NS2) of Bluetongue virus to serve as sites for subviral particle assembly and virus maturation. We show that NS2 undergoes LLPS that is dependent on protein phosphorylation and RNA-binding and that LLPS occurrence is accompanied by a change in protein secondary structure. Site-directed mutagenesis identified two critical arginine residues in NS2 responsible for specific RNA binding and thus for NS2-RNA complex driven LLPS. Reverse genetics identified the same residues as essential for VIB assembly in infected cells and virus viability. Our findings suggest that a specific arginine-RNA interaction in the context of a phosphorylated state drives LLPS in this, and possibly other, virus infections.
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Affiliation(s)
- Shah Kamranur Rahman
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT UK
| | - Khamal Kwesi Ampah
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT UK
| | - Polly Roy
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT UK
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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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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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Kopanke J, Lee J, Stenglein M, Mayo C. In Vitro Reassortment between Endemic Bluetongue Viruses Features Global Shifts in Segment Frequencies and Preferred Segment Combinations. Microorganisms 2021; 9:microorganisms9020405. [PMID: 33669284 PMCID: PMC7920030 DOI: 10.3390/microorganisms9020405] [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: 01/25/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023] Open
Abstract
Bluetongue virus (BTV) is an arthropod-borne pathogen that is associated with sometimes severe disease in both domestic and wild ruminants. Predominantly transmitted by Culicoides spp. biting midges, BTV is composed of a segmented, double-stranded RNA genome. Vector expansion and viral genetic changes, such as reassortment between BTV strains, have been implicated as potential drivers of ongoing BTV expansion into previously BTV-free regions. We used an in vitro system to investigate the extent and flexibility of reassortment that can occur between two BTV strains that are considered enzootic to the USA, BTV-2 and BTV-10. Whole genome sequencing (WGS) was coupled with plaque isolation and a novel, amplicon-based sequencing approach to quantitate the viral genetic diversity generated across multiple generations of in vitro propagation. We found that BTV-2 and BTV-10 were able to reassort across multiple segments, but that a preferred BTV-2 viral backbone emerged in later passages and that certain segments were more likely to be found in reassortant progeny. Our findings indicate that there may be preferred segment combinations that emerge during BTV reassortment. Moreover, our work demonstrates the usefulness of WGS and amplicon-based sequencing approaches to improve understanding of the dynamics of reassortment among segmented viruses such as BTV.
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Marín-López A, Barreiro-Piñeiro N, Utrilla-Trigo S, Barriales D, Benavente J, Nogales A, Martínez-Costas J, Ortego J, Calvo-Pinilla E. Cross-protective immune responses against African horse sickness virus after vaccination with protein NS1 delivered by avian reovirus muNS microspheres and modified vaccinia virus Ankara. Vaccine 2019; 38:882-889. [PMID: 31708178 DOI: 10.1016/j.vaccine.2019.10.087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/15/2019] [Accepted: 10/25/2019] [Indexed: 01/01/2023]
Abstract
African horse sickness virus (AHSV) is an insect-borne pathogen that causes acute disease in horses and other equids. In an effort to improve the safety of currently available vaccines and to acquire new knowledge about the determinants of AHSV immunogenicity, new generation vaccines are being developed. In this work we have generated and tested a novel immunization approach comprised of nonstructural protein 1 (NS1) of AHSV serotype 4 (AHSV-4) incorporated into avian reovirus muNS protein microspheres (MS-NS1) and/or expressed using recombinant modified vaccinia virus Ankara vector (MVA-NS1). The protection conferred against AHSV by a homologous MS-NS1 or heterologous MS-NS1 and MVA-NS1 prime/boost was evaluated in IFNAR (-/-) mice. Our results indicate that immunization based on MS-NS1 and MVA-NS1 afforded complete protection against the infection with homologous AHSV-4. Moreover, priming with MS-NS1 and boost vaccination with MVA-NS1 (MS-MVA-NS1) triggered NS1 specific cytotoxic CD8 + T cells and prevented AHSV disease in IFNAR (-/-) mice after challenge with heterologous serotype AHSV-9. Cross-protective immune responses are highly important since AHS can be caused by nine different serotypes, which means that a universal polyvalent vaccination would need to induce protective immunity against all serotypes.
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Affiliation(s)
- Alejandro Marín-López
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain
| | - Natalia Barreiro-Piñeiro
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), and Departamento de Bioquímica e Bioloxía Molecular, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Sergio Utrilla-Trigo
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain
| | - Diego Barriales
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain
| | - Javier Benavente
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), and Departamento de Bioquímica e Bioloxía Molecular, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Aitor Nogales
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain
| | - José Martínez-Costas
- Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CIQUS), and Departamento de Bioquímica e Bioloxía Molecular, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Javier Ortego
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain.
| | - Eva Calvo-Pinilla
- Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, Centro de Investigación en Sanidad Animal (INIA-CISA), Madrid, Spain
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Newburn LR, White KA. Trans-Acting RNA-RNA Interactions in Segmented RNA Viruses. Viruses 2019; 11:v11080751. [PMID: 31416187 PMCID: PMC6723669 DOI: 10.3390/v11080751] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 08/08/2019] [Accepted: 08/11/2019] [Indexed: 12/18/2022] Open
Abstract
RNA viruses represent a large and important group of pathogens that infect a broad range of hosts. Segmented RNA viruses are a subclass of this group that encode their genomes in two or more molecules and package all of their RNA segments in a single virus particle. These divided genomes come in different forms, including double-stranded RNA, coding-sense single-stranded RNA, and noncoding single-stranded RNA. Genera that possess these genome types include, respectively, Orbivirus (e.g., Bluetongue virus), Dianthovirus (e.g., Red clover necrotic mosaic virus) and Alphainfluenzavirus (e.g., Influenza A virus). Despite their distinct genomic features and diverse host ranges (i.e., animals, plants, and humans, respectively) each of these viruses uses trans-acting RNA–RNA interactions (tRRIs) to facilitate co-packaging of their segmented genome. The tRRIs occur between different viral genome segments and direct the selective packaging of a complete genome complement. Here we explore the current state of understanding of tRRI-mediated co-packaging in the abovementioned viruses and examine other known and potential functions for this class of RNA–RNA interaction.
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Affiliation(s)
- Laura R Newburn
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada
| | - K Andrew White
- Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
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