1
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Uprety T, Soni S, Sreenivasan C, Hause BM, Naveed A, Ni S, Graves AJ, Morrow JK, Meade N, Mellits KH, Adam E, Kennedy MA, Wang D, Li F. Genetic and antigenic characterization of two diarrhoeicdominant rotavirus A genotypes G3P[12] and G14P[12] circulating in the global equine population. J Gen Virol 2024; 105:002016. [PMID: 39163114 PMCID: PMC11335307 DOI: 10.1099/jgv.0.002016] [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: 05/31/2024] [Accepted: 07/30/2024] [Indexed: 08/21/2024] Open
Abstract
Equine rotavirus species A (ERVA) G3P[12] and G14P[12] are two dominant genotypes that cause foal diarrhoea with a significant economic impact on the global equine industry. ERVA can also serve as a source of novel (equine-like) rotavirus species A (RVA) reassortants with zoonotic potential as those identified previously in 2013-2019 when equine G3-like RVA was responsible for worldwide outbreaks of severe gastroenteritis and hospitalizations in children. One hurdle to ERVA research is that the standard cell culture system optimized for human rotavirus replication is not efficient for isolating ERVA. Here, using an engineered cell line defective in antiviral innate immunity, we showed that both equine G3P[12] and G14P[12] strains can be rapidly isolated from diarrhoeic foals. The genome sequence analysis revealed that both G3P[12] and G14P[12] strains share the identical genotypic constellation except for VP7 and VP6 segments in which G3P[12] possessed VP7 of genotype G3 and VP6 of genotype I6 and G14P[12] had the combination of VP7 of genotype G14 and VP6 of genotype I2. Further characterization demonstrated that two ERVA genotypes have a limited cross-neutralization. The lack of an in vitro broad cross-protection between both genotypes supported the increased recent diarrhoea outbreaks due to equine G14P[12] in foals born to dams immunized with the inactivated monovalent equine G3P[12] vaccine. Finally, using the structural modelling approach, we provided the genetic basis of the antigenic divergence between ERVA G3P[12] and G14P[12] strains. The results of this study will provide a framework for further investigation of infection biology, pathogenesis and cross-protection of equine rotaviruses.
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Affiliation(s)
- Tirth Uprety
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Shalini Soni
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Chithra Sreenivasan
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Ben M. Hause
- Department of Veterinary and Biomedical Sciences, Animal Disease Research and Diagnostic Laboratory, South Dakota State University, Brookings, South Dakota, 57007, USA
| | - Ahsan Naveed
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Shuisong Ni
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Amy J. Graves
- Equine Diagnostic Solutions, LLC, 1501 Bull Lea Rd, Suite 104, Lexington, Kentucky 40511, USA
| | - Jennifer K. Morrow
- Equine Diagnostic Solutions, LLC, 1501 Bull Lea Rd, Suite 104, Lexington, Kentucky 40511, USA
| | - Nathan Meade
- Division of Microbiology, Brewing, and Biotechnology, School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - Kenneth H. Mellits
- Division of Microbiology, Brewing, and Biotechnology, School of Biosciences, University of Nottingham, Sutton Bonington, UK
| | - Emma Adam
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Michael A. Kennedy
- Department of Veterinary and Biomedical Sciences, Animal Disease Research and Diagnostic Laboratory, South Dakota State University, Brookings, South Dakota, 57007, USA
| | - Dan Wang
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
| | - Feng Li
- Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, Kentucky 40546, USA
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2
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Sinha P, Yadav AK. In silico identification of cyclosporin derivatives as potential inhibitors for RdRp of rotavirus by molecular docking and molecular dynamic studies. J Biomol Struct Dyn 2024; 42:5001-5014. [PMID: 37517053 DOI: 10.1080/07391102.2023.2239918] [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] [Received: 02/21/2023] [Accepted: 06/05/2023] [Indexed: 08/01/2023]
Abstract
Rotavirus is one of the most common gastrointestinal viral diseases. Till date, there are only two vaccines available in the markets, which are specifically to be administered to young babies. In this study, VP1 RdRp is selected as potential target to carry out inhibitory activities. Cyclosporin A (Cys A) derivatives were designed via FBDD, pharmacokinetics, molecular docking, molecular dynamics (MD) simulation and molecular mechanics generalized born surface area was applied on these compounds. The results from these investigations were analyzed and it was found that the considered derivatives in this study were nontoxic and docking results revealed that the derivatives made some important bonds inside the active site of the receptors within a catalytic triad (Serine-Histidine-Aspartate). After analyzing the mean values of root mean square density (RMSD), root mean square fluctuation (RMSF), radius of gyration (RoG) and solvent accessible surface area (SASA) at 100 ns MD simulation of the selected compounds, it was found that compound 1 exhibits RMSD of 0.74 ± 0.10 Å, RMSF of 0.85 ± 0.15 Å, RoG of 16.45 ± 0.40 Å, SASA of 66.55 ± 0.35 nm2 and ΔGbind of -32.76 ± 0.02 kcal/mol. Therefore, the study revealed that amongst the designed and reported compounds, compound 1 was more stable within the active region of the RdRp and also this compound possesses lower binding free energy as compared to other selected compounds and Cys A as well.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Prashasti Sinha
- Department of Physics, School of Physical & Decision Science, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
| | - Anil Kumar Yadav
- Department of Physics, School of Physical & Decision Science, Babasaheb Bhimrao Ambedkar University, Lucknow, Uttar Pradesh, India
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3
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Nichols SL, Haller C, Borodavka A, Esstman SM. Rotavirus NSP2: A Master Orchestrator of Early Viral Particle Assembly. Viruses 2024; 16:814. [PMID: 38932107 PMCID: PMC11209291 DOI: 10.3390/v16060814] [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: 04/18/2024] [Revised: 05/06/2024] [Accepted: 05/16/2024] [Indexed: 06/28/2024] Open
Abstract
Rotaviruses (RVs) are 11-segmented, double-stranded (ds) RNA viruses and important causes of acute gastroenteritis in humans and other animal species. Early RV particle assembly is a multi-step process that includes the assortment, packaging and replication of the 11 genome segments in close connection with capsid morphogenesis. This process occurs inside virally induced, cytosolic, membrane-less organelles called viroplasms. While many viral and cellular proteins play roles during early RV assembly, the octameric nonstructural protein 2 (NSP2) has emerged as a master orchestrator of this key stage of the viral replication cycle. NSP2 is critical for viroplasm biogenesis as well as for the selective RNA-RNA interactions that underpin the assortment of 11 viral genome segments. Moreover, NSP2's associated enzymatic activities might serve to maintain nucleotide pools for use during viral genome replication, a process that is concurrent with early particle assembly. The goal of this review article is to summarize the available data about the structures, functions and interactions of RV NSP2 while also drawing attention to important unanswered questions in the field.
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Affiliation(s)
- Sarah L. Nichols
- Department of Biology, Wake Forest University, Wake Downtown, 455 Vine Street, Winston-Salem, NC 27106, USA;
| | - Cyril Haller
- Department of Chemical Engineering and Biotechnology, Cambridge University, Philippa Fawcett Drive, Cambridge CB3 0AS, UK;
| | - Alexander Borodavka
- Department of Chemical Engineering and Biotechnology, Cambridge University, Philippa Fawcett Drive, Cambridge CB3 0AS, UK;
| | - Sarah M. Esstman
- Department of Biology, Wake Forest University, Wake Downtown, 455 Vine Street, Winston-Salem, NC 27106, USA;
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Kawagishi T, Sánchez-Tacuba L, Feng N, Greenberg HB, Ding S. Reverse Genetics of Murine Rotavirus: A Comparative Analysis of the Wild-Type and Cell-Culture-Adapted Murine Rotavirus VP4 in Replication and Virulence in Neonatal Mice. Viruses 2024; 16:767. [PMID: 38793648 PMCID: PMC11125933 DOI: 10.3390/v16050767] [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: 04/09/2024] [Revised: 05/03/2024] [Accepted: 05/05/2024] [Indexed: 05/26/2024] Open
Abstract
Small-animal models and reverse genetics systems are powerful tools for investigating the molecular mechanisms underlying viral replication, virulence, and interaction with the host immune response in vivo. Rotavirus (RV) causes acute gastroenteritis in many young animals and infants worldwide. Murine RV replicates efficiently in the intestines of inoculated suckling pups, causing diarrhea, and spreads efficiently to uninoculated littermates. Because RVs derived from human and other non-mouse animal species do not replicate efficiently in mice, murine RVs are uniquely useful in probing the viral and host determinants of efficient replication and pathogenesis in a species-matched mouse model. Previously, we established an optimized reverse genetics protocol for RV and successfully generated a murine-like RV rD6/2-2g strain that replicates well in both cultured cell lines and in the intestines of inoculated pups. However, rD6/2-2g possesses three out of eleven gene segments derived from simian RV strains, and these three heterologous segments may attenuate viral pathogenicity in vivo. Here, we rescued the first recombinant RV with all 11 gene segments of murine RV origin. Using this virus as a genetic background, we generated a panel of recombinant murine RVs with either N-terminal VP8* or C-terminal VP5* regions chimerized between a cell-culture-adapted murine ETD strain and a non-tissue-culture-adapted murine EW strain and compared the diarrhea rate and fecal RV shedding in pups. The recombinant viruses with VP5* domains derived from the murine EW strain showed slightly more fecal shedding than those with VP5* domains from the ETD strain. The newly characterized full-genome murine RV will be a useful tool for dissecting virus-host interactions and for studying the mechanism of pathogenesis in neonatal mice.
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Affiliation(s)
- Takahiro Kawagishi
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- VA Palo Alto Health Care System, Department of Veterans Affairs, Palo Alto, CA 94304, USA
| | - Liliana Sánchez-Tacuba
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- VA Palo Alto Health Care System, Department of Veterans Affairs, Palo Alto, CA 94304, USA
| | - Ningguo Feng
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- VA Palo Alto Health Care System, Department of Veterans Affairs, Palo Alto, CA 94304, USA
| | - Harry B. Greenberg
- Department of Medicine, Division of Gastroenterology and Hepatology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- VA Palo Alto Health Care System, Department of Veterans Affairs, Palo Alto, CA 94304, USA
| | - Siyuan Ding
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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5
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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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6
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de Sautu M, Herrmann T, Scanavachi G, Jenni S, Harrison SC. The rotavirus VP5*/VP8* conformational transition permeabilizes membranes to Ca2. PLoS Pathog 2024; 20:e1011750. [PMID: 38574119 PMCID: PMC11020617 DOI: 10.1371/journal.ppat.1011750] [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: 10/16/2023] [Revised: 04/16/2024] [Accepted: 03/04/2024] [Indexed: 04/06/2024] Open
Abstract
Rotaviruses infect cells by delivering into the cytosol a transcriptionally active inner capsid particle (a "double-layer particle": DLP). Delivery is the function of a third, outer layer, which drives uptake from the cell surface into small vesicles from which the DLPs escape. In published work, we followed stages of rhesus rotavirus (RRV) entry by live-cell imaging and correlated them with structures from cryogenic electron microscopy and tomography (cryo-EM and cryo-ET). The virus appears to wrap itself in membrane, leading to complete engulfment and loss of Ca2+ from the vesicle produced by the wrapping. One of the outer-layer proteins, VP7, is a Ca2+-stabilized trimer; loss of Ca2+ releases both VP7 and the other outer-layer protein, VP4, from the particle. VP4, activated by cleavage into VP8* and VP5*, is a trimer that undergoes a large-scale conformational rearrangement, reminiscent of the transition that viral fusion proteins undergo to penetrate a membrane. The rearrangement of VP5* thrusts a 250-residue, C-terminal segment of each of the three subunits outward, while allowing the protein to remain attached to the virus particle and to the cell being infected. We proposed that this segment inserts into the membrane of the target cell, enabling Ca2+ to cross. In the work reported here, we show the validity of key aspects of this proposed sequence. By cryo-EM studies of liposome-attached virions ("triple-layer particles": TLPs) and single-particle fluorescence imaging of liposome-attached TLPs, we confirm insertion of the VP4 C-terminal segment into the membrane and ensuing generation of a Ca2+ "leak". The results allow us to formulate a molecular description of early events in entry. We also discuss our observations in the context of other work on double-strand RNA virus entry.
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Affiliation(s)
- Marilina de Sautu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Tobias Herrmann
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gustavo Scanavachi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stephen C. Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts, United States of America
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7
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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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Anderson ML, Sullivan OM, Nichols SL, Kaylor L, Kelly DF, McDonald Esstman S. Rotavirus core shell protein sites that regulate intra-particle polymerase activity. J Virol 2023; 97:e0086023. [PMID: 37830817 PMCID: PMC10617381 DOI: 10.1128/jvi.00860-23] [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: 06/06/2023] [Accepted: 09/06/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE Rotaviruses are important causes of severe gastroenteritis in young children. A characteristic feature of rotaviruses is that they copy ribonucleic acid (RNA) inside of the viral particle. In fact, the viral polymerase (VP1) only functions when it is connected to the viral inner core shell protein (VP2). Here, we employed a biochemical assay to identify which sites of VP2 are critical for regulating VP1 activity. Specifically, we engineered VP2 proteins to contain amino acid changes at structurally defined sites and assayed them for their capacity to support VP1 function in a test tube. Through this work, we were able to identify several VP2 residues that appeared to regulate the activity of the polymerase, positively and negatively. These results are important because they help explain how rotavirus synthesizes its RNA while inside of particles and they identify targets for the future rational design of drugs to prevent rotavirus disease.
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Affiliation(s)
| | - Owen M. Sullivan
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Sarah L. Nichols
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Liam Kaylor
- Department of Biomedical Engineering, State University, University Park, Pennsylvania, USA
| | - Deborah F. Kelly
- Department of Biomedical Engineering, State University, University Park, Pennsylvania, USA
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9
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De Sautu M, Herrmann T, Jenni S, Harrison SC. The rotavirus VP5*/VP8* conformational transition permeabilizes membranes to Ca 2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.15.562449. [PMID: 37905109 PMCID: PMC10614792 DOI: 10.1101/2023.10.15.562449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Rotaviruses infect cells by delivering into the cytosol a transcriptionally active inner capsid particle (a "double-layer particle": DLP). Delivery is the function of a third, outer layer, which drives uptake from the cell surface into small vesicles from which the DLPs escape. In published work, we followed stages of rhesus rotavirus (RRV) entry by live-cell imaging and correlated them with structures from cryogenic electron microscopy and tomography (cryo-EM and cryo-ET). The virus appears to wrap itself in membrane, leading to complete engulfment and loss of Ca2+ from the vesicle produced by the wrapping. One of the outer-layer proteins, VP7, is a Ca2+-stabilized trimer; loss of Ca2+ releases both outer-layer proteins from the particle. The other outer-layer protein, VP4, activated by cleavage into VP8* and VP5*, is a trimer that undergoes a large-scale conformational rearrangement, reminiscent of the transition that viral fusion proteins undergo to penetrate a membrane. The rearrangement of VP5* thrusts a 250-residue, C-terminal segment of each of the three subunits outward, while allowing the protein to remain attached to the virus particle and to the cell being infected. We proposed that this segment inserts into the membrane of the target cell, enabling Ca2+ to cross. In the work reported here, we show the validity of key aspects of this proposed sequence. By cryo-EM studies of liposome-attached virions ("triple-layer particles": TLPs) and single-particle fluorescence imaging of liposome-attached TLPs, we confirm insertion of the VP4 C-terminal segment into the membrane and ensuing generation of a Ca2+ "leak". The results allow us to formulate a molecular description of early events in entry. We also discuss our observations in the context of other work on double-strand RNA virus entry.
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Affiliation(s)
- Marilina De Sautu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Tobias Herrmann
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Stephen C. Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
- Laboratory of Molecular Medicine, Boston Children’s Hospital, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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10
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Asensio-Cob D, Rodríguez JM, Luque D. Rotavirus Particle Disassembly and Assembly In Vivo and In Vitro. Viruses 2023; 15:1750. [PMID: 37632092 PMCID: PMC10458742 DOI: 10.3390/v15081750] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/11/2023] [Accepted: 08/14/2023] [Indexed: 08/27/2023] Open
Abstract
Rotaviruses (RVs) are non-enveloped multilayered dsRNA viruses that are major etiologic agents of diarrheal disease in humans and in the young in a large number of animal species. The viral particle is composed of three different protein layers that enclose the segmented dsRNA genome and the transcriptional complexes. Each layer defines a unique subparticle that is associated with a different phase of the replication cycle. Thus, while single- and double-layered particles are associated with the intracellular processes of selective packaging, genome replication, and transcription, the viral machinery necessary for entry is located in the third layer. This modular nature of its particle allows rotaviruses to control its replication cycle by the disassembly and assembly of its structural proteins. In this review, we examine the significant advances in structural, molecular, and cellular RV biology that have contributed during the last few years to illuminating the intricate details of the RV particle disassembly and assembly processes.
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Affiliation(s)
- Dunia Asensio-Cob
- Department of Molecular Medicine, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G0A4, Canada;
| | - Javier M. Rodríguez
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología/CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Daniel Luque
- Electron Microscopy Unit UCCT/ISCIII, 28220 Majadahonda, Spain
- School of Biomedical Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
- Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW 2052, Australia
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11
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Fernandez de la Mora J, Almazán F, Rodríguez JM. Spontaneous Interconversion between Different Narrowly Defined Shapes of Rotavirus Double-Layered Particles Studied in Real Time by High-Resolution Mobility Analysis. Anal Chem 2023; 95:11483-11490. [PMID: 37463035 DOI: 10.1021/acs.analchem.3c01994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Rotavirus double-layered particles (DLPs) are studied in the gas phase with a high-resolution differential mobility analyzer (DMA). DLPs were transferred to 10 mM aqueous ammonium acetate, electrosprayed into the gas phase, converted into primarily singly charged particles, and DMA-analyzed. Up to seven slightly different conformations were resolved, whose apparently random, fast (minutes), and reversible interconversions were followed in real time. They sometimes evolved into just two distinct structures, with periods of one dominating over the other and vice versa. Differences between the DLP structures in solution and in the gas phase are clearly revealed by the smaller DLP diameter found here (60 versus 70 nm). Nevertheless, we argue that the multiple gas-phase conformers observed originate in as many conformations pre-existing in solution. We further hypothesize that these conformers correspond to incomplete DLPs having lost some of the VP6 trimer quintets surrounding each of the 12 5-fold axes. Instances of this peculiar loss have been previously documented by cryoelectron microscopy for the rotavirus Wa strain, as well as via charge detection mass spectrometry for five other rotavirus strains included in the RotaTec vaccine. Evidence of this loss systematically found for all 7 rotavirus types so far studied in aqueous ammonium acetate may be a special feature of this electrolyte.
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Affiliation(s)
- Juan Fernandez de la Mora
- Department of Mechanical Engineering and Materials Science, Yale University, 9 Hillhouse Avenue, New Haven, Connecticut 06520-8286, United States
| | - Fernando Almazán
- Department of Cellular and Molecular Biology, Centro Nacional de Biotecnología (CNB), CSIC, Darwin 3, 28049 Madrid, Spain
| | - Javier M Rodríguez
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB), CSIC, Darwin 3, 28049 Madrid, Spain
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12
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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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13
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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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14
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Flexibility of the Rotavirus NSP2 C-Terminal Region Supports Factory Formation via Liquid-Liquid Phase Separation. J Virol 2023; 97:e0003923. [PMID: 36749077 PMCID: PMC9973012 DOI: 10.1128/jvi.00039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Many viruses sequester the materials needed for their replication into discrete subcellular factories. For rotaviruses (RVs), these factories are called viroplasms, and they are formed in the host cell cytosol via the process of liquid-liquid phase separation (LLPS). The nonstructural protein 2 (NSP2) and its binding partner, nonstructural protein 5 (NSP5), are critical for viroplasm biogenesis. Yet it is not fully understood how NSP2 and NSP5 cooperate to form factories. The C-terminal region (CTR) of NSP2 (residues 291 to 317) is flexible, allowing it to participate in domain-swapping interactions that promote interoctamer interactions and, presumably, viroplasm formation. Molecular dynamics simulations showed that a lysine-to-glutamic acid change at position 294 (K294E) reduces NSP2 CTR flexibility in silico. To test the impact of reduced NSP2 CTR flexibility during infection, we engineered a mutant RV bearing this change (rRV-NSP2K294E). Single-cycle growth assays revealed a >1.2-log reduction in endpoint titers for rRV-NSP2K294E versus the wild-type control (rRV-WT). Using immunofluorescence assays, we found that rRV-NSP2K294E formed smaller, more numerous viroplasms than rRV-WT. Live-cell imaging experiments confirmed these results and revealed that rRV-NSP2K294E factories had delayed fusion kinetics. Moreover, NSP2K294E and several other CTR mutants formed fewer viroplasm-like structures in NSP5 coexpressing cells than did control NSP2WT. Finally, NSP2K294E exhibited defects in its capacity to induce LLPS droplet formation in vitro when incubated alongside NSP5. These results underscore the importance of NSP2 CTR flexibility in supporting the biogenesis of RV factories. IMPORTANCE Viruses often condense the materials needed for their replication into discrete intracellular factories. For rotaviruses, agents of severe gastroenteritis in children, factory formation is mediated in part by an octameric protein called NSP2. A flexible C-terminal region of NSP2 has been proposed to link several NSP2 octamers together, a feature that might be important for factory formation. Here, we created a change in NSP2 that reduced C-terminal flexibility and analyzed the impact on rotavirus factories. We found that the change caused the formation of smaller and more numerous factories that could not readily fuse together like those of the wild-type virus. The altered NSP2 protein also had a reduced capacity to form factory-like condensates in a test tube. Together, these results add to our growing understanding of how NSP2 supports rotavirus factory formation-a key step of viral replication.
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15
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Anderson ML, McDonald Esstman S. In vitro particle-associated uridyltransferase activity of the rotavirus VP1 polymerase. Virology 2022; 577:24-31. [PMID: 36257129 PMCID: PMC10728782 DOI: 10.1016/j.virol.2022.09.015] [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: 08/29/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022]
Abstract
Rotaviruses are 11-segmented, double-stranded RNA (dsRNA) viruses with a unique intra-particle RNA synthesis mechanism. During genome replication, the RNA-dependent RNA polymerase (VP1) performs minus-strand RNA (-ssRNA) synthesis on positive-strand RNA (+ssRNA) templates to create dsRNA segments. Recombinant VP1 catalyzes -ssRNA synthesis using substrate NTPs in vitro, but only when the VP2 core shell protein or virus-like particles made of VP2 and VP6 (2/6-VLPs) are included in the reaction. The dsRNA product can be labeled using [α32P]-UTP and separated from the input +ssRNA template by polyacrylamide gel electrophoresis. Here, we report the generation of [α32P]-labeled rotavirus +ssRNA templates in reactions that lacked non-radiolabeled NTPs but contained catalytically-active VP1, 2/6-VLPs, and [α32P]-UTP. Non-radiolabeled UTP competed with [α32P]-UTP to decrease product levels, whereas CTP and GTP had little effect. Interesting, ATP stimulated [α32P]-labeled product production. These results suggest that rotavirus VP1 transferred [α32P]-UMP onto viral + ssRNA in vitro via a particle-associated uridyltransferase activity.
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16
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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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17
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Revisiting Viral RNA-Dependent RNA Polymerases: Insights from Recent Structural Studies. Viruses 2022; 14:v14102200. [PMID: 36298755 PMCID: PMC9612308 DOI: 10.3390/v14102200] [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: 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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18
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Mature Rotavirus Particles Contain Equivalent Amounts of 7meGpppG-Capped and Noncapped Viral Positive-Sense RNAs. J Virol 2022; 96:e0115122. [PMID: 36000838 PMCID: PMC9472601 DOI: 10.1128/jvi.01151-22] [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: 11/20/2022] Open
Abstract
Viruses have evolved different strategies to overcome their recognition by the host innate immune system. The addition of caps at their 5' RNA ends is an efficient mechanism not only to ensure escape from detection by the innate immune system but also to ensure the efficient synthesis of viral proteins. Rotavirus mRNAs contain a type 1 cap structure at their 5' end that is added by the viral capping enzyme VP3, which is a multifunctional protein with all the enzymatic activities necessary to add the cap and also functions as an antagonist of the 2'-5'-oligoadenylate synthetase (OAS)/RNase L pathway. Here, the relative abundances of capped and noncapped viral RNAs during the replication cycle of rotavirus were determined. We found that both classes of rotaviral plus-sense RNAs (+RNAs) were encapsidated and that they were present in a 1:1 ratio in the mature infectious particles. The capping of viral +RNAs was dynamic, since different ratios of capped and noncapped RNAs were detected at different times postinfection. Similarly, when the relative amounts of capped and uncapped viral +RNAs produced in an in vitro transcription system were determined, we found that the proportions were very similar to those in the mature viral particles and in infected cells, suggesting that the capping efficiency of VP3, both in vivo and in vitro, might be close to 50%. Unexpectedly, when the effect of simultaneously knocking down the expression of VP3 and RNase L on the cap status of viral +RNAs was evaluated, we found that, even though at late times postinfection there was an increased proportion of capped viral RNAs in infected cells, the viral particles isolated from this condition contained equal ratios of capped and noncapped viral RNA, suggesting that there might be selective packaging of capped and noncapped RNAs. IMPORTANCE Rotaviruses have a genome composed of 11 segments of double-stranded RNA. Whether all 5' ends of the positive-sense genomic RNAs contained in the mature viral particles are modified by a cap structure is unknown. In this work, we characterized the relative proportions of capped and noncapped viral RNAs in rotavirus-infected cells and in viral particles by using a direct quantitative assay. We found that, independent of the relative proportions of capped/noncapped RNAs present in rotavirus-infected cells, there were similar proportions of these two kinds of 5'-modified positive-sense RNAs in the viral particles.
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19
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Rotavirus VP4 Epitope of a Broadly Neutralizing Human Antibody Defined by Its Structure Bound with an Attenuated-Strain Virion. J Virol 2022; 96:e0062722. [PMID: 35924923 PMCID: PMC9400500 DOI: 10.1128/jvi.00627-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rotavirus live-attenuated vaccines, both mono- and pentavalent, generate broadly heterotypic protection. B-cells isolated from adults encode neutralizing antibodies, some with affinity for VP5*, that afford broad protection in mice. We have mapped the epitope of one such antibody by determining the high-resolution cryo-EM structure of its antigen-binding fragment (Fab) bound to the virion of a candidate vaccine strain, CDC-9. The Fab contacts both the distal end of a VP5* β-barrel domain and the two VP8* lectin-like domains at the tip of a projecting spike. Its interactions with VP8* do not impinge on the likely receptor-binding site, suggesting that the mechanism of neutralization is at a step subsequent to initial attachment. We also examined structures of CDC-9 virions from two different stages of serial passaging. Nearly all the VP4 (cleaved to VP8*/VP5*) spikes on particles from the earlier passage (wild-type isolate) had transitioned from the "upright" conformation present on fully infectious virions to the "reversed" conformation that is probably the end state of membrane insertion, unable to mediate penetration, consistent with the very low in vitro infectivity of the wild-type isolate. About half the VP4 spikes were upright on particles from the later passage, which had recovered substantial in vitro infectivity but had acquired an attenuated phenotype in neonatal rats. A mutation in VP4 that occurred during passaging appears to stabilize the interface at the apex of the spike and could account for the greater stability of the upright spikes on the late-passage, attenuated isolate. IMPORTANCE Rotavirus live-attenuated vaccines generate broadly heterotypic protection, and B-cells isolated from adults encode antibodies that are broadly protective in mice. Determining the structural and mechanistic basis of broad protection can contribute to understanding the current limitations of vaccine efficacy in developing countries. The structure of an attenuated human rotavirus isolate (CDC-9) bound with the Fab fragment of a broadly heterotypic protective antibody shows that protection is probably due to inhibition of the conformational transition in the viral spike protein (VP4) critical for viral penetration, rather than to inhibition of receptor binding. A comparison of structures of CDC-9 virus particles at two stages of serial passaging supports a proposed mechanism for initial steps in rotavirus membrane penetration.
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20
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Jenni S, Horwitz JA, Bloyet LM, Whelan SPJ, Harrison SC. Visualizing molecular interactions that determine assembly of a bullet-shaped vesicular stomatitis virus particle. Nat Commun 2022; 13:4802. [PMID: 35970826 PMCID: PMC9378655 DOI: 10.1038/s41467-022-32223-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/18/2022] [Indexed: 11/09/2022] Open
Abstract
Vesicular stomatitis virus (VSV) is a negative-strand RNA virus with a non-segmented genome, closely related to rabies virus. Both have characteristic bullet-like shapes. We report the structure of intact, infectious VSV particles determined by cryogenic electron microscopy. By compensating for polymorphism among viral particles with computational classification, we obtained a reconstruction of the shaft ("trunk") at 3.5 Å resolution, with lower resolution for the rounded tip. The ribonucleoprotein (RNP), genomic RNA complexed with nucleoprotein (N), curls into a dome-like structure with about eight gradually expanding turns before transitioning into the regular helical trunk. Two layers of matrix (M) protein link the RNP with the membrane. Radial inter-layer subunit contacts are fixed within single RNA-N-M1-M2 modules, but flexible lateral and axial interactions allow assembly of polymorphic virions. Together with published structures of recombinant N in various states, our results suggest a mechanism for membrane-coupled self-assembly of VSV and its relatives.
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Affiliation(s)
- Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
| | - Joshua A Horwitz
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA
- Molecular Pharmacology and Virology Group, PureTech Health LLC, Boston, MA, 02210, USA
| | - Louis-Marie Bloyet
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Sean P J Whelan
- Department of Microbiology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, 02115, USA.
- Laboratory of Molecular Medicine, Boston Children's Hospital, Boston, MA, 02115, USA.
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21
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Ogino M, Green TJ, Ogino T. GDP polyribonucleotidyltransferase domain of vesicular stomatitis virus polymerase regulates leader-promoter escape and polyadenylation-coupled termination during stop-start transcription. PLoS Pathog 2022; 18:e1010287. [PMID: 35108335 PMCID: PMC8843114 DOI: 10.1371/journal.ppat.1010287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 02/14/2022] [Accepted: 01/19/2022] [Indexed: 11/23/2022] Open
Abstract
The unconventional mRNA capping enzyme (GDP polyribonucleotidyltransferase, PRNTase) domain of the vesicular stomatitis virus (VSV) L protein possesses a dual-functional "priming-capping loop" that governs terminal de novo initiation for leader RNA synthesis and capping of monocistronic mRNAs during the unique stop-start transcription cycle. Here, we investigated the roles of basic amino acid residues on a helix structure directly connected to the priming-capping loop in viral RNA synthesis and identified single point mutations that cause previously unreported defective phenotypes at different steps of stop-start transcription. Mutations of residue R1183 (R1183A and R1183K) dramatically reduced the leader RNA synthesis activity by hampering early elongation, but not terminal de novo initiation or productive elongation, suggesting that the mutations negatively affect escape from the leader promoter. On the other hand, mutations of residue R1178 (R1178A and R1178K) decreased the efficiency of polyadenylation-coupled termination of mRNA synthesis at the gene junctions, but not termination of leader RNA synthesis at the leader-to-N-gene junction, resulting in the generation of larger amounts of aberrant polycistronic mRNAs. In contrast, both the R1183 and R1178 residues are not essential for cap-forming activities. The R1183K mutation was lethal to VSV, whereas the R1178K mutation attenuated VSV and triggered the production of the polycistronic mRNAs in infected cells. These observations suggest that the PRNTase domain plays multiple roles in conducting accurate stop-start transcription beyond its known role in pre-mRNA capping. Vesicular stomatitis virus (VSV), an animal rhabdovirus closely related to rabies virus, has served as a paradigm for understanding the basic molecular mechanisms of transcription and replication by rhabdoviruses (e.g., rabies) and other non-segmented negative strand (NNS) RNA viruses, such as measles and Ebola. NNS RNA viral polymerases sequentially synthesize the non-coding leader RNA and monocistronic mRNAs from the 3′-terminal leader region and internal genes, respectively, on their genomes by the stop-start transcription mechanism. A hallmark of NNS RNA viral polymerases is the presence of a unique enzymatic domain, called GDP polyribonucleotidyltransferase (PRNTase), which catalyzes pre-mRNA 5′-capping, one of the essential mRNA modifications. Our recent study revealed that the VSV PRNTase domain directs transcription initiation at the 3′-end of the genome as well as pre-mRNA capping with the dual functional priming-capping loop during stop-start transcription. Here, we further show that a helix structure flanked by the priming-capping loop regulates not only transcription elongation at an early phase of leader RNA synthesis but also polyadenylation-coupled transcription termination at gene junctions. These findings indicate that the PRNTase domain acts as a key regulatory domain for stop-start transcription as well as a catalytic domain for pre-mRNA capping.
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Affiliation(s)
- Minako Ogino
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Todd J. Green
- Department of Microbiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Tomoaki Ogino
- Department of Medical Microbiology and Immunology, College of Medicine and Life Sciences, University of Toledo, Toledo, Ohio, United States of America
- * E-mail:
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22
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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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23
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Caddy S, Papa G, Borodavka A, Desselberger U. Rotavirus research: 2014-2020. Virus Res 2021; 304:198499. [PMID: 34224769 DOI: 10.1016/j.virusres.2021.198499] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 02/09/2023]
Abstract
Rotaviruses are major causes of acute gastroenteritis in infants and young children worldwide and also cause disease in the young of many other mammalian and of avian species. During the recent 5-6 years rotavirus research has benefitted in a major way from the establishment of plasmid only-based reverse genetics systems, the creation of human and other mammalian intestinal enteroids, and from the wide application of structural biology (cryo-electron microscopy, cryo-EM tomography) and complementary biophysical approaches. All of these have permitted to gain new insights into structure-function relationships of rotaviruses and their interactions with the host. This review follows different stages of the viral replication cycle and summarizes highlights of structure-function studies of rotavirus-encoded proteins (both structural and non-structural), molecular mechanisms of viral replication including involvement of cellular proteins and lipids, the spectrum of viral genomic and antigenic diversity, progress in understanding of innate and acquired immune responses, and further developments of prevention of rotavirus-associated disease.
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Affiliation(s)
- Sarah Caddy
- Cambridge Institute for Therapeutic Immunology and Infectious Disease Jeffery Cheah Biomedical Centre, Cambridge, CB2 0AW, UK.
| | - Guido Papa
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Alexander Borodavka
- Department of Biochemistry, University of Cambridge, Cambridge, CB2 1QW, UK.
| | - Ulrich Desselberger
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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24
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Nilsson EM, Sullivan OM, Anderson ML, Argobright HM, Shue TM, Fedowitz FR, LaConte LEW, Esstman SM. Reverse genetic engineering of simian rotaviruses with temperature-sensitive lesions in VP1, VP2, and VP6. Virus Res 2021; 302:198488. [PMID: 34146610 DOI: 10.1016/j.virusres.2021.198488] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 05/24/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
Rotaviruses are 11-segmented double-stranded RNA viruses and important causes of acute gastroenteritis in young children. To investigate the functions of specific viral proteins during the rotavirus lifecycle, temperature-sensitive (ts) mutants were previously created using a cultivatable simian strain (SA11) and chemical mutagenesis. These ts SA11 mutants replicate more efficiently at the permissive temperature of 31 °C than at the non-permissive temperature of 39 °C. Prototype strains SA11-tsC, SA11-tsF, and SA11-tsG were mapped to the genes encoding structural proteins VP1, VP2, and VP6, respectively, and putative ts lesions were identified using Sanger sequencing. However, additional background mutations in their genomes had hampered validation of the ts lesions and confounded their use in mechanistic studies. Here, we employed plasmid only-based reverse genetics to engineer recombinant (r) SA11 rotaviruses containing only the putative ts lesions of SA11-tsC (L138P change in VP1), SA11-tsF (A387D change in VP2) or SA11-tsG (S10T, D13H, and A121G changes in VP6). For simplicity, we refer to these newly-engineered, isogenic viruses as rSA11-tsVP1, rSA11-tsVP2, and rSA11-tsVP6. Single-cycle growth assays revealed that these mutants indeed exhibit ts phenotypes with significantly diminished titers (>1.5-logs) at 39 °C versus 31 °C. The rSA11 ts mutants proved genetically stable at the population-level following 3 sequential passages at 39 °C, but individual revertant clones were detected in plaque assays. Heat sensitivity experiments showed that pre-incubation of rSA11-tsVP1 or rSA11-tsVP2, but not rSA11-tsVP6, at 39 °C diminished replication at 31 °C. This result indicates that the ts lesions in VP1 and VP2 affect the incoming virion but those in VP6 affect a later stage of the viral lifecycle. In silico molecular dynamics simulations predicted temperature-dependent, long-range effects of the S10T, D13H, and/or A121G changes on the VP6 structure. Altogether, our results confirm the ts lesions of the original SA11-tsC, SA11-tsF, and SA11-tsG mutants, provide a new set of isogenic strains for investigating aspects of rotavirus replication, and shed light on how the ts lesions might impact VP1, VP2, or VP6 functions.
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Affiliation(s)
- Emil M Nilsson
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
| | - Owen M Sullivan
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
| | | | | | - Taylor M Shue
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
| | | | - Leslie E W LaConte
- Fralin Biomedical Research Institute, Roanoke, VA, USA; Department of Basic Science Education, Virginia Tech Carilion School of Medicine, Roanoke, VA, USA
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25
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Abstract
Group A rotaviruses (RVAs) are the major cause of severe acute gastroenteritis (AGE) in children under 5 years of age, annually resulting in nearly 130,000 deaths worldwide. Social conditions in developing countries that contribute to decreased oral rehydration and vaccine efficacy and the lack of approved antiviral drugs position RVA as a global health concern. In this minireview, we present an update in the field of antiviral compounds, mainly in relation to the latest findings in RVA virion structure and the viral replication cycle. In turn, we attempt to provide a perspective on the possible treatments for RVA-associated AGE, with special focus on novel approaches, such as those representing broad-spectrum therapeutic options. In this context, the modulation of host factors, lipid droplets, and the viral polymerase, which is highly conserved among AGE-causing viruses, are analyzed as possible drug targets.
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26
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Smith SC, Gribble J, Diller JR, Wiebe MA, Thoner TW, Denison MR, Ogden KM. Reovirus RNA recombination is sequence directed and generates internally deleted defective genome segments during passage. J Virol 2021; 95:JVI.02181-20. [PMID: 33472930 PMCID: PMC8103698 DOI: 10.1128/jvi.02181-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/14/2021] [Indexed: 12/12/2022] Open
Abstract
For viruses with segmented genomes, genetic diversity is generated by genetic drift, reassortment, and recombination. Recombination produces RNA populations distinct from full-length gene segments and can influence viral population dynamics, persistence, and host immune responses. Viruses in the Reoviridae family, including rotavirus and mammalian orthoreovirus (reovirus), have been reported to package segments containing rearrangements or internal deletions. Rotaviruses with RNA segments containing rearrangements have been isolated from immunocompromised and immunocompetent children and in vitro following serial passage at relatively high multiplicity. Reoviruses that package small, defective RNA segments have established chronic infections in cells and in mice. However, the mechanism and extent of Reoviridae RNA recombination are undefined. Towards filling this gap in knowledge, we determined the titers and RNA segment profiles for reovirus and rotavirus following serial passage in cultured cells. The viruses exhibited occasional titer reductions characteristic of interference. Reovirus strains frequently accumulated segments that retained 5' and 3' terminal sequences and featured large internal deletions, while similarly fragmented segments were rarely detected in rotavirus populations. Using next-generation RNA-sequencing to analyze RNA molecules packaged in purified reovirus particles, we identified distinct recombination sites within individual viral genome segments. Recombination junctions were frequently but not always characterized by short direct sequence repeats upstream and downstream that spanned junction sites. Taken together, these findings suggest that reovirus accumulates defective gene segments featuring internal deletions during passage and undergoes sequence-directed recombination at distinct sites.IMPORTANCE Viruses in the Reoviridae family include important pathogens of humans and other animals and have segmented RNA genomes. Recombination in RNA virus populations can facilitate novel host exploration and increased disease severity. The extent, patterns, and mechanisms of Reoviridae recombination and the functions and effects of recombined RNA products are poorly understood. Here, we provide evidence that mammalian orthoreovirus regularly synthesizes RNA recombination products that retain terminal sequences but contain internal deletions, while rotavirus rarely synthesizes such products. Recombination occurs more frequently at specific sites in the mammalian orthoreovirus genome, and short regions of identical sequence are often detected at junction sites. These findings suggest that mammalian orthoreovirus recombination events are directed in part by RNA sequences. An improved understanding of recombined viral RNA synthesis may enhance our capacity to engineer improved vaccines and virotherapies in the future.
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Affiliation(s)
- Sydni Caet Smith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center
| | - Jennifer Gribble
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center
| | - Julia R Diller
- Department of Pediatrics, Vanderbilt University Medical Center
| | - Michelle A Wiebe
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center
| | - Timothy W Thoner
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center
| | - Mark R Denison
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center
- Department of Pediatrics, Vanderbilt University Medical Center
| | - Kristen M Ogden
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center
- Department of Pediatrics, Vanderbilt University Medical Center
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27
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Herrmann T, Torres R, Salgado EN, Berciu C, Stoddard D, Nicastro D, Jenni S, Harrison SC. Functional refolding of the penetration protein on a non-enveloped virus. Nature 2021; 590:666-670. [PMID: 33442061 PMCID: PMC8297411 DOI: 10.1038/s41586-020-03124-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/08/2020] [Indexed: 11/09/2022]
Abstract
A non-enveloped virus requires a membrane lesion to deliver its genome into a target cell1. For rotaviruses, membrane perforation is a principal function of the viral outer-layer protein, VP42,3. Here we describe the use of electron cryomicroscopy to determine how VP4 performs this function and show that when activated by cleavage to VP8* and VP5*, VP4 can rearrange on the virion surface from an 'upright' to a 'reversed' conformation. The reversed structure projects a previously buried 'foot' domain outwards into the membrane of the host cell to which the virion has attached. Electron cryotomograms of virus particles entering cells are consistent with this picture. Using a disulfide mutant of VP4, we have also stabilized a probable intermediate in the transition between the two conformations. Our results define molecular mechanisms for the first steps of the penetration of rotaviruses into the membranes of target cells and suggest similarities with mechanisms postulated for other viruses.
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Affiliation(s)
- Tobias Herrmann
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.,Graduate Program in Virology, Harvard Medical School, Boston, MA, USA
| | - Raúl Torres
- Laboratory of Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Eric N Salgado
- Laboratory of Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.,Seqirus USA, Cambridge, MA, USA
| | - Cristina Berciu
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, MA, USA.,Microscopy Core Facility, McLean Hospital, Belmont, MA, USA
| | - Daniel Stoddard
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, MA, USA.,Department of Cell Biology, University of Texas Southwestern, Dallas, TX, USA
| | - Daniela Nicastro
- Rosenstiel Basic Medical Sciences Research Center, Department of Biology, Brandeis University, Waltham, MA, USA.,Department of Cell Biology, University of Texas Southwestern, Dallas, TX, USA
| | - Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA. .,Laboratory of Molecular Medicine, Boston Children's Hospital, Boston, MA, USA. .,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA, USA.
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28
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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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29
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Chávez-Maya F, García-Espinosa G, López-Arellano ME, Padilla-Noriega L. Mutations in the VP2 gene of rotavirus associated with benzimidazole sensitivity. Virus Res 2020; 291:198189. [PMID: 33049307 DOI: 10.1016/j.virusres.2020.198189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/23/2020] [Accepted: 10/05/2020] [Indexed: 12/15/2022]
Abstract
Rotavirus species A (RVA) is the etiological agent of acute gastroenteritis in young individuals of various animal species, including humans. Vaccination has helped to reduce the impact of these viruses on humans and some species of domestic mammals, but they do not confer complete immunity, so antirotavirus agents are another important control option. In this study, millimolar concentrations of benzimidazole inhibited the replication of the Rhesus rotavirus (RRV) strain of RVA. Two mutants partially resistant to the inhibitory effect of benzimidazole were independently selected, and their genomes and those of their parental strains were fully sequenced. Most (7/11) mutations occurred in the gene that encodes the VP2 protein, and similarly most of the missense mutations (5/9), including the only one shared by the two mutants (G2,414 → R[G/A], D800 N), occurred in the VP2 gene. Our results identify the VP2 gene as the primary target affected by benzimidazole.
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Affiliation(s)
- Fernando Chávez-Maya
- Departamento de Medicina y Zootecnia de Aves, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Coyoacán 04510, Ciudad de México, Mexico.
| | - Gary García-Espinosa
- Departamento de Medicina y Zootecnia de Aves, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Coyoacán 04510, Ciudad de México, Mexico.
| | - María Eugenia López-Arellano
- Departamento de Helmintología, Centro Nacional de Investigación Disciplinaria en Salud Animal e Inocuidad, INIFAP-México, Jiutepec 62550, Morelos, Mexico.
| | - Luis Padilla-Noriega
- Departamento de Microbiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, edificio A, primer piso, Coyoacán 04510, Ciudad de México, Mexico.
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30
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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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31
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Sutton G, Sun D, Fu X, Kotecha A, Hecksel CW, Clare DK, Zhang P, Stuart DI, Boyce M. Assembly intermediates of orthoreovirus captured in the cell. Nat Commun 2020; 11:4445. [PMID: 32895380 PMCID: PMC7477198 DOI: 10.1038/s41467-020-18243-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/08/2020] [Indexed: 12/03/2022] Open
Abstract
Traditionally, molecular assembly pathways for viruses are inferred from high resolution structures of purified stable intermediates, low resolution images of cell sections and genetic approaches. Here, we directly visualise an unsuspected 'single shelled' intermediate for a mammalian orthoreovirus in cryo-preserved infected cells, by cryo-electron tomography of cellular lamellae. Particle classification and averaging yields structures to 5.6 Å resolution, sufficient to identify secondary structural elements and produce an atomic model of the intermediate, comprising 120 copies each of protein λ1 and σ2. This λ1 shell is 'collapsed' compared to the mature virions, with molecules pushed inwards at the icosahedral fivefolds by ~100 Å, reminiscent of the first assembly intermediate of certain prokaryotic dsRNA viruses. This supports the supposition that these viruses share a common ancestor, and suggests mechanisms for the assembly of viruses of the Reoviridae. Such methodology holds promise for dissecting the replication cycle of many viruses.
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Affiliation(s)
- Geoff Sutton
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
| | - Dapeng Sun
- Department of Structure Biology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Xiaofeng Fu
- Department of Structure Biology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Abhay Kotecha
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK
- Thermo Fisher Scientific, Achtseweg Noorg 5, 5651 GG, Eindhoven, The Netherlands
| | - Corey W Hecksel
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA, 94025, USA
| | - Daniel K Clare
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Department of Structure Biology, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
| | - David I Stuart
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
- Diamond Light Source Limited, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK.
| | - Mark Boyce
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, OX3 7BN, UK.
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32
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Liang C, Tian L, Liu Y, Hui N, Qiao G, Li H, Shi Z, Tang Y, Zhang D, Xie X, Zhao X. A promising antiviral candidate drug for the COVID-19 pandemic: A mini-review of remdesivir. Eur J Med Chem 2020; 201:112527. [PMID: 32563812 PMCID: PMC7834743 DOI: 10.1016/j.ejmech.2020.112527] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/14/2020] [Accepted: 06/01/2020] [Indexed: 02/08/2023]
Abstract
Remdesivir (GS-5734), a viral RNA-dependent RNA polymerase (RdRP) inhibitor that can be used to treat a variety of RNA virus infections, is expected to be an effective treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. On May 1, 2020, The U.S. Food and Drug Administration (FDA) has granted Emergency Use Authorization (EUA) for remdesivir to treat COVID-19 patients. In light of the COVID-19 pandemic, this review presents comprehensive information on remdesivir, including information regarding the milestones, intellectual properties, anti-coronavirus mechanisms, preclinical research and clinical trials, and in particular, the chemical synthesis, pharmacology, toxicology, pharmacodynamics and pharmacokinetics of remdesivir. Furthermore, perspectives regarding the use of remdesivir for the treatment of COVID-19 are also discussed.
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Affiliation(s)
- Chengyuan Liang
- School of Food and Bioengineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China.
| | - Lei Tian
- School of Food and Bioengineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Yuzhi Liu
- School of Food and Bioengineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Nan Hui
- School of Food and Bioengineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Guaiping Qiao
- School of Food and Bioengineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Han Li
- School of Food and Bioengineering, Shaanxi University of Science & Technology, Xi'an, 710021, PR China
| | - Zhenfeng Shi
- Department of Urology Surgery Center, The People's Hospital of Xinjiang Uyghur Autonomous Region, Urumqi, 830002, PR China
| | - Yonghong Tang
- Xi'an Taikomed Pharmaceutical Technology Co., Ltd., Xi'an, 710077, PR China
| | - Dezhu Zhang
- Shaanxi Panlong Pharmaceutical Group Co., Ltd., Xi'an, 710025, PR China
| | - Xiaolin Xie
- Shaanxi Panlong Pharmaceutical Group Co., Ltd., Xi'an, 710025, PR China
| | - Xu Zhao
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, 200040, PR China.
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33
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Abid N, Pietrucci D, Salemi M, Chillemi G. New Insights into the Effect of Residue Mutations on the Rotavirus VP1 Function Using Molecular Dynamic Simulations. J Chem Inf Model 2020; 60:5011-5025. [PMID: 32786703 DOI: 10.1021/acs.jcim.0c00475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rotavirus group A remains a major cause of diarrhea in infants and young children worldwide. The permanent emergence of new genotypes puts the potential effectiveness of vaccines under serious questions. Thirteen VP1 structures with mutations mapping to the RNA entry site were analyzed using molecular dynamics simulations, and the results were combined with the experimental findings reported previously. The results revealed structural fluctuations in the protein-protein recognition sites and in the bottleneck of the RNA entry site that may affect the interaction of different proteins and delay the initiation of the viral replication, respectively. Altogether, the structural analysis of VP1 in the region crucial for the initiation of the viral replication, mainly the bottleneck site, may boost efforts to develop antivirals, as they might complement the available vaccines.
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Affiliation(s)
- Nabil Abid
- Laboratory of Transmissible Diseases and Biological Active Substances LR99ES27, Faculty of Pharmacy, University of Monastir, Rue Ibn Sina, 5000 Monastir, Tunisia.,High Institute of Biotechnology of Sidi Thabet, Department of Biotechnology, University Manouba, BP-66, 2020 Ariana-Tunis, Tunisia
| | - Daniele Pietrucci
- Department of Biology, University of Rome Tor Vergata, Via Della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Marco Salemi
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Emerging Pathogens Institute, University of Florida, P.O. Box 100009, Gainesville, Florida 32610-3633, United States
| | - Giovanni Chillemi
- Department for Innovation in Biological, Agro-Food and Forest Systems, DIBAF, University of Tuscia, Via S. Camillo de Lellis s.n.c., 01100 Viterbo, Italy.,Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, IBIOM, CNR, Via Giovanni Amendola, 122/O, 70126 Bari, Italy
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34
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Brown ML, Sullivan OM, McDonald Esstman S. A Perfect Ten-Decoy Maps Uncover Polymerase Complexes within Reoviridae Virion. Structure 2020; 28:595-597. [PMID: 32492410 DOI: 10.1016/j.str.2020.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
In this issue of Structure, Kaelber et al. (2020) use cryo-EM and synthetic decoy maps to reveal the patterning of 10 polymerase complexes within FAKV, a Reoviridae family member containing 9 genome segments. Their findings support a model for FAKV assembly that has implications for the entire Reoviridae family.
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Affiliation(s)
- Mackenzie L Brown
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
| | - Owen M Sullivan
- Department of Biology, Wake Forest University, Winston-Salem, NC, USA
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35
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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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36
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Conserved Rotavirus NSP5 and VP2 Domains Interact and Affect Viroplasm. J Virol 2020; 94:JVI.01965-19. [PMID: 31915278 DOI: 10.1128/jvi.01965-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 12/21/2019] [Indexed: 01/15/2023] Open
Abstract
One step of the life cycle common to all rotaviruses (RV) studied so far is the formation of viroplasms, membrane-less cytosolic inclusions providing a microenvironment for early morphogenesis and RNA replication. Viroplasm-like structures (VLS) are simplified viroplasm models consisting of complexes of nonstructural protein 5 (NSP5) with the RV core shell VP2 or NSP2. We identified and characterized the domains required for NSP5-VP2 interaction and VLS formation. VP2 mutations L124A, V865A, and I878A impaired both NSP5 hyperphosphorylation and NSP5/VP2 VLS formation. Moreover, NSP5-VP2 interaction does not depend on NSP5 hyperphosphorylation. The NSP5 tail region is required for VP2 interaction. Notably, VP2 L124A expression acts as a dominant-negative element by disrupting the formation of either VLS or viroplasms and blocking RNA synthesis. In silico analyses revealed that VP2 L124, V865, and I878 are conserved among RV species A to H. Detailed knowledge of the protein interaction interface required for viroplasm formation may facilitate the design of broad-spectrum antivirals to block RV replication.IMPORTANCE Alternative treatments to combat rotavirus infection are a requirement for susceptible communities where vaccines cannot be applied. This demand is urgent for newborn infants, immunocompromised patients, adults traveling to high-risk regions, and even for the livestock industry. Aside from structural and physiological divergences among RV species studied before now, all replicate within cytosolic inclusions termed viroplasms. These inclusions are composed of viral and cellular proteins and viral RNA. Viroplasm-like structures (VLS), composed of RV protein NSP5 with either NSP2 or VP2, are models for investigating viroplasms. In this study, we identified a conserved amino acid in the VP2 protein, L124, necessary for its interaction with NSP5 and the formation of both VLSs and viroplasms. As RV vaccines cover a narrow range of viral strains, the identification of VP2 L124 residue lays the foundations for the design of drugs that specifically block NSP5-VP2 interaction as a broad-spectrum RV antiviral.
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37
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Jenni S, Bloyet LM, Diaz-Avalos R, Liang B, Whelan SPJ, Grigorieff N, Harrison SC. Structure of the Vesicular Stomatitis Virus L Protein in Complex with Its Phosphoprotein Cofactor. Cell Rep 2020; 30:53-60.e5. [PMID: 31914397 PMCID: PMC7049099 DOI: 10.1016/j.celrep.2019.12.024] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 11/22/2019] [Accepted: 12/06/2019] [Indexed: 11/15/2022] Open
Abstract
The large (L) proteins of non-segmented, negative-strand RNA viruses are multifunctional enzymes that produce capped, methylated, and polyadenylated mRNA and replicate the viral genome. A phosphoprotein (P), required for efficient RNA-dependent RNA polymerization from the viral ribonucleoprotein (RNP) template, regulates the function and conformation of the L protein. We report the structure of vesicular stomatitis virus L in complex with its P cofactor determined by electron cryomicroscopy at 3.0 Å resolution, enabling us to visualize bound segments of P. The contacts of three P segments with multiple L domains show how P induces a closed, compact, initiation-competent conformation. Binding of P to L positions its N-terminal domain adjacent to a putative RNA exit channel for efficient encapsidation of newly synthesized genomes with the nucleoprotein and orients its C-terminal domain to interact with an RNP template. The model shows that a conserved tryptophan in the priming loop can support the initiating 5' nucleotide.
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Affiliation(s)
- Simon Jenni
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Louis-Marie Bloyet
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ruben Diaz-Avalos
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Bo Liang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Sean P J Whelan
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA; Department of Molecular Microbiology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Nikolaus Grigorieff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Stephen C Harrison
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
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38
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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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39
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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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40
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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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41
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Hauser M, Dearnaley WJ, Varano AC, Casasanta M, McDonald SM, Kelly DF. Cryo-EM Reveals Architectural Diversity in Active Rotavirus Particles. Comput Struct Biotechnol J 2019; 17:1178-1183. [PMID: 31467657 PMCID: PMC6710475 DOI: 10.1016/j.csbj.2019.07.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 12/04/2022] Open
Abstract
Rotavirus is a well-studied RNA virus that causes severe gastroenteritis in children. During viral entry, the outer layer of the virion is shed, creating a double-layered particle (DLP) that is competent to perform viral transcription (i.e., mRNA synthesis) and launch infection. While inactive forms of rotavirus DLPs have been structurally characterized in detail, information about the transcriptionally-active DLP remains limited. Here, we used cryo-Electron Microscopy (cryo-EM) and 3D image reconstructions to compare the structures of internal protein components in transcriptionally-active versus inactive DLPs. Our findings showed that transcriptionally-active DLPs gained internal order as mRNA synthesis unfolded, while inactive DLPs remained dynamically disordered. Regions of viral protein/RNA constituents were analyzed across two different axes of symmetry to provide a more comprehensive view of moving components. Taken together, our results bring forth a new view of active DLPs, which may enable future pharmacological strategies aimed at obliterating rotavirus transcription as a therapeutic approach.
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Affiliation(s)
| | - William J. Dearnaley
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
- Center for Structural Oncology, Pennsylvania State University, University Park, PA 16802, USA
| | - A. Cameron Varano
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
- Center for Structural Oncology, Pennsylvania State University, University Park, PA 16802, USA
| | - Michael Casasanta
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
- Center for Structural Oncology, Pennsylvania State University, University Park, PA 16802, USA
| | - Sarah M. McDonald
- Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA
| | - Deborah F. Kelly
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA 16802, USA
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
- Center for Structural Oncology, Pennsylvania State University, University Park, PA 16802, USA
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42
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In situ structures of RNA-dependent RNA polymerase inside bluetongue virus before and after uncoating. Proc Natl Acad Sci U S A 2019; 116:16535-16540. [PMID: 31350350 DOI: 10.1073/pnas.1905849116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bluetongue virus (BTV), a major threat to livestock, is a multilayered, nonturreted member of the Reoviridae, a family of segmented dsRNA viruses characterized by endogenous RNA transcription through an RNA-dependent RNA polymerase (RdRp). To date, the structure of BTV RdRp has been unknown, limiting our mechanistic understanding of BTV transcription and hindering rational drug design effort targeting this essential enzyme. Here, we report the in situ structures of BTV RdRp VP1 in both the triple-layered virion and double-layered core, as determined by cryo-electron microscopy (cryoEM) and subparticle reconstruction. BTV RdRp has 2 unique motifs not found in other viral RdRps: a fingernail, attached to the conserved fingers subdomain, and a bundle of 3 helices: 1 from the palm subdomain and 2 from the N-terminal domain. BTV RdRp VP1 is anchored to the inner surface of the capsid shell via 5 asymmetrically arranged N termini of the inner capsid shell protein VP3A around the 5-fold axis. The structural changes of RdRp VP1 and associated capsid shell proteins between BTV virions and cores suggest that the detachment of the outer capsid proteins VP2 and VP5 during viral entry induces both global movements of the inner capsid shell and local conformational changes of the N-terminal latch helix (residues 34 to 51) of 1 inner capsid shell protein VP3A, priming RdRp VP1 within the capsid for transcription. Understanding this mechanism in BTV also provides general insights into RdRp activation and regulation during viral entry of other multilayered, nonturreted dsRNA viruses.
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