1
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Hacker C, Sendra K, Keisham P, Filipescu T, Lucocq J, Salimi F, Ferguson S, Bhella D, MacNeill SA, Embley M, Lucocq J. Biogenesis, inheritance, and 3D ultrastructure of the microsporidian mitosome. Life Sci Alliance 2024; 7:e202201635. [PMID: 37903625 PMCID: PMC10618108 DOI: 10.26508/lsa.202201635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 11/01/2023] Open
Abstract
During the reductive evolution of obligate intracellular parasites called microsporidia, a tiny remnant mitochondrion (mitosome) lost its typical cristae, organellar genome, and most canonical functions. Here, we combine electron tomography, stereology, immunofluorescence microscopy, and bioinformatics to characterise mechanisms of growth, division, and inheritance of this minimal mitochondrion in two microsporidia species (grown within a mammalian RK13 culture-cell host). Mitosomes of Encephalitozoon cuniculi (2-12/cell) and Trachipleistophora hominis (14-18/nucleus) displayed incremental/non-phasic growth and division and were closely associated with an organelle identified as equivalent to the fungal microtubule-organising centre (microsporidian spindle pole body; mSPB). The mitosome-mSPB association was resistant to treatment with microtubule-depolymerising drugs nocodazole and albendazole. Dynamin inhibitors (dynasore and Mdivi-1) arrested mitosome division but not growth, whereas bioinformatics revealed putative dynamins Drp-1 and Vps-1, of which, Vps-1 rescued mitochondrial constriction in dynamin-deficient yeast (Schizosaccharomyces pombe). Thus, microsporidian mitosomes undergo incremental growth and dynamin-mediated division and are maintained through ordered inheritance, likely mediated via binding to the microsporidian centrosome (mSPB).
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Affiliation(s)
- Christian Hacker
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - Kacper Sendra
- Biosciences Institute, The Medical School, Catherine Cookson Building, Newcastle University, Newcastle upon Tyne, UK
| | - Priyanka Keisham
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - Teodora Filipescu
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - James Lucocq
- Department of Surgery, Dundee Medical School Ninewells Hospital, Dundee, UK
| | - Fatemeh Salimi
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - Sophie Ferguson
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Stuart A MacNeill
- https://ror.org/02wn5qz54 School of Biology, University of St Andrews, St Andrews, UK
| | - Martin Embley
- Biosciences Institute, Centre for Bacterial Cell Biology, Baddiley-Clark Building, Newcastle University, Newcastle upon Tyne, UK
| | - John Lucocq
- https://ror.org/02wn5qz54 School of Medicine, University of St Andrews, St Andrews, UK
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2
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Weckener M, Woodward LS, Clarke BR, Liu H, Ward PN, Le Bas A, Bhella D, Whitfield C, Naismith JH. The lipid linked oligosaccharide polymerase Wzy and its regulating co-polymerase, Wzz, from enterobacterial common antigen biosynthesis form a complex. Open Biol 2023; 13:220373. [PMID: 36944376 PMCID: PMC10030265 DOI: 10.1098/rsob.220373] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/27/2023] [Indexed: 03/23/2023] Open
Abstract
The enterobacterial common antigen (ECA) is a carbohydrate polymer that is associated with the cell envelope in the Enterobacteriaceae. ECA contains a repeating trisaccharide which is polymerized by WzyE, a member of the Wzy membrane protein polymerase superfamily. WzyE activity is regulated by a membrane protein polysaccharide co-polymerase, WzzE. Förster resonance energy transfer experiments demonstrate that WzyE and WzzE from Pectobacterium atrosepticum form a complex in vivo, and immunoblotting and cryo-electron microscopy (cryo-EM) analysis confirm a defined stoichiometry of approximately eight WzzE to one WzyE. Low-resolution cryo-EM reconstructions of the complex, aided by an antibody recognizing the C-terminus of WzyE, reveals WzyE sits in the central membrane lumen formed by the octameric arrangement of the transmembrane helices of WzzE. The pairing of Wzy and Wzz is found in polymerization systems for other bacterial polymers, including lipopolysaccharide O-antigens and capsular polysaccharides. The data provide new structural insight into a conserved mechanism for regulating polysaccharide chain length in bacteria.
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Affiliation(s)
- Miriam Weckener
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Laura S. Woodward
- Centre Biomedical Sciences, North Haugh, University of St Andrews, St Andrews KY16 9ST, UK
| | - Bradley R. Clarke
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada
| | - Huanting Liu
- Centre Biomedical Sciences, North Haugh, University of St Andrews, St Andrews KY16 9ST, UK
| | - Philip N. Ward
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Audrey Le Bas
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - David Bhella
- MRC—University of Glasgow Centre for Virus Research, University of Glasgow, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1Q, UK
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, The University of Guelph, Guelph, ON, Canada
| | - James H. Naismith
- Structural Biology, The Rosalind Franklin Institute, Harwell Campus, Didcot OX11 0QS, UK
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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3
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Bakker SE, Bhella D, Brescia R, Bullough P, Clare DK, Daum B, Frank RAW, Gold VAM, Jackson Hirst I, Kühlbrandt W, Lu P, McLaren M, Menday R, Muench SP, Rauschenbach S, Russo CJ, Saibil H, Scheres SHW, Shah AR, Smith C, Torpey J, Zanetti G. Pushing the limits in single particle cryo-EM: general discussion. Faraday Discuss 2022; 240:312-322. [PMID: 36285779 DOI: 10.1039/d2fd90063g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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4
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Al-Otaibi N, Baatsen P, Bhella D, Brescia R, Bullough P, Daum B, de Bruin R, Frank R, Kühlbrandt W, López-Iglesias C, McLaren M, Menday R, Morrissey F, Mullick D, Paris G, Parker A, Russo C, Saibil H, Scheres SHW, Shah A, Smith C, Thompson R, Thorn A, Zanetti G, Zhao J. Tomographic analysis, CLEM: general discussion. Faraday Discuss 2022; 240:142-151. [PMID: 36282233 DOI: 10.1039/d2fd90060b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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5
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Bakker SE, Bergeron J, Bharadwaj A, Bhella D, Bullough P, Chau PL, Frank RAW, Jakobi AJ, Joseph AP, Kühlbrandt W, Lahiri I, Menday R, Muench SP, Nakasone M, Nerukh D, Paris G, Russo CJ, Saibil HR, Scheres SHW, Sehrawat V, Shah AR, Thorn A, Vilas JL, Zanetti G. Map/model validation and machine learning in EM: general discussion. Faraday Discuss 2022; 240:229-242. [PMID: 36254744 DOI: 10.1039/d2fd90061k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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6
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Al-Otaibi N, Aminian J A, Anane RF, Baatsen P, Bakker SE, Bergeron J, Bharadwaj A, Bhella D, Braun T, Brescia R, Bullough P, Clare DK, Daum B, Esser TK, Farinas Lucas IDM, Frank RAW, Gold VAM, Harrison PJ, Hirst IJ, Klebl DP, Kühlbrandt W, Morton C, Muench SP, Nakasone M, Russo CJ, Saibil HR, Scheres SHW, Sehrawat V, Shah AR, Smith C, Thompson RF, Thorn A, Zanetti G. Sample preparation in single particle cryo-EM: general discussion. Faraday Discuss 2022; 240:81-100. [PMID: 36278863 DOI: 10.1039/d2fd90059a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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7
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Conley MJ, Short JM, Burns AM, Streetley J, Hutchings J, Bakker SE, Power BJ, Jaffery H, Haney J, Zanetti G, Murcia PR, Stewart M, Fearns R, Vijayakrishnan S, Bhella D. Helical ordering of envelope-associated proteins and glycoproteins in respiratory syncytial virus. EMBO J 2022; 41:e109728. [PMID: 34935163 PMCID: PMC8804925 DOI: 10.15252/embj.2021109728] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 12/01/2021] [Accepted: 12/03/2021] [Indexed: 12/20/2022] Open
Abstract
Human respiratory syncytial virus (RSV) causes severe respiratory illness in children and the elderly. Here, using cryogenic electron microscopy and tomography combined with computational image analysis and three-dimensional reconstruction, we show that there is extensive helical ordering of the envelope-associated proteins and glycoproteins of RSV filamentous virions. We calculated a 16 Å resolution sub-tomogram average of the matrix protein (M) layer that forms an endoskeleton below the viral envelope. These data define a helical lattice of M-dimers, showing how M is oriented relative to the viral envelope. Glycoproteins that stud the viral envelope were also found to be helically ordered, a property that was coordinated by the M-layer. Furthermore, envelope glycoproteins clustered in pairs, a feature that may have implications for the conformation of fusion (F) glycoprotein epitopes that are the principal target for vaccine and monoclonal antibody development. We also report the presence, in authentic virus infections, of N-RNA rings packaged within RSV virions. These data provide molecular insight into the organisation of the virion and the mechanism of its assembly.
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Affiliation(s)
- Michaela J Conley
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Judith M Short
- Medical Research Council Laboratory of Molecular BiologyCambridgeUK
| | - Andrew M Burns
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - James Streetley
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Joshua Hutchings
- Department of Biological SciencesBirkbeck CollegeLondonUK
- Present address:
Division of Biological SciencesUniversity of California San DiegoLa JollaCAUSA
| | - Saskia E Bakker
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
- Present address:
School of Life SciencesUniversity of WarwickCoventryUK
| | - B Joanne Power
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
- Present address:
Department of Biochemistry and Molecular BiologyThe Huck Center for Malaria ResearchPennsylvania State UniversityUniversity ParkPAUSA
| | - Hussain Jaffery
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Joanne Haney
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Giulia Zanetti
- Department of Biological SciencesBirkbeck CollegeLondonUK
| | - Pablo R Murcia
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Murray Stewart
- Medical Research Council Laboratory of Molecular BiologyCambridgeUK
| | - Rachel Fearns
- Department of MicrobiologyBoston University School of MedicineBostonMAUSA
- National Emerging Infectious Diseases LaboratoriesBoston UniversityBostonMAUSA
| | | | - David Bhella
- Medical Research Council – University of Glasgow Centre for Virus ResearchGlasgowUK
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8
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Mahindra A, Tejeda G, Rossi M, Janha O, Herbert I, Morris C, Morgan DC, Beattie W, Montezano AC, Hudson B, Tobin AB, Bhella D, Touyz RM, Jamieson AG, Baillie GS, Blair CM. Peptides derived from the SARS-CoV-2 receptor binding motif bind to ACE2 but do not block ACE2-mediated host cell entry or pro-inflammatory cytokine induction. PLoS One 2021; 16:e0260283. [PMID: 34793553 PMCID: PMC8601423 DOI: 10.1371/journal.pone.0260283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/05/2021] [Indexed: 11/19/2022] Open
Abstract
SARS-CoV-2 viral attachment and entry into host cells is mediated by a direct interaction between viral spike glycoproteins and membrane bound angiotensin-converting enzyme 2 (ACE2). The receptor binding motif (RBM), located within the S1 subunit of the spike protein, incorporates the majority of known ACE2 contact residues responsible for high affinity binding and associated virulence. Observation of existing crystal structures of the SARS-CoV-2 receptor binding domain (SRBD)-ACE2 interface, combined with peptide array screening, allowed us to define a series of linear native RBM-derived peptides that were selected as potential antiviral decoy sequences with the aim of directly binding ACE2 and attenuating viral cell entry. RBM1 (16mer): S443KVGGNYNYLYRLFRK458, RBM2A (25mer): E484GFNCYFPLQSYGFQPTNGVGYQPY508, RBM2B (20mer): F456NCYFPLQSYGFQPTNGVGY505 and RBM2A-Sc (25mer): NYGLQGSPFGYQETPYPFCNFVQYG. Data from fluorescence polarisation experiments suggested direct binding between RBM peptides and ACE2, with binding affinities ranging from the high nM to low μM range (Kd = 0.207-1.206 μM). However, the RBM peptides demonstrated only modest effects in preventing SRBD internalisation and showed no antiviral activity in a spike protein trimer neutralisation assay. The RBM peptides also failed to suppress S1-protein mediated inflammation in an endogenously expressing ACE2 human cell line. We conclude that linear native RBM-derived peptides are unable to outcompete viral spike protein for binding to ACE2 and therefore represent a suboptimal approach to inhibiting SARS-CoV-2 viral cell entry. These findings reinforce the notion that larger biologics (such as soluble ACE2, 'miniproteins', nanobodies and antibodies) are likely better suited as SARS-CoV-2 cell-entry inhibitors than short-sequence linear peptides.
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Affiliation(s)
- Amit Mahindra
- School of Chemistry, University of Glasgow, Glasgow, United Kingdom
| | - Gonzalo Tejeda
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Mario Rossi
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, L’Aquila, Italy
| | - Omar Janha
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Imogen Herbert
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - Caroline Morris
- School of Chemistry, University of Glasgow, Glasgow, United Kingdom
| | | | - Wendy Beattie
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Augusto C. Montezano
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Brian Hudson
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew B. Tobin
- Institute of Molecular Cell & Systems Biology, School of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - David Bhella
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - Rhian M. Touyz
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - George S. Baillie
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Connor M. Blair
- Institute of Cardiovascular and Medical Sciences, Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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9
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Plucinski A, Pavlovic M, Clarke M, Bhella D, Schmidt BVKJ. Stimuli-Responsive Aggregation of High Molar Mass Poly(N,N-Diethylacrylamide)-b-Poly(4-Acryloylmorpholine) in Tetrahydrofuran. Macromol Rapid Commun 2021; 43:e2100656. [PMID: 34783099 DOI: 10.1002/marc.202100656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/10/2021] [Indexed: 02/01/2023]
Abstract
The self-assembly of block copolymers constitutes a timely research area in polymer science with implications for applications like sensing or drug-delivery. Here, the unprecedented aggregation behavior of high molar mass block copolymer poly(N,N-diethylacrylamide)-b-poly(4-acryloylmorpholine) (PDEA-b-PAM) (Mn >400 kg mol-1 ) in organic solvent tetrahydrofuran (THF) is investigated. To elucidate the aggregation, dynamic light scattering, cryo-transmission electron microscopy, and turbidimetry are employed. The aggregate formation is assigned to the unprecedented upper critical solution temperature behavior of PAM in THF at elevated concentrations (> 6 wt.%) and high molar masses. Various future directions for this new thermo-responsive block copolymer are envisioned, for example, in the areas of photonics or templating of inorganic structures.
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Affiliation(s)
| | - Marko Pavlovic
- Department of Colloid Chemistry, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, Potsdam, 14476, Germany.,BioSense Institute, University of Novi Sad, Dr Zorana Djindjica 1, III-8, Novi Sad, 21000, Serbia
| | - Mairi Clarke
- Scottish Centre for Macromolecular Imaging, University of Glasgow, Glasgow, G61 1QH, UK
| | - David Bhella
- Scottish Centre for Macromolecular Imaging, University of Glasgow, Glasgow, G61 1QH, UK
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10
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Montezano AC, Camargo L, Mary S, Neves KB, Rios FJ, Alves-lopes R, Beattie W, Herbert I, Herder V, Szemiel AM, McFarlane S, Palmarini M, Bhella D, Touyz RM. Abstract 40: SARS-CoV-2/ACE2 Induces Vascular Inflammatory Responses In Human Microvascular Endothelial Cells Independently Of Viral Replication. Hypertension 2021. [DOI: 10.1161/hyp.78.suppl_1.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
SARS-CoV-2, the virus responsible for COVID19, binds to ACE2, via its spike protein S1 subunit, leading to viral infection and respiratory disease. COVID-19 is associated with cardiovascular disease and systemic inflammation. Since ACE2 is expressed in vascular cells we questioned whether SARS-CoV-2 induces vascular inflammation and whether this is related to viral infection. Human microvascular endothelial cells (EC) were exposed to recombinant S1p (rS1p) 0.66 μg/mL for 10 min, 5h and 24h. Gene expression was assessed by RT-PCR and levels of IL6 and MCP1, as well as ACE2 activity, were assessed by ELISA. Expression of ICAM1 and PAI1 was assessed by immunoblotting. ACE2 activity was blocked by MLN4760 (ACE2 inhibitor) and siRNA. Viral infection was assessed by exposing Vero E6 (kidney epithelial cells; pos ctl) and EC to 10
5
pfu of SARS-CoV-2 where virus titre was measured by plaque assay. Co-IP coupled mass spectrometry protein identification and label free proteomics were used to investigate ACE2-mediated signalling. rS1p increased IL6 mRNA (14.2±2.1
vs.
C:0.61±0.03 2^-ddCT) and levels (1221.2±18.3
vs.
C:22.77±3.2 pg/mL); MCP1 mRNA (5.55±0.62
vs.
C:0.65±0.04 2^-ddCT) and levels (1110±13.33
vs.
C:876.9±33.4 pg/mL); ICAM1 (17.7±3.1
vs.
C:3.9±0.4 AU) and PAI1 (5.6±0.7
vs.
C: 2.9±0.2), p<0.05. MLN4760, but not rS1p, decreased ACE2 activity (367.4±18
vs.
C: 1011±268 RFU, p<0.05) and blocked rS1p effects on ICAM1 and PAI1. ACE2 siRNA blocked rS1p-induced IL6 release, ICAM1, and PAI1 responses as well as rS1p-induced NFκB activation. Proteomics analysis of the global effect of rS1, identified biological process enrichment of proteins from virus transcription and NFκB signalling. ACE2 Co-IP identified 216 interacting proteins (filtered with ≥1 unique peptide, 1% FDR), linked to cytokine production and inflammation. EC were not susceptible to SARS-CoV-2 infection, while the virus replicated well in Vero E6. In conclusion, we demonstrate that rS1p induces an inflammatory response through ACE2 in endothelial cells. These effects seem to be independent of viral infection. Our findings suggest that vascular inflammation in COVID-19 involves activation of ACE2-mediated pro-inflammatory signalling that may be unrelated to viral replication.
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Affiliation(s)
| | | | - Sheon Mary
- Univ of Glasgow, Glasgow, United Kingdom
| | | | | | | | | | - Imogen Herbert
- MRC - Univ of Glasgow Cntr for Virus Rsch, Glasgow, United Kingdom
| | - Vanessa Herder
- MRC - Univ of Glasgow Cntr for Virus Rsch, Glasgow, United Kingdom
| | | | - Steven McFarlane
- MRC - Univ of Glasgow Cntr for Virus Rsch, Glasgow, United Kingdom
| | | | - David Bhella
- MRC - Univ of Glasgow Cntr for Virus Rsch, Glasgow, United Kingdom
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11
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Morgan DC, Morris C, Mahindra A, Blair CM, Tejeda G, Herbert I, Turnbull ML, Lieber G, Willett BJ, Logan N, Smith B, Tobin AB, Bhella D, Baillie G, Jamieson AG. Stapled ACE2 peptidomimetics designed to target the SARS-CoV-2 spike protein do not prevent virus internalization. Pept Sci (Hoboken) 2021; 113:e24217. [PMID: 33615115 PMCID: PMC7883042 DOI: 10.1002/pep2.24217] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/24/2022]
Abstract
COVID-19 is caused by a novel coronavirus called severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Virus cell entry is mediated through a protein-protein interaction (PPI) between the SARS-CoV-2 spike protein and angiotensin-converting enzyme 2 (ACE2). A series of stapled peptide ACE2 peptidomimetics based on the ACE2 interaction motif were designed to bind the coronavirus S-protein RBD and inhibit binding to the human ACE2 receptor. The peptidomimetics were assessed for antiviral activity in an array of assays including a neutralization pseudovirus assay, immunofluorescence (IF) assay and in-vitro fluorescence polarization (FP) assay. However, none of the peptidomimetics showed activity in these assays, suggesting that an enhanced binding interface is required to outcompete ACE2 for S-protein RBD binding and prevent virus internalization.
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Affiliation(s)
| | | | | | | | - Gonzalo Tejeda
- Centre for Translational PharmacologyInstitute of Molecular Cell and Systems Biology, Davidson Building, University of GlasgowGlasgowUK
| | - Imogen Herbert
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | | | - Gauthier Lieber
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | | | - Nicola Logan
- MRC‐University of Glasgow Centre for Virus ResearchGlasgowUK
| | - Brian Smith
- Centre for Translational PharmacologyInstitute of Molecular Cell and Systems Biology, Davidson Building, University of GlasgowGlasgowUK
| | - Andrew B. Tobin
- Centre for Translational PharmacologyInstitute of Molecular Cell and Systems Biology, Davidson Building, University of GlasgowGlasgowUK
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12
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Vijayakrishnan S, McElwee M, Loney C, Rixon F, Bhella D. In situ structure of virus capsids within cell nuclei by correlative light and cryo-electron tomography. Sci Rep 2020; 10:17596. [PMID: 33077791 PMCID: PMC7572381 DOI: 10.1038/s41598-020-74104-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 09/24/2020] [Indexed: 12/02/2022] Open
Abstract
Cryo electron microscopy (cryo-EM), a key method for structure determination involves imaging purified material embedded in vitreous ice. Images are then computationally processed to obtain three-dimensional structures approaching atomic resolution. There is increasing interest in extending structural studies by cryo-EM into the cell, where biological structures and processes may be imaged in context. The limited penetrating power of electrons prevents imaging of thick specimens (> 500 nm) however. Cryo-sectioning methods employed to overcome this are technically challenging, subject to artefacts or involve specialised and costly equipment. Here we describe the first structure of herpesvirus capsids determined by sub-tomogram averaging from nuclei of eukaryotic cells, achieved by cryo-electron tomography (cryo-ET) of re-vitrified cell sections prepared using the Tokuyasu method. Our reconstructions confirm that the capsid associated tegument complex is present on capsids prior to nuclear egress. We demonstrate that this method is suited to both 3D structure determination and correlative light/electron microscopy, thus expanding the scope of cryogenic cellular imaging.
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Affiliation(s)
- Swetha Vijayakrishnan
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK.
| | - Marion McElwee
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK
| | - Colin Loney
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK
| | - Frazer Rixon
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK
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13
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Guzik TJ, Mohiddin SA, Dimarco A, Patel V, Savvatis K, Marelli-Berg FM, Madhur MS, Tomaszewski M, Maffia P, D’Acquisto F, Nicklin SA, Marian AJ, Nosalski R, Murray EC, Guzik B, Berry C, Touyz RM, Kreutz R, Wang DW, Bhella D, Sagliocco O, Crea F, Thomson EC, McInnes IB. COVID-19 and the cardiovascular system: implications for risk assessment, diagnosis, and treatment options. Cardiovasc Res 2020; 116:1666-1687. [PMID: 32352535 PMCID: PMC7197627 DOI: 10.1093/cvr/cvaa106] [Citation(s) in RCA: 870] [Impact Index Per Article: 217.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 04/11/2020] [Accepted: 04/14/2020] [Indexed: 02/06/2023] Open
Abstract
The novel coronavirus disease (COVID-19) outbreak, caused by SARS-CoV-2, represents the greatest medical challenge in decades. We provide a comprehensive review of the clinical course of COVID-19, its comorbidities, and mechanistic considerations for future therapies. While COVID-19 primarily affects the lungs, causing interstitial pneumonitis and severe acute respiratory distress syndrome (ARDS), it also affects multiple organs, particularly the cardiovascular system. Risk of severe infection and mortality increase with advancing age and male sex. Mortality is increased by comorbidities: cardiovascular disease, hypertension, diabetes, chronic pulmonary disease, and cancer. The most common complications include arrhythmia (atrial fibrillation, ventricular tachyarrhythmia, and ventricular fibrillation), cardiac injury [elevated highly sensitive troponin I (hs-cTnI) and creatine kinase (CK) levels], fulminant myocarditis, heart failure, pulmonary embolism, and disseminated intravascular coagulation (DIC). Mechanistically, SARS-CoV-2, following proteolytic cleavage of its S protein by a serine protease, binds to the transmembrane angiotensin-converting enzyme 2 (ACE2) -a homologue of ACE-to enter type 2 pneumocytes, macrophages, perivascular pericytes, and cardiomyocytes. This may lead to myocardial dysfunction and damage, endothelial dysfunction, microvascular dysfunction, plaque instability, and myocardial infarction (MI). While ACE2 is essential for viral invasion, there is no evidence that ACE inhibitors or angiotensin receptor blockers (ARBs) worsen prognosis. Hence, patients should not discontinue their use. Moreover, renin-angiotensin-aldosterone system (RAAS) inhibitors might be beneficial in COVID-19. Initial immune and inflammatory responses induce a severe cytokine storm [interleukin (IL)-6, IL-7, IL-22, IL-17, etc.] during the rapid progression phase of COVID-19. Early evaluation and continued monitoring of cardiac damage (cTnI and NT-proBNP) and coagulation (D-dimer) after hospitalization may identify patients with cardiac injury and predict COVID-19 complications. Preventive measures (social distancing and social isolation) also increase cardiovascular risk. Cardiovascular considerations of therapies currently used, including remdesivir, chloroquine, hydroxychloroquine, tocilizumab, ribavirin, interferons, and lopinavir/ritonavir, as well as experimental therapies, such as human recombinant ACE2 (rhACE2), are discussed.
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Affiliation(s)
- Tomasz J Guzik
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Internal Medicine, Jagiellonian University, Collegium Medicum, Kraków, Poland
| | - Saidi A Mohiddin
- Barts Heart Center, St Bartholomew’s NHS Trust, London, UK
- William Harvey Institute Queen Mary University of London, London, UK
| | | | - Vimal Patel
- Barts Heart Center, St Bartholomew’s NHS Trust, London, UK
| | | | | | - Meena S Madhur
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Maciej Tomaszewski
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, UK
| | - Pasquale Maffia
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Pharmacy, University of Naples Federico II, Naples, Italy
| | | | - Stuart A Nicklin
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Ali J Marian
- Department of Medicine, Center for Cardiovascular Genetics, Institute of Molecular Medicine, University of Texas Health Sciences Center at Houston, Houston, TX, USA
| | - Ryszard Nosalski
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Internal Medicine, Jagiellonian University, Collegium Medicum, Kraków, Poland
| | - Eleanor C Murray
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Bartlomiej Guzik
- Jagiellonian University Medical College, Institute of Cardiology, Department of Interventional Cardiology; John Paul II Hospital, Krakow, Poland
| | - Colin Berry
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Rhian M Touyz
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Reinhold Kreutz
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institut für Klinische Pharmakologie und Toxikologie, Germany
| | - Dao Wen Wang
- Division of Cardiology and Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, UK
| | - Orlando Sagliocco
- Emergency Department, Intensive Care Unit; ASST Bergamo Est Bolognini Hospital Bergamo, Italy
| | - Filippo Crea
- Department of Cardiovascular and Thoracic Sciences, Catholic University of the Sacred Heart, Largo A. Gemelli, 8, 00168 Rome, Italy
| | - Emma C Thomson
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, UK
- Department of Infectious Diseases, Queen Elizabeth University Hospital, Glasgow, UK
| | - Iain B McInnes
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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14
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Bhella D. Cryo-electron microscopy: an introduction to the technique, and considerations when working to establish a national facility. Biophys Rev 2019; 11:515-519. [PMID: 31359340 PMCID: PMC6682334 DOI: 10.1007/s12551-019-00571-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 06/24/2019] [Indexed: 11/24/2022] Open
Affiliation(s)
- David Bhella
- The Scottish Centre for Macromolecular Imaging, MRC - University of Glasgow Centre for Virus Research, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, UK.
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15
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Devant JM, Hofhaus G, Bhella D, Hansman GS. Heterologous expression of human norovirus GII.4 VP1 leads to assembly of T=4 virus-like particles. Antiviral Res 2019; 168:175-182. [PMID: 31145925 DOI: 10.1016/j.antiviral.2019.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 12/01/2022]
Abstract
Human noroviruses are a leading cause of acute gastroenteritis, yet there are still no vaccines or antivirals available. Expression of the norovirus capsid protein (VP1) in insect cells typically results in the formation of virus-like particles (VLPs) that are morphologically and antigenically comparable to native virions. Indeed, several different norovirus VLP candidates are currently used in clinical trials. So far, structural analysis of norovirus VLPs showed that the capsid has a T = 3 icosahedral symmetry and is composed of 180 copies of VP1 that are folded into three quasi-equivalent subunits (A, B, and C). In this study, the VLP structures of two norovirus GII.4 genetic variants that were identified in 1974 and 2012 were determined using cryo-EM. Surprisingly, we found that greater than 95% of these GII.4 VLPs were larger than virions and 3D reconstruction showed that these VLPs exhibited T = 4 icosahedral symmetry. We also discovered that the T = 4 VLPs presented several novel structural features. The T = 4 particles assembled from 240 copies of VP1 that adopted four quasi-equivalent conformations (A, B, C, and D) and formed two distinct dimers, A/B and C/D. The protruding domains were elevated ∼21 Å off the capsid shell, which was ∼7 Å more than in the previously studied GII.10 T = 3 VLPs. A small cavity and flap-like structure at the icosahedral two-fold axis disrupted the contiguous T = 4 shell. Overall, our findings indicated that GII.4 VP1 sequences assemble into T = 4 VLPs and these larger particles might have important consequences for VLP-based vaccine development.
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Affiliation(s)
- Jessica M Devant
- Schaller Research Group at the University of Heidelberg and the DKFZ, Heidelberg, Germany; Department of Infectious Diseases, Virology, University of Heidelberg, Heidelberg, Germany
| | - Götz Hofhaus
- Bioquant, CellNetWorks, University of Heidelberg, Heidelberg, Germany
| | - David Bhella
- MRC, University of Glasgow Centre for Virus Research, Glasgow, Scotland, UK
| | - Grant S Hansman
- Schaller Research Group at the University of Heidelberg and the DKFZ, Heidelberg, Germany; Department of Infectious Diseases, Virology, University of Heidelberg, Heidelberg, Germany.
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16
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Conley M, McElwee M, Goodfellow I, Bhella D. Assembly of a portal-like structure in feline calicivirus following receptor engagement. Access Microbiol 2019. [DOI: 10.1099/acmi.ac2019.po0105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Michaela Conley
- 1MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Marion McElwee
- 1MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | | | - David Bhella
- 1MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
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17
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Ho KL, Gabrielsen M, Beh PL, Kueh CL, Thong QX, Streetley J, Tan WS, Bhella D. Structure of the Macrobrachium rosenbergii nodavirus: A new genus within the Nodaviridae? PLoS Biol 2018; 16:e3000038. [PMID: 30346944 PMCID: PMC6211762 DOI: 10.1371/journal.pbio.3000038] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/01/2018] [Accepted: 10/05/2018] [Indexed: 11/19/2022] Open
Abstract
Macrobrachium rosenbergii nodavirus (MrNV) is a pathogen of freshwater prawns that poses a threat to food security and causes significant economic losses in the aquaculture industries of many developing nations. A detailed understanding of the MrNV virion structure will inform the development of strategies to control outbreaks. The MrNV capsid has also been engineered to display heterologous antigens, and thus knowledge of its atomic resolution structure will benefit efforts to develop tools based on this platform. Here, we present an atomic-resolution model of the MrNV capsid protein (CP), calculated by cryogenic electron microscopy (cryoEM) of MrNV virus-like particles (VLPs) produced in insect cells, and three-dimensional (3D) image reconstruction at 3.3 Å resolution. CryoEM of MrNV virions purified from infected freshwater prawn post-larvae yielded a 6.6 Å resolution structure, confirming the biological relevance of the VLP structure. Our data revealed that unlike other known nodavirus structures, which have been shown to assemble capsids having trimeric spikes, MrNV assembles a T = 3 capsid with dimeric spikes. We also found a number of surprising similarities between the MrNV capsid structure and that of the Tombusviridae: 1) an extensive network of N-terminal arms (NTAs) lines the capsid interior, forming long-range interactions to lace together asymmetric units; 2) the capsid shell is stabilised by 3 pairs of Ca2+ ions in each asymmetric unit; 3) the protruding spike domain exhibits a very similar fold to that seen in the spikes of the tombusviruses. These structural similarities raise questions concerning the taxonomic classification of MrNV.
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Affiliation(s)
- Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - Mads Gabrielsen
- CRUK Beatson Institute, Garscube Campus, Glasgow, Scotland United Kingdom
| | - Poay Ling Beh
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - Chare Li Kueh
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - Qiu Xian Thong
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
| | - James Streetley
- MRC-University of Glasgow Centre for Virus Research, Garscube Campus, Glasgow, Scotland, United Kingdom
| | - Wen Siang Tan
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia
- Institute of Bioscience, Universiti Putra Malaysia, UPM Serdang, Selangor Malaysia
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Garscube Campus, Glasgow, Scotland, United Kingdom
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18
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Abstract
Viroporins are short polypeptides encoded by viruses. These small membrane proteins assemble into oligomers that can permeabilize cellular lipid bilayers, disrupting the physiology of the host to the advantage of the virus. Consequently, efforts during the last few decades have been focused towards the discovery of viroporin channel inhibitors, but in general these have not been successful to produce licensed drugs. Viroporins are also involved in viral pathogenesis by engaging in critical interactions with viral proteins, or disrupting normal host cellular pathways through coordinated interactions with host proteins. These protein-protein interactions (PPIs) may become alternative attractive drug targets for the development of antivirals. In this sense, while thus far most antiviral molecules have targeted viral proteins, focus is moving towards targeting host proteins that are essential for virus replication. In principle, this largely would overcome the problem of resistance, with the possibility of using repositioned existing drugs. The precise role of these PPIs, their strain- and host- specificities, and the structural determination of the complexes involved, are areas that will keep the fields of virology and structural biology occupied for years to come. In the present review, we provide an update of the efforts in the characterization of the main PPIs for most viroporins, as well as the role of viroporins in these PPIs interactions.
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Affiliation(s)
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
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19
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McElwee M, Vijayakrishnan S, Rixon F, Bhella D. Structure of the herpes simplex virus portal-vertex. PLoS Biol 2018; 16:e2006191. [PMID: 29924793 PMCID: PMC6028144 DOI: 10.1371/journal.pbio.2006191] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 07/02/2018] [Accepted: 06/06/2018] [Indexed: 12/04/2022] Open
Abstract
Herpesviruses include many important human pathogens such as herpes simplex virus, cytomegalovirus, varicella-zoster virus, and the oncogenic Epstein-Barr virus and Kaposi sarcoma-associated herpesvirus. Herpes virions contain a large icosahedral capsid that has a portal at a unique 5-fold vertex, similar to that seen in the tailed bacteriophages. The portal is a molecular motor through which the viral genome enters the capsid during virion morphogenesis. The genome also exits the capsid through the portal-vertex when it is injected through the nuclear pore into the nucleus of a new host cell to initiate infection. Structural investigations of the herpesvirus portal-vertex have proven challenging, owing to the small size of the tail-like portal-vertex-associated tegument (PVAT) and the presence of the tegument layer that lays between the nucleocapsid and the viral envelope, obscuring the view of the portal-vertex. Here, we show the structure of the herpes simplex virus portal-vertex at subnanometer resolution, solved by electron cryomicroscopy (cryoEM) and single-particle 3D reconstruction. This led to a number of new discoveries, including the presence of two previously unknown portal-associated structures that occupy the sites normally taken by the penton and the Ta triplex. Our data revealed that the PVAT is composed of 10 copies of the C-terminal domain of pUL25, which are uniquely arranged as two tiers of star-shaped density. Our 3D reconstruction of the portal-vertex also shows that one end of the viral genome extends outside the portal in the manner described for some bacteriophages but not previously seen in any eukaryote viruses. Finally, we show that the viral genome is consistently packed in a highly ordered left-handed spool to form concentric shells of DNA. Our data provide new insights into the structure of a molecular machine critical to the biology of an important class of human pathogens.
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Affiliation(s)
- Marion McElwee
- Medical Research Council, University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Swetha Vijayakrishnan
- Medical Research Council, University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Frazer Rixon
- Medical Research Council, University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - David Bhella
- Medical Research Council, University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
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20
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Barski M, Brennan B, Miller OK, Potter JA, Vijayakrishnan S, Bhella D, Naismith JH, Elliott RM, Schwarz-Linek U. Rift Valley fever phlebovirus NSs protein core domain structure suggests molecular basis for nuclear filaments. eLife 2017; 6. [PMID: 28915104 PMCID: PMC5601994 DOI: 10.7554/elife.29236] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/21/2017] [Indexed: 12/24/2022] Open
Abstract
Rift Valley fever phlebovirus (RVFV) is a clinically and economically important pathogen increasingly likely to cause widespread epidemics. RVFV virulence depends on the interferon antagonist non-structural protein (NSs), which remains poorly characterized. We identified a stable core domain of RVFV NSs (residues 83–248), and solved its crystal structure, a novel all-helical fold organized into highly ordered fibrils. A hallmark of RVFV pathology is NSs filament formation in infected cell nuclei. Recombinant virus encoding the NSs core domain induced intranuclear filaments, suggesting it contains all essential determinants for nuclear translocation and filament formation. Mutations of key crystal fibril interface residues in viruses encoding full-length NSs completely abrogated intranuclear filament formation in infected cells. We propose the fibrillar arrangement of the NSs core domain in crystals reveals the molecular basis of assembly of this key virulence factor in cell nuclei. Our findings have important implications for fundamental understanding of RVFV virulence. Rift Valley fever phlebovirus (RVFV) is a virus of humans and livestock, transmitted by mosquitos and contact with infected animals. Infection can cause severe disease, including hemorrhagic fever, and may lead to death. Historically, the virus was only found in central Africa but it has spread for instance to the Arabian Peninsula. There is a risk that the virus may appear in temperate regions including Europe because global warming is allowing the mosquitos that carry the virus to extend their geographic range. There are no vaccines or treatments available for use in humans so if there is a serious outbreak of the virus it could become an epidemic and cause great economic losses and severe human disease. RVFV relies on a protein called NSs to cause disease. In cells of infected animals and humans NSs forms filaments inside the nucleus, the control center of the cell, and disarms the immune system. However, it is not known precisely how NSs works. To address this question, Barski, Brennan et al. used a technique called X-ray crystallography to study the atomic three-dimensional structure of NSs. This revealed that the center of the protein contains a core domain that causes the filaments to form. Further experiments identified how the NSs core comes together to build the filaments inside the cell nucleus. These findings represent an important step towards understanding how the NSs protein helps RVFV to cause disease in humans and livestock. In the future, this work may aid the development of much needed drugs and vaccines against RVFV.
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Affiliation(s)
- Michal Barski
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
| | - Benjamin Brennan
- MRC-University of Glasgow Centre for Virus Research, London, United Kingdom
| | - Ona K Miller
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
| | - Jane A Potter
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
| | | | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, London, United Kingdom
| | - James H Naismith
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
| | - Richard M Elliott
- MRC-University of Glasgow Centre for Virus Research, London, United Kingdom
| | - Ulrich Schwarz-Linek
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
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21
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Ho KL, Kueh CL, Beh PL, Tan WS, Bhella D. Cryo-Electron Microscopy Structure of the Macrobrachium rosenbergii Nodavirus Capsid at 7 Angstroms Resolution. Sci Rep 2017; 7:2083. [PMID: 28522842 PMCID: PMC5437026 DOI: 10.1038/s41598-017-02292-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 04/18/2017] [Indexed: 11/10/2022] Open
Abstract
White tail disease in the giant freshwater prawn Macrobrachium rosenbergii causes significant economic losses in shrimp farms and hatcheries and poses a threat to food-security in many developing countries. Outbreaks of Macrobrachium rosenbergii nodavirus (MrNV), the causative agent of white tail disease (WTD) are associated with up to 100% mortality rates. There are no interventions available to treat or prevent MrNV disease however. Here we show the structure of MrNV virus-like particles (VLPs) produced by recombinant expression of the capsid protein, using cryogenic electron microscopy. Our data show that MrNV VLPs package nucleic acids in a manner reminiscent of other known nodavirus structures. The structure of the capsid however shows striking differences from insect and fish infecting nodaviruses, which have been shown to assemble trimer-clustered T = 3 icosahedral virus particles. MrNV particles have pronounced dimeric blade-shaped spikes extending up to 6 nm from the outer surface of the capsid shell. Our structural analysis supports the assertion that MrNV may belong to a new genus of the Nodaviridae. Moreover, our study provides the first structural view of an important pathogen affecting aquaculture industries across the world.
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Affiliation(s)
- Kok Lian Ho
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Chare Li Kueh
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, 43400 UPM, Serdang, Selangor, Malaysia
| | - Poay Ling Beh
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Serdang, Selangor, Malaysia
| | - Wen Siang Tan
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, 43400 UPM, Serdang, Selangor, Malaysia
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow, G61 1QH, Scotland, UK.
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22
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Conley M, Emmott E, Orton R, Taylor D, Carneiro DG, Murata K, Goodfellow IG, Hansman GS, Bhella D. Vesivirus 2117 capsids more closely resemble sapovirus and lagovirus particles than other known vesivirus structures. J Gen Virol 2017; 98:68-76. [PMID: 27902397 PMCID: PMC5370393 DOI: 10.1099/jgv.0.000658] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 11/11/2016] [Indexed: 01/06/2023] Open
Abstract
Vesivirus 2117 is an adventitious agent that, in 2009, was identified as a contaminant of Chinese hamster ovary cells propagated in bioreactors at a pharmaceutical manufacturing plant belonging to Genzyme. The consequent interruption in supply of Fabrazyme and Cerezyme (drugs used to treat Fabry and Gaucher diseases, respectively) caused significant economic losses. Vesivirus 2117 is a member of the Caliciviridae, a family of small icosahedral viruses encoding a positive-sense RNA genome. We have used cryo-electron microscopy and three-dimensional image reconstruction to calculate a structure of vesivirus 2117 virus-like particles as well as feline calicivirus and a chimeric sapovirus. We present a structural comparison of several members of the Caliciviridae, showing that the distal P domain of vesivirus 2117 is morphologically distinct from that seen in other known vesivirus structures. Furthermore, at intermediate resolutions, we found a high level of structural similarity between vesivirus 2117 and Caliciviridae from other genera: sapovirus and rabbit hemorrhagic disease virus. Phylogenetic analysis confirms vesivirus 2117 as a vesivirus closely related to canine vesiviruses. We postulate that morphological differences in virion structure seen between vesivirus clades may reflect differences in receptor usage.
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Affiliation(s)
- Michaela Conley
- Medical Research Council – University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - Edward Emmott
- Department of Pathology, Division of Virology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Richard Orton
- Medical Research Council – University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
| | - David Taylor
- National Institute for Physiological Sciences (NIPS), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Present address: Howard Hughes Medical Institute, 742 Stanley Hall, MS 3220 University of California, Berkeley, CA 94720-3220, USA
| | - Daniel G Carneiro
- Medical Research Council – University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
- Present address: School of Immunity and Infection, Institute of Biomedical Research, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences (NIPS), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Ian G Goodfellow
- Department of Pathology, Division of Virology, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
| | - Grant S Hansman
- National Institute for Physiological Sciences (NIPS), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
- Present address: Centre for Infectious Diseases, Department of Virology, University Hospital Heidelberg, Im Neuenheimer Feld 324, Heidelberg 69120, Germany
| | - David Bhella
- Medical Research Council – University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
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23
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Abstract
Clinical isolates of influenza virus produce pleomorphic virus particles, including extremely long filamentous virions. In contrast, strains of influenza that have adapted to laboratory growth typically produce only spherical virions. As a result, the filamentous phenotype has been overlooked in most influenza virus research. Recent advances in imaging and improved animal models have highlighted the distinct structure and functional relevance of filamentous virions. In this review we summarize what is currently known about these strikingly elongated virus particles and discuss their possible roles in clinical infections.
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Affiliation(s)
- Bernadeta Dadonaite
- Sir William Dunn School of Pathology, University of Oxford, South Parks Rd, Oxford OX1 3RE, UK
| | - Swetha Vijayakrishnan
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow, Lanarkshire G61 1QH, UK
| | - Ervin Fodor
- Sir William Dunn School of Pathology, University of Oxford, South Parks Rd, Oxford OX1 3RE, UK
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow, Lanarkshire G61 1QH, UK
| | - Edward C Hutchinson
- MRC-University of Glasgow Centre for Virus Research, University of Glasgow, 464 Bearsden Rd, Bearsden, Glasgow, Lanarkshire G61 1QH, UK.,Sir William Dunn School of Pathology, University of Oxford, South Parks Rd, Oxford OX1 3RE, UK
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24
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Abstract
As obligate intracellular parasites, viruses must traverse the host-cell plasma membrane to initiate infection. This presents a formidable barrier, which they have evolved diverse strategies to overcome. Common to all entry pathways, however, is a mechanism of specific attachment to cell-surface macromolecules or ‘receptors’. Receptor usage frequently defines viral tropism, and consequently, the evolutionary changes in receptor specificity can lead to emergence of new strains exhibiting altered pathogenicity or host range. Several classes of molecules are exploited as receptors by diverse groups of viruses, including, for example, sialic acid moieties and integrins. In particular, many cell-adhesion molecules that belong to the immunoglobulin-like superfamily of proteins (IgSF CAMs) have been identified as viral receptors. Structural analysis of the interactions between viruses and IgSF CAM receptors has not shown binding to specific features, implying that the Ig-like fold may not be key. Both proteinaceous and enveloped viruses exploit these proteins, however, suggesting convergent evolution of this trait. Their use is surprising given the usually occluded position of CAMs on the cell surface, such as at tight junctions. Nonetheless, the reason for their widespread involvement in virus entry most probably originates in their functional rather than structural characteristics.
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Affiliation(s)
- David Bhella
- Medical Research Council-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, UK
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McGonigle R, Yap WB, Ong ST, Gatherer D, Bakker SE, Tan WS, Bhella D. An N-terminal extension to the hepatitis B virus core protein forms a poorly ordered trimeric spike in assembled virus-like particles. J Struct Biol 2014; 189:73-80. [PMID: 25557498 PMCID: PMC4318616 DOI: 10.1016/j.jsb.2014.12.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 11/24/2014] [Accepted: 12/24/2014] [Indexed: 01/24/2023]
Abstract
Virus-like particles composed of the core antigen of hepatitis B virus (HBcAg) have been shown to be an effective platform for the display of foreign epitopes in vaccine development. Heterologous sequences have been successfully inserted at both amino and carboxy termini as well as internally at the major immunodominant epitope. We used cryogenic electron microscopy (CryoEM) and three-dimensional image reconstruction to investigate the structure of VLPs assembled from an N-terminal extended HBcAg that contained a polyhistidine tag. The insert was seen to form a trimeric spike on the capsid surface that was poorly resolved, most likely owing to it being flexible. We hypothesise that the capacity of N-terminal inserts to form trimers may have application in the development of multivalent vaccines to trimeric antigens. Our analysis also highlights the value of tools for local resolution assessment in studies of partially disordered macromolecular assemblies by cryoEM.
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Affiliation(s)
- Richard McGonigle
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK
| | - Wei Boon Yap
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Swee Tin Ong
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Derek Gatherer
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK
| | - Saskia E Bakker
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK
| | - Wen Siang Tan
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Sir Michael Stoker Building, Garscube Campus, 464 Bearsden Road, Glasgow G61 1QH, Scotland, UK.
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Hacker C, Howell M, Bhella D, Lucocq J. Strategies for maximizing ATP supply in the microsporidian Encephalitozoon cuniculi: direct binding of mitochondria to the parasitophorous vacuole and clustering of the mitochondrial porin VDAC. Cell Microbiol 2013; 16:565-79. [PMID: 24245785 PMCID: PMC4233961 DOI: 10.1111/cmi.12240] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 10/11/2013] [Accepted: 11/11/2013] [Indexed: 11/29/2022]
Abstract
Microsporidia are obligate intracellular parasites with extremely reduced genomes and a dependence on host-derived ATP. The microsporidium Encephalitozoon cuniculi proliferates within a membranous vacuole and we investigated how the ATP supply is optimized at the vacuole-host interface. Using spatial EM quantification (stereology), we found a single layer of mitochondria coating substantial proportions of the parasitophorous vacuole. Mitochondrial binding occurred preferentially over the vegetative 'meront' stages of the parasite, which bulged into the cytoplasm, thereby increasing the membrane surface available for mitochondrial interaction. In a broken cell system mitochondrial binding was maintained and was typified by electron dense structures (< 10 nm long) bridging between outer mitochondrial and vacuole membranes. In broken cells mitochondrial binding was sensitive to a range of protease treatments. The function of directly bound mitochondria, as measured by the membrane potential sensitive dye JC-1, was indistinguishable from other mitochondria in the cell although there was a generalized depression of the membrane potential in infected cells. Finally, quantitative immuno-EM revealed that the ATP-delivering mitochondrial porin, VDAC, was concentrated atthe mitochondria-vacuole interaction site. Thus E. cuniculi appears to maximize ATP supply by direct binding of mitochondria to the parasitophorous vacuole bringing this organelle within 0.020 microns of the growing vegetative form of the parasite. ATP-delivery is further enhanced by clustering of ATP transporting porins in those regions of the outer mitochondrial membrane lying closest to the parasite.
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Affiliation(s)
- Christian Hacker
- School of Medicine, University of St Andrews, North Haugh, St Andrews, Fife, KF16 9TF, UK
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Vijayakrishnan S, Loney C, Jackson D, Suphamungmee W, Rixon FJ, Bhella D. Cryotomography of budding influenza A virus reveals filaments with diverse morphologies that mostly do not bear a genome at their distal end. PLoS Pathog 2013; 9:e1003413. [PMID: 23754946 PMCID: PMC3675018 DOI: 10.1371/journal.ppat.1003413] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 04/27/2013] [Indexed: 11/22/2022] Open
Abstract
Influenza viruses exhibit striking variations in particle morphology between strains. Clinical isolates of influenza A virus have been shown to produce long filamentous particles while laboratory-adapted strains are predominantly spherical. However, the role of the filamentous phenotype in the influenza virus infectious cycle remains undetermined. We used cryo-electron tomography to conduct the first three-dimensional study of filamentous virus ultrastructure in particles budding from infected cells. Filaments were often longer than 10 microns and sometimes had bulbous heads at their leading ends, some of which contained tubules we attribute to M1 while none had recognisable ribonucleoprotein (RNP) and hence genome segments. Long filaments that did not have bulbs were infrequently seen to bear an ordered complement of RNPs at their distal ends. Imaging of purified virus also revealed diverse filament morphologies; short rods (bacilliform virions) and longer filaments. Bacilliform virions contained an ordered complement of RNPs while longer filamentous particles were narrower and mostly appeared to lack this feature, but often contained fibrillar material along their entire length. The important ultrastructural differences between these diverse classes of particles raise the possibility of distinct morphogenetic pathways and functions during the infectious process. Influenza viruses that have been cultivated in the laboratory usually produce particles that are spherical. However, viruses isolated from patients frequently produce long filamentous particles, as well as smaller elliptical particles that we term “bacilliform virions”. Long filaments may be important for cell-to-cell transmission or facilitate release of the smaller particles by disrupting the mucous layer of the respiratory tract. We have used three-dimensional electron microscopy to investigate the structure of influenza virus filaments ‘budding’ from cells. We found that many of the long filaments had a large bulbous head at the end furthest from the cell. Many of these bulbs were empty while some contained tubules that we believe are made of a scaffold-protein M1 that usually lines the inner surface of the viral membrane. Bacilliform virions contain genomes comprised of eight segments of RNA; these are each wrapped up in protein and packaged in an ordered manner. None of the bulb-headed filaments and very few narrower ones had this feature. We hypothesise that the diverse viral structures we have seen suggest distinct assembly pathways and moreover functions. Long filamentous structures that do not appear to contain genomes may combat the immune response or help the smaller virus particles spread.
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Affiliation(s)
| | - Colin Loney
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - David Jackson
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, Fife, United Kingdom
| | | | - Frazer J. Rixon
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
| | - David Bhella
- MRC Centre for Virus Research, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
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Bakker SE, Duquerroy S, Galloux M, Loney C, Conner E, Eléouët JF, Rey FA, Bhella D. The respiratory syncytial virus nucleoprotein-RNA complex forms a left-handed helical nucleocapsid. J Gen Virol 2013; 94:1734-1738. [PMID: 23677789 PMCID: PMC3749527 DOI: 10.1099/vir.0.053025-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Respiratory syncytial virus (RSV) is an important human pathogen. Its nucleocapsid (NC), which comprises the negative sense RNA viral genome coated by the viral nucleoprotein N, is a critical assembly that serves as template for both mRNA synthesis and genome replication. We have previously described the X-ray structure of an NC-like structure: a decameric ring formed of N-RNA that mimics one turn of the helical NC. In the absence of experimental data we had hypothesized that the NC helix would be right-handed, as the N–N contacts in the ring appeared to more easily adapt to that conformation. We now unambiguously show that the RSV NC is a left-handed helix. We further show that the contacts in the ring can be distorted to maintain key N–N-protein interactions in a left-handed helix, and discuss the implications of the resulting atomic model of the helical NC for viral replication and transcription.
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Affiliation(s)
- Saskia E Bakker
- Medical Research Council - University of Glasgow Centre for Virus Research, Church Street, Glasgow, G11 5JR, UK
| | - Stéphane Duquerroy
- Université Paris Sud, 91405 Orsay, France.,Institut Pasteur, Unité de Virologie Structurale, Département de Virologie and CNRS Unité de Recherche Associée (URA) 3015, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Marie Galloux
- INRA, Unité de Virologie et Immunologie Moléculaires, Domaine du Vilvert, 78350 Jouy-en-Josas, France
| | - Colin Loney
- Medical Research Council - University of Glasgow Centre for Virus Research, Church Street, Glasgow, G11 5JR, UK
| | - Edward Conner
- Medical Research Council - University of Glasgow Centre for Virus Research, Church Street, Glasgow, G11 5JR, UK
| | - Jean-François Eléouët
- INRA, Unité de Virologie et Immunologie Moléculaires, Domaine du Vilvert, 78350 Jouy-en-Josas, France
| | - Félix A Rey
- Institut Pasteur, Unité de Virologie Structurale, Département de Virologie and CNRS Unité de Recherche Associée (URA) 3015, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
| | - David Bhella
- Medical Research Council - University of Glasgow Centre for Virus Research, Church Street, Glasgow, G11 5JR, UK
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30
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Schmid MF, Hecksel CW, Rochat RH, Bhella D, Chiu W, Rixon FJ. A tail-like assembly at the portal vertex in intact herpes simplex type-1 virions. PLoS Pathog 2012; 8:e1002961. [PMID: 23055933 PMCID: PMC3464221 DOI: 10.1371/journal.ppat.1002961] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
Abstract
Herpes viruses are prevalent and well characterized human pathogens. Despite extensive study, much remains to be learned about the structure of the genome packaging and release machinery in the capsids of these large and complex double-stranded DNA viruses. However, such machinery is well characterized in tailed bacteriophage, which share a common evolutionary origin with herpesvirus. In tailed bacteriophage, the genome exits from the virus particle through a portal and is transferred into the host cell by a complex apparatus (i.e. the tail) located at the portal vertex. Here we use electron cryo-tomography of human herpes simplex type-1 (HSV-1) virions to reveal a previously unsuspected feature at the portal vertex, which extends across the HSV-1 tegument layer to form a connection between the capsid and the viral membrane. The location of this assembly suggests that it plays a role in genome release into the nucleus and is also important for virion architecture.
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Affiliation(s)
- Michael F. Schmid
- National Center for Macromolecular Imaging, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Corey W. Hecksel
- National Center for Macromolecular Imaging, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Ryan H. Rochat
- National Center for Macromolecular Imaging, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
| | - David Bhella
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Wah Chiu
- National Center for Macromolecular Imaging, Verna and Marrs Mclean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas, United States of America
- Graduate Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
| | - Frazer J. Rixon
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
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Byron O, Lindsay G, Vijayakrishnan S, Kelly S, Bhella D, McGow D, Nutley M, Cooper A, Kropholler P, Callow P, Forsyth T, Gilbert R, Gilbert D. Neutron scattering reveals human pyruvate dehydrogenase complex organisation. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311095511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Vijayakrishnan S, Kelly S, Gilbert R, Callow P, Bhella D, Forsyth T, Lindsay J, Byron O. Solution structure and characterisation of the human pyruvate dehydrogenase complex core assembly. J Mol Biol 2010; 399:71-93. [PMID: 20361979 PMCID: PMC2880790 DOI: 10.1016/j.jmb.2010.03.043] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Revised: 03/19/2010] [Accepted: 03/23/2010] [Indexed: 12/02/2022]
Abstract
Mammalian pyruvate dehydrogenase complex (PDC) is a key multi-enzyme assembly that is responsible for glucose homeostasis maintenance and conversion of pyruvate into acetyl-CoA. It comprises a central pentagonal dodecahedral core consisting of two subunit types (E2 and E3BP) to which peripheral enzymes (E1 and E3) bind tightly but non-covalently. Currently, there are two conflicting models of PDC (E2+E3BP) core organisation: the 'addition' model (60+12) and the 'substitution' model (48+12). Here we present the first ever low-resolution structures of human recombinant full-length PDC core (rE2/E3BP), truncated PDC core (tE2/E3BP) and native bovine heart PDC core (bE2/E3BP) obtained by small-angle X-ray scattering and small-angle neutron scattering. These structures, corroborated by negative-stain and cryo electron microscopy data, clearly reveal open pentagonal core faces, favouring the 'substitution' model of core organisation. The native and recombinant core structures are all similar to the truncated bacterial E2 core crystal structure obtained previously. Cryo-electron microscopy reconstructions of rE2/E3BP and rE2/E3BP:E3 directly confirm that the core has open pentagonal faces, agree with scattering-derived models and show density extending outwards from their surfaces, which is much more structurally ordered in the presence of E3. Additionally, analytical ultracentrifugation characterisation of rE2/E3BP, rE2 (full-length recombinant E2-only) and tE2/E3BP supports the substitution model. Superimposition of the small-angle neutron scattering tE2/E3BP and truncated bacterial E2 crystal structures demonstrates conservation of the overall pentagonal dodecahedral morphology, despite evolutionary diversity. In addition, unfolding studies using circular dichroism and tryptophan fluorescence spectroscopy show that the rE2/E3BP is less stable than its rE2 counterpart, indicative of a role for E3BP in core destabilisation. The architectural complexity and lower stability of the E2/E3BP core may be of benefit to mammals, where sophisticated fine-tuning is required for cores with optimal catalytic and regulatory efficiencies.
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Key Words
- pdc, pyruvate dehydrogenase complex
- ogdc, 2-oxoglutarate dehydrogenase complex
- ld, lipoyl domain
- sbd, subunit binding domain
- ctd, c-terminal domain
- pdb, protein data bank
- em, electron microscopy
- auc, analytical ultracentrifugation
- saxs, small-angle x-ray scattering
- sans, small-angle neutron scattering
- sv, sedimentation velocity
- se, sedimentation equilibrium
- gfc, gel-filtration chromatography
- hbm, hydrodynamic bead model
- sas, small-angle scattering
- ctf, contrast transfer function
- edta, ethylenediaminetetraacetic acid
- embl, european molecular biology laboratory
- ill, institut laue langevin
- pyruvate dehydrogenase complex
- sas
- auc
- cryo-em
- gdmcl unfolding
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Affiliation(s)
- S. Vijayakrishnan
- Division of Molecular and Cell Biology, Faculty of Biomedical and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, UK
- Division of Infection and Immunity, Faculty of Biomedical and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8TA, UK
| | - S.M. Kelly
- Division of Molecular and Cell Biology, Faculty of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - R.J.C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - P. Callow
- EPSAM and ISTM Research Institutes, Keele University, Staffordshire ST5 5BG, UK
- Partnership for Structural Biology, Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble, France
| | - D. Bhella
- Institute of Virology, University of Glasgow, Church Street, Glasgow G11 5JR, UK
| | - T. Forsyth
- EPSAM and ISTM Research Institutes, Keele University, Staffordshire ST5 5BG, UK
- Partnership for Structural Biology, Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble, France
| | - J.G. Lindsay
- Division of Molecular and Cell Biology, Faculty of Biomedical and Life Sciences, Davidson Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - O. Byron
- Division of Infection and Immunity, Faculty of Biomedical and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8TA, UK
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Parsons JB, Frank S, Bhella D, Liang M, Prentice MB, Mulvihill DP, Warren MJ. Synthesis of Empty Bacterial Microcompartments, Directed Organelle Protein Incorporation, and Evidence of Filament-Associated Organelle Movement. Mol Cell 2010; 38:305-15. [DOI: 10.1016/j.molcel.2010.04.008] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 01/25/2010] [Accepted: 04/02/2010] [Indexed: 11/26/2022]
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Schmid MF, Chiu W, Bhella D, Rixon F. A Uniique Density at the Portal Vertex of HSV Virions Revealed by Asymmetric Averaging of Subtomograms. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.2063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Tawar RG, Duquerroy S, Vonrhein C, Varela PF, Damier-Piolle L, Castagné N, MacLellan K, Bedouelle H, Bricogne G, Bhella D, Eléouët JF, Rey FA. Crystal structure of a nucleocapsid-like nucleoprotein-RNA complex of respiratory syncytial virus. Science 2009; 326:1279-83. [PMID: 19965480 DOI: 10.1126/science.1177634] [Citation(s) in RCA: 248] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The respiratory syncytial virus (RSV) is an important human pathogen, yet neither a vaccine nor effective therapies are available to treat infection. To help elucidate the replication mechanism of this RNA virus, we determined the three-dimensional (3D) crystal structure at 3.3 A resolution of a decameric, annular ribonucleoprotein complex of the RSV nucleoprotein (N) bound to RNA. This complex mimics one turn of the viral helical nucleocapsid complex, which serves as template for viral RNA synthesis. The RNA wraps around the protein ring, with seven nucleotides contacting each N subunit, alternating rows of four and three stacked bases that are exposed and buried within a protein groove, respectively. Combined with electron microscopy data, this structure provides a detailed model for the RSV nucleocapsid, in which the bases are accessible for readout by the viral polymerase. Furthermore, the nucleoprotein structure highlights possible key sites for drug targeting.
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Affiliation(s)
- Rajiv G Tawar
- Institut Pasteur, Unité de Virologie Structurale, Département de Virologie and CNRS Unité de Recherche Associée (URA) 3015, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
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36
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Greig JA, Buckley SM, Waddington SN, Parker AL, Bhella D, Pink R, Rahim AA, Morita T, Nicklin SA, McVey JH, Baker AH. Influence of coagulation factor x on in vitro and in vivo gene delivery by adenovirus (Ad) 5, Ad35, and chimeric Ad5/Ad35 vectors. Mol Ther 2009; 17:1683-91. [PMID: 19603000 DOI: 10.1038/mt.2009.152] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The binding of coagulation factor X (FX) to the hexon of adenovirus (Ad) 5 is pivotal for hepatocyte transduction. However, vectors based on Ad35, a subspecies B Ad, are in development for cancer gene therapy, as Ad35 utilizes CD46 (which is upregulated in many cancers) for transduction. We investigated whether interaction of Ad35 with FX influenced vector tropism using Ad5, Ad35, and Ad5/Ad35 chimeras: Ad5/fiber(f)35, Ad5/penton(p)35/f35, and Ad35/f5. Surface plasmon resonance (SPR) revealed that Ad35 and Ad35/f5 bound FX with approximately tenfold lower affinities than Ad5 hexon-containing viruses, and electron cryomicroscopy (cryo-EM) demonstrated a direct Ad35 hexon:FX interaction. The presence of physiological levels of FX significantly inhibited transduction of vectors containing Ad35 fibers (Ad5/f35, Ad5/p35/f35, and Ad35) in CD46-positive cells. Vectors were intravenously administered to CD46 transgenic mice in the presence and absence of FX-binding protein (X-bp), resulting in reduced liver accumulation for all vectors. Moreover, Ad5/f35 and Ad5/p35/f35 efficiently accumulated in the lung, whereas Ad5 demonstrated poor lung targeting. Additionally, X-bp significantly reduced lung genome accumulation for Ad5/f35 and Ad5/p35/f35, whereas Ad35 was significantly enhanced. In summary, vectors based on the full Ad35 serotype will be useful vectors for selective gene transfer via CD46 due to a weaker FX interaction compared to Ad5.
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Affiliation(s)
- Jenny A Greig
- British Heart Foundation Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow G12 8TA, UK
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37
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Waddington SN, McVey JH, Bhella D, Parker AL, Barker K, Atoda H, Pink R, Buckley SMK, Greig JA, Denby L, Custers J, Morita T, Francischetti IMB, Monteiro RQ, Barouch DH, van Rooijen N, Napoli C, Havenga MJE, Nicklin SA, Baker AH. Adenovirus serotype 5 hexon mediates liver gene transfer. Cell 2008; 132:397-409. [PMID: 18267072 DOI: 10.1016/j.cell.2008.01.016] [Citation(s) in RCA: 479] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 12/10/2007] [Accepted: 01/15/2008] [Indexed: 11/26/2022]
Abstract
Adenoviruses are used extensively as gene transfer agents, both experimentally and clinically. However, targeting of liver cells by adenoviruses compromises their potential efficacy. In cell culture, the adenovirus serotype 5 fiber protein engages the coxsackievirus and adenovirus receptor (CAR) to bind cells. Paradoxically, following intravascular delivery, CAR is not used for liver transduction, implicating alternate pathways. Recently, we demonstrated that coagulation factor (F)X directly binds adenovirus leading to liver infection. Here, we show that FX binds to the Ad5 hexon, not fiber, via an interaction between the FX Gla domain and hypervariable regions of the hexon surface. Binding occurs in multiple human adenovirus serotypes. Liver infection by the FX-Ad5 complex is mediated through a heparin-binding exosite in the FX serine protease domain. This study reveals an unanticipated function for hexon in mediating liver gene transfer in vivo.
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Affiliation(s)
- Simon N Waddington
- Department of Haematology, Haemophilia Centre and Haemostasis Unit, Royal Free and University College Medical School, London NW3 2PF, UK
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38
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Cao Z, Bhella D, Lindsay JG. Reconstitution of the mitochondrial PrxIII antioxidant defence pathway: general properties and factors affecting PrxIII activity and oligomeric state. J Mol Biol 2007; 372:1022-1033. [PMID: 17707404 DOI: 10.1016/j.jmb.2007.07.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 07/04/2007] [Accepted: 07/10/2007] [Indexed: 10/23/2022]
Abstract
The mitochondrial 2-Cys peroxiredoxin PrxIII serves as a thioredoxin-dependent peroxidase operating in tandem with its cognate partners, an organelle-specific thioredoxin (Trx2) and NADP-linked thioredoxin reductase (TRR2). This PrxIII pathway is emerging as a primary regulator of intracellular H(2)O(2) levels with dual roles in antioxidant defence and H(2)O(2)-mediated signalling. Here we describe the reconstitution of the mammalian PrxIII pathway in vitro from its purified recombinant components and investigate some of its overall properties. Employing the site-directed PrxIII mutants C47S, C66S and C168S, the putative N and C-terminal catalytic cysteine residues are shown to be essential for function whereas the C66S mutant retains full activity. The pathway attains maximal capacity at low H(2)O(2) concentrations (<10 microM) and is progressively inhibited in the range 0.1 mM to 1.0 mM peroxide. Damage to PrxIII caused by over-oxidation is confirmed by the appearance of abnormal oxidised species of PrxIII on SDS-PAGE at elevated H(2)O(2) levels. The presence of an N-terminal His-tag on PrxIII markedly enhances dodecamer stability, particularly apparent in its oxidised state. Its removal promotes oxidised PrxIII dissociation into dimers and leads to a 3.0-3.5-fold stimulation in peroxidase activity. The unusual concatenated crystal structure of PrxIII consisting of two-interlocked dodecameric rings is also evident in dilute solution employing transmission electron microscopy; however, it represents only 3-5% of the population with most molecules present as single toroids. Moreover, concatenated PrxIII C168S reverts to single toroids on crystal dissolution indicating that these higher-order structures are produced dynamically during the crystallisation process.
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Affiliation(s)
- Zhenbo Cao
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
| | - David Bhella
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, Scotland, UK
| | - J Gordon Lindsay
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
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39
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Abstract
Respiratory syncytial virus (RSV), a nonsegmented, negative-sense RNA-containing virus, is a common cause of lower respiratory tract disease. Expression of RSV nucleocapsid protein (N) in insect cells using the baculovirus expression system leads to the formation of N-RNA complexes that are morphologically indistinguishable from viral nucleocapsids. When imaged in an electron microscope, three distinct types of structures were observed: tightly wound short-pitch helices, highly extended helices, and rings. Negative stain images of N-RNA rings were used to calculate a three-dimensional reconstruction at 24 A resolution, revealing features similar to those observed in nucleocapsids from other viruses of the order Mononegavirales. The reconstructed N-RNA rings comprise 10 N monomers and have an external radius of 83 A and an internal radius of 40 A. Comparison of this structure with crystallographic data from rabies virus and vesicular stomatitis virus N-RNA rings reveals striking morphological similarities.
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Affiliation(s)
- Kirsty Maclellan
- Medical Research Council Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, United Kingdom
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40
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Tran TL, Castagné N, Bhella D, Varela PF, Bernard J, Chilmonczyk S, Berkenkamp S, Benhamo V, Grznarova K, Grosclaude J, Nespoulos C, Rey FA, Eléouët JF. The nine C-terminal amino acids of the respiratory syncytial virus protein P are necessary and sufficient for binding to ribonucleoprotein complexes in which six ribonucleotides are contacted per N protein protomer. J Gen Virol 2007; 88:196-206. [PMID: 17170452 DOI: 10.1099/vir.0.82282-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The respiratory syncytial virus (RSV) phosphoprotein (P) is a major polymerase co-factor that interacts with both the large polymerase fragment (L) and the nucleoprotein (N). The N-binding domain of RSV P has been investigated by co-expression of RSV P and N proteins in Escherichia coli. Pull-down assays performed with a series of truncated forms of P fused to glutathione S-transferase (GST) revealed that the region comprising the last nine C-terminal amino acid residues of P (233-DNDLSLEDF-241) is sufficient for efficient binding to N. Site-directed mutagenesis shows that the last four residues of this peptide are crucial for binding and must be present at the end of a flexible C-terminal tail. The presence of the P oligomerization domain (residues 100-160) was an important stabilizing factor for the interaction. The tetrameric full-length P fused to GST was able to pull down both helical and ring structures, whereas a monomeric C-terminal fragment of P (residues 161-241) fused to GST pulled down exclusively RNA-N rings. Electron-microscopy analysis of the purified rings showed the presence of two types of complex: undecamers (11N) and decamers (10N). Mass-spectrometry analysis of the RNA extracted from rings after RNase A treatment showed two peaks of 22,900 and 24,820 Da, corresponding to a mean RNA length of 67 and 73 bases, respectively. These results suggest strongly that each N subunit contacts 6 nt, with an extra three or four bases further protected from nuclease digestion by the ring structure at both the 5' and 3' ends.
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Affiliation(s)
- Thi-Lan Tran
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - Nathalie Castagné
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - David Bhella
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, UK
| | - Paloma F Varela
- Laboratoire de Virologie Moléculaire et Structurale, UMR 2472-1157 CNRS-INRA and IFR 115, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
| | - Julie Bernard
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - Stefan Chilmonczyk
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - Stefan Berkenkamp
- Institute of Medical Physics and Biophysics, Westfälische Wilhelms-Universität, Münster, Germany
| | - Vanessa Benhamo
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - Katarina Grznarova
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - Jeanne Grosclaude
- Unité de Virologie et Immunologie Moléculaires, INRA, 78350 Jouy-en-Josas, France
| | - Claude Nespoulos
- Unité de Biochimie et Structure des Protéines, INRA, 78350 Jouy-en-Josas, France
| | - Felix A Rey
- Laboratoire de Virologie Moléculaire et Structurale, UMR 2472-1157 CNRS-INRA and IFR 115, 1 Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
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41
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Pettigrew DM, Williams DT, Kerrigan D, Evans DJ, Lea SM, Bhella D. Structural and Functional Insights into the Interaction of Echoviruses and Decay-accelerating Factor. J Biol Chem 2006; 281:5169-77. [PMID: 16272562 DOI: 10.1074/jbc.m510362200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many enteroviruses bind to the complement control protein decay-accelerating factor (DAF) to facilitate cell entry. We present here a structure for echovirus (EV) type 12 bound to DAF using cryo-negative stain transmission electron microscopy and three-dimensional image reconstruction to 16-A resolution, which we interpreted using the atomic structures of EV11 and DAF. DAF binds to a hypervariable region of the capsid close to the 2-fold symmetry axes in an interaction that involves mostly the short consensus repeat 3 domain of DAF and the capsid protein VP2. A bulge in the density for the short consensus repeat 3 domain suggests that a loop at residues 174-180 rearranges to prevent steric collision between closely packed molecules at the 2-fold symmetry axes. Detailed analysis of receptor interactions between a variety of echoviruses and DAF using surface plasmon resonance and comparison of this structure (and our previous work; Bhella, D., Goodfellow, I. G., Roversi, P., Pettigrew, D., Chaudhry, Y., Evans, D. J., and Lea, S. M. (2004) J. Biol. Chem. 279, 8325-8332) with reconstructions published for EV7 bound to DAF support major differences in receptor recognition among these viruses. However, comparison of the electron density for the two virus.receptor complexes (rather than comparisons of the pseudo-atomic models derived from fitting the coordinates into these densities) suggests that the dramatic differences in interaction affinities/specificities may arise from relatively subtle structural differences rather than from large-scale repositioning of the receptor with respect to the virus surface.
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MESH Headings
- CD55 Antigens/metabolism
- Capsid Proteins/chemistry
- Capsid Proteins/metabolism
- Cell Line, Tumor
- Cryoelectron Microscopy
- Databases, Protein
- Electrons
- Enterovirus B, Human/chemistry
- Enterovirus B, Human/metabolism
- Humans
- Image Processing, Computer-Assisted
- Microscopy, Electron
- Microscopy, Electron, Transmission
- Microscopy, Video
- Models, Molecular
- Pichia
- Protein Binding
- Protein Conformation
- Receptors, Virus/chemistry
- Recombinant Proteins/chemistry
- Rhabdomyosarcoma/metabolism
- Stereoisomerism
- Surface Plasmon Resonance
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Affiliation(s)
- David M Pettigrew
- Medical Research Council Virology Unit, Institute of Biomedical and Life Sciences, University of Glasgow, Scotland, United Kingdom
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42
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Bhella D, Ralph A, Yeo RP. Conformational flexibility in recombinant measles virus nucleocapsids visualised by cryo-negative stain electron microscopy and real-space helical reconstruction. J Mol Biol 2004; 340:319-31. [PMID: 15201055 DOI: 10.1016/j.jmb.2004.05.015] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2004] [Revised: 04/15/2004] [Accepted: 05/05/2004] [Indexed: 11/27/2022]
Abstract
Measles virus is a highly contagious virus that, despite the existence of an effective vaccine, is a major cause of illness and mortality worldwide. The virus has a negative-sense, single-stranded RNA genome that is encapsidated by the nucleocapsid protein (N) to form a helical ribonucleoprotein complex known as the nucleocapsid. This structure serves as the template for both transcription and replication. Paramyxovirus nucleocapsids are flexible structures, a trait that has hitherto hampered structural analysis even at low resolution. We have investigated the extent of this structural plasticity, using real-space methods to calculate three-dimensional reconstructions of recombinant nucleocapsids from cryo-negative stain transmission electron micrographs. Images of short sections of helix were sorted according to both pitch (the axial rise per turn) and twist (the number of subunits per turn). Our analysis indicates that there is extensive conformational flexibility within these structures, ranging in pitch from 50 Angstrom to 66 Angstrom, while twist varies from at least 13.04 to 13.44 with a greater number of helices comprising around 13.1 subunits per turn. We have also investigated the influence of the C terminus of N on helix conformation, analysing nucleocapsids after having removed this domain by trypsin digestion. We have found that this causes a marked change in both pitch and twist, such that the pitch becomes shorter, ranging from 46 Angstrom to 52 Angstrom, while more helices have a twist of approximately 13.3 subunits per turn. Our findings lead us to propose a mechanism whereby changes in conformation, influenced by interactions between viral or host proteins and the C terminus of N, might have a role in regulating the balance of transcription and replication during virus infection.
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Affiliation(s)
- David Bhella
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, Scotland, UK.
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43
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Bhella D, Goodfellow IG, Roversi P, Pettigrew D, Chaudhry Y, Evans DJ, Lea SM. The Structure of Echovirus Type 12 Bound to a Two-domain Fragment of Its Cellular Attachment Protein Decay-accelerating Factor (CD 55). J Biol Chem 2004; 279:8325-32. [PMID: 14634014 DOI: 10.1074/jbc.m311334200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Echovirus type 12 (EV12), an Enterovirus of the Picornaviridae family, uses the complement regulator decay-accelerating factor (DAF, CD55) as a cellular receptor. We have calculated a three-dimensional reconstruction of EV12 bound to a fragment of DAF consisting of short consensus repeat domains 3 and 4 from cryo-negative stain electron microscopy data (EMD code 1057). This shows that, as for an earlier reconstruction of the related echovirus type 7 bound to DAF, attachment is not within the viral canyon but occurs close to the 2-fold symmetry axes. Despite this general similarity our reconstruction reveals a receptor interaction that is quite different from that observed for EV7. Fitting of the crystallographic co-ordinates for DAF(34) and EV11 into the reconstruction shows a close agreement between the crystal structure of the receptor fragment and the density for the virus-bound receptor, allowing unambiguous positioning of the receptor with respect to the virion (PDB code 1UPN). Our finding that the mode of virus-receptor interaction in EV12 is distinct from that seen for EV7 raises interesting questions regarding the evolution and biological significance of the DAF binding phenotype in these viruses.
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Affiliation(s)
- David Bhella
- Medical Research Council Virology Unit, Church Street, Glasgow, G11 5JR, United Kingdom.
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44
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Gourlay LJ, Bhella D, Kelly SM, Price NC, Lindsay JG. Structure-function analysis of recombinant substrate protein 22 kDa (SP-22). A mitochondrial 2-CYS peroxiredoxin organized as a decameric toroid. J Biol Chem 2003; 278:32631-7. [PMID: 12773537 DOI: 10.1074/jbc.m303862200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bovine mitochondrial SP-22 is a member of the peroxiredoxin family of peroxidases. It belongs to the peroxiredoxin 2-Cys subgroup containing three cysteines at positions 47, 66, and 168. The cloning and overexpression in Escherichia coli of recombinant wild type SP-22 and its three cysteine mutants (C47S, C66S, and C168S) are reported. Purified His-tagged SP-22 was fully active with Cys-47 being confirmed as the catalytic residue. The enzyme forms a stable decameric toroid consisting of five basic dimeric units containing intermolecular disulfide bonds linking the catalytically active Cys-47 of one subunit and Cys-168 of the adjacent monomer. The disulfide bonds are not required for overall structural integrity. The toroidal units have average external and internal diameters of 15 and 7 nm, respectively, and can form stacks in a lateral arrangement of two or three rings. C47S had a pronounced tendency to stack in long tubular structures containing up to 60 rings. Further unusual structural features are the presence of radial spikes projecting from the external surface and ordered electron-dense material within the central cavity of the toroid.
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Affiliation(s)
- Louise J Gourlay
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
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45
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Longhi S, Receveur-Bréchot V, Karlin D, Johansson K, Darbon H, Bhella D, Yeo R, Finet S, Canard B. The C-terminal domain of the measles virus nucleoprotein is intrinsically disordered and folds upon binding to the C-terminal moiety of the phosphoprotein. J Biol Chem 2003; 278:18638-48. [PMID: 12621042 DOI: 10.1074/jbc.m300518200] [Citation(s) in RCA: 235] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nucleoprotein of measles virus consists of an N-terminal moiety, N(CORE), resistant to proteolysis and a C-terminal moiety, N(TAIL), hypersensitive to proteolysis and not visible as a distinct domain by electron microscopy. We report the bacterial expression, purification, and characterization of measles virus N(TAIL). Using nuclear magnetic resonance, circular dichroism, gel filtration, dynamic light scattering, and small angle x-ray scattering, we show that N(TAIL) is not structured in solution. Its sequence and spectroscopic and hydrodynamic properties indicate that N(TAIL) belongs to the premolten globule subfamily within the class of intrinsically disordered proteins. The same epitopes are exposed in N(TAIL) and within the nucleoprotein, which rules out dramatic conformational changes in the isolated N(TAIL) domain compared with the full-length nucleoprotein. Most unstructured proteins undergo some degree of folding upon binding to their partners, a process termed "induced folding." We show that N(TAIL) is able to bind its physiological partner, the phosphoprotein, and that it undergoes such an unstructured-to-structured transition upon binding to the C-terminal moiety of the phosphoprotein. The presence of flexible regions at the surface of the viral nucleocapsid would enable plastic interactions with several partners, whereas the gain of structure arising from induced folding would lead to modulation of these interactions. These results contribute to the study of the emerging field of natively unfolded proteins.
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Affiliation(s)
- Sonia Longhi
- Architecture et Fonction des Macromolécules Biologiques, UMR 6098 CNRS et Université Aix-Marseille I et II, ESIL, Campus de Luminy, 13288 Marseille Cedex 09, France.
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46
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Murphy LB, Loney C, Murray J, Bhella D, Ashton P, Yeo RP. Investigations into the amino-terminal domain of the respiratory syncytial virus nucleocapsid protein reveal elements important for nucleocapsid formation and interaction with the phosphoprotein. Virology 2003; 307:143-53. [PMID: 12667822 DOI: 10.1016/s0042-6822(02)00063-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacterially expressed nucleocapsid (N) protein, from respiratory syncytial virus (RSV), was used to investigate RNA binding in a modified North-Western blotting protocol. The recombinant protein demonstrated no sequence specificity in binding RNA representing either the antigenomic leader sequence or the nonspecific sequence derived from a plasmid vector. When recombinant N was purified on CsCl gradients, two types of structure, both with densities indicating that they contained RNA, could be visualised by negative-stain electron microscopy. Structures similar to nucleocapsids (NC) from RSV-infected cells were observed, as were ring structures. A small fragment of the N (amino acids 1-92) was all that was required for the production of NC-like structures. Another mutant with an internal deletion could form rings but not NC-like structures. This suggests that this domain (amino acids 121-160) may be important for maintaining helical stability. Further analysis has also identified a potential site in the amino-terminus that may be involved in an interaction with the phosphoprotein. A domain model of the RSV N protein is presented which, similar to that of other paramyxoviruses, supports the idea that the amino-terminus is important for NC assembly.
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Affiliation(s)
- Lindsay B Murphy
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, Scotland, UK
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47
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Clayton RF, Owsianka A, Aitken J, Graham S, Bhella D, Patel AH. Analysis of antigenicity and topology of E2 glycoprotein present on recombinant hepatitis C virus-like particles. J Virol 2002; 76:7672-82. [PMID: 12097581 PMCID: PMC136371 DOI: 10.1128/jvi.76.15.7672-7682.2002] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Purification of hepatitis C virus (HCV) from sera of infected patients has proven elusive, hampering efforts to perform structure-function analysis of the viral components. Recombinant forms of the viral glycoproteins have been used instead for functional studies, but uncertainty exists as to whether they closely mimic the virion proteins. Here, we used HCV virus-like particles (VLPs) generated in insect cells infected with a recombinant baculovirus expressing viral structural proteins. Electron microscopic analysis revealed a population of pleomorphic VLPs that were at least partially enveloped with bilayer membranes and had viral glycoprotein spikes protruding from the surface. Immunogold labeling using specific monoclonal antibodies (MAbs) demonstrated these protrusions to be the E1 and E2 glycoproteins. A panel of anti-E2 MAbs was used to probe the surface topology of E2 on the VLPs and to compare the antigenicity of the VLPs with that of truncated E2 (E2(660)) or the full-length (FL) E1E2 complex expressed in mammalian cells. While most MAbs bound to all forms of antigen, a number of others showed striking differences in their abilities to recognize the various E2 forms. All MAbs directed against hypervariable region 1 (HVR-1) recognized both native and denatured E2(660) with comparable affinities, but most bound either weakly or not at all to the FL E1E2 complex or to VLPs. HVR-1 on VLPs was accessible to these MAbs only after denaturation. Importantly, a subset of MAbs specific for amino acids 464 to 475 and 524 to 535 recognized E2(660) but not VLPs or FL E1E2 complex. The antigenic differences between E2(660,) FL E1E2, and VLPs strongly point to the existence of structural differences, which may have functional relevance. Trypsin treatment of VLPs removed the N-terminal part of E2, resulting in a 42-kDa fragment. In the presence of detergent, this was further reduced to a trypsin-resistant 25-kDa fragment, which could be useful for structural studies.
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Affiliation(s)
- Reginald F Clayton
- MRC Virology Unit, Institute of Virology. IBLS, University of Glasgow, Glasgow G11 5JR, United Kingdom
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48
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McClelland DA, Aitken JD, Bhella D, McNab D, Mitchell J, Kelly SM, Price NC, Rixon FJ. pH reduction as a trigger for dissociation of herpes simplex virus type 1 scaffolds. J Virol 2002; 76:7407-17. [PMID: 12097553 PMCID: PMC136365 DOI: 10.1128/jvi.76.15.7407-7417.2002] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2002] [Accepted: 04/24/2002] [Indexed: 11/20/2022] Open
Abstract
Assembly of the infectious herpes simplex virus type 1 virion is a complex, multistage process that begins with the production of a procapsid, which is formed by the condensation of capsid shell proteins around an internal scaffold fashioned from multiple copies of the scaffolding protein, pre-VP22a. The ability of pre-VP22a to interact with itself is an essential feature of this process. However, this self-interaction must subsequently be reversed to allow the scaffolding proteins to exit from the capsid to make room for the viral genome to be packaged. The nature of the process by which dissociation of the scaffold is accomplished is unknown. Therefore, to investigate this process, the properties of isolated scaffold particles were investigated. Electron microscopy and gradient sedimentation studies showed that the particles could be dissociated by low concentrations of chaotropic agents and by moderate reductions in pH (from 7.2 to 5.5). Fluorescence spectroscopy and circular dichroism analyses revealed that there was relatively little change in tertiary and secondary structures under these conditions, indicating that major structural transformations are not required for the dissociation process. We suggest the possibility that dissociation of the scaffold may be triggered by a reduction in pH brought about by the entry of the viral DNA into the capsid.
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Affiliation(s)
- David A McClelland
- MRC Virology Unit, Faculty of Biomedical and Life Sciences, University of Glasgow, Scotland, United Kingdom
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49
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Abstract
Nucleocapsid (N) proteins from representative viruses of three genera within the Paramyxoviridae were expressed in insect cells using recombinant baculoviruses. RNA-containing structures, which appear morphologically identical to viral nucleocapsids, were isolated and subsequently imaged under a transmission electron microscope. Analysis of these images revealed marked differences in nucleocapsid morphology among the genera investigated, most notably between viruses of the Paramyxovirinae and the Pneumovirinae subfamilies. Helical pitch measurements were made, revealing that measles virus (MV, a Morbillivirus within the subfamily Paramyxovirinae) N protein produces helices that adopt multiple conformations with varying degrees of flexibility, while that of the Rubulavirus simian virus type 5 (SV5, subfamily Paramyxovirinae) produces more rigid structures with a less heterogeneous pitch distribution. Nucleocapsids produced by respiratory syncytial virus (RSV, subfamily Pneumovirinae) appear significantly narrower than those of MV and SV5 and have a longer pitch than the most extended form of MV. In addition to helical nucleocapsids, ring structures were also produced, image analysis of which has demonstrated that rings assembled from MV N protein consist of 13 subunits. This is consistent with previous reports that Sendai virus nucleocapsids have 13.07 subunits per turn. It was determined, however, that SV5 subnucleocapsid rings have 14 subunits, while rings derived from the radically different RSV nucleocapsid have been found to contain predominantly 10 subunits.
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Affiliation(s)
- David Bhella
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, UK1
| | - Adam Ralph
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, UK1
| | - Lindsay B Murphy
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, UK1
| | - Robert P Yeo
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, UK1
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50
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Bhella D, Rixon FJ, Dargan DJ. Cryomicroscopy of human cytomegalovirus virions reveals more densely packed genomic DNA than in herpes simplex virus type 1. J Mol Biol 2000; 295:155-61. [PMID: 10623515 DOI: 10.1006/jmbi.1999.3344] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
All members of the herpesvirus family have a characteristic virion structure, comprising a DNA containing, icosahedral capsid, embedded in a proteinaceous layer (tegument) and surrounded by a lipid envelope. Human cytomegalovirus (HCMV, the prototypic beta-herpesvirus) has a genome that is significantly larger (>50 %) than that of the alpha-herpesvirus HSV-1. Although the internal volume of the HCMV capsid is approximately 17 % larger than that of HSV-1, this slight increase in volume does not provide adequate space to encapsidate the full length HCMV genome at the same packing density as HSV-1. We have investigated the nature of DNA packing in HCMV and HSV-1 virions by electron-cryomicroscopy and image processing. Radial density profiles calculated from projection images of HCMV and HSV-1 capsids suggest that there is no increase in the volume of the HCMV capsid upon DNA packaging. Packing density of the viral DNA was assessed for both HCMV and HSV-1 by image analysis of both full and empty particles. Our results for packing density in HSV-1 are in good agreement with previously published measurements, showing an average inter-layer spacing of approximately 26 A. Measurements taken from our HCMV images, however, suggest that the viral genomic DNA is more densely packed, with an average inter-layer spacing of approximately 23 A. We propose therefore, that the combination of greater volume in HCMV capsids and increased packing density of viral DNA accounts for its ability to encapsidate a large genome.
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Affiliation(s)
- D Bhella
- Medical Research Council Virology Unit, Church Street, Glasgow, G11 5JR, United Kingdom.
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