1
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Döhner K, Serrero MC, Sodeik B. The role of nuclear pores and importins for herpes simplex virus infection. Curr Opin Virol 2023; 62:101361. [PMID: 37672874 DOI: 10.1016/j.coviro.2023.101361] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 07/31/2023] [Accepted: 08/08/2023] [Indexed: 09/08/2023]
Abstract
Microtubule transport and nuclear import are functionally connected, and the nuclear pore complex (NPC) can interact with microtubule motors. For several alphaherpesvirus proteins, nuclear localization signals (NLSs) and their interactions with specific importin-α proteins have been characterized. Here, we review recent insights on the roles of microtubule motors, capsid-associated NLSs, and importin-α proteins for capsid transport, capsid docking to NPCs, and genome release into the nucleoplasm, as well as the role of importins for nuclear viral transcription, replication, capsid assembly, genome packaging, and nuclear capsid egress. Moreover, importin-α proteins exert antiviral effects by promoting the nuclear import of transcription factors inducing the expression of interferons (IFN), cytokines, and IFN-stimulated genes, and the IFN-inducible MxB restricts capsid docking to NPCs.
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Affiliation(s)
- Katinka Döhner
- Institute of Virology, Hannover Medical School, Hannover, Germany; Department of Dermatology and Allergy, Hannover Medical School, Hannover, Germany; RESIST - Cluster of Excellence, Hannover Medical School, Hannover, Germany.
| | - Manutea C Serrero
- Institute of Virology, Hannover Medical School, Hannover, Germany; RESIST - Cluster of Excellence, Hannover Medical School, Hannover, Germany
| | - Beate Sodeik
- Institute of Virology, Hannover Medical School, Hannover, Germany; RESIST - Cluster of Excellence, Hannover Medical School, Hannover, Germany; DZIF - German Centre for Infection Research, Braunschweig, Hannover, Germany.
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2
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Borst EM, Harmening S, Sanders S, Caragliano E, Wagner K, Lenac Roviš T, Jonjić S, Bosse JB, Messerle M. A Unique Role of the Human Cytomegalovirus Small Capsid Protein in Capsid Assembly. mBio 2022; 13:e0100722. [PMID: 36066102 PMCID: PMC9600257 DOI: 10.1128/mbio.01007-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/11/2022] [Indexed: 11/20/2022] Open
Abstract
Morphogenesis of herpesvirus particles is highly conserved; however, the capsid assembly and genome packaging of human cytomegalovirus (HCMV) exhibit unique features. Examples of these include the essential role of the small capsid protein (SCP) and the existence of the β-herpesvirus-specific capsid-associated protein pp150. SCP and pp150, as well as the UL77 and UL93 proteins, are important capsid constituents, yet their precise mechanism of action is elusive. Here, we analyzed how deletion of the open reading frames (ORFs) encoding pUL77, pUL93, pp150, or SCP affects the protein composition of nuclear capsids. This was achieved by generating HCMV genomes lacking the respective genes, combined with a highly efficient transfection technique that allowed us to directly analyze these mutants in transfected cells. While no obvious effects were observed when pUL77, pUL93, or pp150 was missing, the absence of SCP impeded capsid assembly due to strongly reduced amounts of major capsid protein (MCP). Vice versa, when MCP was lacking, SCP became undetectable, indicating a mutual dependence of SCP and MCP for establishing appropriate protein levels. The SCP domain mediating stable MCP levels could be narrowed down to a C-terminal helix known to convey MCP binding. Interestingly, an SCP-EGFP (enhanced green fluorescent protein) fusion protein which also impaired the production of infectious progeny acted in a different manner, as capsid assembly was not abolished; however, SCP-EGFP-harboring capsids were devoid of DNA and trapped in paracrystalline nuclear structures. These results indicate that SCP is essential in HCMV because of its impact on MCP levels and reveal SCP as a potential target for antiviral inhibitors. IMPORTANCE Human cytomegalovirus (HCMV) is a ubiquitous pathogen causing life-threatening disease in immunocompromised individuals. Virus-specific processes such as capsid assembly and genome packaging can be exploited to design new antiviral strategies. Here, we report on a novel function of the HCMV small capsid protein (SCP), namely, ensuring stable levels of major capsid protein (MCP), thereby governing capsid assembly. Furthermore, we discovered a mutual dependence of the small and major capsid proteins to guarantee appropriate levels of the other respective protein and were able to pin down the SCP domain responsible for this effect to a region previously shown to mediate binding to the major capsid protein. In summary, our data contribute to the understanding of how SCP plays an essential part in the HCMV infection cycle. Moreover, disrupting the SCP-MCP interface may provide a starting point for the development of novel antiviral drugs.
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Affiliation(s)
- Eva Maria Borst
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Sarah Harmening
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Saskia Sanders
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Enrico Caragliano
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Karen Wagner
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Tihana Lenac Roviš
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jens Bernhard Bosse
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Department of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research, Partner Site Hannover Braunschweig, Hannover, Germany
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3
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Tegument Protein pp150 Sequence-Specific Peptide Blocks Cytomegalovirus Infection. Viruses 2021; 13:v13112277. [PMID: 34835083 PMCID: PMC8623180 DOI: 10.3390/v13112277] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 11/17/2022] Open
Abstract
Human cytomegalovirus (HCMV) tegument protein pp150 is essential for the completion of the final steps in virion maturation. Earlier studies indicated that three pp150nt (N-terminal one-third of pp150) conformers cluster on each triplex (Tri1, Tri2A and Tri2B), and extend towards small capsid proteins atop nearby major capsid proteins, forming a net-like layer of tegument densities that enmesh and stabilize HCMV capsids. Based on this atomic detail, we designed several peptides targeting pp150nt. Our data show significant reduction in virus growth upon treatment with one of these peptides (pep-CR2) with an IC50 of 1.33 μM and no significant impact on cell viability. Based on 3D modeling, pep-CR2 specifically interferes with the pp150–capsid binding interface. Cells pre-treated with pep-CR2 and infected with HCMV sequester pp150 in the nucleus, indicating a mechanistic disruption of pp150 loading onto capsids and subsequent nuclear egress. Furthermore, pep-CR2 effectively inhibits mouse cytomegalovirus (MCMV) infection in cell culture, paving the way for future animal testing. Combined, these results indicate that CR2 of pp150 is amenable to targeting by a peptide inhibitor, and can be developed into an effective antiviral.
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4
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Naniima P, Naimo E, Koch S, Curth U, Alkharsah KR, Ströh LJ, Binz A, Beneke JM, Vollmer B, Böning H, Borst EM, Desai P, Bohne J, Messerle M, Bauerfeind R, Legrand P, Sodeik B, Schulz TF, Krey T. Assembly of infectious Kaposi's sarcoma-associated herpesvirus progeny requires formation of a pORF19 pentamer. PLoS Biol 2021; 19:e3001423. [PMID: 34735435 PMCID: PMC8568140 DOI: 10.1371/journal.pbio.3001423] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 09/22/2021] [Indexed: 12/25/2022] Open
Abstract
Herpesviruses cause severe diseases particularly in immunocompromised patients. Both genome packaging and release from the capsid require a unique portal channel occupying one of the 12 capsid vertices. Here, we report the 2.6 Å crystal structure of the pentameric pORF19 of the γ-herpesvirus Kaposi’s sarcoma-associated herpesvirus (KSHV) resembling the portal cap that seals this portal channel. We also present the structure of its β-herpesviral ortholog, revealing a striking structural similarity to its α- and γ-herpesviral counterparts despite apparent differences in capsid association. We demonstrate pORF19 pentamer formation in solution and provide insights into how pentamerization is triggered in infected cells. Mutagenesis in its lateral interfaces blocked pORF19 pentamerization and severely affected KSHV capsid assembly and production of infectious progeny. Our results pave the way to better understand the role of pORF19 in capsid assembly and identify a potential novel drug target for the treatment of herpesvirus-induced diseases. In herpesviruses, genome packaging and release from the capsid require a unique portal channel. Here, the authors have resolved the crystal structure of a pentameric KSHV pORF19 assembly and find that it resembles the herpesviral portal cap and provides insights how the viral genome is retained within the capsid.
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Affiliation(s)
- Peter Naniima
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
| | - Eleonora Naimo
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
| | - Ute Curth
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Khaled R. Alkharsah
- Department of Microbiology, College of Medicine, Imam Abdulrahman Bin Faisal University (IAU), Dammam, Saudi Arabia
| | - Luisa J. Ströh
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Anne Binz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Jan-Marc Beneke
- Center of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Luebeck, Luebeck, Germany
| | - Benjamin Vollmer
- Centre for Structural Systems Biology, Leibniz-Institut für Experimentelle Virologie (HPI), Hamburg, Germany
| | - Heike Böning
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Eva Maria Borst
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Prashant Desai
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jens Bohne
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Rudolf Bauerfeind
- Research Core Unit Laser Microscopy, Hannover Medical School, Hannover, Germany
| | - Pierre Legrand
- Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette, France
| | - Beate Sodeik
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Thomas Krey
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
- Center of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Luebeck, Luebeck, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- * E-mail:
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5
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Draganova EB, Valentin J, Heldwein EE. The Ins and Outs of Herpesviral Capsids: Divergent Structures and Assembly Mechanisms across the Three Subfamilies. Viruses 2021; 13:v13101913. [PMID: 34696343 PMCID: PMC8539031 DOI: 10.3390/v13101913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 12/17/2022] Open
Abstract
Human herpesviruses, classified into three subfamilies, are double-stranded DNA viruses that establish lifelong latent infections within most of the world’s population and can cause severe disease, especially in immunocompromised people. There is no cure, and current preventative and therapeutic options are limited. Therefore, understanding the biology of these viruses is essential for finding new ways to stop them. Capsids play a central role in herpesvirus biology. They are sophisticated vehicles that shelter the pressurized double-stranded-DNA genomes while ensuring their delivery to defined cellular destinations on the way in and out of the host cell. Moreover, the importance of capsids for multiple key steps in the replication cycle makes their assembly an attractive therapeutic target. Recent cryo-electron microscopy reconstructions of capsids from all three subfamilies of human herpesviruses revealed not only conserved features but also remarkable structural differences. Furthermore, capsid assembly studies have suggested subfamily-specific roles of viral capsid protein homologs. In this review, we compare capsid structures, assembly mechanisms, and capsid protein functions across human herpesvirus subfamilies, highlighting the differences.
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Affiliation(s)
- Elizabeth B. Draganova
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA;
| | - Jonathan Valentin
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32603, USA;
| | - Ekaterina E. Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA;
- Correspondence:
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6
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Structure of human cytomegalovirus virion reveals host tRNA binding to capsid-associated tegument protein pp150. Nat Commun 2021; 12:5513. [PMID: 34535641 PMCID: PMC8448752 DOI: 10.1038/s41467-021-25791-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
Under the Baltimore nucleic acid-based virus classification scheme, the herpesvirus human cytomegalovirus (HCMV) is a Class I virus, meaning that it contains a double-stranded DNA genome-and no RNA. Here, we report sub-particle cryoEM reconstructions of HCMV virions at 2.9 Å resolution revealing structures resembling non-coding transfer RNAs (tRNAs) associated with the virion's capsid-bound tegument protein, pp150. Through deep sequencing, we show that these RNA sequences match human tRNAs, and we built atomic models using the most abundant tRNA species. Based on our models, tRNA recruitment is mediated by the electrostatic interactions between tRNA phosphate groups and the helix-loop-helix motif of HCMV pp150. The specificity of these interactions may explain the absence of such tRNA densities in murine cytomegalovirus and other human herpesviruses.
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7
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The journey of herpesvirus capsids and genomes to the host cell nucleus. Curr Opin Virol 2021; 50:147-158. [PMID: 34464845 DOI: 10.1016/j.coviro.2021.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 01/04/2023]
Abstract
Starting a herpesviral infection is a steeplechase across membranes, cytosol, and nuclear envelopes and against antiviral defence mechanisms. Here, we highlight recent insights on capsid stabilization at the portals during assembly, early capsid-host interactions ensuring nuclear targeting of incoming capsids, and genome uncoating. After fusion with a host membrane, incoming capsids recruit microtubule motors for traveling to the centrosome, and by unknown mechanisms get forward towards the nucleus. The interaction of capsid-associated tegument proteins with nucleoporins orients the capsid portal towards the nuclear pore, and presumably after removal of the portal caps the genomes that have been packaged under pressure can be injected into the nucleoplasm for transcription and replication. Some cell types disarm the incoming capsids or silence the incoming genomes to reduce the likelihood of infection.
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8
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Structural basis for genome packaging, retention, and ejection in human cytomegalovirus. Nat Commun 2021; 12:4538. [PMID: 34315863 PMCID: PMC8316551 DOI: 10.1038/s41467-021-24820-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/12/2021] [Indexed: 12/27/2022] Open
Abstract
How the human cytomegalovirus (HCMV) genome—the largest among human herpesviruses—is packaged, retained, and ejected remains unclear. We present the in situ structures of the symmetry-mismatched portal and the capsid vertex-specific components (CVSCs) of HCMV. The 5-fold symmetric 10-helix anchor—uncommon among known portals—contacts the portal-encircling DNA, which is presumed to squeeze the portal as the genome packaging proceeds. We surmise that the 10-helix anchor dampens this action to delay the portal reaching a “head-full” packaging state, thus facilitating the large genome to be packaged. The 6-fold symmetric turret, latched via a coiled coil to a helix from a major capsid protein, supports the portal to retain the packaged genome. CVSCs at the penton vertices—presumed to increase inner capsid pressure—display a low stoichiometry, which would aid genome retention. We also demonstrate that the portal and capsid undergo conformational changes to facilitate genome ejection after viral cell entry. Human cytomegalovirus (HCMV) is the prototypical member of the β-herpesvirinae subfamily and the leading viral cause of congenital infections that can lead to birth defects and it can also cause life-threatening disease in immunocompromised individuals. Here, the authors present the in-situ cryo-EM structures of the symmetry-mismatched portal and the capsid vertex-specific components (CVSCs) of HCMV and discuss the mechanistic implications for genome package, retention and ejection.
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9
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Liu W, Cui Y, Wang C, Li Z, Gong D, Dai X, Bi GQ, Sun R, Zhou ZH. Structures of capsid and capsid-associated tegument complex inside the Epstein-Barr virus. Nat Microbiol 2020; 5:1285-1298. [PMID: 32719506 DOI: 10.1038/s41564-020-0758-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 06/19/2020] [Indexed: 12/20/2022]
Abstract
As the first discovered human cancer virus, Epstein-Barr virus (EBV) causes Burkitt's lymphoma and nasopharyngeal carcinoma. Isolating virions for determining high-resolution structures has been hindered by latency-a hallmark of EBV infection-and atomic structures are thus available only for recombinantly expressed EBV proteins. In the present study, by symmetry relaxation and subparticle reconstruction, we have determined near-atomic-resolution structures of the EBV capsid with an asymmetrically attached DNA-translocating portal and capsid-associated tegument complexes from cryogenic electron microscopy images of just 2,048 EBV virions obtained by chemical induction. The resulting atomic models reveal structural plasticity among the 20 conformers of the major capsid protein, 2 conformers of the small capsid protein (SCP), 4 conformers of the triplex monomer proteins and 2 conformers of the triplex dimer proteins. Plasticity reaches the greatest level at the capsid-tegument interfaces involving SCP and capsid-associated tegument complexes (CATC): SCPs crown pentons/hexons and mediate tegument protein binding, and CATCs bind and rotate all five periportal triplexes, but notably only about one peri-penton triplex. These results offer insights into the EBV capsid assembly and a mechanism for recruiting cell-regulating factors into the tegument compartment as 'cargoes', and should inform future anti-EBV strategies.
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Affiliation(s)
- Wei Liu
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Microbiology Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.,Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA
| | - Caiyan Wang
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Microbiology Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.,International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zihang Li
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Microbiology Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA
| | - Danyang Gong
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Therapeutics Discovery, Amgen Research, Amgen Inc., Thousand Oaks, CA, USA
| | - Xinghong Dai
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Microbiology Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Guo-Qiang Bi
- Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ren Sun
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA.,Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, USA. .,Department of Microbiology Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, USA.
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10
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Li Z, Zhang X, Dong L, Pang J, Xu M, Zhong Q, Zeng MS, Yu X. CryoEM structure of the tegumented capsid of Epstein-Barr virus. Cell Res 2020; 30:873-884. [PMID: 32620850 PMCID: PMC7608217 DOI: 10.1038/s41422-020-0363-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 06/16/2020] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus (EBV) is the primary cause of infectious mononucleosis and has been shown to be closely associated with various malignancies. Here, we present a complete atomic model of EBV, including the icosahedral capsid, the dodecameric portal and the capsid-associated tegument complex (CATC). Our in situ portal from the tegumented capsid adopts a closed conformation with its channel valve holding the terminal viral DNA and with its crown region firmly engaged by three layers of ring-like dsDNA, which, together with the penton flexibility, effectively alleviates the capsid inner pressure placed on the portal cap. In contrast, the CATCs, through binding to the flexible penton vertices in a stoichiometric manner, accurately increase the inner capsid pressure to facilitate the pressure-driven genome delivery. Together, our results provide important insights into the mechanism by which the EBV capsid, portal, packaged genome and the CATCs coordinately achieve a pressure balance to simultaneously benefit both viral genome retention and ejection.
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Affiliation(s)
- Zhihai Li
- Cryo-Electron Microscopy Research Center, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Xiao Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060, China
| | - Lili Dong
- Cryo-Electron Microscopy Research Center, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Jingjing Pang
- Cryo-Electron Microscopy Research Center, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Miao Xu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060, China
| | - Qian Zhong
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060, China
| | - Mu-Sheng Zeng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Department of Experimental Research, Sun Yat-sen University Cancer Center, Sun Yat-sen University, Guangzhou, Guangdong, 510060, China.
| | - Xuekui Yu
- Cryo-Electron Microscopy Research Center, The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China.
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11
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Abstract
The human betaherpesviruses, human cytomegalovirus (HCMV; species Human betaherpesvirus 5) and human herpesviruses 6A, 6B, and 7 (HHV-6A, -6B, and -7; species Human betaherpesviruses 6A, 6B, and 7) are highly prevalent and can cause severe disease in immune-compromised and immune-naive populations in well- and under-developed communities. Herpesvirus virion assembly is an intricate process that requires viral orchestration of host systems. In this review, we describe recent advances in some of the many cellular events relevant to assembly and egress of betaherpesvirus virions. These include modifications of host metabolic, immune, and autophagic/recycling systems. In addition, we discuss unique aspects of betaherpesvirus virion structure, virion assembly, and the cellular pathways employed during virion egress.
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12
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Goetschius DJ, Lee H, Hafenstein S. CryoEM reconstruction approaches to resolve asymmetric features. Adv Virus Res 2019; 105:73-91. [PMID: 31522709 DOI: 10.1016/bs.aivir.2019.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Although icosahedral viruses have highly symmetrical capsid features, asymmetric structural elements are also present since the genome and minor structural proteins are usually incorporated without adhering to icosahedral symmetry. Besides this inherent asymmetry, interactions with the host during the virus life cycle are also asymmetric. However, until recently it was impossible to resolve high resolution asymmetric features during single-particle cryoEM image processing. This review summarizes the current approaches that can be used to visualize asymmetric structural features. We have included examples of advanced structural strategies developed to reveal unique features and asymmetry in icosahedral viruses.
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Affiliation(s)
- Daniel J Goetschius
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States; Department of Medicine, College of Medicine, The Pennsylvania State University, Hershey, PA, United States
| | - Hyunwook Lee
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States; Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States
| | - Susan Hafenstein
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States; Department of Medicine, College of Medicine, The Pennsylvania State University, Hershey, PA, United States; Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, United States.
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13
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Zhang Y, Liu W, Li Z, Kumar V, Alvarez-Cabrera AL, Leibovitch EC, Cui Y, Mei Y, Bi GQ, Jacobson S, Zhou ZH. Atomic structure of the human herpesvirus 6B capsid and capsid-associated tegument complexes. Nat Commun 2019; 10:5346. [PMID: 31767868 PMCID: PMC6877594 DOI: 10.1038/s41467-019-13064-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 10/09/2019] [Indexed: 12/12/2022] Open
Abstract
Human herpesvirus 6B (HHV-6B) belongs to the β-herpesvirus subfamily of the Herpesviridae. To understand capsid assembly and capsid-tegument interactions, here we report atomic structures of HHV-6B capsid and capsid-associated tegument complex (CATC) obtained by cryoEM and sub-particle reconstruction. Compared to other β-herpesviruses, HHV-6B exhibits high similarity in capsid structure but organizational differences in its CATC (pU11 tetramer). 180 "VΛ"-shaped CATCs are observed in HHV-6B, distinguishing from the 255 "Λ"-shaped dimeric CATCs observed in murine cytomegalovirus and the 310 "Δ"-shaped CATCs in human cytomegalovirus. This trend in CATC quantity correlates with the increasing genomes sizes of these β-herpesviruses. Incompatible distances revealed by the atomic structures rationalize the lack of CATC's binding to triplexes Ta, Tc, and Tf in HHV-6B. Our results offer insights into HHV-6B capsid assembly and the roles of its tegument proteins, including not only the β-herpesvirus-specific pU11 and pU14, but also those conserved across all subfamilies of Herpesviridae.
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Affiliation(s)
- Yibo Zhang
- Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China (USTC), Hefei, Anhui, 230026, China.,California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA
| | - Wei Liu
- Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China (USTC), Hefei, Anhui, 230026, China.,California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA.,Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA, 90095-7364, USA.,State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University (ECNU), Shanghai, 200062, China
| | - Zihang Li
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA.,Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA, 90095-7364, USA
| | - Vinay Kumar
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA.,Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA, 90095-7364, USA
| | - Ana L Alvarez-Cabrera
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA.,Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA, 90095-7364, USA
| | - Emily C Leibovitch
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA
| | - Ye Mei
- State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University (ECNU), Shanghai, 200062, China
| | - Guo-Qiang Bi
- Center for Integrative Imaging, Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China (USTC), Hefei, Anhui, 230026, China
| | - Steve Jacobson
- Viral Immunology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health (NIH), Bethesda, MD, 20892, USA
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, 90095-7151, USA. .,Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA, 90095-7364, USA.
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