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Zhen J, Chen J, Huang H, Liao S, Liu S, Yuan Y, Sun R, Longnecker R, Wu TT, Zhou ZH. Structures of Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus virions reveal species-specific tegument and envelope features. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.09.602672. [PMID: 39026862 PMCID: PMC11257568 DOI: 10.1101/2024.07.09.602672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are classified into the gammaherpesvirus subfamily of Herpesviridae , which stands out from its alpha- and betaherpesvirus relatives due to the tumorigenicity of its members. Although structures of human alpha- and betaherpesviruses by cryogenic electron tomography (cryoET) have been reported, reconstructions of intact human gammaherpesvirus virions remain elusive. Here, we structurally characterize extracellular virions of EBV and KSHV by deep learning-enhanced cryoET, resolving both previously known monomorphic capsid structures and previously unknown pleomorphic features beyond the capsid. Through subtomogram averaging and subsequent tomogram-guided sub-particle reconstruction, we determined the orientation of KSHV nucleocapsids from mature virions with respect to the portal to provide spatial context for the tegument within the virion. Both EBV and KSHV have an eccentric capsid position and polarized distribution of tegument. Tegument species span from the capsid to the envelope and may serve as scaffolds for tegumentation and envelopment. The envelopes of EBV and KSHV are less densely populated with glycoproteins than those of herpes simplex virus 1 and human cytomegalovirus, representative members of alpha- and betaherpesviruses, respectively. This population density of glycoproteins correlates with their relative infectivity against HEK293T cells. Also, we observed fusion protein gB trimers exist within triplet arrangements in addition to standalone complexes, which is relevant to understanding dynamic processes such as fusion pore formation. Taken together, this study reveals nuanced yet important differences in the tegument and envelope architectures among human herpesviruses and provides insights into their varied cell tropism and infection. Importance Discovered in 1964, Epstein-Barr virus (EBV) is the first identified human oncogenic virus and the founding member of the gammaherpesvirus subfamily. In 1994, another cancer-causing virus was discovered in lesions of AIDS patients and later named Kaposi's sarcoma-associated herpesvirus (KSHV), the second human gammaherpesvirus. Despite the historical importance of EBV and KSHV, technical difficulties with isolating large quantities of these viruses and the pleiomorphic nature of their envelope and tegument layers have limited structural characterization of their virions. In this study, we employed the latest technologies in cryogenic electron microscopy (cryoEM) and tomography (cryoET) supplemented with an artificial intelligence-powered data processing software package to reconstruct 3D structures of the EBV and KSHV virions. We uncovered unique properties of the envelope glycoproteins and tegument layers of both EBV and KSHV. Comparison of these features with their non-tumorigenic counterparts provides insights into their relevance during infection.
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Jih J, Liu YT, Liu W, Zhou ZH. The incredible bulk: Human cytomegalovirus tegument architectures uncovered by AI-empowered cryo-EM. SCIENCE ADVANCES 2024; 10:eadj1640. [PMID: 38394211 PMCID: PMC10889378 DOI: 10.1126/sciadv.adj1640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
The compartmentalization of eukaryotic cells presents considerable challenges to the herpesvirus life cycle. The herpesvirus tegument, a bulky proteinaceous aggregate sandwiched between herpesviruses' capsid and envelope, is uniquely evolved to address these challenges, yet tegument structure and organization remain poorly characterized. We use deep-learning-enhanced cryogenic electron microscopy to investigate the tegument of human cytomegalovirus virions and noninfectious enveloped particles (NIEPs; a genome packaging-aborted state), revealing a portal-biased tegumentation scheme. We resolve atomic structures of portal vertex-associated tegument (PVAT) and identify multiple configurations of PVAT arising from layered reorganization of pUL77, pUL48 (large tegument protein), and pUL47 (inner tegument protein) assemblies. Analyses show that pUL77 seals the last-packaged viral genome end through electrostatic interactions, pUL77 and pUL48 harbor a head-linker-capsid-binding motif conducive to PVAT reconfiguration, and pUL47/48 dimers form 45-nm-long filaments extending from the portal vertex. These results provide a structural framework for understanding how herpesvirus tegument facilitates and evolves during processes spanning viral genome packaging to delivery.
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Affiliation(s)
- Jonathan Jih
- Molecular Biology Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Yun-Tao Liu
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Wei Liu
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Z. Hong Zhou
- Molecular Biology Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
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Iwaisako Y, Watanabe T, Suzuki Y, Nakano T, Fujimuro M. Kaposi's Sarcoma-Associated Herpesvirus ORF67.5 Functions as a Component of the Terminase Complex. J Virol 2023; 97:e0047523. [PMID: 37272800 PMCID: PMC10308961 DOI: 10.1128/jvi.00475-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 05/09/2023] [Indexed: 06/06/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a double-stranded DNA (dsDNA) gammaherpesvirus with a poorly characterized lytic replication cycle. However, the lytic replication cycle of the alpha- and betaherpesviruses are well characterized. During lytic infection of alpha- and betaherpesviruses, the viral genome is replicated as a precursor form, which contains tandem genomes linked via terminal repeats (TRs). One genomic unit of the precursor form is packaged into a capsid and is cleaved at the TR by the terminase complex. While the alpha- and betaherpesvirus terminases are well characterized, the KSHV terminase remains poorly understood. KSHV open reading frame 7 (ORF7), ORF29, and ORF67.5 are presumed to be components of the terminase complex based on their homology to other terminase proteins. We previously reported that ORF7-deficient KSHV formed numerous immature soccer ball-like capsids and failed to cleave the TRs. ORF7 interacted with ORF29 and ORF67.5; however, ORF29 and ORF67.5 did not interact with each other. While these results suggested that ORF7 is important for KSHV terminase function and capsid formation, the function of ORF67.5 was completely unknown. Therefore, to analyze the function of ORF67.5, we constructed ORF67.5-deficient BAC16. ORF67.5-deficient KSHV failed to produce infectious virus and cleave the TRs, and numerous soccer ball-like capsids were observed in ORF67.5-deficient KSHV-harboring cells. Furthermore, ORF67.5 promoted the interaction between ORF7 and ORF29, and ORF29 increased the interaction between ORF67.5 and ORF7. Thus, our data indicated that ORF67.5 functions as a component of the KSHV terminase complex by contributing to TR cleavage, terminase complex formation, capsid formation, and virus production. IMPORTANCE Although the formation and function of the alpha- and betaherpesvirus terminase complexes are well understood, the Kaposi's sarcoma-associated herpesvirus (KSHV) terminase complex is still largely uncharacterized. This complex presumably contains KSHV open reading frame 7 (ORF7), ORF29, and ORF67.5. We were the first to report the presence of soccer ball-like capsids in ORF7-deficient KSHV-harboring lytic-induced cells. Here, we demonstrated that ORF67.5-deficient KSHV also formed soccer ball-like capsids in lytic-induced cells. Moreover, ORF67.5 was required for terminal repeat (TR) cleavage, infectious virus production, and enhancement of the interaction between ORF7 and ORF29. ORF67.5 has several highly conserved regions among its human herpesviral homologs. These regions were necessary for virus production and for the interaction of ORF67.5 with ORF7, which was supported by the artificial intelligence (AI)-predicted structure model. Importantly, our results provide the first evidence showing that ORF67.5 is essential for terminase complex formation and TR cleavage.
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Affiliation(s)
- Yuki Iwaisako
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tadashi Watanabe
- Department of Virology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Youichi Suzuki
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - Takashi Nakano
- Department of Microbiology and Infection Control, Faculty of Medicine, Osaka Medical and Pharmaceutical University, Osaka, Japan
| | - Masahiro Fujimuro
- Department of Cell Biology, Kyoto Pharmaceutical University, Kyoto, Japan
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Li Z, Pang J, Gao R, Wang Q, Zhang M, Yu X. Cryo-electron microscopy structures of capsids and in situ portals of DNA-devoid capsids of human cytomegalovirus. Nat Commun 2023; 14:2025. [PMID: 37041152 PMCID: PMC10090080 DOI: 10.1038/s41467-023-37779-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/30/2023] [Indexed: 04/13/2023] Open
Abstract
The portal-scaffold complex is believed to nucleate the assembly of herpesvirus procapsids. During capsid maturation, two events occur: scaffold expulsion and DNA incorporation. The portal-scaffold interaction and the conformational changes that occur to the portal during the different stages of capsid formation have yet to be elucidated structurally. Here we present high-resolution structures of the A- and B-capsids and in-situ portals of human cytomegalovirus. We show that scaffolds bind to the hydrophobic cavities formed by the dimerization and Johnson-fold domains of the major capsid proteins. We further show that 12 loop-helix-loop fragments-presumably from the scaffold domain-insert into the hydrophobic pocket of the portal crown domain. The portal also undergoes significant changes both positionally and conformationally as it accompanies DNA packaging. These findings unravel the mechanism by which the portal interacts with the scaffold to nucleate capsid assembly and further our understanding of scaffold expulsion and DNA incorporation.
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Affiliation(s)
- Zhihai Li
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China
- Cryo-Electron Microscopy Research Center, Chinese Academy of Sciences, Shanghai, 201203, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Jingjing Pang
- Cryo-Electron Microscopy Research Center, Chinese Academy of Sciences, Shanghai, 201203, China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Rongchao Gao
- Cryo-Electron Microscopy Research Center, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Qingxia Wang
- Cryo-Electron Microscopy Research Center, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Maoyan Zhang
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China
| | - Xuekui Yu
- Cryo-Electron Microscopy Research Center, Chinese Academy of Sciences, Shanghai, 201203, China.
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, 100049, Beijing, China.
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210023, Jiangsu, China.
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Lam AK, Roshan R, Miley W, Labo N, Zhen J, Kurland AP, Cheng C, Huang H, Teng PL, Harelson C, Gong D, Tam YK, Radu CG, Epeldegui M, Johnson JR, Zhou ZH, Whitby D, Wu TT. Immunization of Mice with Virus-Like Vesicles of Kaposi Sarcoma-Associated Herpesvirus Reveals a Role for Antibodies Targeting ORF4 in Activating Complement-Mediated Neutralization. J Virol 2023; 97:e0160022. [PMID: 36757205 PMCID: PMC9972917 DOI: 10.1128/jvi.01600-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/11/2023] [Indexed: 02/10/2023] Open
Abstract
Infection by Kaposi sarcoma-associated herpesvirus (KSHV) can cause severe consequences, such as cancers and lymphoproliferative diseases. Whole inactivated viruses (WIV) with chemically destroyed genetic materials have been used as antigens in several licensed vaccines. During KSHV productive replication, virus-like vesicles (VLVs) that lack capsids and viral genomes are generated along with virions. Here, we investigated the immunogenicity of KSHV VLVs produced from a viral mutant that was defective in capsid formation and DNA packaging. Mice immunized with adjuvanted VLVs generated KSHV-specific T cell and antibody responses. Neutralization of KSHV infection by the VLV immune serum was low but was markedly enhanced in the presence of the complement system. Complement-enhanced neutralization and complement deposition on KSHV-infected cells was dependent on antibodies targeting viral open reading frame 4 (ORF4). However, limited complement-mediated enhancement was detected in the sera of a small cohort of KSHV-infected humans which contained few neutralizing antibodies. Therefore, vaccination that induces antibody effector functions can potentially improve infection-induced humoral immunity. Overall, our study highlights a potential benefit of engaging complement-mediated antibody functions in future KSHV vaccine development. IMPORTANCE KSHV is a virus that can lead to cancer after infection. A vaccine that prevents KSHV infection or transmission would be helpful in preventing the development of these cancers. We investigated KSHV VLV as an immunogen for vaccination. We determined that antibodies targeting the viral protein ORF4 induced by VLV immunization could engage the complement system and neutralize viral infection. However, ORF4-specific antibodies were seldom detected in the sera of KSHV-infected humans. Moreover, these human sera did not potently trigger complement-mediated neutralization, indicating an improvement that immunization can confer. Our study suggests a new antibody-mediated mechanism to control KSHV infection and underscores the benefit of activating the complement system in a future KSHV vaccine.
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Affiliation(s)
- Alex K. Lam
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Romin Roshan
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Wendell Miley
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Nazzarena Labo
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - James Zhen
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Andrew P. Kurland
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Celine Cheng
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Haigen Huang
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Pu-Lin Teng
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Claire Harelson
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Danyang Gong
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Ying K. Tam
- Acuitas Therapeutics, Vancouver, British Columbia, Canada
| | - Caius G. Radu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Marta Epeldegui
- Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Jeffrey R. Johnson
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Z. Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Denise Whitby
- AIDS and Cancer Virus Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, USA
| | - Ting-Ting Wu
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
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6
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A Capsid Structure of Ralstonia solanacearum podoviridae GP4 with a Triangulation Number T = 9. Viruses 2022; 14:v14112431. [PMID: 36366529 PMCID: PMC9698820 DOI: 10.3390/v14112431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
GP4, a new Ralstonia solanacearum phage, is a short-tailed phage. Few structures of Ralstonia solanacearum phages have been resolved to near-atomic resolution until now. Here, we present a 3.7 Å resolution structure of the GP4 head by cryo-electron microscopy (cryo-EM). The GP4 head contains 540 copies of major capsid protein (MCP) gp2 and 540 copies of cement protein (CP) gp1 arranged in an icosahedral shell with a triangulation number T = 9. The structures of gp2 and gp1 show a canonical HK97-like fold and an Ig-like fold, respectively. The trimeric CPs stick on the surface of the head along the quasi-threefold axis of the icosahedron generating a sandwiched three-layer electrostatic complementary potential, thereby enhancing the head stability. The assembly pattern of the GP4 head provides a platform for the further exploration of the interaction between Ralstonia solanacearum and corresponding phages.
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The Contribution of Kaposi's Sarcoma-Associated Herpesvirus ORF7 and Its Zinc-Finger Motif to Viral Genome Cleavage and Capsid Formation. J Virol 2022; 96:e0068422. [PMID: 36073924 PMCID: PMC9517700 DOI: 10.1128/jvi.00684-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During Kaposi’s sarcoma-associated herpesvirus (KSHV) lytic infection, lytic-related proteins are synthesized, viral genomes are replicated as a tandemly repeated form, and subsequently, capsids are assembled. The herpesvirus terminase complex is proposed to package an appropriate genome unit into an immature capsid, by cleavage of terminal repeats (TRs) flanking tandemly linked viral genomes. Although the mechanism of capsid formation in alpha- and betaherpesviruses are well-studied, in KSHV, it remains largely unknown. It has been proposed that KSHV ORF7 is a terminase subunit, and ORF7 harbors a zinc-finger motif, which is conserved among other herpesviral terminases. However, the biological significance of ORF7 is unknown. We previously reported that KSHV ORF17 is essential for the cleavage of inner scaffold proteins in capsid maturation, and ORF17 knockout (KO) induced capsid formation arrest between the procapsid and B-capsid stages. However, it remains unknown if ORF7-mediated viral DNA cleavage occurs before or after ORF17-mediated scaffold collapse. We analyzed the role of ORF7 during capsid formation using ORF7-KO-, ORF7&17-double-KO (DKO)-, and ORF7-zinc-finger motif mutant-KSHVs. We found that ORF7 acted after ORF17 in the capsid formation process, and ORF7-KO-KSHV produced incomplete capsids harboring nonspherical internal structures, which resembled soccer balls. This soccer ball-like capsid was formed after ORF17-mediated B-capsid formation. Moreover, ORF7-KO- and zinc-finger motif KO-KSHV failed to appropriately cleave the TR on replicated genome and had a defect in virion production. Interestingly, ORF17 function was also necessary for TR cleavage. Thus, our data revealed ORF7 contributes to terminase-mediated viral genome cleavage and capsid formation. IMPORTANCE In herpesviral capsid formation, the viral terminase complex cleaves the TR sites on newly synthesized tandemly repeating genomes and inserts an appropriate genomic unit into an immature capsid. Herpes simplex virus 1 (HSV-1) UL28 is a subunit of the terminase complex that cleaves the replicated viral genome. However, the physiological importance of the UL28 homolog, KSHV ORF7, remains poorly understood. Here, using several ORF7-deficient KSHVs, we found that ORF7 acted after ORF17-mediated scaffold collapse in the capsid maturation process. Moreover, ORF7 and its zinc-finger motif were essential for both cleavage of TR sites on the KSHV genome and virus production. ORF7-deficient KSHVs produced incomplete capsids that resembled a soccer ball. To our knowledge, this is the first report showing ORF7-KO-induced soccer ball-like capsids production and ORF7 function in the KSHV capsid assembly process. Our findings provide insights into the role of ORF7 in KSHV capsid formation.
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Sharov TN, Budchenko AA, Viktorov DV, Toporkov AV. The application of mass spectrometry method for the study and identification of medically important viruses (review of literature). Klin Lab Diagn 2022; 67:480-483. [PMID: 36095086 DOI: 10.51620/0869-2084-2022-67-8-480-483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
It is difficult to overestimate the urgency of the problem of well-timed diagnosis of viral infections. According to the WHO, dozens of outbreaks of viral diseases are recorded annually, both in developing and developed countries. Moreover, the seasonal flu virus alone is capable of infecting up to 20% of the population, even in European countries with a high level of medicine. And the annual number of deaths due to viral infections, according to official statistics, exceeds 600 thousand people around the world. That's why the provision of a reliable and fairly rapid diagnosis of viruses, along with subsequent therapy, makes a significant contribution to reducing the incidence of mortality. Despite the fact that PCR-based methods currently remain the most common method for identifying viruses in clinical practice, as recent experience shows, in addition to the already known disadvantages, in the event of large outbreaks, such test systems may simply not be in the required amount. In this regard, it is necessary to supplement and improve the existing tools for identification and research of clinically significant viruses. The MALDI-TOF mass spectrometry method combines a degree of accuracy and versatility, sufficient both for the identification of clinical strains isolated from patients, and for the study of the phenotypic properties of viruses in research laboratories and centers. This article presents and summarizes the main data on the existing or potential application of the method of time-of-flight mass spectrometry with matrix-associated laser desorption / ionization for the identification or study of viruses.
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Affiliation(s)
- T N Sharov
- Federal Government Health Institution «Volgograd Plague Control Research Institute» of the Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare
| | - A A Budchenko
- Federal Government Health Institution «Volgograd Plague Control Research Institute» of the Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare
| | - D V Viktorov
- Federal Government Health Institution «Volgograd Plague Control Research Institute» of the Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare
| | - A V Toporkov
- Federal Government Health Institution «Volgograd Plague Control Research Institute» of the Federal Service for Surveillance in the Sphere of Consumers Rights Protection and Human Welfare
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9
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Wang G, Zha Z, Huang P, Sun H, Huang Y, He M, Chen T, Lin L, Chen Z, Kong Z, Que Y, Li T, Gu Y, Yu H, Zhang J, Zheng Q, Chen Y, Li S, Xia N. Structures of pseudorabies virus capsids. Nat Commun 2022; 13:1533. [PMID: 35318331 PMCID: PMC8940892 DOI: 10.1038/s41467-022-29250-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
Pseudorabies virus (PRV) is a major etiological agent of swine infectious diseases and is responsible for significant economic losses in the swine industry. Recent data points to human viral encephalitis caused by PRV infection, suggesting that PRV may be able to overcome the species barrier to infect humans. To date, there is no available therapeutic for PRV infection. Here, we report the near-atomic structures of the PRV A-capsid and C-capsid, and illustrate the interaction that occurs between these subunits. We show that the C-capsid portal complex is decorated with capsid-associated tegument complexes. The PRV capsid structure is highly reminiscent of other α-herpesviruses, with some additional structural features of β- and γ-herpesviruses. These results illustrate the structure of the PRV capsid and elucidate the underlying assembly mechanism at the molecular level. This knowledge may be useful for the development of oncolytic agents or specific therapeutics against this arm of the herpesvirus family.
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Affiliation(s)
- Guosong Wang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Zhenghui Zha
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Pengfei Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Hui Sun
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Yang Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Maozhou He
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Tian Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Lina Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Zhenqin Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Zhibo Kong
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Yuqiong Que
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Tingting Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Ying Gu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Hai Yu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China.,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China
| | - Qingbing Zheng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China. .,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China.
| | - Yixin Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China. .,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China.
| | - Shaowei Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China. .,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China.
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, School of Life Sciences, Xiamen University, Xiamen, 361102, China. .,National Institute of Diagnostics and Vaccine Development in Infectious Diseases, Xiamen University, Xiamen, 361102, China. .,Research Unit of Frontier Technology of Structural Vaccinology, Chinese Academy of Medical Sciences, Xiamen, 361102, China.
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10
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Prevalence and Risk Factors of Kaposi’s Sarcoma-Associated Herpesvirus Infection among Han and Uygur Populations in Xinjiang, China. CANADIAN JOURNAL OF INFECTIOUS DISEASES AND MEDICAL MICROBIOLOGY 2021; 2021:2555865. [PMID: 35003405 PMCID: PMC8741394 DOI: 10.1155/2021/2555865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/23/2021] [Indexed: 11/18/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), which is endangering human health worldwide, especially in Africa, Europe, the United States, and parts of Asia. The aim of this study was to investigate the prevalence of KSHV in Xinjiang. Three KSHV recombinant proteins (ORF65, ORF73, and K8.1) were used to detect KSHV infection. The serum samples to be tested were detected by an indirect ELISA method. The overall infection rate of KSHV in Xinjiang was 25.60%, with a higher infection rate in the Uygur population of 29.79%. After adjusting for possible confounders, Uygur (OR = 3.95, 95% CI 2.64–6.12, P < 0.001), agriculture and livestock (OR = 1.60, 95% CI 1.20–2.17, P = 0.002), age ≤ 50 years (OR = 1.50, 95% CI 1.13–2.00, P = 0.006), and predominantly meat-based diet (OR = 1.72, 95% CI 1.11–2.78, P = 0.018) were significantly associated with the odds of KSHV seropositivity correlation. Three unique sequences of KSHV were obtained in this study; genotypic analysis showed that the three unique sequences were all subtype A2.
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11
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de Pablo PJ, San Martín C. Seeing and touching adenovirus: complementary approaches for understanding assembly and disassembly of a complex virion. Curr Opin Virol 2021; 52:112-122. [PMID: 34906758 DOI: 10.1016/j.coviro.2021.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 12/24/2022]
Abstract
Understanding adenovirus assembly and disassembly poses many challenges due to the virion complexity. A distinctive feature of adenoviruses is the large amount of virus-encoded proteins packed together with the dsDNA genome. Cryo-electron microscopy (cryo-EM) structures are broadening our understanding of capsid variability along evolution, but little is known about the organization of the non-icosahedral nucleoproteic core and its influence in adenovirus function. Atomic force microscopy (AFM) probes the biomechanics of virus particles, while simultaneously inducing and monitoring their disassembly in real time. Synergistic combination of AFM with EM shows that core proteins play unexpected key roles in maturation and entry, and uncoating dynamics are finely tuned to ensure genome release at the appropriate time and place for successful infection.
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Affiliation(s)
- Pedro J de Pablo
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid and IFIMAC, 28049 Madrid, Spain.
| | - Carmen San Martín
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
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12
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New Look of EBV LMP1 Signaling Landscape. Cancers (Basel) 2021; 13:cancers13215451. [PMID: 34771613 PMCID: PMC8582580 DOI: 10.3390/cancers13215451] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/01/2021] [Accepted: 10/26/2021] [Indexed: 01/18/2023] Open
Abstract
Simple Summary Epstein-Barr Virus (EBV) infection is associated with various lymphomas and carcinomas as well as other diseases in humans. The transmembrane protein LMP1 plays versatile roles in EBV life cycle and pathogenesis, by perturbing, reprograming, and regulating a large range of host cellular mechanisms and functions, which have been increasingly disclosed but not fully understood so far. We summarize recent research progress on LMP1 signaling, including the novel components LIMD1, p62, and LUBAC in LMP1 signalosome and LMP1 novel functions, such as its induction of p62-mediated selective autophagy, regulation of metabolism, induction of extracellular vehicles, and activation of NRF2-mediated antioxidative defense. A comprehensive understanding of LMP1 signal transduction and functions may allow us to leverage these LMP1-regulated cellular mechanisms for clinical purposes. Abstract The Epstein–Barr Virus (EBV) principal oncoprotein Latent Membrane Protein 1 (LMP1) is a member of the Tumor Necrosis Factor Receptor (TNFR) superfamily with constitutive activity. LMP1 shares many features with Pathogen Recognition Receptors (PRRs), including the use of TRAFs, adaptors, and kinase cascades, for signal transduction leading to the activation of NFκB, AP1, and Akt, as well as a subset of IRFs and likely the master antioxidative transcription factor NRF2, which we have gradually added to the list. In recent years, we have discovered the Linear UBiquitin Assembly Complex (LUBAC), the adaptor protein LIMD1, and the ubiquitin sensor and signaling hub p62, as novel components of LMP1 signalosome. Functionally, LMP1 is a pleiotropic factor that reprograms, balances, and perturbs a large spectrum of cellular mechanisms, including the ubiquitin machinery, metabolism, epigenetics, DNA damage response, extracellular vehicles, immune defenses, and telomere elongation, to promote oncogenic transformation, cell proliferation and survival, anchorage-independent cell growth, angiogenesis, and metastasis and invasion, as well as the development of the tumor microenvironment. We have recently shown that LMP1 induces p62-mediated selective autophagy in EBV latency, at least by contributing to the induction of p62 expression, and Reactive Oxygen Species (ROS) production. We have also been collecting evidence supporting the hypothesis that LMP1 activates the Keap1-NRF2 pathway, which serves as the key antioxidative defense mechanism. Last but not least, our preliminary data shows that LMP1 is associated with the deregulation of cGAS-STING DNA sensing pathway in EBV latency. A comprehensive understanding of the LMP1 signaling landscape is essential for identifying potential targets for the development of novel strategies towards targeted therapeutic applications.
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13
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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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14
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Britt HM, Cragnolini T, Thalassinos K. Integration of Mass Spectrometry Data for Structural Biology. Chem Rev 2021; 122:7952-7986. [PMID: 34506113 DOI: 10.1021/acs.chemrev.1c00356] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mass spectrometry (MS) is increasingly being used to probe the structure and dynamics of proteins and the complexes they form with other macromolecules. There are now several specialized MS methods, each with unique sample preparation, data acquisition, and data processing protocols. Collectively, these methods are referred to as structural MS and include cross-linking, hydrogen-deuterium exchange, hydroxyl radical footprinting, native, ion mobility, and top-down MS. Each of these provides a unique type of structural information, ranging from composition and stoichiometry through to residue level proximity and solvent accessibility. Structural MS has proved particularly beneficial in studying protein classes for which analysis by classic structural biology techniques proves challenging such as glycosylated or intrinsically disordered proteins. To capture the structural details for a particular system, especially larger multiprotein complexes, more than one structural MS method with other structural and biophysical techniques is often required. Key to integrating these diverse data are computational strategies and software solutions to facilitate this process. We provide a background to the structural MS methods and briefly summarize other structural methods and how these are combined with MS. We then describe current state of the art approaches for the integration of structural MS data for structural biology. We quantify how often these methods are used together and provide examples where such combinations have been fruitful. To illustrate the power of integrative approaches, we discuss progress in solving the structures of the proteasome and the nuclear pore complex. We also discuss how information from structural MS, particularly pertaining to protein dynamics, is not currently utilized in integrative workflows and how such information can provide a more accurate picture of the systems studied. We conclude by discussing new developments in the MS and computational fields that will further enable in-cell structural studies.
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Affiliation(s)
- Hannah M Britt
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Tristan Cragnolini
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.,Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom
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15
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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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16
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Dzobo K. The Role of Viruses in Carcinogenesis and Molecular Targeting: From Infection to Being a Component of the Tumor Microenvironment. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2021; 25:358-371. [PMID: 34037476 DOI: 10.1089/omi.2021.0052] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
About a tenth of all cancers are caused by viruses or associated with viral infection. Recent global events including the coronavirus disease-2019 (COVID-19) pandemic means that human encounter with viruses is increased. Cancer development in individuals with viral infection can take many years after infection, demonstrating that the involvement of viruses in cancer development is a long and complex process. This complexity emanates from individual genetic heterogeneity and the many steps involved in cancer development owing to viruses. The process of tumorigenesis is driven by the complex interaction between several viral factors and host factors leading to the creation of a tumor microenvironment (TME) that is ideal and promotes tumor formation. Viruses associated with human cancers ensure their survival and proliferation through activation of several cellular processes including inflammation, migration, and invasion, resistance to apoptosis and growth suppressors. In addition, most human oncoviruses evade immune detection and can activate signaling cascades including the PI3K-Akt-mTOR, Notch and Wnt pathways associated with enhanced proliferation and angiogenesis. This expert review examines and synthesizes the multiple biological factors related to oncoviruses, and the signaling cascades activated by these viruses contributing to viral oncogenesis. In particular, I examine and review the Epstein-Barr virus, human papillomaviruses, and Kaposi's sarcoma herpes virus in a context of cancer pathogenesis. I conclude with a future outlook on therapeutic targeting of the viruses and their associated oncogenic pathways within the TME. These anticancer strategies can be in the form of, but not limited to, antibodies and inhibitors.
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Affiliation(s)
- Kevin Dzobo
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Cape Town Component, Cape Town, South Africa.,Division of Medical Biochemistry and Institute of Infectious Disease and Molecular Medicine, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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17
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Costantini LM, Damania B. DNA Viruses. Virology 2021. [DOI: 10.1002/9781119818526.ch1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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The Portal Vertex of KSHV Promotes Docking of Capsids at the Nuclear Pores. Viruses 2021; 13:v13040597. [PMID: 33807444 PMCID: PMC8065994 DOI: 10.3390/v13040597] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is a cancer-related herpesvirus. Like other herpesviruses, the KSHV icosahedral capsid includes a portal vertex, composed of 12 protein subunits encoded by open reading frame (ORF) 43, which enables packaging and release of the viral genome into the nucleus through the nuclear pore complex (NPC). Capsid vertex-specific component (CVSC) tegument proteins, which directly mediate docking at the NPCs, are organized on the capsid vertices and are enriched on the portal vertex. Whether and how the portal vertex is selected for docking at the NPC is unknown. Here, we investigated the docking of incoming ORF43-null KSHV capsids at the NPCs, and describe a significantly lower fraction of capsids attached to the nuclear envelope compared to wild-type (WT) capsids. Like WT capsids, nuclear envelope-associated ORF43-null capsids co-localized with different nucleoporins (Nups) and did not detach upon salt treatment. Inhibition of nuclear export did not alter WT capsid docking. As ORF43-null capsids exhibit lower extent of association with the NPCs, we conclude that although not essential, the portal has a role in mediating the interaction of the CVSC proteins with Nups, and suggest a model whereby WT capsids can dock at the nuclear envelope through a non-portal penton vertex, resulting in an infection 'dead end'.
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19
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Tsurumi S, Watanabe T, Iwaisako Y, Suzuki Y, Nakano T, Fujimuro M. Kaposi's sarcoma-associated herpesvirus ORF17 plays a key role in capsid maturation. Virology 2021; 558:76-85. [PMID: 33735753 DOI: 10.1016/j.virol.2021.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 02/12/2021] [Accepted: 02/19/2021] [Indexed: 01/04/2023]
Abstract
Kaposi's sarcoma-associated herpesvirus is a human rhadinovirus of the gammaherpesvirus sub-family. Although herpesviruses are well-studied models of capsid formation and its processes, those of KSHV remain unknown. KSHV ORF17 encoding the viral protease precursor (ORF17-prePR) is thought to contribute to capsid formation; however, functional information is largely unknown. Here, we evaluated the role of ORF17 during capsid formation by generating ORF17-deficient and ORF17 protease-dead KSHV. Both mutants showed a decrease in viral production but not DNA replication. ORF17 R-mut, with a point-mutation at the restriction or release site (R-site) by which ORF17-prePR can be functionally cleaved into a protease (ORF17-PR) and an assembly region (ORF17-pAP/-AP), failed to play a role in viral production. Furthermore, wild type KSHV produced a mature capsid, whereas ORF17-deficient and protease-dead KSHV produced a B-capsid, (i.e., a closed body possessing a circular inner structure). Therefore, ORF17 and its protease function are essential for appropriate capsid maturation.
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Affiliation(s)
- Sayaka Tsurumi
- Department of Cell Biology, Kyoto Pharmaceutical University, 1 Misasagi-Shichono, Yamashina, Kyoto, 607-8412, Japan
| | - Tadashi Watanabe
- Department of Cell Biology, Kyoto Pharmaceutical University, 1 Misasagi-Shichono, Yamashina, Kyoto, 607-8412, Japan; Department of Virology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Nakagami, Okinawa, 903-0215, Japan
| | - Yuki Iwaisako
- Department of Cell Biology, Kyoto Pharmaceutical University, 1 Misasagi-Shichono, Yamashina, Kyoto, 607-8412, Japan
| | - Youichi Suzuki
- Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Takashi Nakano
- Department of Microbiology and Infection Control, Osaka Medical College, 2-7 Daigaku-machi, Takatsuki, Osaka, 569-8686, Japan
| | - Masahiro Fujimuro
- Department of Cell Biology, Kyoto Pharmaceutical University, 1 Misasagi-Shichono, Yamashina, Kyoto, 607-8412, Japan.
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20
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Muller C, Alain S, Baumert TF, Ligat G, Hantz S. Structures and Divergent Mechanisms in Capsid Maturation and Stabilization Following Genome Packaging of Human Cytomegalovirus and Herpesviruses. Life (Basel) 2021; 11:life11020150. [PMID: 33669389 PMCID: PMC7920273 DOI: 10.3390/life11020150] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/11/2021] [Accepted: 02/12/2021] [Indexed: 01/13/2023] Open
Abstract
Herpesviruses are the causative agents of several diseases. Infections are generally mild or asymptomatic in immunocompetent individuals. In contrast, herpesvirus infections continue to contribute to significant morbidity and mortality in immunocompromised patients. Few drugs are available for the treatment of human herpesvirus infections, mainly targeting the viral DNA polymerase. Moreover, no successful therapeutic options are available for the Epstein–Barr virus or human herpesvirus 8. Most licensed drugs share the same mechanism of action of targeting the viral polymerase and thus blocking DNA polymerization. Resistances to antiviral drugs have been observed for human cytomegalovirus, herpes simplex virus and varicella-zoster virus. A new terminase inhibitor, letermovir, recently proved effective against human cytomegalovirus. However, the letermovir has no significant activity against other herpesviruses. New antivirals targeting other replication steps, such as capsid maturation or DNA packaging, and inducing fewer adverse effects are therefore needed. Targeting capsid assembly or DNA packaging provides additional options for the development of new drugs. In this review, we summarize recent findings on capsid assembly and DNA packaging. We also described what is known about the structure and function of capsid and terminase proteins to identify novels targets for the development of new therapeutic options.
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Affiliation(s)
- Clotilde Muller
- INSERM, CHU Limoges, University of Limoges, RESINFIT, U1092, 87000 Limoges, France; (C.M.); (S.A.)
| | - Sophie Alain
- INSERM, CHU Limoges, University of Limoges, RESINFIT, U1092, 87000 Limoges, France; (C.M.); (S.A.)
- CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRCHV), 87000 Limoges, France
| | - Thomas F. Baumert
- Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, 67000 Strasbourg, France;
- Institut Hospitalo-Universitaire, Pôle Hépato-Digestif, Nouvel Hôpital Civil, 67000 Strasbourg, France
| | - Gaëtan Ligat
- Institut de Recherche sur les Maladies Virales et Hépatiques, Université de Strasbourg, 67000 Strasbourg, France;
- Correspondence: (G.L.); (S.H.)
| | - Sébastien Hantz
- INSERM, CHU Limoges, University of Limoges, RESINFIT, U1092, 87000 Limoges, France; (C.M.); (S.A.)
- CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRCHV), 87000 Limoges, France
- Correspondence: (G.L.); (S.H.)
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21
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Cryo-EM structure of the varicella-zoster virus A-capsid. Nat Commun 2020; 11:4795. [PMID: 32963252 PMCID: PMC7508878 DOI: 10.1038/s41467-020-18537-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 08/26/2020] [Indexed: 12/15/2022] Open
Abstract
Varicella-zoster virus (VZV), a member of the Alphaherpesvirinae subfamily, causes severe diseases in humans of all ages. The viral capsids play critical roles in herpesvirus infection, making them potential antiviral targets. Here, we present the 3.7-Å-resolution structure of the VZV A-capsid and define the molecular determinants underpinning the assembly of this complicated viral machinery. Overall, the VZV capsid has a similar architecture to that of other known herpesviruses. The major capsid protein (MCP) assembles into pentons and hexons, forming extensive intra- and inter-capsomer interaction networks that are further secured by the small capsid protein (SCP) and the heterotriplex. The structure reveals a pocket beneath the floor of MCP that could potentially be targeted by antiviral inhibitors. In addition, we identified two alphaherpesvirus-specific structural features in SCP and Tri1 proteins. These observations highlight the divergence of different herpesviruses and provide an important basis for developing antiviral drugs. Varicella-zoster virus (VZV) is the causative agent of chickenpox and herpes zoster (shingles). Cryo-EM structure of VZV capsid provides insights into the capsid assembly and reveals a pocket that could potentially be targeted by antiviral drugs.
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22
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Near-atomic cryo-electron microscopy structures of varicella-zoster virus capsids. Nat Microbiol 2020; 5:1542-1552. [PMID: 32895526 DOI: 10.1038/s41564-020-0785-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 08/03/2020] [Indexed: 12/18/2022]
Abstract
Varicella-zoster virus (VZV) is a medically important human herpesvirus that causes chickenpox and shingles, but its cell-associated nature has hindered structure studies. Here we report the cryo-electron microscopy structures of purified VZV A-capsid and C-capsid, as well as of the DNA-containing capsid inside the virion. Atomic models derived from these structures show that, despite enclosing a genome that is substantially smaller than those of other human herpesviruses, VZV has a similarly sized capsid, consisting of 955 major capsid protein (MCP), 900 small capsid protein (SCP), 640 triplex dimer (Tri2) and 320 triplex monomer (Tri1) subunits. The VZV capsid has high thermal stability, although with relatively fewer intra- and inter-capsid protein interactions and less stably associated tegument proteins compared with other human herpesviruses. Analysis with antibodies targeting the N and C termini of the VZV SCP indicates that the hexon-capping SCP-the largest among human herpesviruses-uses its N-terminal half to bridge hexon MCP subunits and possesses a C-terminal flexible half emanating from the inner rim of the upper hexon channel into the tegument layer. Correlation of these structural features and functional observations provide insights into VZV assembly and pathogenesis and should help efforts to engineer gene delivery and anticancer vectors based on the currently available VZV vaccine.
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23
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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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24
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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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25
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Li Z, Yu X. Progress towards revealing the mechanism of herpesvirus capsid maturation and genome packaging. Protein Cell 2020; 11:316-317. [PMID: 32270449 PMCID: PMC7196561 DOI: 10.1007/s13238-020-00716-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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
| | - 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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26
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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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27
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Principles for enhancing virus capsid capacity and stability from a thermophilic virus capsid structure. Nat Commun 2019; 10:4471. [PMID: 31578335 PMCID: PMC6775164 DOI: 10.1038/s41467-019-12341-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 08/31/2019] [Indexed: 12/21/2022] Open
Abstract
The capsids of double-stranded DNA viruses protect the viral genome from the harsh extracellular environment, while maintaining stability against the high internal pressure of packaged DNA. To elucidate how capsids maintain stability in an extreme environment, we use cryoelectron microscopy to determine the capsid structure of thermostable phage P74-26 to 2.8-Å resolution. We find P74-26 capsids exhibit an overall architecture very similar to those of other tailed bacteriophages, allowing us to directly compare structures to derive the structural basis for enhanced stability. Our structure reveals lasso-like interactions that appear to function like catch bonds. This architecture allows the capsid to expand during genome packaging, yet maintain structural stability. The P74-26 capsid has T = 7 geometry despite being twice as large as mesophilic homologs. Capsid capacity is increased with a larger, flatter major capsid protein. Given these results, we predict decreased icosahedral complexity (i.e. T ≤ 7) leads to a more stable capsid assembly. Viral capsids need to protect the genome against harsh environmental conditions and cope with high internal pressure from the packaged genome. Here, the authors determine the structure of the thermostable phage P74-26 capsid at 2.8-Å resolution and identify features underlying enhanced capsid capacity and structural stability.
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28
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Gong D, Dai X, Jih J, Liu YT, Bi GQ, Sun R, Zhou ZH. DNA-Packing Portal and Capsid-Associated Tegument Complexes in the Tumor Herpesvirus KSHV. Cell 2019; 178:1329-1343.e12. [PMID: 31447177 PMCID: PMC6753055 DOI: 10.1016/j.cell.2019.07.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/16/2019] [Accepted: 07/17/2019] [Indexed: 01/07/2023]
Abstract
Assembly of Kaposi's sarcoma-associated herpesvirus (KSHV) begins at a bacteriophage-like portal complex that nucleates formation of an icosahedral capsid with capsid-associated tegument complexes (CATCs) and facilitates translocation of an ∼150-kb dsDNA genome, followed by acquisition of a pleomorphic tegument and envelope. Because of deviation from icosahedral symmetry, KSHV portal and tegument structures have largely been obscured in previous studies. Using symmetry-relaxed cryo-EM, we determined the in situ structure of the KSHV portal and its interactions with surrounding capsid proteins, CATCs, and the terminal end of KSHV's dsDNA genome. Our atomic models of the portal and capsid/CATC, together with visualization of CATCs' variable occupancy and alternate orientation of CATC-interacting vertex triplexes, suggest a mechanism whereby the portal orchestrates procapsid formation and asymmetric long-range determination of CATC attachment during DNA packaging prior to pleomorphic tegumentation/envelopment. Structure-based mutageneses confirm that a triplex deep binding groove for CATCs is a hotspot that holds promise for antiviral development.
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Affiliation(s)
- Danyang Gong
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Xinghong Dai
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jonathan Jih
- California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Yun-Tao Liu
- California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, 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 (USTC), Hefei, Anhui 230026, 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
| | - Ren Sun
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute (CNSI), University of California, Los Angeles, Los Angeles, CA 90095, USA.
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29
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Liu W, Dai X, Jih J, Chan K, Trang P, Yu X, Balogun R, Mei Y, Liu F, Zhou ZH. Atomic structures and deletion mutant reveal different capsid-binding patterns and functional significance of tegument protein pp150 in murine and human cytomegaloviruses with implications for therapeutic development. PLoS Pathog 2019; 15:e1007615. [PMID: 30779794 PMCID: PMC6396938 DOI: 10.1371/journal.ppat.1007615] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 03/01/2019] [Accepted: 02/01/2019] [Indexed: 12/12/2022] Open
Abstract
Cytomegalovirus (CMV) infection causes birth defects and life-threatening complications in immunosuppressed patients. Lack of vaccine and need for more effective drugs have driven widespread ongoing therapeutic development efforts against human CMV (HCMV), mostly using murine CMV (MCMV) as the model system for preclinical animal tests. The recent publication (Yu et al., 2017, DOI: 10.1126/science.aam6892) of an atomic model for HCMV capsid with associated tegument protein pp150 has infused impetus for rational design of novel vaccines and drugs, but the absence of high-resolution structural data on MCMV remains a significant knowledge gap in such development efforts. Here, by cryoEM with sub-particle reconstruction method, we have obtained the first atomic structure of MCMV capsid with associated pp150. Surprisingly, the capsid-binding patterns of pp150 differ between HCMV and MCMV despite their highly similar capsid structures. In MCMV, pp150 is absent on triplex Tc and exists as a “Λ”-shaped dimer on other triplexes, leading to only 260 groups of two pp150 subunits per capsid in contrast to 320 groups of three pp150 subunits each in a “Δ”-shaped fortifying configuration. Many more amino acids contribute to pp150-pp150 interactions in MCMV than in HCMV, making MCMV pp150 dimer inflexible thus incompatible to instigate triplex Tc-binding as observed in HCMV. While pp150 is essential in HCMV, our pp150-deletion mutant of MCMV remained viable though with attenuated infectivity and exhibiting defects in retaining viral genome. These results thus invalidate targeting pp150, but lend support to targeting capsid proteins, when using MCMV as a model for HCMV pathogenesis and therapeutic studies. Cytomegalovirus (CMV) infection is a leading viral cause of birth defects and could be deadly to AIDS patients and organ transplant recipients. Absence of effective vaccines and potent drugs against human CMV (HCMV) infections has motivated animal-based studies, mostly based on the mouse model with murine CMV (MCMV), both for understanding pathogenesis of CMV infections and for developing therapeutic strategies. Distinct from other medically important herpesviruses (those responsible for cold sores, genital herpes, shingles and several human cancers), CMV contains an abundant phosphoprotein, pp150, which is a structurally, immunogenically, and regulatorily important tegument protein and a potential drug target. Here, we used cryoEM with localized reconstruction method to obtain the first atomic structure of MCMV. The structure reveals that the organization patterns of the capsid-associated tegument protein pp150 are different in MCMV and HCMV, despite their highly similar capsid structures. We also show that deleting pp150 did not eliminate MCMV infection in contrast to pp150’s essential role in HCMV infections. Our results have significant implication to the current practice of using mouse infected with MCMV for HCMV therapeutic development.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Precision Spectroscopy, School of Physics and Material Science, East China Normal University, Shanghai, China
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Xinghong Dai
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Jonathan Jih
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Karen Chan
- School of Public Health, University of California at Berkeley, Berkeley, California, United States of America
| | - Phong Trang
- Program in Comparative Biochemistry, University of California at Berkeley, Berkeley, California, United States of America
- Department of Biotechnology, College of Life Science and Technology, Jinan University, Guangzhou, Guangdong, China
| | - Xuekui Yu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Rilwan Balogun
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
| | - Ye Mei
- State Key Laboratory of Precision Spectroscopy, School of Physics and Material Science, East China Normal University, Shanghai, China
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai, China
| | - Fenyong Liu
- School of Public Health, University of California at Berkeley, Berkeley, California, United States of America
- Program in Comparative Biochemistry, University of California at Berkeley, Berkeley, California, United States of America
| | - Z. Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, United States of America
- California NanoSystems Institute, UCLA, Los Angeles, California, United States of America
- * E-mail:
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30
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Structure of the herpes simplex virus type 2 C-capsid with capsid-vertex-specific component. Nat Commun 2018; 9:3668. [PMID: 30201968 PMCID: PMC6131487 DOI: 10.1038/s41467-018-06078-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 08/11/2018] [Indexed: 11/19/2022] Open
Abstract
Herpes simplex viruses (HSVs) cause human oral and genital ulcer diseases. Patients with HSV-2 have a higher risk of acquiring a human immunodeficiency virus infection. HSV-2 is a member of the α-herpesvirinae subfamily that together with the β- and γ-herpesvirinae subfamilies forms the Herpesviridae family. Here, we report the cryo-electron microscopy structure of the HSV-2 C-capsid with capsid-vertex-specific component (CVSC) that was determined at 3.75 Å using a block-based reconstruction strategy. We present atomic models of multiple conformers for the capsid proteins (VP5, VP23, VP19C, and VP26) and CVSC. Comparison of the HSV-2 homologs yields information about structural similarities and differences between the three herpesviruses sub-families and we identify α-herpesvirus-specific structural features. The hetero-pentameric CVSC, consisting of a UL17 monomer, a UL25 dimer and a UL36 dimer, is bound tightly by a five-helix bundle that forms extensive networks of subunit contacts with surrounding capsid proteins, which reinforce capsid stability. Herpes simplex virus type-2 (HSV-2) belongs to the α-herpesvirinae subfamily and is a sexually transmitted virus that causes genital ulcer disease. Here the authors present the 3.75 Å cryo-EM structure of the HSV-2 C-capsid with capsid-vertex-specific component and describe α-herpesvirus-specific structural features.
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31
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The Apical Region of the Herpes Simplex Virus Major Capsid Protein Promotes Capsid Maturation. J Virol 2018; 92:JVI.00821-18. [PMID: 29976665 DOI: 10.1128/jvi.00821-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/27/2018] [Indexed: 01/12/2023] Open
Abstract
The herpesvirus capsid assembles in the nucleus as an immature procapsid precursor built around viral scaffold proteins. The event that initiates procapsid maturation is unknown, but it is dependent upon activation of the VP24 internal protease. Scaffold cleavage triggers angularization of the shell and its decoration with the VP26 and pUL25 capsid-surface proteins. In both the procapsid and mature angularized capsid, the apical region of the major capsid protein (VP5) is surface exposed. We investigated whether the VP5 apical region contributes to intracellular transport dynamics following entry into primary sensory neurons and also tested the hypothesis that conserved negatively charged amino acids in the apical region contribute to VP26 acquisition. To our surprise, neither hypothesis proved true. Instead, mutation of glutamic acid residues in the apical region delayed viral propagation and induced focal capsid accumulations in nuclei. Examination of capsid morphogenesis based on epitope unmasking, capsid composition, and ultrastructural analysis indicated that these clusters consisted of procapsids. The results demonstrate that, in addition to established events that occur inside the capsid, the exterior capsid shell promotes capsid morphogenesis and maturation.IMPORTANCE Herpesviruses assemble capsids and encapsidate their genomes by a process that is unlike those of other mammalian viruses but is similar to those of some bacteriophage. Many important aspects of herpesvirus morphogenesis remain enigmatic, including how the capsid shell matures into a stable angularized configuration. Capsid maturation is triggered by activation of a protease that cleaves an internal protein scaffold. We report on the fortuitous discovery that a region of the major capsid protein that is exposed on the outer surface of the capsid also contributes to capsid maturation, demonstrating that the morphogenesis of the capsid shell from its procapsid precursor to the mature angularized form is dependent upon internal and external components of the megastructure.
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32
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Stass R, Ilca SL, Huiskonen JT. Beyond structures of highly symmetric purified viral capsids by cryo-EM. Curr Opin Struct Biol 2018; 52:25-31. [PMID: 30096461 DOI: 10.1016/j.sbi.2018.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/24/2018] [Accepted: 07/24/2018] [Indexed: 10/28/2022]
Abstract
Cryogenic transmission electron microscopy (cryo-EM) is widely used to determine high-resolution structures of symmetric virus capsids. The method holds promise for extending studies beyond purified capsids and their symmetric protein shells. The non-symmetric genome component has been addressed in dsRNA cypoviruses and ssRNA bacteriophages Qβ and MS2. The structure of human herpes simplex virus type 1 capsids has been determined within intact virions to resolve capsid-tegument interactions. Electron tomography under cryogenic conditions (cryo-ET), has allowed resolving an early membrane fusion intermediate of Rift Valley fever virus. Antibody-affinity based sample grids allow capturing of virions directly from cell cultures or even clinical samples. These and other emerging methods will support studies to address viral entry, assembly and neutralization processes at increasingly high resolutions and native conditions.
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Affiliation(s)
- Robert Stass
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, OX3 7BN Oxford, UK
| | - Serban L Ilca
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, OX3 7BN Oxford, UK
| | - Juha T Huiskonen
- Division of Structural Biology, Wellcome Centre for Human Genetics, Roosevelt Drive, University of Oxford, OX3 7BN Oxford, UK; Helsinki Institute of Life Science HiLIFE and Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, Viikinkaari 1, University of Helsinki, 00014 Helsinki, Finland.
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33
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Visualization of molecular biology: The LANA tether. Proc Natl Acad Sci U S A 2018; 115:4816-4818. [DOI: 10.1073/pnas.1804797115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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34
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Affiliation(s)
- Ekaterina E Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA.
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35
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Dai X, Zhou ZH. Structure of the herpes simplex virus 1 capsid with associated tegument protein complexes. Science 2018; 360:360/6384/eaao7298. [PMID: 29622628 DOI: 10.1126/science.aao7298] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 02/23/2018] [Indexed: 12/25/2022]
Abstract
Herpes simplex viruses (HSVs) rely on capsid-associated tegument complex (CATC) for long-range axonal transport of their genome-containing capsids between sites of infection and neuronal cell bodies. Here we report cryo-electron microscopy structures of the HSV-1 capsid with CATC up to 3.5-angstrom resolution and atomic models of multiple conformers of capsid proteins VP5, VP19c, VP23, and VP26 and tegument proteins pUL17, pUL25, and pUL36. Crowning every capsid vertex are five copies of heteropentameric CATC, each containing a pUL17 monomer supporting the coiled-coil helix bundle of a pUL25 dimer and a pUL36 dimer, thus positioning their flexible domains for potential involvement in nuclear capsid egress and axonal capsid transport. Notwithstanding newly discovered fold conservation between triplex proteins and bacteriophage λ protein gpD and the previously recognized bacteriophage HK97 gp5-like fold in VP5, HSV-1 capsid proteins exhibit extraordinary diversity in forms of domain insertion and conformational polymorphism, not only for interactions with tegument proteins but also for encapsulation of large genomes.
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Affiliation(s)
- Xinghong Dai
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA.,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA. .,California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
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36
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Taylor LF, Yuan Y. Structure of Herpesvirus Capsid Sheds Light on Drug Discovery. Trends Microbiol 2018; 26:391-392. [PMID: 29602619 DOI: 10.1016/j.tim.2018.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 03/13/2018] [Indexed: 11/18/2022]
Abstract
The atomic resolution structure of Kaposi's sarcoma-associated herpesvirus (KSHV) capsid reveals that protein-protein interfaces (PPIs) are essential for its structural stability. This structural information guided a mutagenesis study that identified novel drug targets interrupting PPIs essential for capsid assembly.
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Affiliation(s)
- Louis F Taylor
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104, USA
| | - Yan Yuan
- Department of Microbiology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA 19104, USA.
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