1
|
Stevens A, Cruz-Cosme R, Armstrong N, Tang Q, Zhou ZH. Structure-guided mutagenesis targeting interactions between pp150 tegument protein and small capsid protein identify five lethal and two live-attenuated HCMV mutants. Virology 2024; 596:110115. [PMID: 38805802 DOI: 10.1016/j.virol.2024.110115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 05/01/2024] [Accepted: 05/14/2024] [Indexed: 05/30/2024]
Abstract
Human cytomegalovirus (HCMV) replication relies on a nucleocapsid coat of the 150 kDa, subfamily-specific tegument phosphoprotein (pp150) to regulate cytoplasmic virion maturation. While recent structural studies revealed pp150-capsid interactions, the role of specific amino-acids involved in these interactions have not been established experimentally. In this study, pp150 and the small capsid protein (SCP), one of pp150's binding partners found atop the major capsid protein (MCP), were subjected to mutational and structural analyses. Mutations to clusters of polar or hydrophobic residues along the pp150-SCP interface abolished viral replication, with no replication detected in mutant virus-infected cells. Notably, a single amino acid mutation (pp150 K255E) at the pp150-MCP interface significantly attenuated viral replication, unlike in pp150-deletion mutants where capsids degraded outside host nuclei. These functionally significant mutations targeting pp150-capsid interactions, particularly the pp150 K255E replication-attenuated mutant, can be explored to overcome the historical challenges of developing effective antivirals and vaccines against HCMV infection.
Collapse
Affiliation(s)
- Alexander Stevens
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA
| | - Ruth Cruz-Cosme
- Department of Microbiology, Howard University College of Medicine, Washington, DC 20059, USA
| | - Najealicka Armstrong
- Department of Microbiology, Howard University College of Medicine, Washington, DC 20059, USA
| | - Qiyi Tang
- Department of Microbiology, Howard University College of Medicine, Washington, DC 20059, USA
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA 90095, USA.
| |
Collapse
|
2
|
Yan T, Pang X, Liang B, Meng Q, Wei H, Li W, Liu D, Hu Y. Comprehensive bioinformatics analysis of human cytomegalovirus pathway genes in pan-cancer. Hum Genomics 2024; 18:65. [PMID: 38886862 PMCID: PMC11181644 DOI: 10.1186/s40246-024-00633-5] [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: 12/23/2023] [Accepted: 06/05/2024] [Indexed: 06/20/2024] Open
Abstract
BACKGROUND Human cytomegalovirus (HCMV) is a herpesvirus that can infect various cell types and modulate host gene expression and immune response. It has been associated with the pathogenesis of various cancers, but its molecular mechanisms remain elusive. METHODS We comprehensively analyzed the expression of HCMV pathway genes across 26 cancer types using the Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) databases. We also used bioinformatics tools to study immune invasion and tumor microenvironment in pan-cancer. Cox regression and machine learning were used to analyze prognostic genes and their relationship with drug sensitivity. RESULTS We found that HCMV pathway genes are widely expressed in various cancers. Immune infiltration and the tumor microenvironment revealed that HCMV is involved in complex immune processes. We obtained prognostic genes for 25 cancers and significantly found 23 key genes in the HCMV pathway, which are significantly enriched in cellular chemotaxis and synaptic function and may be involved in disease progression. Notably, CaM family genes were up-regulated and AC family genes were down-regulated in most tumors. These hub genes correlate with sensitivity or resistance to various drugs, suggesting their potential as therapeutic targets. CONCLUSIONS Our study has revealed the role of the HCMV pathway in various cancers and provided insights into its molecular mechanism and therapeutic significance. It is worth noting that the key genes of the HCMV pathway may open up new doors for cancer prevention and treatment.
Collapse
Affiliation(s)
- Tengyue Yan
- Collaborative Innovation Centre of Regenerative Medicine and Medical Bioresource Development and Application Co-constructed by the Province and Ministry, Guangxi Medical University, Nanning, Guangxi, 530021, China
| | - Xianwu Pang
- Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning, 530028, China
| | - Boying Liang
- Department of Immunology, School of Basic Medical Sciences, Guangxi Medical University, Nanning, China
| | - Qiuxia Meng
- School of Information and Managent, Guangxi Medical University, Nanning, China
| | - Huilin Wei
- School of Institute of Life Sciences, Guangxi Medical University, Nanning, China
| | - Wen Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Guangxi Medical University, Nanning, China
| | - Dahai Liu
- School of Medicine, Foshan University, Foshan, Guangdong, 528000, People's Republic of China.
| | - Yanling Hu
- Collaborative Innovation Centre of Regenerative Medicine and Medical Bioresource Development and Application Co-constructed by the Province and Ministry, Guangxi Medical University, Nanning, Guangxi, 530021, China.
- School of Institute of Life Sciences, Guangxi Medical University, Nanning, China.
| |
Collapse
|
3
|
Beeton K, Mitra D, Akinleye AA, Howell JA, Yu CS, Bidwell GL, Tandon R. An Elastin-like Polypeptide-fusion peptide targeting capsid-tegument interface as an antiviral against cytomegalovirus infection. Sci Rep 2024; 14:10253. [PMID: 38704431 PMCID: PMC11069587 DOI: 10.1038/s41598-024-60691-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 04/26/2024] [Indexed: 05/06/2024] Open
Abstract
The tegument protein pp150 of Human Cytomegalovirus (HCMV) is known to be essential for the final stages of virus maturation and mediates its functions by interacting with capsid proteins. Our laboratory has previously identified the critical regions in pp150 important for pp150-capsid interactions and designed peptides similar in sequence to these regions, with a goal to competitively inhibit capsid maturation. Treatment with a specific peptide (PepCR2 or P10) targeted to pp150 conserved region 2 led to a significant reduction in murine CMV (MCMV) growth in cell culture, paving the way for in vivo testing in a mouse model of CMV infection. However, the general pharmacokinetic parameters of peptides, including rapid degradation and limited tissue and cell membrane permeability, pose a challenge to their successful use in vivo. Therefore, we designed a biopolymer-stabilized elastin-like polypeptide (ELP) fusion construct (ELP-P10) to enhance the bioavailability of P10. Antiviral efficacy and cytotoxic effects of ELP-P10 were studied in cell culture, and pharmacokinetics, biodistribution, and antiviral efficacy were studied in a mouse model of CMV infection. ELP-P10 maintained significant antiviral activity in cell culture, and this conjugation significantly enhanced P10 bioavailability in mouse tissues. The fluorescently labeled ELP-P10 accumulated to higher levels in mouse liver and kidneys as compared to the unconjugated P10. Moreover, viral titers from vital organs of MCMV-infected mice indicated a significant reduction of virus load upon ELP-P10 treatment. Therefore, ELP-P10 has the potential to be developed into an effective antiviral against CMV infection.
Collapse
Affiliation(s)
- Komal Beeton
- Department of Cell and Molecular Biology, Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Dipanwita Mitra
- Department of Cell and Molecular Biology, Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Adesanya A Akinleye
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - John A Howell
- Department of Neurology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Christian S Yu
- Department of Cell and Molecular Biology, Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Gene L Bidwell
- Department of Cell and Molecular Biology, Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
- Department of Neurology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ritesh Tandon
- Department of Cell and Molecular Biology, Center for Immunology and Microbial Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
- Office of Research Infrastructure Programs, National Institute of Health, 6701 Democracy Blvd., Bethesda, MD, 20892, USA.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Chen M, Sahoo B, Mou Z, Song X, Tsai T, Dai X. Genome organization in double-stranded DNA viruses observed by cryoET. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.15.571939. [PMID: 38168199 PMCID: PMC10760162 DOI: 10.1101/2023.12.15.571939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Double-stranded DNA (dsDNA) viruses package their genetic material into protein cages with diameters usually a few hundred times smaller than the length of their genome. Compressing the relatively stiff and highly negatively charged dsDNA into a small volume is energetically costly and mechanistically enigmatic. Multiple models of dsDNA packaging have been proposed based on various experimental evidence and simulation methods, but direct observation of any viral genome organization is lacking. Here, using cryoET and an improved data processing scheme that utilizes information from the encaging protein shell, we present 3D views of dsDNA genome inside individual viral particles at resolution that densities of neighboring DNA duplexes are readily separable. These cryoET observations reveal a "rod-and-coil" fold of the dsDNA that is conserved among herpes simplex virus type 1 (HSV-1) with a spherical capsid, bacteriophage T4 with a prolate capsid, and bacteriophage T7 with a proteinaceous core inside the capsid. Finally, inspired by the genome arrangement in partially packaged T4 particles, we propose a mechanism for the genome packaging process in dsDNA viruses.
Collapse
Affiliation(s)
- Muyuan Chen
- Division of CryoEM and Bioimaging, SSRL, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - Bibekananda Sahoo
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Zongjun Mou
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xiyong Song
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Tiffany Tsai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Xinghong Dai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
- Lead contact
| |
Collapse
|
6
|
Zhu D, Cao D, Zhang X. Virus structures revealed by advanced cryoelectron microscopy methods. Structure 2023; 31:1348-1359. [PMID: 37797619 DOI: 10.1016/j.str.2023.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/25/2023] [Accepted: 09/11/2023] [Indexed: 10/07/2023]
Abstract
Before the resolution revolution, cryoelectron microscopy (cryo-EM) single-particle analysis (SPA) already achieved resolutions beyond 4 Å for certain icosahedral viruses, enabling ab initio atomic model building of these viruses. As the only samples that achieved such high resolution at that time, cryo-EM method development was closely intertwined with the improvement of reconstructions of symmetrical viruses. Viral morphology exhibits significant diversity, ranging from small to large, uniform to non-uniform, and from containing single symmetry to multiple symmetries. Furthermore, viruses undergo conformational changes during their life cycle. Several methods, such as asymmetric reconstruction, Ewald sphere correction, cryoelectron tomography (cryo-ET), and sub-tomogram averaging (STA), have been developed and applied to determine virus structures in vivo and in vitro. This review outlines current advanced cryo-EM methods for high-resolution structure determination of viruses and summarizes accomplishments obtained with these approaches. Moreover, persisting challenges in comprehending virus structures are discussed and we propose potential solutions.
Collapse
Affiliation(s)
- Dongjie Zhu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Duanfang Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| |
Collapse
|
7
|
Singh S, Maheshwari A, Boppana S. CMV-induced Hearing Loss. NEWBORN (CLARKSVILLE, MD.) 2023; 2:249-262. [PMID: 38348106 PMCID: PMC10860330 DOI: 10.5005/jp-journals-11002-0081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
Congenital cytomegalovirus (cCMV) infection is the most common fetal viral infection and contributes to about 25% of childhood hearing loss by the age of 4 years. It is the leading nongenetic cause of sensorineural hearing loss (SNHL). Infants born to seroimmune mothers are not completely protected from SNHL, although the severity of their hearing loss may be milder than that seen in those whose mothers had a primary infection. Both direct cytopathic effects and localized inflammatory responses contribute to the pathogenesis of cytomegalovirus (CMV)-induced hearing loss. Hearing loss may be delayed onset, progressive or fluctuating in nature, and therefore, a significant proportion will be missed by universal newborn hearing screening (NHS) and warrants close monitoring of hearing function at least until 5-6 years of age. A multidisciplinary approach is required for the management of hearing loss. These children may need assistive hearing devices or cochlear implantation depending on the severity of their hearing loss. In addition, early intervention services such as speech or occupational therapy could help better communication, language, and social skill outcomes. Preventive measures to decrease intrauterine CMV transmission that have been evaluated include personal protective measures, passive immunoprophylaxis and valacyclovir treatment during pregnancy in mothers with primary CMV infection. Several vaccine candidates are currently in testing and one candidate vaccine in phase 3 trials. Until a CMV vaccine becomes available, behavioral and educational interventions may be the most effective strategy to prevent maternal CMV infection.
Collapse
Affiliation(s)
- Srijan Singh
- Department of Neonatology, Kailash Hospital, Noida, Uttar Pradesh, India
- Global Newborn Society (https://www.globalnewbornsociety.org/), Clarksville, Maryland, United States of America
| | - Akhil Maheshwari
- Global Newborn Society (https://www.globalnewbornsociety.org/), Clarksville, Maryland, United States of America
- Department of Pediatrics, Louisiana State University, Shreveport, Louisiana, United States of America
| | - Suresh Boppana
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| |
Collapse
|
8
|
Bottino P, Pastrone L, Curtoni A, Bondi A, Sidoti F, Zanotto E, Cavallo R, Solidoro P, Costa C. Antiviral Approach to Cytomegalovirus Infection: An Overview of Conventional and Novel Strategies. Microorganisms 2023; 11:2372. [PMID: 37894030 PMCID: PMC10608897 DOI: 10.3390/microorganisms11102372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 10/29/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a herpesvirus capable of establishing a lifelong persistence in the host through a chronic state of infection and remains an essential global concern due to its distinct life cycle, mutations, and latency. It represents a life-threatening pathogen for immunocompromised patients, such as solid organ transplanted patients, HIV-positive individuals, and hematopoietic stem cell recipients. Multiple antiviral approaches are currently available and administered in order to prevent or manage viral infections in the early stages. However, limitations due to side effects and the onset of antidrug resistance are a hurdle to their efficacy, especially for long-term therapies. Novel antiviral molecules, together with innovative approaches (e.g., genetic editing and RNA interference) are currently in study, with promising results performed in vitro and in vivo. Since HCMV is a virus able to establish latent infection, with a consequential risk of reactivation, infection management could benefit from preventive treatment for critical patients, such as immunocompromised individuals and seronegative pregnant women. This review will provide an overview of conventional antiviral clinical approaches and their mechanisms of action. Additionally, an overview of proposed and developing new molecules is provided, including nucleic-acid-based therapies and immune-mediated approaches.
Collapse
Affiliation(s)
- Paolo Bottino
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Lisa Pastrone
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Antonio Curtoni
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Alessandro Bondi
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Francesca Sidoti
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Elisa Zanotto
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Rossana Cavallo
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| | - Paolo Solidoro
- Pneumology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy;
| | - Cristina Costa
- Microbiology and Virology Unit, A.O.U. “Città della Salute e della Scienza di Torino”, 10126 Turin, Italy; (L.P.); (A.C.); (A.B.); (F.S.); (E.Z.); (R.C.)
| |
Collapse
|
9
|
Bogdanow B, Gruska I, Mühlberg L, Protze J, Hohensee S, Vetter B, Bosse JB, Lehmann M, Sadeghi M, Wiebusch L, Liu F. Spatially resolved protein map of intact human cytomegalovirus virions. Nat Microbiol 2023; 8:1732-1747. [PMID: 37550507 PMCID: PMC10465357 DOI: 10.1038/s41564-023-01433-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/20/2023] [Indexed: 08/09/2023]
Abstract
Herpesviruses assemble large enveloped particles that are difficult to characterize structurally due to their size, fragility and complex multilayered proteome with partially amorphous nature. Here we used crosslinking mass spectrometry and quantitative proteomics to derive a spatially resolved interactome map of intact human cytomegalovirus virions. This enabled the de novo allocation of 32 viral proteins into four spatially resolved virion layers, each organized by a dominant viral scaffold protein. The viral protein UL32 engages with all layers in an N-to-C-terminal radial orientation, bridging nucleocapsid to viral envelope. We observed the layer-specific incorporation of 82 host proteins, of which 39 are selectively recruited. We uncovered how UL32, by recruitment of PP-1 phosphatase, antagonizes binding to 14-3-3 proteins. This mechanism assures effective viral biogenesis, suggesting a perturbing role of UL32-14-3-3 interaction. Finally, we integrated these data into a coarse-grained model to provide global insights into the native configuration of virus and host protein interactions inside herpesvirions.
Collapse
Affiliation(s)
- Boris Bogdanow
- Research group 'Structural Interactomics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
| | - Iris Gruska
- Labor für Pädiatrische Molekularbiologie, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Lars Mühlberg
- Research group 'Structural Interactomics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Jonas Protze
- Research group 'Structural Bioinformatics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Svea Hohensee
- Cellular Imaging core facility, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Barbara Vetter
- Labor für Pädiatrische Molekularbiologie, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jens B Bosse
- Centre for Structural Systems Biology, Hamburg, Germany
- Hannover Medical School, Institute of Virology, Hannover, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
- Leibniz-Institute of Virology (LIV), Hamburg, Germany
| | - Martin Lehmann
- Cellular Imaging core facility, Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Mohsen Sadeghi
- Department of Mathematics and Computer Science, Freie Universität Berlin, Berlin, Germany.
| | - Lüder Wiebusch
- Labor für Pädiatrische Molekularbiologie, Department of Pediatric Oncology and Hematology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
| | - Fan Liu
- Research group 'Structural Interactomics', Leibniz Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
- Charité Universitätsmedizin Berlin, Berlin, Germany.
| |
Collapse
|
10
|
Panda K, Parashar D, Viswanathan R. An Update on Current Antiviral Strategies to Combat Human Cytomegalovirus Infection. Viruses 2023; 15:1358. [PMID: 37376657 DOI: 10.3390/v15061358] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/29/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Human cytomegalovirus (HCMV) remains an essential global concern due to its distinct life cycle, mutations and latency. As HCMV is a herpesvirus, it establishes a lifelong persistence in the host through a chronic state of infection. Immunocompromised individuals are at risk of significant morbidity and mortality from the virus. Until now, no effective vaccine has been developed to combat HCMV infection. Only a few antivirals targeting the different stages of the virus lifecycle and viral enzymes are licensed to manage the infection. Therefore, there is an urgent need to find alternate strategies to combat the infection and manage drug resistance. This review will provide an insight into the clinical and preclinical antiviral approaches, including HCMV antiviral drugs and nucleic acid-based therapeutics.
Collapse
Affiliation(s)
- Kingshuk Panda
- Dengue-Chikungunya Group, Indian Council of Medical Research-National Institute of Virology, Pune 411001, India
| | - Deepti Parashar
- Dengue-Chikungunya Group, Indian Council of Medical Research-National Institute of Virology, Pune 411001, India
| | - Rajlakshmi Viswanathan
- Bacteriology Group, Indian Council of Medical Research-National Institute of Virology, Pune 411001, India
| |
Collapse
|
11
|
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.
Collapse
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.
| |
Collapse
|
12
|
Zhang Z, Xie J, Xing J, Li C, Wong TM, Yu H, Li Y, Yang F, Tian Y, Zhang H, Li W, Ning C, Wang X, Yu P. Light-Programmable Nanocomposite Hydrogel for State-Switchable Wound Healing Promotion and Bacterial Infection Elimination. Adv Healthc Mater 2023; 12:e2201565. [PMID: 36208068 DOI: 10.1002/adhm.202201565] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/11/2022] [Indexed: 01/18/2023]
Abstract
Developing an ideal wound dressing that not only accelerates wound healing but also eliminates potential bacterial infections remains a difficult balancing act. This work reports the design of a light-programmable sodium alginate nanocomposite hydrogel loaded with BiOCl/polypyrrole (BOC/PPy) nanosheets for state-switchable wound healing promotion and bacterial infection elimination remotely. The nanocomposite hydrogel possesses programmable photoelectric or photothermal conversion due to the expanded light absorption range, optimized electron transmission interface, promoted photo-generated charge separation, and transfer of the BOC/PPy nanosheets. Under white light irradiation state, the nanocomposite hydrogel induces human umbilical vein endothelial cells migration and angiogenesis, and accelerates the healing efficiency of mouse skin in vivo. Under near-infrared light irradiation state, the nanocomposite hydrogel presents superior antibacterial capability in vitro, and reaches an antibacterial rate of 99.1% for Staphylococcus aureus infected skin wound in vivo. This light-programmable nanocomposite hydrogel provides an on-demand resolution of biological state-switching to balance wound healing and elimination of bacterial infection.
Collapse
Affiliation(s)
- Zhekun Zhang
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Juning Xie
- School of Medicine, South China University of Technology, Guangzhou, 510640, P. R. China.,Medical Research Center, Department of Orthopedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080, P. R. China
| | - Jun Xing
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Changhao Li
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Tak Man Wong
- Department of Orthopaedics and Traumatology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, 999077, China
| | - Hui Yu
- Medical Research Center, Department of Orthopedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080, P. R. China
| | - Yuanxing Li
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Fabang Yang
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Yu Tian
- School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou, 510006, China
| | - Huan Zhang
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Wei Li
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Chengyun Ning
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Xiaolan Wang
- Medical Research Center, Department of Orthopedics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, 510080, P. R. China
| | - Peng Yu
- School of Material Science and Engineering, National Engineering Research Center for Tissue Restoration and Reconstruction, Metallic Materials Surface Functionalization Engineering Research Center of Guangdong Province, South China University of Technology, Guangzhou, 510640, P. R. China
| |
Collapse
|
13
|
Turner DL, Mathias RA. The human cytomegalovirus decathlon: Ten critical replication events provide opportunities for restriction. Front Cell Dev Biol 2022; 10:1053139. [PMID: 36506089 PMCID: PMC9732275 DOI: 10.3389/fcell.2022.1053139] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 11/10/2022] [Indexed: 11/27/2022] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous human pathogen that can cause severe disease in immunocompromised individuals, transplant recipients, and to the developing foetus during pregnancy. There is no protective vaccine currently available, and with only a limited number of antiviral drug options, resistant strains are constantly emerging. Successful completion of HCMV replication is an elegant feat from a molecular perspective, with both host and viral processes required at various stages. Remarkably, HCMV and other herpesviruses have protracted replication cycles, large genomes, complex virion structure and complicated nuclear and cytoplasmic replication events. In this review, we outline the 10 essential stages the virus must navigate to successfully complete replication. As each individual event along the replication continuum poses as a potential barrier for restriction, these essential checkpoints represent potential targets for antiviral development.
Collapse
Affiliation(s)
- Declan L. Turner
- Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Rommel A. Mathias
- Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia,Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia,*Correspondence: Rommel A. Mathias,
| |
Collapse
|
14
|
Borst EM, Harmening S, Sanders S, Caragliano E, Wagner K, Lenac Roviš T, Jonjić S, Bosse JB, Messerle M. A Unique Role of the Human Cytomegalovirus Small Capsid Protein in Capsid Assembly. mBio 2022; 13:e0100722. [PMID: 36066102 PMCID: PMC9600257 DOI: 10.1128/mbio.01007-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 08/11/2022] [Indexed: 11/20/2022] Open
Abstract
Morphogenesis of herpesvirus particles is highly conserved; however, the capsid assembly and genome packaging of human cytomegalovirus (HCMV) exhibit unique features. Examples of these include the essential role of the small capsid protein (SCP) and the existence of the β-herpesvirus-specific capsid-associated protein pp150. SCP and pp150, as well as the UL77 and UL93 proteins, are important capsid constituents, yet their precise mechanism of action is elusive. Here, we analyzed how deletion of the open reading frames (ORFs) encoding pUL77, pUL93, pp150, or SCP affects the protein composition of nuclear capsids. This was achieved by generating HCMV genomes lacking the respective genes, combined with a highly efficient transfection technique that allowed us to directly analyze these mutants in transfected cells. While no obvious effects were observed when pUL77, pUL93, or pp150 was missing, the absence of SCP impeded capsid assembly due to strongly reduced amounts of major capsid protein (MCP). Vice versa, when MCP was lacking, SCP became undetectable, indicating a mutual dependence of SCP and MCP for establishing appropriate protein levels. The SCP domain mediating stable MCP levels could be narrowed down to a C-terminal helix known to convey MCP binding. Interestingly, an SCP-EGFP (enhanced green fluorescent protein) fusion protein which also impaired the production of infectious progeny acted in a different manner, as capsid assembly was not abolished; however, SCP-EGFP-harboring capsids were devoid of DNA and trapped in paracrystalline nuclear structures. These results indicate that SCP is essential in HCMV because of its impact on MCP levels and reveal SCP as a potential target for antiviral inhibitors. IMPORTANCE Human cytomegalovirus (HCMV) is a ubiquitous pathogen causing life-threatening disease in immunocompromised individuals. Virus-specific processes such as capsid assembly and genome packaging can be exploited to design new antiviral strategies. Here, we report on a novel function of the HCMV small capsid protein (SCP), namely, ensuring stable levels of major capsid protein (MCP), thereby governing capsid assembly. Furthermore, we discovered a mutual dependence of the small and major capsid proteins to guarantee appropriate levels of the other respective protein and were able to pin down the SCP domain responsible for this effect to a region previously shown to mediate binding to the major capsid protein. In summary, our data contribute to the understanding of how SCP plays an essential part in the HCMV infection cycle. Moreover, disrupting the SCP-MCP interface may provide a starting point for the development of novel antiviral drugs.
Collapse
Affiliation(s)
- Eva Maria Borst
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Sarah Harmening
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Saskia Sanders
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Enrico Caragliano
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Karen Wagner
- Department of Virology, Hannover Medical School, Hannover, Germany
| | - Tihana Lenac Roviš
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Stipan Jonjić
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Jens Bernhard Bosse
- Department of Virology, Hannover Medical School, Hannover, Germany
- Leibniz-Institute for Experimental Virology, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany
- Cluster of Excellence RESIST (EXC 2155), Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Department of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research, Partner Site Hannover Braunschweig, Hannover, Germany
| |
Collapse
|
15
|
Turner DL, Fritzlar S, Sadeghipour S, Barugahare AA, Russ BE, Turner SJ, Mathias RA. UL49 is an essential subunit of the viral pre-initiation complex that regulates human cytomegalovirus gene transcription. iScience 2022; 25:105168. [PMID: 36204275 PMCID: PMC9530030 DOI: 10.1016/j.isci.2022.105168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/25/2022] [Accepted: 09/16/2022] [Indexed: 11/03/2022] Open
Abstract
More than half the world’s population is infected with human cytomegalovirus (HCMV), causing congenital birth defects and impacting the immuno-compromised. Many of the >170 HCMV genes remain uncharacterized, and this gap in knowledge limits the development of novel antivirals. In this study, we investigated the essential viral protein UL49 and found it displayed leaky late expression kinetics, and localized to nuclear replication compartments. Cells infected with mutant UL49 virus were unable to produce infectious virions and phenocopied other beta-gamma viral pre-initiation complex (vPIC) subunit (UL79, UL87, UL91, UL92, and UL95) mutant infections. RNA-seq analysis of vPIC mutant infections revealed a consistent diminution of genes encoding capsid subunits, including TRX2/UL85 and MCP/UL86, envelope glycoproteins gM, gL and gO, and egress-associated tegument proteins UL99 and UL103. Therefore, as a member of the vPIC, UL49 serves as a fundamental HCMV effector that governs viral gene transcription required to complete the replication cycle. Beta- and gamma-herpes viruses encode a viral pre-initiation complex (vPIC) UL49, together with UL79, UL87, UL91, UL92, and UL95 Comprise the HCMV vPIC UL49 is essential for HCMV replication and orchestrates late viral gene expression Mutation of vPIC subunits reduces the transcription of structural virion components
Collapse
|
16
|
Jarnot P, Ziemska-Legiecka J, Grynberg M, Gruca A. Insights from analyses of low complexity regions with canonical methods for protein sequence comparison. Brief Bioinform 2022; 23:bbac299. [PMID: 35914952 PMCID: PMC9487646 DOI: 10.1093/bib/bbac299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/29/2022] [Accepted: 07/01/2022] [Indexed: 11/28/2022] Open
Abstract
Low complexity regions are fragments of protein sequences composed of only a few types of amino acids. These regions frequently occur in proteins and can play an important role in their functions. However, scientists are mainly focused on regions characterized by high diversity of amino acid composition. Similarity between regions of protein sequences frequently reflect functional similarity between them. In this article, we discuss strengths and weaknesses of the similarity analysis of low complexity regions using BLAST, HHblits and CD-HIT. These methods are considered to be the gold standard in protein similarity analysis and were designed for comparison of high complexity regions. However, we lack specialized methods that could be used to compare the similarity of low complexity regions. Therefore, we investigated the existing methods in order to understand how they can be applied to compare such regions. Our results are supported by exploratory study, discussion of amino acid composition and biological roles of selected examples. We show that existing methods need improvements to efficiently search for similar low complexity regions. We suggest features that have to be re-designed specifically for comparing low complexity regions: scoring matrix, multiple sequence alignment, e-value, local alignment and clustering based on a set of representative sequences. Results of this analysis can either be used to improve existing methods or to create new methods for the similarity analysis of low complexity regions.
Collapse
Affiliation(s)
- Patryk Jarnot
- Department of Computer Networks and Systems, Silesian University of Technology, Akademicka 2A, 44-100, Gliwice, Poland
| | - Joanna Ziemska-Legiecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Marcin Grynberg
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Aleksandra Gruca
- Department of Computer Networks and Systems, Silesian University of Technology, Akademicka 2A, 44-100, Gliwice, Poland
| |
Collapse
|
17
|
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.
Collapse
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.
| |
Collapse
|
18
|
Abstract
Cytomegaloviruses (CMVs) are among the largest pathogenic viruses in mammals. To enable replication of their long double-stranded DNA genomes, CMVs induce profound changes in cell cycle regulation. A hallmark of CMV cell cycle control is the establishment of an unusual cell cycle arrest at the G1/S transition, which is characterized by the coexistence of cell cycle stimulatory and inhibitory activities. While CMVs interfere with cellular DNA synthesis and cell division, they activate S-phase-specific gene expression and nucleotide metabolism. This is facilitated by a set of CMV gene products that target master regulators of G1/S progression such as cyclin E and A kinases, Rb-E2F transcription factors, p53-p21 checkpoint proteins, the APC/C ubiquitin ligase, and the nucleotide hydrolase SAMHD1. While the major themes of cell cycle regulation are well conserved between human and murine CMVs (HCMV and MCMV), there are considerable differences at the level of viral cell cycle effectors and their mechanisms of action. Furthermore, both viruses have evolved unique mechanisms to sense the host cell cycle state and modulate the infection program accordingly. This review provides an overview of conserved and divergent features of G1/S control by MCMV and HCMV.
Collapse
|
19
|
Production- and Purification-Relevant Properties of Human and Murine Cytomegalovirus. Viruses 2021; 13:v13122481. [PMID: 34960750 PMCID: PMC8706497 DOI: 10.3390/v13122481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/01/2021] [Accepted: 12/09/2021] [Indexed: 11/17/2022] Open
Abstract
There is a large unmet need for a prophylactic vaccine against human cytomegalovirus (HCMV) to combat the ubiquitous infection that is ongoing with this pathogen. A vaccination against HCMV could protect immunocompromised patients and prevent birth defects caused by congenital HCMV infections. Moreover, cytomegalovirus (CMV) has a number of features that make it a very interesting vector platform for gene therapy. In both cases, preparation of a highly purified virus is a prerequisite for safe and effective application. Murine CMV (MCMV) is by far the most studied model for HCMV infections with regard to the principles that govern the immune surveillance of CMVs. Knowledge transfer from MCMV and mice to HCMV and humans could be facilitated by better understanding and characterization of the biological and biophysical properties of both viruses. We carried out a detailed investigation of HCMV and MCMV growth kinetics as well as stability under the influence of clarification and different storage conditions. Further, we investigated the possibilities to concentrate and purify both viruses by ultracentrifugation and ion-exchange chromatography. Defective enveloped particles were not separately analyzed; however, the behavior of exosomes was examined during all experiments. The effectiveness of procedures was monitored using CCID50 assay, Nanoparticle tracking analysis, ELISA for host cell proteins, and quantitative PCR for host cell DNA. MCMV generally proved to be more robust in handling. Despite its greater sensitivity, HCMV was efficiently (100% recovery) purified and concentrated by anion-exchange chromatography using QA monolithic support. The majority of the host genomic DNA as well as most of the host cell proteins were removed by this procedure.
Collapse
|
20
|
Tegument Protein pp150 Sequence-Specific Peptide Blocks Cytomegalovirus Infection. Viruses 2021; 13:v13112277. [PMID: 34835083 PMCID: PMC8623180 DOI: 10.3390/v13112277] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 11/17/2022] Open
Abstract
Human cytomegalovirus (HCMV) tegument protein pp150 is essential for the completion of the final steps in virion maturation. Earlier studies indicated that three pp150nt (N-terminal one-third of pp150) conformers cluster on each triplex (Tri1, Tri2A and Tri2B), and extend towards small capsid proteins atop nearby major capsid proteins, forming a net-like layer of tegument densities that enmesh and stabilize HCMV capsids. Based on this atomic detail, we designed several peptides targeting pp150nt. Our data show significant reduction in virus growth upon treatment with one of these peptides (pep-CR2) with an IC50 of 1.33 μM and no significant impact on cell viability. Based on 3D modeling, pep-CR2 specifically interferes with the pp150–capsid binding interface. Cells pre-treated with pep-CR2 and infected with HCMV sequester pp150 in the nucleus, indicating a mechanistic disruption of pp150 loading onto capsids and subsequent nuclear egress. Furthermore, pep-CR2 effectively inhibits mouse cytomegalovirus (MCMV) infection in cell culture, paving the way for future animal testing. Combined, these results indicate that CR2 of pp150 is amenable to targeting by a peptide inhibitor, and can be developed into an effective antiviral.
Collapse
|
21
|
Human Cytomegalovirus UL48 Deubiquitinase Primarily Targets Innermost Tegument Proteins pp150 and Itself To Regulate Their Stability and Protects Virions from Inclusion of Ubiquitin Conjugates. J Virol 2021; 95:e0099121. [PMID: 34549978 DOI: 10.1128/jvi.00991-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral deubiquitinases (DUBs) regulate cellular innate immunity to benefit viral replication. In human cytomegalovirus (HCMV), the UL48-encoded DUB regulates innate immune responses, including NF-κB signaling. Although UL48 DUB is known to regulate its stability via auto-deubiquitination, its impact on other viral proteins is not well understood. In this study, we investigated the role of UL48 DUB in regulating the ubiquitination of viral proteins by comparing the levels of ubiquitinated viral peptides in cells infected with wild-type virus and DUB active-site mutants using mass spectrometry. We found that ubiquitinated peptides were increased in DUB mutant virus infection for 90% of viral proteins, with the innermost tegument proteins pp150 (encoded by UL32) and pUL48 itself being most significantly affected. The highly deubiquitinated lysine residues of pUL48 were mapped within its N-terminal DUB domain and the nuclear localization signal. Among them, the arginine substitution of lysine 2 (K2R) increased pUL48 stability and enhanced viral growth at low multiplicity of infection, indicating that K2 auto-deubiquitination has a role in regulating pUL48 stability. pUL48 also interacted with pp150 and increased pp150 expression by downregulating its ubiquitination. Furthermore, we found that, unlike the wild-type virus, mutant viruses expressing the UL48 protein with the DUB domain deleted or DUB active site mutated contain higher levels of ubiquitin conjugates, including the ubiquitinated forms of pp150, in their virions. Collectively, our results demonstrate that UL48 DUB mainly acts on the innermost tegument proteins pp150 and pUL48 itself during HCMV infection and may play a role in protecting virions from the inclusion of ubiquitin conjugates. IMPORTANCE Herpesviruses encode highly conserved tegument proteins that contain deubiquitinase (DUB) activity. Although the role of viral DUBs in the regulation of host innate immune responses has been established, their roles in the stability and function of viral proteins are not well understood. In this study, we performed a comparative analysis of the levels of ubiquitinated viral peptides between wild-type and DUB-inactive HCMV infections and demonstrated that the innermost tegument proteins pp150 and pUL48 (DUB itself) are major targets of viral DUB. We also show that ubiquitinated viral proteins are effectively incorporated into the virions of DUB mutant viruses but not the wild-type virus. Our study demonstrates that viral DUBs may play important roles in promoting the stability of viral proteins and inhibiting the inclusion of ubiquitin conjugates into virions.
Collapse
|
22
|
Naniima P, Naimo E, Koch S, Curth U, Alkharsah KR, Ströh LJ, Binz A, Beneke JM, Vollmer B, Böning H, Borst EM, Desai P, Bohne J, Messerle M, Bauerfeind R, Legrand P, Sodeik B, Schulz TF, Krey T. Assembly of infectious Kaposi's sarcoma-associated herpesvirus progeny requires formation of a pORF19 pentamer. PLoS Biol 2021; 19:e3001423. [PMID: 34735435 PMCID: PMC8568140 DOI: 10.1371/journal.pbio.3001423] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 09/22/2021] [Indexed: 12/25/2022] Open
Abstract
Herpesviruses cause severe diseases particularly in immunocompromised patients. Both genome packaging and release from the capsid require a unique portal channel occupying one of the 12 capsid vertices. Here, we report the 2.6 Å crystal structure of the pentameric pORF19 of the γ-herpesvirus Kaposi’s sarcoma-associated herpesvirus (KSHV) resembling the portal cap that seals this portal channel. We also present the structure of its β-herpesviral ortholog, revealing a striking structural similarity to its α- and γ-herpesviral counterparts despite apparent differences in capsid association. We demonstrate pORF19 pentamer formation in solution and provide insights into how pentamerization is triggered in infected cells. Mutagenesis in its lateral interfaces blocked pORF19 pentamerization and severely affected KSHV capsid assembly and production of infectious progeny. Our results pave the way to better understand the role of pORF19 in capsid assembly and identify a potential novel drug target for the treatment of herpesvirus-induced diseases. In herpesviruses, genome packaging and release from the capsid require a unique portal channel. Here, the authors have resolved the crystal structure of a pentameric KSHV pORF19 assembly and find that it resembles the herpesviral portal cap and provides insights how the viral genome is retained within the capsid.
Collapse
Affiliation(s)
- Peter Naniima
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
| | - Eleonora Naimo
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
| | - Sandra Koch
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
| | - Ute Curth
- Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany
| | - Khaled R. Alkharsah
- Department of Microbiology, College of Medicine, Imam Abdulrahman Bin Faisal University (IAU), Dammam, Saudi Arabia
| | - Luisa J. Ströh
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Anne Binz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Jan-Marc Beneke
- Center of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Luebeck, Luebeck, Germany
| | - Benjamin Vollmer
- Centre for Structural Systems Biology, Leibniz-Institut für Experimentelle Virologie (HPI), Hamburg, Germany
| | - Heike Böning
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Eva Maria Borst
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Prashant Desai
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, The Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jens Bohne
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Rudolf Bauerfeind
- Research Core Unit Laser Microscopy, Hannover Medical School, Hannover, Germany
| | - Pierre Legrand
- Synchrotron SOLEIL, L’Orme des Merisiers, Gif-sur-Yvette, France
| | - Beate Sodeik
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
| | - Thomas Krey
- Institute of Virology, Hannover Medical School, Hannover, Germany
- German Center for Infection Research (DZIF), partner sites Hannover-Braunschweig and Hamburg-Lübeck-Borstel-Riems, Braunschweig, Germany
- Excellence Cluster 2155 RESIST, Hannover Medical School, Hannover, Germany
- Center of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Luebeck, Luebeck, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
- * E-mail:
| |
Collapse
|
23
|
Draganova EB, Valentin J, Heldwein EE. The Ins and Outs of Herpesviral Capsids: Divergent Structures and Assembly Mechanisms across the Three Subfamilies. Viruses 2021; 13:v13101913. [PMID: 34696343 PMCID: PMC8539031 DOI: 10.3390/v13101913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 12/17/2022] Open
Abstract
Human herpesviruses, classified into three subfamilies, are double-stranded DNA viruses that establish lifelong latent infections within most of the world’s population and can cause severe disease, especially in immunocompromised people. There is no cure, and current preventative and therapeutic options are limited. Therefore, understanding the biology of these viruses is essential for finding new ways to stop them. Capsids play a central role in herpesvirus biology. They are sophisticated vehicles that shelter the pressurized double-stranded-DNA genomes while ensuring their delivery to defined cellular destinations on the way in and out of the host cell. Moreover, the importance of capsids for multiple key steps in the replication cycle makes their assembly an attractive therapeutic target. Recent cryo-electron microscopy reconstructions of capsids from all three subfamilies of human herpesviruses revealed not only conserved features but also remarkable structural differences. Furthermore, capsid assembly studies have suggested subfamily-specific roles of viral capsid protein homologs. In this review, we compare capsid structures, assembly mechanisms, and capsid protein functions across human herpesvirus subfamilies, highlighting the differences.
Collapse
Affiliation(s)
- Elizabeth B. Draganova
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA;
| | - Jonathan Valentin
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32603, USA;
| | - Ekaterina E. Heldwein
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA;
- Correspondence:
| |
Collapse
|
24
|
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.
Collapse
|
25
|
The journey of herpesvirus capsids and genomes to the host cell nucleus. Curr Opin Virol 2021; 50:147-158. [PMID: 34464845 DOI: 10.1016/j.coviro.2021.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/06/2021] [Accepted: 08/09/2021] [Indexed: 01/04/2023]
Abstract
Starting a herpesviral infection is a steeplechase across membranes, cytosol, and nuclear envelopes and against antiviral defence mechanisms. Here, we highlight recent insights on capsid stabilization at the portals during assembly, early capsid-host interactions ensuring nuclear targeting of incoming capsids, and genome uncoating. After fusion with a host membrane, incoming capsids recruit microtubule motors for traveling to the centrosome, and by unknown mechanisms get forward towards the nucleus. The interaction of capsid-associated tegument proteins with nucleoporins orients the capsid portal towards the nuclear pore, and presumably after removal of the portal caps the genomes that have been packaged under pressure can be injected into the nucleoplasm for transcription and replication. Some cell types disarm the incoming capsids or silence the incoming genomes to reduce the likelihood of infection.
Collapse
|
26
|
STING facilitates nuclear import of herpesvirus genome during infection. Proc Natl Acad Sci U S A 2021; 118:2108631118. [PMID: 34385328 DOI: 10.1073/pnas.2108631118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Once inside the host cell, DNA viruses must overcome the physical barrier posed by the nuclear envelope to establish a successful infection. The mechanism underlying this process remains unclear. Here, we show that the herpesvirus exploits the immune adaptor stimulator of interferon genes (STING) to facilitate nuclear import of the viral genome. Following the entry of the viral capsid into the cell, STING binds the viral capsid, mediates capsid docking to the nuclear pore complex via physical interaction, and subsequently enables accumulation of the viral genome in the nucleus. Silencing STING in human cytomegalovirus (HCMV)-susceptible cells inhibited nuclear import of the viral genome and reduced the ensuing viral gene expression. Overexpressing STING increased the host cell's susceptibility to HCMV and herpes simplex virus 1 by improving the nuclear delivery of viral DNA at the early stage of infection. These observations suggest that the proviral activity of STING is conserved and exploited by the herpesvirus family. Intriguingly, in monocytes, which act as latent reservoirs of HCMV, STING deficiency negatively regulated the establishment of HCMV latency and reactivation. Our findings identify STING as a proviral host factor regulating latency and reactivation of herpesviruses.
Collapse
|
27
|
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.
Collapse
|
28
|
Epigenetic reprogramming of host and viral genes by Human Cytomegalovirus infection in Kasumi-3 myeloid progenitor cells at early times post-infection. J Virol 2021; 95:JVI.00183-21. [PMID: 33731453 PMCID: PMC10021080 DOI: 10.1128/jvi.00183-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
HCMV establishes latency in myeloid cells. Using the Kasumi-3 latency model, we previously showed that lytic gene expression is activated prior to establishment of latency in these cells. The early events in infection may have a critical role in shaping establishment of latency. Here, we have used an integrative multi-omics approach to investigate dynamic changes in host and HCMV gene expression and epigenomes at early times post infection. Our results show dynamic changes in viral gene expression and viral chromatin. Analyses of Pol II, H3K27Ac and H3K27me3 occupancy of the viral genome showed that 1) Pol II occupancy was highest at the MIEP at 4 hours post infection. However, it was observed throughout the genome; 2) At 24 hours, H3K27Ac was localized to the major immediate early promoter/enhancer and to a possible second enhancer in the origin of replication OriLyt; 3) viral chromatin was broadly accessible at 24 hpi. In addition, although HCMV infection activated expression of some host genes, we observed an overall loss of de novo transcription. This was associated with loss of promoter-proximal Pol II and H3K27Ac, but not with changes in chromatin accessibility or a switch in modification of H3K27.Importance.HCMV is an important human pathogen in immunocompromised hosts and developing fetuses. Current anti-viral therapies are limited by toxicity and emergence of resistant strains. Our studies highlight emerging concepts that challenge current paradigms of regulation of HCMV gene expression in myeloid cells. In addition, our studies show that HCMV has a profound effect on de novo transcription and the cellular epigenome. These results may have implications for mechanisms of viral pathogenesis.
Collapse
|
29
|
Properties of Oligomeric Interaction of the Cytomegalovirus Core Nuclear Egress Complex (NEC) and Its Sensitivity to an NEC Inhibitory Small Molecule. Viruses 2021; 13:v13030462. [PMID: 33799898 PMCID: PMC8002134 DOI: 10.3390/v13030462] [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: 02/05/2021] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Herpesviral nuclear egress is a regulated process shared by all family members, ensuring the efficient cytoplasmic release of viral capsids. In the case of human cytomegalovirus (HCMV), the core of the nuclear egress complex (NEC) consists of the pUL50-pUL53 heterodimer that builds hexameric lattices for capsid binding and multicomponent interaction, including NEC-associated host factors. A characteristic feature of NEC interaction is the N-terminal hook structure of pUL53 that binds to an alpha-helical groove of pUL50, thus termed as hook-into-groove interaction. This central regulatory element is essential for viral replication and shows structural–functional conservation, which has been postulated as a next-generation target of antiviral strategies. However, a solid validation of this concept has been missing. In the present study, we focused on the properties of oligomeric HCMV core NEC interaction and the antiviral activity of specifically targeted prototype inhibitors. Our data suggest the following: (i) transiently expressed, variably tagged versions of HCMV NEC proteins exert hook-into-groove complexes, putatively in oligomeric assemblies that are distinguishable from heterodimers, as shown by in vitro assembly and coimmunoprecipitation approaches; (ii) this postulated oligomeric binding pattern was further supported by the use of a pUL50::pUL53 fusion construct also showing a pronounced multi-interaction potency; (iii) using confocal imaging cellular NEC-associated proteins were found partly colocalized with the tagged core NECs; (iv) a small inhibitory molecule, recently identified by an in vitro binding inhibition assay, was likewise active in blocking pUL50–pUL53 oligomeric assembly and in exerting antiviral activity in HCMV-infected fibroblasts. In summary, the findings refine the previous concept of HCMV core NEC formation and nominate this drug-accessible complex as a validated antiviral drug target.
Collapse
|
30
|
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.
Collapse
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.)
| |
Collapse
|
31
|
Wang N, Chen W, Zhu L, Zhu D, Feng R, Wang J, Zhu B, Zhang X, Chen X, Liu X, Yan R, Ni D, Zhou GG, Liu H, Rao Z, Wang X. Structures of the portal vertex reveal essential protein-protein interactions for Herpesvirus assembly and maturation. Protein Cell 2020; 11:366-373. [PMID: 32285350 PMCID: PMC7196605 DOI: 10.1007/s13238-020-00711-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Nan Wang
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenyuan Chen
- Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha, 410081, China
| | - Ling Zhu
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Dongjie Zhu
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Rui Feng
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jialing Wang
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Bin Zhu
- Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha, 410081, China
| | - Xinzheng Zhang
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiaoqing Chen
- ImmVira Co., Ltd, Silver Star Hi-tech Industrial Park, Longhua District, Shenzhen, 518116, China
| | - Xianjie Liu
- ImmVira Co., Ltd, Silver Star Hi-tech Industrial Park, Longhua District, Shenzhen, 518116, China
| | - Runbin Yan
- ImmVira Co., Ltd, Silver Star Hi-tech Industrial Park, Longhua District, Shenzhen, 518116, China
| | - Dongyao Ni
- ImmVira Co., Ltd, Silver Star Hi-tech Industrial Park, Longhua District, Shenzhen, 518116, China
| | - Grace Guoying Zhou
- ImmVira Co., Ltd, Silver Star Hi-tech Industrial Park, Longhua District, Shenzhen, 518116, China
| | - Hongrong Liu
- Key Laboratory for Matter Microstructure and Function of Hunan Province, Key Laboratory of Low-dimensional Quantum Structures and Quantum Control, School of Physics and Electronics, Hunan Normal University, Changsha, 410081, China.
| | - Zihe Rao
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
- Laboratory of Structural Biology, Tsinghua University, Beijing, 100084, China.
- State Key Laboratory of Medicinal Chemical Biology, Nankai University, Tianjin, 300353, China.
| | - Xiangxi Wang
- CAS Key Laboratory of Infection and Immunity, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
| |
Collapse
|
32
|
Dedeo CL, Teschke CM, Alexandrescu AT. Keeping It Together: Structures, Functions, and Applications of Viral Decoration Proteins. Viruses 2020; 12:v12101163. [PMID: 33066635 PMCID: PMC7602432 DOI: 10.3390/v12101163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/09/2020] [Accepted: 10/11/2020] [Indexed: 12/14/2022] Open
Abstract
Decoration proteins are viral accessory gene products that adorn the surfaces of some phages and viral capsids, particularly tailed dsDNA phages. These proteins often play a "cementing" role, reinforcing capsids against accumulating internal pressure due to genome packaging, or environmental insults such as extremes of temperature or pH. Many decoration proteins serve alternative functions, including target cell recognition, participation in viral assembly, capsid size determination, or modulation of host gene expression. Examples that currently have structures characterized to high-resolution fall into five main folding motifs: β-tulip, β-tadpole, OB-fold, Ig-like, and a rare knotted α-helical fold. Most of these folding motifs have structure homologs in virus and target cell proteins, suggesting horizontal gene transfer was important in their evolution. Oligomerization states of decoration proteins range from monomers to trimers, with the latter most typical. Decoration proteins bind to a variety of loci on capsids that include icosahedral 2-, 3-, and 5-fold symmetry axes, as well as pseudo-symmetry sites. These binding sites often correspond to "weak points" on the capsid lattice. Because of their unique abilities to bind virus surfaces noncovalently, decoration proteins are increasingly exploited for technology, with uses including phage display, viral functionalization, vaccination, and improved nanoparticle design for imaging and drug delivery. These applications will undoubtedly benefit from further advances in our understanding of these versatile augmenters of viral functions.
Collapse
|
33
|
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.
Collapse
|
34
|
Mata CP, Rodríguez JM, Suzuki N, Castón JR. Structure and assembly of double-stranded RNA mycoviruses. Adv Virus Res 2020; 108:213-247. [PMID: 33837717 DOI: 10.1016/bs.aivir.2020.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mycoviruses are a diverse group that includes ssRNA, dsRNA, and ssDNA viruses, with or without a protein capsid, as well as with a complex envelope. Most mycoviruses are transmitted by cytoplasmic interchange and are thought to lack an extracellular phase in their infection cycle. Structural analysis has focused on dsRNA mycoviruses, which usually package their genome in a 120-subunit T=1 icosahedral capsid, with a capsid protein (CP) dimer as the asymmetric unit. The atomic structure is available for four dsRNA mycovirus from different families: Saccharomyces cerevisiae virus L-A (ScV-L-A), Penicillium chrysogenum virus (PcV), Penicillium stoloniferum virus F (PsV-F), and Rosellinia necatrix quadrivirus 1 (RnQV1). Their capsids show structural variations of the same framework, with asymmetric or symmetric CP dimers respectively for ScV-L-A and PsV-F, dimers of similar domains of a single CP for PcV, or of two different proteins for RnQV1. The CP dimer is the building block, and assembly proceeds through dimers of dimers or pentamers of dimers, in which the genome is packed as ssRNA by interaction with CP and/or viral polymerase. These capsids remain structurally undisturbed throughout the viral cycle. The T=1 capsid participates in RNA synthesis, organizing the viral polymerase (1-2 copies) and a single loosely packaged genome segment. It also acts as a molecular sieve, to allow the passage of viral transcripts and nucleotides, but to prevent triggering of host defense mechanisms. Due to the close mycovirus-host relationship, CP evolved to allocate peptide insertions with enzyme activity, as reflected in a rough outer capsid surface.
Collapse
Affiliation(s)
- Carlos P Mata
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain; Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Javier M Rodríguez
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Nobuhiro Suzuki
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain.
| |
Collapse
|
35
|
Turner DL, Korneev DV, Purdy JG, de Marco A, Mathias RA. The host exosome pathway underpins biogenesis of the human cytomegalovirus virion. eLife 2020; 9:e58288. [PMID: 32910773 PMCID: PMC7556872 DOI: 10.7554/elife.58288] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 08/26/2020] [Indexed: 02/07/2023] Open
Abstract
Human Cytomegalovirus (HCMV) infects over half the world's population, is a leading cause of congenital birth defects, and poses serious risks for immuno-compromised individuals. To expand the molecular knowledge governing virion maturation, we analysed HCMV virions using proteomics, and identified a significant proportion of host exosome constituents. To validate this acquisition, we characterized exosomes released from uninfected cells, and demonstrated that over 99% of the protein cargo was subsequently incorporated into HCMV virions during infection. This suggested a common membrane origin, and utilization of host exosome machinery for virion assembly and egress. Thus, we selected a panel of exosome proteins for knock down, and confirmed that loss of 7/9 caused significantly less HCMV production. Saliently, we report that VAMP3 is essential for viral trafficking and release of infectious progeny, in various HCMV strains and cell types. Therefore, we establish that the host exosome pathway is intrinsic for HCMV maturation, and reveal new host regulators involved in viral trafficking, virion envelopment, and release. Our findings underpin future investigation of host exosome proteins as important modulators of HCMV replication with antiviral potential.
Collapse
Affiliation(s)
- Declan L Turner
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash UniversityVictoriaAustralia
| | - Denis V Korneev
- School of Biological Sciences, Monash UniversityVictoriaAustralia
| | - John G Purdy
- Department of Immunobiology and BIO5 Institute, University of ArizonaTucsonUnited States
| | - Alex de Marco
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash UniversityVictoriaAustralia
- ARC Centre of Excellence in Advanced Molecular Imaging, Monash UniversityVictoriaAustralia
- University of WarwickCoventryUnited Kingdom
| | - Rommel A Mathias
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Microbiology, Monash UniversityVictoriaAustralia
- Infection and Immunity Program, Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash UniversityVictoriaAustralia
| |
Collapse
|
36
|
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.
Collapse
|
37
|
Ye X, Su H, Wrapp D, Freed DC, Li F, Yuan Z, Tang A, Li L, Ku Z, Xiong W, Jaijyan D, Zhu H, Wang D, McLellan JS, Zhang N, Fu TM, An Z. Recognition of a highly conserved glycoprotein B epitope by a bivalent antibody neutralizing HCMV at a post-attachment step. PLoS Pathog 2020; 16:e1008736. [PMID: 32745149 PMCID: PMC7425986 DOI: 10.1371/journal.ppat.1008736] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 08/13/2020] [Accepted: 06/22/2020] [Indexed: 01/13/2023] Open
Abstract
Human cytomegalovirus (HCMV) is one of the main causative agents of congenital viral infection in neonates. HCMV infection also causes serious morbidity and mortality among organ transplant patients. Glycoprotein B (gB) is a major target for HCMV neutralizing antibodies, yet the underlying neutralization mechanisms remain largely unknown. Here we report that 3–25, a gB-specific monoclonal antibody previously isolated from a healthy HCMV-positive donor, efficiently neutralized 14 HCMV strains in both ARPE-19 cells and MRC-5 cells. The core epitope of 3–25 was mapped to a highly conserved linear epitope on antigenic domain 2 (AD-2) of gB. A 1.8 Å crystal structure of 3–25 Fab in complex with the peptide epitope revealed the molecular determinants of 3–25 binding to gB at atomic resolution. Negative-staining electron microscopy (EM) 3D reconstruction of 3–25 Fab in complex with de-glycosylated postfusion gB showed that 3–25 Fab fully occupied the gB trimer at the N-terminus with flexible binding angles. Functionally, 3–25 efficiently inhibited HCMV infection at a post-attachment step by interfering with viral membrane fusion, and restricted post-infection viral spreading in ARPE-19 cells. Interestingly, bivalency was required for HCMV neutralization by AD-2 specific antibody 3–25 but not the AD-4 specific antibody LJP538. In contrast, bivalency was not required for HCMV binding by both antibodies. Taken together, our results reveal the structural basis of gB recognition by 3–25 and demonstrate that inhibition of viral membrane fusion and a requirement of bivalency may be common for gB AD-2 specific neutralizing antibody. HCMV infection is usually asymptomatic in healthy individuals. However, life-threatening diseases frequently accompany HCMV infection in individuals with under-developed or compromised immune systems. Glycoprotein B antigenic domain 2 (AD-2) is a major target for HCMV-neutralizing antibodies that potentially provide immune protection. We report the structure-based study of gB recognition by a potent neutralizing antibody named 3–25 that binds a highly conserved epitope on AD-2. Functionally, 3–25 efficiently inhibited HCMV infection at a post-attachment step by interfering with viral membrane fusion, and restricted post-infection viral spreading. Furthermore, bivalency of 3–25 is required for viral neutralization but not for binding. Our findings advance understanding of gB antibody-mediated HCMV neutralization and facilitate development of gB-targeted vaccines and antibody drugs against HCMV infection.
Collapse
Affiliation(s)
- Xiaohua Ye
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Hang Su
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang, China
| | - Daniel Wrapp
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
| | - Daniel C. Freed
- Merck Research Laboratory, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Fengsheng Li
- Merck Research Laboratory, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Zihao Yuan
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Aimin Tang
- Merck Research Laboratory, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Leike Li
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Zhiqiang Ku
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Wei Xiong
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Dabbu Jaijyan
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America
| | - Hua Zhu
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey, United States of America
| | - Dai Wang
- Merck Research Laboratory, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
| | - Jason S. McLellan
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, United States of America
| | - Ningyan Zhang
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail: (NZ); (TMF); (ZA)
| | - Tong-Ming Fu
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Merck Research Laboratory, Merck & Co., Inc., Kenilworth, New Jersey, United States of America
- * E-mail: (NZ); (TMF); (ZA)
| | - Zhiqiang An
- Texas Therapeutics Institute, Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail: (NZ); (TMF); (ZA)
| |
Collapse
|
38
|
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.
Collapse
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.
| |
Collapse
|
39
|
Hardy JM, Dunstan RA, Grinter R, Belousoff MJ, Wang J, Pickard D, Venugopal H, Dougan G, Lithgow T, Coulibaly F. The architecture and stabilisation of flagellotropic tailed bacteriophages. Nat Commun 2020; 11:3748. [PMID: 32719311 PMCID: PMC7385642 DOI: 10.1038/s41467-020-17505-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 07/01/2020] [Indexed: 12/31/2022] Open
Abstract
Flagellotropic bacteriophages engage flagella to reach the bacterial surface as an effective means to increase the capture radius for predation. Structural details of these viruses are of great interest given the substantial drag forces and torques they face when moving down the spinning flagellum. We show that the main capsid and auxiliary proteins form two nested chainmails that ensure the integrity of the bacteriophage head. Core stabilising structures are conserved in herpesviruses suggesting their ancestral origin. The structure of the tail also reveals a robust yet pliable assembly. Hexameric rings of the tail-tube protein are braced by the N-terminus and a β-hairpin loop, and interconnected along the tail by the splayed β-hairpins. By contrast, we show that the β-hairpin has an inhibitory role in the tail-tube precursor, preventing uncontrolled self-assembly. Dyads of acidic residues inside the tail-tube present regularly-spaced motifs well suited to DNA translocation into bacteria through the tail.
Collapse
Affiliation(s)
- Joshua M Hardy
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Rhys A Dunstan
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Rhys Grinter
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Matthew J Belousoff
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Jiawei Wang
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia
| | - Derek Pickard
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Hariprasad Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC, Australia
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, CB10 1SA, UK
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge, UK
| | - Trevor Lithgow
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Microbiology, Monash University, Clayton, VIC, Australia.
| | - Fasséli Coulibaly
- Infection & Immunity Program, Biomedicine Discovery Institute & Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia.
| |
Collapse
|
40
|
Wang YQ, Zhao XY. Human Cytomegalovirus Primary Infection and Reactivation: Insights From Virion-Carried Molecules. Front Microbiol 2020; 11:1511. [PMID: 32765441 PMCID: PMC7378892 DOI: 10.3389/fmicb.2020.01511] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 06/10/2020] [Indexed: 12/12/2022] Open
Abstract
Human cytomegalovirus (HCMV), a ubiquitous beta-herpesvirus, is able to establish lifelong latency after initial infection. Periodical reactivation occurs after immunosuppression, remaining a major cause of death in immunocompromised patients. HCMV has to reach a structural and functional balance with the host at its earliest entry. Virion-carried mediators are considered to play pivotal roles in viral adaptation into a new cellular environment upon entry. Additionally, one clear difference between primary infection and reactivation is the idea that virion-packaged factors are already formed such that those molecules can be used swiftly by the virus. In contrast, virion-carried mediators have to be transcribed and translated; thus, they are not readily available during reactivation. Hence, understanding virion-carried molecules helps to elucidate HCMV reactivation. In this article, the impact of virion-packaged molecules on viral structure, biological behavior, and viral life cycle will be reviewed.
Collapse
Affiliation(s)
- Yu-Qing Wang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Key Laboratory of Hematopoietic Stem Cell Transplantation, Beijing, China.,PKU-THU Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Xiang-Yu Zhao
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Key Laboratory of Hematopoietic Stem Cell Transplantation, Beijing, China
| |
Collapse
|
41
|
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.
Collapse
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.
| |
Collapse
|
42
|
Couté Y, Kraut A, Zimmermann C, Büscher N, Hesse AM, Bruley C, De Andrea M, Wangen C, Hahn F, Marschall M, Plachter B. Mass Spectrometry-Based Characterization of the Virion Proteome, Phosphoproteome, and Associated Kinase Activity of Human Cytomegalovirus. Microorganisms 2020; 8:microorganisms8060820. [PMID: 32486127 PMCID: PMC7357008 DOI: 10.3390/microorganisms8060820] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 05/28/2020] [Accepted: 05/28/2020] [Indexed: 12/17/2022] Open
Abstract
The assembly of human cytomegalovirus (HCMV) virions is an orchestrated process that requires, as an essential prerequisite, the complex crosstalk between viral structural proteins. Currently, however, the mechanisms governing the successive steps in the constitution of virion protein complexes remain elusive. Protein phosphorylation is a key regulator determining the sequential changes in the conformation, binding, dynamics, and stability of proteins in the course of multiprotein assembly. In this review, we present a comprehensive map of the HCMV virion proteome, including a refined view on the virion phosphoproteome, based on previous publications supplemented by new results. Thus, a novel dataset of viral and cellular proteins contained in HCMV virions is generated, providing a basis for future analyses of individual phosphorylation steps and sites involved in the orchestrated assembly of HCMV virion-specific multiprotein complexes. Finally, we present the current knowledge on the activity of pUL97, the HCMV-encoded and virion-associated kinase, in phosphorylating viral and host proteins.
Collapse
Affiliation(s)
- Yohann Couté
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
- Correspondence: (Y.C.); (B.P.); Tel.: +33-4-38789461 (Y.C.); +49-6131-179232 (B.P.)
| | - Alexandra Kraut
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
| | - Christine Zimmermann
- Institute for Virology and Forschungszentrum für Immuntherapie, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany; (C.Z.); (N.B.)
| | - Nicole Büscher
- Institute for Virology and Forschungszentrum für Immuntherapie, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany; (C.Z.); (N.B.)
| | - Anne-Marie Hesse
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
| | - Christophe Bruley
- University Grenoble Alpes, CEA, Inserm, BIG-BGE, 38000 Grenoble, France; (A.K.); (A.-M.H.); (C.B.)
| | - Marco De Andrea
- Department of Public Health and Pediatric Sciences, Turin Medical School, University of Turin, 10126 Turin, and CAAD – Center for Translational Research on Autoimmune and Allergic Disease, Novara Medical School, 28100 Novara, Italy;
| | - Christina Wangen
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (F.H.); (M.M.)
| | - Friedrich Hahn
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (F.H.); (M.M.)
| | - Manfred Marschall
- Institute for Clinical and Molecular Virology, Friedrich-Alexander University of Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (C.W.); (F.H.); (M.M.)
| | - Bodo Plachter
- Institute for Virology and Forschungszentrum für Immuntherapie, University Medical Center of the Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany; (C.Z.); (N.B.)
- Correspondence: (Y.C.); (B.P.); Tel.: +33-4-38789461 (Y.C.); +49-6131-179232 (B.P.)
| |
Collapse
|
43
|
Past and ongoing adaptation of human cytomegalovirus to its host. PLoS Pathog 2020; 16:e1008476. [PMID: 32384127 PMCID: PMC7239485 DOI: 10.1371/journal.ppat.1008476] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 05/20/2020] [Accepted: 03/13/2020] [Indexed: 12/18/2022] Open
Abstract
Cytomegaloviruses (order Herpesvirales) display remarkable species-specificity as a result of long-term co-evolution with their mammalian hosts. Human cytomegalovirus (HCMV) is exquisitely adapted to our species and displays high genetic diversity. We leveraged information on inter-species divergence of primate-infecting cytomegaloviruses and intra-species diversity of clinical isolates to provide a genome-wide picture of HCMV adaptation across different time-frames. During adaptation to the human host, core viral genes were commonly targeted by positive selection. Functional characterization of adaptive mutations in the primase gene (UL70) indicated that selection favored amino acid replacements that decrease viral replication in human fibroblasts, suggesting evolution towards viral temperance. HCMV intra-species diversity was largely governed by immune system-driven selective pressure, with several adaptive variants located in antigenic domains. A significant excess of positively selected sites was also detected in the signal peptides (SPs) of viral proteins, indicating that, although they are removed from mature proteins, SPs can contribute to viral adaptation. Functional characterization of one of these SPs indicated that adaptive variants modulate the timing of cleavage by the signal peptidase and the dynamics of glycoprotein intracellular trafficking. We thus used evolutionary information to generate experimentally-testable hypotheses on the functional effect of HCMV genetic diversity and we define modulators of viral phenotypes. Human cytomegalovirus (HCMV), which represents the most common infectious cause of birth defects, is perfectly adapted to infect humans. We performed a two-tier analysis of HCMV evolution, by describing selective events that occurred during HCMV adaptation to our species and by identifying more recently emerged adaptive variants in clinical isolates. We show that distinct viral genes were targeted by natural selection over different time frames and we generate a catalog of adaptive variants that represent candidate determinants of viral phenotypic variation. As a proof of concept, we show that adaptive changes in the viral primase modulate viral growth in vitro and that selected variants in the UL144 signal peptide affect glycoprotein intracellular trafficking.
Collapse
|
44
|
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.
| |
Collapse
|
45
|
Luque D, Castón JR. Cryo-electron microscopy for the study of virus assembly. Nat Chem Biol 2020; 16:231-239. [PMID: 32080621 DOI: 10.1038/s41589-020-0477-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 01/13/2020] [Indexed: 12/11/2022]
Abstract
Although viruses are extremely diverse in shape and size, evolution has led to a limited number of viral classes or lineages, which is probably linked to the assembly constraints of a viable capsid. Viral assembly mechanisms are restricted to two general pathways, (i) co-assembly of capsid proteins and single-stranded nucleic acids and (ii) a sequential mechanism in which scaffolding-mediated capsid precursor assembly is followed by genome packaging. Cryo-electron microscopy (cryo-EM) and cryo-electron tomography (cryo-ET), which are revolutionizing structural biology, are central to determining the high-resolution structures of many viral assemblies as well as those of assembly intermediates. This wealth of cryo-EM data has also led to the development and redesign of virus-based platforms for biomedical and biotechnological applications. In this Review, we will discuss recent viral assembly analyses by cryo-EM and cryo-ET showing how natural assembly mechanisms are used to encapsulate heterologous cargos including chemicals, enzymes, and/or nucleic acids for a variety of nanotechnological applications.
Collapse
Affiliation(s)
- Daniel Luque
- Centro Nacional de Microbiología/ISCIII, Majadahonda, Madrid, Spain
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus Cantoblanco, Madrid, Spain.
| |
Collapse
|
46
|
Adamson CS, Nevels MM. Bright and Early: Inhibiting Human Cytomegalovirus by Targeting Major Immediate-Early Gene Expression or Protein Function. Viruses 2020; 12:v12010110. [PMID: 31963209 PMCID: PMC7019229 DOI: 10.3390/v12010110] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/11/2022] Open
Abstract
The human cytomegalovirus (HCMV), one of eight human herpesviruses, establishes lifelong latent infections in most people worldwide. Primary or reactivated HCMV infections cause severe disease in immunosuppressed patients and congenital defects in children. There is no vaccine for HCMV, and the currently approved antivirals come with major limitations. Most approved HCMV antivirals target late molecular processes in the viral replication cycle including DNA replication and packaging. “Bright and early” events in HCMV infection have not been exploited for systemic prevention or treatment of disease. Initiation of HCMV replication depends on transcription from the viral major immediate-early (IE) gene. Alternative transcripts produced from this gene give rise to the IE1 and IE2 families of viral proteins, which localize to the host cell nucleus. The IE1 and IE2 proteins are believed to control all subsequent early and late events in HCMV replication, including reactivation from latency, in part by antagonizing intrinsic and innate immune responses. Here we provide an update on the regulation of major IE gene expression and the functions of IE1 and IE2 proteins. We will relate this insight to experimental approaches that target IE gene expression or protein function via molecular gene silencing and editing or small chemical inhibitors.
Collapse
|
47
|
Abstract
The human betaherpesviruses, human cytomegalovirus (HCMV; species Human betaherpesvirus 5) and human herpesviruses 6A, 6B, and 7 (HHV-6A, -6B, and -7; species Human betaherpesviruses 6A, 6B, and 7) are highly prevalent and can cause severe disease in immune-compromised and immune-naive populations in well- and under-developed communities. Herpesvirus virion assembly is an intricate process that requires viral orchestration of host systems. In this review, we describe recent advances in some of the many cellular events relevant to assembly and egress of betaherpesvirus virions. These include modifications of host metabolic, immune, and autophagic/recycling systems. In addition, we discuss unique aspects of betaherpesvirus virion structure, virion assembly, and the cellular pathways employed during virion egress.
Collapse
|
48
|
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.
Collapse
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.
| |
Collapse
|
49
|
Lee JH, Pasquarella JR, Kalejta RF. Cell Line Models for Human Cytomegalovirus Latency Faithfully Mimic Viral Entry by Macropinocytosis and Endocytosis. J Virol 2019; 93:e01021-19. [PMID: 31391271 PMCID: PMC6803280 DOI: 10.1128/jvi.01021-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 08/05/2019] [Indexed: 02/06/2023] Open
Abstract
Human cytomegalovirus (HCMV) enters primary CD34+ hematopoietic progenitor cells by macropinocytosis, where it establishes latency in part because its tegument-transactivating protein, pp71, remains associated with endosomes and is therefore unable to initiate productive, lytic replication. Here we show that multiple HCMV strains also enter cell line models used to study latency by macropinocytosis and endocytosis. In all latency models tested, tegument-delivered pp71 was found to be colocalized with endosomal markers and was not associated with the seven other cytoplasmic localization markers tested. Like the capsid-associated pp150 tegument protein, we initially detected capsid proteins in association with endosomes but later detected them in the nucleus. Inhibitors of macropinocytosis and endocytosis reduced latent viral gene expression and precluded reactivation. Importantly, we utilized electron microscopy to observe entry by macropinocytosis and endocytosis, providing additional visual corroboration of the findings of our functional studies. Our demonstration that HCMV enters cell line models for latency in a manner indistinguishable from that of its entry into primary cells illustrates the utility of these cell lines for probing the mechanisms, host genetics, and small-molecule-mediated inhibition of HCMV entry into the cell types where it establishes latency.IMPORTANCE Primary cells cultured in vitro currently provide the highest available relevance for examining molecular and genetic requirements for the establishment, maintenance, and reactivation of HCMV latency. However, their expense, heterogeneity, and intransigence to both long-term culture and molecular or genetic modification create rigor and reproducibility challenges for HCMV latency studies. There are several cell line models for latency not obstructed by deficiencies inherent in primary cells. However, many researchers view cell line studies of latency to be physiologically irrelevant because of the perception that these models display numerous and significant differences from primary cells. Here, we show that the very first step in a latent HCMV infection, entry of the virus into cells, occurs in cell line models in a manner indistinguishable from that in which it occurs in primary CD34+ hematopoietic progenitor cells. Our data argue that experimental HCMV latency is much more similar than it is different in cell lines and primary cells.
Collapse
Affiliation(s)
- Jeong-Hee Lee
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Joseph R Pasquarella
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Robert F Kalejta
- Institute for Molecular Virology and McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, Wisconsin, USA
| |
Collapse
|
50
|
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: 23] [Impact Index Per Article: 4.6] [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.
Collapse
|