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Nemerow GR. Integrin-Targeting Strategies for Adenovirus Gene Therapy. Viruses 2024; 16:770. [PMID: 38793651 PMCID: PMC11125847 DOI: 10.3390/v16050770] [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: 04/19/2024] [Revised: 05/07/2024] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Numerous human adenovirus (AdV) types are endowed with arginine-glycine-aspartic acid (RGD) sequences that enable them to recognize vitronectin-binding (αv) integrins. These RGD-binding cell receptors mediate AdV entry into host cells, a crucial early step in virus infection. Integrin interactions with adenoviruses not only initiate receptor-mediated endocytosis but also facilitate AdV capsid disassembly, a prerequisite for membrane penetration by AdV protein VI. This review discusses fundamental aspects of AdV-host interactions mediated by integrins. Recent efforts to re-engineer AdV vectors and non-viral nanoparticles to target αv integrins for bioimaging and the eradication of cancer cells will also be discussed.
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Affiliation(s)
- Glen R Nemerow
- Department of Immunology, The Scripps Research Institute, 10666 North Torrey Pines Rd, La Jolla, CA 92037, USA
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2
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Uribe FR, González VPI, Kalergis AM, Soto JA, Bohmwald K. Understanding the Neurotrophic Virus Mechanisms and Their Potential Effect on Systemic Lupus Erythematosus Development. Brain Sci 2024; 14:59. [PMID: 38248274 PMCID: PMC10813552 DOI: 10.3390/brainsci14010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/24/2023] [Accepted: 01/03/2024] [Indexed: 01/23/2024] Open
Abstract
Central nervous system (CNS) pathologies are a public health concern, with viral infections one of their principal causes. These viruses are known as neurotropic pathogens, characterized by their ability to infiltrate the CNS and thus interact with various cell populations, inducing several diseases. The immune response elicited by neurotropic viruses in the CNS is commanded mainly by microglia, which, together with other local cells, can secrete inflammatory cytokines to fight the infection. The most relevant neurotropic viruses are adenovirus (AdV), cytomegalovirus (CMV), enterovirus (EV), Epstein-Barr Virus (EBV), herpes simplex virus type 1 (HSV-1), and herpes simplex virus type 2 (HSV-2), lymphocytic choriomeningitis virus (LCMV), and the newly discovered SARS-CoV-2. Several studies have associated a viral infection with systemic lupus erythematosus (SLE) and neuropsychiatric lupus (NPSLE) manifestations. This article will review the knowledge about viral infections, CNS pathologies, and the immune response against them. Also, it allows us to understand the relevance of the different viral proteins in developing neuronal pathologies, SLE and NPSLE.
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Affiliation(s)
- Felipe R. Uribe
- Millennium Institute on Immunology and Immunotherapy, Laboratorio de Inmunología Traslacional, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile; (F.R.U.); (V.P.I.G.)
| | - Valentina P. I. González
- Millennium Institute on Immunology and Immunotherapy, Laboratorio de Inmunología Traslacional, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile; (F.R.U.); (V.P.I.G.)
| | - Alexis M. Kalergis
- Millennium Institute on Immunology and Immunotherapy, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8330025, Chile;
- Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Jorge A. Soto
- Millennium Institute on Immunology and Immunotherapy, Laboratorio de Inmunología Traslacional, Departamento de Ciencias Biológicas, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370146, Chile; (F.R.U.); (V.P.I.G.)
| | - Karen Bohmwald
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma, Santiago 8910060, Chile
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3
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Franzo G, Faustini G, Tucciarone CM, Pasotto D, Legnardi M, Cecchinato M. Conflicting Evidence between Clinical Perception and Molecular Epidemiology: The Case of Fowl Adenovirus D. Animals (Basel) 2023; 13:3851. [PMID: 38136888 PMCID: PMC10741239 DOI: 10.3390/ani13243851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Revised: 12/08/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023] Open
Abstract
Fowl adenoviruses (FAdVs, species FAdV-A/-E) are responsible for several clinical syndromes reported with increasing frequency in poultry farms in the last decades. In the present study, a phylodynamic analysis was performed on a group of FAdV-D Hexon sequences with adequate available metadata. The obtained results demonstrated the long-term circulation of this species, at least several decades before the first identification of the disease. After a period of progressive increase, the viral population showed a high-level circulation from approximately the 1960s to the beginning of the new millennium, mirroring the expansion of intensive poultry production and animal trade. At the same time, strain migration occurred mainly from Europe to other continents, although other among-continent connections were estimated. Thereafter, the viral population declined progressively, likely due to the improved control measures, potentially including the development and application of FAdV vaccines. An increase in the viral evolutionary rate featured this phase. A role of vaccine-induced immunity in shaping viral evolution could thus be hypothesized. Accordingly, several sites of the Hexon, especially those targeted by the host response were proven under a significant pervasive or episodic diversifying selection. The present study results demonstrate the role of intensive poultry production and market globalization in the rise of FAdV. The applied control strategies, on the other hand, were effective in limiting viral circulation and shaping its evolution.
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Affiliation(s)
- Giovanni Franzo
- Department of Animal Medicine, Production and Health, University of Padua, Viale dell’Università, 16, 35020 Legnaro, Italy; (G.F.); (C.M.T.); (D.P.); (M.L.); (M.C.)
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Wagner N, Shayakhmetov DM, Stewart PL. Structural Model for Factor X Inhibition of IgM and Complement-Mediated Neutralization of Adenovirus. Viruses 2023; 15:1343. [PMID: 37376642 PMCID: PMC10305487 DOI: 10.3390/v15061343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 05/30/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Adenovirus has strong therapeutic potential as an oncolytic virus and gene therapy vector. However, injecting human species C serotype 5 adenovirus, HAdv-C5, into the bloodstream leads to numerous interactions with plasma proteins that affect viral tropism and biodistribution, and can lead to potent immune responses and viral neutralization. The HAdv/factor X (FX) interaction facilitates highly efficient liver transduction and protects virus particles from complement-mediated neutralization after intravenous delivery. Ablating the FX interaction site on the HAdv-C5 capsid leaves the virus susceptible to neutralization by natural IgM followed by activation of the complement cascade and covalent binding of complement components C4b and C3b to the viral capsid. Here we present structural models for IgM and complement components C1, C4b, and C3b in complex with HAdv-C5. Molecular dynamics simulations indicate that when C3b binds near the vertex, multiple stabilizing interactions can be formed between C3b, penton base, and fiber. These interactions may stabilize the vertex region of the capsid and prevent release of the virally encoded membrane lytic factor, protein VI, which is packaged inside of the viral capsid, thus effectively neutralizing the virus. In a situation where FX and IgM are competing for binding to the capsid, IgM may not be able to form a bent conformation in which most of its Fab arms interact with the capsid. Our structural modeling of the competitive interaction of FX and IgM with HAdv-C5 allows us to propose a mechanistic model for FX inhibition of IgM-mediated virus neutralization. According to this model, although IgM may bind to the capsid, in the presence of FX it will likely retain a planar conformation and thus be unable to promote activation of the complement cascade at the virus surface.
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Affiliation(s)
- Nicole Wagner
- Cleveland Center for Membrane and Structural Biology, Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA;
| | - Dmitry M. Shayakhmetov
- Lowance Center for Human Immunology, Departments of Pediatrics and Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA;
- Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA
- Discovery and Developmental Therapeutics Program, Winship Cancer Institute of Emory University, Atlanta, GA 30322, USA
| | - Phoebe L. Stewart
- Cleveland Center for Membrane and Structural Biology, Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106, USA;
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Ismail AM, Saha A, Lee JS, Painter DF, Chen Y, Singh G, Condezo GN, Chodosh J, San Martín C, Rajaiya J. RANBP2 and USP9x regulate nuclear import of adenovirus minor coat protein IIIa. PLoS Pathog 2022; 18:e1010588. [PMID: 35709296 PMCID: PMC9242475 DOI: 10.1371/journal.ppat.1010588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 06/29/2022] [Accepted: 05/11/2022] [Indexed: 11/30/2022] Open
Abstract
As intracellular parasites, viruses exploit cellular proteins at every stage of infection. Adenovirus outbreaks are associated with severe acute respiratory illnesses and conjunctivitis, with no specific antiviral therapy available. An adenoviral vaccine based on human adenovirus species D (HAdV-D) is currently in use for COVID-19. Herein, we investigate host interactions of HAdV-D type 37 (HAdV-D37) protein IIIa (pIIIa), identified by affinity purification and mass spectrometry (AP-MS) screens. We demonstrate that viral pIIIa interacts with ubiquitin-specific protease 9x (USP9x) and Ran-binding protein 2 (RANBP2). USP9x binding did not invoke its signature deubiquitination function but rather deregulated pIIIa-RANBP2 interactions. In USP9x-knockout cells, viral genome replication and viral protein expression increased compared to wild type cells, supporting a host-favored mechanism for USP9x. Conversely, RANBP2-knock down reduced pIIIa transport to the nucleus, viral genome replication, and viral protein expression. Also, RANBP2-siRNA pretreated cells appeared to contain fewer mature viral particles. Transmission electron microscopy of USP9x-siRNA pretreated, virus-infected cells revealed larger than typical paracrystalline viral arrays. RANBP2-siRNA pretreatment led to the accumulation of defective assembly products at an early maturation stage. CRM1 nuclear export blockade by leptomycin B led to the retention of pIIIa within cell nuclei and hindered pIIIa-RANBP2 interactions. In-vitro binding analyses indicated that USP9x and RANBP2 bind to C-terminus of pIIIa amino acids 386–563 and 386–510, respectively. Surface plasmon resonance testing showed direct pIIIa interaction with recombinant USP9x and RANBP2 proteins, without competition. Using an alternative and genetically disparate adenovirus type (HAdV-C5), we show that the demonstrated pIIIa interaction is also important for a severe respiratory pathogen. Together, our results suggest that pIIIa hijacks RANBP2 for nuclear import and subsequent virion assembly. USP9x counteracts this interaction and negatively regulates virion synthesis. This analysis extends the scope of known adenovirus-host interactions and has potential implications in designing new antiviral therapeutics. The compact genomes of viruses must code for proteins with multiple functions, including those that assist with cell entry, replication, and escape from the host immune defenses. Viruses succeed in every stage of this process by hijacking critical cellular proteins for their propagation. Hence, identifying virus-host protein interactions may permit identifying therapeutic applications that restrict viral processes. Human adenovirus structural proteins link together to produce infectious virions. Protein IIIa is required to assemble fully packaged virions, but its interactions with host factors are unknown. Here, we identify novel host protein interactions of pIIIa with cellular RANBP2 and USP9x. We demonstrate that by interacting with cellular RANBP2, viral pIIIa gains entry to the nucleus for subsequent virion assembly and replication. Reduced RANBP2 expression inhibited pIIIa entry into the nucleus, minimized viral replication and viral protein expression, and led to accumulation of defective assembly products in the infected cells. As a defense against viral infection, USP9x reduces the interaction between pIIIa and RANBP2, resulting in decreased viral propagation. We also show that the identified pIIIa-host interactions are crucial in two disparate HAdV types with diverse disease implications.
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Affiliation(s)
- Ashrafali M. Ismail
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Amrita Saha
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Ji S. Lee
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - David F. Painter
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yinghua Chen
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Gurdeep Singh
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gabriela N. Condezo
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Madrid, Spain
| | - James Chodosh
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Carmen San Martín
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, Madrid, Spain
| | - Jaya Rajaiya
- Department of Ophthalmology, Viral Pathogenesis Laboratory, Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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6
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Structure of a Cell Entry Defective Human Adenovirus Provides Insights into Precursor Proteins and Capsid Maturation. J Mol Biol 2022; 434:167350. [PMID: 34774568 PMCID: PMC8752480 DOI: 10.1016/j.jmb.2021.167350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 02/01/2023]
Abstract
Maturation of adenoviruses is distinguished by proteolytic processing of several interior minor capsid proteins and core proteins by the adenoviral protease and subsequent reorganization of adenovirus core. We report the results derived from the icosahedrally averaged cryo-EM structure of a cell entry defective form of adenovirus, designated ts1, at a resolution of 3.7 Å as well as of the localized reconstructions of unique hexons and penton base. The virion structure revealed the structures and organization of precursors of minor capsid proteins, pIIIa, pVI and pVIII, which are closely associated with the hexons on the capsid interior. In addition to a well-ordered helical domain (a.a. 310-397) of pIIIa, highlights of the structure include the precursors of VIII display significantly different structures near the cleavage sites. Moreover, we traced residues 4-96 of the membrane lytic protein (pVI) that includes an amphipathic helix occluded deep in the hexon cavity suggesting the possibility of co-assembly of hexons with the precursors of VI. In addition, we observe a second copy of pVI ordered up to residue L40 in the peripentonal hexons and a few fragments of density corresponding to 2nd and 3rd copies of pVI in other hexons. However, we see no evidence of precursors of VII binding in the hexon cavity. These findings suggest the possibility that differently bound pVI molecules undergo processing at the N-terminal cleavage sites at varying efficiencies, subsequently creating competition between the cleaved and uncleaved forms of VI, followed by reorganization, processing, and release of VI molecules from the hexon cavities.
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7
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Adenovirus Structure: What Is New? Int J Mol Sci 2021; 22:ijms22105240. [PMID: 34063479 PMCID: PMC8156859 DOI: 10.3390/ijms22105240] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 02/06/2023] Open
Abstract
Adenoviruses are large (~950 Å) and complex non-enveloped, dsDNA icosahedral viruses. They have a pseudo-T = 25 triangulation number with at least 12 different proteins composing the virion. These include the major and minor capsid proteins, core proteins, maturation protease, terminal protein, and packaging machinery. Although adenoviruses have been studied for more than 60 years, deciphering their architecture has presented a challenge for structural biology techniques. An outstanding event was the first near-atomic resolution structure of human adenovirus type 5 (HAdV-C5), solved by cryo-electron microscopy (cryo-EM) in 2010. Discovery of new adenovirus types, together with methodological advances in structural biology techniques, in particular cryo-EM, has lately produced a considerable amount of new, high-resolution data on the organization of adenoviruses belonging to different species. In spite of these advances, the organization of the non-icosahedral core is still a great unknown. Nevertheless, alternative techniques such as atomic force microscopy (AFM) are providing interesting glimpses on the role of the core proteins in genome condensation and virion stability. Here we summarize the current knowledge on adenovirus structure, with an emphasis on high-resolution structures obtained since 2010.
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Kulanayake S, Tikoo SK. Adenovirus Core Proteins: Structure and Function. Viruses 2021; 13:v13030388. [PMID: 33671079 PMCID: PMC7998265 DOI: 10.3390/v13030388] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 01/04/2023] Open
Abstract
Adenoviruses have served as a model for investigating viral-cell interactions and discovering different cellular processes, such as RNA splicing and DNA replication. In addition, the development and evaluation of adenoviruses as the viral vectors for vaccination and gene therapy has led to detailed investigations about adenovirus biology, including the structure and function of the adenovirus encoded proteins. While the determination of the structure and function of the viral capsid proteins in adenovirus biology has been the subject of numerous reports, the last few years have seen increased interest in elucidating the structure and function of the adenovirus core proteins. Here, we provide a review of research about the structure and function of the adenovirus core proteins in adenovirus biology.
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Affiliation(s)
- Shermila Kulanayake
- Vaccine and Infectious Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, Saskatoon, SK S7N5E3, Canada;
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N5E3, Canada
| | - Suresh K. Tikoo
- Vaccine and Infectious Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, Saskatoon, SK S7N5E3, Canada;
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N5E3, Canada
- Correspondence:
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Identification of Two Novel Linear Neutralizing Epitopes within the Hexon Protein of Canine Adenovirus Using Monoclonal Antibodies. Vaccines (Basel) 2021; 9:vaccines9020135. [PMID: 33567652 PMCID: PMC7914820 DOI: 10.3390/vaccines9020135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/02/2021] [Accepted: 02/04/2021] [Indexed: 11/30/2022] Open
Abstract
Canine adenovirus (CAdV) has a high prevalence in canine populations. High affinity neutralizing antibodies against conserved epitopes can provide protective immunity against CAdV and protect against future outbreaks. In this study, we identified two CAdV-2-specific neutralizing monoclonal antibodies (mAbs), 2C1 and 7D7, which recognized two linear-dependent epitopes. MAb 2C1 potently neutralized CAdV-2 with a 50% neutralization titer (NT50) of 4096, and mAb 7D7 partially neutralized CAdV-2 with a 50% NT50 of 64. Immunoprecipitation, Western blot and protein spectral analysis indicated that both neutralizing mAbs recognized the hexon protein (Hex) of CAdV-2. Through a 12-mer random peptide phage display and synthetic peptides analysis, we finely mapped the neutralizing epitopes to two 10-amino acid (aa) peptides within the CAdV Hex: 634RIKQRETPAL643 located on the surface region; and 736PESYKDRMYS745 located in the inner region of the expected 3D structure of trimeric Hex. Importantly, the two epitopes are highly conserved among all CAdV isolates by sequence alignment analysis. Thus, these results provide insights into the interaction between virus and mAbs at the aa level and may have potential applications in the development of novel therapeutic or epitope-based vaccines, antibody therapeutics and a diagnostic method suitable for the rapid detection of all CAdVs.
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Bulcha JT, Wang Y, Ma H, Tai PWL, Gao G. Viral vector platforms within the gene therapy landscape. Signal Transduct Target Ther 2021; 6:53. [PMID: 33558455 PMCID: PMC7868676 DOI: 10.1038/s41392-021-00487-6] [Citation(s) in RCA: 459] [Impact Index Per Article: 153.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/05/2020] [Accepted: 10/23/2020] [Indexed: 01/30/2023] Open
Abstract
Throughout its 40-year history, the field of gene therapy has been marked by many transitions. It has seen great strides in combating human disease, has given hope to patients and families with limited treatment options, but has also been subject to many setbacks. Treatment of patients with this class of investigational drugs has resulted in severe adverse effects and, even in rare cases, death. At the heart of this dichotomous field are the viral-based vectors, the delivery vehicles that have allowed researchers and clinicians to develop powerful drug platforms, and have radically changed the face of medicine. Within the past 5 years, the gene therapy field has seen a wave of drugs based on viral vectors that have gained regulatory approval that come in a variety of designs and purposes. These modalities range from vector-based cancer therapies, to treating monogenic diseases with life-altering outcomes. At present, the three key vector strategies are based on adenoviruses, adeno-associated viruses, and lentiviruses. They have led the way in preclinical and clinical successes in the past two decades. However, despite these successes, many challenges still limit these approaches from attaining their full potential. To review the viral vector-based gene therapy landscape, we focus on these three highly regarded vector platforms and describe mechanisms of action and their roles in treating human disease.
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Affiliation(s)
- Jote T Bulcha
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Yi Wang
- Department of Pathophysiology, West China College of Basic medical sciences & Forensic Medicine, Sichuan University, Chengdu, China
| | - Hong Ma
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Phillip W L Tai
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
- VIDE Program, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA.
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11
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Nemerow G, Flint J. Lessons learned from adenovirus (1970-2019). FEBS Lett 2019; 593:3395-3418. [PMID: 31777951 DOI: 10.1002/1873-3468.13700] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/24/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022]
Abstract
Animal viruses are well recognized for their ability to uncover fundamental cell and molecular processes, and adenovirus certainly provides a prime example. This review illustrates the lessons learned from studying adenovirus over the past five decades. We take a look back at the key studies of adenovirus structure and biophysical properties, which revealed the mechanisms of adenovirus association with antibody, cell receptor, and immune molecules that regulate infection. In addition, we discuss the critical contribution of studies of adenovirus gene expression to elucidation of fundamental reactions in pre-mRNA processing and its regulation. Other pioneering studies furnished the first examples of protein-primed initiation of DNA synthesis and viral small RNAs. As a nonenveloped virus, adenoviruses have furnished insights into the modes of virus attachment, entry, and penetration of host cells, and we discuss the diversity of cell receptors that support these processes, as well as membrane penetration. As a result of these extensive studies, adenovirus vectors were among the first to be developed for therapeutic applications. We highlight some of the early (unsuccessful) trials and the lessons learned from them.
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Affiliation(s)
- Glen Nemerow
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, USA
| | - Jane Flint
- Department of Molecular Biology, Princeton University, NJ, USA
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Abstract
Human adenovirus (HAdV) is a ubiquitous virus that infects the mucosa of the eye. It is the most common cause of infectious conjunctivitis worldwide, affecting people of all ages and demographics. Pharyngoconjunctival fever outbreak is due to HAdV types 3, 4, and 7, whereas outbreaks of epidemic keratoconjunctivitis are usually caused by HAdV types 8, 19, 37, and 54. Primary cellular receptors, such as CAR, CD46, and sialic acid interact with fiber-knob protein to mediate adenoviral attachment to the host cell, whereas adenoviral penton base–integrin interaction mediates internalization of adenovirus. Type 1 immunoresponse to adenoviral ocular infection involves both innate immunity mediated by natural killer cells and type 1 interferon, as well as adaptive immunity mediated mainly by CD8 T cells. The resulting ocular manifestations are widely variable, with pharyngoconjunctival fever being the most common, manifesting clinically with fever, pharyngitis, and follicular conjunctivitis. Epidemic keratoconjunctivitis, however, is the severest form, with additional involvement of the cornea leading to development of subepithelial infiltrates. Because there is currently no US Food and Drug Administration-approved treatment for adenoviral ocular infection, current management is palliative. The presence of sight-threatening complications following ocular adenoviral infection warrants the necessity for developing antiadenoviral therapy with enhanced therapeutic index. Future trends that focus on adenoviral pathogenesis, including adenoviral protein, which utilize host receptors to promote infection, could be potential therapeutic targets, yielding shorter active disease duration and reduced disease burden.
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Affiliation(s)
- DeGaulle I Chigbu
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA, USA,
| | - Bisant A Labib
- Pennsylvania College of Optometry, Salus University, Elkins Park, PA, USA,
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13
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Atomic Structures of Minor Proteins VI and VII in Human Adenovirus. J Virol 2017; 91:JVI.00850-17. [PMID: 28978703 DOI: 10.1128/jvi.00850-17] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 09/15/2017] [Indexed: 12/31/2022] Open
Abstract
Human adenoviruses (Ad) are double-stranded DNA (dsDNA) viruses associated with infectious diseases, but they are better known as tools for gene delivery and oncolytic anticancer therapy. Atomic structures of Ad provide the basis for the development of antivirals and for engineering efforts toward more effective applications. Since 2010, atomic models of human Ad5 have been derived independently from photographic film cryo-electron microscopy (cryo-EM) and X-ray crystallography studies, but discrepancies exist concerning the assignment of cement proteins IIIa, VIII, and IX. To clarify these discrepancies, we employed the technology of direct electron counting to obtain a cryo-EM structure of human Ad5 at 3.2-Å resolution. Our improved structure unambiguously confirms our previous cryo-EM models of proteins IIIa, VIII, and IX and explains the likely cause of conflict in the crystallography models. The improved structure also allows the identification of three new components in the cavity of hexon-the cleaved N terminus of precursor protein VI (pVIn), the cleaved N terminus of precursor protein VII (pVIIn2), and mature protein VI. The binding of pVIIn2-and, by extension, that of genome-condensing pVII-to hexons is consistent with the previously proposed dsDNA genome-capsid coassembly for adenoviruses, which resembles that of single-stranded RNA (ssRNA) viruses but differs from the well-established mechanism of pumping dsDNA into a preformed protein capsid exemplified by tailed bacteriophages and herpesviruses.IMPORTANCE Adenovirus is a double-edged sword to humans: it is a widespread pathogen but can be used as a bioengineering tool for anticancer and gene therapies. The atomic structure of the virus provides the basis for antiviral and application developments, but conflicting atomic models for the important cement proteins IIIa, VIII, and IX from conventional/film cryo-EM and X-ray crystallography studies have caused confusion. Using cutting-edge cryo-EM technology with electron counting, we improved the structure of human adenovirus type 5 and confirmed our previous models of cement proteins IIIa, VIII, and IX, thus clarifying the inconsistent structures. The improved structure also reveals atomic details of membrane-lytic protein VI and genome-condensing protein VII and supports the previously proposed genome-capsid coassembly mechanism for adenoviruses.
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Reddy VS. The Role of Hexon Protein as a Molecular Mold in Patterning the Protein IX Organization in Human Adenoviruses. J Mol Biol 2017; 429:2747-2751. [PMID: 28728980 DOI: 10.1016/j.jmb.2017.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/04/2017] [Accepted: 06/08/2017] [Indexed: 10/19/2022]
Abstract
Adenoviruses are respiratory, ocular and enteric pathogens that form complex capsids, which are assembled from seven different structural proteins and composed of several core proteins that closely interact with the packaged dsDNA genome. The recent near-atomic resolution structures revealed that the interlacing continuous hexagonal network formed by the protein IX molecules is conserved among different human adenoviruses (HAdVs), but not in non-HAdVs. In this report, we propose a distinct role for the hexon protein as a "molecular mold" in enabling the formation of such hexagonal protein IX network that has been shown to preserve the stability and infectivity of HAdVs.
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Affiliation(s)
- Vijay S Reddy
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.
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15
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Yu X, Veesler D, Campbell MG, Barry ME, Asturias FJ, Barry MA, Reddy VS. Cryo-EM structure of human adenovirus D26 reveals the conservation of structural organization among human adenoviruses. SCIENCE ADVANCES 2017; 3:e1602670. [PMID: 28508067 PMCID: PMC5425241 DOI: 10.1126/sciadv.1602670] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 03/09/2017] [Indexed: 05/17/2023]
Abstract
Human adenoviruses (HAdVs) cause acute respiratory, ocular, and gastroenteric diseases and are also frequently used as gene and vaccine delivery vectors. Unlike the archetype human adenovirus C5 (HAdV-C5), human adenovirus D26 (HAdV-D26) belongs to species-D HAdVs, which target different cellular receptors, and is differentially recognized by immune surveillance mechanisms. HAdV-D26 is being championed as a lower seroprevalent vaccine and oncolytic vector in preclinical and human clinical studies. To understand the molecular basis for their distinct biological properties and independently validate the structures of minor proteins, we determined the first structure of species-D HAdV at 3.7 Å resolution by cryo-electron microscopy. All the hexon hypervariable regions (HVRs), including HVR1, have been identified and exhibit a distinct organization compared to those of HAdV-C5. Despite the differences in the arrangement of helices in the coiled-coil structures, protein IX molecules form a continuous hexagonal network on the capsid exterior. In addition to the structurally conserved region (3 to 300) of IIIa, we identified an extra helical domain comprising residues 314 to 390 that further stabilizes the vertex region. Multiple (two to three) copies of the cleaved amino-terminal fragment of protein VI (pVIn) are observed in each hexon cavity, suggesting that there could be ≥480 copies of VI present in HAdV-D26. In addition, a localized asymmetric reconstruction of the vertex region provides new details of the three-pronged "claw hold" of the trimeric fiber and its interactions with the penton base. These observations resolve the previous conflicting assignments of the minor proteins and suggest the likely conservation of their organization across different HAdVs.
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Affiliation(s)
- Xiaodi Yu
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - David Veesler
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Melody G. Campbell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Mary E. Barry
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN 55902, USA
| | - Francisco J. Asturias
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael A. Barry
- Division of Infectious Diseases, Mayo Clinic, Rochester, MN 55902, USA
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55902, USA
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55902, USA
| | - Vijay S. Reddy
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- Corresponding author.
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16
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Shah MS, Ashraf A, Khan MI, Rahman M, Habib M, Chughtai MI, Qureshi JA. Fowl adenovirus: history, emergence, biology and development of a vaccine against hydropericardium syndrome. Arch Virol 2017; 162:1833-1843. [PMID: 28283816 DOI: 10.1007/s00705-017-3313-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 03/05/2017] [Indexed: 12/16/2022]
Abstract
The poultry industry has emerged as one of the largest and fastest growing public sectors in the developed and developing countries. Unfortunately, this industry is under a major threat from diseases that are viral (Newcastle disease, infectious bursal disease, influenza, hydropericardium syndrome), bacterial (colibacillosis, pasteurellosis, salmonellosis, mycoplasmosis), parasitic (coccidiosis, histoplasmosis) or nutritional (dyschondroplasia, osteoporosis). Among these diseases, hydropericardium syndrome (HPS) is one of the important emerging diseases occurring in the specific areas of the world where broilers (chickens) are reared under intensive conditions. HPS was first observed in 1987 at Angara Goth, an area near Karachi, Pakistan, where broilers are raised. Since then, HPS has been reported in many countries of the world. From these reported cases, an adenovirus that was either isolated from or visualized electron microscopically in the liver of affected broilers has been implicated in the syndrome. The syndrome has been reproduced by inoculation of isolated fowl adenovirus (FAdV) strains, and hence, the syndrome is also called infectious hydropericardium syndrome. To our knowledge, HPS has not been observed in humans, so it is not considered a zoonotic disease, but it is of economic importance and causes huge losses to the poultry industry. Efforts have been made to develop conventional vaccines against this disease, which were formulated from infected liver homogenate. Formalin-inactivated liver organ vaccines have failed to protect the poultry industry. Hence, there is a dire need to develop a suitable vaccine to combat this disease. Currently, recombinant vaccine candidates are being developed by using molecular biology and biotechnological approaches for the prevention and control of infectious diseases, including HPS. Therefore, it is suggested that the immunogenicity of these recombinant proteins should be evaluated for their use as subunit vaccines.
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Affiliation(s)
- M S Shah
- Department of Pathobiology and Veterinary Sciences, University of Connecticut, Storrs, USA.
- National Institute of Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan.
| | - A Ashraf
- Department of Zoology, G.C University, Faisalabad, Pakistan
| | - M I Khan
- Department of Pathobiology and Veterinary Sciences, University of Connecticut, Storrs, USA
| | - M Rahman
- National Institute of Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - M Habib
- Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan
| | - M I Chughtai
- Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan
| | - J A Qureshi
- National Institute of Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- University of Lahore, Defense Road, Lahore, Pakistan
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17
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Nemerow GR, Stewart PL. Insights into Adenovirus Uncoating from Interactions with Integrins and Mediators of Host Immunity. Viruses 2016; 8:v8120337. [PMID: 28009821 PMCID: PMC5192398 DOI: 10.3390/v8120337] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/15/2016] [Accepted: 12/16/2016] [Indexed: 01/28/2023] Open
Abstract
Human adenoviruses are large (150 MDa) nonenveloped double-stranded DNA (dsDNA) viruses that cause acute respiratory, gastrointestinal and ocular infections. Despite these disease associations, adenovirus has aided basic and clinical research efforts through studies of its association with cells and as a target of host antiviral responses. This review highlights the knowledge of adenovirus disassembly and nuclear transport gleaned from structural, biophysical and functional analyses of adenovirus interactions with soluble and membrane-associated host molecules.
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Affiliation(s)
- Glen R Nemerow
- Department of Immunology and Microbial Science the Scripps Research Institute, La Jolla, CA 92037, USA.
| | - Phoebe L Stewart
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, OH 44106, USA.
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18
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Zhang C, Zhou D. Adenoviral vector-based strategies against infectious disease and cancer. Hum Vaccin Immunother 2016; 12:2064-2074. [PMID: 27105067 PMCID: PMC4994731 DOI: 10.1080/21645515.2016.1165908] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Adenoviral vectors are widely employed against infectious diseases or cancers, as they can elicit specific antibody responses and T cell responses when they are armed with foreign genes as vaccine carriers, and induce apoptosis of the cancer cells when they are genetically modified for cancer therapy. In this review, we summarize the biological characteristics of adenovirus (Ad) and the latest development of Ad vector-based strategies for the prevention and control of emerging infectious diseases or cancers. Strategies to circumvent the pre-existing neutralizing antibodies which dampen the immunogenicity of Ad-based vaccines are also discussed.
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Affiliation(s)
- Chao Zhang
- a Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences , Shanghai , China
| | - Dongming Zhou
- a Vaccine Research Center, Key Laboratory of Molecular Virology & Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences , Shanghai , China
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19
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Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) gene was identified in 1989. This opened the door for the development of cystic fibrosis (CF) gene therapy, which has been actively pursued for the last 20 years. Although 26 clinical trials involving approximately 450 patients have been carried out, the vast majority of these trials were short and included small numbers of patients; they were not designed to assess clinical benefit, but to establish safety and proof-of-concept for gene transfer using molecular end points such as the detection of recombinant mRNA or correction of the ion transport defect. The only currently published trial designed and powered to assess clinical efficacy (defined as improvement in lung function) administered AAV2-CFTR to the lungs of patients with CF. The U.K. Cystic Fibrosis Gene Therapy Consortium completed, in the autumn of 2014, the first nonviral gene therapy trial designed to answer whether repeated nonviral gene transfer (12 doses over 12 months) can lead to clinical benefit. The demonstration that the molecular defect in CFTR can be corrected with small-molecule drugs, and the success of gene therapy in other monogenic diseases, is boosting interest in CF gene therapy. Developments are discussed here.
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Affiliation(s)
- Uta Griesenbach
- Department of Gene Therapy and the U.K. Cystic Fibrosis Gene Therapy Consortium, Imperial College, London SW3 6LR, United Kingdom
| | - Kamila M Pytel
- Department of Gene Therapy and the U.K. Cystic Fibrosis Gene Therapy Consortium, Imperial College, London SW3 6LR, United Kingdom
| | - Eric W F W Alton
- Department of Gene Therapy and the U.K. Cystic Fibrosis Gene Therapy Consortium, Imperial College, London SW3 6LR, United Kingdom
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20
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Veesler D, Kearney BM, Johnson JE. Integration of X-ray crystallography and electron cryo-microscopy in the analysis of virus structure and function. CRYSTALLOGR REV 2015. [DOI: 10.1080/0889311x.2015.1038530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Condezo GN, Marabini R, Ayora S, Carazo JM, Alba R, Chillón M, San Martín C. Structures of Adenovirus Incomplete Particles Clarify Capsid Architecture and Show Maturation Changes of Packaging Protein L1 52/55k. J Virol 2015; 89:9653-64. [PMID: 26178997 PMCID: PMC4542391 DOI: 10.1128/jvi.01453-15] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/07/2015] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Adenovirus is one of the most complex icosahedral, nonenveloped viruses. Even after its structure was solved at near-atomic resolution by both cryo-electron microscopy and X-ray crystallography, the location of minor coat proteins is still a subject of debate. The elaborated capsid architecture is the product of a correspondingly complex assembly process, about which many aspects remain unknown. Genome encapsidation involves the concerted action of five virus proteins, and proteolytic processing by the virus protease is needed to prime the virion for sequential uncoating. Protein L1 52/55k is required for packaging, and multiple cleavages by the maturation protease facilitate its release from the nascent virion. Light-density particles are routinely produced in adenovirus infections and are thought to represent assembly intermediates. Here, we present the molecular and structural characterization of two different types of human adenovirus light particles produced by a mutant with delayed packaging. We show that these particles lack core polypeptide V but do not lack the density corresponding to this protein in the X-ray structure, thereby adding support to the adenovirus cryo-electron microscopy model. The two types of light particles present different degrees of proteolytic processing. Their structures provide the first glimpse of the organization of L1 52/55k protein inside the capsid shell and of how this organization changes upon partial maturation. Immature, full-length L1 52/55k is poised beneath the vertices to engage the virus genome. Upon proteolytic processing, L1 52/55k disengages from the capsid shell, facilitating genome release during uncoating. IMPORTANCE Adenoviruses have been extensively characterized as experimental systems in molecular biology, as human pathogens, and as therapeutic vectors. However, a clear picture of many aspects of their basic biology is still lacking. Two of these aspects are the location of minor coat proteins in the capsid and the molecular details of capsid assembly. Here, we provide evidence supporting one of the two current models for capsid architecture. We also show for the first time the location of the packaging protein L1 52/55k in particles lacking the virus genome and how this location changes during maturation. Our results contribute to clarifying standing questions in adenovirus capsid architecture and provide new details on the role of L1 52/55k protein in assembly.
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Affiliation(s)
- Gabriela N Condezo
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, CSIC, Madrid, Spain NanoBiomedicine Initiative, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Roberto Marabini
- Escuela Politécnica Superior, Universidad Autónoma de Madrid, Madrid, Spain
| | - Silvia Ayora
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - José M Carazo
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
| | - Raúl Alba
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain Center of Animal Biotechnology and Gene Therapy, Departament Bioquímica i Biologia Molecular, Universitat Autònoma Barcelona, Bellaterra, Spain
| | - Miguel Chillón
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain Center of Animal Biotechnology and Gene Therapy, Departament Bioquímica i Biologia Molecular, Universitat Autònoma Barcelona, Bellaterra, Spain
| | - Carmen San Martín
- Department of Macromolecular Structures, Centro Nacional de Biotecnología, CSIC, Madrid, Spain NanoBiomedicine Initiative, Centro Nacional de Biotecnología, CSIC, Madrid, Spain
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22
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Wiethoff CM, Nemerow GR. Adenovirus membrane penetration: Tickling the tail of a sleeping dragon. Virology 2015; 479-480:591-9. [PMID: 25798531 DOI: 10.1016/j.virol.2015.03.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 02/18/2015] [Accepted: 03/03/2015] [Indexed: 11/19/2022]
Abstract
As is the case for nearly every viral pathogen, non-enveloped viruses (NEV) must maintain their integrity under potentially harsh environmental conditions while retaining the ability to undergo rapid disassembly at the right time and right place inside host cells. NEVs generally exist in this metastable state until they encounter key cellular stimuli such as membrane receptors, decreased intracellular pH, digestion by cellular proteases, or a combination of these factors. These stimuli trigger conformational changes in the viral capsid that exposes a sequestered membrane-perturbing protein. This protein subsequently modifies the cell membrane in such a way as to allow passage of the virion and accompanying nucleic acid payload into the cell cytoplasm. Different NEVs employ variations of this general pathway for cell entry (Moyer and Nemerow, 2011, Curr. Opin. Virol., 1, 44-49), however this review will focus on significant new knowledge obtained on cell entry by human adenovirus (HAdV).
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Affiliation(s)
| | - Glen R Nemerow
- The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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The amphipathic helix of adenovirus capsid protein VI contributes to penton release and postentry sorting. J Virol 2014; 89:2121-35. [PMID: 25473051 DOI: 10.1128/jvi.02257-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Nuclear delivery of the adenoviral genome requires that the capsid cross the limiting membrane of the endocytic compartment and traverse the cytosol to reach the nucleus. This endosomal escape is initiated upon internalization and involves a highly coordinated process of partial disassembly of the entering capsid to release the membrane lytic internal capsid protein VI. Using wild-type and protein VI-mutated human adenovirus serotype 5 (HAdV-C5), we show that capsid stability and membrane rupture are major determinants of entry-related sorting of incoming adenovirus virions. Furthermore, by using electron cryomicroscopy, as well as penton- and protein VI-specific antibodies, we show that the amphipathic helix of protein VI contributes to capsid stability by preventing premature disassembly and deployment of pentons and protein VI. Thus, the helix has a dual function in maintaining the metastable state of the capsid by preventing premature disassembly and mediating efficient membrane lysis to evade lysosomal targeting. Based on these findings and structural data from cryo-electron microscopy, we suggest a refined disassembly mechanism upon entry. IMPORTANCE In this study, we show the intricate connection of adenovirus particle stability and the entry-dependent release of the membrane-lytic capsid protein VI required for endosomal escape. We show that the amphipathic helix of the adenovirus internal protein VI is required to stabilize pentons in the particle while coinciding with penton release upon entry and that release of protein VI mediates membrane lysis, thereby preventing lysosomal sorting. We suggest that this dual functionality of protein VI ensures an optimal disassembly process by balancing the metastable state of the mature adenovirus particle.
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Mangel WF, San Martín C. Structure, function and dynamics in adenovirus maturation. Viruses 2014; 6:4536-70. [PMID: 25421887 PMCID: PMC4246237 DOI: 10.3390/v6114536] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/10/2014] [Accepted: 11/17/2014] [Indexed: 01/18/2023] Open
Abstract
Here we review the current knowledge on maturation of adenovirus, a non-enveloped icosahedral eukaryotic virus. The adenovirus dsDNA genome fills the capsid in complex with a large amount of histone-like viral proteins, forming the core. Maturation involves proteolytic cleavage of several capsid and core precursor proteins by the viral protease (AVP). AVP uses a peptide cleaved from one of its targets as a "molecular sled" to slide on the viral genome and reach its substrates, in a remarkable example of one-dimensional chemistry. Immature adenovirus containing the precursor proteins lacks infectivity because of its inability to uncoat. The immature core is more compact and stable than the mature one, due to the condensing action of unprocessed core polypeptides; shell precursors underpin the vertex region and the connections between capsid and core. Maturation makes the virion metastable, priming it for stepwise uncoating by facilitating vertex release and loosening the condensed genome and its attachment to the icosahedral shell. The packaging scaffold protein L1 52/55k is also a substrate for AVP. Proteolytic processing of L1 52/55k disrupts its interactions with other virion components, providing a mechanism for its removal during maturation. Finally, possible roles for maturation of the terminal protein are discussed.
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Affiliation(s)
- Walter F Mangel
- Biological, Environmental and Climate Sciences Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
| | - Carmen San Martín
- Department of Macromolecular Structure and NanoBiomedicine Initiative, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, Madrid 28049, Spain.
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25
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The adenovirus genome contributes to the structural stability of the virion. Viruses 2014; 6:3563-83. [PMID: 25254384 PMCID: PMC4189039 DOI: 10.3390/v6093563] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 11/17/2022] Open
Abstract
Adenovirus (Ad) vectors are currently the most commonly used platform for therapeutic gene delivery in human gene therapy clinical trials. Although these vectors are effective, many researchers seek to further improve the safety and efficacy of Ad-based vectors through detailed characterization of basic Ad biology relevant to its function as a vector system. Most Ad vectors are deleted of key, or all, viral protein coding sequences, which functions to not only prevent virus replication but also increase the cloning capacity of the vector for foreign DNA. However, radical modifications to the genome size significantly decreases virion stability, suggesting that the virus genome plays a role in maintaining the physical stability of the Ad virion. Indeed, a similar relationship between genome size and virion stability has been noted for many viruses. This review discusses the impact of the genome size on Ad virion stability and emphasizes the need to consider this aspect of virus biology in Ad-based vector design.
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Structures and organization of adenovirus cement proteins provide insights into the role of capsid maturation in virus entry and infection. Proc Natl Acad Sci U S A 2014; 111:11715-20. [PMID: 25071205 DOI: 10.1073/pnas.1408462111] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Adenovirus cement proteins play crucial roles in virion assembly, disassembly, cell entry, and infection. Based on a refined crystal structure of the adenovirus virion at 3.8-Å resolution, we have determined the structures of all of the cement proteins (IIIa, VI, VIII, and IX) and their organization in two distinct layers. We have significantly revised the recent cryoelectron microscopy models for proteins IIIa and IX and show that both are located on the capsid exterior. Together, the cement proteins exclusively stabilize the hexon shell, thus rendering penton vertices the weakest links of the adenovirus capsid. We describe, for the first time to our knowledge, the structure of protein VI, a key membrane-lytic molecule, and unveil its associations with VIII and core protein V, which together glue peripentonal hexons beneath the vertex region and connect them to the rest of the capsid on the interior. Following virion maturation, the cleaved N-terminal propeptide of VI is observed, reaching deep into the peripentonal hexon cavity, detached from the membrane-lytic domain, so that the latter can be released. Our results thus provide the molecular basis for the requirement of maturation cleavage of protein VI. This process is essential for untethering and release of the membrane-lytic region, which is known to mediate endosome rupture and delivery of partially disassembled virions into the host cell cytoplasm.
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27
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Majhen D, Calderon H, Chandra N, Fajardo CA, Rajan A, Alemany R, Custers J. Adenovirus-based vaccines for fighting infectious diseases and cancer: progress in the field. Hum Gene Ther 2014; 25:301-17. [PMID: 24580050 DOI: 10.1089/hum.2013.235] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The field of adenovirology is undergoing rapid change in response to increasing appreciation of the potential advantages of adenoviruses as the basis for new vaccines and as vectors for gene and cancer therapy. Substantial knowledge and understanding of adenoviruses at a molecular level has made their manipulation for use as vaccines and therapeutics relatively straightforward in comparison with other viral vectors. In this review we summarize the structure and life cycle of the adenovirus and focus on the use of adenovirus-based vectors in vaccines against infectious diseases and cancers. Strategies to overcome the problem of preexisting antiadenovirus immunity, which can hamper the immunogenicity of adenovirus-based vaccines, are discussed. When armed with tumor-associated antigens, replication-deficient and oncolytic adenoviruses can efficiently activate an antitumor immune response. We present concepts on how to use adenoviruses as therapeutic cancer vaccines and consider some of the strategies used to further improve antitumor immune responses. Studies that explore the prospect of adenoviruses as vaccines against infectious diseases and cancer are underway, and here we give an overview of the latest developments.
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28
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Cheng L, Huang X, Li X, Xiong W, Sun W, Yang C, Zhang K, Wang Y, Liu H, Huang X, Ji G, Sun F, Zheng C, Zhu P. Cryo-EM structures of two bovine adenovirus type 3 intermediates. Virology 2014; 450-451:174-81. [PMID: 24503080 DOI: 10.1016/j.virol.2013.12.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 10/04/2013] [Accepted: 12/10/2013] [Indexed: 01/28/2023]
Abstract
Adenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level.
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Affiliation(s)
- Lingpeng Cheng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaoxing Huang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaomin Li
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei Xiong
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072, China
| | - Wei Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Chongwen Yang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Kai Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ying Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongrong Liu
- College of Physics and Information Science, Hunan Normal University, Changsha, Hunan 410081, China
| | - Xiaojun Huang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Gang Ji
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Congyi Zheng
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072, China.
| | - Ping Zhu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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Identification of a suppressor mutation that improves the yields of hexon-modified adenovirus vectors. J Virol 2013; 87:9661-71. [PMID: 23824800 DOI: 10.1128/jvi.00462-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have generated hexon-modified adenovirus serotype 5 (Ad5) vectors that are not neutralized by Ad5-specific neutralizing antibodies in mice. These vectors are attractive for the advancement of vaccine products because of their potential for inducing robust antigen-specific immune responses in people with prior exposure to Ad5. However, hexon-modified Ad5 vectors displayed an approximate 10-fold growth defect in complementing cells, making potential vaccine costs unacceptably high. Replacing hypervariable regions (HVRs) 1, 2, 4, and 5 with the equivalent HVRs from Ad43 was sufficient to avoid Ad5 preexisting immunity and retain full vaccine potential. However, the resulting vector displayed the same growth defect as the hexon-modified vector carrying all 9 HVRs from Ad43. The growth defect is likely due to a defect in capsid assembly, since DNA replication and late protein accumulation were normal in these vectors. We determined that the hexon-modified vectors have a 32°C cold-sensitive phenotype and selected revertants that restored vector productivity. Genome sequencing identified a single base change resulting in a threonine-to-methionine amino acid substitution at the position equivalent to residue 342 of the wild-type protein. This mutation has a suppressor phenotype (SP), since cloning it into our Ad5 vector containing all nine hypervariable regions from Ad43, Ad5.H(43m-43), increased yields over the version without the SP mutation. This growth improvement was also shown for an Ad5-based hexon-modified vector that carried the hexon hypervariable regions of Ad48, indicating that the SP mutation may have broad applicability for improving the productivity of different hexon-modified vectors.
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Coagulation factor binding orientation and dimerization may influence infectivity of adenovirus-coagulation factor complexes. J Virol 2013; 87:9610-9. [PMID: 23804638 DOI: 10.1128/jvi.01070-13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Adenoviruses (Ads) are promising vectors for therapeutic interventions in humans. When injected into the bloodstream, Ad vectors can bind several vitamin K-dependent blood coagulation factors, which contributes to virus sequestration in the liver by facilitating transduction of hepatocytes. Although both coagulation factors FVII and FX bind the hexon protein of human Ad serotype 5 (HAdv5) with a very high affinity, only FX appears to play a role in mediating Ad-hepatocyte transduction in vivo. To understand the discrepancy between efficacy of FVII binding to hexon and its apparently poor capacity for supporting virus cell entry, we analyzed the HAdv5-FVII complex by using high-resolution cryo-electron microscopy (cryo-EM) followed by molecular dynamic flexible fitting (MDFF) simulations. The results indicate that although hexon amino acids T423, E424, and T425, identified earlier as critical for FX binding, are also involved in mediating binding of FVII, the FVII GLA domain sits within the surface-exposed hexon trimer depression in a different orientation from that found for FX. Furthermore, we found that when bound to hexon, two proximal FVII molecules interact via their serine protease (SP) domains and bury potential heparan sulfate proteoglycan (HSPG) receptor binding residues within the dimer interface. In contrast, earlier cryo-EM studies of the Ad-FX interaction showed no evidence of dimer formation. Dimerization of FVII bound to Ad may be a contributing mechanistic factor for the differential infectivity of Ad-FX and Ad-FVII complexes, despite high-affinity binding of both these coagulation factors to the virus.
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31
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Flatt JW, Kim R, Smith JG, Nemerow GR, Stewart PL. An intrinsically disordered region of the adenovirus capsid is implicated in neutralization by human alpha defensin 5. PLoS One 2013; 8:e61571. [PMID: 23620768 PMCID: PMC3631211 DOI: 10.1371/journal.pone.0061571] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 03/10/2013] [Indexed: 11/18/2022] Open
Abstract
Human α-defensins are proteins of the innate immune system that suppress viral and bacterial infections by multiple mechanisms including membrane disruption. For viruses that lack envelopes, such as human adenovirus (HAdV), other, less well defined, mechanisms must be involved. A previous structural study on the interaction of an α-defensin, human α-defensin 5 (HD5), with HAdV led to a proposed mechanism in which HD5 stabilizes the vertex region of the capsid and blocks uncoating steps required for infectivity. Studies with virus chimeras comprised of capsid proteins from sensitive and resistant serotypes supported this model. To further characterize the critical binding site, we determined subnanometer resolution cryo-electron microscopy (cryoEM) structures of HD5 complexed with both neutralization-sensitive and -resistant HAdV chimeras. Models were built for the vertex regions of these chimeras with monomeric and dimeric forms of HD5 in various initial orientations. CryoEM guided molecular dynamics flexible fitting (MDFF) was used to restrain the majority of the vertex model in well-defined cryoEM density. The RGD-containing penton base loops of both the sensitive and resistant virus chimeras are predicted to be intrinsically disordered, and little cryoEM density is observed for them. In simulations these loops from the sensitive virus chimera, interact with HD5, bridge the penton base and fiber proteins, and provides significant stabilization with a three-fold increase in the intermolecular nonbonded interactions of the vertex complex. In the case of the resistant virus chimera, simulations revealed fewer bridging interactions and reduced stabilization by HD5. This study implicates a key dynamic region in mediating a stabilizing interaction between a viral capsid and a protein of the innate immune system with potent anti-viral activity.
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Affiliation(s)
- Justin W. Flatt
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Robert Kim
- Department of Molecular Physiology and Biophysics, School of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jason G. Smith
- Department of Microbiology, University of Washington, Seattle, Washington, United States of America
| | - Glen R. Nemerow
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, United States of America
| | - Phoebe L. Stewart
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Abstract
Cancer gene therapy approaches have benefited greatly from the utilization of molecular-based therapeutics. Of these, adenovirus-based interventions hold much promise as a platform for targeted therapeutic delivery to tumors. However, a barrier to this progression is the lack of native adenovirus receptor expression on a variety of cancer types. As such, any adenovirus-based cancer therapy must take into consideration retargeting the vector to nonnative cellular surface receptors. Predicated upon the knowledge gained in native adenovirus biology, several strategies to transductionally retarget adenovirus have emerged. Herein, we describe the biological hurdles as well as strategies utilized in adenovirus transductional targeting, covering the progress of both adapter-based and genetic manipulation-based targeting. Additionally, we discuss recent translation of these targeting strategies into a clinical setting.
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Affiliation(s)
- Matthew S Beatty
- Division of Cancer Biology, Department of Radiation Oncology, Washington University School of Medicine in St Louis, St Louis, Missouri, USA
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33
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Graziano V, McGrath WJ, Suomalainen M, Greber UF, Freimuth P, Blainey PC, Luo G, Xie XS, Mangel WF. Regulation of a viral proteinase by a peptide and DNA in one-dimensional space: I. binding to DNA AND to hexon of the precursor to protein VI, pVI, of human adenovirus. J Biol Chem 2013; 288:2059-67. [PMID: 23043136 PMCID: PMC3548512 DOI: 10.1074/jbc.m112.377150] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 08/02/2012] [Indexed: 11/06/2022] Open
Abstract
The precursor to adenovirus protein VI, pVI, is a multifunctional protein with different roles early and late in virus infection. Here, we focus on two roles late in infection, binding of pVI to DNA and to the major capsid protein hexon. pVI bound to DNA as a monomer independent of DNA sequence with an apparent equilibrium dissociation constant, K(d)((app)), of 46 nm. Bound to double-stranded DNA, one molecule of pVI occluded 8 bp. Upon the binding of pVI to DNA, three sodium ions were displaced from the DNA. A ΔG(0)(0) of -4.54 kcal/mol for the nonelectrostatic free energy of binding indicated that a substantial component of the binding free energy resulted from nonspecific interactions between pVI and DNA. The proteolytically processed, mature form of pVI, protein VI, also bound to DNA; its K(d)((app)) was much higher, 307 nm. The binding assays were performed in 1 mm MgCl(2) because in the absence of magnesium, the binding to pVI or protein VI to DNA was too tight to determine a K(d)((app)). Three molecules of pVI bound to one molecule of the hexon trimer with an equilibrium dissociation constant K(d)((app)) of 1.1 nm.
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Affiliation(s)
- Vito Graziano
- From the Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - William J. McGrath
- From the Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Maarit Suomalainen
- the Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland, and
| | - Urs F. Greber
- the Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland, and
| | - Paul Freimuth
- From the Biology Department, Brookhaven National Laboratory, Upton, New York 11973
| | - Paul C. Blainey
- the Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Guobin Luo
- the Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - X. Sunney Xie
- the Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Walter F. Mangel
- From the Biology Department, Brookhaven National Laboratory, Upton, New York 11973
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34
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Woetzel N, Karakaş M, Staritzbichler R, Müller R, Weiner BE, Meiler J. BCL::Score--knowledge based energy potentials for ranking protein models represented by idealized secondary structure elements. PLoS One 2012; 7:e49242. [PMID: 23173051 PMCID: PMC3500277 DOI: 10.1371/journal.pone.0049242] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 10/07/2012] [Indexed: 11/20/2022] Open
Abstract
The topology of most experimentally determined protein domains is defined by the relative arrangement of secondary structure elements, i.e. α-helices and β-strands, which make up 50–70% of the sequence. Pairing of β-strands defines the topology of β-sheets. The packing of side chains between α-helices and β-sheets defines the majority of the protein core. Often, limited experimental datasets restrain the position of secondary structure elements while lacking detail with respect to loop or side chain conformation. At the same time the regular structure and reduced flexibility of secondary structure elements make these interactions more predictable when compared to flexible loops and side chains. To determine the topology of the protein in such settings, we introduce a tailored knowledge-based energy function that evaluates arrangement of secondary structure elements only. Based on the amino acid Cβ atom coordinates within secondary structure elements, potentials for amino acid pair distance, amino acid environment, secondary structure element packing, β-strand pairing, loop length, radius of gyration, contact order and secondary structure prediction agreement are defined. Separate penalty functions exclude conformations with clashes between amino acids or secondary structure elements and loops that cannot be closed. Each individual term discriminates for native-like protein structures. The composite potential significantly enriches for native-like models in three different databases of 10,000–12,000 protein models in 80–94% of the cases. The corresponding application, “BCL::ScoreProtein,” is available at www.meilerlab.org.
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Affiliation(s)
- Nils Woetzel
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Mert Karakaş
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Rene Staritzbichler
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Ralf Müller
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Brian E. Weiner
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jens Meiler
- Department of Chemistry, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail: * E-mail:
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35
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Flatt JW, Fox TL, Makarova N, Blackwell JL, Dmitriev IP, Kashentseva EA, Curiel DT, Stewart PL. CryoEM visualization of an adenovirus capsid-incorporated HIV antigen. PLoS One 2012; 7:e49607. [PMID: 23166728 PMCID: PMC3498208 DOI: 10.1371/journal.pone.0049607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 10/11/2012] [Indexed: 01/12/2023] Open
Abstract
Adenoviral (Ad) vectors show promise as platforms for vaccine applications against infectious diseases including HIV. However, the requirements for eliciting protective neutralizing antibody and cellular immune responses against HIV remain a major challenge. In a novel approach to generate 2F5- and 4E10-like antibodies, we engineered an Ad vector with the HIV membrane proximal ectodomain region (MPER) epitope displayed on the hypervariable region 2 (HVR2) of the viral hexon capsid, instead of expressed as a transgene. The structure and flexibility of MPER epitopes, and the structural context of these epitopes within viral vectors, play important roles in the induced host immune responses. In this regard, understanding the critical factors for epitope presentation would facilitate optimization strategies for developing viral vaccine vectors. Therefore we undertook a cryoEM structural study of this Ad vector, which was previously shown to elicit MPER-specific humoral immune responses. A subnanometer resolution cryoEM structure was analyzed with guided molecular dynamics simulations. Due to the arrangement of hexons within the Ad capsid, there are twelve unique environments for the inserted peptide that lead to a variety of conformations for MPER, including individual α-helices, interacting α-helices, and partially extended forms. This finding is consistent with the known conformational flexibility of MPER. The presence of an extended form, or an induced extended form, is supported by interaction of this vector with the human HIV monoclonal antibody 2F5, which recognizes 14 extended amino acids within MPER. These results demonstrate that the Ad capsid influences epitope structure, flexibility and accessibility, all of which affect the host immune response. In summary, this cryoEM structural study provided a means to visualize an epitope presented on an engineered viral vector and suggested modifications for the next generation of Ad vectors with capsid-incorporated HIV epitopes.
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Affiliation(s)
- Justin W. Flatt
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Tara L. Fox
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Natalia Makarova
- Department of Medicine, Division of Infectious Diseases, Emory Vaccine Center and Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Jerry L. Blackwell
- Department of Medicine, Division of Infectious Diseases, Emory Vaccine Center and Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, United States of America
| | - Igor P. Dmitriev
- Division of Cancer Biology, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Elena A. Kashentseva
- Division of Cancer Biology, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - David T. Curiel
- Division of Cancer Biology, Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Phoebe L. Stewart
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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36
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Conserved fiber-penton base interaction revealed by nearly atomic resolution cryo-electron microscopy of the structure of adenovirus provides insight into receptor interaction. J Virol 2012; 86:12322-9. [PMID: 22951835 DOI: 10.1128/jvi.01608-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Adenovirus (Ad) cell attachment is initiated by the attachment of the fiber protein to a primary receptor (usually CAR or CD46). This event is followed by the engagement of the penton base protein with a secondary receptor (integrin) via its loop region, which contains an Arg-Gly-Asp (RGD) motif, to trigger virus internalization. To understand the well-orchestrated adenovirus cell attachment process that involves the fiber and the penton base, we reconstructed the structure of an Ad5F35 capsid, comprising an adenovirus type 5 (Ad5) capsid pseudotyped with an Ad35 fiber, at a resolution of approximately 4.2 Å. The fiber-penton base interaction in the cryo-electron microscopic (cryo-EM) structure of Ad5F35 is similar to that in the cryo-EM structure of Ad5, indicating that the fiber-penton base interaction of adenovirus is conserved. Our structure also confirms that the C-terminal segment of the fiber tail domain constitutes the bottom trunk of the fiber shaft. Based on the conserved fiber-penton base interaction, we have proposed a model for the interaction of Ad5F35 with its primary and secondary receptors. This model could provide insight for designing adenovirus gene delivery vectors.
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37
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Lindert S, Alexander N, Wötzel N, Karakaş M, Stewart PL, Meiler J. EM-fold: de novo atomic-detail protein structure determination from medium-resolution density maps. Structure 2012; 20:464-78. [PMID: 22405005 DOI: 10.1016/j.str.2012.01.023] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 01/23/2012] [Accepted: 01/26/2012] [Indexed: 11/17/2022]
Abstract
Electron density maps of membrane proteins or large macromolecular complexes are frequently only determined at medium resolution between 4 Å and 10 Å, either by cryo-electron microscopy or X-ray crystallography. In these density maps, the general arrangement of secondary structure elements (SSEs) is revealed, whereas their directionality and connectivity remain elusive. We demonstrate that the topology of proteins with up to 250 amino acids can be determined from such density maps when combined with a computational protein folding protocol. Furthermore, we accurately reconstruct atomic detail in loop regions and amino acid side chains not visible in the experimental data. The EM-Fold algorithm assembles the SSEs de novo before atomic detail is added using Rosetta. In a benchmark of 27 proteins, the protocol consistently and reproducibly achieves models with root mean square deviation values <3 Å.
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Affiliation(s)
- Steffen Lindert
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, TN 37212, USA
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38
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San Martín C. Latest insights on adenovirus structure and assembly. Viruses 2012; 4:847-77. [PMID: 22754652 PMCID: PMC3386624 DOI: 10.3390/v4050847] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/11/2012] [Indexed: 01/06/2023] Open
Abstract
Adenovirus (AdV) capsid organization is considerably complex, not only because of its large size (~950 Å) and triangulation number (pseudo T = 25), but also because it contains four types of minor proteins in specialized locations modulating the quasi-equivalent icosahedral interactions. Up until 2009, only its major components (hexon, penton, and fiber) had separately been described in atomic detail. Their relationships within the virion, and the location of minor coat proteins, were inferred from combining the known crystal structures with increasingly more detailed cryo-electron microscopy (cryoEM) maps. There was no structural information on assembly intermediates. Later on that year, two reports described the structural differences between the mature and immature adenoviral particle, starting to shed light on the different stages of viral assembly, and giving further insights into the roles of core and minor coat proteins during morphogenesis [1,2]. Finally, in 2010, two papers describing the atomic resolution structure of the complete virion appeared [3,4]. These reports represent a veritable tour de force for two structural biology techniques: X-ray crystallography and cryoEM, as this is the largest macromolecular complex solved at high resolution by either of them. In particular, the cryoEM analysis provided an unprecedented clear picture of the complex protein networks shaping the icosahedral shell. Here I review these latest developments in the field of AdV structural studies.
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Affiliation(s)
- Carmen San Martín
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
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39
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Disulfide-bond formation by a single cysteine mutation in adenovirus protein VI impairs capsid release and membrane lysis. Virology 2012; 428:41-7. [PMID: 22516138 DOI: 10.1016/j.virol.2012.03.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 03/15/2012] [Accepted: 03/30/2012] [Indexed: 11/21/2022]
Abstract
The internal capsid protein VI mediates adenovirus (AdV) endosome penetration during cell entry. Essential to this process is the release of protein VI from the AdV capsid and subsequent membrane targeting and insertion by the liberated VI molecules within the endocytic vesicle. In this study, we describe a human AdV (HAdV) substitution mutant (AdV VI-G48C) within the critical N-terminal amphipathic α-helical domain of protein VI. The VI-G48C virus displays altered capsid stability that impacts protein VI release, membrane disruption and virus infectivity. This is due in part to aberrant disulfide-bonding of protein VI molecules within the AdV particle. Our results provide insight into the structural organization of protein VI in the virus particle, as well as highlight the role of protein VI in cell entry.
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40
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Sundquist WI, Krug RM. Assemble, replicate, remodel and evade. Curr Opin Virol 2012; 2:111-4. [DOI: 10.1016/j.coviro.2012.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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41
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Nemerow GR, Stewart PL, Reddy VS. Structure of human adenovirus. Curr Opin Virol 2012; 2:115-21. [PMID: 22482707 DOI: 10.1016/j.coviro.2011.12.008] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 12/23/2011] [Indexed: 10/14/2022]
Abstract
A detailed structural analysis of the entire human adenovirus capsid has been stymied by the complexity and size of this 150 MDa macromolecular complex. Over the past 10 years, the steady improvements in viral genome manipulation concomitant with advances in crystallographic techniques and data processing software has allowed structure determination of this virus by X-ray diffraction at 3.5 Å resolution. The virus structure revealed the location, folds, and interactions of major and minor (cement proteins) on the inner and outer capsid surface. This new structural information sheds further light on the process of adenovirus capsid assembly and virus-host cell interactions.
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Affiliation(s)
- Glen R Nemerow
- The Scripps Research Institute, La Jolla, CA 92037, United States.
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42
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Rossmann MG, Rao VB. Principles of virus structural organization. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 726:17-47. [PMID: 22297509 PMCID: PMC3767311 DOI: 10.1007/978-1-4614-0980-9_3] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Viruses, the molecular nanomachines infecting hosts ranging from prokaryotes to eukaryotes, come in different sizes, shapes, and symmetries. Questions such as what principles govern their structural organization, what factors guide their assembly, how these viruses integrate multifarious functions into one unique structure have enamored researchers for years. In the last five decades, following Caspar and Klug's elegant conceptualization of how viruses are constructed, high-resolution structural studies using X-ray crystallography and more recently cryo-EM techniques have provided a wealth of information on structures of a variety of viruses. These studies have significantly -furthered our understanding of the principles that underlie structural organization in viruses. Such an understanding has practical impact in providing a rational basis for the design and development of antiviral strategies. In this chapter, we review principles underlying capsid formation in a variety of viruses, emphasizing the recent developments along with some historical perspective.
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Affiliation(s)
- Michael G. Rossmann
- grid.169077.e0000000419372197Dept. Biological Sciences, Purdue University, W. State St. 915, West Lafayette, 47907-2054 Indiana USA
| | - Venigalla B. Rao
- grid.39936.360000000121746686Dept. Biology, Catholic University of America, Washington, 20064 District of Columbia USA
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43
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Henaff D, Salinas S, Kremer EJ. An adenovirus traffic update: from receptor engagement to the nuclear pore. Future Microbiol 2011; 6:179-92. [PMID: 21366418 DOI: 10.2217/fmb.10.162] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Adenoviruses have a bipolar nature: they are ubiquitous pathogens that occasionally cause life-threatening diseases or they can be engineered into powerful gene transfer vectors. The goal of this article is to summarize the most recent advances in adenovirus receptor engagement, internalization, endosomal maturation, endosomal escape and trafficking to the nuclear pore. A better understanding of this initial part of the adenovirus lifecycle may identify new mechanistic-based treatments for adenovirus-induced diseases and help in the engineering of more efficient vectors.
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Affiliation(s)
- Daniel Henaff
- Institut de Génétique Moléculaire de Montpellier, CNRS UMR 5535, 34293 Montpellier, France
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44
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Adenovirus structural protein IIIa is involved in the serotype specificity of viral DNA packaging. J Virol 2011; 85:7849-55. [PMID: 21632753 DOI: 10.1128/jvi.00467-11] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The packaging of the adenovirus (Ad) genome into a capsid displays serotype specificity. This specificity has been attributed to viral packaging proteins, the IVa2 protein and the L1-52/55K protein. We previously found that the Ad17 L1-52/55K protein was not able to complement the growth of an Ad5 L1-52/55K mutant virus, whereas two other Ad17 packaging proteins, IVa2 and L4-22K, could complement the growth of Ad5 viruses with mutations in the respective genes. In this report, we investigated why the Ad17 L1-52/55K protein was not able to complement the Ad5 L1-52/55K mutant virus. We demonstrate that the Ad17 L1-52/55K protein binds to the Ad5 IVa2 protein in vitro and the Ad5 packaging domain in vivo, activities previously associated with packaging function. The Ad17 L1-52/55K protein also associates with empty Ad5 capsids. Interestingly, we find that the Ad17 L1-52/55K protein is able to complement the growth of an Ad5 L1-52/55K mutant virus in conjunction with the Ad17 structural protein IIIa. The same result was found with the L1-52/55K and IIIa proteins of several other Ad serotypes, including Ad3 and Ad4. The Ad17 IIIa protein associates with empty Ad5 capsids. Consistent with the complementation results, we find that the IIIa protein interacts with the L1-52/55K protein in vitro and associates with the viral packaging domain in vivo. These results underscore the complex nature of virus assembly and genome encapsidation and provide a new model for how the viral genome may tether to the empty capsid during the encapsidation process.
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Unnatural amino acid incorporation onto adenoviral (Ad) coat proteins facilitates chemoselective modification and retargeting of Ad type 5 vectors. J Virol 2011; 85:7546-54. [PMID: 21613404 DOI: 10.1128/jvi.00118-11] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Surface modification of adenovirus vectors can improve tissue-selective targeting, attenuate immunogenicity, and enable imaging of particle biodistribution, thus significantly improving therapeutic potential. Currently, surface engineering is constrained by a combination of factors, including impact on viral fitness, limited access to functionality, or incomplete control over the site of modification. Here, we report a two-step labeling process involving an initial metabolic placement of a uniquely reactive unnatural amino acid, azidohomoalanine (Aha), followed by highly specific chemical modification. As genetic modification of adenovirus is unnecessary, vector production is exceedingly straightforward. Aha incorporation demonstrated no discernible impact on either virus production or infectivity of the resultant particles. "Click" chemical modification of surface-exposed azides was highly selective, allowing for the attachment of a wide range of functionality. Decoration of human adenovirus type 5 (hAd5) with folate, a known cancer-targeting moiety, provided an ∼20-fold increase in infection of murine breast cancer cells (4T1) in a folate receptor-dependent manner. This study demonstrates that incorporation of unnatural amino acids can provide a flexible, straightforward route for the selective chemical modification of adenoviral vectors.
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Woetzel N, Lindert S, Stewart PL, Meiler J. BCL::EM-Fit: rigid body fitting of atomic structures into density maps using geometric hashing and real space refinement. J Struct Biol 2011; 175:264-76. [PMID: 21565271 DOI: 10.1016/j.jsb.2011.04.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 04/28/2011] [Accepted: 04/28/2011] [Indexed: 11/30/2022]
Abstract
Cryo-electron microscopy (cryoEM) can visualize large macromolecular assemblies at resolutions often below 10Å and recently as good as 3.8-4.5 Å. These density maps provide important insights into the biological functioning of molecular machineries such as viruses or the ribosome, in particular if atomic-resolution crystal structures or models of individual components of the assembly can be placed into the density map. The present work introduces a novel algorithm termed BCL::EM-Fit that accurately fits atomic-detail structural models into medium resolution density maps. In an initial step, a "geometric hashing" algorithm provides a short list of likely placements. In a follow up Monte Carlo/Metropolis refinement step, the initial placements are optimized by their cross correlation coefficient. The resolution of density maps for a reliable fit was determined to be 10 Å or better using tests with simulated density maps. The algorithm was applied to fitting of capsid proteins into an experimental cryoEM density map of human adenovirus at a resolution of 6.8 and 9.0 Å, and fitting of the GroEL protein at 5.4 Å. In the process, the handedness of the cryoEM density map was unambiguously identified. The BCL::EM-Fit algorithm offers an alternative to the established Fourier/Real space fitting programs. BCL::EM-Fit is free for academic use and available from a web server or as downloadable binary file at http://www.meilerlab.org.
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Affiliation(s)
- Nils Woetzel
- Department of Chemistry, Vanderbilt University, TN 37212, USA
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Moyer CL, Wiethoff CM, Maier O, Smith JG, Nemerow GR. Functional genetic and biophysical analyses of membrane disruption by human adenovirus. J Virol 2011; 85:2631-41. [PMID: 21209115 PMCID: PMC3067937 DOI: 10.1128/jvi.02321-10] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/23/2010] [Indexed: 02/07/2023] Open
Abstract
The identification of the adenovirus (AdV) protein that mediates endosome penetration during infection has remained elusive. Several lines of evidence from previous studies suggest that the membrane lytic factor of AdV is the internal capsid protein VI. While these earlier results imply a role for protein VI in endosome disruption, direct evidence during cell entry has not been demonstrated. To acquire more definitive proof, we engineered random mutations in a critical N-terminal amphipathic α-helix of VI in an attempt to generate AdV mutants that lack efficient membrane penetration and infection. Random mutagenesis within the context of the AdV genome was achieved via the development of a novel technique that incorporates both error-prone PCR and recombineering. Using this system, we identified a single mutation, L40Q, that significantly reduced infectivity and selectively impaired endosome penetration. Furthermore, we obtained biophysical data showing that the lack of efficient endosomalysis is associated with reduced insertion of the L40Q mutation in protein VI (VI-L40Q) into membranes. Our studies indicate that protein VI is the critical membrane lytic factor of AdV during cellular entry and reveal the biochemical basis for its membrane interactions.
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Affiliation(s)
- Crystal L. Moyer
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois, Department of Microbiology, University of Washington School of Medicine, Seattle, Washington
| | - Christopher M. Wiethoff
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois, Department of Microbiology, University of Washington School of Medicine, Seattle, Washington
| | - Oana Maier
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois, Department of Microbiology, University of Washington School of Medicine, Seattle, Washington
| | - Jason G. Smith
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois, Department of Microbiology, University of Washington School of Medicine, Seattle, Washington
| | - Glen R. Nemerow
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, California, Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, Illinois, Department of Microbiology, University of Washington School of Medicine, Seattle, Washington
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Zhou ZH. Atomic resolution cryo electron microscopy of macromolecular complexes. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2011; 82:1-35. [PMID: 21501817 PMCID: PMC3698602 DOI: 10.1016/b978-0-12-386507-6.00001-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Single-particle cryo electron microscopy (cryoEM) is a technique for determining three-dimensional (3D) structures from projection images of molecular complexes preserved in their "native," noncrystalline state. Recently, atomic or near-atomic resolution structures of several viruses and protein assemblies have been determined by single-particle cryoEM, allowing ab initio atomic model building by following the amino acid side chains or nucleic acid bases identifiable in their cryoEM density maps. In particular, these cryoEM structures have revealed extended arms contributing to molecular interactions that are otherwise not resolved by the conventional structural method of X-ray crystallography at similar resolutions. High-resolution cryoEM requires careful consideration of a number of factors, including proper sample preparation to ensure structural homogeneity, optimal configuration of electron imaging conditions to record high-resolution cryoEM images, accurate determination of image parameters to correct image distortions, efficient refinement and computation to reconstruct a 3D density map, and finally appropriate choice of modeling tools to construct atomic models for functional interpretation. This progress illustrates the power of cryoEM and ushers it into the arsenal of structural biology, alongside conventional techniques of X-ray crystallography and NMR, as a major tool (and sometimes the preferred one) for the studies of molecular interactions in supramolecular assemblies or machines.
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Affiliation(s)
- Z Hong Zhou
- Department of Microbiology, Immunology & Molecular Genetics, University of California, Los Angeles (UCLA), Los Angeles, California, USA
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Liu H, Wu L, Zhou ZH. Model of the trimeric fiber and its interactions with the pentameric penton base of human adenovirus by cryo-electron microscopy. J Mol Biol 2010; 406:764-74. [PMID: 21146538 DOI: 10.1016/j.jmb.2010.11.043] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 11/12/2010] [Accepted: 11/22/2010] [Indexed: 01/30/2023]
Abstract
Adenovirus invades host cells by first binding to host receptors through a trimeric fiber, which contains three domains: a receptor-binding knob domain, a long flexible shaft domain, and a penton base-attachment tail domain. Although the structure of the knob domain associated with a portion of the shaft has been solved by X-ray crystallography, the in situ structure of the fiber in the virion is not known; thus, it remains a mystery how the trimeric fiber attaches to its underlying pentameric penton base. By high-resolution cryo-electron microscopy, we have determined the structure of the human adenovirus type 5 (Ad5) to 3.6-Å resolution and have reported the full atomic models for its capsid proteins, but not for the fiber whose density cannot be directly interpreted due to symmetry mismatch with the penton base. Here, we report the determination of the Ad5 fiber structure and its mode of attachment to the pentameric penton base by using an integrative approach of multi-resolution filtering, homology modeling, computational simulation of mismatched symmetries, and fitting of atomic models into cryo-electron microscopy density maps. Our structure reveals that the interactions between the trimeric fiber and the pentameric penton base are mediated by a hydrophobic ring on the top surface of the penton base and three flexible tails inserted into three of the five available grooves formed by neighboring subunits of penton base. These interaction sites provide the molecular basis for the symmetry mismatch and can be targeted for optimizing adenovirus for gene therapy applications.
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Affiliation(s)
- Hongrong Liu
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095-7364, USA
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50
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de Vrij J, van den Hengel SK, Uil TG, Koppers-Lalic D, Dautzenberg IJC, Stassen OMJA, Bárcena M, Yamamoto M, de Ridder CMA, Kraaij R, Kwappenberg KM, Schilham MW, Hoeben RC. Enhanced transduction of CAR-negative cells by protein IX-gene deleted adenovirus 5 vectors. Virology 2010; 410:192-200. [PMID: 21130482 PMCID: PMC7111976 DOI: 10.1016/j.virol.2010.10.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 10/13/2010] [Accepted: 10/29/2010] [Indexed: 01/14/2023]
Abstract
In human adenoviruses (HAdV), 240 copies of the 14.3-kDa minor capsid protein IX stabilize the capsid. Three N-terminal domains of protein IX form triskelions between hexon capsomers. The C-terminal domains of four protein IX monomers associate near the facet periphery. The precise biological role of protein IX remains enigmatic. Here we show that deletion of the protein IX gene from a HAdV-5 vector enhanced the reporter gene delivery 5 to 25-fold, specifically to Coxsackie and Adenovirus Receptor (CAR)-negative cell lines. Deletion of the protein IX gene also resulted in enhanced activation of peripheral blood mononuclear cells. The mechanism for the enhanced transduction is obscure. No differences in fiber loading, integrin-dependency of transduction, or factor-X binding could be established between protein IX-containing and protein IX-deficient particles. Our data suggest that protein IX can affect the cell tropism of HAdV-5, and may function to dampen the innate immune responses against HAdV particles.
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Affiliation(s)
- Jeroen de Vrij
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
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