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Martín-González N, Gómez-González A, Hernando-Pérez M, Bauer M, Greber UF, San Martín C, de Pablo PJ. Adenovirus core protein V reinforces the capsid and enhances genome release from disrupted particles. SCIENCE ADVANCES 2023; 9:eade9910. [PMID: 37027464 PMCID: PMC10081844 DOI: 10.1126/sciadv.ade9910] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 03/02/2023] [Indexed: 06/19/2023]
Abstract
Out of the three core proteins in human adenovirus, protein V is believed to connect the inner capsid surface to the outer genome layer. Here, we explored mechanical properties and in vitro disassembly of particles lacking protein V (Ad5-ΔV). Ad5-ΔV particles were softer and less brittle than the wild-type ones (Ad5-wt), but they were more prone to release pentons under mechanical fatigue. In Ad5-ΔV, core components did not readily diffuse out of partially disrupted capsids, and the core appeared more condensed than in Ad5-wt. These observations suggest that instead of condensing the genome, protein V antagonizes the condensing action of the other core proteins. Protein V provides mechanical reinforcement and facilitates genome release by keeping DNA connected to capsid fragments that detach during disruption. This scenario is in line with the location of protein V in the virion and its role in Ad5 cell entry.
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Affiliation(s)
- Natalia Martín-González
- Departament of Condensed Matter Physics, Universidad Autónoma de Madrid and Institute of Condensed Matter Physics (IFIMAC), 28049 Madrid, Spain
| | - Alfonso Gómez-González
- Department of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Mercedes Hernando-Pérez
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), 28049 Madrid, Spain
| | - Michael Bauer
- Department of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Urs F. Greber
- Department of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland
| | - Carmen San Martín
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), 28049 Madrid, Spain
| | - Pedro J. de Pablo
- Departament of Condensed Matter Physics, Universidad Autónoma de Madrid and Institute of Condensed Matter Physics (IFIMAC), 28049 Madrid, Spain
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2
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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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3
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Suomalainen M, Greber UF. Virus Infection Variability by Single-Cell Profiling. Viruses 2021; 13:1568. [PMID: 34452433 PMCID: PMC8402812 DOI: 10.3390/v13081568] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 07/30/2021] [Accepted: 08/05/2021] [Indexed: 12/15/2022] Open
Abstract
Cell-to-cell variability of infection has long been known, yet it has remained one of the least understood phenomena in infection research. It impacts on disease onset and development, yet only recently underlying mechanisms have been studied in clonal cell cultures by single-virion immunofluorescence microscopy and flow cytometry. In this review, we showcase how single-cell RNA sequencing (scRNA-seq), single-molecule RNA-fluorescence in situ hybridization (FISH), and copper(I)-catalyzed azide-alkyne cycloaddition (click) with alkynyl-tagged viral genomes dissect infection variability in human and mouse cells. We show how the combined use of scRNA-FISH and click-chemistry reveals highly variable onsets of adenoviral gene expression, and how single live cell plaques reveal lytic and nonlytic adenovirus transmissions. The review highlights how scRNA-seq profiling and scRNA-FISH of coxsackie, influenza, dengue, zika, and herpes simplex virus infections uncover transcriptional variability, and how the host interferon response tunes influenza and sendai virus infections. We introduce the concept of "cell state" in infection variability, and conclude with advances by single-cell simultaneous measurements of chromatin accessibility and mRNA counts at high-throughput. Such technology will further dissect the sequence of events in virus infection and pathology, and better characterize the genetic and genomic stability of viruses, cell autonomous innate immune responses, and mechanisms of tissue injury.
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Affiliation(s)
- Maarit Suomalainen
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Urs F. Greber
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
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4
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Daussy CF, Pied N, Wodrich H. Understanding Post Entry Sorting of Adenovirus Capsids; A Chance to Change Vaccine Vector Properties. Viruses 2021; 13:v13071221. [PMID: 34202573 PMCID: PMC8310329 DOI: 10.3390/v13071221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 06/15/2021] [Accepted: 06/17/2021] [Indexed: 12/25/2022] Open
Abstract
Adenovirus vector-based genetic vaccines have emerged as a powerful strategy against the SARS-CoV-2 health crisis. This success is not unexpected because adenoviruses combine many desirable features of a genetic vaccine. They are highly immunogenic and have a low and well characterized pathogenic profile paired with technological approachability. Ongoing efforts to improve adenovirus-vaccine vectors include the use of rare serotypes and non-human adenoviruses. In this review, we focus on the viral capsid and how the choice of genotypes influences the uptake and subsequent subcellular sorting. We describe how understanding capsid properties, such as stability during the entry process, can change the fate of the entering particles and how this translates into differences in immunity outcomes. We discuss in detail how mutating the membrane lytic capsid protein VI affects species C viruses' post-entry sorting and briefly discuss if such approaches could have a wider implication in vaccine and/or vector development.
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5
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Andriasyan V, Yakimovich A, Petkidis A, Georgi F, Witte R, Puntener D, Greber UF. Microscopy deep learning predicts virus infections and reveals mechanics of lytic-infected cells. iScience 2021; 24:102543. [PMID: 34151222 PMCID: PMC8192562 DOI: 10.1016/j.isci.2021.102543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/07/2021] [Accepted: 05/12/2021] [Indexed: 02/07/2023] Open
Abstract
Imaging across scales reveals disease mechanisms in organisms, tissues, and cells. Yet, particular infection phenotypes, such as virus-induced cell lysis, have remained difficult to study. Here, we developed imaging modalities and deep learning procedures to identify herpesvirus and adenovirus (AdV) infected cells without virus-specific stainings. Fluorescence microscopy of vital DNA-dyes and live-cell imaging revealed learnable virus-specific nuclear patterns transferable to related viruses of the same family. Deep learning predicted two major AdV infection outcomes, non-lytic (nonspreading) and lytic (spreading) infections, up to about 20 hr prior to cell lysis. Using these predictive algorithms, lytic and non-lytic nuclei had the same levels of green fluorescent protein (GFP)-tagged virion proteins but lytic nuclei enriched the virion proteins faster, and collapsed more extensively upon laser-rupture than non-lytic nuclei, revealing impaired mechanical properties of lytic nuclei. Our algorithms may be used to infer infection phenotypes of emerging viruses, enhance single cell biology, and facilitate differential diagnosis of non-lytic and lytic infections. Artificial intelligence identifies HSV- and AdV-infected cells without specific probes. Imaging lytic-infected cells reveals nuclear envelope rupture and AdV dissemination. Live cell imaging and neural networks presciently pinpoint lytic-infected cells. Lytic-infected cell nuclei have mechanical properties distinct from non-lytic nuclei.
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Affiliation(s)
- Vardan Andriasyan
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland
| | - Artur Yakimovich
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland.,University College London, London WC1E 6BT, UK.,Artificial Intelligence for Life Sciences CIC, London N8 7FJ, UK
| | - Anthony Petkidis
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland
| | - Fanny Georgi
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland
| | - Robert Witte
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland
| | - Daniel Puntener
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland.,Roche Diagnostics International Ltd, Rotkreuz 6343, Switzerland
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zürich, Zürich 8057, Switzerland
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6
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Georgi F, Andriasyan V, Witte R, Murer L, Hemmi S, Yu L, Grove M, Meili N, Kuttler F, Yakimovich A, Turcatti G, Greber UF. The FDA-Approved Drug Nelfinavir Inhibits Lytic Cell-Free but Not Cell-Associated Nonlytic Transmission of Human Adenovirus. Antimicrob Agents Chemother 2020; 64:e01002-20. [PMID: 32601166 PMCID: PMC7449217 DOI: 10.1128/aac.01002-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 06/19/2020] [Indexed: 02/07/2023] Open
Abstract
Adenoviruses (AdVs) are prevalent and give rise to chronic and recurrent disease. Human AdV (HAdV) species B and C, such as HAdV-C2, -C5, and -B14, cause respiratory disease and constitute a health threat for immunocompromised individuals. HAdV-Cs are well known for lysing cells owing to the E3 CR1-β-encoded adenovirus death protein (ADP). We previously reported a high-throughput image-based screening framework and identified an inhibitor of HAdV-C2 multiround infection, nelfinavir mesylate. Nelfinavir is the active ingredient of Viracept, an FDA-approved inhibitor of human immunodeficiency virus (HIV) aspartyl protease that is used to treat AIDS. It is not effective against single-round HAdV infections. Here, we show that nelfinavir inhibits lytic cell-free transmission of HAdV, indicated by the suppression of comet-shaped infection foci in cell culture. Comet-shaped foci occur upon convection-based transmission of cell-free viral particles from an infected cell to neighboring uninfected cells. HAdV lacking ADP was insensitive to nelfinavir but gave rise to comet-shaped foci, indicating that ADP enhances but is not required for cell lysis. This was supported by the notion that HAdV-B14 and -B14p1 lacking ADP were highly sensitive to nelfinavir, although HAdV-A31, -B3, -B7, -B11, -B16, -B21, -D8, -D30, and -D37 were less sensitive. Conspicuously, nelfinavir uncovered slow-growing round HAdV-C2 foci, independent of neutralizing antibodies in the medium, indicative of nonlytic cell-to-cell transmission. Our study demonstrates the repurposing potential of nelfinavir with postexposure efficacy against different HAdVs and describes an alternative nonlytic cell-to-cell transmission mode of HAdV.
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Affiliation(s)
- Fanny Georgi
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Vardan Andriasyan
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Robert Witte
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Luca Murer
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Silvio Hemmi
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Lisa Yu
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Melanie Grove
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Nicole Meili
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Fabien Kuttler
- Biomolecular Screening Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Artur Yakimovich
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
- Artificial Intelligence for Life Sciences CIC, London, United Kingdom
| | - Gerardo Turcatti
- Biomolecular Screening Facility, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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7
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Georgi F, Greber UF. The Adenovirus Death Protein - a small membrane protein controls cell lysis and disease. FEBS Lett 2020; 594:1861-1878. [PMID: 32472693 DOI: 10.1002/1873-3468.13848] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/16/2022]
Abstract
Human adenoviruses (HAdVs) cause widespread acute and persistent infections. Infections are usually mild and controlled by humoral and cell-based immunity. Reactivation of persistently infected immune cells can lead to a life-threatening disease in immunocompromised individuals, especially children and transplant recipients. To date, no effective therapy or vaccine against HAdV disease is available to the public. HAdV-C2 and C5 are the best-studied of more than 100 HAdV types. They persist in infected cells and release their progeny by host cell lysis to neighbouring cells and fluids, a process facilitated by the adenovirus death protein (ADP). ADP consists of about 100 amino acids and harbours a single membrane-spanning domain. It undergoes post-translational processing in endoplasmic reticulum and Golgi compartments, before localizing to the inner nuclear membrane. Here, we discuss the current knowledge on how ADP induces membrane rupture. Membrane rupture is essential for both progression of disease and efficacy of therapeutic viruses in clinical applications, in particular oncolytic therapy.
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Affiliation(s)
- Fanny Georgi
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | - Urs F Greber
- Department of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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8
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Barry MA, Rubin JD, Lu SC. Retargeting adenoviruses for therapeutic applications and vaccines. FEBS Lett 2020; 594:1918-1946. [PMID: 31944286 PMCID: PMC7311308 DOI: 10.1002/1873-3468.13731] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 12/29/2022]
Abstract
Adenoviruses (Ads) are robust vectors for therapeutic applications and vaccines, but their use can be limited by differences in their in vitro and in vivo pharmacologies. This review emphasizes that there is not just one Ad, but a whole virome of diverse viruses that can be used as therapeutics. It discusses that true vector targeting involves not only retargeting viruses, but importantly also detargeting the viruses from off-target cells.
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Affiliation(s)
- Michael A Barry
- Department of Medicine, Division of Infectious Diseases, Department of Immunology, Department of Molecular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Jeffrey D Rubin
- Virology and Gene Therapy Graduate Program, Mayo Graduate School, Mayo Clinic, Rochester, MN, USA
| | - Shao-Chia Lu
- Virology and Gene Therapy Graduate Program, Mayo Graduate School, Mayo Clinic, Rochester, MN, USA
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9
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Goradel NH, Negahdari B, Ghorghanlu S, Jahangiri S, Arashkia A. Strategies for enhancing intratumoral spread of oncolytic adenoviruses. Pharmacol Ther 2020; 213:107586. [PMID: 32479843 DOI: 10.1016/j.pharmthera.2020.107586] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 05/11/2020] [Indexed: 02/06/2023]
Abstract
Oncolytic viruses, effectively replicate viruses within malignant cells to lyse them without affecting normal ones, have recently shown great promise in developing therapeutic options for cancer. Adenoviruses (Ads) are one of the candidates in oncolytic virotheraoy due to its easily manipulated genomic DNA and expression of wide rane of its receptors on the various cancers. Although systematic delivery of oncolytic adenoviruses can target both primary and metastatic tumors, there are some drawbacks in the effective systematic delivery of oncolytic adenoviruses, including pre-existing antibodies and liver tropism. To overcome these limitations, intratumural (IT) administration of oncolytic viruses have been proposed. However, IT injection of Ads leaves much of the tumor mass unaffected and Ads are not able to disperse more in the tumor microenvironment (TME). To this end, various strategies have been developed to enhance the IT spread of oncolytic adenoviruses, such as using extracellular matrix degradation enzymes, junction opening peptides, and fusogenic proteins. In the present paper, we reviewed different oncolytic adenoviruses, their application in the clinical trials, and strategies for enhancing their IT spread.
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Affiliation(s)
- Nasser Hashemi Goradel
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Babak Negahdari
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Sajjad Ghorghanlu
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Samira Jahangiri
- Department of Bacteriology and Virology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Arash Arashkia
- Department of Molecular Virology, Pasteur Institute of Iran, Tehran, Iran.
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10
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Dynamic competition for hexon binding between core protein VII and lytic protein VI promotes adenovirus maturation and entry. Proc Natl Acad Sci U S A 2020; 117:13699-13707. [PMID: 32467158 DOI: 10.1073/pnas.1920896117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Adenovirus minor coat protein VI contains a membrane-disrupting peptide that is inactive when VI is bound to hexon trimers. Protein VI must be released during entry to ensure endosome escape. Hexon:VI stoichiometry has been uncertain, and only fragments of VI have been identified in the virion structure. Recent findings suggest an unexpected relationship between VI and the major core protein, VII. According to the high-resolution structure of the mature virion, VI and VII may compete for the same binding site in hexon; and noninfectious human adenovirus type 5 particles assembled in the absence of VII (Ad5-VII-) are deficient in proteolytic maturation of protein VI and endosome escape. Here we show that Ad5-VII- particles are trapped in the endosome because they fail to increase VI exposure during entry. This failure was not due to increased particle stability, because capsid disruption happened at lower thermal or mechanical stress in Ad5-VII- compared to wild-type (Ad5-wt) particles. Cryoelectron microscopy difference maps indicated that VII can occupy the same binding pocket as VI in all hexon monomers, strongly arguing for binding competition. In the Ad5-VII- map, density corresponding to the immature amino-terminal region of VI indicates that in the absence of VII the lytic peptide is trapped inside the hexon cavity, and clarifies the hexon:VI stoichiometry conundrum. We propose a model where dynamic competition between proteins VI and VII for hexon binding facilitates the complete maturation of VI, and is responsible for releasing the lytic protein from the hexon cavity during entry and stepwise uncoating.
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11
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Greisch JF, Tamara S, Scheltema RA, Maxwell HWR, Fagerlund RD, Fineran PC, Tetter S, Hilvert D, Heck AJR. Expanding the mass range for UVPD-based native top-down mass spectrometry. Chem Sci 2019; 10:7163-7171. [PMID: 31588283 PMCID: PMC6764275 DOI: 10.1039/c9sc01857c] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/30/2019] [Indexed: 12/13/2022] Open
Abstract
Native top-down proteomics using UVPD extended to mega Dalton protein assemblies.
Native top-down mass spectrometry is emerging as a methodology that can be used to structurally investigate protein assemblies. To extend the possibilities of native top-down mass spectrometry to larger and more heterogeneous biomolecular assemblies, advances in both the mass analyzer and applied fragmentation techniques are still essential. Here, we explore ultraviolet photodissociation (UVPD) of protein assemblies on an Orbitrap with extended mass range, expanding its usage to large and heterogeneous macromolecular complexes, reaching masses above 1 million Da. We demonstrate that UVPD can lead not only to the ejection of intact subunits directly from such large intact complexes, but also to backbone fragmentation of these subunits, providing enough sequence information for subunit identification. The Orbitrap mass analyzer enables simultaneous monitoring of the precursor, the subunits, and the subunit fragments formed upon UVPD activation. While only partial sequence coverage of the subunits is observed, the UVPD data yields information about the localization of chromophores covalently attached to the subunits of the light harvesting complex B-phycoerythrin, extensive backbone fragmentation in a subunit of a CRISPR-Cas Csy (type I–F Cascade) complex, and sequence modifications in a virus-like proteinaceous nano-container. Through these multiple applications we demonstrate for the first time that UVPD based native top-down mass spectrometry is feasible for large and heterogeneous particles, including ribonucleoprotein complexes and MDa virus-like particles.
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Affiliation(s)
- Jean-François Greisch
- Biomolecular Mass Spectrometry and Proteomics , Bijvoet Center for Biomolecular Research , Utrecht Institute of Pharmaceutical Sciences , Utrecht University , Padualaan 8 , 3584 Utrecht , The Netherlands . .,Netherlands Proteomics Center , Padualaan 8 , 3584 Utrecht , The Netherlands
| | - Sem Tamara
- Biomolecular Mass Spectrometry and Proteomics , Bijvoet Center for Biomolecular Research , Utrecht Institute of Pharmaceutical Sciences , Utrecht University , Padualaan 8 , 3584 Utrecht , The Netherlands . .,Netherlands Proteomics Center , Padualaan 8 , 3584 Utrecht , The Netherlands
| | - Richard A Scheltema
- Biomolecular Mass Spectrometry and Proteomics , Bijvoet Center for Biomolecular Research , Utrecht Institute of Pharmaceutical Sciences , Utrecht University , Padualaan 8 , 3584 Utrecht , The Netherlands . .,Netherlands Proteomics Center , Padualaan 8 , 3584 Utrecht , The Netherlands
| | - Howard W R Maxwell
- Department of Microbiology and Immunology , University of Otago , PO Box 56 , 9054 Dunedin , New Zealand
| | - Robert D Fagerlund
- Department of Microbiology and Immunology , University of Otago , PO Box 56 , 9054 Dunedin , New Zealand
| | - Peter C Fineran
- Department of Microbiology and Immunology , University of Otago , PO Box 56 , 9054 Dunedin , New Zealand
| | - Stephan Tetter
- Laboratory of Organic Chemistry , Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir-Prelog-Weg 1-5/10 , 8093 Zürich , Switzerland
| | - Donald Hilvert
- Laboratory of Organic Chemistry , Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir-Prelog-Weg 1-5/10 , 8093 Zürich , Switzerland
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics , Bijvoet Center for Biomolecular Research , Utrecht Institute of Pharmaceutical Sciences , Utrecht University , Padualaan 8 , 3584 Utrecht , The Netherlands . .,Netherlands Proteomics Center , Padualaan 8 , 3584 Utrecht , The Netherlands
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12
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Fast, selective and quantitative protein profiling of adenovirus-vector based vaccines by ultra-performance liquid chromatography. J Chromatogr A 2018; 1581-1582:25-32. [PMID: 30389208 PMCID: PMC7094600 DOI: 10.1016/j.chroma.2018.10.045] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 10/19/2018] [Accepted: 10/22/2018] [Indexed: 11/22/2022]
Abstract
A validated method for quantitative protein profiling in adenovirus-based vaccines. 14 Adenovirus proteins baseline separated within 17 min by RP-UPLC. Adenovirus-based samples directly injected, needing no sample pretreatment. The method can detect and quantify protein degradants.
A method for the quantitative determination of the protein composition of adenovirus-vector based vaccines was developed. The final method used RP-UPLC with UV absorbance detection, a C4 column (300 Å, 1.7 μm, 2.1 × 150 mm), and a water- acetonitrile (ACN) gradient containing trifluoroacetic acid (TFA) as ion-pairing agent. The chromatographic resolution between the various adenovirus proteins was optimized by studying the effect of the TFA concentration and the column temperature, applying a full factorial design of experiments. A reproducible baseline separation of all relevant adenovirus proteins could be achieved within 17 min run time. Samples containing adenovirus particles could be directly injected into the UPLC system without sample pretreatment. The viruses reproducibly dissociate into proteins in the UPLC system upon contact with the mobile phase containing ACN. The new RP-UPLC method was successfully validated for protein profiling and relative quantification of proteins in vaccine products based on adenovirus vector types 26 and 35. The intermediate precision of the relative peak areas of all proteins was between 1% and 14% RSD, except for the peak assigned to protein V (26% RSD). The method proved to be stability indicating with respect to thermal and oxidation stress of the adenovirus-vector based vaccine and was successfully implemented for the characterization of adenovirus-based products.
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13
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Revised Crystal Structure of Human Adenovirus Reveals the Limits on Protein IX Quasi-Equivalence and on Analyzing Large Macromolecular Complexes. J Mol Biol 2018; 430:4132-4141. [PMID: 30121295 DOI: 10.1016/j.jmb.2018.08.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/19/2018] [Accepted: 08/04/2018] [Indexed: 11/23/2022]
Abstract
We report the revised crystal structure of a pseudo-typed human adenovirus at 3.8-Å resolution that is consistent with the atomic models of minor proteins determined by cryo-electron microscopy. The diffraction data from multiple crystals were rescaled and merged to increase the data completeness. The densities for the minor proteins were initially identified in the phase-refined omit maps that were further improved by the phases from docked poly-alanine models to build atomic structures. While the trimeric fiber molecules are disordered due to flexibility and imposition of 5-fold symmetry, the remaining major capsid proteins hexon and penton base are clearly ordered, with the exception of hypervariable region 1 of hexons, the RGD containing loop, and the N-termini of the penton base. The exterior minor protein IX together with the interior minor proteins IIIa and VIII stabilizes the adenovirus virion. A segment of N-terminal pro-peptide of VI is found in the interior cavities of peripentonal hexons, and the rest of VI is disordered. While the triskelion substructures formed by the N-termini of IX conform to excellent quasi 3-fold symmetry, the tetrameric coiled-coils formed by the C-termini and organized in parallel and anti-parallel arrangement do not exhibit any quasi-symmetry. This observation also conveys the pitfalls of using the quasi-equivalence as validation criteria for the structural analysis of extended (non-modular) capsid proteins such as IX. Together, these results remedy certain discrepancies in the previous X-ray model in agreement with the cryo-electron microscopy models.
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14
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Talele TT. Natural-Products-Inspired Use of the gem-Dimethyl Group in Medicinal Chemistry. J Med Chem 2017; 61:2166-2210. [DOI: 10.1021/acs.jmedchem.7b00315] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Tanaji T. Talele
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, Queens, New York 11439, United States
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15
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Studies on the Interaction of Tumor-Derived HD5 Alpha Defensins with Adenoviruses and Implications for Oncolytic Adenovirus Therapy. J Virol 2017; 91:JVI.02030-16. [PMID: 28077642 DOI: 10.1128/jvi.02030-16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 12/20/2016] [Indexed: 12/19/2022] Open
Abstract
Defensins are small antimicrobial peptides capable of neutralizing human adenovirus (HAdV) in vitro by binding capsid proteins and blocking endosomal escape of virus. In humans, the alpha defensin HD5 is produced by specialized epithelial cells of the gastrointestinal and genito-urinary tracts. Here, we demonstrate, using patient biopsy specimens, that HD5 is also expressed as an active, secreted peptide by epithelial ovarian and lung cancer cells in situ This finding prompted us to study the role of HD5 in infection and spread of replication-competent, oncolytic HAdV type 3 (HAdV3). HAdV3 produces large amounts of penton-dodecahedra (PtDd), virus-like particles, during replication. We have previously shown that PtDd are involved in opening epithelial junctions, thus facilitating lateral spread of de novo-produced virions. Here, we describe a second function of PtDd, namely, the blocking of HD5. A central tool to prove that viral PtDd neutralize HD5 and support spread of progeny virus was an HAdV3 mutant virus in which formation of PtDd was disabled (mut-Ad3GFP, where GFP is green fluorescent protein). We demonstrated that viral spread of mut-Ad3GFP was blocked by synthetic HD5 whereas that of the wild-type (wt) form (wt-Ad3GFP) was only minimally impacted. In human colon cancer Caco-2 cells, induction of cellular HD5 expression by fibroblast growth factor 9 (FGF9) significantly inhibited viral spread and progeny virus production of mut-Ad3GFP but not of wt-Ad3GFP. Finally, the ectopic expression of HD5 in tumor cells diminished the in vivo oncolytic activity of mut-Ad3GFP but not of wt-Ad3GFP. These data suggest a new mechanism of HAdV3 to overcome innate antiviral host responses. Our study has implications for oncolytic adenovirus therapy.IMPORTANCE Previously, it has been reported that human defensin HD5 inactivates specific human adenoviruses by binding to capsid proteins and blocking endosomal escape of virus. The central new findings described in our manuscript are the following: (i) the discovery of a new mechanism used by human adenovirus serotype 3 to overcome innate antiviral host responses that is based on the capacity of HAdV3 to produce subviral penton-dodecahedral particles that act as decoys for HD5, thus preventing the inactivation of virus progeny produced upon replication; (ii) the demonstration that ectopic HD5 expression in cancer cells decreases the oncolytic efficacy of a serotype 5-based adenovirus vector; and (iii) the demonstration that epithelial ovarian and lung cancers express HD5. The study improves our understanding of how adenoviruses establish infection in epithelial tissues and has implications for cancer therapy with oncolytic adenoviruses.
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16
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Yumul R, Richter M, Lu ZZ, Saydaminova K, Wang H, Wang CHK, Carter D, Lieber A. Epithelial Junction Opener Improves Oncolytic Adenovirus Therapy in Mouse Tumor Models. Hum Gene Ther 2016; 27:325-37. [PMID: 26993072 DOI: 10.1089/hum.2016.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A central resistance mechanism in solid tumors is the maintenance of epithelial junctions between malignant cells that prevent drug penetration into the tumor. Human adenoviruses (Ads) have evolved mechanisms to breach epithelial barriers. For example, during Ad serotype 3 (Ad3) infection of epithelial tumor cells, massive amounts of subviral penton-dodecahedral particles (PtDd) are produced and released from infected cells to trigger the transient opening of epithelial junctions, thus facilitating lateral virus spread. We show here that an Ad3 mutant that is disabled for PtDd production is significantly less effective in killing of epithelial human xenograft tumors than the wild-type Ad3 virus. Intratumoral spread and therapeutic effect of the Ad3 mutant was enhanced by co-administration of a small recombinant protein (JO; produced in Escherichia coli) that incorporated the minimal junction opening domains of PtDd. We then demonstrated that co-administration of JO with replication-competent Ads that do not produce PtDd (Ad5, Ad35) resulted in greater attenuation of tumor growth than virus injection alone. Furthermore, we genetically modified a conditionally replicating Ad5-based oncolytic Ad (Ad5Δ24) to express a secreted form of JO upon replication in tumor cells. The JO-expressing virus had a significantly greater antitumor effect than the unmodified AdΔ24 version. Our findings indicate that epithelial junctions limit the efficacy of oncolytic Ads and that this problem can be address by co-injection or expression of JO. JO has also the potential for improving cancer therapy with other types of oncolytic viruses.
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Affiliation(s)
- Roma Yumul
- 1 Division of Medical Genetics, University of Washington , Seattle, Washington
| | - Maximilian Richter
- 1 Division of Medical Genetics, University of Washington , Seattle, Washington
| | - Zhuo-Zhuang Lu
- 1 Division of Medical Genetics, University of Washington , Seattle, Washington.,2 National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention , Beijing, PR China
| | - Kamola Saydaminova
- 1 Division of Medical Genetics, University of Washington , Seattle, Washington
| | - Hongjie Wang
- 1 Division of Medical Genetics, University of Washington , Seattle, Washington
| | | | - Darrick Carter
- 4 Compliment Corp. , Seattle, Washington.,5 PAI Life Sciences Inc. , Seattle, Washington
| | - André Lieber
- 1 Division of Medical Genetics, University of Washington , Seattle, Washington.,4 Compliment Corp. , Seattle, Washington.,6 Department of Pathology, University of Washington , Seattle, Washington
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17
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Loison P, Majou D, Gelhaye E, Boudaud N, Gantzer C. Impact of reducing and oxidizing agents on the infectivity of Qβ phage and the overall structure of its capsid. FEMS Microbiol Ecol 2016; 92:fiw153. [PMID: 27402711 DOI: 10.1093/femsec/fiw153] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2016] [Indexed: 11/12/2022] Open
Abstract
Qβ phages infect Escherichia coli in the human gut by recognizing F-pili as receptors. Infection therefore occurs under reducing conditions induced by physiological agents (e.g. glutathione) or the intestinal bacterial flora. After excretion in the environment, phage particles are exposed to oxidizing conditions and sometimes disinfection. If inactivation does not occur, the phage may infect new hosts in the human gut through the oral route. During such a life cycle, we demonstrated that, outside the human gut, cysteines of the major protein capsid of Qβ phage form disulfide bonds. Disinfection with NaClO does not allow overoxidation to occur. Such oxidation induces inactivation rather by irreversible damage to the minor proteins. In the presence of glutathione, most disulfide bonds are reduced, which slightly increases the capacity of the phage to infect E. coli in vitro Such reduction is reversible and barely alters infectivity of the phage. Reduction of all disulfide bonds by dithiothreitol leads to complete capsid destabilization. These data provide new insights into how the phages are impacted by oxidizing-reducing conditions outside their host cell and raises the possibility of the intervention of the redox during life cycle of the phage.
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Affiliation(s)
- Pauline Loison
- LCPME (Laboratory of Physical Chemistry and Microbiology for the Environment), Joint Research Unit - UMR 7564, CNRS/Université de Lorraine, Nancy 54000, France CNRS, LCPME, UMR 7564, Institut Jean Barriol (IJB), Nancy 54000, France Food Safety Department, ACTALIA, Saint Lô 50000, France
| | - Didier Majou
- ACTIA, 16 rue Claude Bernard, 75231 Paris Cedex 05, France
| | - Eric Gelhaye
- Université de Lorraine, Tree-Microbe Interactions Department, UMR1136, F-54500 Vandœuvre-lès-Nancy, France INRA, Tree-Microbe Interactions Department, UMR1136, F-54280 Champenoux, France
| | | | - Christophe Gantzer
- LCPME (Laboratory of Physical Chemistry and Microbiology for the Environment), Joint Research Unit - UMR 7564, CNRS/Université de Lorraine, Nancy 54000, France CNRS, LCPME, UMR 7564, Institut Jean Barriol (IJB), Nancy 54000, France
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18
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Yamauchi Y, Greber UF. Principles of Virus Uncoating: Cues and the Snooker Ball. Traffic 2016; 17:569-92. [PMID: 26875443 PMCID: PMC7169695 DOI: 10.1111/tra.12387] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 02/10/2016] [Accepted: 02/10/2016] [Indexed: 12/17/2022]
Abstract
Viruses are spherical or complex shaped carriers of proteins, nucleic acids and sometimes lipids and sugars. They are metastable and poised for structural changes. These features allow viruses to communicate with host cells during entry, and to release the viral genome, a process known as uncoating. Studies have shown that hundreds of host factors directly or indirectly support this process. The cell provides molecules that promote stepwise virus uncoating, and direct the virus to the site of replication. It acts akin to a snooker player who delivers accurate and timely shots (cues) to the ball (virus) to score. The viruses, on the other hand, trick (snooker) the host, hijack its homeostasis systems, and dampen innate immune responses directed against danger signals. In this review, we discuss how cellular cues, facilitators, and built‐in viral mechanisms promote uncoating. Cues come from receptors, enzymes and chemicals that act directly on the virus particle to alter its structure, trafficking and infectivity. Facilitators are defined as host factors that are involved in processes which indirectly enhance entry or uncoating. Unraveling the mechanisms of virus uncoating will continue to enhance understanding of cell functions, and help counteracting infections with chemicals and vaccines.
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Affiliation(s)
- Yohei Yamauchi
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Urs F Greber
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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Infectio: a Generic Framework for Computational Simulation of Virus Transmission between Cells. mSphere 2016; 1:mSphere00078-15. [PMID: 27303704 PMCID: PMC4863613 DOI: 10.1128/msphere.00078-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/04/2016] [Indexed: 12/30/2022] Open
Abstract
Infectio presents a generalized platform to analyze virus infection spread between cells. It allows the simulation of plaque phenotypes from image-based assays. Viral plaques are the result of virus spreading from primary infected cells to neighboring cells. This is a complex process and involves neighborhood effects at cell-cell contact sites or fluid dynamics in the extracellular medium. Infectio differentiates between two major modes of virus transmission between cells, allowing in silico testing of hypotheses about spreading mechanisms of any virus which can be grown in cell cultures, based on experimentally measured parameters, such as infection intensity or cell killing. The results of these tests can be compared with experimental data and allow interpretations with regard to biophysical mechanisms. Infectio also facilitates characterizations of the mode of action of therapeutic agents, such as oncolytic viruses or other infectious or cytotoxic agents. Viruses spread between cells, tissues, and organisms by cell-free and cell-cell mechanisms, depending on the cell type, the nature of the virus, or the phase of the infection cycle. The mode of viral transmission has a large impact on disease development, the outcome of antiviral therapies or the efficacy of gene therapy protocols. The transmission mode of viruses can be addressed in tissue culture systems using live-cell imaging. Yet even in relatively simple cell cultures, the mechanisms of viral transmission are difficult to distinguish. Here we present a cross-platform software framework called “Infectio,” which is capable of simulating transmission phenotypes in tissue culture of virtually any virus. Infectio can estimate interdependent biological parameters, for example for vaccinia virus infection, and differentiate between cell-cell and cell-free virus spreading. Infectio assists in elucidating virus transmission mechanisms, a feature useful for designing strategies of perturbing or enhancing viral transmission. The complexity of the Infectio software is low compared to that of other software commonly used to quantitate features of cell biological images, which yields stable and relatively error-free output from Infectio. The software is open source (GPLv3 license), and operates on the major platforms (Windows, Mac, and Linux). The complete source code can be downloaded from http://infectio.github.io/index.html. IMPORTANCE Infectio presents a generalized platform to analyze virus infection spread between cells. It allows the simulation of plaque phenotypes from image-based assays. Viral plaques are the result of virus spreading from primary infected cells to neighboring cells. This is a complex process and involves neighborhood effects at cell-cell contact sites or fluid dynamics in the extracellular medium. Infectio differentiates between two major modes of virus transmission between cells, allowing in silico testing of hypotheses about spreading mechanisms of any virus which can be grown in cell cultures, based on experimentally measured parameters, such as infection intensity or cell killing. The results of these tests can be compared with experimental data and allow interpretations with regard to biophysical mechanisms. Infectio also facilitates characterizations of the mode of action of therapeutic agents, such as oncolytic viruses or other infectious or cytotoxic agents.
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20
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Mettenleiter TC. Breaching the Barrier-The Nuclear Envelope in Virus Infection. J Mol Biol 2015; 428:1949-61. [PMID: 26522933 DOI: 10.1016/j.jmb.2015.10.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 09/22/2015] [Accepted: 10/04/2015] [Indexed: 11/16/2022]
Abstract
Many DNA and a few RNA viruses use the host cell nucleus for virion formation and/or genome replication. To this end, the nuclear envelope (NE) barrier has to be overcome for entry into and egress from the intranuclear replication compartment. Different virus families have devised ingenious ways of entering and leaving the nucleus usurping cellular transport pathways through the nuclear pore complex but also translocating directly through both membranes of the NE. This intriguing diversity in nuclear entry and egress of viruses also highlights different ways nucleocytoplasmic transport can occur. Thus, the study of interactions between viruses and the NE also helps to unravel hitherto unknown cellular pathways such as vesicular nucleocytoplasmic transfer.
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Affiliation(s)
- Thomas C Mettenleiter
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
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21
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Intracellular Signaling and Desmoglein 2 Shedding Triggered by Human Adenoviruses Ad3, Ad14, and Ad14P1. J Virol 2015; 89:10841-59. [PMID: 26292319 DOI: 10.1128/jvi.01425-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 08/10/2015] [Indexed: 01/10/2023] Open
Abstract
UNLABELLED We recently discovered that desmoglein 2 (DSG2) is a receptor for human adenovirus species B serotypes Ad3, Ad7, Ad11, and Ad14. Ad3 is considered to be a widely distributed human pathogen. Ad3 binding to DSG2 triggers the transient opening of epithelial junctions. Here, we further delineate the mechanism that leads to DSG2-mediated epithelial junction opening in cells exposed to Ad3 and recombinant Ad3 fiber proteins. We identified an Ad3 fiber knob-dependent pathway that involves the phosphorylation of mitogen-activated protein (MAP) kinases triggering the activation of the matrix-metalloproteinase ADAM17. ADAM17, in turn, cleaves the extracellular domain of DSG2 that links epithelial cells together. The shed DSG2 domain can be detected in cell culture supernatant and also in serum of mice with established human xenograft tumors. We then extended our studies to Ad14 and Ad14P1. Ad14 is an important research and clinical object because of the recent appearance of a new, more pathogenic strain (Ad14P1). In a human epithelial cancer xenograft model, Ad14P1 showed more efficient viral spread and oncolysis than Ad14. Here, we tested the hypothesis that a mutation in the Ad14P1 fiber knob could account for the differences between the two strains. While our X-ray crystallography studies suggested an altered three-dimensional (3D) structure of the Ad14P1 fiber knob in the F-G loop region, this did not significantly change the fiber knob affinity to DSG2 or the intracellular signaling and DSG2 shedding in epithelial cancer cells. IMPORTANCE A number of widely distributed adenoviruses use the epithelial junction protein DSG2 as a receptor for infection and lateral spread. Interaction with DSG2 allows the virus not only to enter cells but also to open epithelial junctions which form a physical barrier to virus spread. Our study elucidates the mechanism beyond virus-triggered junction opening with a focus on adenovirus serotype 3. Ad3 binds to DSG2 with its fiber knob domain and triggers intracellular signaling that culminates in the cleavage of the extracellular domain of DSG2, thereby disrupting DSG2 homodimers between epithelial cells. We confirmed this pathway with a second DSG2-interacting serotype, Ad14, and its recently emerged strain Ad14P1. These new insights in basic adenovirus biology can be employed to develop novel drugs to treat adenovirus infection as well as be used as tools for gene delivery into epithelial tissues or epithelial tumors.
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22
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Grosche P, Sirockin F, Mac Sweeney A, Ramage P, Erbel P, Melkko S, Bernardi A, Hughes N, Ellis D, Combrink KD, Jarousse N, Altmann E. Structure-based design and optimization of potent inhibitors of the adenoviral protease. Bioorg Med Chem Lett 2015; 25:438-43. [DOI: 10.1016/j.bmcl.2014.12.057] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 11/29/2022]
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23
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Greber UF. How cells tune viral mechanics--insights from biophysical measurements of influenza virus. Biophys J 2015; 106:2317-21. [PMID: 24896110 DOI: 10.1016/j.bpj.2014.04.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 04/10/2014] [Accepted: 04/21/2014] [Indexed: 10/25/2022] Open
Abstract
During replication, the physical state of a virus is controlled by assembly and disassembly processes, when particles are put together and dismantled by cellular cues, respectively. A fundamental question has been how a cell can assemble an infectious virus, and dismantle a virus entering an uninfected cell and thereby trigger a new round of infection. This apparent paradox might be explained by considering that infected and uninfected cells are functionally different, or that assembly and disassembly take place along different cellular pathways. A third possibility is that the physical properties of newly assembled viruses are different from the infection-ready viruses. Recent biophysical experiments measured the stiffness of single Influenza viruses and combined this with biochemical measurements and cell biological assays. Besides inducing the fusogenic state of hemagglutinin, low pH cues softened the virus and precluded aggregation of viral ribonucleoprotein particles with the matrix protein M1. The recent experiments suggest a two-step model for Influenza virus entry and uncoating involving low pH in early and late endosomes, respectively. I conclude with a short outlook into how combined biophysical and cell biological approaches might lead to the identification of new cellular cues controlling viral uncoating and infection.
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Affiliation(s)
- Urs F Greber
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland.
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24
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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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Mac Sweeney A, Grosche P, Ellis D, Combrink K, Erbel P, Hughes N, Sirockin F, Melkko S, Bernardi A, Ramage P, Jarousse N, Altmann E. Discovery and structure-based optimization of adenain inhibitors. ACS Med Chem Lett 2014; 5:937-41. [PMID: 25147618 DOI: 10.1021/ml500224t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 06/20/2014] [Indexed: 02/07/2023] Open
Abstract
The cysteine protease adenain is the essential protease of adenovirus and, as such, represents a promising target for the treatment of ocular and other adenoviral infections. Through a concise two-pronged hit discovery approach we identified tetrapeptide nitrile 1 and pyrimidine nitrile 2 as complementary starting points for adenain inhibition. These hits enabled the first high-resolution X-ray cocrystal structures of adenain with inhibitors bound and revealed the binding mode of 1 and 2. The screening hits were optimized by a structure-guided medicinal chemistry strategy into low nanomolar drug-like inhibitors of adenain.
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Affiliation(s)
- Aengus Mac Sweeney
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Philipp Grosche
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - David Ellis
- Novartis Institute for Biomedical Research, 6201 South Freeway, Fort Worth, Texas 76134-2099, United States
| | - Keith Combrink
- Novartis Institute for Biomedical Research, 6201 South Freeway, Fort Worth, Texas 76134-2099, United States
| | - Paul Erbel
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Nicola Hughes
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Finton Sirockin
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Samu Melkko
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Anna Bernardi
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Paul Ramage
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
| | - Nadine Jarousse
- Novartis Institute for Biomedical Research, 4560 Horton Street, Emeryville, California 94608-2916, United States
| | - Eva Altmann
- Novartis Institute for Biomedical Research, Novartis Campus, CH-4002 Basel, Switzerland
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Penton-dodecahedral particles trigger opening of intercellular junctions and facilitate viral spread during adenovirus serotype 3 infection of epithelial cells. PLoS Pathog 2013; 9:e1003718. [PMID: 24204268 PMCID: PMC3814681 DOI: 10.1371/journal.ppat.1003718] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 09/04/2013] [Indexed: 11/19/2022] Open
Abstract
Human adenovirus serotypes Ad3, Ad7, Ad11, and Ad14 use the epithelial junction protein desmoglein 2 (DSG2) as a receptor for infection. During Ad infection, the fiber and penton base capsid proteins are produced in vast excess and form hetero-oligomers, called pentons. It has been shown for Ad3 that pentons self-assemble into penton-dodecahedra (PtDd). Our previous studies with recombinant purified Ad3 PtDd (produced in insect cells) showed that PtDd bind to DSG2 and trigger intracellular signaling resulting in the transient opening of junctions between epithelial cells. So far, a definitive proof for a function of Ad3 PtDd in the viral life cycle is elusive. Based on the recently published 3D structure of recombinant Ad3 PtDd, we generated a penton base mutant Ad3 vector (mu-Ad3GFP). mu-Ad3GFP is identical to its wild-type counterpart (wt-Ad3GFP) in the efficiency of progeny virus production; however, it is disabled in the production of PtDd. For infection studies we used polarized epithelial cancer cells or cell spheroids. We showed that in wt-Ad3GFP infected cultures, PtDd were released from cells before viral cytolysis and triggered the restructuring of epithelial junctions. This in turn facilitated lateral viral spread of de novo produced virions. These events were nearly absent in mu-Ad3GFP infected cultures. Our in vitro findings were consolidated in mice carrying xenograft tumors derived from human epithelial cancer cells. Furthermore, we provide first evidence that PtDd are also formed by another DSG2-interacting Ad serotype, the newly emerged, highly pathogenic Ad14 strain (Ad14p1). The central finding of this study is that a subgroup of Ads has evolved to generate PtDd as a strategy to achieve penetration into and dissemination in epithelial tissues. Our findings are relevant for basic and applied virology, specifically for cancer virotherapy. We have recently reported that a group of human Ads uses DSG2 as a receptor for infection. Among the DSG2-interacting Ads is serotype 3, which is widely distributed in the human population. During Ad3 infection, subviral particles (PtDd) formed by two capsid proteins are produced in vast excess and released early in infection. In this study, we demonstrate that PtDd trigger the opening of epithelial junctions and thus support the lateral spread of Ad3 progeny virus in epithelial tissues. Our study contributes to a better understanding of Ad3 infection and pathology. It also has implications for Ad-mediated gene transfer into epithelial tissues and tumors.
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27
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Blainey PC, Graziano V, Pérez-Berná AJ, McGrath WJ, Flint SJ, San Martín C, Xie XS, Mangel WF. Regulation of a viral proteinase by a peptide and DNA in one-dimensional space: IV. viral proteinase slides along DNA to locate and process its substrates. J Biol Chem 2012; 288:2092-102. [PMID: 23043138 DOI: 10.1074/jbc.m112.407460] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Precursor proteins used in the assembly of adenovirus virions must be processed by the virally encoded adenovirus proteinase (AVP) before the virus particle becomes infectious. An activated adenovirus proteinase, the AVP-pVIc complex, was shown to slide along viral DNA with an extremely fast one-dimensional diffusion constant, 21.0 ± 1.9 × 10(6) bp(2)/s. In principle, one-dimensional diffusion can provide a means for DNA-bound proteinases to locate and process DNA-bound substrates. Here, we show that this is correct. In vitro, AVP-pVIc complexes processed a purified virion precursor protein in a DNA-dependent reaction; in a quasi in vivo environment, heat-disrupted ts-1 virions, AVP-pVIc complexes processed five different precursor proteins in DNA-dependent reactions. Sliding of AVP-pVIc complexes along DNA illustrates a new biochemical mechanism by which a proteinase can locate its substrates, represents a new paradigm for virion maturation, and reveals a new way of exploiting the surface of DNA.
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Affiliation(s)
- Paul C Blainey
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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28
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Smoum R, Rubinstein A, Dembitsky VM, Srebnik M. Boron containing compounds as protease inhibitors. Chem Rev 2012; 112:4156-220. [PMID: 22519511 DOI: 10.1021/cr608202m] [Citation(s) in RCA: 298] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Reem Smoum
- The School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel.
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Transcriptional activation of the adenoviral genome is mediated by capsid protein VI. PLoS Pathog 2012; 8:e1002549. [PMID: 22427750 PMCID: PMC3303589 DOI: 10.1371/journal.ppat.1002549] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 01/10/2012] [Indexed: 12/12/2022] Open
Abstract
Gene expression of DNA viruses requires nuclear import of the viral genome. Human
Adenoviruses (Ads), like most DNA viruses, encode factors within early
transcription units promoting their own gene expression and counteracting
cellular antiviral defense mechanisms. The cellular transcriptional repressor
Daxx prevents viral gene expression through the assembly of repressive chromatin
remodeling complexes targeting incoming viral genomes. However, it has remained
unclear how initial transcriptional activation of the adenoviral genome is
achieved. Here we show that Daxx mediated repression of the immediate early Ad
E1A promoter is efficiently counteracted by the capsid protein VI. This requires
a conserved PPxY motif in protein VI. Capsid proteins from other DNA viruses
were also shown to activate the Ad E1A promoter independent of Ad gene
expression and support virus replication. Our results show how Ad entry is
connected to transcriptional activation of their genome in the nucleus. Our data
further suggest a common principle for genome activation of DNA viruses by
counteracting Daxx related repressive mechanisms through virion proteins. To initiate infection, DNA viruses deliver their genome to the nucleus and
express viral genes required for genome replication. Efficient transport is
achieved by packing the viral genome as a condensed, transcriptionally inactive
nucleo-protein complex. However, for most DNA viruses, including Adenoviruses
(Ads), it remains unclear how the viral genome is decondensed and how
transcription is initiated inside the nucleus. Cells control unwanted gene
expression by chromatin modification mediated through transcriptionally
repressive complexes. A key factor in repressive complex assemblies is the
transcriptional repressor Daxx. The Ad structural capsid protein VI is required
for endosomal escape and nuclear transport. Here we show that protein VI also
activates the Ad E1A promoter to initiate Ad gene expression. This is achieved
through the removal of Daxx repression from the E1A promoter, which requires a
conserved ubiquitin ligase interacting motif (PPxY-motif) in protein VI. We
further show that capsid proteins from other unrelated DNA viruses also activate
the Ad E1A promoter and support Ad replication by counteracting Daxx repression,
functionally replacing protein VI. Our data suggest that reversal of Daxx
repression by virion proteins is a widespread mechanism among DNA viruses that
is not restricted to a single virus family.
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Unity and diversity in the human adenoviruses: exploiting alternative entry pathways for gene therapy. Biochem J 2010; 431:321-36. [DOI: 10.1042/bj20100766] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Human Ads (adenoviruses) have been extensively utilized for the development of vectors for gene transfer, as they infect many cell types and do not integrate their genome into host-cell chromosomes. In addition, they have been widely studied as cytolytic viruses, termed oncolytic adenoviruses in cancer therapy. Ads are non-enveloped viruses with a linear double-stranded DNA genome of 30–38 kb which encodes 30–40 genes. At least 52 human Ad serotypes have been identified and classified into seven species, A–G. The Ad capsid has icosahedral symmetry and is composed of 252 capsomers, of which 240 are located on the facets of the capsid and consist of a trimeric hexon protein and the remaining 12 capsomers, the pentons, are at the vertices and comprise the penton base and projecting fibre protein. The entry of Ads into human cells is a two-step process. In the first step, the fibre protein mediates a primary interaction with the cell, effectively tethering the virus particle to the cell surface via a cellular attachment protein. The penton base then interacts with cell-surface integrins, leading to virus internalization. This interaction of the fibre protein with a number of cell-surface molecules appears to be important in determining the tropism of adenoviruses. Ads from all species, except species B and certain serotypes of species D, utilize CAR (coxsackie and adenovirus receptor) as their primary cellular-attachment protein, whereas most species B Ads use CD46, a complement regulatory protein. Such species-specific differences, as well as adaptations or modifications of Ads required for applications in gene therapy, form the major focus of the present review.
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Abstract
Of the 53 different human adenovirus (HAdV) serotypes belonging to species A-G, a significant number are associated with acute respiratory, gastrointestinal and ocular infections. Replication-defective HAdV-5-based vectors also continue to play a significant role in gene transfer trials and in vaccine delivery efforts in the clinic. Although significant progress has been made from studies of AdV biology, we still have an incomplete understanding of AdV's structure as well as its multifactorial interactions with the host. Continuing efforts to improve knowledge in these areas, as discussed in this chapter, will be crucial for revealing the mechanisms of AdV pathogenesis and for allowing optimal use of AdV vectors for biomedical applications.
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Affiliation(s)
- Jason G Smith
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA, 92037, USA
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Imelli N, Ruzsics Z, Puntener D, Gastaldelli M, Greber UF. Genetic reconstitution of the human adenovirus type 2 temperature-sensitive 1 mutant defective in endosomal escape. Virol J 2009; 6:174. [PMID: 19860872 PMCID: PMC2771014 DOI: 10.1186/1743-422x-6-174] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 10/27/2009] [Indexed: 12/05/2022] Open
Abstract
Human Adenoviruses infect the upper and lower respiratory tracts, the urinary and digestive tracts, lymphoid systems and heart, and give rise to epidemic conjunctivitis. More than 51 human serotypes have been identified to-date, and classified into 6 species A-F. The species C Adenoviruses Ad2 and Ad5 (Ad2/5) cause upper and lower respiratory disease, but how viral structure relates to the selection of particular infectious uptake pathways is not known. An adenovirus mutant, Ad2-ts1 had been isolated upon chemical mutagenesis in the past, and shown to have unprocessed capsid proteins. Ad2-ts1 fails to package the viral protease L3/p23, and Ad2-ts1 virions do not efficiently escape from endosomes. It had been suggested that the C22187T point mutation leading to the substitution of the conserved proline 137 to leucine (P137L) in the L3/p23 protease was at least in part responsible for this phenotype. To clarify if the C22187T mutation is necessary and sufficient for the Ad2-ts1 phenotype, we sequenced the genes encoding the structural proteins of Ad2-ts1, and confirmed that the Ad2-ts1 DNA carries the point mutation C22187T. Introduction of C22187T to the wild-type Ad2 genome in a bacterial artificial chromosome (Ad2-BAC) gave Ad2-BAC46 virions with the full Ad2-ts1 phenotype. Reversion of Ad2-BAC46 gave wild-type Ad2 particles indicating that P137L is necessary and sufficient for the Ad2-ts1 phenotype. The kinetics of Ad2-ts1 uptake into cells were comparable to Ad2 suggesting similar endocytic uptake mechanisms. Surprisingly, infectious Ad2 or Ad5 but not Ad2-ts1 uptake required CALM (clathrin assembly lymphoid myeloid protein), which controls clathrin-mediated endocytosis and membrane transport between endosomes and the trans-Golgi-network. The data show that no other mutations than P137L in the viral protease are necessary to give rise to particles that are defective in capsid processing and endosomal escape. This provides a basis for genetic analyses of distinct host requirements for Ad endocytosis and escape from endosomes.
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Affiliation(s)
- Nicola Imelli
- Institute of Zoology, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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33
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Adenovirus activates complement by distinctly different mechanisms in vitro and in vivo: indirect complement activation by virions in vivo. J Virol 2009; 83:5648-58. [PMID: 19321608 DOI: 10.1128/jvi.00082-09] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Understanding innate immunity is key to improving the safety of adenovirus (Ad) vectors for systemic gene therapy. Ad has been shown to activate complement in vitro, but activation of complement after Ad injection in vivo has not been directly measured. Using complement protein C3a as a marker of complement activation, we show that types 2 and 5 human Ads cause rapid complement activation after intravenous injection in mice. Unexpectedly, the mechanisms in vivo were different than those in vitro. Antibodies were critical for the activation of complement by Ad in vitro, but antibodies were not required in vivo. The classical pathway was required in vitro, whereas complement activation in vivo involved both classical and nonclassical pathways as well as the reticuloendothelial system. Remarkably, the entry-deficient Ad mutant ts1 was completely unable to activate complement in vivo even though it was fully able to activate complement in vitro. This result demonstrates that the complement system senses intravenously injected Ad primarily by detecting the effects of Ad on cells rather than through direct interaction of complement with virions. Encouragingly, shielding Ad with polyethylene glycol was effective at reducing complement activation both in vitro and in vivo. In summary, intravenously injected Ad rapidly activates complement through multiple pathways, but these pathways are different than those identified by in vitro studies. In vitro studies are poorly predictive of in vivo mechanisms because Ad virions activate complement through indirect mechanisms in vivo.
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Ethacrynic and alpha-lipoic acids inhibit vaccinia virus late gene expression. Antiviral Res 2008; 81:156-65. [PMID: 19061917 PMCID: PMC7114351 DOI: 10.1016/j.antiviral.2008.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 11/04/2008] [Accepted: 11/10/2008] [Indexed: 01/19/2023]
Abstract
Smallpox was declared eradicated in 1980. However recently, the need of agents effective against poxvirus infection has emerged again. In this paper, we report an original finding that two redox-modulating agents, the ethacrynic and α-lipoic acids (EA, LA), inhibit growth of vaccinia virus (VACV) in vitro. The effect of EA and LA was compared with those of β-mercaptoethanol, DTT and ascorbic acid, but these agents increased VACV growth in HeLa G cells. The inhibitory effects of EA and LA on the growth of VACV were further confirmed in several cell lines of different embryonic origin, in epithelial cells, fibroblasts, macrophages and T-lymphocytes. Finally, we have analyzed the mechanism of action of the two agents. They both decreased expression of VACV late genes, as demonstrated by western blot analysis and activity of luciferase expressed under control of different VACV promoters. In contrast, they did not inhibit virus entry into the cell, expression of VACV early genes or VACV DNA synthesis. The results suggest new directions in development of drugs effective against poxvirus infection.
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35
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Takahashi E, Cohen SL, Tsai PK, Sweeney JA. Quantitation of adenovirus type 5 empty capsids. Anal Biochem 2006; 349:208-17. [PMID: 16360111 DOI: 10.1016/j.ab.2005.11.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 11/03/2005] [Accepted: 11/04/2005] [Indexed: 11/20/2022]
Abstract
Adenovirus empty capsids are immature intermediates that lack DNA and viral core proteins. Highly purified preparations of empty and full capsids were generated by subjecting purified adenovirus preparations to repeated cesium chloride gradient separations. PAGE results revealed that empty capsids contain at least five bands that correspond to proteins absent from the mature virus proteome. Peptide mapping by matrix-assisted laser desorption/ionization time-of-flight MS revealed that three of these bands correspond to varying forms of L1 52/55kDa, a protein involved in the encapsidation of the viral DNA. One band at around 31kDa was found to include precursors to proteins VI and VIII. These precursors correspond to proteins that have not been cleaved by the adenovirus-encoded protease and are not present in the mature full capsids. The precursor to protein VIII (pVIII), a capsid cement protein, is used in this study as a marker in reverse-phased HPLC (RP-HPLC) analyses of adenovirus for the quantitation of empty capsids. A novel calculation method applied to the integration of RP-HPLC chromatograms allowed for the generation of a percentage empty capsid value in a given adenovirus preparation. The percentage empty capsid values generated to date by this method show a high degree of precision and good agreement with a cesium chloride gradient/SDS-PAGE quantitation method of empty capsids. The advantage of this method lies in the accurate, precise, and rapid generation of the percentage of empty capsids in a given purified virus preparation without relying on tedious and time-consuming cesium chloride gradient separations and extractions.
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Affiliation(s)
- Eddie Takahashi
- Bioprocess and Bioanalytical Research, Bioprocess R&D, Merck Research Laboratories, West Point, PA 19486, USA
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36
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Abdelrahman YM, Belland RJ. The chlamydial developmental cycle. FEMS Microbiol Rev 2005; 29:949-59. [PMID: 16043254 DOI: 10.1016/j.femsre.2005.03.002] [Citation(s) in RCA: 425] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2004] [Revised: 03/09/2005] [Accepted: 03/18/2005] [Indexed: 11/28/2022] Open
Abstract
Intracellular parasitism by bacterial pathogens is a complex, multi-factorial process that has been exploited successfully by a wide variety of organisms. Members of the Order Chlamydiales are obligate intracellular bacteria that are transmitted as metabolically inactive particles and must differentiate, replicate, and re-differentiate within the host cell to carry out their life cycle. Understanding the developmental cycle has been greatly advanced by the availability of complete genome sequences, DNA microarrays, and advanced cell biology techniques. Measuring transcriptional changes throughout the cycle has allowed investigators to determine the nature of the temporal gene expression changes required for bacterial growth and development.
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Affiliation(s)
- Yasser M Abdelrahman
- Department of Molecular Sciences, University of Tennessee Health Sciences Center, 858 Madison Avenue, Memphis, TN 38163, USA
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37
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Meier O, Gastaldelli M, Boucke K, Hemmi S, Greber UF. Early steps of clathrin-mediated endocytosis involved in phagosomal escape of Fcgamma receptor-targeted adenovirus. J Virol 2005; 79:2604-13. [PMID: 15681460 PMCID: PMC546601 DOI: 10.1128/jvi.79.4.2604-2613.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Adenovirus type 2 (Ad2) and Ad5 enter epithelial cells via the coxsackievirus B Ad receptor (CAR) and alpha(v) integrin coreceptors. In the absence of CAR, they can be directed to the Fcgamma receptor 1 of hematopoietic cells by an adaptor comprising the extracellular CAR domain and the Fc portion of a human immunoglobulin G (CARex-Fc). This gives rise to Ad aggregates and single particles which together enhance gene delivery up to 250-fold compared to adaptor-less viruses. A small interfering RNA knockdown of the clathrin heavy chain and quantitative electron microscopy of hematopoietic leukemia cells showed that the majority of Ads were phagocytosed as clusters of 1 to 3 microm in diameter and that about 10% of the particles entered cells by clathrin-mediated endocytosis. The clathrin knockdown did not affect phagocytosis but, surprisingly, inhibited viral escape from phagosomes. Similarly, blocking an early stage of clathrin-coated pit assembly inhibited phagosomal escape and infection but not aggregate uptake, unlike blocking of a late stage of clathrin-coated pit formation. We propose a cooperative interaction of clathrin-mediated endocytosis and phagocytosis triggering phagosomal lysis and infection.
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Affiliation(s)
- Oliver Meier
- Zoologisches Institut, University of Zürich, 8057 Zürich, Switzerland
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38
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Marsman WA, Buskens CJ, Wesseling JG, Van Lanschot JJB, Bosma PJ. Gene therapy for barrett's esophagus: adenoviral gene transfer in different intestinal models. Cancer Gene Ther 2005; 12:778-86. [PMID: 15877083 DOI: 10.1038/sj.cgt.7700841] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Adenoviral gene therapy could potentially be used for treatment of patients with a Barrett's esophagus. In order to study the feasibility of this approach it is important to study adenoviral intestinal transduction both in vitro and in vivo. In the present study, we used differentiating Caco-2 cells, closed intestinal loops and a Barrett's esophagus rat model to test transduction of adenoviruses expressing green fluorescent protein. We observed a decreased adenoviral transduction from 18.6 to 2.3% in undifferentiated and differentiated Caco-2 cells, respectively. This could be improved by the use of the mucolytic agent N-acetylcysteine (NAC) and the polycation diethylaminoethyl-dextran (DEAE-dextran), which improved transduction in differentiated cells five- and ten-fold, respectively. Also an RGD-retargeted adenovirus showed an improved transduction in differentiated cells. In closed intestinal loops adenoviral transduction was limited and the use of NAC and DEAE-dextran or RGD targeting had little effect. The Barrett's esophagus rat model consisted of an esophagojejunostomy, which results in a Barrett's esophagus and esophageal tumors within 6 months. Adenoviral transduction in this model was limited and mainly localized in the basal layer of normal esophagus and stromal tissue of a Barrett's segment. We conclude that although the adenovirus shows promising results in vitro, the current adenoviral vectors are probably not suitable for patients with Barrett's esophagus.
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Affiliation(s)
- Willem A Marsman
- AMC Liver Center, Academic Medical Center, Amsterdam, The Netherlands.
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39
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Campos SK, Parrott MB, Barry MA. Avidin-based targeting and purification of a protein IX-modified, metabolically biotinylated adenoviral vector. Mol Ther 2005; 9:942-54. [PMID: 15194061 PMCID: PMC4308313 DOI: 10.1016/j.ymthe.2004.03.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2004] [Accepted: 03/07/2004] [Indexed: 10/26/2022] Open
Abstract
While genetic modification of adenoviral vectors can produce vectors with modified tropism, incorporation of targeting peptides/proteins into the structural context of the virion can also result in destruction of ligand targeting or virion integrity. To combat this problem, we have developed a versatile targeting system using metabolically biotinylated adenoviral vectors bearing biotinylated fiber proteins. These vectors have been demonstrated to be useful as a platform for avidin-based ligand screening and vector targeting by conjugating biotinylated ligands to the virus using high-affinity tetrameric avidin (K(d) = 10(-15) M). The biotinylated vector could also be purified by biotin-reversible binding on monomeric avidin (K(d) = 10(-7) M). In this report, a second metabolically biotinylated adenovirus vector, Ad-IX-BAP, has been engineered by fusing a biotin acceptor peptide (BAP) to the C-terminus of the adenovirus pIX protein. This biotinylated vector displays twice as many biotins and was markedly superior for single-step affinity purification on monomeric avidin resin. However, unlike the fiber-biotinylated vector, Ad-IX-BAP failed to retarget to cells with biotinylated antibodies including anti-CD71 against the transferrin receptor. In contrast, Ad-IX-BAP was retargeted if transferrin, the cognate ligand for CD71, was used as a ligand rather than the anti-CD71. This work demonstrates the utility of metabolic biotinylation as a molecular screening tool to assess the utility of different viral capsid proteins for ligand display and the biology and compatibility of different ligands and receptors for vector targeting applications. These results also demonstrate the utility of the pIX-biotinylated vector as a platform for gentle single-step affinity purification of adenoviral vectors.
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Affiliation(s)
- Samuel K. Campos
- Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
| | - M. Brandon Parrott
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Immunology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Michael A. Barry
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Immunology, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
- To whom correspondence and reprint requests should be addressed at One Baylor Plaza, BCM505, Houston, TX 77030. Fax: +(713) 798-1481.
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40
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Honkavuori KS, Pollard BD, Rodriguez MS, Hay RT, Kemp GD. Dual role of the adenovirus pVI C terminus as a nuclear localization signal and activator of the viral protease. J Gen Virol 2004; 85:3367-3376. [PMID: 15483253 DOI: 10.1099/vir.0.80203-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adenain, the protease produced by adenovirus, is regulated by formation of a heterodimer with an 11 aa peptide derived from the C terminus of another adenoviral protein, pVI. Here, the role of the basic motif KRRR, which is conserved in pVI sequences from human adenovirus serotypes, was investigated. It was shown that this motif is less important than the N- or C-terminal regions in the formation of the adenain–peptide heterodimer and in the activity of the subsequent complex. This motif, however, acted as a nuclear localization signal that was capable of targeting heterologous proteins to the nucleus, resulting in a distinctive intranuclear distribution consisting of discrete foci, which is similar to that found for pVI during adenovirus infection.
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Affiliation(s)
- K S Honkavuori
- Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - B D Pollard
- Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - M S Rodriguez
- Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - R T Hay
- Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
| | - G D Kemp
- Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK
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41
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Haruki H, Gyurcsik B, Okuwaki M, Nagata K. Ternary complex formation between DNA-adenovirus core protein VII and TAF-Ibeta/SET, an acidic molecular chaperone. FEBS Lett 2004; 555:521-7. [PMID: 14675767 DOI: 10.1016/s0014-5793(03)01336-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The adenovirus (Ad) genome complexed with viral core proteins designated Ad core is the template for transcription of early genes and the first round of replication in Ad-infected cells. A cellular protein designated template-activating factor-I (TAF-I) is found to be involved in remodeling of the Ad core in vitro. Here we found that TAF-I interacts with the Ad DNA through core protein VII in infected cells in early phases of infection. In vitro binding assays using recombinant proteins showed that TAF-I forms ternary complexes with DNA-protein VII complexes.
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Affiliation(s)
- Hirohito Haruki
- Department of Infection Biology, Institute of Basic Medical Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
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42
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Russell IA, Royds JA, Braithwaite AW. Exploitation of Cell Cycle and Cell Death Controls by Adenoviruses: The Road to a Productive Infection. VIRUSES AND APOPTOSIS 2004; 36:207-43. [PMID: 15171614 DOI: 10.1007/978-3-540-74264-7_11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- I Alasdair Russell
- Cell Transformation Group, Department of Pathology, Dunedin School of Medicine, University of Otago, Box 913, Dunedin, New Zealand
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43
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Abstract
Key proteins of the icosahedral-shaped adenovirus (Ad) capsid mediate infection, and interact with cellular proteins to coordinate stepwise events of cell entry that produce successful gene transfer. Infection is mediated predominantly by the penton and fiber capsid proteins. The fiber initiates cell binding while the penton binds integrin coreceptors, triggering integrin-mediated endocytosis. Penton integrin signaling precedes viral escape from the endosomal vesicle. After cell binding, the virus undergoes stepwise disassembly of the capsid, shedding proteins during cell entry. Intracellular trafficking of the remaining capsid shell is mediated by the interaction of naked particles with the cytoskeleton. The capsid translocates toward the nucleus, with the majority of capsid proteins accumulating at the nuclear periphery, while viral DNA and associated protein VII are extruded through the nuclear pore. This discussion will encompass the current knowledge on Ad cell entry and trafficking, with an emphasis on the contribution of Ad capsid proteins to these processes. A greater understanding of the highly effective Ad cell entry pathway may lend itself to the development of safer drug and gene delivery alternatives utilizing similar pathways.
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Affiliation(s)
- Lali K Medina-Kauwe
- Department of Biochemistry and Molecular Biology, University of Southern California Keck School of Medicine, Institute for Genetic Medicine, 2250 Alcazar Street, CSC240, Los Angeles, CA 90033, USA.
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44
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Belland RJ, Zhong G, Crane DD, Hogan D, Sturdevant D, Sharma J, Beatty WL, Caldwell HD. Genomic transcriptional profiling of the developmental cycle of Chlamydia trachomatis. Proc Natl Acad Sci U S A 2003; 100:8478-83. [PMID: 12815105 PMCID: PMC166254 DOI: 10.1073/pnas.1331135100] [Citation(s) in RCA: 370] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chlamydia trachomatis is one of the most common bacterial pathogens and is the etiological agent of debilitating sexually transmitted and ocular diseases in humans. The organism is an obligate intracellular prokaryote characterized by a highly specialized biphasic developmental cycle. We have performed genomic transcriptional analysis of the chlamydial developmental cycle. This approach has led to the identification of a small subset of genes that control the primary (immediate-early genes) and secondary (late genes) differentiation stages of the cycle. Immediate-early gene products initiate bacterial metabolism and potentially modify the bacterial phagosome to escape fusion with lysosomes. One immediate early gene (CT147) is a homolog of the human early endosomal antigen-1 that is localized to the chlamydial phagosome; suggesting a functional role for CT147 in establishing the parasitophorous vacuole in a nonfusogenic pathway. Late gene products terminate bacterial cell division and constitute structural components and remodeling activities involved in the formation of the highly disulfide cross-linked outer-membrane complex that functions in attachment and invasion of new host cells. Many of the genes expressed during the immediate-early and late differentiation stages are Chlamydia-specific and have evolutionary origins in eukaryotic lineages.
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Affiliation(s)
- Robert J Belland
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, MT 59840, USA.
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45
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Trotman LC, Achermann DP, Keller S, Straub M, Greber UF. Non-classical export of an adenovirus structural protein. Traffic 2003; 4:390-402. [PMID: 12753648 DOI: 10.1034/j.1600-0854.2003.00094.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The icosahedral capsids of Adenoviruses (Ads) consist of the hexon and stabilizing proteins building the facettes, and of the vertex protein penton base (Pb) anchoring the protruding fibers. The fibers bind to the Coxsackie virus B Ad cell surface receptor (CAR) and Pb to integrins. Here we describe a novel property of the Ad2 Pb. Pb was found to leave the infected cell and, upon exit, it attached to the surrounding noninfected cells forming a radial gradient with highest Pb levels on cells adjacent to the infected cell. The producer cells remained intact until at least 30 h post infection. At this point, Pb was not recovered from the extracellular medium, suggesting that its cell-cell spread might not involve free Pb. When viral particles were released at late stages of infection, soluble Pb was found in the extracellular medium and it randomly bound to noninfected cells. Nonlytic export of Pb occurred upon transient transfection with plasmid DNA, but plasmid-encoded fiber was not exported, indicating that cell-cell spread of Pb is autonomous of infection. Pb export was not affected by Brefeldin A-induced disruption of the Golgi apparatus, suggesting that it occurred via a nonclassical mechanism. Interestingly, the coexpression of Pb and fiber leads to both Pb and fiber export, termed 'protein abduction'. We suggest that fiber abduction might support viral dissemination in infected tissues by interfering with tissue integrity.
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Affiliation(s)
- Lloyd C Trotman
- Zoologisches Institut der Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
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46
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Abstract
Pathogen entry into cells occurs by direct penetration of the plasma membrane, clathrin-mediated endocytosis, caveolar endocytosis, pinocytosis or macropinocytosis. For a particular agent, the infectious pathways are typically restricted, reflecting a tight relationship with the host. Here, we survey the uptake process of human adenovirus (Ad) type 2 and 5 and integrate it into the cell biology of endocytosis. Ad2 and Ad5 naturally infect respiratory epithelial cells. They bind to a primary receptor, the coxsackie virus B Ad receptor (CAR). The CAR-docked particles activate integrin coreceptors and this triggers a variety of cell responses, including endocytosis. Ad2/Ad5 endocytosis is clathrin-mediated and involves the large GTPase dynamin and the adaptor protein 2. A second endocytic process is induced simultaneously with viral uptake, macropinocytosis. Together, these pathways are associated with viral infection. Macropinocytosis requires integrins, F-actin, protein kinase C and small G-proteins of the Rho family, but not dynamin. Macropinocytosis per se is not required for viral uptake into epithelial cells, but it appears to be a productive entry pathway of Ad artificially targeted to the high-affinity Fcgamma receptor CD64 of hematopoietic cells lacking CAR. In epithelial and hematopoietic cells, the macropinosomal contents are released to the cytosol. This requires viral signalling from the surface and coincides with particle escape from endosomes and infection. It emerges that incoming Ad2 and Ad5 distinctly modulate the endocytic trafficking and disrupt selective cellular compartments. These features can be exploited for effective artificial targeting of Ad vectors to cell types of interest.
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Affiliation(s)
- Oliver Meier
- Zoologisches Institut der Universität Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
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Ashbourne Excoffon KJD, Moninger T, Zabner J. The coxsackie B virus and adenovirus receptor resides in a distinct membrane microdomain. J Virol 2003; 77:2559-67. [PMID: 12551994 PMCID: PMC141093 DOI: 10.1128/jvi.77.4.2559-2567.2003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The coxsackie B virus and adenovirus receptor (CAR) is a member of the immunoglobulin superfamily. In addition to activity as a viral receptor, it may play a role in cellular adhesion. We asked what determines the cell membrane microdomain of CAR. We found that CAR is localized to a novel lipid-rich microdomain similar to that of the low-density lipoprotein receptor (LDLR) but distinct from that of a CAR variant that exhibited traditional lipid raft localization via fusion to a glycosylphosphatidylinositol (GPI) tail. The cytoplasmic tail determines its membrane localization, since deletion of this domain resulted in mislocalization. Results indicate that CAR, CAR-LDLR, and LDLR reside in a novel lipid raft that is distinct from caveolin-1-containing caveolae and GPI-linked proteins. Residence in a lipid-rich domain provides a mechanism that allows CAR to interact with other cell adhesion proteins and yet function as an adenovirus receptor.
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48
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Chandran K, Farsetta DL, Nibert ML. Strategy for nonenveloped virus entry: a hydrophobic conformer of the reovirus membrane penetration protein micro 1 mediates membrane disruption. J Virol 2002; 76:9920-33. [PMID: 12208969 PMCID: PMC136509 DOI: 10.1128/jvi.76.19.9920-9933.2002] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanisms employed by nonenveloped animal viruses to penetrate the membranes of their host cells remain enigmatic. Membrane penetration by the nonenveloped mammalian reoviruses is believed to deliver a partially uncoated, but still large ( approximately 70-nm), particle with active transcriptases for viral mRNA synthesis directly into the cytoplasm. This process is likely initiated by a particle form that resembles infectious subvirion particles (ISVPs), disassembly intermediates produced from virions by proteolytic uncoating. Consistent with that idea, ISVPs, but not virions, can induce disruption of membranes in vitro. Both activities ascribed to ISVP-like particles, membrane disruption in vitro and membrane penetration within cells, are linked to N-myristoylated outer-capsid protein micro 1, present in 600 copies at the surfaces of ISVPs. To understand how micro 1 fulfills its role as the reovirus penetration protein, we monitored changes in ISVPs during the permeabilization of red blood cells induced by these particles. Hemolysis was preceded by a major structural transition in ISVPs, characterized by conformational change in micro 1 and elution of fibrous attachment protein sigma 1. The altered conformer of micro 1 was required for hemolysis and was markedly hydrophobic. The structural transition in ISVPs was further accompanied by derepression of genome-dependent mRNA synthesis by the particle-associated transcriptases. We propose a model for reovirus entry in which (i) primed and triggered conformational changes, analogous to those in enveloped-virus fusion proteins, generate a hydrophobic micro 1 conformer capable of inserting into and disrupting cell membranes and (ii) activation of the viral particles for membrane interaction and mRNA synthesis are concurrent events. Reoviruses provide an opportune system for defining the molecular details of membrane penetration by a large nonenveloped animal virus.
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Affiliation(s)
- Kartik Chandran
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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49
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Abstract
The adenovirus protease, adenain is functionally required for virion uncoating and virion maturation and release from the infected cell. In addition to hydrolysis of precursor proteins at specific consensus sites, adenain has also been observed to cleave viral proteins at other sites. Here we re-examine the sequences in the consensus sites and also the phenomena of cleavage at other sites on viral proteins II, 100K, V, VI and VII. An examination of the eight residues flanking the scissile bond in 274 consensus sites from 36 different adenovirus serotypes in the DNA sequence databanks provided the following main conclusions: (1) two types of consensus sites, type 1, (M,I,L)XGX-G and type 2, (M,I,L)XGG-X, (2) the variant positions P(3) and P(1) never contained C,P,D,H,W,Y and C,P,G,M amino acids, respectively in type 1, (3) the variant positions P(3) and P(1)' never contained C,D,L,W and C,P,D,Q,H,Y,W amino acids, respectively in type 2, and (4) the thiol forming C residue occurred only twice within the eight residues flanking the scissile bond and that in the P(4)' position. Six unusual serotypes had (M,L,I)XAT-G as the PVII consensus site. Adenain has been proposed to cleave protein VI at an unknown site in the course of virion uncoating. The cleavage of capsid protein VI in the absence of a consensus site is confirmed here in vitro using recombinant adenain. Virion proteins II, V and VII and the nonstructural protein 100K were also digested in vitro into discrete fragments by recombinant adenain. We conclude that adenain preferentially cleaves viral proteins at their consensus sites, but is capable, in vitro of cleavages at other discrete sites which resemble the consensus cleavage sites.
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Affiliation(s)
- Angelique Ruzindana-Umunyana
- Département de Microbiologie et d'Infectiologie, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Québec, Canada J1H 5N4
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Jornot L, Morris MA, Petersen H, Moix I, Rochat T. N-acetylcysteine augments adenovirus-mediated gene expression in human endothelial cells by enhancing transgene transcription and virus entry. J Gene Med 2002; 4:54-65. [PMID: 11828388 DOI: 10.1002/jgm.232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND It has previously been shown that oxidants reduce the efficiency of adenoviral transduction in human umbilical vein endothelial cells (HUVECs). In this study, the effect of the antioxidant N-acetylcysteine (NAC) in adenovirus-mediated gene transfer has been investigated. METHODS HUVECs were pretreated or not with NAC, and infected with E1E3-deleted adenovirus (Ad) containing the LacZ gene expressed from the RSV-LTR promoter/enhancer in the presence and absence of NAC. Transgene expression was assessed at the protein level (histochemical staining, measurement of beta-Gal activity, and western blot), mRNA level (real-time RT-PCR) and gene level (nuclear run on) 24 h and 48 h after infection. Adenoviral DNA was quantitated by real-time PCR, and cell surface expression of Coxsackie/adenovirus receptors (CAR) was determined by FACS analysis. RESULTS Pretreatment of cells with NAC prior to Ad infection enhanced beta-Gal activity by two-fold due to an increase in viral DNA, which was related to increased CAR expression. When NAC was present only during the post-infection period, a five-fold increase in beta-Gal activity and LacZ gene transcriptional activity was observed. When NAC was present during both the pretreatment and the post-infection period, beta-Gal activity was further enhanced, by 15-fold. Augmentation of beta-Gal activity was paralleled by an increase in beta-Gal protein and mRNA levels. NAC did not affect the half-life of LacZ mRNA. CONCLUSION Pretreatment with NAC prior to Ad infection enhances virus entry, while treatment with NAC post-infection increases transgene transcription. This strategy permits the use of lower adenoviral loads and thus might be helpful for gene therapy of vascular diseases.
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Affiliation(s)
- L Jornot
- Respiratory Division, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
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