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Adsero A, Chestnut B, Shahnejat-Bushehri S, Sasnoor L, McMurphy T, Swenor M, Pasquino R, Pradhan A, Hernandez V, Padegimas L, Dismuke D. A Novel Role for the Adenovirus L4 Region 22K and 33K Proteins in Adeno-Associated Virus Production. Hum Gene Ther 2024; 35:59-69. [PMID: 38062776 PMCID: PMC10818037 DOI: 10.1089/hum.2023.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 11/26/2023] [Indexed: 01/18/2024] Open
Abstract
Despite decades of research in adeno-associated virus (AAV) and the role of adenovirus in production, the interplay of AAV and adenovirus is not fully understood. Specific regions of the adenoviral genome containing E1, E2a, E4 open reading frame (ORF), and VA RNA have been demonstrated as necessary for AAV production; however, incorporating these regions into either a producer cell line or subcloning into an Ad helper plasmid may lead to inclusion of neighboring adenoviral sequence or ORFs with unknown function. Because AAV is frequently used in gene therapies, removing excessive adenovirus sequences improves the Ad helper plasmid size and manufacturability, and may lead to safer vectors for patients. Furthermore, deepening our understanding of the helper virus genes required for recombinant AAV (rAAV) production has the potential to increase yields and manufacturability of rAAV for clinical and commercial applications. One region continuously included in various Ad helper plasmid iterations is the adenoviral E2a promoter region that appears to be necessary for E2a expression. Due to the compact nature of viral genomes, the E2a promoter region overlaps with the Hexon Assembly/100K protein and the L4 region. The L4 region, which contains the coding sequences for 22K and 33K proteins, had not been thought to be necessary for AAV production. Through molecular techniques, this study demonstrates that the adenoviral 22K protein is essential for rAAV production in HEK293 cells by triple transfection and that the 33K protein synergistically increases rAAV yield.
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Affiliation(s)
- Angela Adsero
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
| | | | | | - Lalita Sasnoor
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
| | - Travis McMurphy
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
| | - Mike Swenor
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
- Process Development, Forge Biologics, Grove City, Ohio, USA
| | - Ryan Pasquino
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
| | - Arun Pradhan
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
| | | | - Linas Padegimas
- Molecular Development, Forge Biologics, Grove City, Ohio, USA
| | - David Dismuke
- Chief Technical Officer, Forge Biologics, Grove City, Ohio, USA
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2
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Su W, Seymour LW, Cawood R. AAV production in stable packaging cells requires expression of adenovirus 22/33K protein to allow episomal amplification of integrated rep/cap genes. Sci Rep 2023; 13:21670. [PMID: 38066084 PMCID: PMC10709602 DOI: 10.1038/s41598-023-48901-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 11/30/2023] [Indexed: 12/18/2023] Open
Abstract
Efficient manufacture of recombinant adeno-associated virus (rAAV) vectors for gene therapy remains challenging. Packaging cell lines containing stable integration of the AAV rep/cap genes have been explored, however rAAV production needs to be induced using wild-type adenoviruses to promote episomal amplification of the integrated rep/cap genes by mobilizing a cis-acting replication element (CARE). The adenovirus proteins responsible are not fully defined, and using adenovirus during rAAV manufacture leads to contamination of the rAAV preparation. 'TESSA' is a helper adenovirus with a self-repressing Major Late Promoter (MLP). Its helper functions enable efficient rAAV manufacture when the rep and cap genes are provided in trans but is unable to support rAAV production from stable packaging cells. Using rAAV-packaging cell line HeLaRC32, we show that expression of the adenovirus L4 22/33K unit is essential for rep/cap amplification but the proteins are titrated away by binding to replicating adenovirus genomes. siRNA-knockdown of the adenovirus DNA polymerase or the use of a thermosensitive TESSA mutant decreased adenovirus genome replication whilst maintaining MLP repression, thereby recovering rep/cap amplification and efficient rAAV manufacture. Our findings have direct implications for engineering more efficient adenovirus helpers and superior rAAV packaging/producer cells.
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Affiliation(s)
- Weiheng Su
- Department of Oncology, University of Oxford, Old Road Campus, Oxford, OX3 7DQ, UK.
- OXGENE Ltd, Oxford Science Park, Oxford, OX4 4GA, UK.
| | - Leonard W Seymour
- Department of Oncology, University of Oxford, Old Road Campus, Oxford, OX3 7DQ, UK
| | - Ryan Cawood
- OXGENE Ltd, Oxford Science Park, Oxford, OX4 4GA, UK
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3
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Evseev P, Gutnik D, Shneider M, Miroshnikov K. Use of an Integrated Approach Involving AlphaFold Predictions for the Evolutionary Taxonomy of Duplodnaviria Viruses. Biomolecules 2023; 13:biom13010110. [PMID: 36671495 PMCID: PMC9855967 DOI: 10.3390/biom13010110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 12/31/2022] [Accepted: 01/01/2023] [Indexed: 01/06/2023] Open
Abstract
The evaluation of the evolutionary relationships is exceptionally important for the taxonomy of viruses, which is a rapidly expanding area of research. The classification of viral groups belonging to the realm Duplodnaviria, which include tailed bacteriophages, head-tailed archaeal viruses and herpesviruses, has undergone many changes in recent years and continues to improve. One of the challenging tasks of Duplodnaviria taxonomy is the classification of high-ranked taxa, including families and orders. At the moment, only 17 of 50 families have been assigned to orders. The evaluation of the evolutionary relationships between viruses is complicated by the high level of divergence of viral proteins. However, the development of structure prediction algorithms, including the award-winning AlphaFold, encourages the use of the results of structural predictions to clarify the evolutionary history of viral proteins. In this study, the evolutionary relationships of two conserved viral proteins, the major capsid protein and terminase, representing different viruses, including all classified Duplodnaviria families, have been analysed using AlphaFold modelling. This analysis has been undertaken using structural comparisons and different phylogenetic methods. The results of the analyses mainly indicated the high quality of AlphaFold modelling and the possibility of using the AlphaFold predictions, together with other methods, for the reconstruction of the evolutionary relationships between distant viral groups. Based on the results of this integrated approach, assumptions have been made about refining the taxonomic classification of bacterial and archaeal Duplodnaviria groups, and problems relating to the taxonomic classification of Duplodnaviria have been discussed.
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Affiliation(s)
- Peter Evseev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
- Correspondence: (P.E.); (K.M.)
| | - Daria Gutnik
- Limnological Institute, Siberian Branch of the Russian Academy of Sciences, 664033 Irkutsk, Russia
| | - Mikhail Shneider
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
| | - Konstantin Miroshnikov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Str., 117997 Moscow, Russia
- Correspondence: (P.E.); (K.M.)
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4
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Das R, Bajpai U. Functional characterization of a DNA-dependent AAA ATPase in a F-cluster mycobacteriophage. Virus Res 2023; 323:198957. [PMID: 36209922 PMCID: PMC10194130 DOI: 10.1016/j.virusres.2022.198957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/06/2022] [Accepted: 10/03/2022] [Indexed: 11/05/2022]
Abstract
Mycobacteriophages are viruses of Mycobacterium spp. with promising diagnostic and therapeutic potential. Phage genome exploration and characterization of their proteomes are essential to gaining a better understanding of their role in phage biology. So far, genomes of about 2113 mycobacteriophages have been defined and from among those, 1563 phage protein families (phamilies) are identified. However, the function of only a fraction (about 15%) is known since a majority of ORFs in phage genomes are hypothetical proteins. In this study, we have analyzed Gp65 (AQT25877.1), a putative AAA ATPase (Pham 9410) from a F1 cluster mycobacteriophage SimranZ1 (KY385384.1). Though homology analysis of Gp65-AAA ATPase showed the presence of this gene in 38 mycobacteriophages of the F1 cluster, however its further analysis has not been reported yet in any study. The sequence-based functional annotation predicted Gp65 to belong to the P-loop NTPase superfamily and to have AAA_24 and RecA/RadA domains, which are known to be involved in ATP-dependent DNA recombination/repair/maintenance mechanisms. Molecular docking of Gp65 with ATP identified Gly21 and Ser23 residues to be involved in the specific binding. The experimental validation of the DNA-dependent ATPase activity of Gp65 was done using a microtiter plate assay, where the ATPase activity was observed to increase in the presence of dsDNA. The structural characteristics of the protein are demonstrated by non-denaturing gel electrophoresis, showing Gp65 to exist in oligomeric states, which was confirmed by transmission electron microscopy (TEM). It was revealed to exist as a hexamer with a prominent central pore. In this study, based on the stated structural and functional characterization, we report the AAA ATPase to have a putative role in DNA recombination/repair/maintenance mechanism in mycobacteriophages.
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Affiliation(s)
- Ritam Das
- Department of Life Science, Acharya Narendra Dev College, University of Delhi, Govindpuri, New Delhi 110019, India
| | - Urmi Bajpai
- Department of Biomedical Science, Acharya Narendra Dev College, University of Delhi, Govindpuri, Kalkaji, New Delhi 110019, India.
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5
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de Pablo PJ, San Martín C. Seeing and touching adenovirus: complementary approaches for understanding assembly and disassembly of a complex virion. Curr Opin Virol 2021; 52:112-122. [PMID: 34906758 DOI: 10.1016/j.coviro.2021.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 12/24/2022]
Abstract
Understanding adenovirus assembly and disassembly poses many challenges due to the virion complexity. A distinctive feature of adenoviruses is the large amount of virus-encoded proteins packed together with the dsDNA genome. Cryo-electron microscopy (cryo-EM) structures are broadening our understanding of capsid variability along evolution, but little is known about the organization of the non-icosahedral nucleoproteic core and its influence in adenovirus function. Atomic force microscopy (AFM) probes the biomechanics of virus particles, while simultaneously inducing and monitoring their disassembly in real time. Synergistic combination of AFM with EM shows that core proteins play unexpected key roles in maturation and entry, and uncoating dynamics are finely tuned to ensure genome release at the appropriate time and place for successful infection.
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Affiliation(s)
- Pedro J de Pablo
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid and IFIMAC, 28049 Madrid, Spain.
| | - Carmen San Martín
- Departamento de Estructura de Macromoléculas, Centro Nacional de Biotecnología (CNB-CSIC), Darwin 3, 28049 Madrid, Spain.
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6
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Kulanayake S, Tikoo SK. Adenovirus Core Proteins: Structure and Function. Viruses 2021; 13:v13030388. [PMID: 33671079 PMCID: PMC7998265 DOI: 10.3390/v13030388] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 02/19/2021] [Accepted: 02/24/2021] [Indexed: 01/04/2023] Open
Abstract
Adenoviruses have served as a model for investigating viral-cell interactions and discovering different cellular processes, such as RNA splicing and DNA replication. In addition, the development and evaluation of adenoviruses as the viral vectors for vaccination and gene therapy has led to detailed investigations about adenovirus biology, including the structure and function of the adenovirus encoded proteins. While the determination of the structure and function of the viral capsid proteins in adenovirus biology has been the subject of numerous reports, the last few years have seen increased interest in elucidating the structure and function of the adenovirus core proteins. Here, we provide a review of research about the structure and function of the adenovirus core proteins in adenovirus biology.
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Affiliation(s)
- Shermila Kulanayake
- Vaccine and Infectious Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, Saskatoon, SK S7N5E3, Canada;
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N5E3, Canada
| | - Suresh K. Tikoo
- Vaccine and Infectious Disease Organization-International Vaccine Center (VIDO-InterVac), University of Saskatchewan, Saskatoon, SK S7N5E3, Canada;
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N5E3, Canada
- Correspondence:
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7
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Genoveso MJ, Hisaoka M, Komatsu T, Wodrich H, Nagata K, Okuwaki M. Formation of adenovirus DNA replication compartments and viral DNA accumulation sites by host chromatin regulatory proteins including NPM1. FEBS J 2019; 287:205-217. [PMID: 31365788 DOI: 10.1111/febs.15027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 06/19/2019] [Accepted: 07/29/2019] [Indexed: 01/08/2023]
Abstract
The adenovirus (Ad) genome is believed to be packaged into the virion by forming a chromatin-like structure. The replicated viral genome is likely to be condensed through binding with viral core proteins before encapsidation. Replicated viral genomes accumulate in the central region of the nucleus, which we termed virus-induced postreplication (ViPR) body. However, the molecular mechanism by which the nuclear structure is reorganized and its functional significance in virus production are currently not understood. In this study, we found that viral packaging protein IVa2, but not capsid proteins, accumulated in the ViPR body. In addition, nucleolar chromatin regulatory proteins, nucleophosmin 1 (NPM1), upstream binding factor, and nucleolin accumulated in the ViPR body in late-stage Ad infection. NPM1 depletion increased the nuclease-resistant viral genome and delayed the ViPR body formation. These results suggested that structural changes in the infected cell nucleus depend on the formation of viral chromatin by host chromatin regulatory proteins. Because NPM1 depletion decreases production of the infectious virion, we propose that host factor-mediated viral chromatin remodeling and concomitant ViPR body formation are prerequisites for efficient encapsidation of Ad chromatin.
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Affiliation(s)
- Michelle Jane Genoveso
- Ph.D. Program in Humanics, School of Integrative and Global Majors, University of Tsukuba, Japan.,Faculty of Medicine, University of Tsukuba, Japan
| | | | - Tetsuro Komatsu
- CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Université de Bordeaux, France.,Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Harald Wodrich
- CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Université de Bordeaux, France
| | | | - Mitsuru Okuwaki
- Faculty of Medicine, University of Tsukuba, Japan.,School of Pharmacy, Kitasato University, Tokyo, Japan
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8
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Porcine Adenovirus Type 3 E3 Encodes a Structural Protein Essential for Capsid Stability and Production of Infectious Progeny Virions. J Virol 2018; 92:JVI.00680-18. [PMID: 30068639 DOI: 10.1128/jvi.00680-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/16/2018] [Indexed: 11/20/2022] Open
Abstract
The adenovirus E3 region encodes proteins that are not essential for viral replication in vitro The porcine adenovirus type 3 (PAdV-3) E3 region encodes three proteins, including 13.7K. Here, we report that 13.7K is expressed as an early protein, which localizes to the nucleus of infected cells. The 13.7K protein is a structural protein, as it is incorporated in CsCl-purified virions. The 13.7K protein appears to be essential for PAdV-3 replication, as mutant PAV13.73A expressing a mutated 13.7K could be isolated only in VIDO AS2 cells expressing the 13.7K protein. Analysis of PAV13.73A suggested that even in the presence of reduced levels of some late viral proteins, there appeared to be no effect on virus assembly and production of mature virions. Further analysis of CsCl-purified PAV13.73A by transmission electron microscopy revealed the presence of disrupted/broken capsids, suggesting that inactivation of 13.7K protein expression may produce fragile capsids. Our results suggest that the PAdV-3 E3 region-encoded 13.7K protein is a capsid protein, which appears to be essential for the formation of stable capsids and production of infectious progeny virions.IMPORTANCE Although E3 region-encoded proteins are involved in the modulation of leukocyte functions (N. Arnberg, Proc Natl Acad Sci U S A 110:19976-19977, 2013) and inducing a lytic infection of lymphocytes (V. K. Murali, D. A. Ornelles, L. R. Gooding, H. T. Wilms, W. Huang, A. E. Tollefson, W. S. Wold, and C. Garnett-Benson, J Virol 88:903-912, 2014), none of the E3 proteins appear to be a component of virion capsid or required for replication of adenovirus. Here, we demonstrate that the 13.7K protein encoded by the E3 region of porcine adenovirus type 3 is a component of progeny virion capsids and appears to be essential for maintaining the integrity of virion capsid and production of infectious progeny virions. To our knowledge, this is the first report to suggest that an adenovirus E3-encoded protein is an essential structural protein.
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9
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Adenoviral E4 34K protein interacts with virus packaging components and may serve as the putative portal. Sci Rep 2017; 7:7582. [PMID: 28790440 PMCID: PMC5548797 DOI: 10.1038/s41598-017-07997-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 07/06/2017] [Indexed: 11/09/2022] Open
Abstract
Studies on dsDNA bacteriophages have revealed that a DNA packaging complex assembles at a special vertex called the 'portal vertex' and consists of a portal, a DNA packaging ATPase and other components. AdV protein IVa2 is presumed to function as a DNA packaging ATPase. However, a protein that functions as a portal is not yet identified in AdVs. To identify the AdV portal, we performed secondary structure analysis on a set of AdV proteins and compared them with the clip region of the portal proteins of bacteriophages phi29, SPP1 and T4. Our analysis revealed that the E4 34K protein of HAdV-C5 contains a region of strong similarity with the clip region of the known portal proteins. E4 34K was found to be present in empty as well as mature AdV particles. In addition, E4 34K co-immunoprecipitates and colocalizes with AdV packaging proteins. Immunogold electron microscopy demonstrated that E4 34K is located at a single site on the virus surface. Finally, tertiary structure prediction of E4 34K and its comparison with that of single subunits of Phi29, SPP1 and T4 portal proteins revealed remarkable similarity. In conclusion, our results suggest that E4 34K is the putative AdV portal protein.
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10
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Hassan AO, Vemula SV, Sharma A, Bangari DS, Mishra KK, Mittal SK. 155R is a novel structural protein of bovine adenovirus type 3, but it is not essential for virus replication. J Gen Virol 2017; 98:749-753. [PMID: 28086071 DOI: 10.1099/jgv.0.000707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bovine adenovirus (AdV) type 3 (BAdV-3) E1 region shares functional homology with E1 of human AdV type C5. Sequence analysis of the BAdV-3 E1 region revealed the presence of a novel 155R ORF that is not observed in other AdVs, on the lower strand antiparallel to a portion of the E1B region. The 155R gene products in BAdV-3-infected cells were identified by Northern blot, reverse transcriptase PCR followed by sequencing and Western blot analysis using the155R-specific antibody. 155R seems to be a late protein and is present in purified BAdV-3 particles. Replication kinetics of BAdV mutants with either one (BAdV/155R/mt1) or two (BAdV/155R/mt2) stop codons in the 155R ORF were comparable to those of BAdV-3, indicating that 155R is not essential for virus replication in cell culture. These results suggest that 155R-deleted BAdV-3 vectors could be generated in a cell line that fully complements BAdV-3 E1 functions.
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Affiliation(s)
- Ahmed O Hassan
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue Institute for Immunology, Inflammation and Infectious Diseases, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue University Center for Cancer Research, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
| | - Sai V Vemula
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue University Center for Cancer Research, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Present address: Merck Sharp and Dohme, West Point, PA, USA
| | - Anurag Sharma
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue University Center for Cancer Research, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Present address: Department of Pediatrics, Weill Cornell Medical College, New York, NY, USA
| | - Dinesh S Bangari
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue University Center for Cancer Research, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Present address: Department of Pathology, Sanofi Genzyme, 5 Mountain Road, Framingham, MA, USA
| | - Krishna K Mishra
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue University Center for Cancer Research, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Present address: Department of Biology, Ivy Tech Community College, Lafayette, IN, USA
| | - Suresh K Mittal
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue Institute for Immunology, Inflammation and Infectious Diseases, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA.,Purdue University Center for Cancer Research, College of Veterinary Medicine, Purdue University, West Lafayette, IN, USA
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11
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Condezo GN, San Martín C. Localization of adenovirus morphogenesis players, together with visualization of assembly intermediates and failed products, favor a model where assembly and packaging occur concurrently at the periphery of the replication center. PLoS Pathog 2017; 13:e1006320. [PMID: 28448571 PMCID: PMC5409498 DOI: 10.1371/journal.ppat.1006320] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/27/2017] [Indexed: 12/15/2022] Open
Abstract
Adenovirus (AdV) morphogenesis is a complex process, many aspects of which remain unclear. In particular, it is not settled where in the nucleus assembly and packaging occur, and whether these processes occur in a sequential or a concerted manner. Here we use immunofluorescence and immunoelectron microscopy (immunoEM) to trace packaging factors and structural proteins at late times post infection by either wildtype virus or a delayed packaging mutant. We show that representatives of all assembly factors are present in the previously recognized peripheral replicative zone, which therefore is the AdV assembly factory. Assembly intermediates and abortive products observed in this region favor a concurrent assembly and packaging model comprising two pathways, one for capsid proteins and another one for core components. Only when both pathways are coupled by correct interaction between packaging proteins and the genome is the viral particle produced. Decoupling generates accumulation of empty capsids and unpackaged cores.
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Affiliation(s)
- Gabriela N. Condezo
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
| | - Carmen San Martín
- Department of Macromolecular Structures, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
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12
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Ahi YS, Mittal SK. Components of Adenovirus Genome Packaging. Front Microbiol 2016; 7:1503. [PMID: 27721809 PMCID: PMC5033970 DOI: 10.3389/fmicb.2016.01503] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 09/08/2016] [Indexed: 12/29/2022] Open
Abstract
Adenoviruses (AdVs) are icosahedral viruses with double-stranded DNA (dsDNA) genomes. Genome packaging in AdV is thought to be similar to that seen in dsDNA containing icosahedral bacteriophages and herpesviruses. Specific recognition of the AdV genome is mediated by a packaging domain located close to the left end of the viral genome and is mediated by the viral packaging machinery. Our understanding of the role of various components of the viral packaging machinery in AdV genome packaging has greatly advanced in recent years. Characterization of empty capsids assembled in the absence of one or more components involved in packaging, identification of the unique vertex, and demonstration of the role of IVa2, the putative packaging ATPase, in genome packaging have provided compelling evidence that AdVs follow a sequential assembly pathway. This review provides a detailed discussion on the functions of the various viral and cellular factors involved in AdV genome packaging. We conclude by briefly discussing the roles of the empty capsids, assembly intermediates, scaffolding proteins, portal vertex and DNA encapsidating enzymes in AdV assembly and packaging.
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Affiliation(s)
- Yadvinder S Ahi
- Department of Comparative Pathobiology, Purdue UniversityWest Lafayette, IN, USA; Purdue University Center for Cancer Research, Purdue UniversityWest Lafayette, IN, USA
| | - Suresh K Mittal
- Department of Comparative Pathobiology, Purdue UniversityWest Lafayette, IN, USA; Purdue University Center for Cancer Research, Purdue UniversityWest Lafayette, IN, USA; Purdue Institute for Immunology, Inflammation and Infectious Diseases, Purdue UniversityWest Lafayette, IN, USA
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