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Kulanayake S, Singh B, Dar F, Tikoo SK. Role of Protein VII in the Production of Infectious Bovine Adenovirus-3 Virion. Viruses 2024; 16:1323. [PMID: 39205297 PMCID: PMC11359501 DOI: 10.3390/v16081323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2024] [Revised: 08/10/2024] [Accepted: 08/13/2024] [Indexed: 09/04/2024] Open
Abstract
Bovine adenovirus (BAdV)-3 genome encodes a 26 kDa core protein designated as protein VII, which localizes to the nucleus/nucleolus. The requirement of a protein VII-complementing cell line for the replication of VII-deleted BAdV-3 suggests that protein VII is required for the production of infectious progeny virions. An analysis of the BAV.VIId+ virus (only phenotypically positive for protein VII) detected no noticeable differences in the expression and incorporation of viral proteins in the virions. Moreover, protein VII does not appear to be essential for the formation of mature BAV.VIId+. However, protein VII appeared to be required for the efficient assembly of mature BAV.VIId- virions. An analysis of the BAV.VIId- virus (genotypically and phenotypically negative for protein VII) in non-complementing cells detected the inefficient release of virions from endosomes, which affected the expression of viral proteins or DNA replication. Moreover, the absence of protein VII altered the proteolytic cleavage of protein VI of BAV.VIId-. Our results suggest that BAdV-3 protein VII appears to be required for efficient production of mature virions. Moreover, the absence of protein VII produces non-infectious BAdV-3 by altering the release of BAdV-3 from endosomes/vesicles.
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Affiliation(s)
- Shermila Kulanayake
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; (S.K.); (F.D.)
- Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
| | - Barinder Singh
- Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
| | - Faryal Dar
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; (S.K.); (F.D.)
- Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
| | - Suresh K. Tikoo
- Vaccinology & Immunotherapeutics Program, School of Public Health, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada; (S.K.); (F.D.)
- Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada;
- Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
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2
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Athukorala A, Helbig KJ, McSharry BP, Forwood JK, Sarker S. An optimised protocol for the expression and purification of adenovirus core protein VII. J Virol Methods 2024; 326:114907. [PMID: 38432358 DOI: 10.1016/j.jviromet.2024.114907] [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: 11/05/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/05/2024]
Abstract
Adenovirus protein VII (pVII) is a highly basic core protein, bearing resemblance to mammalian histones. Despite its diverse functions, a comprehensive understanding of its structural intricacies and the mechanisms underlying its functions remain elusive, primarily due to the complexity of producing a good amount of soluble pVII. This study aimed to optimise the expression and purification of recombinant pVII from four different adenoviruses with a simple vector construct. This study successfully determined the optimal conditions for efficiently purifying pVII across four adenovirus species, revealing the differential preference for bacterial expression systems. The One Shot BL21 Star (DE3) proved favourable over Rosetta 2 (DE3) pLysS with consistent levels of expression between IPTG-induced and auto-induction. We demonstrated that combining chemical and mechanical cell lysis is possible and highly effective. Other noteworthy benefits were observed in using RNase during sample processing. The addition of RNase has significantly improved the quality and quantity of the purified protein as confirmed by chromatographic and western blot analyses. These findings established a solid groundwork for pVII purification methodologies and carry the significant potential to assist in unveiling the core structure of pVII, its arrangement within the core, DNA condensation intricacies, and potential pathways for nuclear transport.
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Affiliation(s)
- Ajani Athukorala
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Karla J Helbig
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Brian P McSharry
- School of Dentistry and Medical Sciences Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Jade K Forwood
- School of Dentistry and Medical Sciences Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia
| | - Subir Sarker
- Biomedical Sciences and Molecular Biology, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia.
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3
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Athukorala A, Donnelly CM, Pavan S, Nematollahzadeh S, Djossou VA, Nath B, Helbig KJ, Di Iorio E, McSharry BP, Alvisi G, Forwood JK, Sarker S. Structural and functional characterization of siadenovirus core protein VII nuclear localization demonstrates the existence of multiple nuclear transport pathways. J Gen Virol 2024; 105. [PMID: 38261399 DOI: 10.1099/jgv.0.001928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024] Open
Abstract
Adenovirus protein VII (pVII) plays a crucial role in the nuclear localization of genomic DNA following viral infection and contains nuclear localization signal (NLS) sequences for the importin (IMP)-mediated nuclear import pathway. However, functional analysis of pVII in adenoviruses to date has failed to fully determine the underlying mechanisms responsible for nuclear import of pVII. Therefore, in the present study, we extended our analysis by examining the nuclear trafficking of adenovirus pVII from a non-human species, psittacine siadenovirus F (PsSiAdV). We identified a putative classical (c)NLS at pVII residues 120-128 (120PGGFKRRRL128). Fluorescence polarization and electrophoretic mobility shift assays demonstrated direct, high-affinity interaction with both IMPα2 and IMPα3 but not IMPβ. Structural analysis of the pVII-NLS/IMPα2 complex confirmed a classical interaction, with the major binding site of IMPα occupied by K124 of pVII-NLS. Quantitative confocal laser scanning microscopy showed that PsSiAdV pVII-NLS can confer IMPα/β-dependent nuclear localization to GFP. PsSiAdV pVII also localized in the nucleus when expressed in the absence of other viral proteins. Importantly, in contrast to what has been reported for HAdV pVII, PsSiAdV pVII does not localize to the nucleolus. In addition, our study demonstrated that inhibition of the IMPα/β nuclear import pathway did not prevent PsSiAdV pVII nuclear targeting, indicating the existence of alternative pathways for nuclear localization, similar to what has been previously shown for human adenovirus pVII. Further examination of other potential NLS signals, characterization of alternative nuclear import pathways, and investigation of pVII nuclear targeting across different adenovirus species is recommended to fully elucidate the role of varying nuclear import pathways in the nuclear localization of pVII.
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Affiliation(s)
- Ajani Athukorala
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Camilla M Donnelly
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Silvia Pavan
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | - Sepehr Nematollahzadeh
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | | | - Babu Nath
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Karla J Helbig
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Enzo Di Iorio
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | - Brian P McSharry
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Gualtiero Alvisi
- Department of Molecular Medicine, University of Padua, Via Gabelli 63, 35121 Padua, Italy
| | - Jade K Forwood
- School of Dentistry and Medical Sciences, Biomedical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Subir Sarker
- Department of Microbiology, Anatomy, Physiology, and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
- Biomedical Sciences & Molecular Biology, College of Public Health Medical, and Veterinary Sciences, James Cook University, Townsville, QLD 4811, Australia
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Lagadec F, Carlon-Andres I, Ragues J, Port S, Wodrich H, Kehlenbach RH. CRM1 Promotes Capsid Disassembly and Nuclear Envelope Translocation of Adenovirus Independently of Its Export Function. J Virol 2022; 96:e0127321. [PMID: 34757845 PMCID: PMC8826800 DOI: 10.1128/jvi.01273-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 11/01/2021] [Indexed: 11/20/2022] Open
Abstract
After receptor-mediated endocytosis and endosomal escape, adenoviral capsids can travel via microtubule organizing centers to the nuclear envelope. Upon capsid disassembly, viral genome import into nuclei of interphase cells then occurs through nuclear pore complexes, involving the nucleoporins Nup214 and Nup358. Import also requires the activity of the classic nuclear export receptor CRM1, as it is blocked by the selective inhibitor leptomycin B. We have now used artificially enucleated as well as mitotic cells to analyze the role of an intact nucleus in different steps of the viral life cycle. In enucleated U2OS cells, viral capsids traveled to the microtubule organizing center, whereas their removal from this complex was blocked, suggesting that this step required nuclear factors. In mitotic cells, on the other hand, CRM1 promoted capsid disassembly and genome release, suggesting a role of this protein that does not require intact nuclear envelopes or nuclear pore complexes and is distinct from its function as a nuclear export receptor. Similar to enucleation, inhibition of CRM1 by leptomycin B also leads to an arrest of adenoviral capsids at the microtubule organizing center. In a small-scale screen using leptomycin B-resistant versions of CRM1, we identified a mutant, CRM1 W142A P143A, that is compromised with respect to adenoviral capsid disassembly in both interphase and mitotic cells. Strikingly, this mutant is capable of exporting cargo proteins out of the nucleus of living cells or digitonin-permeabilized cells, pointing to a role of the mutated region that is not directly linked to nuclear export. IMPORTANCE A role of nucleoporins and of soluble transport factors in adenoviral genome import into the nucleus of infected cells in interphase has previously been established. The nuclear export receptor CRM1 promotes genome import, but its precise function is not known. Using enucleated and mitotic cells, we showed that CRM1 does not simply function by exporting a crucial factor out of the nucleus that would then trigger capsid disassembly and genome import. Instead, CRM1 has an export-independent role, a notion that is also supported by a mutant, CRM1 W142A P143A, which is export competent but deficient in viral capsid disassembly, in both interphase and mitotic cells.
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Affiliation(s)
- Floriane Lagadec
- Department of Molecular Biology, Faculty of Medicine, Göttingen Center of Biosciences (GZMB), Georg-August-University Göttingen, Göttingen, Germany
- CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Université de Bordeaux, Bordeaux, France
| | - Irene Carlon-Andres
- CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Université de Bordeaux, Bordeaux, France
| | - Jessica Ragues
- CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Université de Bordeaux, Bordeaux, France
| | - Sarah Port
- Department of Molecular Biology, Faculty of Medicine, Göttingen Center of Biosciences (GZMB), Georg-August-University Göttingen, Göttingen, Germany
| | - Harald Wodrich
- CNRS UMR 5234, Fundamental Microbiology and Pathogenicity, Université de Bordeaux, Bordeaux, France
| | - Ralph H. Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Göttingen Center of Biosciences (GZMB), Georg-August-University Göttingen, Göttingen, Germany
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5
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Lynch KL, Dillon MR, Bat-Erdene M, Lewis HC, Kaai RJ, Arnold EA, Avgousti DC. A viral histone-like protein exploits antagonism between linker histones and HMGB proteins to obstruct the cell cycle. Curr Biol 2021; 31:5227-5237.e7. [PMID: 34666003 DOI: 10.1016/j.cub.2021.09.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 06/30/2021] [Accepted: 09/17/2021] [Indexed: 11/17/2022]
Abstract
Virus infection necessarily requires redirecting cellular resources toward viral progeny production. Adenovirus encodes the histone-like protein VII, which causes catastrophic global reorganization of host chromatin to promote virus infection. Protein VII recruits the family of high mobility group box (HMGB) proteins to chromatin along with the histone chaperone SET. As a consequence of this recruitment, we find that protein VII causes chromatin depletion of several linker histone H1 isoforms. The relationship between linker histone H1 and the functionally opposite HMGB proteins is critical for higher-order chromatin structure. However, the physiological consequences of perturbing this relationship are largely unknown. Here, we employ complementary systems in Saccharomyces cerevisiae and human cells to demonstrate that adenovirus protein VII disrupts the H1-HMGB balance to obstruct the cell cycle. We find that protein VII causes an accumulation of G2/M cells both in yeast and human systems, underscoring the high conservation of this chromatin vulnerability. In contrast, adenovirus E1A and E1B proteins are well established to override cell cycle regulation and promote transformation of human cells. Strikingly, we find that protein VII obstructs the cell cycle, even in the presence of E1A and E1B. We further show that, in a protein-VII-deleted infection, several cell cycle markers are regulated differently compared to wild-type infection, supporting our model that protein VII plays an integral role in hijacking cell cycle regulation during infection. Together, our results demonstrate that protein VII targets H1-HMGB1 antagonism to obstruct cell cycle progression, revealing an unexpected chromatin vulnerability exploited for viral benefit.
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Affiliation(s)
- Kelsey L Lynch
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Melanie R Dillon
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Mongoljin Bat-Erdene
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Hannah C Lewis
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA; Molecular & Cellular Biology in Seattle, Graduate Program, University of Washington and Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Robin J Kaai
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA; Molecular & Cellular Biology in Seattle, Graduate Program, University of Washington and Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
| | - Edward A Arnold
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA; Microbiology Graduate Program, University of Washington, 1705 NE Pacific Street, Box 357735, Seattle, WA 98195, USA
| | - Daphne C Avgousti
- Human Biology Division, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA; Molecular & Cellular Biology in Seattle, Graduate Program, University of Washington and Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA; Microbiology Graduate Program, University of Washington, 1705 NE Pacific Street, Box 357735, Seattle, WA 98195, USA.
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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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Double-edged role of PML nuclear bodies during human adenovirus infection. Virus Res 2020; 295:198280. [PMID: 33370557 DOI: 10.1016/j.virusres.2020.198280] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/21/2020] [Accepted: 12/23/2020] [Indexed: 01/31/2023]
Abstract
PML nuclear bodies are matrix-bound nuclear structures with a variety of functions in human cells. These nuclear domains are interferon regulated and play an essential role during virus infections involving accumulation of SUMO-dependent host and viral factors. PML-NBs are targeted and subsequently manipulated by adenoviral regulatory proteins, illustrating their crucial role during productive infection and virus-mediated oncogenic transformation. PML-NBs have a longstanding antiviral reputation; however, the genomes of Human Adenoviruses and initial sites of viral transcription/replication are found juxtaposed to these domains, resulting in a double-edged capacity of these nuclear multiprotein/multifunctional complexes. This enigma provides evidence that Human Adenoviruses selectively counteract antiviral responses, and simultaneously benefit from or even depend on proviral PML-NB associated components by active recruitment to PML track-like structures, that are induced during infection. Thereby, a positive microenvironment for adenoviral transcription and replication is created at these nuclear subdomains. Based on the available data, this review aims to provide a detailed overview of the current knowledge of Human Adenovirus crosstalk with nuclear PML body compartments as sites of SUMOylation processes in the host cells, evaluating the currently known principles and molecular mechanisms.
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8
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Charman M, Herrmann C, Weitzman MD. Viral and cellular interactions during adenovirus DNA replication. FEBS Lett 2019; 593:3531-3550. [PMID: 31764999 DOI: 10.1002/1873-3468.13695] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/30/2022]
Abstract
Adenoviruses represent ubiquitous and clinically significant human pathogens, gene-delivery vectors, and oncolytic agents. The study of adenovirus-infected cells has long been used as an excellent model to investigate fundamental aspects of both DNA virus infection and cellular biology. While many key details supporting a well-established model of adenovirus replication have been elucidated over a period spanning several decades, more recent findings suggest that we have only started to appreciate the complex interplay between viral genome replication and cellular processes. Here, we present a concise overview of adenovirus DNA replication, including the biochemical process of replication, the spatial organization of replication within the host cell nucleus, and insights into the complex plethora of virus-host interactions that influence viral genome replication. Finally, we identify emerging areas of research relating to the replication of adenovirus genomes.
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Affiliation(s)
- Matthew Charman
- Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Christin Herrmann
- Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Matthew D Weitzman
- Division of Protective Immunity and Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
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9
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Pied N, Wodrich H. Imaging the adenovirus infection cycle. FEBS Lett 2019; 593:3419-3448. [PMID: 31758703 DOI: 10.1002/1873-3468.13690] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/18/2019] [Accepted: 11/20/2019] [Indexed: 12/11/2022]
Abstract
Incoming adenoviruses seize control of cytosolic transport mechanisms to relocate their genome from the cell periphery to specialized sites in the nucleoplasm. The nucleus is the site for viral gene expression, genome replication, and the production of progeny for the next round of infection. By taking control of the cell, adenoviruses also suppress cell-autonomous immunity responses. To succeed in their production cycle, adenoviruses rely on well-coordinated steps, facilitated by interactions between viral proteins and cellular factors. Interactions between virus and host can impose remarkable morphological changes in the infected cell. Imaging adenoviruses has tremendously influenced how we delineate individual steps in the viral life cycle, because it allowed the development of specific optical markers to label these morphological changes in space and time. As technology advances, innovative imaging techniques and novel tools for specimen labeling keep uncovering previously unseen facets of adenovirus biology emphasizing why imaging adenoviruses is as attractive today as it was in the past. This review will summarize past achievements and present developments in adenovirus imaging centered on fluorescence microscopy approaches.
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Affiliation(s)
- Noémie Pied
- CNRS UMR 5234, Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, France
| | - Harald Wodrich
- CNRS UMR 5234, Microbiologie Fondamentale et Pathogénicité, Université de Bordeaux, France
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10
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Lobaina Y, Perera Y. Implication of B23/NPM1 in Viral Infections, Potential Uses of B23/NPM1 Inhibitors as Antiviral Therapy. Infect Disord Drug Targets 2019; 19:2-16. [PMID: 29589547 DOI: 10.2174/1871526518666180327124412] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/08/2018] [Accepted: 02/12/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND B23/nucleophosmin (B23/NPM1) is an abundant multifunctional protein mainly located in the nucleolus but constantly shuttling between the nucleus and cytosol. As a consequence of its constitutive expression, intracellular dynamics and binding capacities, B23/NPM1 interacts with multiple cellular factors in different cellular compartments, but also with viral proteins from both DNA and RNA viruses. B23/NPM1 influences overall viral replication of viruses like HIV, HBV, HCV, HDV and HPV by playing functional roles in different stages of viral replication including nuclear import, viral genome transcription and assembly, as well as final particle formation. Of note, some virus modify the subcellular localization, stability and/or increases B23/NPM1 expression levels on target cells, probably to foster B23/NPM1 functions in their own replicative cycle. RESULTS This review summarizes current knowledge concerning the interaction of B23/NPM1 with several viral proteins during relevant human infections. The opportunities and challenges of targeting this well-conserved host protein as a potentially new broad antiviral treatment are discussed in detail. Importantly, although initially conceived to treat cancer, a handful of B23/NPM1 inhibitors are currently available to test on viral infection models. CONCLUSION As B23/NPM1 partakes in key steps of viral replication and some viral infections remain as unsolved medical needs, an appealing idea may be the expedite evaluation of B23/NPM1 inhibitors in viral infections. Furthermore, worth to be addressed is if the up-regulation of B23/NPM1 protein levels that follows persistent viral infections may be instrumental to the malignant transformation induced by virus like HBV and HCV.
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Affiliation(s)
- Yadira Lobaina
- Therapeutic Hepatitis B Vaccine Group, Vaccine Division, Biomedical Research Direction, Center for Genetic Engineering and Biotechnology, Havana, CP 10600, Cuba
| | - Yasser Perera
- Molecular Oncology Group, Pharmaceuticals Division, Biomedical Research Direction, Center for Genetic Engineering and Biotechnology, Havana, CP 10600, Cuba
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11
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Tarakhovsky A, Prinjha RK. Drawing on disorder: How viruses use histone mimicry to their advantage. J Exp Med 2018; 215:1777-1787. [PMID: 29934321 PMCID: PMC6028506 DOI: 10.1084/jem.20180099] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/24/2018] [Accepted: 06/07/2018] [Indexed: 12/16/2022] Open
Abstract
Humans carry trillions of viruses that thrive because of their ability to exploit the host. In this exploitation, viruses promote their own replication by suppressing the host antiviral response and by inducing changes in host biosynthetic processes, often with extremely small genomes of their own. In the review, we discuss the phenomenon of histone mimicry by viral proteins and how this mimicry allows the virus to dial in to the cell's transcriptional processes and establish a cell state that promotes infection. We suggest that histone mimicry is part of a broader viral strategy to use intrinsic protein disorder as a means to overcome the size limitations of its own genome and to maximize its impact on host protein networks. In particular, we discuss how intrinsic protein disorder may enable viral proteins to interfere with phase-separated host protein condensates, including those that contribute to chromatin-mediated control of gene expression.
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Affiliation(s)
- Alexander Tarakhovsky
- Laboratory of the Immune Cell Epigenetics and Signaling, The Rockefeller University, New York, NY
| | - Rab K Prinjha
- Epigenetics DPU, Oncology and Immuno-inflammation TA Units, GlaxoSmithKline Medicines Research Centre, Stevenage, England, UK
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12
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King CR, Tessier TM, Mymryk JS. Color Me Infected: Painting Cellular Chromatin with a Viral Histone Mimic. Trends Microbiol 2016; 24:774-776. [PMID: 27592243 DOI: 10.1016/j.tim.2016.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/16/2016] [Indexed: 10/21/2022]
Abstract
Viruses manipulate cellular chromatin to create a favourable milieu for infection. In several cases, virally-encoded proteins structurally mimic cellular histones to molecularly rewire the host cell. A recent study identified a novel mechanism whereby adenovirus protein VII, a viral histone, binds and manipulates host cell chromatin to suppress inflammatory signalling.
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Affiliation(s)
- Cason R King
- Department of Microbiology & Immunology, University of Western Ontario, London, Ontario, Canada
| | - Tanner M Tessier
- Department of Microbiology & Immunology, University of Western Ontario, London, Ontario, Canada
| | - Joe S Mymryk
- Department of Microbiology & Immunology, University of Western Ontario, London, Ontario, Canada; Departments of Oncology and Otolaryngology, University of Western Ontario, London, Ontario, Canada; London Regional Cancer Program and Lawson Health Research Institute, London, Ontario, Canada.
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13
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Schreiner S, Kinkley S, Bürck C, Mund A, Wimmer P, Schubert T, Groitl P, Will H, Dobner T. SPOC1-mediated antiviral host cell response is antagonized early in human adenovirus type 5 infection. PLoS Pathog 2013; 9:e1003775. [PMID: 24278021 PMCID: PMC3836738 DOI: 10.1371/journal.ppat.1003775] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Accepted: 10/04/2013] [Indexed: 01/22/2023] Open
Abstract
Little is known about immediate phases after viral infection and how an incoming viral genome complex counteracts host cell defenses, before the start of viral gene expression. Adenovirus (Ad) serves as an ideal model, since entry and onset of gene expression are rapid and highly efficient, and mechanisms used 24–48 hours post infection to counteract host antiviral and DNA repair factors (e.g. p53, Mre11, Daxx) are well studied. Here, we identify an even earlier host cell target for Ad, the chromatin-associated factor and epigenetic reader, SPOC1, recently found recruited to double strand breaks, and playing a role in DNA damage response. SPOC1 co-localized with viral replication centers in the host cell nucleus, interacted with Ad DNA, and repressed viral gene expression at the transcriptional level. We discovered that this SPOC1-mediated restriction imposed upon Ad growth is relieved by its functional association with the Ad major core protein pVII that enters with the viral genome, followed by E1B-55K/E4orf6-dependent proteasomal degradation of SPOC1. Mimicking removal of SPOC1 in the cell, knock down of this cellular restriction factor using RNAi techniques resulted in significantly increased Ad replication, including enhanced viral gene expression. However, depletion of SPOC1 also reduced the efficiency of E1B-55K transcriptional repression of cellular promoters, with possible implications for viral transformation. Intriguingly, not exclusive to Ad infection, other human pathogenic viruses (HSV-1, HSV-2, HIV-1, and HCV) also depleted SPOC1 in infected cells. Our findings provide a general model for how pathogenic human viruses antagonize intrinsic SPOC1-mediated antiviral responses in their host cells. A better understanding of viral entry and early restrictive functions in host cells should provide new perspectives for developing antiviral agents and therapies. Conversely, for Ad vectors used in gene therapy, counteracting mechanisms eradicating incoming viral DNA would increase Ad vector efficacy and safety for the patient. Viruses have acquired functions that target and modulate host cell signaling and diverse regulatory cascades, leading to efficient viral propagation. During the course of productive infection, Ad gene products manipulate destruction pathways to prevent viral clearance or cell death prior to viral genome amplification and release of progeny. Recently, we reported that chromatin formation and cellular SWI/SNF chromatin remodeling processes play a key role in Ad transcriptional regulation. Here, we observe for the first time that SPOC1, identified as a regulator of DNA damage response and chromatin structure, plays an essential role in restricting Ad gene expression and progeny production. This host cell antiviral mechanism is efficiently counteracted by tight association with the major core protein pVII bound to the incoming viral genome. Subsequently, SPOC1 undergoes proteasomal degradation via the Ad E1B-55K/E4orf6-dependent, Cullin-based E3 ubiquitin ligase complex. We also show that other viruses from RNA and DNA families also induce efficient degradation of SPOC1. These analyses of evasion strategies acquired by viruses and other human pathogens should provide important insights into factors manipulating the epigenetic environment to potentially inactivate, or amplify host cell immune responses, since detailed molecular mechanisms and the full repertoire of cellular targets still remain elusive.
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Affiliation(s)
- Sabrina Schreiner
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Sarah Kinkley
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Carolin Bürck
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Andreas Mund
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Peter Wimmer
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Tobias Schubert
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Peter Groitl
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Hans Will
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Thomas Dobner
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
- * E-mail:
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14
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Inturi R, Thaduri S, Punga T. Adenovirus precursor pVII protein stability is regulated by its propeptide sequence. PLoS One 2013; 8:e80617. [PMID: 24260437 PMCID: PMC3829898 DOI: 10.1371/journal.pone.0080617] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/04/2013] [Indexed: 11/18/2022] Open
Abstract
Adenovirus encodes for the pVII protein, which interacts and modulates virus DNA structure in the infected cells. The pVII protein is synthesized as the precursor protein and undergoes proteolytic processing by viral proteinase Avp, leading to release of a propeptide sequence and accumulation of the mature VII protein. Here we elucidate the molecular functions of the propeptide sequence present in the precursor pVII protein. The results show that the propeptide is the destabilizing element targeting the precursor pVII protein for proteasomal degradation. Our data further indicate that the propeptide sequence and the lysine residues K26 and K27 regulate the precursor pVII protein stability in a co-dependent manner. We also provide evidence that the Cullin-3 E3 ubiquitin ligase complex alters the precursor pVII protein stability by association with the propeptide sequence. In addition, we show that inactivation of the Cullin-3 protein activity reduces adenovirus E1A gene expression during early phase of virus infection. Collectively, our results indicate a novel function of the adenovirus propeptide sequence and involvement of Cullin-3 in adenovirus gene expression.
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Affiliation(s)
- Raviteja Inturi
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Srinivas Thaduri
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Tanel Punga
- Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- * E-mail:
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15
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Hsu CYM, Uludağ H. Nucleic-acid based gene therapeutics: delivery challenges and modular design of nonviral gene carriers and expression cassettes to overcome intracellular barriers for sustained targeted expression. J Drug Target 2012; 20:301-28. [PMID: 22303844 DOI: 10.3109/1061186x.2012.655247] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The delivery of nucleic acid molecules into cells to alter physiological functions at the genetic level is a powerful approach to treat a wide range of inherited and acquired disorders. Biocompatible materials such as cationic polymers, lipids, and peptides are being explored as safer alternatives to viral gene carriers. However, the comparatively low efficiency of nonviral carriers currently hampers their translation into clinical settings. Controlling the size and stability of carrier/nucleic acid complexes is one of the primary hurdles as the physicochemical properties of the complexes can define the uptake pathways, which dictate intracellular routing, endosomal processing, and nucleocytoplasmic transport. In addition to nuclear import, subnuclear trafficking, posttranscriptional events, and immune responses can further limit transfection efficiency. Chemical moieties, reactive linkers or signal peptide have been conjugated to carriers to prevent aggregation, induce membrane destabilization and localize to subcellular compartments. Genetic elements can be inserted into the expression cassette to facilitate nuclear targeting, delimit expression to targeted tissue, and modulate transgene expression. The modular option afforded by both gene carriers and expression cassettes provides a two-tier multicomponent delivery system that can be optimized for targeted gene delivery in a variety of settings.
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Affiliation(s)
- Charlie Yu Ming Hsu
- Department of Biomedical Engineering, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Cananda
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16
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Affiliation(s)
- Mark O. J. Olson
- Dept. Biochemistry, University of Mississippi Medical Center, North State St. 2500, Jackson, 39216 Mississippi USA
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17
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Scott MS, Troshin PV, Barton GJ. NoD: a Nucleolar localization sequence detector for eukaryotic and viral proteins. BMC Bioinformatics 2011; 12:317. [PMID: 21812952 PMCID: PMC3166288 DOI: 10.1186/1471-2105-12-317] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/03/2011] [Indexed: 12/15/2022] Open
Abstract
Background Nucleolar localization sequences (NoLSs) are short targeting sequences responsible for the localization of proteins to the nucleolus. Given the large number of proteins experimentally detected in the nucleolus and the central role of this subnuclear compartment in the cell, NoLSs are likely to be important regulatory elements controlling cellular traffic. Although many proteins have been reported to contain NoLSs, the systematic characterization of this group of targeting motifs has only recently been carried out. Results Here, we describe NoD, a web server and a command line program that predicts the presence of NoLSs in proteins. Using the web server, users can submit protein sequences through the NoD input form and are provided with a graphical output of the NoLS score as a function of protein position. While the web server is most convenient for making prediction for just a few proteins, the command line version of NoD can return predictions for complete proteomes. NoD is based on our recently described human-trained artificial neural network predictor. Through stringent independent testing of the predictor using available experimentally validated NoLS-containing eukaryotic and viral proteins, the NoD sensitivity and positive predictive value were estimated to be 71% and 79% respectively. Conclusions NoD is the first tool to provide predictions of nucleolar localization sequences in diverse eukaryotes and viruses. NoD can be run interactively online at http://www.compbio.dundee.ac.uk/nod or downloaded to use locally.
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Affiliation(s)
- Michelle S Scott
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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18
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Abstract
Recent advances in proteomics have been combined with traditional methods for isolation of nucleoli from mammalian and plant cells. This approach has confirmed the growing body of data showing a wide role for the nucleolus in eukaryotic cell biology beyond ribosome generation into many areas of cell function from regulation of the cell cycle, modulation of the cell stress response to innate immune responses. This has been reflected in the growing body of evidence that viruses specifically target the nucleolus by sequestering cellular nucleolar proteins or by targeting viral proteins to the nucleolus in order to maximise viral replication. This review covers those key areas and looks at the latest approaches using high‐throughput quantitative proteomics of the nucleolus in virus infected cells to gain an insight into the role of this fascinating compartment in viral infection.
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Affiliation(s)
- Julian A Hiscox
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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19
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Lamarre B, Ryadnov MG. Self-assembling viral mimetics: one long journey with short steps. Macromol Biosci 2010; 11:503-13. [PMID: 21165940 DOI: 10.1002/mabi.201000330] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Indexed: 12/14/2022]
Abstract
Recently, the Foresight Institute has pronounced six economic challenges that can be addressed through the progress of nanotechnology. One of these is the health and longevity of human life. Amongst applications anticipated to provide a solution to this challenge, gene therapy appears to be particularly promising. In theory, many diseases that result from genetic disorders can be cured by correcting defective genes. In practice, finding efficient and safe delivery vectors remains the stumbling point on the path of genetic therapies to the clinic. Viruses, otherwise the most efficient transfectors, pose safety concerns over immune reactions, whereas synthetic gene packages greatly lack the structural integrity of viruses. An ideal vector is therefore seen as a compromise between the two: a nanoscale device, which would mimic a virus and act as a virus, but would do this at the designer's whim. A strategy to achieve this is offered by the virus architecture itself, the principles of which are translated into the function via exquisitely reproducible self-assembly mechanisms. Thus, to mimic a virus is to mimic the way it is built, i.e., self-assembly. With just a few attempts made so far, the journey to an artificial virus has had a short lifetime, but the promise it holds is not expected to reduce any time soon.
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Affiliation(s)
- Baptiste Lamarre
- National Physical Laboratory, Teddington, Middlesex, TW110LW, UK
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20
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Cohen S, Au S, Panté N. How viruses access the nucleus. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1634-45. [PMID: 21167871 DOI: 10.1016/j.bbamcr.2010.12.009] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 11/24/2010] [Accepted: 12/08/2010] [Indexed: 10/25/2022]
Abstract
Many viruses depend on nuclear proteins for replication. Therefore, their viral genome must enter the nucleus of the host cell. In this review we briefly summarize the principles of nucleocytoplasmic transport, and then describe the diverse strategies used by viruses to deliver their genomes into the host nucleus. Some of the emerging mechanisms include: (1) nuclear entry during mitosis, when the nuclear envelope is disassembled, (2) viral genome release in the cytoplasm followed by entry of the genome through the nuclear pore complex (NPC), (3) capsid docking at the cytoplasmic side of the NPC, followed by genome release, (4) nuclear entry of intact capsids through the NPC, followed by genome release, and (5) nuclear entry via virus-induced disruption of the nuclear envelope. Which mechanism a particular virus uses depends on the size and structure of the virus, as well as the cellular cues used by the virus to trigger capsid disassembly and genome release. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Sarah Cohen
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada
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21
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Emmott E, Wise H, Loucaides EM, Matthews DA, Digard P, Hiscox JA. Quantitative proteomics using SILAC coupled to LC-MS/MS reveals changes in the nucleolar proteome in influenza A virus-infected cells. J Proteome Res 2010; 9:5335-45. [PMID: 20701360 DOI: 10.1021/pr100593g] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Influenza A virus (IAV) is a major human pathogen whose genotypic diversity results in unpredictable pandemics and epidemics. Interaction with the cell nucleus is essential to IAV infection, allowing recruitment of cellular components to facilitate virus replication. Viral proteins are also targeted to the nucleolus, a subnuclear structure involved in ribosomal biogenesis, RNA maturation, stress response, and control of cell growth, but the functional consequences of this are unclear. We took an unbiased approach to studying IAV-nucleolar interactions by using stable isotope labeling with amino acids in cell culture (SILAC) in conjunction with LC-MS/MS to quantify changes in the nucleolar proteome following infection with A/PR/8/34 (H1N1) and A/Udorn/72 (H3N2) strains of the virus. Only a minority of nucleolar proteins showed significant changes in abundance after infection; these alterations were mostly different between the two strains but could be validated by confocal microscopy of infected cells. Many of the affected proteins comprised functional groupings, including components of ribonuclease P, RNA polymerase I, the MLL1 histone methyltransferase complex, as well as nuclear paraspeckles and the RNA editing apparatus. This, as well as comparison with other viruses that cause changes in the nucleolar proteome, suggests that IAV targets specific nucleolar pathways.
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Affiliation(s)
- Edward Emmott
- Institute of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, United Kingdom
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22
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Chailertvanitkul VA, Pouton CW. Adenovirus: a blueprint for non-viral gene delivery. Curr Opin Biotechnol 2010; 21:627-32. [PMID: 20638266 DOI: 10.1016/j.copbio.2010.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Revised: 06/22/2010] [Accepted: 06/23/2010] [Indexed: 02/02/2023]
Abstract
Although adenoviral vectors may not find a direct clinical role in gene therapy, an understanding of the mechanisms of DNA delivery that adenoviruses use is of vital importance to the design of next-generation non-viral gene delivery systems. Adenoviruses overcome a series of biological barriers, including endosomal escape, intracellular trafficking, capsid dissociation, and nuclear import of DNA, to deliver their genome to the host cell nucleus. The understanding of these processes at the molecular level is progressing and is set to inform the design of synthetic gene delivery systems.
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Affiliation(s)
- V Ann Chailertvanitkul
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), Melbourne, Australia
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23
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Bremner KH, Scherer J, Yi J, Vershinin M, Gross SP, Vallee RB. Adenovirus transport via direct interaction of cytoplasmic dynein with the viral capsid hexon subunit. Cell Host Microbe 2010; 6:523-35. [PMID: 20006841 DOI: 10.1016/j.chom.2009.11.006] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Revised: 09/18/2009] [Accepted: 10/19/2009] [Indexed: 10/20/2022]
Abstract
Early in infection, adenovirus travels to the nucleus as a naked capsid using the microtubule motor cytoplasmic dynein. How the dynein complex is recruited to viral cargo remains unclear. We find that cytoplasmic dynein and its associated proteins dynactin and NudE/NudEL, but not LIS1 or ZW10, colocalized with incoming, postendosomal adenovirus particles. However, in contrast to physiological cargos, dynein binding to adenovirus was independent of these dynein-associated proteins. Dynein itself directly interacted through its intermediate and light intermediate chains with the adenovirus capsid subunit hexon in a pH-dependent manner. Expression of hexon or injection of anti-hexon antibody inhibited virus transport but not physiological dynein function. These results identify hexon as a direct receptor for cytoplasmic dynein and demonstrate that hexon recruits dynein for transport to the nucleus by a mechanism distinct from that for physiological dynein cargo.
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Affiliation(s)
- K Helen Bremner
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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24
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Ugai H, Wang M, Le LP, Matthews DA, Yamamoto M, Curiel DT. In vitro dynamic visualization analysis of fluorescently labeled minor capsid protein IX and core protein V by simultaneous detection. J Mol Biol 2010; 395:55-78. [PMID: 19853616 PMCID: PMC2787850 DOI: 10.1016/j.jmb.2009.10.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 09/29/2009] [Accepted: 10/14/2009] [Indexed: 10/20/2022]
Abstract
Oncolytic adenoviruses represent a promising therapeutic medicine for human cancer therapy, but successful translation into human clinical trials requires careful evaluation of their viral characteristics. While the function of adenovirus proteins has been analyzed in detail, the dynamics of adenovirus infection remain largely unknown due to technological constraints that prevent adequate tracking of adenovirus particles after infection. Fluorescence labeling of adenoviral particles is one new strategy designed to directly analyze the dynamic processes of viral infection in virus-host cell interactions. We hypothesized that the double labeling of an adenovirus with fluorescent proteins would allow us to properly analyze intracellular viruses and the fate of viral proteins in a live analysis of an adenovirus as compared to single labeling. Thus, we generated a fluorescently labeled adenovirus with both a red fluorescent minor capsid protein IX (pIX) [pIX monomeric red fluorescent protein 1 (mRFP1)] and a green fluorescent minor core protein V (pV) [pV enhanced green fluorescent protein (EGFP)], resulting in Ad5-IX-mRFP1-E3-V-EGFP. The fluorescent signals for pIX-mRFP1 and pV-EGFP were detected within 10 min in living cells. However, a growth curve analysis of Ad5-IX-mRFP1-E3-V-EGFP showed an approximately 150-fold reduced production of the viral progeny at 48 h postinfection as compared to adenovirus type 5. Interestingly, pIX-mRFP1 and pV-EGFP were initially localized in the cytoplasm and nucleolus, respectively, at 18 h postinfection. These proteins were observed in the nucleus during the late stage of infection, and relocalization of the proteins was observed in an adenoviral-replication-dependent manner. These results indicate that simultaneous detection of adenoviruses using dual-fluorescent proteins is suitable for real-time analysis, including identification of infected cells and monitoring of viral spread, which will be required for a complete evaluation of oncolytic adenoviruses.
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Affiliation(s)
- Hideyo Ugai
- Division of Human Gene Therapy, Department of Medicine, Obstetrics and Gynecology, Pathology, and Surgery, and the Gene Therapy Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Minghui Wang
- Division of Human Gene Therapy, Department of Medicine, Obstetrics and Gynecology, Pathology, and Surgery, and the Gene Therapy Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Long P. Le
- Massachusetts General Hospital, Pathology Service, 55 Fruit St.-GRJ 249, Boston, MA 02114, USA
| | - David A. Matthews
- Department of Cellular and Molecular Medicine, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK
| | - Masato Yamamoto
- Division of Basic and Translational Research, Department of Surgery, University of Minnesota, Minneapolis, MN 55455, USA
| | - David T. Curiel
- Division of Human Gene Therapy, Department of Medicine, Obstetrics and Gynecology, Pathology, and Surgery, and the Gene Therapy Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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25
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Lam YW, Evans VC, Heesom KJ, Lamond AI, Matthews DA. Proteomics analysis of the nucleolus in adenovirus-infected cells. Mol Cell Proteomics 2009; 9:117-30. [PMID: 19812395 PMCID: PMC2808258 DOI: 10.1074/mcp.m900338-mcp200] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Adenoviruses replicate primarily in the host cell nucleus, and it is well
established that adenovirus infection affects the structure and function of host
cell nucleoli in addition to coding for a number of nucleolar targeted viral
proteins. Here we used unbiased proteomics methods, including high throughput
mass spectrometry coupled with stable isotope labeling by amino acids in cell
culture (SILAC) and traditional two-dimensional gel electrophoresis, to identify
quantitative changes in the protein composition of the nucleolus during
adenovirus infection. Two-dimensional gel analysis revealed changes in six
proteins. By contrast, SILAC-based approaches identified 351 proteins with 24
proteins showing at least a 2-fold change after infection. Of those, four were
previously reported to have aberrant localization and/or functional relevance
during adenovirus infection. In total, 15 proteins identified as changing in
amount by proteomics methods were examined in infected cells using confocal
microscopy. Eleven of these proteins showed altered patterns of localization in
adenovirus-infected cells. Comparing our data with the effects of actinomycin D
on the nucleolar proteome revealed that adenovirus infection apparently
specifically targets a relatively small subset of nucleolar antigens at the time
point examined.
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Affiliation(s)
- Yun W Lam
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, China
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26
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Abstract
Viruses are intracellular pathogens that have to usurp some of the cellular machineries to provide an optimal environment for their own replication. An increasing number of reports reveal that many viruses induce modifications of nuclear substructures including nucleoli, whether they replicate or not in the nucleus of infected cells. Indeed, during infection of cells with various types of human viruses, nucleoli undergo important morphological modifications. A large number of viral components traffic to and from the nucleolus where they interact with different cellular and/or viral factors, numerous host nucleolar proteins are redistributed in other cell compartments or are modified and some cellular proteins are delocalised in the nucleolus of infected cells. Well‐documented studies have established that several of these nucleolar modifications play a role in some steps of the viral cycle, and also in fundamental cellular pathways. The nucleolus itself is the place where several essential steps of the viral cycle take place. In other cases, viruses divert host nucleolar proteins from their known functions in order to exert new unexpected role(s). Copyright © 2009 John Wiley & Sons, Ltd.
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Affiliation(s)
- Anna Greco
- Université de Lyon, Lyon F-69003, France.
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27
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Abstract
DNA-tumor viruses comprise enveloped and non-enveloped agents that cause malignancies in a large variety of cell types and tissues by interfering with cell cycle control and immortalization. Those DNA-tumor viruses that replicate in the nucleus use cellular mechanisms to transport their genome and newly synthesized viral proteins into the nucleus. This requires cytoplasmic transport and nuclear import of their genome. Agents that employ this strategy include adenoviruses, hepadnaviruses, herpesviruses, and likely also papillomaviruses, and polyomaviruses, but not poxviruses which replicate in the cytoplasm. Here, we discuss how DNA-tumor viruses enter cells, take advantage of cytoplasmic transport, and import their DNA genome through the nuclear pore complex into the nucleus. Remarkably, nuclear import of incoming genomes does not necessarily follow the same pathways used by the structural proteins of the viruses during the replication and assembly phases of the viral life cycle. Understanding the mechanisms of DNA nuclear import can identify new pathways of cell regulation and anti-viral therapies.
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Affiliation(s)
- Urs F Greber
- Institute of Zoology, University of Zürich, Switzerland
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28
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Abstract
Adenoviruses have been studied intensively for over 50 years as models of virus-cell interactions and latterly as gene vectors. With the advent of more sophisticated structural analysis techniques the disposition of most of the 13 structural proteins have been defined to a reasonable level. This review seeks to describe the functional properties of these proteins and shows that they all have a part to play in deciding the outcome of an infection and act at every level of the virus's path through the host cell. They are primarily involved in the induction of the different arms of the immune system and a better understanding of their overall properties should lead to more effective ways of combating virus infections.
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Affiliation(s)
- W C Russell
- School of Biology, Biomolecular Sciences Building, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.
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29
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Abstract
Adenoviruses target their double-stranded DNA genome and its associated core proteins to the interphase nucleus; this core structure then enters through the nuclear pore complex. We have used digitonin permeabilized cell import assays to study the cellular import factors involved in nuclear entry of virus DNA and the core proteins, protein V and protein VII. We show that inhibition of transportin results in aberrant localization of protein V and that transportin is necessary for protein V to accumulate in the nucleolus. Furthermore, inhibition of transportin results in inhibition of protein VII and DNA import, whereas disruption of the classical importin α–importin β import pathway has little effect. We show that mature protein VII has different import preferences from the precursor protein, preVII from which it is derived by proteolytic processing. While bacterially expressed glutathione S-transferase (GST)-preVII primarily utilizes the pathway mediated by importin α–importin β, bacterially expressed GST-VII favours the transportin pathway. This is significant because while preVII is important during viral replication and assembly only mature VII is available during viral DNA import to a newly infected cell. Our results implicate transportin as a key import receptor for the nuclear localization of adenovirus core.
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30
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Tollefson AE, Ying B, Doronin K, Sidor PD, Wold WSM. Identification of a new human adenovirus protein encoded by a novel late l-strand transcription unit. J Virol 2007; 81:12918-26. [PMID: 17881437 PMCID: PMC2169129 DOI: 10.1128/jvi.01531-07] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A short open reading frame named the "U exon," located on the adenovirus (Ad) l-strand (for leftward transcription) between the early E3 region and the fiber gene, is conserved in mastadenoviruses. We have observed that Ad5 mutants with large deletions in E3 that infringe on the U exon display a mild growth defect, as well as an aberrant Ad E2 DNA-binding protein (DBP) intranuclear localization pattern and an apparent failure to organize replication centers during late infection. Mutants in which the U exon DNA is reconstructed have a reversed phenotype. Chow et al. (L. T. Chow et al., J. Mol. Biol. 134:265-303, 1979) described mRNAs initiating in the region of the U exon and spliced to downstream sequences in the late DBP mRNA leader and the DBP-coding region. We have cloned this mRNA (as cDNA) from Ad5 late mRNA; the predicted protein is 217 amino acids, initiating in the U exon and continuing in frame in the DBP leader and in the DBP-coding region but in a different reading frame from DBP. Polyclonal and monoclonal antibodies generated against the predicted U exon protein (UXP) showed that UXP is approximately 24K in size by immunoblot and is a late protein. At 18 to 24 h postinfection, UXP is strongly associated with nucleoli and is found throughout the nucleus; later, UXP is associated with the periphery of replication centers, suggesting a function relevant to Ad DNA replication or RNA transcription. UXP is expressed by all four species C Ads. When expressed in transient transfections, UXP complements the aberrant DBP localization pattern of UXP-negative Ad5 mutants. Our data indicate that UXP is a previously unrecognized protein derived from a novel late l-strand transcription unit.
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Affiliation(s)
- Ann E Tollefson
- Department of Molecular Microbiology and Immunology, St. Louis University Health Sciences Center, 1100 South Grand Blvd., St. Louis, MO 63104, USA
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31
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Matthews DA. Study of nucleolar localization of adenovirus core proteins. METHODS IN MOLECULAR MEDICINE 2007; 131:73-81. [PMID: 17656776 DOI: 10.1007/978-1-59745-277-9_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
This chapter describes the techniques used to study nucleolar-localized proteins. The chapter starts with cloning of viral proteins for expression in mammalian cells as fusion proteins to well-characterized tags such as enhanced green fluorescence protein (EGFP). This follows on to techniques for transient expression in mammalian cells and immunofluorescence techniques used to examine subcellular localization. Finally there is guidance on the types of antigens and metabolic features of the nucleolus that can be used as markers to confirm that the protein in question is indeed localized in the nucleolus and determine whether it affects gross rRNA synthesis.
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32
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Spector DJ. Default assembly of early adenovirus chromatin. Virology 2007; 359:116-25. [PMID: 17034827 DOI: 10.1016/j.virol.2006.09.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 08/23/2006] [Accepted: 09/06/2006] [Indexed: 11/17/2022]
Abstract
In adenovirus particles, the viral nucleoprotein is organized into a highly compacted core structure. Upon delivery to the nucleus, the viral nucleoprotein is very likely to be remodeled to a form accessible to the transcription and replication machinery. Viral protein VII binds to intra-nuclear viral DNA, as do at least two cellular proteins, SET/TAF-Ibeta and pp32, components of a chromatin assembly complex that is implicated in template remodeling. We showed previously that viral DNA-protein complexes released from infecting particles were sensitive to shearing after cross-linking with formaldehyde, presumably after transport of the genome into the nucleus. We report here the application of equilibrium-density gradient centrifugation to the analysis of the fate of these complexes. Most of the incoming protein VII was recovered in a form that was not cross-linked to viral DNA. This release of protein VII, as well as the binding of SET/TAF-Ibeta and cellular transcription factors to the viral chromatin, did not require de novo viral gene expression. The distinct density profiles of viral DNA complexes containing protein VII, compared to those containing SET/TAF-Ibeta or transcription factors, were consistent with the notion that the assembly of early viral chromatin requires both the association of SET/TAF-1beta and the release of protein VII.
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Affiliation(s)
- David J Spector
- Department of Microbiology and Immunology, Pennsylvania State University College of Hershey, PA 17033, USA.
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Hama S, Akita H, Iida S, Mizuguchi H, Harashima H. Quantitative and mechanism-based investigation of post-nuclear delivery events between adenovirus and lipoplex. Nucleic Acids Res 2007; 35:1533-43. [PMID: 17287293 PMCID: PMC1865055 DOI: 10.1093/nar/gkl1165] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Quantitative and mechanism-based information on differences in transfection efficiency between viral and non-viral vectors would be highly useful for improving the effectiveness of non-viral vectors. A previous quantitative comparison of intracellular trafficking between adenovirus and LipofectAMINE PLUS (LFN) revealed that the three orders of magnitude lower transfection efficiency of LFN was dominantly rate limited by the post-nuclear delivery process. In the present study, the contribution of transcription and translation processes to the overall differences in the transgene expression efficiency of nucleus-delivered DNA was independently evaluated by quantifying mRNA. As a result, transcription efficiency (Etranscript) of LFN, denoted as transgene expression divided by the amount of nuclear pDNA was about 16 times less than that for adenovirus. Furthermore, translation efficiency (Etranslate), denoted as transfection activity divided by mRNA expression was approximately 460 times less in LFN. Imaging of the decondensed form of DNA by in situ hybridization revealed that poor decondensation efficiency of LFN is involved in the inferior Etranscript. Moreover, the inferior translation efficiency (Etranslate) of LFN was mainly due to electrostatic interactions between LFN and mRNA. Collectively, an improvement in nuclear decondensation and the diminution of the interaction between vector and mRNA is essential for the development of new generations of non-viral vectors.
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Affiliation(s)
- Susumu Hama
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan, Laboratory of Gene Transfer and Regulation, National Institute of Biomedical Innovation, Osaka 567-0085, Japan and CREST, Japan Science and Technology Corporation (JST), Japan
| | - Hidetaka Akita
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan, Laboratory of Gene Transfer and Regulation, National Institute of Biomedical Innovation, Osaka 567-0085, Japan and CREST, Japan Science and Technology Corporation (JST), Japan
| | - Shinya Iida
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan, Laboratory of Gene Transfer and Regulation, National Institute of Biomedical Innovation, Osaka 567-0085, Japan and CREST, Japan Science and Technology Corporation (JST), Japan
| | - Hiroyuki Mizuguchi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan, Laboratory of Gene Transfer and Regulation, National Institute of Biomedical Innovation, Osaka 567-0085, Japan and CREST, Japan Science and Technology Corporation (JST), Japan
| | - Hideyoshi Harashima
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Hokkaido 060-0812, Japan, Laboratory of Gene Transfer and Regulation, National Institute of Biomedical Innovation, Osaka 567-0085, Japan and CREST, Japan Science and Technology Corporation (JST), Japan
- *To whom correspondence should be addressed. +81 11 706 3919+81 11 706 4879
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34
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Lawrence FJ, McStay B, Matthews DA. Nucleolar protein upstream binding factor is sequestered into adenovirus DNA replication centres during infection without affecting RNA polymerase I location or ablating rRNA synthesis. J Cell Sci 2006; 119:2621-31. [PMID: 16763197 DOI: 10.1242/jcs.02982] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
When human adenovirus infects human cells there is disruption of rRNA biogenesis. This report examines the effect of adenovirus infection on the nucleolar protein, upstream binding factor (UBF) which plays a major role in regulating rRNA synthesis. We determined that early after infection, UBF associates with the replication of viral DNA, preferentially associating with the ends of the linear viral genome, and that addition of anti-UBF serum to in vitro replication assays markedly reduced viral DNA replication. Regions of UBF important to these observations are also established. Interestingly, sequestering the majority of UBF from the nucleolus did not lead to the ablation of rRNA synthesis or the sequestration of RNA pol I. In infected cells the bulk of RNA synthesis was RNA pol I associated and distinct from the location of most of the detectable UBF. We propose that UBF plays a role in viral DNA replication, further strengthening the role of nucleolar antigens in the adenovirus life cycle.
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Affiliation(s)
- Fiona J Lawrence
- Division of Virology, Department of Cellular and Molecular Medicine, University Walk, University of Bristol, Bristol, BS8 1TD, UK
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35
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Wodrich H, Cassany A, D'Angelo MA, Guan T, Nemerow G, Gerace L. Adenovirus core protein pVII is translocated into the nucleus by multiple import receptor pathways. J Virol 2006; 80:9608-18. [PMID: 16973564 PMCID: PMC1617226 DOI: 10.1128/jvi.00850-06] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Adenoviruses are nonenveloped viruses with an approximately 36-kb double-stranded DNA genome that replicate in the nucleus. Protein VII, an abundant structural component of the adenovirus core that is strongly associated with adenovirus DNA, is imported into the nucleus contemporaneously with the adenovirus genome shortly after virus infection and may promote DNA import. In this study, we evaluated whether protein VII uses specific receptor-mediated mechanisms for import into the nucleus. We found that it contains potent nuclear localization signal (NLS) activity by transfection of cultured cells with protein VII fusion constructs and by microinjection of cells with recombinant protein VII fusions. We identified three NLS-containing regions in protein VII by deletion mapping and determined important NLS residues by site-specific mutagenesis. We found that recombinant protein VII and its NLS-containing domains strongly and specifically bind to importin alpha, importin beta, importin 7, and transportin, which are among the most abundant cellular nuclear import receptors. Moreover, these receptors can mediate the nuclear import of protein VII fusions in vitro in permeabilized cells. Considered together, these data support the hypothesis that protein VII is a major NLS-containing adaptor for receptor-mediated import of adenovirus DNA and that multiple import pathways are utilized to promote efficient nuclear entry of the viral genome.
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Affiliation(s)
- Harald Wodrich
- Institut de Génétique Moléculaire de Montpellier, UMR 5535 CNRS, 1919 Route de Mende, 34293 Montpellier Cedex 05, France.
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36
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Le LP, Le HN, Nelson AR, Matthews DA, Yamamoto M, Curiel DT. Core labeling of adenovirus with EGFP. Virology 2006; 351:291-302. [PMID: 16678874 PMCID: PMC1781517 DOI: 10.1016/j.virol.2006.03.042] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 12/15/2005] [Accepted: 03/21/2006] [Indexed: 11/27/2022]
Abstract
The study of adenovirus could greatly benefit from diverse methods of virus detection. Recently, it has been demonstrated that carboxy-terminal EGFP fusions of adenovirus core proteins Mu, V, and VII properly localize to the nucleus and display novel function in the cell. Based on these observations, we hypothesized that the core proteins may serve as targets for labeling the adenovirus core with fluorescent proteins. To this end, we constructed various chimeric expression vectors with fusion core genes (Mu-EGFP, V-EGFP, preVII-EGFP, and matVII-EGFP) while maintaining expression of the native proteins. Expression of the fusion core proteins was suboptimal using E1 expression vectors with both conventional CMV and modified (with adenovirus tripartite leader sequence) CMV5 promoters, resulting in non-labeled viral particles. However, robust expression equivalent to the native protein was observed when the fusion genes were placed in the deleted E3 region. The efficient Ad-wt-E3-V-EGFP and Ad-wt-E3-preVII-EGFP expression vectors were labeled allowing visualization of purified virus and tracking of the viral core during early infection. The vectors maintained their viral function, including viral DNA replication, viral DNA encapsidation, cytopathic effect, and thermostability. Core labeling offers a means to track the adenovirus core in vector targeting studies as well as basic adenovirus virology.
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Affiliation(s)
- Long P Le
- Division of Human Gene Therapy, Departments of Medicine, Pathology and Surgery, University of Alabama at Birmingham, 901 19th Street South, BMR2-502, Birmingham, AL 35294, USA
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37
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Libault M, Tessadori F, Germann S, Snijder B, Fransz P, Gaudin V. The Arabidopsis LHP1 protein is a component of euchromatin. PLANTA 2005; 222:910-25. [PMID: 16244868 DOI: 10.1007/s00425-005-0129-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2005] [Accepted: 08/29/2005] [Indexed: 05/05/2023]
Abstract
The HP1 family proteins are involved in several aspects of chromatin function and regulation in Drosophila, mammals and the fission yeast. Here we investigate the localization of LHP1, the unique Arabidopsis thaliana HP1 homolog known at present time, to approach its function. A functional LHP1-GFP fusion protein, able to restore the wild-type phenotype in the lhp1 mutant, was used to analyze the subnuclear distribution of LHP1 in both A. thaliana and Nicotiana tabacum. In A. thaliana interphase nuclei, LHP1 was predominantly located outside the heterochromatic chromocenters. No major aberrations were observed in heterochromatin content or chromocenter organization in lhp1 plants. These data indicate that LHP1 is mainly involved in euchromatin organization in A. thaliana. In tobacco BY-2 cells, the LHP1 distribution, although in foci, slightly differed suggesting that LHP1 localization is determined by the underlying genome organization of plant species. Truncated LHP1 proteins expressed in vivo allowed us to determine the function of the different segments in the localization. The in foci distribution is dependent on the presence of the two chromo domains, whereas the hinge region has some nucleolus-targeting properties. Furthermore, like the animal HP1beta and HP1gamma subtypes, LHP1 dissociates from chromosomes during mitosis. In transgenic plants expressing the LHP1-GFP fusion protein, two major localization patterns were observed according to cell types suggesting that localization evolves with age or differentiation states. Our results show conversed characteristics of the A. thaliana HP1 homolog with the mammal HP1gamma isoform, besides specific plant properties.
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Affiliation(s)
- Marc Libault
- Laboratoire de Biologie Cellulaire, IJPB, INRA, route de St Cyr, 78026, Versailles Cedex, France
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38
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Wang YH, Chen YH, Lu JH, Tsai HJ. A 23-amino acid motif spanning the basic domain targets zebrafish myogenic regulatory factor myf5 into nucleolus. DNA Cell Biol 2005; 24:651-60. [PMID: 16225396 DOI: 10.1089/dna.2005.24.651] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Myf5 is a nuclear protein and one of the basic helix-loop-helix (bHLH) myogenic factors that play an important role in muscle specification and differentiation. The motif responsible for the nuclear translocation of Myf5 was unknown. Using on-line monitoring of EGFP (enhanced green fluorescent protein)-tagged zebrafish Myf5 translocation, we demonstrated that Myf5-EGFP protein resided in the nucleoplasm and nucleolus of zebrafish fibroblast cell lines (ZEM2S and ZF4), mammalian nonmuscle cell line (COS1), and muscle cell lines (RD and C2C12). In contrast, zebrafish MyoD-EGFP was localized in the nucleus but did not condense in the nucleolus. Using indirect immunofluorescent staining, we determined that zebrafish Myf5 was colocalized with nucleophosmin/B23, a nucleolus protein. Deletion analysis revealed that amino acid residues 60 to 82 (60KRKASTVDRRRAATMRERRRLKK82) of Myf5 were sufficient and necessary for nucleolus targeting. A GST pulldown assay followed by Western analysis showed that nucleolin/C23 could be pulled down specifically by GST-Myf5, but not by GST-MyoD. Based on these findings, we propose that the distinct functions of Myf5 and MyoD may result from their differential binding affinity to nucleolin/C23.
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Affiliation(s)
- Yun-Hsin Wang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan, Republic of China.
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39
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Abstract
Gene therapy holds promise for the treatment of a range of inherited diseases, such as cystic fibrosis. However, efficient delivery and expression of the therapeutic transgene at levels sufficient to result in phenotypic correction of cystic fibrosis pulmonary disease has proved elusive. There are many reasons for this lack of progress, both macroscopically in terms of airway defence mechanisms and at the molecular level with regard to effective cDNA delivery. This review of approaches to cystic fibrosis gene therapy covers these areas in detail and highlights recent progress in the field. For gene therapy to be effective in patients with cystic fibrosis, the cDNA encoding the cystic fibrosis transmembrane conductance regulator protein must be delivered effectively to the nucleus of the epithelial cells lining the bronchial tree within the lungs. Expression of the transgene must be maintained at adequate levels for the lifetime of the patient, either by repeat dosage of the vector or by targeting airway stem cells. Clinical trials of gene therapy for cystic fibrosis have demonstrated proof of principle, but gene expression has been limited to 30 days at best. Results suggest that viral vectors such as adenovirus and adeno-associated virus are unsuited to repeat dosing, as the immune response reduces the effectiveness of each subsequent dose. Nonviral approaches, such as cationic liposomes, appear more suited to repeat dosing, but have been less effective. Current work regarding non-viral gene delivery is now focused on understanding the mechanisms involved in cell entry, endosomal escape and nuclear import of the transgene. There is now increasing evidence to suggest that additional ligands that facilitate endosomal escape or contain a nuclear localization signal may enhance liposome-mediated gene delivery. Much progress in this area has been informed by advances in our understanding of the mechanisms by which viruses deliver their genomes to the nuclei of host cells.
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Affiliation(s)
- Tim W R Lee
- School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
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40
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Zhang W, Arcos R. Interaction of the adenovirus major core protein precursor, pVII, with the viral DNA packaging machinery. Virology 2005; 334:194-202. [PMID: 15780869 DOI: 10.1016/j.virol.2005.01.048] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 12/20/2004] [Accepted: 01/28/2005] [Indexed: 10/25/2022]
Abstract
Adenovirus is one of the well-studied double-stranded DNA viruses. However, the mechanisms of its DNA packaging and virion assembly are still not fully understood. One of the unique features of adenovirus is that the unpackaged viral DNA is associated with core protein pVII. Packaging of viral DNA bound with proteins has not been reported from other viruses. To characterize how viral DNA bound with protein pVII is packaged, we performed experiments to see if protein pVII interacts with the known DNA packaging proteins or the packaging sequence. Our results demonstrated that protein pVII interacted with the viral IVa2 and L1 52/55 kDa proteins, which are the known viral DNA packaging proteins. Furthermore, our protein-DNA binding experiments demonstrated that the IVa2 protein mediates the specific interaction with the packaging sequence, whereas protein pVII and the L1 52/55 kDa protein bind to DNA non-specifically. Although the non-specific binding of protein pVII and the L1 52/55 kDa protein do not appear to affect the specific binding of the IVa2 protein to the packaging sequence, and the specific binding of the IVa2 protein does not appear to block the bindings of protein pVII and the L1 52/55 kDa protein to the packaging sequence, the possibility of a cooperative binding among the IVa2 protein, the L1 52/55 kDa protein and protein pVII on the packaging sequence needs to be further determined. In summary, the results indicate that the assembly of the DNA packaging initiation complex may be mediated by the specific interaction of the IVa2 protein with the packaging sequence and other viral proteins, such as protein pVII and the L1 52/55 kDa protein.
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Affiliation(s)
- Wei Zhang
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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41
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Miron MJ, Gallouzi IE, Lavoie JN, Branton PE. Nuclear localization of the adenovirus E4orf4 protein is mediated through an arginine-rich motif and correlates with cell death. Oncogene 2004; 23:7458-68. [PMID: 15334069 DOI: 10.1038/sj.onc.1207919] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The adenovirus E4orf4 protein induces p53-independent death of human cancer cells by a mechanism requiring interactions with the Balpha subunit of protein phosphatase 2A. When expressed alone E4orf4 localizes predominantly in the nucleus, although significant levels are also present in the cytoplasm. While tyrosine phosphorylation of E4orf4 and recruitment of Src have been linked with E4orf4 cytoplasmic cell death functions, little is known about the functions of E4orf4 in the nucleus. In this study, we identified an arginine-rich motif (E4ARM; residues 66-75) that is necessary and sufficient for nuclear and nucleolar localization. This motif, which is highly homologous to the arginine-rich nuclear and nucleolar localization motif of some lentiviral proteins, was shown to target heterologous proteins to the nucleus and to nucleoli, functions found to be dependent on the overall charge of the motif rather than on specific residues. Furthermore, mutation of arginine residues to alanines but not to lysines in E4ARM was shown to block such targeting activity and, when introduced into full-length E4orf4, to decrease induction of cell death. Finally, coexpression of the ARM motifs of E4orf4, HIV-1 Tat or Rev along with full-length E4orf4 was seen to decrease E4orf4-dependent cell killing. Thus it appears that targeting of E4orf4 to the nucleus and cell nucleoli by E4ARM is an important component of E4orf4-induced cell death.
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Affiliation(s)
- Marie-Joëlle Miron
- Department of Biochemistry, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
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42
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Kovács GM, Davison AJ, Zakhartchouk AN, Harrach B. Analysis of the first complete genome sequence of an Old World monkey adenovirus reveals a lineage distinct from the six human adenovirus species. J Gen Virol 2004; 85:2799-2807. [PMID: 15448340 DOI: 10.1099/vir.0.80225-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Simian adenovirus 3 (SAdV-3) is one of several adenoviruses that were isolated decades ago from Old World monkeys. Determination of the complete DNA sequence of SAdV-3 permitted the first full genomic comparison of a monkey adenovirus with adenoviruses of humans (HAdVs) and chimpanzees, which are recognized formally as constituting six of the species (HAdV-A to HAdV-F) within the genus Mastadenovirus. The SAdV-3 genome is 34 246 bp in size and has a G+C content of 55.3 mol%. It contains all the genes that are characteristic of the genus Mastadenovirus and has a single VA-RNA gene and six genes in each of the E3 and E4 regions. The genetic organization is the same as that of HAdV-12, a member of the HAdV-A species. Phylogenetic analyses showed that although SAdV-3 is related marginally more closely to HAdV-A and HAdV-F than to other species, it represents a unique lineage that branched at an early stage of primate adenovirus divergence. The results imply that the genetic layout in SAdV-3 and HAdV-12 may also have characterized the common ancestor of all sequenced primate adenoviruses.
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Affiliation(s)
- Gábor M Kovács
- Veterinary Medical Research Institute, Hungarian Academy of Sciences, PO Box 18, H-1581 Budapest, Hungary
| | - Andrew J Davison
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, UK
| | - Alexender N Zakhartchouk
- Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3
| | - Balázs Harrach
- Veterinary Medical Research Institute, Hungarian Academy of Sciences, PO Box 18, H-1581 Budapest, Hungary
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