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Pena-Francesch M, Vanoaica LD, Zhu GF, Stumpe M, Sankar DS, Nowag H, Valencia-Camargo AD, Hammerschmidt W, Dengjel J, Ligeon LA, Münz C. The autophagy machinery interacts with EBV capsids during viral envelope release. Proc Natl Acad Sci U S A 2023; 120:e2211281120. [PMID: 37579175 PMCID: PMC10451551 DOI: 10.1073/pnas.2211281120] [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: 07/08/2022] [Accepted: 06/02/2023] [Indexed: 08/16/2023] Open
Abstract
Autophagy serves as a defense mechanism against intracellular pathogens, but several microorganisms exploit it for their own benefit. Accordingly, certain herpesviruses include autophagic membranes into their infectious virus particles. In this study, we analyzed the composition of purified virions of the Epstein-Barr virus (EBV), a common oncogenic γ-herpesvirus. In these, we found several components of the autophagy machinery, including membrane-associated LC3B-II, and numerous viral proteins, such as the capsid assembly proteins BVRF2 and BdRF1. Additionally, we showed that BVRF2 and BdRF1 interact with LC3B-II via their common protein domain. Using an EBV mutant, we identified BVRF2 as essential to assemble mature capsids and produce infectious EBV. However, BdRF1 was sufficient for the release of noninfectious viral envelopes as long as autophagy was not compromised. These data suggest that BVRF2 and BdRF1 are not only important for capsid assembly but together with the LC3B conjugation complex of ATG5-ATG12-ATG15L1 are also critical for EBV envelope release.
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Affiliation(s)
- Maria Pena-Francesch
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich8057, Switzerland
| | - Liliana Danusia Vanoaica
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich8057, Switzerland
| | - Gao-Feng Zhu
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich8057, Switzerland
| | - Michael Stumpe
- Department of Biology, University of Fribourg, Fribourg1700, Switzerland
| | | | - Heike Nowag
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich8057, Switzerland
| | | | - Wolfgang Hammerschmidt
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research, D-81377Munich, Germany
| | - Jörn Dengjel
- Department of Biology, University of Fribourg, Fribourg1700, Switzerland
| | - Laure-Anne Ligeon
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich8057, Switzerland
| | - Christian Münz
- Viral Immunobiology, Institute of Experimental Immunology, University of Zürich, Zürich8057, Switzerland
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2
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Regulation of Epstein-Barr Virus Minor Capsid Protein BORF1 by TRIM5α. Int J Mol Sci 2022; 23:ijms232315340. [PMID: 36499678 PMCID: PMC9735550 DOI: 10.3390/ijms232315340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 11/16/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022] Open
Abstract
TRIM5α is a host anti-retroviral restriction factor that destroys human immunodeficiency virus (HIV) virions and triggers innate immune signaling. TRIM5α also mediates the autophagic degradation of target proteins via TRIMosome formation. We previously showed that TRIM5α promotes Epstein-Barr virus (EBV) Rta ubiquitination and attenuates EBV lytic progression. In this study, we sought to elucidate whether TRIM5α can interact with and induce the degradation of EBV capsid proteins. Glutathione S-transferase (GST) pulldown and immunoprecipitation assays were conducted to identify interacting proteins, and mutants were generated to investigate key binding domains and ubiquitination sites. Results showed that TRIM5α binds directly with BORF1, an EBV capsid protein with a nuclear localization signal (NLS) that enables the transport of EBV capsid proteins into the host nucleus to facilitate capsid assembly. TRIM5α promotes BORF1 ubiquitination, which requires the surface patch region in the TRIM5α PRY/SPRY domain. TRIM5α expression also decreases the stability of BORF1(6KR), a mutant with all lysine residues mutated to arginine. However, chloroquine treatment restores the stability of BORF1(6KR), suggesting that TRIM5α destabilizes BORF1 via direct recognition of its substrate for autophagic degradation. These results reveal novel insights into the antiviral impact of TRIM5α beyond retroviruses.
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Lee CP, Chen MR. Conquering the Nuclear Envelope Barriers by EBV Lytic Replication. Viruses 2021; 13:702. [PMID: 33919628 PMCID: PMC8073350 DOI: 10.3390/v13040702] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 12/14/2022] Open
Abstract
The nuclear envelope (NE) of eukaryotic cells has a highly structural architecture, comprising double lipid-bilayer membranes, nuclear pore complexes, and an underlying nuclear lamina network. The NE structure is held in place through the membrane-bound LINC (linker of nucleoskeleton and cytoskeleton) complex, spanning the inner and outer nuclear membranes. The NE functions as a barrier between the nucleus and cytoplasm and as a transverse scaffold for various cellular processes. Epstein-Barr virus (EBV) is a human pathogen that infects most of the world's population and is associated with several well-known malignancies. Within the nucleus, the replicated viral DNA is packaged into capsids, which subsequently egress from the nucleus into the cytoplasm for tegumentation and final envelopment. There is increasing evidence that viral lytic gene expression or replication contributes to the pathogenesis of EBV. Various EBV lytic proteins regulate and modulate the nuclear envelope structure in different ways, especially the viral BGLF4 kinase and the nuclear egress complex BFRF1/BFRF2. From the aspects of nuclear membrane structure, viral components, and fundamental nucleocytoplasmic transport controls, this review summarizes our findings and recently updated information on NE structure modification and NE-related cellular processes mediated by EBV.
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Affiliation(s)
- Chung-Pei Lee
- School of Nursing, National Taipei University of Nursing and Health Sciences, Taipei 112303, Taiwan;
| | - Mei-Ru Chen
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei 100233, Taiwan
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4
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The Epstein-Barr Virus Lytic Protein BMLF1 Induces Upregulation of GRP78 Expression through ATF6 Activation. Int J Mol Sci 2021; 22:ijms22084024. [PMID: 33919712 PMCID: PMC8070695 DOI: 10.3390/ijms22084024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 11/17/2022] Open
Abstract
The unfolded protein response (UPR) is an intracellular signaling pathway essential for alleviating the endoplasmic reticulum (ER) stress. To support the productive infection, many viruses are known to use different strategies to manipulate the UPR signaling network. However, it remains largely unclear whether the UPR signaling pathways are modulated in the lytic cycle of Epstein-Barr virus (EBV), a widely distributed human pathogen. Herein, we show that the expression of GRP78, a central UPR regulator, is up-regulated during the EBV lytic cycle. Our data further revealed that knockdown of GRP78 in EBV-infected cell lines did not substantially affect lytic gene expression; however, GRP78 knockdown in these cells markedly reduced the production of virus particles. Importantly, we identified that the early lytic protein BMLF1 is the key regulator critically contributing to the activation of the grp78 gene promoter. Mechanistically, we found that BMLF1 can trigger the proteolytic cleavage and activation of the UPR senor ATF6, which then transcriptionally activates the grp78 promoter through the ER stress response elements. Our findings therefore provide evidence for the connection between the EBV lytic cycle and the UPR, and implicate that the BMLF1-mediated ATF6 activation may play critical roles in EBV lytic replication.
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5
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Wyżewski Z, Świtlik W, Mielcarska MB, Gregorczyk-Zboroch KP. The Role of Bcl-xL Protein in Viral Infections. Int J Mol Sci 2021; 22:ijms22041956. [PMID: 33669408 PMCID: PMC7920434 DOI: 10.3390/ijms22041956] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/13/2021] [Accepted: 02/14/2021] [Indexed: 02/06/2023] Open
Abstract
Bcl-xL represents a family of proteins responsible for the regulation of the intrinsic apoptosis pathway. Due to its anti-apoptotic activity, Bcl-xL co-determines the viability of various virally infected cells. Their survival may determine the effectiveness of viral replication and spread, dynamics of systemic infection, and viral pathogenesis. In this paper, we have reviewed the role of Bcl-xL in the context of host infection by eight different RNA and DNA viruses: hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), influenza A virus (IAV), Epstein-Barr virus (EBV), human T-lymphotropic virus type-1 (HTLV-1), Maraba virus (MRBV), Schmallenberg virus (SBV) and coronavirus (CoV). We have described an influence of viral infection on the intracellular level of Bcl-xL and discussed the impact of Bcl-xL-dependent cell survival control on infection-accompanying pathogenic events such as tissue damage or oncogenesis. We have also presented anti-viral treatment strategies based on the pharmacological regulation of Bcl-xL expression or activity.
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Affiliation(s)
- Zbigniew Wyżewski
- Institute of Biological Sciences, Cardinal Stefan Wyszyński University in Warsaw, 01-815 Warsaw, Poland
- Correspondence: ; Tel.: +48 728-208-338
| | - Weronika Świtlik
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences-SGGW, 02-787 Warsaw, Poland;
| | - Matylda Barbara Mielcarska
- Institute of Veterinary Medicine, Warsaw University of Life Sciences, 02-787 Warsaw, Poland; (M.B.M.); (K.P.G.-Z.)
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6
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The Role of ND10 Nuclear Bodies in Herpesvirus Infection: A Frenemy for the Virus? Viruses 2021; 13:v13020239. [PMID: 33546431 PMCID: PMC7913651 DOI: 10.3390/v13020239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/28/2021] [Accepted: 01/28/2021] [Indexed: 11/19/2022] Open
Abstract
Nuclear domains 10 (ND10), a.k.a. promyelocytic leukemia nuclear bodies (PML-NBs), are membraneless subnuclear domains that are highly dynamic in their protein composition in response to cellular cues. They are known to be involved in many key cellular processes including DNA damage response, transcription regulation, apoptosis, oncogenesis, and antiviral defenses. The diversity and dynamics of ND10 residents enable them to play seemingly opposite roles under different physiological conditions. Although the molecular mechanisms are not completely clear, the pro- and anti-cancer effects of ND10 have been well established in tumorigenesis. However, in herpesvirus research, until the recently emerged evidence of pro-viral contributions, ND10 nuclear bodies have been generally recognized as part of the intrinsic antiviral defenses that converge to the incoming viral DNA to inhibit the viral gene expression. In this review, we evaluate the newly discovered pro-infection influences of ND10 in various human herpesviruses and analyze their molecular foundation along with the traditional antiviral functions of ND10. We hope to shed light on the explicit role of ND10 in both the lytic and latent cycles of herpesvirus infection, which is imperative to the delineation of herpes pathogenesis and the development of prophylactic/therapeutic treatments for herpetic diseases.
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7
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Huang HH, Wang WH, Feng TH, Chang LK. Rta is an Epstein-Barr virus tegument protein that improves the stability of capsid protein BORF1. Biochem Biophys Res Commun 2020; 523:773-779. [PMID: 31948747 DOI: 10.1016/j.bbrc.2020.01.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 01/05/2020] [Indexed: 11/30/2022]
Abstract
Rta, a key transcription factor expressed by Epstein-Barr virus (EBV), primarily acts to induce activation of the EBV lytic cycle. Interestingly, we observed from an immunogold assay that Rta is also present on the EBV capsid in the host cell nucleus, and a centrifugation study further revealed that Rta cofractionates with EBV virions. Importantly, cofractionated Rta showed similar properties as the EBV tegument protein, BGLF4. Glutathione S-transferase (GST)-pulldown and coimmunoprecipitation assays subsequently demonstrated that Rta directly interacts with the EBV capsid protein, BORF1. Rta was observed to colocalize with BORF1 in the nucleus during EBV lytic induction, and this interaction appears to influence BORF1 stability. Moreover, we found that BORF1 is modified by ubiquitin, and Rta reduces this ubiquitination. These results indicate that Rta may act as an inner tegument protein to improve EBV capsid stability and critical to viral infection.
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Affiliation(s)
- Hsiang-Hung Huang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Wen-Hung Wang
- Division of Infectious Disease, Department of Internal Medicine, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan; Center for Tropical Medicine and Infectious Disease Research, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Tzu-Hui Feng
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Li-Kwan Chang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan.
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8
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Hung CH, Chiu YF, Wang WH, Chen LW, Chang PJ, Huang TY, Lin YJ, Tsai WJ, Yang CC. Interaction Between BGLF2 and BBLF1 Is Required for the Efficient Production of Infectious Epstein-Barr Virus Particles. Front Microbiol 2020; 10:3021. [PMID: 32038519 PMCID: PMC6993569 DOI: 10.3389/fmicb.2019.03021] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 12/17/2019] [Indexed: 11/13/2022] Open
Abstract
BGLF2 is a tegument protein of the Epstein-Barr virus (EBV). This study finds that BGLF2 is expressed in the late stage of the EBV lytic cycle. Microscopic investigations reveal that BGLF2 is present in both the nucleus and the cytoplasm and colocalized with BBLF1 and gp350 at juxtanuclear regions in the cytoplasm. This study also finds that the basic KKK69 motif of BGLF2 and acidic DYEE31 motif of BBLF1 are crucial for the interaction between BGLF2 and BBLF1, which is required for the recruitment of BGLF2 to the BBLF1 that is anchored on the trans-Golgi-network (TGN). In addition, BGLF2 in a density gradient is co-sedimented with un-enveloped capsids, revealing that BGLF2 associates with the EBV capsid before the final envelopment. The knockout of BGLF2 expression is demonstrated to reduce the numbers of infectious virions that are released into the culture medium, but they do not affect the expression of lytic proteins and viral DNA replication. The production of infectious viral particles by a BGLF2-knockout mutant can be rescued by exogenously expressed BGLF2 but only partially rescued by BGLF2-3KA, which is a mutant with reduced ability to interact with BBLF1 but does not affect its ability to activate the MAPK pathway and the expression of the EBV lytic proteins, suggesting that the interaction of BGLF2 with BBLF1 is important to the efficient production of infectious viral particles during the maturation. The results of this study improve our understanding of how BGLF2 promotes EBV viral production.
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Affiliation(s)
- Chien-Hui Hung
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan, Taiwan.,Division of Infectious Diseases, Chang Gung Memorial Hospital Chiayi Branch, Chiayi, Taiwan
| | - Ya-Fang Chiu
- Department of Microbiology and Immunology, Chang-Gung University, Taoyuan, Taiwan.,Research Center for Emerging Viral Infections, Chang-Gung University, Taoyuan, Taiwan.,Department of Medical Laboratory, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Wen-Hung Wang
- Division of Infectious Disease, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Lee-Wen Chen
- Department of Respiratory Care, Chang-Gung University of Science and Technology, Chiayi, Taiwan
| | - Pey-Jium Chang
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan, Taiwan
| | - Tsung-Yu Huang
- Division of Infectious Diseases, Chang Gung Memorial Hospital Chiayi Branch, Chiayi, Taiwan
| | - Ying-Ju Lin
- Graduate Institute of Chinese Medical Science, China Medical University, Taichung, Taiwan
| | - Wan-Ju Tsai
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan, Taiwan
| | - Chia-Ching Yang
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan, Taiwan
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9
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Sugimoto A, Yamashita Y, Kanda T, Murata T, Tsurumi T. Epstein-Barr virus genome packaging factors accumulate in BMRF1-cores within viral replication compartments. PLoS One 2019; 14:e0222519. [PMID: 31518362 PMCID: PMC6743757 DOI: 10.1371/journal.pone.0222519] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/02/2019] [Indexed: 12/26/2022] Open
Abstract
Productive replication of Epstein-Barr virus (EBV) during the lytic cycle occurs in discrete sites within nuclei, termed replication compartments. We previously proposed that replication compartments consist of two subnuclear domains: "ongoing replication foci" and "BMRF1-cores". Viral genome replication takes place in ongoing replication foci, which are enriched with viral replication proteins, such as BALF5 and BALF2. Amplified DNA and BMRF1 protein accumulate in BMRF1-cores, which are surrounded by ongoing replication foci. We here determined the locations of procapsid and genome-packaging proteins of EBV via three-dimensional (3D) surface reconstruction and correlative fluorescence microscopy-electron microscopy (FM-EM). The results revealed that viral factors required for DNA packaging, such as BGLF1, BVRF1, and BFLF1 proteins, are located in the innermost subdomains of the BMRF1-cores. In contrast, capsid structural proteins, such as BBRF1, BORF1, BDLF1, and BVRF2, were found both outside and inside the BMRF1-cores. Based on these observations, we propose a model in which viral procapsids are assembled outside the BMRF1-cores and subsequently migrate therein, where viral DNA encapsidation occurs. To our knowledge, this is the first report describing capsid assembly sites in relation to EBV replication compartments.
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Affiliation(s)
- Atsuko Sugimoto
- Division of Virology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Japan
- Department of Virology, Nagoya University Graduate School of Medicine, Nagoya University, Showa-ku, Nagoya, Japan
- Department of Virology and Parasitology, Fujita Health University, School of Medicine, Toyoake, Japan
| | - Yoriko Yamashita
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Teru Kanda
- Division of Virology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Japan
- Division of Microbiology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Takayuki Murata
- Division of Virology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Japan
- Department of Virology, Nagoya University Graduate School of Medicine, Nagoya University, Showa-ku, Nagoya, Japan
- Department of Virology and Parasitology, Fujita Health University, School of Medicine, Toyoake, Japan
- * E-mail:
| | - Tatsuya Tsurumi
- Division of Virology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, Japan
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10
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Chen LW, Hung CH, Wang SS, Yen JB, Liu AC, Hung YH, Chang PJ. Expression and regulation of the BKRF2, BKRF3 and BKRF4 genes of Epstein-Barr virus. Virus Res 2018; 256:76-89. [PMID: 30096410 DOI: 10.1016/j.virusres.2018.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/02/2018] [Accepted: 08/04/2018] [Indexed: 12/24/2022]
Abstract
The BKRF2, BKRF3 and BKRF4 genes of Epstein-Barr virus (EBV) are located close together in the viral genome, which encode glycoprotein L, uracil-DNA glycosylase and a tegument protein, respectively. Here, we demonstrate that the BKRF2 gene behaves as a true-late lytic gene, whereas the BKRF3 and BKRF4 genes belong to the early lytic gene family. Our results further reveal that both BKRF3 and BKRF4 promoters are new synergistic targets of Zta and Rta, two EBV latent-to-lytic switch transactivators. Multiple Rta- and Zta-responsive elements within the BKRF3 and BKRF4 promoters were identified and characterized experimentally. Importantly, we show that DNA methylation is absolutely required for activation of the BKRF4 promoter by Zta alone or in combination with Rta. Moreover, we find that sodium butyrate, an inducing agent of EBV reactivation, is capable of activating the BKRF4 promoter through a mechanism independent of Zta and Rta. Overall, our studies highlight the complexity of transcriptional regulation of lytic genes within the BKRF2-BKRF3-BKRF4 gene locus.
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Affiliation(s)
- Lee-Wen Chen
- Department of Respiratory Care, Chang-Gung University of Science and Technology, Chiayi 61363, Taiwan; Department of Pediatric Surgery, Chang-Gung Memorial Hospital, Chiayi 61363, Taiwan
| | - Chien-Hui Hung
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan 33302, Taiwan
| | - Shie-Shan Wang
- Department of Pediatric Surgery, Chang-Gung Memorial Hospital, Chiayi 61363, Taiwan; School of Traditional Chinese Medicine, College of Medicine, Chang-Gung University, Taoyuan 33302, Taiwan
| | - Ju-Bei Yen
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan 33302, Taiwan; Department of Pediatrics, Chang-Gung Memorial Hospital, Chiayi 61363, Taiwan
| | - Ann-Chi Liu
- Department of Respiratory Care, Chang-Gung University of Science and Technology, Chiayi 61363, Taiwan
| | - Ya-Hui Hung
- Department of Respiratory Care, Chang-Gung University of Science and Technology, Chiayi 61363, Taiwan
| | - Pey-Jium Chang
- Graduate Institute of Clinical Medical Sciences, Chang-Gung University, Taoyuan 33302, Taiwan; Department of Nephrology, Chang-Gung Memorial Hospital, Chiayi 61363, Taiwan.
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11
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Characterization of the subcellular localization of Epstein-Barr virus encoded proteins in live cells. Oncotarget 2017; 8:70006-70034. [PMID: 29050259 PMCID: PMC5642534 DOI: 10.18632/oncotarget.19549] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 06/29/2017] [Indexed: 12/27/2022] Open
Abstract
Epstein-Barr virus (EBV) is the pathogenic factor of numerous human tumors, yet certain of its encoded proteins have not been studied. As a first step for functional identification, we presented the construction of a library of expression constructs for most of the EBV encoded proteins and an explicit subcellular localization map of 81 proteins encoded by EBV in mammalian cells. Viral open reading frames were fused with enhanced yellow fluorescent protein (EYFP) tag in eukaryotic expression plasmid then expressed in COS-7 live cells, and protein localizations were observed by fluorescence microscopy. As results, 34.57% (28 proteins) of all proteins showed pan-nuclear or subnuclear localization, 39.51% (32 proteins) exhibitted pan-cytoplasmic or subcytoplasmic localization, and 25.93% (21 proteins) were found in both the nucleus and cytoplasm. Interestingly, most envelope proteins presented pan-cytoplasmic or membranous localization, and most capsid proteins displayed enriched or complete localization in the nucleus, indicating that the subcellular localization of specific proteins are associated with their roles during viral replication. Taken together, the subcellular localization map of EBV proteins in live cells may lay the foundation for further illustrating the functions of EBV-encoded genes in human diseases especially in its relevant tumors.
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12
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Yin Q, Sides M, Parsons CH, Flemington EK, Lasky JA. Arsenic trioxide inhibits EBV reactivation and promotes cell death in EBV-positive lymphoma cells. Virol J 2017. [PMID: 28637474 PMCID: PMC5480106 DOI: 10.1186/s12985-017-0784-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Epstein-Barr Virus (EBV) is associated with hematopoietic malignancies, such as Burkitt’s lymphoma, post-transplantation lymphoproliferative disorder, and diffuse large B-cell lymphoma. The current approach for EBV-associated lymphoma involves chemotherapy to eradicate cancer cells, however, normal cells may be injured and organ dysfunction may occur with currently employed regimens. This research is focused on employing arsenic trioxide (ATO) as EBV-specific cancer therapy takes advantage of the fact the EBV resides within the malignant cells. Methods and results Our research reveals that low ATO inhibits EBV gene expression and genome replication. EBV spontaneous reactivation starts as early as 6 h after re-suspending EBV-positive Mutu cells in RPMI media in the absence of ATO, however this does not occur in Mutu cells cultured with ATO. ATO’s inhibition of EBV spontaneous reactivation is dose dependent. The expression of the EBV immediate early gene Zta and early gene BMRF1 is blocked with low concentrations of ATO (0.5 nM – 2 nM) in EBV latency type I cells and EBV-infected PBMC cells. The combination of ATO and ganciclovir further diminishes EBV gene expression. ATO-mediated reduction of EBV gene expression can be rescued by co-treatment with the proteasome inhibitor MG132, indicating that ATO promotes ubiquitin conjugation and proteasomal degradation of EBV genes. Co-immunoprecipitation assays with antibodies against Zta pulls down more ubiquitin in ATO treated cell lysates. Furthermore, MG132 reverses the inhibitory effect of ATO on anti-IgM-, PMA- and TGF-β-mediated EBV reactivation. Thus, mechanistically ATO’s inhibition of EBV gene expression occurs via the ubiquitin pathway. Moreover, ATO treatment results in increased cell death in EBV-positive cells compared to EBV-negative cells, as demonstrated by both MTT and trypan blue assays. ATO-induced cell death in EBV-positive cells is dose dependent. ATO and ganciclovir in combination further enhances cell death specifically in EBV-positive cells. Conclusion ATO-mediated inhibition of EBV lytic gene expression results in cell death selectively in EBV-positive lymphocytes, suggesting that ATO may potentially serve as a drug to treat EBV-related lymphomas in the clinical setting.
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Affiliation(s)
- Qinyan Yin
- Department of Medicine, Section of Pulmonary Disease, Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA, 70112, USA
| | - Mark Sides
- Department of Medicine, Section of Pulmonary Disease, Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA, 70112, USA.,Department of Internal Medicine, University of Texas Medical Branch, 300 University Blvd, Galveston, TX, 77550, USA
| | - Christopher H Parsons
- Department of Internal Medicine, Louisiana University School of Medicine, 1901 Perdido Street, New Orleans, LA, 70112, USA
| | - Erik K Flemington
- Department of Pathology and Laboratory, Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA, 70112, USA
| | - Joseph A Lasky
- Department of Medicine, Section of Pulmonary Disease, Tulane University School of Medicine, 1430 Tulane Ave, New Orleans, LA, 70112, USA.
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13
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Huang HH, Chen CS, Wang WH, Hsu SW, Tsai HH, Liu ST, Chang LK. TRIM5α Promotes Ubiquitination of Rta from Epstein-Barr Virus to Attenuate Lytic Progression. Front Microbiol 2017; 7:2129. [PMID: 28105027 PMCID: PMC5214253 DOI: 10.3389/fmicb.2016.02129] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/16/2016] [Indexed: 12/04/2022] Open
Abstract
Replication and transcription activator (Rta), a key protein expressed by Epstein–Barr virus (EBV) during the immediate-early stage of the lytic cycle, is responsible for the activation of viral lytic genes. In this study, GST-pulldown and coimmunoprecipitation assays showed that Rta interacts in vitro and in vivo with TRIM5α, a host factor known to be involved in the restriction of retroviral infections. Confocal microscopy results revealed that Rta colocalizes with TRIM5α in the nucleus during lytic progression. The interaction involves 190 amino acids in the N-terminal of Rta and the RING domain in TRIM5α, and it was further found that TRIM5α acts as an E3 ubiquitin ligase to promote Rta ubiquitination. Overexpression of TRIM5α reduced the transactivating capabilities of Rta, while reducing TRIM5α expression enhanced EBV lytic protein expression and DNA replication. Taken together, these results point to a critical role for TRIM5α in attenuating EBV lytic progression through the targeting of Rta for ubiquitination, and suggest that the restrictive capabilities of TRIM5α may go beyond retroviral infections.
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Affiliation(s)
- Hsiang-Hung Huang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University Taipei, Taiwan
| | - Chien-Sin Chen
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University Taipei, Taiwan
| | - Wen-Hung Wang
- Department of Internal Medicine, Kaohsiung Medical University Hospital Kaohsiung, Taiwan
| | - Shih-Wei Hsu
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University Taipei, Taiwan
| | - Hsiao-Han Tsai
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University Taipei, Taiwan
| | - Shih-Tung Liu
- Molecular Genetics Laboratory, Department of Microbiology and Immunology, Chang-Gung University Taoyuan, Taiwan
| | - Li-Kwan Chang
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University Taipei, Taiwan
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14
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Wang L, Tan H, Wu M, Jimenez-Gongora T, Tan L, Lozano-Duran R. Dynamic Virus-Dependent Subnuclear Localization of the Capsid Protein from a Geminivirus. FRONTIERS IN PLANT SCIENCE 2017; 8:2165. [PMID: 29312406 PMCID: PMC5744400 DOI: 10.3389/fpls.2017.02165] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 12/08/2017] [Indexed: 05/13/2023]
Abstract
Viruses are intracellular parasites with a nucleic acid genome and a proteinaceous capsid. Viral capsids are formed of at least one virus-encoded capsid protein (CP), which is often multifunctional, playing additional non-structural roles during the infection cycle. In animal viruses, there are examples of differential localization of CPs associated to the progression of the infection and/or enabled by other viral proteins; these changes in the distribution of CPs may ultimately regulate the involvement of these proteins in different viral functions. In this work, we analyze the subcellular localization of a GFP- or RFP-fused CP from the plant virus Tomato yellow leaf curl virus (TYLCV; Fam. Geminiviridae) in the presence or absence of the virus upon transient expression in the host plants Nicotiana benthamiana and tomato. Our findings show that, in agreement with previous reports, when the CP is expressed alone it localizes mainly in the nucleolus and weakly in the nucleoplasm. Interestingly, the presence of the virus causes the sequential re-localization of the CP outside of the nucleolus and into discrete nuclear foci and, eventually, into an uneven distribution in the nucleoplasm. Expression of the viral replication-associated protein, Rep, is sufficient to exclude the CP from the nucleolus, but the localization of the CP in the characteristic patterns induced by the virus cannot be recapitulated by co-expression with any individual viral protein. Our results demonstrate that the subcellular distribution of the CP is a dynamic process, temporally regulated throughout the progression of the infection. The regulation of the localization of the CP is determined by the presence of other viral components or changes in the cellular environment induced by the virus, and is likely to contribute to the multifunctionality of this protein. Bearing in mind these observations, we suggest that viral proteins should be studied in the context of the infection and considering the temporal dimension in order to comprehensively understand their roles and effects in the interaction between virus and host.
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Affiliation(s)
- Liping Wang
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Huang Tan
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Mengshi Wu
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Tamara Jimenez-Gongora
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
| | - Rosa Lozano-Duran
- Shanghai Center for Plant Stress Biology and Center for Excellence in Molecular Plant Science, Chinese Academy of Sciences, Shanghai, China
- *Correspondence: Rosa Lozano-Duran,
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15
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Changotra H, Turk SM, Artigues A, Thakur N, Gore M, Muggeridge MI, Hutt-Fletcher LM. Epstein-Barr virus glycoprotein gM can interact with the cellular protein p32 and knockdown of p32 impairs virus. Virology 2016; 489:223-32. [PMID: 26773383 DOI: 10.1016/j.virol.2015.12.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/23/2015] [Accepted: 12/29/2015] [Indexed: 02/08/2023]
Abstract
The Epstein-Barr virus glycoprotein complex gMgN has been implicated in assembly and release of fully enveloped virus, although the precise role that it plays has not been elucidated. We report here that the long predicted cytoplasmic tail of gM is not required for complex formation and that it interacts with the cellular protein p32, which has been reported to be involved in nuclear egress of human cytomegalovirus and herpes simplex virus. Although redistribution of p32 and colocalization with gM was not observed in virus infected cells, knockdown of p32 expression by siRNA or lentivirus-delivered shRNA recapitulated the phenotype of a virus lacking expression of gNgM. A proportion of virus released from cells sedimented with characteristics of virus lacking an intact envelope and there was an increase in virus trapped in nuclear condensed chromatin. The observations suggest the possibility that p32 may also be involved in nuclear egress of Epstein-Barr virus.
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Affiliation(s)
- Harish Changotra
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Susan M Turk
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Antonio Artigues
- Department of Biochemistry, University of Kansas Medical Center, Kansas City, KS, USA
| | - Nagendra Thakur
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Mindy Gore
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Martin I Muggeridge
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA
| | - Lindsey M Hutt-Fletcher
- Department of Microbiology and Immunology, Center for Molecular and Tumor Virology and Feist-Weiller Cancer Center, Louisiana State University Health Sciences Center, Shreveport, LA, USA.
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