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Wyżewski Z, Mielcarska MB, Gregorczyk-Zboroch KP, Myszka A. Virus-Mediated Inhibition of Apoptosis in the Context of EBV-Associated Diseases: Molecular Mechanisms and Therapeutic Perspectives. Int J Mol Sci 2022; 23:ijms23137265. [PMID: 35806271 PMCID: PMC9266970 DOI: 10.3390/ijms23137265] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 12/10/2022] Open
Abstract
Epstein-Barr virus (EBV), the representative of the Herpesviridae family, is a pathogen extensively distributed in the human population. One of its most characteristic features is the capability to establish latent infection in the host. The infected cells serve as a sanctuary for the dormant virus, and therefore their desensitization to apoptotic stimuli is part of the viral strategy for long-term survival. For this reason, EBV encodes a set of anti-apoptotic products. They may increase the viability of infected cells and enhance their resistance to chemotherapy, thereby contributing to the development of EBV-associated diseases, including Burkitt’s lymphoma (BL), Hodgkin’s lymphoma (HL), gastric cancer (GC), nasopharyngeal carcinoma (NPC) and several other malignancies. In this paper, we have described the molecular mechanism of anti-apoptotic actions of a set of EBV proteins. Moreover, we have reviewed the pro-survival role of non-coding viral transcripts: EBV-encoded small RNAs (EBERs) and microRNAs (miRNAs), in EBV-carrying malignant cells. The influence of EBV on the expression, activity and/or intracellular distribution of B-cell lymphoma 2 (Bcl-2) protein family members, has been presented. Finally, we have also discussed therapeutic perspectives of targeting viral anti-apoptotic products or their molecular partners.
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Affiliation(s)
- Zbigniew Wyżewski
- Institute of Biological Sciences, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland;
- Correspondence: ; Tel.: +48-728-208-338
| | - Matylda Barbara Mielcarska
- Institute of Veterinary Medicine, Warsaw University of Life Sciences—SGGW, Nowoursynowska 166, 02-787 Warsaw, Poland; (M.B.M.); (K.P.G.-Z.)
| | | | - Anna Myszka
- Institute of Biological Sciences, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland;
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Tan KE, Ng WL, Marinov GK, Yu KHO, Tan LP, Liau ES, Goh SY, Yeo KS, Yip KY, Lo KW, Khoo ASB, Yap LF, Ea CK, Lim YY. Identification and characterization of a novel Epstein-Barr Virus-encoded circular RNA from LMP-2 Gene. Sci Rep 2021; 11:14392. [PMID: 34257379 PMCID: PMC8277822 DOI: 10.1038/s41598-021-93781-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/30/2021] [Indexed: 11/21/2022] Open
Abstract
Epstein-Barr virus (EBV) has been recently found to generate novel circular RNAs (circRNAs) through backsplicing. However, comprehensive catalogs of EBV circRNAs in other cell lines and their functional characterization are still lacking. In this study, we have identified a list of putative EBV circRNAs in GM12878, an EBV-transformed lymphoblastoid cell line, with a significant majority encoded from the EBV latent genes. A novel EBV circRNA derived from the exon 5 of LMP-2 gene which exhibited highest prevalence, was further validated using RNase R assay and Sanger sequencing. This circRNA, which we term circLMP-2_e5, can be universally detected in a panel of EBV-positive cell lines modelling different latency programs. It ranges from lower expression in nasopharyngeal carcinoma (NPC) cells to higher expression in B cells, and is localized to both the cytoplasm and the nucleus. We provide evidence that circLMP-2_e5 is expressed concomitantly with its cognate linear LMP-2 RNA upon EBV lytic reactivation, and may be produced as a result of exon skipping, with its circularization possibly occurring without the involvement of cis elements in the short flanking introns. Furthermore, we show that circLMP-2_e5 is not involved in regulating cell proliferation, host innate immune response, its linear parental transcripts, or EBV lytic reactivation. Taken together, our study expands the current repertoire of putative EBV circRNAs, broadens our understanding of the biology of EBV circRNAs, and lays the foundation for further investigation of their function in the EBV life cycle and disease development.
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Affiliation(s)
- Ke-En Tan
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Wei Lun Ng
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Georgi K Marinov
- Department of Biology, Indiana University Bloomington, Bloomington, IN, 47405-7005, USA
- Department of Genetics, Stanford University, Stanford, CA, 94305, USA
| | - Ken Hung-On Yu
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Lu Ping Tan
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health Malaysia, 40170, Selangor, Malaysia
| | - Ee Shan Liau
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Sook Yan Goh
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Kok Siong Yeo
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic Cancer Center, Rochester, MN, 55902, USA
| | - Kevin Y Yip
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
- Hong Kong Bioinformatics Centre, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
- Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Kwok-Wai Lo
- Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Alan Soo-Beng Khoo
- Molecular Pathology Unit, Cancer Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health Malaysia, 40170, Selangor, Malaysia
| | - Lee-Fah Yap
- Department of Oral & Craniofacial Sciences, Faculty of Dentistry, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
- Oral Cancer Research and Coordinating Centre, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Chee-Kwee Ea
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390-9148, USA.
| | - Yat-Yuen Lim
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
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Zhu S, Chen J, Xiong Y, Kamara S, Gu M, Tang W, Chen S, Dong H, Xue X, Zheng ZM, Zhang L. Novel EBV LMP-2-affibody and affitoxin in molecular imaging and targeted therapy of nasopharyngeal carcinoma. PLoS Pathog 2020; 16:e1008223. [PMID: 31905218 PMCID: PMC6964910 DOI: 10.1371/journal.ppat.1008223] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/16/2020] [Accepted: 11/18/2019] [Indexed: 12/16/2022] Open
Abstract
Epstein-Barr virus (EBV) infection is closely linked to several human malignancies including endemic Burkitt’s lymphoma, Hodgkin’s lymphoma and nasopharyngeal carcinomas (NPC). Latent membrane protein 2 (LMP-2) of EBV plays a pivotal role in pathogenesis of EBV-related tumors and thus, is a potential target for diagnosis and targeted therapy of EBV LMP-2+ malignant cancers. Affibody molecules are developing as imaging probes and tumor-targeted delivery of small molecules. In this study, four EBV LMP-2-binding affibodies (ZEBV LMP-212, ZEBV LMP-2132, ZEBV LMP-2137, and ZEBV LMP-2142) were identified by screening a phage-displayed LMP-2 peptide library for molecular imaging and targeted therapy in EBV xenograft mice model. ZEBV LMP-2 affibody has high binding affinity for EBV LMP-2 and accumulates in mouse tumor derived from EBV LMP-2+ xenografts for 24 h after intravenous (IV) injection. Subsequent fusion of Pseudomonas exotoxin PE38KDEL to the ZEBV LMP-2 142 affibody led to production of Z142X affitoxin. This fused Z142X affitoxin exhibits high cytotoxicity specific for EBV+ cells in vitro and significant antitumor effect in mice bearing EBV+ tumor xenografts by IV injection. The data provide the proof of principle that EBV LMP-2-speicifc affibody molecules are useful for molecular imaging diagnosis and have potentials for targeted therapy of LMP-2-expressing EBV malignancies. Molecular imaging diagnosis and targeted therapy have been successfully used for several types of tumors, but not yet applied to diagnose or treat EBV-associated NPC. Affibody molecules are small proteins engineered to bind to a large number of target proteins with high affinity, and therefore, can be developed as potential biopharmaceutical drugs for molecular diagnosis and therapeutic applications. In the present study, we screened and characterized EBV LMP-2-specific affibodies and evaluated their usage in molecular imaging of LMP-2 expressing cells and EBV LMP-2 tumor-bearing mice. Subsequently, we engineered and obtained an EBV LMP-2 affitoxin based on EBV LMP-2-binding affibodies and demonstrated its targeted cytotoxicity for EBV+ cell lines in vitro and in vivo. Our data indicate that the EBV LMP-2-specific affibody and its derived affitoxin are useful for diagnosis of LMP-2 expressing cells and targeted therapy of EBV-derived, LMP-2+ malignancies.
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Affiliation(s)
- Shanli Zhu
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Jun Chen
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Yirong Xiong
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Saidu Kamara
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Meiping Gu
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Wanlin Tang
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Shao Chen
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Haiyan Dong
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Xiangyang Xue
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland, United States of America
- * E-mail: (ZMZ); (LZ)
| | - Lifang Zhang
- Institute of Molecular Virology and Immunology, Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang, PR China
- * E-mail: (ZMZ); (LZ)
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Abstract
Latent Epstein–Barr virus (EBV) infection has a substantial role in causing many human disorders. The persistence of these viral genomes in all malignant cells, yet with the expression of limited latent genes, is consistent with the notion that EBV latent genes are important for malignant cell growth. While the EBV-encoded nuclear antigen-1 (EBNA-1) and latent membrane protein-2A (LMP-2A) are critical, the EBNA-leader proteins, EBNA-2, EBNA-3A, EBNA-3C and LMP-1, are individually essential for in vitro transformation of primary B cells to lymphoblastoid cell lines. EBV-encoded RNAs and EBNA-3Bs are dispensable. In this review, the roles of EBV latent genes are summarized.
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Affiliation(s)
- Myung-Soo Kang
- 1] Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Samsung Medical Center, Sungkyunkwan University, Seoul, Korea [2] Samsung Biomedical Research Institute (SBRI), Samsung Medical Center, Sungkyunkwan University, Seoul, Korea
| | - Elliott Kieff
- Department of Medicine, Brigham and Women's Hospital, Program in Virology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
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Abstract
LMP2A is an EBV-encoded protein with three domains: (a) an N-terminal cytoplasmic domain, which has PY motifs that bind to WW domain-containing E3 ubiquitin ligases and an ITAM that binds to SH2 domain-containing proteins, (b) a transmembrane domain with 12 transmembrane segments that localizes LMP2A in cellular membranes, and (c) a 27-amino acid C-terminal domain which mediates homodimerization and heterodimerization of LMP2 protein isoforms. The most prominent two isoforms of the protein are LMP2A and LMP2B. The LMP2B isoform lacks the 19-amino acid N-terminal domain found in LMP2A, which modulates cellular signaling resulting in a baseline activation of B cells and degradation of cellular kinases leading to the downregulation of normal B cell signaling pathways. These two seemingly contradictory processes allow EBV to establish and maintain latency. LMP2 is expressed in many EBV-associated malignancies. While its antigenic properties may be useful in developing LMP2-specific immunity, the LMP2A N-terminal motifs also provide a basis to target LMP2A-modulated cellular kinases for the development of treatment strategies.
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Vincent-Bugnas S, Vitale S, Mouline CC, Khaali W, Charbit Y, Mahler P, Prêcheur I, Hofman P, Maryanski JL, Doglio A. EBV infection is common in gingival epithelial cells of the periodontium and worsens during chronic periodontitis. PLoS One 2013; 8:e80336. [PMID: 24367478 PMCID: PMC3868609 DOI: 10.1371/journal.pone.0080336] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 10/01/2013] [Indexed: 12/15/2022] Open
Abstract
An amplifying role for oral epithelial cells (ECs) in Epstein-Barr Virus (EBV) infection has been postulated to explain oral viral shedding. However, while lytic or latent EBV infections of oro/nasopharyngeal ECs are commonly detected under pathological conditions, detection of EBV-infected ECs in healthy conditions is very rare. In this study, a simple non-surgical tissue sampling procedure was used to investigate EBV infection in the periodontal epithelium that surrounds and attaches teeth to the gingiva. Surprisingly, we observed that the gingival ECs of the periodontium (pECs) are commonly infected with EBV and may serve as an important oral reservoir of latently EBV-infected cells. We also found that the basal level of epithelial EBV-infection is significantly increased in chronic periodontitis, a common inflammatory disease that undermines the integrity of tooth-supporting tissues. Moreover, the level of EBV infection was found to correlate with disease severity. In inflamed tissues, EBV-infected pECs appear to be prone to apoptosis and to produce larger amounts of CCL20, a pivotal inflammatory chemokine that controls tissue infiltration by immune cells. Our discovery that the periodontal epithelium is a major site of latent EBV infection sheds a new light on EBV persistence in healthy carriers and on the role of this ubiquitous virus in periodontitis. Moreover, the identification of this easily accessible site of latent infection may encourage new approaches to investigate and monitor other EBV-associated disorders.
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Affiliation(s)
- Séverine Vincent-Bugnas
- Université Nice-Sophia Antipolis, UFR Médecine, ImCelVir URE004, Nice, France
- Université Nice-Sophia Antipolis, UFR Odontologie, LSBV URE001, Nice, France
- Centre Hospitalier Universitaire de Nice, Pôle Odontologie, Hôpital Saint Roch, Nice, France
- Centre Hospitalier Universitaire de Nice, Unité de Thérapie Cellulaire et Génique, Nice, France
| | - Sébastien Vitale
- Centre Hospitalier Universitaire de Nice, Cancéropole PACA, Laboratoire de Pathologie Clinique et Expérimentale, Biobanque IRCAN, Inserm U1081, Nice, France
| | - Caroline C. Mouline
- Centre Hospitalier Universitaire de Nice, Unité de Thérapie Cellulaire et Génique, Nice, France
| | - Wafa Khaali
- Université Nice-Sophia Antipolis, UFR Médecine, ImCelVir URE004, Nice, France
- Centre Hospitalier Universitaire de Nice, Unité de Thérapie Cellulaire et Génique, Nice, France
| | - Yves Charbit
- Université Nice-Sophia Antipolis, UFR Odontologie, LSBV URE001, Nice, France
- Centre Hospitalier Universitaire de Nice, Pôle Odontologie, Hôpital Saint Roch, Nice, France
| | - Patrick Mahler
- Centre Hospitalier Universitaire de Nice, Pôle Odontologie, Hôpital Saint Roch, Nice, France
| | - Isabelle Prêcheur
- Université Nice-Sophia Antipolis, UFR Odontologie, LSBV URE001, Nice, France
- Centre Hospitalier Universitaire de Nice, Pôle Odontologie, Hôpital Saint Roch, Nice, France
| | - Paul Hofman
- Centre Hospitalier Universitaire de Nice, Cancéropole PACA, Laboratoire de Pathologie Clinique et Expérimentale, Biobanque IRCAN, Inserm U1081, Nice, France
| | - Janet L. Maryanski
- Université Nice-Sophia Antipolis, UFR Médecine, ImCelVir URE004, Nice, France
- Centre Hospitalier Universitaire de Nice, Unité de Thérapie Cellulaire et Génique, Nice, France
- INSERM, UMR 576, F-06202 Nice, France
| | - Alain Doglio
- Université Nice-Sophia Antipolis, UFR Médecine, ImCelVir URE004, Nice, France
- Centre Hospitalier Universitaire de Nice, Unité de Thérapie Cellulaire et Génique, Nice, France
- * E-mail:
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Dawson CW, Port RJ, Young LS. The role of the EBV-encoded latent membrane proteins LMP1 and LMP2 in the pathogenesis of nasopharyngeal carcinoma (NPC). Semin Cancer Biol 2012; 22:144-53. [PMID: 22249143 DOI: 10.1016/j.semcancer.2012.01.004] [Citation(s) in RCA: 221] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 01/02/2012] [Accepted: 01/03/2012] [Indexed: 02/08/2023]
Abstract
Although frequently expressed in EBV-positive malignancies, the contribution of the oncogenic latent membrane proteins, LMP1 and LMP2, to the pathogenesis of nasopharyngeal carcinoma (NPC) is not fully defined. As a key effector in EBV-driven B cell transformation and an established "transforming" gene, LMP1 displays oncogenic properties in rodent fibroblasts and induces profound morphological and phenotypic effects in epithelial cells. LMP1 functions as a viral mimic of the TNFR family member, CD40, engaging a number of signalling pathways that induce morphological and phenotypic alterations in epithelial cells. Although LMP2A plays an essential role in maintaining viral latency in EBV infected B cells, its role in epithelial cells is less clear. Unlike LMP1, LMP2A does not display "classical" transforming functions in rodent fibroblasts but its ability to engage a number of potentially oncogenic cell signalling pathways suggests that LMP2A can also participate in EBV-induced epithelial cell growth transformation. Here we review the effects of LMP1 and LMP2 on various aspects of epithelial cell behaviour highlighting key aspects that may contribute to the pathogenesis of NPC.
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Affiliation(s)
- Christopher W Dawson
- Birmingham Cancer Research UK Cancer Centre, School of Cancer Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.
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Role of latent membrane protein 2 isoforms in Epstein-Barr virus latency. Trends Microbiol 2008; 16:520-7. [PMID: 18835714 DOI: 10.1016/j.tim.2008.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 08/27/2008] [Accepted: 08/28/2008] [Indexed: 12/12/2022]
Abstract
The oncogenic Epstein-Barr virus (EBV) infects the majority of the human population without doing harm and establishes a latent infection in the memory B-cell compartment. To accomplish this, EBV hijacks B-cell differentiation pathways and uses its own viral genes to interfere with B-cell signalling to achieve life-long persistence. EBV latent membrane protein 2A (LMP2A) provides a surrogate B-cell receptor signal essential for cell survival and is believed to have a crucial role in the maintenance of latency by blocking B-cell activation which would otherwise lead to lytic EBV infection. These two functions demand tight control of LMP2A activity and expression levels. Based on recent insights in the function of LMP2B, an isoform of LMP2A, we propose a model for how LMP2B modulates the activity of LMP2A contributing to maintenance of EBV latency.
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Latent membrane protein 2B regulates susceptibility to induction of lytic Epstein-Barr virus infection. J Virol 2007; 82:1739-47. [PMID: 18057232 DOI: 10.1128/jvi.01723-07] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The B-lymphotropic Epstein-Barr virus (EBV) encodes two isoforms of latent membrane protein 2 (LMP2), LMP2A and LMP2B, which are expressed during latency in B cells. The function of LMP2B is largely unknown, whereas LMP2A blocks B-cell receptor (BCR) signaling transduction and induction of lytic EBV infection, thereby promoting B-cell survival. Transfection experiments on LMP2B in EBV-negative B cells and the silencing of LMP2B in EBV-harboring Burkitt's lymphoma-derived Akata cells suggest that LMP2B interferes with the function of LMP2A, but the role of LMP2B in the presence of functional EBV has not been established. Here, LMP2B, LMP2A, or both were overexpressed in EBV-harboring Akata cells to study the function of LMP2B. The overexpression of LMP2B increased the magnitude of EBV switching from its latent to its lytic form upon BCR cross-linking, as indicated by a more-enhanced upregulation and expression of EBV lytic genes and significantly increased production of transforming EBV compared to Akata vector control cells or LMP2A-overexpressing cells. Moreover, LMP2B lowered the degree of BCR cross-linking required to induce lytic EBV infection. Finally, LMP2B colocalized with LMP2A as demonstrated by immunoprecipitation and immunofluorescence and restored calcium mobilization upon BCR cross-linking, a signaling process inhibited by LMP2A. Thus, our findings suggest that LMP2B negatively regulates the function of LMP2A in preventing the switch from latent to lytic EBV replication.
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