scholarly journals Epstein-Barr virus nuclear antigen EBNA-LP is essential for transforming naive B cells, and facilitates recruitment of transcription factors to the viral genome

2017 ◽  
Author(s):  
Agnieszka Szymula ◽  
Richard D. Palermo ◽  
Ian J. Groves ◽  
Mohammed Ba abdullah ◽  
Beth S. Holder ◽  
...  
Keyword(s):  
B Cells ◽  
Viral Genome ◽  
Epstein Barr Virus ◽  
Gene Activation ◽  
Nuclear Antigen ◽  
Virus Protein ◽  
Barr Virus ◽  
Ebv Infection ◽  
Epstein Barr ◽  
Host Genes

AbstractThe Epstein-Barr virus (EBV) nuclear antigen leader protein (EBNA-LP) is the first viral latency-associated protein produced after EBV infection of resting B cells. Its role in B cell transformation is poorly defined, but it is reported to enhance gene activation by the EBV protein EBNA2 in vitro.We generated two sets of EBNA-LP knockout (LPKO) EBVs containing a STOP codon within each repeat unit of IR1. Intronic mutations in the first of these knockouts suggested a role for the EBV sisRNAs in transformation. LPKOs with intact introns established lymphoblastoid cell lines (LCLs) from adult B cells at reduced efficiency, but umbilical cord B cells, and naive (IgD+, CD27-) adult B cells consistently died approximately two weeks after infection with LPKO, failing to establish LCLs.Quantitative PCR analysis of virus gene expression after infection identified both an altered ratio of the EBNA genes, and a dramatic reduction in transcript levels of both EBNA2-regulated virus genes (LMP1 and LMP2) and the EBNA2-independent EBER genes, particularly in the first 1-2 weeks. By 30 days post infection, these levels had equalised. In contrast, EBNA2-regulated host genes were induced efficiently by LPKO viruses. Chromatin immunoprecipitation revealed that recruitment of EBNA2 and the host factors EBF1 and RBPJ to all latency promoters tested was severely delayed, whereas these same factors were recruited efficiently to several host genes, some of which exhibited increased EBNA2 recruitment.We conclude that EBNA-LP does not simply co-operate with EBNA2 in activating gene transcription, but rather facilitates the recruitment of several transcription factors to the viral genome, to enable transcription of virus latency genes. Additionally, our findings suggest that different properties of EBV may have differing importance in transforming different B cell subsets.Author summaryEpstein-Barr virus (EBV) infects almost everyone. Once infected, people harbor the virus for life, shedding it in saliva. Infection of children is asymptomatic, but a first infection during adolescence or adulthood can cause glandular fever (mono). EBV is also implicated in several different cancers. EBV infection of B cells (the immune cell that produces antibodies) can drive them to replicate almost indefinitely (‘transformation’), generating cell lines. We have investigated the role of a virus protein – EBNA-LP – which is thought to support gene activation by the essential virus protein EBNA2.We have made an EBV in which the EBNA-LP gene has been disrupted. This virus (LPKO) shows several properties. 1. It is reduced in its ability to transform adult cells, while immature B cells (more frequent in the young) die two weeks after LPKO infection. 2. Some virus genes fail to turn on immediately after LPKO infection. 3. Binding of EBNA2 to these genes is delayed, as is binding of some cellular factors. 4. EBNA-LP does not affect EBNA2-targeted cellular genes in the same way.This shows that EBNA-LP is more important in immature cells, and that it regulates virus genes – but not host genes – more widely than simply through EBNA2.

scholarly journals Epstein-Barr virus nuclear antigen 3C (EBNA3C) interacts with the metabolism sensing C-terminal binding protein (CtBP) repressor to upregulate host genes

2021 ◽  
Vol 17 (3) ◽  
pp. e1009419
Author(s):  
Makoto Ohashi ◽  
Mitchell Hayes ◽  
Kyle McChesney ◽  
Eric Johannsen
Keyword(s):  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Lymphoblastoid Cell Lines ◽  
Exon 2 ◽  
Epithelial Cancers ◽  
Barr Virus ◽  
Ebv Infection ◽  
Epstein Barr ◽  
Host Genes

Epstein-Barr virus (EBV) infection is associated with the development of specific types of lymphoma and some epithelial cancers. EBV infection of resting B-lymphocytes in vitro drives them to proliferate as lymphoblastoid cell lines (LCLs) and serves as a model for studying EBV lymphomagenesis. EBV nuclear antigen 3C (EBNA3C) is one of the genes required for LCL growth and previous work has suggested that suppression of the CDKN2A encoded tumor suppressor p16INK4A and possibly p14ARF is central to EBNA3C’s role in this growth transformation. To directly assess whether loss of p16 and/or p14 was sufficient to explain EBNA3C growth effects, we used CRISPR/Cas9 to disrupt specific CDKN2A exons in EBV transformed LCLs. Disruption of p16 specific exon 1α and the p16/p14 shared exon 2 were each sufficient to restore growth in the absence of EBNA3C. Using EBNA3C conditional LCLs knocked out for either exon 1α or 2, we identified EBNA3C induced and repressed genes. By trans-complementing with EBNA3C mutants, we determined specific genes that require EBNA3C interaction with RBPJ or CtBP for their regulation. Unexpectedly, interaction with the CtBP repressor was required not only for repression, but also for EBNA3C induction of many host genes. Contrary to previously proposed models, we found that EBNA3C does not recruit CtBP to the promoters of these genes. Instead, our results suggest that CtBP is bound to these promoters in the absence of EBNA3C and that EBNA3C interaction with CtBP interferes with the repressive function of CtBP, leading to EBNA3C mediated upregulation.

scholarly journals Identification of Epstein-Barr Virus (EBV) Nuclear Antigen 2 (EBNA2) Target Proteins by Proteome Analysis: Activation of EBNA2 in Conditionally Immortalized B Cells Reflects Early Events after Infection of Primary B Cells by EBV

2004 ◽  
Vol 78 (8) ◽  
pp. 3941-3952 ◽  
Author(s):  
Martin Schlee ◽  
Tanja Krug ◽  
Olivier Gires ◽  
Reinhard Zeidler ◽  
Wolfgang Hammerschmidt ◽  
...  
Keyword(s):  
B Cells ◽  
Protein Expression ◽  
B Cell ◽  
Cell Line ◽  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Target Proteins ◽  
Barr Virus ◽  
Ebv Infection ◽  
Epstein Barr

ABSTRACT The Epstein-Barr virus (EBV) is a ubiquitous B-lymphotropic herpesvirus associated with several malignant tumors, e.g., Burkitt's lymphoma and Hodgkin's disease, and is able to efficiently immortalize primary B lymphocytes in vitro. The growth program of infected B cells is initiated and maintained by the viral transcription factor EBV nuclear antigen 2 (EBNA2), which regulates viral and cellular genes, including the proto-oncogene c-myc. In our study, patterns of protein expression in B cells with and without EBNA2 were analyzed by two-dimensional polyacrylamide gel electrophoresis and mass spectrometry. For this purpose, we used a conditional immortalization system for EBV, a B cell line (EREB2-5) that expresses an estrogen receptor-EBNA2 fusion protein. In order to discriminate downstream targets of c-Myc from c-Myc-independent EBNA2 targets, we used an EREB2-5-derived cell line, P493-6, in which c-Myc is expressed under the control of a tetracycline-regulated promoter. Of 20 identified EBNA2 target proteins, 11 were c-Myc dependent and therefore most probably associated with proliferation, and one of these proteins was a posttranslationally modified protein, i.e., hypusinylated eIF5a. Finally, to estimate the relevance of EBNA2 targets during early EBV infection, we analyzed the proteomes of primary B cells before and after infection with EBV. The protein expression pattern induced upon EBV infection was similar to that following EBNA2 activation. These findings underscore the value of EREB2-5 cells as an appropriate model system for the analysis of early events in the process of EBV-mediated B-cell immortalization.

scholarly journals Correction: Epstein-Barr virus nuclear antigen EBNA-LP is essential for transforming naïve B cells, and facilitates recruitment of transcription factors to the viral genome

2019 ◽  
Vol 15 (2) ◽  
pp. e1007403
Author(s):  
Agnieszka Szymula ◽  
Richard D. Palermo ◽  
Amr Bayoumy ◽  
Ian J. Groves ◽  
Mohammed Ba abdullah ◽  
...  
Keyword(s):  
Transcription Factors ◽  
B Cells ◽  
Viral Genome ◽  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals Epstein-Barr virus nuclear antigen EBNA-LP is essential for transforming naïve B cells, and facilitates recruitment of transcription factors to the viral genome

2018 ◽  
Vol 14 (2) ◽  
pp. e1006890 ◽  
Author(s):  
Agnieszka Szymula ◽  
Richard D. Palermo ◽  
Amr Bayoumy ◽  
Ian J. Groves ◽  
Mohammed Ba abdullah ◽  
...  
Keyword(s):  
Transcription Factors ◽  
B Cells ◽  
Viral Genome ◽  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals Epstein-Barr Virus Induces Adhesion Receptor CD226 (DNAM-1) Expression during Primary B-Cell Transformation into Lymphoblastoid Cell Lines

mSphere ◽  
2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Lisa Grossman ◽  
Chris Chang ◽  
Joanne Dai ◽  
Pavel A. Nikitin ◽  
Dereje D. Jima ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Human Herpesvirus ◽  
Barr Virus ◽  
Ebv Infection ◽  
Cellular Aggregation ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) is a common human herpesvirus that establishes latency in B cells. While EBV infection is asymptomatic for most individuals, immune-suppressed individuals are at significantly higher risk of a form of EBV latent infection in which infected B cells are reactivated, grow unchecked, and generate lymphomas. This form of latency is modeled in the laboratory by infecting B cells from the blood of normal human donors in vitro. In this model, we identified a protein called CD226 that is induced by EBV but is not normally expressed on B cells. Rather, it is known to play a role in aggregation and survival signaling of non-B cells in the immune system. Cultures of EBV-infected cells adhere to one another in “clumps,” and while the proteins that are responsible for this cellular aggregation are not fully understood, we hypothesized that this form of cellular aggregation may provide a survival advantage. In this article, we characterize the mechanism by which EBV induces this protein and its expression on lymphoma tissue and cell lines and characterize EBV-infected cell lines in which CD226 has been knocked out. Epstein-Barr virus (EBV), an oncogenic herpesvirus, infects and transforms primary B cells into immortal lymphoblastoid cell lines (LCLs), providing a model for EBV-mediated tumorigenesis. EBV transformation stimulates robust homotypic aggregation, indicating that EBV induces molecules that mediate cell-cell adhesion. We report that EBV potently induced expression of the adhesion molecule CD226, which is not normally expressed on B cells. We found that early after infection of primary B cells, EBV promoted an increase in CD226 mRNA and protein expression. CD226 levels increased further from early proliferating EBV-positive B cells to LCLs. We found that CD226 expression on B cells was independent of B-cell activation as CpG DNA failed to induce CD226 to the extent of EBV infection. CD226 expression was high in EBV-infected B cells expressing the latency III growth program, but low in EBV-negative and EBV latency I-infected B-lymphoma cell lines. We validated this correlation by demonstrating that the latency III characteristic EBV NF-κB activator, latent membrane protein 1 (LMP1), was sufficient for CD226 upregulation and that CD226 was more highly expressed in lymphomas with increased NF-κB activity. Finally, we found that CD226 was not important for LCL steady-state growth, survival in response to apoptotic stress, homotypic aggregation, or adhesion to activated endothelial cells. These findings collectively suggest that EBV induces expression of a cell adhesion molecule on primary B cells that may play a role in the tumor microenvironment of EBV-associated B-cell malignancies or facilitate adhesion in the establishment of latency in vivo. IMPORTANCE Epstein-Barr virus (EBV) is a common human herpesvirus that establishes latency in B cells. While EBV infection is asymptomatic for most individuals, immune-suppressed individuals are at significantly higher risk of a form of EBV latent infection in which infected B cells are reactivated, grow unchecked, and generate lymphomas. This form of latency is modeled in the laboratory by infecting B cells from the blood of normal human donors in vitro. In this model, we identified a protein called CD226 that is induced by EBV but is not normally expressed on B cells. Rather, it is known to play a role in aggregation and survival signaling of non-B cells in the immune system. Cultures of EBV-infected cells adhere to one another in “clumps,” and while the proteins that are responsible for this cellular aggregation are not fully understood, we hypothesized that this form of cellular aggregation may provide a survival advantage. In this article, we characterize the mechanism by which EBV induces this protein and its expression on lymphoma tissue and cell lines and characterize EBV-infected cell lines in which CD226 has been knocked out.

scholarly journals Selective Induction of Th2-Attracting Chemokines CCL17 and CCL22 in Human B Cells by Latent Membrane Protein 1 of Epstein-Barr Virus

2004 ◽  
Vol 78 (4) ◽  
pp. 1665-1674 ◽  
Author(s):  
Takashi Nakayama ◽  
Kunio Hieshima ◽  
Daisuke Nagakubo ◽  
Emiko Sato ◽  
Masahiro Nakayama ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Regulatory T Cells ◽  
Epstein Barr Virus ◽  
Cytotoxic T Cells ◽  
Th2 Cells ◽  
Th1 Cells ◽  
Barr Virus ◽  
Ebv Infection ◽  
Epstein Barr

ABSTRACT Chemokines are likely to play important roles in the pathophysiology of diseases associated with Epstein-Barr virus (EBV). Here, we have analyzed the repertoire of chemokines expressed by EBV-infected B cells. EBV infection of B cells induced expression of TARC/CCL17 and MDC/CCL22, which are known to attract Th2 cells and regulatory T cells via CCR4, and also upregulated constitutive expression of MIP-1α/CCL3, MIP-1β/CCL4, and RANTES/CCL5, which are known to attract Th1 cells and cytotoxic T cells via CCR5. Accordingly, EBV-immortalized B cells secreted these chemokines, especially CCL3, CCL4, and CCL22, in large quantities. EBV infection or stable expression of LMP1 also induced CCL17 and CCL22 in a B-cell line, BJAB. The inhibitors of the TRAF/NF-κB pathway (BAY11-7082) and the p38/ATF2 pathway (SB202190) selectively suppressed the expression of CCL17 and CCL22 in EBV-immortalized B cells and BJAB-LMP1. Consistently, transient-transfection assays using CCL22 promoter-reporter constructs demonstrated that two NF-κB sites and a single AP-1 site were involved in the activation of the CCL22 promoter by LMP1. Finally, serum CCL22 levels were significantly elevated in infectious mononucleosis. Collectively, LMP1 induces CCL17 and CCL22 in EBV-infected B cells via activation of NF-κB and probably ATF2. Production of CCL17 and CCL22, which attract Th2 and regulatory T cells, may help EBV-infected B cells evade immune surveillance by Th1 cells. However, the concomitant production of CCL3, CCL4, and CCL5 by EBV-infected B cells may eventually attract Th1 cells and cytotoxic T cells, leading to elimination of EBV-infected B cells at latency III and to selection of those with limited expression of latent genes.

scholarly journals Chromosomal rearrangements after ex vivo Epstein–Barr virus (EBV) infection of human B cells

Oncogene ◽  
2009 ◽  
Vol 29 (4) ◽  
pp. 503-515 ◽  
Author(s):  
S Lacoste ◽  
E Wiechec ◽  
A G dos Santos Silva ◽  
A Guffei ◽  
G Williams ◽  
...  
Keyword(s):  
B Cells ◽  
Epstein Barr Virus ◽  
Ex Vivo ◽  
Chromosomal Rearrangements ◽  
Barr Virus ◽  
Ebv Infection ◽  
Human B Cells ◽  
Epstein Barr

scholarly journals The Epstein-Barr virus (EBV) nuclear antigen 1 BamHI F promoter is activated on entry of EBV-transformed B cells into the lytic cycle.

1992 ◽  
Vol 66 (12) ◽  
pp. 7461-7468 ◽  
Author(s):  
A L Lear ◽  
M Rowe ◽  
M G Kurilla ◽  
S Lee ◽  
S Henderson ◽  
...  
Keyword(s):  
B Cells ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Epstein Barr

Encephalitis in Infectious Mononucleosis: Diagnostic Considerations

PEDIATRICS ◽  
1976 ◽  
Vol 58 (6) ◽  
pp. 877-880
Author(s):  
Beverly J. Lange ◽  
Peter H. Berman ◽  
Joseph Bender ◽  
Werner Henle ◽  
John F. Hewetson
Keyword(s):  
Infectious Mononucleosis ◽  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Diffuse Component ◽  
Early Antigen ◽  
Barr Virus ◽  
Ebv Infection ◽  
Antibody Titers ◽  
Epstein Barr ◽  
Etiologic Diagnosis

Four atypical cases of presumed infectious mononucleosis (IM) encephalitis are presented. To establish an etiologic diagnosis, Paul-Bunnell-Davidsohn heterophil titers (PBD), antibody titers to the antigens of the Epstein-Barr virus (EBV), and oropharyngeal excretion of EBV were determined. Criteria for a primary EBV infection are (1) an antiviral capsid antigen titer of 1:160 or greater, (2) the presence of antibody to the diffuse component of the early antigen, (3) absence of antibody to the nuclear antigen, and (4) excretion of the virus from the oropharynx. Three of the four cases met these criteria; of the three, one did not have a positive heterophil titer. The fourth case turned out not to be IM; there was a positive PBD heterophil, but there was no evidence of primary EBV infection. Although the PBD heterophil is usually a reliable test to diagnosis IM, it is not always present in children, and it is sometimes nonspecifically elevated. Some EBV titers can be nonspecifically elevated as well; however, the above criteria are diagnostic of primary EBV infection.

Sign in / Sign up

Export Citation Format

Share Document