Modulation of Vimentin, the CD40 Activation Antigan and Burkitt's Lymphoma Antigen (CD77) by the Epstein-Barr Virus Nuclear Antigen EBNA-4

doi:10.1006/viro.1994.1317

Virology

Volume 202, Issue 1, July 1994, Pages 16-24

https://doi.org/10.1006/viro.1994.1317 Get rights and content

Abstract

The growth transformation of human B cells by Epstein-Barr virus (EBV) is controlled by the coordinate expression of 10 latent viral genes. This transforming capacity is believed to be fundamental to the involvement of the virus in human malignancies of B cell origin. EBV-negative Burkitt's lymphoma (dG75) clones stably expressing one of these EBV-coded antigens, EBNA-4, have been established using an episomal-based plasmid. EBNA-4 expression was found to upregulate the cytoskeletal protein vimentin as well as surface expression of the activation antigen CD40. In addition, the presence of EBNA-4 resulted in downregulation of the Burkitt's lymphoma-associated antigen (BLA/CD77). These studies show for the first time that EBNA-4 modulates the expression of several cellular genes implicated in cell-growth transformation.

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Cited by (33)

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders
2003, Critical Reviews in Oncology/Hematology
Citation Excerpt :
Reverse genetics have shown that EBNA3B is dispensible for B-cell growth transformation [107]. On the other hand EBNA3B expression correlates with upregulation of CD40 and downregulation of CD77 in vitro [117]. EBNA3A–C regulate the expression of certain cellular genes and bind to a variety of host proteins including different isoforms of the cellular transcription factor RBP J-κ [118,119], thus modulating the EBNA2-driven upregulation of cellular and viral promoters [120].
Epstein–Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.
Epstein-Barr virus and oncogenesis: From tumors to transforming genes
2001, Perspectives in Medical Virology
Epstein-Barr virus (EBV) is responsible for the pathogenesis of tumors arising in both lymphoid and epithelial tissues. The virus adopts different forms of latent infection in different tumor types reflecting the complex interplay between EBV and the host cell environment. EBNA1, an essential protein for the maintenance of EBV infection has evolved. It evades immunosurveillance by developing a strategy that prevents the protein being processed through the MHC class I pathway. Studies of the function of individual EBV latent genes have highlighted the ability of these proteins to target specific cell signaling pathways. An understanding of the functions of EBV latent proteins is relevant to the role of the virus in transformation and in addition helps to elucidate the mechanisms regulating cell growth, survival, and differentiation. The chapter provides novel approaches to therapy. Adoptive transfer of EBV-specific cytotoxic T lymphocytes (CTLs) has proved useful in the treatment of immunoblastic B cell lymphomas. The possibility of more direct therapeutic intervention targeting the function of essential EBV latent genes, such as EBNA1 and LMP1, is also a possibility. Thus, drugs that prevent the ability of EBNA1 to bind to oriP or of the TRAFs to interact with LMP1 are developed. The gene therapy strategies that exploit the transcriptional regulation of the EBV genome or target the functional effects of EBV latent genes have been described.
Epstein-Barr virus (EBV) nuclear antigen (EBNA)-4 mutation in EBV- associated malignancies in three different populations
1999, American Journal of Pathology
Different ethnic groups with a high human leukocyte antigen (HLA)-A11 prevalence have been shown to experience a high rate of Epstein-Barr virus (EBV) infection, EBV-associated malignancies, and Epstein-Barr nuclear antigen (EBNA)-4 mutations. The epitopes 399-408 and 416-424 of EBNA-4 are major antigenic epitopes that elicit an HLA-A11 cytotoxic T lymphocyte (CTL. response to EBV infection. Mutations selectively involving one or more nucleotide residues in these epitopes affect the antigenicity of EBNA-4, because the mutant EBV strains are not recognized by the HLA-A11-restricted CTLs. To investigate these mutations in common EBV-associated malignancies occurring in different populations, we studied the mutation rate of epitopes 399-408 and 416-424 of EBNA-4 in 25 cases of EBV-associated Hodgkin's disease (HD), nine cases of AIDS-related non-Hodgkin's lymphoma, and 37 cases of EBV-associated gastric carcinoma (GC. from the United States, Brazil, and Japan. We found one or more mutations in these two epitopes in 50% (6/12) of United States HD, 15% (2/13) of Brazilian HD, 50% (6/12) United States GC and 28% (7/25) Japanese GC, and 22% (2/9) of United States AIDS-lymphoma. Similar mutations were found in 30% (3/10) of United States reactive, 0% (0/6) of Brazilian reactive, and 25% (2/8) Japanese reactive tissues. The most frequent amino acid substitutions were virtually identical to those seen in previously reported isolates from EBV-associated nasopharyngeal carcinomas and Burkitt's lymphomas occurring in high prevalence HLA-A11 regions. However, only 2/28 (7%) mutations occurred in HLA-A11-positive patients. Our studies suggest that: 1. EBNA-4 mutations are a common phenomenon in EBV-associated HD, GC, and AIDS-lymphoma; 2) the mutation rate does not vary in these geographic areas and ethnic groups; 3) EBNA-4 mutations in EBV-associated United States and Brazilian HD, United States and Japanese GC, and United States AIDS lymphomas are not related to patients’ HLA-A11 status.
Prolonged phenotypic, functional, and molecular change in group I Burkitt lymphoma cells on short-term exposure to CD40 ligand
1998, Blood
Group I Burkitt lymphoma (BL) cell lines (L3055, Elijah, Louckes, BL2, and BL29) retaining the original biopsy phenotype were found to undergo prolonged phenotypic, functional, and molecular change on short-term exposure to soluble recombinant CD40L trimer. Sensitivity to, extent of, and duration of change appeared to reflect passage number in that the earliest passaged lines, L3055 and BL29, were generally the most susceptible. Culture of group I BL lines with CD40L resulted in significant growth arrest (without apoptosis) that, for L3055 cells, was sustained for 7 to 9 days after 72 hours of exposure. This was accompanied by the formation of large homotypic aggregates together with gross changes in individual cell morphology and a concomitant upregulation of CD54 (ICAM-1). Three of the five group I BL lines exhibited rapid downregulation of the hallmark CD77 surface antigen, which, for L3055 cells, was maintained for at least 12 days after 72 hours of incubation with CD40L. With the exception of BL2, all group I BL lines were induced to express CD40 homodimers on CD40-stimulation, whereas only monomers were detected in unstimulated cells. Experiments using CD40-transfected Rat-1 fibroblasts showed that the ability to signal for dimer formation required Thr²³⁴of CD40. For L3055 and BL29 cells, an initial 72 hours of exposure to CD40L resulted in the maintenance of homodimers for up to 14 and 10 days, respectively. There was a close correlation between the induction and duration of CD40 homodimers and the appearance of Bcl-2. For L3055 cells, which are sensitive to apoptosis-induction on BCR-engagement, exposure to CD40L for 72 hours was found to provide considerable protection from anti-IgM, which was still significant to 20 days. The implications of such sustained effects on relatively short-term exposure of tumor B cells to CD40L are discussed.
© 1998 by The American Society of Hematology.
Epstein-Barr nuclear antigen-3 and -4 interact with RBP-2N, a major isoform of RBP-Jκ in B lymphocytes
1996, Virology
The Epstein–Barr nuclear antigen (EBNA)-3 and EBNA-4 proteins are thought to act as transcriptional transactivators. The yeast two-hybrid system and coimmunoprecipitation were used to demonstrate that EBNA-3 and -4 associate with the DNA-binding protein RBP-2N, an isoform of RBP-Jκ. A comparison between EBNA-3, EBNA-4, and EBNA-6 binding to RBP-2N indicated that EBNA-3 enhanced β-galactosidase activity 4-fold more than EBNA-6 and 30-fold more than EBNA-4. Assay of RBP-2N deletion mutants demonstrated that EBNA-3 binds to regions of RBP-2N which are distinct from those to which EBNA-2 and -6 interact, whereas EBNA-4 binds to the same region of RBP-2N as EBNA-2 and -6 (amino acids 159–331 of RBP-2N). Interaction of both A- and B-type EBNA-3 with RBP-2N was also demonstrated by immunoprecipitation. RT-PCR analysis of a panel of B cell lymphomas and lymphoblastoid cell lines demonstrated that higher levels of RBP-2N were expressed, in comparison to RBP-Jκ, indicating that RBP-2N is a major isoform expressed in B cells. These results suggest that all the EBNA-3 family proteins lead to transcriptional regulation via interaction with RBP-2N.
Induction of pleckstrin by the Epstein-Barr virus nuclear antigen 3 family
1996, Virology
The Epstein–Barr virus (EBV) encoded nuclear antigens, EBNA-3, -4, and -6 (EBNA 3 family) are expressed in latently infected human B-cells and are involved in the transformation of lymphocytes by EBV. Human Burkitt's lymphoma (BL) dG75 cells which stably expressed either the complete EBNA 3 gene family or the vector alone were generated and changes in gene activity in these transfectants were assayed using the differential display of mRNA technique. For the first time, the human gene pleckstrin, which is thought to be involved in signalling and differentiation of hemopoietic cells, was found to be upregulated in the presence of the EBNA 3 protein family, but not in cells expressing the individual EBNA-3, -4, or -6 gene. Pleckstrin was increased up to sevenfold in different cell clones and the bulk culture of EBNA 3 gene family expressing cells as demonstrated by Northern blot, RT-PCR, and immunoblot. In contrast to EBV-negative BL cells, pleckstrin RNA and protein were highly expressed in EBV growth transformed lymphoblastoid cell lines which are thought to play an important role in EBV persistencein vivo.These data suggest that induction of pleckstrin might be important for the EBV-controlled activation of cells and offers a unique biological system for analyzing pleckstrin function.

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Regular ArticleModulation of Vimentin, the CD40 Activation Antigan and Burkitt's Lymphoma Antigen (CD77) by the Epstein-Barr Virus Nuclear Antigen EBNA-4

Abstract

Regular Article
Modulation of Vimentin, the CD40 Activation Antigan and Burkitt's Lymphoma Antigen (CD77) by the Epstein-Barr Virus Nuclear Antigen EBNA-4