scholarly journals Epstein–Barr virus nuclear antigen 3A protein regulates CDKN2B transcription via interaction with MIZ-1

2014 ◽  
Vol 42 (15) ◽  
pp. 9700-9716 ◽  
Author(s):  
Quentin Bazot ◽  
Thibaut Deschamps ◽  
Lionel Tafforeau ◽  
Maha Siouda ◽  
Pascal Leblanc ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Target Genes ◽  
Zinc Finger Protein ◽  
Transformation Process ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Trimeric Complex ◽  
Growth Inhibitory ◽  
Infected Cells ◽  
Epstein Barr

AbstractThe Epstein–Barr virus (EBV) nuclear antigen 3 family of protein is critical for the EBV-induced primary B-cell growth transformation process. Using a yeast two-hybrid screen we identified 22 novel cellular partners of the EBNA3s. Most importantly, among the newly identified partners, five are known to play direct and important roles in transcriptional regulation. Of these, the Myc-interacting zinc finger protein-1 (MIZ-1) is a transcription factor initially characterized as a binding partner of MYC. MIZ-1 activates the transcription of a number of target genes including the cell cycle inhibitor CDKN2B. Focusing on the EBNA3A/MIZ-1 interaction we demonstrate that binding occurs in EBV-infected cells expressing both proteins at endogenous physiological levels and that in the presence of EBNA3A, a significant fraction of MIZ-1 translocates from the cytoplasm to the nucleus. Moreover, we show that a trimeric complex composed of a MIZ-1 recognition DNA element, MIZ-1 and EBNA3A can be formed, and that interaction of MIZ-1 with nucleophosmin (NPM), one of its coactivator, is prevented by EBNA3A. Finally, we show that, in the presence of EBNA3A, expression of the MIZ-1 target gene, CDKN2B, is downregulated and repressive H3K27 marks are established on its promoter region suggesting that EBNA3A directly counteracts the growth inhibitory action of MIZ-1.

scholarly journals Cellular Target Genes of Epstein-Barr Virus Nuclear Antigen 2

2006 ◽  
Vol 80 (19) ◽  
pp. 9761-9771 ◽  
Author(s):  
Sabine Maier ◽  
Gabriele Staffler ◽  
Andrea Hartmann ◽  
Julia Höck ◽  
Karen Henning ◽  
...  
Keyword(s):  
Cell Cycle ◽  
B Cell ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Target Genes ◽  
Transformation Process ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Cellular Target ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) nuclear antigen 2 (EBNA-2) is a key determinant in the EBV-driven B-cell growth transformation process. By activating an array of viral and cellular target genes, EBNA-2 initiates a cascade of events which ultimately cause cell cycle entry and the proliferation of the infected B cell. In order to identify cellular target genes that respond to EBNA-2 in the absence of other viral factors, we have performed a comprehensive search for EBNA-2 target genes in two EBV-negative B-cell lines. This screen identified 311 EBNA-2-induced and 239 EBNA-2-repressed genes that were significantly regulated in either one or both cell lines. The activation of most of these genes had not previously been attributed to EBNA-2 function and will be relevant for the identification of EBNA-2-specific contributions to EBV-associated malignancies. The diverse spectrum of EBNA-2 target genes described in this study reflects the broad spectrum of EBNA-2 functions involved in virus-host interactions, including cell signaling molecules, adapters, genes involved in cell cycle regulation, and chemokines.

scholarly journals Plasmacytic differentiation of circulating Epstein-Barr virus-infected B lymphocytes during acute infectious mononucleosis.

1981 ◽  
Vol 153 (2) ◽  
pp. 235-244 ◽  
Author(s):  
J E Robinson ◽  
D Smith ◽  
J Niederman
Keyword(s):  
Infectious Mononucleosis ◽  
Epstein Barr Virus ◽  
Plasma Cells ◽  
Phase 1 ◽  
Acute Disease ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Infected Cells ◽  
Epstein Barr ◽  
Acute Infectious Mononucleosis

During the acute phase (1 wk of symptoms or less) of infectious mononucleosis (IM), 70--80% of circulating Epstein-Barr virus nuclear antigen (EBNA)-positive cells have differentiated toward plasma cells. Thus the characteristics of the infected cells in the majority of IM patients during early disease are indistinguishable from EBNA-positive tumor cells of a previously reported child who developed lymphoma during IM. IgA and IgG were the most frequent and IgM the least frequent immunoglobulin isotypes detected in EBNA-positive cells. In acute disease EBNA was present in 5.5--20% of T cell-depleted blood lymphocytes but in the 2nd or 3rd wk of illness the number of EBNA-positive cells sharply decreased to 0.4--1.4%. At the same time the fraction of antigen-positive cells containing cytoplasmic immunoglobulins also diminished, suggesting either that differentiation of infected cells was altered during the disease or that nondifferentiated antigen-positive cells had a survival advantage. Both the high proportion of plasmacytic EBNA-positive cells seen during acute disease and the apparent loss of differentiation by these cells later in disease may be regulated by host immunologic factors. Immunoglobulin-producing EBNA-positive cells may be the source of heterophile antibodies and other seemingly inappropriate antibodies usually found in serum during IM; however, increased numbers of noninfected plasma cells were present in some patients and may also be a potential source of these unusual antibodies.

scholarly journals Epstein–Barr virus nuclear antigen (EBNA) 3A induces the expression of and interacts with a subset of chaperones and co-chaperones

2008 ◽  
Vol 89 (4) ◽  
pp. 866-877 ◽  
Author(s):  
Paul Young ◽  
Emma Anderton ◽  
Kostas Paschos ◽  
Rob White ◽  
Martin J. Allday
Keyword(s):  
Epstein Barr Virus ◽  
Expression System ◽  
Nuclear Antigen ◽  
Human Diploid Fibroblasts ◽  
Barr Virus ◽  
Cellular Genes ◽  
Infected Cells ◽  
Epstein Barr ◽  
Chaperone Complex

Viral nuclear oncoproteins EBNA3A and EBNA3C are essential for the efficient immortalization of B cells by Epstein–Barr virus (EBV) in vitro and it is assumed that they play an essential role in viral persistence in the human host. In order to identify cellular genes regulated by EBNA3A expression, cDNA encoding EBNA3A was incorporated into a recombinant adenoviral vector. Microarray analysis of human diploid fibroblasts infected with either adenovirus EBNA3A or an empty control adenovirus consistently showed an EBNA3A-specific induction of mRNA corresponding to the chaperones Hsp70 and Hsp70B/B′ and co-chaperones Bag3 and DNAJA1/Hsp40. Analysis of infected fibroblasts by real-time quantitative RT-PCR and Western blotting confirmed that EBNA3A, but not EBNA3C, induced expression of Hsp70, Hsp70B/B′, Bag3 and DNAJA1/Hsp40. This was also confirmed in a stable, inducible expression system. EBNA3A activated transcription from the Hsp70B promoter, but not multimerized heat-shock elements in transient transfection assays, consistent with specific chaperone and co-chaperone upregulation. Co-immunoprecipitation experiments suggest that EBNA3A can form a complex with the chaperone/co-chaperone proteins in both adenovirus-infected cells and EBV-immortalized lymphoblastoid cell lines. Consistent with this, induction of EBNA3A resulted in redistribution of Hsp70 from the cytoplasm to the nucleus. EBNA3A therefore specifically induces (and then interacts with) all of the factors necessary for an active Hsp70 chaperone complex.

scholarly journals Autorepression of Epstein-Barr Virus Nuclear Antigen 1 Expression by Inhibition of Pre-mRNA Processing

2007 ◽  
Vol 82 (4) ◽  
pp. 1679-1687 ◽  
Author(s):  
Mikio Yoshioka ◽  
Michelle M. Crum ◽  
Jeffery T. Sample
Keyword(s):  
Cell Lines ◽  
Epstein Barr Virus ◽  
Rna Binding ◽  
Cytotoxic T Cells ◽  
Nuclear Antigen ◽  
Genome Maintenance ◽  
Barr Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV) latent infection, and its associated oncogenic potential, is dependent on genome maintenance functions of EBV nuclear antigen 1 (EBNA-1), one of six EBNAs expressed from a common promoter (Wp and then Cp) upon infection of naive B cells. Subsequent host-mediated silencing, however, necessitates the expression of EBNA-1 from the EBNA-1-specific promoter Qp to ensure against genome loss during cell division, including EBV-associated malignancy. Here we addressed the mechanism by which EBNA-1 represses Qp through binding downstream of the transcription start site and the role of this autoregulatory function in EBV latency. Our results revealed that EBNA-1 does not inhibit transcription from Qp, as previously predicted, but acts post- or cotranscriptionally to block the processing of primary transcripts. This does not, however, require the RGG motifs responsible for strong but nonspecific RNA binding by EBNA-1. Within isogenic B-cell lines using either Cp/Wp or Qp, EBNA-1 occupancy of Qp is equivalent, suggesting that autoregulation occurs, albeit to different degrees, during full and restricted EBV latency programs. Finally, in cell lines using Cp or Wp for EBNA expression, unprocessed transcripts from Qp are detectable in the absence of corresponding mRNAs, providing further evidence that this novel mechanism of EBNA-1 action functions during latency. This posttranscriptional mechanism of regulation would provide an efficient means to monitor and regulate EBNA-1 expression from Qp, ensuring levels adequate for genome maintenance but, perhaps more importantly, below an immunogenic threshold above which latently infected cells may be at risk for elimination by EBNA-1-specific cytotoxic T cells.

scholarly journals Epstein–Barr virus nuclear antigen 1 is a DNA-binding protein with strong RNA-binding activity

2004 ◽  
Vol 85 (10) ◽  
pp. 2755-2765 ◽  
Author(s):  
Chih-Chung Lu ◽  
Chia-Wei Wu ◽  
Shin C. Chang ◽  
Tzu-Yi Chen ◽  
Chwan-Ren Hu ◽  
...  
Keyword(s):  
Dna Binding ◽  
Epstein Barr Virus ◽  
Rna Binding ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Binding Activity ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Infected Cells ◽  
Epstein Barr

Epstein–Barr virus (EBV) nuclear antigen 1 (EBNA-1) plays key roles in both the regulation of gene expression and the replication of the EBV genome in latently infected cells. To characterize the RNA-binding activity of EBNA-1, it was demonstrated that EBNA-1 binds efficiently to RNA homopolymers that are composed of poly(G) and weakly to those composed of poly(U). All three RGG boxes of EBNA-1 contributed additively to poly(G)-binding activity and could mediate RNA binding when attached to a heterologous protein in an RNA gel mobility-shift assay. In vitro-transcribed EBV and non-EBV RNA probes revealed that EBNA-1 bound to most RNAs examined and the affinity increased as the content of G and U increased, as demonstrated in competition assays. Among these probes, the 5′ non-coding region (NCR) (nt 131–278) of hepatitis C virus RNA appeared to be the strongest competitor for EBNA-1 binding to the EBV-encoded small nuclear RNA 1 (EBER1) probe, whereas a mutant 5′ NCR RNA with partially disrupted secondary structure was a weak competitor. Furthermore, the interaction of endogenous EBNA-1 and EBER1 in EBV-infected cells was demonstrated by a ribonucleoprotein immunoprecipitation assay. These results revealed that EBNA-1 is a DNA-binding protein with strong binding activity to a relatively broad spectrum of RNA and suggested an additional biological impact of EBNA-1 through its ability to bind to RNA.

scholarly journals Functional Cooperation of Epstein-Barr Virus Nuclear Antigen 2 and the Survival Motor Neuron Protein in Transactivation of the Viral LMP1 Promoter

2001 ◽  
Vol 75 (23) ◽  
pp. 11781-11790 ◽  
Author(s):  
Marc D. Voss ◽  
Annette Hille ◽  
Stephanie Barth ◽  
Andreas Spurk ◽  
Frank Hennrich ◽  
...  
Keyword(s):  
B Cells ◽  
Motor Neuron ◽  
Rna Polymerase Ii ◽  
Epstein Barr Virus ◽  
Target Genes ◽  
Survival Motor Neuron ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Coiled Bodies ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus nuclear antigen 2 (EBNA2) is essential for viral transformation of B cells and transactivates cellular and viral target genes by binding RBPJκ tethered to cognate promoter elements. EBNA2 interacts with the DEAD-box protein DP103 (DDX20/Gemin3), which in turn is complexed to the survival motor neuron (SMN) protein. SMN is implicated in RNA processing, but a role in transcriptional regulation has also been suggested. Here, we show that DP103 and SMN are complexed in B cells and that SMN coactivates the viral LMP promoter in the presence of EBNA2 in reporter gene assays and in vivo. Subcellular localization studies revealed that nuclear gems and/or coiled bodies containing DP103 and SMN are targeted by EBNA2. Protein-protein interaction experiments demonstrated that DP103 binds to SMN exon 6 and that both EBNA2 and SMN interact with the C terminus of DP103. Furthermore, a DP103 binding-deficient SMN mutant was released from nuclear gems and/or coiled bodies and further enhanced coactivation. In addition, impaired transactivation of a DP103 binding-deficient EBNA2 mutant was rescued by overexpression of SMN. Testing different promoter constructs in luciferase assays showed that RBPJκ is required but not sufficient for coactivation by EBNA2 and SMN. Overall, our data suggest that EBNA2 might target spliceosomal complexes by binding to DP103, thereby releasing SMN which subsequently exerts a coactivational function within the RNA-polymerase II transcription complex on the LMP1 promoter.

scholarly journals Epstein-Barr Virus Nuclear Antigen 3C Inhibits Expression ofCOBLL1and theADAM28-ADAMDEC1Locus via Interaction with the Histone Lysine Demethylase KDM2B

2018 ◽  
Vol 92 (21) ◽  
Author(s):  
Adam C. T. Gillman ◽  
Gillian Parker ◽  
Martin J. Allday ◽  
Quentin Bazot
Keyword(s):  
Transcriptional Repression ◽  
Epstein Barr Virus ◽  
Target Genes ◽  
Nuclear Antigen ◽  
Lymphoblastoid Cell Lines ◽  
Barr Virus ◽  
Histone Lysine ◽  
Histone Lysine Demethylase ◽  
Epstein Barr ◽  
Lysine Demethylase

ABSTRACTEpstein-Barr virus nuclear antigen 3C (EBNA3C) is a well-defined repressor of host gene expression in B cells transformed by Epstein-Barr virus (EBV) that cooperates with various cellular factors. It is established that EBNA3C interacts with the cellular factor RBPJ (RBP-Jκ or CBF1) through two distinct motifs: the TFGC motif, also called the homology domain (HD) motif, and the VWTP motif. In this study, we investigated the role of each motif in EBNA3C transcriptional repression activity by using two novel recombinant viruses with single RBPJ interaction motifs mutated (EBNA3C HDmut and EBNA3C W227S). Infection of primary B cells with either of these recombinant EBVs led to the successful establishment of lymphoblastoid cell lines (LCLs). Gene expression analysis showed that full repression of EBNA3C target genes is not achieved by EBNA3C HDmut compared to that with EBNA3C W227S or the EBNA3C wild type (WT). Focusing on the well-characterized EBNA3C-repressed genesCOBLL1,ADAM28, andADAMDEC1, we investigated the mechanism of EBNA3C-mediated transcriptional repression. Chromatin immunoprecipitation (ChIP) analysis indicated that EBNA3C HDmut is still able to recruit Polycomb proteins BMI1 and SUZ12 toCOBLL1as efficiently as EBNA3C WT does, leading to the full deposition of the repressive histone mark H3K27me3. However, we found that the activation-associated chromatin mark H3K4me3 is highly enriched at EBNA3C target genes in LCLs expressing EBNA3C HDmut. We show here that EBNA3C interacts with the histone lysine demethylase KDM2B and that this interaction is important for H3K4me3 removal and for the EBNA3C-mediated repression ofCOBLL1and theADAM28-ADAMDEC1locus.IMPORTANCEEBV is a virus associated with human cancers and is well known for its ability to transform B lymphocytes into continuously proliferating lymphoblastoid cell lines. EBNA3C is considered an oncoprotein and has been shown to be essential for B cell transformation by EBV. EBNA3C is well characterized as a viral transcription factor, but very little is known about its mechanisms of action. In the present study, we demonstrate that removal of the activating histone mark H3K4me3 and deposition of the repressive mark H3K27me3 by EBNA3C onCOBLL1are achieved by at least two distinct mechanisms. Furthermore, we discovered that EBNA3C interacts with the lysine demethylase KDM2B and that this interaction is important for its transcriptional repressive function. The findings in this study provide new insights into the mechanism used by the oncoprotein EBNA3C to repress cellular target genes.

scholarly journals Frequent latent Epstein-Barr virus infection of neoplastic T cells and bystander B cells in human immunodeficiency virus-negative European peripheral pleomorphic T-cell lymphomas

Blood ◽  
1993 ◽  
Vol 82 (1) ◽  
pp. 217-223 ◽  
Author(s):  
P Korbjuhn ◽  
I Anagnostopoulos ◽  
M Hummel ◽  
M Tiemann ◽  
F Dallenbach ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cell ◽  
Tumor Cells ◽  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Epstein Barr Virus Infection ◽  
Barr Virus ◽  
Immunodeficiency Virus ◽  
Infected Cells ◽  
Epstein Barr

We investigated 81 cases of peripheral pleomorphic T-cell lymphoma (PMTCL) occurring in human immunodeficiency virus-negative Europeans for the presence of Epstein-Barr virus (EBV)-DNA through polymerase chain reaction (PCR) for the presence of EBV-encoded small nuclear RNAs (EBER) and immediate early mRNAs (Bam H-fragment, lower strand frame [BHLF]) by in situ hybridization (ISH) and for EBV-encoded latent membrane protein (LMP) and nuclear antigen 2 (EBNA2) by immunohistology (IH). EBER-ISH, which could be applied on all cases, showed an overall incidence of EBV-infected cells in 38 of 81 cases (47%) of PMTCL. These data could be confirmed by PCR, which produced congruent results in the cases with amplifiable DNA. By EBER-ISH, the virus was located in the tumor cells in 30 of the 38 EBV-positive cases, with the proportion of the infected cells ranging from 1% to 100%. In 18 of these cases and in the 8 cases without EBV-infected tumor cells, the virus was, respectively, either additionally or exclusively detectable in occasional nonmalignant lymphoid bystander cells. An LMP expression was observed in several of the EBER-expressing tumor cells in 18 cases, whereas EBNA2 was detectable only in one case, which also displayed signs of viral replication. Some nonmalignant EBV-infected B immunoblasts also expressed LMP in several cases. Primary cutaneous and enteropathy-associated PMTCL displayed less frequent EBV infection when compared with other extranodal or nodal manifestations.

scholarly journals Epstein-Barr virus and human diseases: recent advances in diagnosis.

1988 ◽  
Vol 1 (3) ◽  
pp. 300-312 ◽  
Author(s):  
M Okano ◽  
G M Thiele ◽  
J R Davis ◽  
H L Grierson ◽  
D T Purtilo
Keyword(s):  
Epstein Barr Virus ◽  
Recent Decade ◽  
Burkitt’S Lymphoma ◽  
Burkitt's Lymphoma ◽  
Human Diseases ◽  
Nuclear Antigen ◽  
Barr Virus ◽  
Infected Cells ◽  
Epstein Barr

Since the discovery of Epstein-Barr virus (EBV) from a cultured Burkitt's lymphoma cell line in 1964, the virus has been associated with Burkitt's lymphoma, nasopharyngeal carcinoma, and infectious mononucleosis. During the recent decade, EBV has been etiologically implicated in a broad spectrum of human diseases. The precise role of this virus in these diseases is not well understood, but clearly, defective immunosurveillance against the virus may permit an uncontrolled proliferation of EBV-infected cells. As a result, a growing number of cases of EBV-associated B-cell proliferative diseases or lymphoma have been noted in patients with primary and acquired immunodeficiencies. These lymphoproliferative diseases and others, such as chronic mononucleosis syndrome, are leading to new areas of investigation which are providing information regarding the pathogenetic mechanisms of EBV-induced diseases. The early accurate diagnosis of EBV infection can be achieved by performing EBV-specific serology, detecting for EBV-determined nuclear antigen in tissues, establishing spontaneous lymphoid cell lines, and using molecular hybridization techniques for demonstrating the presence of viral genome in affected lesions.

Regulation of transcription by the Epstein–Barr virus nuclear antigen EBNA 2

2008 ◽  
Vol 36 (4) ◽  
pp. 625-628 ◽  
Author(s):  
Richard D. Palermo ◽  
Helen M. Webb ◽  
Andrea Gunnell ◽  
Michelle J. West
Keyword(s):  
Epstein Barr Virus ◽  
Cell Transformation ◽  
Nuclear Antigen ◽  
Regulation Of Transcription ◽  
Cyclin Dependent Kinase ◽  
Barr Virus ◽  
General Transcription Factors ◽  
Nuclear Antigens ◽  
Infected Cells ◽  
Epstein Barr

The EBNA 2 (Epstein–Barr nuclear antigen 2) transcription factor is essential for B-cell transformation by the cancer-associated EBV (Epstein–Barr virus) and for the continuous proliferation of infected cells. EBNA 2 activates transcription from the viral Cp (C promoter) during infection to generate the 120 kb transcript that encodes all nuclear antigens required for immortalization by EBV. EBNA 2 contains an acidic activation domain and can interact with a number of general transcription factors and co-activators. It is now becoming clear, however, that the regulation of transcription elongation in addition to initiation by EBNA 2, at least in part through CDK9 (cyclin-dependent kinase 9)-dependent phosphorylation of the RNA polymerase C-terminal domain, is likely to play a crucial role in the mechanism of action of this key viral protein.

Sign in / Sign up

Export Citation Format

Share Document