scholarly journals The Dyad Symmetry Element of Epstein-Barr Virus Is a Dominant but Dispensable Replication Origin

PLoS ONE ◽  
2011 ◽  
Vol 6 (5) ◽  
pp. e18609 ◽  
Author(s):  
Elisabeth Ott ◽  
Paolo Norio ◽  
Marion Ritzi ◽  
Carl Schildkraut ◽  
Aloys Schepers
Keyword(s):  
Replication Origin ◽  
Epstein Barr Virus ◽  
Symmetry Element ◽  
Barr Virus ◽  
Epstein Barr ◽  
Dyad Symmetry

scholarly journals Specific Methylation Patterns in Two Control Regions of Epstein-Barr Virus Latency: the LMP-1-Coding Upstream Regulatory Region and an Origin of DNA Replication (oriP)

1998 ◽  
Vol 72 (4) ◽  
pp. 2969-2974 ◽  
Author(s):  
Kerstin I. Falk ◽  
Laszlo Szekely ◽  
Anna Aleman ◽  
Ingemar Ernberg
Keyword(s):  
Epstein Barr Virus ◽  
Methylation Status ◽  
Regulatory Region ◽  
Cell Types ◽  
Symmetry Element ◽  
Regulatory Sequence ◽  
Type I ◽  
Barr Virus ◽  
Epstein Barr ◽  
Dyad Symmetry

ABSTRACT The Epstein-Barr virus (EBV) can establish at least four different forms of latent infection. Previously, we have shown that the level of methylation of the EBV genome varies, depending on the form of latency. The methylation status of CpGs was analyzed by the bisulfite genomic sequencing technique in four different cell types representing different forms of latency. The dyad symmetry element of the origin of replication (oriP) region and the latent membrane protein 1 (LMP-1) regulatory sequence (LRS) were studied. The dyad symmetry element has four binding sites for EBNA-1. In a cell with type I latency, a region upstream of the dyad symmetry element was highly methylated, whereas the dyad symmetry element was unmethylated in the EBNA-1-binding region. The LRS was extensively methylated in the LMP-1-negative cell line Rael, in contrast to a LMP-1-expressing nasopharyngeal carcinoma tumor (NPC C15), which was almost completely unmethylated. The methylation pattern of LRS in type I and type III Burkitt lymphoma cells of similar parental origins confirmed that demethylation of some regions takes place upon phenotypic drift.

scholarly journals Activation of TRAF5 and TRAF6 Signal Cascades Negatively Regulates the Latent Replication Origin of Epstein-Barr Virus through p38 Mitogen-Activated Protein Kinase

2001 ◽  
Vol 75 (11) ◽  
pp. 5059-5068 ◽  
Author(s):  
Masaki Shirakata ◽  
Ken-Ichi Imadome ◽  
Kenji Okazaki ◽  
Kanji Hirai
Keyword(s):  
P38 Mapk ◽  
Replication Origin ◽  
Epstein Barr Virus ◽  
Suppressive Effect ◽  
Dominant Negative ◽  
Barr Virus ◽  
Extracellular Signals ◽  
Signal Cascade ◽  
Epstein Barr ◽  
Signal Cascades

ABSTRACT Latent Epstein-Barr virus (EBV) is maintained by the virus replication origin oriP that initiates DNA replication with the viral oriP-binding factor EBNA1. However, it is not known whether oriP's replicator activity is regulated by virus proteins or extracellular signals. By using a transient replication assay, we found that a low level of expression of viral signal transduction activator latent membrane protein 1 (LMP1) suppressed oriP activity. The binding site of the tumor necrosis factor receptor-associated factor (TRAF) of LMP1 was essential for this suppressive effect. Activation of the TRAF signal cascade by overexpression of TRAF5 and/or TRAF6 also suppressed oriPactivity. Conversely, blocking of TRAF signaling with dominant negative mutants of TRAF5 and TRAF6, as well as inhibition of a downstream signal mediator p38 MAPK, released the LMP1-inducedoriP suppression. Furthermore, activation of TRAF6 signal cascade by lipopolysaccharides (LPS) resulted in loss of EBV from Burkitt's lymphoma cell line Akata, and inhibition of p38 MAPK abolished the suppressive effect of LPS. These results suggested that the level of oriP activity is regulated by LMP1 and extracellular signals through TRAF5- and TRAF6-mediated signal cascades.

scholarly journals Telomere Repeat Binding Factors TRF1, TRF2, and hRAP1 Modulate Replication of Epstein-Barr Virus OriP

2003 ◽  
Vol 77 (22) ◽  
pp. 11992-12001 ◽  
Author(s):  
Zhong Deng ◽  
Constandache Atanasiu ◽  
John S. Burg ◽  
Dominique Broccoli ◽  
Paul M. Lieberman
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Epstein Barr Virus ◽  
Affinity Purification ◽  
Dominant Negative ◽  
Full Length ◽  
Barr Virus ◽  
Amino Terminal ◽  
Epstein Barr ◽  
Dyad Symmetry

ABSTRACT Epstein-Barr virus OriP confers cell cycle-dependent DNA replication and stable maintenance on plasmids in EBNA1-positive cells. The dyad symmetry region of OriP contains four EBNA1 binding sites that are punctuated by 9-bp repeats referred to as nonamers. Previous work has shown that the nonamers bind to cellular factors associated with human telomeres and contribute to episomal maintenance of OriP. In this work, we show that substitution mutation of all three nonamer sites reduces both DNA replication and plasmid maintenance of OriP-containing plasmids by 2.5- to 5-fold. The nonamers were required for high-affinity binding of TRF1, TRF2, and hRap1 to the dyad symmetry element but were not essential for the binding of EBNA1 as determined by DNA affinity purification from nuclear extracts. Chromatin immunoprecipitation assays indicated that TRF1, TRF2, and hRap1 bound OriP in vivo. Cell cycle studies indicate that TRF2 binding to OriP peaks in G1/S while TRF1 binding peaks in G2/M. OriP replication was inhibited by transfection of full-length TRF1 but not by deletion mutants lacking the myb DNA binding domain. In contrast, OriP replication was not affected by transfection of full-length TRF2 or hRap1 but was potently inhibited by dominant-negative TRF2 or hRap1 amino-terminal truncation mutants. Knockdown experiments with short interfering RNAs (siRNAs) directed against TRF2 and hRap1 severely reduced OriP replication, while TRF1 siRNA had a modest stimulatory effect on OriP replication. These results indicate that TRF2 and hRap1 promote, while TRF1 antagonizes, OriP-dependent DNA replication and suggest that these telomeric factors contribute to the establishment of replication competence at OriP.

scholarly journals Structural Basis for Cooperative Binding of EBNA1 to the Epstein-Barr Virus Dyad Symmetry Minimal Origin of Replication

2019 ◽  
Vol 93 (20) ◽  
Author(s):  
Kimberly A. Malecka ◽  
Jayaraju Dheekollu ◽  
Julianna S. Deakyne ◽  
Andreas Wiedmer ◽  
Ursula D. Ramirez ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Epstein Barr Virus ◽  
Latent Infection ◽  
Nuclear Antigen ◽  
Plasmid Replication ◽  
Origin Of Replication ◽  
Replication Machinery ◽  
Barr Virus ◽  
Epstein Barr ◽  
Dyad Symmetry

ABSTRACTEpstein-Barr virus is associated with several human malignancies, including nasopharyngeal carcinoma, gastric cancer, and lymphoma. Latently infected cells carry a circularized EBV episome where the origin of replication (oriP) is comprised of two elements: the family of repeats (FR) and dyad symmetry (DS). The viral protein Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) binds to FR and DS to promote EBV episome maintenance and DNA replication during latent infection in proliferating cells. EBNA1 binding to the DS constitutes a minimal origin of DNA replication. Here we report the crystal structure of two EBNA1 DNA-binding domain dimers bound to a DS half-site. This structure shows that the DNA is smoothly bent, allowing for stabilizing interactions between the dimers. The dimer-dimer interface requires an intricate hydrogen bonding network involving residues R491 and D581. When this interface is disrupted, we note loss of stable dimer-dimer complex formation on the DNA, compromisedoriP-containing plasmid replication in cells, and impaired recruitment of the MCM3 complex to theoriP. Surface conservation analysis reveals that these residues are part of a larger conserved surface that may be critical for recruitment of replication machinery to theoriP. Our results reveal a new region of EBNA1 critical for its activity and one that may be exploited by targeted small molecules to treat EBV-associated disease.IMPORTANCEEpstein-Barr virus (EBV) is a causative agent of various malignancies and may also contribute to autoimmune disease. The latent and episomal form of the virus is known to drive EBV-associated oncogenesis. Persistence of the viral episome in proliferating tumor cells requires the interaction of Epstein-Barr virus nuclear antigen 1 (EBNA1) with the viral origin of plasmid replication (oriP). The dyad symmetry (DS) element inoriPis the essential minimal replicator oforiP. Here we report the X-ray crystal structure of EBNA1 bound to DS. The structure reveals a previous unrecognized interface formed between dimers of EBNA1 necessary for cooperative DNA binding, recruitment of cellular replication machinery, and replication function. These findings provide new insights into the mechanism of EBNA1 function at the replication origin and new opportunities to inhibit EBV latent infection and pathogenesis.

A Quantitative Ultrastructural Study of Peripheral Blood Lymphocytes Containing Parallel Tubular Arrays in Epstein-Barr Virus and Cytomegalo-Virus Mononucleosis

1981 ◽  
Vol 39 ◽  
pp. 454-455
Author(s):  
C. M. Payne ◽  
P. M. Tennican
Keyword(s):  
Peripheral Blood ◽  
Lymphocyte Count ◽  
Epstein Barr Virus ◽  
Absolute Lymphocyte Count ◽  
Peripheral Blood Lymphocytes ◽  
Clinical State ◽  
Barr Virus ◽  
The Absolute ◽  
Epstein Barr ◽  
Tubular Arrays

In the normal peripheral circulation there exists a sub-population of lymphocytes which is ultrastructurally distinct. This lymphocyte is identified under the electron microscope by the presence of cytoplasmic microtubular-like inclusions called parallel tubular arrays (PTA) (Figure 1), and contains Fc-receptors for cytophilic antibody. In this study, lymphocytes containing PTA (PTA-lymphocytes) were quantitated from serial peripheral blood specimens obtained from two patients with Epstein -Barr Virus mononucleosis and two patients with cytomegalovirus mononucleosis. This data was then correlated with the clinical state of the patient.It was determined that both the percentage and absolute number of PTA- lymphocytes was highest during the acute phase of the illness. In follow-up specimens, three of the four patients' absolute lymphocyte count fell to within normal limits before the absolute PTA-lymphocyte count.In one patient who was followed for almost a year, the absolute PTA- lymphocyte count was consistently elevated (Figure 2). The estimation of absolute PTA-lymphocyte counts was determined to be valid after a morphometric analysis of the cellular areas occupied by PTA during the acute and convalescent phases of the disease revealed no statistical differences.

Studies of Epstein-Barr Virus Antigens Using Immunoperoxidase and Immunofluorescence Techniques

1975 ◽  
Vol 33 ◽  
pp. 342-343
Author(s):  
R. Stephens ◽  
K. Traul ◽  
D. Woolf ◽  
P. Gaudreau
Keyword(s):  
Electron Microscopy ◽  
Nasopharyngeal Carcinoma ◽  
Epstein Barr Virus ◽  
Barr Virus ◽  
If Technique ◽  
Infected Cells ◽  
Virus Antigens ◽  
Epstein Barr ◽  
Virus Capsid Antigen ◽  
Antigen Reactivity

A number of antigens have been found associated with persistent EBV infections of lymphoblastoid cells. Identification and localization of these antigens were principally by immunofluorescence (IF) techniques using sera from patients with nasopharyngeal carcinoma (NPC), Burkitt lymphoma (BL), and infectious mononucleosis (IM). Our study was mainly with three of the EBV related antigens, a) virus capsid antigen (VCA), b) membrane antigen (MA), and c) early antigens (EA) using immunoperoxidase (IP) techniques with electron microscopy (EM) to elucidate the sites of reactivity with EBV and EBV infected cells.Prior to labeling with horseradish peroxidase (HRP), sera from NPC, IM, and BL cases were characterized for various reactivities by the indirect IF technique. Modifications of the direct IP procedure described by Shabo and the indirect IP procedure of Leduc were made to enhance penetration of the cells and preservation of antigen reactivity.

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