scholarly journals Nascent Transcriptomics Reveal Cellular Prolytic Factors Upregulated Upstream of the Latent-to-Lytic Switch Protein of Epstein-Barr Virus

2020 ◽  
Vol 94 (7) ◽  
Author(s):  
Tiffany R. Frey ◽  
Jozan Brathwaite ◽  
Xiaofan Li ◽  
Sandeepta Burgula ◽  
Ibukun A. Akinyemi ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Human Herpesvirus ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Viral Spread ◽  
Cellular Genes ◽  
Latently Infected ◽  
Infected Cells ◽  
Host Shutoff ◽  
Epstein Barr

ABSTRACT Lytic activation from latency is a key transition point in the life cycle of herpesviruses. Epstein-Barr virus (EBV) is a human herpesvirus that can cause lymphomas, epithelial cancers, and other diseases, most of which require the lytic cycle. While the lytic cycle of EBV can be triggered by chemicals and immunologic ligands, the lytic cascade is activated only when expression of the EBV latent-to-lytic switch protein ZEBRA is turned on. ZEBRA then transcriptionally activates other EBV genes and, together with some of those gene products, ensures completion of the lytic cycle. However, not every latently infected cell exposed to a lytic trigger turns on the expression of ZEBRA, resulting in responsive and refractory subpopulations. What governs this dichotomy? By examining the nascent transcriptome following exposure to a lytic trigger, we find that several cellular genes are transcriptionally upregulated temporally upstream of ZEBRA. These genes regulate lytic susceptibility to various degrees in latently infected cells that respond to mechanistically distinct lytic triggers. While increased expression of these cellular genes defines a prolytic state, such upregulation also runs counter to the well-known mechanism of viral-nuclease-mediated host shutoff that is activated downstream of ZEBRA. Furthermore, a subset of upregulated cellular genes is transcriptionally repressed temporally downstream of ZEBRA, indicating an additional mode of virus-mediated host shutoff through transcriptional repression. Thus, increased transcription of a set of host genes contributes to a prolytic state that allows a subpopulation of cells to support the EBV lytic cycle. IMPORTANCE Transition from latency to the lytic phase is necessary for herpesvirus-mediated pathology as well as viral spread and persistence in the population at large. Yet, viral genomes in only some cells in a population of latently infected cells respond to lytic triggers, resulting in subpopulations of responsive/lytic and refractory cells. Our investigations into this partially permissive phenotype of the herpesvirus Epstein-Barr virus (EBV) indicate that upon exposure to lytic triggers, certain cellular genes are transcriptionally upregulated, while viral latency genes are downregulated ahead of expression of the viral latent-to-lytic switch protein. These cellular genes contribute to lytic susceptibility to various degrees. Apart from indicating that there may be a cellular “prolytic” state, our findings indicate that (i) early transcriptional upregulation of cellular genes counters the well-known viral-nuclease-mediated host shutoff and (ii) subsequent transcriptional downregulation of a subset of early upregulated cellular genes is a previously undescribed mode of host shutoff.

scholarly journals Infection of Epstein–Barr Virus in Type III Latency Modulates Biogenesis of Exosomes and the Expression Profile of Exosomal miRNAs in the Burkitt Lymphoma Mutu Cell Lines

Cancers ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 237 ◽  
Author(s):  
Asuka Nanbo ◽  
Harutaka Katano ◽  
Michiyo Kataoka ◽  
Shiho Hoshina ◽  
Tsuyoshi Sekizuka ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Burkitt Lymphoma ◽  
Epstein Barr Virus ◽  
Type I ◽  
Type Iii ◽  
Barr Virus ◽  
Ebv Infection ◽  
Latently Infected ◽  
Infected Cells ◽  
Epstein Barr

Infection of Epstein–Barr virus (EBV), a ubiquitous human gamma herpesvirus, is associated with various malignancies in B lymphocytes and epithelial cells. EBV encodes 49 microRNAs in two separated regions, termed the BART and BHRF1 loci. Although accumulating evidence demonstrates that EBV infection regulates the profile of microRNAs in the cells, little is known about the microRNAs in exosomes released from infected cells. Here, we characterized the expression profile of intracellular and exosomal microRNAs in EBV-negative, and two related EBV-infected Burkitt lymphoma cell lines having type I and type III latency by next-generation sequencing. We found that the biogenesis of exosomes is upregulated in type III latently infected cells compared with EBV-negative and type I latently infected cells. We also observed that viral and several specific host microRNAs were predominantly incorporated in the exosomes released from the cells in type III latency. We confirmed that multiple viral microRNAs were transferred to the epithelial cells cocultured with EBV-infected B cells. Our findings indicate that EBV infection, in particular in type III latency, modulates the biogenesis of exosomes and the profile of exosomal microRNAs, potentially contributing to phenotypic changes in cells receiving these exosomes.

scholarly journals CD8+ immunodominance among Epstein-Barr virus lytic cycle antigens directly reflects the efficiency of antigen presentation in lytically infected cells

2005 ◽  
Vol 201 (3) ◽  
pp. 349-360 ◽  
Author(s):  
Victoria A. Pudney ◽  
Alison M. Leese ◽  
Alan B. Rickinson ◽  
Andrew D. Hislop
Keyword(s):  
T Cell ◽  
Epstein Barr Virus ◽  
Cd8 T Cell ◽  
Lytic Replication ◽  
Lytic Cycle ◽  
E Proteins ◽  
Barr Virus ◽  
Infected Cells ◽  
Epstein Barr ◽  
L Proteins

Antigen immunodominance is an unexplained feature of CD8+ T cell responses to herpesviruses, which are agents whose lytic replication involves the sequential expression of immediate early (IE), early (E), and late (L) proteins. Here, we analyze the primary CD8 response to Epstein-Barr virus (EBV) infection for reactivity to 2 IE proteins, 11 representative E proteins, and 10 representative L proteins, across a range of HLA backgrounds. Responses were consistently skewed toward epitopes in IE and a subset of E proteins, with only occasional responses to novel epitopes in L proteins. CD8+ T cell clones to representative IE, E, and L epitopes were assayed against EBV-transformed lymphoblastoid cell lines (LCLs) containing lytically infected cells. This showed direct recognition of lytically infected cells by all three sets of effectors but at markedly different levels, in the order IE > E ≫ L, indicating that the efficiency of epitope presentation falls dramatically with progress of the lytic cycle. Thus, EBV lytic cycle antigens display a hierarchy of immunodominance that directly reflects the efficiency of their presentation in lytically infected cells; the CD8+ T cell response thereby focuses on targets whose recognition leads to maximal biologic effect.

scholarly journals Functional Interaction between Epstein-Barr Virus Replication Protein Zta and Host DNA Damage Response Protein 53BP1

2009 ◽  
Vol 83 (21) ◽  
pp. 11116-11122 ◽  
Author(s):  
Sarah G. Bailey ◽  
Elizabeth Verrall ◽  
Celine Schelcher ◽  
Alex Rhie ◽  
Aidan J. Doherty ◽  
...  
Keyword(s):  
Dna Damage ◽  
Viral Replication ◽  
Epstein Barr Virus ◽  
Signal Transduction Pathway ◽  
Human Herpesvirus ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Proteomic Approach ◽  
Viral Genes ◽  
Epstein Barr

ABSTRACT Epstein-Barr virus (EBV; human herpesvirus 4) poses major clinical problems worldwide. Following primary infection, EBV enters a form of long-lived latency in B lymphocytes, expressing few viral genes, and it persists for the lifetime of the host with sporadic bursts of viral replication. The switch between latency and replication is governed by the action of a multifunctional viral protein Zta (also called BZLF1, ZEBRA, and Z). Using a global proteomic approach, we identified a host DNA damage repair protein that specifically interacts with Zta: 53BP1. 53BP1 is intimately connected with the ATM signal transduction pathway, which is activated during EBV replication. The interaction of 53BP1 with Zta requires the C-terminal ends of both proteins. A series of Zta mutants that show a wild-type ability to perform basic functions of Zta, such as dimer formation, interaction with DNA, and the transactivation of viral genes, were shown to have lost the ability to induce the viral lytic cycle. Each of these mutants also is compromised in the C-terminal region for interaction with 53BP1. In addition, the knockdown of 53BP1 expression reduced viral replication, suggesting that the association between Zta and 53BP1 is involved in the viral replication cycle.

Calcium modulation activates Epstein-Barr virus genome in latently infected cells

Science ◽  
1986 ◽  
Vol 232 (4757) ◽  
pp. 1554-1556 ◽  
Author(s):  
A Faggioni ◽  
C Zompetta ◽  
S Grimaldi ◽  
G Barile ◽  
L Frati ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Virus Genome ◽  
Barr Virus ◽  
Calcium Modulation ◽  
Latently Infected ◽  
Infected Cells ◽  
Epstein Barr

scholarly journals Cells Expressing the Epstein-Barr Virus Growth Program Are Present in and Restricted to the Naive B-Cell Subset of Healthy Tonsils

2000 ◽  
Vol 74 (21) ◽  
pp. 9964-9971 ◽  
Author(s):  
Alexandra M. Joseph ◽  
Gregory J. Babcock ◽  
David A. Thorley-Lawson
Keyword(s):  
B Cells ◽  
B Cell ◽  
Epstein Barr Virus ◽  
Cell Subset ◽  
Pcr Analysis ◽  
Virus Growth ◽  
Barr Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Epstein Barr

ABSTRACT In this paper we demonstrate, for the first time, that Epstein-Barr virus (EBV)-infected cells expressing the lymphoblastoid growth program are present in healthy carriers of the virus. Previously we observed that latently infected naive B cells are present in tonsils only when viral replication is detected, suggesting that these may represent newly infected B cells. We have tested this idea by performing a reverse transcription-PCR analysis for the expression of latent genes (EBNA2 and the EBNA3s) that are characteristically expressed only by newly infected cells expressing the growth latency program. EBNA2 expression is regularly detected in purified naive (IgD+) tonsillar B cells (13 of 16 tonsils tested) but was never found in the IgD− population (0 of 16). More detailed analysis revealed that the mRNAs for the latent genes EBNA1 (3 of 3 tonsils tested), EBNA3a (3 of 5), EBNA3b (3 of 5), EBNA3c (3 of 5), LMP1 (6 of 6), and LMP2 (5 of 6) were also present in the IgD+ population, but the EBNA1Q-K transcript, characteristic of nonlymphoblastoid forms of latency, was never detected (0 of 6). Finally, we demonstrate that the latently infected naive (IgD+) cells express CD80 (B7.1), a marker characteristically expressed on activated naive lymphoblasts but absent from resting naive B cells. The infected naive (IgD+) population in the tonsil therefore has the viral and cellular phenotype of a B-cell directly infected with EBV—an activated lymphoblast expressing the growth program.

Bryostatin 1 induces productive Epstein-Barr virus replication in latently infected cells: implications for use in immunocompromised patients

1993 ◽  
Vol 33 (1) ◽  
pp. 89-91 ◽  
Author(s):  
James P. Stewart ◽  
Alan T. McGown ◽  
Joseph Prendiville ◽  
George R. Pettit ◽  
Brian W. Fox ◽  
...  
Keyword(s):  
Virus Replication ◽  
Epstein Barr Virus ◽  
Immunocompromised Patients ◽  
Bryostatin 1 ◽  
Barr Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Epstein Barr

Induction of the Epstein-Barr virus (EBV) cycle in latently infected cells by n-butyrate

Virology ◽  
1979 ◽  
Vol 94 (1) ◽  
pp. 228-231 ◽  
Author(s):  
Janos Luka ◽  
Bengt Kallin ◽  
George Klein
Keyword(s):  
Epstein Barr Virus ◽  
Barr Virus ◽  
Latently Infected ◽  
Infected Cells ◽  
Epstein Barr

scholarly journals Epstein-Barr Virus–Infected Resting Memory B Cells, Not Proliferating Lymphoblasts, Accumulate in the Peripheral Blood of Immunosuppressed Patients

1999 ◽  
Vol 190 (4) ◽  
pp. 567-576 ◽  
Author(s):  
Gregory J. Babcock ◽  
Lisa L. Decker ◽  
Richard B. Freeman ◽  
David A. Thorley-Lawson
Keyword(s):  
B Cells ◽  
Peripheral Blood ◽  
Epstein Barr Virus ◽  
Memory B Cells ◽  
Barr Virus ◽  
Latently Infected ◽  
Immunosuppressed Patients ◽  
Infected Cells ◽  
Epstein Barr ◽  
Healthy Carriers

When Epstein-Barr virus (EBV) infects B cells in vitro, the result is a proliferating lymphoblast that expresses at least nine latent proteins. It is generally believed that these cells are rigorously controlled in vivo by cytotoxic T cells. Consistent with this, the latently infected cells in the peripheral blood of healthy carriers are not lymphoblasts. Rather, they are resting memory B cells that are probably not subject to direct immunosurveillance by cytotoxic T lymphocytes (CTLs). When patients become immunosuppressed, the viral load increases in the peripheral blood. The expansion of proliferating lymphoblasts due to the suppressed CTL response is believed to account for this increase and is considered to be a major risk factor for posttransplant lymphoproliferative disease (PTLD) and AIDS-associated B cell lymphoma. Here we show that there is an increase in the numbers of latently infected cells in the peripheral blood of immunosuppressed patients. However, the cells are not proliferating lymphoblasts. They are all latently infected, resting, memory B cells—the same population of infected cells found in the blood of healthy carriers. These results are discussed in the context of a model for EBV persistence that explains why PTLD is usually limited to the lymph nodes.

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.

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