scholarly journals The Role of the Epstein-Barr Virus Lytic Cycle in Tumor Progression: Consequences in Diagnosis and Therapy

2020 ◽  
Author(s):  
Emmanuel Drouet
Keyword(s):  
Tumor Progression ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Diagnosis And Therapy ◽  
Epstein Barr

scholarly journals Role of Rta in the Translation of Bicistronic BZLF1 of Epstein-Barr Virus

1998 ◽  
Vol 72 (6) ◽  
pp. 5128-5136 ◽  
Author(s):  
Pey-Jium Chang ◽  
Yu-Sun Chang ◽  
Shih-Tung Liu
Keyword(s):  
Epstein Barr Virus ◽  
Fusion Gene ◽  
Early Stage ◽  
Mrna Translation ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Bzlf1 Gene ◽  
Epstein Barr ◽  
Bicistronic Mrna

ABSTRACT The BZLF1 gene of Epstein-Barr virus (EBV), which encodes a transcription factor, Zta, is transcribed into monocistronic and bicistronic mRNAs from two different promoters during the immediate-early stage of the EBV lytic cycle. It is generally accepted that the Zta protein translated from the monocistronic mRNA profoundly influences the activation of the EBV lytic cycle. In this study, we constructed a plasmid, pCMV-RZLUC, which can transcribe a bicistronic mRNA consisting of BRLF1 and a BZLF1-luc fusion gene under latent conditions. P3HR1 cells transfected with this plasmid produce a luciferase activity which is approximately 17-fold higher than the activity exhibited by pRZLUC, a plasmid incapable of transcribing the bicistronic mRNA. Genetic analyses indicated that mutations in BRLF1 not only can decrease the translation of the fusion gene from the bicistronic mRNA but can also be complemented by a functional BRLF1 gene in cis. This observation implies that the product of BRLF1, Rta, is involved in the translation of the downstream gene. Results presented herein also demonstrate that these mutations cannot be complemented in trans with a plasmid overexpressing Rta, suggesting that the amount of Rta in the vicinity of the intercistronic region may be crucial for the translation. Furthermore, our results correspond to those of previous investigations indicating that the Zta protein can be translated from the bicistronic mRNA and that, similar to the translation of bicistronic ZLUC, mutations in BRLF1 also hinder the translation of Zta from the BRLF1-BZLF1 bicistronic mRNA. Translation of Zta from the bicistronic mRNA may play an essential role in the activation of the EBV lytic cycle.

scholarly journals Protein Kinase C-Independent Activation of the Epstein-Barr Virus Lytic Cycle

2002 ◽  
Vol 76 (11) ◽  
pp. 5612-5626 ◽  
Author(s):  
Lyndle Gradoville ◽  
David Kwa ◽  
Ayman El-Guindy ◽  
George Miller
Keyword(s):  
Phorbol Ester ◽  
Epstein Barr Virus ◽  
Hdac Inhibitors ◽  
Lytic Cycle ◽  
Early Gene ◽  
Immediate Early ◽  
Barr Virus ◽  
Kinase C ◽  
Epstein Barr

ABSTRACT The protein kinase C (PKC) pathway has been considered to be essential for activation of latent Epstein-Barr virus (EBV) into the lytic cycle. The phorbol ester tetradecanoyl phorbol acetate (TPA), a PKC agonist, is one of the best understood activators of EBV lytic replication. Zp, the promoter of the EBV immediate-early gene BZLF1, whose product, ZEBRA, drives the lytic cycle, contains several phorbol ester response elements. We investigated the role of the PKC pathway in lytic cycle activation in prototype cell lines that differed dramatically in their response to inducing agents. We determined whether PKC was involved in lytic cycle induction by histone deacetylase (HDAC) inhibitors. Consistent with prevailing views, B95-8 cells were activated into the lytic cycle by the phorbol ester TPA, via a PKC-dependent mechanism. B95-8 was not inducible by HDAC inhibitors such as n-butyrate and trichostatin A (TSA). Bisindolylmaleimide I, a selective PKC inhibitor, blocked lytic cycle activation in B95-8 cells in response to TPA. In marked contrast, in HH514-16 cells, the immediate-early promoters Zp and Rp were simultaneously activated by the HDAC inhibitors; TPA by itself failed to activate lytic gene expression. Inhibition of PKC activity by bisindolylmaleimide I did not block lytic cycle activation in HH514-16 cells by n-butyrate or TSA. In an extensive exploration of the mechanism underlying these different responses we found that the variable role of the PKC pathway in the two cell lines could not be accounted for by significant polymorphisms in the promoters of the immediate-early genes, by differences in the start sites of immediate-early gene transcription, or by differences in the nucleosomal organization of EBV DNA in the region of Zp or Rp. While B95-8 cells contained more total PKC activity than did HH514-16 cells in an in vitro assay, another EBV-transformed marmoset lymphoblastoid cell line, FF41, in which the lytic cycle was not inducible by TPA, contained comparably high levels of PKC activity. Moreover, two marmoset lymphoblastoid cells lines in which the lytic cycle could not be triggered by TPA maintained the same profile of EBV latency proteins as B95-8 cells. Thus, the profile of EBV latency proteins did not account for susceptibility to induction by PKC agonists. PKC activation is neither obligatory nor sufficient for the switch between latency and lytic cycle gene expression of EBV in many cell backgrounds. Lytic cycle induction by HDAC inhibitors proceeds by a PKC-independent mechanism.

scholarly journals Molecular Genetics in Epstein–Barr Virus-Associated Malignancies

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 593
Author(s):  
Srikanth Umakanthan ◽  
Maryann M Bukelo
Keyword(s):  
Epstein Barr Virus ◽  
Diagnostic Tools ◽  
Main Role ◽  
Genetic Changes ◽  
Barr Virus ◽  
Cancer Pathogenesis ◽  
Genomic Studies ◽  
Epstein Barr ◽  
Oncogenic Form

Global genomic studies have detected the role of genomic alterations in the pathogenesis of Epstein–Barr virus (EBV)-associated tumors. EBV oncoproteins cause a vital shift of EBV from an infectious virus to an oncogenic form during the latent and lytic phase within the lymphoid B cells and epithelial cells. This epigenetic alteration modulates the virus and host genomes and inactivates and disrupts numerous tumor suppressors and signaling pathways. Genomic profiling has played the main role in identifying EBV cancer pathogenesis and its related targeted therapies. This article reviews the role of genetic changes in EBV-associated lymphomas and carcinomas. This includes the prolific molecular genesis, key diagnostic tools, and target-specific drugs that have been in recent clinical use.

EBV load is associated with cfDNA fragmentation and renal damage in SLE patients

Lupus ◽  
2021 ◽  
pp. 096120332110103
Author(s):  
Anna Truszewska ◽  
Agnieszka Wirkowska ◽  
Kamila Gala ◽  
Piotr Truszewski ◽  
Łucja Krzemień-Ojak ◽  
...  
Keyword(s):  
Kidney Disease ◽  
Lupus Erythematosus ◽  
Epstein Barr Virus ◽  
Renal Damage ◽  
Healthy Individuals ◽  
Pcr Assay ◽  
Barr Virus ◽  
Fragmentation Index ◽  
Epstein Barr

Background For long Epstein–Barr virus (EBV) has been suspected to be involved in the pathogenesis of systemic lupus erythematosus (SLE). The aim of this study was to verify the association between EBV, cell-free DNA (cfDNA) and kidney disease in SLE. Methods Blood samples were obtained from 43 SLE patients and 50 healthy individuals. EBV load was measured via real-time PCR assay. Sizing and quantification of plasma cfDNA was performed on Bioanalyzer. We proposed that the uniformity of cfDNA fragmentation can be described using cfDNA fragmentation index. Results SLE patients with chronic kidney disease (CKD +) had higher EBV load compared to CKD(–) patients (P = 0.042). Patients with high cfDNA level had higher EBV load (P = 0.041) and higher cfDNA fragmentation index (P < 0.001) compared to patients with low cfDNA level. Among patients with high cfDNA level, EBV load was higher in CKD(+) group compared to CKD(–) group (P = 0.035). EBV load was positively correlated with the fragmentation index in all SLE patients (P = 0.028, R2 = 0.13), and the correlation was even more pronounced in CKD (+) patients (P < 0.001, R2 = 0.20). Conclusions We showed that EBV load was associated with non-uniform cfDNA fragmentation, higher cfDNA levels, and kidney disease in SLE patients. Although the causality of this relationship could not be determined with the current study, it brings rationale for further investigations on the role of EBV and cfDNA interplay in SLE pathogenesis.

DNA-binding-defective mutants of the Epstein-Barr virus lytic switch activator Zta transactivate with altered specificities

1994 ◽  
Vol 14 (5) ◽  
pp. 3041-3052
Author(s):  
E K Flemington ◽  
J P Lytle ◽  
C Cayrol ◽  
A M Borras ◽  
S H Speck
Keyword(s):  
Dna Binding ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Promoter Elements ◽  
Barr Virus ◽  
Binding Forms ◽  
Viral Genes ◽  
Direct Binding ◽  
Epstein Barr ◽  
Necessary And Sufficient

The Epstein-Barr virus BRLF1 and BZLF1 genes are the first viral genes transcribed upon induction of the viral lytic cycle. The protein products of both genes (referred to here as Rta and Zta, respectively) activate expression of other viral genes, thereby initiating the lytic cascade. Among the viral antigens expressed upon induction of the lytic cycle, however, Zta is unique in its ability to disrupt viral latency; expression of the BZLF1 gene is both necessary and sufficient for triggering the viral lytic cascade. We have previously shown that Zta can activate its own promoter (Zp), through binding to two Zta recognition sequences (ZIIIA and ZIIIB). Here we describe mutant Zta proteins that do not bind DNA (referred to as Zta DNA-binding mutants [Zdbm]) but retain the ability to transactivate Zp. Consistent with the inability of these mutants to bind DNA, transactivation of Zp by Zdbm is not dependent on the Zta recognition sequences. Instead, transactivation by Zdbm is dependent upon promoter elements that bind cellular factors. An examination of other viral and cellular promoters identified promoters that are weakly responsive or unresponsive to Zdbm. An analysis of a panel of artificial promoters containing one copy of various promoter elements demonstrated a specificity for Zdbm activation that is distinct from that of Zta. These results suggest that non-DNA-binding forms of some transactivators retain the ability to transactivate specific target promoters without direct binding to DNA.

scholarly journals Progression of understanding for the role of Epstein-Barr virus and management of nasopharyngeal carcinoma

2017 ◽  
Vol 36 (3) ◽  
pp. 435-447 ◽  
Author(s):  
Yosuke Nakanishi ◽  
Naohiro Wakisaka ◽  
Satoru Kondo ◽  
Kazuhira Endo ◽  
Hisashi Sugimoto ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Epstein Barr Virus ◽  
Barr Virus ◽  
Epstein Barr
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