scholarly journals Initiation of lytic DNA replication in Epstein–Barr virus: search for a common family mechanism

2010 ◽  
Vol 5 (1) ◽  
pp. 65-83 ◽  
Author(s):  
Andrew J Rennekamp ◽  
Paul M Lieberman
Keyword(s):  
Dna Replication ◽  
Epstein Barr Virus ◽  
Barr Virus ◽  
Epstein Barr ◽  
Lytic Dna Replication

scholarly journals Characterization of the Uracil-DNA Glycosylase Activity of Epstein-Barr Virus BKRF3 and Its Role in Lytic Viral DNA Replication

2006 ◽  
Vol 81 (3) ◽  
pp. 1195-1208 ◽  
Author(s):  
Chih-Chung Lu ◽  
Ho-Ting Huang ◽  
Jiin-Tarng Wang ◽  
Geir Slupphaug ◽  
Tsai-Kun Li ◽  
...  
Keyword(s):  
Dna Replication ◽  
Epstein Barr Virus ◽  
Efficient Production ◽  
Transcription Activator ◽  
Viral Dna ◽  
Barr Virus ◽  
Epstein Barr ◽  
Lytic Dna Replication

ABSTRACT Uracil-DNA glycosylases (UDGs) of the uracil-N-glycosylase (UNG) family are the primary DNA repair enzymes responsible for removal of inappropriate uracil from DNA. Recent studies further suggest that the nuclear human UNG2 and the UDGs of large DNA viruses may coordinate with their DNA polymerase accessory factors to enhance DNA replication. Based on its amino acid sequence, the putative UDG of Epstein-Barr virus (EBV), BKRF3, belongs to the UNG family of proteins, and it was demonstrated previously to enhance oriLyt-dependent DNA replication in a cotransfection replication assay. However, the expression and enzyme activity of EBV BKRF3 have not yet been characterized. In this study, His-BKRF3 was expressed in bacteria and purified for biochemical analysis. Similar to the case for the Escherichia coli and human UNG enzymes, His-BKRF3 excised uracil from single-stranded DNA more efficiently than from double-stranded DNA and was inhibited by the purified bacteriophage PBS1 inhibitor Ugi. In addition, BKRF3 was able to complement an E. coli ung mutant in rifampin and nalidixic acid resistance mutator assays. The expression kinetics and subcellular localization of BKRF3 products were detected in EBV-positive lymphoid and epithelial cells by using BKRF3-specific mouse antibodies. Expression of BKRF3 is regulated mainly by the immediate-early transcription activator Rta. The efficiency of EBV lytic DNA replication was slightly affected by BKRF3 small interfering RNA (siRNA), whereas cellular UNG2 siRNA or inhibition of cellular and viral UNG activities by expressing Ugi repressed EBV lytic DNA replication. Taking these results together, we demonstrate the UNG activity of BKRF3 in vitro and in vivo and suggest that UNGs may participate in DNA replication or repair and thereby promote efficient production of viral DNA.

scholarly journals Protein Array Identification of Substrates of the Epstein-Barr Virus Protein Kinase BGLF4

2009 ◽  
Vol 83 (10) ◽  
pp. 5219-5231 ◽  
Author(s):  
Jian Zhu ◽  
Gangling Liao ◽  
Liang Shan ◽  
Jun Zhang ◽  
Mei-Ru Chen ◽  
...  
Keyword(s):  
Dna Replication ◽  
Protein Kinase ◽  
Epstein Barr Virus ◽  
Protein Array ◽  
Lytic Cycle ◽  
Virus Protein ◽  
Barr Virus ◽  
Epstein Barr ◽  
Lytic Dna Replication ◽  
In Cells

ABSTRACT A conserved family of herpesvirus protein kinases plays a crucial role in herpesvirus DNA replication and virion production. However, despite the fact that these kinases are potential therapeutic targets, no systematic studies have been performed to identify their substrates. We generated an Epstein-Barr virus (EBV) protein array to evaluate the targets of the EBV protein kinase BGLF4. Multiple proteins involved in EBV lytic DNA replication and virion assembly were identified as previously unrecognized substrates for BGLF4, illustrating the broad role played by this protein kinase. Approximately half of the BGLF4 targets were also in vitro substrates for the cellular kinase CDK1/cyclin B. Unexpectedly, EBNA1 was identified as a substrate and binding partner of BGLF4. EBNA1 is essential for replication and maintenance of the episomal EBV genome during latency. BGLF4 did not prevent EBNA1 binding to sites in the EBV latency origin of replication, oriP. Rather, we found that BGLF4 was recruited by EBNA1 to oriP in cells transfected with an oriP vector and BGLF4 and in lytically induced EBV-positive Akata cells. In cells transfected with an oriP vector, the presence of BGLF4 led to more rapid loss of the episomal DNA, and this was dependent on BGLF4 kinase activity. Similarly, expression of doxycycline-inducible BGLF4 in Akata cells led to a reduction in episomal EBV genomes. We propose that BGLF4 contributes to effective EBV lytic cycle progression, not only through phosphorylation of EBV lytic DNA replication and virion proteins, but also by interfering with the EBNA1 replication function.

scholarly journals Essential Role of Rta in Lytic DNA Replication of Epstein-Barr Virus

2012 ◽  
Vol 87 (1) ◽  
pp. 208-223 ◽  
Author(s):  
A. El-Guindy ◽  
M. Ghiassi-Nejad ◽  
S. Golden ◽  
H.-J. Delecluse ◽  
G. Miller
Keyword(s):  
Dna Replication ◽  
Epstein Barr Virus ◽  
Essential Role ◽  
Barr Virus ◽  
Epstein Barr ◽  
Lytic Dna Replication

scholarly journals Tenofovir prodrugs potently inhibit Epstein–Barr virus lytic DNA replication by targeting the viral DNA polymerase

2020 ◽  
Vol 117 (22) ◽  
pp. 12368-12374 ◽  
Author(s):  
Natalia C. Drosu ◽  
Elazer R. Edelman ◽  
David E. Housman
Keyword(s):  
Dna Replication ◽  
Disease Prevention ◽  
Dna Polymerase ◽  
Epstein Barr Virus ◽  
Suppressive Therapy ◽  
Barr Virus ◽  
Acyclovir Treatment ◽  
Lytic Reactivation ◽  
Epstein Barr ◽  
Lytic Dna Replication

Epstein–Barr virus (EBV) is a ubiquitous human γ-herpesvirus that establishes life-long infection and increases the risk for the development of several cancers and autoimmune diseases. The mechanisms by which chronic EBV infection leads to subsequent disease remain incompletely understood. Lytic reactivation plays a central role in the development of EBV-driven cancers and may contribute to other EBV-associated diseases. Thus, the clinical use of antivirals as suppressive therapy for EBV lytic reactivation may aid efforts aimed at disease prevention. Current antivirals for EBV have shown limited clinical utility due to low potency or high toxicity, leaving open the need for potent antivirals suitable for long-term prophylaxis. In the present study, we show that tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF), drugs with excellent safety profiles used clinically for HIV prevention, inhibit EBV lytic DNA replication, with respective IC50values of 0.30 μM and 84 nM. In a cell-based assay, TAF was 35- and 24-fold and TDF was 10- and 7-fold more potent than acyclovir and penciclovir, respectively, and TAF was also twice as potent as ganciclovir. The active metabolite of tenofovir prodrugs, tenofovir-diphosphate, inhibited the incorporation of dATP into a primed DNA template by the EBV DNA polymerase in vitro. In contrast to acyclovir, treatment of cells during latency for 24 h with TAF still inhibited EBV lytic DNA replication at 72 h after drug was removed. Our results suggest that tenofovir prodrugs may be particularly effective as inhibitors of EBV lytic reactivation, and that clinical studies to address critical questions about disease prevention are warranted.

scholarly journals Xeroderma pigmentosum C is involved in Epstein–Barr virus DNA replication

2007 ◽  
Vol 88 (12) ◽  
pp. 3234-3243 ◽  
Author(s):  
Chih-Chung Lu ◽  
Yi-Chun Chen ◽  
Jiin-Tarng Wang ◽  
Pei-Wen Yang ◽  
Mei-Ru Chen
Keyword(s):  
Dna Repair ◽  
Dna Replication ◽  
Xeroderma Pigmentosum ◽  
Epstein Barr Virus ◽  
Excision Repair ◽  
Mutant Cell ◽  
Dependent Manner ◽  
Barr Virus ◽  
Epstein Barr ◽  
Lytic Dna Replication

Cellular mismatch and base-excision repair machineries have been shown to be involved in Epstein–Barr Virus (EBV) lytic DNA replication. We report here that nucleotide-excision repair (NER) may also play an important role in EBV lytic DNA replication. Firstly, the EBV BGLF4 kinase interacts with xeroderma pigmentosum C (XPC), the critical DNA damage-recognition factor of NER, in yeast and in vitro, as demonstrated by yeast two-hybrid and glutathione S-transferase pull-down assays. Simultaneously, XPC was shown, by indirect immunofluorescence and co-immunoprecipitation assays, to interact and colocalize with BGLF4 in EBV-positive NA cells undergoing lytic viral replication. In addition, the efficiency of EBV DNA replication was reduced about 30–40 % by an XPC small interfering RNA. Expression of BGLF4 enhances cellular DNA-repair activity in p53-defective H1299/bcl2 cells in a host-cell reactivation assay. This enhancement was not observed in the XPC-mutant cell line XP4PA-SV unless complemented by ectopic XPC, suggesting that BGLF4 may stimulate DNA repair in an XPC-dependent manner. Overall, we suggest that the interaction of BGLF4 and XPC may be involved in DNA replication and repair and thereby enhance the efficiency of viral DNA replication.

scholarly journals DNA Damage Signaling Is Induced in the Absence of Epstein—Barr Virus (EBV) Lytic DNA Replication and in Response to Expression of ZEBRA

PLoS ONE ◽  
2015 ◽  
Vol 10 (5) ◽  
pp. e0126088 ◽  
Author(s):  
Ruth Wang'ondu ◽  
Stuart Teal ◽  
Richard Park ◽  
Lee Heston ◽  
Henri Delecluse ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Epstein Barr Virus ◽  
Barr Virus ◽  
Dna Damage Signaling ◽  
Epstein Barr ◽  
Lytic Dna Replication
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