scholarly journals A transcription factor with homology to the AP-1 family links RNA transcription and DNA replication in the lytic cycle of Epstein-Barr virus.

1993 ◽  
Vol 12 (10) ◽  
pp. 3921-3929 ◽  
Author(s):  
A. Schepers ◽  
D. Pich ◽  
W. Hammerschmidt
Keyword(s):  
Transcription Factor ◽  
Dna Replication ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Rna Transcription ◽  
Barr Virus ◽  
Epstein Barr

scholarly journals An Epigenetic Journey: Epstein-Barr Virus Transcribes Chromatinized and Subsequently Unchromatinized Templates during Its Lytic Cycle

2019 ◽  
Vol 93 (8) ◽  
Author(s):  
Adityarup Chakravorty ◽  
Bill Sugden ◽  
Eric C. Johannsen
Keyword(s):  
Gene Expression ◽  
Dna Replication ◽  
Epstein Barr Virus ◽  
Dna Amplification ◽  
Lytic Cycle ◽  
Late Gene ◽  
Late Gene Expression ◽  
Viral Dna ◽  
Barr Virus ◽  
Epstein Barr

ABSTRACTThe Epstein-Barr virus (EBV) lytic phase, like those of all herpesviruses, proceeds via an orderly cascade that integrates DNA replication and gene expression. EBV early genes are expressed independently of viral DNA amplification, and several early gene products facilitate DNA amplification. On the other hand, EBV late genes are defined by their dependence on viral DNA replication for expression. Recently, a set of orthologous genes found in beta- and gammaherpesviruses have been determined to encode a viral preinitiation complex (vPIC) that mediates late gene expression. The EBV vPIC requires an origin of lytic replication incis, implying that the vPIC mediates transcription from newly replicated DNA. In agreement with this implication, EBV late gene mRNAs localize to replication factories. Notably, these factories exclude canonical histones. In this review, we compare and contrast the mechanisms and epigenetics of EBV early and late gene expression. We summarize recent findings, propose a model explaining the dependence of EBV late gene expression on lytic DNA amplification, and suggest some directions for future study.

scholarly journals Evidence for DNA Hairpin Recognition by Zta at the Epstein-Barr Virus Origin of Lytic Replication

2010 ◽  
Vol 84 (14) ◽  
pp. 7073-7082 ◽  
Author(s):  
Andrew J. Rennekamp ◽  
Pu Wang ◽  
Paul M. Lieberman
Keyword(s):  
Dna Replication ◽  
Inverted Repeat ◽  
Epstein Barr Virus ◽  
Lytic Replication ◽  
Lytic Cycle ◽  
Productive Infection ◽  
Dna Hairpin ◽  
Barr Virus ◽  
Early Protein ◽  
Epstein Barr

ABSTRACT The Epstein-Barr virus immediate-early protein (Zta) plays an essential role in viral lytic activation and pathogenesis. Zta is a basic zipper (b-Zip) domain-containing protein that binds multiple sites in the viral origin of lytic replication (OriLyt) and is required for lytic-cycle DNA replication. We present evidence that Zta binds to a sequence-specific, imperfect DNA hairpin formed by an inverted repeat within the upstream essential element (UEE) of OriLyt. Mutations in the OriLyt sequence that are predicted to disrupt hairpin formation also disrupt Zta binding in vitro. Restoration of the hairpin rescues the defect. We also show that OriLyt DNA isolated from replicating cells contains a nuclease-sensitive region that overlaps with the inverted-repeat region of the UEE. Furthermore, point mutations in Zta that disrupt specific recognition of the UEE hairpin are defective for activation of lytic replication. These data suggest that Zta acts by inducing and/or stabilizing a DNA hairpin structure during productive infection. The DNA hairpin at OriLyt with which Zta interacts resembles DNA structures formed at other herpesvirus origins and may therefore represent a common secondary structure used by all herpesvirus family members during the initiation of DNA replication.

scholarly journals Identification and Characterization of the Physiological Gene Targets of the Essential Lytic Replicative Epstein-Barr Virus SM Protein

2015 ◽  
Vol 90 (3) ◽  
pp. 1206-1221 ◽  
Author(s):  
Jacob Thompson ◽  
Dinesh Verma ◽  
DaJiang Li ◽  
Tim Mosbruger ◽  
Sankar Swaminathan
Keyword(s):  
Dna Replication ◽  
Mechanism Of Action ◽  
Epstein Barr Virus ◽  
Rna Binding ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Ebv Dna ◽  
Epstein Barr ◽  
Sm Protein ◽  
Target Rna

ABSTRACTEpstein-Barr virus (EBV) SM protein is an essential lytic cycle protein with multiple posttranscriptional mechanisms of action. SM binds RNA and increases accumulation of specific EBV transcripts. Previous studies using microarrays and PCR have shown that SM-null mutants fail to accumulate several lytic cycle mRNAs and proteins at wild-type levels. However, the complete effect of SM on the EBV transcriptome has been incompletely characterized. Here we precisely identify the effects of SM on all EBV transcripts by high-throughput RNA sequencing, quantitative PCR (qPCR), and Northern blotting. The effect of SM on EBV mRNAs was highly skewed and was most evident on 13 late genes, demonstrating why SM is essential for infectious EBV production. EBV DNA replication was also partially impaired in SM mutants, suggesting additional roles for SM in EBV DNA replication. While it has been suggested that SM specificity is based on recognition of either RNA sequence motifs or other sequence properties, no such unifying property of SM-responsive targets was discernible. The binding affinity of mRNAs for SM also did not correlate with SM responsiveness. These data suggest that while target RNA binding by SM may be required for its effect, specific activation by SM is due to differences in inherent properties of individual transcripts. We therefore propose a new model for the mechanism of action and specificity of SM and its homologs in other herpesviruses: that they bind many RNAs but only enhance accumulation of those that are intrinsically unstable and poorly expressed.IMPORTANCEThis study examines the mechanism of action of EBV SM protein, which is essential for EBV replication and infectious virus production. Since SM protein is not similar to any cellular protein and has homologs in all other human herpesviruses, it has potential importance as a therapeutic target. Here we establish which EBV RNAs are most highly upregulated by SM, allowing us to understand why it is essential for EBV replication. By comparing and characterizing these RNA transcripts, we conclude that the mechanism of specific activity is unlikely to be based simply on preferential recognition of a target motif. Rather, SM binding to its target RNA may be necessary but not sufficient for enhancing accumulation of the RNA. Preferential effects of SM on its most responsive RNA targets may depend on other inherent characteristics of these specific mRNAs that require SM for efficient expression, such as RNA stability.

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 Interaction sites of the Epstein–Barr virus Zta transcription factor with the host genome in epithelial cells

2021 ◽  
Vol 3 (11) ◽  
Author(s):  
Anja Godfrey ◽  
Kay Osborn ◽  
Alison J. Sinclair
Keyword(s):  
Transcription Factor ◽  
B Cells ◽  
Epithelial Cells ◽  
Binding Sites ◽  
Epstein Barr Virus ◽  
Lytic Replication ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Epstein Barr ◽  
The Impact

Epstein–Barr virus (EBV) is present in a state of latency in infected memory B-cells and EBV-associated lymphoid and epithelial cancers. Cell stimulation or differentiation of infected B-cells and epithelial cells induces reactivation to the lytic replication cycle. In each cell type, the EBV transcription and replication factor Zta (BZLF1, EB1) plays a role in mediating the lytic cycle of EBV. Zta is a transcription factor that interacts directly with Zta response elements (ZREs) within viral and cellular genomes. Here we undertake chromatin-precipitation coupled to DNA-sequencing (ChIP-Seq) of Zta-associated DNA from cancer-derived epithelial cells. The analysis identified over 14 000 Zta-binding sites in the cellular genome. We assessed the impact of lytic cycle reactivation on changes in gene expression for a panel of Zta-associated cellular genes. Finally, we compared the Zta-binding sites identified in this study with those previously identified in B-cells and reveal substantial conservation in genes associated with Zta-binding sites.

scholarly journals Interaction with the Epstein-Barr Virus Helicase Targets Zta to DNA Replication Compartments

2001 ◽  
Vol 75 (18) ◽  
pp. 8792-8802 ◽  
Author(s):  
Gangling Liao ◽  
Frederick Y. Wu ◽  
S. Diane Hayward
Keyword(s):  
Dna Replication ◽  
Epstein Barr Virus ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Lytic Cycle ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Barr Virus ◽  
Epstein Barr ◽  
Green Fluorescent

ABSTRACT Zta has a dual role in the Epstein-Barr virus (EBV) lytic cycle, acting as a key regulator of EBV lytic gene expression and also being essential for lytic viral DNA replication. Zta's replication function is mediated in part through interactions with the core viral replication proteins. We now show interaction between Zta and the helicase (BBLF4) and map the binding region to within amino acids (aa) 22 to 86 of the Zta activation domain. In immunofluorescence assays, green fluorescent protein (GFP)-tagged BBLF4 localized to the cytoplasm of transfected cells. Cotransfection of Zta resulted in translocation of BBLF4-GFP into the nucleus indicating interaction between these two proteins. However, Zta with a deletion of aa 24 to 86 was unable to mediate nuclear translocation of BBLF4-GFP. Results obtained with Zta variants carrying deletions across the aa 24 to 86 region indicated more than one contact site for BBLF4 within this domain, and this was reinforced by the behavior of the four-point mutant Zta (m22/26,74/75), which was severely impaired for BBLF4 interaction. Binding of BBLF4 to Zta was confirmed using GST affinity assays. In both cotransfection-replication assays and replication assays performed in EBV-positive P3HR1 cells, the Zta (m22/26,74/75) mutant was replication defective. In Zta-transfected D98-HR1 cells, replication compartments could be detected by immunofluorescence staining using anti-BMRF1 monoclonal antibody. Cells transfected with Zta variants that were defective for helicase binding still formed replication compartments, but Zta was excluded from these compartments. These experiments reveal a role for the Zta-helicase interaction in targeting Zta to sites of viral DNA replication.

scholarly journals Topoisomerase I and RecQL1 Function in Epstein-Barr Virus Lytic Reactivation

2009 ◽  
Vol 83 (16) ◽  
pp. 8090-8098 ◽  
Author(s):  
Pu Wang ◽  
Andrew J. Rennekamp ◽  
Yan Yuan ◽  
Paul M. Lieberman
Keyword(s):  
Dna Replication ◽  
Topoisomerase I ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Early Protein ◽  
Viral Promoters ◽  
Epstein Barr ◽  
Topo Ii

ABSTRACT Cellular topoisomerases and helicases are thought to play an essential role in herpesvirus replication and gene expression and are considered to be potential targets for antiviral therapies. Topoisomerase I (Topo I) and Topo II inhibitors can selectively inhibit Epstein-Barr virus (EBV) lytic cycle DNA replication. We found that the Topo I inhibitor camptothecin and, to a lesser extent, the Topo II inhibitor etoposide are potent inhibitors of the transcription and replication function of the EBV-encoded immediate-early protein Zta (also referred to as ZEBRA, EB1, and BZLF1). Camptothecin inhibited the Zta transcription activation of endogenous and reporter-linked viral promoters. Small interfering RNA depletion of Topo I also inhibited the Zta-dependent activation of lytic cycle DNA replication. Topo I could be coimmunoprecipitated with Zta, but this interaction was restricted to EBV-positive cells, suggesting that other viral proteins stabilize the interaction between Zta and Topo I. We also found that the RecQL1 helicase, which is known to associate with Kaposi's sarcoma-associated herpesvirus (KSHV) OriLyt, interacts with EBV OriLyt. Treatment with camptothecin reduced both Zta and RecQL1 binding to OriLyt in vivo, suggesting that Topo I promotes replication protein assembly at OriLyt.

scholarly journals HCF1 and OCT2 Cooperate with EBNA1 To Enhance OriP-Dependent Transcription and Episome Maintenance of Latent Epstein-Barr Virus

2016 ◽  
Vol 90 (11) ◽  
pp. 5353-5367 ◽  
Author(s):  
Jayaraju Dheekollu ◽  
Andreas Wiedmer ◽  
Daniel Sentana-Lledo ◽  
Joel Cassel ◽  
Troy Messick ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Epstein Barr Virus ◽  
Histone H3 ◽  
Type I ◽  
Barr Virus ◽  
Cellular Factors ◽  
Epstein Barr ◽  
Simplex Virus

ABSTRACTEpstein-Barr virus (EBV) establishes latent infections as multicopy episomes with complex patterns of viral gene transcription and chromatin structure. The EBV origin of plasmid replication (OriP) has been implicated as a critical control element for viral transcription, as well as viral DNA replication and episome maintenance. Here, we examine cellular factors that bind OriP and regulate histone modification, transcription regulation, and episome maintenance. We found that OriP is enriched for histone H3 lysine 4 (H3K4) methylation in multiple cell types and latency types. Host cell factor 1 (HCF1), a component of the mixed-lineage leukemia (MLL) histone methyltransferase complex, and transcription factor OCT2 (octamer-binding transcription factor 2) bound cooperatively with EBNA1 (Epstein-Barr virus nuclear antigen 1) at OriP. Depletion of OCT2 or HCF1 deregulated latency transcription and histone modifications at OriP, as well as the OriP-regulated latency type-dependent C promoter (Cp) and Q promoter (Qp). HCF1 depletion led to a loss of histone H3K4me3 (trimethylation of histone H3 at lysine 4) and H3 acetylation at Cp in type III latency and Qp in type I latency, as well as an increase in heterochromatic H3K9me3 at these sites. HCF1 depletion resulted in the loss of EBV episomes from Burkitt's lymphoma cells with type I latency and reactivation from lymphoblastoid cells (LCLs) with type III latency. These findings indicate that HCF1 and OCT2 function at OriP to regulate viral transcription, histone modifications, and episome maintenance. As HCF1 is best known for its function in herpes simplex virus 1 (HSV-1) immediate early gene transcription, our findings suggest that EBV latency transcription shares unexpected features with HSV gene regulation.IMPORTANCEEBV latency is associated with several human cancers. Viral latent cycle gene expression is regulated by the epigenetic control of the OriP enhancer region. Here, we show that cellular factors OCT2 and HCF1 bind OriP in association with EBNA1 to maintain elevated histone H3K4me3 and transcriptional enhancer function. HCF1 is known as a transcriptional coactivator of herpes simplex virus (HSV) immediate early (IE) transcription, suggesting that OriP enhancer shares aspects of HSV IE transcription control.

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