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    Please use this identifier to cite or link to this item: http://ir.nhri.org.tw/handle/3990099045/10518


    Title: Epstein-Barr Virus Rta-mediated accumulation of DNA methylation interferes with CTCF binding in both host and viral genomes
    Authors: Chen, YJ;Chen, YL;Chang, Y;Wu, CC;Ko, YC;Tsao, SW;Chen, JY;Lin, SF
    Contributors: National Institute of Cancer Research;Division of Infectious Diseases
    Abstract: Rta, an Epstein-Barr virus (EBV) immediate-early protein, reactivates viral lytic replication that is closely associated with tumorigenesis. In previous studies, we demonstrated that in epithelial cells Rta efficiently induced cellular senescence, which is an irreversible G1 arrest likely to provide a favorable environment for productive replications of EBV and Kaposi's sarcoma-associated herpesvirus (KSHV). To restrict progression of the cell cycle, Rta simultaneously upregulates CDK inhibitors and downregulates MYC, CCND1 and JUN, among others. Rta has long been known as a potent transcriptional activator, thus its role in gene repression is unexpected. In silico analysis revealed that the promoter regions of MYC, CCND1 and JUN are common in: (1) presence of CpG islands, (2) strong ChIP signals of CCCTC-binding factor (CTCF), (3) at least one Rta binding site is found. By combining ChIP assays and DNA methylation analysis, here we provide evidence showing that Rta binding accumulated CpG methylation and decreased CTCF occupancy in the regulatory regions of MYC, CCND1 and JUN, which were associated with downregulated gene expression. Stable residence of CTCF in the viral latency and reactivation control regions is a hallmark of viral latency. Here, we observed that Rta-mediated decreased binding of CTCF in the viral genome is concurrent with virus reactivation. Thereby, via interfering with CTCF binding, in the host genome Rta can function as a transcriptional repressor for gene silencing, while in the viral genome Rta acts as an activator for lytic gene loci by removing a topological constraint established by CTCF.IMPORTANCE CTCF is a multifunctional protein that variously participates in gene expression and higher-order chromatin structure of the cellular and viral genomes. In certain loci of the genome, CTCF occupancy and DNA methylation are mutually exclusive. Here, we demonstrate that the Epstein-Barr virus (EBV) immediate-early protein, Rta, known to be a transcriptional activator, can also function as a transcriptional repressor. Via enriching CpG methylation and decreasing CTCF reloading, Rta binding efficiently shut down the expression of MYC, CCND1, and JUN, thus impeding cell cycle progression. Rta-mediated disruption of CTCF binding was also detected in the latency/reactivation control regions of the EBV genome, and this in turn led to viral lytic cycle progression. As emerging evidence indicates that a methylated EBV genome is a preferable substrate for EBV Zta, the other immediate-early protein, our results suggest a mechanistic link in understanding the molecular processes of viral latent-lytic switch.
    Date: 2017-08
    Relation: Journal of Virology. 2017 Aug;91(15):Article number e00736-17.
    Link to: http://dx.doi.org/10.1128/jvi.00736-17
    JIF/Ranking 2023: http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=NHRI&SrcApp=NHRI_IR&KeyISSN=0022-538X&DestApp=IC2JCR
    Cited Times(WOS): https://www.webofscience.com/wos/woscc/full-record/WOS:000405866600036
    Cited Times(Scopus): https://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=85023201003
    Appears in Collections:[林素芳] 期刊論文
    [陳振陽] 期刊論文
    [張堯] 期刊論文

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