Study On The Molecular Mechanisms Of The Epigenetic Regulation During Epstein-Barr Virus Reactivation From Latency

DNA demethylation plays an important role in the reactivation of Epstein-Barr virus (EBV) from latency infection to lytic infection. However, it is until unknown that how the first step of epigenetic modification change (especially DNA demethylation) is initiated in response to external stimulation. In our study, we verify that Erk/c-Jun signaling pathway is essencial for the DNA demethylation of Zta gene (an EBV immediate early gene) in responding to TPA (12-O-Tetradecanoyl Phorbol-13-Acetate) stimulus. Markedly, phosphorylation of c-Jun facilitates the DNA demethylation of Zta promoter, whereas c-Jun knockdown represses Zta demethylation in responding to TPA stimulation. Furthermore, we verified that c-Jun interplays with the Tetl DNA dioxygenase through yeast two-hybrid, GST pulldown, Co-IP and immunofluorescence methods for the first time. ChIP results showed that c-Jun recruits Tetl to Zta promoter. The binding of Tetl to Zta promotes its promoter demethylation by oxidizing 5mC into 5hmC. RNA interference of Tetl inhibits TPA-stimulated Zta demethylation and expression. In conclusion, TPA activates Erk/c-Jun signaling pathway, which subsequently recruits Tetl to Zta promoter to enhance DNA demethylation and the expression of Zta, then the expression of lytic early genes (such as BHRF1) and lytic late genes (such as gp350/220), and finally the stimulation of EBV reactivation. This research reveals essential roles of Erk/c-Jun signaling pathway and Tetl in the regulation of epigenetic modification, and provides new insights into the mechanism underlying the regulation of virus latent and lytic infection.