Final Envelopement of Epstein-Barr Virion

Epstein-Barr vrius (EBV) infects B lymphocyte and epithelial cells. The infections are commonly persistent and latent. However, the virus must go through a lytic stage to produce progenies to establish new infections. During the lytic cycle, large amounts of viral DNA and proteins are produced, then DNA is packaged into capsid in the nucleus. Viral glycoprotein- embedded envelope then adds onto the nucleocapsid during maturation: including processes of primary envelopment, de-envelopment and final envelopment. Our earlier study showed BBLF1 involves in final envelopment. However, exact how the protein influences the process is unclear. My recent study identifies that viral BGLF2, a tegument protein associated with capsids, interacts with BBLF1, and the interaction promotes cytosolic BGLF2 translocation to the TGN membrane, where BBLF1 and viral glycoproteins are present. Therefore, this study posits that BBLF1 acts as bridge by interacting with BGLF2 and glycoproteins, thus recruiting BGLF2-coated capsids to glycoprotein-embedded TGN membrane. Ultimately, the interactions among BBLF1, BGLF2, and glycoprotein on TGN membrane promote the budding of capsids into lumen. Therefore, this project will investigate the interactions among BBLF1, BGLF2 and glycoproteins and how the interaction influence maturation. BBLF1 is dual-acylated modified protein located at the TGN and most likely on the lipid raft, suggesting that lipid rafts may serve as a platform during final envelopment. The relationship between lipid rafts and final envelopment and the mechanism of glycoprotein targeting to TGN or lipid raft will be investigated. Additionally, our study observed the number of autophagosome is increased during EBV lytic cycle, and EBV glycoprotein gp350/220 colocalizes with an autophagosomal marker, GFP-LC3. Using Atg5 siRNA to attenuate cellular autophagic activity lead to a reduction in virus particles, but enhancement in virion infectivity. Since the glycoproteins on virion in quantity and quality are crucial for EBV infection, This study will investigate how autophagy affect packaging of glycoprotein during final envelopment, which will affect virion infectivity. The results from study will provide a better understanding in final envelopment during EBV lytic cycle.

Project ID:PC10308-1890
External Project ID:MOST103-2320-B182-013