Function analysis of viral glycoprotein in viral infection

Ebola viruses are enveloped, nonsegmented, negative-stranded RNA viruses. Together with Marburg viruses, they are classified in the order of Mononegavirales and the family of Filoviridae. Ebola GP2 protein, which is a type I viral fusion protein, mediates virus-host membrane fusion. The role of the charged residues in the function of Ebola GP2 was evaluated by a HIV-based pseudotyping system. We found that several charged residues are important for GP2 function. In contrast a similar analysis of the charged residues of HIV-1 gp41 showed different effect from Ebola GP2, especially in C-helix. These results suggest that the charged residues of Ebola GP2 may participate in the formation of fusion-active GP2 conformation or play a role in GP2 intermediate status in fusion process. We also demonstrate that Ebola GP2 played an active role in virus release by characterizing a gain-of-function Ebola GP2 mutant. We showed the enhanced infectivity probably resulted from the newly acquired GP2 association with raft-like lipid microdomains during virus budding.