Tomography Studies of the Dengue Fusion Process

During dengue virus (DENV) infection, structural changes in the envelope (E) protein facilitate virus:endosomal membrane fusion. Crystal structures of E protein pre-fusion dimers and post-fusion trimers showed some of the structural information about the start- and end-stages of the fusion process. Here, we used cryo-electron tomography (cryo-ET) and biochemical assays to study the early events of the DENV fusion process. We characterized the interactions of DENV to liposomes at pH conditions that mimic that in the early to late endosomes. We also conducted tomography studies on the structural changes of DENV E proteins and identified an open E trimer fusion intermediate structure. Results offer new insights on the early fusion event of DENV.