The assembly of virions. The virion consists of a nucleocapsid composed of a single protein species and the genomic RNA surrounded by a lipid bilayer containing two integral membrane glycoproteins encoded by the virus. In contrast to other enveloped viruses, alphaviruses have a precise icosahedral structure. Using genetic and structural approaches we are investigating how this structure is assembled. The nature of the receptors used by the virus to enter cells.
Alphaviruses can infect many different organisms.
The evolution and ecology of the alphaviruses also present interesting problems. Eastern equine encephalitis virus and a New World relative of Sindbis virus, an Old World alphavirus. We believe that alphaviruses arose in the New World and were subsequently carried to the Old World in two waves. One Old World introduction founded the group composed of Semliki Forest virus and its close relatives, and the other Old World introduction distributed the Sindbis-like viruses around the world. Our data suggest that this transfer occurred within the last 1000-2000 years, and we suggest that this relatively recent spread was accomplished by migratory birds.