The PI has recently found that virus-like shells can be assembled in vitro, using 14S pentameric subunits obtained from naturally-occuring empty capsids (i.e. procapsids). This system provides a basis for designing an in vitro reaction mixture capable of forming poliovirions. The main objective of this proposal is to establish such a reaction mixture and to use it as an assay to purify and isolate the viral-specific "morphopoietic" factor(s) present in Hela cells which is responsible for forming procapsids (and virus particles) from 14S material in vivo. Experiments will be conducted to: 1) identify its nature 2) ascertain its mode of action, and 3) quantitate the amount needed to support the in vitro virus assembly system. Two series of other experiments are also planned. The first is aimed at characterizing the nature of the interactions between the virions and monoclonal antibodies to different viral capsid epitopes. The second deals with the significance of the "internal" initiation site in polioviral RNA. The project as a whole will contribute substantially to our understanding of the way proteins of poliovirus and other picornaviruses are synthesized and processed.
