Antibody to poliovirus genome-linked protein (VPg) precipitates in vitro synthesized RNA attached to VPg-precursor polypeptide(s).

Antibody to poliovirus genome-linked protein VPg, specifically precipitated RNA synthesized in vitro by the poliovirus replicase and host factor in response to poliovirion RNA. A significant amount of the immunoprecipitated RNA was RNAase T1 resistant, sedimented at approximately 2-4 S and was shown to be largely polyuridylic acid. RNAase A digestion or alkali hydrolysis of the immunoprecipitated RNA left [32P]UMP-labeled material which comigrated on SDS-polyacrylamide gels with known VPg-precursor polypeptides. The results presented in this paper suggested that VPg was involved in the host factor-dependent, poliovirus replicase-catalyzed in vitro RNA synthesis, most probably in the form of a larger precursor protein.