Membrane-dependent uridylylation of the genome-linked protein VPg of poliovirus.

Abstract
A small nucleotidyl protein was synthesized in vitro in a membrane fraction of poliovirus-infected HeLa [human cervical carcinoma] cells. Analyses of the nucleotides and polypeptide showed that the nucleotidyl protein is VPg-pUpU, the genome-linked protein of poliovirion RNA covalently bound to the first 2 5''-terminal nucleotides of poliovirus RNA. Synthesis of VPg-pUpU in vitro was sensitive to nonionic detergent. Evidently, VPg-pUpU is part of the initiation complex in poliovirus RNA replication in a membranous environment.