Abstract
Virion RNA (vRNA) from poliovirus type 1 (PV1), poliovirus type 2 (PV2) and coxsackie virus B1 (Cox B1) were treated with proteinase K to remove all but a small peptide of the covalently attached 5'' genome-linked virion protein (VPg). The peptide on these RNA molecules was then treated with Bolton-Hunter 125I reagent, which iodinates primary amine groups, to obtain specific 5''-terminal radioactive labeling. Sequences of 125I-labeled vRNA were determined by using a set of base-specific RNases and a partial alkaline hydrolysis ladder. The 1st 20 positions of these RNA show a remarkable conservation of sequence. The initial 10 nucleotides are identical in PV1, PV2 and Cox B1, with the sequence VPg-pU-U-A-A-A-A-C-A-G-C-. The next 10 nucleotides show a one-base difference between PV1 and PV2 and 50% homology between PV1 and Cox B1. This conserved 5'' region may provide a recognition site for interaction between the viral mRNA and the host translation system.