The 5'-terminus of poliovirion RNA consists of a protein covalently linked to the nucleotide sequence pU-U-A-A-A-A-C-A-G, which may act as a primer for initiating viral RNA synthesis.
The identification of a covalently linked protein at the 5'-terminus of poliovirus RNA provides foundational evidence that a protein-nucleotide structure acts as a primer for viral RNA synthesis.
The 5'-terminus of poliovirus polyribosomal RNA is pUp. A candidate for the 5'-terminus of poliovirion RNA was recovered as a compound migrating toward the cathode when 32P-labeled virion RNA was completely digested with ribonucleases T1, T2 and A and analyzed by paper ionophoresis at pH 3.5. Treatment with proteinase K reversed its direction of migration, indicating the presence of protein. Treatment with venom phosphodiesterase liberated all of the radioactivity as pUp, suggesting that poliovirion RNA has a protein-pUp 5'-terminus. Treatment of virion RNA with T1 ribonuclease alone generated a proteinase K-sensitive oligoribonucleotide. Analysis of the oligoribonucleotide using ribonucleases A and U2 showed its structure to be protein-pU-U-A-A-A-A-C-A-G. Digests of replicative intermediate RNA contained sufficient protein-pUp to suggest that this structure is at the 5'-end of most nascent poliovirus RNA molecules. We suggest that a protein-nucleotide structure acts as a primer for initiating synthesis of poliovirus RNA.
Flanegan et al. (Tue,) conducted a other in Poliovirus. Biochemical analysis of poliovirus RNA was evaluated on 5'-terminus structure of poliovirion RNA. The 5'-terminus of poliovirion RNA consists of a protein covalently linked to the nucleotide sequence pU-U-A-A-A-A-C-A-G, which may act as a primer for initiating viral RNA synthesis.