The 5' end of poliovirus mRNA is not capped with m7G(5')ppp(5')Np.

Abstract
Poliovirus was grown in HeLa cells in the presence of 32P and actinomycin D. At 3-4 h after infection, viral mRNA was recovered from polyribosomes and its identity verified by 2-dimensional gel electrophoresis of RNase [phage] T1 digests. Digestion of the viral [32P]mRNA with RNase [phage] T2 and separation of the products by ion exchange chromatography at pH 5 yielded pUp as possible 5'' terminus but no capping group of the structure m7G(5'')ppp(5'')Np. Total cytoplasmic [32P]RNA of HeLa cells contained capping groups. Neither the capping group nor ppNp or pppNp was found in an RNase T2 digest of poliovirion [32P]RNA. The data indicate that 5''-terminal m7G(5'')ppp(5'')Np is absent from poliovirus RNAs and therefore is not involved in poliovirus protein synthesis.