Fig. 1.

The structure of enterovirus 71 genome and virion organization. The RNA genome of EV-A71 is approximately 7.4 kb, with an untranslated region (UTR) at the 5′ and 3′ ends of the genome. The 5′UTR contains an internal ribosomal entry site (IRES) for cap-independent translation. The 5′UTR is bound covalently to VPg (3B), and the 3′UTR includes a poly-A tail. The RNA is translated to a polyprotein that is sequentially cleaved by the viral 2A protease (2Apro), 3CD protease, and 3C protease (3Cpro).