English: FMDV 5ʹ-UTR provides structural basis for initiation of viral protein translation. a Schematic representation of the structural elements within the FMDV 5ʹ-UTR. The 5ʹ-UTR is highly structured and comprises S-fragment, poly(C) tract, 3B-uridylylation site (bus) or cis-acting replication element (cre), pseudoknots (PKs), and internal ribosome entry site (IRES). The organization of the IRES element in different domains (I, II, III, IV, and V) is indicated. Domain I (the first 20 nt of the IRES) belongs to the right arm of bus. The conserved AAACA, GNRA, RAAA motifs, C-rich loop and polypyrimidine tracts are also indicated. The two different initiator codons AUG1 and AUG2 are separated by 84 nt. Note that the stems indicated are not perfectly base-paired.