Figure 1 (Left) Diagram of virions of Poliovirus (PV). The surface shows proteins VP1, VP2 and VP3. The fourth capsid protein, VP4, is located about the internal surface of the pentameric apex of the icosahedron. (Right) Negative contrast electron micrograph of Poliovirus particles. The bar represents 100 nm.
Figure 2 (Top left) Particle of Poliovirus serotype 1 (PV-1). (Top right) Particle of Human rhinovirus B serotype 14 (HRV-14). (Bottom left) Particle of Encephalomyocarditis virus (EMCV). (Bottom right) Particle of Foot-and-mouth disease virus serotype O (FMDV-O). The bar represents 10 nm. (Courtesy of J.-Y. Sgro, with permission.)
Figure 3 Genome structure and gene organization of members of the family Picornaviridae. The filled oval at the 5-end is the genome-linked protein VPg (also referred to as the 3B gene product) followed by the 5-non-translated region (5-NTR; line). Letters (Cn) above the 5-NTR depict poly(C) tracts that are present in some viruses. The 1A gene products are myristylated at the amino terminal glycine, although the situation for hepatoviruses is not known. The open boxes depict the long ORF encoding the polyprotein that is followed by the 3-non-translated region (line) and a poly(A) tract (An). The eventual cleavage products of the polyprotein are indicated by vertical lines in the boxes, the nomenclature of the polypeptides follows an L:4:3:4 scheme corresponding to the genes (numbers) encoded by the L, P1, P2, P3 regions. (Rueckert and Wimmer, 1984.) The P1 region encodes the structural proteins 1A, 1B, 1C and 1D, usually referred to as VP4, VP2, VP3 and VP1, respectively. VP0, not shown here, is the intermediate precursor for VP4 and VP2. In all viruses 3C is a protease, in enteroviruses and rhinoviruses 2A is a protease, while in all viruses 3D is considered to be a component of the RNA replicase. Only Foot-and-mouth disease virus encodes 3 VPg proteins that map in tandem.
Figure 4 Phylogenetic trees showing the relationships between the species and genera of the family Picornaviridae. (a) Proetin P1 and (b) Protein 2C+3CD. The Neighbor-joining trees were produced and bootstrapped (1000 replicates) using CLUSTALX and an amino acid weight matrix (BLOSUM). The tree was drawn using TreeView v1.5.2
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