Figure 1 Structure of the PBV particle. (Left) Surface rendering from a three-dimensional reconstruction viewed down a slightly misoriented five-fold axis. Note the presence of 60 dimeric protrusions. (Middle) Diagram representing a triacontahedron, a convex polyhedron made of 30 rhombic faces or diamond tiles. (Right) Triacontahedral design of the particle, with each of the tiles formed by two CP dimers colored differently
(Courtesy of J. Lepault and S. Duquerroy for the left and right panels, respectively.)
Figure 2 Schematic representation of the gene arrangement in genome segments 1 and 2 of human picobirnavirus. Segment 1 possesses three ORFs. ORF3 encodes the CP precursor. Segment 2 encodes an RNA-dependent RNA polymerase (RdRp). Numbers indicate the positions and lengths of the ORFs.
Figure 3 Schematic representation of the gene arrangement in genome segment 1 of rabbit PBV and processing of the CP precursor. Numbers indicate the nucleotide the amino acid positions (the latter in bold type).
Figure 4 A distance tree representing the phylogenetic relationships among the RNA-dependent RNA polymerases (RdRps) from genetic clusters in the family. The tree was constructed using the software Mega4 and the NJ algorithm, with the option complete deletion, which ensures that only the positions represented in all sequences of the ClustalW multiple alignment were used for the tree calculation. Numbers indicate bootstrap percentages obtained for each node. Sequences are represented by their protein accession numbers. All derive from human picobirnavirus isolates except ACT64131, which corresponds to a bovine isolate. Two genogroups have been defined thus far on the basis of RdRp sequences. The prototype strains are HY005102 (YP_239361) and 1-CHN-97 (AAG53583) for genotype 1 and 4-GA-91 (AAG53584) for genotype 2.