Figure 1 (Left) Canine parvovirus (CPV) capsid structure using a space-filling model, where each amino acid is represented by a 4Å sphere. One VP2 molecule is shown using darker spheres to illustrate the contribution of each VP2 protein to the structure and the intertwined arms of the VP2 molecules. (Right) Negative contrast electron micrograph of CPV particles. The bar represents 100 nm. (Courtesy of C.R. Parrish).
Figure 2 Gene organization and schemes of transcription are shown for Adeno-associated virus (AAV), Mice minute virus (MMV) and B19 virus (B19V). Genes are shown as boxes. The left ends of the mRNAs (thick lines) are the sites of the mRNA caps (filled circles), the right ends are the polyadenylation sites (arrows); introns are indicated by thin lines. (Adapted from Berns, 1990.)
Figure 3 The genetic organization of (top) the invertebrate Junonia coenia densovirus (JcDNV, Densovirus), and (bottom) Aedes albopictus densovirus (AlDNV, Brevidensovirus). S, structural proteins; NS, non-structural proteins; I, IV, VI are open reading frames. The arrowed lines indicate the possible transcription products that have been deduced from DNA sequence analyses.
Figure 4 DNA replication model for Adeno-associated virus (AAV). The terminal repeats of AAV are self-complementary and capable of forming hairpins shown in structure II. This allows for self-primed DNA synthesis from the 3 hydroxyl group. The site and strand specific nick shown in IV is made by Rep 68 or Rep 78. The two large Rep proteins also possess helicase activity, as required for the isomerization to convert structure V to VI. Structures VII and VIII are equivalent to structures II and III. Structure VII can either be encapsidated during strand displacement (resulting in net virion production) or it can enter the template amplification pathway as shown.
Figure 5 The phylogenetic relationships among the various members of the family Parvoviridae, determined by comparison of a conserved region of about 220 residues from the Rep and NS1 proteins, equivalent to the sequence between residues 254 and 562 of the NS1 protein of Mice minute virus (MMV). The sequences were aligned using the Clustal algorithim of the DNAStar program, and the most parsimonious phylogenetic relationships were determined using the Branch and Bound algorithim of the program PAUP (version 3.1.1). Thirty minimal phylogenies were derived, which all had the same overall topology, but which differed in arrangements of closely related sequences within some clades. The phylogeny shown is not rooted, and the branch lengths are proportional to the number of differences between sequences. (Contributed by Dr. Colin Parrish.)
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