FIG. 1.

Full-length SDV cDNA construct. Three cDNA fragments (fragments 1 to 3) covering the entire SDV genome were assembled by ligation into the multiple cloning site of the pBluescript plasmid using the EcoRI, SmaI, XbaI, and NotI restriction enzyme sites, yielding the pBS-SDV construct. An XbaI restriction enzyme site has been introduced into the junction region by changing 2 nucleotides (underlined) as indicated in the sequences in the box. The top and bottom sequences in the box are the wild-type and modified SDV sequences, respectively. Differences observed in comparison to the previously published sequences (18, 21) are indicated by letters (a to x) on the pBS-SDV construct. Nucleotide positions and amino acid changes are indicated in Table 2.