Lymphotropic strain SL3 of Aleutian disease virus: identification of replicative form DNA, molecular cloning and expression of capsid-specific proteins.

Replicative form (RF) DNA of the lymphotropic strain SL3 of Aleutian disease virus was isolated from infected cell cultures. A novel intermediate of about 7.6 kilobases was demonstrated in Hirt lysates in addition to single-stranded viral, double-stranded monomer and dimer RF DNA. The monomer RF DNA exhibited a length heterogeneity of 70 bp and 160 bp at its 3' and 5' termini. The two major monomer RF DNA species each contained hairpins in the extended or the foldback configurations. A central fragment between map units 0.15 and 0.88 was cloned into plasmid pUC18. The recombinant clone expressed virus-specific proteins ranging from 32,000 to 74,000 mol. wt.