Characterization, molecular cloning, and physical mapping of the Shope fibroma virus genome

Five strains of Shope fibroma virus (SFV), a strain of rabbit myxoma virus, and a strain of vaccinia virus were compared by restriction endonuclease digestion of their viral DNAs. Restriction digest patterns revealed that SFV and rabbit myxoma, both members of the Leporipoxvirus genus, were distinct from vaccinia, an Orthopoxvirus. All strains of SFV examined had a high degree of nucleotide sequence homology as shown by conservation of restriction sites within their genomes. However, restriction patterns of SFV and myxoma were quite different from one another suggesting that the genomes from these two viruses of the Leporipoxvirus genus do not share a large, highly conserved region of homology as do the viruses belonging to the Orthopoxvirus genus. Restriction mapping identified inverted terminal repeats of approximately 12 kb in length. Restriction fragments representing all but 400 bp of the termini were cloned in plasmid vectors.