Restriction endonuclease mapping of the frog virus 3 genome

A physical map for the frog virus 3 (FV 3) genome was constructed after digestion with the following restriction endonucleases: EcoRI, HindIII, KpnI, and XbaI. Mapping of the DNA was accomplished by partial digestion and recutting, double-digestion, and Southern blot hybridization with deduction of overlaps. Although the virion DNA is physically linear, the restriction map was circular, supporting the data that the FV 3 genome is circularly permuted (Goorha and Murti, Proc. Nat. Acad. Sci USA 79, 248-252, 1982), a unique feature among eukaryotic viruses.