Localization of gene functions in polyoma virus DNA

Polyoma virus mutants of four functionally distinct groups have been mapped by the marker rescue technique using restriction enzyme fragments of wild-type viral DNA. Nontransforming host-range mutants map in the proximal part of the early region of the viral genome. The same DNA fragment that restores a normal host range also restores normal transforming ability to these mutants. ts-25D, a temperature-sensitive (ts)-a class mutant, maps in the distal part of the early region. ts-3 and ts-1260 map in the proximal and distal parts of the late region, respectively.