The hamster polyomavirus transforming properties.

The hamster papovavirus (HaPV) is a polyomavirus isolated from hair follicle tumor arising spontaneously in newborn hamsters which can also induce lymphoma and leukemia. This tissue specificity displayed in vivo can be bypassed in vitro since HaPV carries the full transforming properties of a polyomavirus (immortalization and transformation). We report here the phenotypic characterization of cells that were selected as immortalized or transformed and express constitutively the HaPV early genes. The viral genome is integrated in the host DNA and the early region is actively transcribed and translated.