A recombinant murine retrovirus expressing v-rel is cytopathic

A murine retrovirus that expresses the avian v-rel oncogene was constructed. NIH 3T3 cells transfected with this construct expressed v-rel-specific RNA and a 59-kDa protein serologically identical to avian v-rel. The protein expressed from the recombinant retrovirus retained the associated protein kinase activity observed in avian systems. While the detection of v-rel RNA sequences in infected cells verified the infectivity of the retrovirus, the retrovirus did not transform either murine fibroblasts or bone marrow cells. Rather, a cytopathic effect was observed in murine fibroblasts and a pre-B lymphoid cell line that were infected with the murine retrovirus. Growth curves of these infected cells revealed cell death or diminished growth rate in all cases.