Integration and Expression of Mcf-13 Provirus in Mcf-13-Induced Lymphomas

Polytropic viruses were isolated from 11 MCF-13-induced lymphomas using multiple infectious cycles on the mink lung and SC1 cell lines. The viruses were characterized by host range infectious properties and by biochemical properties using Cleveland's polypeptide mapping of the p30 and gp 70 viral proteins demonstrating identity in their biological properties with the MCF-13 lymphoma-inducing virus. Restriction enzyme analysis of the high molecular weight tumoral DNAs confirmed the presence of proviral sequences homologous to the inducing provirus in the lymphoma genomes indicating that MCF-13 MuLV has integrated in the cellular genome of the induced lymphomas.