Transfection of Fv-1 permissive and restrictive mouse cells with integrated DNA of murine leukemia viruses.

Whole-cell DNA preparations isolated from SC-1 cells chronically infected with N- or B-tropic murine leukemia viruses (MuLV) were tested for infectious activity in an Fv-1n (NIH-3T3) and two Fv-Ib (C57BL/6 and SV-A31) cell cultures. Efficiency of transfection for all DNAs was better in the NIH-3T3 cells than in C57BL/6 or SV-A31 cells; and an [N-tropic MuLV]SC-1 cell DNA preparation was slightly more infectious than a [B-tropic MuLV]SC-1 cell DNA preparation in all three cell cultures, regardless of their Fv-1 genotypes. Progeny viruses from the transfection showed N- or B-tropism corresponding to that of the parent viruses produced by the infected SC-1 cells that were used for the DNA preparation. DNA dose-response studies in NIH-3T3 cells revealed a one-hit mechanism for both the [B-tropic MuLV]SC-1 cell DNA and the [N-tropic MuLV]SC-1 cell DNA preparation. These results demonstrate that, in contrast to virion infection, transfection of N- and B-tropic MuLV with DNA preparations from chronically infected cells is not affected by the Fv-1 gene.