Abstract: | Cotransfection of a transformation-deficient and immortalization-positive SV40 early gene mutant with various constructs of viral promoter-linked myc genes induced dense foci in 3Y1 cells, an established cell line derived from rat embryo fibroblasts, whereas transfections with either species alone did not. Four cell clones were isolated from colonies grown in soft agar medium, and found to contain at least a single copy of both DNA species and to express both sequences at relatively high levels. These results indicate that the two immortalizing genes used in the present study collaborate to transform 3Y1 cells. |