Figure 4.

Effect of dominant-negative Ras on transformation by a threshold dose of v-Src. (A) Expression of Src and Ras in untransfected Rat-2 and MS1 cells, MS1 cells stably transfected with the empty expression vector (MS1/pcDNA3), and three independent clones transfected with the N17Ras expression construct (MS1/N17Ras-1, -2, and -3). (B) Soft agar colony assays were performed with the cell lines described in A. Colonies were stained with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) 16 days after plating.