Fig. 2. RacV12 alleviates the G1 block induced by Abl-PP-K^–. (A) RacV12 rescues the G1 block induced by Abl-PP-K^–. Quiescent NIH3T3 transfected with the indicated constructs were stimulated or not with PDGF or 10% fetal calf serum as indicated for 18 hours in the presence of BrdU. (B) RacV12 does not rescue the G1 block induced by dominant interfering mutants of Shc and Stat3. Quiescent NIH3T3 transfected with the indicated constructs were stimulated or not with PDGF and proceeded as in A. Cells were fixed and stained for BrdU incorporation and ectopic protein expression as described in Materials and Methods. The mean±s.d. of the percentage of BrdU-positive cells present in expressing and non-expressing cells under the specified conditions is shown.