Fig. 9. Effects of laminin are dependent on Rac 1. Cells growing on a polyamine substrate were injected with either vehicle (veh.), wild-type Rac 1 (wt) or dominant-negative Rac 1 (N17). After determining which cells were alive and labeled, CD was added to the cultures for 15 minutes followed by treatment with laminin for 1 hour. CD was then washed out of the cultures and further observations made after 1 hour. (A) 25 minutes after the addition of laminin, F-actin foci have formed in cells injected with wt Rac 1 but typically not in cells injected with N17 Rac 1. (B) 1 hour after the addition of laminin, N17 Rac 1 has also inhibited neurite outgrowth. (C) After washout of CD, N17 Rac 1 continues to inhibit outgrowth compared to the wt control.