Fig. 8. Suppression of dbcAMP-induced neurite outgrowth in PC12 cells and serum-starvation-induced neurite outgrowth in N1E-115 cells by dominant-negative mutants of Cdc42, Tc10 and RhoT. PC12 and N1E-115 cells were transfected with the cDNA of Cdc42(T17N), Tc10(T23K) or RhoT(T35N) in pEF-BOS/Myc vector or with empty pEGFP-C1 vector (mock). Ten hours after the transfection, PC12 cells were treated with 0.5 mM dbcAMP and the N1E-115 cells were shifted to 0.5% FBS. They were stained with Myc1-9E10 48 hours after the treatment. (A,B) PC12 (A) and N1E-115 (B) cells mock-transfected (a,b) or transfected with Cdc42(T17N) (c,d), Tc10(T23K) (e,f) or RhoT(T35N) (g,h). Shown are phase-contrast (a,c,e,g) and Myc1-9E10-stained fluorescent (b,d,f,h) micrographs. Note that the cells with no expression of these mutants extend neurites. Bar, 20 µm. (C,D) Ratio of the neurite-extending PC12 (C) and N1E-115 (D) cells. The degree of neurite extension is expressed by multiples of the cell body diameter as indicated in the legend. More than 100 cells were assessed in each experiment. The values are the means±s.d. of triplicate experiments.