Fig. 5.

Ectopic expression of Nex1 promotes the neurite regeneration of NGF-differentiated cells in the absence of an NGF boost. PC12 cells and PC12–Nex1-M(B) cells were differentiated for 7 days in the presence of NGF (50 ng/ml), after which the cells were thoroughly washed with NGF-free medium. The neurites were mechanically sheared as described in Materials and Methods. The cells were replated on collagen I-coated plates in the absence or presence of NGF (50 ng/ml). The regeneration process was analyzed 5 hr after replating. A: PC12–Nex1-M(B) cells display substantial neurite regeneration in the absence of NGF compared to PC12 cells. B: Ectopic expression of Nex1 enhances the propensity to initiate neurite outgrowth even in the absence or presence of NGF. The percentage of neurite-bearing cells was scored on at least 300 cells from three distinct experiments. Cells cultured in the absence of NGF after trituration are indicated by open bars, whereas cells grown in the presence of NGF after trituration are represented by hatched bars. This is a representative graph from a triplicate experiment that was repeated four times. The error is the standard deviation of the mean.