Neurite outgrowth in PC12 cells deficient in GAP-43.

The neuronal cell line PC12 undergoes a well-documented morphological and biochemical differentiation when treated with NGF and other growth factors. A hallmark of this growth factor-mediated differentiation is the induction of the growth-associated protein, GAP-43. Here we show that a PC12 cell line which is capable of NGF-, bFGF-, and cAMP-mediated neurite outgrowth is deficient in GAP-43 protein and full-length mRNA, as measured by immunocytochemistry, Western blot, Northern blot, and PCR analyses, respectively. We propose that the GAP-43 protein may not be essential for the initial extension and maintenance of neurites induced by these neuritogenic factors; rather, its role may lie predominantly in growth cone function and in the operation of the presynaptic terminal.