Molecular signaling in a variant PC12 cell line (PC12-N1) that spontaneously extends neuronal processes

Neuritogenesis is a key event in the development of the nervous system. The rat pheochromocytoma PC12 cell line has been a useful model for studying neuriogenesis. When exposed to nerve growth factor (NGF), the PC12 cells extend neurites and differentiate into sympathetic neuron-like cells. We have isolated a variant PC12 subclone, PC12-N1, which spontaneously forms neurites and has increased sensitivity to NGF. We show that N1 cells express many neuronal specific proteins, and that a number of neuronal function-related genes are upregulated in N1 cells revealed by DNA microarray analysis. By manipulating culture conditions, we show that N1 cells display three distinct stages of neuritogenesis consisting of neurite initiation, rapid neurite elongation, and a maturation process characterized by extensive neurite branching, thickening of neurites, and increase in cell soma sizes. We demonstrate that while ERK signaling is involved in all aspects of neuritogenesis, JNK signaling is essential in the later stages. Additionally, we show a biphasic pattern of JNK activation induced by NGF in N1 cells, which is critical for NGF-mediated neuritogenesis. Taken together, this study has established an appealing cell model system for studying neuritogenesis and neuronal differentiation.*; *This dissertation is multimedia (contains text and other applications not available in printed format). The CD requires the following system requirements: Adobe Acrobat.