In vitro pattern formation during neurogenesis in neuroectodermal progenitor cells immortalized by p53-deficiency.

In vitro neural differentiation was induced in a p53-deficient immortalized neuroectodermal progenitor cell line, NE-4C, by treatment with retinoic acid [K. Schlett and E. Madarász (1997) J. Neurosci. Res. 47, 405-416]. Rearrangement of nestin filaments was an early marker of neuron-formation. The increase in neurofilament protein content was accompanied by a decrease in the expression of nestin filaments in induced precursors. Cells with astroglial features appeared with a delay of 4-5 days compared to the appearence of neurons. Future neurons were sorted out from the substrate-attached population of apparently non-induced cells. The sorting out of future neurons resembled the separation of neural precursors in vivo. The continuous changes in the shape and also in the position of the cells resulted in the formation of characteristic morphological patterns. On the basis of morphological changes, five characteristic stages of in vitro neural differentiation were distinguished. The analysis of the morphological changes revealed that cell-to-cell interactions played an essential role in the cell fate decision made by induced precursors. Our observations indicate that the NE-4C cell line can serve as an in vitro model to investigate some early steps of neurogenesis.