Giant Drosophila neurons differentiated from cytokinesis-arrested embryonic neuroblasts.

The relative contributions of the intrinsic and extrinsic factors in determining neuronal differentiation are not fully understood yet. We found that isolated neuroblasts from Drosophila gastrulae were able to differentiate neuron-specific properties in culture even when cell divisions were inhibited. The resultant giant multinucleated neurons displayed thickened neurites with a variety of distinct branching patterns. Neuronal antigens were expressed as in normal cultured neurons, and action potentials could be evoked by current injection within two days after plating. These results indicate that the factors for initiating specific differentiation programs for basic neuronal form and function are present in a neuroblast already. The cells of increased sizes in this culture system are more accessible to physiological and cell biological analyses and could facilitate future studies of the Drosophila nervous system.