Growth cone behavior underlying the development of stereotypic synaptic connections in Drosophila embryos

摘要: Each muscle fiber in the segmented body wall of Drosophila larvae is innervated by anatomically stereotyped neuromuscular junctions. These synapses arise through selective choices motoneuronal growth cones at their peripheral targets. Using digital optical microscopy staged intracellular dye fills, we have singly identified embryonic motoneurons and examined individual when they contact differentiate target cells. There a precise connectivity between motoneuron fiber, which direct consequence cone behavior. We also found that fibers possess molecularly heterogeneous cell surfaces may be involved recognition appropriate Fasciclin III, homophilic adhesion molecule, coexpressed several efferent site-specific fashion fiber's membrane. The fasciclin III expression transient, corresponding to period embryogenesis first contacts are made. Upon encountering surface, can sprout stereotypically arrayed filopodial processes, orient along anterior-posterior axis, turn predictable directions. Subsequently, terminal branches established nonrandom order. phenomena were occur two innervate adjacent targets, general features synaptogenesis Drosophila.