UAS regulatory sequences drive expression of a vesicle tethered form of spGFP1-10, in which it is fused to nSyb. This construct is designed for use in a GRASP (GFP Reconstitution Across Synaptic Partners) assay, in which complementary split fluorescent protein fragments expressed on the extracellular membrane of different neurons can reconstitute a functional fluorescent protein at points of contact between the neurons.