lexAop regulatory sequences drive expression of the spGFP1-10 split fluorescent protein fragment fused to the cytoplasmic domain of nSyb, thus targeting the protein to pre-synaptic sites. 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.