A repertoire of pre- and postsynaptic markers for studying synaptic organization in Drosophila. a) Electron micrograph of an ORN axon terminal. The Drosophila AZ is readily identified by an electron-dense T-bar structure that is composed of a Brp-rich table-top (red arrowhead) and an RBP-rich pedestal (red arrow). The T-bar is surrounded by synaptic vesicles (green arrowhead) and abuts the synaptic cleft (yellow bracket). b) Cartoon schematic of Drosophila synapse. Synaptic proteins accumulate in distinct subcellular compartments at the synapse. Synaptic markers for visualization are generally recombinant proteins consisting of the full-length protein sequence of a synaptic protein (or an interacting portion of that protein) fused to a fluorescent protein or epitope tag. The resultant product can then be followed in one specific cell or set of cells using inducible expression strategies and imaged using commercially available antibodies to the epitope or fluorescent tags with immunohistochemistry or live imaging. A selection of published pre- (top) and postsynaptic (bottom) labels are based on the proteins highlighted (Right; color coding reflects their general location at the synapse as diagrammed).