A monoclonal antibody, mAb 44D5, has been used to identify and clone Drosophila syntaxin 1 (Dsynt1), an homologue of rat syntaxin 1. The deduced amino acid sequence of the Dsynt1 cDNA cloned is highly homologous to rat syntaxin 1A. Dsynt1 contains 291 amino acid residues and like other members of the syntaxin family is an integral membrane protein, with a transmembrane region at its carboxy-terminus and several regions of the molecule predicted to be in a coiled-coil conformation. The protein is specific to the nervous system and localized in synaptic areas of both central nervous system (CNS) and neuromuscular junction. The same antibody used to clone Dsynt1 cDNA stains synaptic areas in rat cerebellum and a neurospecific antigen in rat and human tissues with identical relative mobility to rat syntaxin 1.