Candidate taste receptors in Drosophila

Little is known about the molecular mechanisms of taste perception in anima ls, particularly the initial events of taste signaling. A large and diverse family of seven transmembrane domain proteins was identified from the Dros ophila genome database with a computer algorithm that identifies proteins o n the basis of structure. Eighteen of 19 genes examined were expressed in t he Drosophila labellum, a gustatory organ of the proboscis. Expression was not detected in a variety of other tissues. The genes were not expressed in the labellum of a Drosophila mutant, pox-neuro(70), in which taste neurons are eliminated. Tissue specificity of expression of these genes, along wit h their structural similarity, supports the possibility that the family enc odes a Large and divergent family of taste receptors.