Functional analysis of an olfactory receptor in Drosophila melanogaster.

Fifty nine candidate olfactory receptor (Or) genes have recently been identified in Drosophila melanogaster, one of which is Or43a. In wild-type flies, Or43a is expressed at the distal edge of the third antennal segment in about 15 Or neurons. To identify ligands for the receptor we used the Gal4/UAS system to misexpress Or43a in the third antennal segment. Or43a mRNA expression in the antenna of transformed and wild-type flies was visualized by in situ hybridization with a digoxigenin-labeled probe. Electroantennogram recordings from transformed and wild-type flies were used to identify cyclohexanol, cyclohexanone, benzaldehyde, and benzyl alcohol as ligands for the Or43a. This in vivo analysis reveals functional properties of one member of the recently isolated Or family in Drosophila and will provide further insight into our understanding of olfactory coding.