Expression and function of tap in the gustatory and olfactory organs of Drosophila.

We have recently described the identification of a gene, tap, which encodes a bHLH protein expressed in one neuron of each larval chemosensory organ. Here we show that tap is expressed at a late stage in the development of one type of adult chemosensory organ, the gustatory bristles of the leg, wing and proboscis. We also show that tap is expressed very early in the development of a second type of chemosensory receptors, the olfactory organs of the antenna. The results of behavioral experiments suggest that the ectopic expression of tap affects the response to sugar and salt.