Analysis of the Drosophila Sugar Receptor Genes

Gustation, also known as taste perception, is critical for the survival of most animal species. The fruit fly Drosophila melanogaster employs 68 different gustatory receptors (GRs) for the detection of sugars, bitter or toxic compounds, and pheromones. However, with a few notable exceptions, the functions of most GRs involved in feeding are unknown. Our research has focused on a cluster of highly-related Drosophila Grs, known as the Gr64 family, that have been shown to be critical for the perception of multiple sugars. Furthermore, we have demonstrated that another gene related to the Gr64 genes, Gr61a, is a sugar receptor that is narrowly tuned to a subset of pyranose sugars and may (along with the Gr64 genes) be indispensable for early fly development.

As a complementary approach to our behavioral analysis, we have examined the expression pattern of the Drosophila sugar receptors using knock-in driver alleles created by homologous recombination. As expected, most of these drivers have shown strong expression in various taste tissues. Intriguingly, some of these knock-in alleles also show expression in the maxillary palp and antenna, tissues previously thought to be involved only in olfaction. These expression patterns raise interesting questions about the true range of function of these chemosensory receptors and whether or not they might be involved in olfaction as well as gustation.