A family of candidate taste receptors in human and mouse

The gustatory system of mammals can sense four basic taste qualities, bitter, sweet, salty and sour, as well as umami, the taste of glutamate1,2,3,4,5,6. Previous studies suggested that the detection of bitter and sweet tastants by taste receptor cells in the mouth is likely to involve G-protein-coupled receptors2,7,8. Although two putative G-protein-coupled bitter/sweet taste receptors have been identified9, the chemical diversity of bitter and sweet compounds leads one to expect that there is a larger number of different receptors8,10,11. Here we report the identification of a family of candidate taste receptors (the TRBs) that are members of the G-protein-coupled receptor superfamily and that are specifically expressed by taste receptor cells. A cluster of genes encoding human TRBs is located adjacent to a Prp gene locus12, which in mouse is tightly linked to the SOA genetic locus that is involved in detecting the bitter compound sucrose octaacetate13,14,15. Another TRB gene is found on a human contig assigned to chromosome 5p15, the location of a genetic locus (PROP) that controls the detection of the bitter compound 6-n-propyl-2-thiouracil in humans16,17.