Molecular genetic identification of a candidate receptor gene for sweet taste.

A cDNA clone encoding a novel member of the putative taste receptor T1R family, designated T1R3, was isolated from circumvallate papillae of the mouse tongue using degenerate primers. Reverse transcription-polymerase chain reaction analysis showed predominant expression of the receptor in circumvallate papillae. In situ hybridization analysis revealed that T1R3 was expressed in a subset of taste receptor cells in taste buds and that the topographic distribution of T1R3 in various taste papillae was different from those of the other T1R members. Genetic mapping of T1R3 with a mouse/hamster radiation hybrid panel located the gene on the distal end of mouse chromosome 4 correlated with the Sac locus affecting sweet sensitivity of mice. Our results indicate that T1R3 may serve as the receptor for sweet perception in mice. Copyright 2001 Academic Press.