The saccharin preference locus (Sac) and the putative sweet taste receptor (TR1) gene have distinct locations on mouse chromosome 4

摘要

A putative sweet taste receptor, TRl, has been recently cloned and the TRi gene has been mapped to mouse distal chromosome 4 (Hoon et at., 1999). The Sac (saccharin preference) locus affecting mouse behavioral and neural responsiveness to sweeteners has also been mapped to distal chromosome 4 (Lush et at., 1995: Bachmanov et at., 1997; Blizard et at., 1999). To assess TRl as a candidate gene for Sac, we compared the TR 1 cDNA sequences expressed in the tongue of C57BL/6ByJ (B6) and 129/J (129) mouse strains with different alleles of Sac. Using TRl sequence variation between the B6 and 129 strains, we conducted a high-resolution analysis of the chromosomal localization of the TRl and Sac loci in the F2 hybrids and Sac-congenic mice originating from these two strains. The TR 1 gene maps proximal to Sac, which demonstrates that they are different genes. Supported by NIH grants R01DC00882, RO1AAl 1028, ROl-DK44073 and R01DK48095.