Regional expression patterns of T1r family in the mouse tongue
Regional expression patterns of T1r family in the mouse tongue
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DOI：
10.1093/chemse/bjh094
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发表时间：
2005-01-01
期刊：
影响因子：
3.5
通讯作者：
Hino, A
中科院分区：
文献类型：
--
作者：
Kusakabe, Y;Kim, MR;Hino, A
T1R家族是属于C类G蛋白偶联受体的受体家族之一，由三种味觉特异性受体T1R1、T1R2和T1R3组成(Nelson et al.，2001)。已知T1R1和T1R2分别具有不同的区域表达模式(Hoon等人，1999)。T1R1在菌状乳头的味蕾中表达，但在环状乳头的味蕾中很少表达。相反，T1R2在菌状乳头中很少表达，但在环状乳头的所有味蕾中都有表达。T1R3在菌状和环状乳头中都有强表达(Kitagawa等人，2001；Nelson等人，2001)，并分别与T1R1和T1R2结合形成氨基酸(Umami)受体和甜味受体(Nelson等人，2001；Li等人，2002)。这些表达模式表明，环状乳头中的味觉细胞通过T1R2和T1R3(T1R2/T1R3)的异源二聚体(T1R2/T1R3)接受甜味物质，而真菌状乳头中的味觉细胞通过T1R1和T1R3(T1R1/T1R3)的异源二聚体接受鲜味物质。然而，对小鼠的生理学研究表明，舌头前部和后部的味觉感受器细胞对甜味和鲜味物质都敏感(尼诺米亚等人，1993)。这一矛盾可能提示有关T1R家族表达的信息不足。我们用双色原位杂交方法比较了T1R受体(T1Rs)在小鼠环状乳头和菌状乳头中的表达模式。此外，我们还研究了T1Rs和味觉细胞特异性G蛋白Gustducin的表达模式，以比较环状和菌状乳头中的味觉信号转导。
The T1r family is one of the receptor family belong to class C type of G protein coupled receptors, and comprised of three taste budspecific receptors, T1r1, T1r2 and T1r3 (Nelson et al., 2001). T1r1 and T1r2 are known to have distinctive patterns of regional expression, respectively (Hoon et al., 1999). T1r1 is expressed in taste buds in the fungiform papillae, but is rare in the taste buds of circumvallate papillae. In contrast, T1r2 is rarely expressed in fungiform papillae but is expressed in all taste buds of the circumvallate papillae. T1r3 is strongly expressed in both fungiform and circumvallate papillae (Kitagawa et al., 2001; Nelson et al., 2001) and forms an amino-acid (umami) receptor and a sweet receptor in combination with T1r1 and T1r2, respectively (Nelson et al., 2001; Li et al., 2002). These expression patterns suggest that taste cells in circumvallate papillae receive the sweet taste substances through the heterodimer of T1r2 and T1r3 (T1r2/T1r3), and those in fungiform papillae receive the umami substances through the heterodimer of T1r1 and T1r3 (T1r1/T1r3). However, physiological studies in mice showed that taste receptor cells in the anterior as well as in the posterior parts of the tongue were sensitive to both sweet and umami substances (Ninomiya et al., 1993). This contradiction may suggest an inadequacy of information about the expression of T1r family. We compared T1r receptors (T1rs) expression pattern between circumvallate and fungiform papillae in mice using double-colored in situ hybridization. Furthermore, we examined the expression patterns of T1rs and the taste cell specific G protein, gustducin, in order to compare taste signal transductions in circumvallate and fungiform papillae.