Abe K, Kusakabe Y, Tanemura K, Emori Y, Arai S
Department of Agricultural Chemistry, Faculty of Agriculture, University of Tokyo, Japan.
J Biol Chem. 1993 Jun 5;268(16):12033-9.
We have reported on the partial structures of a multigene family encoding GTP-binding protein (G protein)-coupled, seven-transmembrane receptors expressed in the tongue (Abe, K., Kusakabe, Y., Tanemura, K., Emori, Y., and Arai, S. (1993) FEBS Lett. 316, 253-256). Here we describe a full-length cDNA clone encoding a tongue cell-type specific receptor. The encoded protein consists of 312 amino acid residues. In overall structure, the protein is similar to known G protein-coupled, seven-transmembrane receptors such as an olfactory receptor (56% identity) but is significantly different in part, particularly in NH2-terminal extracellular and COOH-terminal cytoplasmic domain structures. Northern analysis showed that the mRNA for this protein is expressed only in the epithelium of the tongue, not in other organs. In situ hybridization experiments clearly indicated that the mRNA is expressed exclusively on the tongue apical surface, not on the reverse side of the tongue nor in its muscle layer. Expression was also detected in the taste buds and surrounding cellular tissues of the fungiform and circumvallate papillae. It is suggested that this gustatory receptor structurally related to olfactory receptors may be a candidate for a taste receptor.
我们已经报道了一个多基因家族的部分结构，该家族编码在舌中表达的GTP结合蛋白（G蛋白）偶联的七跨膜受体（阿部，K.，楠部，Y.，根本，K.，江守，Y.，和新井，S.（1993年）《欧洲生物化学学会联合会快报》316，253 - 256）。在此，我们描述了一个编码舌细胞类型特异性受体的全长cDNA克隆。所编码的蛋白质由312个氨基酸残基组成。在整体结构上，该蛋白质与已知的G蛋白偶联的七跨膜受体如嗅觉受体相似（同一性为56%），但在部分区域有显著差异，特别是在NH2末端细胞外和COOH末端细胞质结构域。Northern分析表明，该蛋白质的mRNA仅在舌上皮中表达，在其他器官中不表达。原位杂交实验清楚地表明，mRNA仅在舌顶端表面表达，不在舌的反面或其肌肉层表达。在菌状乳头和轮廓乳头的味蕾及周围细胞组织中也检测到了表达。提示这种与嗅觉受体结构相关的味觉受体可能是一种味觉受体的候选者。
