Taste buds have a cyclic nucleotide-activated channel, CNGgust
Taste buds have a cyclic nucleotide-activated channel, CNGgust
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DOI：
10.1074/jbc.272.36.22623
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发表时间：
1997-09-05
影响因子：
4.8
通讯作者：
Abe, K
中科院分区：
文献类型：
--
作者：
Misaka, T;Kusakabe, Y;Abe, K
环核苷酸门控（CNG）通道是参与视觉和嗅觉等生理过程的重要因素。因此，存在某种CNG通道也在味觉中起作用的可能性。在本研究中，我们进行了逆转录-聚合酶链反应和基因组DNA克隆，其特征在于CNG通道（CNGgust）作为一个环核苷酸激活的物种在大鼠舌上皮组织中表达的味觉接收发生。用5 ′-末端快速扩增法获得了几种不同5 ′-末端序列的CNGgustcDNA克隆。由于CNGgust基因是单拷贝的，因此这种CNGgust变体的形成应该是由选择性剪接引起的。编码的蛋白质与已知的脊椎动物CNG通道具有50-80%的氨基酸序列同源性，特别是与牛睾丸CNG通道和人锥体CNG通道具有82%的同源性，当在人胚肾细胞中表达时，CNG gust是有功能的，在其中加入cGMP或cAMP时，其打开。免疫组织化学分析表明，使用针对CNGgust肽产生的抗体的通道被定位在轮廓乳头中的每个味蕾的孔侧，没有观察到退化的味蕾的信号后，舌咽神经去神经支配。所有这些结果，以及环核苷酸在味觉信号通路中的作用，都有力地表明了CNGgust参与了味觉信号转导。
Cyclic nucleotide-gated (CNG) channels have been characterized as important factors involved in physiological processes including sensory reception for vision and olfaction. The possibility thus exists that a certain CNG channel functions in gustation as well. In the present study, we carried out reverse transcription-polymerase chain reaction and genomic DNA cloning and characterized a CNG channel (CNGgust) as a cyclic nucleotide-activated species expressed in rat tongue epithelial tissues where taste reception takes place. Several types of 5'-rapid amplification of cDNA ends clones of CNGgust cDNA were obtained with various 5'-terminal sequences. As the CNGgust gene was a single copy, the formation of such CNGgust variants should result from alternative splicing. The encoded protein was homologous to known vertebrate CNG channels with 50-80% similarities in amino acid sequence, and particularly homologous to bovine testis CNG channel and human cone CNG channel with 82% similarities, CNGgust was functional when expressed in human embryonic kidney cells, where it opened upon the addition of cGMP or cAMP. Immunohistochemical analysis using an antibody raised against a CNGgust peptide demonstrated the channel to be localized on the pore side of each taste bud in the circumvallate papillae, with no signal observed for degenerated taste buds after denervation of the glossopharyngeal nerve. All these results, together with the indication that cyclic nucleotides play a role gustatory signaling pathway(s), strongly suggest the involvement of CNGgust in taste signal transduction.