Latent taste diversity revealed by a vertebrate-wide catalogue of T1R receptors
Latent taste diversity revealed by a vertebrate-wide catalogue of T1R receptors
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DOI：
10.1101/2023.04.08.532961
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发表时间：
2023-04
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影响因子：
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通讯作者：
Hidenori Nishihara;Yasuka Toda;Tae Kuramoto;Kota Kamohara;Azusa Goto;Kyoko Hoshino;Shinji Okada;Shigehiro Kuraku;M. Okabe;Yoshiro Ishimaru
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作者：
Hidenori Nishihara;Yasuka Toda;Tae Kuramoto;Kota Kamohara;Azusa Goto;Kyoko Hoshino;Shinji Okada;Shigehiro Kuraku;M. Okabe;Yoshiro Ishimaru
味觉是摄食行为的重要化学感觉。在哺乳动物中，鲜味和甜味受体由1型味觉受体（T1 R/TAS 1 R）家族的三个成员组成：T1 R1，T1 R2和T1 R3。由于它们的功能同源物存在于硬骨鱼类中，只有三个由基因复制产生的TAS 1 R基因被认为是从骨脊椎动物的共同祖先遗传而来的。在这里，我们报告了五个以前未表征的TAS 1 R成员在脊椎动物中，命名为TAS 1 R4，5，6，7，和TAS 1 Rcf，通过全基因组调查的不同类群。对于TAS 1 R2和TAS 1 R3，发现哺乳动物和硬骨鱼基因是旁系同源的。系统发育分析表明，由于多个基因重复，骨脊椎动物祖先有9个TAS 1 R，一些TAS 1 R在每个谱系中独立丢失;最终，哺乳动物和硬骨鱼类只保留了3个TAS 1 R，而其他谱系保留了更多的TAS 1 R。在非硬骨鱼的功能测定和表达分析表明，新的T1 R形成异二聚体的味觉受体细胞，并有助于识别广泛的配体，如必需氨基酸，包括支链氨基酸，这是以前不被认为是T1 R配体。这些结果突出了现代脊椎动物和脊椎动物祖先味觉的意外多样性。味觉受体家族的复杂进化可能使脊椎动物能够适应地球上的不同栖息地。
Taste is a vital chemical sense for feeding behavior. In mammals, the umami and sweet taste receptors are composed of three members of the taste receptor type 1 (T1R/TAS1R) family: T1R1, T1R2, and T1R3. Because their functional homologs exist in teleosts, only three TAS1R genes generated by gene duplication are believed to have been inherited from the common ancestor of bony vertebrates. Here, we report five previously uncharacterized TAS1R members in vertebrates, named TAS1R4, 5, 6, 7, and TAS1Rcf, through a genome-wide survey of diverse taxa. For TAS1R2 and TAS1R3, mammalian and teleost fish genes were found to be paralogous. Phylogenetic analysis suggests that the bony vertebrate ancestor had nine TAS1Rs due to multiple gene duplications, and some TAS1Rs were lost independently in each lineage; ultimately, mammals and teleosts have retained only three TAS1Rs, whereas other lineages have retained more TAS1Rs. Functional assays and expression analysis in non-teleost fishes suggest that the novel T1Rs form heterodimers in taste receptor cells and contribute to the recognition of a broad range of ligands such as essential amino acids, including branched-chain amino acids, which were not previously considered as T1R ligands. These results highlight an unexpected diversity of taste sensations in both modern and the ancestors of vertebrates. The complex evolution of the taste receptor family might have enabled vertebrates to adapt to diverse habitats on Earth.