摘要
Receptors for bitter, sugar, and other tastes have been identified in the fruit fly Drosophila melanogaster, while a broadly tuned receptor for the taste of acid has been elusive. Previous work showed that such a receptor was unlikely to be encoded by a gene within one of the two major families of taste receptors in Drosophila, the “gustatory receptors” and “ionotropic receptors.” Here, to identify the acid taste receptor, we tested the contributions of genes encoding proteins distantly related to the mammalian Otopertrin1 (OTOP1) proton channel that functions as a sour receptor in mice. RNA interference (RNAi) knockdown or mutation by CRISPR/Cas9 of one of the genes, Otopetrin-Like A (OtopLA), but not of the others (OtopLB or OtopLC) severely impaired the behavioral rejection to a sweet solution laced with high levels of HCl or carboxylic acids and greatly reduced acid-induced action potentials measured from taste hairs. An isoform of OtopLA that we isolated from the proboscis was sufficient to restore behavioral sensitivity and acid-induced action potential firing in OtopLA mutant flies. At lower concentrations, HCl was attractive to the flies, and this attraction was abolished in the OtopLA mutant. Cell type–specific rescue experiments showed that OtopLA functions in distinct subsets of gustatory receptor neurons for repulsion and attraction to high and low levels of protons, respectively. This work highlights a functional conservation of a sensory receptor in flies and mammals and shows that the same receptor can function in both appetitive and repulsive behaviors.
摘要译文
在果蝇果蝇Melanogaster中鉴定了苦，糖和其他口味的受体，而酸味的宽泛调整受体是难以捉摸的。以前的作用表明，这种受体不太可能在果蝇，“味觉受体”和“离子受体中的两个主要家族中的两个主要家庭中的基因内的基因编码。这里，为了鉴定酸性味剂受体，我们测试了编码与哺乳动物Otopertrin1（OTOP1）质子通道的蛋白质的基因的贡献在小鼠中用作酸受体。 RNA干扰（RNAi）敲打或突变或通过其中一种基因的CRISPR / CAS9的敲打或突变，otopetrin样（otopla），但不是其他（Otplb或Otpolcc）严重损害了具有高水平的甜溶液的行为排斥反应HCl或羧酸和大大降低的酸性诱导的作用电位从味道中测量。从稳定性中分离的耳骨同种型足以恢复卵突突变蝇中的行为敏感性和酸诱导的动作射击。在较低浓度下，HCl对苍蝇有吸引力，并且该吸引力被废除在Otopla突变体中。细胞类型特异性救援实验表明，分别在味觉受体神经元的不同子集中分别用于排斥和吸引力，分别对高低水平的质子。该工作突出了恒生和哺乳动物中的感觉受体的功能守恒，并且表明相同的受体可以在满意和排斥行为中起作用。
Anindya Ganguly [1];Avinash Chandel [1];Heather Turner [2];Shan Wang [1];Emily R. Liman [2];Craig Montell [1]. Requirement for an Otopetrin-like protein for acid taste in Drosophila[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2021,118(51): e2110641118