匂い分子と受容体

Odorants and their receptors

嗅覚受容体の同定は，BuckとAxelによる哺乳類の匂い受容体のクローニングから始まり，第二の嗅覚受容器官である鋤鼻器の受容体，線虫の化学受容体，そしてごく最近になってショウジョウバエの嗅覚受容体候補遺伝子が報告された。

これらの受容体はみなGタンパク共役型の7回膜貫通型受容体で，遺伝子ファミリーをなしているという点では共通だが，驚くべきことにこれら受容体ファミリーの間ではアミノ酸配列上の相同性は見つけることができない。

Buck and Axel first cloned a large family of odorant receptor from rat olfactory epithelium. Since then, many chemosensory receptors have been identified, including families of vomeronasal receptors, C. elegans olfactory and gustatory receptors, and olfactory receptors in Drosophila.

These receptors have common features ; they encode G-protein coupled, seven transmembrane-domain receptors and consist gene families with tens to one thousand members. Amazingly, however, one cannot find any significant amino acid similarities among these families.

Methods that enable us to study odorant molecules-odorant receptors interaction have been established. These include molecular genetics in C. elegans, gene transfer using mammalian cells and mRNA analysis from single olfactory neurons.