Divergent seven transmembrane receptors are candidate chemosensory receptors in C. elegans

Abstract

Using their senses of taste and smell, animals recognize a wide variety of chemicals. The nematode C. elegans has only fourteen types of chemosensory neurons, but it responds to dozens of chemicals, because each chemosensory neuron detects several stimuli. Here we describe over 40 highly divergent members of the G protein-coupled receptor family that could contribute to this functional diversity. Most of these candidate receptor genes are in clusters of two to nine similar genes. Eleven of fourteen tested genes appear to be expressed in small subsets of chemosensory neurons. A single type of chemosensory neuron can potentially express at least four different receptor genes. Some of these genes might encode receptors for water-soluble attractants, repellents, and pheromones.

Olfaction: Transient expression of a putative odorant receptor in the avian notochord

“…This gene is only expressed by AWA neurons, two of the 32 chemosensory neurons in C. elegans. More than 40 highly divergent members of this family of G-protein-coupled receptor in the C. elegans have been identified (39). Eleven of 14 tested receptor genes appear to be expressed in chemosensory neurons, but as observed in vertebrates, three of them are expressed in nonsensory cells.…”

Characterization of novel GPCR gene coding locus in amphioxus genome: Gene structure, expression, and phylogenetic analysis with implications for its involvement in chemoreception

“…Their gene structure contrasts sharply, however, with that of vertebrate ORs; their exons are interspersed among multiple introns (e.g., Robertson, 2000), and they show little sequence similarity with vertebrate olfactory receptors (Troemel et al, 1995;Sengupta et al, 1996;Clyne et al, 1999).…”

Dissecting a central flip-flop circuit that integrates contradictory sensory cues in C. elegans feeding regulation

“…1e), which is required for ASH-mediated avoidance of bitter tastes 8 . It has been reported that high concentrations of volatile repellents are also detected by ASH neurons 5 . OSM-9, the worm homologue of the vertebrate nociceptive channel TRPV1 (the capsaicin receptor), generally participates in perception of repellents by ASH neurons 12,13 .…”