Chemoreception is mediated in Caenorhabditis elegans by members of the seven-transmembrane G-protein-coupled receptor class (7TM GPCRs) of proteins which are of the serpentine type [1]. Srab is part of the Sra superfamily of chemoreceptors. Chemoperception is one of the central senses of soil nematodes like C. elegans which are otherwise 'blind' and 'deaf' [2]. The expression pattern of the srab genes is biologically intriguing. Of the six promoters successfully expressed in transgenic organisms, one was exclusively expressed in the tail phasmid neurons, two were exclusively expressed in a head amphid neuron, and two were expressed both in the head and tail neurons as well as a limited number of other cells [3].

1: Divergent seven transmembrane receptors are candidate chemosensory receptors in C. elegans. Troemel ER, Chou JH, Dwyer ND, Colbert HA, Bargmann CI; Cell 1995;83:207-218. PMID:7585938

2: The putative chemoreceptor families of C. elegans. Robertson HM, Thomas JH; WormBook. 2006; [Epub ahead of print] PMID:18050473

3: Identification of a nematode chemosensory gene family. Chen N, Pai S, Zhao Z, Mah A, Newbury R, Johnsen RC, Altun Z, Moerman DG, Baillie DL, Stein LD; Proc Natl Acad Sci U S A. 2005;102:146-151. PMID:15618405