The cys-loop ligand-gated ion channel gene superfamily of the nematode, Caenorhabditis elegans

Abstract

The nematode, Caenorhabditis elegans, possesses the most extensive known superfamily of cys-loop ligand-gated ion channels (cys-loop LGICs) consisting of 102 subunit-encoding genes. Less than half of these genes have been functionally characterised which include cation-permeable channels gated by acetylcholine (ACh) and gamma-aminobutyric acid (GABA) as well as anion-selective channels gated by ACh, GABA, glutamate and serotonin. Following the guidelines set for genetic nomenclature for C. elegans, we have designated unnamed subunits as lgc genes (ligand-gated ion channels of the cys-loop superfamily). Phylogenetic analysis shows that several of these lgc subunits form distinct groups which may represent novel cys-loop LGIC subtypes.

Fig. 1

Tree showing the cys-loop LGIC gene superfamily of C. elegans. This figure focuses on cys-loop LGIC subunits other than nAChRs although representative subunits of the nAChR groups are shown. For the complete C. elegans nAChR gene family, see (Jones et al. 2007). Based on protein sequence homology, the subunits are divided into eight groups with three highly divergent subunits, LGC-32, LGC-33 and LGC-34, not belonging to any group