Identification of a dopamine receptor from Caenorhabditis elegans

The neurotransmitter dopamine regulates locomotion and egg laying in the nematode Caenorhabditis elegans. We have cloned a cDNA encoding the C. elegans G protein-coupled receptor (CeDOP1). The deduced amino acid sequence of the cloned cDNA shows high sequence similarities with D1-like dopamine receptors from other species. Three splice variants that differ in the length of the predicted third intracellular loop and C-terminal tail were identified. COS-7 cells transiently transfected with CeDOP1 showed high affinity binding to [1251] iodo-lysergic acid diethylamide (K-D = 3.43 +/- 0.83 nM). Dopamine showed the highest affinity (K-i = 0.186 muM) for this receptor among several vertebrate and invertebrate amine neurotransmitters tested, suggesting that the natural ligand for this receptor is dopamine. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.