Cloning and expression of a G protein-linked acetylcholine receptor from Caenorhabditis elegans.
We have isolated a cDNA clone from the nematode Caenorhabditis elegans that encodes a protein of greatest sequence similarity to muscarinic acetylcholine receptors. This gene codes for a polypeptide of 682 amino acids containing seven putative transmembrane domains. The amino acid identities, excluding a highly variable middle portion of the third intracellular loop, to the human m1-m5 receptors are 28-34%. When this cloned receptor was coexpressed with a G protein-gated inwardly rectifying K+ channel (GIRK1) in Xenopus oocyte, acetylcholine was able to elicit the GIRK current. This acetylcholine-induced current was substantially inhibited by the muscarinic antagonist atropine in a reversible manner. However, another muscarinic agonist oxotremorine and antagonists scopolamine and pirenzepine had little or negligible effects on this receptor. Taken together, these results suggest that the cloned gene encodes a G protein-linked acetylcholine receptor that is most similar to but pharmacologically distinct from muscarinic acetylcholine receptors.
Lee
Y S
YS
Institute for Molecular Biology and Genetics, Department of Biology, Seoul National University, Korea.
Park
Y S
YS
Chang
D J
DJ
Hwang
J M
JM
Min
C K
CK
Kaang
B K
BK
Cho
N J
NJ
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001483:Base Sequence; D015139:Blotting, Southern; D017173:Caenorhabditis elegans / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004594:Electrophysiology; D016166:Free Radical Scavengers / Q000494:pharmacology; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D019204:GTP-Binding Proteins / Q000378:metabolism*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008969:Molecular Sequence Data; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009865:Oocytes / Q000502:physiology; D010095:Oxotremorine / Q000494:pharmacology; D010890:Pirenzepine / Q000494:pharmacology; D015221:Potassium Channels / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying; D011976:Receptors, Muscarinic / Q000235:genetics* / Q000378:metabolism*; D012601:Scopolamine / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D012701:Serotonin / Q000494:pharmacology; D013566:Sympathomimetics / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology; D014981:Xenopus
D018076:DNA, Complementary; D016166:Free Radical Scavengers; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D011976:Receptors, Muscarinic; D013566:Sympathomimetics; D014665:Vasodilator Agents; D012701:Serotonin; D010890:Pirenzepine; D010095:Oxotremorine; D001285:Atropine; D012601:Scopolamine; D019204:GTP-Binding Proteins; D007545:Isoproterenol; D000109:Acetylcholine