Cloning and Expression of a G Protein‐Linked Acetylcholine Receptor from Caenorhabditis elegans

• Published in: Journal of neurochemistry 1999-01, Vol.72 (1), p.58-65
• Main Authors: Lee, Yong‐Seok, Park, Yang‐Seo, Chang, Deok‐Jin, Hwang, Jung Me, Min, Churl Ki, Kaang, Bong‐Kiun, Cho, Nam Jeong
• Format: Article
• Language: English
• Subjects: Acetylcholine - pharmacology; Animals; Atropine - pharmacology; Base Sequence; Biochemistry. Physiology. Immunology. Molecular biology; Biological and medical sciences; Blotting, Southern; Caenorhabditis elegans; Caenorhabditis elegans - genetics; Cloning, Molecular; DNA, Complementary; Electrophysiology; Free Radical Scavengers - pharmacology; Fundamental and applied biological sciences. Psychology; G Protein-Coupled Inwardly-Rectifying Potassium Channels; G proteinlinked acetylcholine receptor; G protein‐gated inwardly rectifying K+ channel; GTP-Binding Proteins - metabolism; Invertebrates; Ion Channel Gating - drug effects; Ion Channel Gating - physiology; Isoproterenol - pharmacology; Membrane Potentials - drug effects; Membrane Potentials - physiology; Molecular Sequence Data; Muscarinic acetylcholine receptor; Muscarinic Agonists - pharmacology; Muscarinic Antagonists - pharmacology; Nemathelminthia. Plathelmintha; Oocytes - physiology; Oxotremorine - pharmacology; Physiology. Development; Pirenzepine - pharmacology; Potassium Channels - physiology; Potassium Channels, Inwardly Rectifying; Receptors, Muscarinic - genetics; Receptors, Muscarinic - metabolism; Scopolamine - pharmacology; Sequence Homology, Amino Acid; Serotonin - pharmacology; Sympathomimetics - pharmacology; Vasodilator Agents - pharmacology; Xenopus; Xenopus oocyte
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1046/j.1471-4159.1999.0720058.x

: 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.