Three functional isoforms of GAR-2, a Caenorhabditis elegans G-protein-linked acetylcholine receptor, are produced by alternative splicing.
We have previously isolated a cDNA clone from Caenorhabditis elegans that encodes a novel form of G-protein-linked acetylcholine receptor, termed GAR-2. GAR-2 is similar to but pharmacologically distinct from muscarinic acetylcholine receptors. Here we report the identification of two gar-2 cDNA clones that are different from the previous one. These newly identified cDNAs encode polypeptides of 664 and 627 amino acids, whereas the previous one encodes a polypeptide of 614 amino acids. The three GAR-2 isoforms, which differ only in the third intracellular loop, arise from alternative splicing. Electrophysiological analyses using the Xenopus oocyte system showed that all three GAR-2 isoforms couple to the activation of G-protein-gated inwardly rectifying K+ (GIRK1) channel with similar drug specificity. Our results indicate that alternative splicing plays an important role in promoting molecular diversity of G-protein-linked acetylcholine receptors in C. elegans.
Suh
S J
SJ
Neurobiology Laboratory, Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea.
Park
Y S
YS
Lee
Y S
YS
Cho
T J
TJ
Kaang
B K
BK
Cho
N J
NJ
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D002478:Cells, Cultured; D018679:Cholinergic Agonists / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004553:Electric Conductivity; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D011950:Receptors, Cholinergic / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D014981:Xenopus
D029742:Caenorhabditis elegans Proteins; D018679:Cholinergic Agonists; D018680:Cholinergic Antagonists; C415370:G protein-linked acetylcholine receptor 2; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger; D011950:Receptors, Cholinergic; D020962:Heterotrimeric GTP-Binding Proteins