ACR-3, a Caenorhabditis elegans nicotinic acetylcholine receptor subunit. Molecular cloning and functional expression.
The molecular cloning and functional co-expression of a novel nicotinic acetylcholine receptor (nAChR) non-alpha subunit gene, acr-3, is described. Previously we determined the sequence and demonstrated the functional co-expression of acr-2, a nAChR non-alpha subunit gene from Caenorhabditis elegans. Analysis of the acr-2 genomic DNA revealed the existence of another potential nAChR subunit gene, acr-3, in the same orientation, only 281 bp downstream of acr-2. A cDNA containing the entire acr-3 coding sequence was isolated by RT-PCR and sequenced. The predicted protein contains the conserved features typical of nAChR non-alpha subunits and most closely resembles other invertebrate nAChR non-alpha polypeptides. Unusually, the highly conserved glycine residue (equivalent to residue 240 in the Torpedo alpha subunit) upstream of transmembrane domain 2 (m2) is replaced by a serine residue in ACR-3. When acr-3 cDNA was injected alone into Xenopus oocytes no levamisole-gated channel activity was observed. However when co-expressed with a C. elegans alpha subunit (UNC-38), ACR-3 contributed to the formation of levamisole-gated channels. The response of this hetero-oligomer to levamisole (100 microM) was reduced by the nAChR antagonists mecamylamine (1 microM) and d-tubocurarine (10 microM).
Baylis
H A
HA
Babraham Institute Laboratory of Molecular Signalling, Department of Zoology, University of Cambridge, UK.
Matsuda
K
K
Squire
M D
MD
Fleming
J T
JT
Harvey
R J
RJ
Darlison
M G
MG
Barnard
E A
EA
Sattelle
D B
DB
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018509:DNA, Helminth; D015870:Gene Expression; D006031:Glycosylation; D015801:Helminth Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011978:Receptors, Nicotinic / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014982:Xenopus laevis
C113546:ACR-3 protein, C elegans; D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; D018509:DNA, Helminth; D015801:Helminth Proteins; D011978:Receptors, Nicotinic