Nicotinic acetylcholine receptors in the nematode Caenorhabditis elegans
Nicotinic acetylcholine receptors in the nematode Caenorhabditis elegans
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DOI：
10.1006/jmbi.1996.0248
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发表时间：
1996-05-03
影响因子：
5.6
通讯作者：
Bertrand, D
中科院分区：
文献类型：
--
作者：
Ballivet, M;Alliod, C;Bertrand, D
从秀丽隐杆线虫（Caenorhabditis elegans）文库中分离到两个cdna (Ce21和Ce13)，这两个cdna编码了鸟类α - 5神经元烟碱乙酰胆碱受体（nAChR）的保守结构域。与EMBL/Swissprot数据库中所有nAChR亚基的比对表明，Ce21蛋白与脊椎动物α 7亚基最相似，而Ce13蛋白与果蝇的ARD亚基最接近。将相应的基因分离并杂交到YAC网格上：Ce21位于染色体V上靠近his-23基因的位置，Ce13位于染色体I上非常靠近unc-29的位置。Ce21基因的结构与其他脊椎动物和无脊椎动物的nAChR基因进行了比较，发现与脊椎动物α 7基因共享的保守剪接位点数量最多。在非洲爪蟾卵母细胞系统中表达后，Ce21亚基组装成一个功能同源的nAChR，其特性与鸡α - 7受体的特性进行了比较。驱虫剂尼古丁激动剂左旋咪唑不能激活Ce21和α 7受体，但能有效拮抗它们对乙酰胆碱的反应。两种受体在使用激动剂后迅速脱敏，对尼古丁比对乙酰胆碱更敏感，并被二氢- β -红血碱有效阻断。然而，与α 7受体不同，Ce21受体对甲基莱卡乌头碱和α班加罗毒素相对不敏感。α 7和Ce21在蛋白质序列、基因结构和生理特性上的相似性表明α 7类nAChR亚基具有非常古老的谱系。(C) 1996学术出版社有限公司
Two cDNAs (Ce21 and Ce13) were isolated from a Caenorhabditis elegans library screened with a probe encoding conserved domains of the avian alpha 5 neuronal nicotinic acetylcholine receptor (nAChR). Alignments to all nAChR subunits in the EMBL/Swissprot data base demonstrate that the Ce21 protein most resembles the vertebrate alpha 7 subunit, whereas Ce13 is closest to the ARD subunit of Drosophila. The corresponding genes were isolated and hybridized to YAC grids: Ce21 maps on chromosome V near the his-23 gene, and Ce13 on chromosome I very near or at unc-29. The structure of the Ce21 gene was compared with that of other vertebrate and invertebrate nAChR genes and found to share by far the largest number of conserved splice sites with the vertebrate alpha 7 gene. Upon expression in the Xenopus oocyte system, the Ce21 subunit assembled into a functional homomeric nAChR, whose properties were compared with those of the chicken alpha 7 receptor. The anthelmintic nicotinic agonist levamisole is unable to activate the Ce21 and alpha 7 receptors, but efficiently antagonises their responses to ACh. Both receptors desensitise quickly upon agonist application, are more sensitive to nicotine than to acetylcholine, and are efficiently blocked by dihydro-beta-erythroidine. Unlike the alpha 7 receptor, however, the Ce21 receptor is relatively insensitive to methyllycaconitine and to alpha-bungarotoxin. The similarities in protein sequence, gene structure and physiological properties between alpha 7 and Ce21 suggest a very ancient lineage for the alpha 7 class of nAChR subunits. (C) 1996 Academic Press Limited