Blair L A, Levitan E S, Marshall J, Dionne V E, Barnard E A
MRC Molecular Neurobiology Unit, University of Cambridge, United Kingdom.
Science. 1988 Oct 28;242(4878):577-9. doi: 10.1126/science.2845583.
The alpha and beta subunits of the gamma-aminobutyric acidA (GABAA) receptor were expressed individually in Xenopus oocytes by injection of RNA synthesized from their cloned DNAs. GABA-sensitive chloride channels were detected several days after injection with any one of three different alpha RNAs (alpha 1, alpha 2, and alpha 3) or with beta RNA. The channels induced by each of the alpha-subunit RNAs were indistinguishable, they had multiple conductance levels (10, 19, 28, and 42 picosiemens), and their activity was potentiated by pentobarbital and inhibited by picrotoxin. The beta channels usually expressed poorly but showed similar single channel conductance levels (10, 18, 27, and 40 picosiemens), potentiation by pentobarbital and inhibition by picrotoxin. The finding that both alpha and beta subunits, examined separately, form GABA-sensitive ion channels with permeation properties and regulatory sites characteristic of the native receptor suggests that the amino acid sequences that confer these properties are within the homologous domains shared by the subunits.
通过注射从其克隆DNA合成的RNA，在非洲爪蟾卵母细胞中分别表达γ-氨基丁酸A（GABAA）受体的α和β亚基。注射三种不同的αRNA（α1、α2和α3）中的任何一种或βRNA几天后，检测到对GABA敏感的氯离子通道。由每种α亚基RNA诱导的通道没有区别，它们具有多个电导水平（10、19、28和42皮西门子），并且它们的活性被戊巴比妥增强，被印防己毒素抑制。β通道通常表达不佳，但显示出相似的单通道电导水平（10、18、27和40皮西门子），被戊巴比妥增强并被印防己毒素抑制。单独检查时，α和β亚基都形成具有天然受体渗透特性和调节位点的对GABA敏感的离子通道，这一发现表明赋予这些特性的氨基酸序列在亚基共享的同源结构域内。
