Molecular Biology of Nicotinic Acetylcholine Receptors from Chicken Muscle and Brain

摘要: While it has been completely established that the AChR** as isolated from electroplaques of electric fish is composed four different polypeptides, such its subunit structure α2βγδ (as reviewed in detail elsewhere this Volume), evidence for so far less complete related AChRs skeletal muscle various vertebrates (Dolly and Barnard, 1984). Of course, sequencing cDNAs encoding several these revealed strong amino acid homology between their subunits those Torpedo AChR (summarised by Kubo et al., 1985). However, what appears to be a full complement identified, via DNAs, only calf (Kubo 1985) even there difference revealed. Thus, an additional cDNA bovine was recently identified (Takai 1985), which encodes fifth polypeptide, designated e subunit. Electrophysiological measurements on Xenopus oocytes injected with combinations subunit-specific mRNAs, conjunction Northern blot analysis, have shown s replaces γ during development (Mishina 1986). These findings led conclusion fetal adult forms receptor are α2βδe respectively complements. Even case, although considerable present species (Conti-Tronconi 1982a), correspondence each putative products proof they form two oligomers just noted, not yet demonstrated.