The human medulloblastoma cell line TE671 expresses a muscle‐like acetylcholine receptor Cloning of the α‐subunit cDNA

Nicotinic acetylcholine receptors (AChRs) from muscle bind alpha-bungarotoxin (alpha Bgt) and are composed of four kinds of subunits, whereas AChRs from mammalian brains do not bind alpha Bgt and are composed of two kinds of subunits. alpha Bgt-binding proteins whose function is unknown are also found in brain. All these proteins belong to the same gene family. The human medulloblastoma cell line TE671 expresses a functional AChR which binds alpha Bgt. Surprisingly, the AChR of this neuron-derived cell line has electrophysiological, immunological and biochemical properties different from neuronal AChRs and very similar to muscle AChRs. The TE671 AChR binds alpha Bgt, but is different from alpha Bgt-binding proteins in brain. Here we show that TE671 expresses the alpha-subunit mRNA coding for the muscle AChR, thereby proving that TE671 expresses a muscle-type AChR that is not expressed in adult brain. The isolated cDNA clones should prove useful for expression of large amounts of human muscle-type AChR alpha-subunit protein for studies of the autoimmune response to muscle AChRs in human myasthenia gravis.