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

Abstract

Nicotinic acetylcholine receptors (AChRs) from muscle bind α-bungarotoxin (αBgt) and are composed of four kinds of subunits, whereas AChRs from mammalian brains do not bind αBgt and are composed of two kinds of subunits. αBgt-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 αBgt. 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 αBgt, but is different from αBgt-binding proteins in brain. Here we show that TE671 expresses the α-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 α-subunit protein for studies of the autoimmune response to muscle AChRs in human myasthenia gravis.