Adult thymus expresses an embryonic nicotinic acetylcholine receptor-like protein.
The subunit composition of acetylcholine receptor-like protein(s) (AChR-LP) expressed by normal thymus was investigated. In skeletal muscle, the AChR exists in two forms, an embryonic form which contains the gamma-subunit and an adult form where the gamma-subunit is substituted by a different, homologous subunit called epsilon. Antibodies against unique sequence segments of the embryonic gamma-subunit and of the adult epsilon-subunit of bovine muscle AChR, in addition to antibodies specific for the alpha-, beta-, and delta-subunits of bovine muscle AChR, were used to probe immunoblots of AChR-LP(s) from bovine thymus. Subunits of approximate Mr 41 kDa, 48-54 kDa, 57 kDa and 67-72 kDa were recognized by anti-alpha, anti-beta, anti-gamma and anti-delta antibodies respectively. Anti-epsilon antibodies did not recognize any protein band from bovine thymus. AChR-LP similar or identical to the embryonic muscle AChR is therefore expressed in normal thymus.
Department of Biochemistry, College of Biological Sciences, University of Minnesota, St. Paul 55108.
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Nelson
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Conti-Tronconi
D000595:Amino Acid Sequence; D000818:Animals; D002038:Bungarotoxins / Q000378:metabolism; D002417:Cattle; D002846:Chromatography, Affinity; D004622:Embryo, Mammalian / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009132:Muscles / Q000737:chemistry; D011978:Receptors, Nicotinic / Q000032:analysis* / Q000276:immunology; D013950:Thymus Gland / Q000737:chemistry*
D002038:Bungarotoxins; D011978:Receptors, Nicotinic