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Assembly of an adult type acetylcholine receptor in a mouse cell line transfected with rat muscle ϵ‐subunit DNA
Author(s) -
Criado Manuel,
Koenen Michael,
Sakmann Bert
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81242-g
Subject(s) - protein subunit , acetylcholine receptor , microbiology and biotechnology , transfection , complementary dna , biology , interleukin 10 receptor, alpha subunit , cell culture , g alpha subunit , receptor , gene , biochemistry , genetics
The mouse muscle cell line BC3H‐1 expresses an acetylcholine receptor (AChR) composed of α‐,β‐, and δ‐subunits [1]. The functional characteristics of this AChR are comparable to the non‐synaptic AChR subtype in mouse muscle [2,3]. To investigate the role of the ϵ‐subunit, which is believed to replace the γ‐subunit in forming the adult AChR subtype [4], BC3H‐1 cells were stably transfected with cDNA encoding the rat muscle AChR ϵ‐subunit. Expression of this cDNA was under the control of a heat shock promoter, and the plasmid carried the neomycin resistance gene for selection. Several clones were isolated that had integrated the plasmid DNA in a stable form and produced ϵ‐subunit specific RNA after heat induction. Single‐channel current recording from cells which contained abundant ϵ‐subunit mRNA identified a novel AChR channel having a larger conductance than the native AChR in these cells. These results suggest that the rat muscle ϵ‐subunit may assemble with mouse muscle α‐, β‐ and δ‐subunits to form a mouse‐rat hybrid AChR with properties similar to that of end‐plate channels in the mature mammalian neuromuscular synapse. The novel AChR channel appears in the surface membrane within a few hours following the rise in ϵ‐subunit mRNA. Thus, the notion that replacement of the γ‐subunit by the ϵ‐subunit during development is the result of the postnatal rise in the level of ϵ‐subunit specific mRNA is further supported.