Primary structure and functional expression of a developmentally regulated skeletal muscle chloride channel

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Item Type:	Article
Title:	Primary structure and functional expression of a developmentally regulated skeletal muscle chloride channel
Creators Name:	Steinmeyer, K., Ortland, C. and Jentsch, T.J.
Abstract:	Skeletal muscle is unusual in that 70-85% of resting membrane conductance is carried by chloride ions. This conductance is essential for membrane-potential stability, as its block by 9-anthracene-carboxylic acid and other drugs causes myotonia. Fish electric organs are developmentally derived from skeletal muscle, suggesting that mammalian muscle may express a homologue of the Torpedo mamorata electroplax chloride channel. We have now cloned the complementary DNA encoding a rat skeletal muscle chloride channel by homology screening to the Cl- channel from Torpedo. It encodes a 994-amino-acid protein which is about 54% identical to the Torpedo channel and is predominantly expressed in skeletal muscle. Messenger RNA amounts in that tissue increase steeply in the first 3-4 weeks after birth, in parallel with the increase in muscle Cl- conductance. Expression from cRNA in Xenopus oocytes leads to 9-anthracene-carboxylic acid-sensitive currents with time and voltage dependence typical for macroscopic muscle Cl- conductance. This and the functional destruction of this channel in mouse myotonia suggests that we have cloned the major skeletal muscle chloride channel.
Keywords:	Amino Acid Sequence, Base Sequence, Chloride Channels, Chlorides, Molecular Cloning, Gene Expression, Membrane Proteins, Molecular Sequence Data, Muscle Development, Muscles, Oocytes, Messenger RNA, Sequence Alignment, Animals, Rats, Xenopus Laevis
Source:	Nature
ISSN:	0028-0836
Publisher:	Nature Publishing Group
Volume:	354
Number:	6351
Page Range:	301-304
Date:	28 November 1991
Official Publication:	https://doi.org/10.1038/354301a0
PubMed:	View item in PubMed

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