Truncated ClC-1 mRNA in myotonic dystrophy exerts a dominant-negative effect on the Cl current

Jim Berg, Hong Jiang, Charles A. Thornton, Stephen C. Cannon

Research output: Contribution to journalArticle

19 Scopus citations


Background: Muscle fiber degeneration and myotonic discharges are the hallmarks of myotonic dystrophy (DM). The molecular basis for the myotonia was recently tied to abnormal splicing of the chloride channel (ClC-1) pre-mRNA, often resulting in UAG premature termination, which leads to decreased channel protein and therefore a reduced resting chloride conductance. Methods: The authors assessed the functional properties of two commonly occurring DM mRNA splice variants by expression in oocytes. Results: Neither splice variant coded for a functional Cl- channel. Co-injection of alternative splice variants with wild-type ClC-1 cRNA reduced the current density and accelerated channel closure upon repolarization of the membrane. Conclusions: These data show that the aberrantly spliced chloride channel message exerts a dominant negative effect that may contribute to the development of myotonia.

Original languageEnglish (US)
Pages (from-to)2371-2375
Number of pages5
Issue number12
StatePublished - Dec 28 2004


ASJC Scopus subject areas

  • Clinical Neurology

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