New mammalian chloride channel identified by expression cloning

Nature. 1992 Mar 19;356(6366):238-41. doi: 10.1038/356238a0.


Ion channels selectively permeable to chloride ions regulate cell functions as diverse as excitability and control of cell volume. Using expression cloning techniques, a complementary DNA from an epithelial cell line has been isolated, sequenced and its putative structure examined by site-directed mutagenesis. This cDNA, encoding a 235-amino-acid protein, gave rise to a chloride-selective outward current when expressed in Xenopus oocytes. The expressed, outwardly rectifying chloride current was calcium-insensitive and was blocked by nucleotides applied to the cell surface. Mutation of a putative nucleotide-binding site resulted in loss of nucleotide block but incurred dependence on extracellular calcium concentration. The unusual sequence of this putative channel protein suggests a new class of ion channels not related to other previously cloned chloride channels.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cell Line
  • Chloride Channels
  • Cloning, Molecular*
  • DNA / chemistry
  • DNA / genetics
  • DNA / isolation & purification
  • Dogs
  • Electric Conductivity
  • Gene Expression*
  • Kidney
  • Kinetics
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Membrane Proteins / physiology
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Oocytes / metabolism
  • Plasmids
  • Transfection
  • Xenopus laevis


  • Chloride Channels
  • Membrane Proteins
  • DNA