Cloning of ClC-2 chloride channel from murine duodenum and its presence inCFTR knockout mice

We report the cloning of a murine ClC-2 chloride channel cDNA from duodenal epithelium by reverse transcriptase polymerase chain reaction (RT-PCR) usi ng degenerate primers and by rapid amplification of cDNA ends (RACE)-PCR. O ther than CFTR, this represents the first cloned chloride channel from inta ct intestine. The ClC-2 cDNA predicts encoding of a 908 amino acid polypept ide with a calculated M-r of 99 373. The amino acid sequence of the murine ClC-2 chloride channel is over 94% identical to the ClC-2 chloride channel proteins of other species. Of interest is the finding that the ClC-2 mRNA i s expressed about the same level in duodena from both CFTR knockout and wil d-type mice. This is in keeping with the suggestion that ClC-2 might be a t herapeutic target in cystic fibrosis. (C) 1999 Elsevier Science B.V. All ri ghts reserved.