Volume 273, October 1997 Volume 42, October 1997 

Pages C1176-C1185: S. Lindenthal, S. Schmieder, J. Ehrenfeld, and N. K. Wills. "Cloning and functional expression of a ClC Cl channel from the renal cell line A6." In the above paper, we reported the cloning and expression of a Cl channel (xClC-5) from the renal cell line A6. Specifically, injection of xClC-5 cRNA in Xenopus oocytes induced the appearance of a Cl conductance not found in control oocytes. To increase the efficiency of expression, our laboratories recently subcloned the coding regions of xClC-5 into two modified versions of the Xenopus oocyte expression vector pSP64T (P. A. Kreig and D. A. Melton. Functional messenger RNAs are produced by SP6 in vitro transcription of cloned cDNAs. Nucleic Acids Res. 12: 7057-7070, 1984). In these constructs, the xClC-5 ORF was flanked by 5' and 3' noncoding regions of the Xenopus -globin sequence, and a Kozak consensus sequence was introduced before the initiator ATG.

Both laboratories independently confirmed that the current induced after injection of cRNA synthesized from these constructs differed significantly from our previous results. The properties of the previously observed current were similar to an endogenous current in Xenopus oocytes recently reported by Buyse et al. (J. Biol. Chem. 272: 3615-3621, 1997) that appeared after ClC-6 or pICln cRNA injection. We conclude that our previous results were due to the activation of an endogenous current induced by xClC-5 cRNA injection.