A DELAYED RECTIFIER POTASSIUM CHANNEL CLONED FROM BOVINE ADRENAL-MEDULLA - FUNCTIONAL-ANALYSIS AFTER EXPRESSION IN XENOPUS OOCYTES AND IN ANEUROBLASTOMA CELL-LINE

Using a cDNA library from bovine adrenal medulla, and, subsequently, a bovine genomic library, we have isolated the gene coding for a non in activating potassium channel. This gene encodes a 597-amino acid prote in which we have called BAK5 as its sequence is very similar to member s of Kv1.5 potassium channel family. Neuroblastoma cells (Neuro-2a cel l line) were stably transfected with BAK5 DNA. Protein expression was under the control of a heat-shock promoter. Transfected cells showed a current highly selective for potassium, insensitive to tetraethylammo nium but reversibly blocked by 4-aminopyridine. Oocytes injected with BAK5 mRNA also expressed a potassium current with the same characteris tics.