Initial isolation and analysis of the human Kv1.7 (KCNA7) gene, a member of the voltage-gated potassium channel gene family

A novel human potassium channel gene was identified and isolated. The maxim al open reading frame encodes a protein of 456 amino acids. The predicted p roduct exhibits 91% amino acid identity to the murine voltage-gated potassi um channel protein Kv1.7 (Kcna7), which plays an important role in the repo larization of cell membranes. Based on the high similarity, the human gene has been classified as the ortholog of the mouse Kcna7 and given the name K v1.7 (KCNA7). A structural prediction identified a pore region characterist ic of potassium channels and six membrane-spanning domains. Northern expres sion analysis revealed the gene is expressed preferentially in skeletal mus cle, heart and kidney. However, it is expressed at lower level in other tis sues, including liver. A single mRNA isoform was observed, with a size of a pproximately 4.5 kb. Using fluorescence in situ hybridization, the gene was mapped to chromosomal band 19q13.4 (269.13 cR(3000)) A genomic sequence wa s identified in the database from this region, and the KCNA7 gene structure determined. Computational analysis of the genomic sequence reveals the loc ation of a putative promoter and a likely muscle-specific regulatory region . Initial comparison to the published murine Kcna7 cDNA suggested a differe nt N-terminal sequence for the human protein, however, further analysis sug gests that the original mouse sequence contained an error or an unusual pol ymorphism. (C) 2001 Elsevier Science B.V. All rights reserved.