HGNC Approved Gene Symbol: KCNA7
Cytogenetic location: 19q13.33 Genomic coordinates (GRCh38): 19:49,067,397-49,072,699 (from NCBI)
Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Present in all eukaryotic cells, their diverse functions include maintaining membrane potential, regulating cell volume, and modulating electrical excitability in neurons. The delayed rectifier function of potassium channels allows nerve cells to efficiently repolarize following an action potential. In Drosophila, 4 sequence-related K+ channel genes--Shaker, Shaw, Shab, and Shal--have been identified. Each has been shown to have a human homolog (Chandy et al., 1990; McPherson et al., 1991).
Kalman et al. (1998) reported the isolation of the mouse voltage-gated Shaker-related potassium channel gene, Kv1.7 (Kcna7). The mouse Kv1.7 channel was voltage-dependent and exhibited cumulative inactivation. Northern blot analysis revealed transcripts of approximately 3 kb in mouse heart and skeletal muscle.
Bardien-Kruger et al. (2002) found that the human KCNA7 gene encodes a protein of 456 amino acid residues containing cytoplasmic N- and C-termini, a central core domain composed of 6 transmembrane segments, and the characteristic pore-loop. The deduced human and mouse protein sequences were highly conserved (greater than 95%). The expression of KCNA7 in human adult heart was confirmed by RT-PCR studies.
Unlike other known Kv1 family genes that have intronless coding regions, Kalman et al. (1998) found that the protein-coding region of mouse Kv1.7 was interrupted by a 1.9-kb intron.
Bardien-Kruger et al. (2002) deduced the coding region of KCNA7 by aligning the mouse cDNA sequence with a human BAC clone and mouse EST sequences. The human intron was 1153 bp long and smaller than that of mouse (1929 bp).
Using a probe from the mouse in the study of somatic cell hybrids, McPherson et al. (1991) found that a seventh member of the Shaker-related potassium voltage-gated channel is encoded by a gene on human chromosome 19. Kalman et al. (1998) mapped the KCNA7 gene to human chromosome 19q13.3 and mouse chromosome 7.
Bardien-Kruger, S., Wulff, H., Arieff, Z., Brink, P., Chandy, K. G., Corfield, V. Characterisation of the human voltage-gated potassium channel gene, KCNA7, a candidate gene for inherited cardiac disorders, and its exclusion as cause of progressive familial heart block I (PFHBI). Europ. J. Hum. Genet. 10: 36-43, 2002. [PubMed: 11896454] [Full Text: https://doi.org/10.1038/sj.ejhg.5200739]
Chandy, K. G., Williams, C. B., Spencer, R. H., Aguilar, B. A., Ghanshani, S., Tempel, B. L., Gutman, G. A. A family of three mouse potassium channel genes with intronless coding regions. Science 247: 973-975, 1990. [PubMed: 2305265] [Full Text: https://doi.org/10.1126/science.2305265]
Kalman, K., Nguyen, A., Tseng-Crank, J., Dukes, I. D., Chandy, G., Hustad, C. M., Copeland, N. G., Jenkins, N. A., Mohrenweiser, H., Brandriff, B., Cahalan, M., Gutman, G. A., Chandy, K. G. Genomic organization, chromosomal localization, tissue distribution, and biophysical characterization of a novel mammalian Shaker-related voltage-gated potassium channel, Kv1.7. J. Biol. Chem. 273: 5851-5857, 1998. [PubMed: 9488722] [Full Text: https://doi.org/10.1074/jbc.273.10.5851]
McPherson, J. D., Wasmuth, J. J., Chandy, K. G., Swanson, R., Dethlefs, B., Chandy, G., Wymore, R., Ghanshani, S. Chromosomal localization of 7 potassium channel genes. (Abstract) Cytogenet. Cell Genet. 58: 1979 only, 1991.