CLONING AND CHARACTERIZATION OF HUMAN AND MOUSE HOMOLOGS OF THE DROSOPHILA CALCIUM-ACTIVATED POTASSIUM CHANNEL GENE, SLOWPOKE

Potassium channels play important roles in a wide variety of physiolog ical processes. Although several genes encoding voltage-activated pota ssium channels have been analyzed at the molecular level, no calcium-a ctivated potassium channel gene has yet been characterized in humans. In an effort to provide the foundation for functional analysis of such polypeptides we report the cloning of mouse and human homologs of the Drosophila melanogaster calcium-activated potassium channel gene, slo wpoke. Both the human and mouse genes encode polypeptides that have mo re than 50% amino acid identities with their Drosophila counterpart. I n addition, like the Drosophila slowpoke gene, both the mouse and huma n genes generate multiple transcripts by alternative splicing. The hum an gene maps to chromosome 10 based on the results of polymerase chain reaction analysis of genomic DNA from human-hamster hybrid cell lines . Because calcium-activated potassium channels participate in wide var iety of cellular functions including neuromuscular communication, secr etion and cellular immunity, their continued analysis promises to have broad biological and medical significance.