Identification of three novel members of the calcium-dependent chloride channel (CaCC) family predominantly expressed in the digestive tract and trachea.

Three novel human sequences showing striking homology to the recently described bovine Ca2+/calmodulin kinase II-dependent epithelial chloride channel bCaCC have been identified in an expressed sequence tags database. Full-length clones were isolated using a 5' RACE approach. The encoded predicted proteins display 65% overall homology to bCaCC. Tissue expression patterns of the corresponding genes, designated as hCaCC-1, -2 and -3, appear to be highly restricted, with the first two genes primarily expressed in the digestive tract. Another original feature as compared to the CaCC family members is the fact that hCaCC-2 also shows expression in the brain. Taken together these findings demonstrate the existence of several CaCC-like genes in humans, some of which display distinct tissue specificity patterns within the CaCC subfamily of chloride channels.