The murine calcium-sensitive chloride channel (mCaCC) is widely expressed in secretory epithelia and in other select tissues

The tissue and cellular expression pattern of a recently cloned murine calcium-sensitive chloride channel (mCaCC) was determined. In situ hybridization was performed on formalin-fixed, paraffin-embedded murine tissues using digoxigenin-labeled, single-stranded RNA probes. The data were substantiated with northern blot and reverse transcriptase-polymerase chain reaction analyses. All three assays consistently indicated strong expression in tissues with secretory or ion regulatory functions, such as mammary gland, respiratory and intestinal epithelia, gall bladder, pancreas, kidney, uterus, and epididymis. Additional mCaCC expression was observed in germinal centers of lymphatic tissues, in spermatids, and in keratinocytes of the skin, esophagus, and cornea. The results are in accordance with previous electrophysiological reports on calcium-activated chloride conductances in various murine exocrine secretory epithelia and suggest a role of mCaCC in transepithelial ion transport. However, expression in other than secretory tissues indicates a more complex function.