Identification of a cDNA encoding a thiazide-sensitive sodium-chloride cotransporter from the human and its mRNA expression in various tissues

We report here the identification of a cDNA encoding a human thiazide-sensitive sodium-chloride cotransporter (hTSC) using a PCR-based method. The homology of the hTSC with rat TSC (rTSC) and rat bumetanide-sensitive sodium-potassium-chloride cotransporter (rBSC) was 86% and 64%, respectively, at the nucleotide level, and 92% and 61%, respectively, at the amino acid level. Using fluorescence in situ hybridization (FISH), the hTSC gene has been mapped to chromosome 16q13. Northern blot analysis using polyA⁺RNA from various human tissues, revealed a major 4.5 kb transcript and a minor 6.5 kb specifically in the kidney, but low level of expression was also observed in small intestine, placenta, prostate, colon, and spleen.