Human carbonic anhydrase XIV (CA14): cDNA cloning, mRNA expression, and mapping to chromosome 1

A full-length cDNA clone of a human carbonic anhydrase XIV (HGMW-approved g ene symbol CA14) was obtained and sequenced. The cDNA sequence was 1757 bp long and was predicted to encode a 337-amino-acid polypeptide with a molecu lar mass of 37.6 kDa. The deduced amino acid sequence of CA XIV showed an o verall similarity of 29-46% to other active CA isozymes. The highest percen tage similarity was with a transmembrane CA isoform, CA XII. As observed fo r CA XII, CA XIV has hydrophobic segments at both termini of the deduced pr otein for a putative signal sequence and a transmembrane domain. CA XIV sho wed low activity and was sensitive to acetazolamide, but not to sulfonamide . Northern blot analysis demonstrated an similar to 1.7-kb transcript in th e adult human heart, brain, liver, and skeletal muscle. RNA dot-blot analys is for CA XIV mRNA expression showed a strong signal in all parts of the hu man brain and a weaker signal in the colon, small intestine, urinary bladde r, and kidney. RT-PCR analysis showed an intense signal in the liver and sp inal cord and a faint signal in the kidney. No CA XIV mRNA was seen in the salivary gland and pancreas. In contrast, CA XII mRNA was expressed in the kidney, salivary gland, and pancreas, but not in the liver or spinal cord. The GA XIV gene was localized to human chromosome 1q21, These findings indi cate genetically distinct but closely related isoforms of human transmembra ne CAs, CA XII and CA XIV, which have different patterns of tissue-specific expression; (C) 1999 Academic Press.