Nucleotide sequence and structure of the mouse carbonic anhydrase III gene

At least 14 distinct isozymes of carbonic anhydrase have been identified in mammals. These enzymes catalyze the hydration of carbon dioxide and are es sential for regulation of cellular pH and carbon dioxide transport. Carboni c anhydrase III is highly expressed in certain tissues, including muscle an d fat where it constitutes up to 25% of the soluble protein. We cloned a cD NA encoding mouse carbonic anhydrase III. This cDNA contains 1653 bp, consi sting of 79 bp in the 5' UTR, a 780 bp open reading frame, and 794 bp of th e 3' UTR, including two potential polyadenylation signals. Fluorescent in s itu hybridization confirmed the existence of a single copy of the gene on c hromosome 3. We then isolated the genomic DNA for mouse carbonic anhydrase III and analyzed its structure. The gene consists of seven exons and six in trons which spun 10.5 kb. The 5' flanking region of the genomic DNA is nota ble for a pyrimidine rich region consisting of two dinucleotide repeats con taining 23 and 20 TC pairs separated by the same 15 bp spacer. Published by Elsevier Science B.V.