cDNA cloning and expression of a bovine phenol UDP-glucuronosyltransferase, BovUGT1A6

A full-length cDNA encoding a phenol UDP-glucuronosyltransferase was isolat ed by plaque hybridization, RT-PCR acid 5'-RACE from a cDNA library prepare d from the bovine liver. The deduced amino acid sequence (529 amino acid re sidues) has A signal sequence (23 amino acid residues) at the amino terminu s and a transmembrane-anchoring domain (17 amino acid residues) at the carb oxyl ter minus. The encoded protein has a potential asparagine-linked glyco sylation site (Asn291). The cloned cDNA was named bovUGT1A6 on the basis of the amino acid similarity. BovUGT1A6 cloned in the pAAH5 expression vector was transformed into Saccharomyces cerevisiea AH22 cells to obtain an acti ve 54-kDa bovUGT1A6 enzyme. The expressed enzyme represented UDP-glucuronos yltransferase activities toward l-naphthol and 4-methylumbelliferone, comfi rming that the isolated cDNA is an isoform of bovine phenol UDP-glucuronosy ltransferase. Microsomal. UDP-glucuronosyltransferase activity toward l-nap hthol in the bovine kidney cortex was found to be higher than that in the l iver and other organs, and mRNA of bovUGT1A6 was more strongly detected in the kidney on Northern blotting analysis. These results suggest that the bo vine kidney, which strongly expresses bovUGT1A6, is a significant organ for xenobiotics glucuronidation. (C) 2001 Elsevier Science Inc. All rights res erved.