cDNA cloning and expression of UDP-glucose dehydrogenase from bovine kidney

• We have isolated a cDNA encoding UDP-glucose dehydrogenase from a bovine kidney cDNA-library, the first mammalian cDNA clone published. [After submission of the manuscript, a study appeared describing the molecular cloning and characterization of  the human and mouse UDP-glucose dehydrogenase genes(Spicer et al., 1998).] The enzyme catalyzes the conversion of UDP-glucose to UDP-glucuronicacid, an essential precursor in glycosaminoglycan biosynthesis. The cDNA has an open reading frame of 1482 nucleotides coding for a 55 kDa protein. Expression of the enzyme in COS-7 cells showed a 3-fold increase inUDP-glucose dehydrogenase activity; also, the C-terminal 23 amino acidswas shown not to be necessary for enzyme activity. Northernblots from human and mouse tissues reveal high expression in liver and low in skeletal muscle. Human tissues have a majortranscript size of 3.2 kilobases and a minor of 2.6 whereas mousetissues have a single 2.6 kilobase transcript. We have also developed a sensitive and direct assay using UDP-[14C]Glc as a substrate for detection of small amounts of UDPGDH activity. 

Nyckelord

UDP-Glc dehydrogenase

UDP-GlcA

glycosaminoglycan

proteoglycan

biosynthesis

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