Molecular cloning and expression of human Gal beta 1,3GalNAc alpha 2,3-sialyltransferase (hST3Gal II)

A cDNA of human Gal beta 1,3GalNAc alpha 7,3-sialytransferase (hST3Gal II), which has been known to exhibit much more acceptor substrate preference for glycolipid than for O-linked oligosaccharides of glycoproteins, was isolated from the human liver cDNA library by plaque hybridization using the cDNA of mouse ST3Gal II (mST3Gal II) cloned previously as a probe. Comparative analysis of this cDNA with mST3Gal II indicates 89 and 94% homologies in the nucleotide and amino acid levels. respectively, between the two sequences in the predicted ending region. Northern analysis indicated that the expression of hSTSGal II mRNA is tissue-specific, it bring prominent in skeletal muscle and heart, while that in lung and kidney is very low. This enzyme expressed in COS cells showed a similiar activity with that of mSTSGal II. (C) 1996 Academic Press, Inc.