cDNA cloning, genomic structure and chromosomal mapping of the mouse glucuronyltransferase-S involved in the biosynthesis of the HNK-1 carbohydrate epitope.

The HNK-1 carbohydrate epitope is expressed on a series of cell adhesion molecules and some glycolipids in the nervous system. Two glucuronyltransferases (GlcAT-P and GlcAT-S) are involved in the biosynthesis of the HNK-1 carbohydrate epitope. In this study, we isolated cDNA and genomic clones encoding the mouse glucuronyltransferase-S involved in the biosynthesis of the HNK-1 carbohydrate epitope and determined the structural organization of the gene. The deduced amino acid sequence of mouse GlcAT-S consists of 324 amino acids and has a type II membrane topology. The predicted amino acid sequence of mouse GlcAT-S is 98.1% identical to that of rat GlcAT-S. Northern blot analysis revealed that the mouse GlcAT-S transcript is specifically expressed in the nervous system. Moreover, the mouse GlcAT-S gene is composed of four exons spanning over more than 25 kilobase pairs. Southern blot analysis and chromosomal mapping indicated that the mouse GlcAT-S gene is a single copy gene and it was mapped to the A4-B region of mouse chromosome 1.