GENOME ORGANIZATION OF HUMAN 48-KDA OLIGOSACCHARYLTRANSFERASE (DDOST)

The enzyme oligosaccharyltransferase (dolichyl-diphosphooligosaccharid e-protein glycosyltransferase; EC 2.4.1.119) (DDOST) catalyzes the tra nsfer of a high-mannose oligosaccharide (GlcNac(2)Man(9)Glc(3)) from a dolichol-linked oligosaccharide donor (dolichol-P-GlcNac(2)Man(9)Glc( 3)) onto the asparagine acceptor site within an Asn-X-Ser/Thr consensu s motif in nascent polypeptide chains across the membrane of the endop lasmic reticulum. We isolated mouse and human DDOST cDNAs from retinoi c acid-treated mouse P19 EC cells and human NT-2 cells, respectively. DDOST mRNA is expressed intensely in heart and pancreas, but at lower levels in brain. Here we show that the human DDOST 48-kDa subunit gene (HGMW-approved symbol DDOST) is organized into 11 exons expanding abo ut 9 kb. This DDOST subunit gene is localized on chromosome 1p36.1 by fluorescence in situ hybridization analysis. (C) 1997 Academic Press.