title: Apical Golgi localization of N,N'-diacetyllactosediamine synthase, beta4GalNAc-T3, is responsible for LacdiNAc expression on gastric mucosa.
abstract: beta1,4-N-acetylgalactosaminyltransferase III (beta4GalNAc-T3), which was recently cloned and identified, exhibits GalNAc transferase activity toward a GlcNAcbeta residue with beta1,4-linkage, forming the N,N'-diacetyllactosediamine, GalNAcbeta1,4GlcNAc (LacdiNAc or LDN). Though LacdiNAc has not been found in the gastric mucosa, a large amount of transcript was detected in our previous study. To increase our knowledge of beta4GalNAc-T3 expression and its product LacdiNAc, we examined the exact localization of beta4GalNAc-T3 in human gastric mucosa using a newly developed antibody, monoclonal antibody (mAb) K1356. This antibody specifically detected the enzyme that transfected the beta4GalNAc-T3 gene into MKN45 cells, and the terminal betaGalNAc epitope yielded on the cell surface was recognized by a lectin, Wisteria floribunda agglutinin (WFA). beta4GalNAc-T3 was localized in the supra-nuclear region of surface mucous cells in gastric mucosa, and WFA positively stained the mucins secreted by the cells. In contrast, in the cells of the glandular compartment in the fundic glands and a few cells in the pyloric glands, beta4GalNAc-T3 was observed in the basolateral position of the nucleus, where no WFA reactivity was detected. The anti-Tn (GalNAcalpha-O-Ser/Thr) antibody staining did not overlap with the WFA staining. By measuring the binding activity of WFA using automated frontal affinity chromatography (FAC), we found WFA to bind most strongly LacdiNAc among the sugar chains examined. Neither beta4GalNAc-T3 nor WFA-positive staining was detected in intestinal metaplastic cells. These results suggest that the supra-nuclear expression of beta4GalNAc-T3 is essential for the formation of LacdiNAc on the surface mucous cells and that LacdiNAc and beta4GalNAc-T3 are novel differentiation markers of surface mucous cells in the gastric mucosa.
authors.affiliation: Glycostructure Analysis Team, Research Center for Glycoscience, National Institute of Advanced Industrial Science and Technology, Open Space Laboratory Central-2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Ikehara
authors.forename: Takashi
authors.initials: T
authors.lastname: Sato
authors.forename: Toru
authors.initials: T
authors.lastname: Niwa
authors.forename: Sachiko
authors.initials: S
authors.lastname: Nakamura
authors.forename: Masanori
authors.initials: M
authors.lastname: Gotoh
authors.forename: Sanae Kabata
authors.initials: SK
authors.lastname: Ikehara
authors.forename: Katsue
authors.initials: K
authors.lastname: Kiyohara
authors.forename: Chihiro
authors.initials: C
authors.lastname: Aoki
authors.forename: Toshie
authors.initials: T
authors.lastname: Iwai
authors.forename: Hayao
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Jun
authors.initials: J
authors.lastname: Hirabayashi
authors.forename: Masae
authors.initials: M
authors.lastname: Tatematsu
authors.forename: Hisashi
authors.initials: H
authors.lastname: Narimatsu
mesh_terms: D000943:Antigens, Differentiation / Q000096:biosynthesis*; D045744:Cell Line, Tumor; D004187:Disaccharides / Q000096:biosynthesis*; D005753:Gastric Mucosa / Q000201:enzymology*; D006056:Golgi Apparatus / Q000201:enzymology*; D006801:Humans; D007785:Lactose / Q000031:analogs & derivatives* / Q000096:biosynthesis; D017350:N-Acetylgalactosaminyltransferases / Q000378:metabolism*
chemical_list: D000943:Antigens, Differentiation; D004187:Disaccharides; C093701:N-acetylgalactosaminyl-1-4-N-acetylglucosamine; C480161:B4GALNT3 protein, human; D017350:N-Acetylgalactosaminyltransferases; D007785:Lactose