Apical Golgi localization of N,N'-diacetyllactosediamine synthase, β4GalNAc-T3, is responsible for LacdiNAc expression on gastric mucosa

• Published in: Glycobiology (Oxford) 2006-09, Vol.16 (9), p.777-785
• Main Authors: Ikehara, Yuzuru, Sato, Takashi, Niwa, Toru, Nakamura, Sachiko, Gotoh, Masanori, Ikehara, Sanae Kabata, Kiyohara, Katsue, Aoki, Chihiro, Iwai, Toshie, Nakanishi, Hayao, Hirabayashi, Jun, Tatematsu, Masae, Narimatsu, Hisashi
• Format: Article
• Language: English
• Subjects: 4GlcNAc; bovine serum albumin; BSA; chondroitin sulfate N-acetylgalactosaminyltransferases; CSGalNAc-T; FAC; FCM; FITC; flow cytometry; fluorescentisothianate; follicular stimulation hormone; frontal affinity chromatography; FSH; GalNAcβ1; gastric mucosa; hCG; HEK; human chorionic gonadotropin; human embryonic kidney; immunoglobulin; LacdiNAc or LDN; leutropin; mAb; monoclonal antibody; N′-diacetyllactosediamine; PBS; phosphate-buffer saline; thyrotropin; TSH; WFA; Wisteria floribunda agglutinin; β4GalNAc-T3 expression
• ISSN: 0959-6658; 1460-2423
• DOI: 10.1093/glycob/cwl005

β1,4-N-acetylgalactosaminyltransferase III (β4GalNAc-T3), which was recently cloned and identified, exhibits GalNAc transferase activity toward a GlcNAcβ residue with β1,4-linkage, forming the N,N'-diacetyllactosediamine, GalNAcβ1,4GlcNAc (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 β4GalNAc-T3 expression and its product LacdiNAc, we examined the exact localization of β4GalNAc-T3 in human gastric mucosa using a newly developed antibody, monoclonal antibody (mAb) K1356. This antibody specifically detected the enzyme that transfected the β4GalNAc-T3 gene into MKN45 cells, and the terminal βGalNAc epitope yielded on the cell surface was recognized by a lectin, Wisteria floribunda agglutinin (WFA). β4GalNAc-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, β4GalNAc-T3 was observed in the basolateral position of the nucleus, where no WFA reactivity was detected. The anti-Tn (GalNAcα-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 β4GalNAc-T3 nor WFA-positive staining was detected in intestinal metaplastic cells. These results suggest that the supra-nuclear expression of β4GalNAc-T3 is essential for the formation of LacdiNAc on the surface mucous cells and that LacdiNAc and β4GalNAc-T3 are novel differentiation markers of surface mucous cells in the gastric mucosa.