Stage- and tissue-specific expression of a beta-1,4-galactosyltransferase in the embryonic epidermis.
Changes in oligosaccharide structures of glycoconjugates have been observed, and are postulated to have key roles in embryonic development and differentiation. N-Acetylglucosamine (GlcNAc) beta-1,4-galactosyltransferase (beta4GalT) AKI showed different expression patterns in time and space, and different enzymatic activity from the other known family members. The epidermis of mouse embryo included a high level of AKI activities, which transferred galactose (Gal) to endogenous glycoprotein (molecular weight 130 kDa) (GP130). The maximum activity was for 13.5-d postcoitum embryos. Specific antibody against AKI inhibited 81% of GlcNAc betaGalT activities, which indicates that AKI represents the major part of the embryonic epidermis enzymes. AKI shows 2.2 times higher galactosyltransferase activity toward Gal-acceptor glucose with alpha-lactalbumin (alpha-LA) than toward GlcNAc without alpha-LA. AKI is also expressed in mouse melanoma and leukemia cell lines and in human basal cell carcinoma specimens. The GP130 Gal acceptor once galactosylated by AKI may be directly involved in epidermal differentiation and oncogenesis.
Uehara
K
K
Biologie de la Différenciation Epithéliale, UMR CNRS LEDAC, Institut Albert Bonniot, Université Joseph Fourier, Facultde Medlecine, La Tronche, France. uehara@m3.kufm.kagoshima-u.ac.jp
Thelu
J
J
D000368:Aged; D000818:Animals; D002280:Basal Cell Carcinoma / Q000201:enzymology; D002460:Cell Line; D004817:Epidermis / Q000196:embryology / Q000201:enzymology*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D005865:Gestational Age; D006801:Humans; D015603:Keratinocytes; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009237:N-Acetyllactosamine Synthase / Q000235:genetics*; D009928:Organ Specificity; D012878:Skin Neoplasms / Q000201:enzymology
D009237:N-Acetyllactosamine Synthase