title: Identification of free glycan chain liberated by de-N-glycosylation of the cortical alveolar glycopolyprotein (hyosophorin) during early embryogenesis of the Medaka fish, Oryzias latipes.
abstract: In Medaka embryos (at the stages of blastulation to organogenesis), we found the presence of free glycan of which structure is identical with the multiantennary N-linked sugar chain of L-hyosophorin molecules which were originally present in the cortical alveoli of the unfertilized eggs in their precursor high molecular form. The free glycan-enriched fraction was separated from L-hyosophorin by chromatography on DEAE-Sephadex A-25 and Sephadex G-50 after removal of the sialic acid residues with exo-sialidase. Composition analysis, 400-MHz 1H NMR spectroscopy, and pyridylamination-hydrazinolysis-nitrous acid deamination of the free glycan showed the presence of di-N-acetylchitobiosyl structure at the reducing end, suggesting that the free glycan chain was derived from L-hyosophorin by the action of a specific peptide:N-glycosidase (PNGase). When we combine the previous finding of the hyosophorin-derived unique pentaantennary free glycan chain in the flounder embryos [A. Seko et al. (1989) J. Biol. Chem. 264, 15922-15929], it is anticipated that PNGase-catalyzed de-N-glycosylation of L-hyosophorin would be required at a certain stage of embryogenesis for L-hyosophorin to play a yet undefined functional role during early development.
authors.affiliation: Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Seko
authors.forename: K
authors.initials: K
authors.lastname: Kitajima
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001755:Blastocyst / Q000502:physiology; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D002852:Chromatography, Ion Exchange; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D029941:Fish Proteins; D005775:Gastrula / Q000502:physiology; D006023:Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009028:Morula / Q000502:physiology; D009844:Oligosaccharides / Q000302:isolation & purification; D009865:Oocytes / Q000502:physiology; D009990:Oryzias / Q000196:embryology*; D011134:Polysaccharides / Q000378:metabolism
chemical_list: D002241:Carbohydrates; D029941:Fish Proteins; D006023:Glycoproteins; D009844:Oligosaccharides; D011134:Polysaccharides; C061150:hyosophorin protein, Fish