title: Co-expression of two distinct polysialic acids, α2,8- and α2,9-linked polymers of N-acetylneuraminic acid, in distinct glycoproteins and glycolipids in sea urchin sperm.
abstract: Naturally occurring polysialic acid (polySia) structures have a large diversity, primarily arising from the diversity in the sialic acid components as well as in the intersialyl linkages. In 2004, we demonstrated the presence of a new type of polySia, 8-O-sulfated N-acetylneuraminic acid (Neu5Ac) capped α2,9-linked polyNeu5Ac, on the O-glycans of a major 40-80 kDa sialoglycoprotein, flagellasialin, in sea urchin sperm. In this study, we demonstrated that another type of polySia, the α2,8-linked polyNeu5Ac, exclusively occurs on O-glycans of a 190 kDa glycoprotein (190 kDa-gp), whereas the α2,9-linked polyNeu5Ac is exclusively present on flagellasialin. The 190 kDa-gp is localized in both flagellum and head of sperm. We also demonstrated that polysialogangliosides containing the α2,8-linked polyNeu5Ac are present in sperm head. Thus, this study shows two novel features of the occurrence of polySia in nature, the co-localization of polySia with different intersialyl linkages, the α2,8- and α2,9-linkages, in a single cell and the occurrence of α2,8-linked polyNeu5Ac in glycolipids. Anti-α2,8-linked polyNeu5Ac antibody had no effect on fertilization, which contrasted with the previous results that anti-α2,9-linked polyNeu5Ac antibody inhibited sperm motility and fertilization. Based on these properties, distinct functions of α2,8- and α2,9-polySia structures are implicated in fertilization.
authors: Graduate School of Bioagricultural Sciences, Bioscience and Biotechnology Center Nagoya University, Nagoya 464-8601, Japan.
authors: Shinji
authors: S
authors: Miyata
authors: Nao
authors: N
authors: Yamakawa
authors: Masaru
authors: M
authors: Toriyama
authors: Chihiro
authors: C
authors: Sato
authors: Ken
authors: K
authors: Kitajima
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D001704:Biopolymers / Q000737:chemistry* / Q000276:immunology; D005306:Fertilization / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D006017:Glycolipids / Q000737:chemistry* / Q000276:immunology; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology; D008297:Male; D019158:N-Acetylneuraminic Acid / Q000737:chemistry* / Q000276:immunology; D012617:Sea Urchins / Q000166:cytology*; D013094:Spermatozoa / Q000737:chemistry* / Q000187:drug effects / Q000276:immunology
chemical_list: D000906:Antibodies; D001704:Biopolymers; D006017:Glycolipids; D006023:Glycoproteins; D019158:N-Acetylneuraminic Acid