title: Expression of new KDN-gangliosides in rainbow trout testis during spermatogenesis and their structural identification.
abstract: The developmental expression of 2-keto-3-deoxy-D-glycero-D-galacto-nononic acid-containing glycosphingolipids (KDN-gangliosides) in rainbow trout testis during spermatogenesis was studied using a monoclonal antibody, mAb.kdn3G, which recognizes the KDN alpha 2-->3Gal beta 1-->epitope. A major KDN-ganglioside found in mature sperm, (KDN)GM3, KDN alpha 2-->3Gal beta 1-->4Glc beta 1-->Cer (where Cer is ceramide), was expressed in testis throughout all stages of its maturation. On the contrary, four new KDN-gangliosides which were reactive with mAb.kdn3G were not detected in mature sperm, although they were identified in immature testis and expressed during spermatogenesis. The structures of these KDN-gangliosides were established by chemical, enzymatic and immunochemical methods as: (i) (KDN)GD1a, KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer; (ii) (KDN, Neu5Ac)GD1a, KDN alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(Neu5Ac alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer and Neu5Ac alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4(KDN alpha 2-->3)Gal beta 1-->4Glc beta 1-->Cer; (iii) (KDN) GD1 alpha, KDN alpha 2-->3Gal beta 1-->3(KDN alpha 2-->6)GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->Cer; and (iv) (KDN,Neu5Ac)GD1 alpha, KDN alpha 2-->3Gal beta 1-->3(Neu5Ac alpha 2-->6)GalNAc beta 1-->4Gal beta 1-->4Glc beta 1-->Cer. (KDN)GD1a and (KDN,Neu5Ac)GD1a first appeared at an early stage of spermatogenesis, but (KDN)GD1 alpha and (KDN,Neu5Ac)GD1 alpha were not expressed until 2 months prior to spermiation. While (KDN)GM3 was previously shown to contain only 4-sphingenine (d18:1) acylated with a C16:0 fatty acid, the new KDN-gangliosides discovered in this study were composed of 4-hydroxysphinganine (t18:0) or 4-sphingenine (d18:1), and were acylated with a C24:1 or C16:0 fatty acid. A possible function of these KDN-gangliosides is suggested.
authors.affiliation: Department of Biophysics and Biochemistry, Graduate School of Science, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Song
authors.forename: K
authors.initials: K
authors.lastname: Kitajima
authors.forename: S
authors.initials: S
authors.lastname: Inoue
authors.forename: K H
authors.initials: KH
authors.lastname: Khoo
authors.forename: H R
authors.initials: HR
authors.lastname: Morris
authors.forename: A
authors.initials: A
authors.lastname: Dell
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
mesh_terms: D000215:Acylation; D000818:Animals; D000911:Antibodies, Monoclonal; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D000939:Epitopes / Q000737:chemistry; D005732:Gangliosides / Q000096:biosynthesis* / Q000737:chemistry*; D007202:Indicators and Reagents; D008297:Male; D008745:Methylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D017686:Oncorhynchus mykiss; D012621:Seasons; D013079:Sperm Maturation; D013091:Spermatogenesis; D013110:Sphingosine / Q000031:analogs & derivatives / Q000032:analysis; D013400:Sugar Acids / Q000032:analysis*; D013737:Testis / Q000378:metabolism* / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D005732:Gangliosides; D007202:Indicators and Reagents; D009844:Oligosaccharides; D013400:Sugar Acids; C050008:3-deoxyglycero-galacto-nonulosonic acid; C012491:phytosphingosine; D013110:Sphingosine