title: Lectin histochemistry shows fucosylated glycoconjugates in the primordial germ cells of Xenopus embryos.
abstract: Previous works have shown that glycoconjugates with terminal fucose (Fuc) are located in the primordial germ cells (PGCs) of some mammals and might play a role in the migration and adhesion processes during development. The aim of this work was to identify the terminal Fuc moieties of Xenopus PGCs by means of three Fuc-binding lectins: from asparagus pea (LTA), gorse seed (UEA-I), and orange peel fungus (AAA). The histochemical procedures were also carried out after deglycosylation pretreatments: beta-elimination with NaOH to remove O-linked oligosaccharides; incubation with PNGase F to remove N-linked carbohydrate chains; and incubation with alpha(1,2)- and alpha(1,6)-fucosidase. The PGCs were always negative for LTA and UEA-I, two lectins that have the highest affinity for Fuc alpha(1,2)-linked. However, the PGCs were strongly labeled with AAA, which preferentially binds to Fuc with alpha(1,3) or alpha(1,4) linkages and to Fuc alpha(1,6)-linked to the proximal N-acetylglucosamine. There was fainter labeling with AAA when the sections were preincubated with alpha(1,6)-fucosidase, but the labeling remained strong when the sections were pretreated with alpha(1,2)fucosidase. When the beta-elimination procedure was carried out, the PGC labeling with AAA was slight. If the PNGase F incubation was performed, the PGCs remained moderately positive for AAA. These data suggest that the Xenopus PGCs have Fuc moieties in O- and N-linked oligosaccharides, including Fuc alpha(1,6) linked to the innermost GlcNAc, and that the Fuc was not in alpha(1,2)-linkage.
authors.affiliation: Department of Cell Biology and Histology, University of the Basque Country, Leioa (Vizcaya), Spain.
authors.forename: Edurne
authors.initials: E
authors.lastname: Alonso
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Sáez
authors.forename: Juan F
authors.initials: JF
authors.lastname: Madrid
authors.forename: Francisco
authors.initials: F
authors.lastname: Hernández
mesh_terms: D000818:Animals; D004396:Coloring Agents; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000378:metabolism*; D005643:Fucose / Q000378:metabolism*; D006001:Glycoconjugates / Q000378:metabolism*; D006651:Histocytochemistry; D037121:Plant Lectins; D014981:Xenopus
chemical_list: D004396:Coloring Agents; D006001:Glycoconjugates; D037121:Plant Lectins; D005643:Fucose