Characterization of wheat germ agglutinin ligand on soluble glycoproteins in Caenorhabditis elegans.
Some mutants of Caenorhabditis elegans show altered patterns of ectopic binding with wheat germ agglutinin (WGA). Some of these mutants also have defects of morphogenesis and movement during development. To clarify the structures of WGA-ligands in C. elegans that may be involved in developmental events, we have analyzed glycan structures capable of binding WGA. We isolated glycoproteins from wild-type C. elegans by WGA-affinity chromatography, and analyzed their glycan structures by a combination of hydrazine degradation and fluorescent labeling. The glycoproteins had oligomannose-type and complex-type N-glycans that included agalacto-biantenna and agalacto-tetraantenna glycans. Although the complex-type glycans carried beta-GlcNAc residues at their non-reducing ends, they did not bind to the WGA-agarose-resin. Thus, it was suggested that these N-glycans were not responsible for WGA-binding of the isolated glycoproteins. Hydrazinolysis of the glycoproteins also released a considerable amount of GalNAc monosaccharide. It was surmised that N-acetylgalactosamine was derived from mucin-type O-glycans with the Tn-antigen structure (GalNAcalpha1-O-Ser/Thr). WGA-blotting assay of neoglycoproteins revealed that a cluster of Tn-antigens was a good ligand for WGA. These results suggested that the WGA-ligand in C. elegans is a cluster of alpha-GalNAc monosaccharides linked to mucin-like glycoprotein(s). The observations reported in this paper emphasize the possible significance of mucin-type O-glycans in the development of a multicellular organism.
Natsuka
Shunji
S
Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka.
Kawaguchi
Masahumi
M
Wada
Yukiko
Y
Ichikawa
Akira
A
Ikura
Koji
K
Hase
Sumihiro
S
D000818:Animals; D017173:Caenorhabditis elegans / Q000737:chemistry*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry*; D002240:Carbohydrate Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000737:chemistry*; D008024:Ligands; D008969:Molecular Sequence Data; D009077:Mucins; D011134:Polysaccharides / Q000032:analysis*; D012995:Solubility; D013329:Structure-Activity Relationship; D014909:Wheat Germ Agglutinins / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D006023:Glycoproteins; D008024:Ligands; D009077:Mucins; D011134:Polysaccharides; D014909:Wheat Germ Agglutinins