The diversity of O-linked glycans expressed during Drosophila melanogaster development reflects stage- and tissue-specific requirements for cell signaling.
Appropriate glycoprotein O-glycosylation is essential for normal development and tissue function in multicellular organisms. To comprehensively assess the developmental and functional impact of altered O-glycosylation, we have extensively analyzed the non-glycosaminoglycan, O-linked glycans expressed in Drosophila embryos. Through multidimensional mass spectrometric analysis of glycans released from glycoproteins by beta-elimination, we detected novel as well as previously reported O-glycans that exhibit developmentally modulated expression. The core 1 mucin-type disaccharide (Galbeta1-3GalNAc) is the predominant glycan in the total profile. HexNAcitol, hexitol, xylosylated hexitol, and branching extension of core 1 with HexNAc (to generate core 2 glycans) were also evident following release and reduction. After Galbeta1-3GalNAc, the next most prevalent glycans were a mixture of novel, isobaric, linear, and branched forms of a glucuronyl core 1 disaccharide. Other less prevalent structures were also extended with HexA, including an O-fucose glycan. Although the expected disaccharide product of the Fringe glycosyltransferase, (GlcNAcbeta1-3)fucitol, was not detectable in whole embryos, mass spectrometry fragmentation and exoglycosidase sensitivity defined a novel glucuronyl trisaccharide as GlcNAcbeta1-3(GlcAbeta1-4)fucitol. Consistent with the spatial distribution of the Fringe function, the GlcA-extended form of the Fringe product was enriched in the dorsal portion of the wing imaginal disc. Furthermore, loss of Fringe activity reduced the prevalence of the O-Fuc trisaccharide. Therefore, O-Fuc glycans necessary for the modulation of important signaling events in Drosophila are, as in vertebrates, substrates for extension beyond the addition of a single HexNAc.
Aoki
Kazuhiro
K
Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602-4712, USA.
Porterfield
Mindy
M
Lee
Samuel S
SS
Dong
Brian
B
Nguyen
Khoi
K
McGlamry
Katherine H
KH
Tiemeyer
Michael
M
D000818:Animals; D004331:Drosophila melanogaster; D018507:Gene Expression Regulation, Developmental; D005966:Glucuronidase / Q000737:chemistry; D006031:Glycosylation; D007477:Ions / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods; D008954:Models, Biological; D008956:Models, Chemical; D009005:Monosaccharides / Q000737:chemistry; D009154:Mutation; D009844:Oligosaccharides / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry; D015398:Signal Transduction; D013997:Time Factors
D007477:Ions; D009005:Monosaccharides; D009844:Oligosaccharides; D011134:Polysaccharides; D005966:Glucuronidase