Title : Structural variations of
O-linked oligosaccharides present in
leukosialin isolated from erythroid, myeloid, and T-lymphoid cell lines
Abstract :
- Structures of O-linked oligosaccharides of leukosialin isolated from K562 erythroid, HL-60 promyelocytic, and HSB-2 T-lymphoid cell lines were examined
- Leukosialin was isolated by specific immunoprecipitation from cells which were metabolically labeled with [3H]glucosamine, and glycopeptides were isolated after Pronase digestion
- O-Linked oligosaccharides were released by alkaline borohydride treatment, and the structures of purified oligosaccharides were elucidated by specific exoglycosidase digestion, Smith degradation, and methylation anaylsis
- Oligosaccharides from K562 cells were found to be GalNAcOH, Gal beta 1----3GalNAcOH, NeuNAc alpha 2----6GalNAcOH, NeuNAc alpha 2----3Gal beta 1----3GalNAcOH, Gal beta 1----3(NeuNAc alpha 2----6)GalNAcOH, and NeuNAc alpha 2----3Gal beta 1----3(NeuNAc alpha 2----6)GalNAcOH.
- On the other hand, oligosaccharides from HL-60 and HSB-2 cells were found to be NeuNAc alpha 2----3 Gal beta 1----3GalNAcOH, NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6(Gal beta 1----3)GalNAcOH, Gal beta 1----4GlcNAc beta 1----6(NeuNAc alpha 2----3)Gal beta 1----3)GalNAcOH, and NeuNAc alpha 2----3Gal beta 1----4GlcNAc beta 1----6(NeuNAc alpha 2----3Gal beta 1----3)GalNAcOH
- These results clearly indicate that leukosialin can be differently glycosylated with O-linked chains , and each erythroid or myeloid (and T-lymphoid) cell line expresses a characteristic set of O-linked oligosaccharides which differ in core structures as well as in sialylation