title: Polylactosamine synthesis and branch formation of N-glycans in beta1,4-galactosyltransferase-1-deficient mice.
abstract: Analysis of glycans from erythrocyte membrane glycoproteins from beta1,4-galactosyltransferase-1 (beta4GalT-1)-deficient mice revealed moderately decreased galactosylation but comparable polylactosamine content compared to control beta4GalT-1(+/-) mice. The increased expression of more branched N-glycans was observed in beta4GalT-1(-/-) mice, and its extent was more remarkable in elder beta4GalT-1(-/-) mice (28 weeks old) than in younger beta4GalT-1(-/-) mice (6-9 weeks old). In relation to this issue, the less galactosylation of biantennary glycans was observed in the elder group, suggesting that beta4GalTs actually compete with N-acetylglucosaminyltransferases IV and V in erythroid cells. In contrast, approximately 80% of core 2 O-glycans were not beta1,4-galactosylated regardless of age of the knockout mice. These results suggest that beta4GalT-1 expressed in erythroid cells may regulate a constant branch formation of N-glycans and plays a predominant role in beta1,4-galactosylation of core 2 O-glycan.
authors.affiliation: Division of Biochemistry, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
authors.forename: Norihiro
authors.initials: N
authors.lastname: Kotani
authors.forename: Masahide
authors.initials: M
authors.lastname: Asano
authors.forename: Noboru
authors.initials: N
authors.lastname: Inoue
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Iwakura
authors.forename: Seiichi
authors.initials: S
authors.lastname: Takasaki
mesh_terms: D000375:Aging / Q000502:physiology; D000606:Amino Sugars / Q000096:biosynthesis* / Q000737:chemistry*; D000818:Animals; D004910:Erythrocyte Membrane / Q000737:chemistry* / Q000378:metabolism*; D005700:Galactosyltransferases / Q000172:deficiency*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008970:Molecular Weight; D025942:Oligosaccharides, Branched-Chain / Q000096:biosynthesis / Q000737:chemistry; D011134:Polysaccharides / Q000096:biosynthesis* / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D013329:Structure-Activity Relationship
chemical_list: D000606:Amino Sugars; D008562:Membrane Glycoproteins; D025942:Oligosaccharides, Branched-Chain; D011134:Polysaccharides; C066929:polylactosamine; D005700:Galactosyltransferases; C119701:beta-1,4-galactosyltransferase I