Identification of β1,3-galactosyltransferases responsible for biosynthesis of insect complex-type N-glycans containing a T-antigen unit in the honeybee

• Published in: Glycoconjugate journal 2015-05, Vol.32 (3-4), p.141-151
• Main Authors: Ichimiya, Tomomi, Maeda, Megumi, Sakamura, Shou, Kanazawa, Masato, Nishihara, Shoko, Kimura, Yoshinobu
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antigens, Viral, Tumor - metabolism; Bees - enzymology; Bees - genetics; Biochemistry; Biomedical and Life Sciences; Carbohydrate Conformation; Carbohydrate Sequence; Cloning, Molecular; Drosophila Proteins - chemistry; Galactose - metabolism; Galactosyltransferases - genetics; Galactosyltransferases - metabolism; Insect Proteins - genetics; Insect Proteins - metabolism; Life Sciences; Molecular Sequence Data; Original Article; Pathology; Polysaccharides - biosynthesis; Polysaccharides - chemistry; Sequence Homology, Amino Acid
• ISSN: 0282-0080; 1573-4986
• DOI: 10.1007/s10719-015-9585-7

Honeybees ( Apis mellifera ) produce unique complex-type N -glycans bearing a Galβ1-3GalNAc (T-antigen) unit, and honeybee-specific N -glycans are linked to royal jelly glycoproteins. In this study, we identified two novel honeybee β1,3-galactosyltransferase ( β1,3-GalT ) genes responsible for biosynthesis of the T-antigen in insect N -glycans. The products of the two putative β1,3-GalT genes (β1,3-GalT1 and β1,3-GalT2 ), which were expressed in Sf21 insect cells, transferred galactose (Gal) residues to GalNAc2GlcNAc2Man3GlcNAc2-PA to form the Galβ1-3GalNAc unit, indicating that the identified genes were involved in biosynthesis of the β1-3 Gal-containing N -glycan. Therefore, using biochemistry and molecular biology techniques, we revealed a unique N -glycan biosynthesis mechanism in the cephalic region of honeybees, which has not previously been found in other animal or plant cells.