Comparison of the N-linked glycosylation of human β1,3-N-acetylglucosaminyltransferase 2 expressed in insect cells and silkworm larvae

N-Glycosylation of human β1,3N-acetylglucosaminyltransferase 2 (β3GnT2) is essential for its biological function. β3GnT2 fused to GFPuv (GFPuv–β3GnT2) was produced by non-virus expression systems in stably transformed insect cells and silkworm larvae using a recombinant BmNPV bacmid, and purified for analysis of N-glycosylation. The N-glycan structure of β3GnT2 was identified by glycoamidase A digestion, labeling with 2-aminopyridine (PA), and HPLC mapping. The paucimannosidic N-glycan structure (73.2%) was predominant in stably transformed Trichoplusia ni cells. In contrast, N-glycan with Gal (21.3%) and GlcNAc (16.2%) terminal residues linked to Manα(1,3) branch were detected on β3GnT2 expressed in silkworm larvae. The presence of terminal Gal and bisecting GlcNAc residues such as Galβ1, 4GlcNAcβ1, 2Manα1,3(GlcNAcβ1,4)(Manα1,6)Manβ1, 4GlcNAc is not typical structure for lepidopteran insect N-glycosylation. Although allergenic α1,3-fucose residues have been found in T. ni cells, only α1,6-fucose residues were attached to the β3GnT2 glycan in silkworm larvae. Therefore, silkworm larvae might be a useful host for producing human glycoproteins.