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

N-Glycosylation of human beta 1,3N-acetylglucosaminyltransferase 2 (beta 3GnT2) is essential for its biological function. beta 3GnT2 fused to GFP(uv) (GFP(uv)-beta 3GnT2) 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 beta 3GnT2 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 Man alpha(1,3) branch were detected on beta 3GnT2 expressed in silkworm larvae. The presence of terminal Gal and bisecting GlcNAc residues such as Gal beta 1, 4GlcNAc beta 1, 2Man alpha 1,3(GlcNAc beta 1,4)(Man alpha 1,6)Man beta 1, 4GlcNAc is not typical structure for lepidopteran insect N-glycosylation. Although allergenic alpha 1,3-fucose residues have been found in T ni cells, only alpha 1,6-fucose residues were attached to the beta 3GnT2 glycan in silkworm larvae. Therefore, silkworm larvae might be a useful host for producing human glycoproteins. (C) 2009 Elsevier B.V. All rights reserved.