Expression and N-glycan analysis of human 90K glycoprotein in Drosophila S2 cells.

Human 90K (h90K; Mac-2-binding protein) glycoprotein is a potential pharmaceutical due to its inhibitory activity against cancer metastasis and expansion. Here, h90K glycoprotein was produced in insect Drosophila S2 cell system, and its N-glycan pattern was analyzed. A plasmid encoding h90K gene, fused with a hexahistidine tag under the control of Drosophila metallotionein promoter, was stably transfected into S2 cells.

In vivo post-translational modifications of recombinant mussel adhesive protein in insect cells.

Mussel adhesive proteins (MAPs) have been suggested as promising bioadhesives for diverse application fields, including medical uses. Previously, we successfully constructed and produced a new type of functional recombinant MAP, fp-151, in a prokaryotic Escherichia coli expression system. Even though the E.

Expression of β-1,4-galactosyltransferase and suppression of β-N-acetylglucosaminidase to aid synthesis of complex N-glycans in insect Drosophila S2 cells.

Previously, we have shown that simple paucimannosidic N-glycan structures in insect Drosophila S2 cells arise mainly because of β-N-acetylglucosaminidase (GlcNAcase) action. Thus, in an earlier report, we suppressed GlcNAcase activity and clearly demonstrated that more complex N-glycans with two terminal N-acetylglucosamine (GlcNAc) residues were then synthesized. In the present work, we investigated the synergistic effects of β-1,4-galactosyltransferase (GalT) expression and GlcNAcase suppression on N-glycan patterns.

Suppression of beta-N-acetylglucosaminidase in the N-glycosylation pathway for complex glycoprotein formation in Drosophila S2 cells.

Most insect cells have a simple N-glycosylation process and consequently paucimannosidic or simple core glycans predominate. Previously, we have shown that paucimannosidic N-glycan structures are dominant in Drosophila S2 cells. It has been proposed that beta-N-acetylglucosaminidase (GlcNAcase), a hexosaminidase in the Golgi membrane which removes a terminal N-acetylglucosamine (GlcNAc), might contribute to simple N-glycosylation in several insects and insect-derived cells except S2 cells.

Recombinant mussel adhesive protein as a gene delivery material.

Efficient target gene delivery into eukaryotic cells is important for biotechnological research and gene therapy. Gene delivery based on proteins, including histones, has recently emerged as a powerful non-viral DNA transfer technique. Here, we investigated the potential use of a recombinant mussel adhesive protein, hybrid fp-151, as a gene delivery material, in view of its similar basic amino acid composition to histone proteins, and cost-effective and high-level production in Escherichia coli.

Statistical determination of optimal baculovirus infection condition for recombinant protein production in Drosophila S2 cells.

Insect Drosophila melanogaster S2 cell was developed as plasmid-based and, therefore, a nonlytic expression system for functional foreign proteins. To achieve multiple protein expressions, it was suggested that baculovirus be used on S2 cell system because baculovirus can infect S2 cells but cannot replicate inside the cells. Therefore, establishment of baculovirus infection conditions is the first important step and this should be properly optimized for production yield.

Recombinant baculovirus-based multiple protein expression platform for Drosophila S2 cell culture.

A platform for selective and controllable expression of multiple foreign protein types was developed in insect cell culture. Based on the fact that baculovirus cannot replicate in nonpermissive Drosophila melanogaster Schneider line 2 (S2) cells, S2 cells that stably express human erythropoietin (hEPO) under the control of the S2-derived inducible metallothionein (MT) promoter were infected with three types of recombinant baculoviruses, each of which expressed a different fluorescent protein gene under the control of MT promoter. Addition of copper sulfate as an inducer to infected, stably transfected S2 cells resulted in simultaneous expression of hEPO and three fluorescent proteins.

Facile and rapid direct gold surface immobilization with controlled orientation for carbohydrates.

Effective surface immobilization is a prerequisite for numerous carbohydrate-related studies including carbohydrate-biomolecule interactions. In the present work, we report a simple and rapid modification technique for diverse carbohydrate types in which direct oriented immobilization onto a gold surface is accomplished by coupling the amine group of a thiol group-bearing aminophenyl disulfide as a new coupling reagent with an aldehyde group of the terminal reducing sugar in the carbohydrate. To demonstrate the generality of this proposed reductive amination method, we examined its use for three types of carbohydrates: glucose (monosaccharide), lactose (disaccharide), and GM1 pentasaccharide.