ABSTRACT

This chapter focuses on domestic silkworm, Bombyx mori, which has been domesticated for silk production for more than five thousand years. It describes glycoprotein biosynthesis pathway in insects including silkworm and studies on production and glycoengineering of glycoproteins in silkworm. Glycoproteins expressed in insect cells and silkworm possesses mainly paucimannose or high mannose type N-glycans. For pharmaceutical applications, the difference in N-glycan structure between insects and mammals causes recombinant glycoproteins to be biologically ineffective. Yeasts such as Saccharomyces cerevisiae and Pichia pastoris are widely used for glycoprotein production due to ease of handling, rapid growth, availability of various expression vectors and glycosylation machinery. The structural difference of N-glycans between silkworm and human causes immunogenicity and biological inactivity when recombinant glycoproteins expressed in silkworm are used as pharmaceuticals. The silkworm possesses putative genes for glycosyltransferases involved in complex type N-glycan biosynthesis.