Transgenic silkworms that weave recombinant proteins into silk cocoons
- 1.1k Downloads
As a result of breeding for more than 4,000 years, the silkworm, Bombyx mori, has acquired the ability to synthesize bulk amounts of silk proteins in its silk glands. To utilize this capacity for mass production of useful proteins, transgenic silkworms were generated that synthesized recombinant proteins in the silk gland and secreted them into the silk cocoon. The silk gland is classified into two main regions: the posterior (PSG) and the middle silk gland (MSG). By controlling the expressed regions of the recombinant protein gene in the silk gland, we were able to control the localization of the synthesized protein in the silk thread. Expression in the PSG or MSG led to localization in the insoluble fibroin core or hydrophilic outer sericin layer, respectively. This review focuses on the expression of recombinant protein in the MSG of transgenic silkworms. The recombinant protein secreted in the sericin layer is extractable from the cocoon with only a small amount of endogenous silk protein contamination by soaking the cocoon in mild aqueous solutions. The possibility of utilizing transgenic silkworms as a valuable tool for the mass production of therapeutic and industrially relevant recombinant proteins is discussed.
KeywordsGlycosylation Recombinant protein Sericin Silk gland Transgenic silkworm
- Adachi T, Tomita M, Shimizu K et al (2006) Generation of hybrid transgenic silkworms that express Bombyx mori prolyl-hydroxylase alpha-subunits and human collagens in posterior silk glands: production of cocoons that contained collagens with hydroxylated proline residues. J Biotechnol 126:205–219PubMedCrossRefGoogle Scholar
- Shinkawa T, Nakamura K, Yamane N et al (2003) The absence of fucose but not the presence of galactose or bisecting N-acetylglucosamine of human IgG1 complex-type oligosaccharides shows the critical role of enhancing antibody-dependent cellular cytotoxicity. J Biol Chem 278:3466–3473PubMedCrossRefGoogle Scholar