Germline transformation of Bombyx mori to express mammalian N-glycosylation enzymes sialic acid synthase and CMP-sialic acid synthetase.

The N-glycosylation pathway in insects differs from the mammalian pathway,which limits insect-based expression system to produce mammalian glycoproteins with biomedical value. This study aims to produce transgenic Bombyx mori capable of processing glycoproteins as mammalian glycosylation pathways. Two key genes in mammalian N-glycosylation pathway,i.e.,mammalian sialic acid synthase and CMP-sialic acid synthetase genes,which were driven by B. mori actin3 promoter,were transformed into B. mori by piggyBac transgenic system. Enhanced green fluorescent protein(EGFP) which was driven by 3×P3 promoter was also introduced as a molecular selection marker. The expression of transformed genes was analyzed in G1 transgenic silkworms. The current study provides a solid evidence of simulating mammalian glycosylation pathways in the model insect B. mori.