Abstract: In order to research the biological activity of cocoonase expressed through eukaryotic expression system, cocoonase gene (GenBank accession number: EF428980) was cloned into baculovirus transfer vector pFastBac^TM1 to obtain pFast-cocoonase, and this recombinant vector was then transformed into DH10Bac competent cells. Cocoonase gene was verified to have been successfully transferred to recombinant bacmid by PCR. BmN cells were transfect ed with the recombinant bacmid through lipofectin mediated method to obatin rec ombinant baculovirus. SDS-PAGE analysis showed that a specific band of about 27.6 kD existed on the lane of expression products of recombinant baculovirus, which was consistent with predicted size of the target protein. SEM micrographs were taken after treating silkworm silk with the expressed protein, and the results s howed that the expressed protein could hydrolyze sericine to some extent.

Key words: Bombyx mori, cocoonase, eukar yotic expression, baculovirus system, Bac-to-Bac system