AcMNPV-mediated expression of BmK IT promotes the apoptosis of Sf9 cells and replication of AcMNPV / 生理学报

Chinese scorpion Buthus martensii Karsch (BmK) venom is a rich source of neurotoxins which bind to various ion channels with high affinity and specificity and thus widely used as compounds to modulate channel gating or channel currents. To promote the insecticidal effects of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), the gene encoding an excitatory insect toxin, BmK IT, was inserted into the genome of AcMNPV to construct a recombinant baculovirus, AcMNPV-BmK IT. Spodopter frugiperda 9 (Sf9) cells were infected with AcMNPV and AcMNPV-BmK IT respectively for 24 h. Results from the MTT assay, TUNEL assay, analysis of the expression level of apoptosis-related proteins (c-Myc, cleaved-Caspase3, Bcl-2 and Bax) of Sf9 cells, the transcription level of key genes (38K, C42, P78, F) of AcMNPV, and viral propagation assay demonstrated that AcMNPV-mediated expression of BmK IT promoted the apoptosis of Sf9 cells and replication of AcMNPV. The results laid a foundation for further structural and functional analysis of BmK IT.

Soluble expression, purification and characterization of Bm K IT in Escherichia coli by intein-mediated system / 生物工程学报

To produce recombinant Buthus martensii Karsch insect toxin (BmK IT), BmK IT cDNA which fused a hexahistidine sequence at the C-terminus by PCR was inserted into pTWIN1 expression vector fused in frame with an upstream Ssp DnaB intein gene. The expression plasmid was transformed into E. coli BL21 (DE3) strain and protein expression was induced by IPTG. The CBD-Intein-BmK IT(his6) fusion protein was purified from cell lysates using Ni-NTA resin affinity chromatography. The intein was removed from fusion protein by on-column intein-mediated cleavage. BmK IT(his6) was purified through Superdex 75 gel chromatography to more than 95% homogeneity. The purified protein has both correct secondary structure and insecticidal activity.