Objective To construct a fluorescent expression cell model of botulinum toxin type B light chain(BoNT/B,BLC),and evaluate the effect of small molecule compounds with this model.Methods The BLC gene was inserted into the fluorescent expression vector pEGFP-N1 to construct a recombinant plasmid before being transfected into the neural cell line Neuro-2a cells for expression.The fluorescence expression level of BLC-EGFP protein in the cells was observed under a fluorescence microscope,and the enzyme digestion activity and stability of BLC-EGFP in the cells were detected by Western blotting.Furthermore,the model was used to evaluate the effect of SRC kinase inhibitor KX2-391 on the intracellular stability of BLC-EGFP protein.Results The recombinant expression plasmid pEGFP-N1-BLC was constructed.It was found that the expression level of BCL-EGFP protein in Neuro-2a cells gradually increased over time,and that the intracellular substrate vesicle-associated membrane protein-2(VAMP-2)was cleaved after plasmid transfection.CHX was added to terminate protein synthesis after the plasmid was transfected for 12 h,and the intracellular level of BLC-EGFP did not change significantly within 72 h.Twenty-four hours of treatment with KX2-391 could significantly promote the intracellular degradation of BLC-EGFP protein.Conclusions A cell model of fluorescent expression of botulinum toxin type B light chain has been established,which provides a technical reserve for the subsequent study onthe intracellular persistence mechanism and intracellular antidote screening of botulinum toxin type B light chain.

Cardiovascular System/pathology* ; Constriction, Pathologic/genetics* ; Point Mutation ; Neurofibromin 1/genetics* ; Animals ; Mice