Study on Expression,Purification of GFP-SA Recombine Protein and Anchoring Carcinoma Cells
GFP-SA融合蛋白的表达纯化及其锚定修饰肿瘤细胞的研究

Objective GFP (green fluorescence protein)-streptavidin (SA) bi-functional fusion protein was generated and characterized in order to demonstrate our novel platform for efficiently and durably modifying the cell surface with SA-tagged bi-functional proteins. Methods GFP-SA/pET24 construct was generated and expressed in BL21(DE3) host bacteria at the high level. The recombinant protein GFP-SA was purified through the Ni-NTA affinity chromatography, and then refolded. After biotinylation B16 tumor cells were modified with GFP-SA bi-functional fusion protein and then subjected to fluorescent microscopy and FACS analysis. The effect of surface modification on the viability and growth of B16.F10 tumor cells was evaluated by MTT staining. Results The GFP-SA recombinant fusion protein was expressed in BL21(DE3) at about 20 % of total bacterial proteins. The GFP-SA bi-functional fusion protein exhibited the bi-functionality, i.e., SA-mediated high-affinity binding to biotinylated cell surfaces and GFP-emitted green fluorescence. The cell surface modification with GFP-SA bi-functional fusion protein did not affect the viability and growth of the modified B16.F10 tumor cells significantly. Conclusion The GFP-SA bi-functional fusion protein was obtained and could be displayed efficiently on the surface of the biotinylated B16.F10 tumor cells through the specific and tight interaction between streptavidin and biotin, thus can be used as good trace protein and experimental control in the development of surface-modified tumor vaccine.