Production of HPV16-L1 through BL21/pET32a expression system

Abstract

Introduction: The Human papillomaviruses (HPV) main capsid protein L1 is naturally capable to self-assemble as virus-like particles (VLPs). There are different recombinant protein expression systems such as bacteria, yeast, insect, plant, and mammalian cells for generation of VLP-based candidate vaccines targeting various pathogens. In this study, we produced HPV-L1 protein by BL21/pET32a expression system and VLP production was confirmed.Material & Method: The recombinant plasmid pET32/L1 was transformed into Escherichia. coli BL21 and selected with ampicillin. The positive clones containing the recombinant plasmid pET32/L1 were assessed by restriction endonucleases HindIII and XhoI and sequence analysis. The expression of HPV16-L1 fusion protein in E. coli BL21was identified by SDS-PAGE and Western blotting. VLPs were evaluated using electron microscopy.Result: A codon-optimized L1 gene was expressed in BL21 under the control of the T7/lac promoter. Purification of L1 protein was achieved after Ni NTA chromatography. The 60kDa protein was detected in the lysates of BL21, recognized as HPV16- L1 protein by Western blotting. VLPs were confirmed using electron microscopy.Conclusion: In this study, we established a high-efficient recombinant E. coli expression system for the production of HPV 16- L1 protein. The generated L1 protein was correctly self-assembled into VLPs. Therefore, BL21/pET32a as a prokaryotic expression system is a potent tool for HPV16-L1 VLP production.

Keywords

• hpv
• vlp
• vaccine
• bl21
• pet32