Abstract: Objective To construct the eukaryotic expression vector,to identify and to investigate its expression of HEV ORF3 fusion protein His label. Methods HEV RNA was isolated from the serum of a male patient with hepatitis E, and the HEV ORF3 cDNA was synthesized by reverse transcription and specific primers,then directionally ligated into pcDNA3.1（-） his in the eukaryotic expression vector,and the sequence of the enzyme digestion and sequencing was detected. The vector plasmid was transfected into HepG2 cells,which was used to detect the target protein 4 days later,and the target protein was detected by Western blot with anti-His. Results The HEV RNA type I were successfully isolated;after antibiotic screening and enzyme digestion,the pcDNA3.1（-）-HEF3-His eukaryotic expression vector was successfully constructed. The vector was transfected into HepG2 cells,and after 96 h incubation, an 15 kDa protein was demonstrated suggesting the fusion protein existed. Conclusion The eukaryotic expression vector of HEV ORF3 and His tag fusion are successfully constructed,and transfected into HepG2 cells,which might lay a foundation for further study of HEV ORF3 protein.

Key words: Hepatitis E virus, Eukaryotic expression, Fusion protein