Objective        To construct an eukaryotic expression vector encoding artificial transcription factor (ATF) which was designed to bind specifically HBV X gene promoter (HBV Xp) and compare its anti-virus effect on hepatitis B virus (HBV) in vitro with lamivudine (3TC).       Methods        Zinc finger tools 3.0 was used to select a sequence from the HBV Xp as the target site of zinc finger protein (ZFP)

and then the selected sequence was combined with an inhibitory effector structure domain kRAB. Then the nucleic acid sequence of total gene was synthesized and cloned into pcDNA3.1(+) to construct the recombinant plasmid pcDNA3.1(+)-nls-ZFP-kRAB-Flag(ATF)

pcDNA3.1(+)-nls-ZFP-Flag(ZFP1)

and pcDNA3.1(+)-nls-kRAB-Flag(ZFP2). Enzyme digestion and DNA sequencing was used to identify the correct of recombinant plasmid. Western blotting and immunofluorescence microscopy were used to determine the expression of recombinant plasmid in HepG2 cells. The recombinant plasmid or 3TC was transfected into HepG2.2.15 cells and cultured for 2

6 and 10 d respectively. Western blotting

fluorescent quantitative polymerase chain reaction (FQ-PCR) and ELISA were carried out to evaluate the expression of HBx

the copy numbers of HBV DNA and the contents of HBsAg and HBeAg

respectively.       Results        The recombinant plasmids were constructed correctly which could express well in the transformed HepG2 cells. ATF group reduced HBV X protein and HBV DNA significantly compared with other groups (P0.05)

and the inhibitory effect was stronger after 6 and 10 days' treatment than after 2 days'. 3TC group also reduced HBV X protein and HBV DNA significantly (P0.05). The secretion of HBsAg and HBeAg was significantly decreased in ATF group than other groups (P0.05). The secretion of HBsAg and HBeAg was also significantly decreased in 3TC group (P0.05).       Conclusion       The specific ATF is successfully expressed in eukaryotic cells and functions as an HBV inhibitor

even more effective than lamivudine.