Fused expression of hepatitis B virus preS1 gene in Escherichia coli

The gene encoding the N terminal 1-65 amino acids of preS1 was amplified by PCR and fused to the 3′ end of hTNF α gene to form a hTNF α preS1 fused gene which was directly inserted into the expression vector pSB 92 between EcoRⅠ and BamHⅠ sites and under the control of P 1 promoter. The fused hTNF α preS1(1-65) gene can be expressed in E.coli by temperature induction. The expression level was up to more than 35% and expressed fussion protein was shown by a major band with a expected molecular weight about 25kD on SDS PAGE, and also confirmed by Western blot analysis with anti hTNFα monoclonal antibody and anti preS1 monoclonal antibody. After renaturation, the fused protien displayed the hTNFα biological activity. The preS1(1-65) gene is found to be accurately fused to hTNFα by sequence analysis.