ABSTRACT
Objective:To construct His-tagged peptide of human STAT4 (565-748 amino acid) expression vector and induce its expression in Escherichia coli,followed by purification.Methods:STAT4 gene fragment encoding C-terminal peptide of 565-748 amino acid was amplified by PCR using pEGFP-STAT4 as the template.The PCR product was inserted into prokaryotic expression vector pET-28a and was transformed into component E.coli BL21 cells.By isopropyl-β-D-thiogalactoside(IPTG) induction,fusion protein was found to be expressed in the inclusion body and was denatured by using the urea denaturation buffer followed by renaturation and purifi-cation.Finally the purified protein was confirmed by Western blot.Results:The STAT4 truncated gene encoding 565-748 amino acids peptide was amplified by PCR and inserted into pET-28a vector.After the recombined plasmid was transformed into component BL21, the His-tagged-STAT4 (565-748 amino acids) fusion protein was induced and obtained after denaturation,refolding,purification and dialysis.Conclusion:The eukaryotic expression vector containing the truncated human STAT4 gene encoding 565-748aa peptide has been successfully constructed and the fusion protein was obtained.
ABSTRACT
To provide the basis for preparation of diagnostic kits and vaccines in Toxoplasma gondii infection, the gene coding for the qualified recombinant p30 protein (SAG1) of this parasite was amplified by PCR, and the amplified gene was cloned into prokaryotic expression vector pET-30a(+) to construct the recombinant plasmid, and then transformed to E.coli DH5α. The positive recombinant plasmid was screened by PCR and double enzymes digestion, and the nucleotide sequence of p30 gene was determined by automated DNA sequencing. Meanwhile, the identified recombinant plasmid was transformed to E.coli BL21(DE3) with the expression of p30 on bacteria induced by IPTG and the expressed protein was identified by SDS-PAGE. The protein obtained was then further purified and refolded, and its biological activity was checked by Western blotting. It was shown that the size of the amplified gene was 750 bp with molecular weight of 30 ku, and this protein could specifically react with monoclonal antibody against p30 protein.