[Construction and expression of the prokaryotic expression vector of MTB cfpl0-esat6 fusion gene]

To begin with, we constructed cfp10-esat6 fusion gene and its prokaryotic expression vector and had it express in E. coli. By GeneSOEing techniques, a fusion gene was constructed by splicing cfpl0 gene and esat6 gene, and then was cloned into pGEX-4T-1 plasmid. Secondly, we constructed the prokaryotic expression recombinant plasmid pGcfp10-esat6. After identification with restriction enzyme analysis, PCR and nucleotide sequencing analysis, The E. coli BL21 containing the recombinant plasmid was induced by IPTG (Isopropy-beta-D-thiogalatoside). The fusion protein CFP10-ESAT6 with GST-tag about 42 kDa was expressed and purified with GST-fusion protein purification kit,The expression of cfp10-esat6 fusion gene was subsequently detected by SDS-polyacrylamine gel electrophoresis and Western-blot analysis. The sequence of cfp10 and esat6 in recombinant plasmid was consistent with that of GenBank report. The fusion protein existed in cytoplasm in soluble form and represented about 40% total bacterial protein of E. coil. The fusion protein was purified and the purity reached 90%. Its antigenicity was confirmed by Western-blotting. The prokaryotic expression vector (pGcfp1o-esat6) was constructed successfully, and the fusion protein CFP10-ESAT6 was obtained. This study provided an experimental basis for potential application of the recombinant CFP10-ESAT6 in the diagnosis of tuberculosis.