Cloning and Expression of 60 kDa Outer Membrane protein Gene from Chlamydia Trachomatis

Objective To clone and express the 60kDa outer membrane protein gene (omp2) from Chlamydia trachomatis(Ct). Methods Ct serovar D was cultured through infected the McCoy monolayer cell and then the Ct template DNA was extracted from the cultured cells. PCR was used to amplify the omp2 gene fragment from Ct chromosomal DNA. The PCR products were directly ligated into pUCm-T vector. After being digested with BamHⅠ+ HindⅢ and purified, the omp2 gene fragment was inserted into the compatible site of prokaryotic expression vector pQE30, then the constructed recombinant plasmid was introduced into competent E. coli XL1-Blue. After restriction enzymes cleavage analysis and sequencing, the recombinant plasmid pQE30/omp2 was transferred into an expression stain E. coli M15. The host bacteria harboring the expression plasmid were induced by IPTG and the product was identified by SDS-PAGE. Result (1)The size of amplified omp2 gene was about 1650bp. The correct recombinant plasmid pQE30/omp2 was isolated and confirmed by restriction enzymes cleavage analysis. DNA sequencing showed the DNA sequence of the cloned gene was the same as the published sequence. (2)The fusion protein from the transformants was approximate size of 60 kDa in SDS-PAGE analysis. (3)Most of the expressed recombinant proteins were in inclusion bodies form. Conclusion We obtained omp2 gene of Ct and expressed it successfully in E.coli M15.