Objective To clone invasin gene from Yersinia pseudotuberculosi and express it in prokaryotic system.Methods According to the nucleic acid sequence of Yersinia pseudotuberculosi invasin gene deposited in GenBank

a pair of primers were designed and synthesized.The invasin gene was amplified by PCR and inserted into the pMD18-T vector

after confirmed with sequencing

the gene was subcloned into the prokaryotic expression vector pGEX-4T-1 and the recombinant plasmid pGEX-4T-inv was constructed.For expression of recombinant invasin protein

the recombinant plasmid was transformed into competent cell of E.coli BL21(DE3) after IPTG induction.The expressed fusion protein was confirmed by SDS-PAGE electrophoresis.Results An expected fragment 591 bp of invasin gene was amplified from the genomic DNA extracted from Yersinia pseudotuberculosis by PCR.The recombinant invasin gene was expressed after the induction with isopropyl-β-d-thiogalactoside(IPTG).The expressed GST-fused invasin core protein was stained on SDS-PAGE gel which showed the expected molecular weight of 46 kDa compared with the standard protein marker.After ultrasonic degradation

the recombinant was analyzed by 12% SDS-PAGE electrophoresis and the result showed that the recombinant protein was inclusion body.Conclusions Core fragment of the clonal invasin gene can highly express in prokaryocyte.