Abstract: Capsid (Cap) protein was the main structural protein of porcine circovirus type 2 (PCV2),and used as a main basis for PCV2 serological diagnosis in the clinical.In this study,the complete gene encoding Cap protein of PCV2 TJ strain was amplified by PCR using the specific primers designed according to the strain sequence (GenBank accession No.:KC751546),and then the amplified products were cloned into pET-32a(+) vector to construct recombinant plasmid pET32a-Cap.The recombinant fusion protein with about 48 ku was expressed by IPTG induction.The result of Western blotting analysis showed that the fusion protein had the positive reaction with anti-6×His tag monoclonal antibody and porcine serum against PCV2.We had successfully cloned Cap gene,constructed the prokaryotic expression vector,and then expressed Cap fusion protein,it provided the support for the establishment of PCV2 detection and development of subunit vaccine,and also made a foundation for the study of the function of PCV2.

Key words: porcine circovirus type 2 (PCV2); Cap gene; clone; prokaryotic expression