Regulation of porcine circovirus type 2-like particles expressed in baculovirus expression system

摘要

Background: Porcine circovirus type 2 (PCV2) virus-like particles (VLPs) are an effective vaccine against post-weaning multisystemic wasting syndrome. Burst sequence (BS) and the chicken 5'-HS4 β-globin (HS4) insulator were used to improve the production of PCV2 VLPs in insect cells. Results: BS was used to modify the polyhedron (polh) promoter, and the chicken HS4 insulator was inserted downstream of the target gene expression cassette. This enhanced effect was detected by EGFP, a generally used protein as reporter. The transcription-level analysis demonstrated that the double BS and the chicken HS4 insulator improved the transcription levels of the target genes. At the same time, the two regulatory elements also improved the PCV2 VLPs' expression. PCV2 VLPs' expression levels increased by 14 and 24 % at 72 h p.i. Further research observed an additive effect when the double BS and the chicken HS4 insulator simultaneously acted on the expression of PCV2 VLPs, with the PCV2 VLPs' expression level increasing by 35 % at 72 h p.i. Conclusions: BS and HS4 insulator can be used to improve the production of PCV2 VLPs in insect cells.