Expression and purification of human papillomavirus type16 L1 protein in a prokaryotic expression system / 生物医学工程学杂志

This study was intended to establish a method of purification of HPV16 L1 protein expressed in a prokaryotic system and to obtain the purified protein. The prokaryotic expression vector pGEX-4T-1-HPV16 L1 was constructed and transformed into E. coli BL21 cell, and induced by 1 mM IPTG to express HPV16L1 protein. The inclusion bodies were isolated and solubilized with 8 M urea. After the urea was removed by gradual dialysis, the denatured L1 protein were renatured and then were purified by affinity chromatography. The results showed that HPV16L1 protein formed inclusion bodies in bacterial expression system, suggesting that this assay can be used to purify HPV16L1 protein and hence provide a basis for studying the applications of HPV16 L1 protein.

Regulatory effect of cytokines on promoter activity of human transforming growth factor-?_1 gene / 中国免疫学杂志

Objective:To study the effect of the cytokines, tumor necrosis factor-?(TNF-?), interferon-?(IFN-?), interferon-?(IFN-?), platelet-derived growth factor BB(PDGF-BB), basic fibroblast growth factor(bFGF),on promoter activity of human transforming growth factor-?1(TGF-?1) gene.Methods:A construct of phTGF2.14 containing sequence from -1 328 bp to +812 bp of human TGF-?1 gene,linking with chloramphenicol acetyltransferase(CAT) as reporter gene,was transiently transfected into rat hepatic stellate cell line nFSC. The cells were subsequently treated with TNF-?,IFN-?,IFN-?,PDGF-BB,bFGF, and the CAT activity was assessed 48 hours after stimulation with each cytokines.Results:TNF-? of 10 ng/ml can increased the CAT activity of phTGF2.14 to 3.24 fold compared to control. IFN-? and IFN-? at 1 000 U/ml decreased CAT activity to (42?12)% and (58?6)% of control respectively.PDGF-BB,bFGF of 10 ng/ml had no effect on promoter activity of human TGF-?1 gene;Combined application of IFN-?,IFN-? and TNF-?,the promoter TGF-?1 gene were 1.32 and 1.46 fold compared with control,respectively.Conclusion:These data indicate that TNF-? can increase the promoter activity of human TGF-?1 gene, but IFN-?,IFN? can downregulate the CAT activites of phTGF2.14, and IFN-?,IFN-? can interdict the upregulate effect of TNF-? on phTGF2.14. We did not find PDGF-BB,bFGF have any effect on TGF-?1 promoter. These provided an essential evidence for study the interaction mechanism of cytokines in fibrogenisis diseases.

Effect of TGF-?1 on TGF-?1 gene promoter activity in mouse hepatic satellite cells / 中国免疫学杂志

Objective:To investigate the effects of TGF-?1 on promoter activity of human transforming growth factor-beta1(TGF-?1) gene.Methods:The fragments with different length of the 5′-end sequence of the human TGF-?1 gene between -1 328 bp to +812 bp were obtained from a healthy male person genomic DNA, and the sequences were fused to chloramphenicol acetyltransferase reporter gene in the pCAT-enhancer plasmid to construct five chimeric recombinant plasmids. These recombinant plasmids were transiently transfected into rat hepatic setellate cell line(nFSC) by FuGENE6 transfection methods. The cells transfected with chimeric recombinant plasmids were cultured on media in the absence or presence of TGF-?1(2 5 ng/ml),CAT activities in transfected cells were tested and compared.Results:The different concentration of TGF-?1 can prevent the proliferation of nFSC, and these effects are dose-dependent; The presence TGF-?1 can stimulate the CAT activity of cells transfected with phTGF0 585?phTGF1 120?phTGF1 423?phTGF1 680?phTGF2 140 up to 2～5 times higher then cells cultured with absence of TGF-?1.Conclusion:The TGF-?1 can stimulate CAT activities in nFSC transfected with phTGF0 585?phTGF1 120?phTGF1 423?phTGF1 680?phTGF2 140. These results suggest that TGF-?1 have an autoregulation effect on TGF-?1 gene.