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Use of Interferon-γ Enzyme-linked Immunospot Assay to Characterize Novel T-cell Epitopes of Human Papillomavirus
Published on: March 8, 2012
[Prokaryotic expression and identification of human papillomavirus type 16 E5 protein]
Qiao-fa Shi1, Xiao-li Wei, Hong Li
1Department of Microbiology, West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China. sqf741@sina.com.cn
Objective:
To construct the prokaryotic and eukaryotic expression vectors pET32/E5 and pcDNA3.1/E5 for transformation into E. coli BL21 and NIH(3)T(3) cells respectively to observe the expression of human papillomavirus type 16 E5 protein (HPV16 E5).
Methods:
HPV16 E5 gene was amplified by PCR from clinical isolates of HPV 16 and inserted into the plasmid pET32a(+) followed by digestion with BamH I and Hind III. The recombinant plasmid pET32/E5 was transformed into E. coli JM109 and selected with ampicillin. The positive clones containing the recombinant plasmid pET32/E5 were verified by restriction endonucleases BamH I and Xho and sequence analysis. The expression of HPV16 E5-TRX fusion protein in E. coli BL21(ED3) was identified by SDS-PAGE and Western blotting. The digestion product of BamH I and Xho was purified and inserted into the eukaryotic expression vector pcDNA3.1(+) to construct pcDNA3.1/E5, which was identified by sequencing and transfected into NIH3T3 cells. The NIH(3)T(3) cells with stable expression of HPV16 E5 were selected by G418 and confirmed by RT-PCR.
Results:
The pET32/E5 and pcDNA3.1/E5 vectors were constructed successfully. E.coli BL21(DE3) transformed by the recombinant plasmid pET32/E5 expressed HPV16 E5-TRX fusion protein efficiently. In the presence of 1 mmol/L IPTG at 28 degrees C, HPV16 E5-TRX recombinant protein accounted for about 10% of the total bacterial proteins. NIH3T3 cells stably expressing HPV16 E5 were harvested by selection with 250 g/ml of G418. HPV16 E5 gene from pcDNA3.1/E5-transfected NIH(3)T(3) cells was amplified by RT-PCR, and sequence analysis demonstrated the acquisition of the full-length gene fragment.
Conclusions:
The prokaryotic and eukaryotic vectors for the HPV16 E5 gene have been successfully constructed. The acquisition of E .coli and NIH(3)T(3) cells with stable expression of HPV16 E5 protein may facilitate subsequent research of the biological properties and the transformation mechanism of HPV16 E5 protein on specific cells.

