[Detection of HPV 58 and cloning of its E7 gene in cervical cancer]

Abstract

Objective: To detect HPV 58, a common type of human papillomavirus (HPV), clone and express its E7 gene from biopsy specimens of cervical cancer.

Methods: HPV 58 from 58 biopsy tissues of cervical cancer was detected by GP5+/GP6+ PCR followed by template-directed dye-terminator incorporation assay with fluorescence polarization detection (TDI-FP). HPV 58 E7 gene was amplified from one HPV 58-positive sample, and then cloned into pGEM-T Easy vector. The recombinant plasmid, HPV58E7-pGEM-T was confirmed by sequencing. Subsequently, E7 gene was cloned into prokaryotic expression vector pRSET-A. The constructed pRSET-58E7 plasmids were transfected into BL21(DE3) cells, and induced to express 58 E7 protein by IPTG.

Results: Among the 58 biopsy tissues of cervical cancer, 10 were HPV 58-positive, accounting for 19.2% of 52 HPV-positive cases. HPV 58 E7 gene was amplified from one HPV 58-positive sample. The constructed plasmids were identified containing HPV58 E7 gene by restriction enzyme analysis and sequencing. SDS-PAGE analysis showed that HPV58 E7 His6 fusion protein of M(r) 16 x 10(3) was expressed by pRSET-58E7 after induction by IPTG. The fusion protein accounted for 30% of total bacterial proteins.

Conclusion: HPV 58 is not uncommon in Chinese women with cervical cancer in Shaanxi province. Constructed HPV58 E7 recombinant plasmids can be effectively expressed in E.coli, which may provide a tool in diagnosis and vaccine design for HPV of HPV58-associated tumors.