The influence of exogenous tRNAser(CGA) on the expression of human papillomavirus E7 gene

Objective: To investigate whether the expression of exogenous tRNAser(CGA) can alter the translation efficiency of the HPV 6bE7 gene in mammalian Cos-1 cell. Methods: The recombinant eukaryotic expressing plasmids encoding tRNAser (CGA) (pSV-tRNAser ) and wild-type (pcDNA3-WtE7) or codon modified (pcDNA3-HuE7) HPV 6b E7 DNA were extracted and identificated by gel analysis of digested products. Cos-1 cells were co-transfected with pSV tRNAser (CGA) and pcDNA3-WtE7 or pcDNA3-HuE7. The expression of the E7 protein were analyzed by immunoflurecence at 48h after transfection. Results: Cos-1 cells co-transfected with pSV-tRNAser and pcDNA3-WtE7 expressed higher levels of E7 protein than similar cells transfected with pcDNA3-WtE7 only, and the cells transfected only by wild-type E7 plasmids were occasionally positive. The expression of codon modified E7 gene were much higher than wild-type E7 gene in transfected Cos-1 cells, but no difference observed between tranfected and co-transfeced groups. The specific tRNAser(CGA) DNA fragment was obtained from the transfected cell by Southern blot analysis. Conclusion: The data indicate that supplement of exogenous tRNAser(CGA)can partly enhance the expression of HPV 6b wild-type E7 gene in mammalian Cos-1 cells.