Abstract: Objective To investigate the silencing effect of two kinds of RNA interference (RNAi)technology on the expression of HPV11 E7 gene in vitro.Methods A pair of small interference RNA(siRNA)targeting HPV11 E7 gene,named siRNA-11E7,was chemically synthesized,and three short hairpin RNA(shRNA)expression plasmids,i.e.pRNAT-11E7 1^#,2^#,3^#,were constructed.Then a murine melanoma cell line,B16,which stably expressed HPV11 E7 gene,was transfected respectively with the siRNA-11E7 and pRNAT-11E7 1^#,2^#,3^#,etc.The level of E7 mRNA expression was detected in these cells by real-time fluorescent quantitative PCR before and after the transfection.Results siRNA-11E7 could inhibit the E7 gene mRNA expression in B16 cells by 12.60%,31.41%,41.93%,42.93%,74.35%,32.71% and 29.00% at 6 h,12 h,24 h,48 h,72 h,96 h and 120 h after the transfection,respectively.The optimal dose of siRNA was 25 nmol/L with an inhibition rate of 70.06%,and the lowest effective dose was 3.13 nmol/L with an inhibition rate of 47%.The 0.4μg of pRNAT-11E7 1^#,2^#,3^# and a mix of the 3 plasmids could decrease the target gene expression by 44.52%,59.26%,89.62%,54.09%,respectively,while the negative plasmid had no inhibitory effect on the gene expression,pRNAT-11E7 3^# could decrease the E7 gene expres-sion by 0,17.50%,40.90%,42.40%,61.90%,51.50% and 0,at 6 h,12 h,24 h,48 h,72 h,96 h and 120 h after the transfection,respectively.The optimal dose ofpRNAT-11E7 was 0.2μg.Conclusions Both siRNA and shRNA expression plasmids could efficiently and safely silence the HPV11E7 mRNA expression in a time-and dose-dependent manner,and the optimal action dose and time is likely to be identified.

Key words: Gene silencing, RNA interference, Papillomavirus,human