A Significant Increase of RNAi Efficiency in Human Cells by the CMV Enhancer with a tRNAlys Promoter

Abstract

RNA interference (RNAi) is the process of mRNA degradation induced by double-stranded RNA in a sequence-specific manner. Different types of promoters, such as U6, H1, tRNA, and CMV, have been used to control the inhibitory effect of RNAi expression vectors. In the present study, we constructed two shRNA expression vectors, respectively, controlled bytRNAlysand CMV enhancer-tRNAlyspromoters. Compared to the vectors withtRNAlysor U6 promoter, the vector with a CMV enhancer-tRNAlyspromoter silenced pokemon more efficiently on both the mRNA and the protein levels. Meanwhile, the silencing of pokemon inhibited the proliferation of MCF7 cells, but the induction of apoptosis of MCF7 cells was not observed. We conclude that the CMV enhancer-tRNAlyspromoter may be a powerful tool in driving intracellular expression of shRNA which can efficiently silence targeted gene.