Should I use siRNA or vectors for in vivo RNAi?
A. RNAi can be delivered using two different approaches-siRNA synthetic duplexes or siRNA expressed from plasmids or viral vectors (shRNA, miRNAi). siRNA are becoming the method of choice for the fast development of therapeutics. They are easy to use, easy to design, and easy to synthesize. siRNA can be rapidly identified and multiple genes can be targeted at the same time. With RNAi vectors, the expression will be steadier as a result of the possibility of stable integration of the plasmid into the genome, and they have the ability to target nondividing cells such as stem cells, lymphocytes and neurons. The drawbacks are the danger of oncogenic transformation from insertional mutagenesis, and unanticipated toxicity from long-term silencing of human genes and/or having high amounts of siRNA inside the cell (Grimm D. et al.: Nature 441: 537-541 (2006)). Click for more information siRNA synthetic duplexes or siRNA expressed from plasmids or viral vectors (shRNA and miRNAi).
