Why use vectors for shRNA delivery?
In mammalian cells, RNAi can be induced by the direct introduction of molecules that specifically knock down the expression of a selected gene and result in a loss-of-function phenotype. These knockdown molecules can be chemically synthesized, prepared by in vitro methodologies, or produced in a cell from a DNA vector template. The first two of these methods can only be used for transient knockdown and can be difficult to introduce into hard-to-transfect, non-dividing or primary cell types. The use of vectors to deliver a short-hairpin RNA (shRNA) expressed from a pol III promoter has expanded RNAi experimental options to include stable and inducible expression as well as viral delivery.
