What criteria should one use in choosing between siRNA versus shRNA for their studies?
This decision is based on two key factors the transfectability of the target cells, and the desired duration of the experiment. siRNA molecules work well for high throughput, transient studies, with cells that are easily transfected. The limitations of using siRNA are two-fold. First of all, they do not work well with cells that are difficult to transfect. In addition, their use is restricted to experiments studying the impact of transient suppression of gene expression. Because shRNA are carried within the context of a plasmid or viral-based vector, they can be engineered to carry a reporter gene. A reporter gene provides a straightforward readout, for carrying out transfection optimization studies. In addition, a fluorescent reporter gene (such as GFP) allows the use of fluorescence-activated cell sorting (FACS) to enrich for transfected cells. Alternatively, the vector may carry an antibiotic-resistance gene, which permits the selection of a stably transfected cell population. Anoth
