RNA interference in mammals: behind the screen

The discovery of RNA interference (RNAi) and the development of technologies exploiting its biology have enabled scientists to rapidly examine the consequences of depleting a particular gene product in a cell or an animal. The availability of genome-wide RNAi libraries targeting the mouse and human genomes has made it possible to carry out large scale, phenotype-based screens, which have yielded seminal information on diverse cellular processes ranging from virology to cancer biology. Today, several strategies are available to perform RNAi screens, each with their own technical and monetary considerations. Special care and budgeting must be taken into account during the design of these screens in order to obtain reliable results. In this review, we discuss a number of critical aspects to consider when planning an effective RNAi screening strategy, including selecting the right biological system, designing an appropriate selection scheme, optimizing technical aspects of the screen, and validating and verifying the hits. Similar to an artistic production, what happens behind the screen has a direct impact on its success.