Researchers performing siRNA screens often employ hundreds or even thousands of siRNAs per experiment
- Convenient panel of 7 negative control siRNAs
- Simplifies finding the best negative controls for a particular screen
- Functionally proven to have minimal effects on cell proliferation and viability
- Validated for use in human, mouse, and rat cells
- Also includes a positive control siRNA with a clear cytotoxic phenotype for assessing siRNA delivery efficiency
As with experiments using individual siRNAs, effective negative and positive control siRNAs are essential for determining transfection efficiency and to control for the general effects of siRNA delivery in these screens. Negative control siRNAs are also critical for setting the “hit” threshold that determines whether an siRNA is considered as having a positive, negative, or neutral effect in a particular assay. Because of their importance, and due in part to the fact that some negative control siRNAs may have unintended effects in a particular assay, most researchers carefully test their negative control siRNAs before choosing ones for inclusion in their screen.
Ambion now offers the Silencer® siRNA Screening Control Panel, a set of seven unique negative control siRNAs that enable RNAi researchers to identify the best negative control(s) for their cell system. These siRNAs lack similarity to nucleotide sequences in all known human, mouse, and rat genes. They have been tested in cell-based screens and proven to have no significant effect on cell proliferation, cell viability, and cell morphology, highlighting their usefulness as negative controls. An example of the effect of transfecting these controls on cell number is provided in Figure 1A.
Figure 1.Effects on Relative Cell Number after Transfections with Silencer® Screening Control siRNAs. UMR106 (A) and HeLa (B) cells were reverse transfected with 30 nM siRNA [Silencer Negative Control siRNAs (A) and Silencer Kif11 siRNA (B)] in triplicate using siPORT™ NeoFX™ Transfection Agent. Three days after transfection, the cells were harvested, and the relative number of cells in each sample was measured in a fluorescence plate reader using a fluorescein diacetate substrate.
As an added benefit, a positive control siRNA to human, mouse, and rat Kif11 (Eg5) is included. Knockdown of Kif11, which encodes a kinesin family motor protein, leads to mitotic arrest (Figure 1B). Effective delivery of Kif11 siRNA can thus be easily assessed visually; it can also be measured by several cell-based assays.
Each of the seven negative control siRNAs, as well as the Kif11 siRNA, in the Silencer siRNA Screening Control Panel is provided dried at 1 nmol. Each control siRNA is also available individually at 5 nmol and can be custom packaged to provide larger amounts.