Off-target effects by siRNA can induce toxic phenotype.
Although recent microarray studies have provided evidence of RNA interference (RNAi)-mediated off-target gene modulation, little is known about whether these changes induce observable phenotypic outcomes. Here we show that a fraction of randomly selected small inhibitory RNAs (siRNAs) can induce changes in cell viability in a target-independent fashion. The observed toxicity requires an intact RNAi pathway and can be eliminated by the addition of chemical modifications that reduce off-target effects. Furthermore, an analysis of toxic and nontoxic duplexes identifies a strong correlation between the toxicity and the presence of a 4-base-pair motif (UGGC) in the RISC-entering strand of toxic siRNA. This article provides further evidence of siRNA-induced off-target effects generating a measurable phenotype and also provides an example of how such undesirable phenotypes can be mitigated by addition of chemical modifications to the siRNA.
Fedorov
Yuriy
Y
Dharmacon Research, Lafayette, CO 80026, USA. fedorov@dharmacon.com
Anderson
Emily M
EM
Birmingham
Amanda
A
Reynolds
Angela
A
Karpilow
Jon
J
Robinson
Kathryn
K
Leake
Devin
D
Marshall
William S
WS
Khvorova
Anastasia
A