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Expression profiling reveals off-target gene regulation by RNAi.
Aimee L Jackson1, Steven R Bartz, Janell Schelter
1Rosetta Inpharmatics LLC, 12040 115th Avenue NE, Kirkland, Washington 98034, USA. aimee_jackson@merck.com
Nature Biotechnology
|May 20, 2003
Summary
Small interfering RNAs (siRNAs) can silence genes with limited sequence similarity, not just near-identical targets. This cross-reactivity means siRNAs may affect unintended genes, impacting RNA interference specificity.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- RNA interference (RNAi) is a gene silencing mechanism.
- Small interfering RNAs (siRNAs) mediate RNAi by binding to target messenger RNAs (mRNAs).
- Current understanding suggests siRNAs require near-identity to their mRNA targets for effective silencing.
Purpose of the Study:
- To investigate the specificity of gene silencing mediated by siRNAs.
- To characterize the transcriptomic signatures associated with siRNA activity.
- To determine the minimum sequence similarity required for siRNA-mediated gene silencing.
Main Methods:
- Gene expression profiling using transcriptomics.
- Cultured human cells treated with siRNAs.
- Analysis of transcript profiles to identify gene silencing patterns.
Main Results:
- Observed siRNA-specific signatures in gene expression, not solely target-specific.
- Demonstrated direct silencing of non-targeted genes.
- Identified genes with as few as eleven contiguous nucleotides of identity to the siRNA were silenced.
Conclusions:
- siRNAs exhibit cross-reactivity with targets possessing limited sequence similarity.
- The specificity of siRNA gene silencing may be broader than previously assumed.
- Findings highlight potential off-target effects in siRNA applications.