Off-target messenger RNAs (seed-region complementarity) (Off-target mRNAs)

Off-target messenger RNAs (mRNAs) with seed-region complementarity refer to the collection of cellular transcripts that are unintentionally silenced during RNA interference (RNAi) experiments or therapies. This phenomenon occurs when the "seed region" of an shRNA or siRNA guide strand—typically nucleotides 2 through 8—binds to complementary sequences in the 3' untranslated regions (UTRs) of non-target mRNAs (Jackson et al., 2003). This interaction mimics the natural regulatory mechanism of microRNAs (miRNAs), leading to unintended mRNA degradation or translational inhibition (Birmingham et al., 2006). These off-target effects are a major concern in drug development as they can cause significant cytotoxicity, alter cellular phenotypes, and lead to false-positive results in functional genomics screens (Fedorov et al., 2006). In clinical settings, high levels of off-target silencing have been linked to organ toxicity, particularly in the liver, and can even result in lethality in animal models due to the saturation of the endogenous RNAi machinery (Grimm et al., 2006). Strategies to mitigate these effects include chemical modifications of the guide strand, such as 2'-O-methyl groups, and advanced computational algorithms to design sequences with minimal seed-region matches across the human transcriptome.

Other names

Seed-mediated off-targetsshRNA off-target effectssiRNA off-target effectsmiRNA-like off-target silencingTranscriptome-wide off-targets

Unintended gene silencing via seed-region (nucleotides 2-8) complementarity to the 3' UTR of non-target mRNAs, mimicking the microRNA pathway (Jackson et al., 2003; Birmingham et al., 2006).