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

Other messenger RNAs with seed-region complementarity refers to the broad set of unintended transcripts targeted by RNA interference (RNAi) therapeutics, such as siRNAs or miRNA mimics (Jackson et al., 2003, Nature Biotechnology). This phenomenon occurs when the 'seed region'—typically nucleotides 2 through 8 of the small RNA guide strand—finds a complementary match in the 3' untranslated region (UTR) of a non-target mRNA (Birmingham et al., 2006, Nature Methods). Because this binding mimics the natural regulatory mechanism of endogenous microRNAs, it can lead to the degradation or translational repression of hundreds of unintended genes (Filipowicz et al., 2008, Nature Reviews Genetics). In drug discovery, these off-target effects are a significant hurdle, as they can cause cellular toxicity or lead to false-positive results in functional screens (Burchard et al., 2009, Nature Biotechnology). Modern therapeutic design employs chemical modifications, such as 2'-O-methyl substitutions on the ribose ring, and advanced bioinformatic filtering to minimize these interactions and improve the safety profile of RNA-based drugs (Janas et al., 2018, Nature Communications). Consequently, this 'target' is actually a primary source of toxicity that must be avoided rather than a therapeutic objective.

Other names

Off-target transcriptsSeed-matched off-targetsmiRNA-like off-targetssiRNA off-target effects

Unintended binding of the siRNA or miRNA seed region (nucleotides 2-8) to complementary sequences in the 3' untranslated regions (UTRs) of non-target mRNAs, leading to gene silencing via the RNA-induced silencing complex (RISC).