RNA Interference Mechanisms in Gene Regulation

RNA interference (RNAi) is a conserved post-transcriptional gene regulatory pathway whereby short non-coding RNAs guide silencing complexes to complementary messenger RNAs, resulting in translational repression or transcript degradation. The biogenesis of RNAi effectors involves the RNase III enzyme Dicer, which processes double-stranded RNA precursors into ~21–24 nucleotide duplexes, yielding microRNAs (miRNAs) and small interfering RNAs (siRNAs). These duplexes are loaded into Argonaute proteins within the RNA-induced silencing complex (RISC), which selects one guide strand for sequence-specific target recognition. Co-factors such as TRBP and PACT modulate Dicer substrate selectivity and processing kinetics, while structural features of precursor RNAs—including terminal loops and internal motifs—influence cleavage patterns. Beyond canonical cytoplasmic silencing, non-canonical pathways involve nuclear or damage-induced Dicer activities, as well as Ago2-mediated processing of select precursors. Together, these mechanisms orchestrate diverse biological processes, from development and immune defence to genome stability and disease. Understanding the interplay of enzymatic components, RNA structures and accessory proteins has underpinned global efforts to harness RNAi for therapeutics, functional genomics and crop improvement.

Research from Nature Portfolio

Mutational analyses of the RNase III domains of Dicer in cancer have revealed that alterations in both IIIa and IIIb domains perturb the balance of 5′ and 3′ arm processing of pre-miRNAs, leading to depletion of specific miRNA families and dysregulation of target gene networks in endometrial tumours. Structural coupling between domains rationalises how IIIa mutations phenocopy known IIIb hotspots, providing insight into mechanistic links between Dicer architecture and miRNA strand selection. Separately, single-molecule fluorescence studies have shown that TRBP acts as a gatekeeper in RNA-crowded environments, selectively delivering bona fide pre-miRNAs to Dicer by discriminating against similar substrates. TRBP’s interaction with the PAZ domain of Dicer and its own RNA-binding dynamics ensure efficient turnover and fidelity of miRNA biogenesis under competitive intracellular conditions.

RNA Interference Mechanisms in Gene Regulation publication trend

The graph below shows the total number of articles in rna interference mechanisms in gene regulation across all publications each year (not limited to Nature Index journals).

Technical terms

RNA interference (RNAi): A cellular mechanism in which small non-coding RNAs guide effector complexes to complementary mRNAs, resulting in gene silencing.

microRNA (miRNA): Endogenous ~22 nucleotide RNA guides produced by Dicer that mediate post-transcriptional regulation via RISC.

small interfering RNA (siRNA): Exogenous or endogenous ~21–24 nucleotide RNAs derived from long double-stranded precursors that direct target mRNA cleavage.

Dicer: An RNase III enzyme that cleaves double-stranded RNA precursors into miRNA and siRNA duplexes.

RNA-induced silencing complex (RISC): A multi-protein assembly, centred on Argonaute, that uses guide RNAs to recognise and silence target transcripts.

Trans-activation response RNA-binding protein (TRBP): A Dicer-associated protein that enhances substrate specificity and processing efficiency in miRNA biogenesis.

References

1. Cancer-associated mutations in DICER1 RNase IIIa and IIIb domains exert similar effects on miRNA biogenesis. Nature Communications (2019).
2. TRBP ensures efficient Dicer processing of precursor microRNA in RNA-crowded environments. Nature Communications (2016).
3. Two-motif model illuminates DICER cleavage preferences. Nucleic Acids Research (2024).
4. Structure of pre-miR-31 reveals an active role in Dicer–TRBP complex processing. Proceedings of the National Academy of Sciences of the United States of America (2023).
5. Differential roles of human Dicer-binding proteins TRBP and PACT in small RNA processing. Nucleic Acids Research (2013).
6. Nuclear phosphorylated Dicer processes double-stranded RNA in response to DNA damage. Journal of Cell Biology (2017).
7. Poly(A)-Specific Ribonuclease Mediates 3′-End Trimming of Argonaute2-Cleaved Precursor MicroRNAs. Cell Reports (2013).