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Genetic Information
Eukaryotes
RNA Interference (RNAi)
Post-transcriptional gene silencing by small interfering RNAs.
Overview
RNAi is triggered by double-stranded RNA (dsRNA) processed by Dicer into small interfering RNAs (siRNAs, ~21 nt). siRNAs are loaded into the RISC complex where the guide strand directs sequence-specific mRNA cleavage by Argonaute proteins. MicroRNAs (miRNAs) use a similar mechanism but typically cause translational repression rather than cleavage. This pathway serves as an antiviral defense and gene regulatory mechanism.
Cellular Location
Cytoplasm (processing), P-bodies
Clinical Significance
Nobel Prize 2006 (Fire & Mello); therapeutic RNAi drugs (patisiran for hTTR amyloidosis); miRNAs regulate ~60% of human genes; CRISPR evolved from related defense systems.