Gene silencing by double-stranded RNA.
Eukaryotes silence gene expression in the presence of double-stranded RNA homologous to the silenced gene. Silencing occurs by the targeted degradation of mRNA. Biochemical reactions that recapitulate this phenomenon generate RNA fragments of 21--23 nucleotides from the double-stranded RNA. These stably associate with an RNA endonuclease and probably serve as a discriminator to select mRNAs. Once selected, mRNAs are cleaved at sites 21--23 nucleotides apart. This mechanism, termed RNAi, has functional links to viral defense and silencing phenomena, such as cosuppression. It also functions to repress the hopping of transposable elements.
Carthew
R W
RW
Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA. carthew+@pitt.edu
D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000235:genetics; D004330:Drosophila / Q000187:drug effects / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D020868:Gene Silencing; D010944:Plants / Q000187:drug effects / Q000235:genetics; D012330:RNA, Double-Stranded / Q000235:genetics* / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics
D012330:RNA, Double-Stranded; D012333:RNA, Messenger