Dicer Pathway
The degradation of endogenous mRNA in a sequence-specific manner can be induced by dsRNA [RNA interfernce (RNAi)], antisense transcription, or viral infection. In the current model for posttranscriptional gene silencing by RNAi, the ribonuclease III like enzyme Dicer processes dsRNA into small fragments (siRNA) of 21-25 nts. The siRNA is incorporated into the RNA-induced silencing complex (RISC), which targets and degrades the homologous mRNA. Most of the proteins in the RISC (with the exception of Ago2 and Dicer have not been identified) but likely contain endonuclease, helicase, exonuclease and homology scanning activity.
Contributor: Joseph Chuang, PhD
REFERENCES: Doi N et al. Short-Interfering-RNA-Mediated Gene Silencing in Mammalian Cells Requires Dicer and eIF2C Translation Initiation Factors. Curr Biol. 2003 Jan 8;13(1):41-6. Hannon GJ. RNA interference. Nature. 2002 Jul 11;418(6894):244-51. Review. Scherr M et al. Gene silencing mediated by small interfering RNAs in mammalian cells. Curr Med Chem. 2003 Feb;10(3):245-56. Review.
