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Gene silencing by double-stranded RNA
1Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA. carthew+@pitt.edu
Current Opinion in Cell Biology
|March 15, 2001
Summary
Gene silencing in eukaryotes involves targeted mRNA degradation triggered by double-stranded RNA. This process, known as RNA interference (RNAi), utilizes small RNA fragments to guide an enzyme that cleaves specific messenger RNAs.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Eukaryotes possess a mechanism to silence gene expression when encountering double-stranded RNA (dsRNA) homologous to a target gene.
- This gene silencing is primarily achieved through the specific degradation of messenger RNA (mRNA).
Purpose of the Study:
- To elucidate the biochemical mechanism underlying dsRNA-induced gene silencing in eukaryotes.
- To identify the key molecular players and intermediates involved in this process.
Main Methods:
- Biochemical assays were employed to replicate the gene silencing phenomenon in vitro.
- Analysis of RNA fragments generated from dsRNA and their association with cellular components.
Main Results:
- Double-stranded RNA is processed into small RNA fragments of 21--23 nucleotides.
- These small RNA fragments associate with an RNA endonuclease, acting as a guide for mRNA targeting.
- Targeted mRNA molecules are cleaved at specific sites, spaced 21--23 nucleotides apart.
Conclusions:
- The described mechanism, termed RNA interference (RNAi), is a conserved biological process in eukaryotes.
- RNAi plays roles in antiviral defense, gene cosuppression, and the regulation of transposable elements.