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2001: RNAi Shuts Off Mammalian Genes

Image of a Human Mammary Cell

RNA interference (RNAi) is a mechanism used by cells to protect against invading viruses and transposable genetic elements. The process was first discovered in petunias in the late 1980s. Since then, a flurry of discoveries has followed. RNAi is now one of the hottest topics in biological research.

When an invading double-stranded RNA molecule, such as when a virus enters the cell, it is recognized and cut into short 21-23 base snippets of RNA. The small RNA molecules form complexes with proteins. These complexes can target mRNA molecules that have the same sequences and cleave them, thus silencing that particular gene.

For the first time, scientists have demonstrated that doubled-stranded RNA molecules can be introduced into mammalian cells and used to silence targeted genes. Eventually, scientists hope to use RNAi to treat diseases caused by the expression of a viral gene or by the inappropriate expression of a human gene.


More Information


Elbashir, S.M., Harborth, J., Lendeckel, W., Yalcin, A., Weber, K., Tuschl, T. Duplexes of 21-nucleotide RNAs mediate RNA interference in cultured mammalian cells. Nature, 411: 494-498. 2001. [PubMed]


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Last Reviewed: July 29, 2013