Technique: What is RNA interference?

The central dogma consists of
DNA --> mRNA (via transcription) --> protein (via translation)

RNA interference/RNAi is the silencing of RNA for controlling gene expression. This occurs naturally. Scientists have been able to use RNAi as a tool for studying gene expression, drug target screening, and for development of therapeutic drugs. 

1. Double stranded RNA is cleaved into small interfering RNA/siRNA by the RNAseIII enzyme called Dicer.
2. The siRNA are incorporated into silencing complexes that will target messenger RNA/mRNA for cleavage.
3. The mRNA that is coding for a specific protein is degraded, and there won't be any protein expression.

Information was obtained from: http://www.vet.uga.edu/id/tripp/RNAi.php

http://www.vet.uga.edu/id/tripp/RNAi.php

This video was obtained from youtube. The original link for this video is: http://www.nature.com/nrg/multimedia/rnai/animation/index.html

http://www.nature.com/news/2009/090624/images/_tmp_articling-import-20090624083219872961_4591047a-i1.0.jpg

Richard Jorgensen is a molecular geneticist, who is an early pioneer in the study of RNAi. In the 1980s, he was asked to create purple petunias by a biotechnology company. He introduced the gene that coded for the color purple into the plant, and unexpectedly the petunias did not turn purple. A defense mechanism called RNAi was set off, and it deactivated all pigment genes in the plant.

This information was obtained from: http://www.oprah.com/health/RNAi-Based-Treatments-and-Possible-Cures-for-HIV-and-Cancer

Here is a link to the video from Nova: http://www.pbs.org/wgbh/nova/body/rnai.html

A few years after, another group of scientists also noticed this gene silencing effect in C. elegans. Andrew Fire and Craig Mello, were awarded the 2006 Nobel Prize in physiology or medicine for the discovery that RNAi is triggered by double stranded RNA (paraphrased from http://www.nigms.nih.gov/News/Extras/RNAi/factsheet.htm).