RNA interference, also known as RNAi is a biological process in which RNA molecules inhibit gene expression by destructing specific mRNA molecules.
A dsRNA (double stranded RNA) is recognized in the cytoplasm by an enzyme called Dicer that will cut it into double stranded small interfering RNA (siRNA) molecules, which are 20-25 nucleotides long. This siRNA has two strands, one is passenger and the other is the guide. siRNA will bind to RISC(RNA-Induced Silencing Complex) and t will separate the two strands. The passenger strand is degraded, while the guide strand serves as guide for RISC taking it to specific mRNA site complementary to guide strand resulting in cleaving it and hence preventing the production of the unwanted target protein.
|Slide from Prof. Markstein|
RNAi is used to knock genes down and study their functions in cells. It is also used in research as antiviral and caner therapy. Harvard Medical School is studying silencing of hepatitis A and B, herpes simplex virus and host receptors for HIV.
RNA interference is also a promising way to treat cancer by silencing genes involved in cell division.
The power of this technique led to Nobel Prize winner in Physiology or Medicine in 2006 for Andrew Fire and Craig C. Mello ( from UMASS Worcester) who worked on it.
This is RNAi that will make revolution in medicine and be able to cure diseases hopefully.