Interference RNA -part 2

structure of RNAi

Historically, RNA interference was known by other names, including post transcriptional gene silencing, transgene silencing, and quelling. Only after these apparently-unrelated processes were fully understood did it become clear that they all described the RNAi phenomenon. RNAi has also been confused with antisense suppression of gene expression, which does not act catalytically to degrade mRNA, but instead involves single-stranded RNA fragments physically binding to mRNA and blocking protein translation.

Advantages of RNAi
1. The ability to harness a natural pathway: RNAi is a natural pathway to control gene expression. This natural pathway can be harnessed to create a new class of innovative medicines.
2. The ability to target virtually any protein: A key limitation of traditional medicinesis that they can only target certain classes of protein. In contrast, siRNAs can be designed for any kind of protein and thus targetable for every proteins.
3. Acting 'upstream' of today's medicines: With RNAi therapeutics, it is possible to block the production of disease causing proteins before they are made. This affords the opportunity to provide greater efficacy in disease control and intervention.
4. RNAi drug candidates can be identified easily using bioinformatic tools to select sequences complementary to the target mRNA in contrast to the extensive lead optimization steps required in normal drugs.

The selective and robust effect of RNAi on gene expression makes it a valuable research tool, both in cell culture and in living organisms because synthetic dsRNA introduced into cells can induce suppression of specific genes of interest. RNAi may also be used for large-scale screens that systematically shut down each gene in the cell, which can help identify the components necessary for a particular cellular process or an event such as cell division. Exploitation of the pathway is also a promising tool in biotechnology and medicine.