Silencing of disease-related genes by small interfering RNAs.

In recent years a new mechanism of posttranscriptional gene silencing has been discovered and named RNA interference. The interference is based on mRNA degradation mediated by small double-stranded RNA molecules approximately 21 nucleotides in length, the so-called short interfering or siRNAs. These molecules are produced from long dsRNAs by Dicer, a dsRNA-specific endonuclease, and cause specific degradation of their mRNA-targets by Watson-Crick base-pairing within a 300 kD multi-enzyme complex named RISC. RNAi is highly conserved between plants and animals of various phyla including mammals. The high sequence-specificity of RNAi makes it a new, promising tool in gene-function analysis as well as in potential therapeutics. In this review the discovery and molecular background of RNAi are summarized and possible fields of application pointed out.