RNA干渉

In RNAi, small double-stranded RNAs suppress expression of a target protein by stimulating the specific degradation of the complementary target mRNA. RNAi is a powerful technique that allows researchers to investigate gene function by knocking out or knocking down the level of a particular protein. RNAi is a multistep process in which the dsRNA is recognized by an RNase III family member (e.g., Dicer in Drosophila) and is cleaved into siRNAs of 21–23 nucleotides. The siRNAs are incorporated into an RNAi targeting complex known as RISC (RNA-induced silencing complex), which destroys mRNAs homologous to the siRNA contained in the complex, effectively knocking out protein expression.

MicroRNAs (miRNAs) are short, noncoding RNAs that regulate gene expression. miRNAs target the 3´-untranslated region of messenger RNA sequences, affect RNA stability and prevent translation. miRNAs have been implicated them in a wide range of biological processes and disease states including development, metabolism, and cancer.