The RNAi pathway begins with the introduction of double-stranded RNA (dsRNA) into the cell. This dsRNA is then processed by an enzyme called Dicer into small interfering RNA (siRNA) or microRNA (miRNA). These small RNA molecules are incorporated into the RNA-induced silencing complex (RISC). The RISC uses one strand of the siRNA or miRNA as a guide to find and degrade complementary mRNA, thereby preventing it from being translated into proteins.
