RNA-Induced Silencing Complex (RISC). Computer model showing the molecular structure of a bacterial argonaute protein (red) bound to a small interfering RNA (siRNA) molecule (green and purple, bottom left). RISC is the multiprotein complex responsible for the gene silencing phenomenon known as RNA interference (RNAi). It incorporates one strand of siRNA, which it uses as a template for recognising complementary mRNA (messenger RNA), and an argonaute protein that catalyses the RNA interference process.