ABSTRACT
The expression of gene can be silenced in a highly specic and effective way via the RNA interference (RNAi) pathway, a sequence-specic post-transcriptional gene silencing mechanism that occurs intracellularly to degrade target mRNA and regulates endogenous RNA level.1 Fire and Mello were awarded the Nobel Prize in physiology in 2006 for their discovery of RNAi pathway. RNAi pathway could be triggered by introducing the molecule of chemically synthesized 21-23 bp small interfering RNA (siRNA). siRNA is assembled into the RNA-induced silencing complex (RISC) and cleaved upon activation of RISC in cytoplasm of target cells. In the activated RISC, the sense strand is removed and degraded by nucleases, whereas the antisense strand guides the RISC to the base-complementary sequence of the target mRNA and induces the degradation of complementary mRNA and eventually downregulates the target gene expression.2
