RESUMO
RNA interference (RNAi), i.e. gene silencing, or gene expression down-regulation is the process whereby a double-stranded RNA (dsRNA) induces the homology-dependent degradation of cognate messenger RNA (mRNA). When dsRNA is introduced into cells, an RNA-induced silencing complex (RISC) is assembled. RISC serves as cellular machinery that is responsible for the specific mRNA degradation. This process results in the subsequent reduction of the specific protein translated from appropriate mRNA. Short RNA duplexes (21 nucleotide), called small interfering RNA (siRNA), have become the major tool for induction of gene silencing. With the human genome mapped and sequenced, attempts are currently being made to manipulate the expression of genes involved in viral diseases, carcinogenesis and other disorders with the aim of developing novel therapies.