How Can Double-Stranded RNA (dsRNA) Stop Gene Activity?
Double-stranded RNA can be introduced into a cell by artificial means, for example through the aid of a virus invading the cell. Once inside, dsRNA is cleaved by a Dicer enzyme into short interfering RNA segments (siRNA). Then another enzyme binds to each of these siRNAs to form the RNA induced silencing complex or the Risc complex. This complex then goes to work to put the brakes on protein production. It cuts the messenger RNA (mRNA) so that it becomes unstable, breaks and degrades and so translation cannot take place. The whole process of gene silencing is also called the post-transcriptional gene silencing (PTGS) because it happens after the DNA is transcribed to mRNA.
