Question

What is Dicer? What is its action? What is RISC (RNA induced silencing complex)?

Answer 1

Dicer also known as endoribonuclease Dicer or helicase with RNase motif, is an enzyme that in humans is encoded by the DICER gene. Being part of the RNase III family, Dicer cleaves double-stranded RNA (dsRNA) and pre-microRNA (pre-miRNA) into short double-stranded RNA fragments called small interfering RNA and microRNA, respectively. Dicer facilitates the activation of the RNA-induced silencing complex (RISC), which is essential for RNA interference. RISC has a catalytic component argonaute, which is an endonuclease capable of degrading messenger RNA (mRNA).

The RNA-induced silencing complex, or RISC, is a ribonucleoprotein complex involved in the RNA interference pathway. The pathway scans the cell for mRNA that are viral in nature or ones that have been transcribed from viral DNA and/or transposable elements in the genome. In doing so, the pathway interferes with the translation process of these mRNA molecules, thereby stopping the production of viral proteins that could be harmful to the cell.