Dicer
![One molecule of the Dicer protein from Giardia intestinalis, which catalyzes the cleavage of dsRNA to siRNAs. The RNase III domains are colored green, the PAZ domain yellow, the platform domain red, and the connector helix blue.[5]](/uploads/202501/08/2ffl-by-domain3341.png)
![The enzyme dicer trims double stranded RNA, to form small interfering RNA or microRNA. These processed RNAs are incorporated into the RNA-induced silencing complex (RISC), which targets messenger RNA to prevent translation.[10]](/uploads/202501/08/RNAi-simplified3341.png)
Dicer, also known as endoribonuclease Dicer or helicase with RNase motif, is an enzyme that in humans is encoded by the DICER1 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. These fragments are approximately 20-25 base pairs long with a two-base overhang on the 3' end. 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).