Dicer [SEP] found in taxon
, the epigenetic silencing of genes by miRNAs, was discovered.
In terms of crystal structure, the first Dicer to be explored was that from the protozoan "Giardia intestinalis". A PAZ domain and two RNase III domains were discovered by X-ray crystallography. The protein size is 82 kDa, while it is larger in other organisms; for example, it is 219 kDa in humans. The difference in size from humans to "G. intestinalis" Dicer is due to at least five different domains being present within human
enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]