miRNAs are initially transcribed as primary miRNAs (pri-miRNAs) in the nucleus. These pri-miRNAs are then processed by the enzyme Drosha to form precursor miRNAs (pre-miRNAs). The pre-miRNAs are transported to the cytoplasm where they are further processed by Dicer, another enzyme, to produce mature miRNAs. The mature miRNAs are then incorporated into the RNA-induced silencing complex (RISC), where they guide the complex to target mRNAs.
