Fig. 3
From: Role of non-coding RNA networks in leukemia progression, metastasis and drug resistance
MicroRNA (miRNA) biogenesis and regulation of gene expression. The series of events includes the production of the primary miRNA (pri-miRNA) transcript by RNA polymerase II or III and cleavage of the pri-miRNA into a stem-loop structured miRNA precursor (pre-miRNA) by the microprocessor complex Drosha-DGCR8 (Pasha) in the nucleus. Then the pre-miRNA hairpin is exported from the nucleus by Exportin-5-Ran-GTP. In the cytoplasm, the RNase Dicer in complex with the double-stranded RNA-binding protein TRBP cleaves the pre-miRNA hairpin to its mature length. The functional strand of the mature miRNA is loaded together with Argonaute (Ago2) proteins into the RNA-induced silencing complex (RISC), where it guides the RISC to silence target mRNAs through mRNA cleavage, translational repression or deadenylation, whereas the passenger strand is degraded