Figures & data
Figure 1. MicroRNA (miRNA) biogenesis. The transcription of miRNA genes by RNA polymerase II (Pol II) results in primary miRNA transcripts (pri-miRNAs), which are then cleaved in the nucleus by a complex of Drosha and DGCR8. The resulting precursor miRNA hairpin (pre-miRNA) is exported into the cytosol in an exportin-5-dependent pathway and further processed by the RNase dicer to an intermediate miRNA duplex. The leading strand is then loaded into the (mi)RNA-induced silencing complex (mi)RISC, whereas the second strand subjected to degradation. The strand selection depends on the thermodynamic characteristics of the miRNA duplex. The (mi)RISC complex is guided to target mRNAs sequences that are located within the 3′ untranslated regions (3′UTRs) of the mRNA. Following these reactions, the mRNA is targeted by translational repression and/or degradation.
