MiRNA in bladder carcinogenesis: A review

Figure 2 Micro RNA biogenesis in human cells. After transcription by RNA polymerase II, the primary micro RNA (miRNA) precursor (Pri-miRNA) is cleaved by Drosha microprocessor complex and converted in Pre-miRNA, a 60-70 nt double-strand molecule. The Pre-miRNA is transported from nucleus to the cytoplasm by Exportin-5 and then it is cleaved by Dicer to generate the miRNA duplex. Again, Dicer enzyme acts over miRNA duplex and produces single-strand mature miRNA that, in turn, is incorporated into RNA-Induced Silencing Complex (RISC). RISC drivers mature miRNA to the target messenger RNA (mRNA), triggering mRNA cleavage (Slicer activity) or inhibition of translation by complete or incomplete complementarity, respectively.