The Molecular Basis and Therapeutic Potential of Let-7 MicroRNAs against Colorectal Cancer

Figure 1

A schematic diagram of the let-7 biogenesis. Pri-let-7 microRNA precursors are processed in the nucleus by Drosha to pre-let-7. Pre-let-7 microRNA precursors are exported to the cytoplasm by exportin-5, where they are subsequently processed by Dicer resulting in the mature let-7. RNA binding protein LIN28A or LIN28B binds to either pri-let-7 or pre-let-7 using RNA binding domains, cold shock domain (CSD), and two zinc finger domains (ZFDs) and blocks the processing. Upon binding to pre-let-7, LIN28A or LIN28B recruits TUTase, which causes oligouridylation resulting in the degradation of pre-let-7.