First Author | Liu X | Year | 2012 |
Journal | Mol Cell | Volume | 46 |
Issue | 4 | Pages | 507-17 |
PubMed ID | 22503104 | Mgi Jnum | J:188024 |
Mgi Id | MGI:5438907 | Doi | 10.1016/j.molcel.2012.03.010 |
Citation | Liu X, et al. (2012) Precursor microRNA-programmed silencing complex assembly pathways in mammals. Mol Cell 46(4):507-17 |
abstractText | Assembly of microRNA ribonucleoproteins (miRNPs) or RNA-induced silencing complexes (RISCs) is essential for the function of miRNAs and initiates from processing of precursor miRNAs (pre-miRNAs) by Dicer or by Ago2. Here, we report an in vitro miRNP/RISC assembly assay programmed by pre-miRNAs from mammalian cell lysates. Combining in vivo studies in Dicer Knockout cells reconstituted with wild-type or catalytically inactive Dicer, we find that the miRNA loading complex (miRLC) is the primary machinery linking pre-miRNA processing to miRNA loading. We show that a miRNA precursor deposit complex (miPDC) plays a crucial role in Dicer-independent miRNA biogenesis and promotes miRNP assembly of certain Dicer-dependent miRNAs. Furthermore, we find that 5'-uridine, 3'-mid base pairing, and 5'-mid mismatches within pre-miRNAs promote their assembly into miPDC. Our studies provide a comprehensive view of miRNP/RISC assembly pathways in mammals, and our assay provides a versatile platform for further mechanistic dissection of such pathways in mammals. |