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. Author manuscript; available in PMC: 2011 Apr 1.
Published in final edited form as: Am J Transplant. 2010 Feb 25;10(4):713–719. doi: 10.1111/j.1600-6143.2010.03032.x

Figure 1. MicroRNA Biogenesis.

Figure 1

Pri-microRNAs are transcribed by RNA polymerase II (Pol II) and then processed in the nucleus into ~70nt stem loop precursors (pre-microRNAs) by RNase III endonuclease Drosha and its partner DGCR8/Parsha. The pre-microRNAs are then transported into the cytoplasm via the nuclear export receptor family member, Exportin5, for further processing into ~22nt small RNA duplexes by the RNase III enzyme Dicer and its partner TRBP. The duplex then separates and the functional miRNA strand is incorporated into the RNA-induced silencing complex (RISC) to either inhibit translation or promote mRNA degradation. Animations that demonstrate miRNA activity can be found at: http:www.nature.com/focus/rnai/animations/index.html and http://www.nature.com/ng/supplements/micrornas/rosetta_video.mpg.