Fig. (2). Nuclear Export of pre-miRNAs a Key Step in Biogenesis Process.
Precursor miRNAs (pre-miRNA) are exported from the nucleus with the aid of specialized protein exporters [primarily by exportin 5 (XPO5) and to a less extent exportin 1 (XPO1)]. Nuclear export begins with the binding of pre-miRNA to XPO5 in a RanGTP dependent manner. Once the pre-miRNA is exported to the cytoplasm, the RanGTP coverts to GDP bringing conformational change in the XPO5 resulting in the release of pre-miRNA from the XPO5 structure. (The color version of the figure is available in the electronic copy of the article).