Figure 5.

GW bodies are foci specific to microRNA processing. In this schematic diagram, primary microRNA (pri-miRNA) nuclear transcripts are cleaved by the Drosha–DGCR8 complex into hairpin pre-miRNA, which is exported to the cytoplasm by exportin 5. In the cytoplasm, Dicer is responsible for cleavage of pre-miRNA, generating the mature miRNA. On correct interaction and partnering of the miRNA to messenger RNA containing the miRNA-targeted sequence element ‘X' in the presence of Ago2/RISC (RNA-induced silencing complex), cytoplasmic foci are formed as a result of association of other proteins (see text). However, in the absence or low levels of miRNA, as a result of Drosha or DGCR8 protein knockdown, these foci do not form. The transfection of short interference RNA (siRNA) as a surrogate for miRNA leads to the apparent reassembly of GW bodies (GWBs). Ago2, Argonaute 2.