Fig. 4.

miRNA-mediated mechanism of gene expression regulation in human cells. Mature miRISC binds miRNA target sites localized I mostly within the 3′UTR but also (indicated in orange) II in the 5′UTR or III in the CDS. There are two main pathways of miRNA-mediated mechanisms of gene expression regulation: a translation inhibition either on initiation (1, 2) or at a post-initiation step (3–5) and b deadenylation followed by c decapping and d, e mRNA decay. However, some less well-known alternatives, indicated by dashed orange lines, have been described: f translation upregulation, g import into the nucleus and h alternative splicing modulation, i decapping followed by translation inhibition and j deadenylation followed by translation inhibition. See text for more details