Fig. 1: The miRNA biogenesis pathway.

MiRNA genes are transcribed by RNA Pol II to produce pri-miRNAs. The pre-miRNA, is transported to the cytoplasm via the Exportin-5/RanGTP complex and is transported into the cytoplasm. Next, miRNA double-stranded bodies are produced by Dicer. After double-strand unwinding by the unwinding enzyme activity of Dicer, one strand will be degraded while the other strand is retained and eventually forms RISC. The miRISC containing the catalytic component of Argonaute proteins recognizes the complementary sequences that do not exactly match in its target and leads to translation inhibition or accelerated transcript degradation by uncapping and deadenylation.