Figure 1: Biogenesis of miRNA. miRNAs are transcribed into pri-miRNA and are capped and polyadenylated. This pri-miRNA is processed by Drosha and DGCR8 into pre-miRNA, which by Ran-GTP and Exportin-5 are transported into the cytoplasm and further processed by Dicer. The miRNA dissociates and with help of RISC gets involved in gene silencing by translation repression or degradation of target mRNA.