Standard pathway by which microRNAs are processed and loaded onto RISC to regulate gene expression. Regulation of microRNA (miRNA) expression is controlled at the miRNA promoter by transcription factors (TF) and nuclear receptors (NR). After transcription, the pri-miRNA is processed inside the nucleus by Drosha and DGCR8 to form pre-miRNA – a hairpin miRNA. Exportin 5 exports the pre-miRNA from the nucleus into the cytoplasm where it gets cleaved further by Dicer, resulting in a short double-strand piece of RNA. These strands are separated into the passenger strand, which often gets degraded, and the mature strand, which is loaded onto RNA-induced silencing complex (RISC) for action on target mRNA. If the seed sequence (base pairs 2 to 7) of the mature miRNA is complementary to the mRNA, the transcript is degraded. However, if there is not perfect complementarity between the miRNA seed sequence and its target mRNA, the result is inhibition of translation. DGCR8, DiGeorge syndrome chromosomal region 8.