fig1

Figure 1. Exosome formation and miRNA biogenesis. The left section depicts the biogenesis of miRNAs. In the nucleus, pri-miRNAs are transcribed by RNA polymerase II and processed by the Microprocessor complex (Drosha and DGCR8) into pre-miRNAs. These pre-miRNAs are exported to the cytoplasm via Exportin-5 and further processed by Dicer into mature miRNAs. Specific RBPs can recognize sequence motifs on miRNAs (e.g., EXOmotifs) and mediate their selective loading into MVBs. miRNA: MicroRNA; pri-miRNA: primary microRNA; pre-miRNA: precursor microRNA; RBP: RNA-binding protein; MVB: multivesicular body; RNA Pol II: RNA polymerase II; DGCR8: DiGeorge syndrome critical region gene 8; ESCRT: endosomal sorting complex required for transport; ILV: intraluminal vesicle; VAMP7: vesicle-associated membrane protein 7; MHC: major histocompatibility complex.