Fig. 3.

Representing sorting mechanism of miRNAs into exosomes. miRNA genes are transcribed by RNA polymerase II into primary miRNAs (pri-miRNAs), which are then processed by Drosha complex into precursor miRNAs (pre-miRNAs), which are then exported into cytoplasm by the exportin 5 complex. Pre-miRNAs are then processed by the Dicer complex into mature miRNAs, which are further sorted into exosomes through four potential pathways namely: a nSMase2- dependent pathway; b 3′ end miRNA sequence-dependent pathway; c Sumoylated hnRNPs- dependent pathway; d miRISC related pathway. Exosomal miRNAs perform a functional role after being transported into recipient cells