FIGURE 2.

miRISC-mediated gene repression and the influence from RBPs. While there are conflicting models of miRISC-mediated gene silencing that are not mutually exclusive, scientists have agreed upon a “default” mechanism as all the proposed mechanisms for miRNA-mediated repression involve repression of translation and mRNA decay. As shown in (A), Ago interacts with the PABP complex to promote mRNA deadenylation through recruitment of poly(A) nuclease deadenylation complex subunit 2 (PAN2)-PAN3 and carbon catabolite repressor protein 4 (CCR4)-NOT. Deadenylation promotes decapping by the mRNA-decapping enzyme subunit DCP1-DCP2, making the mRNA vulnerable to degradation by exoribonuclease 1 (XRN1). (B) Highlights the influence RBP binding in the 3′UTR can have on miRISC-mediated gene repression. The RBP can bind up or downstream of the miRISC and either enhance the repression, usually through increasing mRNA degradation, or it could reduce the silencing efficiency of the miRISC.