RISCmiRNA

RISCmiRNA refers to microRNAs (miRNAs) that are bound within the RNA-induced silencing complex (RISC). The RISC is a multiprotein complex crucial for gene silencing by small RNAs, including miRNAs. After a miRNA precursor is processed into a mature miRNA, it is loaded into the AGO (Argonaute) protein, which is a key component of the RISC. This loaded RISC then patrols the cytoplasm of the cell, searching for messenger RNA (mRNA) targets that have complementary sequences to the miRNA.

When a RISCmiRNA finds a complementary mRNA target, it can lead to gene silencing through one of two primary mechanisms: translational repression or mRNA degradation. Translational repression occurs when the RISCmiRNA binds to the 3' untranslated region (3' UTR) of the mRNA, preventing ribosomes from translating the mRNA into protein. mRNA degradation happens when the complementarity between the miRNA and its mRNA target is near-perfect, leading to the cleavage and subsequent degradation of the mRNA molecule. The RISCmiRNA is therefore the active agent of post-transcriptional gene regulation mediated by microRNAs. This process plays vital roles in various cellular processes, including development, differentiation, and disease.