RNAmediated

RNA-mediated refers to processes in which RNA molecules act as mediators of biological activity, often guiding protein complexes or catalyzing reactions rather than serving only as intermediates. One prominent area is gene regulation, where small RNAs such as siRNAs and miRNAs bind complementary messenger RNAs with the help of Argonaute proteins to suppress translation or trigger degradation. In various contexts, Piwi-interacting RNAs (piRNAs) help protect the genome from transposable elements in germ cells. Long noncoding RNAs can also act as RNA mediators of transcriptional and epigenetic regulation, for example by recruiting chromatin-modifying complexes to specific genomic loci.

In RNA processing, small nuclear RNAs are core components of the spliceosome, guiding the removal of introns from pre-mRNA. Ribozymes demonstrate RNA-mediated catalysis, with enzymes such as RNase P and the catalytic activity of ribosomal RNA.

RNA also underlies adaptive immune strategies in bacteria and archaea through CRISPR-Cas systems, where CRISPR RNAs guide nucleases to invading genetic elements and enable targeted interference.

Overall, RNA-mediated processes illustrate the versatility of RNA molecules as regulators, guides, scaffolds, and enzymes that influence gene expression, genome defense, and cellular function.