saRNAs  (小激活RNA)

RNA activation (RNAa) is a process mediated by RNAs to enhance gene expression. This pathway is mediated by a small activating RNA (saRNA). The saRNA is a class of noncoding RNA composed with a 21-nucleotide dsRNA with 2-nucleotide overhangs at both ends. Indeed, saRNA has an identical structure and chemical components to a small interfering RNA (siRNA) despite their completely opposite biological functions. The key difference between saRNA and siRNA lies at the mechanism of action. Cytosolic saRNA is specifically loaded to an AGO2 protein but not the other AGO variants, unlike siRNA which can bind to AGO1-4 for activity.