Detection of MicroRNAs Released from Argonautes

The Argonaute (AGO) family of proteins plays an essential role in the process of microRNA (miRNA)-mediated gene silencing. More specifically, they are the only known proteins to associate directly with miRNAs within the RNA-induced silencing complex (RISC). Given the importance of miRNA regulation of the transcriptome and its vast implications for human disease, it is essential to understand the molecular underpinnings of miRNA-AGO interactions. Although there are methods available to investigate mature miRNA decay and loading onto AGO2, no feasible method exists to detail the opposite process: release of miRNA from associated AGO proteins. In this chapter, we describe in detail a methodology derived from biochemical approaches, which can be used to quantify the release of any given miRNA from AGOs.