A universal, benchtop, gel-free method for the rapid and simultaneous isolation of all known classes of functional small RNAs

All known silencing small (s)RNAs operate via ARGONAUTE(AGO)-family proteins within RNA-induced-silencing-complexes (RISCs). Based on AGOs conserved biochemical properties, we have developed a universal, 15-min benchtop extraction procedure allowing simultaneous purification of all classes of RISC-associated sRNAs known to date, without prior knowledge of the samples-intrinsic AGO repertoires. Optimized into a user-friendly kit, the method –coined “TraPR” for Trans-kingdom, rapid, affordable Purification of RISCs– operates irrespectively of the organism, tissue, cell type or bio-fluid of interest, including from minute amounts of input material. The method is highly suited for direct sRNA deep-sequencing, with TrAPR-generated libraries being qualitatively and quantitatively at least on-par with those obtained via gold-standard procedures involving tedious polyacrylamide gel excisions. TraPR considerably improves the quality and consistency of sRNA sample preparation including from notoriously difficult-to-handle tissues/bio-fluids such as starchy storage roots and mammalian plasma, and regardless of RNA contaminants or samples' RNA-degradation status. Overall design: Trans-kingdom, rapid, affordable Purification of RISC (TraPR) protocol for sRNA isolation was compared to standard sRNA library preparation from total RNA. A variety of source tissue, like Arabidopsis flower buds, Drosophila ovaries and mouse livers and plasa were used for these comaparisons.