Figure 2.

General overview of an in vitro selection using Systematic Evolution of Ligands by EXponential enrichment (SELEX). Each round proceeds in four main steps. A gene library is in vitro transcribed (Step 1) and mixed with beads displaying the fluorogen. Poor binders are eliminated by wash of variable stringency (selection pressure, Step 2) prior to recovering binding RNAs during the elution step (Step 3). Finally, RNAs are converted into cDNAs (Step 4), later used to prime a new round of selection.