Abstract
RNA interference (RNAi) is a form of posttranscriptional gene silencing mediated by microRNA (miRNA) and small interfering RNA (siRNA). In Drosophila melanogaster, the RNase III enzymes Dicer-1 and Dicer-2 generate miRNA and siRNA, respectively. We describe the methods for the expression, purification, and analysis of recombinant Dicer-1 and Dicer-2 enzymes. Our studies demonstrate that Dicer-1 and Dicer-2 display different substrate specificities and ATP requirements.