Figure 3.

Methods for gene silencing based on miRNA-triggered secondary siRNAs. (A) Silencing using atasiRNAs consists of replacing one or more of the tasiRNAs in the TAS gene for a sequence designed to target the gene of interest. (B) miRNA-induced gene silencing (MIGS) constructs can be generated by placing the sequence recognized by an miRNA that can start transitivity in front of a fragment of the target gene (e.g., miR173). Downregulation of more than one gene using this technique can be easily accomplished by repeating the same pattern with different gene fragments. (C) By using specific precursors (such as MIR173), 22 nt long amiRNAs can be produced. These molecules can then initiate secondary siRNA synthesis from their targets, adding new features to the original method.