Guidelines on Designing MicroRNA Sponges: From Construction to Stable Cell Line.

Single microRNA (miRNA) can be inhibited using antagomiR which efficiently knockdown a specific miRNA. However, the effect is transient and often results in subtle phenotype. Here we report a guideline on designing miRNA sponge inhibiting a miRNA family. As a model system, we targeted miR-30 family, known as tumor suppressor miRNAs in multiple tumors. To achieve an efficient knockdown, we generated perfect and bulged-matched miRNA binding sites (MBS) and introduced multiple copies of MBS. The protocol here demonstrates the miRNA sponge as a useful tool to examine the functional impact of inhibition miRNAs.