Multi-miRNA hairpin method that improves gene knockdown efficiency and provides linked multi-gene knockdown.

A number of natural microRNA (miRNA) hairpins have been found in clusters of multiple identical or different copies, suggesting that effects of miRNAs can be enhanced and multiple genes can be regulated together by encoding multiple miRNA hairpins in a single transcript. Here, we report a simple and effective artificial multi-hairpin method that stimulates production of mature 22-nucleotide small RNAs from modified miRNA hairpins, improves gene knockdown over single-hairpin constructs, and provides linked multi-gene knockdowns.