miRNA binding site for gene knock down?

In higher eukaryotes a class of small RNAs knows as micro RNA (miRNA) that mediates the silencing of paicular genes. The RNAs function by interacting with mRNAs, often in the 3' Untranslated region, resulting in either mRNA degradation or translation inhibition. In either case, the mRNA, and thus the gene that produces it, is silenced. The process is known as RNA interference. miRNAs: MicroRNAs, 21 to 22 nucleotide long RNA species derived primarily from RNA polymerase II transcription units, RNA processing. These RNAs play crucial roles in gene regulation by altering mRNA function.