MicroRNAs in search of a target.

As the number of known microRNAs (miRNAs) increases, and their importance in physiology and disease becomes apparent, the identification of their regulatory targets is a requisite for a full characterization of their biological functions. Computational methods based on sequence homology and phylogenetic conservation have spearheaded this effort in the last 3 years, but they may not be sufficient. Experimental studies are now needed to extend and validate the computational predictions and further our understanding of target recognition by miRNAs.