Global analysis of microRNA target gene expression reveals the potential roles of microRNAs in maintaining tissue identity

Background  

MicroRNAs are non-coding small RNAs of ~22 nucleotides that regulate the gene expression by base-paring with target mRNAs, leading to mRNA cleavage or translational repression. It is currently estimated that microRNAs account for ~ 1% of predicted genes in higher eukaryotic genomes and that up to 30% of genes might be regulated by microRNAs. However, only very few microRNAs have been functionally characterized and the general functions of microRNAs are not globally studied.