Mouse microRNA-23b regulates expression of Hes1 gene in P19 cells.

MicroRNAs (miRNAs) are abundant class of approximately 21-25 nts small endogenous RNAs. Recently several hundred miRNAs have been identified from diverse species; nematodes, insects, plants, and animals. These small RNAs can regulate gene expression at a post-transcriptional level by interacting with their target mRNAs. Interaction of these RNAs causes either repression of translation or RNAi-dependent cleavage of target RNAs. It has been recently found that they have critical regulatory roles in embryogenesis, development, differentiation, cellular proliferation, apoptosis, and so on. However, identifications of the target of the target of miRNAs have been almost unknown, especially in vertebrates. Here we show that Hairy/enhancer of split protein (Hes1), a bHLH transcriptional repressor functioning in neuronal differentiation, is a target of mouse miRNA-23b (miR-23b).