© 2004 by Oxford University Press
Mouse microRNA-23b regulates expression of Hes1 gene in P19 cells
1 Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan, 2 Gene Function Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba Science City 305-8562, Japan
MicroRNAs (miRNAs) are abundant class of 
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 embryo-genesis, 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 diffrentiation, is a target of mouse miRNA-23b (miR-23b).