A large fraction of mammalian genome can be transcribed to produce various RNAs, of which only a small subset can serve as the template for protein translation. The RNAs that do not code for proteins are collectively referred as non-coding RNA, which can serve as key functional components or regulatory molecules of gene expression. The best understood regulatory non-coding RNAs include microRNAs (miRNAs) that control degradation and/or translation of mRNAs and long non-coding RNAs (lncRNAs) that often control chromatin structure and gene transcription. Depending on the specific targets regulated by non-coding RNAs, the biological roles of the regulatory non-coding RNA can be very diverse. In...