Small RNAs – their biogenesis, regulation and function in embryonic stem cells

Excerpt

Mammalian development follows a carefully orchestrated unfolding of cell fate decisions whose time, place, and specialization must occur robustly and consistently to end with a healthy adult organism. How this feat is achieved time and time again remains a mystery and is of intense interest to the biological and medical communities. One of the central aspects of this feat is the rapid shifts in molecular programs during developmental transitions. These shifts must occur at multiple levels including the regulation of transcription, mRNA stability, protein translation, protein stability, and protein activity. Regulation occurs with the help of transcription factors (activators and suppressors), epigenetic enzymes, non-coding RNAs, RNA binding proteins, ubiquinating enzymes, kinases, phosphatases, and more. Of great interest are a specific group of non-coding RNAs, the microRNAs, which are only 18–24 nucleotides in length and function by both destabilizing and inhibiting translation of mRNAs. microRNAs are compelling regulators of developmental progression as their promiscuous nature allows a single miRNA to regulate hundreds of mRNAs, simultaneously allowing rapid shifts in the transcriptome and proteome of cells.