MicroRNAs in pancreas development.

The development of the pancreas is a tightly regulated process involving extensive morphogenesis, proliferation and differentiation of the epithelium. The finely orchestrated control of gene expression plays a key role in this equilibrium by coordinating the expression of selected gene products at specific moments and in precise locations. MicroRNAs (miRNAs) are small non-coding RNAs that function in general as negative regulators of gene transcripts by interacting with the three prime untranslated regions (3'UTR) of target mRNAs. MiRNAs modulate the expression of numerous target genes that are involved in a variety of cellular systems. Hence the homeostatic control of miRNA biosynthesis and activity is important for the fine-tuning of many physiological processes such as cell differentiation, cell proliferation and organ development. In the present review, we will focus on the implication of these miRNAs on the development of the pancreas and more specifically on β-cells.