MicroRNA-mediated control in the skin.

Skin, the biggest organ in mammals, protects the body from environmental hazards and prevents dehydration. Embryonic skin morphogenesis and homeostasis of adult skin require an accurately controlled gene expression in a spatiotemporally specific manner. Recently, the identification of microRNAs (miRNAs) in skin has added a new dimension in the regulatory network and attracted significant interest in this novel layer of gene regulation. Mammalian skin with its easy accessibility, well-defined lineages and established genetic tools offers an ideal system to unravel the functions of miRNAs in mammalian development and stem cells. In the past few years, significant progress has been made in determining the expression patterns of miRNAs, exploring their functions in skin morphogenesis and differentiation, as well as probing their functions in human skin diseases, for example, skin cancer. In this review, we summarized current progress in the study of miRNA in mammalian skin, provided insights gained from recent studies and offered our views for remaining challenges.