Functional screen reveals essential roles of miR‐27a/24 in differentiation of embryonic stem cells. (17th December 2014) - Ma, Yanni
Abstract: MicroRNAs play important roles in controlling the embryonic stem cell (ESC) state. Although much is known about microRNAs maintaining ESC state, microRNAs that are responsible for promoting ESC differentiation are less reported. Here, by screening 40 microRNAs pre‐selected by their expression patterns and predicted targets in Dgcr8 ‐null ESCs, we identify 14 novel differentiation‐associated microRNAs. Among them, miR‐27a and miR‐24, restrained by c‐Myc in ESC, exert their roles of silencing self‐renewal through directly targeting several important pluripotency‐associated factors, such as Oct4, Foxo1 and Smads. CRISPR/Cas9‐mediated knockout of all miR‐27/24 in ESCs leads to serious deficiency in ESC differentiation in vitro and in vivo . Moreover, depleting of them in mouse embryonic fibroblasts can evidently promote somatic cell reprogramming. Altogether, our findings uncover the essential role of miR‐27 and miR‐24 in ESC differentiation and also demonstrate novel microRNAs responsible for ESC differentiation. Synopsis: A focused screen, followed by CRISPR/Cas9 functional genome editing establishes the miR‐23~27~24 cluster as essential regulator of self‐renewal and ESC‐differentiation. A functional screen annotates 14 miRNAs as new regulators of ESC differentiation. miR‐27a and miR‐24 operate as suppressors of ESC self‐renewal. The inhibition of miR‐27a and miR‐24 promotes somatic cell reprogramming. The miR‐23~27~24 cluster is shown to be essential for mesoderm differentiation. Abstract : A focused screen, followed by CRISPR/Cas9 functional genome editing establishes the miR‐23~27~24 cluster as essential regulator of self‐renewal and ESC‐differentiation.