ORIGINAL ARTICLE Snail and the microRNA-200 Family Act in Opposition to Regulate Epithelial-to-Mesenchymal Transition and Germ Layer Fate Restriction in Differentiating ESCs

The reprogramming of somatic cells to inducible pluripo-tent stem cells requires a mesenchymal-to-epithelial transi-tion. While differentiating ESCs can undergo the reverse process or epithelial-to-mesenchymal transition (EMT), lit-tle is known about the role of EMT in ESC differentiation and fate commitment. Here, we show that Snail homolog 1 (Snail) is expressed during ESC differentiation and is ca-pable of inducing EMT on day 2 of ESC differentiation. Induction of EMT by Snail promotes mesoderm commit-ment while repressing markers of the primitive ectoderm and epiblast. Snail’s impact on differentiation can be partly explained through its regulation of a number of ESC-associated microRNAs, including the microRNA-200 (miR-200) family. The miR-200 family is normall