Tail Bud Progenitor Activity Relies on a Network Comprising Gdf11, Lin28, and Hox13 Genes

Summary During the trunk-to-tail transition, axial progenitors relocate from the epiblast to the tail bud. Here, we show that this process entails a major regulatory switch, bringing tail bud progenitors under Gdf11 signaling control. Gdf11 mutant embryos have an increased number of such progenitors that favor neural differentiation routes, resulting in a dramatic expansion of the neural tube. Moreover, inhibition of Gdf11 signaling recovers the proliferation ability of these progenitors when cultured in vitro . Tail bud progenitor growth is independent of Oct4 , relying instead on Lin28 activity. Gdf11 signaling eventually activates Hox genes of paralog group 13, which halt expansion of these progenitors, at least in part, by down-regulating Lin28 genes. Our results uncover a genetic network involving Gdf11 , Lin28 , and Hox13 genes controlling axial progenitor activity in the tail bud.