Semiconserved regulation of mesendoderm differentiation by microRNAs.

MicroRNAs are known to play important roles in many different processes. However, their roles in shaping the early steps in embryogenesis have remained largely hidden. In this issue of Developmental Cell, Rosa et al. show that the miR-430/427/302 family of microRNAs has a distinct effect on Nodal signaling, affecting mesendoderm differentiation in Xenopus embryos and human embryonic cell lines.