Brain or Brawn How FGF Signaling Gives Us Both

How does FGF (fibroblast growth factor) signaling induce both neural and mesodermal cell fates in the early embryo? Two papers address this fundamental question in this issue of Cell. Bertrand et al. show in the ascidian that a GATA factor determines the neural response of animal cells to FGF signaling, while in the chick, Sheng et al. demonstrate that the slow induction by FGF of a new transcription factor (Churchill) in the neural plate in turn induces expression of Sip1 (Smad interacting protein-1), which inhibits mesodermal genes and sensitizes cells to later neural inducing factors.