Tead4 is constitutively nuclear, while nuclear vs. cytoplasmic Yap distribution is regulated in preimplantation mouse embryos

Home et al. (1) propose a provocative model of cell fate specification in preimplantation embryos, in which regulated nuclear localization of Tead4 controls trophectoderm vs. inner cell mass (ICM) formation, whereas its coactivator protein, Yap, is present in all nuclei. This model is inconsistent with our model in which position-dependent Hippo/Lats signaling regulates nuclear versus cytoplasmic Yap distribution whereas Tead4 is constitutively nuclear (2). Our model is consistent with the canonical Hippo signaling pathways conserved from flies to mammals (3). Because both models are highly dependent on the antibodies used for Tead4 and Yap, we repeated the immunostaining experiments involving preimplantation embryos with the antibodies used by Home et al. (1).