Smad4 is essential for epiblast scaling and morphogenesis after implantation, but nonessential before implantation.
Kruger RE, Frum T, Brumm AS, Hickey SL, Niakan KK, Aziz F, Shammami MA, Roberts JG, Ralston A. Development. 2024 Jun 1; 151(11). Epub 2024 Jun 5.