Practice question

Eomesodermin, also called Tbr2, is T-box transcription factor activated downstream of Nodal and Wnt signaling at onset of gastrulation. It cooperates with Brachyury and Mixl1 to specify and maintain nascent mesoderm, particularly cardiac and definitive endoderm lineages, by regulating genes controlling epithelial-to-mesenchymal transition and ingression through primitive streak. Loss of Eomes leads to failure of mesoderm delamination and embryonic lethality. It does not directly mediate zygotic genome activation, germ cell specification or zona digestion, but provides mesodermal competence to epiblast cells ingressing during mammalian gastrulation.