The figure depicts the lateral view of the anterior portion of an e8.25 (2–4 somite stage) mouse embryo (right). The developing head is shown in grey. At this stage the definitive endoderm (yellow) is forming a foregut pocket. The liver (lv) is induced a portion of the ventral foregut by FGF signals from the cardiogenic mesoderm (red) and BMPs from the septum transversum mesenchyme (orange). Foregut endoderm isolated after the 5–7 somite stage will express liver genes such as Albumin, indicating that hepatic fate is specified. Different doses of FGF appear to induce lung (lu) and ventral pancreas (pa) from the foregut progenitors. Signals from the axial mesoderm (candidates included FGF4 and Wnt ligands) repress hepatic fate in the dorsal endoderm.
From: Liver development
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