Fig. 4. Cited2-null embryos show a range of pulmonary and cardiac defects. Two dimension EFIC sections at 14.5 dpc through corresponding planes of a Cited2-null embryo (A-C) and a wild type (D-F) embryo. Cited2-null embryos show symmetrical arrangement of lung lobes, similar symmetry is evident in the size, topology and branching of the left and right principal bronchus (PB) and lobar bronchi (LB). Cited2-null embryos show cardiac defects that include a ventricular septal defect (arrows in A and B) and symmetrical right and left atrial appendages (aa) adjoining a median chamber (asterisk in B). Histological sections of 14.5 dpc Cited2-null embryos (G,H) show subtypes of atrioventricular junction (J) malformations: (G) single atrioventricular ostium opening solely into the right ventricle, (H) single atrioventricular ostium opening equally into both ventricles because of the large ventricular septal defect. The median atrial chamber is indicated by an asterisk. (I) Retro-esophageal right subclavian artery (arrowhead). E, esophagus; T, trachea; DA, descending aorta; VS, ventricular septum; R, right; L, left. Scale bar: 500 µm in A-F; 500 µm in G-I.