Fig. 6. Abnormal vasculature in the runx1-mo embryos demonstrated by molecular (A,B,E,F,I,J) and histological (C,D,G,H,K,L) analyses at 48 hpf. Expression of hbbe3 (globin) (A,B) and flk-1 (E,F,I,J). Lateral views of whole embryos (A,B) and posterior embryo region (E,F,I,J); anterior towards the left. Cross sections of the mid-trunk (C,D) and tail (G,H,K,L) regions. (K,L) Higher magnifications of G,H, respectively. Controls are indicated. (A) hbbe3 (globin) expression is limited to the posterior embryo (arrow) with lack of expression in the circulation (arrowhead). (B) Normal hbbe3 (globin) expression within vitelline vessels (arrowhead) and aorta (arrow). (E) ‘Wavy’ pattern of flk-1 expression in axial vessels (arrowhead). (F) Ectopic (arrowhead) and missing (arrow) flk-1 expression. (I) Interrupted expression in the axial vein (arrow), expansion of expression in the tail (black arrowhead) and a loss of expression in intersegmental vessels (blue arrowhead). (J) Normal flk-1 expression in the axial vessels (arrow) and intersegmental vessels (blue arrowhead). (C) Multiple and disorganized vascular channels replacing normal trunk vessels (arrow). (D) Normal dorsal aorta (arrow) and axial vein (arrowhead). (G,K) Expansion of tail region with multiple dilated capillaries (arrow). (H,L) Normal caudal vessels (arrows). Scale bars: 50 µm.