Fig. 6

Tie2-cre Hhex^fl/fl mouse embryos exhibit minor vascular defects and a reduced number of PROX1⁺ endothelial cells at E10.5. a Whole-mount view of Hhex^fl/fl and Tie2-cre Hhex^fl/fl embryos at E10.5. Hhex mutants exhibit pericardial edema (red arrowhead) as well as developmental delay. b, c Whole-mount views of Hhex^fl/fl and Tie2-cre Hhex^fl/fl embryos at E10.5 after FLT4 immunostaining. Hhex mutants exhibit a strong decrease in FLT4 expression in the intersomitic vessels (arrowheads point to intersomitic vessels; asterisks indicate reduction of FLT4 expression in the same structures). d–f Whole-mount view of Hhex^fl/fl and Tie2-cre Hhex^fl/fl embryos at E10.5 after PECAM immunostaining. Hhex mutants exhibit minor vascular defects in the head (arrowheads point to blood vessels in Hhex^fl/fl and Tie2-cre Hhex^fl/fl; asterisk indicates lack of vessels in the same structures in Tie2-cre Hhex^fl/fl). g, h Maximum intensity projections of confocal images from transverse cryosections of Hhex^fl/fl and Tie2-cre Hhex^fl/fl E10.5 embryos after immunostaining for PECAM (white) and PROX1 (green) in the cardinal vein (CV) and aorta (A) region. Hhex mutants exhibit fewer PROX1⁺/PECAM⁺ endothelial cells in the region of the CV (arrowheads point to PROX1⁺/PECAM⁺ endothelial cells). i Quantification of the number of PROX1⁺ endothelial cells in the CV region in Hhex^fl/fl (n = 2) and Tie2-cre Hhex^fl/fl (n = 2) embryos. Values represent means ± s.e.m. **P ≤ 0.01 by t-test. Scale bars: 1 mm (a, d), 200 μm (b, c), 500 μm (e, f), and 20 μm (g, h)