Figure 1. VEGF Expression by Endothelial Cells and Generation of VEGF^ECKO Mice.

(A) Expression of LacZ reporter (blue) driven by the VEGF promoter in non-pathological adult tissues. Note promoter activity in endothelial cells (arrows). In larger vessels: positive (arrows) and negative (arrowhead) endothelial cells are observed.

(B) Schematic diagram of the transgenic mice used to generate VEGF^ECKO mice (top). Genotyping of tail DNA. A band of 850 indicates the presence of the Cre transgene. Only animals from lanes 2 and 4 harbored the Cre-recombinase transgene (bottom, left). A 100-bp band indicates wild type (wt) allele and the 150-bp corresponds to the floxed VEGF allele (flox) (bottom, right).

(C) Endothelial cells isolated from Cre+/Rosa+/VEGF^lox/lox (VEGF^ECKO) and Cre-/Rosa+/VEGF^lox/lox mice stained for β-gal. Arrows point to endothelial cells expressing Cre and arrowheads to cells with no Cre expression (approximately 95% of the isolated cells were positive).

(D) Survival analysis. Mortality rate of newborn VEGF^ECKO at P0 was calculated by predicted mendelian distribution and expected litter size. Survival rate of VEGF^ECKO at six months was 34.7%.

(E) Mortality of adult cohorts.

(F) Litter size variability. Wt × Wt, 6 ± 1.33 (n = 10); Wt/KO × Wt/KO, 7.15 ± 1.76 (n = 20); KO/KO, 4.0 ± 1.30 (n = 11).