Roles of COUP-TFII in retinal vascular development. Analysis of changes in retinal microvasculature by Isolectin B4 staining of retinal vessels from P8 mice. Animals were treated with tamoxifen at E18.5 to induce COUP-TFII deletion at the postnatal stage. Relative Isolectin B4-positive density and number of vessel branch points are graphed as mean (±SEM) (N = 10) * P < 0.05. We showed that the complexity and density of the vascular network were substantially reduced in the mutant retina in comparison with the control retina. F/F: COUP-TFIIFlox/Flox; Cre/+, F/F: Rosa26CreERT2/+, COUP-TFIIFlox/Flox.