Fig. 3: Creation of an endothelial-specific Hba1-deletion mouse model.

a Deletion strategy: loxP sites flanking exons 2 and 3 of the mouse Hba1 gene (Hba1^fl/fl) were introduced by recombineering. A tamoxifen-inducible, endothelial-specific Cre recombinase (Cdh5-PAC-Cre^ERT2) enabled temporally controlled and cell-type-specific deletion of a functional Hba1 gene (EC Hba1^Δ/Δ mouse). b DNA gel using genomic DNA extracted from diaphragm showing recombination of the Hba1 locus with Cre activation. The recombination event produced a band at ~450 bp. c, d Immunofluorescence staining for alpha globin in transverse sections of a thoracodorsal artery (top) and en face views of the endothelium of a third-order mesenteric artery (bottom). The scale bar represents 25 μm, and an asterisk indicates lumen of the vessel in the upper images. Alpha globin (red) was found in the endothelium throughout and specifically in the holes in the internal elastic lamina (IEL), where myoendothelial junctions are found. e Control IgG staining showing the specificity of the staining for alpha globin in this tissue. f, g Endothelial deletion of alpha globin does not affect blood cell hemoglobin parameters. Blood hemoglobin content (f), hematocrit (g), and the number of red blood cells (h) were unchanged in the EC Hba1^Δ/Δ mice, as compared to the Hba1^fl/fl controls. For the experiments in f–h, n = 20 Hba1^fl/fl mice and n = 17 EC Hba1^Δ/Δ mice were used; one-sided t tests were used to determine whether there were significant differences between groups. Bar graphs are centered on mean with error bars denoting standard error. Source data are provided in the Source data file.