(A) Maximum intensity projection of different organ stained with Pimonidazole (green) and DAPI (blue) at P21. (B) Representative confocal images of the vasculature in different organs from 3-week-old Cdh5-mTnG reporter mice (red, mTom; green, H2B-GFP; blue, DAPI). Panels on the left show maximum intensity projections, single focal planes are shown on the right. (C) Quantification of average vessel diameter in different organs (μM). (D, E) Tile scan maximum intensity projections of 3-week-old Cdh5-mTnG femur (red, mTom; green, HIF-1α or HIF-2α, as indicated) (D). Nuclear HIF2α immunosignal (red) is prominent in bone marrow (green, H2B-GFP; blue, mTom) (E). (F, G) Tile scan confocal images of 3-week-old Cdh5-mTnG reporter femur and DAPI (blue). The Cdh5-mTnG reporter labels bmECs and mpECs (F). Higher magnification images show H2B-GFP in endothelial nuclei (G).