Fig. 7

BRE::gfp transcriptionally active ECs are rarely proliferative. Transverse sections of E12.5 (a, c) and E14.5 (b, d) BRE::gfp mouse embryos with immunodetection of the proliferation marker (pH3), GFP and Endomucin (a–b) or PROX1 (c–d). Dorsal skin biopsies obtained from E14.5 (e, g) and E16.5 (f, h) BRE::gfp embryos show pH3, GFP and Endomucin (e–f) or PROX1 (g–h) staining. Boxed areas are enlarged in the right panels. i Overview of an E11.5 heart with immunodetection of GFP and pH3. DAPI is used to stain nuclei. The sprouting front (left panels) and centre (right panels) of P3 (j) and P8 (k) retinas with immunodetection of GFP, Endomucin and pH3. Arrows point to pH3-positive ECs. AVC: atrioventricular canal; IVS: inter-ventricular septum; LA: left atrium; LV; left ventricle; RA: right atrium; RV: right ventricle. Scale bars: 100 μm (i); 75 μm (e–h, left panels; j–k); 50 μm; 25 μm (right panels)