Fig. 4.

The SOXF/RBPJ-dependent Dll4-12 enhancer is specifically active in SV-derived coronary arteries. a Schematic of the Dll4-12 enhancer:lacZ transgene, with verified binding motifs for ETS, RBPJ and SOXF transcription factors represented by coloured shapes¹⁹. b Whole-mount images and transverse sections of Dll4-12:lacZ transgenic hearts demonstrate selective enhancer activity (blue staining) in coronary arterial endothelium. All images are from a single transgenic line and are representative of at least five biologically independent samples, little variation in staining pattern was seen. Supplemental Figure 11 shows comparative expression patterns in a second Dll4-12:lacZ stable transgenic mouse line. c, d Transverse sections through Dll4-12:lacZ E15.5 (c) and P0 (d) hearts show Dll4-12 enhancer activity (blue) compared to pan-endothelial marker CD31 (green in top panel, yellow in lower panel), the arterial markers α-SMA (red) and DLL4 (green) and the venous/endocardial marker EMCN (yellow). Representative of eight (c) and five (d) biologically independent immunohistological experiments, with similar staining patterns seen in all. Grey boxed regions are shown in Supplementary Figs. 11c and 12a. Black/white arrows indicate the endocardium, red arrowheads indicate arteries and blue arrowheads indicate veins. ra, right atrium; la, left atrium; rv, right ventricle; lv, left ventricle. Black scale bars represent 500 μm