Fig. 2

HLX-3 enhancer activity is maintained in the coronary vasculature of the post-natal heart. a Whole-mount P0, P8 and adult HLX-3:lacZ transgenic hearts demonstrate enhancer activity in the post-natal heart as detected by blue X-gal staining. 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 apart from in adult heart, an example of the weaker staining intensity is shown in Supplementary Fig. 6b. b Transverse sections sequentially from base to apex through a P0 HLX-3:lacZ heart. HLX-3 enhancer activity is detected by blue staining in coronary vessels located in the intramyocardium and inter-ventricular septum. Enhancer activity (blue) is compared to pan-endothelial marker CD31 (green), the arterial marker α-SMA (red) and the venous/endocardial marker EMCN (yellow). Grey boxed regions are shown in Supplementary Fig. 6a. Representative of three biologically independent immunohistological experiments, with similar staining patterns seen in all. c, d Transverse sections through a P8 (c) and adult (d) HLX-3:lacZ transgenic hearts. Continued HLX-3:lacZ activity (blue) is seen in small vessels of the inner myocardium and inter-ventricular septum. Representative of over five biologically independent samples, examples of lower intensity staining seen in less than half adult hearts is shown in Supplementary Fig. 6b. Black/white arrows indicate the endocardium, red arrowheads indicate arteries and blue arrowheads indicate veins. rv, right ventricle; lv, left ventricle. Black scale bars represent 500 μm