αSMA and EphB4 expression in coronary arteries of CHF1/Hey2 knockout mice rescued with a myocardial CHF1/Hey2 transgene. E18.5 left ventricles of either CHF1/Hey2 knockout mice (n = 4) (a, b), CHF1/Hey2 knockout with CHF1/Hey2 transgene mice (n = 4) (c, d) or wild-type without transgene mice (n=3)(e, f) were immunostained with anti-αSMA antibody (a, c, e) or anti-EphB4 antibody (b, d, f). Coronary arteries (a, c, e) and veins (b, d, f) were indicated by arrows. Scale bars = 200 μm.