Endocardial-derived MCs have migrated into ventricular free walls and septum at E16. 5.
A, whole-mount fluorescence views of the hearts with the indicated genotypes, which were administered with tamoxifen at E9.5 and harvested at E16.5. Scale bars, 2 mm. B, immunostaining for tdTomato on heart sections (sections 1–20, from dorsal to ventral) from Nfatc1–Dre;Sox9–CreER;Ai66 at E16.5. DAPI, 4′,6′-diamino-2-phenylindole. Scale bars, 500 μm. Three individual mouse samples have been examined for each experiment.