Movie 3

β-catenin null embryonic hearts display reduced right ventricular size and increased percentage of NkxECs. Embryonic hearts from heterozygous (left) and homozygous (right) β-catenin null mutants were serially sectioned and imaged by confocal microscopy. Nuclei (blue), VEGFR2^GFP+ ECs (green) and Nkx2.5^Cre:tdTomato⁺ cells (red) are shown.