Additional Supporting Information may be found in the online version of this article.

DVDY_23833_sm_SuppFig1.pdf12549KSupp. Fig. S1. Interactive pdf files of 3D-reconstructions in WT embryos stage E11.5 (a), stage E12.5 (b), and E14.5 (c) that can be used to optimise insight of the orientation of the Nkx2.5-positive column of cells in relation to other cardiac structures. For viewing these files, Adobe reader version 8.0 or higher is required. To use the interactive file, one should open the pdf file, and expand the cardiac compartments by clicking on the small “plus” sign in the top left panel, just left of the text “Heart E11.5,” “Heart E12.5,” or “Heart E14.5,” for Supp. Figures S2a–c, respectively. In some versions, the so-called “Toggle Model Tree,” that can be found in the superior toolbar (just above the 3D figure) needs to be clicked before the top and bottom left panels appear. The default setting of the 3D-image in the right panel is an anterior view of the heart, with all the cardiac compartments depicted. Colour coding is as follows: Grey: myocardium; dark blue: ductus arteriosus/pulmonary trunk/pulmonary arteries; red: aorta; yellow: Nkx2.5-expressing mesenchymal cells; light blue: endocardial cushion tissue. These different cardiac compartments and colour codes are also shown in the left side of the pdf, after clicking the expansion (“plus”) icon described above. By clicking on the marks (v's), one can choose to eliminate different compartments from the figure. Also, by right clicking on the text describing the different compartments, one can choose for the option “transparent” in order to make the compartment of choice transparent to visualize the Nkx2.5-positive column of cells more clearly. In the bottom left panel, other views are depicted that will appear when clicking on them. These other views include a left lateral view, right lateral view, dorsal view, and a superior view. One can also manually choose the preferred view by moving the mouse over the 3D-animation.
DVDY_23833_sm_SuppMovie1.avi33625KSupp. Movie S1. Animated 3D-reconstruction demonstrating the column of Nkx2.5-expressing cells (bright yellow) within the heart and anterior heart field at ED 12.5. This column is rendered transparent during part of the animation to demonstrate its relation to the aorta (red) and pulmonary trunk (dark blue). The outflow tract and right ventricle are depicted in light-yellow, whereas the left ventricle is depicted in grey. Light blue, endocardial cushion tissue

Please note: Wiley Blackwell is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.