Restricted or delayed process of myocardialization observed in the <i>Vcan</i>^(tm1Zim) hearts.

<p>E13.5 pc wild-type hearts (A, B) compared to <i>Vcan</i>^(tm1Zim) (C, D). The image in each panel is one taken from sections through the right parietal cushions at their thickest margin. Panels A and C utilize both periostin staining (green) and α-sarcomeric actin (red) to mark the cushion and muscle boundaries (propidium iodide marks the cell nuclei in blue). Panels B and D are the same image as A and C with periostin and propidium iodide staining removed to show the extent of muscle cells (α-sarcomeric actin positive) present within the cushion more clearly (A & B; arrows mark the muscle boundary; dotted lines mark the boundaries of the cushion). The WT hearts show that muscle cells are present in the cushion. The <i>Vcan</i>^(tm1Zim) hearts show little or no presence of muscle into the adjacent matrix of the phenotypically smaller cushions of the <i>Vcan</i>^(tm1Zim) hearts (B, C). IVS-interventricular septum. Magnification bar in panel A = 100 µm and applies to all panels.