Figure 7.

Histological comparison and assessment of gene expression in E14.5 Nkx2.5^+/+; Hand1^SF-A126FS/+ control and Nkx2.5^Cre/+; Hand1A^126FS/+mutants. (A) H&E transverse Control hearts show a patent IVS and separate RV and LV with a well-established compact zone (black bar), RA, and LA. (B) Nkx2.5^Cre/+; Hand1^A126FS/+mutants consistently display VSDs (asterisk) and thin poorly developed compact zone (black bar). LV chamber size is unaffected. (C–F) E14.5 Bmp10 expression reveals a loss trabecular expression. Black boxes in (C, D) define the higher magnification images of (E) and (F). Lines through compact zone measures thickness. (G–J) Dkk3 expression is upregulated in E14.5 Nkx2.5^Cre/+; Hand1^A126FS/+mutants. Boxes in (G) and (H) define the higher magnification view shown in (I) and (J). Data represent an example of each genotype. Six embryos per genotype were examined. ra, right atria; la, left atria; rv, right ventricle; lv, left ventricle; ivs, intraventricular septum. Scale bars 500 and 100 μm.