Fig. 3. Endocardial cell patterning defects and abnormal cardiac morphogenesis in the absence of β1 integrins. Endothelial staining of Tie2-Cre (B,D,H) and Tie1-Cre (J) mutants as compared with controls (A,C,G,I). (A-D) Whole-mount anti-CD31 immunostained control (A,C) and Tie2-Cre mutant (B,D) embryos at e9.0 (A,B) and e9.5 (C,D). (E) Diagram of an e9.5 mouse embryo. The dashed line indicates the approximate plane of the cross-section shown in F, and of the e9.5 control (G) and Tie2-Cre mutant (H) cryosections stained with anti-CD31 antibodies. The dashed box in F indicates the approximate location of the e10.5 control (I) and Tie1-Cre mutant (J) paraffin sections stained with anti-VE-cadherin antibodies and DAPI. In F, the endocardium (green) is separated from the myocardium (red) by the cardiac jelly (cj). Arrows, endocardium; arrowheads, intersomitic vessels; da, dorsal aorta; h, heart; a, atrium; v, ventricle; m, myocardium; fg, foregut; hg, hindgut. All images are representative of at least four control/mutant embryo pairs. Scale bars: 100 µm in A-D,G,H; 20 µm in I,J.