Antibody:	MEC 13.3
Detection system:	Secondary antibody coupled to horseradish peroxidase

Structure	Level	Pattern	Image	Note
TS15: endocardial lining	Present	Regionally restricted	3Aa	Immunopositive endothelial cells were detected.
TS15: dorsal aorta	Present	Regionally restricted	3Aa	Immunopositive endothelial cells were detected.

Structure	Level	Pattern	Image	Note
TS15: endocardial lining	Present		3Ab	Immunopositive endothelial cells appeared normal in the heart (in the endocardium) of the mutant.
TS15: dorsal aorta	Present		3Ab	Immunopositive endothelial cells were detected as normal in the dorsal aorta.

Structure	Level	Pattern	Image	Note
TS15: dorsal aorta	Present		3Ac
TS15: endocardial lining	Present		3Ac
TS15: intersomitic blood vessel	Present		3Ac

Structure	Level	Pattern	Image	Note
TS15: endocardial lining	Present		3Ad	Defects were noted in ~30% of mutant hearts. Staining intensity did not appear decreased.
TS15: dorsal aorta	Present		3Ad	Staining intensity did not appear decreased.
TS15: head blood vessel	Present		3Ad	Staining intensity did not appear decreased.
TS15: intersomitic blood vessel	Present		3Ad	Staining intensity did not appear decreased.

Structure	Level	Pattern	Image	Note
TS16: vascular system	Present		3Ae
TS16: head blood vessel	Present		3Ag left , 3Ae

Structure	Level	Pattern	Image	Note
TS16: dorsal aorta	Present		3Af left	Defects were noted in the mutant. Staining intensity did not appear decreased.
TS16: vascular system	Present		3Af left	Defects were noted in the mutant. Staining intensity did not appear decreased.
TS16: head blood vessel	Present		3Af left , 3Ag right	Defects were noted in the mutant. Staining intensity did not appear decreased.

Structure	Level	Pattern	Image	Note
TS16: dorsal aorta	Present		3Af right	Defects were noted in the mutant. Staining intensity did not appear decreased.
TS16: head blood vessel	Present		3Af right	Defects were noted in the mutant. Staining intensity did not appear decreased.
TS16: vascular system	Present		3Af right	Defects were noted in the mutant. Staining intensity did not appear decreased.

Structure	Level	Pattern	Image	Note
TS16: dorsal aorta	Present		3B left
TS16: intersomitic blood vessel	Present		3B left

Structure	Level	Pattern	Image	Note
TS16: dorsal aorta	Present		3B right	Defects were noted in the mutant, as evidenced by discontinuous immunostaining. Staining intensity did not appear decreased.
TS16: intersomitic blood vessel	Present		3B right	Defects were noted in the mutant. Staining intensity did not appear decreased.

Structure	Level	Pattern	Image	Note
TS17: yolk sac blood vessel	Present		3C left

Structure	Level	Pattern	Image	Note
TS17: yolk sac	Present	Regionally restricted	3C right	The mutant lacked organization of vascular endothelial cells at E10.5. Immunostaining showed a sinuous network of endothelial cells that resembled a primitive plexus.