Antibody:	anti-alpha-SMA (IMMH2)
Detection system:	Secondary antibody coupled to horseradish peroxidase
Assay notes:	Fixative was: 40% methanol: 40% acetone: 20% water.

Structure	Level	Pattern	Image	Note
TS15: outflow tract	Present	Regionally restricted	2d , 2f , 2b	Expression is in the myocardium.
TS15: embryo mesoderm	Present	Regionally restricted	2d , 2f , 2b	Expression is in the mesodermal cells adjacent to the outflow tract.

Structure	Level	Pattern	Image	Note
TS19: aortico-pulmonary spiral septum	Present		3b
TS19: endocardial cushion	Absent		3b
TS19: embryo mesoderm	Absent		3b	Expression is absent in the mesodermal cells flanking the outflow tract myocardium.

Structure	Level	Pattern	Image	Note
TS20: endocardial cushion	Present	Regionally restricted	3d	Expression is in a subpopulation of mesenchymal cells.

Structure	Level	Pattern	Image	Note
TS21: heart septum	Present	Regionally restricted	3f	Expression is in mesenchymal cells in a large part of the outlet septum.

Structure	Level	Pattern	Image	Note
TS23: heart septum	Strong	Regionally restricted	3h	Expression is in cardiomyocytes extending into the adjacent mesenchyme.

Structure	Level	Pattern	Image	Note
TS17: sinus venosus left horn	Present		4b
TS17: sinus venosus right horn	Present		4b

Structure	Level	Pattern	Image	Note
TS19: sinus venosus	Present		4d
TS19: cardinal vein	Present	Regionally restricted	4d	Expression is in nonmyocardinal cells along the cardinal veins.

Structure	Level	Pattern	Image	Note
TS21: left superior vena cava	Present	Regionally restricted	4f	Expression is in the wall.
TS21: right superior vena cava	Present	Regionally restricted	4f	Expression is in the wall.

Structure	Level	Pattern	Image	Note
TS20: dorsal mesocardium	Strong		5b

Structure	Level	Pattern	Image	Note
TS19: dorsal mesocardium	Present		5d
TS19: heart	Present	Regionally restricted	5d	Expression is in the spina vestibuli mesenchyme.

Structure	Level	Pattern	Image	Note
TS21: septum primum	Present	Regionally restricted	6b	Expression is at the caudal tip.

Structure	Level	Pattern	Image	Note
TS21: interventricular septum muscular part	Present	Regionally restricted	6d	Expression is at the cranial tip.
TS21: atrioventricular endocardial cushion	Present	Regionally restricted	6d	Expression is in the mesenchyme.
TS21: heart	Present	Regionally restricted	6d	Expression is in the mesenchyme adjacent to the atrioventricular cushion mesenchyme.

Structure	Level	Pattern	Image	Note
TS22: interventricular septum muscular part	Strong	Regionally restricted	6f	Expression is at the cranial tip.
TS22: cardiac muscle tissue	Strong		6f

Structure	Level	Pattern	Image	Note
TS22: interventricular septum muscular part	Strong	Regionally restricted	6h	Expression is at the cranial tip.
TS22: cardiac muscle tissue	Strong		6h
TS22: septum primum	Present	Regionally restricted	6h	Expression is at the caudal tip.

Structure	Level	Pattern	Image	Note
TS17: heart	Strong	Regionally restricted	7b	Expression is in the pulmonary pit.

Structure	Level	Pattern	Image	Note
TS19: dorsal mesocardium	Present	Regionally restricted	7d	Expression is in the pulmonary vein.
TS19: vein	Present	Regionally restricted	7d	Expression is in the pulmonary vein.

Structure	Level	Pattern	Image	Note
TS21: dorsal mesocardium	Present	Regionally restricted	7f	Expression is in the pulmonary vein.
TS21: vein	Present	Regionally restricted	7f	Expression is in the pulmonary vein.

Structure	Level	Pattern	Image	Note
TS22: vein	Strong	Regionally restricted	7h	Expression is in the pulmonary vein at the level of the first bifurcation.