Antibody:	Anti-Scn1b
Detection system:	Secondary antibody coupled to Cy3

Structure	Level	Pattern	Image	Note
TS15: atrioventricular canal	Present		3B	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.
TS15: common atrial chamber cardiac muscle	Present		3B	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.
TS15: outflow tract	Present		3B	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.
TS15: primitive ventricle cardiac muscle	Present		3B	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.

Structure	Level	Pattern	Image	Note
TS15: atrioventricular canal	Present		3D	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.
TS15: common atrial chamber cardiac muscle	Present		3D	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.
TS15: outflow tract	Present		3D	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.
TS15: primitive ventricle cardiac muscle	Present		3D	Expression was similar in all cardiac compartments, i.e. atrial and ventricular myocardium, and atrioventricular canal and outflow tract.

Structure	Level	Pattern	Image	Note
TS17: cardiac muscle tissue	Present	Non-Uniform	3F	Staining remains in all compartments but is higher in ventricular trabeculated myocardium and the prospective right and left bundle branches on either side of the ventricular septum as compared with the nascent interventricular septum.
TS17: heart	Present	Non-Uniform	3F	Staining remains in all compartments but is higher in ventricular trabeculated myocardium and the prospective right and left bundle branches on either side of the ventricular septum as compared with the nascent interventricular septum.
TS17: primitive ventricle	Present	Non-Uniform	3F	Staining remains in all compartments but is higher in ventricular trabeculated myocardium and the prospective right and left bundle branches on either side of the ventricular septum as compared with the nascent interventricular septum.

Structure	Level	Pattern	Image	Note
TS19: heart	Present	Non-Uniform	3G	Staining remains in all compartments but is higher in ventricular trabeculated myocardium and the prospective right and left bundle branches on either side of the ventricular septum as compared with the nascent interventricular septum.
TS19: interventricular septum	Weak		3G
TS19: ventricle cardiac muscle	Strong		3G

Structure	Level	Pattern	Image	Note
TS20: interventricular septum	Weak		3H
TS20: left ventricle cardiac muscle	Strong	Regionally restricted	3H	Strong in ventriculat trabeculations and in prospective right and left bundle branches.
TS20: right ventricle cardiac muscle	Strong	Regionally restricted	3H	Strong in ventriculat trabeculations and in prospective right and left bundle branches.

Structure	Level	Pattern	Image	Note
TS21: left ventricle cardiac muscle	Strong	Non-Uniform	3L , 3I , 3M , 3J , 3K	High in right and left bundle branches and trabeculated ventricular myocardium as compared to ventricular compact myocardium.
TS21: right ventricle cardiac muscle	Strong	Non-Uniform	3L , 3I , 3M , 3J , 3K	High in right and left bundle branches and trabeculated ventricular myocardium as compared to ventricular compact myocardium.
TS21: interventricular septum	Weak		3J , 3M , 3I , 3K , 3L

Structure	Level	Pattern	Image	Note
TS25: heart ventricle	Strong	Regionally restricted	4A	Strong expression was detected in trabecular ventricular components.

Structure	Level	Pattern	Image	Note
TS25: ventricle cardiac muscle	Strong	Regionally restricted	4B	Strong expression was detected in trabecular ventricular myocardium

Structure	Level	Pattern	Image	Note
TS25: heart	Strong	Non-Uniform	4F , 4E	Strong expression in the peripheral sinoatrial node and weak in the central SA node.

Structure	Level	Pattern	Image	Note
TS25: cardiac muscle tissue	Present	Non-Uniform	4H	Weak expression in the Bundle of His but stronger expression in the left bundle branches.

Structure	Level	Pattern	Image	Note
TS27: left atrium	Present		4J	Exprssion in the right and left Atrial appendages.
TS27: right atrium	Present		4J	Exprssion in the right and left Atrial appendages.

Structure	Level	Pattern	Image	Note
TS27: heart left ventricle	Present	Regionally restricted	4K	Expression detected in the compact wall of the right and left ventricle.
TS27: heart right ventricle	Present	Regionally restricted	4K	Expression detected in the compact wall of the right and left ventricle.

Structure	Level	Pattern	Image	Note
TS27: heart	Present	Regionally restricted	4L	Expression detected in the interventricular septum and the right bundle branch.

Structure	Level	Pattern	Image	Note
TS27: heart left ventricle	Present	Regionally restricted	4M	Expression detected in the compact wall of the right and left ventricle.
TS27: heart right ventricle	Present	Regionally restricted	4M	Expression detected in the compact wall of the right and left ventricle.

Structure	Level	Pattern	Image	Note
TS27: left atrium	Present		4N	Exprssion in the right and left Atrial appendages.
TS27: right atrium	Present		4N	Exprssion in the right and left Atrial appendages.

Structure	Level	Pattern	Image	Note
TS20: heart	Present	Regionally restricted	5A	Punctate labelling observed in the cytoplasm and cell surface.

Structure	Level	Pattern	Image	Note
TS20: heart	Present	Regionally restricted	5B	Punctate labelling observed in the cytoplasm and cell surface.

Structure	Level	Pattern	Image	Note
TS25: heart	Present	Regionally restricted	5C	Expression detcted in the cardiac fibers in the T-tubular system and the intercalated disks.

Structure	Level	Pattern	Image	Note
TS27: heart	Present	Regionally restricted	5E	Expression detected in the surface of cardiac muscle cells and intercalated disks.

Structure	Level	Pattern	Image	Note
TS28: heart	Present	Regionally restricted	5G	Expression detected in the surface of cardiac muscle cells and intercalated disks.