Antibody:	Anti-Podoplanin (clone 8.1.1)
Detection system:	Biotinylated secondary antibody/[Strept]avidin coupled to horseradish peroxidase

Structure	Level	Pattern	Image	Note
TS19: heart	Present	Non-Uniform	1i , 1k , 1j	Expression is stronger at the left side especially in the premyocardial mesenchyme running from the left pericardio-peritoneal canal, caudal of the anlage of the conrmon pulmonary vein through the base of the atrial septum to the posterior part of the atrioventricular canal dorsal of the inferiror atrioventricular cushion.
TS19: atrioventricular canal	Present	Regionally restricted	1i , 1k , 1j	Expression is in the premyocardial mesenchyme in the posterior part.
TS19: heart mesenchyme	Present	Regionally restricted	1k , 1j , 1i	Expression is in the premyocardial mesenchyme running from the left pericardio-peritoneal canal, caudal of the anlage of the common pulmonary vein through the base of the atrial septum to the posterior part of the atrioventricular canal dorsal of the inferiror atrioventricular cushion.
TS19: interatrial septum	Present	Regionally restricted	1j , 1i , 1k	Expression is in the premyocardial mesenchyme.
TS19: cardiac muscle tissue	Present	Regionally restricted	1j , 1i , 1k
TS19: pericardial component	Present	Regionally restricted	1j , 1i , 1k
TS19: trunk mesenchyme	Present	Regionally restricted	1j , 1i , 1k	Expression is in the mesenchyme adjoining the medial wall of the left superior cardinal vein and is weak alongside the right superior vein at the posiiton of the developing right sinoatrial node.

Structure	Level	Pattern	Image	Note
TS21: cardiac muscle tissue	Present	Regionally restricted	2l , 2k	Expression is in the myocardium of the developing rightsided sinoatrial node.
TS21: sinoatrial node	Present	Regionally restricted	2l , 2k	Expression is in the myocardium of the developing rightsided sinoatrial node.
TS21: heart	Present	Regionally restricted	2k , 2l	Expression is in a leftsided cluster between the left cardinal vein partly merging with the pulmonary vein wall and extending into the base of the atrial septum.
TS21: great vessel of heart	Present	Regionally restricted	2k , 2l	Expression is in part of the the pulmonary vein wall.
TS21: interatrial septum	Present	Regionally restricted	2k , 2l
TS21: intraembryonic coelom	Present	Regionally restricted	2k , 2l	Expression is in the lining of the coelomic cavity in areas with underlying positive myocardium.
TS21: pericardial component	Present	Regionally restricted	2k , 2l	Expression is in the lining of the coelomic cavity in areas with underlying positive myocardium.
TS21: right atrium venous valve	Present	Patchy	2l , 2k
TS21: atrium cardiac muscle	Absent		2k , 2l

Structure	Level	Pattern	Image	Note
TS21: heart	Present	Regionally restricted	2n , 2m	Expression is in a leftsided cluster between the left cardinal vein partly merging with the pulmonary vein wall and extending into the base of the atrial septum.
TS21: sinoatrial node	Present	Regionally restricted	2n , 2m	Expression is in the myocardium of the developing right-sided sinoatrial node.
TS21: great vessel of heart	Present	Regionally restricted	2m , 2n	Expression is in part of the the pulmonary vein wall.
TS21: intraembryonic coelom	Present	Regionally restricted	2n , 2m	Expression is in the lining of the coelomic cavity in areas with underlying positive myocardium.
TS21: pericardial component	Present	Regionally restricted	2n , 2m	Expression is in the lining of the coelomic cavity in areas with underlying positive myocardium.
TS21: cardiac muscle tissue	Present	Regionally restricted	2m , 2n
TS21: impulse conducting system	Present	Regionally restricted	2m , 2n	Expression is in the common bundle.

Structure	Level	Pattern	Image	Note
TS21: impulse conducting system	Present	Regionally restricted	3c , 3d	Expression is in the common bundle and in the right and left bundle branches.
TS21: sinoatrial node	Present	Regionally restricted	3c , 3d	Expression is in the common bundle and in the right and left bundle branches.

Structure	Level	Pattern	Image	Note
TS23: impulse conducting system	Present	Regionally restricted	3e , 3f	Expression is in the common bundle and in the right and left bundle branches.
TS23: sinoatrial node	Present	Regionally restricted	3e , 3f	Expression is in the common bundle and in the right and left bundle branches.

Structure	Level	Pattern	Image	Note
TS15: cardinal vein	Weak	Regionally restricted		Expression is weak on the left side and is absent at the right side on the medial border of the cardinal veins wall.