Probe:	activin betaA cDNA1
Probe preparation:	Antisense labelled with digoxigenin RNA
Visualized with:	Alkaline phosphatase
Assay notes:	Antisense probes to the 5' (in this assay) and 3' ends (MGI:1276505) resulted in similar patterns. It was not stated which probe was used in the assay. Either probe may have been used.

Structure	Level	Pattern	Image	Note
TS17: heart septum	Present	Regionally restricted	2A left	Strongest expression was in the interventricular septum.
TS17: atrioventricular canal	Present		2A left	Strongest expression.
TS17: heart atrium	Weak		2A left
TS17: primitive ventricle	Weak		2A left
TS17: outflow tract	Present		2A left	Slightly darker staining.

Structure	Level	Pattern	Image	Note
TS17: heart septum	Present	Regionally restricted	2B left	Strongest expression was in the interventricular septum.
TS17: atrioventricular canal	Present		2B left	Strongest expression.
TS17: heart atrium	Weak		2B left
TS17: primitive ventricle	Weak		2B left
TS17: outflow tract	Present		2B left	Slightly darker staining.

Structure	Level	Pattern	Image	Note
TS18: atrioventricular canal	Present		2C left	Expression was much more intense.
TS18: heart septum	Present		2C left	Expression was much more intense.
TS18: interatrial septum	Present		2C left	Expression was much more intense.

Structure	Level	Pattern	Image	Note
TS17: heart septum	Present	Regionally restricted	2D	Expression is prominent on the surface of the interventricular septum.
TS17: atrioventricular endocardial cushion	Present	Regionally restricted	2D	Expressed in the dorsal.
TS17: cardiac muscle tissue	Weak		2D

Structure	Level	Pattern	Image	Note
TS18: atrioventricular endocardial cushion	Strong		3A , 3B	Most abundant expression in mesenchymal cells.
TS18: heart septum	Present	Regionally restricted	3B , 3A	Expression is most abundant in cells on the surface of the interventricular septum.
TS18: atrium cardiac muscle	Present	Regionally restricted	3A	Expressed in one region.
TS18: heart mesenchyme	Present	Regionally restricted	3A , 3B	Expressed within the rest of the interventricular septum.
TS18: cardiac muscle tissue	Present	Regionally restricted	3B , 3A	Expressed in myocardium adjacent to mesenchymal cells in the atrioventricular region.