Antibody:	anti-type VI collagen
Detection system:	Secondary antibody coupled to fluorescein
Assay notes:	Specimens were fixed using a modified cryofixation method that produces rapidly frozen, freeze-substituted tissues using liquid nitrogen overlaying frozen 100% ethanol and a layer of molecular sieve dehydrating beads. The antibody used recognizes Col6a1-3 and all have been annotated.

Structure	Level	Pattern	Image	Note
TS15: atrioventricular endocardial cushion	Strong	Regionally restricted	3A/B	Expression is at the basal surface of transformed mesenchymal cells.

Structure	Level	Pattern	Image	Note
TS17: cardiac jelly	Present		3C/D

Structure	Level	Pattern	Image	Note
TS21: endocardial cushion	Present		3E/F
TS21: cardiac muscle tissue	Weak	Regionally restricted	3E/F	Expression is in the myocardial interstitium.

Structure	Level	Pattern	Image	Note
TS24: atrioventricular valve	Strong	Regionally restricted	4F	Expression is reduced in the proximal atrial aspect of the atrioventricular valve leaflet compared with a clear signal in the ventricular side.
TS24: cardiac valve leaflet	Strong	Regionally restricted	4F	Expression is reduced in the proximal atrial aspect of the atrioventricular valve leaflet compared with a clear signal in the ventricular side.

Structure	Level	Pattern	Image	Note
TS22: atrioventricular valve	Present		5A

Structure	Level	Pattern	Image	Note
TS23: atrioventricular valve	Present		5B	Expression stronger on the ventricular side.
TS23: cardiac valve leaflet	Present		5B	Expression stronger on the ventricular side.