Antibody:	Anti-smooth muscle alpha-Actin (clone 1A4)
Detection system:	Secondary antibody coupled to fluorescein

Structure	Level	Pattern	Image	Note
TS15: dorsal aorta	Present	Single cells	1a/b	One to three positive cells were localized beneath the endothelium and apart from one another. 12 positive cells per embryo.

Structure	Level	Pattern	Image	Note
TS15: umbilical artery extraembryonic part	Trace	Scattered	1c/d	Very weak and discontinuous staining at the innermost side of the placenta. No staining in the branches within the placenta.
TS15: umbilical vein	Absent		1c/d

Structure	Level	Pattern	Image	Note
TS15: allantois mesenchyme	Present	Regionally restricted	1e/f	Expressed in a momolayer of cells at the innermost side of the allantoic mesoderm in the placenta.

Structure	Level	Pattern	Image	Note
TS17: internal carotid artery	Present	Non-Uniform	3a	Expressed discontinuously.

Structure	Level	Pattern	Image	Note
TS17: dorsal aorta	Present	Regionally restricted	3b	Expressed in a monolayer of smooth muscle cells.

Structure	Level	Pattern	Image	Note
TS17: 3rd arch artery	Weak	Non-Uniform	3c	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS17: 4th arch artery	Weak	Non-Uniform	3d	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS17: ascending aorta	Present		3e	Expressed in the ventral aorta at the midline, nearly formed a monolayer of smooth muscle cells.

Structure	Level	Pattern	Image	Note
TS17: dorsal aorta	Present	Regionally restricted	3f	Expressed in a monolayer of smooth muscle cells. The ventromedial side was more intensely stained.

Structure	Level	Pattern	Image	Note
TS17: umbilical artery extraembryonic part	Present	Regionally restricted	3g	Expressed in two layers of smooth muscle cells. Proximal regions of the radially spreading branches were lined with a monolayer of positive cells. More distal regions were discontinuously stained or not stained.

Structure	Level	Pattern	Image	Note
TS17: dorsal aorta	Present	Regionally restricted	3-IIh	Expressed in a monolayer of smooth muscle cells.

Structure	Level	Pattern	Image	Note
TS17: vitelline artery	Present	Non-Uniform	3-IIi	Discontinuous staining.
TS17: vitelline vein embryonic part	Present	Non-Uniform	3-IIi	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS17: left umbilical artery	Absent		3-IIj

Structure	Level	Pattern	Image	Note
TS17: dorsal aorta	Present	Regionally restricted	3-IIk	Only expressed in the dorsal and ventral parts in the lumbar region.

Structure	Level	Pattern	Image	Note
TS17: artery	Present	Regionally restricted	4b	Several positive cells at sites distant from the branch point of the subclavian arteries.

Structure	Level	Pattern	Image	Note
TS17: artery	Present	Regionally restricted	4c	Several positive cells at sites distant from the branch point of the subclavian arteries.

Structure	Level	Pattern	Image	Note
TS19: artery	Present	Regionally restricted	4d	Discontinuous staining in the right subclavian artery.

Structure	Level	Pattern	Image	Note
TS19: internal carotid artery	Present	Regionally restricted	5a	Expressed in a monolayer of smooth muscle cells. Discontinuous staining in rostral regions.

Structure	Level	Pattern	Image	Note
TS19: 3rd arch artery	Present	Regionally restricted	5b	Expressed in a monolayer of smooth muscle cells.

Structure	Level	Pattern	Image	Note
TS19: 4th arch artery	Present	Regionally restricted	5c	Expressed in a monolayer of smooth muscle cells.

Structure	Level	Pattern	Image	Note
TS19: 6th arch artery	Present	Regionally restricted	5d	Expressed in a monolayer of smooth muscle cells.

Structure	Level	Pattern	Image	Note
TS19: basilar artery	Present	Non-Uniform	5e	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS19: vertebral artery	Present	Non-Uniform	5f	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS19: dorsal aorta	Present	Regionally restricted	5-IIg	Expressed in 2-3 layers of smooth muscle cells at the thoracic region after the point of fusion.

Structure	Level	Pattern	Image	Note
TS19: intersomitic artery	Weak		5-IIh

Structure	Level	Pattern	Image	Note
TS19: vitelline artery	Present	Regionally restricted	5-IIi	Expressed in 1-2 layers of smooth muscle cells.
TS19: vitelline vein embryonic part	Present	Regionally restricted	5-IIi	Expressed in a monolayer of smooth muscle cells at most.

Structure	Level	Pattern	Image	Note
TS19: umbilical artery	Present	Regionally restricted	5-IIj	Expressed in 1-2 layers of smooth muscle cells.
TS19: umbilical vein	Present	Non-Uniform	5-IIj	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS19: ductus venosus	Present	Non-Uniform	5-IIk	Discontinuous staining.

Structure	Level	Pattern	Image	Note
TS15: cardiac muscle tissue	Present
TS15: myotome	Present			In some somites.

Structure	Level	Pattern	Image	Note
TS17: 6th arch artery	Absent
TS17: intersomitic artery	Absent

Structure	Level	Pattern	Image	Note
TS19: dorsal aorta	Present	Regionally restricted		Expressed in a monolayer of smooth muscle cells in the abdominal and lumbar regions, including the joints to the omphalomesenteric artery and the umbilical arteries. Discontinuous staining in the proximal region of the caudal artery.

Structure	Level	Pattern	Image	Note
TS28: smooth muscle tissue	Present
TS28: cardiac muscle tissue	Absent
TS28: skeletal muscle tissue	Absent