Probe:	ET-A
Probe preparation:	Antisense labelled with S35 RNA

Structure	Level	Pattern	Image	Note
TS15: facio-acoustic preganglion complex	Strong		1A	Expression was detected in the facio-acoustic neural crest complex.
TS15: 1st branchial arch mesenchyme	Present		1A
TS15: 1st branchial arch	Present	Regionally restricted	1A	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.
TS15: migrating neural crest	Present		1A	Expression was detected in migrating cephalic neural crest cells extending from the hindbrain into the pharyngeal arches.
TS15: trunk mesenchyme	Present		1A

Structure	Level	Pattern	Image	Note
TS15: head mesenchyme derived from neural crest	Present		1C
TS15: trunk mesenchyme	Present		1C
TS15: 1st branchial arch mesenchyme	Present		1C
TS15: 2nd branchial arch mesenchyme	Present		1C
TS15: 1st branchial arch	Present	Regionally restricted	1C	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.
TS15: 2nd branchial arch	Present	Regionally restricted	1C	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.

Structure	Level	Pattern	Image	Note
TS15: head mesenchyme derived from neural crest	Present		1E
TS15: trunk mesenchyme	Present		1E
TS15: 1st branchial arch mesenchyme	Present		1E
TS15: 3rd branchial arch mesenchyme	Present		1E
TS15: 2nd branchial arch mesenchyme derived from neural crest	Present	Non-Uniform	1E	Expression in the 2nd arch mesenchyme is less abundant in the core.
TS15: 1st branchial arch	Present	Regionally restricted	1E	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.
TS15: 2nd branchial arch	Present	Regionally restricted	1E	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.
TS15: 3rd branchial arch	Present	Regionally restricted	1E	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.

Structure	Level	Pattern	Image	Note
TS15: head mesenchyme derived from neural crest	Present		1G
TS15: trunk mesenchyme	Present		1G
TS15: 1st branchial arch mesenchyme	Present		1G
TS15: 2nd branchial arch mesenchyme	Present		1G
TS15: 3rd branchial arch mesenchyme	Present		1G
TS15: 1st branchial arch	Present	Regionally restricted	1G	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.
TS15: 2nd branchial arch	Present	Regionally restricted	1G	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.
TS15: 3rd branchial arch	Present	Regionally restricted	1G	Expression was detected in the mesenchyme of pharyngeal arches, but the arch epithelium was negative.

Structure	Level	Pattern	Image	Note
TS13: bulbus cordis	Strong
TS13: common atrial chamber cardiac muscle	Strong
TS13: primitive ventricle cardiac muscle	Strong
TS13: arterial system	Strong	Regionally restricted		Abundant expression was also found in the mesenchyme of the aortic arch.

Structure	Level	Pattern	Image	Note
TS15: neural tube	Absent

Structure	Level	Pattern	Image	Note
TS15: bulbus cordis	Strong		7E
TS15: common atrial chamber cardiac muscle	Strong		7E
TS15: primitive ventricle cardiac muscle	Strong		7E
TS15: arterial system	Strong	Regionally restricted	7E	Abundant expression was also found in the mesenchyme of the aortic arch.