Antibody:	Isl1 antibody
Detection system:	Secondary antibody coupled to Alexa Fluor 488

Structure	Level	Pattern	Image	Note
TS19: midbrain-hindbrain junction	Present		4A merge , 4A middle

Structure	Level	Pattern	Image	Note
TS19: telencephalon	Present	Regionally restricted	4B merge , 4B middle	Expressed in the basal forebrain. The migrating neurons just leaving the subventricular zone expressed barely detectable protein.
TS19: diencephalon lateral wall mantle layer	Present		4B middle , 4B merge	Expression largely overlapped with LacZ staining in the outer mantle layer where differentiated neurons reside.

Structure	Level	Pattern	Image	Note
TS19: diencephalon	Present		4C merge , 4C middle	The migrating neurons just leaving the subventricular zone expressed barely detectable protein.

Structure	Level	Pattern	Image	Note
TS19: hindbrain	Present	Regionally restricted	4D merge , 4D middle	Expressed in the ventral motor neurons. Barely detectable in the dorsal-lateral motor neurons.

Structure	Level	Pattern	Image	Note
TS19: trigeminal ganglion	Present		4E	A subset of cranial neurons were stained only by Isl1 antibody, but not anti-lacZ.

Structure	Level	Pattern	Image	Note
TS19: acoustic ganglion	Present		4F merge	A subset of cranial neurons were stained only by Isl1 antibody, but not anti-lacZ.
TS19: facial ganglion	Present		4F merge	A subset of cranial neurons were stained only by Isl1 antibody, but not anti-lacZ.

Structure	Level	Pattern	Image	Note
TS19: glossopharyngeal ganglion	Present		4G merge	A subset of cranial neurons were stained only by Isl1 antibody, but not anti-lacZ.
TS19: vagus ganglion	Present		4G merge	A subset of cranial neurons were stained only by Isl1 antibody, but not anti-lacZ.

Structure	Level	Pattern	Image	Note
TS19: branchial arch endoderm	Present		4H merge
TS19: branchial arch mesenchyme	Present		4H merge
TS19: carotid artery	Present		4H merge
TS19: vagus ganglion	Present		4H merge

Structure	Level	Pattern	Image	Note
TS19: dorsal root ganglion	Present		4I
TS19: future spinal cord	Present	Regionally restricted	4I	Expressed in spinal motor neurons.

Structure	Level	Pattern	Image	Note
TS19: arytenoid swelling pre-cartilage condensation	Present		4J
TS19: branchial arch endoderm	Present		4J

Structure	Level	Pattern	Image	Note
TS19: outflow tract	Present		4K merge , 4K middle	Expressed in myocardial cells of the distal outflow tract, albeit at lower levels. Few if any endocardial cells or outflow cushion mesenchymal cells exhibited Isl1 expression.
TS19: outflow tract distal part	Present		4K middle , 4K merge