Antibody:	anti-ARNT
Detection system:	Biotinylated secondary antibody/[Strept]avidin coupled to horseradish peroxidase

Structure	Level	Pattern	Image	Note
TS17: forebrain	Present	Regionally restricted	1A	Highest expression levels in neuroepithelial cells.
TS17: hindbrain	Present	Regionally restricted	1A	Highest expression levels in neuroepithelial cells.
TS17: midbrain	Present	Regionally restricted	1A	Highest expression levels in neuroepithelial cells.
TS17: neural tube	Present	Regionally restricted	1A	Highest expression levels in neuroepithelial cells.
TS17: branchial arch	Present		1A	Expressed in tissues derived from neuroepithelium and neural crest cells.
TS17: cranial ganglion	Present		1A	Expressed in tissues derived from neuroepithelium and neural crest cells.
TS17: lens placode	Present		1A	Expressed in tissues derived from neuroepithelium and neural crest cells.
TS17: otocyst	Present		1A	Expressed in tissues derived from neuroepithelium and neural crest cells.
TS17: limb ectoderm	Present		1A	Expression was nuclear.
TS17: limb mesenchyme	Present		1A	Expression was nuclear.

Structure	Level	Pattern	Image	Note
TS19: acoustic ganglion	Strong		1C	Expressed in preganglionic complexes. Expression was nuclear.
TS19: facial ganglion	Strong		1C	Expressed in preganglionic complexes. Expression was nuclear.
TS19: trigeminal ganglion	Strong		1C	Expressed in preganglionic complexes. Expression was nuclear.
TS19: limb ectoderm	Present		1C	Expression was nuclear.
TS19: limb mesenchyme	Present		1C	Expression was nuclear.

Structure	Level	Pattern	Image	Note
TS19: heart	Strong		1D	Strong nuclear localization, but cytoplasmic expression was also apparent.
TS19: liver	Present		1D	Cytoplasmic and nuclear expression, which was lower overall than that of the neural cells, but some liver nuclei showed very high expression.

Structure	Level	Pattern	Image	Note
TS19: midbrain	Present		1E	Expression was nuclear.

Structure	Level	Pattern	Image	Note
TS20: mandible primordium	Present	Regionally restricted	1F	Expressed in mandibular epidermis, with nuclear and cytoplasmic localization in the basal cell layer.

Structure	Level	Pattern	Image	Note
TS21: liver	Present		2A	Highest expression. Increased expression compared with E10.5.
TS21: heart	Weak		2A

Structure	Level	Pattern	Image	Note
TS21: brain	Present	Regionally restricted	2C	Expressed in neuroepithelium.
TS21: extrinsic ocular pre-muscle mass	Present		2C
TS21: facial bone primordium	Present		2C
TS21: optic nerve	Present		2C
TS21: tongue	Present		2C
TS21: tooth bud	Present		2C

Structure	Level	Pattern	Image	Note
TS21: choroid plexus	Weak	Regionally restricted	2D	Expressed in both ependymal cells and vascular mesenchyme of the choroid plexus of the 1st and 4th ventricles.

Structure	Level	Pattern	Image	Note
TS22: epidermis	Present		3B	Cytoplasmic and pronounced nuclear expression through most of the epidermal cells.
TS22: integumental system superficial muscle	Present	Regionally restricted	3B	Expressed in muscles underlying the epidermis.

Structure	Level	Pattern	Image	Note
TS22: epidermis	Present		3C	Cytoplasmic and pronounced nuclear expression through most of the epidermal cells.
TS22: integumental system superficial muscle	Present	Regionally restricted	3C	Expressed in muscles underlying the epidermis.

Structure	Level	Pattern	Image	Note
TS23: liver	Strong		4A	Higher expression than other tissues. More of the cells have strong nuclear staining.
TS23: adrenal gland	Strong		4A	Higher expression than other tissues. Expressed high cytoplasmic levels with an absence of nuclear staining in many of the cells.

Structure	Level	Pattern	Image	Note
TS23: epidermis	Strong		4C
TS23: lens	Strong		4C
TS23: tongue	Strong		4C
TS23: facial bone primordium	Strong		4C	Strong nuclear expression.

Structure	Level	Pattern	Image	Note
TS23: tongue muscle	Present		4D	Nuclear expression in the vertical components.
TS23: mandible	Present		4D	Nuclear expression in mandibular bone and cartilage.

Structure	Level	Pattern	Image	Note
TS24: adrenal gland	Present		4E	Highest expression.
TS24: epidermis	Present		4E
TS24: liver	Present		4E

Structure	Level	Pattern	Image	Note
TS19: liver	Present		5A	Relatively high cytoplasmic and nuclear expression, which was lower overall than that of the neural cells, but some liver nuclei showed very high expression.

Structure	Level	Pattern	Image	Note
TS21: liver	Present	Uniform	5B	Expressed in a relatively uniform cytoplasmic and nuclear pattern.

Structure	Level	Pattern	Image	Note
TS24: liver	Present		5C , 5D	Increased nuclear expression. Expressed in a relatively uniform cytoplasmic and nuclear pattern.

Structure	Level	Pattern	Image	Note
TS21: adrenal gland	Strong	Regionally restricted	5E	Expressed in both cytoplasm and nuclei, although some cells had strong nuclear localization, particularly the capsular epithelial cells.

Structure	Level	Pattern	Image	Note
TS22: adrenal cortex	Present	Regionally restricted	5F	Expression was cytoplasmic in the cortical cells organized in linear arrays.

Structure	Level	Pattern	Image	Note
TS24: adrenal gland	Very strong		5G	Expression was cytoplasmic in the cortical cells organized in linear arrays. There were also cortical cells with nuclear expression in these arrays.

Structure	Level	Pattern	Image	Note
TS22: liver	Strong			Increased numbers of strongly positive nuclei compared with E13.5. Highest expression.
TS22: lung	Absent
TS22: facial bone primordium	Present			Expression was nuclear.
TS22: tongue muscle	Present			Expression was nuclear.
TS22: cervical vertebral cartilage condensation	Present			Expressed in developing bones of the thorax. Expression was nuclear.
TS22: limb cartilage condensation	Present			Expressed in developing bones of the limbs. Expression was nuclear.
TS22: forebrain	Present	Regionally restricted		Expressed in the roof.
TS22: midbrain roof plate	Present

Structure	Level	Pattern	Image	Note
TS23: brain	Present			Similar to that of E14.5.
TS23: epidermis	Present			Similar to that of E14.5.
TS23: integumental system superficial muscle	Present			Similar to that of E14.5.
TS23: lung	Absent			Similar to that of E14.5.
TS23: submandibular gland	Present	Regionally restricted		Expressed in cytoplasm and nuclei of epithelial cells.

Structure	Level	Pattern	Image	Note
TS24: lung epithelium	Weak	Regionally restricted		Expressed in tubular epithelial cells.
TS24: metanephros epithelium	Weak			Low to moderate expression.
TS24: urothelium of ureter	Weak			Low to moderate expression.