Probe:	p-lambda-26
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography
Assay notes:	E17.0 and E18.0 embryo heads were demineralized in 0.5M EDTA for 4 days, dehydrated through grades of ethanol, and cleared in chloroform prior to embedding in wax.

Structure	Level	Pattern	Image	Note
TS15: 1st branchial arch mandibular component mesenchyme derived from neural crest	Present			Text states that Msx2 is expressed in the neural crest-derived mesenchyme of all four branchial arches.
TS15: 1st branchial arch maxillary component mesenchyme derived from neural crest	Present			Text states that Msx2 is expressed in the neural crest-derived mesenchyme of all four branchial arches.
TS15: 2nd branchial arch mesenchyme derived from neural crest	Present			Text states that Msx2 is expressed in the neural crest-derived mesenchyme of all four branchial arches.
TS15: 3rd branchial arch mesenchyme derived from neural crest	Present			Text states that Msx2 is expressed in the neural crest-derived mesenchyme of all four branchial arches.

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mandibular component mesenchyme derived from neural crest	Present	Regionally restricted	1A/B	The expression domain is more restricted to the distal mesenchyme (ie aboral side) of each arch.
TS18: 1st branchial arch maxillary component mesenchyme derived from neural crest	Present	Regionally restricted	1A/B	The expression domain is more restricted to the distal mesenchyme (ie aboral side) of each arch.
TS18: 2nd branchial arch mesenchyme derived from neural crest	Present	Regionally restricted	1A/B	The expression domain is more restricted to the distal mesenchyme (ie aboral side) of each arch.
TS18: 3rd branchial arch mesenchyme derived from neural crest	Present	Regionally restricted	1A/B	The expression domain is more restricted to the distal mesenchyme (ie aboral side) of each arch.
TS18: 4th branchial arch mesenchyme derived from neural crest	Present	Regionally restricted	1A/B	The expression domain is more restricted to the distal mesenchyme (ie aboral side) of each arch.
TS18: fronto-nasal process	Present		1A/B
TS18: head mesenchyme	Present	Regionally restricted	1A/B	Expression in the mesenchyme surrounding the otic vesicle and beneath the cranial ectoderm.

Structure	Level	Pattern	Image	Note
TS18: latero-nasal process mesenchyme	Present		2B
TS18: medial-nasal process mesenchyme	Present		2B
TS18: 1st branchial arch maxillary component mesenchyme	Present		2B	A concentration of expression below the area of future first molar tooth initiation.
TS18: 1st branchial arch mandibular component mesenchyme	Present	Regionally restricted	2B	Expression in the oral half of the mandibular process.
TS18: 1st branchial arch mandibular component ectoderm	Absent		2B
TS18: 1st branchial arch maxillary component ectoderm	Absent		2B

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mandibular component mesenchyme	Present	Regionally restricted	3A/D	The domain of Msx2 labeling becomes progressively narrower and more focused, moving proximally into more posterior regions of the head. This domain corresponds to the area where the first molar will develop at a later date.
TS18: 1st branchial arch maxillary component mesenchyme	Present	Regionally restricted	3A/D	The domain of Msx2 labeling becomes progressively narrower and more focused, moving proximally into more posterior regions of the head. This domain corresponds to the area where the first molar will develop at a later date.
TS18: 1st branchial arch mandibular component ectoderm	Absent		3A/D
TS18: 1st branchial arch maxillary component ectoderm	Absent		3A/D

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mandibular component mesenchyme	Present	Regionally restricted	3B/E	The domain of Msx2 labeling becomes progressively narrower and more focused, moving proximally into more posterior regions of the head. This domain corresponds to the area where the first molar will develop at a later date.
TS18: 1st branchial arch maxillary component mesenchyme	Present	Regionally restricted	3B/E	The domain of Msx2 labeling becomes progressively narrower and more focused, moving proximally into more posterior regions of the head. This domain corresponds to the area where the first molar will develop at a later date.
TS18: 1st branchial arch mandibular component ectoderm	Absent		3B/E
TS18: 1st branchial arch maxillary component ectoderm	Absent		3B/E

Structure	Level	Pattern	Image	Note
TS18: 1st branchial arch mandibular component mesenchyme	Present	Regionally restricted	3C/F	The domain of Msx2 labeling becomes progressively narrower and more focused, moving proximally into more posterior regions of the head. This domain corresponds to the area where the first molar will develop at a later date.
TS18: 1st branchial arch maxillary component mesenchyme	Present	Regionally restricted	3C/F	The domain of Msx2 labeling becomes progressively narrower and more focused, moving proximally into more posterior regions of the head. This domain corresponds to the area where the first molar will develop at a later date.
TS18: 1st branchial arch mandibular component ectoderm	Absent		3C/F
TS18: 1st branchial arch maxillary component ectoderm	Absent		3C/F

Structure	Level	Pattern	Image	Note
TS20: mandibular process	Present	Regionally restricted	4A/B	Expression in the dental placode (a small area of epithelial cells a few microns buccal to the thickening dental epithelium) and in the adjacent mesenchyme.
TS20: mandibular process mesenchyme	Present	Regionally restricted	4A/B	Expression in the dental placode (a small area of epithelial cells a few microns buccal to the thickening dental epithelium) and in the adjacent mesenchyme.
TS20: oral epithelium	Present	Regionally restricted	4A/B	Expression in the dental placode (a small area of epithelial cells a few microns buccal to the thickening dental epithelium) and in the adjacent mesenchyme.

Structure	Level	Pattern	Image	Note
TS20: mandibular process	Present	Regionally restricted	5B	Expression in the dental placode epithelia into the buccal aspect of the external enamel epithelia of the inavginating bud stage tooth germ.
TS20: maxillary process	Present	Regionally restricted	5B	Expression in the dental placode epithelia into the buccal aspect of the external enamel epithelia of the inavginating bud stage tooth germ.

Structure	Level	Pattern	Image	Note
TS23: lower jaw molar dental papilla	Present	Regionally restricted	6A/B	Expression in the dense epithelium of the enamel knot, the immediately adjacent internal enamel epithelium and in sub-adjacent layer of dental papilla mesenchyme cells, the region of the buccal external enamel epithelium derived from the dental placode.
TS23: lower jaw molar enamel organ	Present	Regionally restricted	6A/B	Expression in the dense epithelium of the enamel knot, the immediately adjacent internal enamel epithelium and in sub-adjacent layer of dental papilla mesenchyme cells, the region of the buccal external enamel epithelium derived from the dental placode.
TS23: enamel knot	Present		6A/B
TS23: inner enamel epithelium	Present		6A/B

Structure	Level	Pattern	Image	Note
TS24: lower jaw molar dental papilla	Present	Regionally restricted	7A/B	Expression in the buccal and lingual external enamel epithelia, the cellular condensations of the stellate reticulum, by the cervical loops, the stratum intermedium and dental papilla mesenchyme.
TS24: lower jaw molar enamel organ	Present	Regionally restricted	7A/B	Expression in the buccal and lingual external enamel epithelia, the cellular condensations of the stellate reticulum, by the cervical loops, the stratum intermedium and dental papilla mesenchyme.
TS24: outer enamel epithelium	Present		7A/B
TS24: stellate reticulum	Present		7A/B
TS24: stratum intermedium	Present		7A/B

Structure	Level	Pattern	Image	Note
TS25: lower jaw molar enamel organ	Present	Regionally restricted	7D/E	Expression in the stratum intermedium and condensed stellate reticulum in the cervical loops of the enamel organ.
TS25: cervical loop	Present		7D/E
TS25: stellate reticulum	Present		7D/E
TS25: stratum intermedium	Present		7D/E
TS25: lower jaw molar dental papilla	Weak		7D/E

Structure	Level	Pattern	Image	Note
TS26: lower jaw molar dental papilla	Strong	Regionally restricted	8A/B	Strong expression in the odontoblastic and sub-odontoblastic layers of the dental papilla mesenchyme. Expression is absent from the central and apical regions of the dental papilla mesenchyme.

Structure	Level	Pattern	Image	Note
TS20: maxillary process epithelium	Present	Regionally restricted	10A/B	Expression in the anterior incisor region. Expression in the invaginating dental epithelium (dental lamina, dental placode) and adjacent oral epithelium, particularly on the buccal side (o).
TS20: oral epithelium	Present	Regionally restricted	10A/B	Expression in the anterior incisor region. Expression in the invaginating dental epithelium (dental lamina, dental placode) and adjacent oral epithelium, particularly on the buccal side (o).

Structure	Level	Pattern	Image	Note
TS21: lower jaw incisor epithelium	Present	Regionally restricted	11A/B	Expression in the enamel organ, throughout the entire length of the external enamel epithelia on the buccal and cervical surfaces and in the cervical half of the lingual external enamel epithelia.

Structure	Level	Pattern	Image	Note
TS24: lower jaw incisor enamel organ	Present		12A
TS24: upper jaw incisor enamel organ	Present		12A
TS24: lower jaw incisor dental papilla	Present		12A
TS24: upper jaw incisor dental papilla	Present		12A
TS24: oral epithelium	Present	Regionally restricted	12A	Strong expression in the oral epithelia overlying the incisor dental lamina, especially buccal to the laminae.
TS24: hair follicle	Present		12A
TS24: vibrissa	Present		12A

Structure	Level	Pattern	Image	Note
TS24: lower jaw incisor dental papilla	Present	Regionally restricted	13A/B	Expression in the dental papilla mesenchyme, stellate reticulum and external enamel epithelia of the incisor tooth germ on all sides, but is absent from the internal enamel epithelia.
TS24: lower jaw incisor enamel organ	Present	Regionally restricted	13A/B	Expression in the dental papilla mesenchyme, stellate reticulum and external enamel epithelia of the incisor tooth germ on all sides, but is absent from the internal enamel epithelia.
TS24: outer enamel epithelium	Present		13A/B
TS24: stellate reticulum	Present		13A/B
TS24: inner enamel epithelium	Absent		13A/B

Structure	Level	Pattern	Image	Note
TS26: lower jaw incisor dental papilla	Present	Regionally restricted	14A/B	Expression in the odontoblasts and dental papilla mesenchyme cells and the narrow epithelia of the stratum intermedium, stellate reticulum and external enamel epithelia.
TS26: lower jaw incisor enamel organ	Present	Regionally restricted	14A/B	Expression in the odontoblasts and dental papilla mesenchyme cells and the narrow epithelia of the stratum intermedium, stellate reticulum and external enamel epithelia.
TS26: outer enamel epithelium	Present		14A/B
TS26: stellate reticulum	Present		14A/B
TS26: stratum intermedium	Present		14A/B

Structure	Level	Pattern	Image	Note
TS21: cranium	Strong		15B
TS21: diencephalon meninges	Strong		15B	Expression in the cellular precursors of the meninges.
TS21: hindbrain meninges	Strong		15B	Expression in the cellular precursors of the meninges.
TS21: midbrain meninges	Strong		15B	Expression in the cellular precursors of the meninges.
TS21: telencephalon meninges	Strong		15B	Expression in the cellular precursors of the meninges.
TS21: lateral ventricle choroid plexus	Present	Regionally restricted	15B	Expression in the neural epithelium of the lateral choroid plexus.

Structure	Level	Pattern	Image	Note
TS21: vomeronasal organ epithelium	Present	Regionally restricted	16B	Expression in the thinning epithelia and adjacent mesenchymal condensation on the nasal side of Jacobson's organs.
TS21: vomeronasal organ mesenchyme	Present	Regionally restricted	16B	Expression in the thinning epithelia and adjacent mesenchymal condensation on the nasal side of Jacobson's organs.

Structure	Level	Pattern	Image	Note
TS23: vomeronasal organ epithelium	Present	Regionally restricted	16E	Expression in the thinning epithelia and adjacent mesenchymal condensation on the nasal side of Jacobson's organs.
TS23: vomeronasal organ mesenchyme	Present	Regionally restricted	16E	Expression in the thinning epithelia and adjacent mesenchymal condensation on the nasal side of Jacobson's organs.

Structure	Level	Pattern	Image	Note
TS25: vomeronasal organ epithelium	Present	Regionally restricted	16H	Expression in the thinning epithelia and adjacent mesenchymal condensation on the nasal side of Jacobson's organs.
TS25: vomeronasal organ mesenchyme	Present	Regionally restricted	16H	Expression in the thinning epithelia and adjacent mesenchymal condensation on the nasal side of Jacobson's organs.

Structure	Level	Pattern	Image	Note
TS20: adenohypophysis	Absent
TS20: endolymphatic appendage	Present