Probe:	pSOK10
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography
Assay notes:	Probe specific for type IIA transcripts.

Structure	Level	Pattern	Image	Note
TS21: rib pre-cartilage condensation	Strong	Regionally restricted	5A	Strong expression in arco-costal mesenchymal condensations in the lateral sclerotome.
TS21: paraxial mesenchyme	Moderate		5A	Moderate level of expression in adjacent paraxial mesenchyme
TS21: skin	Present		5A	Expression in the surface ectoderm.

Structure	Level	Pattern	Image	Note
TS21: axial skeleton	Moderate	Regionally restricted	5B	Localized expression in mesenchymal cells and chondrocytes at periphery of the primitive intervertebral disc and in the notochord. Lower expression in the core of the primitive intervertebral disc than in peripheral mesenchyme
TS21: notochord	Present		5B
TS21: trachea mesenchyme	Weak		5B	Much lower level of expression in mesenchyme surrounding the tracheal tube.

Structure	Level	Pattern	Image	Note
TS23: vertebral cartilage condensation	Present	Regionally restricted	5C	Preferential expression in mesenchyme and differentiating chrondrocytes at cranial and caudal aspects of primordial vertebral bodies. No expression in cells in the lateral surface of vertebral body.
TS23: intervertebral disc	Present	Regionally restricted	5C	Expression progressively localized to two annular rings on the rostral and caudal surface of the vertebral body.
TS23: nucleus pulposus	Present	Regionally restricted	5C	Expression in cells forming part of the nucleus pulposus.
TS23: annulus fibrosus	Absent		5C
TS23: axial musculature	Present	Regionally restricted	5C	Expression in ligamentous insertion associated with the vertebrae.
TS23: skin	Present		5C	Expression in surface ectoderm

Structure	Level	Pattern	Image	Note
TS25: vertebra	Present	Regionally restricted	5E	Low levels of expression in fibroblastic cells in the perichondral region and newly recruited chondrocytes of vertebral primordia. No expression in hypertrophic chondrocytes and ossifying tissues.
TS25: axial musculature	Present	Regionally restricted	5E	Expression in the tendinous insertion of the muscle.

Structure	Level	Pattern	Image	Note
TS24: vertebra	Present	Regionally restricted	5G	Expression in articular surfaces of the zygopophyseal joint, spinous ligament and annulus epiphyses of vertebrae.

Structure	Level	Pattern	Image	Note
TS23: basioccipital bone	Present	Regionally restricted	6A	Expression in posterior free edge, intra and extracranial surface of cartilage plate of basi-sphenoid and basi-occipital cartilages; most prominent in inner and outer perichondrial surfaces, and at anterior and posterior free edges.
TS23: basisphenoid bone	Present	Regionally restricted	6A	Expression in posterior free edge, intra and extracranial surface of cartilage plate of basi-sphenoid and basi-occipital cartilages; most prominent in inner and outer perichondrial surfaces, and at anterior and posterior free edges.
TS23: C1 vertebra	Present	Regionally restricted	6A	Expression in epiphyseal growth plates of upper cervical vertebra (C1-C3)
TS23: C2 vertebra	Present	Regionally restricted	6A	Expression in epiphyseal growth plates of upper cervical vertebra (C1-C3)
TS23: C3 vertebra	Present	Regionally restricted	6A	Expression in epiphyseal growth plates of upper cervical vertebra (C1-C3)

Structure	Level	Pattern	Image	Note
TS25: hindlimb digit	Present	Regionally restricted	6C	Expression in the epiphyseal growth plate of hindlimb phalanges, metatarsals and tarsals.
TS25: metatarsus	Present	Regionally restricted	6C	Expression in the epiphyseal growth plate of hindlimb phalanges, metatarsals and tarsals.
TS25: tarsus	Present	Regionally restricted	6C	Expression in the epiphyseal growth plate of hindlimb phalanges, metatarsals and tarsals.

Structure	Level	Pattern	Image	Note
TS23: larynx	Present	Regionally restricted	6D	Uniform distribution of expression in laryngeal mesenchyme.
TS23: laryngeal cartilage	Present	Uniform	6D	Uniform expression in laryngeal and tracheal cartilages.
TS23: trachea cartilaginous ring	Present	Uniform	6D	Uniform expression in laryngeal and tracheal cartilages.

Structure	Level	Pattern	Image	Note
TS26: otic capsule	Present	Regionally restricted	6E	Expression in peripheral chondrocytes of otic capsule
TS26: otic cartilage	Present	Regionally restricted	6E	Expression mostly in the external surface of the otic cartilage.
TS26: inner ear mesenchyme	Weak	Regionally restricted	6E	Lower level of expression in the core mesenchyme.
TS26: inner ear epithelium	Present	Regionally restricted	6E	Expression sensory epithelium of inner ear.
TS26: temporo-mandibular joint	Present	Regionally restricted	6E	Expression in articular cartilage of temporomandibular joint.

Structure	Level	Pattern	Image	Note
TS23: nasal septum mesenchyme	Present	Regionally restricted	6G	Widespread but patchy expression in cartilaginous plate of nasal septum.

Structure	Level	Pattern	Image	Note
TS24: chondrocranium	Weak	Regionally restricted	6H	Lower levels of expression in calvarial mesenchyme.
TS24: diencephalon ventricular layer	Present		6H
TS24: midbrain ventricular layer	Present		6H

Structure	Level	Pattern	Image	Note
TS21: gut epithelium	Present		7A
TS21: lobar bronchus epithelium	Present		7A
TS21: axial skeleton	Strong		7A	Strong expression in vertebral column.

Structure	Level	Pattern	Image	Note
TS17: Rathke's pouch	Strong	Regionally restricted	7B	High level of expression in Rathke's pouch epithelium.
TS17: head mesenchyme	Strong	Regionally restricted	7B	High level of expression cranial mesenchyme adjacent to Rathke's pouch.

Structure	Level	Pattern	Image	Note
TS23: central nervous system	Present	Regionally restricted	7C	Expression in the neuroepithelium of the central nervous system. Rostral expression in floor of brain extended to junction of diencephalon and mesencephalon.
TS23: midbrain-hindbrain junction	Present	Regionally restricted	7C	Expression localized in ventricular cell layer at junction of diencephalon and mesencephalon.

Structure	Level	Pattern	Image	Note
TS22: peripheral nervous system	Absent		7D
TS22: spinal ganglion	Absent		7D
TS22: vertebral cartilage condensation	Strong		7D	High level of expression in cartilage of vertebral column.

Structure	Level	Pattern	Image	Note
TS15: embryo mesenchyme	Present		7E
TS15: heart atrium	Strong	Regionally restricted	7E	Abundant expression in atrium and ventricle. Expression in epimyocardium
TS15: primitive ventricle	Strong	Regionally restricted	7E	Abundant expression in atrium and ventricle. Expression in epimyocardium

Structure	Level	Pattern	Image	Note
TS25: skeleton	Strong	Regionally restricted	7F	Expression in articular surface of developing joints. Strong expression in epiphyseal growth plate on long bone and articular cartilage and ligamentous capsule of shoulder joint.
TS25: vertebral axis musculature	Present	Regionally restricted	7F	Expression in long tendon of extensor and flexor muscles and in ligamentous capsule of the developing joint.

Structure	Level	Pattern	Image	Note
TS13: lateral plate mesoderm	Present	Ubiquitous
TS13: paraxial mesenchyme	Present	Ubiquitous

Structure	Level	Pattern	Image	Note
TS15: tail unsegmented mesenchyme	Present	Uniform
TS15: somite	Present	Regionally restricted		Uniform expression in newly segmented somites. Stronger expression in rostral somites
TS15: sclerotome	Present			Subsequent restriction to sclerotome of differentiating somites.
TS15: head mesenchyme	Strong
TS15: surface ectoderm	Present
TS15: future brain	Present	Regionally restricted		Expression in neuroepithelium of primiitve brain vesicles. Craniocaudal gradient of expression
TS15: future spinal cord	Weak			Higher expression in primitive brain vesicles than in the spinal cord.

Structure	Level	Pattern	Image	Note
TS17: Rathke's pouch	Present
TS17: oral epithelium	Present
TS17: surface ectoderm	Present
TS17: heart atrium	Weak
TS17: primitive ventricle	Weak

Structure	Level	Pattern	Image	Note
TS19: Rathke's pouch	Present
TS19: limb mesenchyme	Present
TS19: oral epithelium	Present

Structure	Level	Pattern	Image	Note
TS21: axial skeleton	Present	Regionally restricted		Expression in medial primitive intervertebral disc condensation. As disc rudiment developes, expression localized to areas of active appositional growth of the mesenchymal mass.
TS21: Meckel's cartilage	Strong	Regionally restricted		Strong expression in mesenchymal condensation of Meckel's cartilage and later in the cartilage.
TS21: limb mesenchyme	Present
TS21: midbrain ventricular layer	Present

Structure	Level	Pattern	Image	Note
TS22: rib cartilage condensation	Present	Regionally restricted		Expression confined to superficial mesenchyme of developing ribs.
TS22: Meckel's cartilage	Present	Patchy
TS22: hindbrain	Present	Regionally restricted		Exprssion extended to include hindbrain floor and rhombic lips.

Structure	Level	Pattern	Image	Note
TS23: rib	Present	Regionally restricted		Expression confined to superficial mesenchyme of developing ribs.
TS23: Meckel's cartilage	Present	Patchy

Structure	Level	Pattern	Image	Note
TS24: rib	Present	Regionally restricted		Expression confined to head and tip of ribs; sparce expression in body of ribs.
TS24: mandible	Present
TS24: laryngeal cartilage	Present	Regionally restricted		Patchy expression localized in peripheral cells of laryngeal cartilage.

Structure	Level	Pattern	Image	Note
TS25: carpus	Present	Regionally restricted		Expression in superficial cells of carpal cartilage
TS25: limb digit	Present	Regionally restricted		Expression localized in proliferating chondrocytes behind the hypertrophic zone in growth plate of long bones and phalanges,
TS25: limb skeleton	Present	Regionally restricted		Expression localized in proliferating chondrocytes behind the hypertrophic zone in growth plate of long bones and phalanges,

Structure	Level	Pattern	Image	Note
TS26: nasal septum	Present	Regionally restricted		Patchy distribution of expression in nasal septum, with marked reduction in levels; mainly localized in superficial perichondrium. No expression in frontal portion of septum.
TS26: inner ear epithelium	Present