Probe:	semA probe2
Probe preparation:	labelled with S35 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS17: future spinal cord	Absent			No expression in thoracic spinal cord at this stage. v

Structure	Level	Pattern	Image	Note
TS19: neural tube ventricular layer	Present	Regionally restricted		Expression in ventral half of ventricular zone.
TS19: neural tube marginal layer	Absent

Structure	Level	Pattern	Image	Note
TS20: spinal cord ventricular layer	Present	Regionally restricted	2A	Expression in ventral ventricular zone.
TS20: spinal cord marginal layer	Absent		2A
TS20: segmental spinal nerve	Present	Regionally restricted	2A	Expression in ventral roots.

Structure	Level	Pattern	Image	Note
TS20: spinal cord ventricular layer	Present	Regionally restricted	3A	Expression in ventral half of ventricular zone.
TS20: spinal cord marginal layer	Absent		3A
TS20: segmental spinal nerve	Present	Regionally restricted	3A	Expression in ventral roots.

Structure	Level	Pattern	Image	Note
TS21: thoracic dorsal root ganglion	Strong	Regionally restricted	3B	Strong expression in dorsal and ventral roots of dorsal root ganglia.

Structure	Level	Pattern	Image	Note
TS22: thoracic dorsal root ganglion	Strong	Regionally restricted	3C	Strong expression in dorsal and ventral roots of dorsal root ganglia.

Structure	Level	Pattern	Image	Note
TS23: thoracic dorsal root ganglion	Strong	Regionally restricted	3D
TS23: thoracic vertebra	Present	Regionally restricted	3D	Expression in perichondrium of neural arches.

Structure	Level	Pattern	Image	Note
TS21: trigeminal nerve	Present		3E	Expression in nerves of cranial ganglia, such as the trigeminal ganglion.

Structure	Level	Pattern	Image	Note
TS23: cranial nerve	Present		3G , 3F

Structure	Level	Pattern	Image	Note
TS23: cranial nerve	Present		4A
TS23: limb musculature	Present		4A	Expression in segmentally organized muscle and muscles of appendicular akeleton.
TS23: vertebral axis musculature	Present		4A	Expression in segmentally organized muscle and muscles of appendicular akeleton.

Structure	Level	Pattern	Image	Note
TS20: brain	Present

Structure	Level	Pattern	Image	Note
TS23: choroid plexus	Present		6A	Expression restricted to choroid plexus.