Probe:	Gdnf probe9
Probe preparation:	Antisense labelled with P32 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS17: forelimb bud	Weak	Regionally restricted	1A	Low levels of expression in proximal regions of the forelimb bud prior to the time motor and sensory axons reach the limb.

Structure	Level	Pattern	Image	Note
TS17: alimentary system mesenchyme	Present		1B	Expression in tissue surrounding the gastrointestinal system.

Structure	Level	Pattern	Image	Note
TS17: mesonephros	Present	Regionally restricted	1C	Expression in mesonephric ridges in the caudal embryo.

Structure	Level	Pattern	Image	Note
TS19: forelimb bud mesenchyme	Strong	Regionally restricted	2A	Intense expression in a focal region centrally in proximal limb.
TS19: alimentary system mesenchyme	Strong		2A	High levels of expression in mesodermal tissues surrounding the gastrointestinal tract.

Structure	Level	Pattern	Image	Note
TS19: forelimb bud	Strong	Regionally restricted	2B	In many section, a large axon fascicle containing sensory and motor neurons was visible in the middle of a region of expression.

Structure	Level	Pattern	Image	Note
TS19: hindlimb bud	Present	Regionally restricted		Less intense expression in the hindlimb bud, with expression pattern similar to that of forelimb bud.

Structure	Level	Pattern	Image	Note
TS20: trunk	Present	Regionally restricted	3A	Authors state that, in a non-limb region, there is no expression in regions of axons similar to that in the limb.

Structure	Level	Pattern	Image	Note
TS20: forelimb	Present	Regionally restricted	3B	Expression adjacent to axons within peripheral nerve in proximal limb.

Structure	Level	Pattern	Image	Note
TS20: forelimb	Present	Regionally restricted	3C	In the forelimb, expression more restricted compared with E11.5. Expression in cells surounding the peripheral nerves.

Structure	Level	Pattern	Image	Note
TS20: alimentary system mesenchyme	Present			Expression in tissues surrounding the gastrointestinal tract.

Structure	Level	Pattern	Image	Note
TS21: forelimb	Present	Regionally restricted	3G	Focal expression in the limb bud, with levels lower than that seen at E12.5
TS21: peripheral nerve	Present	Regionally restricted	3G	Expression in Schwann cells within the peripheral nerve, most evident at the point where motor fibers exit the spinal cord and in the section of nerve passing through the sclerotome.

Structure	Level	Pattern	Image	Note
TS21: alimentary system mesenchyme	Present			Expression in tissues surrounding the gastrointestinal system.

Structure	Level	Pattern	Image	Note
TS22: forelimb	Present	Regionally restricted		Diminished focal expression in proximal limb.

Structure	Level	Pattern	Image	Note
TS23: forelimb musculature	Strong	Regionally restricted	5A	Prominent expression in several aggregations of muscle tissue.
TS23: forelimb	Present	Regionally restricted	5A	Expression in other regions of the forelimb.

Structure	Level	Pattern	Image	Note
TS23: dermis	Weak	Regionally restricted	5B	Low levels of expression in the dermis of the trunk.
TS23: epidermis	Absent		5B

Structure	Level	Pattern	Image	Note
TS23: forelimb musculature	Present	Regionally restricted	5C	Expression in muscles in the shoulder region, at the proximal end of the humerus, and in the distal limb.

Structure	Level	Pattern	Image	Note
TS23: axial musculature	Absent			No expression in muscle masses in axial regions.
TS23: peripheral nerve	Present	Regionally restricted		Expression in cells within the peripheral nerve, particularly at the point where motor axons exit the ventral spinal cord.