Probe:	Mek4 cDNA2
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS17: dermomyotome	Very strong	Regionally restricted	5A	Expression is in the dorsomedial and ventrolateral portions.
TS17: neural tube lateral wall	Present	Regionally restricted	5A	Expression is in a few cells in the subventricular zone.
TS17: mesenchyme derived from lateral plate	Present		5A

Structure	Level	Pattern	Image	Note
TS20: spinal cord lateral wall	Present	Regionally restricted	5B	Expression is in the subventricular zone.
TS20: spinal cord ventral horn	Present	Regionally restricted	5B	Expression is in a subset of cells in the motor neuron pool.

Structure	Level	Pattern	Image	Note
TS23: ventral grey horn	Present	Regionally restricted	5C	Expression is in motor neurons. Highest expression is in the cervical and thoracic regions.

Structure	Level	Pattern	Image	Note
TS20: basal columns	Present	Regionally restricted	6C	Expression is in the medial motor cloumns at the level of the brachial spinal cord.

Structure	Level	Pattern	Image	Note
TS20: basal columns	Present	Regionally restricted	7B	Expression is in a subset of neurons in the medial motor cloumns at the level of the cervical spinal cord.

Structure	Level	Pattern	Image	Note
TS20: skeletal musculature	Present	Regionally restricted	9B	Expression is in a subset of the axial musculature. Expression is seen in the rhomboideus capitis, deltoids, and trapezius and is absent in the splenius capitis, cervicus capitis, rectus cervicis, and subcapsularis.

Structure	Level	Pattern	Image	Note
TS15: mesenchyme derived from lateral plate	Present