Probe:	Sek-3
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS13: lateral plate mesoderm	Present	Regionally restricted	4J/K	Expression was detected in the lateral mesoderm of the head and trunk.
TS13: foregut diverticulum endoderm	Absent		4J/K

Structure	Level	Pattern	Image	Note
TS16: neural tube	Present	Widespread	6A/B	Expression was detected throughout the neural tube.
TS16: future midbrain	Present	Regionally restricted	6A/B	Expression was detected in the ventral midbrain.
TS16: diencephalon	Present		6A/B
TS16: optic stalk	Present		6A/B
TS16: telencephalon	Present		6A/B
TS16: optic cup	Present	Regionally restricted	6A/B	Expression was detected in the posterioventral aspects of the optic cups.

Structure	Level	Pattern	Image	Note
TS16: future midbrain	Present	Regionally restricted	6E/F	Expression was detected in ventral midbrain.
TS16: diencephalon	Present		6E/F
TS16: optic stalk	Present		6E/F
TS16: telencephalon	Present		6E/F
TS16: optic cup	Present	Regionally restricted	6E/F	Expression was detected in the posterioventral aspects of the optic cups.
TS16: future brain	Present	Regionally restricted	6E/F	The domain of elevated expression does not have sharp boundaries but begins just posterior to the apex of the mesencephalic flexure and extends into the ventral telencephalon anterior to the optic stalk.

Structure	Level	Pattern	Image	Note
TS16: central nervous system	Weak	Graded	6G/H	Low level expression was detected throughout the central nervous system with a dorso-ventral gradient.
TS16: dorsal root ganglion	Present		6G/H

Structure	Level	Pattern	Image	Note
TS17: dorsal root ganglion	Present		6I/J
TS17: optic cup	Present	Regionally restricted	6I/J	Expression was detected in the retina.
TS17: head mesenchyme	Present	Regionally restricted	6I/J	Expression was detected in the muscle dorsal to the eye and in the mesenchyme anterior to the eye.
TS17: trunk mesenchyme	Present	Regionally restricted	6I/J	Expression was detected in the mesoderm surrounding the common cardinal vein just posterior to the heart.