Probe:	Pax2 cDNA3
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography

Structure	Level	Pattern	Image	Note
TS13: embryo	Absent			No expression detected in any ectodermal or mesodermal structures.

Structure	Level	Pattern	Image	Note
TS15: otocyst	Present	Regionally restricted		Earliest expression in otic vesicles.

Structure	Level	Pattern	Image	Note
TS17: brain	Present	Regionally restricted		Earliest detectable of expression within neural tube; expression along boundaries of two primary divisions of neural tube.
TS17: neural tube	Present	Regionally restricted		Earliest detectable of expression within neural tube; expression along boundaries of two primary divisions of neural tube.

Structure	Level	Pattern	Image	Note
TS17: hindbrain	Present	Regionally restricted	1A/B	Sharp rostral limit of expression at mesencephalon-rhombencephalon border (isthmus); continuous expression through rhombencephalon.

Structure	Level	Pattern	Image	Note
TS17: neural tube lateral wall	Present	Regionally restricted	1C/D	Expression in 2 regions, on either side of ventrodorsal midline (sulcus limitans); continuous longitudinal stripes in basal and alar plates

Structure	Level	Pattern	Image	Note
TS17: neural tube lateral wall	Present	Regionally restricted	2A/B	Expression in 2 regions, on either side of ventrodorsal midline (sulcus limitans); continuous longitudinal stripes in basal and alar plates
TS17: neural tube floor plate	Absent		2A/B	No expression in cells in ventral 1/4 of ventricular zone, as well as in progeny in ventral and lateral intermediate zones.

Structure	Level	Pattern	Image	Note
TS19: neural tube lateral wall	Present	Regionally restricted	2C/D	Expression in ventricular zone restricted to 2 compartments bordering sulcus limitans.
TS19: neural tube alar columns	Present	Regionally restricted	2C/D	Clusters of expressing cells in intermediate zone of both basal and alar plates immediately radial to position of transcripts in ventricular zone.
TS19: neural tube basal columns	Present	Regionally restricted	2C/D	Clusters of expressing cells in intermediate zone of both basal and alar plates immediately radial to position of transcripts in ventricular zone.

Structure	Level	Pattern	Image	Note
TS20: spinal cord lateral wall	Present	Regionally restricted	2E/F	Continuous expression along entire dorsal 2/3 of ventricular zone. In intermediate zone, expression restricted to 2 regions extending radially on both sides of sulcus limitans.
TS20: alar columns	Present	Regionally restricted	2E/F	In alar plate, transcripts are present over entire intermediate zone with highest density along its most lateral border.
TS20: basal columns	Present	Regionally restricted	2E/F	In basal plate, signal is seen over cells that have settled medial and dorsal to nonexpressing and earlier formed putative motor neuroblasts.

Structure	Level	Pattern	Image	Note
TS21: spinal cord lateral wall	Present	Regionally restricted	2G/H	In the nearly completely regressed ventricular zone, transcripts are expressed in dorsal 2/3.
TS21: basal columns	Present	Regionally restricted	2G/H	In intermediate zone of basal plate, expression restricted to cells medial and dorsal to nonexpressing motoneuroblasts.
TS21: alar columns	Present	Regionally restricted	2G/H	In intermediate zone of alar plate, highest expression in band of cells extending across midlateral region; also in most dorsolateral alar plate (dorsal region of the dorsal horn, substantia gelatinosa).

Structure	Level	Pattern	Image	Note
TS22: spinal cord lateral wall	Present	Regionally restricted	3A/B	Authors state that transcripts are expressed in the same population of cells as described on previous days; no expression in intermediate central grey.
TS22: basal columns	Present	Regionally restricted	3A/B	In basal plate, expression in cells in intermediate grey, pars ventralis, a region medial and dorsal to putative non-expressing motor neuroblasts.
TS22: alar columns	Present	Regionally restricted	3A/B	In alar plate, transcripts are in basically the same pattern as on day 12; expression in intermediate grey, pars dorsalis, and in a region extending medially from central canal to most dorsolateral region (substantia gelatinosa).
TS22: spinal cord ventricular layer	Absent		3A/B	No expression in ependymal cells lining lumen of neural tube.

Structure	Level	Pattern	Image	Note
TS26: spinal cord lateral wall	Present	Regionally restricted	3C/D	Authors report that the pattern of hybridization appears basically the same as described for day 14.

Structure	Level	Pattern	Image	Note
TS17: hindbrain ventricular layer	Present	Regionally restricted	4A/B	Expression was detected in the ventricular zone in 2 clusters on either side of the ventrodorsal midline, restricted to the outer 1/2 to 1/4 of the ventricular zone. No detectable hybridization in the most ventral and dorsal regions of ventricular zone.
TS17: otocyst	Present	Regionally restricted	4A/B	Level of expression in otic vesicle is higher than on previous day; restricted to side of otic vesicle flanking the neural tube.

Structure	Level	Pattern	Image	Note
TS19: myelencephalon lateral wall	Present	Regionally restricted	4C/D	Expression on either side of dorsoventral midline and in intermediate zone; no expression in regions of intermediate zone that will form intermediate central grey and motor columns.
TS19: saccule	Present	Regionally restricted	4C/D	High-intensity hybridization in more ventral region of otic vesicle which forms the saccular and cochlear (neurogenic) portions of the ear.
TS19: endolymphatic appendage	Absent		4C/D	Not detected in more dorsal regions, which forms the endolymphatic sac.

Structure	Level	Pattern	Image	Note
TS15: optic vesicle	Present	Regionally restricted	5A/B	Expression first detected in the eye; hybridization in most distal region of optic vesicle, apposed to surface ectoderm.
TS15: future brain	Absent		5A/B	Authors report no detectable expression in neural tube.
TS15: neural tube	Absent		5A/B	Authors report no detectable expression in neural tube.

Structure	Level	Pattern	Image	Note
TS16: optic cup	Present	Regionally restricted	5C/D	Expression in ventral 1/2 to 2/3 of invaginating germinal epithelial layer, and ventral region of optic stalk; ends abruptly at border with diencephalon.
TS16: optic stalk	Present	Regionally restricted	5C/D	Expression in ventral 1/2 to 2/3 of invaginating germinal epithelial layer, and ventral region of optic stalk; ends abruptly at border with diencephalon.

Structure	Level	Pattern	Image	Note
TS16: optic cup	Present	Regionally restricted	5E/F	Expression in ventral 1/2 to 2/3 of invaginating germinal epithelial layer, and ventral region of optic stalk; ends abruptly at border with diencephalon.
TS16: optic stalk	Present	Regionally restricted	5E/F	Expression in ventral 1/2 to 2/3 of invaginating germinal epithelial layer, and ventral region of optic stalk; ends abruptly at border with diencephalon.

Structure	Level	Pattern	Image	Note
TS18: neural retinal epithelium	Present	Regionally restricted	5G/H	High levels of expression detected in base of optic cup, and along ventral region of optic stalk extending proximally to border with diencephalon.
TS18: optic stalk	Present	Regionally restricted	5G/H	High levels of expression detected in base of optic cup, and along ventral region of optic stalk extending proximally to border with diencephalon.

Structure	Level	Pattern	Image	Note
TS18: neural retinal epithelium	Present	Regionally restricted	5I/J	High levels of expression detected in base of optic cup, and along ventral region of optic stalk extending proximally to border with diencephalon.
TS18: optic stalk	Present	Regionally restricted	5I/J	High levels of expression detected in base of optic cup, and along ventral region of optic stalk extending proximally to border with diencephalon.

Structure	Level	Pattern	Image	Note
TS22: optic disc	Strong	Regionally restricted	6A/B	Strong expression in optic disc and extending along the entire optic nerve.
TS22: optic nerve	Strong	Regionally restricted	6A/B	Strong expression in optic disc and extending along the entire optic nerve.
TS22: neural retinal epithelium	Absent		6A/B	No expression in neuroblastic layer.

Structure	Level	Pattern	Image	Note
TS26: optic disc	Present	Regionally restricted	6D/E
TS26: optic stalk	Present	Regionally restricted	6D/E
TS26: neural retina	Present	Regionally restricted	6D/E	Expression in a thin layer of cells along the vitreal border of the neuroblastic layers.

Structure	Level	Pattern	Image	Note
TS26: optic disc	Present		6F
TS26: optic stalk	Present		6F
TS26: neural retina	Present	Regionally restricted	6F	Expression in a thin layer of cells along the vitreal border of the neuroblastic layers.

Structure	Level	Pattern	Image	Note
TS22: cochlea	Present
TS22: saccule	Present

Structure	Level	Pattern	Image	Note
TS28: diencephalon	Absent
TS28: optic tract	Absent
TS28: spinal cord	Absent