Probe:	Sax-1 cDNA2
Probe preparation:	Antisense RNA

Structure	Level	Pattern	Image	Note
TS8: embryo	Absent		1A

Structure	Level	Pattern	Image	Note
TS11: primitive streak	Present	Regionally restricted	1B	Expression first detected around E7-7.5 in NSB (node-streak border).
TS11: embryo ectoderm	Present	Regionally restricted	1B	Expression in and alongside the primitive streak, in cells of the CLE (caudal lateral epiblast).

Structure	Level	Pattern	Image	Note
TS11: primitive streak	Present	Regionally restricted	1C	Expression first detected around E7-7.5 in NSB (node-streak border.
TS11: embryo ectoderm	Present	Regionally restricted	1C	Expression in and alongside the primitive streak, in cells of the CLE (caudal lateral epiblast).

Structure	Level	Pattern	Image	Note
TS11: embryo ectoderm	Present	Regionally restricted	1Ca
TS11: primitive streak	Present	Regionally restricted	1Ca

Structure	Level	Pattern	Image	Note
TS11: embryo ectoderm	Present	Regionally restricted	1Cb
TS11: primitive streak	Present	Regionally restricted	1Cb

Structure	Level	Pattern	Image	Note
TS11: embryo ectoderm	Present	Regionally restricted	1Cc
TS11: primitive streak	Present	Regionally restricted	1Cc

Structure	Level	Pattern	Image	Note
TS13: embryo ectoderm	Present	Regionally restricted	1D , 1E	Expression remained highest in epiblast cells in node region and CLE (caudal lateral epiblast) just posterior to the node.
TS13: neural plate	Present	Regionally restricted	1D , 1E	Anterior to the node, expression in recently generated neural tissue, although at lower levels in midline/floor plate.

Structure	Level	Pattern	Image	Note
TS13: neural plate	Present	Regionally restricted	1Ea	Anterior to the node, expression in recently generated neural tissue, although at lower levels in midline/floor plate.

Structure	Level	Pattern	Image	Note
TS13: embryo ectoderm	Strong	Regionally restricted	1Eb	Expression remained highest in epiblast cells in node region.

Structure	Level	Pattern	Image	Note
TS13: embryo ectoderm	Strong	Regionally restricted	1Ec	Expression remained highest in CLE (caudal lateral epiblast) just posterior to the node.
TS13: primitive streak	Weak	Regionally restricted	1Ec	Lower levels of expression in primitive streak, in cells that ingress to form mesoderm.

Structure	Level	Pattern	Image	Note
TS15: neural tube	Present	Regionally restricted	1F	Anteriorly, expression in cells that have begin to form a neural tube. Anterior limit of expression at level of last formed somite.

Structure	Level	Pattern	Image	Note
TS15: neural tube	Present	Regionally restricted	1Fa	Anteriorly, expression in cells that have begin to form a neural tube.
TS15: notochord	Absent		1Fa

Structure	Level	Pattern	Image	Note
TS15: neural tube	Present		1Fb

Structure	Level	Pattern	Image	Note
TS15: embryo ectoderm	Present	Regionally restricted	1Fc	Posteriorly, expression remain in epiblast cells around the closing posterior neuropore.
TS15: tail mesenchyme	Weak	Regionally restricted	1Fc	Lower levels of expression in mesenchymal cells ingressing through the last remnant of primitive streak as tail bud forms.

Structure	Level	Pattern	Image	Note
TS15: tail mesenchyme	Weak	Regionally restricted	1Fd	Lower levels of expression in mesenchymal cells ingressing through the last remnant of primitive streak as tail bud forms.

Structure	Level	Pattern	Image	Note
TS17: tail neural tube	Present	Regionally restricted	1G	In the tail, expression in continued to be detected in most newly formed neural tube. Anterior limit of expression level of last formed somite.

Structure	Level	Pattern	Image	Note
TS17: tail neural tube	Present	Regionally restricted	1Ga	In the tail, expression in continued to be detected in most newly formed neural tube.

Structure	Level	Pattern	Image	Note
TS17: tail neural tube	Present	Regionally restricted	1Gb	In the tail, expression in continued to be detected in most newly formed neural tube.
TS17: chordamesoderm	Present	Regionally restricted	1Gb	Expression also found in CNH (chordo-neural hinge) region. Expression in a mesenchymal cell group continuous with the ventral neural tube.
TS17: notochord	Absent		1Gb	No expression in notochord component of CNH (chordo-neural hinge).

Structure	Level	Pattern	Image	Note
TS17: tail neural tube	Present	Regionally restricted	1Gc	In the tail, expression in continued to be detected in most newly formed neural tube.

Structure	Level	Pattern	Image	Note
TS17: tail mesenchyme	Weak	Regionally restricted	1Gd	Posteriorly, lower levels of expression in contiguous dorsal tail bud mesenchyme.

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present	Regionally restricted	1H	Expression still detected in newly formed neural tube and contiguous tail bud mesenchyme. Anterior limit of expression at level of last formed somite.

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present		1Ha

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present		1Hb

Structure	Level	Pattern	Image	Note
TS19: tail neural tube	Present		1Hc

Structure	Level	Pattern	Image	Note
TS20: tail spinal cord	Trace		1I	When tail elongation is coming to a halt, expression faded away.

Structure	Level	Pattern	Image	Note
TS17: future spinal cord	Present	Regionally restricted	S1A	Expression in subpopulation of motoneurons in hindbrain and spinal cord.
TS17: hindbrain	Present	Regionally restricted	S1A	Expression in subpopulation of motoneurons in hindbrain and spinal cord.

Structure	Level	Pattern	Image	Note
TS17: future spinal cord	Present		S1Aa , S1Aa inset

Structure	Level	Pattern	Image	Note
TS20: hindbrain	Present	Regionally restricted	S1B	Expression in subpopulation of motoneurons in hindbrain and spinal cord.
TS20: spinal cord	Present	Regionally restricted	S1B	Expression in subpopulation of motoneurons in hindbrain and spinal cord.

Structure	Level	Pattern	Image	Note
TS20: midbrain	Present	Regionally restricted	S1Ba	Expression in medial longitudinal fascicle of midbrain.