Antibody:	C592/7E
Detection system:	Secondary antibody coupled to horseradish peroxidase

Structure	Level	Pattern	Image	Note
TS12: embryo	Present	Regionally restricted	4A	Expression was diffuse in the extreme caudal portion of the embryo.
TS12: allantois	Present	Regionally restricted	4A	Highest expression level was found at the base of the allantois.
TS12: lateral plate mesoderm	Present		4A

Structure	Level	Pattern	Image	Note
TS13: embryo	Present	Regionally restricted	4B	Staining spread to more anterior levels encompassing a larger area than that at the previous stage. Anterior boundary staining was still weak and restricted to a region posterior to the limit of somite condensation.
TS13: neural ectoderm	Present	Regionally restricted	4B	Expression in the mesoderm appeared to be stronger and extended to more anterior levels than in the neurectoderm at this stage.
TS13: embryo mesoderm	Present	Regionally restricted	4B	Expression in the mesoderm appeared to be stronger and extended to more anterior levels than in the neurectoderm at this stage.
TS13: lateral plate mesoderm	Present		4B

Structure	Level	Pattern	Image	Note
TS13: neural tube	Present	Regionally restricted	4C	A more anterior expression boundary was found in the neural tube than in the mesoderm. The anterior boundary of expression in the neural tube was found at the level of the 9th or 10th somite.
TS13: embryo mesoderm	Present	Regionally restricted	4C	A more anterior expression boundary was noted in the neural tube than in the mesoderm. Expression in the mesoderm was located more posterior in the still unsegmented region of the embryo.
TS13: lateral plate mesoderm	Present		4C

Structure	Level	Pattern	Image	Note
TS14: tail bud	Present		4D	Expression extended through the entire tail bud.
TS14: paraxial mesenchyme	Present	Regionally restricted	4D	Expression was detected in the paraxial mesoderm with an anterior boundary at the 14th somite.
TS14: neural tube	Present	Regionally restricted	4D	Expression in the neural tube extended up to the 8th somite. Staining intensified in the region immediately posterior to the 9th somite, coincident with the definitive boundary of expression in the neural tube.
TS14: mesenchyme derived from lateral plate	Present	Regionally restricted	4D	Expression in lateral plate mesoderm extended to more anterior levels up to the region of the future forelimb bud.

Structure	Level	Pattern	Image	Note
TS14: tail bud	Present	Regionally restricted	4E	A posterior expression boundary due to down regulation emerged in the tailbud region.
TS14: mesenchyme derived from lateral plate	Present	Regionally restricted	4E	Expression in lateral plate mesoderm extended to more anterior levels up to the region of the future forelimb bud.

Structure	Level	Pattern	Image	Note
TS15: tail	Present	Regionally restricted	4F	Staining in tail gradually moved to more anterior positions.
TS15: neural tube	Present	Regionally restricted	4F	The posterior expression boundary in the neural tube moved progressively forward. At E9.5 expression extended from the level of somite 10-17.

Structure	Cell Type	Level	Pattern	Image	Note
TS15: tail		Present	Regionally restricted	4G	Staining in tail gradually moved to more anterior positions. Downregulation was not complete; residual staining was observed at the tip of the tailbud.
TS15: paraxial mesenchyme		Present	Regionally restricted	4G	The expression domain in the paraxial mesoderm spanned 7 to 8 somites. Expression was robust from somite 14-20, whereas weak staining was observed in the 13th and occasionally in the 21st somite.
TS15: neural tube		Present	Regionally restricted	4G	The posterior expression boundary in the neural tube moved progressively forward. At E9.5 expression extended from the level of somite 10-17.
TS15: migrating neural crest	migratory neural crest cell	Present	Regionally restricted	4G	Stained migratory neural crest cells were observed adjacent to the Hoxc8-positive neural tube.
TS15: forelimb bud		Present	Ubiquitous	4G	Expression encompassed the entire forelimb bud.

Structure	Cell Type	Level	Pattern	Image	Note
TS15: paraxial mesenchyme		Present	Regionally restricted	4H	The expression domain in the paraxial mesoderm was maintained.
TS15: neural tube		Present	Regionally restricted	4H	The posterior expression boundary in the neural tube moved progressively forward. At E9.5 expression extended from the level of somite 10-17.
TS15: migrating neural crest	migratory neural crest cell	Present		4H

Structure	Level	Pattern	Image	Note
TS17: paraxial mesenchyme	Present	Regionally restricted	4I	The expression domain in the paraxial mesoderm was maintained.
TS17: neural tube	Present	Regionally restricted	4I	The expression domain was from the level of somites 10-15.
TS17: forelimb bud	Weak		4I
TS17: hindlimb bud	Weak		4I
TS17: apical ectodermal ridge	Weak		4I
TS17: limb mesenchyme	Weak		4I