Probe:	Pax1 probe3
Probe preparation:	Antisense labelled with S35 RNA
Visualized with:	Autoradiography
Assay notes:	Hybridization with a paired-box containing fragment (MGI:1309770) and a 3'UTR probe (MGI:28160) gave the same result.

Structure	Level	Pattern	Image	Note
TS16: forelimb bud	Present	Regionally restricted		Expression domain included mesenchyme occupying the anterior proximal region of the forelimb bud and a small outward bulge that is present at the base of the bud at this stage.
TS16: forelimb bud mesenchyme	Present
TS16: trunk sclerotome	Strong	Regionally restricted		Expression levels were higher than in the forelimb.

Structure	Level	Pattern	Image	Note
TS17: forelimb bud mesenchyme	Present	Regionally restricted	1A/A'	Greatest signal intensity was found anterodorsally. Level of expression was similar to that in the sclerotomes.
TS17: forelimb bud ectoderm	Absent		1A/A'
TS17: trunk sclerotome	Present	Regionally restricted	1A/A'

Structure	Level	Pattern	Image	Note
TS17: hindlimb bud mesenchyme	Weak	Regionally restricted	1C/C'	Expression was detected in the anterior proximal mesenchyme of the hindlimb bud.
TS17: trunk mesenchyme	Weak	Regionally restricted	1C/C'	Expression was detected in a longitudinal band of mesenchyme in the lateral region of the trunk. This may correspond to the Wolffian ridge, from which the limb buds originally grow out.

Structure	Level	Pattern	Image	Note
TS20: forelimb mesenchyme	Present	Regionally restricted	2A	Expression was detected in a discrete portion of relatively uncondensed mesenchyme within the anterior proximal forelimb bud.

Structure	Level	Pattern	Image	Note
TS20: shoulder mesenchyme	Present	Regionally restricted	2D	The blastemal scapula blade and spina region corresponds to the dorsal limit of the expression domain.

Structure	Level	Pattern	Image	Note
TS20: shoulder mesenchyme	Present	Regionally restricted	2F/F'	Expression is concentrated in and around the distal end of the acromion blastema.
TS20: forelimb mesenchyme	Present	Regionally restricted	2F/F'	Signal detected in the lower part of the limb bud corresponds to the anterior limit of expression in the lateral trunk.

Structure	Level	Pattern	Image	Note
TS20: shoulder mesenchyme	Weak	Regionally restricted	2H/H'	Expression was very weak in the proximal end of the acromion blastema.

Structure	Level	Pattern	Image	Note
TS20: shoulder mesenchyme	Strong	Regionally restricted	2K	Expression was strong in the newly condensed distal end of the acromion.

Structure	Level	Pattern	Image	Note
TS22: shoulder joint primordium	Present	Regionally restricted	2L/L'	Expression domain extends ventrally into the developing shoulder joint. Signal is distributed around and between the ends of the acromion and clavicle, but not the coracoid process.

Structure	Level	Pattern	Image	Note
TS20: hip mesenchyme	Strong	Regionally restricted	3A/A'	Strong expression is detected in mesoderm at the anterior end of the ileum blastema.

Structure	Level	Pattern	Image	Note
TS21: pelvic girdle skeleton	Strong	Regionally restricted	3C/C'	Expression is detected ventrolateral to the pubis blastema.
TS21: anterior abdominal wall musculature	Weak		3C/C'

Structure	Level	Pattern	Image	Note
TS22: hip	Present	Regionally restricted	3E/E'	Expression is localized around the ischium and pubis anlagen.
TS22: pubis pre-cartilage condensation	Present	Regionally restricted	3E/E'	Expression is localized around the ischium and pubis anlagen.
TS22: anterior abdominal wall musculature	Weak	Regionally restricted	3E/E'	Expression is detected in certain blood vessels in the lower abdominal wall.

Structure	Level	Pattern	Image	Note
TS22: ankle	Present
TS22: elbow joint primordium	Present
TS22: wrist	Present

Structure	Level	Pattern	Image	Note
TS22: knee joint primordium	Present		4A/A'

Structure	Level	Pattern	Image	Note
TS22: future tarsus	Present		4B/B'

Structure	Level	Pattern	Image	Note
TS22: hindlimb interdigital region	Present	Regionally restricted	4C/C'	Expression is detected between the digits.