Antibody:	anti-PLF
Detection system:	horseradish peroxidase
Assay notes:	Sections were counterstained with hematoxylin, unless otherwise indicated.

Structure	Level	Pattern	Image	Note
TS20: diencephalon	Present	Regionally restricted	2A	Expression in optic stalk region of diencephalon.
TS20: brain white matter	Present	Regionally restricted	2A	Expression in presumptive pyramidal tract.
TS20: cochlea	Present	Regionally restricted	2A	Expression in cells in upper border cells lining cochlear lumen.

Structure	Level	Pattern	Image	Note
TS20: vertebral cartilage condensation	Weak		2B

Structure	Level	Pattern	Image	Note
TS20: heart atrium	Present		2C	Relatively higher expression in atrium and ventricle of developing heart.
TS20: heart ventricle	Present		2C	Relatively higher expression in atrium and ventricle of developing heart.

Structure	Level	Pattern	Image	Note
TS20: rib pre-cartilage condensation	Weak		2D
TS20: peripheral nerve	Present		2D

Structure	Level	Pattern	Image	Note
TS20: ganglionic eminence	Present	Regionally restricted	3A	Expression in ganglionic eminence. Expression restricted to outer differentiating zones.
TS20: ganglionic eminence ventricular zone	Absent		3A
TS20: telencephalon	Present	Regionally restricted	3A	Expression in septal area.

Structure	Level	Pattern	Image	Note
TS20: ganglionic eminence	Present	Regionally restricted	3B	Expression in ganglionic eminence, restricted to outer differentiating zones.
TS20: ganglionic eminence ventricular zone	Absent		3B
TS20: neocortex	Present	Regionally restricted	3B	Expression in frontal cortex, restricted to outer differentiating zones. No expression in ventricular zone.
TS20: diencephalon	Present	Regionally restricted	3B	Expression in diencephalon optic stalk area.
TS20: brain white matter	Present	Regionally restricted	3B	Expression in pyramidal tract.
TS20: peripheral nerve	Present	Regionally restricted	3B	Expression in lumbosacral nerve.

Structure	Level	Pattern	Image	Note
TS20: medulla oblongata	Present	Regionally restricted	3C	Expression in axon bundles in presumptive medulla. Expression restricted to outer differentiating zones. No expression in ventricular zone.
TS20: glossopharyngeal ganglion	Present	Regionally restricted	3C	Expression in neural processes of glossopharyngeal (IX) and vagus (X) cranial nerve ganglia.
TS20: vagus ganglion	Present	Regionally restricted	3C	Expression in neural processes of glossopharyngeal (IX) and vagus (X) cranial nerve ganglia.
TS20: cochlea	Present		3C
TS20: trigeminal ganglion	Absent		3C

Structure	Level	Pattern	Image	Note
TS20: spinal cord	Present	Regionally restricted	3D	Expression in spinal cord basal and alar plates and marginal zone.

Structure	Level	Pattern	Image	Note
TS20: segmental spinal nerve	Strong	Regionally restricted	3E	Intense expression in segmental axon bundles in the thorax.
TS20: vagus nerve	Strong	Regionally restricted	3E
TS20: dorsal root ganglion	Absent		3E	No expression in sensory neuronal cells of dorsal root ganglion.

Structure	Level	Pattern	Image	Note
TS20: peripheral nerve	Present	Regionally restricted	3F	Expression in peripheral lumbosacral nerve.

Structure	Level	Pattern	Image	Note
TS20: thalamus	Strong	Regionally restricted		Strong expression in dorsal thalamus.
TS20: cerebellum primordium	Strong	Regionally restricted		Strong expression in cerebellum, pons and tectum differentiating field.
TS20: midbrain roof plate	Strong	Regionally restricted		Strong expression in cerebellum, pons and tectum differentiating field.
TS20: pons	Strong	Regionally restricted		Strong expression in cerebellum, pons and tectum differentiating field.
TS20: facial ganglion	Strong	Regionally restricted
TS20: glossopharyngeal nerve	Strong
TS20: trigeminal nerve	Strong
TS20: posterior commissure	Strong
TS20: epithalamus	Weak
TS20: pituitary gland	Weak
TS20: forebrain-midbrain boundary region	Weak	Regionally restricted		Weak expression in pretectal area.

Structure	Level	Pattern	Image	Note
TS21: embryo	Weak	Regionally restricted	4A	Authors report expression is less distinct overall than in 12.5 dpc embryos.
TS21: rib cartilage condensation	Weak		4A
TS21: vertebral cartilage condensation	Weak		4A
TS21: heart	Weak		4A
TS21: ganglionic eminence	Weak	Regionally restricted	4A	Low levels of expression in ganglionic eminence differentiating field.

Structure	Level	Pattern	Image	Note
TS21: allocortex	Strong	Regionally restricted	4B	Strong expression in hippocampus ventricular zone and differentiating zone.
TS21: cochlea	Strong		4B	Strong expression within the cochlea at upper edge of cochlear lumen.Low levels of expression in processes from vagus (X) ganglion.
TS21: vagus ganglion	Weak	Regionally restricted	4B	Faint expression in presumptive pyramidal tract.
TS21: brain white matter	Weak	Regionally restricted	4B	Faint expression in presumptive pyramidal tract.
TS21: medulla oblongata	Weak	Regionally restricted	4B	Faint expression in medullary differentiating field.

Structure	Level	Pattern	Image	Note
TS21: peripheral nerve	Strong	Regionally restricted	4C	Intense expression in lumbosacral nerves passing between developing vertebra.

Structure	Level	Pattern	Image	Note
TS21: thoracic vertebral cartilage condensation	Weak		4D	Faint expression in developing vertebral body located at mid-thoracic level.

Structure	Level	Pattern	Image	Note
TS21: facial ganglion	Strong			Strong expression in ganglia and nerve roots for V, VII, IX and X,
TS21: glossopharyngeal ganglion	Strong			Strong expression in ganglia and nerve roots for V, VII, IX and X,
TS21: trigeminal ganglion	Strong			Strong expression in ganglia and nerve roots for V, VII, IX and X,
TS21: glossopharyngeal nerve	Present
TS21: trigeminal nerve	Present
TS21: vagus nerve	Present
TS21: thalamus	Present	Regionally restricted		Expression in dorsal thalamus.
TS21: cerebellum	Present	Regionally restricted		Expression in diencephalon optic differentiation field and cerebellum and pons differentiating fields.
TS21: diencephalon	Present	Regionally restricted		Expression in diencephalon optic differentiation field and cerebellum and pons differentiating fields.
TS21: pons	Present	Regionally restricted		Expression in diencephalon optic differentiation field and cerebellum and pons differentiating fields.
TS21: pituitary gland	Present
TS21: forebrain-midbrain boundary region	Present	Regionally restricted		Expression in pretectal area.
TS21: spinal cord	Present	Regionally restricted		Expression in spinal cord basal plate. Weak expression in spinal cord alar plate.
TS21: spinal nerve	Present
TS21: posterior commissure	Weak
TS21: midbrain roof plate	Weak	Regionally restricted		Weak expression in tectum differentiating field.

Structure	Level	Pattern	Image	Note
TS24: embryo	Present		5A

Structure	Level	Pattern	Image	Note
TS24: tooth	Strong	Regionally restricted	5B	Robust expression in ameloblasts, odontoblasts, and dental pulp in a tooth.

Structure	Level	Pattern	Image	Note
TS24: rib	Present		5C
TS24: vertebra	Present		5C

Structure	Level	Pattern	Image	Note
TS24: brain	Weak		6A	Authors report dramatically reduced expression in brain structures compared with earlier stages, and compared with spinal and pituitary expression in the same embryos.

Structure	Level	Pattern	Image	Note
TS24: tongue muscle	Strong		6B	Intense expression in taste buds and developing muscle of the tongue.
TS24: tongue papillae	Strong		6B	Intense expression in taste buds and developing muscle of the tongue.

Structure	Level	Pattern	Image	Note
TS24: dorsal root ganglion	Present	Regionally restricted	6C

Structure	Level	Pattern	Image	Note
TS24: dorsal root ganglion	Present	Regionally restricted	6C inset	Authors report cytoplasmic localization in dorsal root ganglion neurons.

Structure	Level	Pattern	Image	Note
TS24: adrenal medulla	Strong		6D
TS24: adrenal cortex	Absent		6D

Structure	Level	Pattern	Image	Note
TS24: spinal nerve	Present	Regionally restricted	6E	Expression in neuronal processes traversing the spinal cord.

Structure	Level	Pattern	Image	Note
TS24: spinal cord ventral horn	Weak		6F	Low levels of cytoplasmic expression in neuronal cell bodies in basal plate (presumptive ventral horn) of spinal cord.

Structure	Level	Pattern	Image	Note
TS24: pituitary gland	Strong	Regionally restricted	6G	Discrete areas of intense expression in at outer edges of pituitary gland.

Structure	Level	Pattern	Image	Note
TS24: forelimb bone	Present	Regionally restricted	7A	Authors report expression in bony collar.
TS24: perichondrium	Absent		7A

Structure	Level	Pattern	Image	Note
TS24: forelimb skeleton	Present	Regionally restricted	7B	Expression in proliferating, prehypertrophic and hypertrophic chondrocytes.

Structure	Level	Pattern	Image	Note
TS24: forelimb mesenchyme	Strong	Regionally restricted	7C	Intense expression in mesenchymal cells (preosteoblasts) in the periosteum. authors report both cytoplasmic and nuclear localization.
TS24: perichondrium	Absent		7C

Structure	Level	Pattern	Image	Note
TS24: forelimb	Present		7D

Structure	Level	Pattern	Image	Note
TS24: facial ganglion	Present
TS24: glossopharyngeal ganglion	Present
TS24: trigeminal ganglion	Present
TS24: vagus ganglion	Present
TS24: glossopharyngeal nerve	Weak
TS24: trigeminal nerve	Weak
TS24: vagus nerve	Weak
TS24: neocortex	Weak	Regionally restricted		Weak expression in frontal cortex differentiating field.
TS24: hippocampus	Weak	Regionally restricted		Weak expression in hippocampus differntiating field and ventricular zone.
TS24: cochlea	Weak
TS24: spinal cord	Weak	Regionally restricted		Weak expression in alar plate of spinal cord.

Structure	Level	Pattern	Image	Note
TS26: embryo	Weak		8A	Authors report expression is much lighter overall than at previous ages. Expression greatly dminitished in central neural tissues.

Structure	Level	Pattern	Image	Note
TS26: vagus nerve	Present	Regionally restricted	8B	Expression in vagus nerve bundles in upper thorax and neck.

Structure	Level	Pattern	Image	Note
TS26: cerebral cortex	Present		8C
TS26: hippocampus	Present		8C

Structure	Level	Pattern	Image	Note
TS26: brain white matter	Weak	Regionally restricted	8D	Expression in processes in white matter (fimbria fornix) suroounding hippocampus and corpus callosum.

Structure	Level	Pattern	Image	Note
TS26: rib	Present	Regionally restricted	8E

Structure	Level	Pattern	Image	Note
TS26: vagus nerve	Present	Regionally restricted	8F	Expression in axonal process of vagus nerve.

Structure	Level	Pattern	Image	Note
TS26: facial ganglion	Present
TS26: glossopharyngeal ganglion	Present
TS26: trigeminal ganglion	Present
TS26: vagus ganglion	Present