|
Display additional annotations [+]
Gene |
Clone |
Species |
Stages |
Anatomy |
eya1
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
,
trigeminal placode
,
lens placode
,
neural plate
,
lateral
,
[+]
|
six1
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
,
neural crest
,
trigeminal placode
,
lens placode
,
neural plate
,
[+]
|
six4
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
,
trigeminal placode
,
lens placode
,
neural plate
,
lateral
|
pax3
|
|
laevis
|
NF stage 13
to
NF stage 14
|
anterior neural fold
,
cranial neural crest
,
profundal placode
,
neural plate border
|
pax8
|
|
laevis
|
NF stage 13
to
NF stage 14
|
intermediate mesoderm
|
pax6
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
,
chordal neural plate
,
trigeminal placode
,
neural plate
|
sox2
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
,
trigeminal placode
,
neural plate
,
lateral
|
sox3
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
,
chordal neural plate
,
trigeminal placode
,
neural plate
,
profundal placode
,
[+]
|
pax2
|
|
laevis
|
NF stage 13
to
NF stage 14
|
pre-chordal neural plate
|
irx1
|
|
laevis
|
NF stage 13
to
NF stage 14
|
chordal neural plate
,
trigeminal placode
,
lens placode
,
lateral
,
profundal placode
,
[+]
|
msx1
|
|
laevis
|
NF stage 13
to
NF stage 14
|
neural crest
,
trigeminal placode
,
lens placode
,
neural plate
,
profundal placode
,
[+]
|
tbx2
|
|
laevis
|
NF stage 13
to
NF stage 14
|
cement gland primordium
|
dlx3
|
|
laevis
|
NF stage 13
to
NF stage 14
|
ectoderm
,
cement gland primordium
,
trigeminal placode
,
lens placode
,
neural plate border
,
[+]
|
|
|
Fig. 1. Placodal gene expression patterns in neural plate stage Xenopus embryos (stages 13–14) in dorsal view (anterior is to the left, all embryos are equally oriented). To facilitate comparison of the placodal expression domains of different genes, color-coded arrows and arrowheads corresponding to different placodal expression domains of Pax genes are used for the identification of comparable regions of gene expression (for more detailed labeling, see Fig. 12). Colors are explained in the schematic drawing, which depicts the approximate relative position of some gene expression domains and lists the placodes to which they will give rise subsequently. Green arrowheads identify placodal gene expression immediately rostral to the anterior neural plate border (prospective adenohypophysial placode medially and prospective olfactory placodes laterally), whereas green arrows identify placodal gene expression rostrolateral to the anterior neural plate (prospective lens and trigeminal placodes). Black arrows in D indicate the border of Dlx3 expression in superficial ectoderm, which extends further medial than its border of expression in the deep ectodermal layer (colored arrows). Black arrowheads in E indicate Msx1 expression in anterior neural plate. White asterisks in E and L indicate expression of Msx1 and Pax3, respectively, in a region encompassing neural crest and lateralmost neural plate. For detailed description, see text. Abbreviations: Ad/Ol, anterior placodal area, from which adenohypophysial (Ad) and olfactory (Ol) placodes develop; anp, anterior neural plate; cg, cement gland; L, lens placode; LL/Ot/EB, posterior placodal area, from which lateral line (LL), otic (Ot), and epibranchial (EB) placodes develop; np, neural plate; PN, pronephros; Pr, profundal placode; pnp, posterior neural plate; V, trigeminal placode. |
|
Display additional annotations [+]
Gene |
Clone |
Species |
Stages |
Anatomy |
eya1
|
|
laevis
|
NF stage 21
to
NF stage 22
|
olfactory placode
,
otic placode
,
trigeminal placode
|
six1
|
|
laevis
|
NF stage 21
to
NF stage 22
|
olfactory placode
,
otic placode
,
trigeminal placode
|
six4
|
|
laevis
|
NF stage 21
to
NF stage 22
|
olfactory placode
,
otic placode
,
trigeminal placode
,
profundal placode
,
posterior placodal area
|
pax3
|
|
laevis
|
NF stage 21
to
NF stage 22
|
brain
,
forebrain
,
midbrain
,
hindbrain
,
hatching gland
,
[+]
|
pax8
|
|
laevis
|
NF stage 21
to
NF stage 22
|
otic placode
,
pronephric mesenchyme
,
posterior placodal area
|
pax6
|
|
laevis
|
NF stage 21
to
NF stage 22
|
otic vesicle
,
diencephalon
,
spinal cord
,
lens placode
|
sox2
|
|
laevis
|
NF stage 21
to
NF stage 22
|
olfactory placode
,
otic vesicle
,
lens
,
forebrain
,
midbrain
,
[+]
|
sox3
|
|
laevis
|
NF stage 21
to
NF stage 22
|
olfactory placode
,
otic vesicle
,
forebrain
,
midbrain
,
hindbrain
,
[+]
|
pax2
|
|
laevis
|
NF stage 21
to
NF stage 22
|
midbrain-hindbrain boundary
,
otic placode
,
optic vesicle
,
posterior placodal area
|
irx1
|
|
laevis
|
NF stage 21
to
NF stage 22
|
midbrain
,
otic placode
,
trigeminal placode
|
msx1
|
|
laevis
|
NF stage 21
to
NF stage 22
|
hindbrain
,
spinal cord
,
branchial arch
,
otic placode
,
ventral
|
tbx2
|
|
laevis
|
NF stage 21
to
NF stage 22
|
otic vesicle
,
cement gland primordium
,
trigeminal placode
,
lens placode
,
profundal placode
,
[+]
|
dlx3
|
|
laevis
|
NF stage 21
to
NF stage 22
|
olfactory placode
,
cement gland primordium
,
otic placode
,
trigeminal placode
|
|
|
Fig. 9. Placodal gene expression patterns in early tail bud Xenopus embryos (stages 21–22) in lateral views (anterior is to the left) and right frontal views (inserts). Color-coded arrows and arrowheads are used for the identification of comparable regions of gene expression. Expression in the prospective lens placode (which is not yet thickened at this stage) is indicated by L. Colors are explained in the schematic drawing, which shows the distribution of placodes in a stage 21 embryo (modified after Schlosser and Northcutt, 2000; see Fig. 14 for detailed explanation). The unpaired adenohypophysial placode is located medial to the ventral part of the olfactory placode and is, thus, hidden behind the olfactory placode in this lateral perspective (indicated by light green arrow and Ad in brackets). Various shades of green identify placodes (including the prospective lens placode) expressing Pax6, yellow identifies the profundal placode expressing Pax3, and brown and pink jointly identify the posterior placodal area expressing Pax2 and Pax8, with pink being reserved for the subregion, which will form the otic vesicle. Blue–green asterisks indicate downregulation of the respective genes in the region of the prospective lens placode, whereas brown asterisks indicate downregulation of the respective genes in a region intervening between the anterior and posterior subregions of the posterior placodal area. The pink and brown asterisks in I indicate downregulation of FoxI1c expression in the dorsal part of the posterior placodal area. For detailed description, see text. For additional abbreviations, see Fig. 1. |
|
Display additional annotations [+]
Gene |
Clone |
Species |
Stages |
Anatomy |
eya1
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
trigeminal placode
,
epibranchial placode
,
lateral line placode
,
profundal placode
,
[+]
|
six1
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
olfactory placode
,
otic placode
,
epibranchial placode
,
profundus ganglion
,
trigeminal ganglion
,
[+]
|
six4
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
epibranchial placode
,
profundus ganglion
,
trigeminal ganglion
,
lateral line placode
|
pax3
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
hindbrain
,
hatching gland
,
pronephric sinus
,
trigeminal ganglion
|
pax8
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
pronephric duct
,
epibranchial placode
,
pronephric kidney
|
pax6
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
olfactory placode
,
lens
,
diencephalon
,
midbrain
,
spinal cord
,
[+]
|
sox2
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
olfactory placode
,
otic vesicle
,
lens
,
forebrain
,
midbrain
,
[+]
|
sox3
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
olfactory placode
,
otic vesicle
,
lens
,
forebrain
,
midbrain
,
[+]
|
pax2
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
hindbrain
,
midbrain-hindbrain boundary
,
spinal cord
,
pronephric duct
,
[+]
|
irx1
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
midbrain-hindbrain boundary
,
pharyngeal arch
,
branchial arch
,
trigeminal placode
,
[+]
|
msx1
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
lens
,
branchial arch
,
lens placode
,
ventral
,
[+]
|
msx1
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
hindbrain
,
branchial arch
,
ventral
|
tbx2
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
otic vesicle
,
lens
,
branchial arch
,
trigeminal placode
,
optic vesicle
,
[+]
|
dlx3
|
|
laevis
|
NF stage 32
to
NF stage 33 and 34
|
olfactory placode
,
otic vesicle
,
pharyngeal arch
,
epibranchial placode
|
|
|
Fig. 11. Placodal gene expression patterns in late tail bud Xenopus embryos (stages 32–34) in lateral views (anterior is to the left). As in Fig. 9, color-coded arrows and arrowheads are used for the identification of comparable regions of gene expression. Expression in the lens is indicated by L. Colors are explained in the schematic drawing, depicting the distribution of placodes in a stage 33/34 embryo (modified after Schlosser and Northcutt, 2000; see Fig. 14 for detailed explanation). By stage 33/34, the profundal placode has disappeared, the trigeminal placode is shrinking rapidly, the lens placode and otic placode have completely invaginated to form the lens and the otic vesicle, respectively, and the lateral line primordia have begun to extend from the lateral line placodes (Schlosser and Northcutt, 2000). Again, orange and brown double arrows indicate expression of the respective genes in a region encompassing facial epibranchial placode and anteroventral lateral line placode. White asterisks indicate gene expression in the pharyngeal pouches. Green and yellow asterisks indicate gene expression in the trigeminal and profundal ganglia (which are fused proximately), respectively. For detailed description, see text. Abbreviations: bam, branchial arch mesenchyme; L, lens; Ot, otic vesicle; vba, ventral branchial arch region (all three germ layers). For additional abbreviations, see Fig. 1. |