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Display additional annotations [+]
Gene |
Clone |
Species |
Stages |
Anatomy |
six1
|
|
laevis
|
NF stage 18
|
preplacodal ectoderm
,
pre-chordal neural plate border
,
neural plate border
,
anterior placodal area
,
posterior placodal area
|
tfap2a
|
|
laevis
|
NF stage 16
|
anterior neural fold
,
neural fold
,
preplacodal ectoderm
,
anterior placodal area
|
zic2
|
|
laevis
|
NF stage 16
|
preplacodal ectoderm
,
pre-chordal neural plate border
,
chordal neural plate border
,
neural plate border
,
anterior placodal area
,
[+]
|
sox11
|
|
laevis
|
NF stage 18
|
neuroectoderm
,
pre-chordal neural plate
,
chordal neural plate
,
neural plate
,
cranial placode
,
[+]
|
sox2
|
|
laevis
|
NF stage 18
|
neuroectoderm
,
pre-chordal neural plate
,
chordal neural plate
,
neural plate
,
cranial placode
,
[+]
|
irx1
|
|
laevis
|
NF stage 18
|
neuroectoderm
,
pre-chordal neural plate
,
chordal neural plate
,
neural plate
,
cranial placode
,
[+]
|
foxd3
|
|
laevis
|
NF stage 16
|
neural crest
,
cranial neural crest
,
migratory neural crest cell
,
premigratory neural crest cell
|
foxd3
|
|
laevis
|
NF stage 18
|
neural crest
,
anterior neural fold
,
trunk neural crest
,
cranial neural crest
,
migratory neural crest cell
,
[+]
|
msx1
|
|
laevis
|
NF stage 16
|
anterior neural fold
,
neural fold
,
non-neural ectoderm
,
preplacodal ectoderm
,
anterior placodal area
,
[+]
|
sox9
|
|
laevis
|
NF stage 16
|
neural crest
,
trunk neural crest
,
cranial neural crest
,
migratory neural crest cell
,
preplacodal ectoderm
,
[+]
|
|
|
Pa2G4 gain-of-function enlarges the neural border zone and neural crest at the expense of placodes. (A) Three genes required for neural border zone formation are expanded when the level of Pa2G4 is elevated. Black bars indicate the width of the expression domain on the control side of an embryo, and red bars indicate the width in the same embryo on the side injected with 200 pg of pa2g4 mRNA, indicated by the pink lineage tracer. (B) Three genes required for neural crest formation are expanded (red bars for foxd3, sox9; red arrow for zic2) on the pa2g4 side of the embryos, compared to control sides (black) of the same embryo. For zic2, the neural plate also is expanded (red bar). For sox9, the otic placode domain (red arrow) is reduced. (C) Genes required for cranial placode formation are differentially affected by increasing pa2g4. For six1, a low dose (100 pg) broadens the PPE domain (red bar), whereas 200 pg reduces the intensity of expression (red arrow). The placode domains of sox11 and sox2 are enlarged at both doses (also see Table 2). The placode domain of irx1 is reduced at 100 pg, but either reduced (irx1-200-a) or expanded (irx1-200-b) with 200 pg. The neural plate expression of sox11 and irx1 are expanded (red bars) at either dose. The sox2 neural plate domain infrequently appeared broader, but quantitation verified that it is (see text). foxd4l1 expression is maintained in the neural plate long after it should normally be extinguished (red arrows). (D) Expression of pa2g4 in the precursor of the neural plate (see Fig. 4A) causes the ectopic expression of neural border (msx1) and neural crest (foxd3, zic2) genes in the neural plate midline (red arrows). (E) Co-expression of Six1 with Pa2G4 (left image) eliminates the ectopic neural plate expression of foxd3 (red arrow; cf. 5D) and ameliorates the significant expansion of foxd3 in the border zone (cf. 5B), suggesting that these phenotypes are due to interaction with another factor. Expression of Pa2G4 in the absence of Six1 (right image) preserves the ectopic neural plate (np) expression of foxd3 and broadly expands it past the border zone (bz) into the lateral epidermis (epi). |