|
Gene |
Clone |
Species |
Stages |
Anatomy |
frzb2
|
|
xenopus
|
NF stage 9
to
NF stage 10.5
|
endoderm
,
vegetal yolk mass
,
blastocoel
,
dorsal
,
deep
,
[+]
|
frzb2
|
|
xenopus
|
NF stage 10
to
NF stage 12.5
|
mesoderm
,
blastopore lip
,
prechordal plate
,
endoderm
,
head endoderm
,
[+]
|
frzb2
|
|
xenopus
|
NF stage 16
|
prechordal plate
,
endoderm
,
anterior
|
frzb2
|
|
xenopus
|
NF stage 28
|
pronephric mesenchyme
|
|
|
Fig. 4. crescent is expressed in dorsal yolky cells of the blastocoele floor at blastula, in anterior mesendoderm at gastrula, and in the pronephros at tailbud stages. In situ hybridization with a crescent antisense probe was performed on sagittally hemisectioned (A–E,G) or on intact embryos (F,H). (A) Internal view of a hemisectioned blastula (stage 9) showing expression in the yolky dorsal blastocoele floor; most of the transcripts are still nuclear indicating the onset of transcription. (B,C) At later blastula (stages 9.5,10−) crescent labeled cells are found more vegetally in the deep layers of the dorsal endoderm. (D) At the onset of gastrulation (stage 10+) the expression in the deep cells intermingle with a new expression domain in the inner layer of the blastopore lip. (E) At stage 10.5 involuting anterior mesendoderm cells have increased transcript levels, whereas the expression in the leading edge of the dorsal endoderm weakens. (F) Dorsal view of a late gastrula (stage 12) showing expression in the prechordal plate and anterior (pharyngeal) endoderm. (G) Internal view of a late neurula (stage 16) showing strong staining in the anterior endoderm (ae) and in the prechordal plate (pp) underlying the developing forebrain. White arrowhead demarcates the anterior limit of the neural plate or head fold. (H) Late tailbud embryo (stage 28) in lateral view displaying expression in the pronephros (pn); note that expression in anterior endomesoderm has disappeared by this stage. |