XB-IMG-46420
Xenbase Image ID: 46420
|
Fig. 4. Expression of XSix1 in the cranial placodes. (A) Anterior view of stage 17/18 embryo demonstrating XSix1 expression in the primitive placodal region (p) bordering the anterior neural plate (np). Short arrows point to faint staining in the region from which the olfactory placodes originate.(B) Anterior view of stage 21 embryo demonstrating XSix1 expression in olfactory placodes (olf), trigeminal/profundal placode (V) and dorsolateral placodal area (dlp). Note lack of expression in the presumptive lens ectoderm (ple). (C) Horizontal section through stage 21 embryo demonstrating expression in the more anterior trigeminal/profundal placode (V) and the more posterior dorsolateral placodal area (dlp). Arrow points to approximate border between them. nt, neural tube. (D) Horizontal section through stage 21 embryo at level of olfactory placodes (olf). Note lack of staining in ple overlying the optic vesicle (ov). (E) In the stage 32 embryo XSix1 is prominently expressed in the domains corresponding to the olfactory (olf), trigeminal (V), anterodorsal (AD), anteroventral (AV) and facial (VII) placodes. In addition, intense staining is present in the otocyst (oto) and a broad domain associated with both the dorsolateral and epibranchial placodes of the glossopharyngeal and vagus cranial nerves (IX/X), that also includes the posterior lateral line placode. Arrowheads ventral to the somites denote segmented patches of expression that are ectodermal. There also is faint staining in the dorsal and ventral tips of the somites. (F) Coronal section through the olfactory placode (between arrows) of a stage 22 embryo. XSix1 is intensely expressed in both the superficial and deep layers. fb, forebrain. (G) Coronal section through the olfactory placode of a stage 25 embryo. XSix1 is not expressed in the deep germinal layer (arrow). fb, forebrain. (H) Coronal section through the olfactory placode of a stage 39 embryo. XSix1 is confined to the superficial and subjacent cells. Asterisk denotes faintly stained head mesenchymal cells. (I) Transverse section of stage 34 embryo at the most posterior level of the retina (ret and adjacent black pigmented retinal epithelium). The intense XSix1 staining corresponds to the remnant of the trigeminal placode (V), which may be contiguous with the anterodorsal placode (see Fig. 4E). Neither the profundal (Pg) nor trigeminal (Vg) ganglion contains XSix1-expressing cells. (J) Transverse section of stage 34 embryo at level of the otocyst (oto). XSix1 is expressed faintly in the ventromedial wall (arrow) and intensely in the lateral wall of the otocyst. The broad region of intense staining ventral to the otocyst is comprised of several placodes of the IX/X complex. hb, hindbrain. (K) At stage 36/37, faint XSix1 expression is detected in the mesenchyme (*) just deep to the domain of the IX/X placode complex, but differentiating neurons in the vagus ganglion (Xg) do not express XSix1. (L) Stage 28/29 otocyst shows faint staining in the ventromedial wall and intense staining in the lateral wall. Arrow denotes border between otocyst and overlying ectoderm. (M) At stage 38/39, the lateral wall of the otocyst (oto) continues to express high levels of XSix1, as do the epibranchial and lateral line IX/X placodal domains. Arrow denotes border between otocyst and overlying ectoderm. (N) In stage 42 otocyst XSix1 expression is maintained in the lateral wall. The staining in the IX/X placodal domain has resolved into two lateral line primordia (arrows). The IX ganglion (*) does not express the gene. Image published in: Pandur PD and Moody SA (2000) Copyright © 2000. Image reproduced with permission of the Publisher, Elsevier B. V.
Image source: Published Larger Image Printer Friendly View |