| |
Fig. 3. N-cadherin expression in the CNS, placodes, and mesodermal
derivatives. A: Oblique section through the rhombencephalic region of
the head in Xenopus tailbud stage (26-27 NF). The rhombencephalon
(see also Fig. 5), the optic vesicle (see C), the lens placode (see C), the
otic vesicle (arrowhead), the notochord, and the hyoid segment (arrow)
show strong hybridization with the N-cadherin probe. 5: Transverse section
through the trunk of the same embryo. Note the intense N-cadherin
expression in the spinal chord (arrow) and in the notochord (arrowhead)
compared to the weak staining of the surrounding somites and epidermis.
C: Detail of A. The eye cup with invaginated retinal layer is homogeneously
labeled and the lens rudiment (arrow) is still part of the sensorial
layer of the ectoderm. Epidermis and neural crest cells (arrowhead) are
negative. D: Transverse section through the retina of a stage 42 NF
Xenopus tadpole. The three layers of neurona! cell bodies express Ncadherin
transcripts; very few grains are visible in the inner and outer
plexiform layers and in the outer segment of the photoreceptors. At the
periphery, where layers have not yet formed, expression of N-cadherin
RNAs is higher (arrow). Note the surrounding black pigmented retinal
epithelium (PE). E: Transverse section of the retina of a Xenopus late
tadpole (50 NF). Layers of cell bodies hybridize with N-cadherin probe. F:
The olfactory placode of a stage 42 Xenopus tadpole expresses high
levels of N-cadherin RNAs (arrowhead). In the connecting double-layered
epidermis, very few grains are present only in the sensorial layer
(arrows). G: Parasagittal section of a Xenopus tailbud (31/32 NF) showing
a weak labeling in the myotomes. Elongated mononucleated myoblasts
(arrow) lie parallel to the axis. H: Xenopus late tailbud (42 NF)
showing numerous grains in myoblasts and myotube forming cells
(arrow) and virtually no reaction in the epidermis (arrowhead). GCL: ganglion
cell layer; IPL: inner plexiform layer; INL: inner nuclear layer; OPL:
outer plexiform layer; ONL: outer nuclear layer; 0s: outer segment of the
photoreceptors; PE: pigment retinal epithelium. A,B,C: dark field optic;
D,E,F,G,H: bright field optic. A: 65 x ; B-D: 300 x ~ E: 260 x ; F-H: 600 x . |
