July 1, 1998;
Xenopus eomesodermin is expressed in neural differentiation.
Our initial description of the Xenopus gene Eomesodermin
) indicated that it is expressed largely if not entirely in mesodermal cells of gastrula stage
embryos. A more detailed examination, described here, shows that it continues to be expressed in the most anterior
stages. However, during tail
-bud stages, Eomes
expression is re-born in the most anterior
part of the brain
, becoming strongly transcribed in the olfactory region
of the telencephalon
. This later Eomes
expression marks a very localized region of the forebrain
distinct from that of Otx-2
to that of En-1
and overlapping that of Sox-3.
[+] show captions
Fig. 2. Eomes and other gene expressions in tailbud embryos. (A) Cleared whole-mount in situ hybridization, stage 28; (G), whole-mount stained for Eomes; (H), horizontal section (in plane of line) through whole-mounts, stage 28; (I) vertical section, 50 mm to one side of the midline, in situ hybridized to Eomes mRNA, stage 23. Gene probes shown above and below plates. En, engrailed-1; N-tub, N-tubulin; st, stage
Fig. 3. Eomes expression, by in situ hybridization to a dissected brain from a stage 51 tadpole, is seen most strongly in the olfactory region of the anterior forebrain. (A) dissected brain; (B) ventral and dorsal view of telencephalon, dorsal view of hindbrain; (C) vertical section to one side of midline of Eomes- stained brain; (D) cresyl violet stain of section shown in (C). Abbreviations: aop, area olfactoria primitiva (arrows); e, epiphysis; c, Cb cerebellum; VA, ventral anterior; DA, dorsal anterior. Surface pigment cells appear as irregular black dots; Eomes staining is purple.