March 1, 2000;
Differential expression of the Groucho-related genes 4 and 5 during early development of Xenopus laevis.
Recently, we demonstrated that the Xenopus Wnt effector XTcf-3 interacts with Groucho-related transcriptional repressors (Roose et al., 1998. Nature 395, 608-612). A long form of the Groucho-related genes, XGrg-4, was shown to repress axis formation in the Xenopus embryo
, whereas a short form, XGrg-5, acted as a potentiator. In this study, the temporal and spatial expression of XGrg-4 and XGrg-5 is described in Xenopus laevis embryos. Both genes are maternally expressed. In the gastrula
, transcripts of both genes are present in the animal as well as the vegetal region. At later stages, XGrg-4 and XGrg-5 show specific patterns of expression in the central nervous system (CNS
), cranial ganglia
, otic vesicles, stomodeal-hypophyseal anlage, cement gland, head mesenchyme
, branchial arches, neural crest and derivatives, somites
, pronephric duct
. Differences in the expression of XGrg-4 and XGrg-5 were found in the CNS
, cranial ganglia
, olfactory placodes, stomodeal-pharyngeal anlage, cement gland, head mesenchyme
[+] show captions
Fig. 2. Whole mount in situ hybridization of gastrula stage embryos with antisense XGrg-4 and XGrg-5 probes. Dorsal views of stage 12 embryos (A, B). XGrg-5 expression along the midline is indicated by arrows (B).
Fig. 3. XGrg-4 and XGrg-5 expression in neurula stages. (A,B,D,E,F) Antero-dorsal views. (C) Sagittal section of a stage 16 embryo. (F) XEn-1 (Eizema et al., 1994) marks the mid-hindbrain border region. cg, cement gland, (1) stomato-hypophyseal anlage, (2) anterior neural plate, (3) prospective pros-mesencephalic boundary, (4) rim along the neural groove, (5) prospective anterior rhombencephalon.
Fig. 4. Expression of XGrg-4 in the ectoderm. Speckled expression of XGrg-4 in the ectoderm in stage 25 (B) and transverse section of a stage 22 embryo (A).
Fig. 5. Localization of XGrg-4 and XGrg-5 transcripts in early tailbud stage (22). (A–C) High XGrg-4 expression at the pros-mesencephalic boundary (1), at the mes-rhombencephalic boundary (2) and in the rhombencephalon (3). (D–F) High XGrg-5 expression in the prosencephalon (1), in the anterior rhombencephalon (2) and in the posterior rhombencephalon (3). Arrows in A and D: somites. Asterisks in C and F: mesenchyme between the prospective olfactory placodes. ba, branchial arches; opv, optic vesicle; ov, otic vesicle; p, pronephros; pd, pronephric duct; sha, stomodeal-hypophyseal anlage. Embryos are viewed from lateral (A,D), dorsal (B,E) or anterior (C,F).
Fig. 6. Localization of XGrg-4 and XGrg-5 expression at tailbud stage 35. (A,B) XGrg-4. (C,D) XGrg-5. (1) Pros-mesencephalic boundary, (2) mes-rhombencephalic boundary. V-X: cephalic ganglia V-X. Embryos are viewed from lateral (A,C) or anterior (B,D).