Xenbase Image ID: 75411

Fig. 4. Nodal signaling, but not FGF signaling, is necessary for expression of zygotic VegT. (A,B) CerS inhibits zVegT expression in X. laevis embryos. WISH of the zVegT gene was performed on CerS- injected or uninjected embryos. 300 pg of CerS mRNA was injected into the marginal zone of one blastomere at the two-cell stage, and embryos were harvested at stage 11. Panels at the left and right for the CerS- injected embryo show the vegetal view with the dorsal side up and lateral view, respectively. (C) Expression of the zVegT gene is inhibited by coinjection of CerS mRNA in animal caps. CerS (600 pg) was coinjected with zVegT, Eomes, Tbx6, or Xbra (1 ng) into the animal pole of both blastomeres at the two-cell stage. Animal cap cells were explanted at stage 9 and then cultured until stage 11 for RT-PCR. Injected mRNAs were not detected by these experiments. (D-K) FGF signaling is not required for zVegT gene expression. The overexpression of XFD inhibited the expression of Xbra (H,I) and Tbx6 (J,K), but not the expression of zygotic VegT (D,E) and Eomes (F,G) in X. laevis embryos. Embryos were injected with 1 ng of XFD mRNA into the dorsal marginal zone of two blastomeres at the four-cell stage, and were fixed at stage 11 for WISH. Vegetal views are shown with dorsal side up. (L) Expression of zVegT and FGFs is induced dose-depen- dently by Activin in animal cap cells. The animal caps dissected at stage 9 were treated with 1, 10, or 100 ng/ml Activin, and harvested at stage 11 for RT-PCR analysis. (M) Expression of zVegT is induced by Activin independent of FGF signaling. The animal caps dissected at stage 9 were treated with or without Activin (10 ng/ml) and SU5402 (80 μM), and were harvested at stage 11 for RT-PCR analysis. The induction of expression of zVegT and Eomes by Activin was not affected by inhibition of FGF signaling. The expression of Xbra and Tbx6 was downregu- lated by SU5402 in animal cap cells. Image published in: Fukuda M et al. (2010) Copyright © 2010. Reproduced with permission of the Publisher, University of the Basque Country Press. Gene Synonyms Species Stage(s) Tissue vegt.L antipodean, brat, tVegT, vegt-a, vegt-b, xombi X. laevis Throughout NF stage 11 ventral marginal zone ventro-lateral marginal zone dorso-lateral marginal zone blastopore lip eomes.L eomesodermin, tbr2, xeomes X. laevis Throughout NF stage 11 blastopore lip tbx6.L XTbx6 X. laevis Throughout NF stage 11 blastopore tbxt.S bra, brachyury, ntl, t, t-a, t-b, X-bra, Xbra, Xbrachyury X. laevis Throughout NF stage 11 blastopore lip Image source: Published Larger Image Printer Friendly View

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