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. 1998 Aug 4;95(16):9337–9342. doi: 10.1073/pnas.95.16.9337

Figure 1.

Figure 1

Inhibitory interaction between follistatin and BMPs. (A) Phenotypes of Xenopus embryos dorsally coinjected with BMP mRNA and follistatin mRNA. BMP-4 mRNA (200 pg), either alone (b) or with 100 pg of follistatin mRNA (d), and BMP-7 mRNA (500 pg), either alone (c) or with 50 pg of follistatin mRNA (e), were injected into the equatorial region of the two dorsal blastomeres at the four-cell stage as described (28). In contrast, equatorial regions of two ventral blastomeres at the four-cell stage were injected with follistatin mRNA (60 pg), either alone (f), with 500 pg of BMP-4 mRNA (g), or with 2 ng of BMP-7 mRNA (h). Embryos were evaluated and photos were taken at the tadpole stage. (a) Uninjected embryo. (B) Expression of molecular markers in dorsal and ventral marginal explants. Embryos were either uninjected (lane 1, 6, 7, 11, and 12) or injected with the mRNAs indicated on the top of each lane into the equatorial region of two dorsal (lane 2–5) or ventral blastomeres (lane 8–10) at the four-cell stage. The amounts of mRNA for dorsal injection were 200 pg of BMP-4 (lane 2), 200 pg of BMP-4 plus 200 pg of follistatin (lane 3), 500 pg of BMP-7 (lane 4), and 500 pg of BMP-7 plus 50 pg of follistatin (lane 5). For ventral injection, 60 pg of follistatin mRNA, 500 pg of BMP-4 mRNA, and 2 ng of BMP-7 mRNA were used. Lane 12 shows the expression of markers in whole embryos and lane 6 and 11 show the control reactions with no RT step. Dorsal or ventral marginal zones were excised and explanted at the early gastrula stage and incubated until sibling embryos reached stages 11 and 36.