FIG. 7. Suppression of FGF signaling in ectoderm cells by a truncated XFGFR-4a (DXFGFR-4a). (A) Effects of overexpression of DXFGFR-4a in ectoderm cells on neural induction and epidermal inhibition by bFGF. DXFGFR-4a mRNA was injected into four animal blastomeres at the eight-cell stage (150 or 300 pg/blastomere). The injected or uninjected embryos were incubated until stage 10 when ectoderm cells were isolated and cultured in the presence of a low (0.25 ng/ml) or high (5.0 ng/ml) dose of bFGF in microculture wells. The transcription levels of two anterior neural markers, XeNK-2 and En-2, and an epidermal marker, Keratin, in these cultures were analyzed by quantitative RT-PCR assay as described (Kengaku and Okamoto, 1995). Autoradiographs are shown of RT-PCR products of the marker transcripts coamplified with EF1a transcript (an internal standard) in uninjected ectoderm cells (left panels) and injected ectoderm cells (middle and right panels). (B) Quantitative assessment of effects of injected DXFGFR-4a mRNA. Each RT-PCR product shown in (A) was quantified as in Fig. 5B. Values were normalized to EF1a expression as in Fig. 6B and presented as percentages of the maximum values of the ratio in each histogram for XeNK-2 (top), En-2 (middle), and Keratin (bottom).
Image published in: Hongo I et al. (1999)
Copyright © 1999. Image reproduced with permission of the Publisher, Elsevier B. V.
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