Figure 2

Regulation of Lef/Tcf expression by Lef/Tcfs in neuralized animal caps. (A) RT-PCR on sibling embryos (emb), animal cap explants of naive animal caps (cont), neuralized animal caps (tBr) and neuralized animal caps coinjected with truncated BMP receptor (tBr) and the indicated morpholino (Tcf3Mo: XTcf-3 specific antisense morpholino oligonucleotide, Tcf4Mo: XTcf-4 specific antisense morpholino oligonucleotide) revealed that the expression of XLef-1 and XTcf-1 (but not of XTcf-3 and XTcf-4) depends on the presence of XTcf-3 and XTcf-4. NCAM is the amplification of the pan-neural marker gene neural cell adhesion molecule, H4 the amplification of the house keeping gene histone 4, -RT the control amplification without reverse transcription. (B) Co-injection of 500 pg Lef/Tcf mRNA together with 100 pg tBr indicated complex cross-regulation of Lef/Tcf transcription factors in neuralized animal caps. NCAM is the amplification of the pan-neural marker gene neural cell adhesion molecule, H4 the amplification of the house keeping gene histone 4, -RT the control amplification without reverse transcription. (C) The pattern of XTcf-4 isoforms remained unchanged following XTcf-3 and XTcf-4 knockdown. Amplicons were digested with isoform-specific restriction enzymes (1: XbaI, 2: RsaI, 3: XbaI + RsaI) and analysed according to [27].