Fig. 7.

Recruitment of p300 to organizer gene promoters by Wnt and Nodal pathway effectors. (A)–(C) At the one-cell stage the animal pole was injected with Xnr1 (A), Sia (B) or Twn (C), either alone or together with full length E1A or E1AΔ2-36 as a negative control. Two-cell embryos were injected with the Gsc reporter (100 pg) and CMV-Renilla Luciferase (10 pg) plasmids. Animal explants prepared at the blastula stage were assayed for luciferase activity at the midgastrula stage. Values shown are normalized to Renilla luciferase activity, and represent fold activation of reporter activity in the absence of injected mRNAs. The mean and standard error for three independent experiments are presented. ^*Indicates p value <0.05 as compared to Xnr1, Sia or Twn activation of Gsc reporter. (D)–(F) Genomic regions recovered by ChIP for myc-p300 (4 ng plasmid injected) either alone or coexpressed with 150 pg GST-Sia or 150 pg GST-Twn or 50 pg Xnr1 were evaluated by QPCR for the (D) Gsc, (E) Cer, or (F) Chd promoters. The white bars represent QPCR for genomic Xmlc2 as a control. The mean fold enrichment (normalized to uninjected samples) and standard error for six independent experiments is presented.^*Indicates p<0.05 when compared to myc-p300 alone.