Fig. 7. Testing novel modes of endoderm gene regulation predicted by array analysis. (A-H) At the two-cell stage, embryos were injected with either Cerb-S RNA to inhibit nodal signaling (1 ng), antisense morpholino oligos to Sox171+2+ß (Sox17-MO; 20 ng each) or Mixer antisense morpholino oligos (40 ng/embryos). Some Cerb-S-injected embryos were subsequently injected with XtSox17ß RNA (10-100 pg), Mixer RNA (50-500 pg) or Gata6 RNA (50-100 pg) to rescue target gene expression. A range of rescue RNA doses was used and the lowest does that gave a reproducible rescue is shown. At stage 11, RNA from the resulting embryos was assayed by real-time RT-PCR for the expression of the indicated transcripts. Relative expression normalized to ODC is shown and the expression level in control gastrula was set to 1.0. Each experiment was repeated at least twice and a representative experiment is shown. Potential regulatory pathways are shown for each class of regulation (right).