Fig. 5. Misexpression of SpOtx and SpGsc drive ectoderm toward aboral and oral fate, respectively. Confocal images of 3-day-old embryos double-stained with anti-EctoV and anti-Spec1 that (top panels) identify oral (red) and aboral (green) ectodermal territories in normal embryos at this stage. Sibling embryos were injected with mRNAs encoding either SpGsc (middle panels) or a fusion protein consisting of the SpGsc DNA-binding domain linked to the VP16 transcriptional activation domain (bottom panels). Separate Spec1 (left panels) and EctoV (center panels) signals are merged in the right panels. Misexpression of SpGsc promotes expression of the oral ectoderm marker in all ectodermal cells while misexpression of the VP16 fusion protein has the reciprocal effect, driving these cells to express predominantly the aboral ectoderm marker. All these confocal images were obtained at the same photomultiplier sensitivity. Scale bar: 10 µm.