Fig. 3

XFD blocks neural induction in MZoep mutants and wild-type embryos. Analysis of the expression patterns of ectodermal markers in control and XFD-injected MZoep mutant embryos. Lateral views of 24-h live control-injected wild type (A) and MZoep mutant (C) embryos and XFD-injected wild type (B) and MZoep (D) embryos. XFD overexpression results in posterior defects in wild-type embryos but anterior neural deficits are apparent in XFD-injected MZoep mutant embryos. Whole mount RNA in situ hybridization anterior neural and ectodermal markers in MZoep and wild-type control (E, G, I, K, M, and O) and XFD (F, H, J, L, N, and P) injected MZoep mutant embryos and wild-type embryos at mid-gastrula (70% epiboly). The expression domains of the anterior neural markers otx2 (E, F, G, and H) and opl (I, J, K, and L) are shifted toward the margin and dramatically reduced in XFD-injected embryos. The expression domains of gata2 (M, N, O, and P) in the ventral ectoderm in XFD-treated embryos are expanded compared to control-injected embryos. For all microinjection experiments, 125 pg of XFD mRNA was injected. The consequence of XFD treatment on transcript levels of markers of neural tissue and presumptive epidermis in MZoep mutants and wild-type embryos was monitored by real-time PCR (Q and R). The levels of neural markers otx2 and hoxb1b are decreased in embryos microinjected with 125 pg XFD mRNA, while the levels of presumptive epidermal markers gata2 and gata3 are increased. The fold change (y-axis) of these markers is set relative to control (GFP)-injected embryos. Embryos were collected at mid-gastrulation (70% epiboly).