Fig. 2. GATAa is necessary and sufficient for FGF-independent animal-wide activity. (A) Deletion constructs of the conserved pfog region identify two GATA sites required for lacZ reporter expression. The level of lacZ reporter activity in animal blastomeres at the 110-cell stage is quantified as in Fig. 1; n80 for each construct. The pfog-m314 construct has a point mutation in each of the two GATA binding site (red crosses). (B) Animal view of 110-cell stage embryos co-injected with pfog-314 and either control-MO or GATAa-MO, stained with X-Gal. Numbers indicate the proportion of positive embryos. (C) lacZ reporter activity at the 110-cell stage in embryos co-injected with G12 and either water, GATAa-MO, GATAa-MO with GATAa mRNA or GATAa-MO with GATAb mRNA. Numbers indicate ß-gal-positive embryos. (D) lacZ reporter activity at the 110-cell stage in embryos electroporated with G12 with or without U0126 treatment. The quantification of expression within the animal region is sorted by cell lineage derivatives of the 32-cell stage (bottom right corner). A representative untreated embryo is shown (110-cell stage, upper right corner, animal view, anterior is up).