GATA-1 is expressed in the early blood island regions of VAD embryos.

Normal (A, C) or VAD (B, D) embryos were analyzed at stage 8 (A, B) or stage 11 (C, D) as in Figure 3, except that a probe was used to detect GATA-1 transcripts. In contrast to GATA-2, the pattern at stage 8 is similar comparing normal and VAD embryos, though GATA-1 expression becomes restricted to lateral regions by stage 11. Arrows indicate GATA-1–expressing blood islands. Original magnification × 32.