A-F) Expression of bmp-4 (A, B), chordin (C,D), and noggin (E,F) in late gastrula stage embryos is unaffected by VPA (B, D, F); orientation: posterior view, dorsal to the top. G-I) Quantitative RT-PCR of ectodermal explants harvested at tailbud stages (stage 28-31). G) Injection of bmp4 mRNA (2 ng) induced globin expression and VPA inhibited this effect. H) Injection gata1 mRNA (200pg) induced globin expression and VPA treatment inhibited this effect. I) Injection of bmp4 induced expression of runx1 and VPA blocked this effect. J) VPA upregulated endogenous expression of ncam in uninjected explants.