cebpa induces blood markers in animal caps. (A) Injection of cebpa mRNA in the animal pole at one-cell stage induced precocious expression of all blood markers, with the exception of globin and rag1, in X laevis animal caps. eGFP mRNA was injected as control. Animal caps were excised at stage 8 and cultured in 0.2% bovine serum albumin, 75% NAM, until their sibling whole embryos reached stage 11 or 15. At stage 11, spib (i), lurp (ii), and fli1 (v) were strongly up-regulated, whereas mpo (iii), mmp7 (iv), and scl (vi) were strongly up-regulated at stage 15. In contrast, globin (x), rag1 (xi), and several nonhematopoietic markers, including gsc (vii), xbra (viii), and keratin (ix), were not induced. Ø: undetectable expression level. (B) The early induced genes, spib and lurp, were activated in the presence of CHX (i-ii), while the late induced genes mpo and mmp7 were not (iii-iv). Expression levels were normalized relative to rpl8. Error bars represent SEM of 3 independent experiments. Statistical ANOVA was done using the SPSS software package. Conditions that showed a significant difference in expression level comparing the cebpa-overexpressing animal caps with and without CHX are labeled *P < .01; **P < .001.