Fig. 3. Xbra, VegT and Eomesodermin specificity resides mainly in the T box. (A) Chimeric proteins comprising the T boxes of Xbra, VegT and Eomesodermin fused to the GAL4 DNA-binding domain and the VP16 activation domain. Proteins were expressed in early Xenopus embryos and their abilities to activate gene expression were assessed by RNAase protection. (B) Xbra and Xbra-VP16. (C) VegT and VegT-VP16. (D) Eomesodermin and Eomesodermin-VP16. Note that the inductive abilities of the chimeric constructs resemble those of the parent molecule.