Involved in the transcriptional regulation of genes required for mesoderm formation and differentiation. Binds to a palindromic site (called T site) and activates gene transcription when bound to such a site. Monomer. Binds DNA as a monomer. First expressed in the posterior epiblast of stage XIII blastoderm, then in the elongating primitive streak, early migrating mesoderm, Hensen node and in the notochord. In later stages, found in tail bud and entire notochord up to stage 26-28. By FGF-4 and activin.