Participates in the Wnt signaling pathway. Probably binds to DNA and acts as a repressor in the absence of ctnnb1, and possibly as an activator in its presence. Required early in development for dorsal specific gene activation and during gastrulation for repression of dorsal-specific genes in the marginal zone. Required for head formation and forebrain specification. Regulates anterior-posterior patterning in the neuroectoderm by repressing posterior neural fates. Interacts with tle3a/gro2. Expressed maternally and throughout embryogenesis. Expressed in the dorsal mesoderm at 6 hours post fertilization (6 hpf), and this expression is maintained in the axial mesoderm during gastrulation and early somitogenesis. Strongly expressed in the prospective neuroectoderm at 8 hpf. Expression persists in the neuroectoderm and increases in the tail bud at the end of gastrulation, at 10 hpf. Enriched in the prechordal mesoderm and developing notochord and in ventromedial regions of the brain and neural tube during the early somite stages. Expression remains elevated within the tail bud, forebrain, the midbrain-hindbrain boundary and in the developing otic vesicles as somitogenesis progresses. By ctnnb1. Belongs to the TCF/LEF family.