Transcriptional activator. Expressed both maternally and zygotically. Maternal expression is weak and zygotic expression is strong by the 30% epiboly stage. At the gastrula stage, expressed in all prospective neural tissue with the exception of a band of cells in the prospective midbrain and hindbrain. At the tail bud to 3-somite stage, expressed in distinct regions of the future brain, the anterior margin of the neural plate and the primordia of the epibranchial placodes. At the 12-somite stage, broad expression in the central nervous system (CNS), with weakest expression at the forebrain-midbrain and midbrain-hindbrain boundaries and in the posterior CNS. At the 21- to 25-somite stage, broad expression in the CNS and the lens. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors.