Transcriptional activator. First detected at the tail bud stage in the forebrain. At the 3-somite stage, also expressed weakly in the hindbrain. At the 12-somite stage, strongly expressed in the forebrain and weakly expressed throughout the central nervous system. At the 21-somite stage, also expressed in the lens. Expressed zygotically. First detected at the tail bud stage and continues to be expressed for at least the first 48 hours of development. The 9aaTAD motif is a transactivation domain present in a large number of yeast and animal transcription factors.