Transcriptional repressor involved in embryonic nervous system development. Plays a role in the induction and patterning of the anterior-posterior neural axis. Involved in the establishment of floor plate differentiation from neural plate cells during gastrulation. Binds the anf1 promoter sequence to restrict expression of anf1 to the anterior of the neural plate, thereby patterning the forebrain. Can bind to the HNF-3-alpha DNA target sequence. Cooperates with t/bra in a dose-dependent manner to specify dorsal mesoderm formation, including notochord. May be involved in the dorso-ventral patterning of the mesoderm. Binds to DNA via the target sequence 5'-[GA]TAAA[TC]A-3', with 5'-GTAAATA-3' being the preferred binding site (By similarity).