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. Binds to DNA via the target sequence 5'-[GA]TAAA[TC]A-3', with 5'-GTAAATA-3' being the preferred binding site. During stages 8.5 to 10, expressed in the part of the dorsal mesoderm invaginating the dorsal blastopore lip (Spemann organizer), as a direct response to dorsal mesodermal induction. At stage 12 (mid-gastrulation), restricted to the dorsal midline in the deeper layers of mesodermal cells. Continuously present in the posterior portion of invaginated mesoderm and expressed within the notochord. Also present in the midline of the neural plate during gastrulation, but absent from the notoplate in exogastrula embryos. Expression in the notochord continues in neurula-stage embryos and at stage 20 in addition to the notochord, expression is seen in the pharyngeal endoderm. First expressed at the late blastula stage (stage 9). Most abundant during gastrulation, with levels peaking in mid-gastrula embryos (stage 12) before declining rapidly at the end of neurulation and becoming barely detectable in the late tailbud-early tadpole stage. By activin, derriere and not2.