Transcriptional repressor (By similarity). Plays a fundamental role in notochord formation, acting within the mesodermal region. Acts downstream of gsc and upstream of chrd and foxa4-A/pintallavis. Localized to the dorsal lip of the blastopore (Spemann organizer) during early gastrulation, after which expression continues in tissues derived from the organizer. Expressed in the notochord during mid-gastrulation, the chordoneural hinge, notochord and ventral spinal cord of the tailbud at stage 22, and finally the tip of the tail in the tadpole (stage 35).