Potent dorsalizing factor. Has potent axis-forming activities including the ability to recruit neighboring cells into secondary axes. Regulates cell-cell interactions in the organizing centers of head, trunk and tail development. Interacts with twsg1 and/or bmp4. Interacts with olfml3/ont1. First expressed at stage 9.5 in the dorsal marginal zone. 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 prechordal plate (head mesoderm) and notochord during early neurulation (stage 13), transiently in the forebrain, tailbud hinge and posterior notochord in the early tailbud (stage 26), the chordoneural hinge in the late tailbud (stage 33) and finally the tip of the tail in the tadpole (stage 42). By activin in the presence of de novo protein synthesis, and by gsc and not2. Cleaved by bmp1; cleavage participates in dorsoventral patterning during early development. Cleavage by bmp1 is enhanced by the interaction with olfml3/ont1. Belongs to the chordin family.