Dorsalizing factor. Key developmental protein that dorsalizes early vertebrate embryonic tissues by binding to ventralizing TGF-beta family bone morphogenetic proteins (BMPs) and sequestering them in latent complexes (By similarity). Interacts with TWSG1 and/or BMP4. Cleaved by tolloid proteases; cleavage participates in dorsoventral patterning during early development. Belongs to the chordin family.