May function as an inhibitor of bone morphogenetic proteins (BMP) signaling during later stages of development including late phases of dorsoventral patterning, to refine the early pattern set up by the interaction of chordino and BMP2/4. Not involved in organizer function or early phases of dorsoventral pattern formation. Homodimer; disulfide-linked. Expression is limited to late stages of embryogenesis. First detected at 48 hours of development and restricted to regions of ongoing chondrogenesis. Expression is observed in the ethmoid plate and the trabeculae cranii of the neurocranium as well as in some presumptive cartilage cells of the pharyngeal arches. Expression is furthermore observed in the forming cartilage of the pectoral fins. At 72 hours of development, accumulates in the ceratobranchial and basibranchial parts of the gill arches. Belongs to the noggin family.