Chordin

CHRD domain
Identifiers
Symbol	CHRD
Pfam	PF07452
InterPro	IPR010895
SMART	SM00754
PROSITE	PS50933
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

chordin
Identifiers
Symbol	CHRD
Entrez	8646
HUGO	1949
OMIM	603475
RefSeq	NM_003741
UniProt	Q9H2X0
Other data
Locus	Chr. 3 q27

Chordin is a bone morphogenetic protein antagonist composed of four small cysteine-rich domains, whose function is not known. Chordin was originally identified in Xenopus laevis in the laboratory of Edward M. De Robertis as a key developmental protein that dorsalizes early vertebrate embryonic tissues. The polypeptide is 941 amino acids long and 120 kDa large and it dorsalizes the developing embryo by binding ventralizing TGFβ proteins such as bone morphogenetic proteins. It may also play a role in organogenesis. There are five named isoforms of this protein that are produced by alternative splicing.

In mice, Chordin is expressed in the node but not in the anterior visceral endoderm. It has been found to be required for forebrain development. In developing mice that are deficient in both chordin and noggin, the head is nearly absent. This is significant because when only noggin is deficient there are mild defects but the head still forms.

In humans, the chordin peptide is encoded by the CHRD gene.

Chordin is also involved in avian gastrulation. It is expressed in the anterior cells of Koller's sickle, which form the anterior cells of the primitive streak, a key structure through which gastrulation occurs.