Q9HBU1

The BAR homeobox (Barx) family of proteins comprise Barx1 and Barx2. These proteins are regulators of place-dependent morphogenesis and play important roles in controlling the expression patterns of cell adhesion molecules. Barx1, a 226-amino acid nuclear protein, is expressed primarily in testis, heart, and craniofacial tissue. Barx1 is a homeodomain transcription factor important in odontogenesis, craniofacial development, and stomach organogenesis. Barx1 controls mesenchymal cell expression of two secreted Wnt antagonists, sFRP1 and sFRP2, proteins that are important in the development of the gastric endoderm which occurs before the epithelial differentiation. During early stages of molar development, Barx1 directs the undetermined ectomesenchymal cells in the proximal region of the jaws to follow the pathway of multicuspid tooth development. Fibroblast growth factor-8 (FGF8) stimulates Barx1 expression, while bone morphogenetic protein-4 (BMP4) inhibits Barx1 expression.