TRANSFORMATION OF TOOTH TYPE INDUCED BY INHIBITION OF BMP SIGNALING

Mammalian dentitions are highly patterned, with different types of tee th positioned in different regions of the jaws. BMP4 is an early oral epithelial protein signal that directs odontogenic gene expression in mesenchyme cells of the developing mandibular arch, BMP4 was shown to inhibit expression of the homeobox gene Barx-1 and to restrict express ion to the proximal, presumptive molar mesenchyme of mouse embryos at embryonic day 10, The inhibition of BMP signaling early in mandible de velopment by the action of exogenous Noggin protein resulted in ectopi c Barx-1 expression in the distal, presumptive incisor mesenchyme and a transformation of tooth identity from incisor to molar.