Overexpression Of Bmp4Affects Tooth Development

The development of mammalian tooth is controlled by sequential and reciprocal signaling between the epithelium and mesenchyme.Among many regulators, BMP signaling plays a pivotal role in mediating the epithelial-mesenchymal interaction during the development of tooth. BMP signaling pathways is a complicated network of various factors intracellular and extracellular. The interaction coefficients of these factors is critical for maintaining the normal development of tooth.Embryos with overexpression of Bmp4in mesenchyme were obtained by crossing pMes-Bmp4mice with Wnt1-Cre mice.BMP signaling were risen in mesenchyme of Wnt1-Cre;pMes-Bmp4mice.It result in a smaller body size, incomplete fusion of jaws, coloboma and only one molar development into both sides. In addition,The expression og Msx1and Pax9which could regulate the expression of Bmp4were risen.We could draw a conclusion that BMP homeostasis is required for maintaining the normal development of tooth.Embryos with overexpression of Bmp4in dental epithelium were obtained by crossing pMes-Bmp4mice with K14-Cre mice.BMP signaling were risen in dental epithelium of K14-Cre; pMes-Bmp4mice.In this study,we found tooth development was normal in K14-Cre; pMes-Bmp4mice.Despite ectopic expression of Bmp4in dental epithelium,the expression of other genes include Bmp2、Bmp7、Noggin、Chordin and Gremlin was normal. According to our calculation, different tooth types or different tissue show different toleration for BMP homeostasis in tooth development.Our results will have great implication in mechanism of BMP homeostasis and tooth development,well as providing a theoretical basis for researching the development of other organa.