title: Expression patterns of genes critical for BMP signaling pathway in developing human primary tooth germs.
abstract: The developing murine tooth has been used as an excellent model system to study the molecular mechanism of organ development and regeneration. While the expression patterns of numerous regulatory genes have been examined and their roles have begun to be revealed in the developing murine tooth, little is known about gene expression and function in human tooth development. In order to unveil the molecular mechanisms that regulate human tooth morphogenesis, we examined the expression patterns of the major BMP signaling pathway molecules in the developing human tooth germ at the cap and bell stages by in situ hybridization, immunohistochemistry, and real-time RT-PCR. Expression of BMP ligands and antagonist, including BMP2, BMP3, BMP4, BMP7, and NOOGGIN, exhibited uniform patterns in the tooth germs of incisor and molar at the cap and bell stages with stronger expression in the inner dental epithelium than that in the dental mesenchyme. Both type I and type II BMP receptors were present in widespread expression pattern in the whole-enamel organ and the dental mesenchyme with the strongest expression in inner dental epithelium at the cap and bell stages. SMAD4 and SMAD1/5/8 showed an expression pattern similar to that of BMP ligands with more intensive signals in the inner dental epithelium. Despite some unique and distinct patterns as compared to the mouse, the intensive expression of BMP signaling pathway molecules in the developing human tooth strongly suggests conserved functions of BMP signaling during human odontogenesis, such as in mediating tissue interactions and regulating differentiation and organization of odontogenic tissues. Our results provide an important set of documents for studying molecular regulatory mechanisms underlying tooth development and regeneration in humans.
authors.affiliation: Center for Biomedicine Research of South China, Fujian Key Laboratory of Developmental and Neuro Biology, College of Life Science, Fujian Normal University, Fuzhou, 350108, Fujian, People's Republic of China.
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Dong
authors.forename: Bin
authors.initials: B
authors.lastname: Shen
authors.forename: Ningsheng
authors.initials: N
authors.lastname: Ruan
authors.forename: Zhen
authors.initials: Z
authors.lastname: Guan
authors.forename: Yanding
authors.initials: Y
authors.lastname: Zhang
authors.forename: YiPing
authors.initials: Y
authors.lastname: Chen
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Hu
mesh_terms: D037881:Aborted Fetus; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000235:genetics* / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000235:genetics*; D014070:Tooth / Q000378:metabolism; D014083:Tooth Germ / Q000378:metabolism*
chemical_list: D019485:Bone Morphogenetic Proteins