Project description:Sequenced samples are cultured posterior parts of the first mouse molar tooth primordia. RNA sequencing was performed based on explants after 0, 16 or 24 hours of in vitro culture respectively, with aim to define candidate genes playing a role in the tooth germ development.
Project description:We identified the spatiotemporal pattern of cascade initiation of additional molars in miniature pig,where second molar (M2) initiated from the posterior-free end of the dental lamina over the first molar (M1) at E60 when M1 progressed to the late bell stage. Similarly, third molar (M3) budded off from the posterior-free end of the dental lamina over M2, which reached bell stage at PN20. However, the molecular mechanisms of the regulatory network during sequential formation of additional molars remain poorly characterized in diphyodont mammals. We performed microarrays on miniature pigs at three molar developmental stages to examine their differential gene expression profiles and potential regulatory networks during additional molar morphogenesis.
Project description:To identify genes heretofore undiscovered as critical players in the biogenesis of teeth, we have used microarray gene expression analysis of the developing mouse molar tooth (DMT) between 1 and 10 days postnatal to identify genes differentially expressed when compared to 16 control tissues (GEO accession # GSE1986). Of the top 100 genes exhibiting increased expression in the DMT, 29 were found to have been previously associated with tooth development. Differential expression of the remaining 71 genes not previously associated with tooth development was confirmed by qRT-PCR analysis. Further analysis of seven of the latter genes by mRNA in situ hybridization found that five were specific to the developing tooth in the craniofacial region (Rspo4, Papln, Amtn, Gja1, Maf). Of the remaining two, one was found to be more widely expressed (Sp7) and the other was found to be specific to the nasal serous gland, which is close to, but distinct from, the developing tooth (Vrm). Experiment Overall Design: mRNA from molar teeth extracted from Swiss Webster mouse pups between 1 and 10 days post-natal was pooled, labeled, and hybridized in quadruplicate to Affymetrix Mouse Genome Expression 430 2.0 microarrays. This data was compared to that of 16 control tissues (GEO accession # GSE1986) to identify genes differentially expressed in the DMT mRNA.
Project description:The molecular mechanisms of the regulatory network of mRNAs and long non-coding RNAs during sequential formation of additional molars remain poorly characterized in diphyodont mammals. The diphyodont miniature pig has proved to be a valuable model for studying human molar morphogenesis. Here, we performed RNA-seq on miniature pigs at three molar developmental stages to examine their differential gene expression profiles and potential regulatory networks during additional molar morphogenesis. Many new unannotated genes plus putative long non-coding RNAs were identified. Our data provide fundamental knowledge and a basis for understanding the molecular mechanisms governing cascade initiation of additional molars.
Project description:When evolution leads to differences in body size, organs generally scale along. A well-known example of the tight relationship between organ and body size is the scaling of mammalian molar teeth. To investigate how teeth scale during development and evolution, we compared mouse and rat molar development from initiation through final size. Whereas the linear dimensions of the rat first lower molar are twice that of the mouse molar, their shapes are largely the same. We found that scaling of the molars starts early, and that the rat molar is patterned equally as fast but in a larger size than the mouse molar. Using transcriptomics, we discovered that a known regulator of body size, insulin-like growth factor 1 (Igf1), is more highly expressed in the rat molars compared to the mouse molars. Ex vivo and in vivo mouse models demonstrated that modulation of the IGF pathway reproduces several aspects of the observed scaling process. Furthermore, analysis of IGF1-treated mouse molars and computational modeling indicate that IGF signalling scales teeth by simultaneously inhibiting the cusp patterning programme and by enhancing growth, thereby providing a relatively simple mechanism for scaling teeth during development and evolution. Finally, comparative data from shrews to elephants suggest that this scaling of patterning mechanism regulates the minimum tooth size possible, as well as the patterning potential of large teeth.