Project description:We show that loss of Arid1a impairs the differentiation-associated cell cycle arrest of tooth root progenitors through Hh signaling regulation, leading to shortened roots. Our data suggest that Plagl1, as a cofactor, endows Arid1a with its cell type/spatial functional specificity.
Project description:We show that loss of Arid1a impairs the differentiation-associated cell cycle arrest of tooth root progenitors through Hh signaling regulation, leading to shortened roots. Our data suggest that Plagl1, as a cofactor, endows Arid1a with its cell type/spatial functional specificity.
Project description:We show that loss of Arid1a impairs the differentiation-associated cell cycle arrest of tooth root progenitors through Hh signaling regulation, leading to shortened roots. Our data suggest that Plagl1, as a cofactor, endows Arid1a with its cell type/spatial functional specificity.
Project description:Chromatin remodelers often show broad expression patterns in multiple cell types yet can elicit cell-specific effects in development and diseases. Arid1a binds DNA and regulates gene expression during tissue development and homeostasis. However, it is unclear how Arid1a achieves its functional specificity in regulating progenitor cells. Using the tooth root as a model, we show that loss of Arid1a impairs the differentiation-associated cell cycle arrest of tooth root progenitors through Hedgehog (Hh) signaling regulation, leading to shortened roots. Our data suggest that Plagl1, as a co-factor, endows Arid1a with its cell-type/spatial functional specificity. Furthermore, we show that loss of Arid1a leads to increased expression of Arid1b, which is also indispensable for odontoblast differentiation but is not involved in regulation of Hh signaling. This study expands our knowledge of the intricate interactions among chromatin remodelers, transcription factors, and signaling molecules during progenitor cell fate determination and lineage commitment.
Project description:This study aimed to perform transcriptome profiling of Nfic-/- and corresponding control tooth germ at root initiation stage to identify differentially expressed for key regulators of root development. Coordination between the Hertwig’s Epithelial Root Sheath (HERS) and apical papilla (AP) is crucial for proper root development process. The Hedgehog (Hh) signaling pathway and Nfic are both involved in tooth root development.
Project description:Previous studies have suggested that Bmp4 is a key Msx1-dependent mesenchymal odontogenic signal for driving tooth morphogenesis through the bud-to-cap transition. Whereas the bud stage tooth developmental arrest in Msx1-/- mutant mice was accompanied by reduction in mesenchymal Bmp4 mRNA expression, we show that depleting functional Bmp4 mRNAs in the tooth mesenchyme, through neural crest-specific gene inactivation in Bmp4f/f;Wnt1Cre mice, caused mandibular molar developmental arrest at the bud stage but allowed maxillary molars and incisors to develop to mineralized teeth. We show that the Wnt inhibitors Dkk2 and Wif1 were much more abundantly expressed in the mandibular than maxillary molar mesenchyme in wildtype embryos and that Dkk2 expression was significantly unregulated in the tooth mesenchyme in Bmp4f/f;Wnt1Cre embryos. In addition, expression of Osr2, which encodes a zinc finger protein that antagonizes Msx1-mediated activation of odontogenic mesenchyme, is significantly upregulated in the molar mesenchyme in Bmp4f/f;Wnt1Cre embryos. Msx1 heterozygosity enhanced maxillary molar developmental defects whereas Osr2 heterozygosity rescued mandibular first molar morphogenesis in Bmp4f/f;Wnt1Cre mice. Moreover, in contrast to complete lack of supernumerary tooth initiation in Msx1-/-Osr2-/- mutant mice, Osr2-/-Bmp4f/f;Wnt1Cre compound mutant mice exhibit formation and subsequent arrest of supernumerary tooth germs that correlated with down regulation of Msx1 expression in the tooth mesenchyme. Taken together, our data indicate that, while reduction in mesenchymal Bmp4 expression alone could not account for the tooth bud arrest phenotype in Msx1-/- mutant mice, Bmp4 signaling synergizes with Msx1 and antagonizes Osr2 to activate mesenchymal odontogenic activity to drive tooth morphogenesis and sequential tooth formation. E13.5 mouse embryos tooth germs were microdissected by laser capture microdissection (LCM), and the mandibular molar and maxillary molar were separated. 3 pairs of control and mutant samples were pooled for the RNA extraction.