Project description:Purpose: the goals of this study are to explore the effect of loss of Ptip in Sp7 positive dental progenitor cells on CD45- Ter119- Tie2- dental progenitor cells Methods: CD45- Ter119- Tie2- dental progenitor cells were sorted by FACs in lower incisors from Ptipf/f and Ptipf/f;Sp7-cre mice and performed RNAseq Our finding reveals that Ptip as crucial regulator in tooth homeostasis, functioning to safeguard the Sp7+ progenitor cells epigenome from a breach in lineage confinement that triggers irreversible tooth defects. Conclusions: loss of Ptip unregulate dental development and active Wnt signal pathway
Project description:PPARg and C/EBPa cooperate to control preadipocyte differentiation (adipogenesis). However, the factors that regulate PPARg and C/EBPa expression during adipogenesis remain largely unclear. Here we show PTIP, a protein that associates with histone H3K4 methyltransferases, regulates PPARg and C/EBPa expression in mouse embryonic fibroblasts (MEFs) and during preadipocyte differentiation. PTIP deletion in MEFs leads to marked decreases of PPARg expression and PPARg-stimulated C/EBPα expression. Further, PTIP is essential for induction of PPARg and C/EBPa expression during preadipocyte differentiation. Deletion of PTIP impairs the enrichment of H3K4 trimethylation and RNA polymerase II on PPARg and C/EBPa promoters. Accordingly, PTIP-/- MEFs and preadipocytes all show striking defects in adipogenesis. Furthermore, rescue of the adipogenesis defect in PTIP-/- MEFs requires co-expression of PPARg and C/EBPa. Finally, deletion of PTIP in brown adipose tissue significantly reduces tissue weight in mice. Thus, by regulating PPARg and C/EBPa expression, PTIP plays a critical role in adipogenesis. To identify PTIP-regulated genes, immortalized PTIP conditional knockout PTIPflox/flox MEFs were infected with retroviruses expressing either Cre recombinase or vector alone. We prepared duplicated RNAs from either vector or Cre infected cells (PTIP+/+ or PTIP-/-) for 4 affymetrix microarrays.
Project description:PPARg and C/EBPa cooperate to control preadipocyte differentiation (adipogenesis). However, the factors that regulate PPARg and C/EBPa expression during adipogenesis remain largely unclear. Here we show PTIP, a protein that associates with histone H3K4 methyltransferases, regulates PPARg and C/EBPa expression in mouse embryonic fibroblasts (MEFs) and during preadipocyte differentiation. PTIP deletion in MEFs leads to marked decreases of PPARg expression and PPARg-stimulated C/EBPα expression. Further, PTIP is essential for induction of PPARg and C/EBPa expression during preadipocyte differentiation. Deletion of PTIP impairs the enrichment of H3K4 trimethylation and RNA polymerase II on PPARg and C/EBPa promoters. Accordingly, PTIP-/- MEFs and preadipocytes all show striking defects in adipogenesis. Furthermore, rescue of the adipogenesis defect in PTIP-/- MEFs requires co-expression of PPARg and C/EBPa. Finally, deletion of PTIP in brown adipose tissue significantly reduces tissue weight in mice. Thus, by regulating PPARg and C/EBPa expression, PTIP plays a critical role in adipogenesis.
Project description:During Drosophila development, Polycomb-group and Trithorax-group proteins function to ensure correct maintenance of transcription patterns by epigenetically repressing or activating target gene expression. To get a deep insight into the PcG and trxG pathways, we investigated a BRCT domain-containing protein called PTIP, which was generally identified as a transcriptional coactivator and belongs to the TRR complex. At the genome scale, we sorted given PTIP binding peaks into two groups: PTIP/TRR-cobound and PTIP/PC-cobound peaks. In particular, we found that PTIP mediates the molecular switch between H3K4me3/H3K27ac and H3K27me3 histone modifications at TRR or PC occupied regions. Thus, we suggest that PTIP is a mediator rather than a dedicated co-activator along PcG and trxG pathways. Our hypothesis is further supported by the genetic assay: PTIP interacts genetically with either PcG or TrxG in a dosage-dependent manner, suggesting that PTIP functions as a co-factor of PcG/TrxG proteins. In addition, in accordance with the analysis of ChIP-seq, these genetic interactions correlate with modified ectopic HOX protein levels in imaginal discs, which reveals an essential role for PTIP in PcG-mediated Hox gene repression. Hence, we reveal a novel role for PTIP in the epigenetic regulation of gene expression along PcG and trxG pathways.
Project description:We used single-cell RNA sequencing (scRNA-seq) to profile Wnt signaling genes in maxillary and mandibular tooth organs from E15.5 and P1 stages
Project description:Drosophila Kc167 cells were used to test the function of PTIP in regulating gene expression before and after loss of polycomb function. Four condtions were tested using dsRNA knockdowns (RNAi) Experiment Overall Design: Kc167 cells alone, Kc cells with loss of PTIP, cells with loss of polycomb and polyhomeotic, and cells with loss of PTIP, polycomb, and polyhomeotic. Performed in triplicate.
Project description:Odontomas are classified as odontogenic benign tumors, which show disorganized dental mineralized hard tissue formation in the jaw, but mechanisms in the induction of odontomas remain to be clarified. Odontomas are also thought to be developmental anomalies of tooth germ, which frequently occur in patients with familial adenomatous polyposis (FAP) involving activation of Wnt/b-catenin signaling. However, the roles of Wnt/b-catenin signaling in odontomas or odontogenic cells remain to be clarified. The current study was conducted to investigate the expression of b-catenin in odontomas and the function of Wnt/b-catenin signaling in odontogenic epithelial cells and tooth germ development. b-catenin frequently accumulated in the nucleus and/or cellular cytoplasm of remaining odontogenic epithelial cells in human odontoma specimens, immunohistochemically. Activation of Wnt/b-catenin signaling inhibited odontogenic epithelial cell proliferation and mouse tooth germ development, while inducing epithelial bud formation in the novel developed epithelial tooth bud culture system derived from mouse tooth germ. We identified Semaphorin 3A (Sema3A) as a downstream molecule of Wnt/b-catenin signaling using DNA microarray analysis and showed that Wnt/b-catenin signaling-dependent reduction of Sema3A expression resulted in suppression of odontogenic epithelial cell proliferation. Novel developed epithelial tooth bud culture system revealed that Sema3A expression is required in epithelial budding morphogenesis. These results suggest that Wnt/b-catenin signaling negatively regulates odontogenic epithelial cell proliferation and tooth germ development through decreased-Sema3A expression, and aberrant activation of Wnt/b-catenin signaling may be associated with the formation of odontomas.
Project description:Methylation of histone H3 lysine 4 (H3K4me) at actively expressed, cell type-specific genes is established during development by the Trithorax group of epigenetic regulators. In mammals, the Trithorax family includes KMT2A-D (MLL1-4), a family of SET domain proteins that function in large complexes to impart mono-, di-, and trimethylation at H3K4. Individual KMT2s and their co-factors are essential for embryonic development and the establishment of correct gene expression patterns, presumably by demarcating the active and accessible regions of the genome in a cell specific and heritable manner. Despite the importance of H3K4me marks in development, little is known about the importance of histone methylation in maintaining gene expression patterns in fully differentiated and non-dividing cell types. In this report, we utilized an inducible cardiac-specific Cre driver to delete the PTIP protein, a key component of a H3K4me complex, and ask whether this activity is still required to maintain the phenotype of terminally differentiated cardiomyocytes. Our results demonstrate that reducing the H3K4me3 marks is sufficient to alter gene expression patterns and significantly augment systolic heart function. These results clearly show that maintenance of H3K4me3 marks is necessary for the stability of the transcriptional program in differentiated cells. The array we performed allowed us to identify genes that are regulated by PTIP and histone methylation. 8-week-old littermate mice on a mixed C57B6 and B6129 background were utilized. Three mice were on a background with a PTIP floxed allele and a wild type PTIP allele (PTIP+1, PTIP+2, PTIP+3). Three mice had a transgene that expresses a modified estrogen receptor -Cre recombinase fusion protein under the control of a cardiac-specific driver (alpha myosin heavy chain, Jackson Lab stock #005650) and a floxed PTIP allele and a null PTIP (PTIPKO1, PTIPKO2, PTIPKO3). Both groups of mice were injected with tamoxifen at 8 weeks of age. Tamoxifen deletes the floxed PTIP allele in the PTIPKO mice. 5 days after tamoxifen injection, RNA was harvested from left ventricle (LV) apices in both groups. RNA was then sent to the University of Michigan microarray facility core for analysis.
Project description:Drosophila Kc167 cells were used to test the function of PTIP in regulating gene expression before and after loss of polycomb function. Four condtions were tested using dsRNA knockdowns (RNAi)