Project description:We found a small molecule-DKG, relative to Vitamin C, could replace the function of Viamin C during reprogramming. After comparing transcriptome profiling (RNA-seq) of this molecule to vitamin C, it could provide a framework for more mechanism.
Project description:Tet1 is a hydroxylase known for its role in the conversion of 5-methylcytosines (5mC) to 5-hydroxymethylcytosines (5hmC) involved in the possible active demethylation process and gene expression regulation1-5.M-BM- As somatic cell reprogramming involves the re-activation of pluripotency genes and the silencing of somatic ones6, it remains unclear whether Tet1 plays a positive or negative role in the reprogramming process. Here we show that Tet1 deficiency enhances reprogramming and its overexpression impairs reprogramming. Mechanistically, we demonstrated that Tet1 represses the early obligatory process of mesenchymal to epithelial transition (MET) during reprogramming7,8. Thus, our findings not only define a negative role for Tet1 in somatic cell reprogramming, but also suggest that the Tet enzymes regulate cell fate through distinctive mechanisms. Examination of genome DNA hmC modifications in 2 conditions: individually overexpressed Tet1CD or Tet2CD during MEF reprogramming; Examination of mRNA levels in five different conditions: individually overexpressed DR or Tet1CD or Tet1CDmut or Tet2CD or Tet2CDmut, during MEF reprogrammig.
Project description:Tet1 is a hydroxylase known for its role in the conversion of 5-methylcytosines (5mC) to 5-hydroxymethylcytosines (5hmC) involved in the possible active demethylation process and gene expression regulation. As somatic cell reprogramming involves the re-activation of pluripotency genes and the silencing of somatic ones, it remains unclear the role of Tet1 in the reprogramming process. Here, we performed hMeDIP-seq and RNA-seq during somatic cells reprogramming with Tet1 over expression to invest the effect of Tet1.
Project description:Ten-eleven translocation (TET) family enzymes can convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) in DNA and have been proposed as potential DNA demethylase candidates1. Evidences from recent studies indicated that Tet1 is predominantly expressed in ES cells and plays dual functions in promoting transcription of pluripotency genes and as well as participating in the repression of developmental genes by facilitating recruitment of PRC21-5. These studies further raised the possibility that Tet1 might play a role in somatic cell reprogramming. Here, we provide evidence showing that Tet1 can substitute for pluripotent transcription factors in reprogramming differentiated somatic cells to pluripotent stem cells. Tet1 can replace any one of the four traditional transcription factors including Oct4, Sox2, Klf4 and c-Myc during somatic cell reprogramming. Subsequently, the chimeric mice with germline transmission capacity could be efficiently produced from all induced pluripotent stem (iPS) cell lines reprogrammed by OT (Oct4, Tet1), TSKM (Tet1, Sox2, Klf4, c-Myc), OTK, OTKM and OSTM combinations. Furthermore, the TSKM-reprogrammed iPS cells without using Oct4 could produce viable full-term iPS mice with normal fertility through tetraploid complementation and secondary iPS cells could be induced subsequently from the somatic cells retrieved from the iPS mice. Moreover, we demonstrated that conversion of 5mC into 5hmC in Nanog promoter occurred during reprogramming, which might account in part for the mechanism of Tet1 mediated reprogramming. To our knowledge, our study provides the first evidence demonstrating that DNA modifying enzyme Tet1 can replace the pluripotent transcription factors to reprogram differentiated somatic cells to iPS cells. Gene expression profile of iPS cells and ES cells were generated by Affymetrix Mouse Gene 1.0 ST Array. The Gene expression profile of ES cell R1 was used as control. Three biological repeats were included for each line.
Project description:Maternal Vitamin C is required in vivo for proper DNA demethylation and development of fetal germ cells in a mouse model of Vitamin C deficiency. Withdrawal of Vitamin C from the maternal diet does not affect overall embryonic development but leads to defects in the fetal germline, which persist well after Vitamin C re-supply during late gestation. The transcriptome of germ cells from Vitamin C-deficient embryos is remarkably similar to that of embryos carrying a mutation in Tet1, which is responsible for DNA demethylation and activation of regulators of meiosis. In agreement with these results, Vitamin C deficiency leads to an aberrant DNA methylation profile that includes incomplete demethylation of key regulators of meiosis and transposable elements. These findings reveal that deficiency in Vitamin C during gestation recapitulates a mutation in Tet1 and disrupts germline reprogramming and development. Our work further indicate that the embryonic germline is sensitive to perturbations of the maternal diet, providing a potential intergenerational mechanism for adjusting fecundity to environmental quality.
Project description:Maternal Vitamin C is required in vivo for proper DNA demethylation and development of fetal germ cells in a mouse model of Vitamin C deficiency. Withdrawal of Vitamin C from the maternal diet does not affect overall embryonic development but leads to defects in the fetal germline, which persist well after Vitamin C re-supply during late gestation. The transcriptome of germ cells from Vitamin C-deficient embryos is remarkably similar to that of embryos carrying a mutation in Tet1, which is responsible for DNA demethylation and activation of regulators of meiosis. In agreement with these results, Vitamin C deficiency leads to an aberrant DNA methylation profile that includes incomplete demethylation of key regulators of meiosis and transposable elements. These findings reveal that deficiency in Vitamin C during gestation recapitulates a mutation in Tet1 and disrupts germline reprogramming and development. Our work further indicate that the embryonic germline is sensitive to perturbations of the maternal diet, providing a potential intergenerational mechanism for adjusting fecundity to environmental quality.
Project description:Maternal Vitamin C is required in vivo for proper DNA demethylation and development of fetal germ cells in a mouse model of Vitamin C deficiency. Withdrawal of Vitamin C from the maternal diet does not affect overall embryonic development but leads to defects in the fetal germline, which persist well after Vitamin C re-supply during late gestation. The transcriptome of germ cells from Vitamin C-deficient embryos is remarkably similar to that of embryos carrying a mutation in Tet1, which is responsible for DNA demethylation and activation of regulators of meiosis. In agreement with these results, Vitamin C deficiency leads to an aberrant DNA methylation profile that includes incomplete demethylation of key regulators of meiosis and transposable elements. These findings reveal that deficiency in Vitamin C during gestation recapitulates a mutation in Tet1 and disrupts germline reprogramming and development. Our work further indicate that the embryonic germline is sensitive to perturbations of the maternal diet, providing a potential intergenerational mechanism for adjusting fecundity to environmental quality.
Project description:Maternal Vitamin C is required in vivo for proper DNA demethylation and development of fetal germ cells in a mouse model of Vitamin C deficiency. Withdrawal of Vitamin C from the maternal diet does not affect overall embryonic development but leads to defects in the fetal germline, which persist well after Vitamin C re-supply during late gestation. The transcriptome of germ cells from Vitamin C-deficient embryos is remarkably similar to that of embryos carrying a mutation in Tet1, which is responsible for DNA demethylation and activation of regulators of meiosis. In agreement with these results, Vitamin C deficiency leads to an aberrant DNA methylation profile that includes incomplete demethylation of key regulators of meiosis and transposable elements. These findings reveal that deficiency in Vitamin C during gestation recapitulates a mutation in Tet1 and disrupts germline reprogramming and development. Our work further indicate that the embryonic germline is sensitive to perturbations of the maternal diet, providing a potential intergenerational mechanism for adjusting fecundity to environmental quality.
Project description:Cardiomyocyte-like cells can be reprogrammed from somatic fibroblasts by overexpression of cardiac genes, providing a new avenue for cardiac regenerative therapy. Here we report an alternative approach in which functional cardiomyocytes can be rapidly and efficiently generated from human fibroblasts by a specific combination of small molecules. ChIP-seq analysis has been used to understand the dynamic changes in chromatin state during early stage of reprogramming. We analyzed the genome-wide epigenetic changes by ChIP-seq analysis of H3K4me3 and H3K27ac (active chromatin marks) and H3K27me3 (inactive chromatin mark) at reprogramming Day 6 (D6) and day 11 (D11).
Project description:Precise regulation of DNA methylation in mammals is critical for genome stability and epigenetic regulation. The discovery of the ten-eleven translocation (TET) proteins catalyzing the oxidation from 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) revolutionized the perspective on the complexity and regulation of DNA modifications. Despite accumulating knowledge about the role of TET1, it remains unclear to what extent these can be attributed to its catalytic activity. Here, we use genome engineering and quantitative multi-omics approaches to dissect the role and mechanism of TET1 in mESCs. Our study identifies TET1 as an essential interaction hub for multiple chromatin modifying complexes and as a global regulator of histone modifications. Strikingly, we find that the majority of transcriptional regulation depends on non-catalytic functions of TET1. Moreover, we show that the establishment of H3K9me3 and H4K20me3 at ERV1, ERVK, and ERVL is mediated by TET1 independent of DNA demethylation. We provide evidence that repression of endogenous retroviruses depends on the interaction between TET1 and SIN3A. In summary, we demonstrate that the non-catalytic functions of TET1 are critical for regulation of gene expression and the silencing of endogenous retroviruses in mESCs.