Project description:TET enzymes are dioxygenases that promote DNA demethylation by oxidizing the methyl group of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Here we report a close correspondence between 5hmC-marked regions, chromatin accessibility and enhancer activity in B cells, and a strong enrichment for consensus binding motifs for basic region-leucine zipper (bZIP) transcription factors at TET-responsive genomic regions. Functionally, Tet2 and Tet3 regulate class switch recombination (CSR) in murine B cells by enhancing expression of Aicda, encoding the cytidine deaminase AID essential for CSR. TET enzymes deposit 5hmC, demethylate and maintain chromatin accessibility at two TET-responsive elements, TetE1 and TetE2, located within a superenhancer in the Aicda locus. Transcriptional profiling identified BATF as the bZIP transcription factor involved in TET-dependent Aicda expression. 5hmC is not deposited at TetE1 in activated Batf-deficient B cells, indicating that BATF recruits TET proteins to the Aicda enhancer. Our data emphasize the importance of TET enzymes for bolstering AID expression, and highlight 5hmC as an epigenetic mark that captures enhancer dynamics during cell activation.
Project description:We sequenced cDNA prepared from ribosomal RNA depleted total RNA of 10-10 embryos co-injected with TBP-,TBP2- and TLF-AS antisense oligonucleotides and with water to create expression profiles of triple knockdown of TBP/TBP-related factors (TKD) and control, respectively, in Xenopus laevis at early developmental stage 10.5. (according to Nieuwkoop and Faber). We executed differential expression analysis of sequence count data (DEseq).
Project description:To explore the effects of Tet on porcine pre-implantation embryogenesis, we utilized Bobcat339, a specific small-molecule inhibitor of the Tet protein, to treat parthenogenetic 4-cell stage embryos.
Project description:TET enzymes mediate DNA demethylation by oxidizing 5-methylcytosine (5mC) in DNA to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Because these oxidized methylcytosines (oxi-mC) are not recognized by the maintenance methyltransferase DNMT1, DNA demethylation can occur through “passive”, replication-dependent dilution as cells divide. A distinct, replication-independent (“active”) mechanism of DNA demethylation involves excision of 5fC and 5caC by the DNA repair enzyme thymine DNA glycosylase (TDG), followed by base excision repair. Here we used inducible gene-disrupted mice to show that TET enzymes influence both replication-dependent primary T cell differentiation and replication-independent macrophage differentiation, whereas TDG has no effect. Mice with long-term (1 year) deletion of Tdg are healthy and show normal survival and hematopoiesis. In summary, TET enzymes regulate differentiation and DNA demethylation primarily through passive dilution of oxidized methylcytosines in replicating T cells, and active, replication-independent DNA demethylation mediated by TDG does not appear to be essential for immune cell activation or differentiation.
Project description:The tumorigenesis capacity of MLL-AF4 alone is insufficient for causing leukemia. Based on the finding that an Flt3 gene mutation in the tyrosine kinase domain (TKD) was observed in approximately 15% of MLL leukemia, we investigated synergistic leukemogenesis effects of the two genes in vitro. In a mouse IL3-dependent cell line, 32Dc, the expression of MLL-AF4 and Flt3 TKD was induced using a lentiviral vector. We performed gene expression profiling in the MLL-AF4 and the Flt3 TKD+MLL-AF4 expressing 32Dc cells. The enhancement of Hox genes expression was not identified. However, instead, the expression of S100A6, which was involved in the control of cell proliferation, was synergistically enhanced in the presence of both MLL-AF4 and Flt3 TKD genes. We performed gene expression profiling: 32Dc vs. MLL-AF4 expressing 32Dc, 32Dc vs. Flt3 TKD+MLL-AF4 expressing 32Dc, and MLL-AF4 expressing 32Dc vs. Flt3 TKD+MLL-AF4 expressing 32Dc. A single sample for each expressing cells was analyzed.
Project description:The Ten-eleven translocation (TET) family of dioxygenases can mediate cytosine demethylation by catalyzing the oxidation of 5-methylcytosine (5mC). TET-mediated DNA demethylation controls the proper differentiation of embryonic stem cells and TET proteins display functional redundancy during early gastrulation. However, it is unclear if TET proteins have functional significance in mammalian skeletal development. Here, we report that Tet deficiency in mesoderm mesenchymal stem cells results in severe defects of bone development. The existence of any single Tet gene allele can support early bone formation, suggesting a potential functional redundancy of TET proteins. Integrative analyses of RNA-seq, Whole Genome Bisulfite Sequencing (WGBS) and Assay for Transposase-Accessible Chromatin (ATAC-seq) demonstrate that TET-mediated demethylation increases the chromatin accessibility of target genes by RUNX2 and facilities RUNX2-regulated transcription. In addition, TET proteins interact with RUNX2 through their catalytic domain to regulate cytosine methylation around RUNX2 binding region. The catalytic domain is indispensable for TET proteins to regulate RUNX2 transcription activity on its target genes and to regulate bone development. These results demonstrate that TET proteins function redundantly to regulate RUNX2 activity via dual mechanisms and maintain skeletal homeostasis.
Project description:The tumorigenesis capacity of MLL-AF4 alone is insufficient for causing leukemia. Based on the finding that an Flt3 gene mutation in the tyrosine kinase domain (TKD) was observed in approximately 15% of MLL leukemia, we investigated synergistic leukemogenesis effects of the two genes in vitro. In a mouse IL3-dependent cell line, 32Dc, the expression of MLL-AF4 and Flt3 TKD was induced using a lentiviral vector. We performed gene expression profiling in the MLL-AF4 and the Flt3 TKD+MLL-AF4 expressing 32Dc cells. The enhancement of Hox genes expression was not identified. However, instead, the expression of S100A6, which was involved in the control of cell proliferation, was synergistically enhanced in the presence of both MLL-AF4 and Flt3 TKD genes.
