Ten-eleven translocation (Tet) family of DNA dioxygenases converts 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5- carboxylcytosine (5caC) through iterative oxidation reactions. While 5mC and 5hmC are relatively abundant, 5fC and 5caC are at very low levels in the mammalian genome. Thymine DNA glycosylase (TDG) and base excision repair (BER) pathways can actively remove 5fC/5caC to regenerate unmethylated cytosine, but it is unclear to what extent and at which part of the genome such active demethylation processes take place. Here, we have performed high-throughput sequencing analysis of 5mC/5hmC/5fC/5caC- enriched DNA using modification-specific antibodies and generated genome-wide distribution maps of these cytosine modifications in wild-type and Tdg-deficient mouse embryonic stem cells (ESCs). We observe that the steady state 5fC and 5caC are preferentially detected at repetitive sequences in wild-type mouse ESCs. Depletion of TDG causes marked accumulation of 5fC and 5caC at a large number of distal gene regulatory elements and transcriptionally repressed/poised gene promoters, suggesting that Tet/TDG-dependent dynamic cycling of 5mC oxidation states may be involved in regulating the function of these regions. Thus, comprehensive mapping of 5mC oxidation and BER pathway activity in the mammalian genome provides a promising approach for better understanding of biological roles of DNA methylation and demethylation dynamics in development and diseases.
Genome-wide analysis reveals TET- and TDG-dependent 5-methylcytosine oxidation dynamics.
Specimen part
View SamplesTen-eleven translocation (Tet) family of DNA dioxygenases converts 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5- carboxylcytosine (5caC) through iterative oxidation reactions. While 5mC and 5hmC are relatively abundant, 5fC and 5caC are at very low levels in the mammalian genome. Thymine DNA glycosylase (TDG) and base excision repair (BER) pathways can actively remove 5fC/5caC to regenerate unmethylated cytosine, but it is unclear to what extent and at which part of the genome such active demethylation processes take place. Here, we have performed high-throughput sequencing analysis of 5mC/5hmC/5fC/5caC- enriched DNA using modification-specific antibodies and generated genome-wide distribution maps of these cytosine modifications in wild-type and Tdg-deficient mouse embryonic stem cells (ESCs). We observe that the steady state 5fC and 5caC are preferentially detected at repetitive sequences in wild-type mouse ESCs. Depletion of TDG causes marked accumulation of 5fC and 5caC at a large number of distal gene regulatory elements and transcriptionally repressed/poised gene promoters, suggesting that Tet/TDG-dependent dynamic cycling of 5mC oxidation states may be involved in regulating the function of these regions. Thus, comprehensive mapping of 5mC oxidation and BER pathway activity in the mammalian genome provides a promising approach for better understanding of biological roles of DNA methylation and demethylation dynamics in development and diseases.
Genome-wide analysis reveals TET- and TDG-dependent 5-methylcytosine oxidation dynamics.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dual functions of Tet1 in transcriptional regulation in mouse embryonic stem cells.
Specimen part, Disease, Treatment
View SamplesWe examined early and late gene expression changes using the IT LPS model of Acute Lung Injury (ALI). In this model, injury peaks at day 4 and is almost completely resolved by day 10 in wild type (WT) C57BL/6 mice. In contrast to the pattern in WT mice, lymphocyte-deficient Rag-1 -/- mice exhibit strikingly delayed resolution despite similar initial injury.
Regulatory T cell-mediated resolution of lung injury: identification of potential target genes via expression profiling.
Sex, Specimen part, Treatment, Time
View SamplesEpigenetic modification of the mammalian genome by DNA methylation (5-methylcytosine) has a profound impact on chromatin structure, gene expression and maintenance of cellular identity. Recent demonstration that members of the Ten-eleven translocation (Tet) family proteins can convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) raised the possibility that Tet proteins are capable of establishing a distinct epigenetic state. We have recently demonstrated that Tet1 is specifically expressed in murine embryonic stem (ES) cells and is required for ES cell self-renewal and maintenance. Using chromatin immunoprecipitation coupled with high-throughput DNA sequencing (ChIP-seq), here we show that Tet1 is preferentially bound to CpG-rich sequences at promoters of both transcriptionally active and Polycomb-repressed genes. Despite a general increase in levels of DNA methylation at Tet1 binding-sites, Tet1 depletion does not lead to down-regulation of all the Tet1 targets. Interestingly, while Tet1-mediated promoter hypomethylation is required for maintaining the expression of a group of transcriptionally active genes, it is also required for repression of Polycomb-targeted developmental regulators. Tet1 contributes to silencing of this group of genes by facilitating recruitment of PRC2 to CpG-rich gene promoters. Thus, our study not only establishes a role for Tet1 in modulating DNA methylation levels at CpG-rich promoters, but also reveals a dual function of Tet1 in promoting transcription of pluripotency factors as well as participating in the repression of Polycomb-targeted developmental regulators.
Dual functions of Tet1 in transcriptional regulation in mouse embryonic stem cells.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Direct lineage conversion of adult mouse liver cells and B lymphocytes to neural stem cells.
Specimen part
View SamplesThe overexpression of transcription factors Oct4, Sox2, Klf4, and c-Myc reprograms a somatic nucleus to one that is transcriptionally and epigenetically indistinguishable from an embryonic stem (ES) cell. However, it is still unclear if transcription factors can completely convert the nucleus of a differentiated cell into that of a distantly related cell type such that it maintains complete transcriptional and epigenetic reprogramming in the absence of exogenous factor expression. To test this idea, we screened a library of doxycycline-inducible vectors encoding neural stem cell (NSC)-expressed genes and found that stable, self-maintaining NSC-like cells could be induced under defined growth conditions after transduction of transcription factors. These induced NSCs (iNSCs) were characterized in the absence of exogenous factor induction and were shown to be transcriptionally, epigenetically, and functionally similar to endogenous embryonic cortical NSCs. Importantly, iNSCs could be generated from multiple adult cell types including liver cells and B-cells with genetic rearrangements. Our results show that self-maintaining proliferative neural cells can be induced from non-ectodermal cells by expressing specific combinations of transcription factors.
Direct lineage conversion of adult mouse liver cells and B lymphocytes to neural stem cells.
Specimen part
View SamplesRNA sequencing data for replicates of E347 driver control, E347 neuronal ablation per Shi dominant-negative expression and activation per NachBac expression to identify differences in RNA abundancy Overall design: E347 driver control, E347 neuronal ablation per Shi dominant-negative expression and activation per NachBac expression
Coordination between Drosophila Arc1 and a specific population of brain neurons regulates organismal fat.
Specimen part, Subject
View SamplesThe retinal pigment epithelium (RPE) provides vital support to photoreceptor cells and its dysfunction is associated with the onset and progression of age-related macular degeneration (AMD). Surgical provision of RPE cells may ameliorate AMD and thus it would be valuable to develop sources of patient-matched RPE cells for this application of regenerative medicine. We describe here the generation of functional RPE-like cells from fibroblasts that represent an important step toward that goal. We identified candidate master transcriptional regulators of RPEs using a novel computational method and then used these regulators to guide exploration of the transcriptional regulatory circuitry of RPE cells and to reprogram human fibroblasts into RPE-like cells. The RPE-like cells share key features with RPEs derived from healthy individuals, including morphology, gene expression and function, and thus represent a step toward the goal of generating patient-matched RPE cells for treatment of macular degeneration.
A Systematic Approach to Identify Candidate Transcription Factors that Control Cell Identity.
Specimen part
View SamplesPreviously we had shown in a mouse model of bronchial asthma that thrombomodulin (TM; CD141; BDCA3) can convert immunogenic conventional dendritic cells into tolerogenic dendritic cells while inducing its own expression on the cell surface. Thrombomodulin+ dendritic cells are tolerogenic while thrombomodulin- dendritic cells are pro-inflammatory and immunogenic. Here we hypothesized that thrombomodulin treatment of dendritic cells would modulate inflammatory gene expression. Murine bone marrow derived dendritic cells were treated with soluble thrombomodulin and expression of surface markers was determined. Treatment with thrombomodulin reduces the expression of maturation markers and increases the expression of TM on the DC surface. Thrombomodulin treated and control dendritic cells were sorted into thrombomodulin+ and thrombomodulin- dendritic cells before their mRNA was analyzed by microarray. mRNAs encoding pro-inflammatory genes and dendritic cells maturation markers were reduced while cell cycle genes were increased in thrombomodulin-treated and thrombomodulin+ dendritic cells compared to control dendritic cells and thrombomodulin- dendritic cells.
Differential gene expression in thrombomodulin (TM; CD141)(+) and TM(-) dendritic cell subsets.
Specimen part
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