Combined deficiency of Tet1 and Tet2 is compatible with development but leads to epigenetic instability
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE42396 | GEO | 2013/02/01
SECONDARY ACCESSION(S): PRJNA181954
REPOSITORIES: GEO
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Project description:Tet enzymes (Tet1/2/3) convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC). Tet1 and Tet2 mediate 5hmC generation in mouse embryonic stem cells (ESCs) and various embryonic and adult tissues. To investigate the effects of combined deficiency of Tet1 and Tet2 on pluripotency and development, we have generated Tet1 and Tet2 double knockout (DKO) ESCs and mice. DKO ESCs were depleted of 5hmC, but remained pluripotent with subtle defects in differentiation and changes in gene expression. Double mutant embryos and chimeras exhibited mid-gestation defects and postnatal DKO mice displayed partially penetrant neonatal lethality and stochastic perturbation of imprinting. Viable DKO animals developed normally to adulthood but had reduced 5hmC level, increased 5mC level and lacked 5hmC in germ cells. Nevertheless, DKO mice of both sexes were fertile with females having smaller ovaries and reduced fertility. Our data suggest that both Tet1 and Tet2 contribute to 5hmC levels during development. Their combined loss does not block differentiation and embryogenesis, but leads to partially penetrant embryonic and perinatal abnormalities and compromised viability. Moreover, the presence of substantial levels of 5hmC in DKO embryos and adult mice suggests a significant contribution of Tet3 in hydroxylation of 5mC during development. Methylation patterns in tissue samples from a series of wt and Tet1/Tet2 DKO embryos, neonates and adults were generated using methylated DNA immunoprecipitation with antibodies against 5mC (MeDIP) and 5hmC (hMeDIP) followed by deep sequencing.
2013-02-01 | E-GEOD-42396 | biostudies-arrayexpress
Project description:TET1/2/3 are methylcytosine dioxygenases regulating cytosine hydroxymethylation in the genome. Tet1 and Tet2 are abundantly expressed in HSC/HPCs and implicated in the pathogenesis of hematological malignancies. Tet2-deletion in mice causes myeloid malignancies, while Tet1-null mice develop B-cell lymphoma after an extended period of latency. Interestingly, TET1 and TET2 were often concomitantly down-regulated in acute B-lymphocytic leukemia. Here, we investigated the overlapping and non-redundant functions of Tet1/Tet2 in HSC maintenance and development of hematological malignancies using Tet1/2 double knockout (DKO) mice. DKO and Tet2-/- HSC/HPCs had overlapping and unique 5hmC and 5mC profiles and behaved differently. DKO mice exhibited strikingly decreased incidence and delayed onset of myeloid malignancies compared to Tet2-/- mice and in contrast developed lethal B-cell malignancies. Transcriptome analysis of DKO tumors revealed expression changes in many genes dysregulated in human B-cell malignancies, such as LMO2, BCL6 and MYC. These results highlight the critical roles of TET1 or TET2 individually and their cross-talks in the pathogenesis of hematological malignancies. Given the role of Tet proteins in 5mC oxidation, we employed a previously established chemical labeling and affinity purification method coupled with high-throughput sequencing (hMe-Seal) to profile the genome-wide distribution of 5hmC, as well as methylated DNA immunoprecipitation (MeDIP) coupled with high-throughput sequencing (MeDIP-seq) to profile 5mC using BM LK cells purified from young WT, Tet2-/- and DKO mice (6-10 wks old).
2015-11-12 | E-GEOD-73611 | biostudies-arrayexpress
Project description:Cytosine DNA bases can be methylated by DNA methyltransferases and subsequently oxidized by TET proteins. The resulting 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) are considered demethylation intermediates as well as stable epigenetic marks. To dissect the contribution of these cytosine modifying enzymes, we generated combinations of Tet knockout (KO) embryonic stem cells (ESCs) and systematically measured protein and DNA modification levels at the transition from naive to primed pluripotency. Whereas the increase of genomic 5-methylcytosine (5mC) levels during exit from pluripotency correlated with an upregulation of the de novo DNA methyltransferases DNMT3A and DNMT3B, the subsequent oxidation steps turned out to be far more complex. The strong increase of oxidized cytosine bases (5hmC, 5fC, and 5caC) was accompanied by a drop in TET2 levels, yet the analysis of KO cells suggested that TET2 is responsible for most 5fC formation. The comparison of modified cytosine and enzyme levels in Tet KO cells revealed distinct and differentiation-dependent contributions of TET1 and TET2 to 5hmC and 5fC formation arguing against a processive mechanism of 5mC oxidation. The apparent independent steps of 5hmC and 5fC formation suggest yet to be identified mechanisms regulating TET activity and may constitute another layer of epigenetic regulation.
2020-07-24 | PXD019514 | Pride
Project description:Tet enzymes (Tet1/2/3) catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and are dynamically expressed in various embryonic and adult cell types. While loss of individual Tet enzymes or combined deficiency of Tet1/2 allows for embryogenesis, the effect of complete loss of Tet activity and 5hmC marks in development has not been established. To define the role of Tet enzymes and 5hmC in development we have generated Tet1, Tet2 and Tet3 triple knockout (TKO) mouse embryonic stem cells (ESCs) and examined their developmental potential in vitro and in vivo. Combined deficiency of all three Tet enzymes led to complete depletion of 5hmC and impaired ESC differentiation as seen in poorly differentiated TKO embryoid bodies and teratomas. Consistent with impaired differentiation, TKO ES cells exhibited limited contribution to the chimeric embryos and could not support embryonic development in tetraploid complementation assays. Gene expression profiles and genome wide methylome analyses of TKO embryoid bodies revealed promoter hypermethylation and deregulation of genes implicated in embryonic development and differentiation. These findings suggest a requirement for Tet and 5hmC-mediated DNA demethylation in proper regulation of gene expression during differentiation of embryonic stem cells and development. Methylation patterns in tissue samples from a series of wt and Tet1/Tet2 DKO embryos, neonates and adults were generated using ethylated DNA immunoprecipitation with antibodies against 5mC (MeDIP) and 5hmC (hMeDIP) followed by deep sequencing.
2014-04-17 | E-GEOD-55049 | biostudies-arrayexpress
Project description:TET1/2/3 are methylcytosine dioxygenases regulating cytosine hydroxymethylation in the genome. Tet1 and Tet2 are abundantly expressed in HSC/HPCs and implicated in the pathogenesis of hematological malignancies. Tet2-deletion in mice causes myeloid malignancies, while Tet1-null mice develop B-cell lymphoma after an extended period of latency. Interestingly, TET1 and TET2 were often concomitantly down-regulated in acute B-lymphocytic leukemia. Here, we investigated the overlapping and non-redundant functions of Tet1/Tet2 in HSC maintenance and development of hematological malignancies using Tet1/2 double knockout (DKO) mice. DKO and Tet2-/- HSC/HPCs had overlapping and unique 5hmC and 5mC profiles and behaved differently. DKO mice exhibited strikingly decreased incidence and delayed onset of myeloid malignancies compared to Tet2-/- mice and in contrast developed lethal B-cell malignancies. Transcriptome analysis of DKO tumors revealed expression changes in many genes dysregulated in human B-cell malignancies, such as LMO2, BCL6 and MYC. These results highlight the critical roles of TET1 or TET2 individually and their cross-talks in the pathogenesis of hematological malignancies.
2015-11-12 | GSE73611 | GEO
Project description:Ten-eleven translocation (TET) proteins oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytsosine (5fC), and 5-carboxylcytosine (5caC). 5fC/5caC can be excised and repaired by the base excision repair (BER) pathway, implicating 5mC oxidation in active DNA demethylation. Genome-wide DNA methylation is erased in the transition from metastable states to ground state of embryonic stem cells (ESCs) and in migrating primordial germ cells (PGCs), while some resistant regions become demethylated only in gonadal PGCs. Understanding the mechanisms underlying global hypomethylation in naïve ESCs and developing PGCs will be useful for realizing cellular pluripotency and totipotency. In this study, we found that PRDM14, the PR-domain-containing transcriptional regulator, accelerates the TET-BER cycle, resulting in the promotion of active DNA demethylation in ESCs. Induction of PRDM14 expression rapidly removed the 5mC associated with transient elevation of 5hmC at pluripotency-associated genes, germline-specific genes, and imprinted loci but not across the entire genome, which resemble second wave of DNA demethylation in gonadal PGCs. PRDM14 physically interacts with TET1/TET2 and enhances the recruitment of TET1/TET2 at target loci. Knockdown of Tet1/Tet2 impaired transcriptional regulation and DNA demethylation by PRDM14. The repression of the BER pathway by administration of pharmacological inhibitors against APE1 and PARP1 and the knockdown of thymine DNA glycosylase (TDG) also impaired DNA demethylation by PRDM14. Furthermore, DNA demethylation induced by PRDM14 normally takes place in the presence of aphidicolin, which is an inhibitor of G1/S progression. Together, our analysis provides mechanistic insight into DNA demethylation in naive pluripotent stem cells and developing PGCs. To investigate the function of TET1/TET2 in transcriptional regulation by PRDM14 in ESCs, we exploited microarray analysis using total mRNA derived from Scramble, Scramble + PRDM14, Tet1/Tet2 KD, Tet1/Tet2 KD + PRDM14 mouse ESC.
2013-12-31 | E-GEOD-52598 | biostudies-arrayexpress
Project description:The TET proteins TET1, TET2 and TET3 constitute a new family of dioxygenases that utilize molecular oxygen and the cofactors Fe(II) and 2-oxoglutarate to convert 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and further oxidation products in DNA1-5. Here we show that Tet1 and Tet2 have distinct roles in regulating 5hmC deposition and gene expression in mouse embryonic stem cells (mESC). Tet1 depletion in mESC primarily diminishes 5hmC levels at transcription start sites (TSS), whereas Tet2 depletion is mostly associated with decreased 5hmC in gene bodies relative to TSS. 5hmC is enriched at exon start and end sites, especially in exons that are highly expressed, and is significantly decreased upon Tet2 knockdown at the boundaries of high-expressed exons that are selectively regulated by Tet2. In differentiating murine B cells, Tet2 deficiency is associated with selective exon exclusion in the gene encoding the transmembrane phosphatase CD45. Tet2 depletion is associated with increased 5hmC and decreased 5mC at promoters/ TSS regions, possibly because of the redundant activity of Tet1. Together, these data indicate a complex interplay between Tet1 and Tet2 in mESC, and show that loss-of-function of a single TET protein does not necessarily lead to loss of 5hmC and a corresponding gain of 5mC, as generally assumed. The relation between Tet2 loss-of-function and selective changes in exon expression could potentially explain the frequent occurrence of both TET2 loss-of-function mutations and mutations in proteins involved in pre-mRNA splicing in myeloid malignancies in humans. Gene and exon expression analysis in mESC, Tet1 knockdown mESC, and Tet2 knockdown mESC by RNA-sequencing. Mapping of 5-hydroxymethylcytosine in mESC, Tet1 knockdown mESC, and Tet2 knockdown mESC by anti-CMS-seq. Mapping of methylcytosine in mESC, and Tet2 kd mESC by MeDIP-seq.
2014-01-16 | E-GEOD-50200 | biostudies-arrayexpress
Project description:The TET proteins TET1, TET2 and TET3 constitute a new family of dioxygenases that utilize molecular oxygen and the cofactors Fe(II) and 2-oxoglutarate to convert 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and further oxidation products in DNA1-5. Here we show that Tet1 and Tet2 have distinct roles in regulating 5hmC deposition and gene expression in mouse embryonic stem cells (mESC). Tet1 depletion in mESC primarily diminishes 5hmC levels at transcription start sites (TSS), whereas Tet2 depletion is mostly associated with decreased 5hmC in gene bodies relative to TSS. 5hmC is enriched at exon start and end sites, especially in exons that are highly expressed, and is significantly decreased upon Tet2 knockdown at the boundaries of high-expressed exons that are selectively regulated by Tet2. In differentiating murine B cells, Tet2 deficiency is associated with selective exon exclusion in the gene encoding the transmembrane phosphatase CD45. Tet2 depletion is associated with increased 5hmC and decreased 5mC at promoters/ TSS regions, possibly because of the redundant activity of Tet1. Together, these data indicate a complex interplay between Tet1 and Tet2 in mESC, and show that loss-of-function of a single TET protein does not necessarily lead to loss of 5hmC and a corresponding gain of 5mC, as generally assumed. The relation between Tet2 loss-of-function and selective changes in exon expression could potentially explain the frequent occurrence of both TET2 loss-of-function mutations and mutations in proteins involved in pre-mRNA splicing in myeloid malignancies in humans. Gene and exon expression analysis in mESC, Tet1 knockdown mESC, and Tet2 knockdown mESC by RNA-sequencing. Mapping of 5-hydroxymethylcytosine in mESC, Tet1 knockdown mESC, and Tet2 knockdown mESC by anti-CMS-seq. Mapping of methylcytosine in mESC, and Tet2 kd mESC by MeDIP-seq.
2014-01-16 | E-GEOD-50198 | biostudies-arrayexpress
Project description:The TET proteins TET1, TET2 and TET3 constitute a new family of dioxygenases that utilize molecular oxygen and the cofactors Fe(II) and 2-oxoglutarate to convert 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and further oxidation products in DNA1-5. Here we show that Tet1 and Tet2 have distinct roles in regulating 5hmC deposition and gene expression in mouse embryonic stem cells (mESC). Tet1 depletion in mESC primarily diminishes 5hmC levels at transcription start sites (TSS), whereas Tet2 depletion is mostly associated with decreased 5hmC in gene bodies relative to TSS. 5hmC is enriched at exon start and end sites, especially in exons that are highly expressed, and is significantly decreased upon Tet2 knockdown at the boundaries of high-expressed exons that are selectively regulated by Tet2. In differentiating murine B cells, Tet2 deficiency is associated with selective exon exclusion in the gene encoding the transmembrane phosphatase CD45. Tet2 depletion is associated with increased 5hmC and decreased 5mC at promoters/ TSS regions, possibly because of the redundant activity of Tet1. Together, these data indicate a complex interplay between Tet1 and Tet2 in mESC, and show that loss-of-function of a single TET protein does not necessarily lead to loss of 5hmC and a corresponding gain of 5mC, as generally assumed. The relation between Tet2 loss-of-function and selective changes in exon expression could potentially explain the frequent occurrence of both TET2 loss-of-function mutations and mutations in proteins involved in pre-mRNA splicing in myeloid malignancies in humans. Gene and exon expression analysis in mESC, Tet1 knockdown mESC, and Tet2 knockdown mESC by RNA-sequencing. Mapping of 5-hydroxymethylcytosine in mESC, Tet1 knockdown mESC, and Tet2 knockdown mESC by anti-CMS-seq. Mapping of methylcytosine in mESC, and Tet2 kd mESC by MeDIP-seq.
2014-12-03 | E-GEOD-63771 | biostudies-arrayexpress
Project description:The TET family of dioxygenases catalyze conversion of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), but their involvement in establishing normal 5mC patterns during mammalian development and their contributions to aberrant control of 5mC during cellular transformation remains largely unknown. We depleted TET1, TET2, and TET3 by siRNA in a pluripotent embryonic carcinoma cell model and examined the impact on genome-wide 5mC and 5hmC patterns. TET1 depletion yielded widespread reduction of 5hmC, while depletion of TET2 and TET3 reduced 5hmC at a subset of TET1 targets suggesting functional co-dependence. TET2 or TET3-depletion also caused increased 5hmC, suggesting they play a major role in 5hmC removal. All TETs prevent hypermethylation throughout the genome, a finding dramatically illustrated in CpG island shores, where TET depletion resulted in prolific hypermethylation. Surprisingly, TETs also promote methylation, as hypomethylation was associated with 5hmC reduction. TET function was highly specific to chromatin environment: 5hmC maintenance by all TETs occurred at polycomb-marked chromatin and genes expressed at moderate levels; 5hmC removal by TET2 is associated with highly transcribed genes enriched for H3K4me3 and H3K36me3. Importantly, genes prone to hypermethylation in cancer become depleted of 5hmC with TET deficiency, suggesting the TETs normally promote 5hmC at these loci, and all three TETs are required for 5hmC enrichment at enhancers, a condition necessary for expression of adjacent genes. These results provide novel insight into the division of labor among TET proteins and reveal an important connection of TET activity with chromatin landscape and gene expression. Affymetrix gene expression Human ST1.0 microarray of NCCIT human embryonic carcinoma cells (4 samples in duplicate).
2014-06-14 | E-GEOD-51901 | biostudies-arrayexpress