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.
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.
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).
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.
Project description:This study uses whole methylome sequencing to characterize the methylomes of mouse embryonic fibroblasts (MEF's). Two conditions were analyzed, MEF cells with intact TET1/TET2 enzymes (WT) and MEF cells with TET1/TET2 knocked out (DKO). Our results identify sets of differentially methylated genes which are correlated with TET1/TET2 induced expression changes of the corresponding genes. Whole methylome analysis of M. musculus MEF cells. Two conditions were sequenced and analyzed, the first is wild type (WT), the second (DKO) corresponds to knock-out of TET1 and TET2 enzymes.
Project description:In this study: (1) we distinguished Tet2 target genes that are regulated by its catalytic vs. noncatalytic functions in ESCs by transcriptomic profiling of Tet2 wildtype (WT), Tet2 catalytic mutant (Mut), and Tet2 knockout (KO) mouse ESCs by RNA-seq. (2) We mapped genome-wide DNA methylation of Tet2-WT, Tet2-Mut, and Tet2-KO ESCs by WGBS, to establish a critical role for Tet2 in demethylating promoters and enhancers of its catalytic target genes. (3) We determined how the genome-wide occupancy of the epigenetic modifiers Sin3a and Sap30 and the enrichment of H3K27ac, are affected in Tet2-Mut and Tet2-KO ESCs versus Tet2-WT by CUT&Tag and identified that Tet2 deficiency diminishes Sin3a occupancy at promoters and enhancers. (4) We mapped Sin3a levels genome-wide in Tet1/2 double catalytic mutant (DMUT) and Tet1/2 double knockout (DKO) ESCs, and found that deficiency of both Tet1 and Tet2 resulted in decreased levels of Sin3a in a subset of active enhancers.
Project description:This study uses whole-transcriptome sequencing to characterize the transcriptomes of mouse embryonic fibroblasts (MEF's). Two conditions were analyzed, MEF cells with intact TET1/TET2 enzymes (WT) and MEF cells with TET1/TET2 knocked out (DKO). Our results identify sets of differentially expressed genes which are correlated with TET1/TET2 induced methylation changes of the corresponding genes. Whole transcriptome analysis of M. musculus MEF cells. Two conditions were sequenced and analyzed, the first is wild type (WT), the second corresponds to knock-out of TET1 and TET2 enzymes.
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.
Project description:This study uses whole methylome sequencing to characterize the methylomes of mouse embryonic fibroblasts (MEF's). Two conditions were analyzed, MEF cells with intact TET1/TET2 enzymes (WT) and MEF cells with TET1/TET2 knocked out (DKO). Our results identify sets of differentially methylated genes which are correlated with TET1/TET2 induced expression changes of the corresponding genes.
Project description:This study uses whole-transcriptome sequencing to characterize the transcriptomes of mouse embryonic fibroblasts (MEF's). Two conditions were analyzed, MEF cells with intact TET1/TET2 enzymes (WT) and MEF cells with TET1/TET2 knocked out (DKO). Our results identify sets of differentially expressed genes which are correlated with TET1/TET2 induced methylation changes of the corresponding genes.