Project description:TET-family dioxygenases oxidize 5-methylcytosine (5mC) in DNA, and exert tumor suppressor activity in many types of cancers. Even in the absence of TET coding region mutations, TET loss-of-function is strongly associated with cancer. We show that acute elimination of TET function induces the rapid development of an aggressive, fully-penetrant and cell-autonomous myeloid leukemia in mice, pointing to a causative role for TET-loss-of-function in this myeloid malignancy. Phenotypic and transcriptional profiling showed aberrant differentiation of hematopoietic stem/ progenitor cells, impaired erythroid and lymphoid differentiation and strong skewing to the myeloid lineage, with only a mild relation to changes in DNA modification. We also observed progressive accumulation of DNA damage and strong impairment of DNA break repair, suggesting a key role for TET proteins in maintaining genomic integrity.
Project description:To evaluate the DNA methylation in LSK cells from the bone marrow of wildtype or Tet2/3 DKO mice. In order to address the impact of the loss of Tet2/3 proteins in DNA methylation in LSK cells, we compared by WGBS the methylome of wild and, Tet2/3 DKO LSK cells in bone marrow.
Project description:The three mammalian TET dioxygenases oxidize the methyl group of 5-methylcytosine (5mC) in DNA, and the oxidised methylcytosines are essential intermediates in all known pathways of DNA demethylation. To define the in vivo consequences of complete TET deficiency, we inducibly deleted all three Tet genes in the mouse genome. Tet1/2/3 inducible TKO (iTKO) mice succumbed to acute myeloid leukaemia by 4-5 weeks. Single-cell RNA sequencing of Tet iTKO bone marrow cells revealed the appearance of new myeloid cell populations characterised by a striking increase in expression of all members of the stefin/cystatin gene cluster on mouse chromosome 16. In patients with acute myeloid leukaemia, high stefin/cystatin gene expression correlates with poor clinical outcomes. Increased expression of the clustered stefin/cystatin genes was associated with a heterochromatin-to-euchromatin compartment switch with readthrough transcription downstream of the clustered stefin/cystatin genes as well as other highly expressed genes but only minor changes in DNA methylation. Our data highlight new roles for TET enzymes that are distinct from their established function in DNA demethylation, and instead involve increased transcriptional readthrough and changes in three-dimensional genome organisation.
Project description:The three mammalian TET dioxygenases oxidize the methyl group of 5-methylcytosine (5mC) in DNA, and the oxidised methylcytosines are essential intermediates in all known pathways of DNA demethylation. To define the in vivo consequences of complete TET deficiency, we inducibly deleted all three Tet genes in the mouse genome. Tet1/2/3 inducible TKO (iTKO) mice succumbed to acute myeloid leukaemia by 4-5 weeks. Single-cell RNA sequencing of Tet iTKO bone marrow cells revealed the appearance of new myeloid cell populations characterised by a striking increase in expression of all members of the stefin/cystatin gene cluster on mouse chromosome 16. In patients with acute myeloid leukaemia, high stefin/cystatin gene expression correlates with poor clinical outcomes. Increased expression of the clustered stefin/cystatin genes was associated with a heterochromatin-to-euchromatin compartment switch with readthrough transcription downstream of the clustered stefin/cystatin genes as well as other highly expressed genes but only minor changes in DNA methylation. Our data highlight new roles for TET enzymes that are distinct from their established function in DNA demethylation, and instead involve increased transcriptional readthrough and changes in three-dimensional genome organisation.
Project description:The three mammalian TET dioxygenases oxidize the methyl group of 5-methylcytosine (5mC) in DNA, and the oxidised methylcytosines are essential intermediates in all known pathways of DNA demethylation. To define the in vivo consequences of complete TET deficiency, we inducibly deleted all three Tet genes in the mouse genome. Tet1/2/3 inducible TKO (iTKO) mice succumbed to acute myeloid leukaemia by 4-5 weeks. Single-cell RNA sequencing of Tet iTKO bone marrow cells revealed the appearance of new myeloid cell populations characterised by a striking increase in expression of all members of the stefin/cystatin gene cluster on mouse chromosome 16. In patients with acute myeloid leukaemia, high stefin/cystatin gene expression correlates with poor clinical outcomes. Increased expression of the clustered stefin/cystatin genes was associated with a heterochromatin-to-euchromatin compartment switch with readthrough transcription downstream of the clustered stefin/cystatin genes as well as other highly expressed genes but only minor changes in DNA methylation. Our data highlight new roles for TET enzymes that are distinct from their established function in DNA demethylation, and instead involve increased transcriptional readthrough and changes in three-dimensional genome organisation.
Project description:The three mammalian TET dioxygenases oxidize the methyl group of 5-methylcytosine (5mC) in DNA, and the oxidised methylcytosines are essential intermediates in all known pathways of DNA demethylation. To define the in vivo consequences of complete TET deficiency, we inducibly deleted all three Tet genes in the mouse genome. Tet1/2/3 inducible TKO (iTKO) mice succumbed to acute myeloid leukaemia by 4-5 weeks. Single-cell RNA sequencing of Tet iTKO bone marrow cells revealed the appearance of new myeloid cell populations characterised by a striking increase in expression of all members of the stefin/cystatin gene cluster on mouse chromosome 16. In patients with acute myeloid leukaemia, high stefin/cystatin gene expression correlates with poor clinical outcomes. Increased expression of the clustered stefin/cystatin genes was associated with a heterochromatin-to-euchromatin compartment switch with readthrough transcription downstream of the clustered stefin/cystatin genes as well as other highly expressed genes but only minor changes in DNA methylation. Our data highlight new roles for TET enzymes that are distinct from their established function in DNA demethylation, and instead involve increased transcriptional readthrough and changes in three-dimensional genome organisation.