A Werner syndrome stem cell model unveils heterochromatin alterations as a driver of human aging
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Jingyi Li
PROVIDER: E-GEOD-52285 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:TET1, the founding member of the TET family of enzymes (TET1/2/3) that convert 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), was first identified as a partner gene in MLL-rearranged leukemia, but its definitive pathological role in leukemia is unclear. The down-regulation of all three TET genes and loss-of-function mutations of TET2 have been frequently observed in various cancers, and it was thought that they all play tumor-suppressor roles in tumorigenesis. Here we show that TET1 is likely a direct target of MLL and significantly up-regulated in MLL-rearranged leukemia, associated with an increased level of 5hmC. Our further in vitro and in vivo studies demonstrate that Tet1 plays an indispensable oncogenic role in MLL-rearranged leukemia, through cooperating with MLL fusion proteins in regulating their co-targets including the Hoxa/Meis1/Pbx3/Flt3 genes. Our data delineate a MLL-fusion/Tet1/Hoxa/Meis1/Pbx3/Flt3 signaling axis in MLL-rearranged leukemia, and highlight TET1 as a potential therapeutic target in treating this presently therapy-resistant disease. We report genome-wide 5hmC enrichment profiles and RNA-Seq gene expression in MLL-AF9 transformed and control mouse bone marrow mononuclear cells. These 5hmC profiles are derived from selctive chemical labeling and enrichment of 5hmC containing genomic DNA fragments, while the RNA-Seq expression profiles are generated from polyA enriched RNA
2015-12-14 | E-GEOD-42990 | biostudies-arrayexpress
Project description:TET proteins convert 5-methylcytosine to 5-hydroxymethylcytosine, an emerging dynamic epigenetic state of DNA that can influence transcription. Evidence has linked TET1 function to epigenetic repression complexes, yet mechanistic information, especially for the TET2 and TET3 proteins, remains limited. Here, we show a direct interaction of TET2 and TET3 with O-GlcNAc transferase (OGT). OGT does not appear to influence hmC activity, rather TET2 and TET3 promote OGT activity. TET2/3-OGT co-localize on chromatin at active promoters enriched for H3K4me3 and reduction of either TET2/3 or OGT activity results in a direct decrease in H3K4me3 and concomitant decreased transcription. Further, we show that Host Cell Factor 1 (HCF1), a component of the H3K4 methyltransferase SET1/COMPASS complex, is a specific GlcNAcylation target of TET2/3-OGT, and modification of HCF1 is important for the integrity of SET1/COMPASS. Additionally, we find both TET proteins and OGT activity promote binding of the SET1/COMPASS H3K4 methyltransferase, SETD1A, to chromatin. Finally, studies in Tet2 knockout mouse bone marrow tissue extend and support the data as decreases are observed of global GlcNAcylation and also of H3K4me3, notably at several key regulators of haematopoiesis. Together, our results unveil a step-wise model, involving TET-OGT interactions, promotion of GlcNAcylation, and influence on H3K4me3 via SET1/COMPASS, highlighting a novel means by which TETs may induce transcriptional activation. ChIP-Seq experiments were performed on Illumina HiScanSQ sequencer in wild-type HEK293T cells for H3K4me3 histone marks, O-GlcNAc and HCF1, for HT-TET2, HT-TET3 and HT-OGT in HEK293T cells overexpressing those three fusion proteins and in TET2 Kd HEK293T cells for H3K4me3 histone marks. ChIP-Seqs were also performed in mouse bone marrow tissues for H3K4me3 histone marks, O-GlcNAc, endogenous Tet2 and in Tet2 Ko bone marrow tissues for H3K4me3 histone marks.
2013-02-07 | E-GEOD-36620 | biostudies-arrayexpress
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2015-04-20 | E-GEOD-58514 | biostudies-arrayexpress
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2016-03-28 | E-GEOD-72735 | biostudies-arrayexpress
Project description:The largest and most diverse class of eukaryotic transcription factors contain Cys2-His2 zinc fingers (C2H2-ZFs), each of which typically binds a DNA nucleotide triplet within a larger binding site. Frequent recombination and diversification of their DNA-contacting residues suggests that these zinc fingers play a prevalent role in adaptive evolution. Very little is known about the function and evolution of the vast majority of C2H2-ZFs, including whether they even bind DNA. We determined in vivo binding sites of 39 human C2H2-ZF proteins, and correlated them with potential functions for these proteins. We expressed GFP-tagged C2H2-ZF proteins in stable transgenic HEK293 cells. Chromatin immunoprecipitation was performed as described before (Schmidt et al., Methods, 2009), and ChIP samples along with several control samples from different experimental batches were sequenced on Illumina HiSeq 2000. Reads were mapped to hg19 (GRCh37) assembly, and peaks were identified by MACS using an experiment-specific background that controls for various biases, such as the Sono-Seq effect as well as potential co-purification of targets of other (interacting) proteins.
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2016-07-05 | E-GEOD-63634 | biostudies-arrayexpress