Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA399075 | ENA |
REPOSITORIES: ENA
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Project description:Background: DNA methylation is a fundamental epigenetic modification which is involved in many biological systems such as differentiation and disease. We and other groups recently discovered that a part of transcription factors (TFs) plays a role for site-specificity determination of DNA demethylation in a binding site-directed manner, although number of reports for such TFs are limited. Results: Here, we develop a screening system to identify TFs which induce the binding site-directed DNA methylation changes. The system consists of ectopic expression of target TFs in model cells and the DNA methylome analysis followed by overrepresentation analysis of the corresponding TF binding motif at differentially methylated regions. Our system successfully identifies binding site-directed demethylation of SPI1 which is known to promote DNA demethylation in a binding-site directed manner. We extend our screening system to 15 master TFs which are involved in cellular differentiations, and identified 8 (RUNX3, GATA2, CEBPB, MAFB, NR4A2, MYOD1, CEBPA and TBX5) novel binding site-directed DNA demethylation inducing TFs. Gene ontology and specifically expressing tissue enrichment analysis revealed that those 8 TFs demethylate genome regions which are associated with corresponding biological roles, supporting performance of our system. We also describe characteristics of the binding site-directed DNA demethylation induced by those TFs; targeting highly methylated CpGs, local DNA demethylation, and overlap of demethylated regions between same family TFs. Conclusion: Thus, our results emphasize usefulness of the developed screening system for identification of TFs which induce DNA demethylation in a site-directed manner.
2017-11-29 | GSE102822 | GEO
Project description:Access of mammalian transcription factors (TFs) to regulatory regions, an essential event for transcription regulation, is hindered by chromatin compaction involving nucleosome wrapping, repressive histone modifications and DNA methylation. Moreover, methylation of TF binding sites (TBSs) affects TF binding affinity to these sites. Remarkably, a special class of TFs called pioneer transcription factors (PFs) can access nucleosomal DNA, leading to nucleosome remodelling and chromatin opening. However, whether PFs can bind to methylated sites and induce DNA demethylation is largely unknown. Here, we set up a highly parallelized approach to investigate PF ability to bind methylated DNA and induce demethylation. Our results indicate that the interdependence between DNA methylation and TF binding is more complex than previously thought, even within a select group of TFs that have a strong pioneering activity; while most PFs do not induce changes in DNA methylation at their binding sites, we identified PFs that can protect DNA from methylation and PFs that can induce DNA demethylation at methylated binding sites. We called the latter “super pioneer transcription factors” (SPFs), as they are seemingly able to overcome several types of repressive epigenetic marks. Importantly, while most SPFs induce TET-dependent active DNA demethylation, SOX2 binding leads to passive demethylation by inhibition of the maintenance methyltransferase DNMT1 during replication. This important finding suggests a novel mechanism allowing TFs to interfere with the epigenetic memory during DNA replication.
2021-03-18 | GSE144524 | GEO
Project description:RUNX1 (also known as AML1) is a key transcription factor for definitive hematopoietic stem cell development and following hematopoietic cell linage specifications, in which chromatin- or epigennome-mediated regulation by RUNX1, particularly regulation of DNA methylation status, is proposed to be involved in addition to its direct gene expression regulation. However, how RUNX1 regulates DNA methylation status and its role in the hematopoiesis remain to be elucidated. Here we first demonstrated that RUNX1 induces RUNX1 binding site directed DNA demethylation across the whole genome. HaloTag-based pull-down assay revealed associations of RUNX1 with active DNA demethylation related proteins such as TET, TDG or GADD45A, suggested that the RUNX1-mediated DNA demethylation is active DNA demethylation mechanism. Additional combinatorial overexpression of TET and TDG enlarged the RUNX1-mediated DNA demethylation, supporting what RUNX1-mediated DNA demethylation is active DNA demethylation. These results strongly suggested that RUNX1-mediated DNA demethylation is achieved by recruiting those proteins involved in active DNA demethylation. Finally, we found that the RUNX1-mediated demethylation predominately targets and activates hematopoietic genes whose promoter regions are demethylated during hematopoiesis. Collectively, our insight suggested that RUNX1-mediated binding site directed DNA demethylation is a novel mechanism of hematopoietic gene activation.
2017-08-10 | GSE60316 | GEO
Project description:The mechanisms whereby the crucial pluripotency transcription factor Oct4 regulates target gene expression are incompletely understood. Using an assay system based on partially differentiated embryonic stem cells, we show that Oct4 opposes accumulation of local H3K9me2, and subsequent Dnmt3a-mediated DNA methylation. Upon binding DNA, Oct4 recruits the histone lysine demethylase Jmjd1c. ChIP timecourse experiments identify a stepwise Oct4 mechanism involving Jmjd1c recruitment and H3K9me2 demethylation, transient FACT complex recruitment, and nucleosome depletion. Genome-wide and targeted ChIP confirms binding of newly-synthesized Oct4, together with Jmjd1c and FACT, to the Pou5f1 enhancer and a small number of other Oct4 targets, including the Nanog promoter. Histone demethylation is required for both FACT recruitment and H3 depletion. Jmjd1c is required to induce endogenous Oct4 expression and fully reprogram fibroblasts to pluripotency, indicating that the assay system identifies functional Oct4 cofactors. These findings indicate that Oct4 sequentially recruits activities that catalyze histone demethylation and depletion. Examination of transcription factor occupancy in cells with newly synthesized Oct4.
2015-01-23 | E-GEOD-65192 | biostudies-arrayexpress
Project description:Eukaryotic cells express a wide variety of endogenous small regulatory RNAs that function in the nucleus. We previously found that erroneous rRNAs induce the generation of antisense ribosomal siRNAs (risiRNAs) which silence the expression of rRNAs via the nuclear RNAi defective (Nrde) pathway. To further understand the biological roles and mechanisms of this class of small regulatory RNAs, we conducted forward genetic screening to identify factors involved in risiRNA generation in Caenorhabditis elegans. We found that risiRNAs accumulated in the RNA exosome mutants. risiRNAs directed a NRDE-dependent silencing of pre-rRNAs in the nucleolus. In the presence of risiRNAs, NRDE-2 accumulated in the nucleolus and colocalized with RNA polymerase I. risiRNAs inhibited the transcription elongation of RNA polymerase I by decreasing RNAP I occupancy downstream of the RNAi-targeted site. Meanwhile, exosomes mislocalized from the nucleolus to nucleoplasm in suppressor of siRNA (susi) mutants, in which erroneous rRNAs accumulated. These results established a novel model of rRNA surveillance by combining ribonuclease-mediated RNA degradation with small RNA-directed nucleolar RNAi system.
2021-01-20 | GSE165078 | GEO
Project description:DNA methylation is a major epigenetic modification for gene silencing and is dramatically altered spatiotemporally during cellular development. However, the roles of DNA methylation dynamics and regulation in cellular development remain unclear. The present analyses of DNA methylome dynamics during hematopoietic development suggest that DNA demethylation pre-defines the gene expression potential of terminal differentiation-specific genes at the progenitor cell stage and is regulated by lineage-specific transcription factors (TFs). Demethylation of majority of hypo-methylated CpGs in terminally differentiated cells occurs during the progenitor cell stage and is associated with rapid upregulation of terminal differentiation-specific genes. Accordingly, TF overrepresentation analyses indicated that lineage-specific TFs regulate DNA demethylation. The present experiments show that RUNX1 induces site-directed active DNA demethylation by recruiting DNA demethylation enzymes. Collectively, the present data indicate an integrated system of DNA methylation and gene expression during cellular development.
2017-08-10 | GSE85524 | GEO
Project description:DNA methylation is a major epigenetic modification for gene silencing and is dramatically altered spatiotemporally during cellular development. However, the roles of DNA methylation dynamics and regulation in cellular development remain unclear. The present analyses of DNA methylome dynamics during hematopoietic development suggest that DNA demethylation pre-defines the gene expression potential of terminal differentiation-specific genes at the progenitor cell stage and is regulated by lineage-specific transcription factors (TFs). Demethylation of majority of hypo-methylated CpGs in terminally differentiated cells occurs during the progenitor cell stage and is associated with rapid upregulation of terminal differentiation-specific genes. Accordingly, TF overrepresentation analyses indicated that lineage-specific TFs regulate DNA demethylation. The present experiments show that RUNX1 induces site-directed active DNA demethylation by recruiting DNA demethylation enzymes. Collectively, the present data indicate an integrated system of DNA methylation and gene expression during cellular development.
2017-08-10 | GSE85523 | GEO
Project description:Cells employ transcription-coupled repair (TCR) to eliminate transcription-blocking DNA lesions. DNA damage-induced binding of the TCR-specific repair factor CSB to RNA polymerase II (RNAPII) triggers RNAPII ubiquitylation at a single lysine (K1268) by the CRL4CSA ubiquitin ligase. How CRL4CSA is specifically directed toward the K1268 site is unknown. Here, we identify ELOF1 as the missing link that facilitates RNAPII ubiquitylation, a key signal for the assembly of downstream repair factors. This function requires its constitutive interaction with RNAPII close to the K1268 site, revealing ELOF1 as a specificity factor that interacts with and positions CRL4CSA for optimal RNAPII ubiquitylation. Drug-genetic interaction screening also reveals a CSB-independent compensatory pathway in which ELOF1 protects cells against DNA replication stress by preventing DNA damage-induced R-loops. Our study offers key insights into the molecular mechanisms of TCR and provides a genetic framework of the interplay between the transcriptional stress response and DNA replication.
2021-04-21 | PXD024051 | Pride
Project description:RUNX1-Mediated Binding Site Directed DNA Demethylation is a Novel Mechanism of Hematopoietic Gene Activation.
| PRJNA258014 | ENA
Project description:The mechanisms whereby the crucial pluripotency transcription factor Oct4 regulates target gene expression are incompletely understood. Using an assay system based on partially differentiated embryonic stem cells, we show that Oct4 opposes accumulation of local H3K9me2, and subsequent Dnmt3a-mediated DNA methylation. Upon binding DNA, Oct4 recruits the histone lysine demethylase Jmjd1c. ChIP timecourse experiments identify a stepwise Oct4 mechanism involving Jmjd1c recruitment and H3K9me2 demethylation, transient FACT complex recruitment, and nucleosome depletion. Genome-wide and targeted ChIP confirms binding of newly-synthesized Oct4, together with Jmjd1c and FACT, to the Pou5f1 enhancer and a small number of other Oct4 targets, including the Nanog promoter. Histone demethylation is required for both FACT recruitment and H3 depletion. Jmjd1c is required to induce endogenous Oct4 expression and fully reprogram fibroblasts to pluripotency, indicating that the assay system identifies functional Oct4 cofactors. These findings indicate that Oct4 sequentially recruits activities that catalyze histone demethylation and depletion.
2015-01-23 | GSE65192 | GEO