Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Histone H4 acetyl-methyllysine marks accessible chromatin that resists compaction

ABSTRACT: Regulatory DNA often remains accessible even under conditions of widespread chromatin compaction. Specific factors and histone modifications mark these regions and help maintain local accessibility. Here, we examine the genomic landscape of acetyl-methyllysine (Kacme), a recently discovered histone post-translational modification. Across multiple systems, Kacme is highly enriched at sites of accessible chromatin, including active promoters, enhancers, silencers, and CTCF-binding sites. We find that Kacme is selectively retained at loci that resist condensation during mitosis, marks XIST and escapee regions on the inactive X chromosome in female cells, and demarcates the boundaries of broad heterochromatin domains. Using the KDM6A/6B inhibitor GSK-J4 to elevate H3K27me3 levels, we show that Kacme-marked insulator elements block heterochromatin spreading and protect adjacent genes from transcriptional repression. Taken together, our findings define the chromatin features associated with Kacme and support a model in which Kacme safeguards chromatin accessibility, particularly at loci that remain active despite compaction and silencing pressures.

ORGANISM(S): Homo sapiens

PROVIDER: GSE326873 | GEO | 2026/04/22

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Histone H4 acetyl-methyllysine marks accessible chromatin that resists compaction

Project description:Histone H4 acetyl-methyllysine marks accessible chromatin that resists compaction

| PRJNA1447509 | ENA

A nowhere-to-hide mechanism ensures complete piRNA-directed LINE1 methylation

Project description:The mouse PIWI-interacting RNA (piRNA) pathway provides anti-transposon immunity to the developing male germline by directing transposon DNA methylation. The first step in this process is the recruitment of SPOCD1 to young LINE1 loci 1 followed in the second step by piRNA-mediated tethering of the PIWI protein MIWI2 (PIWIL4) to the nascent transposon transcript. To protect the germline, the piRNA pathway needs to methylate all active transposon copies but how this is achieved remains unknown. Here, we show that nuclear piRNA and de novo methylation factors are all euchromatic. We find that SPOCD1 directly interacts with the nuclear pore component TPR, which forms heterochromatin exclusion zones adjacent to nuclear pores. In foetal gonocytes undergoing piRNA-directed DNA methylation, TPR is found both at the nuclear periphery but also abundantly throughout the nucleoplasm. We found that the SPOCD1-TPR interaction is required for complete non-stochastic piRNA-directed LINE1 methylation. The loss of the SPOCD1-TPR interaction results in a fraction of SPOCD1 and other chromatin-bound piRNA factors to relocalise to constitutive heterochromatin where they are no longer accessible to MIWI2 and the de novo methylation machinery. We propose that TPR-mediated heterochromatin exclusion provides a nowhere-to-hide mechanism for SPOCD1-bound LINE1 loci throughout the nucleoplasm. In summary, the piRNA pathway has co-opted TPR to guarantee LINE1s are euchromatic and accessible to the piRNA and de novo methylation machineries.

2025-11-11 | PXD060850 | Pride

A nowhere-to-hide mechanism ensures complete piRNA-directed LINE1 methylation

2025-11-11 | PXD060851 | Pride

HMGB2 orchestrates the chromatin landscape of senescence-associated secretory phenotype gene loci.

Project description:Cellular senescence is a stable cell growth arrest that is characterized by silencing of proliferation-promoting genes through compaction of individual chromosomes into senescence-associated heterochromatin foci (SAHF). Paradoxically, senescence is also accompanied by increased expression of certain secreted factors such as cytokines and chemokines, known as senescence-associated secretory phenotype (SASP). How SASP genes are excluded from SAHF-mediated global gene silencing remains unclear. Here we report that HMGB2 orchestrates the chromatin landscape of SASP gene loci. HMGB2 preferentially localizes to SASP gene loci during senescence. Loss of HMGB2 during senescence blunts SASP gene expression by allowing for spreading of repressive heterochromatin into SASP gene loci. This correlated with incorporation of SASP gene loci into SAHF. Our results establish HMGB2 as a novel master regulator that orchestrates SASP through preventing heterochromatin spreading to allow for exclusion of SASP gene loci from a global heterochromatin environment during senescence.

2016-10-11 | GSE85057 | GEO

Dynamics of de novo heterochromatin assembly and disassembly at replication forks ensures fork stability

Project description:Chromatin is dynamically reorganized when DNA replication forks are challenged. However, the process of epigenetic reorganization and its implication for fork stability is poorly understood. Here, we discover a checkpoint regulated cascade of chromatin signaling that activates 5 the histone methyltransferase EHMT2/G9a to catalyze heterochromatin assembly at stressed replication forks. Using biochemical and single molecule chromatin fiber approaches, we show that G9a together with SUV39h1 induces chromatin compaction by accumulating the repressive modifications, H3K9me1/me2/me3, in the vicinity of stressed replication forks. This closed conformation is also favored by the G9a-dependent exclusion of the H3K9-demethylase 10 JMJD1A/KDM3A, which facilitates heterochromatin disassembly upon fork restart. Untimely heterochromatin disassembly from stressed forks by KDM3A enables PRIMPOL access, triggering ssDNA gap formation and sensitizing cells towards chemotherapeutic drugs. These findings may help explaining chemotherapy resistance and poor prognosis observed in cancer patients displaying elevated level of G9a/H3K9me3.

2023-05-12 | PXD041742 | Pride

Ki-67 organises heterochromatin during cell proliferation

Project description:Antigen Ki-67 is a nuclear protein expressed in proliferating mammalian cells. It is widely used in cancer histopathology but its functions remain unclear. Here, we show that Ki-67 controls heterochromatin organisation. Altering Ki-67 expression levels did not significantly affect cell proliferation in vivo. Ki-67 mutant mice developed normally and cells lacking Ki-67 proliferated efficiently. Conversely, upregulation of Ki-67 expression in differentiated tissues did not inhibit cell cycle arrest. Ki-67 interactors included proteins involved in nucleolar processes and chromatin regulators. Ki-67 depletion disrupted nucleologenesis but did not inhibit pre-rRNA processing. In contrast, it altered gene expression. Ki-67 silencing also had wide-ranging effects on chromatin organisation, disrupting heterochromatin compaction and long-range genomic interactions. Trimethylation of histone H3K9 and H4K20 at heterochromatin was strongly reduced. Overexpression of human or Xenopus Ki-67 induced ectopic heterochromatin formation. Altogether, our results suggest that Ki-67 expression in proliferating cells spatially organises heterochromatin, thereby controlling gene expression.

2018-10-26 | PXD003551 | Pride

Basis for Lineage-Determining Pioneer Factors Targeting Distinct Repressed Chromatin States

Project description:Pioneer transcription factors target compact, transcriptionally silent chromatin, thereby enabling gene activation in development, regeneration, and cell reprogramming. However, silent chromatin is heterogenous, varying in nucleosome mobility, nucleosome compaction, and repressive histone modifications, and how pioneer factors may overcome these different chromatin barriers is unknown. We systematically compared the chromatin targeting of 13 embryonic transcription factors and found that the DNA binding domain (DBD) type predicts whether a pioneer factor targets low-turnover nucleosomes in compact chromatin, dynamic nucleosomes in compact chromatin, or function as non-pioneer factors targeting accessible chromatin. By contrast, non-DBD domains enable targeting of repressed chromatin marked by H3K9me3 or H3K27me3. Fusions of different non-DBD segments of heterochromatin-targeting pioneer factors onto SOX2 can expand binding of Sox2 target motifs, including within heterochromatin, and improve cellular reprogramming. Our study unveils how different forms of silent chromatin are coordinately targeted by lineage-specifying factors.

2025-12-03 | GSE299017 | GEO

Heterochromatin rewiring and domain disruption-mediated chromatin compaction during erythropoiesis

Project description:Heterochromatin rewiring and domain disruption-mediated chromatin compaction during erythropoiesis

| PRJNA763785 | ENA

Heterochromatin rewiring and domain disruption-mediated chromatin compaction during erythropoiesis

Project description:Heterochromatin rewiring and domain disruption-mediated chromatin compaction during erythropoiesis

| PRJNA762583 | ENA

Homo sapiens

Project description:CTCF demarcates chromatin domains

| PRJNA110881 | ENA