Similar Datasets
Project description:Eukaryotic nuclei encase the genome and differentially package it for the various needs of distinct cell types. Tuning of genome structure and function is accomplished by chromatin binding proteins, which are responsive to cellular stress, determining the transcriptome and phenotype of the cell. We sought to investigate the connection between extracellular stress and chromatin structure to regulate cellular stiffness. We demonstrate that the linker histone H1.0, which compacts nucleosomes into higher order chromatin fibers, controls genome structure and cellular response to stress. Histone H1.0 has privileged expression in tension-responsive fibroblasts across tissue types in mouse and humans, and is necessary and sufficient to mount a myofibroblast phenotype in these cells. Loss of histone H1.0 prevents transforming growth factor beta (TGF-b)-induced fibroblast contraction, proliferation and migration in an isoform-specific manner via inhibition of a transcriptome targeting extracellular matrix molecules. Histone H1.0 is associated with local regulation of gene expression by chromatin fiber compaction and histone acetylation, rendering the nucleus and cell stiffer in response to cytokine stimulation. Knockdown of H1.0 decreased levels of HDAC1 and the chromatin reader BRD4, thereby preventing transcription of a fibrotic gene program. Transient depletion of histone H1.0 in vivo decompacts chromatin and prevents fibrosis in cardiac muscle, lung, and kidney, thereby linking chromatin structure with fibroblast phenotype in response to extracellular stress. Our work identifies an unexpected role of linker histones to sense and respond to cellular stress, directly coupling cellular tension, nuclear organization and gene transcription.
2024-02-28 | GSE215266 | GEO
Project description:Eukaryotic nuclei encase the genome and differentially package it for the various needs of distinct cell types. Tuning of genome structure and function is accomplished by chromatin binding proteins, which are responsive to cellular stress, determining the transcriptome and phenotype of the cell. We sought to investigate the connection between extracellular stress and chromatin structure to regulate cellular stiffness. We demonstrate that the linker histone H1.0, which compacts nucleosomes into higher order chromatin fibers, controls genome structure and cellular response to stress. Histone H1.0 has privileged expression in tension-responsive fibroblasts across tissue types in mouse and humans, and is necessary and sufficient to mount a myofibroblast phenotype in these cells. Loss of histone H1.0 prevents transforming growth factor beta (TGF-b)-induced fibroblast contraction, proliferation and migration in an isoform-specific manner via inhibition of a transcriptome targeting extracellular matrix molecules. Histone H1.0 is associated with local regulation of gene expression by chromatin fiber compaction and histone acetylation, rendering the nucleus and cell stiffer in response to cytokine stimulation. Knockdown of H1.0 decreased levels of HDAC1 and the chromatin reader BRD4, thereby preventing transcription of a fibrotic gene program. Transient depletion of histone H1.0 in vivo decompacts chromatin and prevents fibrosis in cardiac muscle, lung, and kidney, thereby linking chromatin structure with fibroblast phenotype in response to extracellular stress. Our work identifies an unexpected role of linker histones to sense and respond to cellular stress, directly coupling cellular tension, nuclear organization and gene transcription.
2024-02-28 | GSE215267 | GEO
Project description:This SuperSeries is composed of the SubSeries listed below.
2018-05-28 | GSE107533 | GEO
Project description:Tumors comprise functionally diverse subpopulations of cells with distinct proliferative potential. Here, we show that dynamic epigenetic states defined by the linker histone H1.0 determine which cells within a tumor can sustain the long-term cancer growth. Numerous cancer types exhibit high inter- and intratumor heterogeneity of H1.0, with H1.0 levels correlating with tumor differentiation status, patient survival, and, at the single-cell level, cancer stem cell markers. Silencing of H1.0 promotes maintenance of self-renewing cells by inducing derepression of megabase-sized gene domains harboring downstream effectors of oncogenic pathways. Self-renewing epigenetic states are not stable, and reexpression of H1.0 in subsets of tumor cells establishes transcriptional programs that restrict cancer cells' long-term proliferative potential and drive their differentiation. Our results uncover epigenetic determinants of tumor-maintaining cells.
| S-EPMC5131846 | biostudies-literature
Project description:Previous studies suggested that MeCP2 competes with linker histone H1, but this hypothesis has never been tested in vivo. Here, we performed chromatin immunoprecipitation followed by sequencing (ChIP-seq) of Flag-tagged-H1.0 in mouse forebrain excitatory neurons. Unexpectedly, Flag-H1.0 and MeCP2 occupied similar genomic regions and the Flag-H1.0 binding was not changed upon MeCP2 depletion. Furthermore, mild overexpression of H1.0 did not alter MeCP2 binding, suggesting that the functional binding of MeCP2 and H1.0 are largely independent.
| S-EPMC6099063 | biostudies-literature
Project description:Extracellular vesicles (EVs) are now recognized as a fundamental way for cell-to-cell horizontal transfer of properties, in both physiological and pathological conditions. Most of EV-mediated cross-talk among cells depend on the exchange of proteins, and nucleic acids, among which mRNAs, and non-coding RNAs such as different species of miRNAs. Cancer cells, in particular, use EVs to discard molecules which could be dangerous to them (for example differentiation-inducing proteins such as histone H1.0, or antitumor drugs), to transfer molecules which, after entering the surrounding cells, are able to transform their phenotype, and even to secrete factors, which allow escaping from immune surveillance. Herein we report that melanoma cells not only secrete EVs which contain a modified form of H1.0 histone, but also transport the corresponding mRNA. Given the already known role in tumorigenesis of some RNA binding proteins (RBPs), we also searched for proteins of this class in EVs. This study revealed the presence in A375 melanoma cells of at least three RBPs, with apparent MW of about 65, 45 and 38 kDa, which are able to bind H1.0 mRNA. Moreover, we purified one of these proteins, which by MALDI-TOF mass spectrometry was identified as the already known transcription factor MYEF2.
| S-EPMC5063456 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2012-12-12 | E-GEOD-26979 | biostudies-arrayexpress
Project description:Linker histone H1 (H1) is an abundant chromatin-binding protein that acts as an epigenetic regulator binding to nucleosomes and altering chromatin structures and dynamics. Nonetheless, the mechanistic details of its function remain poorly understood. Recent work suggest that the number and position of charged side chains on the globular domain (GD) of H1 influence chromatin structure and hence gene repression. Here, we solved the solution structure of the unbound GD of human H1.0, revealing that the structure is almost completely unperturbed by complex formation, except for a loop connecting two antiparallel β-strands. We further quantified the role of the many positive charges of the GD for its structure and conformational stability through the analysis of 11 charge variants. We find that modulating the number of charges has little effect on the structure, but the stability is affected, resulting in a difference in melting temperature of 26 K between GD of net charge +5 versus +13. This result suggests that the large number of positive charges on H1-GDs have evolved for function rather than structure and high stability. The stabilization of the GD upon binding to DNA can thus be expected to have a pronounced electrostatic component, a contribution that is amenable to modulation by posttranslational modifications, especially acetylation and phosphorylation.
| S-EPMC8927875 | biostudies-literature
Project description:The H1 linker histones are abundant chromatin-associated DNA-binding proteins. Recent evidence suggests that linker histones also may function through protein-protein interactions. To gain a better understanding of the scope of linker histone involvement in protein-protein interactions, we used a proteomics approach to identify H1-binding proteins in human nuclear extracts. Full-length H1.0 and H1.0 lacking its C-terminal domain (CTD) were used for protein pull-downs. A total of 107 candidate H1.0 binding proteins were identified by LC-MS/MS. About one-third of the H1.0-dependent interactions were mediated by the CTD, and two-thirds by the N-terminal domain-globular domain fragment. Many of the proteins pulled down by H1.0 were core splicing factors. Another group of H1-binding proteins functions in rRNA biogenesis. H1.0 also pulled down numerous ribosomal proteins and proteins involved in cellular transport. Strikingly, nearly all of the H1.0-binding proteins are found in the nucleolus. Quantitative biophysical studies with recombinant proteins confirmed that H1.0 directly binds to FACT and the splicing factors SF2/ASF and U2AF65. Our results demonstrate that H1.0 interacts with an extensive network of proteins that function in RNA metabolism in the nucleolus, and suggest that a new paradigm for linker histone action is in order.
| S-EPMC3627596 | biostudies-literature
Project description:The basic and intrinsically disordered C-terminal domain (CTD) of the linker histone (LH) is essential for chromatin compaction. However, its conformation upon nucleosome binding and its impact on chromatin organization remain unknown. Our mesoscale chromatin model with a flexible LH CTD captures a dynamic, salt-dependent condensation mechanism driven by charge neutralization between the LH and linker DNA. Namely, at low salt concentration, CTD condenses, but LH only interacts with the nucleosome and one linker DNA, resulting in a semi-open nucleosome configuration; at higher salt, LH interacts with the nucleosome and two linker DNAs, promoting stem formation and chromatin compaction. CTD charge reduction unfolds the domain and decondenses chromatin, a mechanism in consonance with reduced counterion screening in vitro and phosphorylated LH in vivo. Divalent ions counteract this decondensation effect by maintaining nucleosome stems and expelling the CTDs to the fiber exterior. Additionally, we explain that the CTD folding depends on the chromatin fiber size, and we show that the asymmetric structure of the LH globular head is responsible for the uneven interaction observed between the LH and the linker DNAs. All these mechanisms may impact epigenetic regulation and higher levels of chromatin folding.
| S-EPMC4081093 | biostudies-literature