Linker histones mediate sequence-specific regulation of chromosomal organization and H3K27me3 enrichment over genes and telomeric repeats
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE160414 | GEO | 2023/09/10
REPOSITORIES: GEO
Similar Datasets
Project description:Chromatin architecture relies on histone H1 whose central globular domain (GH1) sits on the nucleosome dyad and carboxy-terminal domain associates with linker DNA. We report that Arabidopsis H1 positively influences H3K27me3 chromatin enrichment over protein-coding genes but oppositely prevents its accumulation on telomeres and heterochromatic Interstitial Telomeric Repeats (ITRs). Contrasting with their neighboring heterochromatic environment, pericentromeric ITR regions remain highly compacted and are more prone to long-distance interactions with telomeres in H1 mutant plants. The switch from H1-rich to H3K27me3-rich ITR chromatin is further accompanied by an invasion of GH1-Myb Telomeric Repeat Binding protein 1 (TRB1), a structural component of telomeres capable to trigger H3K27me3 deposition over protein-coding genes displaying short telomeric motifs. This dual effect led us to propose a competition mechanism between H1 and TRB that prevents massive H3K27me3 deposition over large blocks of repeated motifs, thereby contributing to regulate H3K27me3 homeostasis over the genome.
2023-09-10 | GSE160413 | GEO
Project description:Chromatin architecture relies on histone H1 whose central globular domain (GH1) sits on the nucleosome dyad and carboxy-terminal domain associates with linker DNA. We report that Arabidopsis H1 positively influences H3K27me3 chromatin enrichment over protein-coding genes but oppositely prevents its accumulation on telomeres and heterochromatic Interstitial Telomeric Repeats (ITRs). Contrasting with their neighboring heterochromatic environment, pericentromeric ITR regions remain highly compacted and are more prone to long-distance interactions with telomeres in H1 mutant plants. The switch from H1-rich to H3K27me3-rich ITR chromatin is further accompanied by an invasion of GH1-Myb Telomeric Repeat Binding protein 1 (TRB1), a structural component of telomeres capable to trigger H3K27me3 deposition over protein-coding genes displaying short telomeric motifs. This dual effect led us to propose a competition mechanism between H1 and TRB that prevents massive H3K27me3 deposition over large blocks of repeated motifs, thereby contributing to regulate H3K27me3 homeostasis over the genome.
2023-09-10 | GSE160412 | GEO
Project description:Chromatin architecture relies on histone H1 whose central globular domain (GH1) sits on the nucleosome dyad and carboxy-terminal domain associates with linker DNA. We report that Arabidopsis H1 positively influences H3K27me3 chromatin enrichment over protein-coding genes but oppositely prevents its accumulation on telomeres and heterochromatic Interstitial Telomeric Repeats (ITRs). Contrasting with their neighboring heterochromatic environment, pericentromeric ITR regions remain highly compacted and are more prone to long-distance interactions with telomeres in H1 mutant plants. The switch from H1-rich to H3K27me3-rich ITR chromatin is further accompanied by an invasion of GH1-Myb Telomeric Repeat Binding protein 1 (TRB1), a structural component of telomeres capable to trigger H3K27me3 deposition over protein-coding genes displaying short telomeric motifs. This dual effect led us to propose a competition mechanism between H1 and TRB that prevents massive H3K27me3 deposition over large blocks of repeated motifs, thereby contributing to regulate H3K27me3 homeostasis over the genome.
2023-09-10 | GSE160411 | GEO
Project description:Chromatin architecture relies on histone H1 whose central globular domain (GH1) sits on the nucleosome dyad and carboxy-terminal domain associates with linker DNA. We report that Arabidopsis H1 positively influences H3K27me3 chromatin enrichment over protein-coding genes but oppositely prevents its accumulation on telomeres and heterochromatic Interstitial Telomeric Repeats (ITRs). Contrasting with their neighboring heterochromatic environment, pericentromeric ITR regions remain highly compacted and are more prone to long-distance interactions with telomeres in H1 mutant plants. The switch from H1-rich to H3K27me3-rich ITR chromatin is further accompanied by an invasion of GH1-Myb Telomeric Repeat Binding protein 1 (TRB1), a structural component of telomeres capable to trigger H3K27me3 deposition over protein-coding genes displaying short telomeric motifs. This dual effect led us to propose a competition mechanism between H1 and TRB that prevents massive H3K27me3 deposition over large blocks of repeated motifs, thereby contributing to regulate H3K27me3 homeostasis over the genome.
2023-09-10 | GSE160410 | GEO
Project description:Chromatin architecture relies on histone H1 whose central globular domain (GH1) sits on the nucleosome dyad and carboxy-terminal domain associates with linker DNA. We report that Arabidopsis H1 positively influences H3K27me3 chromatin enrichment over protein-coding genes but oppositely prevents its accumulation on telomeres and heterochromatic Interstitial Telomeric Repeats (ITRs). Contrasting with their neighboring heterochromatic environment, pericentromeric ITR regions remain highly compacted and are more prone to long-distance interactions with telomeres in H1 mutant plants. The switch from H1-rich to H3K27me3-rich ITR chromatin is further accompanied by an invasion of GH1-Myb Telomeric Repeat Binding protein 1 (TRB1), a structural component of telomeres capable to trigger H3K27me3 deposition over protein-coding genes displaying short telomeric motifs. This dual effect led us to propose a competition mechanism between H1 and TRB that prevents massive H3K27me3 deposition over large blocks of repeated motifs, thereby contributing to regulate H3K27me3 homeostasis over the genome.
2023-09-10 | GSE160408 | GEO
Project description:Chromatin architecture relies on histone H1 whose central globular domain (GH1) sits on the nucleosome dyad and carboxy-terminal domain associates with linker DNA. We report that Arabidopsis H1 positively influences H3K27me3 chromatin enrichment over protein-coding genes but oppositely prevents its accumulation on telomeres and heterochromatic Interstitial Telomeric Repeats (ITRs). Contrasting with their neighboring heterochromatic environment, pericentromeric ITR regions remain highly compacted and are more prone to long-distance interactions with telomeres in H1 mutant plants. The switch from H1-rich to H3K27me3-rich ITR chromatin is further accompanied by an invasion of GH1-Myb Telomeric Repeat Binding protein 1 (TRB1), a structural component of telomeres capable to trigger H3K27me3 deposition over protein-coding genes displaying short telomeric motifs. This dual effect led us to propose a competition mechanism between H1 and TRB that prevents massive H3K27me3 deposition over large blocks of repeated motifs, thereby contributing to regulate H3K27me3 homeostasis over the genome.
2023-09-10 | GSE190825 | GEO
Project description:Rat liver telomeric DNA is organised into nucleosomes characterised by a shorter and more homogeneous average nucleosomal repeat than bulk chromatin as shown by Makarov et al. (1). The latter authors were unable to detect the association of any linker histone with the telomeric DNA. We have confirmed these observations but show that in sharp contrast chicken erythrocyte telomeric DNA is organised into nucleosomes whose spacing length and heterogeneity are indistinguishable from those of bulk chromatin. We further show that chicken erythrocyte telomeric chromatin contains chromatosomes which are preferentially associated with histone H1 relative to histone H5. This contrasts with bulk chromatin where histone H5 is the more abundant species. This observation strongly suggests that telomeric DNA condensed into nucleosome core particles has a higher affinity for H1 than H5. We discuss the origin of the discrimination of the lysine rich histones in terms of DNA sequence preferences, telomere nucleosome preferences and particular constraints of the higher order chromatin structure of telomeres.
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Project description:Genomic DNA in eukaryotic cells is organized in supercoiled chromatin fibers, which undergo dynamic changes during such DNA metabolic processes as transcription or replication. Indeed, DNA-translocating enzymes like polymerases produce physical constraints in vivo. We used single-molecule micromanipulation by magnetic tweezers to study the response of chromatin to mechanical constraints in the same range as those encountered in vivo. We had previously shown that under positive torsional constraints, nucleosomes can undergo a reversible chiral transition toward a state of positive topology. We demonstrate here that chromatin fibers comprising linker histones present a torsional plasticity similar to that of naked nucleosome arrays. Chromatosomes can undergo a reversible chiral transition toward a state of positive torsion (reverse chromatosome) without loss of linker histones.
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