Ontology highlight
ABSTRACT:
PROVIDER: PRJNA844206 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Histones are the primary building blocks of chromatin in eukaryotes and many archaea. Bacteria are thought to rely on an orthogonal set of proteins to organize their chromosomes. Several bacterial genomes do, however, encode proteins with putative histone fold domains. Whether these proteins adopt a bona fide histone fold, assemble into higher order complexes that bind DNA, and play a central role in bacterial nucleoid physiology is not known. Here, we demonstrate that histones are major and essential building blocks of chromatin in the predatory bacterium Bdellovibrio bacteriovorus and the human pathogen Leptospira interrogans and likely important in several other bacterial clades. We determine the crystal structure of the B. bacteriovorus histone (Bd0055) dimer at 1.8Å resolution to reveal that histone fold topology, handshake dimer conformation, and the RD clamp motif are conserved between bacteria, archaea, and eukaryotes. However, ostensibly minor differences, including a shorter α2 helix, a less structured α3 helix, and a more acidic surface on one side of the dimer lead to a radically divergent DNA binding mode: instead of wrapping around the outer surface of a multi-subunit histone complex, DNA forms straight fibers, encased by a sheath of tightly packed Bd0055 dimers. Our results demonstrate that bacterial histones have evolved an atypical mode of DNA binding to become integral components of chromatin in distant parts of the bacterial kingdom
2023-08-16 | GSE220534 | GEO
Project description:Histones are the primary building blocks of chromatin in eukaryotes and many archaea. Bacteria are thought to rely on an orthogonal set of proteins to organize their chromosomes. Several bacterial genomes do, however, encode proteins with putative histone fold domains. Whether these proteins adopt a bona fide histone fold, assemble into higher order complexes that bind DNA, and play a central role in bacterial nucleoid physiology is not known. Here, we demonstrate that histones are major and essential building blocks of chromatin in the predatory bacterium Bdellovibrio bacteriovorus and the human pathogen Leptospira interrogans and likely important in several other bacterial clades. We determine the crystal structure of the B. bacteriovorus histone (Bd0055) dimer at 1.8Å resolution to reveal that histone fold topology, handshake dimer conformation, and the RD clamp motif are conserved between bacteria, archaea, and eukaryotes. However, ostensibly minor differences, including a shorter α2 helix, a less structured α3 helix, and a more acidic surface on one side of the dimer lead to a radically divergent DNA binding mode: instead of wrapping around the outer surface of a multi-subunit histone complex, DNA forms straight fibers, encased by a sheath of tightly packed Bd0055 dimers. Our results demonstrate that bacterial histones have evolved an atypical mode of DNA binding to become integral components of chromatin in distant parts of the bacterial kingdom.
2023-08-21 | PXD039405 | Pride
Project description:Topological domains are key architectural building blocks of chromosomes in complex genomes. Their functional importance and evolutionary dynamics are however not well defined. Here we performed comparative Hi-C in liver cells from four mammalian species, and characterized the conservation and divergence of chromosomal contact insulation and the resulting domain architectures within distantly related genomes. We show that the modular organization of chromosomes is robustly conserved in syntenic regions. This overall conservation is compatible with conservation of the binding landscape of the insulator protein CTCF. Specifically, conserved CTCF sites are co-localized with cohesin, enriched at strong topological domain borders and bind to DNA motifs with orientations that define the directionality of CTCF’s long-range interactions. Interestingly, CTCF binding sites which are divergent between species are strongly correlated with divergence of internal domain structure. This divergence is likely driven by local CTCF binding sequence changes, demonstrating how genome evolution can be linked directly with a continuous flux of local chromosome conformation changes. Conversely, we provide evidence that large-scale domains are harder to break and that they are reorganized during genome evolution as intact modules. Hi-C and 4C-seq experiments were conducted in primary liver cells obtained from mouse, rabbit, macaque and dog
2015-02-26 | E-GEOD-65126 | biostudies-arrayexpress
Project description:The three-dimensional organization of chromosomes can have a profound impact on their replication and expression. The chromosomes of higher eukaryotes possess discrete compartments that are characterized by differing transcriptional activities. Contrastingly, most bacterial chromosomes have simpler organization with local domains, the boundaries of which are influenced by gene expression. Numerous studies have revealed that the higher-order architectures of bacterial and eukaryotic chromosomes are dependent on the actions of Structural Maintenance of Chromosomes (SMC) superfamily protein complexes, in particular the near-universal condensin complex. Intriguingly, however, many archaea, including members of the genus Sulfolobus do not encode canonical condensin. We describe chromosome conformation capture experiments on Sulfolobus species. These reveal the presence of distinct domains along Sulfolobus chromosomes that undergo discrete and specific higher-order interactions, thus defining two compartment types. We observe causal linkages between compartment identity, gene expression and binding of a hitherto uncharacterized SMC superfamily protein that we term “coalescin”.
2019-09-19 | GSE128063 | GEO
Project description:To ensure proper gene regulation within constrained nuclear space, chromosomes facilitate access to transcribed regions, while compactly packaging all other information. Recent studies revealed that chromosomes are organized into megabase-scale domains that demarcate active and inactive genetic elements, suggesting that compartmentalization is important for genome function. Here we show that very specific long-range interactions are anchored by cohesin/CTCF sites, but not cohesin-only or CTCF-only sites, to form a hierarchy of chromosomal loops. These loops demarcate topological domains and form intricate internal structures within them. Post-mitotic nuclei deficient for functional cohesin exhibit global architectural changes associated with loss of cohesin/CTCF contacts and relaxation of topological domains. Transcriptional analysis shows that this cohesin-dependent perturbation of domain organization leads to widespread gene deregulation of both cohesin-bound and non-bound genes. Our data thereby support a role for cohesin in the global organization of domain structure and suggest that domains function to stabilize the transcriptional programs within them. Hi-C, ChIP-Seq and RNA-Seq experiments were conducted in mouse neural stem cells and mouse astrocytes
2013-12-11 | E-GEOD-49017 | biostudies-arrayexpress
Project description:To ensure proper gene regulation within constrained nuclear space, chromosomes facilitate access to transcribed regions, while compactly packaging all other information. Recent studies revealed that chromosomes are organized into megabase-scale domains that demarcate active and inactive genetic elements, suggesting that compartmentalization is important for genome function. Here we show that very specific long-range interactions are anchored by cohesin/CTCF sites, but not cohesin-only or CTCF-only sites, to form a hierarchy of chromosomal loops. These loops demarcate topological domains and form intricate internal structures within them. Post-mitotic nuclei deficient for functional cohesin exhibit global architectural changes associated with loss of cohesin/CTCF contacts and relaxation of topological domains. Transcriptional analysis shows that this cohesin-dependent perturbation of domain organization leads to widespread gene deregulation of both cohesin-bound and non-bound genes. Our data thereby support a role for cohesin in the global organization of domain structure and suggest that domains function to stabilize the transcriptional programs within them. Hi-C, ChIP-Seq and RNA-Seq experiments were conducted in mouse neural stem cells and mouse astrocytes
2013-12-11 | E-GEOD-48938 | biostudies-arrayexpress
Project description:To ensure proper gene regulation within constrained nuclear space, chromosomes facilitate access to transcribed regions, while compactly packaging all other information. Recent studies revealed that chromosomes are organized into megabase-scale domains that demarcate active and inactive genetic elements, suggesting that compartmentalization is important for genome function. Here we show that very specific long-range interactions are anchored by cohesin/CTCF sites, but not cohesin-only or CTCF-only sites, to form a hierarchy of chromosomal loops. These loops demarcate topological domains and form intricate internal structures within them. Post-mitotic nuclei deficient for functional cohesin exhibit global architectural changes associated with loss of cohesin/CTCF contacts and relaxation of topological domains. Transcriptional analysis shows that this cohesin-dependent perturbation of domain organization leads to widespread gene deregulation of both cohesin-bound and non-bound genes. Our data thereby support a role for cohesin in the global organization of domain structure and suggest that domains function to stabilize the transcriptional programs within them. Hi-C, ChIP-Seq and RNA-Seq experiments were conducted in mouse neural stem cells and mouse astrocytes
2013-12-11 | E-GEOD-48965 | biostudies-arrayexpress
Project description:Topological domains are key architectural building blocks of chromosomes in complex genomes. Their functional importance and evolutionary dynamics are however not well defined. Here we performed comparative Hi-C in liver cells from four mammalian species, and characterized the conservation and divergence of chromosomal contact insulation and the resulting domain architectures within distantly related genomes. We show that the modular organization of chromosomes is robustly conserved in syntenic regions. This overall conservation is compatible with conservation of the binding landscape of the insulator protein CTCF. Specifically, conserved CTCF sites are co-localized with cohesin, enriched at strong topological domain borders and bind to DNA motifs with orientations that define the directionality of CTCF’s long-range interactions. Interestingly, CTCF binding sites which are divergent between species are strongly correlated with divergence of internal domain structure. This divergence is likely driven by local CTCF binding sequence changes, demonstrating how genome evolution can be linked directly with a continuous flux of local chromosome conformation changes. Conversely, we provide evidence that large-scale domains are harder to break and that they are reorganized during genome evolution as intact modules.
2015-02-26 | GSE65126 | GEO
Project description:Transcription generates local topological and mechanical constraints along the DNA fiber, driving for instance the generation of supercoiled chromosomal domains in bacteria. However, the global impact of transcription-based regulation of chromosome organization remains elusive. Notably, the scale of genes and operons in bacteria remains well below the resolution of chromosomal contact maps generated using Hi-C (~ 5 - 10 kb), preventing to resolve the impact of transcription on genomic organization at the fine-scale. Here, we combined sub-kb Hi-C contact maps and chromosome engineering to visualize individual transcriptional units (TUs) while turning off transcription across the rest of the genome. We show that each TU forms a discrete, transcription-induced 3D domain (TIDs). These local structures impose mechanical and topological constraints on their neighboring sequences at larger scales, bringing them closer together and restricting their dynamics. These results show that the primary building blocks of bacteria chromosome folding consists of transcriptional domains that together shape the global genome structure.
2023-12-01 | GSE213028 | GEO
Project description:To ensure proper gene regulation within constrained nuclear space, chromosomes facilitate access to transcribed regions, while compactly packaging all other information. Recent studies revealed that chromosomes are organized into megabase-scale domains that demarcate active and inactive genetic elements, suggesting that compartmentalization is important for genome function. Here we show that very specific long-range interactions are anchored by cohesin/CTCF sites, but not cohesin-only or CTCF-only sites, to form a hierarchy of chromosomal loops. These loops demarcate topological domains and form intricate internal structures within them. Post-mitotic nuclei deficient for functional cohesin exhibit global architectural changes associated with loss of cohesin/CTCF contacts and relaxation of topological domains. Transcriptional analysis shows that this cohesin-dependent perturbation of domain organization leads to widespread gene deregulation of both cohesin-bound and non-bound genes. Our data thereby support a role for cohesin in the global organization of domain structure and suggest that domains function to stabilize the transcriptional programs within them.
2013-12-11 | GSE49017 | GEO