Similar Datasets
Project description:Tcrb locus V(D)J recombination is regulated by positioning at the nuclear periphery. Here, we used DamID to profile Tcrb locus interactions with the nuclear lamina at high resolution. We identified a lamina-associated domain (LAD) border composed of several CTCF-binding elements that segregates active non-LAD from inactive LAD regions of the locus. Deletion of the LAD border causes an enhancer-dependent spread of histone H3 lysine 27 acetylation from the active recombination center into recombination center-proximal LAD chromatin. This is associated with a disruption to nuclear lamina association, increased chromatin looping to the recombination center, and increased transcription and recombination of recombination center-proximal gene segments. Our results show that a LAD and LAD border are critical components of Tcrb locus gene regulation and suggest that LAD borders may generally function to constrain the activity of nearby enhancers.
| S-EPMC6287930 | biostudies-literature
Project description:Tcrb locus V(D)J recombination is regulated by positioning at the nuclear periphery. Here we used DamID to profile Tcrb locus interactions with the nuclear lamina at high-resolution. We identified a lamina-associated domain (LAD) border composed of several CTCF binding elements that segregates active non-LAD from inactive LAD regions of the locus. Deletion of the LAD border caused an enhancer-dependent spread of H3K27ac from the active recombination center into recombination center-proximal LAD chromatin. This was associated with a disruption to LAD organization, increased chromatin looping to the recombination center, and increased transcription and recombination of recombination center-proximal gene segments. Our results show that a Tcrb locus LAD and LAD border are critical components of Tcrb locus gene regulation and suggest that LAD borders may generally function to constrain the activity of nearby enhancers.
2018-10-22 | GSE116953 | GEO
Project description:Tcrb locus V(D)J recombination is regulated by positioning at the nuclear periphery. Here we used DamID to profile Tcrb locus interactions with the nuclear lamina at high-resolution. We identified a lamina-associated domain (LAD) border composed of several CTCF binding elements that segregates active non-LAD from inactive LAD regions of the locus. Deletion of the LAD border caused an enhancer-dependent spread of H3K27ac from the active recombination center into recombination center-proximal LAD chromatin. This was associated with a disruption to LAD organization, increased chromatin looping to the recombination center, and increased transcription and recombination of recombination center-proximal gene segments. Our results show that a Tcrb locus LAD and LAD border are critical components of Tcrb locus gene regulation and suggest that LAD borders may generally function to constrain the activity of nearby enhancers.
2018-10-22 | GSE115582 | GEO
Project description:A lamina-associated domain border governs nuclear lamina interactions, transcription and recombination of the Tcrb locus.
| PRJNA480688 | ENA
Project description:A lamina-associated domain border governs nuclear lamina interactions, transcription and recombination of the Tcrb locus [DamID]
| PRJNA480692 | ENA
Project description:A lamina-associated domain border governs nuclear lamina interactions, transcription and recombination of the Tcrb locus [ChIP-seq]
| PRJNA475536 | ENA
Project description:Allelic exclusion requires that the two alleles at antigen-receptor loci attempt to recombine variable (V), diversity (D), and joining (J) gene segments [V(D)J recombination] asynchronously in nuclei of developing lymphocytes. It previously was shown that T-cell receptor ? (Tcrb) alleles frequently and stochastically associate with the nuclear lamina and pericentromeric heterochromatin in CD4(-)CD8(-) thymocytes. Moreover, rearranged alleles were underrepresented at these locations. Here we used 3D immunofluorescence in situ hybridization to identify recently rearranged Tcrb alleles based on the accumulation of the DNA-repair protein 53BP1. We found that Tcrb alleles recombine asynchronously in double-negative thymocytes and that V(D)J recombination is suppressed on peripheral as compared with central Tcrb alleles. Moreover, the recombination events that did take place at the nuclear periphery preferentially occurred on Tcrb alleles that were partially dissociated from the nuclear lamina. To understand better the mechanism by which V(D)J recombination is suppressed at the nuclear periphery, we evaluated the subnuclear distribution of recombination-activating gene 2 (RAG2) protein. We found that RAG2 abundance was reduced at the nuclear periphery. Moreover, RAG2 was distributed differently from RNA polymerase II and histone H3K4 trimethylation. Our data suggest that the nuclear periphery suppresses V(D)J recombination, at least in part, by segregating Tcrb alleles from RAG proteins.
| S-EPMC3845165 | biostudies-literature
Project description:CTCF-mediated chromatin interactions influence organization and function of mammalian genome in diverse ways. We analyzed the interactions among CTCF binding sites (CBS) at the murine TCRb locus to discern the role of CTCF-mediated interactions in the regulation of transcription and VDJ recombination. Chromosome conformation capture analysis revealed thymocyte-specific long-range intrachromosomal interactions among various CBS across the locus that were relevant for defining the limit of the enhancer Eb-regulated recombination center (RC) and for facilitating the spatial proximity of TCRb variable (V) gene segments to the RC. Ectopic CTCF binding in the RC region, effected via genetic manipulation, altered CBS-directed chromatin loops, interfered with RC establishment, and reduced the spatial proximity of the RC with Trbv segments. Changes in chromatin loop organization by ectopic CTCF binding were relatively modest but influenced transcription and VDJ recombination dramatically. Besides revealing the importance of CTCF-mediated chromatin organization for TCRb regulation, the observed chromatin loops were consistent with the emerging idea that CBS orientations influence chromatin loop organization and underscored the importance of CBS orientations for defining chromatin architecture that supports VDJ recombination. Further, our study suggests that in addition to mediating long-range chromatin interactions, CTCF influences intricate configuration of chromatin loops that govern functional interactions between elements.
| S-EPMC5394274 | biostudies-literature
Project description:Proper genome functionality is underpinned by the non-random, spatial or ganisation of chromatin. At the periphery of the nucleus, the association of chr omatin with the nuclear lamina is thought to facilitate both structural organisa tion and regulation of gene expression. Except for a small number of individual loci, the regions of the human genome that locate at the nuclear lamina have not been identified. Here we used DamID to map the interaction sites of lamin B1 at high resolution in human fibroblasts. We show that almost half of the human gen ome preferentially associates with the nuclear lamina. Chromatin-lamina interact ions occur via sharply demarcated domains of up to several megabases in size, wh ich are bordered by similar sized domains that do not associate with the lamina. Lamina associated domains (LADs) are typified by low gene density and low gene expression levels. This is reflected by low levels of PolII binding and histone modification H3K4me2, in combination with enrichment of H3K27me3 (and H3K9?). A considerable subset of LADs is flanked by active promoters pointing outwards, or by the insulator protein CTCF, suggesting possible mechanisms of LAD confinemen t. Finally, we found that chromosome re-arrangements occur more frequently betwe en loci located either within or outside LADs. The identification of enormous, s harply defined stretches of the human genome that associate with the nuclear lam ina provides unprecedented insights into the 3D organisation of chromatin within the nucleus. Our results reveal the division of the human genome into periphera l and internal domains, which is echoed in genome functionality. Keywords: DamID
2008-05-07 | GSE8854 | GEO
Project description:Transcriptionally inactive genes are often positioned at the nuclear lamina (NL), as part of large lamina-associated domains (LADs). Activation of such genes is often accompanied by repositioning toward the nuclear interior. How this process works and how it impacts flanking chromosomal regions are poorly understood. We addressed these questions by systematic activation or inactivation of individual genes, followed by detailed genome-wide analysis of NL interactions, replication timing, and transcription patterns. Gene activation inside LADs typically causes NL detachment of the entire transcription unit, but rarely more than 50-100 kb of flanking DNA, even when multiple neighboring genes are activated. The degree of detachment depends on the expression level and the length of the activated gene. Loss of NL interactions coincides with a switch from late to early replication timing, but the latter can involve longer stretches of DNA. Inactivation of active genes can lead to increased NL contacts. These extensive datasets are a resource for the analysis of LAD rewiring by transcription and reveal a remarkable flexibility of interphase chromosomes.
| S-EPMC7073462 | biostudies-literature