Similar Datasets
Project description:The multivalent binding of CTCF to a variety of DNA sequences is thought to underlie its ability to mediate a large repertoire of cellular functions. CTCF is a 11 zinc-finger (ZF) protein that is anchored to a majority of its target sites via binding to a 20 base-pair core DNA sequence. Yet the diversity of CTCF binding sites (CBS) has not fully been characterized. Here we assessed CTCF occupancy in cultured mouse cortical neurons as a function of neuronal activity and observed that ~ 22 % of CBS lack the consensus CTCF motif. We report that sequence diversity at most of these atypical CBS is not random but involves degeneracy at specific nucleotide positions within the core CTCF position weight matrix (PWM) that likely affect the binding of ZFs 6 and 7. Surprisingly, degeneracy at the same nucleotides not only define most atypical CBS, but also CBS within most gene promoters, and CBS that are dynamically altered following neuronal stimulation, revealing how atypical CTCF binding could affect gene activity. Dynamic CBS across neural differentiation and neuronal stimulation are found both within and outside loop anchors and TADs, indicating that dynamic CBS could regulate gene activity independently of loop anchoring. Finally, we identified a second mode of atypical CTCF binding that defines most tissue-specific CBS. Unlike other atypical CBS, tissue-specific CBS largely bind sequences unrelated to the core CTCF motif and are enriched within the bodies of tissue-specific genes. Overall, these results indicate how CTCF binding at atypical CBS could allow it to dynamically regulate gene activity patterns during differentiation, development, and in response to environmental cues.
2023-08-30 | GSE235971 | GEO
Project description:The multivalent binding of CTCF to a variety of DNA sequences is thought to underlie its ability to mediate a large repertoire of cellular functions. CTCF is a 11 zinc-finger (ZF) protein that is anchored to a majority of its target sites via binding to a 20 base-pair core DNA sequence. Yet the diversity of CTCF binding sites (CBS) has not fully been characterized. Here we assessed CTCF occupancy in cultured mouse cortical neurons as a function of neuronal activity and observed that ~ 22 % of CBS lack the consensus CTCF motif. We report that sequence diversity at most of these atypical CBS is not random but involves degeneracy at specific nucleotide positions within the core CTCF position weight matrix (PWM) that likely affect the binding of ZFs 6 and 7. Surprisingly, degeneracy at the same nucleotides not only define most atypical CBS, but also CBS within most gene promoters, and CBS that are dynamically altered following neuronal stimulation, revealing how atypical CTCF binding could affect gene activity. Dynamic CBS across neural differentiation and neuronal stimulation are found both within and outside loop anchors and TADs, indicating that dynamic CBS could regulate gene activity independently of loop anchoring. Finally, we identified a second mode of atypical CTCF binding that defines most tissue-specific CBS. Unlike other atypical CBS, tissue-specific CBS largely bind sequences unrelated to the core CTCF motif and are enriched within the bodies of tissue-specific genes. Overall, these results indicate how CTCF binding at atypical CBS could allow it to dynamically regulate gene activity patterns during differentiation, development, and in response to environmental cues.
2023-08-30 | GSE235970 | GEO
Project description:Atypical modes of CTCF binding facilitate tissue-specific and neuronal activity-dependent gene expression states.
| PRJNA988096 | ENA
Project description:Atypical modes of CTCF binding facilitate tissue-specific and neuronal activity-dependent gene expression states [CTCF_ChIP-seq]
| PRJNA988104 | ENA
Project description:Atypical modes of CTCF binding facilitate tissue-specific and neuronal activity-dependent gene expression states [SMC1_ChIP-seq]
| PRJNA988103 | ENA
Project description:Binding sites of the chromatin regulator protein CTCF function as important landmarks in the human genome. The recently characterized CTCF-binding sites at LINE-1 repeats depend on another repeat-regulatory protein CGGBP1. These CGGBP1-dependent CTCF-binding sites serve as potential barrier elements for epigenetic marks such as H3K9me3. Such CTCF-binding sites are associated with asymmetric H3K9me3 levels as well as RNA levels in their flanks. The functions of these CGGBP1-dependent CTCF-binding sites remain unknown. By performing targeted studies on candidate CGGBP1-dependent CTCF-binding sites cloned in an SV40 promoter-enhancer episomal system we show that these regions act as inhibitors of ectopic transcription from the SV40 promoter. CGGBP1-dependent CTCF-binding sites that recapitulate their genomic function of loss of CTCF binding upon CGGBP1 depletion and H3K9me3 asymmetry in immediate flanks are also the ones that show the strongest inhibition of ectopic transcription. By performing a series of strand-specific reverse transcription PCRs we demonstrate that this ectopic transcription results in the synthesis of RNA from the SV40 promoter in a direction opposite to the downstream reporter gene in a strand-specific manner. The unleashing of the bidirectionality of the SV40 promoter activity and a breach of the transcription barrier seems to depend on depletion of CGGBP1 and loss of CTCF binding proximal to the SV40 promoter. RNA-sequencing reveals that CGGBP1-regulated CTCF-binding sites act as barriers to transcription at multiple locations genome-wide. These findings suggest a role of CGGBP1-dependent binding sites in restricting ectopic transcription.
| S-EPMC8794514 | biostudies-literature
Project description:The weaning transition in calves is characterized by major structural changes such as an increase in the rumen capacity and surface area due to diet changes. Studies evaluating rumen development in calves are vital to identify genetic mechanisms affected by weaning. This study aimed to provide a genome-wide characterization of CTCF-binding sites and differentially CTCF-binding sites (DCBS) in rumen tissue during the weaning transition of four Holstein calves to uncover regulatory elements in rumen epithelial tissue using ChIP-seq. Our study generated 67,280 CTCF peaks for the before weaning (BW) and 39,891 for after weaning (AW). Then, 7401 DCBS were identified for the AW vs. BW comparison representing 0.15% of the cattle genome, comprising ~54% of induced DCBS and ~46% of repressed DCBS. Most of the induced and repressed DCBS were in distal intergenic regions, showing a potential role as insulators. Gene ontology enrichment revealed many shared GO terms for the induced and the repressed DCBS, mainly related to cellular migration, proliferation, growth, differentiation, cellular adhesion, digestive tract morphogenesis, and response to TGFβ. In addition, shared KEGG pathways were obtained for adherens junction and focal adhesion. Interestingly, other relevant KEGG pathways were observed for the induced DCBS like gastric acid secretion, salivary secretion, bacterial invasion of epithelial cells, apelin signaling, and mucin-type O-glycan biosynthesis. IPA analysis further revealed pathways with potential roles in rumen development during weaning, including TGFβ, Integrin-linked kinase, and Integrin signaling. When DCBS were further integrated with RNA-seq data, 36 putative target genes were identified for the repressed DCBS, including KRT84, COL9A2, MATN3, TSPAN1, and AJM1. This study successfully identified DCBS in cattle rumen tissue after weaning on a genome-wide scale and revealed several candidate target genes that may have a role in rumen development, such as TGFβ, integrins, keratins, and SMADs. The information generated in this preliminary study provides new insights into bovine genome regulation and chromatin landscape.
| S-EPMC9408924 | biostudies-literature
Project description:The molecular mechanism of long-term memory has been extensively studied in the context of the hippocampus-dependent recent memory examined within several days. However, months-old remote memory maintained in the cortex for long-term has not been investigated much at the molecular level yet. Various epigenetic mechanisms are known to be important for long-term memory, but how the 3D chromatin architecture and its regulator molecules contribute to neuronal plasticity and systems consolidation is still largely unknown. CCCTC-binding factor (CTCF) is an 11-zinc finger protein well known for its role as a genome architecture molecule. Male conditional knock-out mice in which CTCF is lost in excitatory neurons during adulthood showed normal recent memory in the contextual fear conditioning and spatial water maze tasks. However, they showed remarkable impairments in remote memory in both tasks. Underlying the remote memory-specific phenotypes, we observed that female CTCF conditional knock-out mice exhibit disrupted cortical LTP, but not hippocampal LTP. Similarly, we observed that CTCF deletion in inhibitory neurons caused partial impairment of remote memory. Through RNA sequencing, we observed that CTCF knockdown in cortical neuron culture caused altered expression of genes that are highly involved in cell adhesion, synaptic plasticity, and memory. These results suggest that remote memory storage in the cortex requires CTCF-mediated gene regulation in neurons, whereas recent memory formation in the hippocampus does not.SIGNIFICANCE STATEMENT CCCTC-binding factor (CTCF) is a well-known 3D genome architectural protein that regulates gene expression. Here, we use two different CTCF conditional knock-out mouse lines and reveal, for the first time, that CTCF is critically involved in the regulation of remote memory. We also show that CTCF is necessary for appropriate expression of genes, many of which we found to be involved in the learning- and memory-related processes. Our study provides behavioral and physiological evidence for the involvement of CTCF-mediated gene regulation in the remote long-term memory and elucidates our understanding of systems consolidation mechanisms.
| S-EPMC6705941 | biostudies-literature
Project description:The CCCTC-binding factor (CTCF) works together with the cohesin complex to drive the formation of chromatin loops and topologically associating domains, but its role in gene regulation has not been fully defined. Here, we investigated the effects of acute CTCF loss on chromatin architecture and transcriptional programs in mouse embryonic stem cells undergoing differentiation to neural precursor cells. We identified CTCF-dependent enhancer-promoter contacts genome-wide and found that they disproportionately affect genes that are bound by CTCF at the promoter and are dependent on long-distance enhancers. Disruption of promoter-proximal CTCF binding reduced both long-range enhancer-promoter contacts and transcription, which were restored by artificial tethering of CTCF to the promoter. Promoter-proximal CTCF binding is correlated with the transcription of over 2,000 genes across a diverse set of adult tissues. Taken together, the results of our study show that CTCF binding to promoters may promote long-distance enhancer-dependent transcription at specific genes in diverse cell types.
| S-EPMC7913465 | biostudies-literature
Project description:Associating genetic variation with quantitative measures of gene regulation offers a way to bridge the gap between genotype and complex phenotypes. In order to identify quantitative trait loci (QTLs) that influence the binding of a transcription factor in humans, we measured binding of the multifunctional transcription and chromatin factor CTCF in 51 HapMap cell lines. We identified thousands of QTLs in which genotype differences were associated with differences in CTCF binding strength, hundreds of them confirmed by directly observable allele-specific binding bias. The majority of QTLs were either within 1 kb of the CTCF binding motif, or in linkage disequilibrium with a variant within 1 kb of the motif. On the X chromosome we observed three classes of binding sites: a minority class bound only to the active copy of the X chromosome, the majority class bound to both the active and inactive X, and a small set of female-specific CTCF sites associated with two non-coding RNA genes. In sum, our data reveal extensive genetic effects on CTCF binding, both direct and indirect, and identify a diversity of patterns of CTCF binding on the X chromosome.
| S-EPMC4238955 | biostudies-literature