CTCF: a Swiss-army knife for genome organization and transcription regulation

2019 ◽  
Vol 63 (1) ◽  
pp. 157-165 ◽  
Author(s):  
Luca Braccioli ◽  
Elzo de Wit
Keyword(s):  
Transcription Regulation ◽  
Genome Organization ◽  
Rna Splicing ◽  
Ctcf Binding ◽  
Loop Formation ◽  
Disease Etiology ◽  
3D Genome ◽  
Dna Loop ◽  
Binding Factor ◽  
Key Aspects

Abstract Orchestrating vertebrate genomes require a complex interplay between the linear composition of the genome and its 3D organization inside the nucleus. This requires the function of specialized proteins, able to tune various aspects of genome organization and gene regulation. The CCCTC-binding factor (CTCF) is a DNA binding factor capable of regulating not only the 3D genome organization, but also key aspects of gene expression, including transcription activation and repression, RNA splicing, and enhancer/promoter insulation. A growing body of evidence proposes that CTCF, together with cohesin contributes to DNA loop formation and 3D genome organization. CTCF binding sites are mutation hotspots in cancer, while mutations in CTCF itself lead to intellectual disabilities, emphasizing its importance in disease etiology. In this review we cover various aspects of CTCF function, revealing the polyvalence of this factor as a highly diversified tool for vertebrate genome organization and transcription regulation.

scholarly journals Identification and analysis of consensus RNA motifs binding to the genome regulator CTCF

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Shuzhen Kuang ◽  
Liangjiang Wang
Keyword(s):  
Genome Organization ◽  
Molecular Mechanisms ◽  
Short Term Memory ◽  
Consensus Sequence ◽  
Ctcf Binding ◽  
Specific Sequence ◽  
3D Genome ◽  
Rna Transcripts ◽  
Memory Network ◽  
Rna Motif

Abstract CCCTC-binding factor (CTCF) is a key regulator of 3D genome organization and gene expression. Recent studies suggest that RNA transcripts, mostly long non-coding RNAs (lncRNAs), can serve as locus-specific factors to bind and recruit CTCF to the chromatin. However, it remains unclear whether specific sequence patterns are shared by the CTCF-binding RNA sites, and no RNA motif has been reported so far for CTCF binding. In this study, we have developed DeepLncCTCF, a new deep learning model based on a convolutional neural network and a bidirectional long short-term memory network, to discover the RNA recognition patterns of CTCF and identify candidate lncRNAs binding to CTCF. When evaluated on two different datasets, human U2OS dataset and mouse ESC dataset, DeepLncCTCF was shown to be able to accurately predict CTCF-binding RNA sites from nucleotide sequence. By examining the sequence features learned by DeepLncCTCF, we discovered a novel RNA motif with the consensus sequence, AGAUNGGA, for potential CTCF binding in humans. Furthermore, the applicability of DeepLncCTCF was demonstrated by identifying nearly 5000 candidate lncRNAs that might bind to CTCF in the nucleus. Our results provide useful information for understanding the molecular mechanisms of CTCF function in 3D genome organization.

scholarly journals Determining cellular CTCF and cohesin abundances to constrain 3D genome models

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Claudia Cattoglio ◽  
Iryna Pustova ◽  
Nike Walther ◽  
Jaclyn J Ho ◽  
Merle Hantsche-Grininger ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Site Occupancy ◽  
Cellular Protein ◽  
Protein Quantification ◽  
Ctcf Binding ◽  
Ctcf Binding Site ◽  
3D Genome ◽  
Quantitative Measurements ◽  
Dna Loop ◽  
Predictive Understanding

Achieving a quantitative and predictive understanding of 3D genome architecture remains a major challenge, as it requires quantitative measurements of the key proteins involved. Here, we report the quantification of CTCF and cohesin, two causal regulators of topologically associating domains (TADs) in mammalian cells. Extending our previous imaging studies (Hansen et al., 2017), we estimate bounds on the density of putatively DNA loop-extruding cohesin complexes and CTCF binding site occupancy. Furthermore, co-immunoprecipitation studies of an endogenously tagged subunit (Rad21) suggest the presence of cohesin dimers and/or oligomers. Finally, based on our cell lines with accurately measured protein abundances, we report a method to conveniently determine the number of molecules of any Halo-tagged protein in the cell. We anticipate that our results and the established tool for measuring cellular protein abundances will advance a more quantitative understanding of 3D genome organization, and facilitate protein quantification, key to comprehend diverse biological processes.

scholarly journals In silico prediction of high-resolution Hi-C interaction matrices

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shilu Zhang ◽  
Deborah Chasman ◽  
Sara Knaack ◽  
Sushmita Roy
Keyword(s):  
High Resolution ◽  
Genome Organization ◽  
Three Dimensional ◽  
Predictive Performance ◽  
Computational Prediction ◽  
3D Genome ◽  
Genome Wide ◽  
Binding Factor ◽  
Sequence Elements ◽  
Individual Locus

AbstractThe three-dimensional (3D) organization of the genome plays an important role in gene regulation bringing distal sequence elements in 3D proximity to genes hundreds of kilobases away. Hi-C is a powerful genome-wide technique to study 3D genome organization. Owing to experimental costs, high resolution Hi-C datasets are limited to a few cell lines. Computational prediction of Hi-C counts can offer a scalable and inexpensive approach to examine 3D genome organization across multiple cellular contexts. Here we present HiC-Reg, an approach to predict contact counts from one-dimensional regulatory signals. HiC-Reg predictions identify topologically associating domains and significant interactions that are enriched for CCCTC-binding factor (CTCF) bidirectional motifs and interactions identified from complementary sources. CTCF and chromatin marks, especially repressive and elongation marks, are most important for HiC-Reg’s predictive performance. Taken together, HiC-Reg provides a powerful framework to generate high-resolution profiles of contact counts that can be used to study individual locus level interactions and higher-order organizational units of the genome.

scholarly journals Environmental enrichment induces epigenomic and genome organization changes relevant for cognitive function

2021 ◽  
Author(s):  
Sergio Espeso-Gil ◽  
Aliaksei Holik ◽  
Sarah Bonnin ◽  
Shalu Jhanwar ◽  
Sandhya Chandrasekaran ◽  
...  
Keyword(s):  
Cognitive Function ◽  
Genome Organization ◽  
Environmental Enrichment ◽  
Neuronal Development ◽  
Chromatin Accessibility ◽  
Ctcf Binding ◽  
List Type ◽  
Dependent Manner ◽  
3D Genome ◽  
Induced Changes

SummaryIn early development, the environment triggers mnemonic epigenomic programs resulting in memory and learning experiences to confer cognitive phenotypes into adulthood. To uncover how environmental stimulation impacts the epigenome and genome organization, we used the paradigm of environmental enrichment (EE) in young mice constantly receiving novel stimulation. We profiled epigenome and chromatin architecture in whole cortex and sorted neurons by deep-sequencing techniques. Specifically, we studied chromatin accessibility, gene and protein regulation, and 3D genome conformation, combined with predicted enhancer and chromatin interactions. We identified increased chromatin accessibility, transcription factor binding including CTCF-mediated insulation, differential occupancy of H3K36me3 and H3K79me2, and changes in transcriptional programs required for neuronal development. EE stimuli led to local genome re-organization by inducing increased contacts between chromosomes 7 and 17 (inter-chromosomal). Our findings support the notion that EE-induced learning and memory processes are directly associated with the epigenome and genome organization.Highlights-Environmental enrichment (EE) alters chromatin conformation, CTCF binding, and spatially 3D genome changes, thereby regulating cognitive function during the first steps of life after birth.-Transcription-associated gene body marks H3K79me2 and H3K36me3 are differently influenced by EE in cortical brain cells and binding is exacerbated upon stimulation in an age-dependent manner.-EE-induced changes of 3D genome organization increase inter-chromosomal interactions of genes associated with synaptic transmission and AMPA receptor genes on chromosomes 7 and 17.

scholarly journals Determining cellular CTCF and cohesin abundances to constrain 3D genome models

2018 ◽  
Author(s):  
Claudia Cattoglio ◽  
Iryna Pustova ◽  
Nike Walther ◽  
Jaclyn J. Ho ◽  
Merle Hantsche-Grininger ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Site Occupancy ◽  
Cellular Protein ◽  
Protein Quantification ◽  
Ctcf Binding ◽  
Ctcf Binding Site ◽  
3D Genome ◽  
Quantitative Measurements ◽  
Dna Loop ◽  
Predictive Understanding

Achieving a quantitative and predictive understanding of 3D genome architecture remains a major challenge, as it requires quantitative measurements of the key proteins involved. Here we report the quantification of CTCF and cohesin, two causal regulators of topologically associating domains (TADs) in mammalian cells. Extending our previous imaging studies (Hansen et al., 2017), we estimate bounds on the density of putatively DNA loop-extruding cohesin complexes and CTCF binding site occupancy. Furthermore, co-immunoprecipitation studies of an endogenously tagged subunit (Rad21) suggest the presence of cohesin dimers and/or oligomers. Finally, based on our cell lines with accurately measured protein abundances, we report a method to conveniently determine the number of molecules of any Halo-tagged protein in the cell. We anticipate that our results and the established tool for measuring cellular protein abundances will advance a more quantitative understanding of 3D genome organization, and facilitate protein quantification, key to comprehend diverse biological processes.

scholarly journals Impact of 3D genome organization, guided by cohesin and CTCF looping, on sex-biased chromatin interactions and gene expression in mouse liver

2020 ◽  
Author(s):  
Bryan J Matthews ◽  
David J Waxman
Keyword(s):  
Gene Expression ◽  
Sex Differences ◽  
Binding Sites ◽  
Genome Organization ◽  
Mouse Liver ◽  
Ctcf Binding ◽  
Gene Promoters ◽  
3D Genome ◽  
Chromatin Interactions ◽  
The Impact

Abstract Several thousand sex-differential distal enhancers have been identified in mouse liver; however, their links to sex-biased genes and the impact of any sex-differences in nuclear organization and chromatin interactions are unknown. To address these issues, we first characterized 1,847 mouse liver genomic regions showing significant sex differential occupancy by cohesin and CTCF, two key 3D nuclear organizing factors. These sex-differential binding sites were primarily distal to sex-biased genes but rarely generated sex-differential TAD (topologically associating domain) or intra-TAD loop anchors, and were sometimes found in TADs without sex-biased genes. A substantial subset of sex-biased cohesin-non-CTCF binding sites, but not sex-biased cohesin-and-CTCF binding sites, overlapped sex-biased enhancers. Cohesin depletion reduced the expression of male-biased genes with distal, but not proximal, sex-biased enhancers by >10-fold, implicating cohesin in long-range enhancer interactions regulating sex-biased genes. Using circularized chromosome conformation capture-based sequencing (4C-seq), we showed that sex differences in distal sex-biased enhancer - promoter interactions are common. Intra-TAD loops with sex-independent cohesin-and-CTCF anchors conferred sex specificity to chromatin interactions indirectly, by insulating sex-biased enhancer - promoter contacts and by bringing sex-biased genes into closer proximity to sex-biased enhancers. Furthermore, sex-differential chromatin interactions involving sex-biased gene promoters, enhancers, and lncRNAs were associated with sex-biased binding of cohesin and/or CTCF. These studies elucidate how 3D genome organization impacts sex-biased gene expression in a non-reproductive tissue through both direct and indirect effects of cohesin and CTCF looping on distal enhancer interactions with sex-differentially expressed genes.

scholarly journals Impact of 3D genome organization, guided by cohesin and CTCF looping, on sex-biased chromatin interactions and gene expression in mouse liver

2020 ◽  
Author(s):  
Bryan J Matthews ◽  
David J Waxman
Keyword(s):  
Gene Expression ◽  
Sex Differences ◽  
Binding Sites ◽  
Genome Organization ◽  
Mouse Liver ◽  
Ctcf Binding ◽  
Gene Promoters ◽  
3D Genome ◽  
Chromatin Interactions ◽  
The Impact

Abstract Several thousand sex-differential distal enhancers have been identified in mouse liver; however, their links to sex-biased genes and the impact of any sex-differences in nuclear organization and chromatin interactions are unknown. To address these issues, we first characterized 1,847 mouse liver genomic regions showing significant sex differential occupancy by cohesin and CTCF, two key 3D nuclear organizing factors. These sex-differential binding sites were primarily distal to sex-biased genes but rarely generated sex-differential TAD (topologically associating domain) or intra-TAD loop anchors, and were sometimes found in TADs without sex-biased genes. A substantial subset of sex-biased cohesin-non-CTCF binding sites, but not sex-biased cohesin-and-CTCF binding sites, overlapped sex-biased enhancers. Cohesin depletion reduced the expression of male-biased genes with distal, but not proximal, sex-biased enhancers by >10-fold, implicating cohesin in long-range enhancer interactions regulating sex-biased genes. Using circularized chromosome conformation capture-based sequencing (4C-seq), we showed that sex differences in distal sex-biased enhancer - promoter interactions are common. Intra-TAD loops with sex-independent cohesin-and-CTCF anchors conferred sex specificity to chromatin interactions indirectly, by insulating sex-biased enhancer - promoter contacts and by bringing sex-biased genes into closer proximity to sex-biased enhancers. Furthermore, sex-differential chromatin interactions involving sex-biased gene promoters, enhancers, and lncRNAs were associated with sex-biased binding of cohesin and/or CTCF. These studies elucidate how 3D genome organization impacts sex-biased gene expression in a non-reproductive tissue through both direct and indirect effects of cohesin and CTCF looping on distal enhancer interactions with sex-differentially expressed genes.

scholarly journals HP1 drives de novo 3D genome reorganization in early Drosophila embryos

Nature ◽  
2021 ◽  
Author(s):  
Fides Zenk ◽  
Yinxiu Zhan ◽  
Pavel Kos ◽  
Eva Löser ◽  
Nazerke Atinbayeva ◽  
...  
Keyword(s):  
Genome Organization ◽  
Molecular Mechanisms ◽  
High Throughput Sequencing ◽  
De Novo ◽  
Early Embryo ◽  
Heterochromatin Protein ◽  
Chromosome Conformation ◽  
3D Genome ◽  
Genome Reorganization

AbstractFundamental features of 3D genome organization are established de novo in the early embryo, including clustering of pericentromeric regions, the folding of chromosome arms and the segregation of chromosomes into active (A-) and inactive (B-) compartments. However, the molecular mechanisms that drive de novo organization remain unknown1,2. Here, by combining chromosome conformation capture (Hi-C), chromatin immunoprecipitation with high-throughput sequencing (ChIP–seq), 3D DNA fluorescence in situ hybridization (3D DNA FISH) and polymer simulations, we show that heterochromatin protein 1a (HP1a) is essential for de novo 3D genome organization during Drosophila early development. The binding of HP1a at pericentromeric heterochromatin is required to establish clustering of pericentromeric regions. Moreover, HP1a binding within chromosome arms is responsible for overall chromosome folding and has an important role in the formation of B-compartment regions. However, depletion of HP1a does not affect the A-compartment, which suggests that a different molecular mechanism segregates active chromosome regions. Our work identifies HP1a as an epigenetic regulator that is involved in establishing the global structure of the genome in the early embryo.

scholarly journals Erythrocytes 3D genome organization in vertebrates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anastasia Ryzhkova ◽  
Alena Taskina ◽  
Anna Khabarova ◽  
Veniamin Fishman ◽  
Nariman Battulin
Keyword(s):  
Blood Cells ◽  
Genome Organization ◽  
Large Scale ◽  
Chromatin Condensation ◽  
Erythroid Differentiation ◽  
Interaction Patterns ◽  
3D Interaction ◽  
Interphase Chromosome ◽  
3D Genome ◽  
Contact Maps

AbstractGeneration of mature red blood cells, consisting mainly of hemoglobin, is a remarkable example of coordinated action of various signaling networks. Chromatin condensation is an essential step for terminal erythroid differentiation and subsequent nuclear expulsion in mammals. Here, we profiled 3D genome organization in the blood cells from ten species belonging to different vertebrate classes. Our analysis of contact maps revealed a striking absence of such 3D interaction patterns as loops or TADs in blood cells of all analyzed representatives. We also detect large-scale chromatin rearrangements in blood cells from mammals, birds, reptiles and amphibians: their contact maps display strong second diagonal pattern, representing an increased frequency of long-range contacts, unrelated to TADs or compartments. This pattern is completely atypical for interphase chromosome structure. We confirm that these principles of genome organization are conservative in vertebrate erythroid cells.

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