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Lee BH, Wu Z, Rhie SK. Characterizing chromatin interactions of regulatory elements and nucleosome positions, using Hi-C, Micro-C, and promoter capture Micro-C. Epigenetics Chromatin 2022; 15:41. [PMID: 36544209 PMCID: PMC9768916 DOI: 10.1186/s13072-022-00473-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/08/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Regulatory elements such as promoters, enhancers, and insulators interact each other to mediate molecular processes. To capture chromatin interactions of regulatory elements, 3C-derived methods such as Hi-C and Micro-C are developed. Here, we generated and analyzed Hi-C, Micro-C, and promoter capture Micro-C datasets with different sequencing depths to study chromatin interactions of regulatory elements and nucleosome positions in human prostate cancer cells. RESULTS Compared to Hi-C, Micro-C identifies more high-resolution loops, including ones around structural variants. By evaluating the effect of sequencing depth, we revealed that more than 2 billion reads of Micro-C are needed to detect chromatin interactions at 1 kb resolution. Moreover, we found that deep-sequencing identifies additional long-range loops that are longer than 1 Mb in distance. Furthermore, we found that more than 50% of the loops are involved in insulators while less than 10% of the loops are promoter-enhancer loops. To comprehensively capture chromatin interactions that promoters are involved in, we performed promoter capture Micro-C. Promoter capture Micro-C identifies loops near promoters with a lower amount of sequencing reads. Sequencing of 160 million reads of promoter capture Micro-C resulted in reaching a plateau of identifying loops. However, there was still a subset of promoters that are not involved in loops even after deep-sequencing. By integrating Micro-C with NOMe-seq and ChIP-seq, we found that active promoters involved in loops have a more accessible region with lower levels of DNA methylation and more highly phased nucleosomes, compared to active promoters that are not involved in loops. CONCLUSION We determined the required sequencing depth for Micro-C and promoter capture Micro-C to generate high-resolution chromatin interaction maps and loops. We also investigated the effect of sequencing coverage of Hi-C, Micro-C, and promoter capture Micro-C on detecting chromatin loops. Our analyses suggest the presence of distinct regulatory element groups, which are differently involved in nucleosome positions and chromatin interactions. This study does not only provide valuable insights on understanding chromatin interactions of regulatory elements, but also present guidelines for designing research projects on chromatin interactions among regulatory elements.
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Affiliation(s)
- Beoung Hun Lee
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Zexun Wu
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA
| | - Suhn K Rhie
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089, USA.
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2
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Li X, Lee L, Abnousi A, Yu M, Liu W, Huang L, Li Y, Hu M. SnapHiC2: A computationally efficient loop caller for single cell Hi-C data. Comput Struct Biotechnol J 2022; 20:2778-2783. [PMID: 35685374 PMCID: PMC9168059 DOI: 10.1016/j.csbj.2022.05.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 01/11/2023] Open
Abstract
Single cell Hi-C (scHi-C) technologies enable the study of chromatin spatial organization directly from complex tissues at single cell resolution. However, the identification of chromatin loops from single cells is challenging, largely due to the extremely sparse data. Our recently developed SnapHiC pipeline provides the first tool to map chromatin loops from scHi-C data, but it is computationally intensive. Here we introduce SnapHiC2, which adapts a sliding window approximation when imputing missing contacts in each single cell and reduces both memory usage and computational time by 70%. SnapHiC2 can identify 5 Kb resolution chromatin loops with high sensitivity and accuracy and help to suggest target genes for GWAS variants in a cell-type-specific manner. SnapHiC2 is freely available at: https://github.com/HuMingLab/SnapHiC/releases/tag/v0.2.2.
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Affiliation(s)
- Xiaoqi Li
- Carolina Health Informatics Program, University of North Carolina, Chapel Hill, NC, USA
| | - Lindsay Lee
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Armen Abnousi
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Miao Yu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Weifang Liu
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA
| | - Le Huang
- Curriculum in Bioinformatics and Computational Biology, University of North Carolina, Chapel Hill, NC, USA
| | - Yun Li
- Department of Biostatistics, University of North Carolina, Chapel Hill, NC, USA
- Department of Genetics, University of North Carolina, Chapel Hill, NC, USA
- Department of Computer Science, University of North Carolina, Chapel Hill, NC, USA
| | - Ming Hu
- Department of Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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López-Fuentes E, Hernández-Hernández G, De Las Peñas A, Castaño I. Subtelomeric Chromatin Structure by Chromosome Conformation Capture (3C)-qPCR Methodology in Candida glabrata. Methods Mol Biol 2022; 2542:71-89. [PMID: 36008657 DOI: 10.1007/978-1-0716-2549-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Chromatin architecture has an enormous impact on gene regulation, DNA replication, repair, and packaging. Chromatin is organized in a complex hierarchical manner in which distant fragments of DNA can interact with each other through DNA loops. DNA loops can interact between themselves to form topologically associated domains (TADs) that are further organized into functional compartments. In the last two decades, Chromatin Conformation Capture (3C technology) and its high-throughput derivatives allowed detailed analysis of the chromatin architecture. The 3C method is based on ligation of distant fragments brought together by DNA looping. The method analyzes a particular genomic region of interest and quantifies the interactions between a defined fragment with all the surrounding fragments of the region. It consists of four steps: (1) The long-distance interacting chromatin fragments are fixed with formaldehyde in whole cells which are then lysed; (2) the fixed chromatin is digested with a carefully chosen restriction enzymes to separate intervening DNA fragments; (3) the fragments brought into proximity by DNA looping are ligated in conditions favoring intramolecular ligation; and (4) the interactions are quantified by quantitative PCR using the TaqMan technology and unidirectional primers. Herein, we describe the use of this methodology to analyze the chromatin conformation at a subtelomeric locus containing three genes encoding adhesins and several cis-regulatory elements, in the pathogenic yeast Candida glabrata.
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Affiliation(s)
- Eunice López-Fuentes
- Division of Hematology and Oncology, Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA
| | - Grecia Hernández-Hernández
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, A.C. División de Biología Molecular, San Luis Potosí, Mexico
| | - Alejandro De Las Peñas
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, A.C. División de Biología Molecular, San Luis Potosí, Mexico
| | - Irene Castaño
- IPICYT, Instituto Potosino de Investigación Científica y Tecnológica, A.C. División de Biología Molecular, San Luis Potosí, Mexico.
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Chiliński M, Sengupta K, Plewczynski D. From DNA human sequence to the chromatin higher order organisation and its biological meaning: Using biomolecular interaction networks to understand the influence of structural variation on spatial genome organisation and its functional effect. Semin Cell Dev Biol 2021; 121:171-185. [PMID: 34429265 DOI: 10.1016/j.semcdb.2021.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 08/06/2021] [Accepted: 08/12/2021] [Indexed: 12/30/2022]
Abstract
The three-dimensional structure of the human genome has been proven to have a significant functional impact on gene expression. The high-order spatial chromatin is organised first by looping mediated by multiple protein factors, and then it is further formed into larger structures of topologically associated domains (TADs) or chromatin contact domains (CCDs), followed by A/B compartments and finally the chromosomal territories (CTs). The genetic variation observed in human population influences the multi-scale structures, posing a question regarding the functional impact of structural variants reflected by the variability of the genes expression patterns. The current methods of evaluating the functional effect include eQTLs analysis which uses statistical testing of influence of variants on spatially close genes. Rarely, non-coding DNA sequence changes are evaluated by their impact on the biomolecular interaction network (BIN) reflecting the cellular interactome that can be analysed by the classical graph-theoretic algorithms. Therefore, in the second part of the review, we introduce the concept of BIN, i.e. a meta-network model of the complete molecular interactome developed by integrating various biological networks. The BIN meta-network model includes DNA-protein binding by the plethora of protein factors as well as chromatin interactions, therefore allowing connection of genomics with the downstream biomolecular processes present in a cell. As an illustration, we scrutinise the chromatin interactions mediated by the CTCF protein detected in a ChIA-PET experiment in the human lymphoblastoid cell line GM12878. In the corresponding BIN meta-network the DNA spatial proximity is represented as a graph model, combined with the Proteins-Interaction Network (PIN) of human proteome using the Gene Association Network (GAN). Furthermore, we enriched the BIN with the signalling and metabolic pathways and Gene Ontology (GO) terms to assert its functional context. Finally, we mapped the Single Nucleotide Polymorphisms (SNPs) from the GWAS studies and identified the chromatin mutational hot-spots associated with a significant enrichment of SNPs related to autoimmune diseases. Afterwards, we mapped Structural Variants (SVs) from healthy individuals of 1000 Genomes Project and identified an interesting example of the missing protein complex associated with protein Q6GYQ0 due to a deletion on chromosome 14. Such an analysis using the meta-network BIN model is therefore helpful in evaluating the influence of genetic variation on spatial organisation of the genome and its functional effect in a cell.
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Affiliation(s)
- Mateusz Chiliński
- Laboratory of Bioinformatics and Computational Genomics, Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland; Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Kaustav Sengupta
- Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | - Dariusz Plewczynski
- Laboratory of Bioinformatics and Computational Genomics, Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland; Laboratory of Functional and Structural Genomics, Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland.
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5
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Karasu N, Sexton T. Assessment of 3D Interactions Between Promoters and Distal Regulatory Elements with Promoter Capture Hi-C (PCHi-C). Methods Mol Biol 2021; 2351:229-48. [PMID: 34382193 DOI: 10.1007/978-1-0716-1597-3_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Chromosome conformation capture and its variants interrogate population-average chromatin structure at a higher resolution and throughput than microscopic methods. Capture Hi-C is a variant tailored for the simultaneous assessment of all interactions with thousands of specific bait sequences, so is particularly suited to genome-wide studies of promoter interactions with distal regulatory elements, such as enhancers. We present the principles and methods for Promoter Capture Hi-C (PCHi-C), from experimental design to data analysis.
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6
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Abstract
Chromosome conformation capture and its variants have allowed chromatin topology to be interrogated at a superior resolution and throughput than by microscopic methods. Among the method derivatives, 4C-seq (circular chromosome conformation capture, coupled to high-throughput sequencing) is a versatile, cost-effective means of assessing all chromatin interactions with a specific genomic region of interest, making it particularly suitable for interrogating chromatin looping events. We present the principles and procedures for designing and implementing successful 4C-seq experiments.
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7
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Kruse K, Hug CB, Vaquerizas JM. FAN-C: a feature-rich framework for the analysis and visualisation of chromosome conformation capture data. Genome Biol 2020; 21:303. [PMID: 33334380 PMCID: PMC7745377 DOI: 10.1186/s13059-020-02215-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 11/30/2020] [Indexed: 01/01/2023] Open
Abstract
Chromosome conformation capture data, particularly from high-throughput approaches such as Hi-C, are typically very complex to analyse. Existing analysis tools are often single-purpose, or limited in compatibility to a small number of data formats, frequently making Hi-C analyses tedious and time-consuming. Here, we present FAN-C, an easy-to-use command-line tool and powerful Python API with a broad feature set covering matrix generation, analysis, and visualisation for C-like data ( https://github.com/vaquerizaslab/fanc ). Due to its compatibility with the most prevalent Hi-C storage formats, FAN-C can be used in combination with a large number of existing analysis tools, thus greatly simplifying Hi-C matrix analysis.
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Affiliation(s)
- Kai Kruse
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany
| | - Clemens B Hug
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany
| | - Juan M Vaquerizas
- Max Planck Institute for Molecular Biomedicine, Roentgenstrasse 20, 48149, Muenster, Germany.
- MRC London Institute of Medical Sciences, Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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Abstract
The organization of chromatin into higher order structures is essential for chromosome segregation, the repair of DNA-damage, and the regulation of gene expression. Using Micro-C XL to detect chromosomal interactions, we observed the pervasive presence of cohesin-dependent loops with defined positions throughout the genome of budding yeast, as seen in mammalian cells. In early S phase, cohesin stably binds to cohesin associated regions (CARs) genome-wide. Subsequently, positioned loops accumulate with CARs at the bases of the loops. Cohesin regulators Wpl1 and Pds5 alter the levels and distribution of cohesin at CARs, changing the pattern of positioned loops. From these observations, we propose that cohesin with loop extrusion activity is stopped by preexisting CAR-bound cohesins, generating positioned loops. The patterns of loops observed in a population of wild-type and mutant cells can be explained by this mechanism, coupled with a heterogeneous residency of cohesin at CARs in individual cells.
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Affiliation(s)
- Lorenzo Costantino
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Tsung-Han S Hsieh
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Rebecca Lamothe
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Douglas Koshland
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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9
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Abstract
The organization of chromatin into higher order structures is essential for chromosome segregation, the repair of DNA-damage, and the regulation of gene expression. Using Micro-C XL to detect chromosomal interactions, we observed the pervasive presence of cohesin-dependent loops with defined positions throughout the genome of budding yeast, as seen in mammalian cells. In early S phase, cohesin stably binds to cohesin associated regions (CARs) genome-wide. Subsequently, positioned loops accumulate with CARs at the bases of the loops. Cohesin regulators Wpl1 and Pds5 alter the levels and distribution of cohesin at CARs, changing the pattern of positioned loops. From these observations, we propose that cohesin with loop extrusion activity is stopped by preexisting CAR-bound cohesins, generating positioned loops. The patterns of loops observed in a population of wild-type and mutant cells can be explained by this mechanism, coupled with a heterogeneous residency of cohesin at CARs in individual cells.
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Affiliation(s)
- Lorenzo Costantino
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Tsung-Han S Hsieh
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Rebecca Lamothe
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Douglas Koshland
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
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10
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Roayaei Ardakany A, Gezer HT, Lonardi S, Ay F. Mustache: multi-scale detection of chromatin loops from Hi-C and Micro-C maps using scale-space representation. Genome Biol 2020; 21:256. [PMID: 32998764 PMCID: PMC7528378 DOI: 10.1186/s13059-020-02167-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 09/16/2020] [Indexed: 12/20/2022] Open
Abstract
We present MUSTACHE, a new method for multi-scale detection of chromatin loops from Hi-C and Micro-C contact maps. MUSTACHE employs scale-space theory, a technical advance in computer vision, to detect blob-shaped objects in contact maps. MUSTACHE is scalable to kilobase-resolution maps and reports loops that are highly consistent between replicates and between Hi-C and Micro-C datasets. Compared to other loop callers, such as HiCCUPS and SIP, MUSTACHE recovers a higher number of published ChIA-PET and HiChIP loops as well as loops linking promoters to regulatory elements. Overall, MUSTACHE enables an efficient and comprehensive analysis of chromatin loops. Available at: https://github.com/ay-lab/mustache .
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Affiliation(s)
- Abbas Roayaei Ardakany
- Centers for Autoimmunity and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, 92037 CA USA
- Computer Science and Engineering, University of California, Riverside, Riverside, 92521 CA USA
| | - Halil Tuvan Gezer
- Centers for Autoimmunity and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, 92037 CA USA
- Computer Science and Engineering, Sabanci University, Tuzla, Istanbul, 34956 Turkey
| | - Stefano Lonardi
- Computer Science and Engineering, University of California, Riverside, Riverside, 92521 CA USA
| | - Ferhat Ay
- Centers for Autoimmunity and Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, 92037 CA USA
- School of Medicine, University of California, San Diego, San Diego, 92093 CA USA
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11
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Ibn-Salem J, Andrade-Navarro MA. 7C: Computational Chromosome Conformation Capture by Correlation of ChIP-seq at CTCF motifs. BMC Genomics 2019; 20:777. [PMID: 31653198 PMCID: PMC6814980 DOI: 10.1186/s12864-019-6088-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/09/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Knowledge of the three-dimensional structure of the genome is necessary to understand how gene expression is regulated. Recent experimental techniques such as Hi-C or ChIA-PET measure long-range chromatin interactions genome-wide but are experimentally elaborate, have limited resolution and such data is only available for a limited number of cell types and tissues. RESULTS While ChIP-seq was not designed to detect chromatin interactions, the formaldehyde treatment in the ChIP-seq protocol cross-links proteins with each other and with DNA. Consequently, also regions that are not directly bound by the targeted TF but interact with the binding site via chromatin looping are co-immunoprecipitated and sequenced. This produces minor ChIP-seq signals at loop anchor regions close to the directly bound site. We use the position and shape of ChIP-seq signals around CTCF motif pairs to predict whether they interact or not. We implemented this approach in a prediction method, termed Computational Chromosome Conformation Capture by Correlation of ChIP-seq at CTCF motifs (7C). We applied 7C to all CTCF motif pairs within 1 Mb in the human genome and validated predicted interactions with high-resolution Hi-C and ChIA-PET. A single ChIP-seq experiment from known architectural proteins (CTCF, Rad21, Znf143) but also from other TFs (like TRIM22 or RUNX3) predicts loops accurately. Importantly, 7C predicts loops in cell types and for TF ChIP-seq datasets not used in training. CONCLUSION 7C predicts chromatin loops which can help to associate TF binding sites to regulated genes. Furthermore, profiling of hundreds of ChIP-seq datasets results in novel candidate factors functionally involved in chromatin looping. Our method is available as an R/Bioconductor package: http://bioconductor.org/packages/sevenC .
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Affiliation(s)
- Jonas Ibn-Salem
- Faculty of Biology, Johannes Gutenberg University of Mainz, 55128, Mainz, Germany.
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Huang J, Jiang Y, Zheng H, Ji X. BAT Hi-C maps global chromatin interactions in an efficient and economical way. Methods 2019; 170:38-47. [PMID: 31442560 DOI: 10.1016/j.ymeth.2019.08.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 08/15/2019] [Indexed: 11/18/2022] Open
Abstract
Chromosome Conformation Capture (3C)-based technologies, such as Hi-C, have represented a significant breakthrough in investigating the structure and function of higher-order genome architecture. However, the mapping of global chromatin interactions remains challenging across many biological conditions due to high background noise and financial constraints, especially for small laboratories. Here, we describe the Bridge linker-Alul-Tn5 Hi-C (BAT Hi-C) method, which is a simple and efficient method for delineating chromatin conformational features of mouse embryonic stem (mES) cells and uncover DNA loops. This protocol combines Alul fragmentation and biotinylated linker-mediated proximity ligation to obtain kilobase (kb) resolution with a marked increase in the amount of unique read pairs. The protocol also includes chromatin isolation to reduce background noise and Tn5 tagmentation to cut down on preparation time. Importantly, with only one-third sequencing depth, our method revealed the same spectrum of chromatin contacts as in situ Hi-C. BAT Hi-C is an economical (i.e., approximately $40 for library preparation) and straightforward (total hands-on time of 3 days) tool that is ideal for the in-depth analysis of long-range chromatin looping events in a genome-wide fashion.
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Affiliation(s)
- Jie Huang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
| | - Yongpeng Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Haonan Zheng
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China.
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Sadowski M, Kraft A, Szalaj P, Wlasnowolski M, Tang Z, Ruan Y, Plewczynski D. Spatial chromatin architecture alteration by structural variations in human genomes at the population scale. Genome Biol 2019; 20:148. [PMID: 31362752 PMCID: PMC6664780 DOI: 10.1186/s13059-019-1728-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 05/30/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The number of reported examples of chromatin architecture alterations involved in the regulation of gene transcription and in disease is increasing. However, no genome-wide testing has been performed to assess the abundance of these events and their importance relative to other factors affecting genome regulation. This is particularly interesting given that a vast majority of genetic variations identified in association studies are located outside coding sequences. This study attempts to address this lack by analyzing the impact on chromatin spatial organization of genetic variants identified in individuals from 26 human populations and in genome-wide association studies. RESULTS We assess the tendency of structural variants to accumulate in spatially interacting genomic segments and design an algorithm to model chromatin conformational changes caused by structural variations. We show that differential gene transcription is closely linked to the variation in chromatin interaction networks mediated by RNA polymerase II. We also demonstrate that CTCF-mediated interactions are well conserved across populations, but enriched with disease-associated SNPs. Moreover, we find boundaries of topological domains as relatively frequent targets of duplications, which suggest that these duplications can be an important evolutionary mechanism of genome spatial organization. CONCLUSIONS This study assesses the critical impact of genetic variants on the higher-order organization of chromatin folding and provides insight into the mechanisms regulating gene transcription at the population scale, of which local arrangement of chromatin loops seems to be the most significant. It provides the first insight into the variability of the human 3D genome at the population scale.
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Affiliation(s)
- Michal Sadowski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Faculty of Physics, University of Warsaw, Pasteura 5, 02-093 Warsaw, Poland
| | - Agnieszka Kraft
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland
| | - Przemyslaw Szalaj
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Centre for Innovative Research, Medical University of Bialystok, Kilinskiego 1, 15-089 Bialystok, Poland
- I-BioStat, Hasselt University, Agoralaan building D, BE3590 Diepenbeek, Belgium
| | - Michal Wlasnowolski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland
| | - Zhonghui Tang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080 China
| | - Yijun Ruan
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Drive, Farmington, CT 06032 USA
| | - Dariusz Plewczynski
- Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
- Faculty of Mathematics and Information Science, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland
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14
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Ben Zouari Y, Molitor AM, Sikorska N, Pancaldi V, Sexton T. ChiCMaxima: a robust and simple pipeline for detection and visualization of chromatin looping in Capture Hi-C. Genome Biol 2019; 20:102. [PMID: 31118054 PMCID: PMC6532271 DOI: 10.1186/s13059-019-1706-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 05/03/2019] [Indexed: 12/19/2022] Open
Abstract
Capture Hi-C (CHi-C) is a new technique for assessing genome organization based on chromosome conformation capture coupled to oligonucleotide capture of regions of interest, such as gene promoters. Chromatin loop detection is challenging because existing Hi-C/4C-like tools, which make different assumptions about the technical biases presented, are often unsuitable. We describe a new approach, ChiCMaxima, which uses local maxima combined with limited filtering to detect DNA looping interactions, integrating information from biological replicates. ChiCMaxima shows more stringency and robustness compared to previously developed tools. The tool includes a GUI browser for flexible visualization of CHi-C profiles alongside epigenomic tracks.
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Affiliation(s)
- Yousra Ben Zouari
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- CNRS UMR7104, Illkirch, France
- INSERM U1258, Illkirch, France
- University of Strasbourg, Illkirch, France
| | - Anne M Molitor
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- CNRS UMR7104, Illkirch, France
- INSERM U1258, Illkirch, France
- University of Strasbourg, Illkirch, France
| | - Natalia Sikorska
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
- CNRS UMR7104, Illkirch, France
- INSERM U1258, Illkirch, France
- University of Strasbourg, Illkirch, France
| | - Vera Pancaldi
- Centre de Recherches en Cancérologie de Toulouse (CRCT), INSERM U1037, Toulouse, France
- University Paul Sabatier III, Toulouse, France
- Barcelona Supercomputing Center, Barcelona, Spain
| | - Tom Sexton
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France.
- CNRS UMR7104, Illkirch, France.
- INSERM U1258, Illkirch, France.
- University of Strasbourg, Illkirch, France.
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15
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Abstract
Background Super-enhancers or stretch enhancers are clusters of active enhancers that often coordinate cell-type specific gene regulation during development and differentiation. In addition, the enrichment of disease-associated single nucleotide polymorphism in super-enhancers indicates their critical function in disease-specific gene regulation. However, little is known about the function of super-enhancers beyond gene regulation. Results In this study, through a comprehensive analysis of super-enhancers in 30 human cell/tissue types, we identified a new class of super-enhancers which are constitutively active across most cell/tissue types. These ‘common’ super-enhancers are associated with universally highly expressed genes in contrast to the canonical definition of super-enhancers that assert cell-type specific gene regulation. In addition, the genome sequence of these super-enhancers is highly conserved by evolution and among humans, advocating their universal function in genome regulation. Integrative analysis of 3D chromatin loops demonstrates that, in comparison to the cell-type specific super-enhancers, the cell-type common super-enhancers present a striking association with rapidly recovering loops. Conclusions In this study, we propose that a new class of super-enhancers may play an important role in the early establishment of 3D chromatin structure. Electronic supplementary material The online version of this article (10.1186/s12859-019-2646-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jayoung Ryu
- Department of Biological Sciences, KAIST, Daejeon, 34141, South Korea
| | - Hyunwoong Kim
- Department of Biological Sciences, KAIST, Daejeon, 34141, South Korea
| | - Dongchan Yang
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, South Korea
| | - Andrew J Lee
- Department of Biological Sciences, KAIST, Daejeon, 34141, South Korea
| | - Inkyung Jung
- Department of Biological Sciences, KAIST, Daejeon, 34141, South Korea.
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16
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Abstract
Genome is a complex hierarchical structure, and its spatial organization plays an important role in its function. Chromatin loops and topological domains form the basic structural units of this multiscale organization and are essential to orchestrate complex regulatory networks and transcription mechanisms. They also form higher-order structures such as chromosomal compartments and chromosome territories. Each level of this intrinsic architecture is governed by principles and mechanisms that we only start to understand. In this review, we summarize the current view of the genome architecture on the scales ranging from chromatin loops to the whole genome. We describe cell-to-cell variability, links between genome reorganization and various genomic processes, such as chromosome X inactivation and cell differentiation, and the interplay between different experimental techniques.
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Affiliation(s)
- Przemyslaw Szalaj
- Centre for Innovative Research, Medical University of Bialystok, Białystok, Poland.
- I-BioStat, Hasselt University, Hasselt, Belgium.
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
| | - Dariusz Plewczynski
- Centre for Innovative Research, Medical University of Bialystok, Białystok, Poland
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Mathematics and Information Science, Warsaw University of Technology, Warsaw, Poland
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17
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Kaiser VB, Semple CA. Chromatin loop anchors are associated with genome instability in cancer and recombination hotspots in the germline. Genome Biol 2018; 19:101. [PMID: 30060743 PMCID: PMC6066925 DOI: 10.1186/s13059-018-1483-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 07/13/2018] [Indexed: 01/07/2023] Open
Abstract
Background Chromatin loops form a basic unit of interphase nuclear organization, with chromatin loop anchor points providing contacts between regulatory regions and promoters. However, the mutational landscape at these anchor points remains under-studied. Here, we describe the unusual patterns of somatic mutations and germline variation associated with loop anchor points and explore the underlying features influencing these patterns. Results Analyses of whole genome sequencing datasets reveal that anchor points are strongly depleted for single nucleotide variants (SNVs) in tumours. Despite low SNV rates in their genomic neighbourhood, anchor points emerge as sites of evolutionary innovation, showing enrichment for structural variant (SV) breakpoints and a peak of SNVs at focal CTCF sites within the anchor points. Both CTCF-bound and non-CTCF anchor points harbour an excess of SV breakpoints in multiple tumour types and are prone to double-strand breaks in cell lines. Common fragile sites, which are hotspots for genome instability, also show elevated numbers of intersecting loop anchor points. Recurrently disrupted anchor points are enriched for genes with functions in cell cycle transitions and regions associated with predisposition to cancer. We also discover a novel class of CTCF-bound anchor points which overlap meiotic recombination hotspots and are enriched for the core PRDM9 binding motif, suggesting that the anchor points have been foci for diversity generated during recent human evolution. Conclusions We suggest that the unusual chromatin environment at loop anchor points underlies the elevated rates of variation observed, marking them as sites of regulatory importance but also genomic fragility. Electronic supplementary material The online version of this article (10.1186/s13059-018-1483-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Vera B Kaiser
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK.
| | - Colin A Semple
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, EH4 2XU, UK
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18
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Glinsky GV. Contribution of transposable elements and distal enhancers to evolution of human-specific features of interphase chromatin architecture in embryonic stem cells. Chromosome Res 2018; 26:61-84. [PMID: 29335803 DOI: 10.1007/s10577-018-9571-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/20/2017] [Accepted: 01/02/2018] [Indexed: 11/28/2022]
Abstract
Transposable elements have made major evolutionary impacts on creation of primate-specific and human-specific genomic regulatory loci and species-specific genomic regulatory networks (GRNs). Molecular and genetic definitions of human-specific changes to GRNs contributing to development of unique to human phenotypes remain a highly significant challenge. Genome-wide proximity placement analysis of diverse families of human-specific genomic regulatory loci (HSGRL) identified topologically associating domains (TADs) that are significantly enriched for HSGRL and designated rapidly evolving in human TADs. Here, the analysis of HSGRL, hESC-enriched enhancers, super-enhancers (SEs), and specific sub-TAD structures termed super-enhancer domains (SEDs) has been performed. In the hESC genome, 331 of 504 (66%) of SED-harboring TADs contain HSGRL and 68% of SEDs co-localize with HSGRL, suggesting that emergence of HSGRL may have rewired SED-associated GRNs within specific TADs by inserting novel and/or erasing existing non-coding regulatory sequences. Consequently, markedly distinct features of the principal regulatory structures of interphase chromatin evolved in the hESC genome compared to mouse: the SED quantity is 3-fold higher and the median SED size is significantly larger. Concomitantly, the overall TAD quantity is increased by 42% while the median TAD size is significantly decreased (p = 9.11E-37) in the hESC genome. Present analyses illustrate a putative global role for transposable elements and HSGRL in shaping the human-specific features of the interphase chromatin organization and functions, which are facilitated by accelerated creation of novel transcription factor binding sites and new enhancers driven by targeted placement of HSGRL at defined genomic coordinates. A trend toward the convergence of TAD and SED architectures of interphase chromatin in the hESC genome may reflect changes of 3D-folding patterns of linear chromatin fibers designed to enhance both regulatory complexity and functional precision of GRNs by creating predominantly a single gene (or a set of functionally linked genes) per regulatory domain structures. Collectively, present analyses reveal critical evolutionary contributions of transposable elements and distal enhancers to creation of thousands primate- and human-specific elements of a chromatin folding code, which defines the 3D context of interphase chromatin both restricting and facilitating biological functions of GRNs.
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Affiliation(s)
- Gennadi V Glinsky
- Institute of Engineering in Medicine, University of California, San Diego, 9500 Gilman Dr. MC 0435, La Jolla, CA, 92093-0435, USA.
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19
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Abstract
The study of nuclear architecture promises novel insights into genome function and regulation. Hereby, quantitative methods based on chromosome conformation capture (3C) revolutionized the field, as they allow accurate and unbiased characterization of 3D genome organization of genomic regions of interest. The choice of the appropriate 3C derivate is crucial to acquire results suited for a specific research question. Circular 3C (4C) is the method of choice to study the genome-wide 3D architecture of a specific genomic region of interest. Here, I present a robust 4C protocol, established in Arabidopsis thaliana, which can be employed by any experienced molecular biologist and is applicable in various other plant species.
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20
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Abstract
Nuclear organization and higher-order chromosome structure in interphase nuclei are thought to have important effects on fundamental biological processes, including chromosome condensation, replication, and transcription. Until recently, however, nuclear organization could only be analyzed microscopically. The development of chromatin conformation capture (3C)-based techniques now allows a detailed look at chromosomal architecture from the level of individual loci to the entire genome. Here we provide a robust Hi-C protocol, allowing the analysis of nuclear organization in nuclei from different wild-type and mutant plant tissues. This method is quantitative and provides a highly efficient and comprehensive way to study chromatin organization during plant development, in response to different environmental stimuli, and in mutants disrupting a variety of processes, including epigenetic pathways regulating gene expression.
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21
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Abstract
Major histocompatibility complex (MHC) class II molecules are essential for processing and presenting exogenous pathogen antigens to activate CD4+ T cells. Given their central role in adaptive immune responses, MHC class II genes are tightly regulated in a tissue- and activation-specific manner. The regulation of MHC class II gene expression involves various transcription factors that interact with conserved proximal cis-acting regulatory promoter elements, as well as MHC class II transactivator that interacts with a variety of chromatin remodeling machineries. Recent studies also identified distal regulatory elements within MHC class II gene locus that provide enormous insight into the long-range coordination of MHC class II gene expression. Novel therapeutic modalities that can modify MHC class II genes at the epigenetic level are emerging and are currently in preclinical and clinical trials. This review will focus on the role of chromatin remodeling, particularly remodeling that involves histone acetylation, in the constitutive and inducible regulation of MHC class II gene expression.
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Affiliation(s)
- K Suzuki
- Faculty of Medical Technology, Teikyo University, Itabashi, Japan.
| | - Y Luo
- Faculty of Medical Technology, Teikyo University, Itabashi, Japan
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22
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Knoch TA, Wachsmuth M, Kepper N, Lesnussa M, Abuseiris A, Ali Imam AM, Kolovos P, Zuin J, Kockx CEM, Brouwer RWW, van de Werken HJG, van IJcken WFJ, Wendt KS, Grosveld FG. The detailed 3D multi-loop aggregate/rosette chromatin architecture and functional dynamic organization of the human and mouse genomes. Epigenetics Chromatin 2016; 9:58. [PMID: 28035242 PMCID: PMC5192698 DOI: 10.1186/s13072-016-0089-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 09/01/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The dynamic three-dimensional chromatin architecture of genomes and its co-evolutionary connection to its function-the storage, expression, and replication of genetic information-is still one of the central issues in biology. Here, we describe the much debated 3D architecture of the human and mouse genomes from the nucleosomal to the megabase pair level by a novel approach combining selective high-throughput high-resolution chromosomal interaction capture (T2C), polymer simulations, and scaling analysis of the 3D architecture and the DNA sequence. RESULTS The genome is compacted into a chromatin quasi-fibre with ~5 ± 1 nucleosomes/11 nm, folded into stable ~30-100 kbp loops forming stable loop aggregates/rosettes connected by similar sized linkers. Minor but significant variations in the architecture are seen between cell types and functional states. The architecture and the DNA sequence show very similar fine-structured multi-scaling behaviour confirming their co-evolution and the above. CONCLUSIONS This architecture, its dynamics, and accessibility, balance stability and flexibility ensuring genome integrity and variation enabling gene expression/regulation by self-organization of (in)active units already in proximity. Our results agree with the heuristics of the field and allow "architectural sequencing" at a genome mechanics level to understand the inseparable systems genomic properties.
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Affiliation(s)
- Tobias A. Knoch
- Biophysical Genomics, Department of Cell Biology and Genetics, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Malte Wachsmuth
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Meyerhofstr. 1, 69117 Heidelberg, Germany
| | - Nick Kepper
- Biophysical Genomics, Department of Cell Biology and Genetics, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
- Genome Organization and Function, BioQuant and German Cancer Research Center, Im Neuenheimer Feld 267, 69120 Heidelberg, Germany
| | - Michael Lesnussa
- Biophysical Genomics, Department of Cell Biology and Genetics, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - Anis Abuseiris
- Biophysical Genomics, Department of Cell Biology and Genetics, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
| | - A. M. Ali Imam
- Biophysical Genomics, Department of Cell Biology and Genetics, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
- Cell Biology, Department Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Petros Kolovos
- Biophysical Genomics, Department of Cell Biology and Genetics, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, The Netherlands
- Cell Biology, Department Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Jessica Zuin
- Cohesin in Chromatin Structure and Gene Regulation, Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Christel E. M. Kockx
- Center for Biomics, Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Rutger W. W. Brouwer
- Center for Biomics, Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Harmen J. G. van de Werken
- Cell Biology, Department Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Wilfred F. J. van IJcken
- Center for Biomics, Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Kerstin S. Wendt
- Cohesin in Chromatin Structure and Gene Regulation, Department of Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
| | - Frank G. Grosveld
- Cell Biology, Department Cell Biology and Genetics, Erasmus MC, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
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23
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Abstract
3D chromatin organization is essential for many aspects of transcriptional regulation. Circular Chromosome Conformation Capture followed by Illumina sequencing (4C-seq) is among the most powerful techniques to determine 3D chromatin organization. 4C-seq, like other modifications of the original 3C technique, uses the principle of "proximity ligation" to identify and quantify ten thousands of genomic interactions at a kilobase scale in a single experiment for predefined loci in the genome.In this chapter we focus on the experimental steps in the 4C-seq protocol, providing detailed descriptions on the preparation of cells, the construction of the circularized 3C library and the generation of the Illumina high throughput sequencing library. This protocol is particularly suited for the use of mammalian tissue samples, but can be used with minimal changes on circulating cells and cell lines from other sources as well. In the final section of this chapter, we provide a brief overview of data analysis approaches, accompanied by links to publicly available analysis tools.
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Affiliation(s)
- Mélody Matelot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, University Paris-Saclay, 1 Avenue de la terrasse, 91198, Gif sur Yvette, France
| | - Daan Noordermeer
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris Sud, University Paris-Saclay, 1 Avenue de la terrasse, 91198, Gif sur Yvette, France.
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24
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Mora A, Sandve GK, Gabrielsen OS, Eskeland R. In the loop: promoter-enhancer interactions and bioinformatics. Brief Bioinform 2015; 17:980-995. [PMID: 26586731 PMCID: PMC5142009 DOI: 10.1093/bib/bbv097] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/26/2015] [Indexed: 12/17/2022] Open
Abstract
Enhancer-promoter regulation is a fundamental mechanism underlying differential transcriptional regulation. Spatial chromatin organization brings remote enhancers in contact with target promoters in cis to regulate gene expression. There is considerable evidence for promoter-enhancer interactions (PEIs). In the recent years, genome-wide analyses have identified signatures and mapped novel enhancers; however, being able to precisely identify their target gene(s) requires massive biological and bioinformatics efforts. In this review, we give a short overview of the chromatin landscape and transcriptional regulation. We discuss some key concepts and problems related to chromatin interaction detection technologies, and emerging knowledge from genome-wide chromatin interaction data sets. Then, we critically review different types of bioinformatics analysis methods and tools related to representation and visualization of PEI data, raw data processing and PEI prediction. Lastly, we provide specific examples of how PEIs have been used to elucidate a functional role of non-coding single-nucleotide polymorphisms. The topic is at the forefront of epigenetic research, and by highlighting some future bioinformatics challenges in the field, this review provides a comprehensive background for future PEI studies.
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25
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Abstract
Cohesin is a ring-shaped complex, conserved from yeast to human, that was named for its ability to mediate sister chromatid cohesion. This function is essential for chromosome segregation in both mitosis and meiosis, and also for DNA repair. In addition, more recent studies have shown that cohesin influences gene expression during development through mechanisms that likely involve DNA looping and interactions with several transcriptional regulators. Here, we provide an overview of how cohesin functions, highlighting its role both in development and in disease.
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Affiliation(s)
- Silvia Remeseiro
- Chromosome Dynamics Group, Molecular Oncology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
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