Project description:Characterizing the relationship between genome form and function requires methods both for zooming out, to globally survey the genomic architectural landscape, and for zooming in, to investigate regions of interest at high resolution. High throughput methods based on chromosome conformation capture (3C) have greatly advanced our understanding of the three-dimensional (3D) organization of genomes, but are limited in resolution by their reliance on restriction enzymes. Here we describe a method for comprehensively mapping global chromatin contacts that uses DNaseI for chromatin fragmentation, leading to greatly improved efficiency and resolution. Coupling this method with DNA capture technology provides a high-throughput approach for targeted mapping of fine-scale chromatin architecture. We applied targeted DNase Hi-C to characterize the 3D organization of 1,030 lincRNA promoters in two human cell lines, and identified thousands of high-confidence lincRNA promoter-associated chromatin contacts at 1 kilobase pair (kbp) resolution. Detailed analysis of these contacts reveals that expression of lincRNAs is tightly controlled by complex mechanisms involving both super-enhancers and the polycomb repressive complex. Our results provide the first glimpse of the cell-type-specific 3D organization of lincRNA genes. DNase Hi-C assay (x1 replicate) in H1 and K562 cells, respectively. Targeted DNase Hi-C assays of the 220kb promoter-enhancer library (x1 replicate) and the 5Mb lincRNA promoter library (x2 replicate), in H1 and K562 cells, respectively.
Project description:Characterizing the relationship between genome form and function requires methods both for zooming out, to globally survey the genomic architectural landscape, and for zooming in, to investigate regions of interest at high resolution. High throughput methods based on chromosome conformation capture (3C) have greatly advanced our understanding of the three-dimensional (3D) organization of genomes, but are limited in resolution by their reliance on restriction enzymes. Here we describe a method for comprehensively mapping global chromatin contacts that uses DNaseI for chromatin fragmentation, leading to greatly improved efficiency and resolution. Coupling this method with DNA capture technology provides a high-throughput approach for targeted mapping of fine-scale chromatin architecture. We applied targeted DNase Hi-C to characterize the 3D organization of 1,030 lincRNA promoters in two human cell lines, and identified thousands of high-confidence lincRNA promoter-associated chromatin contacts at 1 kilobase pair (kbp) resolution. Detailed analysis of these contacts reveals that expression of lincRNAs is tightly controlled by complex mechanisms involving both super-enhancers and the polycomb repressive complex. Our results provide the first glimpse of the cell-type-specific 3D organization of lincRNA genes.
Project description:The landscape of human epigenome undergoes extensive changes during development, leading to distinct transcription programs in different cell types. It is however still not clear how the high-order genome organization reshapes in cellular differentiation. Using Hi-C, we compared the comprehensive 3D genome maps in human embryonic stem cells (ESCs) and two differentiated cell types at kilobase resolution. Consistent with previous reports, we found that the CTCF protein anchors long-range constitutive interactions that are invariant between different cell types. The most stable DNA contacts in ESC are between a few hundred genomic loci with strongest histone H3 lysine 27 tri-methylation (H3K27me3) binding, which plays a key role maintaining pluripotency by inhibiting key development genes. These repressive 3D chromatin structures are resolved in differentiated cells, accompanied by redistribution of H3K27me3 mark. Most surprisingly, we found that in human ESCs, DNA looping interactions are not enriched at enhancers, suggesting a stochastic nature of DNA looping interactions at ESC enhancers. This is in sharp contrast to differentiated cells, in which a majority of cell type specific DNA looping interactions are at enhancers, regardless of whether the enhancers are co-occupied by CTCF. Taken together, our analysis revealed a primitive enhancer-independent genome architecture in ESCs, which is consistent with the stem cell pluripotency and differentiation plasticity. Most of the stable DNA looping interactions associated with lineage-governing enhancers are created only during cell fate commitment.
Project description:The spatiotemporal control of 3D chromatin structure is fundamental for gene regulation, yet it remains challenging to obtain high-resolution chromatin interacting profiles at cis-regulatory elements (CREs) by chromatin conformation capture (3C)-based methods. Here, we describe the redesigned dCas9-based CAPTURE method for multiplexed, high-throughput and high-resolution analysis of locus-specific chromatin interactions. Using C-terminally biotinylated dCas9, endogenous biotin ligase and pooled sgRNAs, the new system enables quantitative analysis of the spatial configuration of a few to hundreds of enhancers or promoters in a single experiment, enabling systematic comparisons across CREs within and between gene clusters. We reveal the hierarchical structure of super-enhancers (SEs) and distinct modes of SE-gene interactions. Multiplexed capture of temporal dynamics of promoter-centric interactions establishes the instructive function of enhancer-promoter looping in transcriptional regulation during lineage differentiation. These applications illustrate the ability of multiplexed CAPTURE for decoding the organizational principles of genome structure and function.
Project description:The spatiotemporal control of 3D chromatin structure is fundamental for gene regulation, yet it remains challenging to obtain high-resolution chromatin interacting profiles at cis-regulatory elements (CREs) by chromatin conformation capture (3C)-based methods. Here, we describe the redesigned dCas9-based CAPTURE method for multiplexed, high-throughput and high-resolution analysis of locus-specific chromatin interactions. Using C-terminally biotinylated dCas9, endogenous biotin ligase and pooled sgRNAs, the new system enables quantitative analysis of the spatial configuration of a few to hundreds of enhancers or promoters in a single experiment, enabling systematic comparisons across CREs within and between gene clusters. We reveal the hierarchical structure of super-enhancers (SEs) and distinct modes of SE-gene interactions. Multiplexed capture of temporal dynamics of promoter-centric interactions establishes the instructive function of enhancer-promoter looping in transcriptional regulation during lineage differentiation. These applications illustrate the ability of multiplexed CAPTURE for decoding the organizational principles of genome structure and function.
Project description:The spatiotemporal control of 3D chromatin structure is fundamental for gene regulation, yet it remains challenging to obtain high-resolution chromatin interacting profiles at cis-regulatory elements (CREs) by chromatin conformation capture (3C)-based methods. Here, we describe the redesigned dCas9-based CAPTURE method for multiplexed, high-throughput and high-resolution analysis of locus-specific chromatin interactions. Using C-terminally biotinylated dCas9, endogenous biotin ligase and pooled sgRNAs, the new system enables quantitative analysis of the spatial configuration of a few to hundreds of enhancers or promoters in a single experiment, enabling systematic comparisons across CREs within and between gene clusters. Multiplexed analyses of erythroid super-enhancers (SEs) reveal SE hierarchical structure and distinct modes of SE-gene interactions. Multiplexed capture of temporal dynamics of promoter-centric interactions establishes the instructive function of enhancer-promoter looping in transcriptional regulation during lineage differentiation. These applications illustrate the ability of multiplexed CAPTURE for decoding the organizational principles of genome structure and function.
Project description:The spatiotemporal control of 3D chromatin structure is fundamental for gene regulation, yet it remains challenging to obtain high-resolution chromatin interacting profiles at cis-regulatory elements (CREs) by chromatin conformation capture (3C)-based methods. Here, we describe the redesigned dCas9-based CAPTURE method for multiplexed, high-throughput and high-resolution analysis of locus-specific chromatin interactions. Using C-terminally biotinylated dCas9, endogenous biotin ligase and pooled sgRNAs, the new system enables quantitative analysis of the spatial configuration of a few to hundreds of enhancers or promoters in a single experiment, enabling systematic comparisons across CREs within and between gene clusters. We reveal the hierarchical structure of super-enhancers (SEs) and distinct modes of SE-gene interactions. Multiplexed capture of temporal dynamics of promoter-centric interactions establishes the instructive function of enhancer-promoter looping in transcriptional regulation during lineage differentiation. These applications illustrate the ability of multiplexed CAPTURE for decoding the organizational principles of genome structure and function.