UMI-4C for quantitative and targeted chromosomal contact profiling
ABSTRACT: We developed a targeted chromosome conformation capture (4C) approach that uses unique molecular identifiers (UMI) to derive high complexity quantitative chromosome contact profiles with controlled signal to noise ratios. We demonstrate that the method improves the sensitivity and specificity for detection of long-range chromosomal interactions, and that it allows the design of interaction screens with predictable statistical power. UMI-4C robustly quantifies contact intensity changes between cell types and conditions, opening the way toward incorporation of long-range interactions in quantitative models of gene regulation. We constructed UMI-4C profiles of 13 different genomic loci (viewpoints) in five different cell lines, in order to study the 3D chromatin contact maps of these selected loci. The coordinates for these viewpoints are: G1p1 chrX:48646542; baitG1_3_5kb chrX:48641393; bait_50kb chrX:48595987; bait_165kb chrX:48476525; ANK1 chr8:41654693; hbb_3HS chr11:5221346; hbb_HBB chr11:5248714; hbb_HBBP1_G1 chr11:5266532; HBB_HBE chr11:5292159; HBB_HS2 chr11:5301345; HBB_HS3 chr11:5306690; HBB_HS5 chr11:5313539; HBB_HBD chr11:5256597
Project description:We developed a targeted chromosome conformation capture (4C) approach that uses unique molecular identifiers (UMI) to derive high complexity quantitative chromosome contact profiles with controlled signal to noise ratios. We demonstrate that the method improves the sensitivity and specificity for detection of long-range chromosomal interactions, and that it allows the design of interaction screens with predictable statistical power. UMI-4C robustly quantifies contact intensity changes between cell types and conditions, opening the way toward incorporation of long-range interactions in quantitative models of gene regulation. Overall design: We constructed UMI-4C profiles of 5 different genomic loci (viewpoints) in one cell line under four different conditions, and two larval tissues, in order to study the 3D chromatin contact maps of these selected loci. The coordinates for these viewpoints are: BaitB1 chrX:1609904; BaitB2 chrX:1619649; BaitX1 chrX:158064; BaitX2 chrX:1829722; BaitX3 chrX:1945463
Project description:In Drosophila melanogaster, Hox genes are organized in an anterior and a posterior cluster, called Antennapedia complex and bithorax complex, located on the same chromosome arm and separated by 10 Mb of DNA. Both clusters are repressed by Polycomb group (PcG) proteins. Here, we show that genes of the two Hox complexes can interact within PcG bodies in the cell nucleus in tissues where they are corepressed. This colocalization increases during development and depends on PcG proteins. Hox gene contacts are part of a large gene interaction network that includes other PcG target genes. Moreover, they are conserved in the distantly related Drosophila virilis species, and mutations on one of the loci weaken silencing of genes in the other locus, resulting in the exacerbation of homeotic phenotypes in a sensitized genetic background. Thus, the three-dimensional organization of Polycomb target genes in the cell nucleus is an evolutionarily conserved phenomenon that stabilizes the maintenance of epigenetic gene silencing. Chromosome Conformation Capture on Chip (4C) was used to establish chromosomal interactions involving the Fab7 polycomb response element from the bithorax complex of Drosophila melanogaster. Larval brain and anterior discs from 3rd instar larvae were dissected to produce 2 replicate experiments with wild-type (WT-r1, WT-r2) and Fab-712 (F12-r1, F12-r2) fly lines. The 3C was performed as previously described (Hagege et al., 2007; Miele and Dekker, 2009) with the main differences being the use of DpnII (New England Biolabs), a 4 bp cutter restriction enzyme, and a fixation in 3% para-formaldehyde for 30 min, maximizing sensitivity and resolution of contact detection. The 4C DNA and DpnII digested genomic DNA (Control) samples were hybridized using a tiling array mapping the whole chromosome 3R which includes the antenapedia and bithorax hox clusters.
Project description:Drosophila Insulator proteins mediate long-range chromosomal interactions. ChIP-seq revealed that binding of insulator proteins to some specific DNA sites was regulated by poly(ADP-ribosyl)ation in S2 cells. Three insulator sites regulated by poly(ADP-ribosyl)ation were used as baits to map their distant interacting sites using 4C assay in control S2 cells. Mapping the chromosomal interactions of three specific insulator binding sites with 4C assay in control S2 cells.
Project description:MYC-PVT1 interaction is cell line specific Overall design: interactions were measeured UMI-4C by two technical replicates for two biological replicates (with 3 different anchor point, two primers for each anchor).
Project description:One of the strongest associated type 2 diabetes (T2D) loci reported to date resides within the TCF7L2 gene. Previous studies point to the T allele of rs7903146 in intron 3 as the causal variant at this locus. To aid in the identification of the actual gene(s) under the influence of this variant, we first generated a CRISPR/Cas9 mediated 1.4kb deletion of the genomic region harboring rs7903146 in the HCT116 cell line followed by global gene expression analysis (see experiment E-MTAB-4839). We then carried out high-throughput chromosome conformation capture assays in the HCT116 and NCM460 cell lines and in colon tissue in order to ascertain which of these perturbed genes promoters made consistent physical contact with the genomic region harboring the variant. To assess consistency and reproducibility we utilized two different techniques: Circularized Chromosome Conformation Capture (4C) and Capture C. In both types of assays, after preparing 3C libraries, our bait of interest was the region harboring rs7903146. Loci interacting with such bait are enriched for by inverse PCR in 4C and by oligonucleotide capture in capture C. 4C assays were carried out in the following samples: two on NCM460 cells (using different primer sets), one on HCT116 cells, one on HCT116 cells with a CRISPR/Cas9 mediated 1.4kb deletion of the genomic region harboring the SNP rs7903146, and one on colon tissue. Capture C assays were carried out in one sample each of the cell lines NCM 460 and HCT116. This experiment, coupled with the associated E-MTAB-4839, revealed just one gene, ACSL5, which resides in the same topologically associating domain as TCF7L2.
Project description:MYC-PVT1 interaction is cell line specific Overall design: Interactions were measured with UMI-4C by two technical replicates for two biological replicates (with 2 different anchor point, two primers for each anchor).
Project description:Insulin (INS) synthesis and secretion from pancreatic β cells are tightly regulated; their deregulation causes diabetes. Here we map INS-associated loci in human pancreatic islets by 4C and 3C techniques and show that the INS gene physically interacts with the SYT8 gene, located over 300 kb away. This interaction is elevated by glucose and accompanied by increases in SYT8 expression. Inactivation of the INS promoter by promoter-targeting siRNA reduces SYT8 gene expression. SYT8-INS interaction and SYT8 transcription are attenuated by CTCF depletion. Furthermore, SYT8 knockdown decreases insulin secretion in islets. These results reveal a non-redundant role for SYT8 in insulin secretion and indicate that the INS promoter acts from a distance to stimulate SYT8 transcription. This suggests a function for the INS promoter in coordinating insulin transcription and secretion through long-range regulation of SYT8 expression in human islets. Circular Chromosome Conformation Capture (4C)-Seq experiments to profile interactions of INS promoter in human pancreatic islets isolated from two donors: donor 1 and donor 2.
Project description:Mutations in the IDH1 and IDH2 genes encoding isocitrate dehydrogenases are frequent in human glioblastomas1 and cytogenetically normal acute myeloid leukemias (AML)2. These alterations are gain-of-function mutations in that they drive the synthesis of the “oncometabolite” R-2-hydroxyglutarate (2HG)3. It remains unclear how IDH1 and IDH2 mutations modify myeloid cell development and promote leukemogenesis. Here we report the characterization of conditional knock-in mice in which the most common IDH1 mutation, Idh1-R132H, is inserted into the endogenous murine Idh1 locus and is expressed in cells of the hematopoietic (Vav-KI) or more specifically in cells of the myeloid (LysM-KI) lineage. These mutants show increased numbers of early hematopoietic progenitors and develop splenomegaly and anemia with extramedullary hematopoiesis, suggesting a dysfunctional bone marrow niche. Furthermore, LysM-KI cells exhibit both hypermethylated histones and changes to DNA methylation similar to those observed in human IDH1/2-mutant AML. Thus, our study is the first to describe the generation of conditional Idh1-R132H-KI mice. Furthermore, our study is also the first report showing the induction of a leukemic DNA methylation signature in a modeled system and sheds light on the mechanistic links between IDH1 mutation and human AML. DNA methylation profiling in LSK cells from IDH1-R132H knock-in mice vs. control mice
Project description:To investigate the interaction landscape at the GILZ locus we performed 4C-seq in A549 (ATCC CCL-185) and U2OS cells stably expressing rat GR (Rogatsky et al. , Mol Cell Biol, 1997. 17(6): p. 3181-93.) upon hormone treatment (1.5 h, 1 M dexamethasone). Experiments were performed in two biological replicates using hg19 chrX:106,960,488-106,960,865 as a viewpoint.