Nucleosome positioning changes during cell reprogramming
Ontology highlight
ABSTRACT: Nucleosome positioning in a 2.3 Mb region of human chromosome 12 (chr12: 6,140,000-8,460,000) containing GAPDH and NANOG loci in human IMR90 fibroblasts (hFibs) and fibroblast-derived human induced pluripotent stem cell (hiPSCs).
Project description:3D structure of a 2.3 Mb region of human chromosome 12 (chr12: 6,140,000-8,460,000) containing GAPDH and NANOG loci in human IMR90 fibroblasts (hFibs) and fibroblast-derived human induced pluripotent stem cell (hiPSCs)
Project description:An incomplete view of the (epi)genetic events that drive melanoma initiation and progression has been a major barrier to rational development of effective therapeutics and prognostic diagnostics for melanoma patients. Recent approaches that integrate human melanoma genomic and transcriptomic data provide unprecedented opportunities to discover oncogenic melanoma drivers. One limitation, however, is that human melanoma genome exhibits a radically altered cytogenetic profile. Hence there is a need for biologically-meaningful approaches to identify and validate lesions that drive melanomagenesis. We combined comparative oncogenomic approaches with mouse modeling to identify new cancer genes/pathways that drive melanoma progression. Spontaneously acquired genetic alterations such as copy-number alterations and specific mutations in mouse tumors of defined genetic origin were identified and used to prioritize relevant lesions from the complex human melanoma genomes. This integrated effort confirmed the importance of several genes and pathways previously implicated in melanoma and identified new putative melanoma tumor suppressor genes. Genetic ablation of one such gene, Fes, cooperated with BRafv600E to accelerate melanomagenesis in mice. This comparative oncogenomic approach has therefore helped discover a series of novel melanoma tumor suppressor genes, including FES, with prognostic and therapeutic relevance in human melanoma.
Project description:Altered chromatin structure is a hallmark of cancer, and inappropriate regulation of chromatin structure may represent the origin of transformation. Several important studies have mapped human nucleosome distributions genome wide, but the genome-wide role of chromatin structure in cancer progression has not been addressed. We developed a MNase-Sequence Capture method, mTSS-seq, to map genome-wide nucleosome distribution in primary human lung and colon adenocarcinoma tissue. Here, we confirm that nucleosome redistribution is an early, widespread event in lung (LAC) and colon (CRC) adenocarcinoma. These altered nucleosome architectures are consistent between LAC and CRC patient samples indicating that they may serve as important early adenocarcinoma markers. We demonstrate that the nucleosome alterations are driven by the underlying DNA sequence and potentiate transcription factor binding. We conclude that DNA-directed nucleosome redistributions are widespread early in cancer progression. We have proposed an entirely new hierarchical model for chromatin-mediated genome regulation. â Nucleosome distribution mapping in primary patient tissue at all transcription start sites in the human genome Please note that two processed data files '4137N_ALLcombined.bed' and '4137T_ALLcombined.bed' (linked as Series supplementary file) are processed bed files combined from three 4137N_*_hiseq samples (total 6 raw data files) and three 4137T_*_hiseq samples (total 6 raw data files), respectively.
Project description:The aim of the experiment was to gain a higher resolution for specific regions of interest to complement the Hi-C results. Capture-C experiments were performed on four-inducible degrons for Scc1, Ringb, Ring1b-Scc1 and CTCF, and Tir1 control, always in triplicates (three biological replicates per condition).
Project description:Organoids were established from patients with endometrial diseases and DNA was extracted from low passage number and high passage number and compared with the primary tissue when available to investigate whether organoids retain the same genomic abnormalities and disease-associated features.
Project description:Phospholamban R14del mutazion (PLN-R14del) has been identified in a large family pedigree in which heterozygous carriers exhibited inherited dilated cardiomyopathy (DCM) and death by middle age. To better understand the causal link between the mutations in PLN and DCM pathology, we derived induced pluripotent stem cells from a DCM patient carrying the PLN R14del mutation. We showed that iPSC-derived cardiomyocytes recapitulated the DCM-specific phenotype and demonstrated that either TALEN-mediated genetic correction or combinatorial gene therapy resulted in phenotypic rescue. Our findings offer novel insights into the pathogenesis caused by mutant PLN and point to the development of potential new therapeutics of pathogenic genetic variants associated with inherited cardiomyopathies. Submitter confirms there are no patient privacy concerns with these data. iPSCs were derived from a female patient carrying a heterozygous mutation (R14del) in the PLN gene. Tree samples were analyzed: R14del-CMs (clone L2), corrected R14del-CMs (clone L2GC1) and corrected R14del-CMs (clone L2GC2)
Project description:DNA methylation in CpG context is fundamental to the epigenetic regulation of gene expression in high eukaryotes. Disorganization of methylation status is implicated in many diseases, cellular differentiation, imprinting, and other biological processes. Techniques that enrich for biologically relevant CpG-rich genomic regions are desired since, depending on the size of an oragnism's methylome, the depth of sequencing required to cover all CpGs can be prohibitively expensive. Currently, restriction-enzyme based Reduced Representation Bisulfite Sequencing and its modified protocols are widely used to study methylation differences. Recently, Agilent Technologies and Roche NimbleGen have aimed to both reduce sequencing costs and capture CpGs of known biological relevance by marketing in-solution custom-capture hybridization platforms. These three methods target approximately 10-13% of the human methylome. For each platform - restriction-enzyme based enhanced reduced representation (ERRBS), capture based Agilent SureSelect Methyl-seq (SSMethylseq), and capture based Roche NimbleGen SeqCap Epi CpGiant (CpGiant) - we used human lung fibroblast cell line IMR90 DNA to make libraries according to each protocol and sequenced to equivalent depth. Overall, SSMethylSeq and CpGiant covered >95% of their designed capture regions whereas ERRBS covered 70% of its expected MspI regions. Methylation levels were concordant across the platforms. The concordance of annotations of CpG units for genomic features, displayed roughly the same proportions of genomic features. SSMethylSeq and CpGiant are most similar and cover marginally more annotated regions than ERRBS. However, the number of CpG units shared by all methods was low, ~26% of any platform. We conclude that captured based methods are largely consistent in terms of covered CpG loci although ERRBS provides comparable data at a significantly reduced price. Furthermore, library preparation for ERRBS can be performed with as little as 75ngs of starting material, whereas micrograms are needed for the capture hybridization techniques. Libraries were made from human lung fibroblast cell line IMR90 DNA for each protocol of ERRBS, Agilent SureSelect Methyl-seq, Roche NimbleGen SeqCap Epi CpGiant, and WGBS, then sequenced as paired-end 100bp on an Illumina HiSeq 2500.
Project description:Gene splicing requires three basal genetic elements; the 3M-bM-^@M-^Y and 5M-bM-^@M-^Y splice sites and the branchpoint to which the 5M-bM-^@M-^Y intron termini is ligated to form a closed lariat during the splicing reaction. The 5M-bM-^@M-^Y and 3M-bM-^@M-^Y splice sites that define exon boundaries have been widely identified, revealing pervasive transcription and splicing of human genes. However, the locations of the third requisite element, the branchpoint, are still largely unknown. Here we employ two complementary approaches, targeted RNA sequencing and exoribonuclease digestion, to distil sequenced reads that traverse the lariat junction and, via non-conventional alignment, locate human branchpoint nucleotides. Alignments identify 88,748 branchpoints that correspond to 20% of known introns, with 76% supported by diagnostic sequence mismatch errors. This affords a first genome-wide analysis of branchpoints, describing their distribution, selection, and the existence of a diverse array of overlapping sequence motifs with distinct usage, evolutionary histories, and co-variation with distal splicing elements. The overlap of branchpoints with noncoding human genetic variation also indicates a notable contribution to disease. This annotation and analysis incorporates branchpoints into transcriptomic research and reflects a core role for this element in the regulatory code that governs gene splicing and expression. CaptureSeq identification of branchpoint nucleotides
Project description:To address how Csf3r and RUNX1 mutations in combination with CSF3 administration affect hematopoiesis in vivo, we performed serial transplantation experiments. Lineage-negative Csfr-d715 BM cell cells were lentivirally transduced with the patient specific RUNX1-D171N (RHD) mutant or an empty vector control. Primary recipients showed a pre-leukemic condition characterised by myeloblasts in the peripheral blood, but not overt AML. Upon serial transplantation, one of the Csfr-d715/RUNX1-D171N mutant mice, treated with CSF3, could repopulate secondary and tertiary recipients. Whole exome sequencing on these mice were performed to investigate whether these mice acquired an additional mutation. Enzymatically fragmented genomic DNA was used to construct sample libraries following the SeqCap EZ HyperPlusCap workflow User’s Guide version 1.0 (Roche). Unique, dual index adapters (Integrated DNA technologies) were used for ligation. After ligation of adapters and an amplification step, exome target sequences were captured using in-solution oligonucleotide baits (SeqCap EZ Developer Library mm9_exome_L2R_D02). Amplified captured sample libraries were paired-end sequenced on the HiSeq 2500 platform (Illumina).