Chromatin accessibility to investigate the TF-chromatin information patterns encoded in the accessible genome
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE135074 | GEO | 2020/12/21
REPOSITORIES: GEO
Similar Datasets
Project description:Chromatin accessibility to investigate the TF-chromatin information patterns encoded in the accessible genome
| PRJNA557298 | ENA
Project description:How transcription factors (TFs) reprogram one cell lineage to another remains unclear. Here, we define chromatin accessibility changes induced by the proneural TF Ascl1 throughout conversion of fibroblasts into induced neuronal (iN) cells. Thousands of genomic loci are affected as early as 12 hours after Ascl1 induction. Surprisingly, over 80% of the accessibility changes occur between days 2 and 5 of the 3-week reprogramming process. This chromatin switch coincides with robust activation of endogenous neuronal TFs and nucleosome phasing of neuronal promoters and enhancers. Subsequent morphological and functional maturation of iN cells are accomplished with relatively little chromatin reconfiguration. Integrating chromatin accessibility and transcriptome changes, we built a network model of dynamic TF regulation during iN cell reprogramming, and identified Zfp238, Sox8 and Dlx3 as key TFs downstream of Ascl1. These results reveal a singular, coordinated epigenomic switch during direct reprogramming, in contrast to step-wise cell fate transitions in development.
2017-09-25 | GSE101397 | GEO
Project description:The nuclear lamina interacts with the genome through megabase-size lamina-associated domains (LADs). LADs have been identified in proximity labeling assays and recently by chromatin immunoprecipitation-sequencing (ChIP-seq) of A- and B-type lamins. LADs localize mainly to the nuclear periphery, they are gene-poor and largely heterochromatic. Here, we show that the mode of chromatin fragmentation for ChIP, namely either bath sonication (used to date for ChIP of nuclear lamins) or digestion with micrococcal nuclease (MNase) leads to the discovery of distinct sets of lamin-interacting domains (which we refer to as LiDs) with distinct gene content, histone composition enrichment and relationship to lamin B1-interacting domains. We find that total genome coverage by lamin A/C ('LMNA') LiDs identified in sonicated or MNase-digested chromatin is similar (~730 megabases). Over half of these domains, however, are uniquely detected in sonicated or MNase-digested chromatin. Whereas sonication-specific LMNA LiDs are gene-poor and devoid of a broad panel of histone modifications, MNase-specific LMNA LiDs are of higher gene density and are enriched in H3K9me3, H3K27me3 and in histone variant H2A.Z. Analysis of published LMNB1 LADs and of LMNB1 LiDs identified by ChIP-seq further shows that LMNA can associate with 'open' chromatin domains displaying euchromatin features which are not associated with LMNB1. The differential genetic and epigenetic properties of lamin-interacting chromatin domains indicate the existence of distinct LiD populations identifiable in different chromatin contexts, including nuclease-accessible 'open' regions presumably localized in the nuclear interior.
2015-03-24 | GSE57149 | GEO
Project description:Chromatin immunoprecipitation followed by massively parallel, high throughput sequencing (ChIP-seq) is the method of choice for identifying, on a genome-wide scale, the segments of DNA bound by specific transcription factors (TFs) or in chromatin with particular histone modifications. However, the quality of ChIP-seq datasets vary over a wide range, with a substantial fraction being of intermediate to poor quality. Such experimental variability can lead to many false positives or false negatives, impairing the ability to interpret the data. Thus, it is important to discern and control the factors that contribute to variation in ChIP-seq. In this study we focus on the sonication step to produce sheared chromatin, a variable controllable by the user and applicable to all ChIP-seq protocols. We systematically varied the amount of shearing of fixed chromatin from a mouse erythroid cell line, carefully measured the distribution of resultant fragment lengths using the Agilent Bioanalyzer 2100, and then immunoprecipitated these batches of chromatin using highly specific antibodies against either TAL1 or CTCF. We found that the level of sonication, which was affected by both the number of sonication cycles, as well as the starting cell number, had a pronounced impact on the quality of resulting ChIP-seq signals. Specifically, over-sonication led to degradation of quality (e.g. increased background and reduction in signal), while the impact of under-sonication of chromatin differed between the two transcription factors, leading to the loss of sites occupied by TAL1 but not those bound by CTCF. We leveraged these findings to produce a set of CTCF ChIPs-seq datasets in primary hematopoietic progenitor cells, including several rare cell types. Together, these results suggest that the amount of sonication is a key variable in success of ChIP-seq experiments, and that carefully monitoring the level of chromatin sonication is one way to improve ChIP-seq quality and reproducibility, which in turn facilitates low input ChIP-seq in rare cell types.
2020-10-14 | GSE159503 | GEO
Project description:Chromatin modifications provide additional context-dependence for DNA sequence-based gene regulation. Binding sites of the transcription factor (TF) and important tumour suppressor p53 are unusually diverse with regards to their chromatin accessibility and histone modifications, suggesting different modes of binding. Here, we show that the ability of p53 to open chromatin and activate its target genes is locally restricted by its cofactor Trim24. The histone-binding domains of Trim24 limits the role of p53 at closed chromatin but not at accessible chromatin where Trim24 is blocked by histone 3 methylation at lysine 4. In turn, p53 regulates gene expression as a function of the naïve chromatin state prior to activation. These findings establish a novel mode of gene regulation by p53 in closed chromatin and illustrate how histone modification sensing cofactors can bridge local chromatin state and TF potency.
2023-05-05 | PXD033674 | Pride
Project description:Estimation of synthetic accessibility score (SAScore) of drug-like molecules based on molecular complexity and fragment contributions. The fragment contributions are based on a 1M sample from PubChem and the molecular complexity is based on the presence/absence of non-standard structural features. It has been validated comparing the SAScore and the estimates of medicinal chemist experts for 40 molecules (r2 = 0.89).
Model Type: Predictive machine learning model.
Model Relevance: Estimation of synthetic accessibility score (SAScore)
Model Encoded by: Miquel Duran-Frigola (Ersilia)
Metadata Submitted in BioModels by: Zainab Ashimiyu-Abdusalam
Implementation of this model code by Ersilia is available here:
https://github.com/ersilia-os/eos9ei3
2024-07-18 | MODEL2407180004 | BioModels
Project description:Estimation of synthetic accessibility score (SAScore) of drug-like molecules based on molecular complexity and fragment contributions. The fragment contributions are based on a 1M sample from PubChem and the molecular complexity is based on the presence/absence of non-standard structural features. It has been validated comparing the SAScore and the estimates of medicinal chemist experts for 40 molecules (r2 = 0.89).
Model Type: Predictive machine learning model.
Model Relevance: Estimation of synthetic accessibility score (SAScore)
Model Encoded by: Miquel Duran-Frigola (Ersilia)
Metadata Submitted in BioModels by: Zainab Ashimiyu-Abdusalam
Implementation of this model code by Ersilia is available here:
https://github.com/ersilia-os/eos9ei3
2024-07-18 | MODEL2407180004 | BioModels
Project description:Glucocorticoid receptor (GR) is an essential transcription factor (TF), controlling metabolism, development and immune responses. SUMOylation regulates chromatin occupancy and target gene expression of GR in a locus-selective manner, but the mechanism of regulation has remained elusive. Here, we show using selective isolation of chromatin-associated proteins that the protein network around chromatin-bound GR is affected by SUMOylation, with several nuclear receptor coregulators and chromatin modifiers being more avidly associated with SUMOylation-deficient than SUMOylation competent GR. This difference is reflected in our chromatin accessibility and gene expression data, showing that the SUMOylation-deficient GR is more potent in opening chromatin at glucocorticoid-regulated enhancers and inducing expression of their target loci. Our results thus show that SUMOylation determines GR specificity by regulating the chromatin protein network and accessibility at GR-driven enhancers. We speculate that a similar mechanism is utilized by many other SUMOylated TFs.
2021-09-08 | PXD015183 | Pride
Project description:We mapped DNaseI hypersensitive sites (DHSs) and applied genomic footprinting to define in vivo transcription factor (TF) occupancy at nucleotide resolution across the A. thaliana genome in whole seedlings during heat- and light-response states. We find that trait-associated variation localizes within DHSs, and that extensive TF occupancy within protein-coding exons has shaped A. thaliana codon usage. Analysis of >700,000 TF footprints disclosed an extensive cis-regulatory lexicon, and enabled construction of large-scale TF cross-regulatory networks. Although the cis- and trans-regulatory repertoire is markedly distinct from mammals, the architecture of A. thaliana TF networks is strikingly similar to those of human. Analysis of the DHS landscape and TF network dynamics during heat shock and photomorphogenesis revealed thousands of conditionally-sensitive elements and enabled mapping of key regulatory circuits. Our results provide an extensive resource for understanding and enabling diverse aspects of A. thaliana biology. Chromatin accessibility profiling (Dnase I-seq) and RNA-seq of 7-day-old dark-grown seedlings exposed to 0hr light, 30min light, 3hr light or 24hr LD conditions. Chromatin accessibility profiling (Dnase I-seq) and RNA-seq of 7-day-old LD-grown seedlings treated with a brief sever heat shock or kept under control conditions. Replicates are included when available; controls and read-normalized samples (samples that were subsampled to the same read-depth) are also included here.
2013-12-15 | E-GEOD-53322 | biostudies-arrayexpress
Project description:Enhancers and silencers often depend on the same transcription factors (TFs) and are imperfectly distinguished from each other by genomic assays of TF binding or chromatin state. To identify sequence features that define enhancers and silencers, we assayed massively parallel reporter libraries of genomic sequences targeted by the photoreceptor TF CRX and found instances of enhancer, silencer, or no activity. Both enhancers and silencers contain more TF motifs than inactive sequences, but enhancers contain motifs from a more diverse collection of TFs. We developed a measure of information content that describes the number and diversity of motifs in a sequence and found that, while both enhancers and silencers depend on CRX motifs, enhancers have higher information content. Our results indicate that enhancers contain motifs for a diverse but degenerate collection of TFs, while silencers depend on a smaller and less diverse collection of TFs.
2021-01-30 | GSE165812 | GEO