scholarly journals Large-scale multi-omics analysis suggests specific roles for intragenic cohesin in transcriptional regulation

2021 ◽  
Author(s):  
Jiankang Wang ◽  
Masashige Bando ◽  
Katsuhiko Shirahige ◽  
Ryuichiro Nakato
Keyword(s):  
Transcriptional Regulation ◽  
Rna Polymerase Ii ◽  
Binding Sites ◽  
Large Scale ◽  
Gene Activation ◽  
Cell Types ◽  
Chromatin Interaction ◽  
Context Specific ◽  
Comprehensive Characterization

Cohesin, an essential protein complex for chromosome segregation, regulates transcription through a variety of mechanisms. It is not a trivial task to genome-widely assign the diverse cohesin functions. Moreover, the context-specific roles of cohesin-mediated interactions, especially on intragenic regions, have not been thoroughly investigated. Here we performed a comprehensive characterization of cohesin binding sites in several human cell types. We integrated epigenomic, transcriptomic and chromatin interaction data with and without transcriptional stimulation, to explore context-specific functions of intragenic cohesin related to gene activation. We identified a new subset of cohesin binding sites, decreased intragenic cohesin sites (DICs), which have a different function from previously known ones. The intron-enriched DICs were negatively correlated with transcriptional regulation: a subgroup of DICs were related to enhancer markers and paused RNA polymerase II, whereas others contributed to chromatin architecture. We implemented machine learning and successfully isolated DICs with distinct genomic features. We observed DICs in various cell types, including cells from cohesinopathy patients. These results suggest a previously unidentified function of cohesin at intragenic regions for transcription regulation.

scholarly journals TFregulomeR reveals transcription factors’ context-specific features and functions

2019 ◽  
Vol 48 (2) ◽  
pp. e10-e10 ◽  
Author(s):  
Quy Xiao Xuan Lin ◽  
Denis Thieffry ◽  
Sudhakar Jha ◽  
Touati Benoukraf
Keyword(s):  
Transcription Factors ◽  
Binding Sites ◽  
Leucine Zipper ◽  
Cell Types ◽  
Fine Tuning ◽  
A Cell ◽  
Context Specific ◽  
Gene Ontologies ◽  
Different Cell Types

Abstract Transcription factors (TFs) are sequence-specific DNA binding proteins, fine-tuning spatiotemporal gene expression. Since genomic occupancy of a TF is highly dynamic, it is crucial to study TF binding sites (TFBSs) in a cell-specific context. To date, thousands of ChIP-seq datasets have portrayed the genomic binding landscapes of numerous TFs in different cell types. Although these datasets can be browsed via several platforms, tools that can operate on that data flow are still lacking. Here, we introduce TFregulomeR (https://github.com/benoukraflab/TFregulomeR), an R-library linked to an up-to-date compendium of cistrome and methylome datasets, implemented with functionalities that facilitate integrative analyses. In particular, TFregulomeR enables the characterization of TF binding partners and cell-specific TFBSs, along with the study of TF’s functions in the context of different partnerships and DNA methylation levels. We demonstrated that TFs’ target gene ontologies can differ notably depending on their partners and, by re-analyzing well characterized TFs, we brought to light that numerous leucine zipper TFBSs derived from ChIP-seq experiments documented in current databases were inadequately characterized, due to the fact that their position weight matrices were assembled using a mixture of homodimer and heterodimer binding sites. Altogether, analyses of context-specific transcription regulation with TFregulomeR foster our understanding of regulatory network-dependent TF functions.

scholarly journals Simultaneous profiling of multiple chromatin proteins in the same cells

2021 ◽  
Author(s):  
Sneha Gopalan ◽  
Yuqing Wang ◽  
Nicholas W. Harper ◽  
Manuel Garber ◽  
Thomas G Fazzio
Keyword(s):  
Rna Polymerase Ii ◽  
Direct Analysis ◽  
Cell Types ◽  
Regulatory Elements ◽  
Genome Wide ◽  
Distinct Cell ◽  
Direct Measurements ◽  
Cell Type Specific ◽  
Chromatin Proteins

Methods derived from CUT&RUN and CUT&Tag enable genome-wide mapping of the localization of proteins on chromatin from as few as one cell. These and other mapping approaches focus on one protein at a time, preventing direct measurements of co-localization of different chromatin proteins in the same cells and requiring prioritization of targets where samples are limiting. Here we describe multi-CUT&Tag, an adaptation of CUT&Tag that overcomes these hurdles by using antibody-specific barcodes to simultaneously map multiple proteins in the same cells. Highly specific multi-CUT&Tag maps of histone marks and RNA Polymerase II uncovered sites of co-localization in the same cells, active and repressed genes, and candidate cis-regulatory elements. Single-cell multi-CUT&Tag profiling facilitated identification of distinct cell types from a mixed population and characterization of cell type-specific chromatin architecture. In sum, multi-CUT&Tag increases the information content per cell of epigenomic maps, facilitating direct analysis of the interplay of different proteins on chromatin.

scholarly journals The histone variant H2A.Z and chromatin remodeler BRAHMA act coordinately and antagonistically to regulate transcription and nucleosome dynamics in Arabidopsis

2018 ◽  
Author(s):  
E. Shannon Torres ◽  
Roger B. Deal
Keyword(s):  
Transcriptional Regulation ◽  
Transcription Factors ◽  
Binding Sites ◽  
Transcriptional Repression ◽  
Nucleosome Positioning ◽  
Chromatin Organization ◽  
Histone H2a ◽  
Nucleosome Dynamics ◽  
Environmentally Responsive ◽  
Context Specific

ABSTRACTPlants adapt to changes in their environment by regulating transcription and chromatin organization. The histone H2A variant H2A.Z and the SWI2/SNF2 ATPase BRAHMA have overlapping roles in positively and negatively regulating environmentally responsive genes in Arabidopsis, but the extent of this overlap was uncharacterized. Both have been associated with various changes in nucleosome positioning and stability in different contexts, but their specific roles in transcriptional regulation and chromatin organization need further characterization. We show that H2A.Z and BRM act both cooperatively and antagonistically to contribute directly to transcriptional repression and activation of genes involved in development and response to environmental stimuli. We identified 8 classes of genes that show distinct relationships between H2A.Z and BRM and their roles in transcription. We found that H2A.Z contributes to a range of different nucleosome properties, while BRM stabilizes nucleosomes where it binds and destabilizes and/or repositions flanking nucleosomes. H2A.Z and BRM contribute to +1 nucleosome destabilization, especially where they coordinately regulate transcription. We also found that at genes regulated by both BRM and H2A.Z, both factors overlap with the binding sites of light-regulated transcription factors PIF4, PIF5, and FRS9, and that some of the FRS9 binding sites are dependent on H2A.Z and BRM for accessibility. Collectively, we comprehensively characterized the antagonistic and cooperative contributions of H2A.Z and BRM to transcriptional regulation, and illuminated their interrelated roles in chromatin organization. The variability observed in their individual functions implies that both BRM and H2A.Z have more context-specific roles within diverse chromatin environments than previously assumed.

scholarly journals Pausing sites of RNA polymerase II on actively transcribed genes are enriched in DNA double-stranded breaks

2020 ◽  
Vol 295 (12) ◽  
pp. 3990-4000 ◽  
Author(s):  
Sandeep Singh ◽  
Karol Szlachta ◽  
Arkadi Manukyan ◽  
Heather M. Raimer ◽  
Manikarna Dinda ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcriptional Activation ◽  
Topoisomerase I ◽  
Cell Types ◽  
Dna Breaks ◽  
Transcription Start ◽  
Pol Ii ◽  
Transcription Start Sites

DNA double-stranded breaks (DSBs) are strongly associated with active transcription, and promoter-proximal pausing of RNA polymerase II (Pol II) is a critical step in transcriptional regulation. Mapping the distribution of DSBs along actively expressed genes and identifying the location of DSBs relative to pausing sites can provide mechanistic insights into transcriptional regulation. Using genome-wide DNA break mapping/sequencing techniques at single-nucleotide resolution in human cells, we found that DSBs are preferentially located around transcription start sites of highly transcribed and paused genes and that Pol II promoter-proximal pausing sites are enriched in DSBs. We observed that DSB frequency at pausing sites increases as the strength of pausing increases, regardless of whether the pausing sites are near or far from annotated transcription start sites. Inhibition of topoisomerase I and II by camptothecin and etoposide treatment, respectively, increased DSBs at the pausing sites as the concentrations of drugs increased, demonstrating the involvement of topoisomerases in DSB generation at the pausing sites. DNA breaks generated by topoisomerases are short-lived because of the religation activity of these enzymes, which these drugs inhibit; therefore, the observation of increased DSBs with increasing drug doses at pausing sites indicated active recruitment of topoisomerases to these sites. Furthermore, the enrichment and locations of DSBs at pausing sites were shared among different cell types, suggesting that Pol II promoter-proximal pausing is a common regulatory mechanism. Our findings support a model in which topoisomerases participate in Pol II promoter-proximal pausing and indicated that DSBs at pausing sites contribute to transcriptional activation.

scholarly journals Gene activation and repression by the glucocorticoid receptor are mediated by sequestering Ep300 and two modes of chromatin binding

2019 ◽  
Author(s):  
Avital Sarusi Portuguez ◽  
Ivana Grbesa ◽  
Moran Tal ◽  
Rachel Deitch ◽  
Dana Raz ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Sites ◽  
Gene Activation ◽  
Spatial Separation ◽  
Regulatory Elements ◽  
Chromatin Interaction ◽  
Chromatin Binding ◽  
Physiological Processes ◽  
Regulatory Loci ◽  
Open Question

ABSTRACTThe transcription factor glucocorticoid receptor (GR) is a key mediator of stress response and a broad range of physiological processes. How can GR rapidly activate the expression of some genes while repress others, remains an open question due to the challenge to associate GR binding sites (GBSs) to their distant gene targets. Mapping the full 3D scope of GR-responsive promoters using high-resolution 4C-seq unravelled spatial separation between chromatin interaction networks of GR-activated and repressed genes. Analysing GR binding sites and other regulatory loci in their functional 3D context revealed that GR sequesters the co-activator Ep300 from active non-GBS enhancers in both activated and repressed gene compartments. While this is sufficient for rapid gene repression, gene activation is countered by productive recruitment of Ep300 to GBS. Importantly, in GR-activated compartments Klf4 binding at non-GBS regulatory elements cluster in 3D with GBS and antagonizes GR activation. In addition, we revealed ROR and Rev-erb transcription factors as novel co-regulators for GR-mediated gene expression.

scholarly journals Comprehensive characterization of single-cell full-length isoforms in human and mouse with long-read sequencing

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Luyi Tian ◽  
Jafar S. Jabbari ◽  
Rachel Thijssen ◽  
Quentin Gouil ◽  
Shanika L. Amarasinghe ◽  
...  
Keyword(s):  
Ribosome Biogenesis ◽  
Single Cells ◽  
Transcript Level ◽  
Cell Types ◽  
Alternative Transcript ◽  
Long Read ◽  
Different Cell Types ◽  
Human And Mouse ◽  
Comprehensive Characterization

AbstractA modified Chromium 10x droplet-based protocol that subsamples cells for both short-read and long-read (nanopore) sequencing together with a new computational pipeline (FLAMES) is developed to enable isoform discovery, splicing analysis, and mutation detection in single cells. We identify thousands of unannotated isoforms and find conserved functional modules that are enriched for alternative transcript usage in different cell types and species, including ribosome biogenesis and mRNA splicing. Analysis at the transcript level allows data integration with scATAC-seq on individual promoters, improved correlation with protein expression data, and linked mutations known to confer drug resistance to transcriptome heterogeneity.

Discovery of Over-Represented Words in Intron 1s of Drosophila Ribosomal Protein Genes

2014 ◽  
Vol 707 ◽  
pp. 117-120
Author(s):  
Hui Min Li ◽  
Zhi Gang Yang ◽  
Dan Chen
Keyword(s):  
Transcriptional Regulation ◽  
Ribosomal Protein ◽  
Dna Sequences ◽  
Binding Sites ◽  
Regulatory Elements ◽  
Score Statistic ◽  
Z Score ◽  
Biological Functions ◽  
Ribosomal Protein Genes

Most of studies on transcriptional regulation mainly focus on upstream regions of genes. More and more recent researches indicate that introns may have important biological functions in transcription regulation of genes. The characterization of words in DNA sequences can be facilitated by the sequences’ functions. Using U-score and Z-score statistic, respectively, we extracted some over-represented words in intron 1s of ribosomal protein genes. A majority of them are accordance with known transcriptional factor binding sites and are potential regulatory elements. And, the detected over-represented words are more likely to form wider potential sequences and are denser in intron 1s of RP genes. We speculate the properties of these words may be associated with the transcriptional regulation of RP genes.

scholarly journals Open Targets Genetics: systematic identification of trait-associated genes using large-scale genetics and functional genomics

2020 ◽  
Vol 49 (D1) ◽  
pp. D1311-D1320 ◽  
Author(s):  
Maya Ghoussaini ◽  
Edward Mountjoy ◽  
Miguel Carmona ◽  
Gareth Peat ◽  
Ellen M Schmidt ◽  
...  
Keyword(s):  
Functional Genomics ◽  
Large Scale ◽  
Drug Repurposing ◽  
Cell Types ◽  
Chromatin Interaction ◽  
The Public ◽  
Wide Range ◽  
Causal Genes ◽  
Causal Variants ◽  
Systematic Identification

Abstract Open Targets Genetics (https://genetics.opentargets.org) is an open-access integrative resource that aggregates human GWAS and functional genomics data including gene expression, protein abundance, chromatin interaction and conformation data from a wide range of cell types and tissues to make robust connections between GWAS-associated loci, variants and likely causal genes. This enables systematic identification and prioritisation of likely causal variants and genes across all published trait-associated loci. In this paper, we describe the public resources we aggregate, the technology and analyses we use, and the functionality that the portal offers. Open Targets Genetics can be searched by variant, gene or study/phenotype. It offers tools that enable users to prioritise causal variants and genes at disease-associated loci and access systematic cross-disease and disease-molecular trait colocalization analysis across 92 cell types and tissues including the eQTL Catalogue. Data visualizations such as Manhattan-like plots, regional plots, credible sets overlap between studies and PheWAS plots enable users to explore GWAS signals in depth. The integrated data is made available through the web portal, for bulk download and via a GraphQL API, and the software is open source. Applications of this integrated data include identification of novel targets for drug discovery and drug repurposing.

scholarly journals Insights into the roles of local translation from the axonal transcriptome

Open Biology ◽  
2012 ◽  
Vol 2 (6) ◽  
pp. 120079 ◽  
Author(s):  
Alessia Deglincerti ◽  
Samie R. Jaffrey
Keyword(s):  
Large Scale ◽  
Local Translation ◽  
Axonal Translation ◽  
Comprehensive Characterization

Summary Much of our knowledge on the roles of intra-axonal translation derives from the characterization of a small number of individual mRNAs that were found to be localized in axons. However, two recent studies, using large-scale approaches to provide a more comprehensive characterization of the axonal transcriptome, have led to the discovery of thousands of axonal mRNAs. The apparent abundance of mRNAs in axons raises the possibility that local translation has many more functions than previously thought. Here, we review the recent studies that have profiled axonal mRNAs and discuss how the identification of axonal transcripts might point to unappreciated roles for local translation in axons.

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