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Gueno J, Borg M, Bourdareau S, Cossard G, Godfroy O, Lipinska A, Tirichine L, Cock J, Coelho S. Chromatin landscape associated with sexual differentiation in a UV sex determination system. Nucleic Acids Res 2022; 50:3307-3322. [PMID: 35253891 PMCID: PMC8989524 DOI: 10.1093/nar/gkac145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 02/15/2022] [Accepted: 03/04/2022] [Indexed: 12/12/2022] Open
Abstract
In many eukaryotes, such as dioicous mosses and many algae, sex is determined by UV sex chromosomes and is expressed during the haploid phase of the life cycle. In these species, the male and female developmental programs are initiated by the presence of the U- or V-specific regions of the sex chromosomes but, as in XY and ZW systems, sexual differentiation is largely driven by autosomal sex-biased gene expression. The mechanisms underlying the regulation of sex-biased expression of genes during sexual differentiation remain elusive. Here, we investigated the extent and nature of epigenomic changes associated with UV sexual differentiation in the brown alga Ectocarpus, a model UV system. Six histone modifications were quantified in near-isogenic lines, leading to the identification of 16 chromatin signatures across the genome. Chromatin signatures correlated with levels of gene expression and histone PTMs changes in males versus females occurred preferentially at genes involved in sex-specific pathways. Despite the absence of chromosome scale dosage compensation and the fact that UV sex chromosomes recombine across most of their length, the chromatin landscape of these chromosomes was remarkably different to that of autosomes. Hotspots of evolutionary young genes in the pseudoautosomal regions appear to drive the exceptional chromatin features of UV sex chromosomes.
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Affiliation(s)
- Josselin Gueno
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Michael Borg
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
| | - Simon Bourdareau
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Guillaume Cossard
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Olivier Godfroy
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Agnieszka Lipinska
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
| | - Leila Tirichine
- Nantes Universite, CNRS, US2B, UMR 6286, F-44000, Nantes, France
| | - J Mark Cock
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
| | - Susana M Coelho
- Sorbonne Université, UPMC Univ Paris 06, CNRS, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688 Roscoff, France
- Department of Algal Development and Evolution, Max Planck Institute for Biology Tübingen72076, Tübingen, Germany
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Mylonas C, Lee C, Auld AL, Cisse II, Boyer LA. A dual role for H2A.Z.1 in modulating the dynamics of RNA polymerase II initiation and elongation. Nat Struct Mol Biol 2021; 28:435-442. [PMID: 33972784 DOI: 10.1038/s41594-021-00589-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/06/2021] [Indexed: 02/03/2023]
Abstract
RNA polymerase II (RNAPII) pausing immediately downstream of the transcription start site is a critical rate-limiting step for the expression of most metazoan genes. During pause release, RNAPII encounters a highly conserved +1 H2A.Z nucleosome, yet how this histone variant contributes to transcription is poorly understood. Here, using an inducible protein degron system combined with genomic approaches and live cell super-resolution microscopy, we show that H2A.Z.1 modulates RNAPII dynamics across most genes in murine embryonic stem cells. Our quantitative analysis shows that H2A.Z.1 slows the rate of RNAPII pause release and consequently impacts negative elongation factor dynamics as well as nascent transcription. Consequently, H2A.Z.1 also impacts re-loading of the pre-initiation complex components TFIIB and TBP. Altogether, this work provides a critical mechanistic link between H2A.Z.1 and the proper induction of mammalian gene expression programs through the regulation of RNAPII dynamics and pause release.
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Affiliation(s)
- Constantine Mylonas
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Choongman Lee
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Alexander L Auld
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ibrahim I Cisse
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Laurie A Boyer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA. .,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Bourdareau S, Tirichine L, Lombard B, Loew D, Scornet D, Wu Y, Coelho SM, Cock JM. Histone modifications during the life cycle of the brown alga Ectocarpus. Genome Biol 2021; 22:12. [PMID: 33397407 PMCID: PMC7784034 DOI: 10.1186/s13059-020-02216-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 12/02/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Brown algae evolved complex multicellularity independently of the animal and land plant lineages and are the third most developmentally complex phylogenetic group on the planet. An understanding of developmental processes in this group is expected to provide important insights into the evolutionary events necessary for the emergence of complex multicellularity. Here, we focus on mechanisms of epigenetic regulation involving post-translational modifications of histone proteins. RESULTS A total of 47 histone post-translational modifications are identified, including a novel mark H2AZR38me1, but Ectocarpus lacks both H3K27me3 and the major polycomb complexes. ChIP-seq identifies modifications associated with transcription start sites and gene bodies of active genes and with transposons. H3K79me2 exhibits an unusual pattern, often marking large genomic regions spanning several genes. Transcription start sites of closely spaced, divergently transcribed gene pairs share a common nucleosome-depleted region and exhibit shared histone modification peaks. Overall, patterns of histone modifications are stable through the life cycle. Analysis of histone modifications at generation-biased genes identifies a correlation between the presence of specific chromatin marks and the level of gene expression. CONCLUSIONS The overview of histone post-translational modifications in the brown alga presented here will provide a foundation for future studies aimed at understanding the role of chromatin modifications in the regulation of brown algal genomes.
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Affiliation(s)
- Simon Bourdareau
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Leila Tirichine
- Université de Nantes, CNRS, UFIP, UMR 6286, F-44000, Nantes, France
| | - Bérangère Lombard
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Damarys Loew
- Institut Curie, PSL Research University, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, 26 rue d'Ulm, 75248, Paris, Cedex 05, France
| | - Delphine Scornet
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France
| | - Yue Wu
- Université de Nantes, CNRS, UFIP, UMR 6286, F-44000, Nantes, France
| | - Susana M Coelho
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France.
- Current address: Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, 72076, Tübingen, Germany.
| | - J Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, F-29688, Roscoff, France.
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Yamada N, Lai WKM, Farrell N, Pugh BF, Mahony S. Characterizing protein-DNA binding event subtypes in ChIP-exo data. Bioinformatics 2019; 35:903-913. [PMID: 30165373 DOI: 10.1093/bioinformatics/bty703] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 07/14/2018] [Accepted: 08/23/2018] [Indexed: 01/21/2023] Open
Abstract
MOTIVATION Regulatory proteins associate with the genome either by directly binding cognate DNA motifs or via protein-protein interactions with other regulators. Each recruitment mechanism may be associated with distinct motifs and may also result in distinct characteristic patterns in high-resolution protein-DNA binding assays. For example, the ChIP-exo protocol precisely characterizes protein-DNA crosslinking patterns by combining chromatin immunoprecipitation (ChIP) with 5' → 3' exonuclease digestion. Since different regulatory complexes will result in different protein-DNA crosslinking signatures, analysis of ChIP-exo tag enrichment patterns should enable detection of multiple protein-DNA binding modes for a given regulatory protein. However, current ChIP-exo analysis methods either treat all binding events as being of a uniform type or rely on motifs to cluster binding events into subtypes. RESULTS To systematically detect multiple protein-DNA interaction modes in a single ChIP-exo experiment, we introduce the ChIP-exo mixture model (ChExMix). ChExMix probabilistically models the genomic locations and subtype memberships of binding events using both ChIP-exo tag distribution patterns and DNA motifs. We demonstrate that ChExMix achieves accurate detection and classification of binding event subtypes using in silico mixed ChIP-exo data. We further demonstrate the unique analysis abilities of ChExMix using a collection of ChIP-exo experiments that profile the binding of key transcription factors in MCF-7 cells. In these data, ChExMix identifies possible recruitment mechanisms of FoxA1 and ERα, thus demonstrating that ChExMix can effectively stratify ChIP-exo binding events into biologically meaningful subtypes. AVAILABILITY AND IMPLEMENTATION ChExMix is available from https://github.com/seqcode/chexmix. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Naomi Yamada
- Department of Biochemistry & Molecular Biology and Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - William K M Lai
- Department of Biochemistry & Molecular Biology and Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Nina Farrell
- Department of Biochemistry & Molecular Biology and Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - B Franklin Pugh
- Department of Biochemistry & Molecular Biology and Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
| | - Shaun Mahony
- Department of Biochemistry & Molecular Biology and Center for Eukaryotic Gene Regulation, The Pennsylvania State University, University Park, PA, USA
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Ibn-Salem J, Andrade-Navarro MA. 7C: Computational Chromosome Conformation Capture by Correlation of ChIP-seq at CTCF motifs. BMC Genomics 2019; 20:777. [PMID: 31653198 PMCID: PMC6814980 DOI: 10.1186/s12864-019-6088-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/09/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Knowledge of the three-dimensional structure of the genome is necessary to understand how gene expression is regulated. Recent experimental techniques such as Hi-C or ChIA-PET measure long-range chromatin interactions genome-wide but are experimentally elaborate, have limited resolution and such data is only available for a limited number of cell types and tissues. RESULTS While ChIP-seq was not designed to detect chromatin interactions, the formaldehyde treatment in the ChIP-seq protocol cross-links proteins with each other and with DNA. Consequently, also regions that are not directly bound by the targeted TF but interact with the binding site via chromatin looping are co-immunoprecipitated and sequenced. This produces minor ChIP-seq signals at loop anchor regions close to the directly bound site. We use the position and shape of ChIP-seq signals around CTCF motif pairs to predict whether they interact or not. We implemented this approach in a prediction method, termed Computational Chromosome Conformation Capture by Correlation of ChIP-seq at CTCF motifs (7C). We applied 7C to all CTCF motif pairs within 1 Mb in the human genome and validated predicted interactions with high-resolution Hi-C and ChIA-PET. A single ChIP-seq experiment from known architectural proteins (CTCF, Rad21, Znf143) but also from other TFs (like TRIM22 or RUNX3) predicts loops accurately. Importantly, 7C predicts loops in cell types and for TF ChIP-seq datasets not used in training. CONCLUSION 7C predicts chromatin loops which can help to associate TF binding sites to regulated genes. Furthermore, profiling of hundreds of ChIP-seq datasets results in novel candidate factors functionally involved in chromatin looping. Our method is available as an R/Bioconductor package: http://bioconductor.org/packages/sevenC .
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Affiliation(s)
- Jonas Ibn-Salem
- Faculty of Biology, Johannes Gutenberg University of Mainz, 55128, Mainz, Germany.
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Venters BJ. Insights from resolving protein-DNA interactions at near base-pair resolution. Brief Funct Genomics 2019; 17:80-88. [PMID: 29211822 DOI: 10.1093/bfgp/elx043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
One of the central goals in molecular biology is to understand how cell-type-specific expression patterns arise through selective recruitment of RNA polymerase II (Pol II) to a subset of gene promoters. Pol II needs to be recruited to a precise genomic position at the proper time to produce messenger RNA from a DNA template. Ostensibly, transcription is a relatively simple cellular process; yet, experimentally measuring and then understanding the combinatorial possibilities of transcriptional regulators remain a daunting task. Since its introduction in 1985, chromatin immunoprecipitation (ChIP) has remained a key tool for investigating protein-DNA contacts in vivo. Over 30 years of intensive research using ChIP have provided numerous insights into mechanisms of gene regulation. As functional genomic technologies improve, they present new opportunities to address key biological questions. ChIP-exo is a refined version of ChIP-seq that significantly reduces background signal, while providing near base-pair mapping resolution for protein-DNA interactions. This review discusses the evolution of the ChIP assay over the years; the methodological differences between ChIP-seq, ChIP-exo and ChIP-nexus; and highlight new insights into epigenetic and transcriptional mechanisms that were uniquely enabled with the near base-pair resolution of ChIP-exo.
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Welch R, Chung D, Grass J, Landick R, Keles S. Data exploration, quality control and statistical analysis of ChIP-exo/nexus experiments. Nucleic Acids Res 2017; 45:e145. [PMID: 28911122 PMCID: PMC5587812 DOI: 10.1093/nar/gkx594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 07/12/2017] [Indexed: 01/03/2023] Open
Abstract
ChIP-exo/nexus experiments rely on innovative modifications of the commonly used ChIP-seq protocol for high resolution mapping of transcription factor binding sites. Although many aspects of the ChIP-exo data analysis are similar to those of ChIP-seq, these high throughput experiments pose a number of unique quality control and analysis challenges. We develop a novel statistical quality control pipeline and accompanying R/Bioconductor package, ChIPexoQual, to enable exploration and analysis of ChIP-exo and related experiments. ChIPexoQual evaluates a number of key issues including strand imbalance, library complexity, and signal enrichment of data. Assessment of these features are facilitated through diagnostic plots and summary statistics computed over regions of the genome with varying levels of coverage. We evaluated our QC pipeline with both large collections of public ChIP-exo/nexus data and multiple, new ChIP-exo datasets from Escherichia coli. ChIPexoQual analysis of these datasets resulted in guidelines for using these QC metrics across a wide range of sequencing depths and provided further insights for modelling ChIP-exo data.
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Affiliation(s)
- Rene Welch
- Department of Statistics, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Dongjun Chung
- Department of Public Health Sciences, Medical University of South Carolina, SC 29425, USA
| | - Jeffrey Grass
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726, USA.,Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Robert Landick
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI 53726, USA.,Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.,Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Sündüz Keles
- Department of Statistics, University of Wisconsin-Madison, Madison, WI 53706, USA.,Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI 53792, USA
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