1
|
Nowling RJ, Njoya K, Peters JG, Riehle MM. Prediction accuracy of regulatory elements from sequence varies by functional sequencing technique. Front Cell Infect Microbiol 2023; 13:1182567. [PMID: 37600946 PMCID: PMC10433755 DOI: 10.3389/fcimb.2023.1182567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 07/10/2023] [Indexed: 08/22/2023] Open
Abstract
Introduction Various sequencing based approaches are used to identify and characterize the activities of cis-regulatory elements in a genome-wide fashion. Some of these techniques rely on indirect markers such as histone modifications (ChIP-seq with histone antibodies) or chromatin accessibility (ATAC-seq, DNase-seq, FAIRE-seq), while other techniques use direct measures such as episomal assays measuring the enhancer properties of DNA sequences (STARR-seq) and direct measurement of the binding of transcription factors (ChIP-seq with transcription factor-specific antibodies). The activities of cis-regulatory elements such as enhancers, promoters, and repressors are determined by their sequence and secondary processes such as chromatin accessibility, DNA methylation, and bound histone markers. Methods Here, machine learning models are employed to evaluate the accuracy with which cis-regulatory elements identified by various commonly used sequencing techniques can be predicted by their underlying sequence alone to distinguish between cis-regulatory activity that is reflective of sequence content versus secondary processes. Results and discussion Models trained and evaluated on D. melanogaster sequences identified through DNase-seq and STARR-seq are significantly more accurate than models trained on sequences identified by H3K4me1, H3K4me3, and H3K27ac ChIP-seq, FAIRE-seq, and ATAC-seq. These results suggest that the activity detected by DNase-seq and STARR-seq can be largely explained by underlying DNA sequence, independent of secondary processes. Experimentally, a subset of DNase-seq and H3K4me1 ChIP-seq sequences were tested for enhancer activity using luciferase assays and compared with previous tests performed on STARR-seq sequences. The experimental data indicated that STARR-seq sequences are substantially enriched for enhancer-specific activity, while the DNase-seq and H3K4me1 ChIP-seq sequences are not. Taken together, these results indicate that the DNase-seq approach identifies a broad class of regulatory elements of which enhancers are a subset and the associated data are appropriate for training models for detecting regulatory activity from sequence alone, STARR-seq data are best for training enhancer-specific sequence models, and H3K4me1 ChIP-seq data are not well suited for training and evaluating sequence-based models for cis-regulatory element prediction.
Collapse
Affiliation(s)
- Ronald J. Nowling
- Electrical Engineering and Computer Science, Milwaukee School of Engineering, Milwaukee, WI, United States
| | - Kimani Njoya
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - John G. Peters
- Electrical Engineering and Computer Science, Milwaukee School of Engineering, Milwaukee, WI, United States
| | - Michelle M. Riehle
- Department of Microbiology and Immunology, Medical College of Wisconsin, Milwaukee, WI, United States
| |
Collapse
|
2
|
Ye B, Shen W, Li Y, Wang D, Zhang Y, Li P, Yin M, Wang Y, Xie D, Shi S, Yao T, Chen J, Xu P, Zhao Z. FAIRE-MS reveals mitotic retention of transcriptional regulators on a proteome-wide scale. FASEB J 2023; 37:e22724. [PMID: 36583687 DOI: 10.1096/fj.202201038rrr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 12/01/2022] [Accepted: 12/08/2022] [Indexed: 12/31/2022]
Abstract
Mitosis entails global and dramatic alterations, such as higher-order chromatin organization disruption, concomitant with global transcription downregulation. Cells reliably re-establishing gene expression patterns upon mitotic exit and maintaining cellular identities remain poorly understood. Previous studies indicated that certain transcription factors (TFs) remain associated with individual loci during mitosis and serve as mitotic bookmarkers. However, it is unclear which regulatory factors remain bound to the compacted mitotic chromosomes. We developed formaldehyde-assisted isolation of regulatory elements-coupled mass spectrometry (FAIRE-MS) that combines FAIRE-based open chromatin-associated protein pull-down and mass spectrometry (MS) to quantify the open chromatin-associated proteome during the interphase and mitosis. We identified 189 interphase and mitosis maintained (IM) regulatory factors using FAIRE-MS and found intrinsically disordered proteins and regions (IDP(R)s) are highly enriched, which plays a crucial role in liquid-liquid phase separation (LLPS) and chromatin organization during the cell cycle. Notably, in these IDP(R)s, we identified mitotic bookmarkers, such as CEBPB, HMGB1, and TFAP2A, and several factors, including MAX, HMGB3, hnRNP A2/B1, FUS, hnRNP D, and TIAL1, which are at least partially bound to the mitotic chromosome. Furthermore, it will be essential to study whether these IDP(R)s through LLPS helps cells transit from mitosis to the G1 phase during the cell cycle.
Collapse
Affiliation(s)
- Bingyu Ye
- Beijing Institute of Biotechnology, Beijing, China.,State Key Laboratory of Cell Differentiation and Regulation, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Wenlong Shen
- Beijing Institute of Biotechnology, Beijing, China
| | - Yanchang Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Institute of Lifeomics, Beijing, China
| | - Dong Wang
- Beijing Institute of Biotechnology, Beijing, China
| | - Yan Zhang
- Beijing Institute of Biotechnology, Beijing, China
| | - Ping Li
- Beijing Institute of Biotechnology, Beijing, China
| | - Man Yin
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yahao Wang
- Beijing Institute of Biotechnology, Beijing, China
| | - Dejian Xie
- Beijing Institute of Biotechnology, Beijing, China
| | - Shu Shi
- Beijing Institute of Biotechnology, Beijing, China
| | - Tao Yao
- Beijing Institute of Biotechnology, Beijing, China
| | - Juncai Chen
- Beijing Institute of Biotechnology, Beijing, China
| | - Ping Xu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Institute of Lifeomics, Beijing, China
| | - Zhihu Zhao
- Beijing Institute of Biotechnology, Beijing, China
| |
Collapse
|
3
|
Kumar S. SWI/SNF (BAF) complexes: From framework to a functional role in endothelial mechanotransduction. CURRENT TOPICS IN MEMBRANES 2021; 87:171-198. [PMID: 34696885 DOI: 10.1016/bs.ctm.2021.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Abstract
Endothelial cells (ECs) are constantly subjected to an array of mechanical cues, especially shear stress, due to their luminal placement in the blood vessels. Blood flow can regulate various aspects of endothelial biology and pathophysiology by regulating the endothelial processes at the transcriptomic, proteomic, miRNomic, metabolomics, and epigenomic levels. ECs sense, respond, and adapt to altered blood flow patterns and shear profiles by specialized mechanisms of mechanosensing and mechanotransduction, resulting in qualitative and quantitative differences in their gene expression. Chromatin-regulatory proteins can regulate transcriptional activation by modifying the organization of nucleosomes at promoters, enhancers, silencers, insulators, and locus control regions. Recent research efforts have illustrated that SWI/SNF (SWItch/Sucrose Non-Fermentable) or BRG1/BRM-associated factor (BAF) complex regulates DNA accessibility and chromatin structure. Since the discovery, the gene-regulatory mechanisms of the BAF complex associated with chromatin remodeling have been intensively studied to investigate its role in diverse disease phenotypes. Thus far, it is evident that (1) the SWI/SNF complex broadly regulates the activity of transcriptional enhancers to control lineage-specific differentiation and (2) mutations in the BAF complex proteins lead to developmental disorders and cancers. It is unclear if blood flow can modulate the activity of SWI/SNF complex to regulate EC differentiation and reprogramming. This review emphasizes the integrative role of SWI/SNF complex from a structural and functional standpoint with a special reference to cardiovascular diseases (CVDs). The review also highlights how regulation of this complex by blood flow can lead to the discovery of new therapeutic interventions for the treatment of endothelial dysfunction in vascular diseases.
Collapse
Affiliation(s)
- Sandeep Kumar
- Wallace H. Coulter Department of Biomedical Engineering at Emory University and Georgia Institute of Technology, Atlanta, GA, United States.
| |
Collapse
|
4
|
Horisawa K, Udono M, Ueno K, Ohkawa Y, Nagasaki M, Sekiya S, Suzuki A. The Dynamics of Transcriptional Activation by Hepatic Reprogramming Factors. Mol Cell 2020; 79:660-676.e8. [PMID: 32755593 DOI: 10.1016/j.molcel.2020.07.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/18/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
Abstract
Specific combinations of two transcription factors (Hnf4α plus Foxa1, Foxa2, or Foxa3) can induce direct conversion of mouse fibroblasts into hepatocyte-like cells. However, the molecular mechanisms underlying hepatic reprogramming are largely unknown. Here, we show that the Foxa protein family members and Hnf4α sequentially and cooperatively bind to chromatin to activate liver-specific gene expression. Although all Foxa proteins bind to and open regions of closed chromatin as pioneer factors, Foxa3 has the unique potential of transferring from the distal to proximal regions of the transcription start site of target genes, binding RNA polymerase II, and co-traversing target genes. These distinctive characteristics of Foxa3 are essential for inducing the hepatic fate in fibroblasts. Similar functional coupling of transcription factors to RNA polymerase II may occur in other contexts whereby transcriptional activation can induce cell differentiation.
Collapse
Affiliation(s)
- Kenichi Horisawa
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Miyako Udono
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Kazuko Ueno
- Genome Medical Science Project, National Center for Global Health and Medicine, Tokyo 162-8655, Japan
| | - Yasuyuki Ohkawa
- Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Masao Nagasaki
- Center for Genomic Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan; Human Biosciences Unit for the Top Global Course, Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto 606-8507, Japan
| | - Sayaka Sekiya
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Atsushi Suzuki
- Division of Organogenesis and Regeneration, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan.
| |
Collapse
|
5
|
Klein DC, Hainer SJ. Genomic methods in profiling DNA accessibility and factor localization. Chromosome Res 2019; 28:69-85. [PMID: 31776829 PMCID: PMC7125251 DOI: 10.1007/s10577-019-09619-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 12/24/2022]
Abstract
Recent advancements in next-generation sequencing technologies and accompanying reductions in cost have led to an explosion of techniques to examine DNA accessibility and protein localization on chromatin genome-wide. Generally, accessible regions of chromatin are permissive for factor binding and are therefore hotspots for regulation of gene expression; conversely, genomic regions that are highly occupied by histone proteins are not permissive for factor binding and are less likely to be active regulatory regions. Identifying regions of differential accessibility can be useful to uncover putative gene regulatory regions, such as enhancers, promoters, and insulators. In addition, DNA-binding proteins, such as transcription factors that preferentially bind certain DNA sequences and histone proteins that form the core of the nucleosome, play essential roles in all DNA-templated processes. Determining the genomic localization of chromatin-bound proteins is therefore essential in determining functional roles, sequence motifs important for factor binding, and regulatory networks controlling gene expression. In this review, we discuss techniques for determining DNA accessibility and nucleosome positioning (DNase-seq, FAIRE-seq, MNase-seq, and ATAC-seq) and techniques for detecting and functionally characterizing chromatin-bound proteins (ChIP-seq, DamID, and CUT&RUN). These methods have been optimized to varying degrees of resolution, specificity, and ease of use. Here, we outline some advantages and disadvantages of these techniques, their general protocols, and a brief discussion of their development. Together, these complimentary approaches have provided an unparalleled view of chromatin architecture and functional gene regulation.
Collapse
Affiliation(s)
- David C Klein
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Sarah J Hainer
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
| |
Collapse
|
6
|
Sun Y, Miao N, Sun T. Detect accessible chromatin using ATAC-sequencing, from principle to applications. Hereditas 2019; 156:29. [PMID: 31427911 PMCID: PMC6696680 DOI: 10.1186/s41065-019-0105-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/12/2019] [Indexed: 02/07/2023] Open
Abstract
Background Chromatin accessibility is crucial for gene expression regulation in specific cells and in multiple biological processes. Assay for Transposase Accessible Chromatin with high-throughput sequencing (ATAC-seq) is an effective way to reveal chromatin accessibility at a genome-wide level. Through ATAC-seq, produced reads from a small number of cells reflect accessible regions that correspond to nucleosome positioning and transcription factor binding sites, due to probing hyperactive Tn5 transposase to DNA sequence. Conclusion In this review, we summarize both principle and features of ATAC-seq, highlight its applications in basic and clinical research. ATAC-seq has generated comprehensive chromatin accessible maps, and is becoming a powerful tool to understand dynamic gene expression regulation in stem cells, early embryos and tumors.
Collapse
Affiliation(s)
- Yuanyuan Sun
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, 668 Jimei Road, Xiamen, 361021 Fujian China
| | - Nan Miao
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, 668 Jimei Road, Xiamen, 361021 Fujian China
| | - Tao Sun
- Center for Precision Medicine, School of Medicine and School of Biomedical Sciences, Huaqiao University, 668 Jimei Road, Xiamen, 361021 Fujian China
| |
Collapse
|
7
|
Schlesinger S, Meshorer E. Open Chromatin, Epigenetic Plasticity, and Nuclear Organization in Pluripotency. Dev Cell 2019; 48:135-150. [DOI: 10.1016/j.devcel.2019.01.003] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 10/30/2018] [Accepted: 12/31/2018] [Indexed: 12/27/2022]
|
8
|
Li T, Jia L, Cao Y, Chen Q, Li C. OCEAN-C: mapping hubs of open chromatin interactions across the genome reveals gene regulatory networks. Genome Biol 2018; 19:54. [PMID: 29690904 PMCID: PMC5926533 DOI: 10.1186/s13059-018-1430-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 03/30/2018] [Indexed: 01/26/2023] Open
Abstract
We develop a method called open chromatin enrichment and network Hi-C (OCEAN-C) for antibody-independent mapping of global open chromatin interactions. By integrating FAIRE-seq and Hi-C, OCEAN-C detects open chromatin interactions enriched by active cis-regulatory elements. We identify more than 10,000 hubs of open chromatin interactions (HOCIs) in human cells, which are mainly active promoters and enhancers bound by many DNA-binding proteins and form interaction networks crucial for gene transcription. In addition to identifying large-scale topological structures, including topologically associated domains and A/B compartments, OCEAN-C can detect HOCI-mediated chromatin interactions that are strongly associated with gene expression, super-enhancers, and broad H3K4me3 domains.
Collapse
Affiliation(s)
- Tingting Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies; School of Life Sciences, Peking University, Beijing, 100871, China.,State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Institute of Basic Medical Sciences, Beijing, 100850, China
| | - Lumeng Jia
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies; School of Life Sciences, Peking University, Beijing, 100871, China
| | - Yong Cao
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies; School of Life Sciences, Peking University, Beijing, 100871, China
| | - Qing Chen
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies; School of Life Sciences, Peking University, Beijing, 100871, China
| | - Cheng Li
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies; School of Life Sciences, Peking University, Beijing, 100871, China. .,Center for Statistical Science; Center for Bioinformatics, Peking University, Beijing, 100871, China.
| |
Collapse
|
9
|
Williams EO, Taylor AK, Bell EL, Lim R, Kim DM, Guarente L. Sirtuin 1 Promotes Deacetylation of Oct4 and Maintenance of Naive Pluripotency. Cell Rep 2017; 17:809-820. [PMID: 27732856 DOI: 10.1016/j.celrep.2016.09.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/14/2016] [Accepted: 09/15/2016] [Indexed: 01/07/2023] Open
Abstract
The enhancer landscape is dramatically restructured as naive preimplantation epiblasts transition to the post-implantation state of primed pluripotency. A key factor in this process is Otx2, which is upregulated during the early stages of this transition and ultimately recruits Oct4 to a different set of enhancers. In this study, we discover that the acetylation status of Oct4 regulates the induction of the primed pluripotency gene network. Maintenance of the naive state requires the NAD-dependent deacetylase, SirT1, which deacetylates Oct4. The activity of SirT1 is reduced during the naive-to-primed transition; Oct4 becomes hyper-acetylated and binds to an Otx2 enhancer to induce Otx2 expression. Induction of Otx2 causes the reorganization of acetylated Oct4 and results in the induction of the primed pluripotency gene network. Regulation of Oct4 by SirT1 may link stem cell development to environmental conditions, and it may provide strategies to manipulate epiblast cell state.
Collapse
Affiliation(s)
- Eric O Williams
- Glenn Laboratory for the Science of Aging and the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Amy K Taylor
- Glenn Laboratory for the Science of Aging and the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Eric L Bell
- Glenn Laboratory for the Science of Aging and the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Rachelle Lim
- Glenn Laboratory for the Science of Aging and the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Daniel M Kim
- Glenn Laboratory for the Science of Aging and the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Leonard Guarente
- Glenn Laboratory for the Science of Aging and the Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| |
Collapse
|
10
|
Fishwick C, Higgins J, Percival-Alwyn L, Hustler A, Pearson J, Bastkowski S, Moxon S, Swarbreck D, Greenman CD, Southgate J. Heterarchy of transcription factors driving basal and luminal cell phenotypes in human urothelium. Cell Death Differ 2017; 24:809-818. [PMID: 28282036 PMCID: PMC5423105 DOI: 10.1038/cdd.2017.10] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 02/06/2023] Open
Abstract
Cell differentiation is affected by complex networks of transcription factors that co-ordinate re-organisation of the chromatin landscape. The hierarchies of these relationships can be difficult to dissect. During in vitro differentiation of normal human uro-epithelial cells, formaldehyde-assisted isolation of regulatory elements (FAIRE-seq) and RNA-seq was used to identify alterations in chromatin accessibility and gene expression changes following activation of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) as a differentiation-initiating event. Regions of chromatin identified by FAIRE-seq, as having altered accessibility during differentiation, were found to be enriched with sequence-specific binding motifs for transcription factors predicted to be involved in driving basal and differentiated urothelial cell phenotypes, including forkhead box A1 (FOXA1), P63, GRHL2, CTCF and GATA-binding protein 3 (GATA3). In addition, co-occurrence of GATA3 motifs was observed within subsets of differentiation-specific peaks containing P63 or FOXA1. Changes in abundance of GRHL2, GATA3 and P63 were observed in immunoblots of chromatin-enriched extracts. Transient siRNA knockdown of P63 revealed that P63 favoured a basal-like phenotype by inhibiting differentiation and promoting expression of basal marker genes. GATA3 siRNA prevented differentiation-associated downregulation of P63 protein and transcript, and demonstrated positive feedback of GATA3 on PPARG transcript, but showed no effect on FOXA1 transcript or protein expression. This approach indicates that as a transcriptionally regulated programme, urothelial differentiation operates as a heterarchy, wherein GATA3 is able to co-operate with FOXA1 to drive expression of luminal marker genes, but that P63 has potential to transrepress expression of the same genes.
Collapse
Affiliation(s)
- Carl Fishwick
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York YO10 5DD, UK
| | - Janet Higgins
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | | | - Arianna Hustler
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York YO10 5DD, UK
| | - Joanna Pearson
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York YO10 5DD, UK
| | | | - Simon Moxon
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | - David Swarbreck
- Earlham Institute, Norwich Research Park, Norwich NR4 7UZ, UK
| | - Chris D Greenman
- School of Computing Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jennifer Southgate
- Jack Birch Unit for Molecular Carcinogenesis, Department of Biology, University of York, York YO10 5DD, UK
| |
Collapse
|
11
|
DNA methylation is dispensable for changes in global chromatin architecture but required for chromocentre formation in early stem cell differentiation. Chromosoma 2017; 126:605-614. [PMID: 28084535 DOI: 10.1007/s00412-017-0625-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 12/21/2016] [Accepted: 01/02/2017] [Indexed: 01/05/2023]
Abstract
Epiblast stem cells (EpiSCs), which are pluripotent cells isolated from early post-implantation mouse embryos (E5.5), show both similarities and differences compared to mouse embryonic stem cells (mESCs), isolated earlier from the inner cell mass (ICM) of the E3.5 embryo. Previously, we have observed that while chromatin is very dispersed in E3.5 ICM, compact chromatin domains and chromocentres appear in E5.5 epiblasts after embryo implantation. Given that the observed chromatin re-organization in E5.5 epiblasts coincides with an increase in DNA methylation, in this study, we aimed to examine the role of DNA methylation in chromatin re-organization during the in vitro conversion of ESCs to EpiSCs. The requirement for DNA methylation was determined by converting both wild-type and DNA methylation-deficient ESCs to EpiSCs, followed by structural analysis with electron spectroscopic imaging (ESI). We show that the chromatin re-organization which occurs in vivo can be re-capitulated in vitro during the ESC to EpiSC conversion. Indeed, after 7 days in EpiSC media, compact chromatin domains begin to appear throughout the nuclear volume, creating a chromatin organization similar to E5 epiblasts and embryo-derived EpiSCs. Our data demonstrate that DNA methylation is dispensable for this global chromatin re-organization but required for the compaction of pericentromeric chromatin into chromocentres.
Collapse
|
12
|
Gomez NC, Hepperla AJ, Dumitru R, Simon JM, Fang F, Davis IJ. Widespread Chromatin Accessibility at Repetitive Elements Links Stem Cells with Human Cancer. Cell Rep 2016; 17:1607-1620. [PMID: 27806299 PMCID: PMC5267842 DOI: 10.1016/j.celrep.2016.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 06/02/2016] [Accepted: 10/02/2016] [Indexed: 11/15/2022] Open
Abstract
Chromatin regulation is critical for differentiation and disease. However, features linking the chromatin environment of stem cells with disease remain largely unknown. We explored chromatin accessibility in embryonic and multipotent stem cells and unexpectedly identified widespread chromatin accessibility at repetitive elements. Integrating genomic and biochemical approaches, we demonstrate that these sites of increased accessibility are associated with well-positioned nucleosomes marked by distinct histone modifications. Differentiation is accompanied by chromatin remodeling at repetitive elements associated with altered expression of genes in relevant developmental pathways. Remarkably, we found that the chromatin environment of Ewing sarcoma, a mesenchymally derived tumor, is shared with primary mesenchymal stem cells (MSCs). Accessibility at repetitive elements in MSCs offers a permissive environment that is exploited by the critical oncogene responsible for this cancer. Our data demonstrate that stem cells harbor a unique chromatin landscape characterized by accessibility at repetitive elements, a feature associated with differentiation and oncogenesis.
Collapse
Affiliation(s)
- Nicholas C Gomez
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Austin J Hepperla
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Raluca Dumitru
- Department of Genetics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Human Pluripotent Stem Cell Core Facility, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeremy M Simon
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Fang Fang
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ian J Davis
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Department of Genetics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA; Department of Pediatrics, University of North Carolina, Chapel Hill, Chapel Hill, NC 27599, USA.
| |
Collapse
|
13
|
Hardy K, Wu F, Tu W, Zafar A, Boulding T, McCuaig R, Sutton CR, Theodoratos A, Rao S. Identification of chromatin accessibility domains in human breast cancer stem cells. Nucleus 2016; 7:50-67. [PMID: 26962893 PMCID: PMC4916893 DOI: 10.1080/19491034.2016.1150392] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Epithelial-to-mesenchymal transition (EMT) is physiological in embryogenesis and wound healing but also associated with the formation of cancer stem cells (CSCs). Many EMT signaling pathways are implicated in CSC formation, but the precise underlying mechanisms of CSC formation remain elusive. We have previously demonstrated that PKC is critical for EMT induction and CSC formation in inducible breast EMT/CSC models. Here, we used formaldehyde-assisted isolation of regulatory elements-sequencing (FAIRE-seq) to investigate DNA accessibility changes after PKC activation and determine how they influence EMT and CSC formation. During EMT, DNA accessibility principally increased in regions distant from transcription start sites, low in CpG content, and enriched with chromatin enhancer marks. ChIP-sequencing revealed that a subset of these regions changed from poised to active enhancers upon stimulation, with some even more acteylated in CSCs. While regions with increased accessibility were enriched for FOX, AP-1, TEAD, and TFAP2 motifs, those containing FOX and AP-1 motif were associated with increased expression of CSC-associated genes, while those with TFAP2 were associated with genes with increased expression in non-CSCs. Silencing of 2 members of the FOX family, FOXN2 and FOXQ1, repressed CSCs and the mesenchymal phenotype and inhibited the CSC gene signature. These novel, PKC-induced DNA accessibility regions help explain how the epigenomic plasticity of cells undergoing EMT leads to CSC gene activation.
Collapse
Affiliation(s)
- K Hardy
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - F Wu
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - W Tu
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - A Zafar
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - T Boulding
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - R McCuaig
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - C R Sutton
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| | - A Theodoratos
- b JCSMR, Australian National University , Canberra, Australia
| | - S Rao
- a HRI, Faculty of ESTeM, University of Canberra , Bruce , Australia
| |
Collapse
|
14
|
Li L, Chen Z, Zhang L, Liu G, Hua J, Jia L, Liao M. Genome-wide targets identification of "core" pluripotency transcription factors with integrated features in human embryonic stem cells. MOLECULAR BIOSYSTEMS 2016; 12:1324-32. [PMID: 26912333 DOI: 10.1039/c6mb00006a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Embryonic stem cells (ESCs) play an important role in developmental biology which is still lacking clear molecular mechanisms. The "core" transcription factors (TFs) including OCT4, SOX2 and NANOG are essential for maintaining the stemness of ESCs. But the downstream targets of these "core" TFs are still ambiguous. Based on support vector machine (SVM) technology, this study develops a label method algorithm (LMA) for genome-wide target identification of "core" TFs in humans, which eliminates the need for negative training samples. This method integrates histone modifications and TF binding motifs as identification features. Compared with a previous mapping-convergence (M-C) algorithm, the LMA can provide more stable and reliable predictions. 4796, 3166 and 4384 target genes of OCT4, SOX2 and NANOG, respectively, were identified with the LMA model. Then verifications of the predicted targets were carried out based on their functional consistency and their connection degree in networks from a computational system biology perspective. The results showed that the targets of "core" TFs present higher gene functional similarity and closer connection distance than background levels.
Collapse
Affiliation(s)
- Leijie Li
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi 712100, China.
| | | | | | | | | | | | | |
Collapse
|
15
|
Sun J, Rockowitz S, Chauss D, Wang P, Kantorow M, Zheng D, Cvekl A. Chromatin features, RNA polymerase II and the comparative expression of lens genes encoding crystallins, transcription factors, and autophagy mediators. Mol Vis 2015; 21:955-73. [PMID: 26330747 PMCID: PMC4551281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/26/2015] [Indexed: 10/26/2022] Open
Abstract
PURPOSE Gene expression correlates with local chromatin structure. Our studies have mapped histone post-translational modifications, RNA polymerase II (pol II), and transcription factor Pax6 in lens chromatin. These data represent the first genome-wide insights into the relationship between lens chromatin structure and lens transcriptomes and serve as an excellent source for additional data analysis and refinement. The principal lens proteins, the crystallins, are encoded by predominantly expressed mRNAs; however, the regulatory mechanisms underlying their high expression in the lens remain poorly understood. METHODS The formaldehyde-assisted identification of regulatory regions (FAIRE-Seq) was employed to analyze newborn lens chromatin. ChIP-seq and RNA-seq data published earlier (GSE66961) have been used to assist in FAIRE-seq data interpretation. RNA transcriptomes from murine lens epithelium, lens fibers, erythrocytes, forebrain, liver, neurons, and pancreas were compared to establish the gene expression levels of the most abundant mRNAs versus median gene expression across other differentiated cells. RESULTS Normalized RNA expression data from multiple tissues show that crystallins rank among the most highly expressed genes in mammalian cells. These findings correlate with the extremely high abundance of pol II all across the crystallin loci, including crystallin genes clustered on chromosomes 1 and 5, as well as within regions of "open" chromatin, as identified by FAIRE-seq. The expression levels of mRNAs encoding DNA-binding transcription factors (e.g., Foxe3, Hsf4, Maf, Pax6, Prox1, Sox1, and Tfap2a) revealed that their transcripts form "clusters" of abundant mRNAs in either lens fibers or lens epithelium. The expression of three autophagy regulatory mRNAs, encoding Tfeb, FoxO1, and Hif1α, was found within a group of lens preferentially expressed transcription factors compared to the E12.5 forebrain. CONCLUSIONS This study reveals novel features of lens chromatin, including the remarkably high abundance of pol II at the crystallin loci that exhibit features of "open" chromatin. Hsf4 ranks among the most abundant fiber cell-preferred DNA-binding transcription factors. Notable transcripts, including Atf4, Ctcf, E2F4, Hey1, Hmgb1, Mycn, RXRβ, Smad4, Sp1, and Taf1 (transcription factors) and Ctsd, Gabarapl1, and Park7 (autophagy regulators) have been identified with high levels of expression in lens fibers, which suggests specific roles in lens fiber cell terminal differentiation.
Collapse
Affiliation(s)
- Jian Sun
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY,Department of Genetics, Albert Einstein College of Medicine, Bronx, NY
| | - Shira Rockowitz
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY
| | - Daniel Chauss
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL
| | - Ping Wang
- Department of Neurology, Albert Einstein College of Medicine, Bronx, NY
| | - Marc Kantorow
- Department of Biomedical Science, Florida Atlantic University, Boca Raton, FL
| | - Deyou Zheng
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY,Department of Neurology, Albert Einstein College of Medicine, Bronx, NY,Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY
| | - Ales Cvekl
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY,Department of Genetics, Albert Einstein College of Medicine, Bronx, NY
| |
Collapse
|
16
|
Dailey L. High throughput technologies for the functional discovery of mammalian enhancers: new approaches for understanding transcriptional regulatory network dynamics. Genomics 2015; 106:151-158. [PMID: 26072436 DOI: 10.1016/j.ygeno.2015.06.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 04/18/2015] [Accepted: 06/08/2015] [Indexed: 01/08/2023]
Abstract
Completion of the human and mouse genomes has inspired new initiatives to obtain a global understanding of the functional regulatory networks governing gene expression. Enhancers are primary regulatory DNA elements determining precise spatio- and temporal gene expression patterns, but the observation that they can function at any distance from the gene(s) they regulate has made their genome-wide characterization challenging. Since traditional, single reporter approaches would be unable to accomplish this enormous task, high throughput technologies for mapping chromatin features associated with enhancers have emerged as an effective surrogate for enhancer discovery. However, the last few years have witnessed the development of several new innovative approaches that can effectively screen for and discover enhancers based on their functional activation of transcription using massively parallel reporter systems. In addition to their application for genome annotation, these new high throughput functional approaches open new and exciting avenues for modeling gene regulatory networks.
Collapse
Affiliation(s)
- Lisa Dailey
- NYU School of Medicine, Department of Microbiology, Kimmel Center for Stem Cell Biology, 550 First Avenue, MSB 252, New York, NY 10016, United States.
| |
Collapse
|