101
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Serebreni L, Stark A. Insights into gene regulation: From regulatory genomic elements to DNA-protein and protein-protein interactions. Curr Opin Cell Biol 2020; 70:58-66. [PMID: 33385708 DOI: 10.1016/j.ceb.2020.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/19/2020] [Accepted: 11/29/2020] [Indexed: 01/19/2023]
Abstract
Transcription is orchestrated by non-coding regulatory elements embedded in chromatin, which exist within the larger context of chromosome topology. Here, we review recent insights into the functions of non-coding regulatory elements and their protein interactors during transcription control. A picture emerges in which the topological environment constraints enhancer-promoter interactions and specific enhancer-bound proteins with distinct promoter-compatibilities refine target promoter choice. Such compatibilities are encoded within the sequences of enhancers and promoters and realized by diverse transcription factors and cofactors with distinct biochemical activities. An emerging property of transcription factors and cofactors is the formation of nuclear microenvironments or membraneless compartments that can have properties of phase-separated liquids. These environments are able to selectively enrich certain proteins and small molecules over others. Further investigation into the interaction of transcriptional regulators with themselves and regulatory DNA elements will help reveal the complexities of gene regulation within the context of the nucleus.
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Affiliation(s)
- Leonid Serebreni
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria; Medical University of Vienna, Vienna BioCenter (VBC), Vienna, Austria.
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102
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Gao Z, Zhang J, Wu Y. TFAP2A inhibits microRNA-126 expression at the transcriptional level and aggravates ischemic neuronal injury. Biochem Cell Biol 2020; 99:403-413. [PMID: 33264079 DOI: 10.1139/bcb-2020-0361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Neuronal injury induced by cerebral ischemia poses a serious health risk globally, and there is no effective clinical therapy. This study was performed to investigate the role of transcription factor AP-2 alpha (TFAP2A) in cerebral ischemia, and the underlying mechanisms, using an in-vitro model (PC-12 cells) of oxygen-glucose deprivation (OGD), and an in-vivo model (rat) of transient global cerebral ischemia (tGCI). The results for CCK-8 and Hoechst staining showed that silencing of TFAP2A enhanced the viability and decreased the rate of apoptosis of PC12 cells subjected to OGD. ChIP assays were performed to evaluate the binding of TFAP2A to the promoter region of microRNA (miR)-126, and we found that TFAP2A inhibits the expression of miR-126. Further mechanistic investigation revealed that miR-126 targets polo like kinase 2 (PLK2), and that overexpression of PLK2 activates the IκBα-NF-κB signaling pathway and suppresses the growth of PC12 cells subjected to OGD. For our in-vivo assay, we used TTC staining to analyze the infarction area in the brain tissues of rats, and Nissl staining to evaluate the number of surviving brain neurons. The pathological conditions associated with neuronal injury in rat brain tissues were assessed by staining the tissues with hematoxylin-eosin. Our results indicate that TFAP2A downregulates miR-126, and thereby upregulates PLK2 and activates the IκBα-NF-κB pathway, which increased neuronal injury following cerebral ischemia.
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Affiliation(s)
- Zhiqiang Gao
- Department of Neurology, Linyi Central Hospital, Linyi, Shandong 276400, P.R. China.,Department of Neurology, Linyi Central Hospital, Linyi, Shandong 276400, P.R. China
| | - Jiang Zhang
- Department of Neurology, Linyi Central Hospital, Linyi, Shandong 276400, P.R. China.,Department of Neurology, Linyi Central Hospital, Linyi, Shandong 276400, P.R. China
| | - Yunxia Wu
- Department of Neurology, Linyi Central Hospital, Linyi, Shandong 276400, P.R. China.,Department of Neurology, Linyi Central Hospital, Linyi, Shandong 276400, P.R. China
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103
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Kim J. Cellular reprogramming to model and study epigenetic alterations in cancer. Stem Cell Res 2020; 49:102062. [PMID: 33202305 PMCID: PMC7768185 DOI: 10.1016/j.scr.2020.102062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 10/17/2020] [Accepted: 10/20/2020] [Indexed: 12/14/2022] Open
Abstract
Cellular reprogramming to model human cancer. Cellular reprogramming to rewire epigenetic alterations in human cancer. Selective reactivation of malignancy in the cell lineage cancer is originated. Cellular reprogramming to recapitulate human cancer progression.
Although genetic mutations are required for cancer development, reversible non-genetic alterations also play a pivotal role in cancer progression. Failure of well-orchestrated gene regulation by chromatin states and master transcription factors can be one such non-genetic etiology for cancer development. Master transcription factor-mediated cellular reprogramming of human cancer cells allows us to model cancer progression. Here I cover the history and recent advances in reprogramming cancer cells, followed by lessons from cellular reprogramming of normal cells that may apply to cancer. Lastly, I share my perspective on cellular reprogramming for studying epigenetic alterations that have occurred in tumorigenesis, discuss the current limitations, and propose ways to overcome the obstacles in the reprogramming of cancer.
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Affiliation(s)
- Jungsun Kim
- Department of Molecular and Medical Genetics, Cancer Early Detection Advanced Research Center, Knight Cancer Institute (Cancer Biology Research Program), Oregon Health & Science University School of Medicine, KCRB 5001.51, 2720 SW Moody Ave., Portland, OR 97201, United States.
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104
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Charest J, Daniele T, Wang J, Bykov A, Mandlbauer A, Asparuhova M, Röhsner J, Gutiérrez-Pérez P, Cochella L. Combinatorial Action of Temporally Segregated Transcription Factors. Dev Cell 2020; 55:483-499.e7. [PMID: 33002421 PMCID: PMC7704111 DOI: 10.1016/j.devcel.2020.09.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/30/2020] [Accepted: 09/01/2020] [Indexed: 01/05/2023]
Abstract
Combinatorial action of transcription factors (TFs) with partially overlapping expression is a widespread strategy to generate novel gene-expression patterns and, thus, cellular diversity. Known mechanisms underlying combinatorial activity require co-expression of TFs within the same cell. Here, we describe the mechanism by which two TFs that are never co-expressed generate a new, intersectional expression pattern in C. elegans embryos: lineage-specific priming of a gene by a transiently expressed TF generates a unique intersection with a second TF acting on the same gene four cell divisions later; the second TF is expressed in multiple cells but only activates transcription in those where priming occurred. Early induction of active transcription is necessary and sufficient to establish a competent state, maintained by broadly expressed regulators in the absence of the initial trigger. We uncover additional cells diversified through this mechanism. Our findings define a mechanism for combinatorial TF activity with important implications for generation of cell-type diversity. Lineage-specific priming enables asymmetric gene expression in L/R neuron pairs Transient, lineage-specific TFs prime a locus for later activation by a bilateral TF An early active transcriptional state is necessary and sufficient for priming Maintenance of asymmetric primed state occurs in a symmetric regulatory environment
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Affiliation(s)
- Julien Charest
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Thomas Daniele
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Jingkui Wang
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Aleksandr Bykov
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Ariane Mandlbauer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Mila Asparuhova
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Josef Röhsner
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Paula Gutiérrez-Pérez
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Luisa Cochella
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria.
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105
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Bai Y, Zhou BR. Structures of Native-like Nucleosomes: One Step Closer toward Understanding the Structure and Function of Chromatin. J Mol Biol 2020; 433:166648. [PMID: 32920051 DOI: 10.1016/j.jmb.2020.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 02/08/2023]
Abstract
Genomic DNA in eukaryotes is organized into chromatin through association with core histone proteins to form nucleosomes. To understand the structure and function of chromatin, we must determine the structures of nucleosomes containing native DNA sequences. However, to date, our knowledge of nucleosome structures is mainly based on the crystallographic studies of the nucleosomes containing non-native DNA sequences. Here, we discuss the technical issues related to the determination of the nucleosome structures and review the few structural studies on native-like nucleosomes. We show how an antibody fragment-aided single-particle cryo-EM can be a useful method to determine the structures of nucleosomes containing genomic DNA. Finally, we provide a perspective for future structural studies of some native-like nucleosomes that play critical roles in chromatin functions.
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Affiliation(s)
- Yawen Bai
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Bing-Rui Zhou
- Laboratory of Biochemistry and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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106
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Abstract
Pioneer transcription factors have the intrinsic biochemical ability to scan partial DNA sequence motifs that are exposed on the surface of a nucleosome and thus access silent genes that are inaccessible to other transcription factors. Pioneer factors subsequently enable other transcription factors, nucleosome remodeling complexes, and histone modifiers to engage chromatin, thereby initiating the formation of an activating or repressive regulatory sequence. Thus, pioneer factors endow the competence for fate changes in embryonic development, are essential for cellular reprogramming, and rewire gene networks in cancer cells. Recent studies with reconstituted nucleosomes in vitro and chromatin binding in vivo reveal that pioneer factors can directly perturb nucleosome structure and chromatin accessibility in different ways. This review focuses on our current understanding of the mechanisms by which pioneer factors initiate gene network changes and will ultimately contribute to our ability to control cell fates at will.
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Affiliation(s)
- Kenneth S Zaret
- Institute for Regenerative Medicine, Epigenetics Institute, Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-5157, USA;
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107
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Feng Y, Huang J, Qu C, Huang M, Chen Z, Tang D, Xu Z, Wang B, Chen Z. Future perspective: high-throughput construction of new ultrasensitive cytokine and virion liquid chips for high-throughput screening (HTS) of anti-inflammatory drugs or clinical diagnosis and treatment of inflammatory diseases. Anal Bioanal Chem 2020; 412:7685-7699. [PMID: 32870351 PMCID: PMC7459963 DOI: 10.1007/s00216-020-02894-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 07/31/2020] [Accepted: 08/18/2020] [Indexed: 01/01/2023]
Abstract
Pathogen-host cell interactions play an important role in many human infectious and inflammatory diseases. Several pathogens, including Escherichia coli (E. coli), Mycobacterium tuberculosis (M. tb), and even the recent 2019 novel coronavirus (2019-nCoV), can cause serious breathing and brain disorders, tissue injury and inflammation, leading to high rates of mortality and resulting in great loss to human physical and mental health as well as the global economy. These infectious diseases exploit the microbial and host factors to induce serious inflammatory and immunological symptoms. Thus the development of anti-inflammatory drugs targeting bacterial/viral infection is an urgent need. In previous studies, YojI-IFNAR2, YojI-IL10RA, YojI-NRP1,YojI-SIGLEC7, and YojI-MC4R membrane-protein interactions were found to mediate E. coli invasion of the blood-brain barrier (BBB), which activated the downstream anti-inflammatory proteins NACHT, LRR and PYD domains-containing protein 2(NLRP2), using a proteomic chip conjugated with cell immunofluorescence labeling. However, the studies of pathogen (bacteria/virus)-host cell interactions mediated by membrane protein interactions did not extend their principles to broad biomedical applications such as 2019-nCoV infectious disease therapy. The first part of this feature article presents in-depth analysis of the cross-talk of cellular anti-inflammatory transduction signaling among interferon membrane protein receptor II (IFNAR2), interleukin-10 receptor subunit alpha (IL-10RA), NLRP2 and [Ca2+]-dependent phospholipase A2 (PLA2G5), based on experimental results and important published studies, which lays a theoretical foundation for the high-throughput construction of the cytokine and virion solution chip. The paper then moves on to the construction of the novel GPCR recombinant herpes virion chip and virion nano-oscillators for profiling membrane protein functions, which drove the idea of constructing the new recombinant virion and cytokine liquid chips for HTS of leading drugs. Due to the different structural properties of GPCR, IFNAR2, ACE2 and Spike of 2019-nCoV, their ligands will either bind the extracellular domain of IFNAR2/ACE2/Spike or the specific loops of the GPCR on the envelope of the recombinant herpes virions to induce dynamic charge distribution changes that lead to the variable electron transition for detection. Taken together, the combined overview of two of the most innovative and exciting developments in the immunoinflammatory field provides new insight into high-throughput construction of ultrasensitive cytokine and virion liquid chips for HTS of anti-inflammatory drugs or clinical diagnosis and treatment of inflammatory diseases including infectious diseases, acute or chronic inflammation (acute gouty arthritis or rheumatoid arthritis), cardiovascular disease, atheromatosis, diabetes, obesity, tissue injury and tumors. It has significant value in the prevention and treatment of these serious and painful diseases. Graphical abstract.
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Affiliation(s)
- Yingzhu Feng
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China. .,Key Laboratory of Bio-theological Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400045, China.
| | - Jiuhong Huang
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China
| | - Chuanhua Qu
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China
| | - Mengjun Huang
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China
| | - Zhencong Chen
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China
| | - Dianyong Tang
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China
| | - Zhigang Xu
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China
| | - Bochu Wang
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China. .,Key Laboratory of Bio-theological Science and Technology of Ministry of Education, College of Bioengineering, Chongqing University, Chongqing, 400045, China.
| | - Zhongzhu Chen
- College of Pharmacy & International Academy of Targeted Therapeutics and Innovation (IATTI), Chongqing University of Art and Sciences, Chongqing, 402160, China.
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108
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Tanaka H, Takizawa Y, Takaku M, Kato D, Kumagawa Y, Grimm SA, Wade PA, Kurumizaka H. Interaction of the pioneer transcription factor GATA3 with nucleosomes. Nat Commun 2020; 11:4136. [PMID: 32811816 PMCID: PMC7434886 DOI: 10.1038/s41467-020-17959-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 07/22/2020] [Indexed: 01/23/2023] Open
Abstract
During cellular reprogramming, the pioneer transcription factor GATA3 binds chromatin, and in a context-dependent manner directs local chromatin remodeling and enhancer formation. Here, we use high-resolution nucleosome mapping in human cells to explore the impact of the position of GATA motifs on the surface of nucleosomes on productive enhancer formation, finding productivity correlates with binding sites located near the nucleosomal dyad axis. Biochemical experiments with model nucleosomes demonstrate sufficiently stable transcription factor-nucleosome interaction to empower cryo-electron microscopy structure determination of the complex at 3.15 Å resolution. The GATA3 zinc fingers efficiently bind their target 5′-GAT-3′ sequences in the nucleosome when they are located in solvent accessible, consecutive major grooves without significant changes in nucleosome structure. Analysis of genomic loci bound by GATA3 during reprogramming suggests a correlation of recognition motif sequence and spacing that may distinguish productivity of new enhancer formation. GATA 3 functions as a pioneer factor during cellular reprogramming. Here the authors delineate nucleosome positioning relative to GATA3 binding motifs and describe the structure of a GATA3–nucleosome complex; providing insight into how a pioneer factor interacts with nucleosomes and catalyze their local remodelling to produce an accessible enhancer.
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Affiliation(s)
- Hiroki Tanaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.,Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan
| | - Yoshimasa Takizawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Motoki Takaku
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, 27709, USA.,Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - Daiki Kato
- Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.,Laboratory for Drug Discovery, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 MifukuIzunokuni-shi, Shizuoka, 410-2321, Japan
| | - Yusuke Kumagawa
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan
| | - Sara A Grimm
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, 27709, USA
| | - Paul A Wade
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, 27709, USA.
| | - Hitoshi Kurumizaka
- Laboratory of Chromatin Structure and Function, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan. .,Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo, 162-8480, Japan.
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109
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Abstract
While recent experiments revealed that some pioneer transcription factors (TFs) can bind to their target DNA sequences inside a nucleosome, the binding dynamics of their target recognitions are poorly understood. Here we used the latest coarse-grained models and molecular dynamics simulations to study the nucleosome-binding procedure of the two pioneer TFs, Sox2 and Oct4. In the simulations for a strongly positioning nucleosome, Sox2 selected its target DNA sequence only when the target was exposed. Otherwise, Sox2 entropically bound to the dyad region nonspecifically. In contrast, Oct4 plastically bound on the nucleosome mainly in two ways. First, the two POU domains of Oct4 separately bound to the two parallel gyres of the nucleosomal DNA, supporting the previous experimental results of the partial motif recognition. Second, the POUS domain of Oct4 favored binding on the acidic patch of histones. Then, simulating the TFs binding to a genomic nucleosome, the LIN28B nucleosome, we found that the recognition of a pseudo motif by Sox2 induced the local DNA bending and shifted the population of the rotational position of the nucleosomal DNA. The redistributed DNA phase, in turn, changed the accessibility of a distant TF binding site, which consequently affected the binding probability of a second Sox2 or Oct4. These results revealed a nucleosomal DNA-mediated allosteric mechanism, through which one TF binding event can change the global conformation, and effectively regulate the binding of another TF at distant sites. Our simulations provide insights into the binding mechanism of single and multiple TFs on the nucleosome.
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110
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Sanchez JC, Zhang L, Evoli S, Schnicker NJ, Nunez-Hernandez M, Yu L, Wereszczynski J, Pufall MA, Musselman CA. The molecular basis of selective DNA binding by the BRG1 AT-hook and bromodomain. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2020; 1863:194566. [PMID: 32376391 PMCID: PMC7350285 DOI: 10.1016/j.bbagrm.2020.194566] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/21/2020] [Accepted: 04/21/2020] [Indexed: 12/18/2022]
Abstract
The ATP-dependent BAF chromatin remodeling complex plays a critical role in gene regulation by modulating chromatin architecture, and is frequently mutated in cancer. Indeed, subunits of the BAF complex are found to be mutated in >20% of human tumors. The mechanism by which BAF properly navigates chromatin is not fully understood, but is thought to involve a multivalent network of histone and DNA contacts. We previously identified a composite domain in the BRG1 ATPase subunit that is capable of associating with both histones and DNA in a multivalent manner. Mapping the DNA binding pocket revealed that it contains several cancer mutations. Here, we utilize SELEX-seq to investigate the DNA specificity of this composite domain and NMR spectroscopy and molecular modelling to determine the structural basis of DNA binding. Finally, we demonstrate that cancer mutations in this domain alter the mode of DNA association.
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Affiliation(s)
- Julio C Sanchez
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Liyang Zhang
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Integrated DNA Technologies IDT, Coralville, IA 52241, United States
| | - Stefania Evoli
- Department of Physics and The Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, IL, United States
| | - Nicholas J Schnicker
- Protein & Crystallography Facility, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Maria Nunez-Hernandez
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States
| | - Liping Yu
- Department of Biochemistry, Carver College of Medicine NMR Core Facility, University of Iowa, Iowa City, IA 52242, United States; The Iowa City Veterans Affairs Medical Center, Iowa City, IA 52242, United States
| | - Jeff Wereszczynski
- Department of Physics and The Center for Molecular Study of Condensed Soft Matter, Illinois Institute of Technology, Chicago, IL, United States.
| | - Miles A Pufall
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States.
| | - Catherine A Musselman
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, United States; Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States.
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111
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Lerner J, Gomez-Garcia PA, McCarthy RL, Liu Z, Lakadamyali M, Zaret KS. Two-Parameter Mobility Assessments Discriminate Diverse Regulatory Factor Behaviors in Chromatin. Mol Cell 2020; 79:677-688.e6. [PMID: 32574554 DOI: 10.1016/j.molcel.2020.05.036] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 04/06/2020] [Accepted: 05/27/2020] [Indexed: 12/20/2022]
Abstract
Enzymatic probes of chromatin structure reveal accessible versus inaccessible chromatin states, while super-resolution microscopy reveals a continuum of chromatin compaction states. Characterizing histone H2B movements by single-molecule tracking (SMT), we resolved chromatin domains ranging from low to high mobility and displaying different subnuclear localizations patterns. Heterochromatin constituents correlated with the lowest mobility chromatin, whereas transcription factors varied widely with regard to their respective mobility with low- or high-mobility chromatin. Pioneer transcription factors, which bind nucleosomes, can access the low-mobility chromatin domains, whereas weak or non-nucleosome binding factors are excluded from the domains and enriched in higher mobility domains. Nonspecific DNA and nucleosome binding accounted for most of the low mobility of strong nucleosome interactor FOXA1. Our analysis shows how the parameters of the mobility of chromatin-bound factors, but not their diffusion behaviors or SMT-residence times within chromatin, distinguish functional characteristics of different chromatin-interacting proteins.
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Affiliation(s)
- Jonathan Lerner
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Pablo Aurelio Gomez-Garcia
- Center for Genomic Regulation, Barcelona Biomedical Research Park, 08003 Barcelona, Spain; ICFO-Institute of Photonics Sciences, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Ryan L McCarthy
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA
| | - Zhe Liu
- HHMI Janelia Research Campus, Ashburn, VA 20147, USA
| | - Melike Lakadamyali
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA; University of Pennsylvania, Department of Physiology, Philadelphia, PA 19104-6058, USA
| | - Kenneth S Zaret
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-6058, USA.
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112
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Abstract
Cell-type- and condition-specific profiles of gene expression require coordination between protein-coding gene promoters and cis-regulatory sequences called enhancers. Enhancers can stimulate gene activity at great genomic distances from their targets, raising questions about how enhancers communicate with specific gene promoters and what molecular mechanisms underlie enhancer function. Characterization of enhancer loci has identified the molecular features of active enhancers that accompany the binding of transcription factors and local opening of chromatin. These characteristics include coactivator recruitment, histone modifications, and noncoding RNA transcription. However, it remains unclear which of these features functionally contribute to enhancer activity. Here, we discuss what is known about how enhancers regulate their target genes and how enhancers and promoters communicate. Further, we describe recent data demonstrating many similarities between enhancers and the gene promoters they control, and we highlight unanswered questions in the field, such as the potential roles of transcription at enhancers.
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Affiliation(s)
- Andrew Field
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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113
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Michael AK, Grand RS, Isbel L, Cavadini S, Kozicka Z, Kempf G, Bunker RD, Schenk AD, Graff-Meyer A, Pathare GR, Weiss J, Matsumoto S, Burger L, Schübeler D, Thomä NH. Mechanisms of OCT4-SOX2 motif readout on nucleosomes. Science 2020; 368:1460-1465. [PMID: 32327602 DOI: 10.1126/science.abb0074] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
Transcription factors (TFs) regulate gene expression through chromatin where nucleosomes restrict DNA access. To study how TFs bind nucleosome-occupied motifs, we focused on the reprogramming factors OCT4 and SOX2 in mouse embryonic stem cells. We determined TF engagement throughout a nucleosome at base-pair resolution in vitro, enabling structure determination by cryo-electron microscopy at two preferred positions. Depending on motif location, OCT4 and SOX2 differentially distort nucleosomal DNA. At one position, OCT4-SOX2 removes DNA from histone H2A and histone H3; however, at an inverted motif, the TFs only induce local DNA distortions. OCT4 uses one of its two DNA-binding domains to engage DNA in both structures, reading out a partial motif. These findings explain site-specific nucleosome engagement by the pluripotency factors OCT4 and SOX2, and they reveal how TFs distort nucleosomes to access chromatinized motifs.
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Affiliation(s)
- Alicia K Michael
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Ralph S Grand
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Luke Isbel
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Simone Cavadini
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Zuzanna Kozicka
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.,Faculty of Science, University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Georg Kempf
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Richard D Bunker
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Andreas D Schenk
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Alexandra Graff-Meyer
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Ganesh R Pathare
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Joscha Weiss
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Syota Matsumoto
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Lukas Burger
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.,Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Dirk Schübeler
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland. .,Faculty of Science, University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Nicolas H Thomä
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland.
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114
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Retureau R, Foloppe N, Elbahnsi A, Oguey C, Hartmann B. A dynamic view of DNA structure within the nucleosome: Biological implications. J Struct Biol 2020; 211:107511. [PMID: 32311461 DOI: 10.1016/j.jsb.2020.107511] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 01/21/2023]
Abstract
Most of eukaryotic cellular DNA is packed in nucleosome core particles (NCPs), in which the DNA (DNANCP) is wrapped around histones. The influence of this organization on the intrinsic local dynamics of DNA is largely unknown, in particular because capturing such information from experiments remains notoriously challenging. Given the importance of dynamical properties in DNA functions, we addressed this issue using CHARMM36 MD simulations of a nucleosome containing the NCP positioning 601 sequence and four related free dodecamers. Comparison between DNANCP and free DNA reveals a limited impact of the dense DNA-histone interface on correlated motions of dinucleotide constituents and on fluctuations of inter base pair parameters. A characteristic feature intimately associated with the DNANCP super-helical path is a set of structural periodicities that includes a marked alternation of regions enriched in backbone BI and BII conformers. This observation led to uncover a convincing correspondence between the sequence effect on BI/BII propensities in both DNANCP and free DNA, strengthening the idea that the histone preference for particular DNA sequences relies on those intrinsic structural properties. These results offer for the first time a detailed view of the DNA dynamical behavior within NCP. They show in particular that the DNANCP dynamics is substantial enough to preserve the ability to structurally adjust to external proteins, for instance remodelers. Also, fresh structural arguments highlight the relevance of relationships between DNA sequence and structural properties for NCP formation. Overall, our work offers a more rational framework to approach the functional, biological roles of NCP.
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Affiliation(s)
- Romain Retureau
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, Laboratoire de biologie et pharmacologie appliquée, 61 avenue du Président Wilson, 94235 Cachan cedex, France
| | | | - Ahmad Elbahnsi
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, Laboratoire de biologie et pharmacologie appliquée, 61 avenue du Président Wilson, 94235 Cachan cedex, France; LPTM, UMR8089, CNRS, CY Cergy Paris Université, 2 avenue Adolphe Chauvin, 95302 Cergy-Pontoise, France
| | - Christophe Oguey
- LPTM, UMR8089, CNRS, CY Cergy Paris Université, 2 avenue Adolphe Chauvin, 95302 Cergy-Pontoise, France
| | - Brigitte Hartmann
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, Laboratoire de biologie et pharmacologie appliquée, 61 avenue du Président Wilson, 94235 Cachan cedex, France.
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115
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Yu X, Buck MJ. Pioneer factors and their in vitro identification methods. Mol Genet Genomics 2020; 295:825-835. [PMID: 32296927 DOI: 10.1007/s00438-020-01675-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 04/02/2020] [Indexed: 11/27/2022]
Abstract
Pioneer transcription factors are a special group of transcription factors that can interact with nucleosomal DNA and initiate regulatory events. Their binding to regulatory regions is the first event in gene activation and can occur in silent or heterochromatin regions. Several research groups have endeavored to define pioneer factors and study their binding characteristics using various techniques. In this review, we describe the in vitro methods used to define and characterize pioneer factors, paying particular attention to differences in methodologies and how these differences can affect results.
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Affiliation(s)
- Xinyang Yu
- Zhuhai Precision Medical Center, Zhuhai People's Hospital (Zhuhai Hospital Affiliated With Jinan University), Zhuhai, 519000, Guangdong, P.R. China.
| | - Michael J Buck
- Department of Biochemistry, New York State Center of Excellence in Bioinformatics and Life Sciences, State University of New York at Buffalo, Buffalo, NY, 14203, USA.
- Department of Biomedical Informatics, State University of New York at Buffalo, Buffalo, NY, 14203, USA.
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116
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Suter DM. Transcription Factors and DNA Play Hide and Seek. Trends Cell Biol 2020; 30:491-500. [PMID: 32413318 DOI: 10.1016/j.tcb.2020.03.003] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/12/2020] [Accepted: 03/16/2020] [Indexed: 01/12/2023]
Abstract
Transcription factors (TFs) bind to specific DNA motifs to regulate the expression of target genes. To reach their binding sites, TFs diffuse in 3D and perform local motions such as 1D sliding, hopping, or intersegmental transfer. TF-DNA interactions depend on multiple parameters, such as the chromatin environment, TF partitioning into distinct subcellular regions, and cooperativity with other DNA-binding proteins. In this review, how current understanding of the search process has initially been shaped by prokaryotic studies is discussed, as well as what is known about the parameters regulating TF search efficiency in the context of the complex eukaryotic chromatin landscape.
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Affiliation(s)
- David M Suter
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
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117
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Schiessel H, Blossey R. Pioneer transcription factors in chromatin remodeling: The kinetic proofreading view. Phys Rev E 2020; 101:040401. [PMID: 32422793 DOI: 10.1103/physreve.101.040401] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 03/23/2020] [Indexed: 06/11/2023]
Abstract
Pioneer transcription factors are a recently defined class of transcription factors which can bind directly to nucleosomal DNA; they play a key role in gene activation in certain pathways. Here we quantify their role in the initiation of nucleosome displacement within the kinetic proofreading scenario of chromatin remodeling. The model allows one to perform remodeling efficiency comparisons for scenarios involving different types of transcription factors and remodelers as a function of their binding and unbinding rates and concentrations. Our results demonstrate a way to fine-tune the specificity of processes that modify the chromatin structure in transcriptional initiation.
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Affiliation(s)
- Helmut Schiessel
- Institute Lorentz for Theoretical Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, the Netherlands
| | - Ralf Blossey
- University of Lille, Unité de Glycobiologie Structurale et Fonctionnelle, CNRS UMR8576, 59000 Lille, France
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118
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Gene network transitions in embryos depend upon interactions between a pioneer transcription factor and core histones. Nat Genet 2020; 52:418-427. [PMID: 32203463 PMCID: PMC7901023 DOI: 10.1038/s41588-020-0591-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 02/14/2020] [Indexed: 12/17/2022]
Abstract
Gene network transitions in embryos and other fate-changing contexts involve combinations of transcription factors. A subset of fate-changing transcription factors act as pioneers; they scan and target nucleosomal DNA and initiate cooperative events that can open the local chromatin. But a gap has remained in understanding how molecular interactions with the nucleosome contribute to the chromatin-opening phenomenon. Here we identified a short alpha-helical region, conserved among FOXA pioneer factors, that interacts with core histones and contributes to chromatin opening in vitro. The same domain is involved in chromatin opening in early mouse embryos for normal development. Thus, local opening of chromatin by interactions between pioneer factors and core histones promotes genetic programming.
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119
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Bozek M, Gompel N. Developmental Transcriptional Enhancers: A Subtle Interplay between Accessibility and Activity: Considering Quantitative Accessibility Changes between Different Regulatory States of an Enhancer Deconvolutes the Complex Relationship between Accessibility and Activity. Bioessays 2020; 42:e1900188. [PMID: 32142172 DOI: 10.1002/bies.201900188] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/16/2020] [Indexed: 12/21/2022]
Abstract
Measurements of open chromatin in specific cell types are widely used to infer the spatiotemporal activity of transcriptional enhancers. How reliable are these predictions? In this review, it is argued that the relationship between the accessibility and activity of an enhancer is insufficiently described by simply considering open versus closed chromatin, or active versus inactive enhancers. Instead, recent studies focusing on the quantitative nature of accessibility signal reveal subtle differences between active enhancers and their different inactive counterparts: the closed silenced state and the accessible primed and repressed states. While the open structure as such is not a specific indicator of enhancer activity, active enhancers display a higher degree of accessibility than the primed and repressed states. Molecular mechanisms that may account for these quantitative differences are discussed. A model that relates molecular events at an enhancer to changes in its activity and accessibility in a developing tissue is also proposed.
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Affiliation(s)
- Marta Bozek
- Department Biochemie, Ludwig-Maximilians Universität München, Genzentrum, 81377, München, Germany
| | - Nicolas Gompel
- Fakultät für Biologie, Ludwig-Maximilians Universität München, Biozentrum, 82152, Planegg-Martinsried, Germany
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120
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Srinivasan R, Nady N, Arora N, Hsieh LJ, Swigut T, Narlikar GJ, Wossidlo M, Wysocka J. Zscan4 binds nucleosomal microsatellite DNA and protects mouse two-cell embryos from DNA damage. SCIENCE ADVANCES 2020; 6:eaaz9115. [PMID: 32219172 PMCID: PMC7083622 DOI: 10.1126/sciadv.aaz9115] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/02/2020] [Indexed: 05/07/2023]
Abstract
Zinc finger protein Zscan4 is selectively expressed in mouse two-cell (2C) embryos undergoing zygotic genome activation (ZGA) and in a rare subpopulation of embryonic stem cells with 2C-like features. Here, we show that Zscan4 specifically recognizes a subset of (CA)n microsatellites, repeat sequences prone to genomic instability. Zscan4-associated microsatellite regions are characterized by low nuclease sensitivity and high histone occupancy. In vitro, Zscan4 binds nucleosomes and protects them from disassembly upon torsional strain. Furthermore, Zscan4 depletion leads to elevated DNA damage in 2C mouse embryos in a transcription-dependent manner. Together, our results identify Zscan4 as a DNA sequence-dependent microsatellite binding factor and suggest a developmentally regulated mechanism, which protects fragile genomic regions from DNA damage at a time of embryogenesis associated with high transcriptional burden and genomic stress.
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Affiliation(s)
- Rajini Srinivasan
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nataliya Nady
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Neha Arora
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laura J. Hsieh
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Tomek Swigut
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Geeta J. Narlikar
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Mark Wossidlo
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Cell and Developmental Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Joanna Wysocka
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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121
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Karagianni P, Moulos P, Schmidt D, Odom DT, Talianidis I. Bookmarking by Non-pioneer Transcription Factors during Liver Development Establishes Competence for Future Gene Activation. Cell Rep 2020; 30:1319-1328.e6. [PMID: 32023452 PMCID: PMC7003066 DOI: 10.1016/j.celrep.2020.01.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 12/02/2019] [Accepted: 12/31/2019] [Indexed: 01/01/2023] Open
Abstract
Transcription factor binding to enhancer and promoter regions critical for homeostatic adult gene activation is established during development. To understand how cell-specific gene expression patterns are generated, we study the developmental timing of association of two prominent hepatic transcription factors with gene regulatory regions. Most individual binding events display extraordinarily high temporal variations during liver development. Early and persistent binding is necessary, but not sufficient, for gene activation. Stable gene expression patterns are the result of combinatorial activity of multiple transcription factors, which mark regulatory regions long before activation and promote progressive broadening of active chromatin domains. Both temporally stable and dynamic, short-lived binding events contribute to the developmental maturation of active promoter configurations. The results reveal a developmental bookmarking function of master regulators and illuminate remarkable parallels between the principles employed for gene activation during development, during evolution, and upon mitotic exit.
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Affiliation(s)
- Panagiota Karagianni
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 70013 Herakleion, Crete, Greece; Biomedical Sciences Research Center Alexander Fleming, 16672 Vari, Greece
| | - Panagiotis Moulos
- Biomedical Sciences Research Center Alexander Fleming, 16672 Vari, Greece
| | - Dominic Schmidt
- Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Duncan T Odom
- Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK
| | - Iannis Talianidis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 70013 Herakleion, Crete, Greece.
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122
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Gosselin D. Epigenomic and transcriptional determinants of microglial cell identity. Glia 2020; 68:1643-1654. [PMID: 31994799 DOI: 10.1002/glia.23787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/08/2020] [Accepted: 01/16/2020] [Indexed: 11/09/2022]
Abstract
Microglia perform multiple tasks that are essential to ensure proper cerebral functions, including synaptic remodeling, clearance of molecular debris, prevention of infections, and so forth. Furthermore, accumulating genetic and pathological evidence implicates microglial cell activity in the etiology of numerous neurodegenerative diseases and psychiatric disorders. Given this, efforts aimed at understanding the molecular mechanisms underlying microglial cell functions hold great potential for the development of novel therapies for various conditions affecting the central nervous system. In that regard, the application of paradigms in epigenomics to study transcription in microglia has provided significant insights into the molecular mechanisms that control the ontogeny and functions of these cells. With a focus on the roles of genomic regulatory elements and the epigenetic marks that control microglial gene expression, we review here recent key advancements in our comprehension of the epigenomic and transcriptional mechanisms that enable microglial cell development and activity.
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Affiliation(s)
- David Gosselin
- Department of Molecular Medicine, Faculty of Medicine, CHU de Québec Research Center, Université Laval, Quebec City, Quebec, Canada
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123
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Rothstein M, Simoes-Costa M. Heterodimerization of TFAP2 pioneer factors drives epigenomic remodeling during neural crest specification. Genome Res 2019; 30:35-48. [PMID: 31848212 PMCID: PMC6961570 DOI: 10.1101/gr.249680.119] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 12/12/2019] [Indexed: 12/28/2022]
Abstract
Cell fate commitment involves the progressive restriction of developmental potential. Recent studies have shown that this process requires not only shifts in gene expression but also an extensive remodeling of the epigenomic landscape. To examine how chromatin states are reorganized during cellular specification in an in vivo system, we examined the function of pioneer factor TFAP2A at discrete stages of neural crest development. Our results show that TFAP2A activates distinct sets of genomic regions during induction of the neural plate border and specification of neural crest cells. Genomic occupancy analysis revealed that the repertoire of TFAP2A targets depends upon its dimerization with paralogous proteins TFAP2C and TFAP2B. During gastrula stages, TFAP2A/C heterodimers activate components of the neural plate border induction program. As neurulation begins, TFAP2A trades partners, and TFAP2A/B heterodimers reorganize the epigenomic landscape of progenitor cells to promote neural crest specification. We propose that this molecular switch acts to drive progressive cell commitment, remodeling the epigenomic landscape to define the presumptive neural crest. Our findings show how pioneer factors regulate distinct genomic targets in a stage-specific manner and highlight how paralogy can serve as an evolutionary strategy to diversify the function of the regulators that control embryonic development.
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Affiliation(s)
- Megan Rothstein
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
| | - Marcos Simoes-Costa
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA
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