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Lim F, Solvason JJ, Ryan GE, Le SH, Jindal GA, Steffen P, Jandu SK, Farley EK. Affinity-optimizing enhancer variants disrupt development. Nature 2024; 626:151-159. [PMID: 38233525 PMCID: PMC10830414 DOI: 10.1038/s41586-023-06922-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 11/30/2023] [Indexed: 01/19/2024]
Abstract
Enhancers control the location and timing of gene expression and contain the majority of variants associated with disease1-3. The ZRS is arguably the most well-studied vertebrate enhancer and mediates the expression of Shh in the developing limb4. Thirty-one human single-nucleotide variants (SNVs) within the ZRS are associated with polydactyly4-6. However, how this enhancer encodes tissue-specific activity, and the mechanisms by which SNVs alter the number of digits, are poorly understood. Here we show that the ETS sites within the ZRS are low affinity, and identify a functional ETS site, ETS-A, with extremely low affinity. Two human SNVs and a synthetic variant optimize the binding affinity of ETS-A subtly from 15% to around 25% relative to the strongest ETS binding sequence, and cause polydactyly with the same penetrance and severity. A greater increase in affinity results in phenotypes that are more penetrant and more severe. Affinity-optimizing SNVs in other ETS sites in the ZRS, as well as in ETS, interferon regulatory factor (IRF), HOX and activator protein 1 (AP-1) sites within a wide variety of enhancers, cause gain-of-function gene expression. The prevalence of binding sites with suboptimal affinity in enhancers creates a vulnerability in genomes whereby SNVs that optimize affinity, even slightly, can be pathogenic. Searching for affinity-optimizing SNVs in genomes could provide a mechanistic approach to identify causal variants that underlie enhanceropathies.
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Affiliation(s)
- Fabian Lim
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Biological Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Joe J Solvason
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Genevieve E Ryan
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Sophia H Le
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Granton A Jindal
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Paige Steffen
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Simran K Jandu
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Emma K Farley
- Department of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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2
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Johannesson K, Leder EH, André C, Dupont S, Eriksson SP, Harding K, Havenhand JN, Jahnke M, Jonsson PR, Kvarnemo C, Pavia H, Rafajlović M, Rödström EM, Thorndyke M, Blomberg A. Ten years of marine evolutionary biology-Challenges and achievements of a multidisciplinary research initiative. Evol Appl 2023; 16:530-541. [PMID: 36793681 PMCID: PMC9923476 DOI: 10.1111/eva.13389] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/08/2022] [Accepted: 04/21/2022] [Indexed: 11/26/2022] Open
Abstract
The Centre for Marine Evolutionary Biology (CeMEB) at the University of Gothenburg, Sweden, was established in 2008 through a 10-year research grant of 8.7 m€ to a team of senior researchers. Today, CeMEB members have contributed >500 scientific publications, 30 PhD theses and have organised 75 meetings and courses, including 18 three-day meetings and four conferences. What are the footprints of CeMEB, and how will the centre continue to play a national and international role as an important node of marine evolutionary research? In this perspective article, we first look back over the 10 years of CeMEB activities and briefly survey some of the many achievements of CeMEB. We furthermore compare the initial goals, as formulated in the grant application, with what has been achieved, and discuss challenges and milestones along the way. Finally, we bring forward some general lessons that can be learnt from a research funding of this type, and we also look ahead, discussing how CeMEB's achievements and lessons can be used as a springboard to the future of marine evolutionary biology.
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Affiliation(s)
- Kerstin Johannesson
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Erica H Leder
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden.,Natural History Museum University of Oslo Oslo Norway
| | - Carl André
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Sam Dupont
- Department of Biology and Environmental Science University of Gothenburg, Kristineberg Marine Research Station Fiskebäckskil Sweden.,International Atomic Energy Agency Principality of Monaco Monaco
| | - Susanne P Eriksson
- Department of Biology and Environmental Science University of Gothenburg, Kristineberg Marine Research Station Fiskebäckskil Sweden
| | - Karin Harding
- Department of Biology and Environmental Science University of Gothenburg Gothenburg Sweden
| | - Jonathan N Havenhand
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Marlene Jahnke
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Per R Jonsson
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Charlotta Kvarnemo
- Department of Biology and Environmental Science University of Gothenburg Gothenburg Sweden
| | - Henrik Pavia
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Marina Rafajlović
- Department of Marine Sciences University of Gothenburg Gothenburg Sweden
| | - Eva Marie Rödström
- Tjärnö Marine Laboratory, Department of Marine Sciences University of Gothenburg Strömstad Sweden
| | - Michael Thorndyke
- Department of Biology and Environmental Science University of Gothenburg, Kristineberg Marine Research Station Fiskebäckskil Sweden.,Department of Genomics Research in Ecology & Evolution in Nature (GREEN) Groningen Institute for Evolutionary Life Sciences (GELIFES) De Rijksuniversiteit Groningen Groningen The Netherlands
| | - Anders Blomberg
- Department of Chemistry and Molecular Biology University of Gothenburg Gothenburg Sweden
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3
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MacKenzie A, Hay EA, McEwan AR. Context-dependant enhancers as a reservoir of functional polymorphisms and epigenetic markers linked to alcohol use disorders and comorbidities. ADDICTION NEUROSCIENCE 2022; 2:None. [PMID: 35712020 PMCID: PMC9101288 DOI: 10.1016/j.addicn.2022.100014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/18/2022] [Accepted: 03/22/2022] [Indexed: 10/25/2022]
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4
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Kaplow IM, Schäffer DE, Wirthlin ME, Lawler AJ, Brown AR, Kleyman M, Pfenning AR. Inferring mammalian tissue-specific regulatory conservation by predicting tissue-specific differences in open chromatin. BMC Genomics 2022; 23:291. [PMID: 35410163 PMCID: PMC8996547 DOI: 10.1186/s12864-022-08450-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolutionary conservation is an invaluable tool for inferring functional significance in the genome, including regions that are crucial across many species and those that have undergone convergent evolution. Computational methods to test for sequence conservation are dominated by algorithms that examine the ability of one or more nucleotides to align across large evolutionary distances. While these nucleotide alignment-based approaches have proven powerful for protein-coding genes and some non-coding elements, they fail to capture conservation of many enhancers, distal regulatory elements that control spatial and temporal patterns of gene expression. The function of enhancers is governed by a complex, often tissue- and cell type-specific code that links combinations of transcription factor binding sites and other regulation-related sequence patterns to regulatory activity. Thus, function of orthologous enhancer regions can be conserved across large evolutionary distances, even when nucleotide turnover is high. RESULTS We present a new machine learning-based approach for evaluating enhancer conservation that leverages the combinatorial sequence code of enhancer activity rather than relying on the alignment of individual nucleotides. We first train a convolutional neural network model that can predict tissue-specific open chromatin, a proxy for enhancer activity, across mammals. Next, we apply that model to distinguish instances where the genome sequence would predict conserved function versus a loss of regulatory activity in that tissue. We present criteria for systematically evaluating model performance for this task and use them to demonstrate that our models accurately predict tissue-specific conservation and divergence in open chromatin between primate and rodent species, vastly out-performing leading nucleotide alignment-based approaches. We then apply our models to predict open chromatin at orthologs of brain and liver open chromatin regions across hundreds of mammals and find that brain enhancers associated with neuron activity have a stronger tendency than the general population to have predicted lineage-specific open chromatin. CONCLUSION The framework presented here provides a mechanism to annotate tissue-specific regulatory function across hundreds of genomes and to study enhancer evolution using predicted regulatory differences rather than nucleotide-level conservation measurements.
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Affiliation(s)
- Irene M Kaplow
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA. .,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA.
| | - Daniel E Schäffer
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Morgan E Wirthlin
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alyssa J Lawler
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA.,Department of Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Ashley R Brown
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Michael Kleyman
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Andreas R Pfenning
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA. .,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Biology, Carnegie Mellon University, Pittsburgh, PA, USA.
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5
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Martinez-Ara M, Comoglio F, van Arensbergen J, van Steensel B. Systematic analysis of intrinsic enhancer-promoter compatibility in the mouse genome. Mol Cell 2022; 82:2519-2531.e6. [PMID: 35594855 PMCID: PMC9278412 DOI: 10.1016/j.molcel.2022.04.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/17/2022] [Accepted: 04/05/2022] [Indexed: 12/12/2022]
Affiliation(s)
- Miguel Martinez-Ara
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Federico Comoglio
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Joris van Arensbergen
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands
| | - Bas van Steensel
- Division of Gene Regulation and Oncode Institute, Netherlands Cancer Institute, 1066 CX Amsterdam, the Netherlands.
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6
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Secchia S, Forneris M, Heinen T, Stegle O, Furlong EEM. Simultaneous cellular and molecular phenotyping of embryonic mutants using single-cell regulatory trajectories. Dev Cell 2022; 57:496-511.e8. [PMID: 35176234 PMCID: PMC8893321 DOI: 10.1016/j.devcel.2022.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/04/2021] [Accepted: 01/26/2022] [Indexed: 11/09/2022]
Abstract
Developmental progression and cellular diversity are largely driven by transcription factors (TFs); yet, characterizing their loss-of-function phenotypes remains challenging and often disconnected from their underlying molecular mechanisms. Here, we combine single-cell regulatory genomics with loss-of-function mutants to jointly assess both cellular and molecular phenotypes. Performing sci-ATAC-seq at eight overlapping time points during Drosophila mesoderm development could reconstruct the developmental trajectories of all major muscle types and reveal the TFs and enhancers involved. To systematically assess mutant phenotypes, we developed a single-nucleus genotyping strategy to process embryo pools of mixed genotypes. Applying this to four TF mutants could identify and quantify their characterized phenotypes de novo and discover new ones, while simultaneously revealing their regulatory input and mode of action. Our approach is a general framework to dissect the functional input of TFs in a systematic, unbiased manner, identifying both cellular and molecular phenotypes at a scale and resolution that has not been feasible before. scATAC time course constructs regulatory trajectories of Drosophila muscle lineages Combining a wild-type trajectory with mutants identifies and quantifies phenotypes de novo Digital nuclear genotyping enables the processing of pooled embryos of mixed genotypes This framework simultaneously uncovers cellular and molecular phenotypes in embryos
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Affiliation(s)
- Stefano Secchia
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany; Collaboration for Joint PhD Degree between EMBL and Heidelberg University, Faculty of Biosciences, Baden-Württemberg, Germany
| | - Mattia Forneris
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany
| | - Tobias Heinen
- Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Baden-Württemberg, Germany; Heidelberg University, Faculty of Mathematics and Computer Science, 69120 Heidelberg, Baden-Württemberg, Germany
| | - Oliver Stegle
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany; Division of Computational Genomics and Systems Genetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Baden-Württemberg, Germany
| | - Eileen E M Furlong
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, 69117 Heidelberg, Baden-Württemberg, Germany.
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7
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Global patterns of enhancer activity during sea urchin embryogenesis assessed by eRNA profiling. Genome Res 2021; 31:1680-1692. [PMID: 34330790 PMCID: PMC8415375 DOI: 10.1101/gr.275684.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/28/2021] [Indexed: 11/25/2022]
Abstract
We used capped analysis of gene expression with sequencing (CAGE-seq) to profile eRNA expression and enhancer activity during embryogenesis of a model echinoderm: the sea urchin, Strongylocentrotus purpuratus. We identified more than 18,000 enhancers that were active in mature oocytes and developing embryos and documented a burst of enhancer activation during cleavage and early blastula stages. We found that a large fraction (73.8%) of all enhancers active during the first 48 h of embryogenesis were hyperaccessible no later than the 128-cell stage and possibly even earlier. Most enhancers were located near gene bodies, and temporal patterns of eRNA expression tended to parallel those of nearby genes. Furthermore, enhancers near lineage-specific genes contained signatures of inputs from developmental gene regulatory networks deployed in those lineages. A large fraction (60%) of sea urchin enhancers previously shown to be active in transgenic reporter assays was associated with eRNA expression. Moreover, a large fraction (50%) of a representative subset of enhancers identified by eRNA profiling drove tissue-specific gene expression in isolation when tested by reporter assays. Our findings provide an atlas of developmental enhancers in a model sea urchin and support the utility of eRNA profiling as a tool for enhancer discovery and regulatory biology. The data generated in this study are available at Echinobase, the public database of information related to echinoderm genomics.
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8
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Niederhuber MJ, McKay DJ. Mechanisms underlying the control of dynamic regulatory element activity and chromatin accessibility during metamorphosis. CURRENT OPINION IN INSECT SCIENCE 2021; 43:21-28. [PMID: 32979530 PMCID: PMC7985040 DOI: 10.1016/j.cois.2020.08.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/25/2020] [Indexed: 05/10/2023]
Abstract
Cis-regulatory modules of metazoan genomes determine the when and where of gene expression during development. Here we discuss insights into the genetic and molecular mechanisms behind cis-regulatory module usage that have come from recent application of genomics assays to insect metamorphosis. Assays including FAIRE-seq, ATAC-seq, and CUT&RUN indicate that sequential changes in chromatin accessibility play a key role in mediating stage-specific cis-regulatory module activity and gene expression. We review the current understanding of what controls precisely coordinated changes in chromatin accessibility during metamorphosis and describe evidence that points to systemic hormone signaling as a primary signal to trigger genome-wide shifts in accessibility patterns and cis-regulatory module usage.
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Affiliation(s)
- Matthew J Niederhuber
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Daniel J McKay
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States.
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9
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van der Veeken J, Glasner A, Zhong Y, Hu W, Wang ZM, Bou-Puerto R, Charbonnier LM, Chatila TA, Leslie CS, Rudensky AY. The Transcription Factor Foxp3 Shapes Regulatory T Cell Identity by Tuning the Activity of trans-Acting Intermediaries. Immunity 2020; 53:971-984.e5. [PMID: 33176163 DOI: 10.1016/j.immuni.2020.10.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/06/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022]
Abstract
Regulatory T (Treg) cell identity is defined by the lineage-specifying transcription factor (TF) Foxp3. Here we examined mechanisms of Foxp3 function by leveraging naturally occurring genetic variation in wild-derived inbred mice, which enables the identification of DNA sequence motifs driving epigenetic features. Chromatin accessibility, TF binding, and gene expression patterns in resting and activated subsets of Treg cells, conventional CD4 T cells, and cells expressing a Foxp3 reporter null allele revealed that the majority of Foxp3-dependent changes occurred at sites not bound by Foxp3. Chromatin accessibility of these indirect Foxp3 targets depended on the presence of DNA binding motifs for other TFs, including TCF1. Foxp3 expression correlated with decreased TCF1 and reduced accessibility of TCF1-bound chromatin regions. Deleting one copy of the Tcf7 gene recapitulated Foxp3-dependent negative regulation of chromatin accessibility. Thus, Foxp3 defines Treg cell identity in a largely indirect manner by fine-tuning the activity of other major chromatin remodeling TFs such as TCF1.
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Affiliation(s)
- Joris van der Veeken
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Ariella Glasner
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Yi Zhong
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA; Computational and Systems Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Wei Hu
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Zhong-Min Wang
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA; Gerstner Sloan Kettering Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Regina Bou-Puerto
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Louis-Marie Charbonnier
- Division of Immunology, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Talal A Chatila
- Division of Immunology, Boston Children's Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Christina S Leslie
- Computational and Systems Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alexander Y Rudensky
- Howard Hughes Medical Institute and Immunology Program, Sloan Kettering Institute, and Ludwig Center at Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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10
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McEwan AR, MacKenzie A. Perspective: Quality Versus Quantity; Is It Important to Assess the Role of Enhancers in Complex Disease from an In Vivo Perspective? Int J Mol Sci 2020; 21:E7856. [PMID: 33113946 PMCID: PMC7660172 DOI: 10.3390/ijms21217856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/15/2020] [Accepted: 10/20/2020] [Indexed: 12/18/2022] Open
Abstract
Sequencing of the human genome has permitted the development of genome-wide association studies (GWAS) to analyze the genetics of a number of complex disorders such as depression, anxiety and substance abuse. Thanks to their ability to analyze huge cohort sizes, these studies have successfully identified thousands of loci associated with a broad spectrum of complex diseases. Disconcertingly, the majority of these GWAS hits occur in non-coding regions of the genome, much of which controls the cell-type-specific expression of genes essential to health. In contrast to gene coding sequences, it is a challenge to understand the function of this non-coding regulatory genome using conventional biochemical techniques in cell lines. The current commentary scrutinizes the field of complex genetics from the standpoint of the large-scale whole-genome functional analysis of the promoters and cis-regulatory elements using chromatin markers. We contrast these large scale quantitative techniques against comparative genomics and in vivo analyses including CRISPR/CAS9 genome editing to determine the functional characteristics of these elements and to understand how polymorphic variation and epigenetic changes within these elements might contribute to complex disease and drug response. Most importantly, we suggest that, although the role of chromatin markers will continue to be important in identifying and characterizing enhancers, more emphasis must be placed on their analysis in relevant in-vivo models that take account of the appropriate cell-type-specific roles of these elements. It is hoped that offering these insights might refocus progress in analyzing the data tsunami of non-coding GWAS and whole-genome sequencing "hits" that threatens to overwhelm progress in the field.
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Affiliation(s)
| | - Alasdair MacKenzie
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen AB25 2ZD, UK;
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11
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On the specificity of gene regulatory networks: How does network co-option affect subsequent evolution? Curr Top Dev Biol 2020; 139:375-405. [PMID: 32450967 DOI: 10.1016/bs.ctdb.2020.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The process of multicellular organismal development hinges upon the specificity of developmental programs: for different parts of the organism to form unique features, processes must exist to specify each part. This specificity is thought to be hardwired into gene regulatory networks, which activate cohorts of genes in particular tissues at particular times during development. However, the evolution of gene regulatory networks sometimes occurs by mechanisms that sacrifice specificity. One such mechanism is network co-option, in which existing gene networks are redeployed in new developmental contexts. While network co-option may offer an efficient mechanism for generating novel phenotypes, losses of tissue specificity at redeployed network genes could restrict the ability of the affected traits to evolve independently. At present, there has not been a detailed discussion regarding how tissue specificity of network genes might be altered due to gene network co-option at its initiation, as well as how trait independence can be retained or restored after network co-option. A lack of clarity about network co-option makes it more difficult to speculate on the long-term evolutionary implications of this mechanism. In this review, we will discuss the possible initial outcomes of network co-option, outline the mechanisms by which networks may retain or subsequently regain specificity after network co-option, and comment on some of the possible evolutionary consequences of network co-option. We place special emphasis on the need to consider selectively-neutral outcomes of network co-option to improve our understanding of the role of this mechanism in trait evolution.
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12
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Ryan GE, Farley EK. Functional genomic approaches to elucidate the role of enhancers during development. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1467. [PMID: 31808313 PMCID: PMC7027484 DOI: 10.1002/wsbm.1467] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/02/2019] [Accepted: 10/11/2019] [Indexed: 12/22/2022]
Abstract
Successful development depends on the precise tissue-specific regulation of genes by enhancers, genetic elements that act as switches to control when and where genes are expressed. Because enhancers are critical for development, and the majority of disease-associated mutations reside within enhancers, it is essential to understand which sequences within enhancers are important for function. Advances in sequencing technology have enabled the rapid generation of genomic data that predict putative active enhancers, but functionally validating these sequences at scale remains a fundamental challenge. Herein, we discuss the power of genome-wide strategies used to identify candidate enhancers, and also highlight limitations and misconceptions that have arisen from these data. We discuss the use of massively parallel reporter assays to test enhancers for function at scale. We also review recent advances in our ability to study gene regulation during development, including CRISPR-based tools to manipulate genomes and single-cell transcriptomics to finely map gene expression. Finally, we look ahead to a synthesis of complementary genomic approaches that will advance our understanding of enhancer function during development. This article is categorized under: Physiology > Mammalian Physiology in Health and Disease Developmental Biology > Developmental Processes in Health and Disease Laboratory Methods and Technologies > Genetic/Genomic Methods.
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Affiliation(s)
- Genevieve E. Ryan
- Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
- Division of Biological Sciences, Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
| | - Emma K. Farley
- Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
- Division of Biological Sciences, Department of MedicineUniversity of CaliforniaSan DiegoCalifornia
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13
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Zeiske T, Baburajendran N, Kaczynska A, Brasch J, Palmer AG, Shapiro L, Honig B, Mann RS. Intrinsic DNA Shape Accounts for Affinity Differences between Hox-Cofactor Binding Sites. Cell Rep 2020; 24:2221-2230. [PMID: 30157419 DOI: 10.1016/j.celrep.2018.07.100] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 06/14/2018] [Accepted: 07/28/2018] [Indexed: 11/26/2022] Open
Abstract
Transcription factors bind to their binding sites over a wide range of affinities, yet how differences in affinity are encoded in DNA sequences is not well understood. Here, we report X-ray crystal structures of four heterodimers of the Hox protein AbdominalB bound with its cofactor Extradenticle to four target DNA molecules that differ in affinity by up to ∼20-fold. Remarkably, despite large differences in affinity, the overall structures are very similar in all four complexes. In contrast, the predicted shapes of the DNA binding sites (i.e., the intrinsic DNA shape) in the absence of bound protein are strikingly different from each other and correlate with affinity: binding sites that must change conformations upon protein binding have lower affinities than binding sites that have more optimal conformations prior to binding. Together, these observations suggest that intrinsic differences in DNA shape provide a robust mechanism for modulating affinity without affecting other protein-DNA interactions.
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Affiliation(s)
- Tim Zeiske
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Nithya Baburajendran
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Anna Kaczynska
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Julia Brasch
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Arthur G Palmer
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA; Department of Systems Biology, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| | - Richard S Mann
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA; Department of Systems Biology, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
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14
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Cohen DM, Lim HW, Won KJ, Steger DJ. Shared nucleotide flanks confer transcriptional competency to bZip core motifs. Nucleic Acids Res 2019; 46:8371-8384. [PMID: 30085281 PMCID: PMC6144830 DOI: 10.1093/nar/gky681] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 07/17/2018] [Indexed: 12/31/2022] Open
Abstract
Sequence-specific DNA binding recruits transcription factors (TFs) to the genome to regulate gene expression. Here, we perform high resolution mapping of CEBP proteins to determine how sequence dictates genomic occupancy. We demonstrate a fundamental difference between the sequence repertoire utilized by CEBPs in vivo versus the palindromic sequence preference reported by classical in vitro models, by identifying a palindromic motif at <1% of the genomic binding sites. On the native genome, CEBPs bind a diversity of related 10 bp sequences resulting from the fusion of degenerate and canonical half-sites. Altered DNA specificity of CEBPs in cells occurs through heterodimerization with other bZip TFs, and approximately 40% of CEBP-binding sites in primary human cells harbor motifs characteristic of CEBP heterodimers. In addition, we uncover an important role for sequence bias at core-motif-flanking bases for CEBPs and demonstrate that flanking bases regulate motif function across mammalian bZip TFs. Favorable flanking bases confer efficient TF occupancy and transcriptional activity, and DNA shape may explain how the flanks alter TF binding. Importantly, motif optimization within the 10-mer is strongly correlated with cell-type-independent recruitment of CEBPβ, providing key insight into how sequence sub-optimization affects genomic occupancy of widely expressed CEBPs across cell types.
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Affiliation(s)
- Daniel M Cohen
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.,The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hee-Woong Lim
- The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyoung-Jae Won
- The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.,Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.,Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - David J Steger
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.,The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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15
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Bhakta M, Padanad MS, Harris JP, Lubczyk C, Amatruda JF, Munshi NV. pouC Regulates Expression of bmp4 During Atrioventricular Canal Formation in Zebrafish. Dev Dyn 2018; 248:173-188. [PMID: 30444277 DOI: 10.1002/dvdy.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/04/2018] [Accepted: 10/24/2018] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Many human gene mutations have been linked to congenital heart disease (CHD), yet CHD remains a major health issue worldwide due in part to an incomplete understanding of the molecular basis for cardiac malformation. RESULTS Here we identify the orthologous mouse Pou6f1 and zebrafish pouC as POU homeodomain transcription factors enriched in the developing heart. We find that pouC is a multi-functional transcriptional regulator containing separable activation, repression, protein-protein interaction, and DNA binding domains. Using zebrafish heart development as a model system, we demonstrate that pouC knockdown impairs cardiac morphogenesis and affects cardiovascular function. We also find that levels of pouC expression must be fine-tuned to enable proper heart formation. At the cellular level, we demonstrate that pouC knockdown disrupts atrioventricular canal (AVC) cardiomyocyte maintenance, although chamber myocyte specification remains intact. Mechanistically, we show that pouC binds a bmp4 intronic regulatory element to mediate transcriptional activation. CONCLUSIONS Taken together, our study establishes pouC as a novel transcriptional input into the regulatory hierarchy that drives AVC morphogenesis in zebrafish. We anticipate that these findings will inform future efforts to explore functional conservation in mammals and potential association with atrioventricular septal defects in humans. Developmental Dynamics 248:173-188, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Minoti Bhakta
- Department of Internal Medicine - Cardiology, UT Southwestern Medical Center, Dallas, Texas
| | - Mahesh S Padanad
- Department of Internal Medicine - Cardiology, UT Southwestern Medical Center, Dallas, Texas
| | - John P Harris
- Department of Internal Medicine - Cardiology, UT Southwestern Medical Center, Dallas, Texas
| | - Christina Lubczyk
- Department of Internal Medicine - Cardiology, UT Southwestern Medical Center, Dallas, Texas
| | - James F Amatruda
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas.,Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas
| | - Nikhil V Munshi
- Department of Internal Medicine - Cardiology, UT Southwestern Medical Center, Dallas, Texas.,Department of Molecular Biology, UT Southwestern Medical Center, Dallas, Texas.,McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, Texas.,Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, Texas
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16
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17
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Isoda T, Moore AJ, He Z, Chandra V, Aida M, Denholtz M, Piet van Hamburg J, Fisch KM, Chang AN, Fahl SP, Wiest DL, Murre C. Non-coding Transcription Instructs Chromatin Folding and Compartmentalization to Dictate Enhancer-Promoter Communication and T Cell Fate. Cell 2017; 171:103-119.e18. [PMID: 28938112 DOI: 10.1016/j.cell.2017.09.001] [Citation(s) in RCA: 197] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/24/2017] [Accepted: 08/30/2017] [Indexed: 01/01/2023]
Abstract
It is now established that Bcl11b specifies T cell fate. Here, we show that in developing T cells, the Bcl11b enhancer repositioned from the lamina to the nuclear interior. Our search for factors that relocalized the Bcl11b enhancer identified a non-coding RNA named ThymoD (thymocyte differentiation factor). ThymoD-deficient mice displayed a block at the onset of T cell development and developed lymphoid malignancies. We found that ThymoD transcription promoted demethylation at CTCF bound sites and activated cohesin-dependent looping to reposition the Bcl11b enhancer from the lamina to the nuclear interior and to juxtapose the Bcl11b enhancer and promoter into a single-loop domain. These large-scale changes in nuclear architecture were associated with the deposition of activating epigenetic marks across the loop domain, plausibly facilitating phase separation. These data indicate how, during developmental progression and tumor suppression, non-coding transcription orchestrates chromatin folding and compartmentalization to direct with high precision enhancer-promoter communication.
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Affiliation(s)
- Takeshi Isoda
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Amanda J Moore
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Zhaoren He
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Vivek Chandra
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Masatoshi Aida
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Matthew Denholtz
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jan Piet van Hamburg
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kathleen M Fisch
- Center for Computational Biology & Bioinformatics, Institute for Genomic Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Aaron N Chang
- Center for Computational Biology & Bioinformatics, Institute for Genomic Medicine, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Shawn P Fahl
- Blood Cell Development and Function, Fox Chase Cancer Center, 333 Cottman Avenue, PA, Philadelphia, PA 19111, USA
| | - David L Wiest
- Blood Cell Development and Function, Fox Chase Cancer Center, 333 Cottman Avenue, PA, Philadelphia, PA 19111, USA
| | - Cornelis Murre
- Department of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA.
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