1
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Ordoñez R, Zhang W, Ellis G, Zhu Y, Ashe HJ, Ribeiro-Dos-Santos AM, Brosh R, Huang E, Hogan MS, Boeke JD, Maurano MT. Genomic context sensitizes regulatory elements to genetic disruption. Mol Cell 2024; 84:1842-1854.e7. [PMID: 38759624 PMCID: PMC11104518 DOI: 10.1016/j.molcel.2024.04.013] [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: 10/10/2023] [Revised: 03/11/2024] [Accepted: 04/18/2024] [Indexed: 05/19/2024]
Abstract
Genomic context critically modulates regulatory function but is difficult to manipulate systematically. The murine insulin-like growth factor 2 (Igf2)/H19 locus is a paradigmatic model of enhancer selectivity, whereby CTCF occupancy at an imprinting control region directs downstream enhancers to activate either H19 or Igf2. We used synthetic regulatory genomics to repeatedly replace the native locus with 157-kb payloads, and we systematically dissected its architecture. Enhancer deletion and ectopic delivery revealed previously uncharacterized long-range regulatory dependencies at the native locus. Exchanging the H19 enhancer cluster with the Sox2 locus control region (LCR) showed that the H19 enhancers relied on their native surroundings while the Sox2 LCR functioned autonomously. Analysis of regulatory DNA actuation across cell types revealed that these enhancer clusters typify broader classes of context sensitivity genome wide. These results show that unexpected dependencies influence even well-studied loci, and our approach permits large-scale manipulation of complete loci to investigate the relationship between regulatory architecture and function.
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Affiliation(s)
- Raquel Ordoñez
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Weimin Zhang
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Gwen Ellis
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Yinan Zhu
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Hannah J Ashe
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | | | - Ran Brosh
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Emily Huang
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Megan S Hogan
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Jef D Boeke
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA; Department of Biochemistry Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Matthew T Maurano
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA; Department of Pathology, NYU School of Medicine, New York, NY 10016, USA.
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2
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Ordoñez R, Zhang W, Ellis G, Zhu Y, Ashe HJ, Ribeiro-dos-Santos AM, Brosh R, Huang E, Hogan MS, Boeke JD, Maurano MT. Genomic context sensitizes regulatory elements to genetic disruption. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.07.02.547201. [PMID: 37781588 PMCID: PMC10541140 DOI: 10.1101/2023.07.02.547201] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Enhancer function is frequently investigated piecemeal using truncated reporter assays or single deletion analysis. Thus it remains unclear to what extent enhancer function at native loci relies on surrounding genomic context. Using the Big-IN technology for targeted integration of large DNAs, we analyzed the regulatory architecture of the murine Igf2/H19 locus, a paradigmatic model of enhancer selectivity. We assembled payloads containing a 157-kb functional Igf2/H19 locus and engineered mutations to genetically direct CTCF occupancy at the imprinting control region (ICR) that switches the target gene of the H19 enhancer cluster. Contrasting activity of payloads delivered at the endogenous Igf2/H19 locus or ectopically at Hprt revealed that the Igf2/H19 locus includes additional, previously unknown long-range regulatory elements. Exchanging components of the Igf2/H19 locus with the well-studied Sox2 locus showed that the H19 enhancer cluster functioned poorly out of context, and required its native surroundings to activate Sox2 expression. Conversely, the Sox2 locus control region (LCR) could activate both Igf2 and H19 outside its native context, but its activity was only partially modulated by CTCF occupancy at the ICR. Analysis of regulatory DNA actuation across different cell types revealed that, while the H19 enhancers are tightly coordinated within their native locus, the Sox2 LCR acts more independently. We show that these enhancer clusters typify broader classes of loci genome-wide. Our results show that unexpected dependencies may influence even the most studied functional elements, and our synthetic regulatory genomics approach permits large-scale manipulation of complete loci to investigate the relationship between locus architecture and function.
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Affiliation(s)
- Raquel Ordoñez
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- These authors contributed equally
| | - Weimin Zhang
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- These authors contributed equally
| | - Gwen Ellis
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- Present address: Department of Biology, University of Vermont, Burlington, VT 05405, USA
| | - Yinan Zhu
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Hannah J. Ashe
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- Present address: School of Medicine, University of Maryland, Baltimore, MD 21201, USA
| | | | - Ran Brosh
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Emily Huang
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- Present address: Highmark Health, Pittsburgh, PA 15222, USA
| | - Megan S. Hogan
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- Present address: Neochromosome Inc., Long Island City, NY 11101, USA
| | - Jef D. Boeke
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- Department of Biochemistry Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Matthew T. Maurano
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
- Department of Pathology, NYU School of Medicine, New York, NY 10016, USA
- Lead contact
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3
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Panten J, Heinen T, Ernst C, Eling N, Wagner RE, Satorius M, Marioni JC, Stegle O, Odom DT. The dynamic genetic determinants of increased transcriptional divergence in spermatids. Nat Commun 2024; 15:1272. [PMID: 38341412 PMCID: PMC10858866 DOI: 10.1038/s41467-024-45133-1] [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: 02/07/2023] [Accepted: 01/16/2024] [Indexed: 02/12/2024] Open
Abstract
Cis-genetic effects are key determinants of transcriptional divergence in discrete tissues and cell types. However, how cis- and trans-effects act across continuous trajectories of cellular differentiation in vivo is poorly understood. Here, we quantify allele-specific expression during spermatogenic differentiation at single-cell resolution in an F1 hybrid mouse system, allowing for the comprehensive characterisation of cis- and trans-genetic effects, including their dynamics across cellular differentiation. Collectively, almost half of the genes subject to genetic regulation show evidence for dynamic cis-effects that vary during differentiation. Our system also allows us to robustly identify dynamic trans-effects, which are less pervasive than cis-effects. In aggregate, genetic effects were strongest in round spermatids, which parallels their increased transcriptional divergence we identified between species. Our approach provides a comprehensive quantification of the variability of genetic effects in vivo, and demonstrates a widely applicable strategy to dissect the impact of regulatory variants on gene regulation in dynamic systems.
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Affiliation(s)
- Jasper Panten
- Division of Regulatory Genomics and Cancer Evolution, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany
- Division of Computational Genomics and Systems Genetics, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, 69117, Heidelberg, Germany
| | - Tobias Heinen
- Division of Computational Genomics and Systems Genetics, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany
- Faculty of Mathematics and Computer Science, Heidelberg University, Heidelberg, Germany
- European Molecular Biology Laboratory, Genome Biology Unit, 69117, Heidelberg, Germany
| | - Christina Ernst
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Nils Eling
- University of Zurich, Department of Quantitative Biomedicine, Zurich, 8057, Switzerland
- ETH Zurich, Institute for Molecular Health Sciences, Zurich, 8093, Switzerland
| | - Rebecca E Wagner
- Faculty of Biosciences, Heidelberg University, 69117, Heidelberg, Germany
- Division of Mechanisms Regulating Gene Expression, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany
| | - Maja Satorius
- Division of Regulatory Genomics and Cancer Evolution, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany
| | - John C Marioni
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Cambridge, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Oliver Stegle
- Division of Computational Genomics and Systems Genetics, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany.
- European Molecular Biology Laboratory, Genome Biology Unit, 69117, Heidelberg, Germany.
| | - Duncan T Odom
- Division of Regulatory Genomics and Cancer Evolution, German Cancer Research Centre (DKFZ), 69120, Heidelberg, Germany.
- Faculty of Biosciences, Heidelberg University, 69117, Heidelberg, Germany.
- Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK.
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4
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Brosh R, Coelho C, Ribeiro-Dos-Santos AM, Ellis G, Hogan MS, Ashe HJ, Somogyi N, Ordoñez R, Luther RD, Huang E, Boeke JD, Maurano MT. Synthetic regulatory genomics uncovers enhancer context dependence at the Sox2 locus. Mol Cell 2023; 83:1140-1152.e7. [PMID: 36931273 PMCID: PMC10081970 DOI: 10.1016/j.molcel.2023.02.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/20/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023]
Abstract
Sox2 expression in mouse embryonic stem cells (mESCs) depends on a distal cluster of DNase I hypersensitive sites (DHSs), but their individual contributions and degree of interdependence remain a mystery. We analyzed the endogenous Sox2 locus using Big-IN to scarlessly integrate large DNA payloads incorporating deletions, rearrangements, and inversions affecting single or multiple DHSs, as well as surgical alterations to transcription factor (TF) recognition sequences. Multiple mESC clones were derived for each payload, sequence-verified, and analyzed for Sox2 expression. We found that two DHSs comprising a handful of key TF recognition sequences were each sufficient for long-range activation of Sox2 expression. By contrast, three nearby DHSs were entirely context dependent, showing no activity alone but dramatically augmenting the activity of the autonomous DHSs. Our results highlight the role of context in modulating genomic regulatory element function, and our synthetic regulatory genomics approach provides a roadmap for the dissection of other genomic loci.
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Affiliation(s)
- Ran Brosh
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Camila Coelho
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | | | - Gwen Ellis
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Megan S Hogan
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Hannah J Ashe
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Nicolette Somogyi
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Raquel Ordoñez
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Raven D Luther
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Emily Huang
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA
| | - Jef D Boeke
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA; Department of Biochemistry Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA; Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY 11201, USA
| | - Matthew T Maurano
- Institute for Systems Genetics, NYU School of Medicine, New York, NY 10016, USA; Department of Pathology, NYU School of Medicine, New York, NY 10016, USA.
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5
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Golovina E, Fadason T, Jaros RK, Kumar H, John J, Burrowes K, Tawhai M, O'Sullivan JM. De novo discovery of traits co-occurring with chronic obstructive pulmonary disease. Life Sci Alliance 2023; 6:6/3/e202201609. [PMID: 36574990 PMCID: PMC9795035 DOI: 10.26508/lsa.202201609] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/28/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a heterogeneous group of chronic lung conditions. Genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) associated with COPD and the co-occurring conditions, suggesting common biological mechanisms underlying COPD and these co-occurring conditions. To identify them, we have integrated information across different biological levels (i.e., genetic variants, lung-specific 3D genome structure, gene expression and protein-protein interactions) to build lung-specific gene regulatory and protein-protein interaction networks. We have queried these networks using disease-associated SNPs for COPD, unipolar depression and coronary artery disease. COPD-associated SNPs can control genes involved in the regulation of lung or pulmonary function, asthma, brain region volumes, cortical surface area, depressed affect, neuroticism, Parkinson's disease, white matter microstructure and smoking behaviour. We describe the regulatory connections, genes and biochemical pathways that underlay these co-occurring trait-SNP-gene associations. Collectively, our findings provide new avenues for the investigation of the underlying biology and diverse clinical presentations of COPD. In so doing, we identify a collection of genetic variants and genes that may aid COPD patient stratification and treatment.
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Affiliation(s)
| | - Tayaza Fadason
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand
| | - Rachel K Jaros
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Haribalan Kumar
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Joyce John
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Kelly Burrowes
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Merryn Tawhai
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Justin M O'Sullivan
- Liggins Institute, University of Auckland, Auckland, New Zealand .,Maurice Wilkins Centre, University of Auckland, Auckland, New Zealand.,MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, UK.,Garvan Institute of Medical Research, Sydney, Australia.,Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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6
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Yang MG, Ling E, Cowley CJ, Greenberg ME, Vierbuchen T. Characterization of sequence determinants of enhancer function using natural genetic variation. eLife 2022; 11:76500. [PMID: 36043696 PMCID: PMC9662815 DOI: 10.7554/elife.76500] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 08/30/2022] [Indexed: 02/04/2023] Open
Abstract
Sequence variation in enhancers that control cell-type-specific gene transcription contributes significantly to phenotypic variation within human populations. However, it remains difficult to predict precisely the effect of any given sequence variant on enhancer function due to the complexity of DNA sequence motifs that determine transcription factor (TF) binding to enhancers in their native genomic context. Using F1-hybrid cells derived from crosses between distantly related inbred strains of mice, we identified thousands of enhancers with allele-specific TF binding and/or activity. We find that genetic variants located within the central region of enhancers are most likely to alter TF binding and enhancer activity. We observe that the AP-1 family of TFs (Fos/Jun) are frequently required for binding of TEAD TFs and for enhancer function. However, many sequence variants outside of core motifs for AP-1 and TEAD also impact enhancer function, including sequences flanking core TF motifs and AP-1 half sites. Taken together, these data represent one of the most comprehensive assessments of allele-specific TF binding and enhancer function to date and reveal how sequence changes at enhancers alter their function across evolutionary timescales.
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Affiliation(s)
- Marty G Yang
- Department of Neurobiology, Harvard Medical School, Boston, United States.,Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Emi Ling
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | | | | | - Thomas Vierbuchen
- Developmental Biology Program, Sloan Kettering Institute for Cancer Research, New York, United States.,Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, United States
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7
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Krieger G, Lupo O, Wittkopp P, Barkai N. Evolution of transcription factor binding through sequence variations and turnover of binding sites. Genome Res 2022; 32:1099-1111. [PMID: 35618416 DOI: 10.1101/gr.276715.122] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/20/2022] [Indexed: 01/08/2023]
Abstract
Variations in noncoding regulatory sequences play a central role in evolution. Interpreting such variations, however, remains difficult even in the context of defined attributes such as transcription factor (TF) binding sites. Here, we systematically link variations in cis-regulatory sequences to TF binding by profiling the allele-specific binding of 27 TFs expressed in a yeast hybrid, in which two related genomes are present within the same nucleus. TFs localize preferentially to sites containing their known consensus motifs but occupy only a small fraction of the motif-containing sites available within the genomes. Differential binding of TFs to the orthologous alleles was well explained by variations that alter motif sequence, whereas differences in chromatin accessibility between alleles were of little apparent effect. Motif variations that abolished binding when present in only one allele were still bound when present in both alleles, suggesting evolutionary compensation, with a potential role for sequence conservation at the motif's vicinity. At the level of the full promoter, we identify cases of binding-site turnover, in which binding sites are reciprocally gained and lost, yet most interspecific differences remained uncompensated. Our results show the flexibility of TFs to bind imprecise motifs and the fast evolution of TF binding sites between related species.
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Affiliation(s)
- Gat Krieger
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Offir Lupo
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Patricia Wittkopp
- Department of Ecology and Evolutionary Biology, Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Naama Barkai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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8
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Ribeiro-Dos-Santos AM, Hogan MS, Luther RD, Brosh R, Maurano MT. Genomic context sensitivity of insulator function. Genome Res 2022; 32:425-436. [PMID: 35082140 PMCID: PMC8896466 DOI: 10.1101/gr.276449.121] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/25/2022] [Indexed: 11/24/2022]
Abstract
The specificity of interactions between genomic regulatory elements and potential target genes is influenced by the binding of insulator proteins such as CTCF, which can act as potent enhancer blockers when interposed between an enhancer and a promoter in a reporter assay. But not all CTCF sites genome-wide function as insulator elements, depending on cellular and genomic context. To dissect the influence of genomic context on enhancer blocker activity, we integrated reporter constructs with promoter-only, promoter and enhancer, and enhancer blocker configurations at hundreds of thousands of genomic sites using the Sleeping Beauty transposase. Deconvolution of reporter activity by genomic position reveals distinct expression patterns subject to genomic context, including a compartment of enhancer blocker reporter integrations with robust expression. The high density of integration sites permits quantitative delineation of characteristic genomic context sensitivity profiles and their decomposition into sensitivity to both local and distant DNase I hypersensitive sites. Furthermore, using a single-cell expression approach to test the effect of integrated reporters for differential expression of nearby endogenous genes reveals that CTCF insulator elements do not completely abrogate reporter effects on endogenous gene expression. Collectively, our results lend new insight into genomic regulatory compartmentalization and its influence on the determinants of promoter–enhancer specificity.
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Affiliation(s)
| | - Megan S Hogan
- Institute for Systems Genetics, NYU Grossman School of Medicine
| | - Raven D Luther
- Institute for Systems Genetics, NYU Grossman School of Medicine
| | - Ran Brosh
- Institute for Systems Genetics, NYU Grossman School of Medicine
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9
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Srinivasan C, Phan BN, Lawler AJ, Ramamurthy E, Kleyman M, Brown AR, Kaplow IM, Wirthlin ME, Pfenning AR. Addiction-Associated Genetic Variants Implicate Brain Cell Type- and Region-Specific Cis-Regulatory Elements in Addiction Neurobiology. J Neurosci 2021; 41:9008-9030. [PMID: 34462306 PMCID: PMC8549541 DOI: 10.1523/jneurosci.2534-20.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 06/18/2021] [Accepted: 07/10/2021] [Indexed: 12/14/2022] Open
Abstract
Recent large genome-wide association studies have identified multiple confident risk loci linked to addiction-associated behavioral traits. Most genetic variants linked to addiction-associated traits lie in noncoding regions of the genome, likely disrupting cis-regulatory element (CRE) function. CREs tend to be highly cell type-specific and may contribute to the functional development of the neural circuits underlying addiction. Yet, a systematic approach for predicting the impact of risk variants on the CREs of specific cell populations is lacking. To dissect the cell types and brain regions underlying addiction-associated traits, we applied stratified linkage disequilibrium score regression to compare genome-wide association studies to genomic regions collected from human and mouse assays for open chromatin, which is associated with CRE activity. We found enrichment of addiction-associated variants in putative CREs marked by open chromatin in neuronal (NeuN+) nuclei collected from multiple prefrontal cortical areas and striatal regions known to play major roles in reward and addiction. To further dissect the cell type-specific basis of addiction-associated traits, we also identified enrichments in human orthologs of open chromatin regions of female and male mouse neuronal subtypes: cortical excitatory, D1, D2, and PV. Last, we developed machine learning models to predict mouse cell type-specific open chromatin, enabling us to further categorize human NeuN+ open chromatin regions into cortical excitatory or striatal D1 and D2 neurons and predict the functional impact of addiction-associated genetic variants. Our results suggest that different neuronal subtypes within the reward system play distinct roles in the variety of traits that contribute to addiction.SIGNIFICANCE STATEMENT We combine statistical genetic and machine learning techniques to find that the predisposition to for nicotine, alcohol, and cannabis use behaviors can be partially explained by genetic variants in conserved regulatory elements within specific brain regions and neuronal subtypes of the reward system. Our computational framework can flexibly integrate open chromatin data across species to screen for putative causal variants in a cell type- and tissue-specific manner for numerous complex traits.
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Affiliation(s)
- Chaitanya Srinivasan
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - BaDoi N Phan
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
- Medical Scientist Training Program, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213
| | - Alyssa J Lawler
- Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Easwaran Ramamurthy
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Michael Kleyman
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Ashley R Brown
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Irene M Kaplow
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Morgan E Wirthlin
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
| | - Andreas R Pfenning
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
- Department of Biological Sciences, Mellon College of Science, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
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