1
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Kawasaki K, Fukaya T. Regulatory landscape of enhancer-mediated transcriptional activation. Trends Cell Biol 2024; 34:826-837. [PMID: 38355349 DOI: 10.1016/j.tcb.2024.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/21/2023] [Accepted: 01/22/2024] [Indexed: 02/16/2024]
Abstract
Enhancers are noncoding regulatory elements that instruct spatial and temporal specificity of gene transcription in response to a variety of intrinsic and extrinsic signals during development. Although it has long been postulated that enhancers physically interact with target promoters through the formation of stable loops, recent studies have changed this static view: sequence-specific transcription factors (TFs) and coactivators are dynamically recruited to enhancers and assemble so-called transcription hubs. Dynamic assembly of transcription hubs appears to serve as a key scaffold to integrate regulatory information encoded by surrounding genome and biophysical properties of transcription machineries. In this review, we outline emerging new models of transcriptional regulation by enhancers and discuss future perspectives.
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Affiliation(s)
- Koji Kawasaki
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Takashi Fukaya
- Laboratory of Transcription Dynamics, Research Center for Biological Visualization, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan.
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2
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McDonald JMC, Reed RD. Beyond modular enhancers: new questions in cis-regulatory evolution. Trends Ecol Evol 2024:S0169-5347(24)00170-8. [PMID: 39266441 DOI: 10.1016/j.tree.2024.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 06/28/2024] [Accepted: 07/08/2024] [Indexed: 09/14/2024]
Abstract
Our understanding of how cis-regulatory elements work has advanced rapidly, outpacing our evolutionary models. In this review, we consider the implications of new mechanistic findings for evolutionary developmental biology. We focus on three different debates: whether evolutionary innovation occurs more often via the modification of old cis-regulatory elements or the emergence of new ones; the extent to which individual elements are specific and autonomous or multifunctional and interdependent; and how the robustness of cis-regulatory architectures influences the rate of trait evolution. These discussions lead us to propose new questions for the evo-devo of cis-regulation.
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Affiliation(s)
- Jeanne M C McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA.
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
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3
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Chai C, Gibson J, Li P, Pampari A, Patel A, Kundaje A, Wang B. Flexible use of conserved motif vocabularies constrains genome access in cell type evolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.03.611027. [PMID: 39282369 PMCID: PMC11398382 DOI: 10.1101/2024.09.03.611027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Cell types evolve into a hierarchy with related types grouped into families. How cell type diversification is constrained by the stable separation between families over vast evolutionary times remains unknown. Here, integrating single-nucleus multiomic sequencing and deep learning, we show that hundreds of sequence features (motifs) divide into distinct sets associated with accessible genomes of specific cell type families. This division is conserved across highly divergent, early-branching animals including flatworms and cnidarians. While specific interactions between motifs delineate cell type relationships within families, surprisingly, these interactions are not conserved between species. Consistently, while deep learning models trained on one species can predict accessibility of other species' sequences, their predictions frequently rely on distinct, but synonymous, motif combinations. We propose that long-term stability of cell type families is maintained through genome access specified by conserved motif sets, or 'vocabularies', whereas cell types diversify through flexible use of motifs within each set.
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Affiliation(s)
- Chew Chai
- Department of Bioengineering, Stanford University, Stanford, USA
| | - Jesse Gibson
- Department of Bioengineering, Stanford University, Stanford, USA
| | - Pengyang Li
- Department of Bioengineering, Stanford University, Stanford, USA
| | - Anusri Pampari
- Department of Computer Science, Stanford University, Stanford, USA
| | - Aman Patel
- Department of Computer Science, Stanford University, Stanford, USA
| | - Anshul Kundaje
- Department of Computer Science, Stanford University, Stanford, USA
- Department of Genetics, Stanford University School of Medicine, Stanford, USA
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, USA
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, USA
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4
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Li XC, Srinivasan V, Laiker I, Misunou N, Frankel N, Pallares LF, Crocker J. TF-High-Evolutionary: In Vivo Mutagenesis of Gene Regulatory Networks for the Study of the Genetics and Evolution of the Drosophila Regulatory Genome. Mol Biol Evol 2024; 41:msae167. [PMID: 39117360 PMCID: PMC11342961 DOI: 10.1093/molbev/msae167] [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: 04/25/2024] [Revised: 07/29/2024] [Accepted: 08/06/2024] [Indexed: 08/10/2024] Open
Abstract
Understanding the evolutionary potential of mutations in gene regulatory networks is essential to furthering the study of evolution and development. However, in multicellular systems, genetic manipulation of regulatory networks in a targeted and high-throughput way remains challenging. In this study, we designed TF-High-Evolutionary (HighEvo), a transcription factor (TF) fused with a base editor (activation-induced deaminase), to continuously induce germline mutations at TF-binding sites across regulatory networks in Drosophila. Populations of flies expressing TF-HighEvo in their germlines accumulated mutations at rates an order of magnitude higher than natural populations. Importantly, these mutations accumulated around the targeted TF-binding sites across the genome, leading to distinct morphological phenotypes consistent with the developmental roles of the tagged TFs. As such, this TF-HighEvo method allows the interrogation of the mutational space of gene regulatory networks at scale and can serve as a powerful reagent for experimental evolution and genetic screens focused on the regulatory genome.
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Affiliation(s)
- Xueying C Li
- European Molecular Biology Laboratory, Heidelberg, Germany
| | | | - Ian Laiker
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad de Buenos Aires (UBA), Buenos Aires 1428, Argentina
| | | | - Nicolás Frankel
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad de Buenos Aires (UBA), Buenos Aires 1428, Argentina
| | - Luisa F Pallares
- Friedrich Miescher Laboratory, Max Planck Society, Tübingen, Germany
| | - Justin Crocker
- European Molecular Biology Laboratory, Heidelberg, Germany
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5
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Lalanne JB, Regalado SG, Domcke S, Calderon D, Martin BK, Li X, Li T, Suiter CC, Lee C, Trapnell C, Shendure J. Multiplex profiling of developmental cis-regulatory elements with quantitative single-cell expression reporters. Nat Methods 2024; 21:983-993. [PMID: 38724692 PMCID: PMC11166576 DOI: 10.1038/s41592-024-02260-3] [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: 01/06/2023] [Accepted: 03/22/2024] [Indexed: 06/13/2024]
Abstract
The inability to scalably and precisely measure the activity of developmental cis-regulatory elements (CREs) in multicellular systems is a bottleneck in genomics. Here we develop a dual RNA cassette that decouples the detection and quantification tasks inherent to multiplex single-cell reporter assays. The resulting measurement of reporter expression is accurate over multiple orders of magnitude, with a precision approaching the limit set by Poisson counting noise. Together with RNA barcode stabilization via circularization, these scalable single-cell quantitative expression reporters provide high-contrast readouts, analogous to classic in situ assays but entirely from sequencing. Screening >200 regions of accessible chromatin in a multicellular in vitro model of early mammalian development, we identify 13 (8 previously uncharacterized) autonomous and cell-type-specific developmental CREs. We further demonstrate that chimeric CRE pairs generate cognate two-cell-type activity profiles and assess gain- and loss-of-function multicellular expression phenotypes from CRE variants with perturbed transcription factor binding sites. Single-cell quantitative expression reporters can be applied in developmental and multicellular systems to quantitatively characterize native, perturbed and synthetic CREs at scale, with high sensitivity and at single-cell resolution.
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Affiliation(s)
| | - Samuel G Regalado
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Silvia Domcke
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Diego Calderon
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Beth K Martin
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Xiaoyi Li
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Tony Li
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Chase C Suiter
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA, USA
| | - Choli Lee
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Cole Trapnell
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA
- Allen Discovery Center for Cell Lineage Tracing, Seattle, WA, USA
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA.
- Allen Discovery Center for Cell Lineage Tracing, Seattle, WA, USA.
- Howard Hughes Medical Institute, Seattle, WA, USA.
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6
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Li XC, Gandara L, Ekelöf M, Richter K, Alexandrov T, Crocker J. Rapid response of fly populations to gene dosage across development and generations. Nat Commun 2024; 15:4551. [PMID: 38811562 PMCID: PMC11137061 DOI: 10.1038/s41467-024-48960-4] [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: 09/06/2023] [Accepted: 05/17/2024] [Indexed: 05/31/2024] Open
Abstract
Although the effects of genetic and environmental perturbations on multicellular organisms are rarely restricted to single phenotypic layers, our current understanding of how developmental programs react to these challenges remains limited. Here, we have examined the phenotypic consequences of disturbing the bicoid regulatory network in early Drosophila embryos. We generated flies with two extra copies of bicoid, which causes a posterior shift of the network's regulatory outputs and a decrease in fitness. We subjected these flies to EMS mutagenesis, followed by experimental evolution. After only 8-15 generations, experimental populations have normalized patterns of gene expression and increased survival. Using a phenomics approach, we find that populations were normalized through rapid increases in embryo size driven by maternal changes in metabolism and ovariole development. We extend our results to additional populations of flies, demonstrating predictability. Together, our results necessitate a broader view of regulatory network evolution at the systems level.
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Affiliation(s)
- Xueying C Li
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
- College of Life Sciences, Beijing Normal University, Beijing, China.
| | - Lautaro Gandara
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Måns Ekelöf
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Kerstin Richter
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Theodore Alexandrov
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Molecular Medicine Partnership Unit between EMBL and Heidelberg University, Heidelberg, Germany
- BioInnovation Institute, Copenhagen, Denmark
| | - Justin Crocker
- European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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7
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Alfonso-Gonzalez C, Hilgers V. (Alternative) transcription start sites as regulators of RNA processing. Trends Cell Biol 2024:S0962-8924(24)00033-3. [PMID: 38531762 DOI: 10.1016/j.tcb.2024.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/20/2024] [Accepted: 02/23/2024] [Indexed: 03/28/2024]
Abstract
Alternative transcription start site usage (ATSS) is a widespread regulatory strategy that enables genes to choose between multiple genomic loci for initiating transcription. This mechanism is tightly controlled during development and is often altered in disease states. In this review, we examine the growing evidence highlighting a role for transcription start sites (TSSs) in the regulation of mRNA isoform selection during and after transcription. We discuss how the choice of transcription initiation sites influences RNA processing and the importance of this crosstalk for cell identity and organism function. We also speculate on possible mechanisms underlying the integration of transcriptional and post-transcriptional processes.
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Affiliation(s)
- Carlos Alfonso-Gonzalez
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany; Faculty of Biology, Albert Ludwigs University, 79104 Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology (IMPRS- MCB), 79108 Freiburg, Germany
| | - Valérie Hilgers
- Max Planck Institute of Immunobiology and Epigenetics, 79108 Freiburg, Germany.
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8
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Shen Y, Shi K, Li D, Wang Q, Wu K, Feng C. Prognostic analysis of mutated genes and insight into effects of DNA damage and repair on mutational strand asymmetries in gastric cancer. Biochem Biophys Rep 2024; 37:101597. [PMID: 38371526 PMCID: PMC10873876 DOI: 10.1016/j.bbrep.2023.101597] [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: 08/09/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 02/20/2024] Open
Abstract
Gastric cancer (GACA) is a complex and multifaceted disease influenced by a variety of environmental and genetic factors. Somatic mutations play a major role in its development, and their characteristics, including the asymmetry between two DNA strands, are of great interest and appear as a signal of information and guidance, revealing mechanisms of DNA damage and repair. Here, we analyzed the impact of High-frequency mutated genes on patient prognosis and found that the effect of expression levels of tumor protein p53 (TP53) and lysine methyltransferase 2C (KMT2C) genes remained high throughout the development of GACA, with similar expression patterns. After investigating mutation asymmetry across mutagenic processes, we found that transcriptional asymmetry was dominated by T > G mutations under the influence of transcription couples repair and damage. The apolipoprotein B mRNA editing enzyme catalytic polypeptide like (APOBEC) enzyme that induces mutations during DNA replication has been identified here and we identified a replicative asymmetry, which was dominated by C > A mutations in left-replicating. Strand bias in different mutation classes at transcription factor binding sites and enhancer regions were also confirmed, which implies the important role of non-coding regulatory elements in the occurrence of mutations. This work systematically describes mutational strand asymmetries in specific genomic regions, shedding light on the DNA damage and repair mechanisms underlying somatic mutations in cohorts of GACA patients with gastric cancer.
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Affiliation(s)
- Yangyang Shen
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
- Institute of Animal Science, Jiangsu Academy of Agriculture Science, Nanjing, China
| | - Kai Shi
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Dongfeng Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Qiang Wang
- Department of Urology, Peking University People's Hospital, Beijing, China
| | - Kangkang Wu
- Department of Infectious Disease, Children's Hospital of Nanjing Medical University, Nanjing, China
| | - Chungang Feng
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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9
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Mold JE, Weissman MH, Ratz M, Hagemann-Jensen M, Hård J, Eriksson CJ, Toosi H, Berghenstråhle J, Ziegenhain C, von Berlin L, Martin M, Blom K, Lagergren J, Lundeberg J, Sandberg R, Michaëlsson J, Frisén J. Clonally heritable gene expression imparts a layer of diversity within cell types. Cell Syst 2024; 15:149-165.e10. [PMID: 38340731 DOI: 10.1016/j.cels.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 05/25/2023] [Accepted: 01/18/2024] [Indexed: 02/12/2024]
Abstract
Cell types can be classified according to shared patterns of transcription. Non-genetic variability among individual cells of the same type has been ascribed to stochastic transcriptional bursting and transient cell states. Using high-coverage single-cell RNA profiling, we asked whether long-term, heritable differences in gene expression can impart diversity within cells of the same type. Studying clonal human lymphocytes and mouse brain cells, we uncovered a vast diversity of heritable gene expression patterns among different clones of cells of the same type in vivo. We combined chromatin accessibility and RNA profiling on different lymphocyte clones to reveal thousands of regulatory regions exhibiting interclonal variation, which could be directly linked to interclonal variation in gene expression. Our findings identify a source of cellular diversity, which may have important implications for how cellular populations are shaped by selective processes in development, aging, and disease. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Jeff E Mold
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Martin H Weissman
- Mathematics Department, University of California, Santa Cruz, CA, USA.
| | - Michael Ratz
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden; SciLifeLab, Department of Gene Technology, KTH Royal Institute of Technology, Stockholm, Sweden
| | | | - Joanna Hård
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Carl-Johan Eriksson
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Hosein Toosi
- SciLifeLab, Computational Science and Technology Department, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Joseph Berghenstråhle
- SciLifeLab, Department of Gene Technology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Christoph Ziegenhain
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Leonie von Berlin
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Marcel Martin
- Department of Biochemistry and Biophysics, National Bioinformatics Infrastructure Sweden, SciLifeLab, Stockholm University, Stockholm, Sweden
| | - Kim Blom
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institute, Stockholm, Sweden
| | - Jens Lagergren
- SciLifeLab, Computational Science and Technology Department, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Joakim Lundeberg
- SciLifeLab, Department of Gene Technology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Rickard Sandberg
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Jakob Michaëlsson
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institute, Stockholm, Sweden.
| | - Jonas Frisén
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
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10
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Taskiran II, Spanier KI, Dickmänken H, Kempynck N, Pančíková A, Ekşi EC, Hulselmans G, Ismail JN, Theunis K, Vandepoel R, Christiaens V, Mauduit D, Aerts S. Cell-type-directed design of synthetic enhancers. Nature 2024; 626:212-220. [PMID: 38086419 PMCID: PMC10830415 DOI: 10.1038/s41586-023-06936-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 12/05/2023] [Indexed: 01/19/2024]
Abstract
Transcriptional enhancers act as docking stations for combinations of transcription factors and thereby regulate spatiotemporal activation of their target genes1. It has been a long-standing goal in the field to decode the regulatory logic of an enhancer and to understand the details of how spatiotemporal gene expression is encoded in an enhancer sequence. Here we show that deep learning models2-6, can be used to efficiently design synthetic, cell-type-specific enhancers, starting from random sequences, and that this optimization process allows detailed tracing of enhancer features at single-nucleotide resolution. We evaluate the function of fully synthetic enhancers to specifically target Kenyon cells or glial cells in the fruit fly brain using transgenic animals. We further exploit enhancer design to create 'dual-code' enhancers that target two cell types and minimal enhancers smaller than 50 base pairs that are fully functional. By examining the state space searches towards local optima, we characterize enhancer codes through the strength, combination and arrangement of transcription factor activator and transcription factor repressor motifs. Finally, we apply the same strategies to successfully design human enhancers, which adhere to enhancer rules similar to those of Drosophila enhancers. Enhancer design guided by deep learning leads to better understanding of how enhancers work and shows that their code can be exploited to manipulate cell states.
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Affiliation(s)
- Ibrahim I Taskiran
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Katina I Spanier
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Hannah Dickmänken
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Niklas Kempynck
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Alexandra Pančíková
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
- VIB-KULeuven Center for Cancer Biology, Leuven, Belgium
| | - Eren Can Ekşi
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Gert Hulselmans
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Joy N Ismail
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
- UK Dementia Research Institute at Imperial College London, London, UK
| | - Koen Theunis
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Roel Vandepoel
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Valerie Christiaens
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - David Mauduit
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Stein Aerts
- Laboratory of Computational Biology, VIB Center for AI & Computational Biology (VIB.AI), Leuven, Belgium.
- VIB-KULeuven Center for Brain & Disease Research, Leuven, Belgium.
- Department of Human Genetics, KU Leuven, Leuven, Belgium.
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11
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Merrill RM, Arenas-Castro H, Feller AF, Harenčár J, Rossi M, Streisfeld MA, Kay KM. Genetics and the Evolution of Prezygotic Isolation. Cold Spring Harb Perspect Biol 2024; 16:a041439. [PMID: 37848246 PMCID: PMC10835618 DOI: 10.1101/cshperspect.a041439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
The significance of prezygotic isolation for speciation has been recognized at least since the Modern Synthesis. However, fundamental questions remain. For example, how are genetic associations between traits that contribute to prezygotic isolation maintained? What is the source of genetic variation underlying the evolution of these traits? And how do prezygotic barriers affect patterns of gene flow? We address these questions by reviewing genetic features shared across plants and animals that influence prezygotic isolation. Emerging technologies increasingly enable the identification and functional characterization of the genes involved, allowing us to test established theoretical expectations. Embedding these genes in their developmental context will allow further predictions about what constrains the evolution of prezygotic isolation. Ongoing improvements in statistical and computational tools will reveal how pre- and postzygotic isolation may differ in how they influence gene flow across the genome. Finally, we highlight opportunities for progress by combining theory with appropriate data.
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Affiliation(s)
- Richard M Merrill
- Faculty of Biology, Division of Evolutionary Biology, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Henry Arenas-Castro
- School of Biological Sciences, University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Anna F Feller
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA
- Arnold Arboretum of Harvard University, Boston, Massachusetts 02131, USA
| | - Julia Harenčár
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California 95060, USA
| | - Matteo Rossi
- Faculty of Biology, Division of Evolutionary Biology, LMU Munich, 82152 Planegg-Martinsried, Germany
| | - Matthew A Streisfeld
- Institute of Ecology and Evolution, University of Oregon, Eugene, Oregon 97403-5289, USA
| | - Kathleen M Kay
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, Santa Cruz, California 95060, USA
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12
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Salomone J, Farrow E, Gebelein B. Homeodomain complex formation and biomolecular condensates in Hox gene regulation. Semin Cell Dev Biol 2024; 152-153:93-100. [PMID: 36517343 PMCID: PMC10258226 DOI: 10.1016/j.semcdb.2022.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 10/21/2022] [Accepted: 11/30/2022] [Indexed: 12/15/2022]
Abstract
Hox genes are a family of homeodomain transcription factors that regulate specialized morphological structures along the anterior-posterior axis of metazoans. Over the past few decades, researchers have focused on defining how Hox factors with similar in vitro DNA binding activities achieve sufficient target specificity to regulate distinct cell fates in vivo. In this review, we highlight how protein interactions with other transcription factors, many of which are also homeodomain proteins, result in the formation of transcription factor complexes with enhanced DNA binding specificity. These findings suggest that Hox-regulated enhancers utilize distinct combinations of homeodomain binding sites, many of which are low-affinity, to recruit specific Hox complexes. However, low-affinity sites can only yield reproducible responses with high transcription factor concentrations. To overcome this limitation, recent studies revealed how transcription factors, including Hox factors, use intrinsically disordered domains (IDRs) to form biomolecular condensates that increase protein concentrations. Moreover, Hox factors with altered IDRs have been associated with altered transcriptional activity and human disease states, demonstrating the importance of IDRs in mediating essential Hox output. Collectively, these studies highlight how Hox factors use their DNA binding domains, protein-protein interaction domains, and IDRs to form specific transcription factor complexes that yield accurate gene expression.
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Affiliation(s)
- Joseph Salomone
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA; Medical-Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Edward Farrow
- Graduate Program in Molecular and Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA; Medical-Scientist Training Program, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, MLC 7007, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
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13
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Jindal GA, Bantle AT, Solvason JJ, Grudzien JL, D'Antonio-Chronowska A, Lim F, Le SH, Song BP, Ragsac MF, Klie A, Larsen RO, Frazer KA, Farley EK. Single-nucleotide variants within heart enhancers increase binding affinity and disrupt heart development. Dev Cell 2023; 58:2206-2216.e5. [PMID: 37848026 PMCID: PMC10720985 DOI: 10.1016/j.devcel.2023.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/07/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023]
Abstract
Transcriptional enhancers direct precise gene expression patterns during development and harbor the majority of variants associated with phenotypic diversity, evolutionary adaptations, and disease. Pinpointing which enhancer variants contribute to changes in gene expression and phenotypes is a major challenge. Here, we find that suboptimal or low-affinity binding sites are necessary for precise gene expression during heart development. Single-nucleotide variants (SNVs) can optimize the affinity of ETS binding sites, causing gain-of-function (GOF) gene expression, cell migration defects, and phenotypes as severe as extra beating hearts in the marine chordate Ciona robusta. In human induced pluripotent stem cell (iPSC)-derived cardiomyocytes, a SNV within a human GATA4 enhancer increases ETS binding affinity and causes GOF enhancer activity. The prevalence of suboptimal-affinity sites within enhancers creates a vulnerability whereby affinity-optimizing SNVs can lead to GOF gene expression, changes in cellular identity, and organismal-level phenotypes that could contribute to the evolution of novel traits or diseases.
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Affiliation(s)
- Granton A Jindal
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alexis T Bantle
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joe J Solvason
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jessica L Grudzien
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Fabian Lim
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sophia H Le
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Benjamin P Song
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michelle F Ragsac
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Adam Klie
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reid O Larsen
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kelly A Frazer
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emma K Farley
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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14
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Aguirre L, Hendelman A, Hutton SF, McCandlish DM, Lippman ZB. Idiosyncratic and dose-dependent epistasis drives variation in tomato fruit size. Science 2023; 382:315-320. [PMID: 37856609 PMCID: PMC10602613 DOI: 10.1126/science.adi5222] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 09/06/2023] [Indexed: 10/21/2023]
Abstract
Epistasis between genes is traditionally studied with mutations that eliminate protein activity, but most natural genetic variation is in cis-regulatory DNA and influences gene expression and function quantitatively. In this study, we used natural and engineered cis-regulatory alleles in a plant stem-cell circuit to systematically evaluate epistatic relationships controlling tomato fruit size. Combining a promoter allelic series with two other loci, we collected over 30,000 phenotypic data points from 46 genotypes to quantify how allele strength transforms epistasis. We revealed a saturating dose-dependent relationship but also allele-specific idiosyncratic interactions, including between alleles driving a step change in fruit size during domestication. Our approach and findings expose an underexplored dimension of epistasis, in which cis-regulatory allelic diversity within gene regulatory networks elicits nonlinear, unpredictable interactions that shape phenotypes.
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Affiliation(s)
- Lyndsey Aguirre
- Cold Spring Harbor Laboratory, School of Biological Sciences, Cold Spring Harbor, NY, USA
| | - Anat Hendelman
- Cold Spring Harbor Laboratory; Cold Spring Harbor, NY, USA
| | - Samuel F. Hutton
- Gulf Coast Research and Education Center, University of Florida, Wimauma, FL, USA
| | | | - Zachary B. Lippman
- Cold Spring Harbor Laboratory, School of Biological Sciences, Cold Spring Harbor, NY, USA
- Cold Spring Harbor Laboratory; Cold Spring Harbor, NY, USA
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
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15
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Dardiry M, Eberhard G, Witte H, Rödelsperger C, Lightfoot JW, Sommer RJ. Divergent combinations of cis-regulatory elements control the evolution of phenotypic plasticity. PLoS Biol 2023; 21:e3002270. [PMID: 37590316 PMCID: PMC10464979 DOI: 10.1371/journal.pbio.3002270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 08/29/2023] [Accepted: 07/22/2023] [Indexed: 08/19/2023] Open
Abstract
The widespread occurrence of phenotypic plasticity across all domains of life demonstrates its evolutionary significance. However, how plasticity itself evolves and how it contributes to evolution is poorly understood. Here, we investigate the predatory nematode Pristionchus pacificus with its feeding structure plasticity using recombinant-inbred-line and quantitative-trait-locus (QTL) analyses between natural isolates. We show that a single QTL at a core developmental gene controls the expression of the cannibalistic morph. This QTL is composed of several cis-regulatory elements. Through CRISPR/Cas-9 engineering, we identify copy number variation of potential transcription factor binding sites that interacts with a single intronic nucleotide polymorphism. Another intronic element eliminates gene expression altogether, mimicking knockouts of the locus. Comparisons of additional isolates further support the rapid evolution of these cis-regulatory elements. Finally, an independent QTL study reveals evidence for parallel evolution at the same locus. Thus, combinations of cis-regulatory elements shape plastic trait expression and control nematode cannibalism.
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Affiliation(s)
- Mohannad Dardiry
- Max-Planck Institute for Biology Tübingen, Tübingen, Germany
- Department of Genetics, Faculty of Agriculture, Cairo University, Giza, Egypt
| | - Gabi Eberhard
- Max-Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Hanh Witte
- Max-Planck Institute for Biology Tübingen, Tübingen, Germany
| | | | - James W. Lightfoot
- Max-Planck Institute for Biology Tübingen, Tübingen, Germany
- Max Planck Research Group Genetics of Behavior, Max Planck Institute for Neurobiology of Behavior–caesar, Bonn, Germany
| | - Ralf J. Sommer
- Max-Planck Institute for Biology Tübingen, Tübingen, Germany
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16
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Li XC, Fuqua T, van Breugel ME, Crocker J. Mutational scans reveal differential evolvability of Drosophila promoters and enhancers. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220054. [PMID: 37004721 PMCID: PMC10067265 DOI: 10.1098/rstb.2022.0054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023] Open
Abstract
Rapid enhancer and slow promoter evolution have been demonstrated through comparative genomics. However, it is not clear how this information is encoded genetically and if this can be used to place evolution in a predictive context. Part of the challenge is that our understanding of the potential for regulatory evolution is biased primarily toward natural variation or limited experimental perturbations. Here, to explore the evolutionary capacity of promoter variation, we surveyed an unbiased mutation library for three promoters in Drosophila melanogaster. We found that mutations in promoters had limited to no effect on spatial patterns of gene expression. Compared to developmental enhancers, promoters are more robust to mutations and have more access to mutations that can increase gene expression, suggesting that their low activity might be a result of selection. Consistent with these observations, increasing the promoter activity at the endogenous locus of shavenbaby led to increased transcription yet limited phenotypic changes. Taken together, developmental promoters may encode robust transcriptional outputs allowing evolvability through the integration of diverse developmental enhancers. This article is part of the theme issue ‘Interdisciplinary approaches to predicting evolutionary biology’.
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Affiliation(s)
- Xueying C. Li
- European Molecular Biology Laboratory, Heidelberg, Baden-Württemberg 69117, Germany
| | - Timothy Fuqua
- European Molecular Biology Laboratory, Heidelberg, Baden-Württemberg 69117, Germany
| | | | - Justin Crocker
- European Molecular Biology Laboratory, Heidelberg, Baden-Württemberg 69117, Germany
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17
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Murugesan SN, Monteiro A. Evolution of modular and pleiotropic enhancers. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:105-115. [PMID: 35334158 DOI: 10.1002/jez.b.23131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 01/14/2022] [Accepted: 02/28/2022] [Indexed: 11/05/2022]
Abstract
Cis-regulatory elements (CREs), or enhancers, are segments of noncoding DNA that regulate the spatial and temporal expression of nearby genes. Sometimes, genes are expressed in more than one tissue, and this can be driven by two main types of CREs: tissue-specific "modular" CREs, where different CREs drive expression of the gene in the different tissues, or by "pleiotropic" CREs, where the same CRE drives expression in the different tissues. In this perspective, we will discuss some of the ways (i) modular and pleiotropic CREs might originate; (ii) propose that modular CREs might derive from pleiotropic CREs via a process of duplication, degeneration, and complementation (the CRE-DDC model); and (iii) propose that hotspot loci of evolution are associated with the origin of modular CREs belonging to any gene in a regulatory network.
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Affiliation(s)
- Suriya N Murugesan
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Antónia Monteiro
- Department of Biological Sciences, National University of Singapore, Singapore.,Division of Science, Yale-NUS College, Singapore
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18
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Feigin C, Li S, Moreno J, Mallarino R. The GRN concept as a guide for evolutionary developmental biology. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:92-104. [PMID: 35344632 PMCID: PMC9515236 DOI: 10.1002/jez.b.23132] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 03/08/2022] [Accepted: 03/11/2022] [Indexed: 12/13/2022]
Abstract
Organismal phenotypes result largely from inherited developmental programs, usually executed during embryonic and juvenile life stages. These programs are not blank slates onto which natural selection can draw arbitrary forms. Rather, the mechanisms of development play an integral role in shaping phenotypic diversity and help determine the evolutionary trajectories of species. Modern evolutionary biology must, therefore, account for these mechanisms in both theory and in practice. The gene regulatory network (GRN) concept represents a potent tool for achieving this goal whose utility has grown in tandem with advances in "omic" technologies and experimental techniques. However, while the GRN concept is widely utilized, it is often less clear what practical implications it has for conducting research in evolutionary developmental biology. In this Perspective, we attempt to provide clarity by discussing how experiments and projects can be designed in light of the GRN concept. We first map familiar biological notions onto the more abstract components of GRN models. We then review how diverse functional genomic approaches can be directed toward the goal of constructing such models and discuss current methods for functionally testing evolutionary hypotheses that arise from them. Finally, we show how the major steps of GRN model construction and experimental validation suggest generalizable workflows that can serve as a scaffold for project design. Taken together, the practical implications that we draw from the GRN concept provide a set of guideposts for studies aiming at unraveling the molecular basis of phenotypic diversity.
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Affiliation(s)
- Charles Feigin
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA,School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Sha Li
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Jorge Moreno
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - Ricardo Mallarino
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
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19
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Reiter F, de Almeida BP, Stark A. Enhancers display constrained sequence flexibility and context-specific modulation of motif function. Genome Res 2023; 33:346-358. [PMID: 36941077 PMCID: PMC10078294 DOI: 10.1101/gr.277246.122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/14/2023] [Indexed: 03/23/2023]
Abstract
The information about when and where each gene is to be expressed is mainly encoded in the DNA sequence of enhancers, sequence elements that comprise binding sites (motifs) for different transcription factors (TFs). Most of the research on enhancer sequences has been focused on TF motif presence, whereas the enhancer syntax, that is, the flexibility of important motif positions and how the sequence context modulates the activity of TF motifs, remains poorly understood. Here, we explore the rules of enhancer syntax by a two-pronged approach in Drosophila melanogaster S2 cells: we (1) replace important TF motifs by all possible 65,536 eight-nucleotide-long sequences and (2) paste eight important TF motif types into 763 positions within 496 enhancers. These complementary strategies reveal that enhancers display constrained sequence flexibility and the context-specific modulation of motif function. Important motifs can be functionally replaced by hundreds of sequences constituting several distinct motif types, but these are only a fraction of all possible sequences and motif types. Moreover, TF motifs contribute with different intrinsic strengths that are strongly modulated by the enhancer sequence context (the flanking sequence, the presence and diversity of other motif types, and the distance between motifs), such that not all motif types can work in all positions. The context-specific modulation of motif function is also a hallmark of human enhancers, as we demonstrate experimentally. Overall, these two general principles of enhancer sequences are important to understand and predict enhancer function during development, evolution, and in disease.
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Affiliation(s)
- Franziska Reiter
- Research Institute of Molecular Pathology, Vienna BioCenter, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Bernardo P de Almeida
- Research Institute of Molecular Pathology, Vienna BioCenter, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology, Vienna BioCenter, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria;
- Medical University of Vienna, Vienna BioCenter, 1030 Vienna, Austria
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20
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Song BP, Ragsac MF, Tellez K, Jindal GA, Grudzien JL, Le SH, Farley EK. Diverse logics and grammar encode notochord enhancers. Cell Rep 2023; 42:112052. [PMID: 36729834 PMCID: PMC10387507 DOI: 10.1016/j.celrep.2023.112052] [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: 07/29/2022] [Revised: 11/07/2022] [Accepted: 01/17/2023] [Indexed: 02/03/2023] Open
Abstract
The notochord is a defining feature of all chordates. The transcription factors Zic and ETS regulate enhancer activity within the notochord. We conduct high-throughput screens of genomic elements within developing Ciona embryos to understand how Zic and ETS sites encode notochord activity. Our screen discovers an enhancer located near Lama, a gene critical for notochord development. Reversing the orientation of an ETS site within this enhancer abolishes expression, indicating that enhancer grammar is critical for notochord activity. Similarly organized clusters of Zic and ETS sites occur within mouse and human Lama1 introns. Within a Brachyury (Bra) enhancer, FoxA and Bra, in combination with Zic and ETS binding sites, are necessary and sufficient for notochord expression. This binding site logic also occurs within other Ciona and vertebrate Bra enhancers. Collectively, this study uncovers the importance of grammar within notochord enhancers and discovers signatures of enhancer logic and grammar conserved across chordates.
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Affiliation(s)
- Benjamin P Song
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093, USA
| | - Michelle F Ragsac
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA 92093, USA
| | - Krissie Tellez
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Granton A Jindal
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jessica L Grudzien
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Sophia H Le
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Emma K Farley
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA.
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21
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Kim S, Wysocka J. Deciphering the multi-scale, quantitative cis-regulatory code. Mol Cell 2023; 83:373-392. [PMID: 36693380 PMCID: PMC9898153 DOI: 10.1016/j.molcel.2022.12.032] [Citation(s) in RCA: 69] [Impact Index Per Article: 69.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/24/2023]
Abstract
Uncovering the cis-regulatory code that governs when and how much each gene is transcribed in a given genome and cellular state remains a central goal of biology. Here, we discuss major layers of regulation that influence how transcriptional outputs are encoded by DNA sequence and cellular context. We first discuss how transcription factors bind specific DNA sequences in a dosage-dependent and cooperative manner and then proceed to the cofactors that facilitate transcription factor function and mediate the activity of modular cis-regulatory elements such as enhancers, silencers, and promoters. We then consider the complex and poorly understood interplay of these diverse elements within regulatory landscapes and its relationships with chromatin states and nuclear organization. We propose that a mechanistically informed, quantitative model of transcriptional regulation that integrates these multiple regulatory layers will be the key to ultimately cracking the cis-regulatory code.
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Affiliation(s)
- Seungsoo Kim
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; 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
| | - Joanna Wysocka
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; 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.
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22
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Galupa R, Alvarez-Canales G, Borst NO, Fuqua T, Gandara L, Misunou N, Richter K, Alves MRP, Karumbi E, Perkins ML, Kocijan T, Rushlow CA, Crocker J. Enhancer architecture and chromatin accessibility constrain phenotypic space during Drosophila development. Dev Cell 2023; 58:51-62.e4. [PMID: 36626871 PMCID: PMC9860173 DOI: 10.1016/j.devcel.2022.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/18/2022] [Accepted: 12/07/2022] [Indexed: 01/11/2023]
Abstract
Developmental enhancers bind transcription factors and dictate patterns of gene expression during development. Their molecular evolution can underlie phenotypical evolution, but the contributions of the evolutionary pathways involved remain little understood. Here, using mutation libraries in Drosophila melanogaster embryos, we observed that most point mutations in developmental enhancers led to changes in gene expression levels but rarely resulted in novel expression outside of the native pattern. In contrast, random sequences, often acting as developmental enhancers, drove expression across a range of cell types; random sequences including motifs for transcription factors with pioneer activity acted as enhancers even more frequently. Our findings suggest that the phenotypic landscapes of developmental enhancers are constrained by enhancer architecture and chromatin accessibility. We propose that the evolution of existing enhancers is limited in its capacity to generate novel phenotypes, whereas the activity of de novo elements is a primary source of phenotypic novelty.
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Affiliation(s)
- Rafael Galupa
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | | | | | - Timothy Fuqua
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Lautaro Gandara
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Natalia Misunou
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Kerstin Richter
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Esther Karumbi
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Tin Kocijan
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Justin Crocker
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
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23
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Draghi JA, Ogbunugafor CB. Exploring the expanse between theoretical questions and experimental approaches in the modern study of evolvability. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:8-17. [PMID: 35451559 PMCID: PMC10083935 DOI: 10.1002/jez.b.23134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/04/2022] [Accepted: 03/11/2022] [Indexed: 12/16/2022]
Abstract
Despite several decades of computational and experimental work across many systems, evolvability remains on the periphery with regards to its status as a widely accepted and regularly applied theoretical concept. Here we propose that its marginal status is partly a result of large gaps between the diverse but disconnected theoretical treatments of evolvability and the relatively narrower range of studies that have tested it empirically. To make this case, we draw on a range of examples-from experimental evolution in microbes, to molecular evolution in proteins-where attempts have been made to mend this disconnect. We highlight some examples of progress that has been made and point to areas where synthesis and translation of existing theory can lead to further progress in the still-new field of empirical measurements of evolvability.
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Affiliation(s)
- Jeremy A Draghi
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, USA
| | - C Brandon Ogbunugafor
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, Connecticut, USA
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24
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Developmental phenomics suggests that H3K4 monomethylation confers multi-level phenotypic robustness. Cell Rep 2022; 41:111832. [PMID: 36516782 PMCID: PMC9764455 DOI: 10.1016/j.celrep.2022.111832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/29/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022] Open
Abstract
How histone modifications affect animal development remains difficult to ascertain. Despite the prevalence of histone 3 lysine 4 monomethylation (H3K4me1) on enhancers, hypomethylation appears to have minor effects on phenotype and viability. Here, we genetically reduce H3K4me1 deposition in Drosophila melanogaster and find that hypomethylation reduces transcription factor enrichment in nuclear microenvironments, disrupts gene expression, and reduces phenotypic robustness. Using a developmental phenomics approach, we find changes in morphology, metabolism, behavior, and offspring production. However, many phenotypic changes are only detected when hypomethylated flies develop outside of standard laboratory environments or with specific genetic backgrounds. Therefore, quantitative phenomics measurements can unravel how pleiotropic modulators of gene expression affect developmental robustness under conditions resembling the natural environments of a species.
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25
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Mangan RJ, Alsina FC, Mosti F, Sotelo-Fonseca JE, Snellings DA, Au EH, Carvalho J, Sathyan L, Johnson GD, Reddy TE, Silver DL, Lowe CB. Adaptive sequence divergence forged new neurodevelopmental enhancers in humans. Cell 2022; 185:4587-4603.e23. [PMID: 36423581 PMCID: PMC10013929 DOI: 10.1016/j.cell.2022.10.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 09/08/2022] [Accepted: 10/14/2022] [Indexed: 11/24/2022]
Abstract
Searches for the genetic underpinnings of uniquely human traits have focused on human-specific divergence in conserved genomic regions, which reflects adaptive modifications of existing functional elements. However, the study of conserved regions excludes functional elements that descended from previously neutral regions. Here, we demonstrate that the fastest-evolved regions of the human genome, which we term "human ancestor quickly evolved regions" (HAQERs), rapidly diverged in an episodic burst of directional positive selection prior to the human-Neanderthal split, before transitioning to constraint within hominins. HAQERs are enriched for bivalent chromatin states, particularly in gastrointestinal and neurodevelopmental tissues, and genetic variants linked to neurodevelopmental disease. We developed a multiplex, single-cell in vivo enhancer assay to discover that rapid sequence divergence in HAQERs generated hominin-unique enhancers in the developing cerebral cortex. We propose that a lack of pleiotropic constraints and elevated mutation rates poised HAQERs for rapid adaptation and subsequent susceptibility to disease.
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Affiliation(s)
- Riley J Mangan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Fernando C Alsina
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Federica Mosti
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Daniel A Snellings
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Eric H Au
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Juliana Carvalho
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Laya Sathyan
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Graham D Johnson
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27705, USA; Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27710, USA
| | - Timothy E Reddy
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27705, USA; Department of Biostatistics and Bioinformatics, Duke University Medical Center, Durham, NC 27710, USA
| | - Debra L Silver
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Duke Institute for Brain Sciences and Duke Regeneration Center, Duke University Medical Center, Durham, NC 27710, USA; Departments of Cell Biology and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Craig B Lowe
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27705, USA.
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26
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Accumulation and maintenance of information in evolution. Proc Natl Acad Sci U S A 2022; 119:e2123152119. [PMID: 36037343 PMCID: PMC9457054 DOI: 10.1073/pnas.2123152119] [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] [Indexed: 11/18/2022] Open
Abstract
Selection accumulates information in the genome-it guides stochastically evolving populations toward states (genotype frequencies) that would be unlikely under neutrality. This can be quantified as the Kullback-Leibler (KL) divergence between the actual distribution of genotype frequencies and the corresponding neutral distribution. First, we show that this population-level information sets an upper bound on the information at the level of genotype and phenotype, limiting how precisely they can be specified by selection. Next, we study how the accumulation and maintenance of information is limited by the cost of selection, measured as the genetic load or the relative fitness variance, both of which we connect to the control-theoretic KL cost of control. The information accumulation rate is upper bounded by the population size times the cost of selection. This bound is very general, and applies across models (Wright-Fisher, Moran, diffusion) and to arbitrary forms of selection, mutation, and recombination. Finally, the cost of maintaining information depends on how it is encoded: Specifying a single allele out of two is expensive, but one bit encoded among many weakly specified loci (as in a polygenic trait) is cheap.
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27
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Abstract
When Mendel's work was rediscovered in 1900, and extended to establish classical genetics, it was initially seen in opposition to Darwin's theory of evolution by natural selection on continuous variation, as represented by the biometric research program that was the foundation of quantitative genetics. As Fisher, Haldane, and Wright established a century ago, Mendelian inheritance is exactly what is needed for natural selection to work efficiently. Yet, the synthesis remains unfinished. We do not understand why sexual reproduction and a fair meiosis predominate in eukaryotes, or how far these are responsible for their diversity and complexity. Moreover, although quantitative geneticists have long known that adaptive variation is highly polygenic, and that this is essential for efficient selection, this is only now becoming appreciated by molecular biologists-and we still do not have a good framework for understanding polygenic variation or diffuse function.
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Affiliation(s)
- Nicholas H. Barton
- Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria
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28
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Different transcriptional responses by the CRISPRa system in distinct types of heterochromatin in Drosophila melanogaster. Sci Rep 2022; 12:11702. [PMID: 35810197 PMCID: PMC9271074 DOI: 10.1038/s41598-022-15944-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/01/2022] [Indexed: 11/09/2022] Open
Abstract
Transcription factors (TFs) activate gene expression by binding to elements close to promoters or enhancers. Some TFs can bind to heterochromatic regions to initiate gene activation, suggesting that if a TF is able to bind to any type of heterochromatin, it can activate transcription. To investigate this possibility, we used the CRISPRa system based on dCas9-VPR as an artificial TF in Drosophila. dCas9-VPR was targeted to the TAHRE telomeric element, an example of constitutive heterochromatin, and to promoters and enhancers of the HOX Ultrabithorax (Ubx) and Sex Combs Reduced (Scr) genes in the context of facultative heterochromatin. dCas9-VPR robustly activated TAHRE transcription, showing that although this element is heterochromatic, dCas9-VPR was sufficient to activate its expression. In the case of HOX gene promoters, although Polycomb complexes epigenetically silence these genes, both were ectopically activated. When the artificial TF was directed to enhancers, we found that the expression pattern was different compared to the effect on the promoters. In the case of the Scr upstream enhancer, dCas9-VPR activated the gene ectopically but with less expressivity; however, ectopic activation also occurred in different cells. In the case of the bxI enhancer located in the third intron of Ubx, the presence of dCas9-VPR is capable of increasing transcription initiation while simultaneously blocking transcription elongation, generating a lack of functional phenotype. Our results show that CRISPRa system is able to activate transcription in any type of heterochromatin; nevertheless, its effect on transcription is subject to the intrinsic characteristics of each gene or regulatory element.
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29
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Laiker I, Frankel N. Pleiotropic Enhancers are Ubiquitous Regulatory Elements in the Human Genome. Genome Biol Evol 2022; 14:evac071. [PMID: 35552697 PMCID: PMC9156028 DOI: 10.1093/gbe/evac071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Enhancers are regulatory elements of genomes that determine spatio-temporal patterns of gene expression. The human genome contains a vast number of enhancers, which largely outnumber protein-coding genes. Historically, enhancers have been regarded as highly tissue-specific. However, recent evidence has demonstrated that many enhancers are pleiotropic, with activity in multiple developmental contexts. Yet, the extent and impact of pleiotropy remain largely unexplored. In this study we analyzed active enhancers across human organs based on the analysis of both eRNA transcription (FANTOM5 consortium data sets) and chromatin architecture (ENCODE consortium data sets). We show that pleiotropic enhancers are pervasive in the human genome and that most enhancers active in a particular organ are also active in other organs. In addition, our analysis suggests that the proportion of context-specific enhancers of a given organ is explained, at least in part, by the proportion of context-specific genes in that same organ. The notion that such a high proportion of human enhancers can be pleiotropic suggests that small regions of regulatory DNA contain abundant regulatory information and that these regions evolve under important evolutionary constraints.
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Affiliation(s)
- Ian Laiker
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad de Buenos Aires (UBA), Buenos Aires 1428, Argentina
| | - Nicolás Frankel
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Universidad de Buenos Aires (UBA), Buenos Aires 1428, Argentina
- Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA), Buenos Aires 1428, Argentina
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30
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Perkins ML, Gandara L, Crocker J. A synthetic synthesis to explore animal evolution and development. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200517. [PMID: 35634925 PMCID: PMC9149795 DOI: 10.1098/rstb.2020.0517] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Identifying the general principles by which genotypes are converted into phenotypes remains a challenge in the post-genomic era. We still lack a predictive understanding of how genes shape interactions among cells and tissues in response to signalling and environmental cues, and hence how regulatory networks generate the phenotypic variation required for adaptive evolution. Here, we discuss how techniques borrowed from synthetic biology may facilitate a systematic exploration of evolvability across biological scales. Synthetic approaches permit controlled manipulation of both endogenous and fully engineered systems, providing a flexible platform for investigating causal mechanisms in vivo. Combining synthetic approaches with multi-level phenotyping (phenomics) will supply a detailed, quantitative characterization of how internal and external stimuli shape the morphology and behaviour of living organisms. We advocate integrating high-throughput experimental data with mathematical and computational techniques from a variety of disciplines in order to pursue a comprehensive theory of evolution. This article is part of the theme issue ‘Genetic basis of adaptation and speciation: from loci to causative mutations’.
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Affiliation(s)
- Mindy Liu Perkins
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Lautaro Gandara
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Justin Crocker
- Developmental Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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31
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Fernandes G, Tran H, Andrieu M, Diaw Y, Perez Romero C, Fradin C, Coppey M, Walczak AM, Dostatni N. Synthetic reconstruction of the hunchback promoter specifies the role of Bicoid, Zelda and Hunchback in the dynamics of its transcription. eLife 2022; 11:74509. [PMID: 35363606 PMCID: PMC8975551 DOI: 10.7554/elife.74509] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 03/10/2022] [Indexed: 11/23/2022] Open
Abstract
For over 40 years, the Bicoid-hunchback (Bcd-hb) system in the fruit fly embryo has been used as a model to study how positional information in morphogen concentration gradients is robustly translated into step-like responses. A body of quantitative comparisons between theory and experiment have since questioned the initial paradigm that the sharp hb transcription pattern emerges solely from diffusive biochemical interactions between the Bicoid transcription factor and the gene promoter region. Several alternative mechanisms have been proposed, such as additional sources of positional information, positive feedback from Hb proteins or out-of-equilibrium transcription activation. By using the MS2-MCP RNA-tagging system and analysing in real time, the transcription dynamics of synthetic reporters for Bicoid and/or its two partners Zelda and Hunchback, we show that all the early hb expression pattern features and temporal dynamics are compatible with an equilibrium model with a short decay length Bicoid activity gradient as a sole source of positional information. Meanwhile, Bicoid’s partners speed-up the process by different means: Zelda lowers the Bicoid concentration threshold required for transcriptional activation while Hunchback reduces burstiness and increases the polymerase firing rate.
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Affiliation(s)
- Gonçalo Fernandes
- Institut Curie, Université PSL, Sorbonne Université, CNRS, Nuclear Dynamics, Paris, France
| | - Huy Tran
- Institut Curie, Université PSL, Sorbonne Université, CNRS, Nuclear Dynamics, Paris, France.,Laboratoire de Physique de l'École Normale Supérieure, CNRS, Université PSL, Sorbonne Université and Université de Paris, Paris, France
| | - Maxime Andrieu
- Institut Curie, Université PSL, Sorbonne Université, CNRS, Nuclear Dynamics, Paris, France
| | - Youssoupha Diaw
- Institut Curie, Université PSL, Sorbonne Université, CNRS, Nuclear Dynamics, Paris, France
| | - Carmina Perez Romero
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Cécile Fradin
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.,Department of Physics and Astronomy, McMaster University, Hamilton, Canada
| | - Mathieu Coppey
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico Chimie Curie, Paris, France
| | - Aleksandra M Walczak
- Laboratoire de Physique de l'École Normale Supérieure, CNRS, Université PSL, Sorbonne Université and Université de Paris, Paris, France
| | - Nathalie Dostatni
- Institut Curie, Université PSL, Sorbonne Université, CNRS, Nuclear Dynamics, Paris, France
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32
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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: 50] [Impact Index Per Article: 25.0] [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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33
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The evolution, evolvability and engineering of gene regulatory DNA. Nature 2022; 603:455-463. [PMID: 35264797 DOI: 10.1038/s41586-022-04506-6] [Citation(s) in RCA: 92] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 02/02/2022] [Indexed: 11/08/2022]
Abstract
Mutations in non-coding regulatory DNA sequences can alter gene expression, organismal phenotype and fitness1-3. Constructing complete fitness landscapes, in which DNA sequences are mapped to fitness, is a long-standing goal in biology, but has remained elusive because it is challenging to generalize reliably to vast sequence spaces4-6. Here we build sequence-to-expression models that capture fitness landscapes and use them to decipher principles of regulatory evolution. Using millions of randomly sampled promoter DNA sequences and their measured expression levels in the yeast Saccharomyces cerevisiae, we learn deep neural network models that generalize with excellent prediction performance, and enable sequence design for expression engineering. Using our models, we study expression divergence under genetic drift and strong-selection weak-mutation regimes to find that regulatory evolution is rapid and subject to diminishing returns epistasis; that conflicting expression objectives in different environments constrain expression adaptation; and that stabilizing selection on gene expression leads to the moderation of regulatory complexity. We present an approach for using such models to detect signatures of selection on expression from natural variation in regulatory sequences and use it to discover an instance of convergent regulatory evolution. We assess mutational robustness, finding that regulatory mutation effect sizes follow a power law, characterize regulatory evolvability, visualize promoter fitness landscapes, discover evolvability archetypes and illustrate the mutational robustness of natural regulatory sequence populations. Our work provides a general framework for designing regulatory sequences and addressing fundamental questions in regulatory evolution.
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34
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Transcriptional Regulation and Implications for Controlling Hox Gene Expression. J Dev Biol 2022; 10:jdb10010004. [PMID: 35076545 PMCID: PMC8788451 DOI: 10.3390/jdb10010004] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/04/2022] [Accepted: 01/06/2022] [Indexed: 02/06/2023] Open
Abstract
Hox genes play key roles in axial patterning and regulating the regional identity of cells and tissues in a wide variety of animals from invertebrates to vertebrates. Nested domains of Hox expression generate a combinatorial code that provides a molecular framework for specifying the properties of tissues along the A–P axis. Hence, it is important to understand the regulatory mechanisms that coordinately control the precise patterns of the transcription of clustered Hox genes required for their roles in development. New insights are emerging about the dynamics and molecular mechanisms governing transcriptional regulation, and there is interest in understanding how these may play a role in contributing to the regulation of the expression of the clustered Hox genes. In this review, we summarize some of the recent findings, ideas and emerging mechanisms underlying the regulation of transcription in general and consider how they may be relevant to understanding the transcriptional regulation of Hox genes.
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35
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Waters CT, Gisselbrecht SS, Sytnikova YA, Cafarelli TM, Hill DE, Bulyk ML. Quantitative-enhancer-FACS-seq (QeFS) reveals epistatic interactions among motifs within transcriptional enhancers in developing Drosophila tissue. Genome Biol 2021; 22:348. [PMID: 34930411 PMCID: PMC8686523 DOI: 10.1186/s13059-021-02574-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Understanding the contributions of transcription factor DNA binding sites to transcriptional enhancers is a significant challenge. We developed Quantitative enhancer-FACS-Seq for highly parallel quantification of enhancer activities from a genomically integrated reporter in Drosophila melanogaster embryos. We investigate the contributions of the DNA binding motifs of four poorly characterized TFs to the activities of twelve embryonic mesodermal enhancers. We measure quantitative changes in enhancer activity and discover a range of epistatic interactions among the motifs, both synergistic and alleviating. We find that understanding the regulatory consequences of TF binding motifs requires that they be investigated in combination across enhancer contexts.
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Affiliation(s)
- Colin T Waters
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
- Program in Biological and Biomedical Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Stephen S Gisselbrecht
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Yuliya A Sytnikova
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA
| | - Tiziana M Cafarelli
- Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - David E Hill
- Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Martha L Bulyk
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
- Program in Biological and Biomedical Sciences, Harvard University, Cambridge, MA, 02138, USA.
- Center for Cancer Systems Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, 02115, USA.
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36
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Parker HJ, De Kumar B, Pushel I, Bronner ME, Krumlauf R. Analysis of lamprey meis genes reveals that conserved inputs from Hox, Meis and Pbx proteins control their expression in the hindbrain and neural tube. Dev Biol 2021; 479:61-76. [PMID: 34310923 DOI: 10.1016/j.ydbio.2021.07.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/10/2021] [Accepted: 07/22/2021] [Indexed: 11/23/2022]
Abstract
Meis genes are known to play important roles in the hindbrain and neural crest cells of jawed vertebrates. To explore the roles of Meis genes in head development during evolution of vertebrates, we have identified four meis genes in the sea lamprey genome and characterized their patterns of expression and regulation, with a focus on the hindbrain and pharynx. Each of the lamprey meis genes displays temporally and spatially dynamic patterns of expression, some of which are coupled to rhombomeric domains in the developing hindbrain and select pharyngeal arches. Studies of Meis loci in mouse and zebrafish have identified enhancers that are bound by Hox and TALE (Meis and Pbx) proteins, implicating these factors in the direct regulation of Meis expression. We examined the lamprey meis loci and identified a series of cis-elements conserved between lamprey and jawed vertebrate meis genes. In transgenic reporter assays we demonstrated that these elements act as neural enhancers in lamprey embryos, directing reporter expression in appropriate domains when compared to expression of their associated endogenous meis gene. Sequence alignments reveal that these conserved elements are in similar relative positions of the meis loci and contain a series of consensus binding motifs for Hox and TALE proteins. This suggests that ancient Hox and TALE-responsive enhancers regulated expression of ancestral vertebrate meis genes in segmental domains in the hindbrain and have been retained in the meis loci during vertebrate evolution. The presence of conserved Meis, Pbx and Hox binding sites in these lamprey enhancers links Hox and TALE factors to regulation of lamprey meis genes in the developing hindbrain, indicating a deep ancestry for these regulatory interactions prior to the divergence of jawed and jawless vertebrates.
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Affiliation(s)
- Hugo J Parker
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Bony De Kumar
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Irina Pushel
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, 64110, USA; Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS, 66160, USA.
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37
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Oda-Ishii I, Yu D, Satou Y. Two distinct motifs for Zic-r.a drive specific gene expression in two cell lineages. Development 2021; 148:269043. [PMID: 34100063 DOI: 10.1242/dev.199538] [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] [Received: 02/16/2021] [Accepted: 04/26/2021] [Indexed: 11/20/2022]
Abstract
Zic-r.a, a maternal transcription factor, specifies posterior fate in ascidian embryos. However, its direct target, Tbx6-r.b, does not contain typical Zic-r.a-binding sites in its regulatory region. Using an in vitro selection assay, we found that Zic-r.a binds to sites dissimilar to the canonical motif, by which it activates Tbx6-r.b in a sub-lineage of muscle cells. These sites with non-canonical motifs have weak affinity for Zic-r.a; therefore, it activates Tbx6-r.b only in cells expressing Zic-r.a abundantly. Meanwhile, we found that Zic-r.a expressed zygotically in late embryos activates neural genes through canonical sites. Because different zinc-finger domains of Zic-r.a are important for driving reporters with canonical and non-canonical sites, it is likely that the non-canonical motif is not a divergent version of the canonical motif. In other words, our data indicate that the non-canonical motif represents a motif distinct from the canonical motif. Thus, Zic-r.a recognizes two distinct motifs to activate two sets of genes at two timepoints in development. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Izumi Oda-Ishii
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Deli Yu
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yutaka Satou
- Department of Zoology, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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38
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Fuqua T, Jordan J, Halavatyi A, Tischer C, Richter K, Crocker J. An open-source semi-automated robotics pipeline for embryo immunohistochemistry. Sci Rep 2021; 11:10314. [PMID: 33986394 PMCID: PMC8119710 DOI: 10.1038/s41598-021-89676-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/19/2021] [Indexed: 11/09/2022] Open
Abstract
A significant challenge for developmental systems biology is balancing throughput with controlled conditions that minimize experimental artifacts. Large-scale developmental screens such as unbiased mutagenesis surveys have been limited in their applicability to embryonic systems, as the technologies for quantifying precise expression patterns in whole animals has not kept pace with other sequencing-based technologies. Here, we outline an open-source semi-automated pipeline to chemically fixate, stain, and 3D-image Drosophila embryos. Central to this pipeline is a liquid handling robot, Flyspresso, which automates the steps of classical embryo fixation and staining. We provide the schematics and an overview of the technology for an engineer or someone equivalently trained to reproduce and further improve upon Flyspresso, and highlight the Drosophila embryo fixation and colorimetric or antibody staining protocols. Additionally, we provide a detailed overview and stepwise protocol for our adaptive-feedback pipeline for automated embryo imaging on confocal microscopes. We demonstrate the efficiency of this pipeline compared to classical techniques, and how it can be repurposed or scaled to other protocols and biological systems. We hope our pipeline will serve as a platform for future research, allowing a broader community of users to build, execute, and share similar experiments.
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Affiliation(s)
- Timothy Fuqua
- European Molecular Biology Laboratory, Heidelberg, Germany.,Collaboration for Joint PhD Degree Between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Jeff Jordan
- Janelia Research Campus, 19700 Helix Dr, Ashburn, VA, 20147, USA
| | | | | | | | - Justin Crocker
- European Molecular Biology Laboratory, Heidelberg, Germany.
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39
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Froehlich JJ, Uyar B, Herzog M, Theil K, Glažar P, Akalin A, Rajewsky N. Parallel genetics of regulatory sequences using scalable genome editing in vivo. Cell Rep 2021; 35:108988. [PMID: 33852857 DOI: 10.1016/j.celrep.2021.108988] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 01/13/2021] [Accepted: 03/23/2021] [Indexed: 12/27/2022] Open
Abstract
How regulatory sequences control gene expression is fundamental for explaining phenotypes in health and disease. Regulatory elements must ultimately be understood within their genomic environment and development- or tissue-specific contexts. Because this is technically challenging, few regulatory elements have been characterized in vivo. Here, we use inducible Cas9 and multiplexed guide RNAs to create hundreds of mutations in enhancers/promoters and 3' UTRs of 16 genes in C. elegans. Our software crispr-DART analyzes indel mutations in targeted DNA sequencing. We quantify the impact of mutations on expression and fitness by targeted RNA sequencing and DNA sampling. When applying our approach to the lin-41 3' UTR, generating hundreds of mutants, we find that the two adjacent binding sites for the miRNA let-7 can regulate lin-41 expression independently of each other. Finally, we map regulatory genotypes to phenotypic traits for several genes. Our approach enables parallel analysis of regulatory sequences directly in animals.
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Affiliation(s)
- Jonathan J Froehlich
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany
| | - Bora Uyar
- Bioinformatics and Omics Data Science Platform, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany
| | - Margareta Herzog
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany
| | - Kathrin Theil
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany
| | - Petar Glažar
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany
| | - Altuna Akalin
- Bioinformatics and Omics Data Science Platform, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany
| | - Nikolaus Rajewsky
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Hannoversche Str. 28, 10115 Berlin, Germany.
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40
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Wang X, Aguirre L, Rodríguez-Leal D, Hendelman A, Benoit M, Lippman ZB. Dissecting cis-regulatory control of quantitative trait variation in a plant stem cell circuit. NATURE PLANTS 2021; 7:419-427. [PMID: 33846596 DOI: 10.1038/s41477-021-00898-x] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/10/2021] [Indexed: 05/22/2023]
Abstract
Cis-regulatory mutations underlie important crop domestication and improvement traits1,2. However, limited allelic diversity has hindered functional dissection of the large number of cis-regulatory elements and their potential interactions, thereby precluding a deeper understanding of how cis-regulatory variation impacts traits quantitatively. Here, we engineered over 60 promoter alleles in two tomato fruit size genes3,4 to characterize cis-regulatory sequences and study their functional relationships. We found that targeted mutations in conserved promoter sequences of SlCLV3, a repressor of stem cell proliferation5,6, have a weak impact on fruit locule number. Pairwise combinations of these mutations mildly enhance this phenotype, revealing additive and synergistic relationships between conserved regions and further suggesting even higher-order cis-regulatory interactions within the SlCLV3 promoter. In contrast, SlWUS, a positive regulator of stem cell proliferation repressed by SlCLV3 (refs. 5,6), is more tolerant to promoter perturbations. Our results show that complex interplay among cis-regulatory variants can shape quantitative variation, and suggest that empirical dissections of this hidden complexity can guide promoter engineering to predictably modify crop traits.
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Affiliation(s)
- Xingang Wang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Lyndsey Aguirre
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Daniel Rodríguez-Leal
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Inari Agriculture, Cambridge, MA, USA
| | - Anat Hendelman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Matthias Benoit
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Zachary B Lippman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
- School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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41
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Yuan X, Scott IC, Wilson MD. Heart Enhancers: Development and Disease Control at a Distance. Front Genet 2021; 12:642975. [PMID: 33777110 PMCID: PMC7987942 DOI: 10.3389/fgene.2021.642975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 01/29/2021] [Indexed: 12/14/2022] Open
Abstract
Bound by lineage-determining transcription factors and signaling effectors, enhancers play essential roles in controlling spatiotemporal gene expression profiles during development, homeostasis and disease. Recent synergistic advances in functional genomic technologies, combined with the developmental biology toolbox, have resulted in unprecedented genome-wide annotation of heart enhancers and their target genes. Starting with early studies of vertebrate heart enhancers and ending with state-of-the-art genome-wide enhancer discovery and testing, we will review how studying heart enhancers in metazoan species has helped inform our understanding of cardiac development and disease.
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Affiliation(s)
- Xuefei Yuan
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ian C. Scott
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Michael D. Wilson
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
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42
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Jindal GA, Farley EK. Enhancer grammar in development, evolution, and disease: dependencies and interplay. Dev Cell 2021; 56:575-587. [PMID: 33689769 PMCID: PMC8462829 DOI: 10.1016/j.devcel.2021.02.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 02/15/2021] [Accepted: 02/16/2021] [Indexed: 12/19/2022]
Abstract
Each language has standard books describing that language's grammatical rules. Biologists have searched for similar, albeit more complex, principles relating enhancer sequence to gene expression. Here, we review the literature on enhancer grammar. We introduce dependency grammar, a model where enhancers encode information based on dependencies between enhancer features shaped by mechanistic, evolutionary, and biological constraints. Classifying enhancers based on the types of dependencies may identify unifying principles relating enhancer sequence to gene expression. Such rules would allow us to read the instructions for development within genomes and pinpoint causal enhancer variants underlying disease and evolutionary changes.
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Affiliation(s)
- Granton A Jindal
- Division of Cardiology, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; Division of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Emma K Farley
- Division of Cardiology, Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; Division of Biological Sciences, Section of Molecular Biology, University of California San Diego, La Jolla, CA 92093, USA.
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43
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Hendelman A, Zebell S, Rodriguez-Leal D, Dukler N, Robitaille G, Wu X, Kostyun J, Tal L, Wang P, Bartlett ME, Eshed Y, Efroni I, Lippman ZB. Conserved pleiotropy of an ancient plant homeobox gene uncovered by cis-regulatory dissection. Cell 2021; 184:1724-1739.e16. [PMID: 33667348 DOI: 10.1016/j.cell.2021.02.001] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/03/2021] [Accepted: 02/01/2021] [Indexed: 01/09/2023]
Abstract
Divergence of gene function is a hallmark of evolution, but assessing functional divergence over deep time is not trivial. The few alleles available for cross-species studies often fail to expose the entire functional spectrum of genes, potentially obscuring deeply conserved pleiotropic roles. Here, we explore the functional divergence of WUSCHEL HOMEOBOX9 (WOX9), suggested to have species-specific roles in embryo and inflorescence development. Using a cis-regulatory editing drive system, we generate a comprehensive allelic series in tomato, which revealed hidden pleiotropic roles for WOX9. Analysis of accessible chromatin and conserved cis-regulatory sequences identifies the regions responsible for this pleiotropic activity, the functions of which are conserved in groundcherry, a tomato relative. Mimicking these alleles in Arabidopsis, distantly related to tomato and groundcherry, reveals new inflorescence phenotypes, exposing a deeply conserved pleiotropy. We suggest that targeted cis-regulatory mutations can uncover conserved gene functions and reduce undesirable effects in crop improvement.
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Affiliation(s)
- Anat Hendelman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Sophia Zebell
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | | | - Noah Dukler
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Gina Robitaille
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Xuelin Wu
- The Salk Institute for Biological Research, San Diego, CA, USA
| | - Jamie Kostyun
- Biology Department, University of Massachusetts Amherst, Amherst, MA, USA
| | - Lior Tal
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Peipei Wang
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, The Hebrew University, Rehovot, Israel
| | | | - Yuval Eshed
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Idan Efroni
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, The Hebrew University, Rehovot, Israel.
| | - Zachary B Lippman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA; Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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44
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Kittelmann S, Preger-Ben Noon E, McGregor AP, Frankel N. A complex gene regulatory architecture underlies the development and evolution of cuticle morphology in Drosophila. Curr Opin Genet Dev 2021; 69:21-27. [PMID: 33529925 DOI: 10.1016/j.gde.2021.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/18/2020] [Accepted: 01/05/2021] [Indexed: 10/22/2022]
Abstract
The cuticle of insects is decorated with non-sensory hairs called trichomes. A few Drosophila species independently lost most of the dorso-lateral trichomes on first instar larvae. Genetic experiments revealed that this naked cuticle phenotype was caused by the evolution of enhancer function at the ovo/shavenbaby (ovo/svb) locus. Here we explore how this discovery catalyzed major new insights into morphological evolution in different developmental contexts, enhancer pleiotropy in gene regulation and the functionality and evolution of the Svb gene regulatory network (GRN). Taken together this highlights the importance of understanding the architecture and evolution of gene regulatory networks in detail and the great potential for further study of the Svb GRN.
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Affiliation(s)
- Sebastian Kittelmann
- Centre for Functional Genomics, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Ella Preger-Ben Noon
- Department of Genetics and Developmental Biology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa 3109601, Israel
| | - Alistair P McGregor
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom
| | - Nicolás Frankel
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE, CONICET-UBA), Buenos Aires 1428, Argentina; Departamento de Ecología, Genética y Evolución (FCEyN, UBA), Buenos Aires 1428, Argentina.
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45
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Molecular and evolutionary processes generating variation in gene expression. Nat Rev Genet 2020; 22:203-215. [PMID: 33268840 DOI: 10.1038/s41576-020-00304-w] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2020] [Indexed: 12/18/2022]
Abstract
Heritable variation in gene expression is common within and between species. This variation arises from mutations that alter the form or function of molecular gene regulatory networks that are then filtered by natural selection. High-throughput methods for introducing mutations and characterizing their cis- and trans-regulatory effects on gene expression (particularly, transcription) are revealing how different molecular mechanisms generate regulatory variation, and studies comparing these mutational effects with variation seen in the wild are teasing apart the role of neutral and non-neutral evolutionary processes. This integration of molecular and evolutionary biology allows us to understand how the variation in gene expression we see today came to be and to predict how it is most likely to evolve in the future.
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46
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Le Poul Y, Xin Y, Ling L, Mühling B, Jaenichen R, Hörl D, Bunk D, Harz H, Leonhardt H, Wang Y, Osipova E, Museridze M, Dharmadhikari D, Murphy E, Rohs R, Preibisch S, Prud'homme B, Gompel N. Regulatory encoding of quantitative variation in spatial activity of a Drosophila enhancer. SCIENCE ADVANCES 2020; 6:6/49/eabe2955. [PMID: 33268361 PMCID: PMC7821883 DOI: 10.1126/sciadv.abe2955] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/20/2020] [Indexed: 06/12/2023]
Abstract
Developmental enhancers control the expression of genes prefiguring morphological patterns. The activity of an enhancer varies among cells of a tissue, but collectively, expression levels in individual cells constitute a spatial pattern of gene expression. How the spatial and quantitative regulatory information is encoded in an enhancer sequence is elusive. To link spatial pattern and activity levels of an enhancer, we used systematic mutations of the yellow spot enhancer, active in developing Drosophila wings, and tested their effect in a reporter assay. Moreover, we developed an analytic framework based on the comprehensive quantification of spatial reporter activity. We show that the quantitative enhancer activity results from densely packed regulatory information along the sequence, and that a complex interplay between activators and multiple tiers of repressors carves the spatial pattern. Our results shed light on how an enhancer reads and integrates trans-regulatory landscape information to encode a spatial quantitative pattern.
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Affiliation(s)
- Yann Le Poul
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Yaqun Xin
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Liucong Ling
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Bettina Mühling
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Rita Jaenichen
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - David Hörl
- Human Biology and Bioimaging, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - David Bunk
- Human Biology and Bioimaging, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Hartmann Harz
- Human Biology and Bioimaging, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Heinrich Leonhardt
- Human Biology and Bioimaging, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Yingfei Wang
- Quantitative and Computational Biology, Departments of Biological Sciences, Chemistry, Physics and Astronomy, and Computer Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Elena Osipova
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Mariam Museridze
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Deepak Dharmadhikari
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Eamonn Murphy
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany
| | - Remo Rohs
- Quantitative and Computational Biology, Departments of Biological Sciences, Chemistry, Physics and Astronomy, and Computer Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Stephan Preibisch
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Robert-Rössle-Str. 10, 13092 Berlin, Germany
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Benjamin Prud'homme
- Aix-Marseille Université, CNRS, IBDM, Institut de Biologie du Développement de Marseille, Campus de Luminy Case 907, 13288 Marseille Cedex 9, France.
| | - Nicolas Gompel
- Evolutionary Ecology, Ludwig-Maximilians Universität München, Fakultät für Biologie, Biozentrum, Grosshaderner Strasse 2, 82152 Planegg-Martinsried, Germany.
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