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Mulero-Hernández J, Mironov V, Miñarro-Giménez JA, Kuiper M, Fernández-Breis JT. Integration of chromosome locations and functional aspects of enhancers and topologically associating domains in knowledge graphs enables versatile queries about gene regulation. Nucleic Acids Res 2024:gkae566. [PMID: 38967009 DOI: 10.1093/nar/gkae566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/12/2024] [Accepted: 06/19/2024] [Indexed: 07/06/2024] Open
Abstract
Knowledge about transcription factor binding and regulation, target genes, cis-regulatory modules and topologically associating domains is not only defined by functional associations like biological processes or diseases but also has a determinative genome location aspect. Here, we exploit these location and functional aspects together to develop new strategies to enable advanced data querying. Many databases have been developed to provide information about enhancers, but a schema that allows the standardized representation of data, securing interoperability between resources, has been lacking. In this work, we use knowledge graphs for the standardized representation of enhancers and topologically associating domains, together with data about their target genes, transcription factors, location on the human genome, and functional data about diseases and gene ontology annotations. We used this schema to integrate twenty-five enhancer datasets and two domain datasets, creating the most powerful integrative resource in this field to date. The knowledge graphs have been implemented using the Resource Description Framework and integrated within the open-access BioGateway knowledge network, generating a resource that contains an interoperable set of knowledge graphs (enhancers, TADs, genes, proteins, diseases, GO terms, and interactions between domains). We show how advanced queries, which combine functional and location restrictions, can be used to develop new hypotheses about functional aspects of gene expression regulation.
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Affiliation(s)
- Juan Mulero-Hernández
- Departamento de Informática y Sistemas, Universidad de Murcia, CEIR Campus Mare Nostrum, Instituto Murciano de Investigación Biosanitaria (IMIB),30100 Murcia, Spain
| | - Vladimir Mironov
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - José Antonio Miñarro-Giménez
- Departamento de Informática y Sistemas, Universidad de Murcia, CEIR Campus Mare Nostrum, Instituto Murciano de Investigación Biosanitaria (IMIB),30100 Murcia, Spain
| | - Martin Kuiper
- Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Jesualdo Tomás Fernández-Breis
- Departamento de Informática y Sistemas, Universidad de Murcia, CEIR Campus Mare Nostrum, Instituto Murciano de Investigación Biosanitaria (IMIB),30100 Murcia, Spain
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2
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Viitaniemi HM, Leder EH, Kauzál O, Stopková R, Stopka P, Lifjeld JT, Albrecht T. Impact of Z chromosome inversions on gene expression in testis and liver tissues in the zebra finch. Mol Ecol 2023. [PMID: 38126688 DOI: 10.1111/mec.17236] [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: 06/13/2023] [Revised: 10/10/2023] [Accepted: 10/24/2023] [Indexed: 12/23/2023]
Abstract
Chromosomal inversions have been identified in many natural populations and can be responsible for novel traits and rapid adaptation. In zebra finch, a large region on the Z chromosome has been subject to multiple inversions, which have pleiotropic effects on multiple traits but especially on sperm phenotypes, such as midpiece and flagellum length. To understand the effect, the Z inversion has on these traits, we examined testis and liver transcriptomes of young males at different maturation times. We compared gene expression differences among three inversion karyotypes: AA, B*B* and AB*, where B* denotes the inverted regions on Z with respect to A. In testis, 794 differentially expressed genes were found and most of them were located on chromosome Z. They were functionally enriched for sperm-related traits. We also identified clusters of co-expressed genes that matched with the inversion-related sperm phenotypes. In liver, there were some enriched functions and some overrepresentation on chromosome Z with similar location as in testis. In both tissues, the overrepresented genes were located near the distal end of Z but also in the middle of the chromosome. For the heterokaryotype, we observed several genes with one allele being dominantly expressed, similar to expression patterns in one or the other homokaryotype. This was confirmed with SNPs for three genes, and interestingly one gene, DMGDH, had allele-specific expression originating mainly from one inversion haplotype in the testis, yet both inversion haplotypes were expressed equally in the liver. This karyotype-specific difference in tissue-specific expression suggests a pleiotropic effect of the inversion and thus suggests a mechanism for divergent phenotypic effects resulting from an inversion.
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Affiliation(s)
- Heidi M Viitaniemi
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Section of Ecology and Evolution, Department of Biology, University of Turku, Turku, Finland
| | - Erica H Leder
- Section of Ecology and Evolution, Department of Biology, University of Turku, Turku, Finland
- Tjärnö Marine Laboratory, Department of Marine Sciences, University of Gothenburg, Strömstad, Sweden
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Ondřej Kauzál
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
| | - Romana Stopková
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Pavel Stopka
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jan T Lifjeld
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Tomáš Albrecht
- Institute of Vertebrate Biology, Czech Academy of Sciences, Brno, Czech Republic
- Department of Zoology, Faculty of Science, Charles University, Prague, Czech Republic
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3
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Tian W, Zhou J, Bartlett A, Zeng Q, Liu H, Castanon RG, Kenworthy M, Altshul J, Valadon C, Aldridge A, Nery JR, Chen H, Xu J, Johnson ND, Lucero J, Osteen JK, Emerson N, Rink J, Lee J, Li Y, Siletti K, Liem M, Claffey N, O’Connor C, Yanny AM, Nyhus J, Dee N, Casper T, Shapovalova N, Hirschstein D, Ding SL, Hodge R, Levi BP, Keene CD, Linnarsson S, Lein E, Ren B, Behrens MM, Ecker JR. Single-cell DNA methylation and 3D genome architecture in the human brain. Science 2023; 382:eadf5357. [PMID: 37824674 PMCID: PMC10572106 DOI: 10.1126/science.adf5357] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 09/05/2023] [Indexed: 10/14/2023]
Abstract
Delineating the gene-regulatory programs underlying complex cell types is fundamental for understanding brain function in health and disease. Here, we comprehensively examined human brain cell epigenomes by probing DNA methylation and chromatin conformation at single-cell resolution in 517 thousand cells (399 thousand neurons and 118 thousand non-neurons) from 46 regions of three adult male brains. We identified 188 cell types and characterized their molecular signatures. Integrative analyses revealed concordant changes in DNA methylation, chromatin accessibility, chromatin organization, and gene expression across cell types, cortical areas, and basal ganglia structures. We further developed single-cell methylation barcodes that reliably predict brain cell types using the methylation status of select genomic sites. This multimodal epigenomic brain cell atlas provides new insights into the complexity of cell-type-specific gene regulation in adult human brains.
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Affiliation(s)
- Wei Tian
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jingtian Zhou
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Bioinformatics and Systems Biology Program, University of California, San Diego, La Jolla, CA 92037, USA
| | - Anna Bartlett
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Qiurui Zeng
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92037, USA
| | - Hanqing Liu
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Rosa G. Castanon
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Mia Kenworthy
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jordan Altshul
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Cynthia Valadon
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Andrew Aldridge
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Joseph R. Nery
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Huaming Chen
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jiaying Xu
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Nicholas D. Johnson
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jacinta Lucero
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Julia K. Osteen
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Nora Emerson
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jon Rink
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Jasper Lee
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Yang Li
- Ludwig Institute for Cancer Research, La Jolla, CA 92037, USA
| | - Kimberly Siletti
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet; 171 77 Stockholm, Sweden
| | - Michelle Liem
- Flow Cytometry Core Facility, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Naomi Claffey
- Flow Cytometry Core Facility, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Caz O’Connor
- Flow Cytometry Core Facility, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | | | - Julie Nyhus
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | - Nick Dee
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | - Tamara Casper
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | | | | | - Song-Lin Ding
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | - Rebecca Hodge
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | - Boaz P. Levi
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | - C. Dirk Keene
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Sten Linnarsson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet; 171 77 Stockholm, Sweden
| | - Ed Lein
- Allen Institute for Brain Science; Seattle, WA 98109, USA
| | - Bing Ren
- Ludwig Institute for Cancer Research, La Jolla, CA 92037, USA
- Center for Epigenomics, University of California, San Diego School of Medicine, La Jolla, CA 92037, USA
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92037, USA
- Institute of Genomic Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92037, USA
- Moores Cancer Center, University of California, San Diego School of Medicine, La Jolla, CA 92037, USA
| | - M. Margarita Behrens
- Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Joseph R. Ecker
- Genomic Analysis Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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4
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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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5
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Vespasiani DM, Jacobs GS, Cook LE, Brucato N, Leavesley M, Kinipi C, Ricaut FX, Cox MP, Gallego Romero I. Denisovan introgression has shaped the immune system of present-day Papuans. PLoS Genet 2022; 18:e1010470. [PMID: 36480515 PMCID: PMC9731433 DOI: 10.1371/journal.pgen.1010470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 10/10/2022] [Indexed: 12/13/2022] Open
Abstract
Modern humans have admixed with multiple archaic hominins. Papuans, in particular, owe up to 5% of their genome to Denisovans, a sister group to Neanderthals whose remains have only been identified in Siberia and Tibet. Unfortunately, the biological and evolutionary significance of these introgression events remain poorly understood. Here we investigate the function of both Denisovan and Neanderthal alleles characterised within a set of 56 genomes from Papuan individuals. By comparing the distribution of archaic and non-archaic variants we assess the consequences of archaic admixture across a multitude of different cell types and functional elements. We observe an enrichment of archaic alleles within cis-regulatory elements and transcribed regions of the genome, with Denisovan variants strongly affecting elements active within immune-related cells. We identify 16,048 and 10,032 high-confidence Denisovan and Neanderthal variants that fall within annotated cis-regulatory elements and with the potential to alter the affinity of multiple transcription factors to their cognate DNA motifs, highlighting a likely mechanism by which introgressed DNA can impact phenotypes. Lastly, we experimentally validate these predictions by testing the regulatory potential of five Denisovan variants segregating within Papuan individuals, and find that two are associated with a significant reduction of transcriptional activity in plasmid reporter assays. Together, these data provide support for a widespread contribution of archaic DNA in shaping the present levels of modern human genetic diversity, with different archaic ancestries potentially affecting multiple phenotypic traits within non-Africans.
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Affiliation(s)
- Davide M. Vespasiani
- Melbourne Integrative Genomics, University of Melbourne, Parkville, Australia
- School of Biosciences, University of Melbourne, Parkville, Australia
| | - Guy S. Jacobs
- Department of Archaeology, University of Cambridge, Cambridge, Uniteed Kingdom
| | - Laura E. Cook
- Melbourne Integrative Genomics, University of Melbourne, Parkville, Australia
- School of Biosciences, University of Melbourne, Parkville, Australia
| | - Nicolas Brucato
- Laboratoire de Evolution et Diversite Biologique, Université de Toulouse Midi-Pyrénées, Toulouse, France
| | - Matthew Leavesley
- School of Humanities and Social Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
- College of Arts, Society and Education, James Cook University, Cairns, Australia
- ARC Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, Australia
| | - Christopher Kinipi
- School of Humanities and Social Sciences, University of Papua New Guinea, Port Moresby, Papua New Guinea
| | - François-Xavier Ricaut
- Laboratoire de Evolution et Diversite Biologique, Université de Toulouse Midi-Pyrénées, Toulouse, France
| | - Murray P. Cox
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Irene Gallego Romero
- Melbourne Integrative Genomics, University of Melbourne, Parkville, Australia
- School of Biosciences, University of Melbourne, Parkville, Australia
- Center for Stem Cell Systems, University of Melbourne, Parkville, Australia
- Center for Genomics, Evolution and Medicine, University of Tartu, Tartu, Estonia
- * E-mail:
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6
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Current challenges in understanding the role of enhancers in disease. Nat Struct Mol Biol 2022; 29:1148-1158. [PMID: 36482255 DOI: 10.1038/s41594-022-00896-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/04/2022] [Indexed: 12/13/2022]
Abstract
Enhancers play a central role in the spatiotemporal control of gene expression and tend to work in a cell-type-specific manner. In addition, they are suggested to be major contributors to phenotypic variation, evolution and disease. There is growing evidence that enhancer dysfunction due to genetic, structural or epigenetic mechanisms contributes to a broad range of human diseases referred to as enhanceropathies. Such mechanisms often underlie the susceptibility to common diseases, but can also play a direct causal role in cancer or Mendelian diseases. Despite the recent gain of insights into enhancer biology and function, we still have a limited ability to predict how enhancer dysfunction impacts gene expression. Here we discuss the major challenges that need to be overcome when studying the role of enhancers in disease etiology and highlight opportunities and directions for future studies, aiming to disentangle the molecular basis of enhanceropathies.
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7
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Pang B, van Weerd JH, Hamoen FL, Snyder MP. Identification of non-coding silencer elements and their regulation of gene expression. Nat Rev Mol Cell Biol 2022; 24:383-395. [DOI: 10.1038/s41580-022-00549-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/29/2022] [Indexed: 11/09/2022]
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8
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Rowley AJ, Square TA, Miller CT. Site pleiotropy of a stickleback Bmp6 enhancer. Dev Biol 2022; 492:111-118. [PMID: 36198347 DOI: 10.1016/j.ydbio.2022.09.012] [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: 05/13/2022] [Revised: 09/27/2022] [Accepted: 09/28/2022] [Indexed: 11/15/2022]
Abstract
Development and regeneration are orchestrated by gene regulatory networks that operate in part through transcriptional enhancers. Although many enhancers are pleiotropic and are active in multiple tissues, little is known about whether enhancer pleiotropy is due to 1) site pleiotropy, in which individual transcription factor binding sites (TFBS) are required for activity in multiple tissues, or 2) multiple distinct sites that regulate expression in different tissues. Here, we investigated the pleiotropy of an intronic enhancer of the stickleback Bone morphogenetic protein 6 (Bmp6) gene. This enhancer was previously shown to regulate evolved changes in tooth number and tooth regeneration, and is highly pleiotropic, with robust activity in both fins and teeth throughout embryonic, larval, and adult life, and in the heart and kidney in adult fish. We tested the hypothesis that the pleiotropy of this enhancer is due to site pleiotropy of an evolutionarily conserved predicted Foxc1 TFBS. Transgenic analysis and site-directed mutagenesis experiments both deleting and scrambling this predicted Foxc1 TFBS revealed that the binding site is required for enhancer activity in both teeth and fins throughout embryonic, larval, and adult development, and in the heart and kidney in adult fish. Collectively these data support a model where the pleiotropy of this Bmp6 enhancer is due to site pleiotropy and this putative binding site is required for enhancer activity in multiple anatomical sites from the embryo to the adult.
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Affiliation(s)
- Alyssa J Rowley
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA, 94720, USA
| | - Tyler A Square
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA, 94720, USA
| | - Craig T Miller
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA, 94720, USA.
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9
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Pereira AG, Grizante MB, Kohlsdorf T. What snakes and caecilians have in common? Molecular interaction units and the independent origins of similar morphotypes in Tetrapoda. Proc Biol Sci 2022; 289:20220841. [PMID: 35975445 PMCID: PMC9382212 DOI: 10.1098/rspb.2022.0841] [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: 05/01/2022] [Accepted: 07/25/2022] [Indexed: 12/14/2022] Open
Abstract
Developmental pathways encompass transcription factors and cis-regulatory elements that interact as transcription factor-regulatory element (TF-RE) units. Independent origins of similar phenotypes likely involve changes in different parts of these units, a hypothesis promisingly tested addressing the evolution of the rib-associated lumbar (RAL) morphotype that characterizes emblematic animals such as snakes and elephants. Previous investigation in these lineages identified a polymorphism in the Homology region 1 [H1] enhancer of the Myogenic factor-5 [Myf5], which interacts with HOX10 proteins to modulate rib development. Here we address the evolution of TF-RE units focusing on independent origins of RAL morphotypes. We compiled an extensive database for H1-Myf5 and HOX10 sequences with two goals: (i) evaluate if the enhancer polymorphism is present in amphibians exhibiting the RAL morphotype and (ii) test a hypothesis of enhanced evolutionary flexibility mediated by TF-RE units, according to which independent origins of the RAL morphotype might involve changes in either component of the interaction unit. We identified the H1-Myf5 polymorphism in lineages that diverged around 340 Ma, including Lissamphibia. Independent origins of the RAL morphotype in Tetrapoda involved sequence variation in either component of the TF-RE unit, confirming that different changes may similarly affect the phenotypic outcome of a given developmental pathway.
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Affiliation(s)
- Anieli G. Pereira
- Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Mariana B. Grizante
- Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Dante Pazzanese Institute of Cardiology, Sao Paulo, Brazil
| | - Tiana Kohlsdorf
- Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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10
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Abstract
The rediscovery of Mendel’s work showing that the heredity of phenotypes is controlled by discrete genes was followed by the reconciliation of Mendelian genetics with evolution by natural selection in the middle of the last century with the Modern Synthesis. In the past two decades, dramatic advances in genomic methods have facilitated the identification of the loci, genes, and even individual mutations that underlie phenotypic variants that are the putative targets of natural selection. Moreover, these methods have also changed how we can study adaptation by flipping the problem around, allowing us to first examine what loci show evidence of having been under selection, and then connecting these genetic variants to phenotypic variation. As a result, we now have an expanding list of actual genetic changes that underlie potentially adaptive phenotypic variation. Here, we synthesize how considering the effects of these adaptive loci in the context of cellular environments, genomes, organisms, and populations has provided new insights to the genetic architecture of adaptation.
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11
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Mulero Hernández J, Fernández-Breis JT. Analysis of the landscape of human enhancer sequences in biological databases. Comput Struct Biotechnol J 2022; 20:2728-2744. [PMID: 35685360 PMCID: PMC9168495 DOI: 10.1016/j.csbj.2022.05.045] [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: 03/28/2022] [Revised: 05/20/2022] [Accepted: 05/21/2022] [Indexed: 12/01/2022] Open
Abstract
The process of gene regulation extends as a network in which both genetic sequences and proteins are involved. The levels of regulation and the mechanisms involved are multiple. Transcription is the main control mechanism for most genes, being the downstream steps responsible for refining the transcription patterns. In turn, gene transcription is mainly controlled by regulatory events that occur at promoters and enhancers. Several studies are focused on analyzing the contribution of enhancers in the development of diseases and their possible use as therapeutic targets. The study of regulatory elements has advanced rapidly in recent years with the development and use of next generation sequencing techniques. All this information has generated a large volume of information that has been transferred to a growing number of public repositories that store this information. In this article, we analyze the content of those public repositories that contain information about human enhancers with the aim of detecting whether the knowledge generated by scientific research is contained in those databases in a way that could be computationally exploited. The analysis will be based on three main aspects identified in the literature: types of enhancers, type of evidence about the enhancers, and methods for detecting enhancer-promoter interactions. Our results show that no single database facilitates the optimal exploitation of enhancer data, most types of enhancers are not represented in the databases and there is need for a standardized model for enhancers. We have identified major gaps and challenges for the computational exploitation of enhancer data.
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Affiliation(s)
- Juan Mulero Hernández
- Dept. Informática y Sistemas, Universidad de Murcia, CEIR Campus Mare Nostrum, IMIB-Arrixaca, Spain
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12
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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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13
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Laiker I, Frankel N. Pleiotropic enhancers are ubiquitous regulatory elements in the human genome. Genome Biol Evol 2022; 14:6585219. [PMID: 35552697 PMCID: PMC9156028 DOI: 10.1093/gbe/evac071] [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] [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
| | - Nicolas 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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14
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McDonald JMC, Reed RD. Patterns of selection across gene regulatory networks. Semin Cell Dev Biol 2022; 145:60-67. [PMID: 35474149 DOI: 10.1016/j.semcdb.2022.03.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 01/31/2022] [Accepted: 03/23/2022] [Indexed: 12/29/2022]
Abstract
Gene regulatory networks (GRNs) are the core engine of organismal development. If we would like to understand the origin and diversification of phenotypes, it is necessary to consider the structure of GRNs in order to reconstruct the links between genetic mutations and phenotypic change. Much of the progress in evolutionary developmental biology, however, has occurred without a nuanced consideration of the evolution of functional relationships between genes, especially in the context of their broader network interactions. Characterizing and comparing GRNs across traits and species in a more detailed way will allow us to determine how network position influences what genes drive adaptive evolution. In this perspective paper, we consider the architecture of developmental GRNs and how positive selection strength may vary across a GRN. We then propose several testable models for these patterns of selection and experimental approaches to test these models.
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Affiliation(s)
- Jeanne M C McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
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15
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Akiyama N, Sato S, Tanaka KM, Sakai T, Takahashi A. The role of the epidermis enhancer element in positive and negative transcriptional regulation of ebony in Drosophila melanogaster. G3 GENES|GENOMES|GENETICS 2022; 12:6506522. [PMID: 35100378 PMCID: PMC8895987 DOI: 10.1093/g3journal/jkac010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/06/2022] [Indexed: 11/15/2022]
Abstract
The spatiotemporal regulation of gene expression is essential to ensure robust phenotypic outcomes. Pigmentation patterns in Drosophila are determined by pigments biosynthesized in the developing epidermis and the cis-regulatory elements of the genes involved in this process are well-characterized. Here, we report that the known primary epidermal enhancer is dispensable for the transcriptional activation of ebony (involved in light-colored pigment synthesis) in the developing epidermis of Drosophila melanogaster. The evidence was obtained by introducing an approximately 1 kbp deletion at the primary epidermal enhancer by genome editing. The effect of the primary epidermal enhancer deletion on pigmentation and on the endogenous expression pattern of a mCherry-fused ebony allele was examined in the abdomen. The expression levels of the mCherry-fused ebony in the primary epidermal enhancer-deleted strains were slightly higher than that of the control strain, indicating that the sequences outside the primary epidermal enhancer have an ability to drive an expression of this gene in the epidermis. Interestingly, the primary epidermal enhancer deletion resulted in a derepression of this gene in the dorsal midline of the abdominal tergites, where dark pigmentation is present in the wild-type individuals. This indicated that the primary epidermal enhancer fragment contains a silencer. Furthermore, the endogenous expression pattern of ebony in the 2 additional strains with partially deleted primary epidermal enhancer revealed that the silencer resides within a 351-bp fragment in the 5' portion of the primary epidermal enhancer. These results demonstrated that deletion assays combined with reporter assays are highly effective in detecting the presence of positively and negatively regulating sequences within and outside the focal cis-regulatory elements.
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Affiliation(s)
- Noriyoshi Akiyama
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Shoma Sato
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Kentaro M Tanaka
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Takaomi Sakai
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Aya Takahashi
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji 192-0397, Japan
- Research Center for Genomics and Bioinformatics, Tokyo Metropolitan University, Hachioji 192-0397, Japan
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16
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Luecke D, Rice G, Kopp A. Sex-specific evolution of a Drosophila sensory system via interacting cis- and trans-regulatory changes. Evol Dev 2022; 24:37-60. [PMID: 35239254 PMCID: PMC9179014 DOI: 10.1111/ede.12398] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 01/20/2022] [Accepted: 01/25/2022] [Indexed: 12/13/2022]
Abstract
The evolution of gene expression via cis-regulatory changes is well established as a major driver of phenotypic evolution. However, relatively little is known about the influence of enhancer architecture and intergenic interactions on regulatory evolution. We address this question by examining chemosensory system evolution in Drosophila. Drosophila prolongata males show a massively increased number of chemosensory bristles compared to females and males of sibling species. This increase is driven by sex-specific transformation of ancestrally mechanosensory organs. Consistent with this phenotype, the Pox neuro transcription factor (Poxn), which specifies chemosensory bristle identity, shows expanded expression in D. prolongata males. Poxn expression is controlled by nonadditive interactions among widely dispersed enhancers. Although some D. prolongata Poxn enhancers show increased activity, the additive component of this increase is slight, suggesting that most changes in Poxn expression are due to epistatic interactions between Poxn enhancers and trans-regulatory factors. Indeed, the expansion of D. prolongata Poxn enhancer activity is only observed in cells that express doublesex (dsx), the gene that controls sexual differentiation in Drosophila and also shows increased expression in D. prolongata males due to cis-regulatory changes. Although expanded dsx expression may contribute to increased activity of D. prolongata Poxn enhancers, this interaction is not sufficient to explain the full expansion of Poxn expression, suggesting that cis-trans interactions between Poxn, dsx, and additional unknown genes are necessary to produce the derived D. prolongata phenotype. Overall, our results demonstrate the importance of epistatic gene interactions for evolution, particularly when pivotal genes have complex regulatory architecture.
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Affiliation(s)
- David Luecke
- Department of Evolution and Ecology, University of California – Davis,Current Address: Department of Integrative Biology, Michigan State University
| | - Gavin Rice
- Department of Evolution and Ecology, University of California – Davis,Current Address: Department of Biological Sciences, University of Pittsburgh
| | - Artyom Kopp
- Department of Evolution and Ecology, University of California – Davis
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17
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Butterfly eyespots evolved via cooption of an ancestral gene-regulatory network that also patterns antennae, legs, and wings. Proc Natl Acad Sci U S A 2022; 119:2108661119. [PMID: 35169073 PMCID: PMC8872758 DOI: 10.1073/pnas.2108661119] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2022] [Indexed: 12/13/2022] Open
Abstract
Where do butterfly eyespots come from? One of the long-standing questions in the field of evolution concerns addressing where novel complex traits come from. Here we show that butterfly eyespots, a novel complex trait, likely originated from the redeployment of a preexisting gene-regulatory network regulating antennae, legs, and wings, to novel locations on the wing. Butterfly eyespots are beautiful novel traits with an unknown developmental origin. Here we show that eyespots likely originated via cooption of parts of an ancestral appendage gene-regulatory network (GRN) to novel locations on the wing. Using comparative transcriptome analysis, we show that eyespots cluster most closely with antennae, relative to multiple other tissues. Furthermore, three genes essential for eyespot development, Distal-less (Dll), spalt (sal), and Antennapedia (Antp), share similar regulatory connections as those observed in the antennal GRN. CRISPR knockout of cis-regulatory elements (CREs) for Dll and sal led to the loss of eyespots, antennae, legs, and also wings, demonstrating that these CREs are highly pleiotropic. We conclude that eyespots likely reused an ancient GRN for their development, a network also previously implicated in the development of antennae, legs, and wings.
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18
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Schmitz RJ, Grotewold E, Stam M. Cis-regulatory sequences in plants: Their importance, discovery, and future challenges. THE PLANT CELL 2022; 34:718-741. [PMID: 34918159 PMCID: PMC8824567 DOI: 10.1093/plcell/koab281] [Citation(s) in RCA: 110] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/20/2021] [Indexed: 05/19/2023]
Abstract
The identification and characterization of cis-regulatory DNA sequences and how they function to coordinate responses to developmental and environmental cues is of paramount importance to plant biology. Key to these regulatory processes are cis-regulatory modules (CRMs), which include enhancers and silencers. Despite the extraordinary advances in high-quality sequence assemblies and genome annotations, the identification and understanding of CRMs, and how they regulate gene expression, lag significantly behind. This is especially true for their distinguishing characteristics and activity states. Here, we review the current knowledge on CRMs and breakthrough technologies enabling identification, characterization, and validation of CRMs; we compare the genomic distributions of CRMs with respect to their target genes between different plant species, and discuss the role of transposable elements harboring CRMs in the evolution of gene expression. This is an exciting time to study cis-regulomes in plants; however, significant existing challenges need to be overcome to fully understand and appreciate the role of CRMs in plant biology and in crop improvement.
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Affiliation(s)
- Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Erich Grotewold
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, USA
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19
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Kopania EEK, Larson EL, Callahan C, Keeble S, Good JM. Molecular Evolution across Mouse Spermatogenesis. Mol Biol Evol 2022; 39:6517785. [PMID: 35099536 PMCID: PMC8844503 DOI: 10.1093/molbev/msac023] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genes involved in spermatogenesis tend to evolve rapidly, but we lack a clear understanding of how protein sequences and patterns of gene expression evolve across this complex developmental process. We used fluorescence-activated cell sorting (FACS) to generate expression data for early (meiotic) and late (postmeiotic) cell types across 13 inbred strains of mice (Mus) spanning ∼7 My of evolution. We used these comparative developmental data to investigate the evolution of lineage-specific expression, protein-coding sequences, and expression levels. We found increased lineage specificity and more rapid protein-coding and expression divergence during late spermatogenesis, suggesting that signatures of rapid testis molecular evolution are punctuated across sperm development. Despite strong overall developmental parallels in these components of molecular evolution, protein and expression divergences were only weakly correlated across genes. We detected more rapid protein evolution on the X chromosome relative to the autosomes, whereas X-linked gene expression tended to be relatively more conserved likely reflecting chromosome-specific regulatory constraints. Using allele-specific FACS expression data from crosses between four strains, we found that the relative contributions of different regulatory mechanisms also differed between cell types. Genes showing cis-regulatory changes were more common late in spermatogenesis, and tended to be associated with larger differences in expression levels and greater expression divergence between species. In contrast, genes with trans-acting changes were more common early and tended to be more conserved across species. Our findings advance understanding of gene evolution across spermatogenesis and underscore the fundamental importance of developmental context in molecular evolutionary studies.
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Affiliation(s)
- Emily E K Kopania
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Erica L Larson
- Department of Biological Sciences, University of Denver, Denver, CO, 80208, USA
| | - Colin Callahan
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Sara Keeble
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Jeffrey M Good
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA
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20
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Stepaniak MD, Square TA, Miller CT. Evolved Bmp6 enhancer alleles drive spatial shifts in gene expression during tooth development in sticklebacks. Genetics 2021; 219:6374454. [PMID: 34849839 PMCID: PMC8664583 DOI: 10.1093/genetics/iyab151] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
Mutations in enhancers have been shown to often underlie natural variation but the evolved differences in enhancer activity can be difficult to identify in vivo. Threespine sticklebacks (Gasterosteus aculeatus) are a robust system for studying enhancer evolution due to abundant natural genetic variation, a diversity of evolved phenotypes between ancestral marine and derived freshwater forms, and the tractability of transgenic techniques. Previous work identified a series of polymorphisms within an intronic enhancer of the Bone morphogenetic protein 6 (Bmp6) gene that are associated with evolved tooth gain, a derived increase in freshwater tooth number that arises late in development. Here, we use a bicistronic reporter construct containing a genetic insulator and a pair of reciprocal two-color transgenic reporter lines to compare enhancer activity of marine and freshwater alleles of this enhancer. In older fish, the two alleles drive partially overlapping expression in both mesenchyme and epithelium of developing teeth, but the freshwater enhancer drives a reduced mesenchymal domain and a larger epithelial domain relative to the marine enhancer. In younger fish, these spatial shifts in enhancer activity are less pronounced. Comparing Bmp6 expression by in situ hybridization in developing teeth of marine and freshwater fish reveals similar evolved spatial shifts in gene expression. Together, these data support a model in which the polymorphisms within this enhancer underlie evolved tooth gain by shifting the spatial expression of Bmp6 during tooth development, and provide a general strategy to identify spatial differences in enhancer activity in vivo.
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Affiliation(s)
- Mark D Stepaniak
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Tyler A Square
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Craig T Miller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
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21
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Trigila AP, Pisciottano F, Franchini LF. Hearing loss genes reveal patterns of adaptive evolution at the coding and non-coding levels in mammals. BMC Biol 2021; 19:244. [PMID: 34784928 PMCID: PMC8594068 DOI: 10.1186/s12915-021-01170-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 10/21/2021] [Indexed: 11/26/2022] Open
Abstract
Background Mammals possess unique hearing capacities that differ significantly from those of the rest of the amniotes. In order to gain insights into the evolution of the mammalian inner ear, we aim to identify the set of genetic changes and the evolutionary forces that underlie this process. We hypothesize that genes that impair hearing when mutated in humans or in mice (hearing loss (HL) genes) must play important roles in the development and physiology of the inner ear and may have been targets of selective forces across the evolution of mammals. Additionally, we investigated if these HL genes underwent a human-specific evolutionary process that could underlie the evolution of phenotypic traits that characterize human hearing. Results We compiled a dataset of HL genes including non-syndromic deafness genes identified by genetic screenings in humans and mice. We found that many genes including those required for the normal function of the inner ear such as LOXHD1, TMC1, OTOF, CDH23, and PCDH15 show strong signatures of positive selection. We also found numerous noncoding accelerated regions in HL genes, and among them, we identified active transcriptional enhancers through functional enhancer assays in transgenic zebrafish. Conclusions Our results indicate that the key inner ear genes and regulatory regions underwent adaptive evolution in the basal branch of mammals and along the human-specific branch, suggesting that they could have played an important role in the functional remodeling of the cochlea. Altogether, our data suggest that morphological and functional evolution could be attained through molecular changes affecting both coding and noncoding regulatory regions. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01170-6.
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Affiliation(s)
- Anabella P Trigila
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina
| | - Francisco Pisciottano
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina.,Current address: Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina
| | - Lucía F Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1428, Buenos Aires, Argentina.
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22
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Dib A, Zanet J, Mancheno-Ferris A, Gallois M, Markus D, Valenti P, Marques-Prieto S, Plaza S, Kageyama Y, Chanut-Delalande H, Payre F. Pri smORF Peptides Are Wide Mediators of Ecdysone Signaling, Contributing to Shape Spatiotemporal Responses. Front Genet 2021; 12:714152. [PMID: 34527021 DOI: 10.3389/fgene.2021.714152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 07/28/2021] [Indexed: 11/13/2022] Open
Abstract
There is growing evidence that peptides encoded by small open-reading frames (sORF or smORF) can fulfill various cellular functions and define a novel class regulatory molecules. To which extend transcripts encoding only smORF peptides compare with canonical protein-coding genes, yet remain poorly understood. In particular, little is known on whether and how smORF-encoding RNAs might need tightly regulated expression within a given tissue, at a given time during development. We addressed these questions through the analysis of Drosophila polished rice (pri, a.k.a. tarsal less or mille pattes), which encodes four smORF peptides (11-32 amino acids in length) required at several stages of development. Previous work has shown that the expression of pri during epidermal development is regulated in the response to ecdysone, the major steroid hormone in insects. Here, we show that pri transcription is strongly upregulated by ecdysone across a large panel of cell types, suggesting that pri is a core component of ecdysone response. Although pri is produced as an intron-less short transcript (1.5 kb), genetic assays reveal that the developmental functions of pri require an unexpectedly large array of enhancers (spanning over 50 kb), driving a variety of spatiotemporal patterns of pri expression across developing tissues. Furthermore, we found that separate pri enhancers are directly activated by the ecdysone nuclear receptor (EcR) and display distinct regulatory modes between developmental tissues and/or stages. Alike major developmental genes, the expression of pri in a given tissue often involves several enhancers driving apparently redundant (or shadow) expression, while individual pri enhancers can harbor pleiotropic functions across tissues. Taken together, these data reveal the broad role of Pri smORF peptides in ecdysone signaling and show that the cis-regulatory architecture of the pri gene contributes to shape distinct spatial and temporal patterns of ecdysone response throughout development.
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Affiliation(s)
- Azza Dib
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Jennifer Zanet
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Alexandra Mancheno-Ferris
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Maylis Gallois
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Damien Markus
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Philippe Valenti
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Simon Marques-Prieto
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Serge Plaza
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - Yuji Kageyama
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan.,Biosignal Research Center, Kobe University, Kobe, Japan
| | - Hélène Chanut-Delalande
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
| | - François Payre
- Molecular, Cellular and Developmental Biology Department (MCD), Centre de Biologie Intégrative (CBI), CNRS, UPS, University of Toulouse, Toulouse, France
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23
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Sarropoulos I, Sepp M, Frömel R, Leiss K, Trost N, Leushkin E, Okonechnikov K, Joshi P, Giere P, Kutscher LM, Cardoso-Moreira M, Pfister SM, Kaessmann H. Developmental and evolutionary dynamics of cis-regulatory elements in mouse cerebellar cells. Science 2021; 373:eabg4696. [PMID: 34446581 PMCID: PMC7611596 DOI: 10.1126/science.abg4696] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 07/14/2021] [Indexed: 12/13/2022]
Abstract
Organ development is orchestrated by cell- and time-specific gene regulatory networks. In this study, we investigated the regulatory basis of mouse cerebellum development from early neurogenesis to adulthood. By acquiring snATAC-seq (single-nucleus assay for transposase accessible chromatin using sequencing) profiles for ~90,000 cells spanning 11 stages, we mapped cerebellar cell types and identified candidate cis-regulatory elements (CREs). We detected extensive spatiotemporal heterogeneity among progenitor cells and a gradual divergence in the regulatory programs of cerebellar neurons during differentiation. Comparisons to vertebrate genomes and snATAC-seq profiles for ∼20,000 cerebellar cells from the marsupial opossum revealed a shared decrease in CRE conservation during development and differentiation as well as differences in constraint between cell types. Our work delineates the developmental and evolutionary dynamics of gene regulation in cerebellar cells and provides insights into mammalian organ development.
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Affiliation(s)
- Ioannis Sarropoulos
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany.
| | - Mari Sepp
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany.
| | - Robert Frömel
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
| | - Kevin Leiss
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
| | - Nils Trost
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
| | - Evgeny Leushkin
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
| | - Konstantin Okonechnikov
- Hopp Children's Cancer Center (KiTZ) Heidelberg, Division of Pediatric Neurooncology, German Cancer Consortium (DKTK), and German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Piyush Joshi
- Hopp Children's Cancer Center (KiTZ) Heidelberg, Division of Pediatric Neurooncology, German Cancer Consortium (DKTK), and German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Peter Giere
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - Lena M Kutscher
- Hopp Children's Cancer Center (KiTZ) Heidelberg, Developmental Origins of Pediatric Cancer Group, German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| | - Margarida Cardoso-Moreira
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany
- Evolutionary Developmental Biology Laboratory, Francis Crick Institute, London NW1 1AT, UK
| | - Stefan M Pfister
- Hopp Children's Cancer Center (KiTZ) Heidelberg, Division of Pediatric Neurooncology, German Cancer Consortium (DKTK), and German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany.
- Department of Pediatric Hematology and Oncology, Heidelberg University Hospital, Heidelberg, Germany
| | - Henrik Kaessmann
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, D-69120 Heidelberg, Germany.
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24
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Singh D, Yi SV. Enhancer pleiotropy, gene expression, and the architecture of human enhancer-gene interactions. Mol Biol Evol 2021; 38:3898-3909. [PMID: 33749795 PMCID: PMC8383896 DOI: 10.1093/molbev/msab085] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 02/10/2021] [Accepted: 03/18/2021] [Indexed: 12/30/2022] Open
Abstract
Enhancers are often studied as noncoding regulatory elements that modulate the precise spatiotemporal expression of genes in a highly tissue-specific manner. This paradigm has been challenged by recent evidence of individual enhancers acting in multiple tissues or developmental contexts. However, the frequency of these enhancers with high degrees of “pleiotropy” out of all putative enhancers is not well understood. Consequently, it is unclear how the variation of enhancer pleiotropy corresponds to the variation in expression breadth of target genes. Here, we use multi-tissue chromatin maps from diverse human tissues to investigate the enhancer–gene interaction architecture while accounting for 1) the distribution of enhancer pleiotropy, 2) the variations of regulatory links from enhancers to target genes, and 3) the expression breadth of target genes. We show that most enhancers are tissue-specific and that highly pleiotropy enhancers account for <1% of all putative regulatory sequences in the human genome. Notably, several genomic features are indicative of increasing enhancer pleiotropy, including longer sequence length, greater number of links to genes, increasing abundance and diversity of encoded transcription factor motifs, and stronger evolutionary conservation. Intriguingly, the number of enhancers per gene remains remarkably consistent for all genes (∼14). However, enhancer pleiotropy does not directly translate to the expression breadth of target genes. We further present a series of Gaussian Mixture Models to represent this organization architecture. Consequently, we demonstrate that a modest trend of more pleiotropic enhancers targeting more broadly expressed genes can generate the observed diversity of expression breadths in the human genome.
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Affiliation(s)
- Devika Singh
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Soojin V Yi
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
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25
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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: 0] [Impact Index Per Article: 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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26
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Uesaka M, Kuratani S, Irie N. The developmental hourglass model and recapitulation: An attempt to integrate the two models. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2021; 338:76-86. [PMID: 33503326 PMCID: PMC9292893 DOI: 10.1002/jez.b.23027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 01/03/2021] [Accepted: 01/04/2021] [Indexed: 12/18/2022]
Abstract
Recapitulation is a hypothetical concept that assumes embryogenesis of an animal parallels its own phylogenetic history, sequentially developing from more ancestral features to more derived ones. This concept predicts that the earliest developmental stage of various animals should represent the most evolutionarily conserved patterns. Recent transcriptome‐based studies, on the other hand, have reported that mid‐embryonic, organogenetic periods show the highest level of conservation (the developmental hourglass model). This, however, does not rule out the possibility that recapitulation would still be detected after the mid‐embryonic period. In accordance with this, recapitulation‐like morphological features are enriched in late developmental stages. Moreover, our recent chromatin accessibility‐based study provided molecular evidence for recapitulation in the mid‐to‐late embryogenesis of vertebrates, as newly evolved gene regulatory elements tended to be activated at late embryonic stages. In this review, we revisit the recapitulation hypothesis, together with recent molecular‐based studies that support the developmental hourglass model. We contend that the recapitulation hypothesis does not entirely contradict the developmental hourglass model and that these two may even coexist in later embryonic stages of vertebrates. Finally, we review possible mechanisms underlying the recapitulation pattern of chromatin accessibility together with the hourglass‐like evolutionary conservation in vertebrate embryogenesis. Recapitulation pattern has been reported for chromatin accessibility during the mid‐to‐late embryogenesis. The observed recapitulation pattern and the developmental hourglass model may coexist. The possible evolutionary mechanisms underlying tendencies of embryonic evolution were discussed.
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Affiliation(s)
- Masahiro Uesaka
- Laboratory for Evolutionary Morphology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
| | - Shigeru Kuratani
- Laboratory for Evolutionary Morphology, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan.,Laboratory for Evolutionary Morphology, RIKEN Cluster for Pioneering Research, Kobe, Japan
| | - Naoki Irie
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.,Universal Biology Institute, The University of Tokyo, Tokyo, Japan
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27
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Hatleberg WL, Hinman VF. Modularity and hierarchy in biological systems: Using gene regulatory networks to understand evolutionary change. Curr Top Dev Biol 2021; 141:39-73. [DOI: 10.1016/bs.ctdb.2020.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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28
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Soverna AF, Rodriguez NC, Korgaonkar A, Hasson E, Stern DL, Frankel N. Cis-regulatory variation in the shavenbaby gene underlies intraspecific phenotypic variation, mirroring interspecific divergence in the same trait. Evolution 2020; 75:427-436. [PMID: 33314059 DOI: 10.1111/evo.14142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/20/2020] [Accepted: 11/24/2020] [Indexed: 12/14/2022]
Abstract
Despite considerable progress in recent decades in dissecting the genetic causes of natural morphological variation, there is limited understanding of how variation within species ultimately contributes to species differences. We have studied patterning of the non-sensory hairs, commonly known as "trichomes," on the dorsal cuticle of first-instar larvae of Drosophila. Most Drosophila species produce a dense lawn of dorsal trichomes, but a subset of these trichomes were lost in D. sechellia and D. ezoana due entirely to regulatory evolution of the shavenbaby (svb) gene. Here, we describe intraspecific variation in dorsal trichome patterns of first-instar larvae of D. virilis that is similar to the trichome pattern variation identified previously between species. We found that a single large effect QTL, which includes svb, explains most of the trichome number difference between two D. virilis strains and that svb expression correlates with the trichome difference between strains. This QTL does not explain the entire difference between strains, implying that additional loci contribute to variation in trichome numbers. Thus, the genetic architecture of intraspecific variation exhibits similarities and differences with interspecific variation that may reflect differences in long-term and short-term evolutionary processes.
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Affiliation(s)
- Ana Faigon Soverna
- Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA, CONICET-UBA), Buenos Aires, 1417, Argentina
| | - Nahuel Cabrera Rodriguez
- Departamento de Ecología, Genética y Evolución (FCEyN, UBA) and Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA, CONICET-UBA), Buenos Aires, 1428, Argentina
| | - Aishwarya Korgaonkar
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Esteban Hasson
- Departamento de Ecología, Genética y Evolución (FCEyN, UBA) and Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA, CONICET-UBA), Buenos Aires, 1428, Argentina
| | - David L Stern
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, VA, 20147, USA
| | - Nicolás Frankel
- Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE, CONICET-UBA) and Departamento de Ecología, Genética y Evolución (FCEyN, UBA), Buenos Aires, 1428, Argentina
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29
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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: 111] [Impact Index Per Article: 27.8] [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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30
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Karakose E, Wang H, Inabnet W, Thakker RV, Libutti S, Fernandez-Ranvier G, Suh H, Stevenson M, Kinoshita Y, Donovan M, Antipin Y, Li Y, Liu X, Jin F, Wang P, Uzilov A, Argmann C, Schadt EE, Stewart AF, Scott DK, Lambertini L. Aberrant methylation underlies insulin gene expression in human insulinoma. Nat Commun 2020; 11:5210. [PMID: 33060578 PMCID: PMC7566641 DOI: 10.1038/s41467-020-18839-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 09/16/2020] [Indexed: 12/23/2022] Open
Abstract
Human insulinomas are rare, benign, slowly proliferating, insulin-producing beta cell tumors that provide a molecular "recipe" or "roadmap" for pathways that control human beta cell regeneration. An earlier study revealed abnormal methylation in the imprinted p15.5-p15.4 region of chromosome 11, known to be abnormally methylated in another disorder of expanded beta cell mass and function: the focal variant of congenital hyperinsulinism. Here, we compare deep DNA methylome sequencing on 19 human insulinomas, and five sets of normal beta cells. We find a remarkably consistent, abnormal methylation pattern in insulinomas. The findings suggest that abnormal insulin (INS) promoter methylation and altered transcription factor expression create alternative drivers of INS expression, replacing canonical PDX1-driven beta cell specification with a pathological, looping, distal enhancer-based form of transcriptional regulation. Finally, NFaT transcription factors, rather than the canonical PDX1 enhancer complex, are predicted to drive INS transactivation.
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Affiliation(s)
- Esra Karakose
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | | | - William Inabnet
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Rajesh V Thakker
- The Academic Endocrine Unit, University of Oxford, OX3 7LJ, Oxford, UK
| | - Steven Libutti
- The Cancer Institute of New Jersey, New Brunswick, NJ, 08901, USA
| | - Gustavo Fernandez-Ranvier
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Hyunsuk Suh
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Mark Stevenson
- The Academic Endocrine Unit, University of Oxford, OX3 7LJ, Oxford, UK
| | - Yayoi Kinoshita
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Michael Donovan
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Yevgeniy Antipin
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Sema4, Stamford, CT, 06902, USA
| | - Yan Li
- The Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Xiaoxiao Liu
- The Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Fulai Jin
- The Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Peng Wang
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Andrew Uzilov
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Sema4, Stamford, CT, 06902, USA
| | - Carmen Argmann
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Eric E Schadt
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Sema4, Stamford, CT, 06902, USA
| | - Andrew F Stewart
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
| | - Donald K Scott
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Luca Lambertini
- From the Diabetes Obesity and Metabolism Institute, The Department of Surgery, The Department of Pathology, The Department of Genetics and Genomics Sciences and The Institute for Genomics and Multiscale Biology, The Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
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31
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Fuqua T, Jordan J, van Breugel ME, Halavatyi A, Tischer C, Polidoro P, Abe N, Tsai A, Mann RS, Stern DL, Crocker J. Dense and pleiotropic regulatory information in a developmental enhancer. Nature 2020; 587:235-239. [PMID: 33057197 DOI: 10.1038/s41586-020-2816-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 07/22/2020] [Indexed: 01/08/2023]
Abstract
Changes in gene regulation underlie much of phenotypic evolution1. However, our understanding of the potential for regulatory evolution is biased, because most evidence comes from either natural variation or limited experimental perturbations2. Using an automated robotics pipeline, we surveyed an unbiased mutation library for a developmental enhancer in Drosophila melanogaster. We found that almost all mutations altered gene expression and that parameters of gene expression-levels, location, and state-were convolved. The widespread pleiotropic effects of most mutations may constrain the evolvability of developmental enhancers. Consistent with these observations, comparisons of diverse Drosophila larvae revealed apparent biases in the phenotypes influenced by the enhancer. Developmental enhancers may encode a higher density of regulatory information than has been appreciated previously, imposing constraints on regulatory evolution.
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Affiliation(s)
- Timothy Fuqua
- European Molecular Biology Laboratory, Heidelberg, Germany.,Joint PhD Collaboration, EMBL and Faculty of Biosciences Heidelberg University, Heidelberg, Germany
| | | | | | | | | | | | - Namiko Abe
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Albert Tsai
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Richard S Mann
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | | | - Justin Crocker
- European Molecular Biology Laboratory, Heidelberg, Germany.
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32
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A Mutation in the Drosophila melanogaster eve Stripe 2 Minimal Enhancer Is Buffered by Flanking Sequences. G3 (BETHESDA, MD.) 2020; 10:4473-4482. [PMID: 33037064 PMCID: PMC7718739 DOI: 10.1534/g3.120.401777] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Enhancers are DNA sequences composed of transcription factor binding sites that drive complex patterns of gene expression in space and time. Until recently, studying enhancers in their genomic context was technically challenging. Therefore, minimal enhancers, the shortest pieces of DNA that can drive an expression pattern that resembles a gene's endogenous pattern, are often used to study features of enhancer function. However, evidence suggests that some enhancers require sequences outside the minimal enhancer to maintain function under environmental perturbations. We hypothesized that these additional sequences also prevent misexpression caused by a transcription factor binding site mutation within a minimal enhancer. Using the Drosophila melanogastereven-skipped stripe 2 enhancer as a case study, we tested the effect of a Giant binding site mutation (gt-2) on the expression patterns driven by minimal and extended enhancer reporter constructs. We found that, in contrast to the misexpression caused by the gt-2 binding site deletion in the minimal enhancer, the same gt-2 binding site deletion in the extended enhancer did not have an effect on expression. The buffering of expression levels, but not expression pattern, is partially explained by an additional Giant binding site outside the minimal enhancer. Deleting the gt-2 binding site in the endogenous locus had no significant effect on stripe 2 expression. Our results indicate that rules derived from mutating enhancer reporter constructs may not represent what occurs in the endogenous context.
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33
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Li Y, Osuma A, Correa E, Okebalama MA, Dao P, Gaylord O, Aburas J, Islam P, Brown AE, Kratsios P. Establishment and maintenance of motor neuron identity via temporal modularity in terminal selector function. eLife 2020; 9:59464. [PMID: 33001031 PMCID: PMC7529460 DOI: 10.7554/elife.59464] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/20/2020] [Indexed: 02/06/2023] Open
Abstract
Terminal selectors are transcription factors (TFs) that establish during development and maintain throughout life post-mitotic neuronal identity. We previously showed that UNC-3/Ebf, the terminal selector of C. elegans cholinergic motor neurons (MNs), acts indirectly to prevent alternative neuronal identities (Feng et al., 2020). Here, we globally identify the direct targets of UNC-3. Unexpectedly, we find that the suite of UNC-3 targets in MNs is modified across different life stages, revealing ‘temporal modularity’ in terminal selector function. In all larval and adult stages examined, UNC-3 is required for continuous expression of various protein classes (e.g. receptors, transporters) critical for MN function. However, only in late larvae and adults, UNC-3 is required to maintain expression of MN-specific TFs. Minimal disruption of UNC-3’s temporal modularity via genome engineering affects locomotion. Another C. elegans terminal selector (UNC-30/Pitx) also exhibits temporal modularity, supporting the potential generality of this mechanism for the control of neuronal identity.
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Affiliation(s)
- Yinan Li
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States
| | - Anthony Osuma
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States
| | - Edgar Correa
- Department of Neurobiology, University of Chicago, Chicago, United States.,Cell and Molecular Biology Program, University of Chicago, Chicago, United States
| | | | - Pauline Dao
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Olivia Gaylord
- Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States
| | - Jihad Aburas
- Department of Neurobiology, University of Chicago, Chicago, United States
| | - Priota Islam
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - André Ex Brown
- MRC London Institute of Medical Sciences, London, United Kingdom.,Institute of Clinical Sciences, Imperial College London, London, United Kingdom
| | - Paschalis Kratsios
- Department of Neurobiology, University of Chicago, Chicago, United States.,Committee on Neurobiology, University of Chicago, Chicago, United States.,Cell and Molecular Biology Program, University of Chicago, Chicago, United States.,Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, Chicago, United States.,The Grossman Institute for Neuroscience, Quantitative Biology, and Human Behavior, University of Chicago, Chicago, United States
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34
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Lewis JJ, Van Belleghem SM. Mechanisms of Change: A Population-Based Perspective on the Roles of Modularity and Pleiotropy in Diversification. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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35
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Abstract
Form diversity is fueled by changes in the expression of genes that build organisms. New expression often results from the emergence of new DNA switches, known as transcriptional enhancers. Many enhancers are thought to appear through the recycling of older enhancers, a process called evolutionary co-option. Enhancer co-option is difficult to assess, and the molecular mechanisms explaining its prevalence are elusive. Using state-of-the-art quantification and analyses, we reveal that the sequences of an ancestral and a derived enhancer overlap extensively. They contain specific binding sites for regulators imparting spatial activities. We found that the two enhancers also share a site facilitating access to chromatin in a region where they overlap. The diversity of forms in multicellular organisms originates largely from the spatial redeployment of developmental genes [S. B. Carroll, Cell 134, 25–36 (2008)]. Several scenarios can explain the emergence of cis-regulatory elements that govern novel aspects of a gene expression pattern [M. Rebeiz, M. Tsiantis, Curr. Opin. Genet. Dev. 45, 115–123 (2017)]. One scenario, enhancer co-option, holds that a DNA sequence producing an ancestral regulatory activity also becomes the template for a new regulatory activity, sharing regulatory information. While enhancer co-option might fuel morphological diversification, it has rarely been documented [W. J. Glassford et al., Dev. Cell 34, 520–531 (2015)]. Moreover, if two regulatory activities are borne from the same sequence, their modularity, considered a defining feature of enhancers [J. Banerji, L. Olson, W. Schaffner, Cell 33, 729–740 (1983)], might be affected by pleiotropy. Sequence overlap may thereby play a determinant role in enhancer function and evolution. Here, we investigated this problem with two regulatory activities of the Drosophila gene yellow, the novel spot enhancer and the ancestral wing blade enhancer. We used precise and comprehensive quantification of each activity in Drosophila wings to systematically map their sequences along the locus. We show that the spot enhancer has co-opted the sequences of the wing blade enhancer. We also identified a pleiotropic site necessary for DNA accessibility of a shared regulatory region. While the evolutionary steps leading to the derived activity are still unknown, such pleiotropy suggests that enhancer accessibility could be one of the molecular mechanisms seeding evolutionary co-option.
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36
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Archambeault SL, Bärtschi LR, Merminod AD, Peichel CL. Adaptation via pleiotropy and linkage: Association mapping reveals a complex genetic architecture within the stickleback Eda locus. Evol Lett 2020; 4:282-301. [PMID: 32774879 PMCID: PMC7403726 DOI: 10.1002/evl3.175] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/04/2020] [Accepted: 04/29/2020] [Indexed: 11/26/2022] Open
Abstract
Genomic mapping of the loci associated with phenotypic evolution has revealed genomic "hotspots," or regions of the genome that control multiple phenotypic traits. This clustering of loci has important implications for the speed and maintenance of adaptation and could be due to pleiotropic effects of a single mutation or tight genetic linkage of multiple causative mutations affecting different traits. The threespine stickleback (Gasterosteus aculeatus) is a powerful model for the study of adaptive evolution because the marine ecotype has repeatedly adapted to freshwater environments across the northern hemisphere in the last 12,000 years. Freshwater ecotypes have repeatedly fixed a 16 kilobase haplotype on chromosome IV that contains Ectodysplasin (Eda), a gene known to affect multiple traits, including defensive armor plates, lateral line sensory hair cells, and schooling behavior. Many additional traits have previously been mapped to a larger region of chromosome IV that encompasses the Eda freshwater haplotype. To identify which of these traits specifically map to this adaptive haplotype, we made crosses of rare marine fish heterozygous for the freshwater haplotype in an otherwise marine genetic background. Further, we performed fine-scale association mapping in a fully interbreeding, polymorphic population of freshwater stickleback to disentangle the effects of pleiotropy and linkage on the phenotypes affected by this haplotype. Although we find evidence that linked mutations have small effects on a few phenotypes, a small 1.4-kb region within the first intron of Eda has large effects on three phenotypic traits: lateral plate count, and both the number and patterning of the posterior lateral line neuromasts. Thus, the Eda haplotype is a hotspot of adaptation in stickleback due to both a small, pleiotropic region affecting multiple traits as well as multiple linked mutations affecting additional traits.
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Affiliation(s)
- Sophie L. Archambeault
- Institute of Ecology and EvolutionUniversity of BernBern3012Switzerland
- Graduate Program in Molecular and Cellular BiologyUniversity of WashingtonSeattleWashington98195
- Divisions of Basic Sciences and Human BiologyFred Hutchinson Cancer Research CenterSeattleWashington98109
| | - Luis R. Bärtschi
- Institute of Ecology and EvolutionUniversity of BernBern3012Switzerland
| | | | - Catherine L. Peichel
- Institute of Ecology and EvolutionUniversity of BernBern3012Switzerland
- Graduate Program in Molecular and Cellular BiologyUniversity of WashingtonSeattleWashington98195
- Divisions of Basic Sciences and Human BiologyFred Hutchinson Cancer Research CenterSeattleWashington98109
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37
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Rohner PT. Evolution of multivariate wing allometry in schizophoran flies (Diptera: Schizophora). J Evol Biol 2020; 33:831-841. [PMID: 32145126 PMCID: PMC7318208 DOI: 10.1111/jeb.13613] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 01/12/2023]
Abstract
The proximate and ultimate mechanisms underlying scaling relationships as well as their evolutionary consequences remain an enigmatic issue in evolutionary biology. Here, I investigate the evolution of wing allometries in the Schizophora, a group of higher Diptera that radiated about 65 million years ago, by studying static allometries in five species using multivariate approaches. Despite the vast ecological diversity observed in contemporary members of the Schizophora and independent evolutionary histories throughout most of the Cenozoic, size-related changes represent a major contributor to overall variation in wing shape, both within and among species. Static allometries differ between species and sexes, yet multivariate allometries are correlated across species, suggesting a shared developmental programme underlying size-dependent phenotypic plasticity. Static allometries within species also correlate with evolutionary divergence across 33 different families (belonging to 11 of 13 superfamilies) of the Schizophora. This again points towards a general developmental, genetic or evolutionary mechanism that canalizes or maintains the covariation between shape and size in spite of rapid ecological and morphological diversification during the Cenozoic. I discuss the putative roles of developmental constraints and natural selection in the evolution of wing allometry in the Schizophora.
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38
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Modular Organization of Cis-regulatory Control Information of Neurotransmitter Pathway Genes in Caenorhabditis elegans. Genetics 2020; 215:665-681. [PMID: 32444379 DOI: 10.1534/genetics.120.303206] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/20/2020] [Indexed: 11/18/2022] Open
Abstract
We explore here the cis-regulatory logic that dictates gene expression in specific cell types in the nervous system. We focus on a set of eight genes involved in the synthesis, transport, and breakdown of three neurotransmitter systems: acetylcholine (unc-17 /VAChT, cha-1 /ChAT, cho-1 /ChT, and ace-2 /AChE), glutamate (eat-4 /VGluT), and γ-aminobutyric acid (unc-25 /GAD, unc-46 /LAMP, and unc-47 /VGAT). These genes are specifically expressed in defined subsets of cells in the nervous system. Through transgenic reporter gene assays, we find that the cellular specificity of expression of all of these genes is controlled in a modular manner through distinct cis-regulatory elements, corroborating the previously inferred piecemeal nature of specification of neurotransmitter identity. This modularity provides the mechanistic basis for the phenomenon of "phenotypic convergence," in which distinct regulatory pathways can generate similar phenotypic outcomes (i.e., the acquisition of a specific neurotransmitter identity) in different neuron classes. We also identify cases of enhancer pleiotropy, in which the same cis-regulatory element is utilized to control gene expression in distinct neuron types. We engineered a cis-regulatory allele of the vesicular acetylcholine transporter, unc-17 /VAChT, to assess the functional contribution of a "shadowed" enhancer. We observed a selective loss of unc-17 /VAChT expression in one cholinergic pharyngeal pacemaker motor neuron class and a behavioral phenotype that matches microsurgical removal of this neuron. Our analysis illustrates the value of understanding cis-regulatory information to manipulate gene expression and control animal behavior.
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On the specificity of gene regulatory networks: How does network co-option affect subsequent evolution? Curr Top Dev Biol 2020; 139:375-405. [PMID: 32450967 DOI: 10.1016/bs.ctdb.2020.03.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The process of multicellular organismal development hinges upon the specificity of developmental programs: for different parts of the organism to form unique features, processes must exist to specify each part. This specificity is thought to be hardwired into gene regulatory networks, which activate cohorts of genes in particular tissues at particular times during development. However, the evolution of gene regulatory networks sometimes occurs by mechanisms that sacrifice specificity. One such mechanism is network co-option, in which existing gene networks are redeployed in new developmental contexts. While network co-option may offer an efficient mechanism for generating novel phenotypes, losses of tissue specificity at redeployed network genes could restrict the ability of the affected traits to evolve independently. At present, there has not been a detailed discussion regarding how tissue specificity of network genes might be altered due to gene network co-option at its initiation, as well as how trait independence can be retained or restored after network co-option. A lack of clarity about network co-option makes it more difficult to speculate on the long-term evolutionary implications of this mechanism. In this review, we will discuss the possible initial outcomes of network co-option, outline the mechanisms by which networks may retain or subsequently regain specificity after network co-option, and comment on some of the possible evolutionary consequences of network co-option. We place special emphasis on the need to consider selectively-neutral outcomes of network co-option to improve our understanding of the role of this mechanism in trait evolution.
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Erwin DH. The origin of animal body plans: a view from fossil evidence and the regulatory genome. Development 2020; 147:147/4/dev182899. [DOI: 10.1242/dev.182899] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ABSTRACT
The origins and the early evolution of multicellular animals required the exploitation of holozoan genomic regulatory elements and the acquisition of new regulatory tools. Comparative studies of metazoans and their relatives now allow reconstruction of the evolution of the metazoan regulatory genome, but the deep conservation of many genes has led to varied hypotheses about the morphology of early animals and the extent of developmental co-option. In this Review, I assess the emerging view that the early diversification of animals involved small organisms with diverse cell types, but largely lacking complex developmental patterning, which evolved independently in different bilaterian clades during the Cambrian Explosion.
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Affiliation(s)
- Douglas H. Erwin
- Department of Paleobiology, MRC-121, National Museum of Natural History, PO Box 37012, Washington, DC 20013-7012, USA
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
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Silencers, Enhancers, and the Multifunctional Regulatory Genome. Trends Genet 2020; 36:149-151. [PMID: 31918861 DOI: 10.1016/j.tig.2019.12.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 12/10/2019] [Indexed: 11/22/2022]
Abstract
Negative regulation of gene expression by transcriptional silencers has been difficult to study due to limited defined examples. A new study by Gisselbrecht et al. has dramatically increased the number of identified silencers and reveals that they are bifunctional regulatory sequences that also act as gene expression-promoting enhancers.
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An Atlas of Transcription Factors Expressed in Male Pupal Terminalia of Drosophila melanogaster. G3-GENES GENOMES GENETICS 2019; 9:3961-3972. [PMID: 31619460 PMCID: PMC6893207 DOI: 10.1534/g3.119.400788] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During development, transcription factors and signaling molecules govern gene regulatory networks to direct the formation of unique morphologies. As changes in gene regulatory networks are often implicated in morphological evolution, mapping transcription factor landscapes is important, especially in tissues that undergo rapid evolutionary change. The terminalia (genital and anal structures) of Drosophila melanogaster and its close relatives exhibit dramatic changes in morphology between species. While previous studies have identified network components important for patterning the larval genital disc, the networks governing adult structures during pupal development have remained uncharted. Here, we performed RNA-seq in whole Drosophila melanogaster male terminalia followed by in situ hybridization for 100 highly expressed transcription factors during pupal development. We find that the male terminalia are highly patterned during pupal stages and that specific transcription factors mark separate structures and substructures. Our results are housed online in a searchable database (https://flyterminalia.pitt.edu/) as a resource for the community. This work lays a foundation for future investigations into the gene regulatory networks governing the development and evolution of Drosophila terminalia.
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Parallel evolution of ancient, pleiotropic enhancers underlies butterfly wing pattern mimicry. Proc Natl Acad Sci U S A 2019; 116:24174-24183. [PMID: 31712408 DOI: 10.1073/pnas.1907068116] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Color pattern mimicry in Heliconius butterflies is a classic case study of complex trait adaptation via selection on a few large effect genes. Association studies have linked color pattern variation to a handful of noncoding regions, yet the presumptive cis-regulatory elements (CREs) that control color patterning remain unknown. Here we combine chromatin assays, DNA sequence associations, and genome editing to functionally characterize 5 cis-regulatory elements of the color pattern gene optix We were surprised to find that the cis-regulatory architecture of optix is characterized by pleiotropy and regulatory fragility, where deletion of individual cis-regulatory elements has broad effects on both color pattern and wing vein development. Remarkably, we found orthologous cis-regulatory elements associate with wing pattern convergence of distantly related comimics, suggesting that parallel coevolution of ancestral elements facilitated pattern mimicry. Our results support a model of color pattern evolution in Heliconius where changes to ancient, multifunctional cis-regulatory elements underlie adaptive radiation.
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Gegenhuber B, Tollkuhn J. Sex Differences in the Epigenome: A Cause or Consequence of Sexual Differentiation of the Brain? Genes (Basel) 2019; 10:genes10060432. [PMID: 31181654 PMCID: PMC6627918 DOI: 10.3390/genes10060432] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 05/29/2019] [Accepted: 06/03/2019] [Indexed: 12/19/2022] Open
Abstract
Females and males display differences in neural activity patterns, behavioral responses, and incidence of psychiatric and neurological diseases. Sex differences in the brain appear throughout the animal kingdom and are largely a consequence of the physiological requirements necessary for the distinct roles of the two sexes in reproduction. As with the rest of the body, gonadal steroid hormones act to specify and regulate many of these differences. It is thought that transient hormonal signaling during brain development gives rise to persistent sex differences in gene expression via an epigenetic mechanism, leading to divergent neurodevelopmental trajectories that may underlie sex differences in disease susceptibility. However, few genes with a persistent sex difference in expression have been identified, and only a handful of studies have employed genome-wide approaches to assess sex differences in epigenomic modifications. To date, there are no confirmed examples of gene regulatory elements that direct sex differences in gene expression in the brain. Here, we review foundational studies in this field, describe transcriptional mechanisms that could act downstream of hormone receptors in the brain, and suggest future approaches for identification and validation of sex-typical gene programs. We propose that sexual differentiation of the brain involves self-perpetuating transcriptional states that canalize sex-specific development.
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Affiliation(s)
- Bruno Gegenhuber
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
- Watson School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
| | - Jessica Tollkuhn
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
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