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Fan C, Xing X, Murphy SJH, Poursine-Laurent J, Schmidt H, Parikh BA, Yoon J, Choudhary MNK, Saligrama N, Piersma SJ, Yokoyama WM, Wang T. Cis-regulatory evolution of the recently expanded Ly49 gene family. Nat Commun 2024; 15:4839. [PMID: 38844462 PMCID: PMC11156856 DOI: 10.1038/s41467-024-48990-y] [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: 11/13/2023] [Accepted: 05/14/2024] [Indexed: 06/09/2024] Open
Abstract
Comparative genomics has revealed the rapid expansion of multiple gene families involved in immunity. Members within each gene family often evolved distinct roles in immunity. However, less is known about the evolution of their epigenome and cis-regulation. Here we systematically profile the epigenome of the recently expanded murine Ly49 gene family that mainly encode either inhibitory or activating surface receptors on natural killer cells. We identify a set of cis-regulatory elements (CREs) for activating Ly49 genes. In addition, we show that in mice, inhibitory and activating Ly49 genes are regulated by two separate sets of proximal CREs, likely resulting from lineage-specific losses of CRE activity. Furthermore, we find that some Ly49 genes are cross-regulated by the CREs of other Ly49 genes, suggesting that the Ly49 family has begun to evolve a concerted cis-regulatory mechanism. Collectively, we demonstrate the different modes of cis-regulatory evolution for a rapidly expanding gene family.
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Affiliation(s)
- Changxu Fan
- Department of Genetics, Washington University School of Medicine, St. Louis, 63110, USA
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, St. Louis, 63110, USA
| | - Xiaoyun Xing
- Department of Genetics, Washington University School of Medicine, St. Louis, 63110, USA
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, St. Louis, 63110, USA
| | - Samuel J H Murphy
- Department of Neurology, Washington University School of Medicine, St. Louis, 63110, USA
- Medical Scientist Training Program, Washington University School of Medicine, St. Louis, 63110, USA
| | - Jennifer Poursine-Laurent
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, 63110, USA
| | - Heather Schmidt
- Department of Genetics, Washington University School of Medicine, St. Louis, 63110, USA
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, St. Louis, 63110, USA
| | - Bijal A Parikh
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, 63110, USA
| | - Jeesang Yoon
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, 63110, USA
| | - Mayank N K Choudhary
- Department of Genetics, Washington University School of Medicine, St. Louis, 63110, USA
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, St. Louis, 63110, USA
| | - Naresha Saligrama
- Department of Neurology, Washington University School of Medicine, St. Louis, 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, 63110, USA
- Bursky Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, 63110, USA
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, 63110, USA
- Center for Brain Immunology and Glia (BIG), Washington University School of Medicine, St. Louis, 63110, USA
| | - Sytse J Piersma
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, 63110, USA.
- Siteman Cancer Center, Washington University School of Medicine, St. Louis, 63110, USA.
| | - Wayne M Yokoyama
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, 63110, USA.
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, 63110, USA.
| | - Ting Wang
- Department of Genetics, Washington University School of Medicine, St. Louis, 63110, USA.
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, St. Louis, 63110, USA.
- McDonnell Genome Institute, Washington University School of Medicine, St. Louis, 63110, USA.
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Kaucka M. Cis-regulatory landscapes in the evolution and development of the mammalian skull. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220079. [PMID: 37183897 PMCID: PMC10184250 DOI: 10.1098/rstb.2022.0079] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
Extensive morphological variation found in mammals reflects the wide spectrum of their ecological adaptations. The highest morphological diversity is present in the craniofacial region, where geometry is mainly dictated by the bony skull. Mammalian craniofacial development represents complex multistep processes governed by numerous conserved genes that require precise spatio-temporal control. A central question in contemporary evolutionary biology is how a defined set of conserved genes can orchestrate formation of fundamentally different structures, and therefore how morphological variability arises. In principle, differential gene expression patterns during development are the source of morphological variation. With the emergence of multicellular organisms, precise regulation of gene expression in time and space is attributed to cis-regulatory elements. These elements contribute to higher-order chromatin structure and together with trans-acting factors control transcriptional landscapes that underlie intricate morphogenetic processes. Consequently, divergence in cis-regulation is believed to rewire existing gene regulatory networks and form the core of morphological evolution. This review outlines the fundamental principles of the genetic code and genomic regulation interplay during development. Recent work that deepened our comprehension of cis-regulatory element origin, divergence and function is presented here to illustrate the state-of-the-art research that uncovered the principles of morphological novelty. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
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Affiliation(s)
- Marketa Kaucka
- Max Planck Institute for Evolutionary Biology, Plön 24306, Germany
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Pereira J, Johnson WE, O’Brien SJ, Jarvis ED, Zhang G, Gilbert MTP, Vasconcelos V, Antunes A. Evolutionary genomics and adaptive evolution of the Hedgehog gene family (Shh, Ihh and Dhh) in vertebrates. PLoS One 2014; 9:e74132. [PMID: 25549322 PMCID: PMC4280113 DOI: 10.1371/journal.pone.0074132] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 07/29/2013] [Indexed: 12/21/2022] Open
Abstract
The Hedgehog (Hh) gene family codes for a class of secreted proteins composed of two active domains that act as signalling molecules during embryo development, namely for the development of the nervous and skeletal systems and the formation of the testis cord. While only one Hh gene is found typically in invertebrate genomes, most vertebrates species have three (Sonic hedgehog – Shh; Indian hedgehog – Ihh; and Desert hedgehog – Dhh), each with different expression patterns and functions, which likely helped promote the increasing complexity of vertebrates and their successful diversification. In this study, we used comparative genomic and adaptive evolutionary analyses to characterize the evolution of the Hh genes in vertebrates following the two major whole genome duplication (WGD) events. To overcome the lack of Hh-coding sequences on avian publicly available databases, we used an extensive dataset of 45 avian and three non-avian reptilian genomes to show that birds have all three Hh paralogs. We find suggestions that following the WGD events, vertebrate Hh paralogous genes evolved independently within similar linkage groups and under different evolutionary rates, especially within the catalytic domain. The structural regions around the ion-binding site were identified to be under positive selection in the signaling domain. These findings contrast with those observed in invertebrates, where different lineages that experienced gene duplication retained similar selective constraints in the Hh orthologs. Our results provide new insights on the evolutionary history of the Hh gene family, the functional roles of these paralogs in vertebrate species, and on the location of mutational hotspots.
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Affiliation(s)
- Joana Pereira
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal
| | - Warren E. Johnson
- Smithsonian Conservation Biology Institute, National Zoological Park, Front Royal, Virginia, United States of America
| | - Stephen J. O’Brien
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, St. Petersburg, Russia
- Oceanographic Center, N. Ocean Drive, Nova Southeastern University, Ft. Lauderdale, Florida, United States of America
| | - Erich D. Jarvis
- Howard Hughes Medical Institute, Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Guojie Zhang
- BGI-Shenzhen, Beishan Industrial Zoon, Yantian District, Shenzhen, China
| | - M. Thomas P. Gilbert
- Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
| | - Vitor Vasconcelos
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal
- Department of Biology, Faculty of Sciences, University of Porto, Porto, Portugal
| | - Agostinho Antunes
- CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal
- Department of Biology, Faculty of Sciences, University of Porto, Porto, Portugal
- * E-mail:
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Roberts JA, Miguel-Escalada I, Slovik KJ, Walsh KT, Hadzhiev Y, Sanges R, Stupka E, Marsh EK, Balciuniene J, Balciunas D, Müller F. Targeted transgene integration overcomes variability of position effects in zebrafish. Development 2014; 141:715-24. [PMID: 24449846 DOI: 10.1242/dev.100347] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Zebrafish transgenesis is increasingly popular owing to the optical transparency and external development of embryos, which provide a scalable vertebrate model for in vivo experimentation. The ability to express transgenes in a tightly controlled spatio-temporal pattern is an important prerequisite for exploitation of zebrafish in a wide range of biomedical applications. However, conventional transgenesis methods are plagued by position effects: the regulatory environment of genomic integration sites leads to variation of expression patterns of transgenes driven by engineered cis-regulatory modules. This limitation represents a bottleneck when studying the precise function of cis-regulatory modules and their subtle variants or when various effector proteins are to be expressed for labelling and manipulation of defined sets of cells. Here, we provide evidence for the efficient elimination of variability of position effects by developing a PhiC31 integrase-based targeting method. To detect targeted integration events, a simple phenotype scoring of colour change in the lens of larvae is used. We compared PhiC31-based integration and Tol2 transgenesis in the analysis of the activity of a novel conserved enhancer from the developmentally regulated neural-specific esrrga gene. Reporter expression was highly variable among independent lines generated with Tol2, whereas all lines generated with PhiC31 into a single integration site displayed nearly identical, enhancer-specific reporter expression in brain nuclei. Moreover, we demonstrate that a modified integrase system can also be used for the detection of enhancer activity in transient transgenesis. These results demonstrate the power of the PhiC31-based transgene integration for the annotation and fine analysis of transcriptional regulatory elements and it promises to be a generally desirable tool for a range of applications, which rely on highly reproducible patterns of transgene activity in zebrafish.
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Affiliation(s)
- Jennifer Anne Roberts
- School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, B15 2TT, UK
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Rubinstein M, de Souza FSJ. Evolution of transcriptional enhancers and animal diversity. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130017. [PMID: 24218630 DOI: 10.1098/rstb.2013.0017] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Deciphering the genetic bases that drive animal diversity is one of the major challenges of modern biology. Although four decades ago it was proposed that animal evolution was mainly driven by changes in cis-regulatory DNA elements controlling gene expression rather than in protein-coding sequences, only now are powerful bioinformatics and experimental approaches available to accelerate studies into how the evolution of transcriptional enhancers contributes to novel forms and functions. In the introduction to this Theme Issue, we start by defining the general properties of transcriptional enhancers, such as modularity and the coexistence of tight sequence conservation with transcription factor-binding site shuffling as different mechanisms that maintain the enhancer grammar over evolutionary time. We discuss past and current methods used to identify cell-type-specific enhancers and provide examples of how enhancers originate de novo, change and are lost in particular lineages. We then focus in the central part of this Theme Issue on analysing examples of how the molecular evolution of enhancers may change form and function. Throughout this introduction, we present the main findings of the articles, reviews and perspectives contributed to this Theme Issue that together illustrate some of the great advances and current frontiers in the field.
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Affiliation(s)
- Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, , C1428ADN Buenos Aires, Argentina
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Pallavicini A, Canapa A, Barucca M, Alfőldi J, Biscotti MA, Buonocore F, De Moro G, Di Palma F, Fausto AM, Forconi M, Gerdol M, Makapedua DM, Turner-Meier J, Olmo E, Scapigliati G. Analysis of the transcriptome of the Indonesian coelacanth Latimeria menadoensis. BMC Genomics 2013; 14:538. [PMID: 23927401 PMCID: PMC3750513 DOI: 10.1186/1471-2164-14-538] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 06/26/2013] [Indexed: 02/01/2023] Open
Abstract
Background Latimeria menadoensis is a coelacanth species first identified in 1997 in Indonesia, at 10,000 Km of distance from its African congener. To date, only six specimens have been caught and just a very limited molecular data is available. In the present work we describe the de novo transcriptome assembly obtained from liver and testis samples collected from the fifth specimen ever caught of this species. Results The deep RNA sequencing performed with Illumina technologies generated 145,435,156 paired-end reads, accounting for ~14 GB of sequence data, which were de novo assembled using a Trinity/CLC combined strategy. The assembly output was processed and filtered producing a set of 66,308 contigs, whose quality was thoroughly assessed. The comparison with the recently sequenced genome of the African congener Latimeria chalumnae and with the available genomic resources of other vertebrates revealed a good reconstruction of full length transcripts and a high coverage of the predicted full coelacanth transcriptome. The RNA-seq analysis revealed remarkable differences in the expression profiles between the two tissues, allowing the identification of liver- and testis-specific transcripts which may play a fundamental role in important biological processes carried out by these two organs. Conclusion Given the high genomic affinity between the two coelacanth species, the here described de novo transcriptome assembly can be considered a valuable support tool for the improvement of gene prediction within the genome of L. chalumnae and a valuable resource for investigation of many aspects of tetrapod evolution.
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Barolo S. Shadow enhancers: frequently asked questions about distributed cis-regulatory information and enhancer redundancy. Bioessays 2012; 34:135-41. [PMID: 22083793 PMCID: PMC3517143 DOI: 10.1002/bies.201100121] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper, in the form of a frequently asked questions page (FAQ), addresses outstanding questions about "shadow enhancers", quasi-redundant cis-regulatory elements, and their proposed roles in transcriptional control. Questions include: What exactly are shadow enhancers? How many genes have shadow/redundant/distributed enhancers? How redundant are these elements? What is the function of distributed enhancers? How modular are enhancers? Is it useful to study a single enhancer in isolation? In addition, a revised definition of "shadow enhancers" is proposed, and possible mechanisms of shadow enhancer function and evolution are discussed.
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Affiliation(s)
- Scott Barolo
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA.
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Lang M, Hadzhiev Y, Siegel N, Amemiya CT, Parada C, Strähle U, Becker MB, Müller F, Meyer A. Conservation of shh cis-regulatory architecture of the coelacanth is consistent with its ancestral phylogenetic position. EvoDevo 2010; 1:11. [PMID: 21047394 PMCID: PMC2992049 DOI: 10.1186/2041-9139-1-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 11/03/2010] [Indexed: 12/17/2022] Open
Abstract
Background The modern coelacanth (Latimeria) is the extant taxon of a basal sarcopterygian lineage and sister group to tetrapods. Apart from certain apomorphic traits, its morphology is characterized by a high degree of retention of ancestral vertebrate structures and little morphological change. An insight into the molecular evolution that may explain the unchanged character of Latimeria morphology requires the analysis of the expression patterns of developmental regulator genes and their cis-regulatory modules (CRMs). Results We describe the comparative and functional analysis of the sonic hedgehog (shh) genomic region of Latimeria menadoensis. Several putative enhancers in the Latimeria shh locus have been identified by comparisons to sarcopterygian and actinopterygian extant species. Specific sequence conservation with all known actinopterygian enhancer elements has been detected. However, these elements are selectively missing in more recently diverged actinopterygian and sarcopterygian species. The functionality of the putative Latimeria enhancers was confirmed by reporter gene expression analysis in transient transgenic zebrafish and chick embryos. Conclusions Latimeria shh CRMs represent the ancestral set of enhancers that have emerged before the split of lobe-finned and ray-finned fishes. In contrast to lineage-specific losses and differentiations in more derived lineages, Latimeria shh enhancers reveal low levels of sequence diversification. High overall sequence conservation of shh conserved noncoding elements (CNE) is consistent with the general trend of high levels of conservation of noncoding DNA in the slowly evolving Latimeria genome.
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Affiliation(s)
- Michael Lang
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.,Development and Neurobiology Program, Jacques Monod Institute, 75013 Paris, France
| | - Yavor Hadzhiev
- Department of Medical and Molecular Genetics, University of Birmingham, Birmingham B15 2TT, UK
| | - Nicol Siegel
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.,Medical University of Vienna, Medical Genetics, 1090 Vienna, Austria
| | - Chris T Amemiya
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Carolina Parada
- Developmental Biology Group, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, 08003 Barcelona, Spain.,Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA 90030, USA
| | - Uwe Strähle
- Karlsruhe Institute of Technology, Institute for Toxicology and Genetics, 76021 Karlsruhe, Germany
| | - May-Britt Becker
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany.,Exzellenzcluster CellNetworks, INF 267, 69120 Heidelberg, Germany
| | - Ferenc Müller
- Department of Medical and Molecular Genetics, University of Birmingham, Birmingham B15 2TT, UK.,Karlsruhe Institute of Technology, Institute for Toxicology and Genetics, 76021 Karlsruhe, Germany
| | - Axel Meyer
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
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Kano S, Xiao JH, Osório J, Ekker M, Hadzhiev Y, Müller F, Casane D, Magdelenat G, Rétaux S. Two lamprey Hedgehog genes share non-coding regulatory sequences and expression patterns with gnathostome Hedgehogs. PLoS One 2010; 5:e13332. [PMID: 20967201 PMCID: PMC2954159 DOI: 10.1371/journal.pone.0013332] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 09/17/2010] [Indexed: 11/23/2022] Open
Abstract
Hedgehog (Hh) genes play major roles in animal development and studies of their evolution, expression and function point to major differences among chordates. Here we focused on Hh genes in lampreys in order to characterize the evolution of Hh signalling at the emergence of vertebrates. Screening of a cosmid library of the river lamprey Lampetra fluviatilis and searching the preliminary genome assembly of the sea lamprey Petromyzon marinus indicate that lampreys have two Hh genes, named Hha and Hhb. Phylogenetic analyses suggest that Hha and Hhb are lamprey-specific paralogs closely related to Sonic/Indian Hh genes. Expression analysis indicates that Hha and Hhb are expressed in a Sonic Hh-like pattern. The two transcripts are expressed in largely overlapping but not identical domains in the lamprey embryonic brain, including a newly-described expression domain in the nasohypophyseal placode. Global alignments of genomic sequences and local alignment with known gnathostome regulatory motifs show that lamprey Hhs share conserved non-coding elements (CNE) with gnathostome Hhs albeit with sequences that have significantly diverged and dispersed. Functional assays using zebrafish embryos demonstrate gnathostome-like midline enhancer activity for CNEs contained in intron2. We conclude that lamprey Hh genes are gnathostome Shh-like in terms of expression and regulation. In addition, they show some lamprey-specific features, including duplication and structural (but not functional) changes in the intronic/regulatory sequences.
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Affiliation(s)
- Shungo Kano
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
| | - Jin-Hua Xiao
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
| | - Joana Osório
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
| | - Marc Ekker
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
- Department of Biology, Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Canada
| | - Yavor Hadzhiev
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
- Department of Medical and Molecular Genetics, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Ferenc Müller
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
- Department of Medical and Molecular Genetics, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Didier Casane
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
- Laboratoire Evolution, Génomes et Spéciation UPR9034 Centre National de la Recherche Scientifique (CNRS), Gif-sur-Yvette, and Université Paris 7, Paris, France
| | - Ghislaine Magdelenat
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
- Génoscope, Institut de Génomique, Commissariat à l'Energie Atomique (CEA), Evry, France
| | - Sylvie Rétaux
- Laboratoire Neurobiologie et Développement UPR3294 Centre National de la Recherche Scientifique (CNRS), Institut Alfred Fessard, Gif-sur-Yvette, France
- * E-mail:
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10
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Yang L, Rastegar S, Strähle U. Regulatory interactions specifying Kolmer-Agduhr interneurons. Development 2010; 137:2713-22. [DOI: 10.1242/dev.048470] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the zebrafish spinal cord, two classes of neurons develop from the lateral floor plate: Kolmer-Agduhr′ (KA′) and V3 interneurons. We show here that the differentiation of the correct number of KA′ cells depends on the activity of the homeobox transcription factor Nkx2.9. This factor acts in concert with Nkx2.2a and Nkx2.2b. These factors are also required for the expression of the zinc-finger transcription factor Gata2 in the lateral floor plate. In turn, Gata2 is necessary for expression of the basic helix-loop-helix transcription factor Tal2 that acts upstream of the GABA-synthesizing enzyme glutamic acid decarboxylase 67 gene (gad67) in KA′ cells. Expression of the transcription factor Sim1, which marks the V3 interneurons in the lateral floor plate, depends also on the three Nkx2 factors. sim1 expression does not require, however, gata2 and tal2. KA′ cells of the lateral floor plate and the KA′ cells located more dorsally in the spinal cord share expression of transcription factors. The functional connections between the different regulatory genes, however, differ in the two GABAergic cell types: although gata2 and tal2 are expressed in KA′ cells, they are dispensable for gad67 expression in these cells. Instead, olig2 and gata3 are required for the differentiation of gad67-expressing KA′ cells. This suggests that the layout of regulatory networks is crucially dependent on the lineage that differs between KA′ and KA′ cells.
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Affiliation(s)
- Lixin Yang
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021 Karlsruhe, Germany
| | - Sepand Rastegar
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021 Karlsruhe, Germany
| | - Uwe Strähle
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021 Karlsruhe, Germany
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11
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12
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Rétaux S, Kano S. Midline signaling and evolution of the forebrain in chordates: a focus on the lamprey Hedgehog case. Integr Comp Biol 2010; 50:98-109. [PMID: 21558191 DOI: 10.1093/icb/icq032] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Lampreys are agnathans (vertebrates without jaws). They occupy a key phylogenetic position in the emergence of novelties and in the diversification of morphology at the dawn of vertebrates. We have used lampreys to investigate the possibility that embryonic midline signaling systems have been a driving force for the evolution of the forebrain in vertebrates. We have focused on Sonic Hedgehog/Hedgehog (Shh/Hh) signaling. In this article, we first review and summarize our recent work on the comparative analysis of embryonic expression patterns for Shh/Hh, together with Fgf8 (fibroblast growth factor 8) and Wnt (wingless-Int) pathway components, in the embryonic lamprey forebrain. Comparison with nonvertebrate chordates on one hand, and jawed vertebrates on the other hand, shows that these morphogens/growth factors acquired new expression domains in the most rostral part of the neural tube in lampreys compared to nonvertebrate chordates, and in jawed vertebrates compared to lampreys. These data are consistent with the idea that changes in Shh, Fgf8 or Wnt signaling in the course of evolution have been instrumental for the emergence and diversification of the telencephalon, a part of the forebrain that is unique to vertebrates. We have then used comparative genomics on Shh/Hh loci to identify commonalities and differences in noncoding regulatory sequences across species and phyla. Conserved noncoding elements (CNEs) can be detected in lamprey Hh introns, even though they display unique structural features and need adjustments of parameters used for in silico alignments to be detected, because of lamprey-specific properties of the genome. The data also show conservation of a ventral midline enhancer located in Shh/Hh intron 2 of all chordates, the very species which possess a notochord and a floor plate, but not in earlier emerged deuterostomes or protostomes. These findings exemplify how the Shh/Hh locus is one of the best loci to study genome evolution with regards to developmental events.
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Affiliation(s)
- Sylvie Rétaux
- NeD-UPR3294, CNRS, Institut Alfred Fessard, avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
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13
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Navratilova P, Fredman D, Lenhard B, Becker TS. Regulatory divergence of the duplicated chromosomal loci sox11a/b by subpartitioning and sequence evolution of enhancers in zebrafish. Mol Genet Genomics 2009; 283:171-84. [DOI: 10.1007/s00438-009-0503-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Accepted: 12/01/2009] [Indexed: 01/05/2023]
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Komisarczuk AZ, Kawakami K, Becker TS. Cis-regulation and chromosomal rearrangement of the fgf8 locus after the teleost/tetrapod split. Dev Biol 2009; 336:301-12. [PMID: 19782672 DOI: 10.1016/j.ydbio.2009.09.029] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Revised: 09/02/2009] [Accepted: 09/18/2009] [Indexed: 12/23/2022]
Abstract
The complex expression pattern of fibroblast growth factor 8 (Fgf8) and the cellular responses dependent on concentration of its mRNA in vertebrates suggest that Fgf8 should be tightly controlled at the transcriptional level. We found zebrafish conserved noncoding elements (CNEs) with pan-vertebrate as well as fish-specific orthologous sequences from across 200 kb of the zebrafish fgf8a genomic regulatory block to direct reporter expression in patterns consistent with the expression pattern of fgf8a. These included elements from inside the introns of the skin-specific slc2a15a and the ubiquitously expressed fbxw4 bystander genes. The fgf8a/fbxw4 gene pair, which has remained joined throughout three whole genome duplications in chordate evolution, is inverted in teleost genomes, but CNEs across both evolutionary breakpoints showed specific activity. While some CNEs directed highly reproducible expression patterns, others were subject to variation but showed, in a subset of transgenes, expression in the apical ectodermal ridge, the anterior boundaries of somites and the midbrain-hindbrain boundary, specific Fgf8 signaling domains, suggesting that their activity may be context specific. A human element with tetrapod-specific orthologous sequences directed reporter expression to the vasculature, possibly corresponding to a tetrapod innovation. We conclude that fgf8a transcriptional regulation employs pan-vertebrate and teleost-specific enhancers dispersed over three genes in the zebrafish genome.
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Affiliation(s)
- Anna Z Komisarczuk
- Sars Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgate 55, N-5008 Bergen, Norway
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The words of the regulatory code are arranged in a variable manner in highly conserved enhancers. Dev Biol 2008; 318:366-77. [PMID: 18455719 DOI: 10.1016/j.ydbio.2008.03.034] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 03/17/2008] [Accepted: 03/20/2008] [Indexed: 01/29/2023]
Abstract
The cis-regulatory regions of many developmental regulators and transcription factors are believed to be highly conserved in the genomes of vertebrate species, suggesting specific regulatory mechanisms for these gene classes. We functionally characterized five notochord enhancers, whose sequence is highly conserved, and systematically mutated two of them. Two subregions were identified to be essential for expression in the notochord of the zebrafish embryo. Synthetic enhancers containing the two essential regions in front of a TATA-box drive expression in the notochord while concatemerization of the subregions alone is not sufficient, indicating that the combination of the two sequence elements is required for notochord expression. Both regions are present in the five functionally characterized notochord enhancers. However, the position, the distance and relative orientation of the two sequence motifs can vary substantially within the enhancer sequences. This suggests that the regulatory grammar itself does not dictate the high evolutionary conservation between these orthologous cis-regulatory sequences. Rather, it represents a less well-conserved layer of sequence organization within these sequences.
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