1
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Hintermann A, Bolt CC, Hawkins MB, Valentin G, Lopez-Delisle L, Gitto S, Gómez PB, Mascrez B, Mansour TA, Nakamura T, Harris MP, Shubin NH, Duboule D. EVOLUTIONARY CO-OPTION OF AN ANCESTRAL CLOACAL REGULATORY LANDSCAPE DURING THE EMERGENCE OF DIGITS AND GENITALS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.24.586442. [PMID: 38585989 PMCID: PMC10996561 DOI: 10.1101/2024.03.24.586442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
The transition from fins to limbs has been a rich source of discussion for more than a century. One open and important issue is understanding how the mechanisms that pattern digits arose during vertebrate evolution. In this context, the analysis of Hox gene expression and functions to infer evolutionary scenarios has been a productive approach to explain the changes in organ formation, particularly in limbs. In tetrapods, the transcription of Hoxd genes in developing digits depends on a well-characterized set of enhancers forming a large regulatory landscape1,2. This control system has a syntenic counterpart in zebrafish, even though they lack bona fide digits, suggestive of deep homology3 between distal fin and limb developmental mechanisms. We tested the global function of this landscape to assess ancestry and source of limb and fin variation. In contrast to results in mice, we show here that the deletion of the homologous control region in zebrafish has a limited effect on the transcription of hoxd genes during fin development. However, it fully abrogates hoxd expression within the developing cloaca, an ancestral structure related to the mammalian urogenital sinus. We show that similar to the limb, Hoxd gene function in the urogenital sinus of the mouse also depends on enhancers located in this same genomic domain. Thus, we conclude that the current regulation underlying Hoxd gene expression in distal limbs was co-opted in tetrapods from a preexisting cloacal program. The orthologous chromatin domain in fishes may illustrate a rudimentary or partial step in this evolutionary co-option.
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Affiliation(s)
- Aurélie Hintermann
- Department of Genetics and Evolution, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva, Switzerland
| | - Christopher Chase Bolt
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
| | - M. Brent Hawkins
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA, Department of Orthopedic Research, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Guillaume Valentin
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
| | - Lucille Lopez-Delisle
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
| | - Sandra Gitto
- Department of Genetics and Evolution, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva, Switzerland
| | - Paula Barrera Gómez
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
| | - Bénédicte Mascrez
- Department of Genetics and Evolution, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva, Switzerland
| | | | - Tetsuya Nakamura
- Department of Genetics, Rutgers University, New Brunswick, NJ, USA
| | - Matthew P. Harris
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA, Department of Orthopedic Research, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Neil H. Shubin
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | - Denis Duboule
- Department of Genetics and Evolution, University of Geneva, 30 quai Ernest Ansermet, 1211, Geneva, Switzerland
- School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne EPFL, 1015 Lausanne, Switzerland
- Center for Interdisciplinary Research in Biology CIRB, Collège de France, CNRS, INSERM, Université PSL, Paris, France
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2
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Cumplido N, Arratia G, Desvignes T, Muñoz-Sánchez S, Postlethwait JH, Allende ML. Hox genes control homocercal caudal fin development and evolution. SCIENCE ADVANCES 2024; 10:eadj5991. [PMID: 38241378 PMCID: PMC10798566 DOI: 10.1126/sciadv.adj5991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 12/19/2023] [Indexed: 01/21/2024]
Abstract
Ancient bony fishes had heterocercal tails, like modern sharks and sturgeons, with asymmetric caudal fins and a vertebral column extending into an elongated upper lobe. Teleost fishes, in contrast, developed a homocercal tail characterized by two separate equal-sized fin lobes and the body axis not extending into the caudal fin. A similar heterocercal-to-homocercal transition occurs during teleost ontogeny, although the underlying genetic and developmental mechanisms for either transition remain unresolved. Here, we investigated the role of hox13 genes in caudal fin formation as these genes control posterior identity in animals. Analysis of expression profiles of zebrafish hox13 paralogs and phenotypes of CRISPR/Cas9-induced mutants showed that double hoxb13a and hoxc13a mutants fail to form a caudal fin. Furthermore, single mutants display heterocercal-like morphologies not seen since Mesozoic fossil teleosteomorphs. Relaxation of functional constraints after the teleost genome duplication may have allowed hox13 duplicates to neo- or subfunctionalize, ultimately contributing to the evolution of a homocercal tail in teleost fishes.
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Affiliation(s)
- Nicolás Cumplido
- Millennium Institute Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Gloria Arratia
- University of Kansas, Department of Ecology and Evolutionary Biology and Biodiversity Institute, Lawrence, KS, USA
| | - Thomas Desvignes
- Institute of Neuroscience, University of Oregon, Eugene, OR, USA
| | - Salomé Muñoz-Sánchez
- Millennium Institute Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | | - Miguel L. Allende
- Millennium Institute Center for Genome Regulation, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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3
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Crow KD, Sadakian A, Kaslly NA. The role of the 5' HoxA genes in the development of the hindgut, vent, and a novel sphincter in a derived teleost (bluebanded goby, Lythrypnus dalli). JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2023; 340:518-530. [PMID: 32779333 DOI: 10.1002/jez.b.22982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 05/05/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Unique expression patterns of the 5' HoxA genes are associated with the evolution and development of novel features including claspers in cartilaginous fishes, modified pectoral fins in batoids, and the yolk sac extension in Cypriniformes. Here, we demonstrate a role for HoxA11a and HoxA13a in demarcating the hindgut in fishes of the family Gobiidae, including a novel sphincter called the intestinal rectal sphincter (IRS). Disruption of 5' HoxA expression, via manipulation of retinoic acid signaling, results in failure of the IRS and/or vent to develop. Furthermore, exposure to HoxA disruptors alters 5' HoxA expression, in association with developmental phenotypes, demonstrating a functional link between 5' HoxA expression and development of a novel feature in the bluebanded goby, Lythrypnus dalli.
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Affiliation(s)
- Karen D Crow
- Department of Biology, San Francisco State University, San Francisco, California
| | - Ara Sadakian
- Department of Biology, San Francisco State University, San Francisco, California
| | - Noelle A Kaslly
- Department of Biology, San Francisco State University, San Francisco, California
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4
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England SJ, Rusnock AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular analyses of zebrafish V0v spinal interneurons and identification of transcriptional regulators downstream of Evx1 and Evx2 in these cells. Neural Dev 2023; 18:8. [PMID: 38017520 PMCID: PMC10683209 DOI: 10.1186/s13064-023-00176-w] [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: 08/23/2023] [Accepted: 10/12/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. METHODS To identify candidate members of V0v gene regulatory networks, we FAC-sorted wild-type and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. RESULTS Our data reveal two molecularly distinct subtypes of zebrafish V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuron expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. CONCLUSIONS This study identifies two molecularly distinct subsets of zebrafish V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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Affiliation(s)
| | | | - Amra Mujcic
- Biology Department, Syracuse University, Syracuse, NY, USA
| | | | - Sarah de Jager
- Physiology, Development and Neuroscience Department, Cambridge University, Cambridge, UK
| | | | - José L Juárez-Morales
- Biology Department, Syracuse University, Syracuse, NY, USA
- Programa de IxM-CONAHCYT, Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), La Paz, Baja California Sur, México
| | | | - Ginny Grieb
- Biology Department, Syracuse University, Syracuse, NY, USA
| | - Santanu Banerjee
- Biological Sciences Department, SUNY-Cortland, Cortland, NY, USA
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Marlétaz F, Timoshevskaya N, Timoshevskiy V, Simakov O, Parey E, Gavriouchkina D, Suzuki M, Kubokawa K, Brenner S, Smith J, Rokhsar DS. The hagfish genome and the evolution of vertebrates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537254. [PMID: 37131617 PMCID: PMC10153176 DOI: 10.1101/2023.04.17.537254] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
As the only surviving lineages of jawless fishes, hagfishes and lampreys provide a critical window into early vertebrate evolution. Here, we investigate the complex history, timing, and functional role of genome-wide duplications in vertebrates in the light of a chromosome-scale genome of the brown hagfish Eptatretus atami. Using robust chromosome-scale (paralogon-based) phylogenetic methods, we confirm the monophyly of cyclostomes, document an auto-tetraploidization (1RV) that predated the origin of crown group vertebrates ~517 Mya, and establish the timing of subsequent independent duplications in the gnathostome and cyclostome lineages. Some 1RV gene duplications can be linked to key vertebrate innovations, suggesting that this early genomewide event contributed to the emergence of pan-vertebrate features such as neural crest. The hagfish karyotype is derived by numerous fusions relative to the ancestral cyclostome arrangement preserved by lampreys. These genomic changes were accompanied by the loss of genes essential for organ systems (eyes, osteoclast) that are absent in hagfish, accounting in part for the simplification of the hagfish body plan; other gene family expansions account for hagfishes' capacity to produce slime. Finally, we characterise programmed DNA elimination in somatic cells of hagfish, identifying protein-coding and repetitive elements that are deleted during development. As in lampreys, the elimination of these genes provides a mechanism for resolving genetic conflict between soma and germline by repressing germline/pluripotency functions. Reconstruction of the early genomic history of vertebrates provides a framework for further exploration of vertebrate novelties.
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Affiliation(s)
- Ferdinand Marlétaz
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, UK
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | | | | | - Oleg Simakov
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Department of Molecular Evolution and Development, University of Vienna, Vienna, Austria
| | - Elise Parey
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Daria Gavriouchkina
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Present address: UK Dementia Research Institute, University College London, London, UK
| | - Masakazu Suzuki
- Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, Japan
| | - Kaoru Kubokawa
- Ocean Research Institute, The University of Tokyo, Tokyo, Japan
| | - Sydney Brenner
- Comparative and Medical Genomics Laboratory, Institute of Molecular and Cell Biology, A*STAR, Biopolis, Singapore 138673, Singapore
- Deceased
| | - Jeramiah Smith
- Department of Biology, University of Kentucky, Lexington, KY, USA
| | - Daniel S Rokhsar
- Molecular Genetics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
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6
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Truong BT, Shull LC, Lencer E, Bend EG, Field M, Blue EE, Bamshad MJ, Skinner C, Everman D, Schwartz CE, Flanagan-Steet H, Artinger KB. PRDM1 DNA-binding zinc finger domain is required for normal limb development and is disrupted in split hand/foot malformation. Dis Model Mech 2023; 16:dmm049977. [PMID: 37083955 PMCID: PMC10151829 DOI: 10.1242/dmm.049977] [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: 11/10/2022] [Accepted: 03/09/2023] [Indexed: 04/22/2023] Open
Abstract
Split hand/foot malformation (SHFM) is a rare limb abnormality with clefting of the fingers and/or toes. For many individuals, the genetic etiology is unknown. Through whole-exome and targeted sequencing, we detected three novel variants in a gene encoding a transcription factor, PRDM1, that arose de novo in families with SHFM or segregated with the phenotype. PRDM1 is required for limb development; however, its role is not well understood and it is unclear how the PRDM1 variants affect protein function. Using transient and stable overexpression rescue experiments in zebrafish, we show that the variants disrupt the proline/serine-rich and DNA-binding zinc finger domains, resulting in a dominant-negative effect. Through gene expression assays, RNA sequencing, and CUT&RUN in isolated pectoral fin cells, we demonstrate that Prdm1a directly binds to and regulates genes required for fin induction, outgrowth and anterior/posterior patterning, such as fgfr1a, dlx5a, dlx6a and smo. Taken together, these results improve our understanding of the role of PRDM1 in the limb gene regulatory network and identified novel PRDM1 variants that link to SHFM in humans.
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Affiliation(s)
- Brittany T. Truong
- Human Medical Genetics & Genomics Graduate Program, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
- Department of Craniofacial Biology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Lomeli C. Shull
- Department of Craniofacial Biology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ezra Lencer
- Biology Department, Lafayette College, Easton, PA 18042, USA
| | - Eric G. Bend
- Greenwood Genetics Center, Greenwood, SC 29646, USA
| | - Michael Field
- Genetics of Learning Disability Service, Hunter Genetics, Waratah, NSW 2298, AUS
| | - Elizabeth E. Blue
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195, USA
- Brotman-Baty Institute for Precision Medicine, Seattle, WA 98195, USA
| | - Michael J. Bamshad
- Brotman-Baty Institute for Precision Medicine, Seattle, WA 98195, USA
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | | | | | | | | | - Kristin B. Artinger
- Department of Craniofacial Biology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA
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7
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Schulreich SM, Salamanca-Díaz DA, Zieger E, Calcino AD, Wanninger A. A mosaic of conserved and novel modes of gene expression and morphogenesis in mesoderm and muscle formation of a larval bivalve. ORG DIVERS EVOL 2022; 22:893-913. [PMID: 36398106 PMCID: PMC9649484 DOI: 10.1007/s13127-022-00569-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/26/2022] [Indexed: 10/17/2022]
Abstract
The mesoderm gives rise to several key morphological features of bilaterian animals including endoskeletal elements and the musculature. A number of regulatory genes involved in mesoderm and/or muscle formation (e.g., Brachyury (Bra), even-skipped (eve), Mox, myosin II heavy chain (mhc)) have been identified chiefly from chordates and the ecdysozoans Drosophila and Caenorhabditis elegans, but data for non-model protostomes, especially those belonging to the ecdysozoan sister clade, Lophotrochozoa (e.g., flatworms, annelids, mollusks), are only beginning to emerge. Within the lophotrochozoans, Mollusca constitutes the most speciose and diverse phylum. Interestingly, however, information on the morphological and molecular underpinnings of key ontogenetic processes such as mesoderm formation and myogenesis remains scarce even for prominent molluscan sublineages such as the bivalves. Here, we investigated myogenesis and developmental expression of Bra, eve, Mox, and mhc in the quagga mussel Dreissena rostriformis, an invasive freshwater bivalve and an emerging model in invertebrate evodevo. We found that all four genes are expressed during mesoderm formation, but some show additional, individual sites of expression during ontogeny. While Mox and mhc are involved in early myogenesis, eve is also expressed in the embryonic shell field and Bra is additionally present in the foregut. Comparative analysis suggests that Mox has an ancestral role in mesoderm and possibly muscle formation in bilaterians, while Bra and eve are conserved regulators of mesoderm development of nephrozoans (protostomes and deuterostomes). The fully developed Dreissena veliger larva shows a highly complex muscular architecture, supporting a muscular ground pattern of autobranch bivalve larvae that includes at least a velum muscle ring, three or four pairs of velum retractors, one or two pairs of larval retractors, two pairs of foot retractors, a pedal plexus, possibly two pairs of mantle retractors, and the muscles of the pallial line, as well as an anterior and a posterior adductor. As is typical for their molluscan kin, remodelling and loss of prominent larval features such as the velum musculature and various retractor systems appear to be also common in bivalves. Supplementary information The online version contains supplementary material available at 10.1007/s13127-022-00569-5.
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Affiliation(s)
- Stephan M. Schulreich
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - David A. Salamanca-Díaz
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Elisabeth Zieger
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andrew D. Calcino
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
| | - Andreas Wanninger
- Unit for Integrative Zoology, Department of Evolutionary Biology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
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8
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McGarvey AC, Kopp W, Vučićević D, Mattonet K, Kempfer R, Hirsekorn A, Bilić I, Gil M, Trinks A, Merks AM, Panáková D, Pombo A, Akalin A, Junker JP, Stainier DY, Garfield D, Ohler U, Lacadie SA. Single-cell-resolved dynamics of chromatin architecture delineate cell and regulatory states in zebrafish embryos. CELL GENOMICS 2022; 2:100083. [PMID: 36777038 PMCID: PMC9903790 DOI: 10.1016/j.xgen.2021.100083] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/24/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022]
Abstract
DNA accessibility of cis-regulatory elements (CREs) dictates transcriptional activity and drives cell differentiation during development. While many genes regulating embryonic development have been identified, the underlying CRE dynamics controlling their expression remain largely uncharacterized. To address this, we produced a multimodal resource and genomic regulatory map for the zebrafish community, which integrates single-cell combinatorial indexing assay for transposase-accessible chromatin with high-throughput sequencing (sci-ATAC-seq) with bulk histone PTMs and Hi-C data to achieve a genome-wide classification of the regulatory architecture determining transcriptional activity in the 24-h post-fertilization (hpf) embryo. We characterized the genome-wide chromatin architecture at bulk and single-cell resolution, applying sci-ATAC-seq on whole 24-hpf stage zebrafish embryos, generating accessibility profiles for ∼23,000 single nuclei. We developed a genome segmentation method, ScregSeg (single-cell regulatory landscape segmentation), for defining regulatory programs, and candidate CREs, specific to one or more cell types. We integrated the ScregSeg output with bulk measurements for histone post-translational modifications and 3D genome organization and identified new regulatory principles between chromatin modalities prevalent during zebrafish development. Sci-ATAC-seq profiling of npas4l/cloche mutant embryos identified novel cellular roles for this hematovascular transcriptional master regulator and suggests an intricate mechanism regulating its expression. Our work defines regulatory architecture and principles in the zebrafish embryo and establishes a resource of cell-type-specific genome-wide regulatory annotations and candidate CREs, providing a valuable open resource for genomics, developmental, molecular, and computational biology.
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Affiliation(s)
- Alison C. McGarvey
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany,Quantitative Developmental Biology, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany
| | - Wolfgang Kopp
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany,Bioinformatics and Omics Data Science Platform, Berlin Institute for Medical Systems Biology, Max Delbrück Centre for Molecular Medicine, Berlin 10115, Germany
| | - Dubravka Vučićević
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany
| | - Kenny Mattonet
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim 61231, Germany
| | - Rieke Kempfer
- Epigenetic Regulation and Chromatin Architecture, Berlin Institute for Medical Systems Biology, Max Delbrück Centre for Molecular Medicine, Berlin, Germany,Institute for Biology, Humboldt Universität Berlin, Berlin 10115, Germany
| | - Antje Hirsekorn
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany
| | - Ilija Bilić
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany
| | - Marine Gil
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany
| | - Alexandra Trinks
- IRI Life Sciences, Humboldt Universität Berlin, Berlin 10115, Germany
| | - Anne Margarete Merks
- Electrochemical Signaling in Development and Disease, Max Delbrück Centre for Molecular Medicine, Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin 13125, Germany
| | - Daniela Panáková
- Electrochemical Signaling in Development and Disease, Max Delbrück Centre for Molecular Medicine, Berlin, Germany,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin 13125, Germany
| | - Ana Pombo
- Epigenetic Regulation and Chromatin Architecture, Berlin Institute for Medical Systems Biology, Max Delbrück Centre for Molecular Medicine, Berlin, Germany,Institute for Biology, Humboldt Universität Berlin, Berlin 10115, Germany
| | - Altuna Akalin
- Bioinformatics and Omics Data Science Platform, Berlin Institute for Medical Systems Biology, Max Delbrück Centre for Molecular Medicine, Berlin 10115, Germany
| | - Jan Philipp Junker
- Quantitative Developmental Biology, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany
| | - Didier Y.R. Stainier
- Department of Developmental Genetics, Max Planck Institute for Heart and Lung Research, Bad Nauheim 61231, Germany
| | - David Garfield
- IRI Life Sciences, Humboldt Universität Berlin, Berlin 10115, Germany
| | - Uwe Ohler
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany,Institute for Biology, Humboldt Universität Berlin, Berlin 10115, Germany,Corresponding author
| | - Scott Allen Lacadie
- Computational Regulatory Genomics, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin 10115, Germany,Berlin Institute of Health, Berlin 10178, Germany,Corresponding author
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9
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hox gene expression predicts tetrapod-like axial regionalization in the skate, Leucoraja erinacea. Proc Natl Acad Sci U S A 2021; 118:2114563118. [PMID: 34903669 PMCID: PMC8713815 DOI: 10.1073/pnas.2114563118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2021] [Indexed: 01/11/2023] Open
Abstract
The axial skeleton of tetrapods is organized into distinct anteroposterior regions of the vertebral column (cervical, trunk, sacral, and caudal), and transitions between these regions are determined by colinear anterior expression boundaries of Hox5/6, -9, -10, and -11 paralogy group genes within embryonic paraxial mesoderm. Fishes, conversely, exhibit little in the way of discrete axial regionalization, and this has led to scenarios of an origin of Hox-mediated axial skeletal complexity with the evolutionary transition to land in tetrapods. Here, combining geometric morphometric analysis of vertebral column morphology with cell lineage tracing of hox gene expression boundaries in developing embryos, we recover evidence of at least five distinct regions in the vertebral skeleton of a cartilaginous fish, the little skate (Leucoraja erinacea). We find that skate embryos exhibit tetrapod-like anteroposterior nesting of hox gene expression in their paraxial mesoderm, and we show that anterior expression boundaries of hox5/6, hox9, hox10, and hox11 paralogy group genes predict regional transitions in the differentiated skate axial skeleton. Our findings suggest that hox-based axial skeletal regionalization did not originate with tetrapods but rather has a much deeper evolutionary history than was previously appreciated.
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10
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Hawkins MB, Henke K, Harris MP. Latent developmental potential to form limb-like skeletal structures in zebrafish. Cell 2021; 184:899-911.e13. [PMID: 33545089 DOI: 10.1016/j.cell.2021.01.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/28/2020] [Accepted: 01/04/2021] [Indexed: 12/13/2022]
Abstract
Changes in appendage structure underlie key transitions in vertebrate evolution. Addition of skeletal elements along the proximal-distal axis facilitated critical transformations, including the fin-to-limb transition that permitted generation of diverse modes of locomotion. Here, we identify zebrafish mutants that form supernumerary long bones in their pectoral fins. These new bones integrate into musculature, form joints, and articulate with neighboring elements. This phenotype is caused by activating mutations in previously unrecognized regulators of appendage patterning, vav2 and waslb, that function in a common pathway. This pathway is required for appendage development across vertebrates, and loss of Wasl in mice causes defects similar to those seen in murine Hox mutants. Concordantly, formation of supernumerary bones requires Hox11 function, and mutations in the vav2/wasl pathway drive enhanced expression of hoxa11b, indicating developmental homology with the forearm. Our findings reveal a latent, limb-like pattern ability in fins that is activated by simple genetic perturbation.
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Affiliation(s)
- M Brent Hawkins
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Orthopedic Research, Boston Children's Hospital, Boston, MA 02115, USA; Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Katrin Henke
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Orthopedic Research, Boston Children's Hospital, Boston, MA 02115, USA
| | - Matthew P Harris
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Orthopedic Research, Boston Children's Hospital, Boston, MA 02115, USA.
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11
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Reassessing the Role of Hox Genes during Vertebrate Development and Evolution. Trends Genet 2018; 34:209-217. [PMID: 29269261 DOI: 10.1016/j.tig.2017.11.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/21/2017] [Accepted: 11/29/2017] [Indexed: 12/13/2022]
Abstract
Since their discovery Hox genes have been at the core of the established models explaining the development and evolution of the vertebrate body plan as well as its paired appendages. Recent work brought new light to their role in the patterning processes along the main body axis. These studies show that Hox genes do not control the basic layout of the vertebrate body plan but carry out region-specific patterning instructions loaded on the derivatives of axial progenitors by Hox-independent processes. Furthermore, the finding that Hox clusters are embedded in functional chromatin domains, which critically impacts their expression, has significantly altered our understanding of the mechanisms of Hox gene regulation. This new conceptual framework has broadened our understanding of both limb development and the evolution of vertebrate paired appendages.
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You X, Sun M, Li J, Bian C, Chen J, Yi Y, Yu H, Shi Q. Mudskippers and Their Genetic Adaptations to an Amphibious Lifestyle. Animals (Basel) 2018; 8:E24. [PMID: 29414871 PMCID: PMC5836032 DOI: 10.3390/ani8020024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/25/2018] [Accepted: 02/03/2018] [Indexed: 02/07/2023] Open
Abstract
Mudskippers are the largest group of amphibious teleost fish that are uniquely adapted to live on mudflats. During their successful transition from aqueous life to terrestrial living, these fish have evolved morphological and physiological modifications of aerial vision and olfaction, higher ammonia tolerance, aerial respiration, improved immunological defense against terrestrial pathogens, and terrestrial locomotion using protruded pectoral fins. Comparative genomic and transcriptomic data have been accumulated and analyzed for understanding molecular mechanisms of the terrestrial adaptations. Our current review provides a general introduction to mudskippers and recent research advances of their genetic adaptations to the amphibious lifestyle, which will be helpful for understanding the evolutionary transition of vertebrates from water to land. Our insights into the genomes and transcriptomes will also support molecular breeding, functional identification, and natural compound screening.
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Affiliation(s)
- Xinxin You
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518063, China.
| | - Min Sun
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
| | - Jia Li
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
| | - Chao Bian
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518063, China.
| | - Jieming Chen
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI-Zhenjiang Institute of Hydrobiology, BGI Marine, BGI, Zhenjiang 212000, China.
| | - Yunhai Yi
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518063, China.
| | - Hui Yu
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
| | - Qiong Shi
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518063, China.
- Laboratory of Aquatic Genomics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
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13
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Kherdjemil Y, Kmita M. Insights on the role of hox genes in the emergence of the pentadactyl ground state. Genesis 2017; 56. [DOI: 10.1002/dvg.23046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 06/19/2017] [Accepted: 06/22/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Yacine Kherdjemil
- Laboratory of Genetics and Development; Institut de Recherches Cliniques de Montréal (IRCM); 110 avenue des Pins Ouest, Montréal, QC H2W1R7 Canada
- Département de Médecine (Programme de Biologie Moléculaire); Université de Montréal; Montréal QC H3T 1J4 Canada
| | - Marie Kmita
- Laboratory of Genetics and Development; Institut de Recherches Cliniques de Montréal (IRCM); 110 avenue des Pins Ouest, Montréal, QC H2W1R7 Canada
- Département de Médecine (Programme de Biologie Moléculaire); Université de Montréal; Montréal QC H3T 1J4 Canada
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14
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Kherdjemil Y, Lalonde RL, Sheth R, Dumouchel A, de Martino G, Pineault KM, Wellik DM, Stadler HS, Akimenko MA, Kmita M. Evolution of Hoxa11 regulation in vertebrates is linked to the pentadactyl state. Nature 2016; 539:89-92. [PMID: 27706137 PMCID: PMC5558051 DOI: 10.1038/nature19813] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 08/26/2016] [Indexed: 11/08/2022]
Abstract
The fin-to-limb transition represents one of the major vertebrate morphological innovations associated with the transition from aquatic to terrestrial life and is an attractive model for gaining insights into the mechanisms of morphological diversity between species. One of the characteristic features of limbs is the presence of digits at their extremities. Although most tetrapods have limbs with five digits (pentadactyl limbs), palaeontological data indicate that digits emerged in lobed fins of early tetrapods, which were polydactylous. How the transition to pentadactyl limbs occurred remains unclear. Here we show that the mutually exclusive expression of the mouse genes Hoxa11 and Hoxa13, which were previously proposed to be involved in the origin of the tetrapod limb, is required for the pentadactyl state. We further demonstrate that the exclusion of Hoxa11 from the Hoxa13 domain relies on an enhancer that drives antisense transcription at the Hoxa11 locus after activation by HOXA13 and HOXD13. Finally, we show that the enhancer that drives antisense transcription of the mouse Hoxa11 gene is absent in zebrafish, which, together with the largely overlapping expression of hoxa11 and hoxa13 genes reported in fish, suggests that this enhancer emerged in the course of the fin-to-limb transition. On the basis of the polydactyly that we observed after expression of Hoxa11 in distal limbs, we propose that the evolution of Hoxa11 regulation contributed to the transition from polydactyl limbs in stem-group tetrapods to pentadactyl limbs in extant tetrapods.
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Affiliation(s)
- Yacine Kherdjemil
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada
- Département de Médecine (Programme de Biologie Moléculaire), Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Robert L Lalonde
- Department of Biology and CAREG, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Rushikesh Sheth
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada
| | - Annie Dumouchel
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada
| | - Gemma de Martino
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada
| | - Kyriel M Pineault
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, Michigan 48109-2200, USA
| | - Deneen M Wellik
- Department of Internal Medicine, Division of Molecular Medicine and Genetics, University of Michigan, Ann Arbor, Michigan 48109-2200, USA
| | | | - Marie-Andrée Akimenko
- Department of Biology and CAREG, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - Marie Kmita
- Genetics and Development Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, Québec H2W 1R7, Canada
- Département de Médecine (Programme de Biologie Moléculaire), Université de Montréal, Montréal, Québec H3T 1J4, Canada
- Department of Experimental Medicine, McGill University, Montreal, Quebec H3A 1A3, Canada
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15
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Hilinski WC, Bostrom JR, England SJ, Juárez-Morales JL, de Jager S, Armant O, Legradi J, Strähle U, Link BA, Lewis KE. Lmx1b is required for the glutamatergic fates of a subset of spinal cord neurons. Neural Dev 2016; 11:16. [PMID: 27553035 PMCID: PMC4995821 DOI: 10.1186/s13064-016-0070-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/08/2016] [Indexed: 01/27/2023] Open
Abstract
Background Alterations in neurotransmitter phenotypes of specific neurons can cause imbalances in excitation and inhibition in the central nervous system (CNS), leading to diseases. Therefore, the correct specification and maintenance of neurotransmitter phenotypes is vital. As with other neuronal properties, neurotransmitter phenotypes are often specified and maintained by particular transcription factors. However, the specific molecular mechanisms and transcription factors that regulate neurotransmitter phenotypes remain largely unknown. Methods In this paper we use single mutant, double mutant and transgenic zebrafish embryos to elucidate the functions of Lmx1ba and Lmx1bb in the regulation of spinal cord interneuron neurotransmitter phenotypes. Results We demonstrate that lmx1ba and lmx1bb are both expressed in zebrafish spinal cord and that lmx1bb is expressed by both V0v cells and dI5 cells. Our functional analyses demonstrate that these transcription factors are not required for neurotransmitter fate specification at early stages of development, but that in embryos with at least two lmx1ba and/or lmx1bb mutant alleles there is a reduced number of excitatory (glutamatergic) spinal interneurons at later stages of development. In contrast, there is no change in the numbers of V0v or dI5 cells. These data suggest that lmx1b-expressing spinal neurons still form normally, but at least a subset of them lose, or do not form, their normal excitatory fates. As the reduction in glutamatergic cells is only seen at later stages of development, Lmx1b is probably required either for the maintenance of glutamatergic fates or to specify glutamatergic phenotypes of a subset of later forming neurons. Using double labeling experiments, we also show that at least some of the cells that lose their normal glutamatergic phenotype are V0v cells. Finally, we also establish that Evx1 and Evx2, two transcription factors that are required for V0v cells to acquire their excitatory neurotransmitter phenotype, are also required for lmx1ba and lmx1bb expression in these cells, suggesting that Lmx1ba and Lmx1bb act downstream of Evx1 and Evx2 in V0v cells. Conclusions Lmx1ba and Lmx1bb function at least partially redundantly in the spinal cord and three functional lmx1b alleles are required in zebrafish for correct numbers of excitatory spinal interneurons at later developmental stages. Taken together, our data significantly enhance our understanding of how spinal cord neurotransmitter fates are regulated.
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Affiliation(s)
- William C Hilinski
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.,Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Avenue, Syracuse, NY, 13210, USA
| | - Jonathan R Bostrom
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Samantha J England
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Sarah de Jager
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Olivier Armant
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Postfach 3640, 76021, Karlsruhe, Germany
| | - Jessica Legradi
- 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
| | - Brian A Link
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI, 53226, USA
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
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16
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Juárez-Morales JL, Schulte CJ, Pezoa SA, Vallejo GK, Hilinski WC, England SJ, de Jager S, Lewis KE. Evx1 and Evx2 specify excitatory neurotransmitter fates and suppress inhibitory fates through a Pax2-independent mechanism. Neural Dev 2016; 11:5. [PMID: 26896392 PMCID: PMC4759709 DOI: 10.1186/s13064-016-0059-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/04/2016] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND For neurons to function correctly in neuronal circuitry they must utilize appropriate neurotransmitters. However, even though neurotransmitter specificity is one of the most important and defining properties of a neuron we still do not fully understand how neurotransmitter fates are specified during development. Most neuronal properties are determined by the transcription factors that neurons express as they start to differentiate. While we know a few transcription factors that specify the neurotransmitter fates of particular neurons, there are still many spinal neurons for which the transcription factors specifying this critical phenotype are unknown. Strikingly, all of the transcription factors that have been identified so far as specifying inhibitory fates in the spinal cord act through Pax2. Even Tlx1 and Tlx3, which specify the excitatory fates of dI3 and dI5 spinal neurons work at least in part by down-regulating Pax2. METHODS In this paper we use single and double mutant zebrafish embryos to identify the spinal cord functions of Evx1 and Evx2. RESULTS We demonstrate that Evx1 and Evx2 are expressed by spinal cord V0v cells and we show that these cells develop into excitatory (glutamatergic) Commissural Ascending (CoSA) interneurons. In the absence of both Evx1 and Evx2, V0v cells still form and develop a CoSA morphology. However, they lose their excitatory fate and instead express markers of a glycinergic fate. Interestingly, they do not express Pax2, suggesting that they are acquiring their inhibitory fate through a novel Pax2-independent mechanism. CONCLUSIONS Evx1 and Evx2 are required, partially redundantly, for spinal cord V0v cells to become excitatory (glutamatergic) interneurons. These results significantly increase our understanding of the mechanisms of neuronal specification and the genetic networks involved in these processes.
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Affiliation(s)
- José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Claus J Schulte
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Sofia A Pezoa
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Grace K Vallejo
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - William C Hilinski
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, 505 Irving Avenue, Syracuse, NY, 13210, USA
| | - Samantha J England
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA
| | - Sarah de Jager
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, NY, 13244, USA.
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17
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Heckscher ES, Zarin AA, Faumont S, Clark MQ, Manning L, Fushiki A, Schneider-Mizell CM, Fetter RD, Truman JW, Zwart MF, Landgraf M, Cardona A, Lockery SR, Doe CQ. Even-Skipped(+) Interneurons Are Core Components of a Sensorimotor Circuit that Maintains Left-Right Symmetric Muscle Contraction Amplitude. Neuron 2015; 88:314-29. [PMID: 26439528 PMCID: PMC4619170 DOI: 10.1016/j.neuron.2015.09.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 07/30/2015] [Accepted: 09/02/2015] [Indexed: 11/16/2022]
Abstract
Bilaterally symmetric motor patterns--those in which left-right pairs of muscles contract synchronously and with equal amplitude (such as breathing, smiling, whisking, and locomotion)--are widespread throughout the animal kingdom. Yet, surprisingly little is known about the underlying neural circuits. We performed a thermogenetic screen to identify neurons required for bilaterally symmetric locomotion in Drosophila larvae and identified the evolutionarily conserved Even-skipped(+) interneurons (Eve/Evx). Activation or ablation of Eve(+) interneurons disrupted bilaterally symmetric muscle contraction amplitude, without affecting the timing of motor output. Eve(+) interneurons are not rhythmically active and thus function independently of the locomotor CPG. GCaMP6 calcium imaging of Eve(+) interneurons in freely moving larvae showed left-right asymmetric activation that correlated with larval behavior. TEM reconstruction of Eve(+) interneuron inputs and outputs showed that the Eve(+) interneurons are at the core of a sensorimotor circuit capable of detecting and modifying body wall muscle contraction.
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Affiliation(s)
- Ellie S Heckscher
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA.
| | - Aref Arzan Zarin
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA
| | - Serge Faumont
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Matthew Q Clark
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA
| | - Laurina Manning
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA
| | - Akira Fushiki
- Janelia Research Campus, HHMI, Ashburn, VA 20147, USA
| | | | | | | | - Maarten F Zwart
- Janelia Research Campus, HHMI, Ashburn, VA 20147, USA; Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | - Matthias Landgraf
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK
| | | | - Shawn R Lockery
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA
| | - Chris Q Doe
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA; Howard Hughes Medical Institute, University of Oregon, Eugene, OR 97403, USA.
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18
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Gredler ML, Seifert AW, Cohn MJ. Morphogenesis and Patterning of the Phallus and Cloaca in the American Alligator, Alligator mississippiensis. Sex Dev 2014; 9:53-67. [DOI: 10.1159/000364817] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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19
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Lara-Ramírez R, Zieger E, Schubert M. Retinoic acid signaling in spinal cord development. Int J Biochem Cell Biol 2013; 45:1302-13. [PMID: 23579094 DOI: 10.1016/j.biocel.2013.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Revised: 03/25/2013] [Accepted: 04/02/2013] [Indexed: 12/13/2022]
Abstract
Retinoic acid (RA) is an important signaling molecule mediating intercellular communication through vertebrate development. Here, we present and discuss recent information on the roles of the RA signaling pathway in spinal cord development. RA is an important player in the patterning and definition of the spinal cord territory from very early stages of development, even before the appearance of the neural plate and further serves a role in the patterning of the spinal cord both along the dorsoventral and anteroposterior axes, particularly in the promotion of neuronal differentiation. It is thus required to establish a variety of neuronal cell types at specific positions of the spinal cord. The main goal of this review is to gather information from vertebrate models, including fish, frogs, chicken and mice, and to put this information in a comparative context in an effort to visualize how the RA pathway was incorporated into the evolving vertebrate spinal cord and to identify mechanisms that are both common and different in the various vertebrate models. In doing so, we try to reconstruct how spinal cord development has been regulated by the RA signaling cascade through vertebrate diversification, highlighting areas which require further studies to obtain a better understanding of the evolutionary events that shaped this structure in the vertebrate lineage.
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Affiliation(s)
- Ricardo Lara-Ramírez
- Laboratoire de Biologie du Développement de Villefranche-sur-Mer, UMR 7009 - CNRS/UPMC, EvoInSiDe Team, Observatoire Océanologique, 181 Chemin du Lazaret, BP 28, 06230 Villefranche-sur-Mer, France
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20
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Seaver EC, Yamaguchi E, Richards GS, Meyer NP. Expression of the pair-rule gene homologs runt, Pax3/7, even-skipped-1 and even-skipped-2 during larval and juvenile development of the polychaete annelid Capitella teleta does not support a role in segmentation. EvoDevo 2012; 3:8. [PMID: 22510249 PMCID: PMC3359188 DOI: 10.1186/2041-9139-3-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 04/18/2012] [Indexed: 02/07/2023] Open
Abstract
Background Annelids and arthropods each possess a segmented body. Whether this similarity represents an evolutionary convergence or inheritance from a common segmented ancestor is the subject of ongoing investigation. Methods To investigate whether annelids and arthropods share molecular components that control segmentation, we isolated orthologs of the Drosophila melanogaster pair-rule genes, runt, paired (Pax3/7) and eve, from the polychaete annelid Capitella teleta and used whole mount in situ hybridization to characterize their expression patterns. Results When segments first appear, expression of the single C. teleta runt ortholog is only detected in the brain. Later, Ct-runt is expressed in the ventral nerve cord, foregut and hindgut. Analysis of Pax genes in the C. teleta genome reveals the presence of a single Pax3/7 ortholog. Ct-Pax3/7 is initially detected in the mid-body prior to segmentation, but is restricted to two longitudinal bands in the ventral ectoderm. Each of the two C. teleta eve orthologs has a unique and complex expression pattern, although there is partial overlap in several tissues. Prior to and during segment formation, Ct-eve1 and Ct-eve2 are both expressed in the bilaterial pair of mesoteloblasts, while Ct-eve1 is expressed in the descendant mesodermal band cells. At later stages, Ct-eve2 is expressed in the central and peripheral nervous system, and in mesoderm along the dorsal midline. In late stage larvae and adults, Ct-eve1 and Ct-eve2 are expressed in the posterior growth zone. Conclusions C. teleta eve, Pax3/7 and runt homologs all have distinct expression patterns and share expression domains with homologs from other bilaterians. None of the pair-rule orthologs examined in C. teleta exhibit segmental or pair-rule stripes of expression in the ectoderm or mesoderm, consistent with an independent origin of segmentation between annelids and arthropods.
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Affiliation(s)
- Elaine C Seaver
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui Street, Honolulu, HI, USA.
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21
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Abstract
'Evo-devo', an interdisciplinary field based on developmental biology, includes studies on the evolutionary processes leading to organ morphologies and functions. One fascinating theme in evo-devo is how fish fins evolved into tetrapod limbs. Studies by many scientists, including geneticists, mathematical biologists, and paleontologists, have led to the idea that fins and limbs are homologous organs; now it is the job of developmental biologists to integrate these data into a reliable scenario for the mechanism of fin-to-limb evolution. Here, we describe the fin-to-limb transition based on key recent developmental studies from various research fields that describe mechanisms that may underlie the development of fins, limb-like fins, and limbs.
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Affiliation(s)
- Tohru Yano
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai, Japan.
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22
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Crossing the border: molecular control of motor axon exit. Int J Mol Sci 2011; 12:8539-61. [PMID: 22272090 PMCID: PMC3257087 DOI: 10.3390/ijms12128539] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 11/05/2011] [Accepted: 11/08/2011] [Indexed: 11/23/2022] Open
Abstract
Living organisms heavily rely on the function of motor circuits for their survival and for adapting to ever-changing environments. Unique among central nervous system (CNS) neurons, motor neurons (MNs) project their axons out of the CNS. Once in the periphery, motor axons navigate along highly stereotyped trajectories, often at considerable distances from their cell bodies, to innervate appropriate muscle targets. A key decision made by pathfinding motor axons is whether to exit the CNS through dorsal or ventral motor exit points (MEPs). In contrast to the major advances made in understanding the mechanisms that regulate the specification of MN subtypes and the innervation of limb muscles, remarkably little is known about how MN axons project out of the CNS. Nevertheless, a limited number of studies, mainly in Drosophila, have identified transcription factors, and in some cases candidate downstream effector molecules, that are required for motor axons to exit the spinal cord. Notably, specialized neural crest cell derivatives, referred to as Boundary Cap (BC) cells, pre-figure and demarcate MEPs in vertebrates. Surprisingly, however, BC cells are not required for MN axon exit, but rather restrict MN cell bodies from ectopically migrating along their axons out of the CNS. Here, we describe the small set of studies that have addressed motor axon exit in Drosophila and vertebrates, and discuss our fragmentary knowledge of the mechanisms, which guide motor axons out of the CNS.
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Schulte CJ, Allen C, England SJ, Juárez-Morales JL, Lewis KE. Evx1 is required for joint formation in zebrafish fin dermoskeleton. Dev Dyn 2011; 240:1240-8. [PMID: 21509898 DOI: 10.1002/dvdy.22534] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2010] [Indexed: 11/10/2022] Open
Abstract
The transcription factor Evx1 is expressed in the joints between individual lepidotrichia (bony ray) segments and at the distal tips of the lepidotrichia in developing zebrafish fins. It is also expressed in the apical growth zone in regenerating fins. However, so far there is no functional evidence that addresses whether Evx1 is required for any aspect of fin development or regeneration. In this study, we use a novel mutation in evx1 to address this. We find that Evx1 is not required for either fin outgrowth or regeneration. All of the fins form normally in evx1 mutants, and there are no significant changes in fin length. In contrast, Evx1 is required for lepidotrichia joint formation during both fin development and regeneration. This is a very specific phenotype as both lepidotrichia hemisegment separations and lepidotrichia bifurcations still form normally in evx1 mutant fins, as do joints in the more proximal endoskeletal radials.
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Affiliation(s)
- Claus J Schulte
- Department of Physiology, Development and Neuroscience, Anatomy Building, Cambridge, UK
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Ohgo S, Itoh A, Suzuki M, Satoh A, Yokoyama H, Tamura K. Analysis of hoxa11 and hoxa13 expression during patternless limb regeneration in Xenopus. Dev Biol 2009; 338:148-57. [PMID: 19958756 DOI: 10.1016/j.ydbio.2009.11.026] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 11/19/2009] [Accepted: 11/20/2009] [Indexed: 11/29/2022]
Abstract
During limb regeneration, anuran tadpoles and urodele amphibians generate pattern-organizing, multipotent, mesenchymal blastema cells, which give rise to a replica of the lost limb including patterning in three dimensions. To facilitate the regeneration of nonregenerative limbs in other vertebrates, it is important to elucidate the molecular differences between blastema cells that can regenerate the pattern of limbs and those that cannot. In Xenopus froglet (soon after metamorphosis), an amputated limb generates blastema cells that do not produce proper patterning, resulting in a patternless regenerate, a spike, regardless of the amputation level. We found that re-expression of hoxa11 and hoxa13 in the froglet blastema is initiated although the subsequent proximal-distal patterning, including separation of the hoxa11 and hoxa13 expression domains, is disrupted. We also observed an absence of EphA4 gene expression in the froglet blastema and a failure of position-dependent cell sorting, which correlated with the altered hoxa11 and hoxa13 expression. Quantitative analysis of hoxa11 and hoxa13 expression revealed that hoxa13 transcript levels were reduced in the froglet blastema compared with the tadpole blastema. Moreover, the expression of sox9, an important regulator of chondrogenic differentiation, was detected earlier in patternless blastemas than in tadpole blastemas. These results suggest that appropriate spatial, temporal, and quantitative gene expression is necessary for pattern regeneration by blastema cells.
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Affiliation(s)
- Shiro Ohgo
- Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama Aoba-ku, Sendai 980-8578, Japan
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Suster ML, Kania A, Liao M, Asakawa K, Charron F, Kawakami K, Drapeau P. A novel conserved evx1 enhancer links spinal interneuron morphology and cis-regulation from fish to mammals. Dev Biol 2008; 325:422-33. [PMID: 18992237 DOI: 10.1016/j.ydbio.2008.10.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 09/14/2008] [Accepted: 10/02/2008] [Indexed: 10/21/2022]
Abstract
Spinal interneurons are key components of locomotor circuits, driving such diverse behaviors as swimming in fish and walking in mammals. Recent work has linked the expression of evolutionarily conserved transcription factors to key features of interneurons in diverse species, raising the possibility that these interneurons are functionally related. Consequently, the determinants of interneuron subtypes are predicted to share conserved cis-regulation in vertebrates with very different spinal cords. Here, we establish a link between cis-regulation and morphology of spinal interneurons that express the Evx1 homeodomain transcription factor from fish to mammals. Using comparative genomics, and complementary transgenic approaches, we have identified a novel enhancer of evx1, that includes two non-coding elements conserved in vertebrates. We show that pufferfish evx1 transgenes containing this enhancer direct reporter expression to a subset of spinal commissural interneurons in zebrafish embryos. Pufferfish, zebrafish and mouse evx1 downstream genomic enhancers label selectively Evx1(+) V0 commissural interneurons in chick and rat embryos. By dissecting the zebrafish evx1 enhancer, we identify a role for a 25 bp conserved cis-element in V0-specific gene expression. Our findings support the notion that spinal interneurons shared between distantly related vertebrates, have been maintained in part via the preservation of highly conserved cis-regulatory modules.
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Affiliation(s)
- Maximiliano L Suster
- Centre for Research in Neuroscience, Research Institute of the McGill University Health Centre, Montréal, Québec H3T 1J4 Canada.
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26
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Zou SM, Jiang XY. Retracted: Gene duplication and functional evolution of Hox genes in fishes. JOURNAL OF FISH BIOLOGY 2008; 73:329-354. [PMID: 20646134 DOI: 10.1111/j.1095-8649.2008.01852.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
With their power to shape animal morphology, few genes have captured the imagination of biologists as much as the evolutionarily conserved members of the Hox clusters. Hox genes encode transcription factors that play a key role in specifying the body plan in metazoans and are therefore essential in explaining patterns of evolutionary diversity. While each Hox cluster contains the same genes among the different mammalian species, this does not happen in ray-finned fish, in which both the number and organization of Hox genes and even Hox clusters are variable. Teleost fishes provide the first unambiguous support for ancient whole-genome duplication (third round) in an animal lineage. The number of genes differs in each cluster as a result of increased freedom to mutate after duplication. This has also allowed them to diverge and to adopt novel developmental roles. In this review, the authors have firstly focused on broadly outlining the duplication of Hoxgenes in fishes and discussing how comparative genomics is elucidating the molecular changes associated with the evolution of Hox genes expression and developmental function in the teleost fishes.Additional related research aspects, such as imaging of roles of microRNAs, chromatin regulation and evolutionary findings are also discussed.
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Affiliation(s)
- S M Zou
- Key Laboratory of Aquatic Genetic Resources and Aquacultural Ecosystem Certificated by the Ministry of Agriculture, Shanghai Fisheries University, Jungong Road 334, Shanghai 200090, China
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Tri-phasic expression of posterior Hox genes during development of pectoral fins in zebrafish: implications for the evolution of vertebrate paired appendages. Dev Biol 2008; 322:220-33. [PMID: 18638469 DOI: 10.1016/j.ydbio.2008.06.032] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 11/24/2022]
Abstract
During development of the limbs, Hox genes belonging to the paralogous groups 9-13 are expressed in three distinct phases, which play key roles in the segmental patterning of limb skeletons. In teleost fishes, which have a very different organization in their fin skeletons, it is not clear whether a similar patterning mechanism is at work. To determine whether Hox genes are also expressed in several distinct phases during teleost paired fin development, we re-analyzed the expression patterns of hox9-13 genes during development of pectoral fins in zebrafish. We found that, similar to tetrapod Hox genes, expression of hoxa/d genes in zebrafish pectoral fins occurs in three distinct phases, in which the most distal/third phase is correlated with the development of the most distal structure of the fin, the fin blade. Like in tetrapods, hox gene expression in zebrafish pectoral fins during the distal/third phase is dependent upon sonic hedgehog signaling (hoxa and hoxd genes) and the presence of a long-range enhancer (hoxa genes), which indicates that the regulatory mechanisms underlying tri-phasic expression of Hox genes have remained relatively unchanged during evolution. Our results suggest that, although simpler in organization, teleost fins do have a distal structure that might be considered comparable to the autopod region of limbs.
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Tamura K, Yonei-Tamura S, Yano T, Yokoyama H, Ide H. The autopod: Its formation during limb development. Dev Growth Differ 2008; 50 Suppl 1:S177-87. [DOI: 10.1111/j.1440-169x.2008.01020.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Somites are the most obvious metameric structures in the vertebrate embryo. They are mesodermal segments that form in bilateral pairs flanking the notochord and are created sequentially in an anterior to posterior sequence concomitant with the posterior growth of the trunk and tail. Zebrafish somitogenesis is regulated by a clock that causes cells in the presomitic mesoderm (PSM) to undergo cyclical activation and repression of several notch pathway genes. Coordinated oscillation among neighboring cells manifests as stripes of gene expression that pass through the cells of the PSM in a posterior to anterior direction. As axial growth continually adds new cells to the posterior tail bud, cells of the PSM become relatively less posterior. This gradual assumption of a more anterior position occurs over developmental time and constitutes part of a maturation process that governs morphological segmentation in conjunction with the clock. Segment morphogenesis involves a mesenchymal to epithelial transition as prospective border cells at the anterior end of the mesenchymal PSM adopt a polarized, columnar morphology and surround a mesenchymal core of cells. The segmental pattern influences the development of the somite derivatives such as the myotome, and the myotome reciprocates to affect the formation of segment boundaries. While somites appear to be serially homologous, there may be variation in the segmentation mechanism along the body axis. Moreover, whereas the genetic architecture of the zebrafish, mouse, and chick segmentation clocks shares many common elements, there is evidence that the gene networks have undergone independent modification during evolution.
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Affiliation(s)
- Scott A Holley
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.
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Takamatsu N, Kurosawa G, Takahashi M, Inokuma R, Tanaka M, Kanamori A, Hori H. Duplicated Abd-B class genes in medaka hoxAa and hoxAb clusters exhibit differential expression patterns in pectoral fin buds. Dev Genes Evol 2007; 217:263-73. [PMID: 17333260 DOI: 10.1007/s00427-007-0137-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Accepted: 01/25/2007] [Indexed: 11/27/2022]
Abstract
Hox genes form clusters. Invertebrates and Amphioxus have only one hox cluster, but in vertebrates, they are multiple, i.e., four in the basal teleost fish Polyodon and tetrapods (HoxA, B, C, D), but seven or eight in common teleosts. We earlier completely sequenced the entire hox gene loci in medaka fish, showing a total of 46 hox genes to be encoded in seven clusters (hoxAa, Ab, Ba, Bb, Ca, Da, Db). Among them, hoxAa, hoxAb and hoxDa clusters are presumed to be important for fin-to-limb evolution because of their key role in forelimb and pectoral fin development. In the present study, we compared genome organization and nucleotide sequences of the hoxAa and hoxAb clusters to these of tetrapod HoxA clusters, and found greater similarity in hoxAa case. We then analyzed expression of Abd-B family genes in the clusters. In the trunk, those from the hoxAa cluster, i.e., hoxA9a, hoxA10a, hoxA11a and hoxA13a, were expressed in a manner keeping the colinearity rule of the hox expression as those of tetrapods, while those from the hoxAb cluster, i.e., hoxA9b, hoxA10b, hoxA11b and hoxA13b, were not. In the pectoral fins, the hoxAa cluster was expressed in split domains and did not obey the rule. By contrast, those from the hoxAb and hoxDa clusters were expressed in a manner keeping the rule, i.e., an ancestral pattern similar to those of tetrapods. It is plausible that this differential expression of the two clusters is caused by changes occurred in global control regions after cluster duplications.
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Affiliation(s)
- Naofumi Takamatsu
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Aichi 464-8602, Japan
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Metscher BD, Takahashi K, Crow K, Amemiya C, Nonaka DF, Wagner GP. Expression ofHoxa-11andHoxa-13in the pectoral fin of a basal ray-finned fish,Polyodon spathula: implications for the origin of tetrapod limbs. Evol Dev 2005; 7:186-95. [PMID: 15876191 DOI: 10.1111/j.1525-142x.2005.05021.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Summary Paleontological and anatomical evidence suggests that the autopodium (hand or foot) is a novel feature that distinguishes limbs from fins, while the upper and lower limb (stylopod and zeugopod) are homologous to parts of the sarcopterygian paired fins. In tetrapod limb development Hoxa-11 plays a key role in differentiating the lower limb and Hoxa-13 plays a key role in differentiating the autopodium. It is thus important to determine the ancestral functions of these genes in order to understand the developmental genetic changes that led to the origin of the tetrapod autopodium. In particular it is important to understand which features of gene expression are derived in tetrapods and which are ancestral in bony fishes. To address these questions we cloned and sequenced the Hoxa-11 and Hoxa-13 genes from the North American paddlefish, Polyodon spathula, a basal ray-finned fish that has a pectoral fin morphology resembling that of primitive bony fishes ancestral to the tetrapod lineage. Sequence analysis of these genes shows that they are not orthologous to the duplicated zebrafish and fugu genes. This implies that the paddlefish has not duplicated its HoxA cluster, unlike zebrafish and fugu. The expression of Hoxa-11 and Hoxa-13 in the pectoral fins shows two main phases: an early phase in which Hoxa-11 is expressed proximally and Hoxa-13 is expressed distally, and a later phase in which Hoxa-11 and Hoxa-13 broadly overlap in the distal mesenchyme of the fin bud but are absent in the proximal fin bud. Hence the distal polarity of Hoxa-13 expression seen in tetrapods is likely to be an ancestral feature of paired appendage development. The main difference in HoxA gene expression between fin and limb development is that in tetrapods (with the exception of newts) Hoxa-11 expression is suppressed by Hoxa-13 in the distal limb bud mesenchyme. There is, however, a short period of limb bud development where Hoxa-11 and Hoxa-13 overlap similarly to the late expression seen in zebrafish and paddlefish. We conclude that the early expression pattern in tetrapods is similar to that seen in late fin development and that the local exclusion by Hoxa-13 of Hoxa-11 from the distal limb bud is a derived feature of limb developmental regulation.
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Affiliation(s)
- Brian D Metscher
- Department of Biology, University of Southern Indiana, Evansville, IN 47712, USA.
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Laurenti P, Thaëron C, Allizard F, Huysseune A, Sire JY. Cellular expression of eve1 suggests its requirement for the differentiation of the ameloblasts and for the initiation and morphogenesis of the first tooth in the zebrafish (Danio rerio). Dev Dyn 2005; 230:727-33. [PMID: 15254906 DOI: 10.1002/dvdy.20080] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
even-skipped-related (evx) genes encode homeodomain-containing transcription factors that are involved in a series of developmental processes such as posterior body patterning and neurodifferentiation. Although evx1 and evx2 were not reported to be expressed during mammalian tooth development, we present here evidence that eve1, the closest paralog of evx1 in the actinopterygian lineage, is expressed during pharyngeal tooth formation in the zebrafish, Danio rerio. We have performed whole-mount in situ hybridization on zebrafish embryos and larvae ranging from 24 to 192 hours postfertilization (hpf). A detailed analysis of serial sections through the pharyngeal region of whole-mount hybridized and control specimens indicates that only dental epithelial cells express eve1. eve1 transcription was activated at 48 hpf, in the placode of the first tooth (i.e., the initiation site of tooth 4V(1)), and maintained in the dental epithelium throughout morphogenesis. Then, by 72 hpf, eve1 expression was restricted to the differentiating ameloblasts of the enamel organ during early differentiation stage, and this expression decreased as soon as matrix was deposited. In subsequent primary teeth (3 V(1) and 5 V(1)) as well as in their successors (replacement teeth 4V(2), 3V(2), and 5V(2)), eve1 expression was restricted to the differentiating ameloblasts and, again, disappeared when matrix was deposited. Therefore, in the zebrafish, eve1 expression in the pharyngeal region is correlated with two key steps of tooth development: initiation and morphogenesis of the first tooth, and ameloblast differentiation of all developing teeth.
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Leung AYH, Mendenhall EM, Kwan TTF, Liang R, Eckfeldt C, Chen E, Hammerschmidt M, Grindley S, Ekker SC, Verfaillie CM. Characterization of expanded intermediate cell mass in zebrafish chordin morphant embryos. Dev Biol 2005; 277:235-54. [PMID: 15572152 DOI: 10.1016/j.ydbio.2004.09.032] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Revised: 08/30/2004] [Accepted: 09/24/2004] [Indexed: 11/30/2022]
Abstract
We investigated the mechanisms of intermediate cell mass (ICM) expansion in zebrafish chordin (Chd) morphant embryos and examined the role of BMPs in relation to this phenotype. At 24 h post-fertilization (hpf), the expanded ICM of embryos injected with chd morpholino (MO) (ChdMO embryos) contained a monotonous population of hematopoietic progenitors. In situ hybridization showed that hematopoietic transcription factors were ubiquitously expressed in the ICM whereas vascular gene expression was confined to the periphery. BMP4 (but not BMP2b or 7) and smad5 mRNA were ectopically expressed in the ChdMO ICM. At 48 hpf, monocytic cells were evident in both the ICM and circulation of ChdMO but not WT embryos. While injection of BMP4 MO had no effect on WT hematopoiesis, co-injecting BMP4 with chd MOs significantly reduced ICM expansion. Microarray studies revealed a number of genes that were differentially expressed in ChdMO and WT embryos and their roles in hematopoiesis has yet to be determined. In conclusion, the expanded ICM in ChdMO embryos represented an expansion of embryonic hematopoiesis that was skewed towards a monocytic lineage. BMP4, but not BMP2b or 7, was involved in this process. The results provide ground for further research into the mechanisms of embryonic hematopoietic cell expansion.
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Affiliation(s)
- Anskar Y H Leung
- Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
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Thummel R, Li L, Tanase C, Sarras MP, Godwin AR. Differences in expression pattern and function between zebrafish hoxc13 orthologs: recruitment of Hoxc13b into an early embryonic role. Dev Biol 2004; 274:318-33. [PMID: 15385162 DOI: 10.1016/j.ydbio.2004.07.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 06/18/2004] [Accepted: 07/06/2004] [Indexed: 01/17/2023]
Abstract
Vertebrate Hox genes are generally believed to initiate expression at the primitive streak or early neural plate stages. The timing and spatial restrictions of the Hox expression patterns during these stages correlate well with their demonstrated role in axial patterning. Here we demonstrate that one zebrafish hoxc13 ortholog, hoxc13a, has an expression pattern in the developing tail bud that is consistent with the gene playing a role in axial patterning. However, the second hoxc13 ortholog, hoxc13b, is maternally expressed and is detectable in every cell of early cleavage embryos through gastrulae. In addition, both transcript and protein are detectable at these stages. At 19 h post fertilization (hpf), hoxc13b expression is up-regulated in the tail bud, becoming restricted to the tail bud by 24 hpf. Importantly, by 24 hpf, hoxc13b morphants show a specific developmental delay, which can be rescued by co-injecting synthetic capped hoxc13a or hoxc13b message. These data suggest some functional divergence due to altered expression patterns of the two hoxc13 orthologs after duplication. Further characterization of the hoxc13b morphant delay reveals that it is biphasic in nature, with the first phase of the delay occurring before gastrulation, suggesting a new role for vertebrate Hox genes before their conserved role in axial patterning. The extent of the delay does not change through 20 hpf; however, an additional delay emerges at this time. Notably, this second phase of the delay correlates with hoxc13b expression pattern becoming restricted to the tail bud.
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Affiliation(s)
- Ryan Thummel
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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35
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Géraudie J, Borday Birraux V. Posterior hoxa genes expression during zebrafish bony fin ray development and regeneration suggests their involvement in scleroblast differentiation. Dev Genes Evol 2003; 213:182-6. [PMID: 12684773 DOI: 10.1007/s00427-003-0307-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2002] [Accepted: 02/10/2003] [Indexed: 10/25/2022]
Abstract
Expression of two zebrafish developmental posterior hoxa genes, hoxa11b and hoxa13b, was studied by in situ hybridization during pectoral and caudal fin development and regeneration. Expression was restricted to cells of the bony rays region. During fin development, molecular cytological analysis revealed that a subpopulation of mesenchymal cells expressed these two hoxa genes during their early differentiation in the subapical region of the developing ray. These cells were identified as differentiating dermal bone making cells (scleroblasts). During fin regeneration, hoxa11b and hoxa13b genes are both induced in undifferentiated cells of the distalmost blastema region (DMB) and the proliferating zone (PZ) and later in differentiating bone-forming cells. In addition, the transient regionalization of the hoxa13b expression pattern in differentiated bone-forming cells along the proximodistal axis of the regenerating ray suggests that hoxa13b could participate in ray patterning. This study is the first to establish a correlation between hoxa gene expression and dermal bone cell differentiation.
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Affiliation(s)
- Jacqueline Géraudie
- Laboratoire de Biologie du Développement, Université Paris 7-Denis Diderot, Paris, France.
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36
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Avaron F, Thaëron-Antono C, Beck CW, Borday-Birraux V, Géraudie J, Casane D, Laurenti P. Comparison of even-skipped related gene expression pattern in vertebrates shows an association between expression domain loss and modification of selective constraints on sequences. Evol Dev 2003; 5:145-56. [PMID: 12622731 DOI: 10.1046/j.1525-142x.2003.03021.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The even-skipped related genes (evx) encode homeodomain-containing transcription factors that play key roles in body patterning and neurogenesis in a wide array of Eumetazoa species. It is thought that the genome of the last common ancestor of Chordata contained a unique evx gene linked to a unique ancestral Hox complex. During subsequent evolution, two rounds of whole genome duplication followed by individual gene losses gave rise to three paralogs: evx1, evx2, and eve1. Then, eve1 was maintained in Actinopterygii lineage but not in Tetrapoda. To explain this discrepancy, we examined the expression patterns of the evx1 homologue, Xhox3, in Xenopus laevis and that of evx1 and eve1 in Danio rerio. We show here that Xhox3 is expressed in a manner that closely reflects the inferred expression pattern of the evx1 gene in the last common ancestor of Vertebrata (i.e., in gastrula, the central nervous system, the posterior gut, and the tip of the growing tail). Zebrafish evx1 and Xenopus Xhox3 are expressed in homologous cell lineages of the central nervous system and of the posterior gut, but evx1 was undetectable in the gastrula and the tail bud. Strikingly, eve1 is the only evx gene of zebrafish to be expressed in these two latter regions. Thus, the ancestral expression pattern of evx1 in vertebrates appears to have been distributed between evx1 and eve1 in zebrafish. We propose that evx1 and eve1 underwent a complementary loss of expression domain in zebrafish that allowed the maintenance of the two paralogs in accordance with the duplication-degeneration-complementation model. It is important to note that, in zebrafish, Evx1 and Eve1 have lost most of the protein domain upstream of the homeodomain. In addition, Eve1 has accumulated substitutions in positions that are highly conserved in all other Evx proteins. Thus, the reduction of the expression domain of both evx1 and eve1 in zebrafish appears to be associated with the modification of constraints on the protein sequences, allowing the shortening of both genes and an accelerated substitution rate in eve1.
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Affiliation(s)
- Fabien Avaron
- Laboratoire de Biologie du Développement, Université de Paris 7, case courrier 7077, 2 place Jussieu, 75251 Paris cedex 5, France
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Yokoi H, Nishimatsu A, Ozato K, Yoda K. Cloning and embryonic expression of six wnt genes in the medaka (Oryzias latipes) with special reference to expression of wnt5a in the pectoral fin buds. Dev Growth Differ 2003; 45:51-61. [PMID: 12630946 DOI: 10.1046/j.1440-169x.2003.00674.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
WNTs are secreted signaling molecules which control cell differentiation and proliferation. They are known to play essential roles in various developmental processes. Wnt genes have been identified in a variety of animals, and it has been shown that their amino acid sequences are highly conserved throughout evolution. To investigate the role of wnt genes during fish development from the evolutionary viewpoint, six medaka wnt genes (wnt4, wnt5a, wnt6, wnt7b, wnt8b and wnt8-like) were isolated and their embryonic expression was examined. These wnt genes were expressed in various tissues during embryonic development, and most of their expression patterns were conserved or comparable to those of other vertebrates. Thus, these wnt genes may be useful as molecular markers to investigate development and organogenesis using the medaka. Focus was on wnt5a, which was expressed in the pectoral fin buds, because its expression pattern was particularly comparable to that in tetrapod limbs. Its detailed expression pattern was further examined during pectoral fin bud development. The conservation and diversification of Wnt5a expression through the evolutionary transition from fish fins to tetrapod limbs is discussed.
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Affiliation(s)
- Hayato Yokoi
- Division of Biological Science, Graduate School of Science, Nagoya University, Japan.
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38
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Kmita M, Tarchini B, Duboule D, Hérault Y. Evolutionary conserved sequences are required for the insulation of the vertebrate Hoxd complex in neural cells. Development 2002; 129:5521-8. [PMID: 12403721 DOI: 10.1242/dev.00151] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transcriptional regulation of vertebrate Hox genes involves enhancer sequences located either inside or outside the gene clusters. In the mouse Hoxd complex, for example, series of contiguous genes are coordinately controlled by regulatory sequences located at remote distances. However, in different cellular contexts, Hox genes may have to be insulated from undesirable external regulatory influences to prevent ectopic gene activation, a situation that would likely be detrimental to the developing embryo. We show the presence of an insulator activity, at one extremity of the Hoxd complex, that is composed of at least two distinct DNA elements, one of which is conserved throughout vertebrate species. However, deletion of this element on its own did not detectably affect Hoxd gene expression, unless another DNA fragment located nearby was removed in cis. These results suggest that insulation of this important gene cluster relies, at least in part, upon a sequence-specific mechanism that displays some redundancy.
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Affiliation(s)
- Marie Kmita
- Department of Zoology and Animal Biology, University of Geneva, Sciences III, Quai Ernest Ansermet 30, Switzerland
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39
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Fujioka M, Yusibova GL, Patel NH, Brown SJ, Jaynes JB. The repressor activity of Even-skipped is highly conserved, and is sufficient to activate engrailed and to regulate both the spacing and stability of parasegment boundaries. Development 2002; 129:4411-21. [PMID: 12223400 PMCID: PMC2709299 DOI: 10.1242/dev.129.19.4411] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During segmentation of the Drosophila embryo, even skipped is required to activate engrailed stripes and to organize odd-numbered parasegments. A 16 kb transgene containing the even skipped coding region can rescue normal engrailed expression, as well as all other aspects of segmentation, in even skipped null mutants. To better understand its mechanism of action, we functionally dissected the Even-skipped protein in the context of this transgene. We found that Even-skipped utilizes two repressor domains to carry out its function. Each of these domains can function autonomously in embryos when fused with the Gal4 DNA-binding domain. A chimeric protein consisting only of the Engrailed repressor domain and the Even-skipped homeodomain, but not the homeodomain alone, was able to restore function, indicating that the repression of target genes is sufficient for even skipped function at the blastoderm stage, while the homeodomain is sufficient to recognize those target genes. When Drosophila Even skipped was replaced by its homologs from other species, including a mouse homolog, they could provide substantial function, indicating that these proteins can recognize similar target sites and also provide repressor activity. Using this rescue system, we show that broad, early even skipped stripes are sufficient for activation of both odd- and even-numbered engrailed stripes. Furthermore, these ‘unrefined’ stripes organize odd-numbered parasegments in a dose-dependent manner, while the refined, late stripes, which coincide cell-for-cell with parasegment boundaries, are required to ensure the stability of the boundaries.
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Affiliation(s)
- Miki Fujioka
- Department of Microbiology and Immunology, Thomas Jefferson University, JAH490, Philadelphia, PA 19107, USA
| | - Galina L. Yusibova
- Department of Microbiology and Immunology, Thomas Jefferson University, JAH490, Philadelphia, PA 19107, USA
| | - Nipam H. Patel
- Department of Anatomy and Organismal Biology and HHMI, University of Chicago, MC1028, AMBN101, 5841 South Maryland Avenue, Chicago, IL 60637, USA
| | - Susan J. Brown
- Division of Biology, Kansas State University, Manhattan, Kansas 66506, USA
| | - James B. Jaynes
- Department of Microbiology and Immunology, Thomas Jefferson University, JAH490, Philadelphia, PA 19107, USA
- Author for correspondence (e-mail: )
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40
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Morin-Kensicki EM, Melancon E, Eisen JS. Segmental relationship between somites and vertebral column in zebrafish. Development 2002; 129:3851-60. [PMID: 12135923 DOI: 10.1242/dev.129.16.3851] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The segmental heritage of all vertebrates is evident in the character of the vertebral column. And yet, the extent to which direct translation of pattern from the somitic mesoderm and de novo cell and tissue interactions pattern the vertebral column remains a fundamental, unresolved issue. The elements of vertebral column pattern under debate include both segmental pattern and anteroposterior regional specificity. Understanding how vertebral segmentation and anteroposterior positional identity are patterned requires understanding vertebral column cellular and developmental biology. In this study, we characterized alignment of somites and vertebrae, distribution of individual sclerotome progeny along the anteroposterior axis and development of the axial skeleton in zebrafish. Our clonal analysis of zebrafish sclerotome shows that anterior and posterior somite domains are not lineage-restricted compartments with respect to distribution along the anteroposterior axis but support a ‘leaky’ resegmentation in development from somite to vertebral column. Alignment of somites with vertebrae suggests that the first two somites do not contribute to the vertebral column. Characterization of vertebral column development allowed examination of the relationship between vertebral formula and expression patterns of zebrafish Hox genes. Our results support co-localization of the anterior expression boundaries of zebrafish hoxc6 homologs with a cervical/thoracic transition and also suggest Hox-independent patterning of regionally specific posterior vertebrae.
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41
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Perriton CL, Powles N, Chiang C, Maconochie MK, Cohn MJ. Sonic hedgehog signaling from the urethral epithelium controls external genital development. Dev Biol 2002; 247:26-46. [PMID: 12074550 DOI: 10.1006/dbio.2002.0668] [Citation(s) in RCA: 213] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
External genital development begins with formation of paired genital swellings, which develop into the genital tubercle. Proximodistal outgrowth and axial patterning of the genital tubercle are coordinated to give rise to the penis or clitoris. The genital tubercle consists of lateral plate mesoderm, surface ectoderm, and endodermal urethral epithelium derived from the urogenital sinus. We have investigated the molecular control of external genital development in the mouse embryo. Previous work has shown that the genital tubercle has polarizing activity, but the precise location of this activity within the tubercle is unknown. We reasoned that if the tubercle itself is patterned by a specialized signaling region, then polarizing activity may be restricted to a subset of cells. Transplantation of urethral epithelium, but not genital mesenchyme, to chick limbs results in mirror-image duplication of the digits. Moreover, when grafted to chick limbs, the urethral plate orchestrates morphogenetic movements normally associated with external genital development. Signaling activity is therefore restricted to urethral plate cells. Before and during normal genital tubercle outgrowth, urethral plate epithelium expresses Sonic hedgehog (Shh). In mice with a targeted deletion of Shh, external genitalia are absent. Genital swellings are initiated, but outgrowth is not maintained. In the absence of Shh signaling, Fgf8, Bmp2, Bmp4, Fgf10, and Wnt5a are downregulated, and apoptosis is enhanced in the genitalia. These results identify the urethral epithelium as a signaling center of the genital tubercle, and demonstrate that Shh from the urethral epithelium is required for outgrowth, patterning, and cell survival in the developing external genitalia.
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Affiliation(s)
- Claire L Perriton
- Division of Zoology, University of Reading, Whiteknights, United Kingdom
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42
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Ferrier DE, Minguillón C, Cebrián C, Garcia-Fernàndez J. Amphioxus Evx genes: implications for the evolution of the Midbrain-Hindbrain Boundary and the chordate tailbud. Dev Biol 2001; 237:270-81. [PMID: 11543613 DOI: 10.1006/dbio.2001.0375] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Evx genes are widely used in animal development. In vertebrates they are crucial in gastrulation, neurogenesis, appendage development and tailbud formation, whilst in protostomes they are involved in gastrulation and neurogenesis, as well as segmentation at least in Drosophila. We have cloned the Evx genes of amphioxus (Branchiostoma floridae), and analysed their expression to understand how the functions of Evx have evolved between invertebrates and vertebrates, and in particular at the origin of chordates and during their subsequent evolution. Amphioxus has two Evx genes (AmphiEvxA and AmphiEvxB) which are genomically linked. AmphiEvxA is prototypical to the vertebrate Evx1 and Evx2 genes with respect to its sequence and expression, whilst AmphiEvxB is very divergent. Mapping the expression of AmphiEvxA onto a phylogeny shows that a role in gastrulation, dorsal-ventral patterning and neurogenesis is probably retained throughout bilaterian animals. AmphiEvxA expression during tailbud development implies a role for Evx throughout the chordates in this process, whilst lack of expression at the homologous region to the vertebrate Midbrain-Hindbrain Boundary (MHB) is consistent with the elaboration of the full organiser properties of this region being a vertebrate innovation.
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Affiliation(s)
- D E Ferrier
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain
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43
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Borday V, Thaëron C, Avaron F, Brulfert A, Casane D, Laurenti P, Géraudie J. evx1 transcription in bony fin rays segment boundaries leads to a reiterated pattern during zebrafish fin development and regeneration. Dev Dyn 2001; 220:91-8. [PMID: 11169842 DOI: 10.1002/1097-0177(2000)9999:9999<::aid-dvdy1091>3.0.co;2-j] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The dermoskeleton of zebrafish fins is composed of actinotrichia and segmented bony rays, or lepidotrichia, which grow by successive addition of distal segments. The present study shows that evx1, a new zebrafish even-skipped related gene (Thaëron et al., 2000) displays during bony ray morphogenesis, a unique repetitive expression pattern along the proximodistal axis of the fin. Whole-mount in situ hybridization performed on larvae and adult regenerating fins show that evx1 signal appears as parallel dash lines crossing the width of each developing and regenerating rays, in a ladder-like fashion. Cytological studies show that a subpopulation of bone forming cells (scleroblasts) expresses evx1 at the level of the joint between two adjacent segments except in the apical part of the differentiating ray where evx1 expression precedes the formation of the joint. This distal transcription is turned on again only when the latest differentiating segment reached its final size and might label the putative next segment boundary. This suggests the existence of a molecular mechanism controlling the periodic expression of evx1 which could be involved in the establishment of segment boundaries during fin ray morphogenesis, and could play a key role during dermal skeleton patterning.
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Affiliation(s)
- V Borday
- Laboratoire de Biologie du Développement, Université Paris 7-Denis Diderot, case 7077, 2 Place Jussieu, 75251 Paris cedex 5, France
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44
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Capdevila J, Izpisúa Belmonte JC. Perspectives on the evolutionary origin of tetrapod limbs. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2000; 288:287-303. [PMID: 11144278 DOI: 10.1002/1097-010x(20001215)288:4<287::aid-jez2>3.0.co;2-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The study of the origin and evolution of the tetrapod limb has benefited enormously from the confluence of molecular and paleontological data. In the last two decades, our knowledge of the basic molecular mechanisms that control limb development has grown exponentially, and developmental biologists now have the possibility of combining molecular data with many available descriptions of the fossil record of vertebrate fins and limbs. This synthesis of developmental and evolutionary biology has the potential to unveil the sequence of molecular changes that culminated in the adoption of the basic tetrapod limb plan.
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Affiliation(s)
- J Capdevila
- The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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45
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Thaëron C, Avaron F, Casane D, Borday V, Thisse B, Thisse C, Boulekbache H, Laurenti P. Zebrafish evx1 is dynamically expressed during embryogenesis in subsets of interneurones, posterior gut and urogenital system. Mech Dev 2000; 99:167-72. [PMID: 11091087 DOI: 10.1016/s0925-4773(00)00473-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The even-skipped-related homeobox genes (evx) are widely distributed through animal kingdom and are thought to play key role in posterior body patterning and neurogenesis. We have cloned and analyzed the expression of evx1 in zebrafish (see also Borday et al. (Dev. Dyn. 220 (2001) in press) which displays a dynamic and restricted expression pattern during neurogenesis. In spinal cord, rhombencephalon, and epiphysis, evx1 is expressed in several subsets of emerging interneurones prior to their axonal outgrowth, identified as primary interneurones and a subset of Pax2.1(+) commissural interneurones. In the hindbrain, evx1 is expressed in reticulospinal interneurones of rhombomeres 5 and 6 as well as in rhombomere 7 interneurones. The latest emerging evx1(+) interneurones in the hindbrain correspond to commissural interneurones. evx1 is also dynamically transcribed during the formation of the posterior gut and the uro-genital system in mesenchymal cells that border the pronephric ducts, the wall of the pronephric duct, and later in the posterior gut and the wall of the uro-genital opening. In larvae, the ano-rectal epithelium and the muscular layer that surrounds the analia-genitalia region remain stained up to 27 days. In contrast other vertebrates, evx1displays no early nor caudal expression in zebrafish.
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Affiliation(s)
- C Thaëron
- Laboratoire de Biologie du Développement, EA 296, Université de Paris 7, case courrier 7077, 2 place Jussieu, 75251 cedex 5, Paris, France
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46
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Labudova O, Kitzmueller E, Rink H, Cairns N, Lubec G. Gene expression in fetal Down syndrome brain as revealed by subtractive hybridization. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2000; 57:125-36. [PMID: 10666672 DOI: 10.1007/978-3-7091-6380-1_8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Information on gene expression in brain of patients with Down Syndrome (DS, trisomy 21) is limited and molecular biological research is focussing on mapping and sequencing chromosome 21. The information on gene expression in DS available follows the current concept of a gene dosage effect due to a third copy of chromosome 21 claiming overexpression of genes encoded on this chromosome. Based upon the availability of fetal brain and recent technology of gene hunting, we decided to use subtractive hybridization to evaluate differences in gene expression between DS and control brains. Subtractive hybridization was applied on two fetal brains with DS and two age and sex matched controls, 23rd week of gestation, and mRNA steady state levels were evaluated generating a subtractive library. Subtracted sequences were identified by gene bank and assigned by alignments to individual genes. We found a series of up- and downregulated sequences consisting of chromosomal transcripts, enzymes of intermediary metabolism, hormones, transporters/channels and transcription factors (TFs). We show that trisomy 21 or aneuploidy leads to the deterioration of gene expression and the derangement of transcripts described describes the involvement of chromosomes other than chromosome 21, explains impairment of transport, carriers, channels, signaling, known metabolic and hormones imbalances. The dys-coordinated expression of transcription factors including homeobox genes, POU-domain TFs, helix-loop-helix-motifs, LIM domain containing TFs, leucine zippers, forkhead genes, maybe of pathophysiological significance for abnormal brain development and wiring found in patients with DS. This is the first description of the concomitant expression of a large series of sequences indicating disruption of the concerted action of genes in that disorder.
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Affiliation(s)
- O Labudova
- Department of Pediatrics, University of Vienna, Austria
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47
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Durbin L, Sordino P, Barrios A, Gering M, Thisse C, Thisse B, Brennan C, Green A, Wilson S, Holder N. Anteroposterior patterning is required within segments for somite boundary formation in developing zebrafish. Development 2000; 127:1703-13. [PMID: 10725246 DOI: 10.1242/dev.127.8.1703] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Somite formation involves the establishment of a segmental prepattern in the presomitic mesoderm, anteroposterior patterning of each segmental primordium and formation of boundaries between adjacent segments. How these events are co-ordinated remains uncertain. In this study, analysis of expression of zebrafish mesp-a reveals that each segment acquires anteroposterior regionalisation when located in the anterior presomitic mesoderm. Thus anteroposterior patterning is occurring after the establishment of a segmental prepattern in the paraxial mesoderm and prior to somite boundary formation. Zebrafish fss(−), bea(−), des(−) and aei(−) embryos all fail to form somites, yet we demonstrate that a segmental prepattern is established in the presomitic mesoderm of all these mutants and hox gene expression shows that overall anteroposterior patterning of the mesoderm is also normal. However, analysis of various molecular markers reveals that anteroposterior regionalisation within each segment is disturbed in the mutants. In fss(−), there is a loss of anterior segment markers, such that all segments appear posteriorized, whereas in bea(−), des(−) and aei(−), anterior and posterior markers are expressed throughout each segment. Since somite formation is disrupted in these mutants, correct anteroposterior patterning within segments may be a prerequisite for somite boundary formation. In support of this hypothesis, we show that it is possible to rescue boundary formation in fss(−) through the ectopic expression of EphA4, an anterior segment marker, in the paraxial mesoderm. These observations indicate that a key consequence of the anteroposterior regionalisation of segments may be the induction of Eph and ephrin expression at segment interfaces and that Eph/ephrin signalling subsequently contributes to the formation of somite boundaries.
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Affiliation(s)
- L Durbin
- Department of Anatomy and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
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48
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de Martino S, Yan YL, Jowett T, Postlethwait JH, Varga ZM, Ashworth A, Austin CA. Expression of sox11 gene duplicates in zebrafish suggests the reciprocal loss of ancestral gene expression patterns in development. Dev Dyn 2000; 217:279-92. [PMID: 10741422 DOI: 10.1002/(sici)1097-0177(200003)217:3<279::aid-dvdy6>3.0.co;2-s] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
To investigate the role of sox genes in vertebrate development, we have isolated sox11 from zebrafish (Danio rerio). Two distinct classes of sox11-related cDNAs were identified, sox11a and sox11b. The predicted protein sequences shared 75% identity. In a gene phylogeny, both sox11a and sox11b cluster with human, mouse, chick, and Xenopus Sox11, indicating that zebrafish, like Xenopus, has two orthologues of tetrapod Sox11. The work reported here investigates the evolutionary origin of these two gene duplicates and the consequences of their duplication for development. The sox11a and sox11b genes map to linkage groups 17 and 20, respectively, together with other loci whose orthologues are syntenic with human SOX11, suggesting that during the fish lineage, a large chromosome region sharing conserved syntenies with mammals has become duplicated. Studies in mouse and chick have shown that Sox11 is expressed in the central nervous system during development. Expression patterns of zebrafish sox11a and sox11b confirm that they are expressed in the developing nervous system, including the forebrain, midbrain, hindbrain, eyes, and ears from an early stage. Other sites of expression include the fin buds and somites. The two sox genes, sox11a and sox11b, are expressed in both overlapping and distinct sites. Their expression patterns suggest that sox11a and sox11b may share the developmental domains of the single Sox11 gene present in mouse and chick. For example, zebrafish sox11a is expressed in the anterior somites, and zebrafish sox11b is expressed in the posterior somites, but the single Sox11 gene of mouse is expressed in all the somites. Thus, the zebrafish duplicate genes appear to have reciprocally lost expression domains present in the sox11 gene of the last common ancestor of tetrapods and zebrafish. This splitting of the roles of Sox11 between two paralogues suggests that regulatory elements governing the expression of the sox11 gene in the common ancestor of zebrafish and tetrapods may have been reciprocally mutated in the zebrafish gene duplicates. This is consistent with duplicate gene evolution via a duplication-degeneration-complementation process.
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Affiliation(s)
- S de Martino
- School of Biochemistry and Genetics, The Medical School, University of Newcastle, Newcastle-upon-Tyne, United Kingdom
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49
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Mechanisms of Hox gene colinearity: transposition of the anterior Hoxb1 gene into the posterior HoxD complex. Genes Dev 2000. [DOI: 10.1101/gad.14.2.198] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Transposition of Hoxd genes to a more posterior (5′) location within the HoxD complex suggested that colinearity in the expression of these genes was due, in part, to the existence of a silencing mechanism originating at the 5′ end of the cluster and extending towards the 3′ direction. To assess the strength and specificity of this repression, as well as to challenge available models on colinearity, we inserted a Hoxb1/lacZtransgene within the posterior HoxD complex, thereby reconstructing a cluster with a copy of the most anterior gene inserted at the most posterior position. Analysis of Hoxb1 expression after ectopic relocation revealed that Hoxb1-specific activity in the fourth rhombomere was totally abolished. Treatment with retinoic acid, or subsequent relocations toward more 3′ positions in theHoxD complex, did not release this silencing in hindbrain cells. In contrast, however, early and anterior transgene expression in the mesoderm was unexpectedly not suppressed. Furthermore, the transgene induced a transient ectopic activation of the neighboringHoxd13 gene, without affecting other genes of the complex. Such a local and transient break in colinearity was also observed after transposition of the Hoxd9/lacZ reporter gene, indicating that it may be a general property of these transgenes when transposed at an ectopic location. These results are discussed in the context of existing models, which account for colinear activation of vertebrate Hox genes.
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50
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Abstract
Vertebrate Hox genes are activated in a spatiotemporal sequence that reflects their clustered organization. While this colinear relationship is a property of most metazoans with an anterior to posterior polarity, the underlying molecular mechanisms are unknown. Previous work suggested that Hox genes were made progressively available for transcription in the course of gastrulation, implying the existence of an element capable of initiating a repressive conformation, subsequently relieved from the clusters sequentially. We searched for this element by combining a genomic walk with successive transgene insertions upstream of the HoxD complex followed by a series of deletions. The largest deficiency induced posterior homeotic transformations coincidentally with an earlier activation of Hoxd genes. These data suggest that a regulatory element located upstream of the complex is necessary for setting up the early pattern of Hox gene colinear activation.
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Affiliation(s)
- T Kondo
- Department of Zoology and Animal Biology, University of Geneva, Sciences III, Switzerland
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