1
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Smith FW, Game M, Mapalo MA, Chavarria RA, Harrison TR, Janssen R. Developmental and genomic insight into the origin of the tardigrade body plan. Evol Dev 2024; 26:e12457. [PMID: 37721221 DOI: 10.1111/ede.12457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023]
Abstract
Tardigrada is an ancient lineage of miniaturized animals. As an outgroup of the well-studied Arthropoda and Onychophora, studies of tardigrades hold the potential to reveal important insights into body plan evolution in Panarthropoda. Previous studies have revealed interesting facets of tardigrade development and genomics that suggest that a highly compact body plan is a derived condition of this lineage, rather than it representing an ancestral state of Panarthropoda. This conclusion was based on studies of several species from Eutardigrada. We review these studies and expand on them by analyzing the publicly available genome and transcriptome assemblies of Echiniscus testudo, a representative of Heterotardigrada. These new analyses allow us to phylogenetically reconstruct important features of genome evolution in Tardigrada. We use available data from tardigrades to interrogate several recent models of body plan evolution in Panarthropoda. Although anterior segments of panarthropods are highly diverse in terms of anatomy and development, both within individuals and between species, we conclude that a simple one-to-one alignment of anterior segments across Panarthropoda is the best available model of segmental homology. In addition to providing important insight into body plan diversification within Panarthropoda, we speculate that studies of tardigrades may reveal generalizable pathways to miniaturization.
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Affiliation(s)
- Frank W Smith
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Mandy Game
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Marc A Mapalo
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Raul A Chavarria
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Taylor R Harrison
- Biology Department, University of North Florida, Jacksonville, Florida, USA
| | - Ralf Janssen
- Department of Earth Sciences, Palaeobiology, Uppsala University, Uppsala, Sweden
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2
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Rallis J, Pavlopoulos A. Cellular basis of limb morphogenesis. CURRENT OPINION IN INSECT SCIENCE 2022; 50:100887. [PMID: 35150918 DOI: 10.1016/j.cois.2022.100887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
How the size and shape of developing tissues is encoded in the genome has been a longstanding riddle for biologists. Constituent cells integrate several genetic and mechanical signals to decide whether to divide, die, change shape or position. We review here how morphogenetic cell behaviors contribute to leg formation from imaginal disc epithelia in the insect Drosophila melanogaster, as well as to direct embryonic limb outgrowths in the non-insect pancrustacean Parhyale hawaiensis. Considering the deep conservation of developmental programs for limb patterning among arthropods and other bilaterians, moving forward, it will be exciting to see how these genetic similarities reflect at the cellular and tissue mechanics level.
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Affiliation(s)
- John Rallis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 70013 Heraklion, Crete, Greece; Department of Biology, University of Crete, 70013 Heraklion, Crete, Greece
| | - Anastasios Pavlopoulos
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, 70013 Heraklion, Crete, Greece.
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3
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Neal S, McCulloch KJ, Napoli FR, Daly CM, Coleman JH, Koenig KM. Co-option of the limb patterning program in cephalopod eye development. BMC Biol 2022; 20:1. [PMID: 34983491 PMCID: PMC8728989 DOI: 10.1186/s12915-021-01182-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/02/2021] [Indexed: 12/01/2022] Open
Abstract
Background Across the Metazoa, similar genetic programs are found in the development of analogous, independently evolved, morphological features. The functional significance of this reuse and the underlying mechanisms of co-option remain unclear. Cephalopods have evolved a highly acute visual system with a cup-shaped retina and a novel refractive lens in the anterior, important for a number of sophisticated behaviors including predation, mating, and camouflage. Almost nothing is known about the molecular-genetics of lens development in the cephalopod. Results Here we identify the co-option of the canonical bilaterian limb patterning program during cephalopod lens development, a functionally unrelated structure. We show radial expression of transcription factors SP6-9/sp1, Dlx/dll, Pbx/exd, Meis/hth, and a Prdl homolog in the squid Doryteuthis pealeii, similar to expression required in Drosophila limb development. We assess the role of Wnt signaling in the cephalopod lens, a positive regulator in the developing Drosophila limb, and find the regulatory relationship reversed, with ectopic Wnt signaling leading to lens loss. Conclusion This regulatory divergence suggests that duplication of SP6-9 in cephalopods may mediate the co-option of the limb patterning program. Thus, our study suggests that this program could perform a more universal developmental function in radial patterning and highlights how canonical genetic programs are repurposed in novel structures. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01182-2.
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Affiliation(s)
- Stephanie Neal
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, 02138, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Kyle J McCulloch
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, 02138, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Francesca R Napoli
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, 02138, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Christina M Daly
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, 02138, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - James H Coleman
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, 02138, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Kristen M Koenig
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA, 02138, USA. .,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
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4
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Laurichesse Q, Moucaud B, Laddada L, Renaud Y, Jagla K, Soler C. Transcriptomic and Genetic Analyses Identify the Krüppel-Like Factor Dar1 as a New Regulator of Tube-Shaped Long Tendon Development. Front Cell Dev Biol 2021; 9:747563. [PMID: 34977007 PMCID: PMC8716952 DOI: 10.3389/fcell.2021.747563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/29/2021] [Indexed: 11/13/2022] Open
Abstract
To ensure locomotion and body stability, the active role of muscle contractions relies on a stereotyped muscle pattern set in place during development. This muscle patterning requires a precise assembly of the muscle fibers with the skeleton via a specialized connective tissue, the tendon. Like in vertebrate limbs, Drosophila leg muscles make connections with specific long tendons that extend through different segments. During the leg disc development, cell precursors of long tendons rearrange and collectively migrate to form a tube-shaped structure. A specific developmental program underlies this unique feature of tendon-like cells in the Drosophila model. We provide for the first time a transcriptomic profile of leg tendon precursors through fluorescence-based cell sorting. From promising candidates, we identified the Krüppel-like factor Dar1 as a critical actor of leg tendon development. Specifically expressed in the leg tendon precursors, loss of dar1 disrupts actin-rich filopodia formation and tendon elongation. Our findings show that Dar1 acts downstream of Stripe and is required to set up the correct number of tendon progenitors.
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5
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Richardson AE, Cheng J, Johnston R, Kennaway R, Conlon BR, Rebocho AB, Kong H, Scanlon MJ, Hake S, Coen E. Evolution of the grass leaf by primordium extension and petiole-lamina remodeling. Science 2021; 374:1377-1381. [PMID: 34882477 DOI: 10.1126/science.abf9407] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- A E Richardson
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.,Agricultural Research Service/US Department of Agriculture Plant Gene Expression Center, Albany, CA 94710, USA.,Institute of Molecular Plant Science, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - J Cheng
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.,State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - R Johnston
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.,The Elshire Group Limited, Palmerston North 4472, New Zealand
| | - R Kennaway
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - B R Conlon
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - A B Rebocho
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - H Kong
- State Key Laboratory of Systematic and Evolutionary Botany, CAS Center for Excellence in Molecular Plant Sciences, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - M J Scanlon
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA
| | - S Hake
- Agricultural Research Service/US Department of Agriculture Plant Gene Expression Center, Albany, CA 94710, USA
| | - E Coen
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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6
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Ruiz-Losada M, Pérez-Reyes C, Estella C. Role of the Forkhead Transcription Factors Fd4 and Fd5 During Drosophila Leg Development. Front Cell Dev Biol 2021; 9:723927. [PMID: 34409041 PMCID: PMC8365472 DOI: 10.3389/fcell.2021.723927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
Appendage development requires the coordinated function of signaling pathways and transcription factors to pattern the leg along the three main axes: the antero-posterior (AP), proximo-distal (PD), and dorso-ventral (DV). The Drosophila leg DV axis is organized by two morphogens, Decapentaplegic (Dpp), and Wingless (Wg), which direct dorsal and ventral cell fates, respectively. However, how these signals regulate the differential expression of its target genes is mostly unknown. In this work, we found that two members of the Drosophila forkhead family of transcription factors, Fd4 and Fd5 (also known as fd96Ca and fd96Cb), are identically expressed in the ventro-lateral domain of the leg imaginal disc in response to Dpp signaling. Here, we analyze the expression regulation and function of these genes during leg development. We have generated specific mutant alleles for each gene and a double fd4/fd5 mutant chromosome to study their function during development. We highlight the redundant role of the fd4/fd5 genes during the formation of the sex comb, a male specific structure that appears in the ventro-lateral domain of the prothoracic leg.
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Affiliation(s)
- Mireya Ruiz-Losada
- Centro de Biología Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristian Pérez-Reyes
- Centro de Biología Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, Madrid, Spain
| | - Carlos Estella
- Centro de Biología Molecular Severo Ochoa (C.S.I.C.-U.A.M.), Universidad Autónoma de Madrid, Madrid, Spain
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7
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Conserved Mechanisms, Novel Anatomies: The Developmental Basis of Fin Evolution and the Origin of Limbs. DIVERSITY 2021. [DOI: 10.3390/d13080384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The transformation of paired fins into tetrapod limbs is one of the most intensively scrutinized events in animal evolution. Early anatomical and embryological datasets identified distinctive morphological regions within the appendage and posed hypotheses about how the loss, gain, and transformation of these regions could explain the observed patterns of both extant and fossil appendage diversity. These hypotheses have been put to the test by our growing understanding of patterning mechanisms that regulate formation of the appendage axes, comparisons of gene expression data from an array of phylogenetically informative taxa, and increasingly sophisticated and elegant experiments leveraging the latest molecular approaches. Together, these data demonstrate the remarkable conservation of developmental mechanisms, even across phylogenetically and morphologically disparate taxa, as well as raising new questions about the way we view homology, evolutionary novelty, and the often non-linear connection between morphology and gene expression. In this review, we present historical hypotheses regarding paired fin evolution and limb origins, summarize key aspects of central appendage patterning mechanisms in model and non-model species, address how modern comparative developmental data interface with our understanding of appendage anatomy, and highlight new approaches that promise to provide new insight into these well-traveled questions.
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8
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McKenna KZ, Wagner GP, Cooper KL. A developmental perspective of homology and evolutionary novelty. Curr Top Dev Biol 2021; 141:1-38. [PMID: 33602485 DOI: 10.1016/bs.ctdb.2020.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The development and evolution of multicellular body plans is complex. Many distinct organs and body parts must be reproduced at each generation, and those that are traceable over long time scales are considered homologous. Among the most pressing and least understood phenomena in evolutionary biology is the mode by which new homologs, or "novelties" are introduced to the body plan and whether the developmental changes associated with such evolution deserve special treatment. In this chapter, we address the concepts of homology and evolutionary novelty through the lens of development. We present a series of case studies, within insects and vertebrates, from which we propose a developmental model of multicellular organ identity. With this model in hand, we make predictions regarding the developmental evolution of body plans and highlight the need for more integrative analysis of developing systems.
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Affiliation(s)
- Kenneth Z McKenna
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States
| | - Günter P Wagner
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States.
| | - Kimberly L Cooper
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States
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9
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Game M, Smith FW. Loss of intermediate regions of perpendicular body axes contributed to miniaturization of tardigrades. Proc Biol Sci 2020; 287:20201135. [PMID: 33043863 DOI: 10.1098/rspb.2020.1135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tardigrades have a miniaturized body plan. Miniaturization in tardigrades is associated with the loss of several organ systems and an intermediate region of their anteroposterior (AP) axis. However, how miniaturization has affected tardigrade legs is unclear. In arthropods and in onychophorans, the leg gap genes are expressed in regionalized proximodistal (PD) patterns in the legs. Functional studies indicate that these genes regulate growth in their respective expression domains and establish PD identities, partly through mutually antagonistic regulatory interactions. Here, we investigated the expression patterns of tardigrade orthologs of the leg gap genes. Rather than being restricted to a proximal leg region, as in arthropods and onychophorans, we detected coexpression of orthologues of homothorax and extradenticle broadly across the legs of the first three trunk segments in the tardigrade Hypsibius exemplaris. We could not identify a dachshund orthologue in tardigrade genomes, a gene that is expressed in an intermediate region of developing legs in arthropods and onychophorans, suggesting that this gene was lost in the tardigrade lineage. We detected Distal-less expression broadly across all developing leg buds in H. exemplaris embryos, unlike in arthropods and onychophorans, in which it exhibits a distally restricted expression domain. The broad expression patterns of the remaining leg gap genes in H. exemplaris legs may reflect the loss of dachshund and the accompanying loss of an intermediate region of the legs in the tardigrade lineage. We propose that the loss of intermediate regions of both the AP and PD body axes contributed to miniaturization of Tardigrada.
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Affiliation(s)
- Mandy Game
- Biology Department, University of North Florida, USA
| | - Frank W Smith
- Biology Department, University of North Florida, USA
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10
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Tarazona OA, Lopez DH, Slota LA, Cohn MJ. Evolution of limb development in cephalopod mollusks. eLife 2019; 8:43828. [PMID: 31210127 PMCID: PMC6581508 DOI: 10.7554/elife.43828] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 05/08/2019] [Indexed: 11/13/2022] Open
Abstract
Cephalopod mollusks evolved numerous anatomical novelties, including arms and tentacles, but little is known about the developmental mechanisms underlying cephalopod limb evolution. Here we show that all three axes of cuttlefish limbs are patterned by the same signaling networks that act in vertebrates and arthropods, although they evolved limbs independently. In cuttlefish limb buds, Hedgehog is expressed anteriorly. Posterior transplantation of Hedgehog-expressing cells induced mirror-image limb duplications. Bmp and Wnt signals, which establish dorsoventral polarity in vertebrate and arthropod limbs, are similarly polarized in cuttlefish. Inhibition of Bmp2/4 dorsally caused ectopic expression of Notum, which marks the ventral sucker field, and ectopic sucker development. Cuttlefish also show proximodistal regionalization of Hth, Exd, Dll, Dac, Sp8/9, and Wnt expression, which delineates arm and tentacle sucker fields. These results suggest that cephalopod limbs evolved by parallel activation of a genetic program for appendage development that was present in the bilaterian common ancestor.
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Affiliation(s)
- Oscar A Tarazona
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, United States.,Department of Biology, UF Genetics Institute, University of Florida, Gainesville, United States
| | - Davys H Lopez
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, United States
| | - Leslie A Slota
- Department of Biology, UF Genetics Institute, University of Florida, Gainesville, United States
| | - Martin J Cohn
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, United States.,Department of Biology, UF Genetics Institute, University of Florida, Gainesville, United States
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11
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Abstract
The same genes and signaling pathways control the formation of limbs in vertebrates, arthropods and cuttlefish.
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Affiliation(s)
- Nikola-Michael Prpic
- Allgemeine Zoologie und Entwicklungsbiologie, Justus-Liebig-Universität Gießen, Gießen, Germany
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12
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Mier P, Andrade-Navarro MA. Traitpedia: a collaborative effort to gather species traits. Bioinformatics 2019; 35:1079-1081. [PMID: 30165582 PMCID: PMC6419907 DOI: 10.1093/bioinformatics/bty743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 08/17/2018] [Accepted: 08/23/2018] [Indexed: 11/25/2022] Open
Abstract
Summary Traitpedia is a collaborative database aimed to collect binary traits in a tabular form for a growing number of species. Availability and implementation Traitpedia can be accessed from http://cbdm-01.zdv.uni-mainz.de/~munoz/traitpedia. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Pablo Mier
- Faculty of Biology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
| | - Miguel A Andrade-Navarro
- Faculty of Biology, Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
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13
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Ruiz-Losada M, Blom-Dahl D, Córdoba S, Estella C. Specification and Patterning of Drosophila Appendages. J Dev Biol 2018; 6:jdb6030017. [PMID: 30011921 PMCID: PMC6162442 DOI: 10.3390/jdb6030017] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 07/10/2018] [Accepted: 07/12/2018] [Indexed: 02/06/2023] Open
Abstract
Appendages are external projections of the body that serve the animal for locomotion, feeding, or environment exploration. The appendages of the fruit fly Drosophilamelanogaster are derived from the imaginal discs, epithelial sac-like structures specified in the embryo that grow and pattern during larva development. In the last decades, genetic and developmental studies in the fruit fly have provided extensive knowledge regarding the mechanisms that direct the formation of the appendages. Importantly, many of the signaling pathways and patterning genes identified and characterized in Drosophila have similar functions during vertebrate appendage development. In this review, we will summarize the genetic and molecular mechanisms that lead to the specification of appendage primordia in the embryo and their posterior patterning during imaginal disc development. The identification of the regulatory logic underlying appendage specification in Drosophila suggests that the evolutionary origin of the insect wing is, in part, related to the development of ventral appendages.
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Affiliation(s)
- Mireya Ruiz-Losada
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM/CSIC), Nicolás Cabrera 1, 28049 Madrid, Spain.
| | - David Blom-Dahl
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM/CSIC), Nicolás Cabrera 1, 28049 Madrid, Spain.
| | - Sergio Córdoba
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM/CSIC), Nicolás Cabrera 1, 28049 Madrid, Spain.
| | - Carlos Estella
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM/CSIC), Nicolás Cabrera 1, 28049 Madrid, Spain.
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14
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Erwin DH. Eric Davidson and deep time. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2017; 39:29. [PMID: 29030723 DOI: 10.1007/s40656-017-0156-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Eric Davidson had a deep and abiding interest in the role developmental mechanisms played in generating evolutionary patterns documented in deep time, from the origin of the euechinoids to the processes responsible for the morphological architectures of major animal clades. Although not an evolutionary biologist, Davidson's interests long preceded the current excitement over comparative evolutionary developmental biology. Here I discuss three aspects at the intersection between his research and evolutionary patterns in deep time: First, understanding the mechanisms of body plan formation, particularly those associated with the early diversification of major metazoan clades. Second, a critique of early claims about ancestral metazoans based on the discoveries of highly conserved genes across bilaterian animals. Third, Davidson's own involvement in paleontology through a collaborative study of the fossil embryos from the Ediacaran Doushantuo Formation in south China.
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Affiliation(s)
- Douglas H Erwin
- Department of Paleobiology, MRC-121, National Museum of Natural History, Washington, DC, 20013-7012, USA.
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15
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Pflugfelder G, Eichinger F, Shen J. T-Box Genes in Drosophila Limb Development. Curr Top Dev Biol 2017; 122:313-354. [DOI: 10.1016/bs.ctdb.2016.08.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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16
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Grimmel J, Dorresteijn AWC, Fröbius AC. Formation of body appendages during caudal regeneration in Platynereis dumerilii: adaptation of conserved molecular toolsets. EvoDevo 2016; 7:10. [PMID: 27076904 PMCID: PMC4830062 DOI: 10.1186/s13227-016-0046-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 03/30/2016] [Indexed: 01/13/2023] Open
Abstract
Background Platynereis and other polychaete annelids with homonomous segmentation are regarded to closely resemble ancestral forms of bilateria. The head region comprises the prostomium, the peristomium, a variable number of cephalized body segments and several appendages, like cirri, antennae and palps. The trunk of such polychaetes shows numerous, nearly identical segments. Each segment bears a parapodium with species-specific morphology on either side. The posterior end of the trunk features a segment proliferation zone and a terminal pygidium with the anus and anal cirri. The removal of a substantial part of the posterior trunk is by no means lethal. Cells at the site of injury dedifferentiate and proliferate forming a blastema to regenerate both the pygidium and the proliferation zone. The pygidium forms new anal cirri, and the proliferation zone generates new segments at a rapid pace. The formation of body appendages like the cirri and the segmental parapodia can thus be studied in the caudal regenerate of Platynereis within only a few days. Results The development of body appendages in Platynereis is regulated by a network of genes common to polychaetes but also shared by distant taxa. We isolated DNA sequences from P. dumerilii of five genes known to be involved in appendage formation within other groups: Meis/homothorax, Pbx1/extradenticle, Dlx/Distal-less, decapentaplegic and specificprotein1/buttonhead. Analyses of expression patterns during caudal regeneration by in situ hybridization reveal striking similarities related to expression in arthropods and vertebrates. All genes exhibit transient expression during differentiation and growth of segments. As was shown previously in other phyla Pdu-Meis/hth and Pdu-Pbx1/exd are co-expressed, although the expression is not limited to the proximal part of the parapodia. Pdu-Dll is prominent in parapodia but upregulated in the anal cirri. No direct dependence concerning Pdu-Dll and Pdu-sp/btd expression is observed in Platynereis. Pdu-dpp shows an expression pattern not comparable to its expression in other taxa. Conclusions The expression patterns observed suggest conserved roles of these genes during appendage formation across different clades, but the underlying mechanisms utilizing this toolset might not be identical. Some genes show broad expression along the proximodistal axis indicating a possible role in proximodistal patterning of body appendages. Other genes exhibit expression patterns limited to specific parts and tissues of the growing parapodia, thus presumably being involved in formation of taxon-specific morphological differences. Electronic supplementary material The online version of this article (doi:10.1186/s13227-016-0046-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jan Grimmel
- Institut für Allgemeine und Spezielle Zoologie, Abteilung Entwicklungsbiologie, Justus-Liebig-Universität Gießen, Stephanstraße 24, 35390 Gießen, Germany
| | - Adriaan W C Dorresteijn
- Institut für Allgemeine und Spezielle Zoologie, Abteilung Entwicklungsbiologie, Justus-Liebig-Universität Gießen, Stephanstraße 24, 35390 Gießen, Germany
| | - Andreas C Fröbius
- Institut für Allgemeine und Spezielle Zoologie, Abteilung Entwicklungsbiologie, Justus-Liebig-Universität Gießen, Stephanstraße 24, 35390 Gießen, Germany
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17
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Grubbs N, Leach M, Su X, Petrisko T, Rosario JB, Mahaffey JW. New components of Drosophila leg development identified through genome wide association studies. PLoS One 2013; 8:e60261. [PMID: 23560084 PMCID: PMC3613359 DOI: 10.1371/journal.pone.0060261] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 02/24/2013] [Indexed: 11/29/2022] Open
Abstract
The adult Drosophila melanogaster body develops from imaginal discs, groups of cells set-aside during embryogenesis and expanded in number during larval stages. Specification and development of Drosophila imaginal discs have been studied for many years as models of morphogenesis. These studies are often based on mutations with large developmental effects, mutations that are often lethal in embryos when homozygous. Such forward genetic screens can be limited by factors such as early lethality and genetic redundancy. To identify additional genes and genetic pathways involved in leg imaginal disc development, we employed a Genome Wide Association Study utilizing the natural genetic variation in leg proportionality found in the Drosophila Genetic Reference Panel fly lines. In addition to identifying genes already known to be involved in leg development, we identified several genes involved in pathways that had not previously been linked with leg development. Several of the genes appear to be involved in signaling activities, while others have no known roles at this time. Many of these uncharacterized genes are conserved in mammals, so we can now begin to place these genes into developmental contexts. Interestingly, we identified five genes which, when their function is reduced by RNAi, cause an antenna-to-leg transformation. Our results demonstrate the utility of this approach, integrating the tools of quantitative and molecular genetics to study developmental processes, and provide new insights into the pathways and networks involved in Drosophila leg development.
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Affiliation(s)
- Nathaniel Grubbs
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Megan Leach
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Xin Su
- Transgenics Department, Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | | | - Juan B. Rosario
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
| | - James W. Mahaffey
- Department of Genetics, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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18
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Winchell CJ, Jacobs DK. Expression of the Lhx genes apterous and lim1 in an errant polychaete: implications for bilaterian appendage evolution, neural development, and muscle diversification. EvoDevo 2013; 4:4. [PMID: 23369627 PMCID: PMC3579752 DOI: 10.1186/2041-9139-4-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 12/03/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Arthropod and vertebrate appendages appear to have evolved via parallel co-option of a plesiomorphic gene regulatory network. Our previous work implies that annelids evolved unrelated appendage-forming mechanisms; we therefore found no support for homology of parapodia and arthropodia at the level of the whole appendage. We expand on that study here by asking whether expression of the LIM homeobox (Lhx) genes apterous and lim1 in the annelid Neanthes arenaceodentata supports homology of the dorsal branches as well as the proximodistal axes of parapodia and arthropodia. In addition, we explore whether the neural expression of apterous and lim1 in Neanthes supports the putative ancestral function of the Lhx gene family in regulating the differentiation and maintenance of neuronal subtypes. RESULTS Both genes exhibit continuous expression in specific portions of the developing central nervous system, from hatching to at least the 13-chaetiger stage. For example, nerve cord expression occurs in segmentally iterated patterns consisting of diffuse sets of many lim1-positive cells and comparatively fewer, clustered pairs of apterous-positive cells. Additionally, continuous apterous expression is observed in presumed neurosecretory ganglia of the posterior brain, while lim1 is continuously expressed in stomatogastric ganglia of the anterior brain. apterous is also expressed in the jaw sacs, dorsal parapodial muscles, and a presumed pair of cephalic sensory organs, whereas lim1 is expressed in multiple pharyngeal ganglia, the segmental peripheral nervous system, neuropodial chaetal sac muscles, and parapodial ligules. CONCLUSIONS The early and persistent nervous system expression of apterous and lim1 in Neanthes juveniles supports conservation of Lhx function in bilaterian neural differentiation and maintenance. Our results also suggest that diversification of parapodial muscle precursors involves a complementary LIM code similar to those generating distinct neuronal identities in fly and mouse nerve cords. Expression of apterous and lim1 in discrete components of developing parapodia is intriguing but does not map to comparable expression of these genes in developing arthropod appendages. Thus, annelid and arthropod appendage development apparently evolved, in part, via distinct co-option of the neuronal regulatory architecture. These divergent patterns of apterous and lim1 activity seemingly reflect de novo origins of parapodia and arthropodia, although we discuss alternative hypotheses.
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Affiliation(s)
- Christopher J Winchell
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E Young Drive South, Los Angeles, CA 90095-1606, USA
- Present address: Department of Molecular and Cell Biology, University of California, Berkeley, 515 LSA #3200, Berkeley, CA 94720-3200, USA
| | - David K Jacobs
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E Young Drive South, Los Angeles, CA 90095-1606, USA
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19
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Mitten EK, Jing D, Suzuki Y. Matrix metalloproteinases (MMPs) are required for wound closure and healing during larval leg regeneration in the flour beetle, Tribolium castaneum. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 42:854-864. [PMID: 22940602 DOI: 10.1016/j.ibmb.2012.08.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 08/04/2012] [Accepted: 08/13/2012] [Indexed: 06/01/2023]
Abstract
Regenerative abilities are found ubiquitously among many metazoan taxa. To compare mechanisms underlying the initial stages of limb regeneration between insects and vertebrates, the roles of matrix metalloproteinases (MMPs) and fibroblast growth factor (FGF) signaling were investigated in the red flour beetle, Tribolium castaneum. RNA interference-mediated knockdown of MMP2 expression delayed wound healing and subsequent leg regeneration. Additionally, pairwise knockdown of MMP1/2 and MMP2/3, but not MMP1/3, resulted in inhibition of wound closure. Wound healing on the dorsal epidermis after injury was also delayed when MMPs were silenced. Our findings show that functionally redundant MMPs play key roles during limb regeneration and wound healing in Tribolium. This MMP-mediated wound healing is necessary for the subsequent formation of a blastema. In contrast, silencing of FGF receptor did not interfere with the initial stages of leg regeneration despite the alterations in tanning of the cuticle. Thus, insects and vertebrates appear to employ similar developmental processes for the initial stages of wound closure during limb regeneration, while the role of FGF in limb regeneration appears to be unique to vertebrates.
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Affiliation(s)
- Emilie K Mitten
- Department of Biological Sciences, Wellesley College, 106 Central St., Wellesley, MA 02481, USA
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20
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Mabee BP, Balhoff JP, Dahdul WM, Lapp H, Midford PE, Vision TJ, Westerfield M. 500,000 fish phenotypes: The new informatics landscape for evolutionary and developmental biology of the vertebrate skeleton. ZEITSCHRIFT FUR ANGEWANDTE ICHTHYOLOGIE = JOURNAL OF APPLIED ICHTHYOLOGY 2012; 28:300-305. [PMID: 22736877 PMCID: PMC3377363 DOI: 10.1111/j.1439-0426.2012.01985.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 03/08/2012] [Indexed: 05/02/2023]
Abstract
The rich phenotypic diversity that characterizes the vertebrate skeleton results from evolutionary changes in regulation of genes that drive development. Although relatively little is known about the genes that underlie the skeletal variation among fish species, significant knowledge of genetics and development is available for zebrafish. Because developmental processes are highly conserved, this knowledge can be leveraged for understanding the evolution of skeletal diversity. We developed the Phenoscape Knowledgebase (KB; http://kb.phenoscape.org) to yield testable hypotheses of candidate genes involved in skeletal evolution. We developed a community anatomy ontology for fishes and ontology-based methods to represent complex free-text character descriptions of species in a computable format. With these tools, we populated the KB with comparative morphological data from the literature on over 2,500 teleost fishes (mainly Ostariophysi) resulting in over 500,000 taxon phenotype annotations. The KB integrates these data with similarly structured phenotype data from zebrafish genes (http://zfin.org). Using ontology-based reasoning, candidate genes can be inferred for the phenotypes that vary across taxa, thereby uniting genetic and phenotypic data to formulate evo-devo hypotheses. The morphological data in the KB can be browsed, sorted, and aggregated in ways that provide unprecedented possibilities for data mining and discovery.
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Affiliation(s)
- By Paula Mabee
- Department of Biology, 414 East Clark Street, University of South Dakota, Vermillion, South Dakota, United States of America
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21
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Bertossa RC. Morphology and behaviour: functional links in development and evolution. Philos Trans R Soc Lond B Biol Sci 2011; 366:2056-68. [PMID: 21690124 PMCID: PMC3130372 DOI: 10.1098/rstb.2011.0035] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Development and evolution of animal behaviour and morphology are frequently addressed independently, as reflected in the dichotomy of disciplines dedicated to their study distinguishing object of study (morphology versus behaviour) and perspective (ultimate versus proximate). Although traits are known to develop and evolve semi-independently, they are matched together in development and evolution to produce a unique functional phenotype. Here I highlight similarities shared by both traits, such as the decisive role played by the environment for their ontogeny. Considering the widespread developmental and functional entanglement between both traits, many cases of adaptive evolution are better understood when proximate and ultimate explanations are integrated. A field integrating these perspectives is evolutionary developmental biology (evo-devo), which studies the developmental basis of phenotypic diversity. Ultimate aspects in evo-devo studies--which have mostly focused on morphological traits--could become more apparent when behaviour, 'the integrator of form and function', is integrated into the same framework of analysis. Integrating a trait such as behaviour at a different level in the biological hierarchy will help to better understand not only how behavioural diversity is produced, but also how levels are connected to produce functional phenotypes and how these evolve. A possible framework to accommodate and compare form and function at different levels of the biological hierarchy is outlined. At the end, some methodological issues are discussed.
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Affiliation(s)
- Rinaldo C Bertossa
- Centre for Behaviour and Neurosciences & Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 11103, 9700 Groningen, The Netherlands.
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22
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Turchyn N, Chesebro J, Hrycaj S, Couso JP, Popadić A. Evolution of nubbin function in hemimetabolous and holometabolous insect appendages. Dev Biol 2011; 357:83-95. [PMID: 21708143 DOI: 10.1016/j.ydbio.2011.06.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 06/10/2011] [Accepted: 06/11/2011] [Indexed: 10/18/2022]
Abstract
Insects display a whole spectrum of morphological diversity, which is especially noticeable in the organization of their appendages. A recent study in a hemipteran, Oncopeltus fasciatus (milkweed bug), showed that nubbin (nub) affects antenna morphogenesis, labial patterning, the length of the femoral segment in legs, and the formation of a limbless abdomen. To further determine the role of this gene in the evolution of insect morphology, we analyzed its functions in two additional hemimetabolous species, Acheta domesticus (house cricket) and Periplaneta americana (cockroach), and re-examined its role in Drosophila melanogaster (fruit fly). While both Acheta and Periplaneta nub-RNAi first nymphs develop crooked antennae, no visible changes are observed in the morphologies of their mouthparts and abdomen. Instead, the main effect is seen in legs. The joint between the tibia and first tarsomere (Ta-1) is lost in Acheta, which in turn, causes a fusion of these two segments and creates a chimeric nub-RNAi tibia-tarsus that retains a tibial identity in its proximal half and acquires a Ta-1 identity in its distal half. Similarly, our re-analysis of nub function in Drosophila reveals that legs lack all true joints and the fly tibia also exhibits a fused tibia and tarsus. Finally, we observe a similar phenotype in Periplaneta except that it encompasses different joints (coxa-trochanter and femur-tibia), and in this species we also show that nub expression in the legs is regulated by Notch signaling, as had previously been reported in flies and spiders. Overall, we propose that nub acts downstream of Notch on the distal part of insect leg segments to promote their development and growth, which in turn is required for joint formation. Our data represent the first functional evidence defining a role for nub in leg segmentation and highlight the varying degrees of its involvement in this process across insects.
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Affiliation(s)
- Nataliya Turchyn
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
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23
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Capellini TD, Zappavigna V, Selleri L. Pbx homeodomain proteins: TALEnted regulators of limb patterning and outgrowth. Dev Dyn 2011; 240:1063-86. [PMID: 21416555 DOI: 10.1002/dvdy.22605] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2011] [Indexed: 12/14/2022] Open
Abstract
Limb development has long provided an excellent model for understanding the genetic principles driving embryogenesis. Studies utilizing chick and mouse have led to new insights into limb patterning and morphogenesis. Recent research has centered on the regulatory networks underlying limb development. Here, we discuss the hierarchical, overlapping, and iterative roles of Pbx family members in appendicular development that have emerged from genetic analyses in the mouse. Pbx genes are essential in determining limb bud positioning, early bud formation, limb axes establishment and coordination, and patterning and morphogenesis of most elements of the limb and girdle. Pbx proteins directly regulate critical effectors of limb and girdle development, including morphogen-encoding genes like Shh in limb posterior mesoderm, and transcription factor-encoding genes like Alx1 in pre-scapular domains. Interestingly, at least in limb buds, Pbx appear to act not only as Hox cofactors, but also in the upstream control of 5' HoxA/D gene expression.
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Affiliation(s)
- Terence D Capellini
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, New York, USA
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24
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Control of Distal-less expression in the Drosophila appendages by functional 3' enhancers. Dev Biol 2011; 353:396-410. [PMID: 21320482 DOI: 10.1016/j.ydbio.2011.02.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Revised: 02/04/2011] [Accepted: 02/06/2011] [Indexed: 11/22/2022]
Abstract
The expression of the Hox gene Distal-less (Dll) directs the development of appendages in a wide variety of animals. In Drosophila, its expression is subjected to a complex developmental control. In the present work we have studied a 17kb genomic region in the Dll locus which lies downstream of the coding sequence and found control elements of primary functional importance for the expression of Dll in the leg and in other tissues. Of particular interest is a control element, which we have called LP, which drives expression of Dll in the leg primordium from early embryonic development, and whose deletion causes severe truncation and malformation of the adult leg. This is the first Dll enhancer for which, in addition to the ability to drive expression of a reporter, a role can be demonstrated in the expression of the endogenous Dll gene and in the development of the leg. In addition, our results suggest that some enhancers, contrary to the widely accepted notion, may require a specific 5' or 3' position with respect to the transcribed region.
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25
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Winchell CJ, Valencia JE, Jacobs DK. Expression of Distal-less, dachshund, and optomotor blind in Neanthes arenaceodentata (Annelida, Nereididae) does not support homology of appendage-forming mechanisms across the Bilateria. Dev Genes Evol 2010; 220:275-95. [PMID: 21116826 PMCID: PMC3005117 DOI: 10.1007/s00427-010-0346-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 11/09/2010] [Indexed: 01/11/2023]
Abstract
The similarity in the genetic regulation of arthropod and vertebrate appendage formation has been interpreted as the product of a plesiomorphic gene network that was primitively involved in bilaterian appendage development and co-opted to build appendages (in modern phyla) that are not historically related as structures. Data from lophotrochozoans are needed to clarify the pervasiveness of plesiomorphic appendage-forming mechanisms. We assayed the expression of three arthropod and vertebrate limb gene orthologs, Distal-less (Dll), dachshund (dac), and optomotor blind (omb), in direct-developing juveniles of the polychaete Neanthes arenaceodentata. Parapodial Dll expression marks pre-morphogenetic notopodia and neuropodia, becoming restricted to the bases of notopodial cirri and to ventral portions of neuropodia. In outgrowing cephalic appendages, Dll activity is primarily restricted to proximal domains. Dll expression is also prominent in the brain. dac expression occurs in the brain, nerve cord ganglia, a pair of pharyngeal ganglia, presumed interneurons linking a pair of segmental nerves, and in newly differentiating mesoderm. Domains of omb expression include the brain, nerve cord ganglia, one pair of anterior cirri, presumed precursors of dorsal musculature, and the same pharyngeal ganglia and presumed interneurons that express dac. Contrary to their roles in outgrowing arthropod and vertebrate appendages, Dll, dac, and omb lack comparable expression in Neanthes appendages, implying independent evolution of annelid appendage development. We infer that parapodia and arthropodia are not structurally or mechanistically homologous (but their primordia might be), that Dll's ancestral bilaterian function was in sensory and central nervous system differentiation, and that locomotory appendages possibly evolved from sensory outgrowths.
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Affiliation(s)
- Christopher J. Winchell
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606 USA
| | - Jonathan E. Valencia
- Division of Biology, California Institute of Technology, 1200 East California Boulevard; MC 156-29, Pasadena, CA 91125 USA
| | - David K. Jacobs
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606 USA
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26
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Cui ML, Copsey L, Green AA, Bangham JA, Coen E. Quantitative control of organ shape by combinatorial gene activity. PLoS Biol 2010; 8:e1000538. [PMID: 21085695 PMCID: PMC2976723 DOI: 10.1371/journal.pbio.1000538] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 09/28/2010] [Indexed: 01/21/2023] Open
Abstract
A novel combination of molecular genetics, shape analysis, and computational modelling shows how the complex three-dimensional shape of the Snapdragon flower can arise through local gene activity. The development of organs with particular shapes, like wings or flowers, depends on regional activity of transcription factors and signalling molecules. However, the mechanisms that link these molecular activities to the morphogenetic events underlying shape are poorly understood. Here we describe a combination of experimental and computational approaches that address this problem, applying them to a group of genes controlling flower shape in the Snapdragon (Antirrhinum). Four transcription factors are known to play a key role in the control of floral shape and asymmetry in Snapdragon. We use quantitative shape analysis of mutants for these factors to define principal components underlying flower shape variation. We show that each transcription factor has a specific effect on the shape and size of regions within the flower, shifting the position of the flower in shape space. These shifts are further analysed by generating double mutants and lines that express some of the genes ectopically. By integrating these observations with known gene expression patterns and interactions, we arrive at a combinatorial scheme for how regional effects on shape are genetically controlled. We evaluate our scheme by incorporating the proposed interactions into a generative model, where the developing flower is treated as a material sheet that grows according to how genes modify local polarities and growth rates. The petal shapes generated by the model show a good quantitative match with those observed experimentally for each petal in numerous genotypes, thus validating the hypothesised scheme. This article therefore shows how complex shapes can be accounted for by combinatorial effects of transcription factors on regional growth properties. This finding has implications not only for how shapes develop but also for how they may have evolved through tinkering with transcription factors and their targets. A major challenge in developmental biology is to understand how patterns of gene activity are translated into complex three-dimensional forms, like hearts, wings, or flowers. Addressing this problem has not been easy, partly because of the difficulties in quantifying the effects of genes on shape and also because we lack frameworks that allow hypotheses about underlying mechanisms to be evaluated. Here we address this issue through a combination of experimental and computational approaches, using the Snapdragon flower as a model system. By quantifying the shapes of these flowers in a range of mutants with reduced or increased activity of particular genes, we show how the complex floral shape depends on the way genes act in combination in each petal region. The proposed interactions were tested by incorporating them into a computational model of the growing flower. Quantitative comparisons reveal a good agreement between the shapes generated by the model and those observed experimentally, confirming our underlying hypothesis. The Snapdragon flower, with its tightly fitting upper and lower petals, has evolved as a specialised mechanism for targeting pollinators. Our article shows how the development and evolution of such forms may have arisen by natural tinkering with the local effects of genes on growth.
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Affiliation(s)
- Min-Long Cui
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Lucy Copsey
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Amelia A. Green
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - J. Andrew Bangham
- University of East Anglia, School of Computing Sciences, Norwich, United Kingdom
| | - Enrico Coen
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
- * E-mail:
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27
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Singh BN, Koyano-Nakagawa N, Garry JP, Weaver CV. Heart of newt: a recipe for regeneration. J Cardiovasc Transl Res 2010; 3:397-409. [PMID: 20559775 DOI: 10.1007/s12265-010-9191-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 04/22/2010] [Indexed: 01/17/2023]
Abstract
The field of regenerative medicine holds tremendous promise for the treatment of chronic diseases. While the adult mammalian heart has limited regenerative capacity, previous studies have focused on cellular therapeutic strategies in an attempt to modulate cardiac regeneration. An alternative strategy relies on the modulation of endogenous stem/progenitor cells or signaling pathways to promote cardiac regeneration. Several organisms, including the newt, have an incomparable capacity for the regeneration of differentiated tissues. An enhanced understanding of the signals, pathways, and factors that mediate the regenerative response in these organisms may be useful in modulating the regenerative response of mammalian organs including the injured adult heart.
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Affiliation(s)
- Bhairab N Singh
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA
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28
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Lemons D, Fritzenwanker JH, Gerhart J, Lowe CJ, McGinnis W. Co-option of an anteroposterior head axis patterning system for proximodistal patterning of appendages in early bilaterian evolution. Dev Biol 2010; 344:358-62. [PMID: 20435033 DOI: 10.1016/j.ydbio.2010.04.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 04/22/2010] [Indexed: 10/19/2022]
Abstract
The enormous diversity of extant animal forms is a testament to the power of evolution, and much of this diversity has been achieved through the emergence of novel morphological traits. The origin of novel morphological traits is an extremely important issue in biology, and a frequent source of this novelty is co-option of pre-existing genetic systems for new purposes (Carroll et al., 2008). Appendages, such as limbs, fins and antennae, are structures common to many animal body plans which must have arisen at least once, and probably multiple times, in lineages which lacked appendages. We provide evidence that appendage proximodistal patterning genes are expressed in similar registers in the anterior embryonic neurectoderm of Drosophila melanogaster and Saccoglossus kowalevskii (a hemichordate). These results, in concert with existing expression data from a variety of other animals suggest that a pre-existing genetic system for anteroposterior head patterning was co-opted for patterning of the proximodistal axis of appendages of bilaterian animals.
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Affiliation(s)
- Derek Lemons
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0349, USA
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29
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Mariani FV. Proximal to distal patterning during limb development and regeneration: a review of converging disciplines. Regen Med 2010; 5:451-62. [DOI: 10.2217/rme.10.27] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Regeneration of lost structures typically involves distinct events: wound healing at the damaged site, the accumulation of cells that will be used as future building blocks and, finally, the initiation of molecular signaling pathways that dictate the form and pattern of the regenerated structures. Amphibians and urodeles in particular, have long been known to have exceptional regenerative properties. For many years, these animals have been the model of choice for understanding limb regeneration, a complex process that involves reconstructing skin, muscle, bone, connective tissue and nerves into a functional 3D structure. It appears that this process of rebuilding an adult limb has many similarities with how the limb forms in the first place – for example, in the embryo, all the components of the limb need to be formed and this requires signaling mechanisms to specify the final pattern. Thus, both limb formation and limb regeneration are likely to employ the same molecular pathways. Given the available tools of molecular biology and genetics, this is an exciting time for both fields to share findings and make significant progress in understanding more about the events that dictate embryonic limb pattern and control limb regeneration. This article focuses particularly on what is known about the molecular control of patterning along the proximal–distal axis.
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Affiliation(s)
- Francesca V Mariani
- Eli & Edythe Broad Center for Regenerative Medicine & Stem Cell Research, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT-4505, Los Angeles, CA 90033-9601, USA
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30
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Tal TL, Franzosa JA, Tanguay RL. Molecular signaling networks that choreograph epimorphic fin regeneration in zebrafish - a mini-review. Gerontology 2009; 56:231-40. [PMID: 19923791 DOI: 10.1159/000259327] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 07/28/2009] [Indexed: 12/11/2022] Open
Abstract
This short review provides a current synopsis of caudal fin regeneration in zebrafish with an emphasis on the molecular signaling networks that dictate epimorphic regeneration. At the outset, the fundamentals of caudal fin architecture and the stages of epimorphic regeneration are described. This is followed by a detailed look at the main networks implicated in fin regeneration, namely the Wnt, fibroblast growth factor, activin-betaA, retinoic acid and hedgehog signaling pathways. Throughout this mini-review, these molecular networks are examined through the lens of wound healing, blastema formation or regenerative outgrowth, three of the main stages of epimorphic regeneration. Next, the emerging role of noncoding RNAs as regulators of regeneration and mechanisms of regenerative termination are discussed. Finally, the implications for future research and the broader field of regenerative medicine are examined.
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Affiliation(s)
- Tamara L Tal
- Department of Environmental and Molecular Toxicology, Environmental Health Sciences Center, Oregon State University, Corvallis, 97331-7301, USA
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31
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Erwin DH. Early origin of the bilaterian developmental toolkit. Philos Trans R Soc Lond B Biol Sci 2009; 364:2253-61. [PMID: 19571245 DOI: 10.1098/rstb.2009.0038] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Whole-genome sequences from the choanoflagellate Monosiga brevicollis, the placozoan Trichoplax adhaerens and the cnidarian Nematostella vectensis have confirmed results from comparative evolutionary developmental studies that much of the developmental toolkit once thought to be characteristic of bilaterians appeared much earlier in the evolution of animals. The diversity of transcription factors and signalling pathway genes in animals with a limited number of cell types and a restricted developmental repertoire is puzzling, particularly in light of claims that such highly conserved elements among bilaterians provide evidence of a morphologically complex protostome-deuterostome ancestor. Here, I explore the early origination of elements of what became the bilaterian toolkit, and suggest that placozoans and cnidarians represent a depauperate residue of a once more diverse assemblage of early animals, some of which may be represented in the Ediacaran fauna (c. 585-542 Myr ago).
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Affiliation(s)
- Douglas H Erwin
- Department of Paleobiology, MRC-121, National Museum of Natural History, Washington, DC 20013-7012, USA.
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Prpic NM, Damen WGM. Notch-mediated segmentation of the appendages is a molecular phylotypic trait of the arthropods. Dev Biol 2008; 326:262-71. [PMID: 19046962 DOI: 10.1016/j.ydbio.2008.10.049] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/28/2008] [Accepted: 10/31/2008] [Indexed: 11/16/2022]
Abstract
Arthropod limbs are arguably the most diverse organs in the animal kingdom. Morphological diversity of the limbs is largely based on their segmentation, because this divides the limbs into modules that can evolve separately for new morphologies and functions. Limb segmentation also distinguishes the arthropods from related phyla (e.g. onychophorans) and thus forms an important evolutionary innovation in arthropods. Understanding the genetic basis of limb segmentation in arthropods can thus shed light onto the mechanisms of macroevolution and the origin of a character (articulated limbs) that defines a new phylum (arthropods). In the fly Drosophila limb segmentation and limb growth are controlled by the Notch signaling pathway. Here we show that the Notch pathway also controls limb segmentation and growth in the spider Cupiennius salei, a representative of the most basally branching arthropod group Chelicerata, and thus this function must trace from the last common ancestor of all arthropods. The similarities of Notch and Serrate function between Drosophila and Cupiennius are extensive and also extend to target genes like odd-skipped, nubbin, AP-2 and hairy related genes. Our data confirm that the jointed appendages, which are a morphological phylotypic trait of the arthropods and the basis for naming the phylum, have a common developmental genetic basis. Notch-mediated limb segmentation is thus a molecular phylotypic trait of the arthropods.
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Affiliation(s)
- Nikola-Michael Prpic
- Institut für Genetik, Universität zu Köln, Zülpicher Str. 47, 50674 Köln, Germany
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The Drosophila gene zfh2 is required to establish proximal-distal domains in the wing disc. Dev Biol 2008; 320:102-12. [PMID: 18571155 DOI: 10.1016/j.ydbio.2008.04.028] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 04/08/2008] [Accepted: 04/24/2008] [Indexed: 01/05/2023]
Abstract
Three main events characterize the development of the proximal-distal axis of the Drosophila wing disc: first, generation of nested circular domains defined by different combinations of gene expression; second, activation of wingless (wg) gene expression in a ring of cells; and third, an increase of cell number in each domain in response to Wg. The mechanisms by which these domains of gene expression are established and maintained are unknown. We have analyzed the role of the gene zinc finger homeodomain 2 (zfh2). We report that in discs lacking zfh2 the limits of the expression domains of the genes tsh, nub, rn, dve and nab coincide, and expression of wg in the wing hinge, is lost. We show that zfh2 expression is delimited distally by Vg, Nub and Dpp signalling, and proximally by Tsh and Dpp. Distal repression of zfh2 permits activation of nab in the wing blade and wg in the wing hinge. We suggest that the proximal-most wing fate, the hinge, is specified first and that later repression of zfh2 permits specification of the distal-most fate, the wing blade. We propose that proximal-distal axis development is achieved by a combination of two strategies: on one hand a process involving proximal to distal specification, with the wing hinge specified first followed later by the distal wing blade; on the other hand, early specification of the proximal-distal domains by different combinations of gene expression. The results we present here indicate that Zfh2 plays a critical role in both processes.
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Abstract
Regulation of size is one of the fundamental problems in biology. One general strategy has been to identify molecules required for cell growth and cell proliferation within an organ. This has been particularly revealing, identifying cell-autonomous pathways involved in cell growth, survival and proliferation. In order to identify pathways regulating overall limb growth and morphology, experiments have evaluated gene expression, transplanted and removed tissues, and knocked out genes. This work has provided a vast amount of information identifying molecular mechanisms regulating limb axis formation, outgrowth, and pattern formation. Using the zebrafish fin, genetic, cellular and molecular strategies have also been employed to follow both normal patterns of fin growth and growth in fin mutants. This review will focus on cellular and molecular regulation of the outgrowth and patterning of the zebrafish caudal fin during regeneration, and will emphasize similarities to other systems. Future perspectives describe opportunities using the zebrafish fin to reveal mechanisms underlying the regulation of final size.
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Affiliation(s)
- M Kathryn Iovine
- Lehigh University Department of Biological Sciences, 111 Research Drive, Iacocca B217, Bethlehem, Pennsylvania 18015, USA.
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