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Gainett G, Klementz BC, Blaszczyk P, Setton EVW, Murayama GP, Willemart R, Gavish-Regev E, Sharma PP. Vestigial organs alter fossil placements in an ancient group of terrestrial chelicerates. Curr Biol 2024; 34:1258-1270.e5. [PMID: 38401545 DOI: 10.1016/j.cub.2024.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/01/2023] [Accepted: 02/06/2024] [Indexed: 02/26/2024]
Abstract
Vestigial organs provide a link between ancient and modern traits and therefore have great potential to resolve the phylogeny of contentious fossils that bear features not seen in extant species. Here we show that extant daddy-longlegs (Arachnida, Opiliones), a group once thought to possess only one pair of eyes, in fact additionally retain a pair of vestigial median eyes and a pair of vestigial lateral eyes. Neuroanatomical gene expression surveys of eye-patterning transcription factors, opsins, and other structural proteins in the daddy-longlegs Phalangium opilio show that the vestigial median and lateral eyes innervate regions of the brain positionally homologous to the median and lateral eye neuropils, respectively, of chelicerate groups like spiders and horseshoe crabs. Gene silencing of eyes absent shows that the vestigial eyes are under the control of the retinal determination gene network. Gene silencing of dachshund disrupts the lateral eyes, but not the median eyes, paralleling loss-of-function phenotypes in insect models. The existence of lateral eyes in extant daddy-longlegs bears upon the placement of the oldest harvestmen fossils, a putative stem group that possessed both a pair of median eyes and a pair of lateral eyes. Phylogenetic analysis of harvestman relationships with an updated understanding of lateral eye incidence resolved the four-eyed fossil group as a member of the extant daddy-longlegs suborder, which in turn resulted in older estimated ages of harvestman diversification. This work underscores that developmental vestiges in extant taxa can influence our understanding of character evolution, placement of fossils, and inference of divergence times.
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Affiliation(s)
- Guilherme Gainett
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA.
| | - Benjamin C Klementz
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Pola Blaszczyk
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Emily V W Setton
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Gabriel P Murayama
- Laboratório de Ecologia Sensorial e Comportamento de Artrópodes, Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Béttio, 1000, Ermelino Matarazzo, São Paulo, SP 03828-000, Brazil
| | - Rodrigo Willemart
- Laboratório de Ecologia Sensorial e Comportamento de Artrópodes, Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, Rua Arlindo Béttio, 1000, Ermelino Matarazzo, São Paulo, SP 03828-000, Brazil
| | - Efrat Gavish-Regev
- The National Natural History Collections, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem 9190401, Israel
| | - Prashant P Sharma
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
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2
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Jean‐Guillaume CB, Kumar JP. Development of the ocellar visual system in Drosophila melanogaster. FEBS J 2022; 289:7411-7427. [PMID: 35490409 PMCID: PMC9805374 DOI: 10.1111/febs.16468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 03/28/2022] [Accepted: 04/29/2022] [Indexed: 01/14/2023]
Abstract
The adult visual system of the fruit fly, Drosophila melanogaster, contains seven eyes-two compound eyes, a pair of Hofbauer-Buchner eyelets, and three ocelli. Each of these eye types has a specialized and essential role to play in visual and/or circadian behavior. As such, understanding how each is specified, patterned, and wired is of primary importance to vision biologists. Since the fruit fly is amenable to manipulation by an enormous array of genetic and molecular tools, its development is one of the best and most studied model systems. After more than a century of experimental investigations, our understanding of how each eye type is specified and patterned is grossly uneven. The compound eye has been the subject of several thousand studies; thus, our knowledge of its development is the deepest. By comparison, very little is known about the specification and patterning of the other two visual systems. In this Viewpoint article, we will describe what is known about the function and development of the Drosophila ocelli.
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3
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Friedrich M. Coming into clear sight at last: Ancestral and derived events during chelicerate visual system development. Bioessays 2022; 44:e2200163. [DOI: 10.1002/bies.202200163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences Wayne State University Detroit Michigan USA
- Department of Ophthalmological, Visual, and Anatomical Sciences, Wayne State University School of Medicine Detroit Michigan USA
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4
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Lavin R, Rathore S, Bauer B, Disalvo J, Mosley N, Shearer E, Elia Z, Cook TA, Buschbeck EK. EyeVolve, a modular PYTHON based model for simulating developmental eye type diversification. Front Cell Dev Biol 2022; 10:964746. [PMID: 36092740 PMCID: PMC9459020 DOI: 10.3389/fcell.2022.964746] [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: 06/08/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
Vision is among the oldest and arguably most important sensory modalities for animals to interact with their external environment. Although many different eye types exist within the animal kingdom, mounting evidence indicates that the genetic networks required for visual system formation and function are relatively well conserved between species. This raises the question as to how common developmental programs are modified in functionally different eye types. Here, we approached this issue through EyeVolve, an open-source PYTHON-based model that recapitulates eye development based on developmental principles originally identified in Drosophila melanogaster. Proof-of-principle experiments showed that this program’s animated timeline successfully simulates early eye tissue expansion, neurogenesis, and pigment cell formation, sequentially transitioning from a disorganized pool of progenitor cells to a highly organized lattice of photoreceptor clusters wrapped with support cells. Further, tweaking just five parameters (precursor pool size, founder cell distance and placement from edge, photoreceptor subtype number, and cell death decisions) predicted a multitude of visual system layouts, reminiscent of the varied eye types found in larval and adult arthropods. This suggests that there are universal underlying mechanisms that can explain much of the existing arthropod eye diversity. Thus, EyeVolve sheds light on common principles of eye development and provides a new computational system for generating specific testable predictions about how development gives rise to diverse visual systems from a commonly specified neuroepithelial ground plan.
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Affiliation(s)
- Ryan Lavin
- Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
| | - Shubham Rathore
- Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
| | - Brian Bauer
- Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
| | - Joe Disalvo
- Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
| | - Nick Mosley
- Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
| | - Evan Shearer
- Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
| | - Zachary Elia
- Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
| | - Tiffany A. Cook
- Center of Molecular Medicine and Genomics, Wayne State University School of Medicine, Detroit, MI, United States
| | - Elke K. Buschbeck
- Biological Sciences, University of Cincinnati, Cincinnati, OH, United States
- *Correspondence: Elke K. Buschbeck,
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5
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Fridman MV, Namiot VA. The Origin of Life in the Context of Inanimate Nature. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921050043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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6
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Falcón J, Torriglia A, Attia D, Viénot F, Gronfier C, Behar-Cohen F, Martinsons C, Hicks D. Exposure to Artificial Light at Night and the Consequences for Flora, Fauna, and Ecosystems. Front Neurosci 2020; 14:602796. [PMID: 33304237 PMCID: PMC7701298 DOI: 10.3389/fnins.2020.602796] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/22/2020] [Indexed: 12/22/2022] Open
Abstract
The present review draws together wide-ranging studies performed over the last decades that catalogue the effects of artificial-light-at-night (ALAN) upon living species and their environment. We provide an overview of the tremendous variety of light-detection strategies which have evolved in living organisms - unicellular, plants and animals, covering chloroplasts (plants), and the plethora of ocular and extra-ocular organs (animals). We describe the visual pigments which permit photo-detection, paying attention to their spectral characteristics, which extend from the ultraviolet into infrared. We discuss how organisms use light information in a way crucial for their development, growth and survival: phototropism, phototaxis, photoperiodism, and synchronization of circadian clocks. These aspects are treated in depth, as their perturbation underlies much of the disruptive effects of ALAN. The review goes into detail on circadian networks in living organisms, since these fundamental features are of critical importance in regulating the interface between environment and body. Especially, hormonal synthesis and secretion are often under circadian and circannual control, hence perturbation of the clock will lead to hormonal imbalance. The review addresses how the ubiquitous introduction of light-emitting diode technology may exacerbate, or in some cases reduce, the generalized ever-increasing light pollution. Numerous examples are given of how widespread exposure to ALAN is perturbing many aspects of plant and animal behaviour and survival: foraging, orientation, migration, seasonal reproduction, colonization and more. We examine the potential problems at the level of individual species and populations and extend the debate to the consequences for ecosystems. We stress, through a few examples, the synergistic harmful effects resulting from the impacts of ALAN combined with other anthropogenic pressures, which often impact the neuroendocrine loops in vertebrates. The article concludes by debating how these anthropogenic changes could be mitigated by more reasonable use of available technology - for example by restricting illumination to more essential areas and hours, directing lighting to avoid wasteful radiation and selecting spectral emissions, to reduce impact on circadian clocks. We end by discussing how society should take into account the potentially major consequences that ALAN has on the natural world and the repercussions for ongoing human health and welfare.
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Affiliation(s)
- Jack Falcón
- Laboratoire Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), MNHN, CNRS FRE 2030, SU, IRD 207, UCN, UA, Paris, France
| | - Alicia Torriglia
- Centre de Recherche des Cordeliers, INSERM U 1138, Ophtalmopole Hôpital Cochin, Assistance Publique - Hôpitaux de Paris, Université de Paris - SU, Paris, France
| | - Dina Attia
- ANSES, French Agency for Food, Environmental and Occupational Health & Safety, Maisons-Alfort, France
| | | | - Claude Gronfier
- Lyon Neuroscience Research Center (CRNL), Waking Team, Inserm UMRS 1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Lyon, France
| | - Francine Behar-Cohen
- Centre de Recherche des Cordeliers, INSERM U 1138, Ophtalmopole Hôpital Cochin, Assistance Publique - Hôpitaux de Paris, Université de Paris - SU, Paris, France
| | | | - David Hicks
- Inserm, CNRS, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France
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Abstract
For centuries, the eye has fascinated scientists and philosophers alike, and as a result the visual system has always been at the forefront of integrating cutting-edge technology in research. We are again at a turning point at which technical advances have expanded the range of organisms we can study developmentally and deepened what we can learn. In this new era, we are finally able to understand eye development in animals across the phylogenetic tree. In this Review, we highlight six areas in comparative visual system development that address questions that are important for understanding the developmental basis of evolutionary change. We focus on the opportunities now available to biologists to study the developmental genetics, cell biology and morphogenesis that underlie the incredible variation of visual organs found across the Metazoa. Although decades of important work focused on gene expression has suggested homologies and potential evolutionary relationships between the eyes of diverse animals, it is time for developmental biologists to move away from this reductive approach. We now have the opportunity to celebrate the differences and diversity in visual organs found across animal development, and to learn what it can teach us about the fundamental principles of biological systems and how they are built.
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Affiliation(s)
- Kristen M Koenig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA 02138, USA
| | - Jeffrey M Gross
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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8
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Abstract
Molecules of the hedgehog (hh) family are involved in the specification and patterning of eyes in vertebrates and invertebrates. These organs, though, are of very different sizes, raising the question of how Hh molecules operate at such different scales. In this paper we discuss the strategies used by Hh to control the development of the two eye types in Drosophila: the large compound eye and the small ocellus. We first describe the distinct ways in which these two eyes develop and the evidence for the key role played by Hh in both; then we consider the potential for variation in the range of action of a "typical" morphogen and measure this range ("characteristic length") for Hh in different organs, including the compound eye and the ocellus. Finally, we describe how different feedback mechanisms are used to extend the Hh range of action to pattern the large and even the small eye. In the ocellus, the basic Hh signaling pathway adds to its dynamics the attenuation of its receptor as cell differentiate. This sole regulatory change can result in the decoding of the Hh gradient by receiving cells as a wave of constant speed. Therefore, in the fly ocellus, the Hh morphogen adds to its spatial patterning role a novel one: patterning along a time axis.
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Hall C, Rodriguez M, Garcia J, Posfai D, DuMez R, Wictor E, Quintero OA, Hill MS, Rivera AS, Hill AL. Secreted frizzled related protein is a target of PaxB and plays a role in aquiferous system development in the freshwater sponge, Ephydatia muelleri. PLoS One 2019; 14:e0212005. [PMID: 30794564 PMCID: PMC6386478 DOI: 10.1371/journal.pone.0212005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 01/25/2019] [Indexed: 12/19/2022] Open
Abstract
Canonical and non-canonical Wnt signaling, as well as the Pax/Six gene network, are involved in patterning the freshwater sponge aquiferous system. Using computational approaches to identify transcription factor binding motifs in a freshwater sponge genome, we located putative PaxB binding sites near a Secreted Frizzled Related Protein (SFRP) gene in Ephydatia muelleri. EmSFRP is expressed throughout development, but with highest levels in juvenile sponges. In situ hybridization and antibody staining show EmSFRP expression throughout the pinacoderm and choanoderm in a subpopulation of amoeboid cells that may be differentiating archeocytes. Knockdown of EmSFRP leads to ectopic oscula formation during development, suggesting that EmSFRP acts as an antagonist of Wnt signaling in E. muelleri. Our findings support a hypothesis that regulation of the Wnt pathway by the Pax/Six network as well as the role of Wnt signaling in body plan morphogenesis was established before sponges diverged from the rest of the metazoans.
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Affiliation(s)
- Chelsea Hall
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Melanie Rodriguez
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Josephine Garcia
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Dora Posfai
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Rachel DuMez
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Erik Wictor
- Department of Biological Sciences, University of the Pacific, Stockton, California, United States of America
| | - Omar A. Quintero
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
| | - Malcolm S. Hill
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
- Department of Biology, Bates College, Lewiston, Maine, United States of America
| | - Ajna S. Rivera
- Department of Biological Sciences, University of the Pacific, Stockton, California, United States of America
| | - April L. Hill
- Department of Biology, University of Richmond, Richmond, Virginia, United States of America
- Department of Biology, Bates College, Lewiston, Maine, United States of America
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10
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Stahl AL, Baucom RS, Cook TA, Buschbeck EK. A Complex Lens for a Complex Eye. Integr Comp Biol 2018; 57:1071-1081. [PMID: 28992245 DOI: 10.1093/icb/icx116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
A key innovation for high resolution eyes is a sophisticated lens that precisely focuses light onto photoreceptors. The eyes of holometabolous larvae range from very simple eyes that merely detect light to eyes that are capable of high spatial resolution. Particularly interesting are the bifocal lenses of Thermonectus marmoratus larvae, which differentially focus light on spectrally-distinct retinas. While functional aspects of insect lenses have been relatively well studied, little work has explored their molecular makeup, especially in regard to more complex eye types. To investigate this question, we took a transcriptomic and proteomic approach to identify the major proteins contributing to the principal bifocal lenses of T. marmoratus larvae. Mass spectrometry revealed 10 major lens proteins. Six of these share sequence homology with cuticular proteins, a large class of proteins that are also major components of corneal lenses from adult compound eyes of Drosophila melanogaster and Anopheles gambiae. Two proteins were identified as house-keeping genes and the final two lack any sequence homologies to known genes. Overall the composition seems to follow a pattern of co-opting transparent and optically dense proteins, similar to what has been described for other animal lenses. To identify cells responsible for the secretion of specific lens proteins, we performed in situ hybridization studies and found some expression differences between distal and proximal corneagenous cells. Since the distal cells likely give rise to the periphery and the proximal cells to the center of the lens, our findings highlight a possible mechanism for establishing structural differences that are in line with the bifocal nature of these lenses. A better understanding of lens composition provides insights into the evolution of proper focusing, which is an important step in the transition between low-resolution and high-resolution eyes.
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Affiliation(s)
- Aaron L Stahl
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Regina S Baucom
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tiffany A Cook
- Wayne State University School of Medicine, Center of Molecular Medicine and Genomics, Detroit, MI 48201, USA
| | - Elke K Buschbeck
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
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11
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Boyan G, Graf P, Ehrhardt E. Patterns of cell death in the embryonic antenna of the grasshopper Schistocerca gregaria. Dev Genes Evol 2018; 228:105-118. [PMID: 29511851 DOI: 10.1007/s00427-018-0607-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 02/22/2018] [Indexed: 12/27/2022]
Abstract
We have investigated the pattern of apoptosis in the antennal epithelium during embryonic development of the grasshopper Schistocerca gregaria. The molecular labels lachesin and annulin reveal that the antennal epithelium becomes subdivided into segment-like meristal annuli within which sensory cell clusters later differentiate. To determine whether apoptosis is involved in the development of such sensory cell clusters, we examined the expression pattern of the cell death labels acridine orange and TUNEL in the epithelium. We found stereotypic, age-dependent, wave-like patterns of cell death in the antenna. Early in embryogenesis, apoptosis is restricted to the most basal meristal annuli but subsequently spreads to encompass almost the entire antenna. Cell death then declines in more basal annuli and is only found in the tip region later in embryogenesis. Apoptosis is restricted throughout to the midregion of a given annulus and away from its border with neighboring annuli, arguing against a causal role in annular formation. Double-labeling for cell death and sensory cell differentiation reveals apoptosis occurring within bands of differentiating sensory cell clusters, matching the meristal organization of the apical antenna. Examination of the individual epithelial lineages which generate sensory cells reveals that apoptosis begins peripherally within a lineage and with age expands to encompass the differentiated sensory cell at the base. We conclude that complete lineages can undergo apoptosis and that the youngest cells in these lineages appear to die first, with the sensory neuron dying last. Lineage-based death in combination with cell death patterns in different regions of the antenna may contribute to odor-mediated behaviors in the grasshopper.
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Affiliation(s)
- George Boyan
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität, Grosshadernerstrasse 2 Martinsried, 82152, Planegg, Germany.
| | - Philip Graf
- Janelia Farm Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Erica Ehrhardt
- Section of Neurobiology, Department of Biology II, Biocenter, Ludwig-Maximilians-Universität, Grosshadernerstrasse 2 Martinsried, 82152, Planegg, Germany
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12
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Byrne M, Koop D, Morris VB, Chui J, Wray GA, Cisternas P. Expression of genes and proteins of the pax-six-eya-dach network in the metamorphic sea urchin: Insights into development of the enigmatic echinoderm body plan and sensory structures. Dev Dyn 2017; 247:239-249. [PMID: 28850769 DOI: 10.1002/dvdy.24584] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 07/25/2017] [Accepted: 07/31/2017] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Photoreception-associated genes of the Pax-Six-Eya-Dach network (PSEDN) are deployed for many roles in addition to photoreception development. In this first study of PSEDN genes during development of the pentameral body in sea urchins, we investigated their spatial expression in Heliocidaris erythrogramma. RESULTS Expression of PSEDN genes in the hydrocoele of early (Dach, Eya, Six1/2) and/or late (Pax6, Six3/6) larvae, and the five hydrocoele lobes, the first morphological expression of pentamery, supports a role in body plan development. Pax6, Six1/2, and Six3/6 were localized to the primary and/or secondary podia and putative sensory/neuronal cells. Six1/2 and Six3/6 were expressed in the neuropil region in the terminal disc of the podia. Dach was localized to spines. Sequential up-regulation of gene expression as new podia and spines formed was evident. Rhabdomeric opsin and pax6 protein were localized to cells in the primary podia and spines. CONCLUSIONS Our results support roles for PSEDN genes in development of the pentameral body plan, contributing to our understanding of how the most unusual body plan in the Bilateria may have evolved. Development of sensory cells within the Pax-Six expression field is consistent with the role of these genes in sensory cell development in diverse species. Developmental Dynamics 247:239-249, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Maria Byrne
- School of Medical Sciences, The University of Sydney, NSW, Australia.,School of Life and Environmental Sciences, The University of Sydney, NSW, Australia
| | - Demian Koop
- School of Medical Sciences, The University of Sydney, NSW, Australia
| | - Valerie B Morris
- School of Life and Environmental Sciences, The University of Sydney, NSW, Australia
| | - Juanita Chui
- School of Medical Sciences, The University of Sydney, NSW, Australia
| | - Gregory A Wray
- Department of Biology and Center for Genomic and Computational Biology, Duke University, Durham, North Carolina
| | - Paula Cisternas
- School of Medical Sciences, The University of Sydney, NSW, Australia
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Morehouse NI, Buschbeck EK, Zurek DB, Steck M, Porter ML. Molecular Evolution of Spider Vision: New Opportunities, Familiar Players. THE BIOLOGICAL BULLETIN 2017; 233:21-38. [PMID: 29182503 DOI: 10.1086/693977] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Spiders are among the world's most species-rich animal lineages, and their visual systems are likewise highly diverse. These modular visual systems, composed of four pairs of image-forming "camera" eyes, have taken on a huge variety of forms, exhibiting variation in eye size, eye placement, image resolution, and field of view, as well as sensitivity to color, polarization, light levels, and motion cues. However, despite this conspicuous diversity, our understanding of the genetic underpinnings of these visual systems remains shallow. Here, we review the current literature, analyze publicly available transcriptomic data, and discuss hypotheses about the origins and development of spider eyes. Our efforts highlight that there are many new things to discover from spider eyes, and yet these opportunities are set against a backdrop of deep homology with other arthropod lineages. For example, many (but not all) of the genes that appear important for early eye development in spiders are familiar players known from the developmental networks of other model systems (e.g., Drosophila). Similarly, our analyses of opsins and related phototransduction genes suggest that spider photoreceptors employ many of the same genes and molecular mechanisms known from other arthropods, with a hypothesized ancestral spider set of four visual and four nonvisual opsins. This deep homology provides a number of useful footholds into new work on spider vision and the molecular basis of its extant variety. We therefore discuss what some of these first steps might be in the hopes of convincing others to join us in studying the vision of these fascinating creatures.
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Key Words
- AL, anterior lateral
- AM, anterior median
- BLAST, Basic Local Alignment Search Tool
- CNS, central nervous system
- KAAS, KEGG Automatic Annotation Server
- KEGG, Kyoto Encyclopedia of Genes and Genomes
- LWS, long wavelength sensitive
- MAFFT, Multiple Alignment using Fast Fourier Transform
- MWS, middle wavelength sensitive
- PL, posterior lateral
- PM, posterior median
- RAxML, Randomized Axelerated Maximum Likelihood
- UVS, ultraviolet sensitive
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14
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5D imaging via light sheet microscopy reveals cell dynamics during the eye-antenna disc primordium formation in Drosophila. Sci Rep 2017; 7:44945. [PMID: 28322328 PMCID: PMC5359570 DOI: 10.1038/srep44945] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 02/14/2017] [Indexed: 01/05/2023] Open
Abstract
5D images of engrailed (en) and eye gone (eyg) gene expressions during the course of the eye-antenna disc primordium (EADP) formation of Drosophila embryos from embryonic stages 13 through 16 were recorded via light sheet microscopy and analyzed to reveal the cell dynamics involved in the development of the EADP. Detailed analysis of the time-lapsed images revealed the process of EADP formation and its invagination trajectory, which involved an inversion of the EADP anterior-posterior axis relative to the body. Furthermore, analysis of the en-expression pattern in the EADP provided strong evidence that the EADP is derived from one of the en-expressing head segments.
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15
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Yuan H, Wang W, Hu B, Pan C, Chen M, Ke L, Yang L, Chen J. Cloning and Functional Analysis of Pax6 from the Hydrothermal Vent Tubeworm Ridgeia piscesae. PLoS One 2016; 11:e0168579. [PMID: 28005979 PMCID: PMC5179022 DOI: 10.1371/journal.pone.0168579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 12/02/2016] [Indexed: 12/04/2022] Open
Abstract
The paired box 6 (Pax6) gene encodes a transcription factor essential for eye development in a wide range of animal lineages. Here we describe the cloning and characterization of Pax6 gene from the blind hydrothermal vent tubeworm Ridgeia piscesae (RpPax6). The deduced RpPax6 protein shares extensive sequence identity with Pax6 proteins from other species and contains both the paired domain and a complete homeodomain. Phylogenetic analysis indicates that it clusters with the corresponding sequence from the closely related species Platynereis dumerilii (P. dumerilii) of Annelida. Luciferase reporter assay indicate that RpPax6 protein suppresses the transcription of sine oculis (so) in D. melanogaster, interfering with the C-terminal of RpPax6. Taking advantage of Drosophila model, we show that RpPax6 expression is not able to rescue small eye phenotype of ey2 mutant, only to cause a more severe headless phenotype. In addition, RpPax6 expression induced apoptosis and inhibition of apoptosis can partially rescue RpPax6-induced headless phenotype. We provide evidence RpPax6 plays at least two roles: it blocks the expression of later-acting transcription factors in the eye development cascade, and it promotes cell apoptosis. Our results indicate alternation of the Pax6 function may be one of the possible causes that lead the eye absence in vestimentiferan tubeworms.
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Affiliation(s)
- Huifang Yuan
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
| | - Wei Wang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
- * E-mail: (JC); (WW)
| | - Bin Hu
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
| | - Changkun Pan
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
- School of Marine Sciences, Ningbo University, Ningbo, Zhejiang, China
| | - Mingliang Chen
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
| | - Linlin Ke
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
| | - Lirong Yang
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
| | - Jianming Chen
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, Fujian Province, China
- * E-mail: (JC); (WW)
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Zhou Q, Yu L, Friedrich M, Pignoni F. Distinct regulation of atonal in a visual organ of Drosophila: Organ-specific enhancer and lack of autoregulation in the larval eye. Dev Biol 2016; 421:67-76. [PMID: 27693434 DOI: 10.1016/j.ydbio.2016.09.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 04/15/2016] [Accepted: 09/28/2016] [Indexed: 01/23/2023]
Abstract
Drosophila has three types of visual organs, the larval eyes or Bolwig's organs (BO), the ocelli (OC) and the compound eyes (CE). In all, the bHLH protein Atonal (Ato) functions as the proneural factor for photoreceptors and effects the transition from progenitor cells to differentiating neurons. In this work, we investigate the regulation of ato expression in the BO primordium (BOP). Surprisingly, we find that ato transcription in the BOP is entirely independent of the shared regulatory DNA for the developing CE and OC. The core enhancer for BOP expression, atoBO, lies ~6kb upstream of the ato gene, in contrast to the downstream location of CE and OC regulatory elements. Moreover, maintenance of ato expression in the neuronal precursors through autoregulation-a common and ancient feature of ato expression that is well-documented in eyes, ocelli and chordotonal organs-does not occur in the BO. We also show that the atoBO enhancer contains two binding sites for the transcription factor Sine oculis (So), a core component of the progenitor specification network in all three visual organs. These binding sites function in vivo and are specifically bound by So in vitro. Taken together, our findings reveal that the control of ato transcription in the evolutionarily derived BO has diverged considerably from ato regulation in the more ancestral compound eyes and ocelli, to the extent of acquiring what appears to be a distinct and evolutionarily novel cis-regulatory module.
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Affiliation(s)
- Qingxiang Zhou
- Department of Ophthalmology and Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Linlin Yu
- Department of Ophthalmology and Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Markus Friedrich
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Francesca Pignoni
- Department of Ophthalmology and Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY, USA; Departments of Neuroscience & Physiology and Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA.
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Marco Antonio DS, Hartfelder K. Toward an Understanding of Divergent Compound Eye Development in Drones and Workers of the Honeybee (Apis melliferaL.): A Correlative Analysis of Morphology and Gene Expression. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2016; 328:139-156. [DOI: 10.1002/jez.b.22696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 08/17/2016] [Accepted: 08/21/2016] [Indexed: 12/27/2022]
Affiliation(s)
- David S. Marco Antonio
- Departamento de Genética; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto SP Brazil
| | - Klaus Hartfelder
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos; Faculdade de Medicina de Ribeirão Preto; Universidade de São Paulo; Ribeirão Preto SP Brazil
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Zhou Q, DeSantis DF, Friedrich M, Pignoni F. Shared and distinct mechanisms of atonal regulation in Drosophila ocelli and compound eyes. Dev Biol 2016; 418:10-16. [PMID: 27565023 DOI: 10.1016/j.ydbio.2016.08.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 01/04/2023]
Abstract
The fruit fly Drosophila melanogaster has two types of external visual organs, a pair of compound eyes and a group of three ocelli. At the time of neurogenesis, the proneural transcription factor Atonal mediates the transition from progenitor cells to differentiating photoreceptor neurons in both organs. In the developing compound eye, atonal (ato) expression is directly induced by transcriptional regulators that confer retinal identity, the Retinal Determination (RD) factors. Little is known, however, about control of ato transcription in the ocelli. Here we show that a 2kb genomic DNA fragment contains distinct and common regulatory elements necessary for ato induction in compound eyes and ocelli. The three binding sites that mediate direct regulation by the RD factors Sine oculis and Eyeless in the compound eye are also required in the ocelli. However, in the latter, these sites mediate control by Sine oculis and the other Pax6 factor of Drosophila, Twin of eyeless, which can bind the Pax6 sites in vitro. Moreover, the three sites are differentially utilized in the ocelli: all three are similarly essential for atonal induction in the posterior ocelli, but show considerable redundancy in the anterior ocellus. Strikingly, this difference parallels the distinct control of ato transcription in the posterior and anterior progenitors of the developing compound eyes. From a comparative perspective, our findings suggest that the ocelli of arthropods may have originated through spatial partitioning from the dorsal edge of an ancestral compound eye.
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Affiliation(s)
- Qingxiang Zhou
- Department of Ophthalmology and Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Dana F DeSantis
- Department of Ophthalmology and Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Markus Friedrich
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, Detroit, MI 48201, USA
| | - Francesca Pignoni
- Department of Ophthalmology and Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA.
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Kaya M, Sargin I, Al-jaf I, Erdogan S, Arslan G. Characteristics of corneal lens chitin in dragonfly compound eyes. Int J Biol Macromol 2016; 89:54-61. [DOI: 10.1016/j.ijbiomac.2016.04.056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/12/2016] [Accepted: 04/19/2016] [Indexed: 12/19/2022]
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Stecher N, Stowasser A, Stahl A, Buschbeck EK. Embryonic development of the larval eyes of the Sunburst Diving Beetle, Thermonectus marmoratus (Insecta: Dytiscidae): a morphological study. Evol Dev 2016; 18:216-28. [PMID: 27402568 DOI: 10.1111/ede.12192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Stemmata, the larval eyes of holometabolous insects are extremely diverse, ranging from full compound eyes, to a few ommatidial units as are typical in compound eyes, to sophisticated and functionally specialized image-forming camera-type eyes. Stemmata evolved from a compound eye ommatidial ancestor, an eye type that is morphologically well conserved in regards to cellular composition, and well studied in regards to development. However, despite this evolutionary origin it remains largely unknown how stemmata develop. In addition, it is completely unclear how development is altered to give rise to some of the functionally most complex stemmata, such as those of the sunburst diving beetle, Thermonectus marmoratus. In this study, we used histological methods to investigate the embryonic development of the functionally complex principal stemmata Eye 1 and Eye 2 of the larval visual system of T. marmoratus. To gain insights into how cellular components of their sophisticated camera-type eyes might have evolved from the cellular components of ommatidial ancestors, we contrast our findings against known features of ommatidia development, which are particularly well understood in Drosophila. We find many similarities, such as the early presence of a pseudostratified epithelium, and the order in which specific cell types are recruited. However, in Thermonectus each cell type is represented by a large number of cells from early on and major tissue re-orientation occurs as eye development progresses. This study provides insights into the timing of morphological features and represents the basis for future molecular studies.
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Affiliation(s)
- Nadine Stecher
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, 45221, USA.,Department of Sciences, Wentworth Institute of Technology, Boston, MA, 02115, USA
| | - Annette Stowasser
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Aaron Stahl
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, 45221, USA
| | - Elke K Buschbeck
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, 45221, USA
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Evolution of mammalian sound localization circuits: A developmental perspective. Prog Neurobiol 2016; 141:1-24. [PMID: 27032475 DOI: 10.1016/j.pneurobio.2016.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 02/27/2016] [Accepted: 02/27/2016] [Indexed: 01/06/2023]
Abstract
Localization of sound sources is a central aspect of auditory processing. A unique feature of mammals is the smooth, tonotopically organized extension of the hearing range to high frequencies (HF) above 10kHz, which likely induced positive selection for novel mechanisms of sound localization. How this change in the auditory periphery is accompanied by changes in the central auditory system is unresolved. I will argue that the major VGlut2(+) excitatory projection neurons of sound localization circuits (dorsal cochlear nucleus (DCN), lateral and medial superior olive (LSO and MSO)) represent serial homologs with modifications, thus being paramorphs. This assumption is based on common embryonic origin from an Atoh1(+)/Wnt1(+) cell lineage in the rhombic lip of r5, same cell birth, a fusiform cell morphology, shared genetic components such as Lhx2 and Lhx9 transcription factors, and similar projection patterns. Such a parsimonious evolutionary mechanism likely accelerated the emergence of neurons for sound localization in all three dimensions. Genetic analyses indicate that auditory nuclei in fish, birds, and mammals receive contributions from the same progenitor lineages. Anatomical and physiological differences and the independent evolution of tympanic ears in vertebrate groups, however, argue for convergent evolution of sound localization circuits in tetrapods (amphibians, reptiles, birds, and mammals). These disparate findings are discussed in the context of the genetic architecture of the developing hindbrain, which facilitates convergent evolution. Yet, it will be critical to decipher the gene regulatory networks underlying development of auditory neurons across vertebrates to explore the possibility of homologous neuronal populations.
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Pax6 in Collembola: Adaptive Evolution of Eye Regression. Sci Rep 2016; 6:20800. [PMID: 26856893 PMCID: PMC4746759 DOI: 10.1038/srep20800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 01/12/2016] [Indexed: 11/12/2022] Open
Abstract
Unlike the compound eyes in insects, collembolan eyes are comparatively simple: some species have eyes with different numbers of ocelli (1 + 1 to 8 + 8), and some species have no apparent eye structures. Pax6 is a universal master control gene for eye morphogenesis. In this study, full-length Pax6 cDNAs, Fc-Pax6 and Cd-Pax6, were cloned from an eyeless collembolan (Folsomia candida, soil-dwelling) and an eyed one (Ceratophysella denticulata, surface-dwelling), respectively. Their phylogenetic positions are between the two Pax6 paralogs in insects, eyeless (ey) and twin of eyeless (toy), and their protein sequences are more similar to Ey than to Toy. Both Fc-Pax6 and Cd-Pax6 could induce ectopic eyes in Drosophila, while Fc-Pax6 exhibited much weaker transactivation ability than Cd-Pax6. The C-terminus of collembolan Pax6 is indispensable for its transactivation ability, and determines the differences of transactivation ability between Fc-Pax6 and Cd-Pax6. One of the possible reasons is that Fc-Pax6 accumulated more mutations at some key functional sites of C-terminus under a lower selection pressure on eye development due to the dark habitats of F. candida. The composite data provide a first molecular evidence for the monophyletic origin of collembolan eyes, and indicate the eye degeneration of collembolans is caused by adaptive evolution.
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Buschbeck EK. Escaping compound eye ancestry: the evolution of single-chamber eyes in holometabolous larvae. ACTA ACUST UNITED AC 2015; 217:2818-24. [PMID: 25122913 DOI: 10.1242/jeb.085365] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Stemmata, the eyes of holometabolous insect larvae, have gained little attention, even though they exhibit remarkably different optical solutions, ranging from compound eyes with upright images, to sophisticated single-chamber eyes with inverted images. Such optical differences raise the question of how major transitions may have occurred. Stemmata evolved from compound eye ancestry, and optical differences are apparent even in some of the simplest systems that share strong cellular homology with adult ommatidia. The transition to sophisticated single-chamber eyes occurred many times independently, and in at least two different ways: through the fusion of many ommatidia [as in the sawfly (Hymenoptera)], and through the expansion of single ommatidia [as in tiger beetles (Coleoptera), antlions (Neuroptera) and dobsonflies (Megaloptera)]. Although ommatidia-like units frequently have multiple photoreceptor layers (tiers), sophisticated image-forming stemmata tend to only have one photoreceptor tier, presumably a consequence of the lens only being able to efficiently focus light on to one photoreceptor layer. An interesting exception is found in some diving beetles [Dytiscidae (Coleoptera)], in which two retinas receive sharp images from a bifocal lens. Taken together, stemmata represent a great model system to study an impressive set of optical solutions that evolved from a relatively simple ancestral organization.
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Affiliation(s)
- Elke K Buschbeck
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221-0006, USA
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Molecular characterization and embryonic origin of the eyes in the common house spider Parasteatoda tepidariorum. EvoDevo 2015; 6:15. [PMID: 26034574 PMCID: PMC4450840 DOI: 10.1186/s13227-015-0011-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/10/2015] [Indexed: 01/30/2023] Open
Abstract
Background Two visual systems are present in most arthropod groups: median and lateral eyes. Most of our current knowledge about the developmental and molecular mechanisms involved in eye formation in arthropods comes from research in the model system Drosophila melanogaster. Here, a core set of retinal determination genes, namely, sine-oculis (so), eyes absent (eya), dachshund (dac), and the two pax6 orthologues eyeless (ey) and twin of eyeless (toy) govern early retinal development. By contrast, not much is known about the development of the up-to-eight eyes present in spiders. Therefore, we analyzed the embryonic expression of core retinal determination genes in the common house spider Parasteatoda tepidariorum. Results We show that the anlagen of the median and lateral eyes in P. tepidariorum originate from different regions of the non-neurogenic ectoderm in the embryonic head. The median eyes are specified as two individual anlagen in an anterior median position in the developing head and subsequently move to their final position following extensive morphogenetic movements of the non-neurogenic ectoderm. The lateral eyes develop from a more lateral position. Intriguingly, they are specified as a unique field of cells that splits into the three individual lateral eyes during late embryonic development. Using gene expression analyses, we identified a unique combination of determination gene expression in the anlagen of the lateral and median eyes, respectively. Conclusions This study of retinal determination genes in the common house spider P. tepidariorum represents the first comprehensive analysis of the well-known retinal determination genes in arthropods outside insects. The development of the individual lateral eyes via the subdivision of one single eye primordium might be the vestige of a larger composite eye anlage, and thus supports the notion that the composite eye is the plesiomorphic state of the lateral eyes in arthropods. The molecular distinction of the two visual systems is similar to the one described for compound eyes and ocelli in Drosophila, suggesting that a unique core determination network for median and lateral eyes, respectively, might have been in place already in the last common ancestor of spiders and insects. Electronic supplementary material The online version of this article (doi:10.1186/s13227-015-0011-9) contains supplementary material, which is available to authorized users.
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Samadi L, Schmid A, Eriksson BJ. Differential expression of retinal determination genes in the principal and secondary eyes of Cupiennius salei Keyserling (1877). EvoDevo 2015; 6:16. [PMID: 26034575 PMCID: PMC4450993 DOI: 10.1186/s13227-015-0010-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/10/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transcription factors that determine retinal development seem to be conserved in different phyla throughout the animal kingdom. In most representatives, however, only a few of the involved transcription factors have been sampled and many animal groups remain understudied. In order to fill in the gaps for the chelicerate group of arthropods, we tested the expression pattern of the candidate genes involved in the eye development in the embryo of the wandering spider Cupiennius salei. One main objective was to profile the molecular development of the eyes and to search for possible variation among eye subtype differentiation. A second aim was to form a basis for comparative studies in order to elucidate evolutionary pathways in eye development. RESULTS We screened the spider embryonic transcriptome for retina determination gene candidates and discovered that all except one of the retinal determination genes have been duplicated. Gene expression analysis shows that the two orthologs of all the genes have different expression patterns. The genes are mainly expressed in the developing optic neuropiles of the eyes (lateral furrow, mushroom body, arcuate body) in earlier stages of development (160 to 220 h after egg laying). Later in development (180 to 280 h after egg laying), there is differential expression of the genes in disparate eye vesicles; for example, Cs-otxa is expressed only in posterior-lateral eye vesicles, Cs-otxb, Cs-six1a, and Cs-six3b in all three secondary eye vesicles, Cs-pax6a only in principal eye vesicles, Cs-six1b in posterior-median, and posterior-lateral eye vesicles, and Cs-six3a in lateral and principal eye vesicles. CONCLUSIONS Principle eye development shows pax6a (ey) expression, suggesting pax6 dependence, although secondary eyes develop independently of pax6 genes and show differential expression of several retinal determination genes. Comparing this with the other arthropods suggests that pax6-dependent median eye development is a ground pattern of eye development in this group and that the ocelli of insects, the median eyes of chelicerates, and nauplius eyes can be homologised. The expression pattern of the investigated genes makes it possible to distinguish between secondary eyes and principal eyes. Differences of gene expression among the different lateral eyes indicate disparate function combined with genetic drift.
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Affiliation(s)
- Leyli Samadi
- Department of Neurobiology, Centre for Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Axel Schmid
- Department of Neurobiology, Centre for Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
| | - Bo Joakim Eriksson
- Department of Neurobiology, Centre for Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstraße 14, 1090 Vienna, Austria
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Domínguez-Cejudo MA, Casares F. Antero-posterior patterning of Drosophila ocelli requires an anti-repressor mechanism within the hh-pathway mediated by the Six3 gene Optix. Development 2015; 142:2801-9. [DOI: 10.1242/dev.125179] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 06/29/2015] [Indexed: 12/23/2022]
Abstract
In addition to the compound eyes, most insects possess a set of three dorsal ocelli that develop at the vertices of a triangular cuticle patch, forming the ocellar complex. The wingless and hedgehog signaling pathways, together with the transcription factor encoded by orthodenticle, are known to play major roles in the specification and patterning of the ocellar complex. Specifically, hedgehog is responsible for the choice between ocellus and cuticle fates within the ocellar complex primordium. However, the interaction between signals and transcription factors known to date do not fully explain how this choice is controlled. We show that this binary choice depends on dynamic changes in the domains of hedgehog signaling. In this dynamics, the restricted expression of engrailed, a hedgehog-signaling target, is key because it defines a domain within the complex where hh transcription is maintained while the pathway activity is blocked. We show that the Drosophila Six3, Optix, is expressed in and required for the development of the anterior ocellus specifically. Optix would not act as an ocellar selector, but rather as a patterning gene, limiting the en expression domain. Our results indicate that, despite their genetic and structural similarity, anterior and posterior ocelli are under different genetic control.
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Affiliation(s)
- M. A. Domínguez-Cejudo
- CABD (Andalusian Centre for Developmental Biology), CSIC-Universidad Pablo de Olavide-Junta de Andalucía. Campus UPO, Ctra. Utrera km1, 41013, Sevilla, SPAIN
| | - F. Casares
- CABD (Andalusian Centre for Developmental Biology), CSIC-Universidad Pablo de Olavide-Junta de Andalucía. Campus UPO, Ctra. Utrera km1, 41013, Sevilla, SPAIN
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Luan Q, Chen Q, Friedrich M. The Pax6 genes eyeless and twin of eyeless are required for global patterning of the ocular segment in the Tribolium embryo. Dev Biol 2014; 394:367-81. [PMID: 25149513 DOI: 10.1016/j.ydbio.2014.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 06/23/2014] [Accepted: 08/06/2014] [Indexed: 01/08/2023]
Abstract
The transcription factor gene Pax6 is widely considered a master regulator of eye development in bilaterian animals. However, the existence of visual organs that develop without Pax6 input and the considerable pleiotropy of Pax6 outside the visual system dictate further studies into defining ancestral functions of this important regulator. Previous work has shown that the combinatorial knockdown of the insect Pax6 orthologs eyeless (ey) and twin of eyeless (toy) perturbs the development of the visual system but also other areas of the larval head in the red flour beetle Tribolium castaneum. To elucidate the role of Pax6 during Tribolium head development in more detail, we studied head cuticle morphology, brain anatomy, embryonic head morphogenesis, and developmental marker gene expression in combinatorial ey and toy knockdown animals. Our experiments reveal that Pax6 is broadly required for patterning the anterior embryonic head. One of the earliest detectable roles is the formation of the embryonic head lobes, which originate from within the ocular segment and give rise to large parts of the supraesophageal brain including the mushroom body, a part of the posterior head capsule cuticle, and the visual system. We present further evidence that toy continues to be required for the development of the larval eyes after formation of the embryonic head lobes in cooperation with the eye developmental transcription factor dachshund (dac). The sum of our findings suggests that Pax6 functions as a competence factor throughout the development of the insect ocular segment. Comparative evidence identifies this function as an ancestral aspect of bilaterian head development.
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Affiliation(s)
- Qing Luan
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA; Institute of Molecular Biology and Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403, USA
| | - Qing Chen
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA
| | - Markus Friedrich
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA; Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201, USA.
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Fortunato SA, Leininger S, Adamska M. Evolution of the Pax-Six-Eya-Dach network: the calcisponge case study. EvoDevo 2014; 5:23. [PMID: 25002963 PMCID: PMC4083861 DOI: 10.1186/2041-9139-5-23] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/15/2014] [Indexed: 12/21/2022] Open
Abstract
Background The Pax-Six-Eya-Dach network (PSEDN) is involved in a variety of developmental processes, including well documented roles in determination of sensory organs and morphogenesis in bilaterian animals. Expression of PSEDN components in cnidarians is consistent with function in sensory organ development. Recent work in demosponges demonstrated the presence of single homologs of Pax and Six genes, and their possible involvement in morphogenesis, but the absence of the remaining network components. Calcisponges are evolutionarily distant from demosponges, and the developmental toolkits of these two lineages differ significantly. We used an emerging model system, Sycon ciliatum, to identify components of the PSEDN and study their expression during embryonic and postembryonic development. Results We identified two Pax, three Six and one Eya genes in calcisponges, a situation strikingly different than in the previously studied demosponges. One of the calcisponge Pax genes can be identified as PaxB, while the second Pax gene has no clear affiliation. The three calcisponge Six genes could not be confidently classified within any known family of Six genes. Expression analysis in adult S. ciliatum demonstrated that representatives of Pax, Six and Eya are expressed in patterns consistent with roles in morphogenesis of the choanocyte chambers. Distinct paralogues of Pax and Six genes were expressed early in the development of the putative larval sensory cells, the cruciform cells. While lack of known photo pigments in calcisponge genomes precludes formal assignment of function to the cruciform cells, we also show that they express additional eumetazoan genes involved in specification of sensory and neuronal cells: Elav and Msi. Conclusions Our results indicate that the role of a Pax-Six-Eya network in morphogenesis likely predates the animal divergence. In addition, Pax and Six, as well as Elav and Msi are expressed during differentiation of cruciform cells, which are good candidates for being sensory cells of the calcaronean sponge larvae.
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Affiliation(s)
- Sofia Av Fortunato
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt. 55, Bergen 5008, Norway ; Department of Biology, University of Bergen, Thormøhlensgt. 55, Bergen 5008, Norway
| | - Sven Leininger
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt. 55, Bergen 5008, Norway ; Current address: Institute of Marine Research, Nordnesgaten 50, Bergen 5005, Norway
| | - Maja Adamska
- Sars International Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt. 55, Bergen 5008, Norway
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Eriksson BJ, Samadi L, Schmid A. The expression pattern of the genes engrailed, pax6, otd and six3 with special respect to head and eye development in Euperipatoides kanangrensis Reid 1996 (Onychophora: Peripatopsidae). Dev Genes Evol 2013; 223:237-46. [PMID: 23625086 PMCID: PMC3781328 DOI: 10.1007/s00427-013-0442-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/15/2013] [Indexed: 11/29/2022]
Abstract
The genes otd/otx, six3, pax6 and engrailed are involved in eye patterning in many animals. Here, we describe the expression pattern of the homologs to otd/otx, six3, pax6 and engrailed in the developing Euperipatoides kanangrensis embryos. Special reference is given to the expression in the protocerebral/ocular region. E. kanangrensis otd is expressed in the posterior part of the protocerebral/ocular segment before, during and after eye invagination. E. kanangrensis otd is also expressed segmentally in the developing ventral nerve cord. The E. kanangrensis six3 is located at the extreme anterior part of the protocerebral/ocular segment and not at the location of the developing eyes. Pax6 is expressed in a broad zone at the posterior part of the protocerebral/ocular segment but only weak expression can be seen at the early onset of eye invagination. In late stages of development, the expression in the eye is upregulated. Pax6 is also expressed in the invaginating hypocerebral organs, thus supporting earlier suggestions that the hypocerebral organs in onychophorans are glands. Pax6 transcripts are also present in the developing ventral nerve cord. The segment polarity gene engrailed is expressed at the dorsal side of the developing eye including only a subset of the cells of the invaginating eye vesicle. We show that engrailed is not expressed in the neuroectoderm of the protocerebral/ocular segment as in the other segments. In addition, we discuss other aspect of otd, six3 and pax6 expression that are relevant to our understanding of evolutionary changes in morphology and function in arthropods.
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Affiliation(s)
- Bo Joakim Eriksson
- Department of Neurobiology, University of Vienna, Althanstrasse 14, 1090, Wien, Austria.
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31
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Streit A, Tambalo M, Chen J, Grocott T, Anwar M, Sosinsky A, Stern CD. Experimental approaches for gene regulatory network construction: the chick as a model system. Genesis 2012; 51:296-310. [PMID: 23174848 DOI: 10.1002/dvg.22359] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 11/09/2012] [Accepted: 11/11/2012] [Indexed: 01/23/2023]
Abstract
Setting up the body plan during embryonic development requires the coordinated action of many signals and transcriptional regulators in a precise temporal sequence and spatial pattern. The last decades have seen an explosion of information describing the molecular control of many developmental processes. The next challenge is to integrate this information into logic "wiring diagrams" that visualize gene actions and outputs, have predictive power and point to key control nodes. Here, we provide an experimental workflow on how to construct gene regulatory networks using the chick as model system.
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Affiliation(s)
- Andrea Streit
- Department of Craniofacial Development and Stem Cell Biology, King's College London, London, United Kingdom.
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32
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Henze MJ, Dannenhauer K, Kohler M, Labhart T, Gesemann M. Opsin evolution and expression in arthropod compound eyes and ocelli: insights from the cricket Gryllus bimaculatus. BMC Evol Biol 2012; 12:163. [PMID: 22935102 PMCID: PMC3502269 DOI: 10.1186/1471-2148-12-163] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 08/24/2012] [Indexed: 11/28/2022] Open
Abstract
Background Opsins are key proteins in animal photoreception. Together with a light-sensitive group, the chromophore, they form visual pigments which initiate the visual transduction cascade when photoactivated. The spectral absorption properties of visual pigments are mainly determined by their opsins, and thus opsins are crucial for understanding the adaptations of animal eyes. Studies on the phylogeny and expression pattern of opsins have received considerable attention, but our knowledge about insect visual opsins is still limited. Up to now, researchers have focused on holometabolous insects, while general conclusions require sampling from a broader range of taxa. We have therefore investigated visual opsins in the ocelli and compound eyes of the two-spotted cricket Gryllus bimaculatus, a hemimetabolous insect. Results Phylogenetic analyses place all identified cricket sequences within the three main visual opsin clades of insects. We assign three of these opsins to visual pigments found in the compound eyes with peak absorbances in the green (515 nm), blue (445 nm) and UV (332 nm) spectral range. Their expression pattern divides the retina into distinct regions: (1) the polarization-sensitive dorsal rim area with blue- and UV-opsin, (2) a newly-discovered ventral band of ommatidia with blue- and green-opsin and (3) the remainder of the compound eye with UV- and green-opsin. In addition, we provide evidence for two ocellar photopigments with peak absorbances in the green (511 nm) and UV (350 nm) spectral range, and with opsins that differ from those expressed in the compound eyes. Conclusions Our data show that cricket eyes are spectrally more specialized than has previously been assumed, suggesting that similar adaptations in other insect species might have been overlooked. The arrangement of spectral receptor types within some ommatidia of the cricket compound eyes differs from the generally accepted pattern found in holometabolous insect taxa and awaits a functional explanation. From the opsin phylogeny, we conclude that gene duplications, which permitted differential opsin expression in insect ocelli and compound eyes, occurred independently in several insect lineages and are recent compared to the origin of the eyes themselves.
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Affiliation(s)
- Miriam J Henze
- Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden.
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Mishra M, Rentsch M, Knust E. Crumbs regulates polarity and prevents light-induced degeneration of the simple eyes of Drosophila, the ocelli. Eur J Cell Biol 2012; 91:706-16. [PMID: 22608020 DOI: 10.1016/j.ejcb.2012.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Revised: 03/27/2012] [Accepted: 03/27/2012] [Indexed: 11/27/2022] Open
Abstract
The evolutionary conserved transmembrane protein Crumbs (Crb) regulates morphogenesis of photoreceptor cells in the compound eye of Drosophila and prevents light-dependent retinal degeneration. Here we examine the role of Crb in the ocelli, the simple eyes of Drosophila. We show that Crb is expressed in ocellar photoreceptor cells, where it defines a stalk membrane apical to the adherens junctions, similar as in photoreceptor cells of the compound eyes. Loss of function of crb disrupts polarity of ocellar photoreceptor cells, and results in mislocalisation of adherens junction proteins. This phenotype is more severe than that observed in mutant photoreceptor cells of the compound eye, and resembles more that of embryonic epithelia lacking crb. Similar as in compound eyes, crb protects ocellar photoreceptors from light induced degeneration, a function that depends on the extracellular portion of the Crb protein. Our data demonstrate that the function of crb in photoreceptor development and homeostasis is conserved in compound eyes and ocelli and underscores the evolutionarily relationship between these visual sense organs of Drosophila. The data will be discussed with respect to the difference in apico-basal organisation of these two cell types.
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Affiliation(s)
- Monalisa Mishra
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstr. 108, D-01307 Dresden, Germany
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34
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Duffy DJ. Instructive reconstruction: a new role for apoptosis in pattern formation. Instructive apoptotic patterning establishes de novo tissue generation via the apoptosis linked production of morphogenic signals. Bioessays 2012; 34:561-4. [PMID: 22488101 DOI: 10.1002/bies.201200018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Apoptosis is not only involved in patterning by removal of tissue (destructive apoptotic patterning), but it can also function in signalling the site of de novo tissue generation via morphogenic signals (instructive apoptotic patterning).
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Affiliation(s)
- David J Duffy
- Systems Biology Ireland, Conway Institute, University College Dublin, Belfield, Dublin, Ireland.
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Takagi A, Kurita K, Terasawa T, Nakamura T, Bando T, Moriyama Y, Mito T, Noji S, Ohuchi H. Functional analysis of the role of eyes absent and sine oculis in the developing eye of the cricket Gryllus bimaculatus. Dev Growth Differ 2012; 54:227-40. [PMID: 22348272 DOI: 10.1111/j.1440-169x.2011.01325.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In the cricket Gryllus bimaculatus, a hemimetabolous insect, the compound eyes begin to form in the embryo and increase 5-6 fold in size during the postembryonic development of the nymphal stage. Retinal stem cells in the anteroventral proliferation zone (AVPZ) of the nymphal eye proliferate to increase retinal progenitors, which then differentiate to form new ommatidia in the anterior region of the eye. However, mechanisms underlying this type of eye formation have not been well elucidated yet. Here, we found that the homologues of the retinal determination transcription factor genes of eyes absent (eya) and sine oculis (so) are expressed during the cricket embryonic eye formation. eya is also expressed intensely in the AVPZ of the nymphal eye. To explore their functions, we performed knockdown by RNA interference (RNAi). Knockdown of Gb'eya resulted in loss of the embryonic eye. In the nymphal eye, RNAi against Gb'eya or Gb'so impaired retinal morphology by apparently transforming cornea structures into head cuticle. These results imply that Gb'eya and Gb'so are essential for the differentiation of the retinal progenitor cells and maintaining retinal structures during eye development.
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Affiliation(s)
- Akira Takagi
- Department of Life Systems, Institute of Technology and Science, University of Tokushima, 2-1 Minami-Jyosanjima-cho, Tokushima City 770-8506, Japan
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36
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Chen Q, Li T, Hua B. Ultrastructure of the larval eye of the scorpionfly Panorpa dubia (mecoptera: Panorpidae) with implications for the evolutionary origin of holometabolous larvae. J Morphol 2012; 273:561-71. [DOI: 10.1002/jmor.20001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 10/01/2011] [Accepted: 10/31/2011] [Indexed: 11/08/2022]
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37
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Dong Z, Yuwen Y, Wang Q, Chen G, Liu D. Eight genes expression patterns during visual system regeneration in Dugesia japonica. Gene Expr Patterns 2012; 12:1-6. [DOI: 10.1016/j.gep.2011.08.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 06/28/2011] [Accepted: 08/01/2011] [Indexed: 11/29/2022]
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Tsachaki M, Sprecher SG. Genetic and developmental mechanisms underlying the formation of theDrosophilacompound eye. Dev Dyn 2011; 241:40-56. [DOI: 10.1002/dvdy.22738] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2011] [Indexed: 01/15/2023] Open
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Peter IS, Davidson EH. Evolution of gene regulatory networks controlling body plan development. Cell 2011; 144:970-85. [PMID: 21414487 DOI: 10.1016/j.cell.2011.02.017] [Citation(s) in RCA: 245] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2010] [Revised: 12/16/2010] [Accepted: 02/10/2011] [Indexed: 11/29/2022]
Abstract
Evolutionary change in animal morphology results from alteration of the functional organization of the gene regulatory networks (GRNs) that control development of the body plan. A major mechanism of evolutionary change in GRN structure is alteration of cis-regulatory modules that determine regulatory gene expression. Here we consider the causes and consequences of GRN evolution. Although some GRN subcircuits are of great antiquity, other aspects are highly flexible and thus in any given genome more recent. This mosaic view of the evolution of GRN structure explains major aspects of evolutionary process, such as hierarchical phylogeny and discontinuities of paleontological change.
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Affiliation(s)
- Isabelle S Peter
- Division of Biology 156-29, California Institute of Technology, Pasadena, CA 91125, USA.
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40
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Brockmann A, Domínguez-Cejudo MA, Amore G, Casares F. Regulation of ocellar specification and size by twin of eyeless and homothorax. Dev Dyn 2011; 240:75-85. [PMID: 21104743 DOI: 10.1002/dvdy.22494] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The retinal determination gene network (RDGN) constitutes a paradigm of a gene network controlling organ specification and growth. In this study, we probed the RDGN in the Drosophila ocelli, a set of simple eyes located on the fly's dorsal head, by studying the expression, regulation, and function of toy, hth, eya, and so, members of the Pax6, Meis, Eya, and Six gene families. Our results highlight the role of the pax6 gene toy, together with the hh signaling pathway, in the initiation of eya and so expression; the engagement of eya and so in a feedback loop necessary for their full expression; and the interplay between hh signaling and hth as a mechanism of organ size control, as general regulatory steps in the specification of visual organs.
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Affiliation(s)
- Anette Brockmann
- Centro Andaluz de Biología del Desarrollo (CABD), CSIC-UPO, Seville, Spain
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41
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Steinmetz PR, Urbach R, Posnien N, Eriksson J, Kostyuchenko RP, Brena C, Guy K, Akam M, Bucher G, Arendt D. Six3 demarcates the anterior-most developing brain region in bilaterian animals. EvoDevo 2010; 1:14. [PMID: 21190549 PMCID: PMC3025827 DOI: 10.1186/2041-9139-1-14] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 12/29/2010] [Indexed: 12/30/2023] Open
Abstract
Background The heads of annelids (earthworms, polychaetes, and others) and arthropods (insects, myriapods, spiders, and others) and the arthropod-related onychophorans (velvet worms) show similar brain architecture and for this reason have long been considered homologous. However, this view is challenged by the 'new phylogeny' placing arthropods and annelids into distinct superphyla, Ecdysozoa and Lophotrochozoa, together with many other phyla lacking elaborate heads or brains. To compare the organisation of annelid and arthropod heads and brains at the molecular level, we investigated head regionalisation genes in various groups. Regionalisation genes subdivide developing animals into molecular regions and can be used to align head regions between remote animal phyla. Results We find that in the marine annelid Platynereis dumerilii, expression of the homeobox gene six3 defines the apical region of the larval body, peripherally overlapping the equatorial otx+ expression. The six3+ and otx+ regions thus define the developing head in anterior-to-posterior sequence. In another annelid, the earthworm Pristina, as well as in the onychophoran Euperipatoides, the centipede Strigamia and the insects Tribolium and Drosophila, a six3/optix+ region likewise demarcates the tip of the developing animal, followed by a more posterior otx/otd+ region. Identification of six3+ head neuroectoderm in Drosophila reveals that this region gives rise to median neurosecretory brain parts, as is also the case in annelids. In insects, onychophorans and Platynereis, the otx+ region instead harbours the eye anlagen, which thus occupy a more posterior position. Conclusions These observations indicate that the annelid, onychophoran and arthropod head develops from a conserved anterior-posterior sequence of six3+ and otx+ regions. The six3+ anterior pole of the arthropod head and brain accordingly lies in an anterior-median embryonic region and, in consequence, the optic lobes do not represent the tip of the neuraxis. These results support the hypothesis that the last common ancestor of annelids and arthropods already possessed neurosecretory centres in the most anterior region of the brain. In light of its broad evolutionary conservation in protostomes and, as previously shown, in deuterostomes, the six3-otx head patterning system may be universal to bilaterian animals.
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Affiliation(s)
- Patrick Rh Steinmetz
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69012 Heidelberg, Germany.,University of Vienna, Department for Molecular Evolution and Development, Althanstrasse 14, A-1090 Vienna, Austria
| | - Rolf Urbach
- Johannes Gutenberg-Universität Mainz, Institut für Genetik, J.-J.-Becher-Weg 32, 55128 Mainz, Germany
| | - Nico Posnien
- Johann-Friedrich-Blumenbach-Institute of Zoology, Anthropology and Developmental Biology, DFG Research Centre for Molecular Physiology of the Brain (CMPB), Georg August University, von-Liebig-Weg-11, 37077 Göttingen, Germany.,Vetmeduni Vienna, Institute of Population Genetics, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Joakim Eriksson
- University Museum of Zoology, Department of Zoology, Downing Street, Cambridge CB2 3EJ, UK.,Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, UK
| | - Roman P Kostyuchenko
- Department of Embryology, State University of St. Petersburg, Universitetskaya nab. 7/9, 199034 St. Petersburg, Russia
| | - Carlo Brena
- University Museum of Zoology, Department of Zoology, Downing Street, Cambridge CB2 3EJ, UK
| | - Keren Guy
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69012 Heidelberg, Germany
| | - Michael Akam
- University Museum of Zoology, Department of Zoology, Downing Street, Cambridge CB2 3EJ, UK
| | - Gregor Bucher
- Johann-Friedrich-Blumenbach-Institute of Zoology, Anthropology and Developmental Biology, DFG Research Centre for Molecular Physiology of the Brain (CMPB), Georg August University, von-Liebig-Weg-11, 37077 Göttingen, Germany
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69012 Heidelberg, Germany
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Lynch VJ, Wagner GP. Revisiting a classic example of transcription factor functional equivalence: are Eyeless and Pax6 functionally equivalent or divergent? JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2010; 316B:93-8. [DOI: 10.1002/jez.b.21373] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 08/04/2010] [Accepted: 08/06/2010] [Indexed: 11/07/2022]
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Birge LM, Pitts ML, Richard BH, Wilkinson GS. Length polymorphism and head shape association among genes with polyglutamine repeats in the stalk-eyed fly, Teleopsis dalmanni. BMC Evol Biol 2010; 10:227. [PMID: 20663190 PMCID: PMC3055267 DOI: 10.1186/1471-2148-10-227] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 07/27/2010] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Polymorphisms of single amino acid repeats (SARPs) are a potential source of genetic variation for rapidly evolving morphological traits. Here, we characterize variation in and test for an association between SARPs and head shape, a trait under strong sexual selection, in the stalk-eyed fly, Teleopsis dalmanni. Using an annotated expressed sequence tag database developed from eye-antennal imaginal disc tissues in T. dalmanni we identified 98 genes containing nine or more consecutive copies of a single amino acid. We then quantify variation in length and allelic diversity for 32 codon and 15 noncodon repeat regions in a large outbred population. We also assessed the frequency with which amino acid repeats are either gained or lost by identifying sequence similarities between T. dalmanni SARP loci and their orthologs in Drosophila melanogaster. Finally, to identify SARP containing genes that may influence head development we conducted a two-generation association study after assortatively mating for extreme relative eyespan. RESULTS We found that glutamine repeats occur more often than expected by amino acid abundance among 3,400 head development genes in T. dalmanni and D. melanogaster. Furthermore, glutamine repeats occur disproportionately in transcription factors. Loci with glutamine repeats exhibit heterozygosities and allelic diversities that do not differ from noncoding dinucleotide microsatellites, including greater variation among X-linked than autosomal regions. In the majority of cases, repeat tracts did not overlap between T. dalmanni and D. melanogaster indicating that large glutamine repeats are gained or lost frequently during Dipteran evolution. Analysis of covariance reveals a significant effect of parental genotype on mean progeny eyespan, with body length as a covariate, at six SARP loci [CG33692, ptip, band4.1 inhibitor LRP interactor, corto, 3531953:1, and ecdysone-induced protein 75B (Eip75B)]. Mixed model analysis of covariance using the eyespan of siblings segregating for repeat length variation confirms that significant genotype-phenotype associations exist for at least one sex at five of these loci and for one gene, CG33692, longer repeats were associated with longer relative eyespan in both sexes. CONCLUSION Among genes expressed during head development in stalk-eyed flies, long codon repeats typically contain glutamine, occur in transcription factors and exhibit high levels of heterozygosity. Furthermore, the presence of significant associations within families between repeat length and head shape indicates that six genes, or genes linked to them, contribute genetic variation to the development of this extremely sexually dimorphic trait.
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Affiliation(s)
- Leanna M Birge
- Department of Biology, University of Maryland, College Park, MD 20742 USA
- University College London, Research Department of Genetics, Evolution and Environment, Wolfson House, 4 Stephenson Way, London, NW1 2HE, UK
| | - Marie L Pitts
- Department of Biology, The College of William and Mary, Williamsburg, VA 23187 USA
| | - Baker H Richard
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, NY, 10024 USA
| | - Gerald S Wilkinson
- Department of Biology, University of Maryland, College Park, MD 20742 USA
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Dong Y, Friedrich M. Enforcing biphasic eye development in a directly developing insect by transient knockdown of single eye selector genes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2010; 314:104-14. [PMID: 19637278 DOI: 10.1002/jez.b.21313] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The visual system of indirectly developing insects such as Drosophila passes through two phases of development. Larval eyes form in the embryo, whereas the adult compound eyes form during metamorphosis. Comparative evidence implies that this biphasic mode of visual system development evolved from the continuously developing eye of directly developing insects. We investigated the developmental basis of this evolutionary transformation in a directly developing insect taking advantage of the time-limited nature of systemic RNAi in the grasshopper Schistocerca americana. Transient knockdown of the homologs of the early retinal genes eyes absent (eya) or sine oculis (so) both induced long-term arrest of eye development in grasshopper nymphs. Eye development, however, resumed after knockdown expiry. This finding sheds first light on the molecular regulation of postembryonic eye development in directly developing insects and unravels an inherent capacity of the underlying gene regulatory network to accommodate for partitioning visual system development into discrete phases, as in indirectly developing insects.
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Affiliation(s)
- Ying Dong
- Harold C. Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Rivera AS, Pankey MS, Plachetzki DC, Villacorta C, Syme AE, Serb JM, Omilian AR, Oakley TH. Gene duplication and the origins of morphological complexity in pancrustacean eyes, a genomic approach. BMC Evol Biol 2010; 10:123. [PMID: 20433736 PMCID: PMC2888819 DOI: 10.1186/1471-2148-10-123] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2009] [Accepted: 04/30/2010] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Duplication and divergence of genes and genetic networks is hypothesized to be a major driver of the evolution of complexity and novel features. Here, we examine the history of genes and genetic networks in the context of eye evolution by using new approaches to understand patterns of gene duplication during the evolution of metazoan genomes. We hypothesize that 1) genes involved in eye development and phototransduction have duplicated and are retained at higher rates in animal clades that possess more distinct types of optical design; and 2) genes with functional relationships were duplicated and lost together, thereby preserving genetic networks. To test these hypotheses, we examine the rates and patterns of gene duplication and loss evident in 19 metazoan genomes, including that of Daphnia pulex - the first completely sequenced crustacean genome. This is of particular interest because the pancrustaceans (hexapods+crustaceans) have more optical designs than any other major clade of animals, allowing us to test specifically whether the high amount of disparity in pancrustacean eyes is correlated with a higher rate of duplication and retention of vision genes. RESULTS Using protein predictions from 19 metazoan whole-genome projects, we found all members of 23 gene families known to be involved in eye development or phototransduction and deduced their phylogenetic relationships. This allowed us to estimate the number and timing of gene duplication and loss events in these gene families during animal evolution. When comparing duplication/retention rates of these genes, we found that the rate was significantly higher in pancrustaceans than in either vertebrates or non-pancrustacean protostomes. Comparing patterns of co-duplication across Metazoa showed that while these eye-genes co-duplicate at a significantly higher rate than those within a randomly shuffled matrix, many genes with known functional relationships in model organisms did not co-duplicate more often than expected by chance. CONCLUSIONS Overall, and when accounting for factors such as differential rates of whole-genome duplication in different groups, our results are broadly consistent with the hypothesis that genes involved in eye development and phototransduction duplicate at a higher rate in Pancrustacea, the group with the greatest variety of optical designs. The result that these genes have a significantly high number of co-duplications and co-losses could be influenced by shared functions or other unstudied factors such as synteny. Since we did not observe co-duplication/co-loss of genes for all known functional modules (e.g. specific regulatory networks), the interactions among suites of known co-functioning genes (modules) may be plastic at the temporal scale of analysis performed here. Other factors in addition to gene duplication - such as cis-regulation, heterotopy, and co-option - are also likely to be strong factors in the diversification of eye types.
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Schlosser G. Making senses development of vertebrate cranial placodes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 283:129-234. [PMID: 20801420 DOI: 10.1016/s1937-6448(10)83004-7] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cranial placodes (which include the adenohypophyseal, olfactory, lens, otic, lateral line, profundal/trigeminal, and epibranchial placodes) give rise to many sense organs and ganglia of the vertebrate head. Recent evidence suggests that all cranial placodes may be developmentally related structures, which originate from a common panplacodal primordium at neural plate stages and use similar regulatory mechanisms to control developmental processes shared between different placodes such as neurogenesis and morphogenetic movements. After providing a brief overview of placodal diversity, the present review summarizes current evidence for the existence of a panplacodal primordium and discusses the central role of transcription factors Six1 and Eya1 in the regulation of processes shared between different placodes. Upstream signaling events and transcription factors involved in early embryonic induction and specification of the panplacodal primordium are discussed next. I then review how individual placodes arise from the panplacodal primordium and present a model of multistep placode induction. Finally, I briefly summarize recent advances concerning how placodal neurons and sensory cells are specified, and how morphogenesis of placodes (including delamination and migration of placode-derived cells and invagination) is controlled.
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Affiliation(s)
- Gerhard Schlosser
- Zoology, School of Natural Sciences & Martin Ryan Institute, National University of Ireland, Galway, Ireland
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Vopalensky P, Kozmik Z. Eye evolution: common use and independent recruitment of genetic components. Philos Trans R Soc Lond B Biol Sci 2009; 364:2819-32. [PMID: 19720647 DOI: 10.1098/rstb.2009.0079] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Animal eyes can vary in complexity ranging from a single photoreceptor cell shaded by a pigment cell to elaborate arrays of these basic units, which allow image formation in compound eyes of insects or camera-type eyes of vertebrates. The evolution of the eye requires involvement of several distinct components-photoreceptors, screening pigment and genes orchestrating their proper temporal and spatial organization. Analysis of particular genetic and biochemical components shows that many evolutionary processes have participated in eye evolution. Multiple examples of co-option of crystallins, Galpha protein subunits and screening pigments contrast with the conserved role of opsins and a set of transcription factors governing eye development in distantly related animal phyla. The direct regulation of essential photoreceptor genes by these factors suggests that this regulatory relationship might have been already established in the ancestral photoreceptor cell.
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Affiliation(s)
- Pavel Vopalensky
- Department of Transcriptional Regulation, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, Prague 4 CZ 14220, Czech Republic
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Melzer RR. Persisting stemma neuropils inChaoborus crystallinus(Diptera: Chaoboridae): Development and evolution of a bipartite visual system. J Morphol 2009; 270:1524-30. [DOI: 10.1002/jmor.10779] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Wang LH, Huang YT, Tsai YC, Sun YH. The role of eyg Pax gene in the development of the head vertex in Drosophila. Dev Biol 2009; 337:246-58. [PMID: 19896935 DOI: 10.1016/j.ydbio.2009.10.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 09/17/2009] [Accepted: 10/27/2009] [Indexed: 11/16/2022]
Abstract
The Drosophila head vertex is composed of three ocelli, stereotypic bristle patterns and characteristic cuticles. It is derived from the fusion of two eye-antenna discs. The head vertex primordium is located at the anterior-dorsal region of the eye disc. The orthodenticle (otd) homeobox gene is expressed in the primordium and is functionally required for its development and patterning. Here we show that the Pax gene eye gone (eyg) is expressed adjacent to the otd expression domain in the eye disc. otd is required and sufficient to repress eyg transcription, thereby preventing eyg from expressing in the head vertex primordium. In otd mutant, eyg expression is derepressed in the head vertex primordium and is a major negative effector to block head vertex development. Therefore, otd not only needs to induce downstream effector genes to execute the development and patterning of the head vertex development, but also needs to actively repress the negative regulator eyg. In addition, eyg is required for the development of the lateral bristles in the head vertex. So eyg plays both positive and negative roles in head vertex development.
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Affiliation(s)
- Lan-Hsin Wang
- Graduate Institute of Life Sciences, National Defense Medical Center, Neihu, Taipei, Taiwan, Republic of China
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Yang X, ZarinKamar N, Bao R, Friedrich M. Probing the Drosophila retinal determination gene network in Tribolium (I): The early retinal genes dachshund, eyes absent and sine oculis. Dev Biol 2009; 333:202-14. [DOI: 10.1016/j.ydbio.2009.02.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 02/18/2009] [Accepted: 02/19/2009] [Indexed: 12/24/2022]
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