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Klingler M, Bucher G. The red flour beetle T. castaneum: elaborate genetic toolkit and unbiased large scale RNAi screening to study insect biology and evolution. EvoDevo 2022; 13:14. [PMID: 35854352 PMCID: PMC9295526 DOI: 10.1186/s13227-022-00201-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022] Open
Abstract
The red flour beetle Tribolium castaneum has emerged as an important insect model system for a variety of topics. With respect to studying gene function, it is second only to the vinegar fly D. melanogaster. The RNAi response in T. castaneum is exceptionally strong and systemic, and it appears to target all cell types and processes. Uniquely for emerging model organisms, T. castaneum offers the opportunity of performing time- and cost-efficient large-scale RNAi screening, based on commercially available dsRNAs targeting all genes, which are simply injected into the body cavity. Well established transgenic and genome editing approaches are met by ease of husbandry and a relatively short generation time. Consequently, a number of transgenic tools like UAS/Gal4, Cre/Lox, imaging lines and enhancer trap lines are already available. T. castaneum has been a genetic experimental system for decades and now has become a workhorse for molecular and reverse genetics as well as in vivo imaging. Many aspects of development and general biology are more insect-typical in this beetle compared to D. melanogaster. Thus, studying beetle orthologs of well-described fly genes has allowed macro-evolutionary comparisons in developmental processes such as axis formation, body segmentation, and appendage, head and brain development. Transgenic approaches have opened new ways for in vivo imaging. Moreover, this emerging model system is the first choice for research on processes that are not represented in the fly, or are difficult to study there, e.g. extraembryonic tissues, cryptonephridial organs, stink gland function, or dsRNA-based pesticides.
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Affiliation(s)
- Martin Klingler
- Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 5, 91058, Erlangen, Germany.
| | - Gregor Bucher
- Johann-Friedrich-Blumenbach-Institut, GZMB, University of Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany.
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2
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Diaz-Cuadros M, Pourquié O, El-Sherif E. Patterning with clocks and genetic cascades: Segmentation and regionalization of vertebrate versus insect body plans. PLoS Genet 2021; 17:e1009812. [PMID: 34648490 PMCID: PMC8516289 DOI: 10.1371/journal.pgen.1009812] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Oscillatory and sequential processes have been implicated in the spatial patterning of many embryonic tissues. For example, molecular clocks delimit segmental boundaries in vertebrates and insects and mediate lateral root formation in plants, whereas sequential gene activities are involved in the specification of regional identities of insect neuroblasts, vertebrate neural tube, vertebrate limb, and insect and vertebrate body axes. These processes take place in various tissues and organisms, and, hence, raise the question of what common themes and strategies they share. In this article, we review 2 processes that rely on the spatial regulation of periodic and sequential gene activities: segmentation and regionalization of the anterior-posterior (AP) axis of animal body plans. We study these processes in species that belong to 2 different phyla: vertebrates and insects. By contrasting 2 different processes (segmentation and regionalization) in species that belong to 2 distantly related phyla (arthropods and vertebrates), we elucidate the deep logic of patterning by oscillatory and sequential gene activities. Furthermore, in some of these organisms (e.g., the fruit fly Drosophila), a mode of AP patterning has evolved that seems not to overtly rely on oscillations or sequential gene activities, providing an opportunity to study the evolution of pattern formation mechanisms.
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Affiliation(s)
- Margarete Diaz-Cuadros
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
| | - Olivier Pourquié
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Pathology, Brigham and Women’s Hospital, Boston, Massachusetts, United States of America
- Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts, United States of America
| | - Ezzat El-Sherif
- Division of Developmental Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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3
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Chipman AD. The evolution of the gene regulatory networks patterning the Drosophila Blastoderm. Curr Top Dev Biol 2021; 139:297-324. [PMID: 32450964 DOI: 10.1016/bs.ctdb.2020.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Drosophila blastoderm gene regulatory network is one of the best studied networks in biology. It is composed of a series of tiered sub-networks that act sequentially to generate a primary segmental pattern. Many of these sub-networks have been studied in other arthropods, allowing us to reconstruct how each of them evolved over the transition from the arthropod ancestor to the situation seen in Drosophila today. I trace the evolution of each of these networks, showing how some of them have been modified significantly in Drosophila relative to the ancestral state while others are largely conserved across evolutionary timescales. I compare the putative ancestral arthropod segmentation network with that found in Drosophila and discuss how and why it has been modified throughout evolution, and to what extent this modification is unusual.
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Affiliation(s)
- Ariel D Chipman
- The Department of Ecology, Evolution & Behavior, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel.
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4
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Novikova AV, Auman T, Cohen M, Oleynik O, Stahi-Hitin R, Gil E, Weisbrod A, Chipman AD. The multiple roles of caudal in early development of the milkweed bug Oncopeltus fasciatus. Dev Biol 2020; 467:66-76. [PMID: 32891622 DOI: 10.1016/j.ydbio.2020.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 11/27/2022]
Abstract
The homeobox transcription factor Caudal has conserved roles in all Bilateria in defining the posterior pole and in controlling posterior elongation. These roles are seemingly similar and are difficult to disentangle. We have carried out a detailed analysis of the expression, function and interactions of the caudal ortholog of the milkweed bug, Oncopeltus fasciatus, a hemimetabolous insect with a conservative early development process, in order to understand its different functions throughout development. In Oncopeltus, caudal is not maternally deposited, but has a sequence of roles in the posterior of the embryos throughout early development. It defines and maintains a posterior-anterior gradient in the blastoderm and modulates the activity of segmentation genes in simultaneous segmentation during the blastoderm stage. It later defines the invagination site and the posterior segment addition zone (SAZ) in the germband. It maintains the posterior SAZ cells in an undifferentiated proliferative state, while promoting dynamic expression of segmentation genes in the anterior SAZ. We show that rather than being a simple posterior determinant, Caudal is involved in several distinct regulatory networks, each with a distinct developmental role.
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Affiliation(s)
- Asya V Novikova
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Tzach Auman
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Mira Cohen
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Olesya Oleynik
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Reut Stahi-Hitin
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Ella Gil
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Anat Weisbrod
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Ariel D Chipman
- The Department of Ecology, Evolution & Behavior, Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.
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5
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Gurska D, Vargas Jentzsch IM, Panfilio KA. Unexpected mutual regulation underlies paralogue functional diversification and promotes epithelial tissue maturation in Tribolium. Commun Biol 2020; 3:552. [PMID: 33020571 PMCID: PMC7536231 DOI: 10.1038/s42003-020-01250-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 08/21/2020] [Indexed: 02/03/2023] Open
Abstract
Insect Hox3/zen genes represent an evolutionary hotspot for changes in function and copy number. Single orthologues are required either for early specification or late morphogenesis of the extraembryonic tissues, which protect the embryo. The tandemly duplicated zen paralogues of the beetle Tribolium castaneum present a unique opportunity to investigate both functions in a single species. We dissect the paralogues' expression dynamics (transcript and protein) and transcriptional targets (RNA-seq after RNAi) throughout embryogenesis. We identify an unexpected role of Tc-Zen2 in repression of Tc-zen1, generating a negative feedback loop that promotes developmental progression. Tc-Zen2 regulation is dynamic, including within co-expressed multigene loci. We also show that extraembryonic development is the major event within the transcriptional landscape of late embryogenesis and provide a global molecular characterization of the extraembryonic serosal tissue. Altogether, we propose that paralogue mutual regulation arose through multiple instances of zen subfunctionalization, leading to their complementary extant roles.
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Affiliation(s)
- Daniela Gurska
- Institute of Zoology: Developmental Biology, University of Cologne, 50674, Cologne, Germany
| | - Iris M Vargas Jentzsch
- Institute of Zoology: Developmental Biology, University of Cologne, 50674, Cologne, Germany
| | - Kristen A Panfilio
- Institute of Zoology: Developmental Biology, University of Cologne, 50674, Cologne, Germany.
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
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6
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Constantinou SJ, Duan N, Nagy LM, Chipman AD, Williams TA. Elongation during segmentation shows axial variability, low mitotic rates, and synchronized cell cycle domains in the crustacean, Thamnocephalus platyurus. EvoDevo 2020; 11:1. [PMID: 31988708 PMCID: PMC6969478 DOI: 10.1186/s13227-020-0147-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Accepted: 01/03/2020] [Indexed: 12/20/2022] Open
Abstract
Background Segmentation in arthropods typically occurs by sequential addition of segments from a posterior growth zone. However, the amount of tissue required for growth and the cell behaviors producing posterior elongation are sparsely documented. Results Using precisely staged larvae of the crustacean, Thamnocephalus platyurus, we systematically examine cell division patterns and morphometric changes associated with posterior elongation during segmentation. We show that cell division occurs during normal elongation but that cells in the growth zone need only divide ~ 1.5 times to meet growth estimates; correspondingly, direct measures of cell division in the growth zone are low. Morphometric measurements of the growth zone and of newly formed segments suggest tagma-specific features of segment generation. Using methods for detecting two different phases in the cell cycle, we show distinct domains of synchronized cells in the posterior trunk. Borders of cell cycle domains correlate with domains of segmental gene expression, suggesting an intimate link between segment generation and cell cycle regulation. Conclusions Emerging measures of cellular dynamics underlying posterior elongation already show a number of intriguing characteristics that may be widespread among sequentially segmenting arthropods and are likely a source of evolutionary variability. These characteristics include: the low rates of posterior mitosis, the apparently tight regulation of cell cycle at the growth zone/new segment border, and a correlation between changes in elongation and tagma boundaries.
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Affiliation(s)
- Savvas J Constantinou
- 1Biology Department, Trinity College, Hartford, CT USA.,4Present Address: Department of Integrative Biology, Michigan State University, East Lansing, MI 48824 USA
| | - Nicole Duan
- 1Biology Department, Trinity College, Hartford, CT USA.,5Present Address: Bioinformatics and Quantitative Biosciences, Georgia Institute of Technology, North Avenue, Atlanta, GA 30332 USA
| | - Lisa M Nagy
- 2Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ 85721 USA
| | - Ariel D Chipman
- 3The Department of Ecology, Evolution and Behavior, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 91904 Jerusalem, Israel
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7
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Benton MA, Frey N, Nunes da Fonseca R, von Levetzow C, Stappert D, Hakeemi MS, Conrads KH, Pechmann M, Panfilio KA, Lynch JA, Roth S. Fog signaling has diverse roles in epithelial morphogenesis in insects. eLife 2019; 8:47346. [PMID: 31573513 PMCID: PMC6794076 DOI: 10.7554/elife.47346] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 09/30/2019] [Indexed: 12/14/2022] Open
Abstract
The Drosophila Fog pathway represents one of the best-understood signaling cascades controlling epithelial morphogenesis. During gastrulation, Fog induces apical cell constrictions that drive the invagination of mesoderm and posterior gut primordia. The cellular mechanisms underlying primordia internalization vary greatly among insects and recent work has suggested that Fog signaling is specific to the fast mode of gastrulation found in some flies. On the contrary, here we show in the beetle Tribolium, whose development is broadly representative for insects, that Fog has multiple morphogenetic functions. It modulates mesoderm internalization and controls a massive posterior infolding involved in gut and extraembryonic development. In addition, Fog signaling affects blastoderm cellularization, primordial germ cell positioning, and cuboidal-to-squamous cell shape transitions in the extraembryonic serosa. Comparative analyses with two other distantly related insect species reveals that Fog's role during cellularization is widely conserved and therefore might represent the ancestral function of the pathway.
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Affiliation(s)
- Matthew Alan Benton
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany.,Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Nadine Frey
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
| | | | - Cornelia von Levetzow
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
| | - Dominik Stappert
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
| | - Muhammad Salim Hakeemi
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
| | - Kai H Conrads
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
| | - Matthias Pechmann
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
| | - Kristen A Panfilio
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany.,School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Jeremy A Lynch
- Department of Biological Sciences, University of Illinois, Chicago, United States
| | - Siegfried Roth
- Institute for Zoology/Developmental Biology, Biocenter, University of Cologne, Köln, Germany
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8
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Linz DM, Hu Y, Moczek AP. The origins of novelty from within the confines of homology: the developmental evolution of the digging tibia of dung beetles. Proc Biol Sci 2019; 286:20182427. [PMID: 30963933 PMCID: PMC6408602 DOI: 10.1098/rspb.2018.2427] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/23/2019] [Indexed: 11/12/2022] Open
Abstract
Understanding the origin of novel complex traits is among the most fundamental goals in evolutionary biology. The most widely used definition of novelty in evolution assumes the absence of homology, yet where homology ends and novelty begins is increasingly difficult to parse as evo devo continuously revises our understanding of what constitutes homology. Here, we executed a case study to explore the earliest stages of innovation by examining the tibial teeth of tunnelling dung beetles. Tibial teeth are a morphologically modest innovation, composed of relatively simple body wall projections and contained fully within the fore tibia, a leg segment whose own homology status is unambiguous. We first demonstrate that tibial teeth aid in multiple digging behaviours. We then show that the developmental evolution of tibial teeth was dominated by the redeployment of locally pre-existing gene networks. At the same time, we find that even at this very early stage of innovation, at least two genes that ancestrally function in embryonic patterning and thus entirely outside the spatial and temporal context of leg formation, have already become recruited to help shape the formation of tibial teeth. Our results suggest a testable model for how developmental evolution scaffolds innovation.
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9
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Liu Q, Onal P, Datta RR, Rogers JM, Schmidt-Ott U, Bulyk ML, Small S, Thornton JW. Ancient mechanisms for the evolution of the bicoid homeodomain's function in fly development. eLife 2018; 7:e34594. [PMID: 30298815 PMCID: PMC6177261 DOI: 10.7554/elife.34594] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 07/28/2018] [Indexed: 12/14/2022] Open
Abstract
The ancient mechanisms that caused developmental gene regulatory networks to diversify among distantly related taxa are not well understood. Here we use ancestral protein reconstruction, biochemical experiments, and developmental assays of transgenic animals carrying reconstructed ancestral genes to investigate how the transcription factor Bicoid (Bcd) evolved its central role in anterior-posterior patterning in flies. We show that most of Bcd's derived functions are attributable to evolutionary changes within its homeodomain (HD) during a phylogenetic interval >140 million years ago. A single substitution from this period (Q50K) accounts almost entirely for the evolution of Bcd's derived DNA specificity in vitro. In transgenic embryos expressing the reconstructed ancestral HD, however, Q50K confers activation of only a few of Bcd's transcriptional targets and yields a very partial rescue of anterior development. Adding a second historical substitution (M54R) confers regulation of additional Bcd targets and further rescues anterior development. These results indicate that two epistatically interacting mutations played a major role in the evolution of Bcd's controlling regulatory role in early development. They also show how ancestral sequence reconstruction can be combined with in vivo characterization of transgenic animals to illuminate the historical mechanisms of developmental evolution.
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Affiliation(s)
- Qinwen Liu
- Department of Ecology and EvolutionUniversity of ChicagoChicagoUnited States
| | - Pinar Onal
- Department of BiologyNew York UniversityNew YorkUnited States
| | - Rhea R Datta
- Department of BiologyNew York UniversityNew YorkUnited States
| | - Julia M Rogers
- Committee on Higher Degrees in BiophysicsHarvard UniversityCambridgeUnited States
- Division of Genetics, Department of MedicineBrigham and Women’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Urs Schmidt-Ott
- Department of Organismal Biology and AnatomyUniversity of ChicagoChicagoUnited States
| | - Martha L Bulyk
- Committee on Higher Degrees in BiophysicsHarvard UniversityCambridgeUnited States
- Division of Genetics, Department of MedicineBrigham and Women’s Hospital and Harvard Medical SchoolBostonUnited States
- Department of PathologyBrigham and Women’s Hospital and Harvard Medical SchoolBostonUnited States
| | - Stephen Small
- Department of BiologyNew York UniversityNew YorkUnited States
| | - Joseph W Thornton
- Department of Ecology and EvolutionUniversity of ChicagoChicagoUnited States
- Department of Human GeneticsUniversity of ChicagoChicagoUnited States
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10
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Double abdomen in a short-germ insect: Zygotic control of axis formation revealed in the beetle Tribolium castaneum. Proc Natl Acad Sci U S A 2018; 115:1819-1824. [PMID: 29432152 PMCID: PMC5828605 DOI: 10.1073/pnas.1716512115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
One of the first crucial steps of animal development is to distinguish the anterior versus the posterior pole of the embryo, i.e., the AP axis. If this process fails, embryos may develop two mirror image tails or heads. In the fly Drosophila, the mother provides the signals required for AP axis formation, while in vertebrates, gene activity of the embryo is required as well. We identified two genes whose knockdown leads to double-tail phenotypes in the beetle Tribolium, representing the insect-typical short-germ embryogenesis. Intriguingly, embryo polarity depends on zygotic gene activities and Wnt signaling. Hence, short-germ insect axis formation is more similar to vertebrates than the mechanism employed by Drosophila. The distinction of anterior versus posterior is a crucial first step in animal embryogenesis. In the fly Drosophila, this axis is established by morphogenetic gradients contributed by the mother that regulate zygotic target genes. This principle has been considered to hold true for insects in general but is fundamentally different from vertebrates, where zygotic genes and Wnt signaling are required. We investigated symmetry breaking in the beetle Tribolium castaneum, which among insects represents the more ancestral short-germ embryogenesis. We found that maternal Tc-germ cell-less is required for anterior localization of maternal Tc-axin, which represses Wnt signaling and promotes expression of anterior zygotic genes. Both RNAi targeting Tc-germ cell-less or double RNAi knocking down the zygotic genes Tc-homeobrain and Tc-zen1 led to the formation of a second growth zone at the anterior, which resulted in double-abdomen phenotypes. Conversely, interfering with two posterior factors, Tc-caudal and Wnt, caused double-anterior phenotypes. These findings reveal that maternal and zygotic mechanisms, including Wnt signaling, are required for establishing embryo polarity and induce the segmentation clock in a short-germ insect.
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11
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van der Meer JM. RNase reverses segment sequence in the anterior of a beetle egg (Callosobruchus maculatus, Coleoptera). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2018; 330:52-59. [PMID: 29393571 DOI: 10.1002/jez.b.22789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 11/30/2017] [Accepted: 01/09/2018] [Indexed: 11/07/2022]
Abstract
The genetic regulation of anterior-posterior segment pattern development has been elucidated in detail for Drosophila, but it is not canonical for insects. A surprising diversity of regulatory mechanisms is being uncovered not only between insect orders, but also within the order of the Diptera. The question is whether the same diversity of regulatory mechanisms exists within other insect orders. I show that anterior puncture of the egg of the pea beetle Callosobruchus maculatus submerged in RNase can induce double abdomen development suggesting a role for maternal mRNA. In a double abdomen, anterior segments are replaced by posterior segments oriented in mirror image symmetry to the original posterior segments. This effect is specific for RNase activity, for treatment of the anterior egg pole and for cytoplasmic RNA. Yield depends on developmental stage, enzyme concentration, and temperature. A maximum of 30% of treated eggs reversed segment sequence after submersion and puncture in 10 μg/mL RNase S reconstituted from S-protein and S-peptide at 30°C. This result sets the stage for an analysis of the genetic regulation of segment pattern formation in the long germ embryo of the coleopteran Callosobruchus and for comparison with the short germ embryo of the coleopteran Tribolium.
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Affiliation(s)
- Jitse M van der Meer
- Department of Zoology, Radboud University, Huygensgebouw, Heyendaalseweg, Nijmegen, The Netherlands.,Department of Zoology, University of Heidelberg, Im Neuenheimer Feld, Heidelberg, Germany.,Department of Biological Sciences, Purdue University, West Lafayette, Indiana, U.S.A.,Department of Biology, Redeemer University College, Hamilton, ON, Canada
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12
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Toll Genes Have an Ancestral Role in Axis Elongation. Curr Biol 2016; 26:1609-1615. [DOI: 10.1016/j.cub.2016.04.055] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/06/2016] [Accepted: 04/20/2016] [Indexed: 12/17/2022]
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13
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Carter JM, Gibbs M, Breuker CJ. Divergent RNA Localisation Patterns of Maternal Genes Regulating Embryonic Patterning in the Butterfly Pararge aegeria. PLoS One 2015; 10:e0144471. [PMID: 26633019 PMCID: PMC4669120 DOI: 10.1371/journal.pone.0144471] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/18/2015] [Indexed: 12/19/2022] Open
Abstract
The maternal effect genes responsible for patterning the embryo along the antero-posterior (AP) axis are broadly conserved in insects. The precise function of these maternal effect genes is the result of the localisation of their mRNA in the oocyte. The main developmental mechanisms involved have been elucidated in Drosophila melanogaster, but recent studies have shown that other insect orders often diverge in RNA localisation patterns. A recent study has shown that in the butterfly Pararge aegeria the distinction between blastodermal embryonic (i.e. germ band) and extra-embryonic tissue (i.e. serosa) is already specified in the oocyte during oogenesis in the ovariole, long before blastoderm cellularisation. To examine the extent by which a female butterfly specifies and patterns the AP axis within the region fated to be the germ band, and whether she specifies a germ plasm, we performed in situ hybridisation experiments on oocytes in P. aegeria ovarioles and on early embryos. RNA localisation of the following key maternal effect genes were investigated: caudal (cad), orthodenticle (otd), hunchback (hb) and four nanos (nos) paralogs, as well as TDRD7 a gene containing a key functional domain (OST-HTH/LOTUS) shared with oskar. TDRD7 was mainly confined to the follicle cells, whilst hb was exclusively zygotically transcribed. RNA of some of the nos paralogs, otd and cad revealed complex localisation patterns within the cortical region prefiguring the germ band (i.e. germ cortex). Rather interestingly, otd was localised within and outside the anterior of the germ cortex. Transcripts of nos-O formed a distinct granular ring in the middle of the germ cortex possibly prefiguring the region where germline stem cells form. These butterfly RNA localisation patterns are highly divergent with respect to other insects, highlighting the diverse ways in which different insect orders maternally regulate early embryogenesis of their offspring.
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Affiliation(s)
- Jean-Michel Carter
- Evolutionary Developmental Biology Research Group, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, OX3 0BP, United Kingdom
| | - Melanie Gibbs
- NERC Centre for Ecology & Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford, Oxfordshire, OX10 8BB, United Kingdom
| | - Casper J. Breuker
- Evolutionary Developmental Biology Research Group, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, OX3 0BP, United Kingdom
- * E-mail:
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14
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Notch signaling induces cell proliferation in the labrum in a regulatory network different from the thoracic legs. Dev Biol 2015; 408:164-77. [DOI: 10.1016/j.ydbio.2015.09.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 09/25/2015] [Accepted: 09/26/2015] [Indexed: 11/18/2022]
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15
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Abstract
Genetic screens are powerful tools to identify the genes required for a given biological process. However, for technical reasons, comprehensive screens have been restricted to very few model organisms. Therefore, although deep sequencing is revealing the genes of ever more insect species, the functional studies predominantly focus on candidate genes previously identified in Drosophila, which is biasing research towards conserved gene functions. RNAi screens in other organisms promise to reduce this bias. Here we present the results of the iBeetle screen, a large-scale, unbiased RNAi screen in the red flour beetle, Tribolium castaneum, which identifies gene functions in embryonic and postembryonic development, physiology and cell biology. The utility of Tribolium as a screening platform is demonstrated by the identification of genes involved in insect epithelial adhesion. This work transcends the restrictions of the candidate gene approach and opens fields of research not accessible in Drosophila. Unbiased screening for insect gene function has been largely restricted to Drosophila. Here, Schmitt-Engel et al. perform an unbiased large-scale RNAi screen in the red flour beetle Tribolium castaneum to identify putative gene functions.
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16
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Huang NN, Hunter CP. The RNA binding protein MEX-3 retains asymmetric activity in the early Caenorhabditis elegans embryo in the absence of asymmetric protein localization. Gene 2014; 554:160-73. [PMID: 25445286 DOI: 10.1016/j.gene.2014.10.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/23/2014] [Accepted: 10/25/2014] [Indexed: 10/24/2022]
Abstract
The RNA binding protein MEX-3 is required to restrict translation of pal-1, the Caenorhabditis elegans caudal homolog, to the posterior of the early embryo. MEX-3 is present uniformly throughout the newly fertilized embryo, but becomes depleted in the posterior by the 4-cell stage. This MEX-3 patterning requires the CCCH zinc-finger protein MEX-5, the RNA Recognition Motif protein SPN-4, and the kinase PAR-4. Genetic and biochemical evidence suggests that MEX-5 binds to MEX-3 in the anterior of the embryo, protecting MEX-3 from degradation and allowing it to bind the pal-1 3'UTR and repress translation. MEX-3 that is not bound to MEX-5 becomes inactivated by par-4, then targeted for spn-4 dependent degradation. After the 4-cell stage, residual MEX-3 is degraded in somatic cells, and only persists in the germline precursors. To better understand regulation of mex-3, GFP was fused to MEX-3 or regions of MEX-3 and expressed in developing oocytes. GFP::MEX-3 expressed in this manner can replace endogenous MEX-3, but surprisingly is not asymmetrically localized at the 4-cell stage. These results indicate that GFP::MEX-3 retains asymmetric activity even in the absence of asymmetric protein localization. Neither the mex-3 3'UTR nor protein degradation at the 4-cell stage is strictly required. A region of MEX-3 containing a glutamine-rich region and potential ubiquitination and phosphorylation sites is sufficient for soma-germline asymmetry. Results from mex-5/6 and spn-4(RNAi) suggest two pathways for MEX-3 degradation, an early spn-4 dependent pathway and a later spn-4 independent pathway. These results indicate that mex-3 activity is regulated at multiple levels, leading to rapid and robust regulation in the quickly developing early embryo.
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Affiliation(s)
- Nancy N Huang
- Molecular Biology Department, Colorado College, Colorado Springs, CO 80903, USA.
| | - Craig P Hunter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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Benton MA, Pavlopoulos A. Tribolium embryo morphogenesis: may the force be with you. BIOARCHITECTURE 2014; 4:16-21. [PMID: 24451992 DOI: 10.4161/bioa.27815] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Development of multicellular organisms depends on patterning and growth mechanisms encoded in the genome, but also on the physical properties and mechanical interactions of the constituent cells that interpret these genetic cues. This fundamental biological problem requires integrated studies at multiple levels of biological organization: from genes, to cell behaviors, to tissue morphogenesis. We have recently combined functional genetics with live imaging approaches in embryos of the insect Tribolium castaneum, in order to understand their remarkable transformation from a uniform single-layered blastoderm into a condensed multi-layered embryo covered by extensive extra-embryonic tissues. We first developed a quick and reliable methodology to fluorescently label various cell components in entire Tribolium embryos. Live imaging of labeled embryos at single cell resolution provided detailed descriptions of cell behaviors and tissue movements during normal embryogenesis. We then compared cell and tissue dynamics between wild-type and genetically perturbed embryos that exhibited altered relative proportions of constituent tissues. This systematic comparison led to a qualitative model of the molecular, cellular and tissue interactions that orchestrate the observed epithelial rearrangements. We expect this work to establish the Tribolium embryo as a powerful and attractive model system for biologists and biophysicists interested in the molecular, cellular and mechanical control of tissue morphogenesis.
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Affiliation(s)
- Matthew A Benton
- Laboratory for Development and Evolution; Department of Zoology; University of Cambridge; Cambridge, UK
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Benton MA, Akam M, Pavlopoulos A. Cell and tissue dynamics during Tribolium embryogenesis revealed by versatile fluorescence labeling approaches. Development 2013; 140:3210-20. [PMID: 23861059 PMCID: PMC3930475 DOI: 10.1242/dev.096271] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Studies on new arthropod models such as the beetle Tribolium castaneum are shifting our knowledge of embryonic patterning and morphogenesis beyond the Drosophila paradigm. In contrast to Drosophila, Tribolium embryos exhibit the short-germ type of development and become enveloped by extensive extra-embryonic membranes, the amnion and serosa. The genetic basis of these processes has been the focus of active research. Here, we complement genetic approaches with live fluorescence imaging of Tribolium embryos to make the link between gene function and morphogenetic cell behaviors during blastoderm formation and differentiation, germband condensation and elongation, and extra-embryonic development. We first show that transient labeling methods result in strong, homogeneous and persistent expression of fluorescent markers in Tribolium embryos, labeling the chromatin, membrane, cytoskeleton or combinations thereof. We then use co-injection of fluorescent markers with dsRNA for live imaging of embryos with disrupted caudal gene function caused by RNA interference. Using these approaches, we describe and compare cell and tissue dynamics in Tribolium embryos with wild-type and altered fate maps. We find that Tribolium germband condensation is effected by cell contraction and intercalation, with the latter being dependent on the anterior-posterior patterning system. We propose that germband condensation drives initiation of amnion folding, whereas expansion of the amniotic fold and closure of the amniotic cavity are likely driven by contraction of an actomyosin cable at the boundary between the amnion and serosa. Our methodology provides a comprehensive framework for testing quantitative models of patterning, growth and morphogenetic mechanisms in Tribolium and other arthropod species.
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Affiliation(s)
- Matthew A Benton
- Laboratory for Development and Evolution, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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MEX-3 proteins: recent insights on novel post-transcriptional regulators. Trends Biochem Sci 2013; 38:477-9. [PMID: 23999169 DOI: 10.1016/j.tibs.2013.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/12/2013] [Accepted: 08/12/2013] [Indexed: 11/21/2022]
Abstract
RNA-binding proteins of the evolutionarily-conserved MEX-3 family are mediators of post-transcriptional regulation in different organisms. Recent studies highlight their involvement in diverse physiological settings, including the maintenance of a balance between stem cell self-renewal and differentiation. Here, we draw attention to their putative role in tissue homeostasis and disease, particularly cancer.
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Chang CC, Hsiao YM, Huang TY, Cook CE, Shigenobu S, Chang TH. Noncanonical expression of caudal during early embryogenesis in the pea aphid Acyrthosiphon pisum: maternal cad-driven posterior development is not conserved. INSECT MOLECULAR BIOLOGY 2013; 22:442-455. [PMID: 23683148 DOI: 10.1111/imb.12035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Previously we identified anterior localization of hunchback (Aphb) mRNA in oocytes and early embryos of the parthenogenetic and viviparous pea aphid Acyrthosiphon pisum, suggesting that the breaking of anterior asymmetry in the oocytes leads to the formation of the anterior axis in embryos. In order to study posterior development in the asexual pea aphid, we cloned and analysed the developmental expression of caudal (Apcad), a posterior gene highly conserved in many animal phyla. We found that transcripts of Apcad were not detected in germaria, oocytes and embryos prior to the formation of the blastoderm in the asexual (viviparous) pea aphid. This unusual expression pattern differs from that of the existing insect models, including long- and short-germ insects, where maternal cad mRNA is passed to the early embryos and forms a posterior-anterior gradient. The first detectable Apcad expression occurred in the newly formed primordial germ cells and their adjacent blastodermal cells during late blastulation. From gastrulation onward, and as in other insects, Apcad mRNA is restricted to the posteriormost region of the germ band. Similarly, in the sexual (oviparous) oocytes we were able to identify anterior localization of Aphb mRNA but posterior localization of Apcad was not detected. This suggests that cad-driven posterior development is not conserved during early embryogenesis in asexual and sexual pea aphids.
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Affiliation(s)
- C-C Chang
- Laboratory for Genetics and Development, Department of Entomology/Institute of Biotechnology, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan.
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21
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MicroRNAs Act as Cofactors in Bicoid-Mediated Translational Repression. Curr Biol 2013; 23:1579-84. [DOI: 10.1016/j.cub.2013.06.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 05/14/2013] [Accepted: 06/17/2013] [Indexed: 12/31/2022]
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Peel AD, Schanda J, Grossmann D, Ruge F, Oberhofer G, Gilles AF, Schinko JB, Klingler M, Bucher G. Tc-knirps plays different roles in the specification of antennal and mandibular parasegment boundaries and is regulated by a pair-rule gene in the beetle Tribolium castaneum. BMC DEVELOPMENTAL BIOLOGY 2013; 13:25. [PMID: 23777260 PMCID: PMC3698154 DOI: 10.1186/1471-213x-13-25] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 06/12/2013] [Indexed: 01/03/2023]
Abstract
Background The Drosophila larval head is evolutionarily derived at the genetic and morphological level. In the beetle Tribolium castaneum, development of the larval head more closely resembles the ancestral arthropod condition. Unlike in Drosophila, a knirps homologue (Tc-kni) is required for development of the antennae and mandibles. However, published Tc-kni data are restricted to cuticle phenotypes and Tc-even-skipped and Tc-wingless stainings in knockdown embryos. Hence, it has remained unclear whether the entire antennal and mandibular segments depend on Tc-kni function, and whether the intervening intercalary segment is formed completely. We address these questions with a detailed examination of Tc-kni function. Results By examining the expression of marker genes in RNAi embryos, we show that Tc-kni is required only for the formation of the posterior parts of the antennal and mandibular segments (i.e. the parasegmental boundaries). Moreover, we find that the role of Tc-kni is distinct in these segments: Tc-kni is required for the initiation of the antennal parasegment boundary, but only for the maintenance of the mandibular parasegmental boundary. Surprisingly, Tc-kni controls the timing of expression of the Hox gene Tc-labial in the intercalary segment, although this segment does form in the absence of Tc-kni function. Unexpectedly, we find that the pair-rule gene Tc-even-skipped helps set the posterior boundary of Tc-kni expression in the mandible. Using the mutant antennaless, a likely regulatory Null mutation at the Tc-kni locus, we provide evidence that our RNAi studies represent a Null situation. Conclusions Tc-kni is required for the initiation of the antennal and the maintenance of the mandibular parasegmental boundaries. Tc-kni is not required for specification of the anterior regions of these segments, nor the intervening intercalary segment, confirming that Tc-kni is not a canonical ‘gap-gene’. Our finding that a gap gene orthologue is regulated by a pair rule gene adds to the view that the segmentation gene hierarchies differ between Tribolium and Drosophila upstream of the pair rule gene level. In Tribolium, as in Drosophila, head and trunk segmentation gene networks cooperate to pattern the mandibular segment, albeit involving Tc-kni as novel component.
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Affiliation(s)
- Andrew D Peel
- Institute of Molecular Biology and Biotechnology (IMBB), Foundation for Research and Technology - Hellas (FoRTH), Nikolaou Plastira 100, GR-70013, Heraklion, Crete, Greece
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Carter JM, Baker SC, Pink R, Carter DRF, Collins A, Tomlin J, Gibbs M, Breuker CJ. Unscrambling butterfly oogenesis. BMC Genomics 2013; 14:283. [PMID: 23622113 PMCID: PMC3654919 DOI: 10.1186/1471-2164-14-283] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/05/2013] [Indexed: 12/16/2022] Open
Abstract
Background Butterflies are popular model organisms to study physiological mechanisms
underlying variability in oogenesis and egg provisioning in response to
environmental conditions. Nothing is known, however, about; the
developmental mechanisms governing butterfly oogenesis, how polarity in the
oocyte is established, or which particular maternal effect genes regulate
early embryogenesis. To gain insights into these developmental mechanisms
and to identify the conserved and divergent aspects of butterfly oogenesis,
we analysed a de novo ovarian transcriptome of the Speckled Wood
butterfly Pararge aegeria (L.), and compared the results with known
model organisms such as Drosophila melanogaster and Bombyx
mori. Results A total of 17306 contigs were annotated, with 30% possibly novel or highly
divergent sequences observed. Pararge aegeria females expressed
74.5% of the genes that are known to be essential for D.
melanogaster oogenesis. We discuss the genes involved in all
aspects of oogenesis, including vitellogenesis and choriogenesis, plus those
implicated in hormonal control of oogenesis and transgenerational hormonal
effects in great detail. Compared to other insects, a number of significant
differences were observed in; the genes involved in stem cell maintenance
and differentiation in the germarium, establishment of oocyte polarity, and
in several aspects of maternal regulation of zygotic development. Conclusions This study provides valuable resources to investigate a number of divergent
aspects of butterfly oogenesis requiring further research. In order to fully
unscramble butterfly oogenesis, we also now also have the resources to
investigate expression patterns of oogenesis genes under a range of
environmental conditions, and to establish their function.
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Affiliation(s)
- Jean-Michel Carter
- Evolutionary Developmental Biology Research Group, Faculty of Health and Life Sciences, Department of Biological and Medical Sciences, Oxford Brookes University, Gipsy Lane, Headington, Oxford, OX3 0BP, UK
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Clayton AM, Cirimotich CM, Dong Y, Dimopoulos G. Caudal is a negative regulator of the Anopheles IMD pathway that controls resistance to Plasmodium falciparum infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2013; 39:323-332. [PMID: 23178401 PMCID: PMC3892953 DOI: 10.1016/j.dci.2012.10.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 10/11/2012] [Accepted: 10/12/2012] [Indexed: 06/02/2023]
Abstract
Malaria parasite transmission depends upon the successful development of Plasmodium in its Anopheles mosquito vector. The mosquito's innate immune system constitutes a major bottleneck for parasite population growth. We show here that in Anopheles gambiae, the midgut-specific transcription factor Caudal acts as a negative regulator in the Imd pathway-mediated immune response against the human malaria parasite Plasmodium falciparum. Caudal also modulates the mosquito midgut bacterial flora. RNAi-mediated silencing of Caudal enhanced the mosquito's resistance to bacterial infections and increased the transcriptional abundance of key immune effector genes. Interestingly, Caudal's silencing resulted in an increased lifespan of the mosquito, while it impaired reproductive fitness with respect to egg laying and hatching.
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Affiliation(s)
| | | | | | - George Dimopoulos
- Corresponding author. Address: W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, MD 21205, USA. Tel.: 1-443-287-0128. Fax: 1-410-955-0105.
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Kittelmann S, Ulrich J, Posnien N, Bucher G. Changes in anterior head patterning underlie the evolution of long germ embryogenesis. Dev Biol 2012. [PMID: 23201022 DOI: 10.1016/j.ydbio.2012.11.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Early embryonic stages differ significantly among related animal taxa while subsequent development converges at the conserved phylotypic stage before again diverging. Although this phenomenon has long been observed, its underlying genetic mechanisms remain enigmatic. The dipteran Drosophila melanogaster develops as a long germ embryo where the head anlagen form a cap at the anterior pole of the blastoderm. Consequently, the anterior and terminal maternal systems give crucial input for head patterning. However, in the short germ beetle Tribolium castaneum, as in most insects, the head anlagen is located at a ventral position distant from the anterior pole of the blastoderm. In line with these divergent embryonic anlagen, several differences in the axis formation between the insects have been discovered. We now ask to what extent patterning and morphogenesis of the anterior median region (AMR) of the head, including clypeolabral and stomodeal anlagen, differ among these insects. Unexpectedly, we find that Tc-huckebein is not a terminal gap gene and, unlike its Drosophila ortholog, is not involved in Tribolium head development. Instead, Tc-six3 acts upstream of Tc-crocodile and Tc-cap'n'collar to pattern posterior and anterior parts of the AMR, respectively. We further find that instead of huckebein, Tc-crocodile is required for stomodeum development by activating Tc-forkhead. Finally, a morphogenetic movement not found in Drosophila shapes the embryonic head of Tribolium. Apparently, with anterior displacement of the head anlagen during long germ evolution of Drosophila, the ancestral regulation by the bilaterian anterior control gene six3 was replaced by the anterior and terminal maternal systems, which were further elaborated by adding bicoid, tailless and huckebein as anterior regionalization genes.
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Affiliation(s)
- Sebastian Kittelmann
- Department of Evolutionary Genetics, Göttingen Center of Molecular Biology, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany.
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Heat shock-mediated misexpression of genes in the beetle Tribolium castaneum. Dev Genes Evol 2012; 222:287-98. [DOI: 10.1007/s00427-012-0412-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 06/29/2012] [Indexed: 12/18/2022]
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Asymmetrically expressed axin required for anterior development in Tribolium. Proc Natl Acad Sci U S A 2012; 109:7782-6. [PMID: 22552230 DOI: 10.1073/pnas.1116641109] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Canonical Wnt signaling has been implicated in an AP axis polarizing mechanism in most animals, despite limited evidence from arthropods. In the long-germ insect, Drosophila, Wnt signaling is not required for global AP patterning, but in short-germ insects including Tribolium castaneum, loss of Wnt signaling affects development of segments in the growth zone but not those defined in the blastoderm. To determine the effects of ectopic Wnt signaling, we analyzed the expression and function of axin, which encodes a highly conserved negative regulator of the pathway. We found Tc-axin transcripts maternally localized to the anterior pole in freshly laid eggs. Expression spread toward the posterior pole during the early cleavage stages, becoming ubiquitous by the time the germ rudiment formed. Tc-axin RNAi produced progeny phenotypes that ranged from mildly affected embryos with cuticles displaying a graded loss of anterior structures, to defective embryos that condensed at the posterior pole in the absence of serosa. Altered expression domains of several blastodermal markers indicated anterior expansion of posterior fates. Analysis of other canonical Wnt pathway components and the expansion of Tc-caudal expression, a Wnt target, suggest that the effects of Tc-axin depletion are mediated through this pathway and that Wnt signaling must be inhibited for proper anterior development in Tribolium. These studies provide unique evidence that canonical Wnt signaling must be carefully regulated along the AP axis in an arthropod, and support an ancestral role for Wnt activity in defining AP polarity and patterning in metazoan development.
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Schmitt-Engel C, Cerny AC, Schoppmeier M. A dual role for nanos and pumilio in anterior and posterior blastodermal patterning of the short-germ beetle Tribolium castaneum. Dev Biol 2012; 364:224-35. [DOI: 10.1016/j.ydbio.2012.01.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 01/09/2012] [Accepted: 01/20/2012] [Indexed: 11/15/2022]
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Andrioli LP. Toward new Drosophila paradigms. Genesis 2012; 50:585-98. [DOI: 10.1002/dvg.22019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/07/2012] [Accepted: 02/08/2012] [Indexed: 11/07/2022]
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El-Sherif E, Lynch JA, Brown SJ. Comparisons of the embryonic development of Drosophila, Nasonia, and Tribolium. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2012; 1:16-39. [PMID: 23801665 PMCID: PMC5323069 DOI: 10.1002/wdev.3] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Studying the embryogenesis of diverse insect species is crucial to understanding insect evolution. Here, we review current advances in understanding the development of two emerging model organisms: the wasp Nasonia vitripennis and the beetle Tribolium castaneum in comparison with the well-studied fruit fly Drosophila melanogaster. Although Nasonia represents the most basally branching order of holometabolous insects, it employs a derived long germband mode of embryogenesis, more like that of Drosophila, whereas Tribolium undergoes an intermediate germband mode of embryogenesis, which is more similar to the ancestral mechanism. Comparing the embryonic development and genetic regulation of early patterning events in these three insects has given invaluable insights into insect evolution. The similar mode of embryogenesis of Drosophila and Nasonia is reflected in their reliance on maternal morphogenetic gradients. However, they employ different genes as maternal factors, reflecting the evolutionary distance separating them. Tribolium, on the other hand, relies heavily on self-regulatory mechanisms other than maternal cues, reflecting its sequential nature of segmentation and the need for reiterated patterning.
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Affiliation(s)
- Ezzat El-Sherif
- Program of Genetics, Kansas State University, Manhattan, Kansas
| | - Jeremy A Lynch
- Institute for Developmental Biology, University of Cologne, Cologne, Germany
| | - Susan J Brown
- Division of Biology, Kansas State University, Manhattan, Kansas
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Kimelman D, Martin BL. Anterior-posterior patterning in early development: three strategies. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2011; 1:253-66. [PMID: 23801439 DOI: 10.1002/wdev.25] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The anterior-posterior (AP) axis is the most ancient of the embryonic axes and exists in most metazoans. Different animals use a wide variety of mechanisms to create this axis in the early embryo. In this study, we focus on three animals, including two insects (Drosophila and Tribolium) and a vertebrate (zebrafish) to examine different strategies used to form the AP axis. While Drosophila forms the entire axis within a syncytial blastoderm using transcription factors as morphogens, zebrafish uses signaling factors in a cellularized embryo, progressively forming the AP axis over the course of a day. Tribolium uses an intermediate strategy that has commonalities with both Drosophila and zebrafish. We discuss the specific molecular mechanisms used to create the AP axis and identify conserved features.
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Affiliation(s)
- David Kimelman
- Department of Biochemistry, University of Washington, Seattle, WA, USA.
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Pechmann M, Khadjeh S, Turetzek N, McGregor AP, Damen WGM, Prpic NM. Novel function of Distal-less as a gap gene during spider segmentation. PLoS Genet 2011; 7:e1002342. [PMID: 22028676 PMCID: PMC3197691 DOI: 10.1371/journal.pgen.1002342] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/29/2011] [Indexed: 12/27/2022] Open
Abstract
Despite many aspects of the regulation of segmentation being conserved among arthropods, the evolution of novel gene functions has played an important role in the evolution of developmental regulation and the emergence of new segmental structures. Moreover the study of such novel gene functions can be informative with respect to the patterns and direction of evolutionary changes in developmental programs. The homeobox gene Distal-less (Dll) is known for its conserved function in appendage development in metazoans. In arthropods, Dll is required for the specification of distal appendage structures. Here we describe a novel and unexpected role of Dll in the spider Achaearanea tepidariorum. We detect At-Dll transcripts not only in the appendages, but unexpectedly also in an anterior domain during early development, prior to the specification of the limb primordia. A similar early Dll domain is present in the distantly related spider Pholcus phalangioides. In A. tepidariorum this early At-Dll expression is required for head segmentation. RNA interference results in spiders that lack either the first or the first and the second walking leg segments. The early At-Dll expression is also required for the activation of the segment polarity genes engrailed and hedgehog in this region. Our work identifies the Distal-less gene as a novel factor in anterior spider segmentation with a gap gene-like function. This novel role of Dll is interesting because Dll expression is reduced in this region in crustaceans and the homologous insect segment, the mandible segment, does not express Dll and does not require this gene for patterning. We therefore discuss the possible implications of our results for understanding the evolution and diversification of the mandible segment. The development and segmentation of the head of the fly Drosophila is one of the best-studied examples of how tissues become genetically specified during embryonic development. However, the mechanisms for head segmentation vary considerably among the arthropods. This is on the one hand surprising because the head consists of the same series of segments in all arthropods. On the other hand, changes in gene regulatory networks are the basis for the evolution of novel morphologies and biodiversity. In this paper, we describe our study of the Distal-less gene in the spider Achaearanea tepidariorum. Distal-less is well-known for its function in appendage development, but here we show that in the spider it also has a novel function during head segmentation that is not found in Drosophila or other arthropods. In Achaearanea the Distal-less gene is necessary for the formation of the first walking-leg segment, which is homologous to the mandible segment of the head of other arthropods. Intriguingly, the mandible segment in other arthropods exhibits reduced or missing Distal-less expression. Thus, our results suggest that this difference in the role of Distal-less in the first walking-leg/mandible segment of spiders and other arthropods may underlie the diversification of this segment.
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Affiliation(s)
- Matthias Pechmann
- Georg-August-Universität Göttingen, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Abteilung für Entwicklungsbiologie, GZMB Ernst-Caspari-Haus, Göttingen, Germany
| | - Sara Khadjeh
- Georg-August-Universität Göttingen, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Abteilung für Entwicklungsbiologie, GZMB Ernst-Caspari-Haus, Göttingen, Germany
| | - Natascha Turetzek
- Georg-August-Universität Göttingen, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Abteilung für Entwicklungsbiologie, GZMB Ernst-Caspari-Haus, Göttingen, Germany
| | - Alistair P. McGregor
- Institut für Populationsgenetik, Veterinärmedizinische Universität Wien, Vienna, Austria
- School of Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Wim G. M. Damen
- Friedrich-Schiller-Universität Jena, Department of Genetics, Jena, Germany
| | - Nikola-Michael Prpic
- Georg-August-Universität Göttingen, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Abteilung für Entwicklungsbiologie, GZMB Ernst-Caspari-Haus, Göttingen, Germany
- * E-mail:
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Kerner P, Degnan SM, Marchand L, Degnan BM, Vervoort M. Evolution of RNA-binding proteins in animals: insights from genome-wide analysis in the sponge Amphimedon queenslandica. Mol Biol Evol 2011; 28:2289-303. [PMID: 21325094 DOI: 10.1093/molbev/msr046] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
RNA-binding proteins (RBPs) are key players in various biological processes, most notably regulation of gene expression at the posttranscriptional level. Although many RBPs have been carefully studied in model organisms, very few studies have addressed the evolution of these proteins at the scale of the animal kingdom. We identified a large set of putative RBPs encoded by the genome of the demosponge Amphimedon queenslandica, a species representing a basal animal lineage. We compared the Amphimedon RBPs with those encoded by the genomes of two bilaterians (human and Drosophila), representatives of two other basal metazoan lineages (a placozoan and a cnidarian), a choanoflagellate (probable sister group of animals), and two fungi. We established the evolutionary history of 32 families of RBPs and found that most of the diversity of RBPs present in contemporary metazoans, including humans, was already established in the last common ancestor (LCA) of animals. This includes RBPs known to be involved in key processes in bilaterians, such as development, stem and/or germ cells properties, and noncoding RNA pathways. From this analysis, we infer that a complex toolkit of RBPs was present in the LCA of animals and that it has been recruited to perform new functions during early animal evolution, in particular in relation to the acquisition of multicellularity.
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Affiliation(s)
- Pierre Kerner
- Development and Neurobiology Programme, Institut Jacques Monod, Centre national de la recherche scientifique/Université Paris Diderot-Paris 7, Paris cedex, France
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Peel AD, Averof M. Early asymmetries in maternal transcript distribution associated with a cortical microtubule network and a polar body in the beetle Tribolium castaneum. Dev Dyn 2011; 239:2875-87. [PMID: 20857499 DOI: 10.1002/dvdy.22423] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The localization of maternal mRNAs during oogenesis plays a central role in axial specification in some insects. Here we describe a polar body-associated asymmetry in maternal transcript distribution in pre-blastoderm eggs of the beetle Tribolium castaneum. Since the position of the polar body marks the future dorsal side of the embryo, we have investigated whether this asymmetry in mRNA distribution plays a role in dorsal-ventral axis specification. Whilst our results suggest polar body-associated transcripts do not play a significant role in specifying the DV axis, at least during early embryogenesis, we do find that the polar body is closely associated with a cortical microtubule network (CMN), which may play a role in the localization of transcripts during oogenesis. Transcripts of the gene T.c.pangolin co-localize with the CMN at the time of their anterior localization during oogenesis and their anterior localization is disrupted by the microtubule-depolymerizing agent colcemid.
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Affiliation(s)
- Andrew D Peel
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas, Crete, Greece.
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Posnien N, Schinko JB, Kittelmann S, Bucher G. Genetics, development and composition of the insect head--a beetle's view. ARTHROPOD STRUCTURE & DEVELOPMENT 2010; 39:399-410. [PMID: 20800703 DOI: 10.1016/j.asd.2010.08.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/08/2010] [Accepted: 08/15/2010] [Indexed: 05/29/2023]
Abstract
Many questions regarding evolution and ontogeny of the insect head remain open. Likewise, the genetic basis of insect head development is poorly understood. Recently, the investigation of gene expression data and the analysis of patterning gene function have revived interest in insect head development. Here, we argue that the red flour beetle Tribolium castaneum is a well suited model organism to spearhead research with respect to the genetic control of insect head development. We review recent molecular data and discuss its bearing on early development and morphogenesis of the head. We present a novel hypothesis on the ontogenetic origin of insect head sutures and review recent insights into the question on the origin of the labrum. Further, we argue that the study of developmental genes may identify the elusive anterior non-segmental region and present some evidence in favor of its existence. With respect to the question of evolution of patterning we show that the head Anlagen of the fruit fly Drosophila melanogaster and Tribolium differ considerably and we review profound differences of their genetic regulation. Finally, we discuss which insect model species might help us to answer the open questions concerning the genetic regulation of head development and its evolution.
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Affiliation(s)
- Nico Posnien
- Institute for Population Genetics, University of Veterinary Medicine Vienna, Veterinärplatz 1, Vienna, Austria
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JAK-STAT signalling is required throughout telotrophic oogenesis and short-germ embryogenesis of the beetle Tribolium. Dev Biol 2010; 350:169-82. [PMID: 20974121 DOI: 10.1016/j.ydbio.2010.10.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Revised: 10/04/2010] [Accepted: 10/15/2010] [Indexed: 12/16/2022]
Abstract
In Drosophila, the JAK-STAT signalling pathway regulates a broad array of developmental functions including segmentation and oogenesis. Here we analysed the functions of Tribolium JAK-STAT signalling factors and of Suppressor Of Cytokine Signalling (SOCS) orthologues, which are known to function as negative regulators of JAK-STAT signalling, during telotrophic oogenesis and short-germ embryogenesis. The beetle Tribolium features telotrophic ovaries, which differ fundamentally from the polytrophic ovary of Drosophila. While we found the requirement for JAK-STAT signalling in specifying the interfollicular stalk to be principally conserved, we demonstrate that these genes also have early and presumably telotrophic specific functions. Moreover, we show that the SOCS genes crucially contribute to telotrophic Tribolium oogenesis, as their inactivation by RNAi results in compound follicles. During short-germ embryogenesis, JAK-STAT signalling is required in the maintenance of segment primordia, indicating that this signalling cascade acts in the framework of the segment-polarity network. In addition, we demonstrate that JAK-STAT signalling crucially contributes to early anterior patterning. We posit that this signalling cascade is involved in achieving accurate levels of expression of individual pair-rule and gap gene domains in early embryonic patterning.
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Kotkamp K, Klingler M, Schoppmeier M. Apparent role of Tribolium orthodenticle in anteroposterior blastoderm patterning largely reflects novel functions in dorsoventral axis formation and cell survival. Development 2010; 137:1853-62. [PMID: 20431120 DOI: 10.1242/dev.047043] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In the short-germ beetle Tribolium castaneum, the head gap gene orthodenticle (Tc-otd) has been proposed to functionally substitute for bicoid, the anterior morphogen unique to higher dipterans. In this study we reanalyzed the function of Tc-otd. We obtained a similar range of cuticle phenotypes as in previously described RNAi experiments; however, we noticed unexpected effects on blastodermal cell fates. First, we found that Tc-otd is essential for dorsoventral patterning. RNAi depletion results in lateralized embryos, a fate map change that by itself can explain the observed loss of the anterior head, which is a ventral anlage in Tribolium. We find that this effect is due to diminished expression of short gastrulation (sog), a gene essential for establishment of the Decapentaplegic (Dpp) gradient in this species. Second, we found that gnathal segment primordia in Tc-otd RNAi embryos are shifted anteriorly but otherwise appear patterned normally. This anteroposterior (AP) fate map shift might largely be due to diminished zen-1 expression and is not responsible for the severe segmentation defects observed in some Tc-otd RNAi embryos. As neither Tc-sog nor Tc-zen-1 probably requires Otd gradient-mediated positional information, we posit that the blastoderm function of Tc-Otd depends on its initial homogeneous maternal expression and that this maternal factor does not provide significant positional information for Tribolium blastoderm embryos.
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Affiliation(s)
- Kay Kotkamp
- Department of Biology, Developmental Biology Unit, Erlangen University, 90158 Erlangen, Germany.
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