1
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Kato Y, Yoshida S, Kato T. Missing pieces of the pituitary puzzle: participation of extra-adenohypophyseal placode-lineage cells in the adult pituitary gland. Cell Tissue Res 2023; 394:487-496. [PMID: 37650920 DOI: 10.1007/s00441-023-03829-8] [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: 03/27/2023] [Accepted: 08/14/2023] [Indexed: 09/01/2023]
Abstract
The pituitary gland is a major endocrine tissue composing of two distinct entities, the adenohypophysis (anterior pituitary, cranial placode origin) and the neurohypophysis (posterior pituitary, neural ectoderm origin), and plays important roles in maintaining vital homeostasis. This tissue is maintained by a slow, consistent cell-renewal system of adult stem/progenitor cells. Recent accumulating evidence shows that neural crest-, head mesenchyme-, and endoderm lineage cells invade during pituitary development and contribute to the maintenance of the adult pituitary gland. Based on these novel observations, this article discusses whether these lineage cells are involved in pituitary organogenesis, maintenance, regeneration, dysplasia, or tumors.
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Affiliation(s)
- Yukio Kato
- Institute for Endocrinology, Meiji University, 1-1-1 Higashi-Mita, Tama-Ku, Kawasaki, Kanagawa, 214-8571, Japan.
| | - Saishu Yoshida
- Department of Biochemistry, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-Ku, Tokyo, 105-8461, Japan
| | - Takako Kato
- Institute for Endocrinology, Meiji University, 1-1-1 Higashi-Mita, Tama-Ku, Kawasaki, Kanagawa, 214-8571, Japan
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2
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Bañón A, Alsina B. Pioneer statoacoustic neurons guide neuroblast behaviour during otic ganglion assembly. Development 2023; 150:dev201824. [PMID: 37938828 PMCID: PMC10651105 DOI: 10.1242/dev.201824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 09/07/2023] [Indexed: 11/10/2023]
Abstract
Cranial ganglia are aggregates of sensory neurons that mediate distinct types of sensation. The statoacoustic ganglion (SAG) develops into several lobes that are spatially arranged to connect appropriately with hair cells of the inner ear. To investigate the cellular behaviours involved in the 3D organization of the SAG, we use high-resolution confocal imaging of single-cell, labelled zebrafish neuroblasts (NBs), photoconversion, photoablation, and genetic perturbations. We show that otic NBs delaminate out of the otic epithelium in an epithelial-mesenchymal transition-like manner, rearranging apical polarity and primary cilia proteins. We also show that, once delaminated, NBs require RhoGTPases in order to perform active migration. Furthermore, tracking of recently delaminated NBs revealed their directed migration and coalescence around a small population of pioneer SAG neurons. These pioneer SAG neurons, not from otic placode origin, populate the coalescence region before otic neurogenesis begins and their ablation disrupts delaminated NB migratory pathways, consequentially affecting SAG shape. Altogether, this work shows for the first time the role of pioneer SAG neurons in orchestrating SAG development.
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Affiliation(s)
- Aitor Bañón
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra-Parc de Recerca Biomèdica de Barcelona, Dr Aiguader 88, 08003 Barcelona, Spain
| | - Berta Alsina
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra-Parc de Recerca Biomèdica de Barcelona, Dr Aiguader 88, 08003 Barcelona, Spain
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3
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Klein SL, Tavares ALP, Peterson M, Sullivan CH, Moody SA. Repressive Interactions Between Transcription Factors Separate Different Embryonic Ectodermal Domains. Front Cell Dev Biol 2022; 10:786052. [PMID: 35198557 PMCID: PMC8859430 DOI: 10.3389/fcell.2022.786052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
The embryonic ectoderm is composed of four domains: neural plate, neural crest, pre-placodal region (PPR) and epidermis. Their formation is initiated during early gastrulation by dorsal-ventral and anterior-posterior gradients of signaling factors that first divide the embryonic ectoderm into neural and non-neural domains. Next, the neural crest and PPR domains arise, either via differential competence of the neural and non-neural ectoderm (binary competence model) or via interactions between the neural and non-neural ectoderm tissues to produce an intermediate neural border zone (NB) (border state model) that subsequently separates into neural crest and PPR. Many previous gain- and loss-of-function experiments demonstrate that numerous TFs are expressed in initially overlapping zones that gradually resolve into patterns that by late neurula stages are characteristic of each of the four domains. Several of these studies suggested that this is accomplished by a combination of repressive TF interactions and competence to respond to local signals. In this study, we ectopically expressed TFs that at neural plate stages are characteristic of one domain in a different domain to test whether they act cell autonomously as repressors. We found that almost all tested TFs caused reduced expression of the other TFs. At gastrulation these effects were strictly within the lineage-labeled cells, indicating that the effects were cell autonomous, i.e., due to TF interactions within individual cells. Analysis of previously published single cell RNAseq datasets showed that at the end of gastrulation, and continuing to neural tube closure stages, many ectodermal cells express TFs characteristic of more than one neural plate stage domain, indicating that different TFs have the opportunity to interact within the same cell. At neurula stages repression was observed both in the lineage-labeled cells and in adjacent cells not bearing detectable lineage label, suggesting that cell-to-cell signaling has begun to contribute to the separation of the domains. Together, these observations directly demonstrate previous suggestions in the literature that the segregation of embryonic ectodermal domains initially involves cell autonomous, repressive TF interactions within an individual cell followed by the subsequent advent of non-cell autonomous signaling to neighbors.
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Affiliation(s)
- Steven L Klein
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, D.C., DC, United States
| | - Andre L P Tavares
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, D.C., DC, United States
| | - Meredith Peterson
- Department of Biology, State College, Penn State University, University Park, PA, United States
| | | | - Sally A Moody
- Department of Anatomy and Cell Biology, The George Washington University School of Medicine and Health Sciences, Washington, D.C., DC, United States
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4
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Williams RM, Lukoseviciute M, Sauka-Spengler T, Bronner ME. Single-cell atlas of early chick development reveals gradual segregation of neural crest lineage from the neural plate border during neurulation. eLife 2022; 11:74464. [PMID: 35088714 PMCID: PMC8798042 DOI: 10.7554/elife.74464] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/01/2021] [Indexed: 12/16/2022] Open
Abstract
The epiblast of vertebrate embryos is comprised of neural and non-neural ectoderm, with the border territory at their intersection harboring neural crest and cranial placode progenitors. Here, we a generate single-cell atlas of the developing chick epiblast from late gastrulation through early neurulation stages to define transcriptional changes in the emerging ‘neural plate border’ as well as other regions of the epiblast. Focusing on the border territory, the results reveal gradual establishment of heterogeneous neural plate border signatures, including novel genes that we validate by fluorescent in situ hybridization. Developmental trajectory analysis infers that segregation of neural plate border lineages only commences at early neurulation, rather than at gastrulation as previously predicted. We find that cells expressing the prospective neural crest marker Pax7 contribute to multiple lineages, and a subset of premigratory neural crest cells shares a transcriptional signature with their border precursors. Together, our results suggest that cells at the neural plate border remain heterogeneous until early neurulation, at which time progenitors become progressively allocated toward defined neural crest and placode lineages. The data also can be mined to reveal changes throughout the developing epiblast.
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Affiliation(s)
- Ruth M Williams
- California Institute of Technology, Division of Biology and Biological engineering, Pasadena, United States.,University of Oxford, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, Oxford, United Kingdom
| | - Martyna Lukoseviciute
- University of Oxford, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, Oxford, United Kingdom
| | - Tatjana Sauka-Spengler
- University of Oxford, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, Oxford, United Kingdom
| | - Marianne E Bronner
- California Institute of Technology, Division of Biology and Biological engineering, Pasadena, United States
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5
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Stundl J, Bertucci PY, Lauri A, Arendt D, Bronner ME. Evolution of new cell types at the lateral neural border. Curr Top Dev Biol 2021; 141:173-205. [PMID: 33602488 DOI: 10.1016/bs.ctdb.2020.11.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During the course of evolution, animals have become increasingly complex by the addition of novel cell types and regulatory mechanisms. A prime example is represented by the lateral neural border, known as the neural plate border in vertebrates, a region of the developing ectoderm where presumptive neural and non-neural tissue meet. This region has been intensively studied as the source of two important embryonic cell types unique to vertebrates-the neural crest and the ectodermal placodes-which contribute to diverse differentiated cell types including the peripheral nervous system, pigment cells, bone, and cartilage. How did these multipotent progenitors originate in animal evolution? What triggered the elaboration of the border during the course of chordate evolution? How is the lateral neural border patterned in various bilaterians and what is its fate? Here, we review and compare the development and fate of the lateral neural border in vertebrates and invertebrates and we speculate about its evolutionary origin. Taken together, the data suggest that the lateral neural border existed in bilaterian ancestors prior to the origin of vertebrates and became a developmental source of exquisite evolutionary change that frequently enabled the acquisition of new cell types.
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Affiliation(s)
- Jan Stundl
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | | | | | - Detlev Arendt
- European Molecular Biology Laboratory, Heidelberg, Germany.
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States.
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6
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Thawani A, Groves AK. Building the Border: Development of the Chordate Neural Plate Border Region and Its Derivatives. Front Physiol 2020; 11:608880. [PMID: 33364980 PMCID: PMC7750469 DOI: 10.3389/fphys.2020.608880] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/19/2020] [Indexed: 01/04/2023] Open
Abstract
The paired cranial sensory organs and peripheral nervous system of vertebrates arise from a thin strip of cells immediately adjacent to the developing neural plate. The neural plate border region comprises progenitors for four key populations of cells: neural plate cells, neural crest cells, the cranial placodes, and epidermis. Putative homologues of these neural plate border derivatives can be found in protochordates such as amphioxus and tunicates. In this review, we summarize key signaling pathways and transcription factors that regulate the inductive and patterning events at the neural plate border region that give rise to the neural crest and placodal lineages. Gene regulatory networks driven by signals from WNT, fibroblast growth factor (FGF), and bone morphogenetic protein (BMP) signaling primarily dictate the formation of the crest and placodal lineages. We review these studies and discuss the potential of recent advances in spatio-temporal transcriptomic and epigenomic analyses that would allow a mechanistic understanding of how these signaling pathways and their downstream transcriptional cascades regulate the formation of the neural plate border region.
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Affiliation(s)
- Ankita Thawani
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
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7
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Seal S, Monsoro-Burq AH. Insights Into the Early Gene Regulatory Network Controlling Neural Crest and Placode Fate Choices at the Neural Border. Front Physiol 2020; 11:608812. [PMID: 33324244 PMCID: PMC7726110 DOI: 10.3389/fphys.2020.608812] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/02/2020] [Indexed: 12/30/2022] Open
Abstract
The neural crest (NC) cells and cranial placodes are two ectoderm-derived innovations in vertebrates that led to the acquisition of a complex head structure required for a predatory lifestyle. They both originate from the neural border (NB), a portion of the ectoderm located between the neural plate (NP), and the lateral non-neural ectoderm. The NC gives rise to a vast array of tissues and cell types such as peripheral neurons and glial cells, melanocytes, secretory cells, and cranial skeletal and connective cells. Together with cells derived from the cranial placodes, which contribute to sensory organs in the head, the NC also forms the cranial sensory ganglia. Multiple in vivo studies in different model systems have uncovered the signaling pathways and genetic factors that govern the positioning, development, and differentiation of these tissues. In this literature review, we give an overview of NC and placode development, focusing on the early gene regulatory network that controls the formation of the NB during early embryonic stages, and later dictates the choice between the NC and placode progenitor fates.
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Affiliation(s)
- Subham Seal
- Université Paris-Saclay, CNRS UMR 3347, INSERM U1021, Orsay, France.,Institut Curie Research Division, PSL Research University, Orsay Cedex, France
| | - Anne H Monsoro-Burq
- Université Paris-Saclay, CNRS UMR 3347, INSERM U1021, Orsay, France.,Institut Curie Research Division, PSL Research University, Orsay Cedex, France.,Institut Universitaire de France, Paris, France
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8
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Zhao D, Chen S, Horie T, Gao Y, Bao H, Liu X. Comparison of differentiation gene batteries for migratory mechanosensory neurons across bilaterians. Evol Dev 2020; 22:438-450. [PMID: 32078235 DOI: 10.1111/ede.12331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In embryos of distantly related bilaterian phyla, their lateral neural borders give rise to the peripheral nervous system elements, including various mechanosensory cells derived from migratory precursors, such as hair cells and dorsal root ganglion (DRG) neurons in vertebrates, bipolar tail neuron (BTN) in Ciona, chordotonal organ in Drosophila, and AVM/PVM in Caenorhabditis elegans. Developmental genetics studies had revealed a couple of transcription factors (TFs) regulating differentiation of mechanosensory cells shared by vertebrates and arthropods. However, unbiased systematic profiling of regulators is needed to demonstrate conservation of differentiation gene batteries for mechanosensory cells across bilaterians. At first, we observed that in both C. elegans Q neuroblasts and Drosophila lateral neuroectoderm, conserved NPB specifier Msx/vab-15 regulates Atoh1/lin-32, supporting the homology of mechanosensory neuron development in lateral neural border lineage of Ecdysozia. So we used C. elegans as a protostomia model. Single-cell resolution expression profiling of TFs and genetic analysis revealed a differentiation gene battery (Atonh1/lin-32, Drg11/alr-1, Gfi1/pag-3, Lhx5/mec-3, and Pou4/unc-86) for AVM/PVM mechanosensory neurons. The worm-gene battery significantly overlaps with both that of placode-derived Atonh1/lin-32-dependent hair cells and that of NPB-derived Neurogenin-dependent DRG neurons in vertebrates, supporting the homology of molecular mechanisms underlying the differentiation of neural border-derived mechanosensory cells between protostome and deuterostome. At last, Ciona BTN, the homolog of vertebrate DRG, also expresses Atonh1/lin-32, further supporting the homology notion and indicating a common origin of hair cells and DRG in vertebrate lineage.
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Affiliation(s)
- Di Zhao
- School of Life Sciences, Capital Normal University, Beijing, China.,Ministry of Education Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Siyu Chen
- Ministry of Education Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Takeo Horie
- Shimoda Marine Research Center, University of Tsukuba, Shimoda, Shizuoka, Japan
| | - Yimeng Gao
- School of Life Sciences, Capital Normal University, Beijing, China
| | - Hongcun Bao
- Department of Genetics, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiao Liu
- School of Life Sciences, Capital Normal University, Beijing, China.,Ministry of Education Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
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9
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Rocha M, Singh N, Ahsan K, Beiriger A, Prince VE. Neural crest development: insights from the zebrafish. Dev Dyn 2019; 249:88-111. [PMID: 31591788 DOI: 10.1002/dvdy.122] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/21/2019] [Accepted: 09/22/2019] [Indexed: 12/12/2022] Open
Abstract
Our understanding of the neural crest, a key vertebrate innovation, is built upon studies of multiple model organisms. Early research on neural crest cells (NCCs) was dominated by analyses of accessible amphibian and avian embryos, with mouse genetics providing complementary insights in more recent years. The zebrafish model is a relative newcomer to the field, yet it offers unparalleled advantages for the study of NCCs. Specifically, zebrafish provide powerful genetic and transgenic tools, coupled with rapidly developing transparent embryos that are ideal for high-resolution real-time imaging of the dynamic process of neural crest development. While the broad principles of neural crest development are largely conserved across vertebrate species, there are critical differences in anatomy, morphogenesis, and genetics that must be considered before information from one model is extrapolated to another. Here, our goal is to provide the reader with a helpful primer specific to neural crest development in the zebrafish model. We focus largely on the earliest events-specification, delamination, and migration-discussing what is known about zebrafish NCC development and how it differs from NCC development in non-teleost species, as well as highlighting current gaps in knowledge.
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Affiliation(s)
- Manuel Rocha
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois
| | - Noor Singh
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois
| | - Kamil Ahsan
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois
| | - Anastasia Beiriger
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois
| | - Victoria E Prince
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois.,Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois
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10
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Prasad MS, Charney RM, García-Castro MI. Specification and formation of the neural crest: Perspectives on lineage segregation. Genesis 2019; 57:e23276. [PMID: 30576078 PMCID: PMC6570420 DOI: 10.1002/dvg.23276] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/17/2018] [Accepted: 12/18/2018] [Indexed: 12/21/2022]
Abstract
The neural crest is a fascinating embryonic population unique to vertebrates that is endowed with remarkable differentiation capacity. Thought to originate from ectodermal tissue, neural crest cells generate neurons and glia of the peripheral nervous system, and melanocytes throughout the body. However, the neural crest also generates many ectomesenchymal derivatives in the cranial region, including cell types considered to be of mesodermal origin such as cartilage, bone, and adipose tissue. These ectomesenchymal derivatives play a critical role in the formation of the vertebrate head, and are thought to be a key attribute at the center of vertebrate evolution and diversity. Further, aberrant neural crest cell development and differentiation is the root cause of many human pathologies, including cancers, rare syndromes, and birth malformations. In this review, we discuss the current findings of neural crest cell ontogeny, and consider tissue, cell, and molecular contributions toward neural crest formation. We further provide current perspectives into the molecular network involved during the segregation of the neural crest lineage.
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Affiliation(s)
- Maneeshi S Prasad
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California
| | - Rebekah M Charney
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California
| | - Martín I García-Castro
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, California
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11
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Zhao D, Chen S, Liu X. Lateral neural borders as precursors of peripheral nervous systems: A comparative view across bilaterians. Dev Growth Differ 2018; 61:58-72. [DOI: 10.1111/dgd.12585] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 11/14/2018] [Accepted: 11/14/2018] [Indexed: 01/13/2023]
Affiliation(s)
- Di Zhao
- School of Life Sciences; Capital Normal University; Beijing China
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; School of Life Sciences; Tsinghua University; Beijing China
| | - Siyu Chen
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; School of Life Sciences; Tsinghua University; Beijing China
| | - Xiao Liu
- School of Life Sciences; Capital Normal University; Beijing China
- Ministry of Education Key Laboratory of Bioinformatics; Center for Synthetic and Systems Biology; School of Life Sciences; Tsinghua University; Beijing China
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12
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Shared evolutionary origin of vertebrate neural crest and cranial placodes. Nature 2018; 560:228-232. [PMID: 30069052 PMCID: PMC6390964 DOI: 10.1038/s41586-018-0385-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 06/13/2018] [Indexed: 12/21/2022]
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13
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Pla P, Monsoro-Burq AH. The neural border: Induction, specification and maturation of the territory that generates neural crest cells. Dev Biol 2018; 444 Suppl 1:S36-S46. [PMID: 29852131 DOI: 10.1016/j.ydbio.2018.05.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 05/23/2018] [Accepted: 05/23/2018] [Indexed: 11/17/2022]
Abstract
The neural crest is induced at the edge between the neural plate and the nonneural ectoderm, in an area called the neural (plate) border, during gastrulation and neurulation. In recent years, many studies have explored how this domain is patterned, and how the neural crest is induced within this territory, that also participates to the prospective dorsal neural tube, the dorsalmost nonneural ectoderm, as well as placode derivatives in the anterior area. This review highlights the tissue interactions, the cell-cell signaling and the molecular mechanisms involved in this dynamic spatiotemporal patterning, resulting in the induction of the premigratory neural crest. Collectively, these studies allow building a complex neural border and early neural crest gene regulatory network, mostly composed by transcriptional regulations but also, more recently, including novel signaling interactions.
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Affiliation(s)
- Patrick Pla
- Univ. Paris Sud, Université Paris Saclay, CNRS UMR 3347, INSERM U1021, Centre Universitaire, 15, rue Georges Clémenceau, F-91405 Orsay, France; Institut Curie Research Division, PSL Research University, CNRS UMR 3347, INSERM U1021, F-91405 Orsay, France
| | - Anne H Monsoro-Burq
- Univ. Paris Sud, Université Paris Saclay, CNRS UMR 3347, INSERM U1021, Centre Universitaire, 15, rue Georges Clémenceau, F-91405 Orsay, France; Institut Curie Research Division, PSL Research University, CNRS UMR 3347, INSERM U1021, F-91405 Orsay, France; Institut Universitaire de France, F-75005, Paris.
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14
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Sato S, Furuta Y, Kawakami K. Regulation of continuous but complex expression pattern of Six1 during early sensory development. Dev Dyn 2017; 247:250-261. [PMID: 29106072 DOI: 10.1002/dvdy.24603] [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: 06/28/2017] [Revised: 10/17/2017] [Accepted: 10/31/2017] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND In vertebrates, cranial sensory placodes give rise to neurosensory and endocrine structures, such as the olfactory epithelium, inner ear, and anterior pituitary. We report here the establishment of a transgenic mouse line that expresses Cre recombinase under the control of Six1-21, a major placodal enhancer of the homeobox gene Six1. RESULTS In the new Cre-expressing line, mSix1-21-NLSCre, the earliest Cre-mediated recombination was induced at embryonic day 8.5 in the region overlapping with the otic-epibranchial progenitor domain (OEPD), a transient, common precursor domain for the otic and epibranchial placodes. Recombination was later observed in the OEPD-derived structures (the entire inner ear and the VIIth-Xth cranial sensory ganglia), olfactory epithelium, anterior pituitary, pharyngeal ectoderm and pouches. Other Six1-positive structures, such as salivary/lacrimal glands and limb buds, were also positive for recombination. Moreover, comparison with another mouse line expressing Cre under the control of the sensory neuron enhancer, Six1-8, indicated that the continuous and complex expression pattern of Six1 during sensory organ formation is pieced together by separate enhancers. CONCLUSIONS mSix1-21-NLSCre has several unique characteristics to make it suitable for analysis of cell lineage and gene function in sensory placodes as well as nonplacodal Six1-positive structures. Developmental Dynamics 247:250-261, 2018. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Shigeru Sato
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Yasuhide Furuta
- Animal Resource Development Unit and Genetic Engineering Team, Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies (CLST), Kobe, Hyogo, Japan
| | - Kiyoshi Kawakami
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan
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15
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Conserved gene regulatory module specifies lateral neural borders across bilaterians. Proc Natl Acad Sci U S A 2017; 114:E6352-E6360. [PMID: 28716930 DOI: 10.1073/pnas.1704194114] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The lateral neural plate border (NPB), the neural part of the vertebrate neural border, is composed of central nervous system (CNS) progenitors and peripheral nervous system (PNS) progenitors. In invertebrates, PNS progenitors are also juxtaposed to the lateral boundary of the CNS. Whether there are conserved molecular mechanisms determining vertebrate and invertebrate lateral neural borders remains unclear. Using single-cell-resolution gene-expression profiling and genetic analysis, we present evidence that orthologs of the NPB specification module specify the invertebrate lateral neural border, which is composed of CNS and PNS progenitors. First, like in vertebrates, the conserved neuroectoderm lateral border specifier Msx/vab-15 specifies lateral neuroblasts in Caenorhabditis elegans Second, orthologs of the vertebrate NPB specification module (Msx/vab-15, Pax3/7/pax-3, and Zic/ref-2) are significantly enriched in worm lateral neuroblasts. In addition, like in other bilaterians, the expression domain of Msx/vab-15 is more lateral than those of Pax3/7/pax-3 and Zic/ref-2 in C. elegans Third, we show that Msx/vab-15 regulates the development of mechanosensory neurons derived from lateral neural progenitors in multiple invertebrate species, including C. elegans, Drosophila melanogaster, and Ciona intestinalis We also identify a novel lateral neural border specifier, ZNF703/tlp-1, which functions synergistically with Msx/vab-15 in both C. elegans and Xenopus laevis These data suggest a common origin of the molecular mechanism specifying lateral neural borders across bilaterians.
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16
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Kusakabe TG. Identifying Vertebrate Brain Prototypes in Deuterostomes. DIVERSITY AND COMMONALITY IN ANIMALS 2017. [DOI: 10.1007/978-4-431-56469-0_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Leung AW, Murdoch B, Salem AF, Prasad MS, Gomez GA, García-Castro MI. WNT/β-catenin signaling mediates human neural crest induction via a pre-neural border intermediate. Development 2016; 143:398-410. [PMID: 26839343 DOI: 10.1242/dev.130849] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neural crest (NC) cells arise early in vertebrate development, migrate extensively and contribute to a diverse array of ectodermal and mesenchymal derivatives. Previous models of NC formation suggested derivation from neuralized ectoderm, via meso-ectodermal, or neural-non-neural ectoderm interactions. Recent studies using bird and amphibian embryos suggest an earlier origin of NC, independent of neural and mesodermal tissues. Here, we set out to generate a model in which to decipher signaling and tissue interactions involved in human NC induction. Our novel human embryonic stem cell (ESC)-based model yields high proportions of multipotent NC cells (expressing SOX10, PAX7 and TFAP2A) in 5 days. We demonstrate a crucial role for WNT/β-catenin signaling in launching NC development, while blocking placodal and surface ectoderm fates. We provide evidence of the delicate temporal effects of BMP and FGF signaling, and find that NC development is separable from neural and/or mesodermal contributions. We further substantiate the notion of a neural-independent origin of NC through PAX6 expression and knockdown studies. Finally, we identify a novel pre-neural border state characterized by early WNT/β-catenin signaling targets that displays distinct responses to BMP and FGF signaling from the traditional neural border genes. In summary, our work provides a fast and efficient protocol for human NC differentiation under signaling constraints similar to those identified in vivo in model organisms, and strengthens a framework for neural crest ontogeny that is separable from neural and mesodermal fates.
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Affiliation(s)
- Alan W Leung
- Kline Biology Tower, Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA Yale Stem Cell Center, 10 Amistad Street, New Haven, CT 06519, USA
| | - Barbara Murdoch
- Department of Biology, Eastern Connecticut State University, 83 Windham St., Willimantic, CT 06226, USA
| | - Ahmed F Salem
- 203 School of Medicine Research Building, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Maneeshi S Prasad
- 203 School of Medicine Research Building, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Gustavo A Gomez
- 203 School of Medicine Research Building, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
| | - Martín I García-Castro
- Kline Biology Tower, Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue, New Haven, CT 06511, USA 203 School of Medicine Research Building, School of Medicine, University of California Riverside, Riverside, CA 92521, USA
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Kiecker C. WNT Takes Centre Stage in Border Control. EBioMedicine 2015; 2:480-1. [PMID: 26288806 PMCID: PMC4535160 DOI: 10.1016/j.ebiom.2015.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 11/18/2022] Open
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Foxi3 is necessary for the induction of the chick otic placode in response to FGF signaling. Dev Biol 2014; 391:158-69. [PMID: 24780628 DOI: 10.1016/j.ydbio.2014.04.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 03/19/2014] [Accepted: 04/20/2014] [Indexed: 01/06/2023]
Abstract
Vertebrate cranial sensory organs are derived from region at the border of the anterior neural plate called the pre-placodal region (PPR). The otic placode, the anlagen of the inner ear, is induced from PPR ectoderm by FGF signaling. We have previously shown that competence of embryonic ectoderm to respond to FGF signaling during otic placode induction correlates with the expression of PPR genes, but the molecular basis of this competence is poorly understood. Here, we characterize the function of a transcription factor, Foxi3 that is expressed at very early stages in the non-neural ectoderm and later in the PPR of chick embryos. Ablation experiments showed that the underlying hypoblast is necessary for the initiation of Foxi3 expression. Mis-expression of Foxi3 was sufficient to induce markers of non-neural ectoderm such as Dlx5, and the PPR such as Six1 and Eya2. Electroporation of Dlx5, or Six1 together with Eya1 also induced Foxi3, suggesting direct or indirect positive regulation between non-neural ectoderm genes and PPR genes. Knockdown of Foxi3 in chick embryos prevented the induction of otic placode markers, and was able to prevent competent cranial ectoderm from expressing otic markers in response to FGF2. In contrast, Foxi3 expression alone was not sufficient to confer competence to respond to FGF on embryonic ectoderm. Our analysis of PPR and FGF-responsive genes after Foxi3 knockdown at gastrula stages suggests it is not necessary for the expression of PPR genes at these stages, nor for the transduction of FGF signals. The early expression but late requirement for Foxi3 in ear induction suggests it may have some of the properties associated with pioneer transcription factors.
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Schlosser G, Patthey C, Shimeld SM. The evolutionary history of vertebrate cranial placodes II. Evolution of ectodermal patterning. Dev Biol 2014; 389:98-119. [PMID: 24491817 DOI: 10.1016/j.ydbio.2014.01.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 01/21/2014] [Accepted: 01/24/2014] [Indexed: 12/12/2022]
Abstract
Cranial placodes are evolutionary innovations of vertebrates. However, they most likely evolved by redeployment, rewiring and diversification of preexisting cell types and patterning mechanisms. In the second part of this review we compare vertebrates with other animal groups to elucidate the evolutionary history of ectodermal patterning. We show that several transcription factors have ancient bilaterian roles in dorsoventral and anteroposterior regionalisation of the ectoderm. Evidence from amphioxus suggests that ancestral chordates then concentrated neurosecretory cells in the anteriormost non-neural ectoderm. This anterior proto-placodal domain subsequently gave rise to the oral siphon primordia in tunicates (with neurosecretory cells being lost) and anterior (adenohypophyseal, olfactory, and lens) placodes of vertebrates. Likewise, tunicate atrial siphon primordia and posterior (otic, lateral line, and epibranchial) placodes of vertebrates probably evolved from a posterior proto-placodal region in the tunicate-vertebrate ancestor. Since both siphon primordia in tunicates give rise to sparse populations of sensory cells, both proto-placodal domains probably also gave rise to some sensory receptors in the tunicate-vertebrate ancestor. However, proper cranial placodes, which give rise to high density arrays of specialised sensory receptors and neurons, evolved from these domains only in the vertebrate lineage. We propose that this may have involved rewiring of the regulatory network upstream and downstream of Six1/2 and Six4/5 transcription factors and their Eya family cofactors. These proteins, which play ancient roles in neuronal differentiation were first recruited to the dorsal non-neural ectoderm in the tunicate-vertebrate ancestor but subsequently probably acquired new target genes in the vertebrate lineage, allowing them to adopt new functions in regulating proliferation and patterning of neuronal progenitors.
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Affiliation(s)
- Gerhard Schlosser
- Department of Zoology, School of Natural Sciences & Regenerative Medicine Institute (REMEDI), National University of Ireland, University Road, Galway, Ireland.
| | - Cedric Patthey
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Sebastian M Shimeld
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
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Baker CVH, Modrell MS, Gillis JA. The evolution and development of vertebrate lateral line electroreceptors. ACTA ACUST UNITED AC 2014; 216:2515-22. [PMID: 23761476 DOI: 10.1242/jeb.082362] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Electroreception is an ancient vertebrate sense with a fascinating evolutionary history involving multiple losses as well as independent evolution at least twice within teleosts. We review the phylogenetic distribution of electroreception and the morphology and innervation of electroreceptors in different vertebrate groups. We summarise recent work from our laboratory that has confirmed the homology of ampullary electroreceptors in non-teleost jawed vertebrates by showing, in conjunction with previously published work, that these are derived embryonically from lateral line placodes. Finally, we review hypotheses to explain the distribution of electroreception within teleosts, including the hypothesis that teleost ampullary and tuberous electroreceptors evolved via the modification of mechanosensory hair cells in lateral line neuromasts. We conclude that further experimental work on teleost electroreceptor development is needed to test such hypotheses.
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Affiliation(s)
- Clare V H Baker
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
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Setting appropriate boundaries: fate, patterning and competence at the neural plate border. Dev Biol 2013; 389:2-12. [PMID: 24321819 DOI: 10.1016/j.ydbio.2013.11.027] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 11/20/2022]
Abstract
The neural crest and craniofacial placodes are two distinct progenitor populations that arise at the border of the vertebrate neural plate. This border region develops through a series of inductive interactions that begins before gastrulation and progressively divide embryonic ectoderm into neural and non-neural regions, followed by the emergence of neural crest and placodal progenitors. In this review, we describe how a limited repertoire of inductive signals-principally FGFs, Wnts and BMPs-set up domains of transcription factors in the border region which establish these progenitor territories by both cross-inhibitory and cross-autoregulatory interactions. The gradual assembly of different cohorts of transcription factors that results from these interactions is one mechanism to provide the competence to respond to inductive signals in different ways, ultimately generating the neural crest and cranial placodes.
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Yasui K, Kaji T, Morov AR, Yonemura S. Development of oral and branchial muscles in lancelet larvae of Branchiostoma japonicum. J Morphol 2013; 275:465-77. [PMID: 24301696 DOI: 10.1002/jmor.20228] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 10/24/2013] [Accepted: 10/27/2013] [Indexed: 11/12/2022]
Abstract
The perforated pharynx has generally been regarded as a shared characteristic of chordates. However, there still remains phylogenetic ambiguity between the cilia-driven system in invertebrate chordates and the muscle-driven system in vertebrates. Giant larvae of the genus Asymmetron were reported to develop an orobranchial musculature similar to that of vertebrates more than 100 years ago. This discovery might represent an evolutionary link for the chordate branchial system, but few investigations of the lancelet orobranchial musculature have been completed since. We studied staged larvae of a Japanese population of Branchiostoma japonicum to characterize the developmental property of the orobranchial musculature. The larval mouth and the unpaired primary gills develop well-organized muscles. These muscles function only as obturators of the openings without antagonistic system. As the larval mouth enlarged posteriorly to the level of the ninth myomere, the oral musculature was fortified accordingly without segmental patterning. In contrast, the iterated branchial muscles coincided with the dorsal myomeric pattern before metamorphosis, but the pharynx was remodeled dynamically irrespective of the myomeric pattern during metamorphosis. The orobranchial musculature disappeared completely during metamorphosis, and adult muscles in the oral hood and velum, as well as on the pterygial coeloms developed independently. The lancelet orobranchial musculature is apparently a larval adaptation to prevent harmful intake. However, vestigial muscles appeared transiently with the secondary gill formation suggest a bilateral ancestral state of muscular gills, and a segmental pattern of developing branchial muscles without neural crest and placodal contributions is suggestive of a precursor of vertebrate branchiomeric pattern.
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Affiliation(s)
- Kinya Yasui
- Department of Biological Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
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24
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Feinberg TE, Mallatt J. The evolutionary and genetic origins of consciousness in the Cambrian Period over 500 million years ago. Front Psychol 2013; 4:667. [PMID: 24109460 PMCID: PMC3790330 DOI: 10.3389/fpsyg.2013.00667] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 09/05/2013] [Indexed: 11/21/2022] Open
Abstract
Vertebrates evolved in the Cambrian Period before 520 million years ago, but we do not know when or how consciousness arose in the history of the vertebrate brain. Here we propose multiple levels of isomorphic or somatotopic neural representations as an objective marker for sensory consciousness. All extant vertebrates have these, so we deduce that consciousness extends back to the group's origin. The first conscious sense may have been vision. Then vision, coupled with additional sensory systems derived from ectodermal placodes and neural crest, transformed primitive reflexive systems into image forming brains that map and perceive the external world and the body's interior. We posit that the minimum requirement for sensory consciousness and qualia is a brain including a forebrain (but not necessarily a developed cerebral cortex/pallium), midbrain, and hindbrain. This brain must also have (1) hierarchical systems of intercommunicating, isomorphically organized, processing nuclei that extensively integrate the different senses into representations that emerge in upper levels of the neural hierarchy; and (2) a widespread reticular formation that integrates the sensory inputs and contributes to attention, awareness, and neural synchronization. We propose a two-step evolutionary history, in which the optic tectum was the original center of multi-sensory conscious perception (as in fish and amphibians: step 1), followed by a gradual shift of this center to the dorsal pallium or its cerebral cortex (in mammals, reptiles, birds: step 2). We address objections to the hypothesis and call for more studies of fish and amphibians. In our view, the lamprey has all the neural requisites and is likely the simplest extant vertebrate with sensory consciousness and qualia. Genes that pattern the proposed elements of consciousness (isomorphism, neural crest, placodes) have been identified in all vertebrates. Thus, consciousness is in the genes, some of which are already known.
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Affiliation(s)
- Todd E. Feinberg
- Neurology and Psychiatry, Albert Einstein College of Medicine and Beth Israel Medical CenterNew York, NY, USA
| | - Jon Mallatt
- School of Biological Sciences, Washington State UniversityPullman, WA, USA
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Sestak MS, Božičević V, Bakarić R, Dunjko V, Domazet-Lošo T. Phylostratigraphic profiles reveal a deep evolutionary history of the vertebrate head sensory systems. Front Zool 2013; 10:18. [PMID: 23587066 PMCID: PMC3636138 DOI: 10.1186/1742-9994-10-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/11/2013] [Indexed: 12/31/2022] Open
Abstract
Background The vertebrate head is a highly derived trait with a heavy concentration of sophisticated sensory organs that allow complex behaviour in this lineage. The head sensory structures arise during vertebrate development from cranial placodes and the neural crest. It is generally thought that derivatives of these ectodermal embryonic tissues played a central role in the evolutionary transition at the onset of vertebrates. Despite the obvious importance of head sensory organs for vertebrate biology, their evolutionary history is still uncertain. Results To give a fresh perspective on the adaptive history of the vertebrate head sensory organs, we applied genomic phylostratigraphy to large-scale in situ expression data of the developing zebrafish Danio rerio. Contrary to traditional predictions, we found that dominant adaptive signals in the analyzed sensory structures largely precede the evolutionary advent of vertebrates. The leading adaptive signals at the bilaterian-chordate transition suggested that the visual system was the first sensory structure to evolve. The olfactory, vestibuloauditory, and lateral line sensory organs displayed a strong link with the urochordate-vertebrate ancestor. The only structures that qualified as genuine vertebrate innovations were the neural crest derivatives, trigeminal ganglion and adenohypophysis. We also found evidence that the cranial placodes evolved before the neural crest despite their proposed embryological relatedness. Conclusions Taken together, our findings reveal pre-vertebrate roots and a stepwise adaptive history of the vertebrate sensory systems. This study also underscores that large genomic and expression datasets are rich sources of macroevolutionary information that can be recovered by phylostratigraphic mining.
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Affiliation(s)
- Martin Sebastijan Sestak
- Laboratory of Evolutionary Genetics, Ruđer Bošković Institute, Bijenička cesta 54, Zagreb, Croatia.
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Ivashkin E, Adameyko I. Progenitors of the protochordate ocellus as an evolutionary origin of the neural crest. EvoDevo 2013; 4:12. [PMID: 23575111 PMCID: PMC3626940 DOI: 10.1186/2041-9139-4-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 12/28/2012] [Indexed: 01/01/2023] Open
Abstract
The neural crest represents a highly multipotent population of embryonic stem cells found only in vertebrate embryos. Acquisition of the neural crest during the evolution of vertebrates was a great advantage, providing Chordata animals with the first cellular cartilage, bone, dentition, advanced nervous system and other innovations. Today not much is known about the evolutionary origin of neural crest cells. Here we propose a novel scenario in which the neural crest originates from neuroectodermal progenitors of the pigmented ocelli in Amphioxus-like animals. We suggest that because of changes in photoreception needs, these multipotent progenitors of photoreceptors gained the ability to migrate outside of the central nervous system and subsequently started to give rise to neural, glial and pigmented progeny at the periphery.
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Affiliation(s)
- Evgeniy Ivashkin
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles vag 1 A1, Stockholm 17177, Sweden.
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Gasparini F, Degasperi V, Shimeld SM, Burighel P, Manni L. Evolutionary conservation of the placodal transcriptional network during sexual and asexual development in chordates. Dev Dyn 2013; 242:752-66. [DOI: 10.1002/dvdy.23957] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 02/14/2013] [Accepted: 02/15/2013] [Indexed: 01/14/2023] Open
Affiliation(s)
- Fabio Gasparini
- Dipartimento di Biologia; Università degli Studi di Padova; Padova; Italy
| | | | - Sebastian M. Shimeld
- Department of Zoology; University of Oxford; South Parks Road; Oxford; United Kingdom
| | - Paolo Burighel
- Dipartimento di Biologia; Università degli Studi di Padova; Padova; Italy
| | - Lucia Manni
- Dipartimento di Biologia; Università degli Studi di Padova; Padova; Italy
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SONG W, SONG JK. Development of the lateral line system in juvenile Siberian sturgeon ( Acipenser baerii). Zool Res 2013; 33:261-70. [DOI: 10.3724/sp.j.1141.2012.03261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Jidigam VK, Gunhaga L. Development of cranial placodes: insights from studies in chick. Dev Growth Differ 2012; 55:79-95. [PMID: 23278869 DOI: 10.1111/dgd.12027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 11/02/2012] [Accepted: 11/03/2012] [Indexed: 12/19/2022]
Abstract
This review focuses on how research, using chick as a model system, has contributed to our knowledge regarding the development of cranial placodes. This review highlights when and how molecular signaling events regulate early specification of placodal progenitor cells, as well as the development of individual placodes including morphological movements. In addition, we briefly describe various techniques used in chick that are important for studies in cell and developmental biology.
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Affiliation(s)
- Vijay K Jidigam
- Umeå Centre for Molecular Medicine, Umeå University, Umeå, Sweden
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Yardley N, García-Castro MI. FGF signaling transforms non-neural ectoderm into neural crest. Dev Biol 2012; 372:166-77. [PMID: 23000357 PMCID: PMC3541687 DOI: 10.1016/j.ydbio.2012.09.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 07/29/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
Abstract
The neural crest arises at the border between the neural plate and the adjacent non-neural ectoderm. It has been suggested that both neural and non-neural ectoderm can contribute to the neural crest. Several studies have examined the molecular mechanisms that regulate neural crest induction in neuralized tissues or the neural plate border. Here, using the chick as a model system, we address the molecular mechanisms by which non-neural ectoderm generates neural crest. We report that in response to FGF the non-neural ectoderm can ectopically express several early neural crest markers (Pax7, Msx1, Dlx5, Sox9, FoxD3, Snail2, and Sox10). Importantly this response to FGF signaling can occur without inducing ectopic mesodermal tissues. Furthermore, the non-neural ectoderm responds to FGF by expressing the prospective neural marker Sox3, but it does not express definitive markers of neural or anterior neural (Sox2 and Otx2) tissues. These results suggest that the non-neural ectoderm can launch the neural crest program in the absence of mesoderm, without acquiring definitive neural character. Finally, we report that prior to the upregulation of these neural crest markers, the non-neural ectoderm upregulates both BMP and Wnt molecules in response to FGF. Our results provide the first effort to understand the molecular events leading to neural crest development via the non-neural ectoderm in amniotes and present a distinct response to FGF signaling.
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Affiliation(s)
- Nathan Yardley
- KBT 1100, Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208103, New Haven, Connecticut 06520-8103, USA
| | - Martín I. García-Castro
- KBT 1100, Department of Molecular, Cellular, and Developmental Biology, Yale University, PO Box 208103, New Haven, Connecticut 06520-8103, USA
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Forni PE, Wray S. Neural crest and olfactory system: new prospective. Mol Neurobiol 2012; 46:349-60. [PMID: 22773137 PMCID: PMC3586243 DOI: 10.1007/s12035-012-8286-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 05/27/2012] [Indexed: 02/07/2023]
Abstract
Sensory neurons in vertebrates are derived from two embryonic transient cell sources: neural crest (NC) and ectodermal placodes. The placodes are thickenings of ectodermal tissue that are responsible for the formation of cranial ganglia as well as complex sensory organs that include the lens, inner ear, and olfactory epithelium. The NC cells have been indicated to arise at the edges of the neural plate/dorsal neural tube, from both the neural plate and the epidermis in response to reciprocal interactions Moury and Jacobson (Dev Biol 141:243-253, 1990). NC cells migrate throughout the organism and give rise to a multitude of cell types that include melanocytes, cartilage and connective tissue of the head, components of the cranial nerves, the dorsal root ganglia, and Schwann cells. The embryonic definition of these two transient populations and their relative contribution to the formation of sensory organs has been investigated and debated for several decades (Basch and Bronner-Fraser, Adv Exp Med Biol 589:24-31, 2006; Basch et al., Nature 441:218-222, 2006) review (Baker and Bronner-Fraser, Dev Biol 232:1-61, 2001). Historically, all placodes have been described as exclusively derived from non-neural ectodermal progenitors. Recent genetic fate-mapping studies suggested a NC contribution to the olfactory placodes (OP) as well as the otic (auditory) placodes in rodents (Murdoch and Roskams, J Neurosci Off J Soc Neurosci 28:4271-4282, 2008; Murdoch et al., J Neurosci 30:9523-9532, 2010; Forni et al., J Neurosci Off J Soc Neurosci 31:6915-6927, 2011b; Freyer et al., Development 138:5403-5414, 2011; Katoh et al., Mol Brain 4:34, 2011). This review analyzes and discusses some recent developmental studies on the OP, placodal derivatives, and olfactory system.
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Affiliation(s)
- Paolo E. Forni
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Rm. 3A-1012, Bethesda, MD 20892-3703, USA
| | - Susan Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Rm. 3A-1012, Bethesda, MD 20892-3703, USA
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Sato S, Ikeda K, Shioi G, Nakao K, Yajima H, Kawakami K. Regulation of Six1 expression by evolutionarily conserved enhancers in tetrapods. Dev Biol 2012; 368:95-108. [PMID: 22659139 DOI: 10.1016/j.ydbio.2012.05.023] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Revised: 05/16/2012] [Accepted: 05/21/2012] [Indexed: 11/16/2022]
Abstract
The Six1 homeobox gene plays critical roles in vertebrate organogenesis. Mice deficient for Six1 show severe defects in organs such as skeletal muscle, kidney, thymus, sensory organs and ganglia derived from cranial placodes, and mutations in human SIX1 cause branchio-oto-renal syndrome, an autosomal dominant developmental disorder characterized by hearing loss and branchial defects. The present study was designed to identify enhancers responsible for the dynamic expression pattern of Six1 during mouse embryogenesis. The results showed distinct enhancer activities of seven conserved non-coding sequences (CNSs) retained in tetrapod Six1 loci. The activities were detected in all cranial placodes (excluding the lens placode), dorsal root ganglia, somites, nephrogenic cord, notochord and cranial mesoderm. The major Six1-expression domains during development were covered by the sum of activities of these enhancers, together with the previously identified enhancer for the pre-placodal region and foregut endoderm. Thus, the eight CNSs identified in a series of our study represent major evolutionarily conserved enhancers responsible for the expression of Six1 in tetrapods. The results also confirmed that chick electroporation is a robust means to decipher regulatory information stored in vertebrate genomes. Mutational analysis of the most conserved placode-specific enhancer, Six1-21, indicated that the enhancer integrates a variety of inputs from Sox, Pax, Fox, Six, Wnt/Lef1 and basic helix-loop-helix proteins. Positive autoregulation of Six1 is achieved through the regulation of Six protein-binding sites. The identified Six1 enhancers provide valuable tools to understand the mechanism of Six1 regulation and to manipulate gene expression in the developing embryo, particularly in the sensory organs.
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Affiliation(s)
- Shigeru Sato
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
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Olynik BM, Rastegar M. The genetic and epigenetic journey of embryonic stem cells into mature neural cells. Front Genet 2012; 3:81. [PMID: 22629283 PMCID: PMC3355330 DOI: 10.3389/fgene.2012.00081] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 04/25/2012] [Indexed: 12/14/2022] Open
Abstract
Epigenetic changes occur throughout life from embryonic development into adulthood. This results in the timely expression of developmentally important genes, determining the morphology and identity of different cell types and tissues within the body. Epigenetics regulate gene expression and cellular morphology through multiple mechanisms without alteration in the underlying DNA sequences. Different epigenetic mechanisms include chromatin condensation, post-translational modification of histone proteins, DNA cytosine marks, and the activity of non-coding RNA molecules. Epigenetics play key roles in development, stem cell differentiation, and have high impact in human disease. In this review, we will discuss our current knowledge about these epigenetic mechanisms, with a focus on histone and DNA marks. We will then talk about the genetics and epigenetics of embryonic stem cell self-renewal and differentiation into neural stem cells, and further into specific neuronal cell types.
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Affiliation(s)
- Brendan M Olynik
- Regenerative Medicine Program, Faculty of Medicine, University of Manitoba Winnipeg, MB, Canada
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Lu TM, Luo YJ, Yu JK. BMP and Delta/Notch signaling control the development of amphioxus epidermal sensory neurons: insights into the evolution of the peripheral sensory system. Development 2012; 139:2020-30. [PMID: 22535413 DOI: 10.1242/dev.073833] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The evolution of the nervous system has been a topic of great interest. To gain more insight into the evolution of the peripheral sensory system, we used the cephalochordate amphioxus. Amphioxus is a basal chordate that has a dorsal central nervous system (CNS) and a peripheral nervous system (PNS) comprising several types of epidermal sensory neurons (ESNs). Here, we show that a proneural basic helix-loop-helix gene (Ash) is co-expressed with the Delta ligand in ESN progenitor cells. Using pharmacological treatments, we demonstrate that Delta/Notch signaling is likely to be involved in the specification of amphioxus ESNs from their neighboring epidermal cells. We also show that BMP signaling functions upstream of Delta/Notch signaling to induce a ventral neurogenic domain. This patterning mechanism is highly similar to that of the peripheral sensory neurons in the protostome and vertebrate model animals, suggesting that they might share the same ancestry. Interestingly, when BMP signaling is globally elevated in amphioxus embryos, the distribution of ESNs expands to the entire epidermal ectoderm. These results suggest that by manipulating BMP signaling levels, a conserved neurogenesis circuit can be initiated at various locations in the epidermal ectoderm to generate peripheral sensory neurons in amphioxus embryos. We hypothesize that during chordate evolution, PNS progenitors might have been polarized to different positions in various chordate lineages owing to differential regulation of BMP signaling in the ectoderm.
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Affiliation(s)
- Tsai-Ming Lu
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
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Janesick A, Shiotsugu J, Taketani M, Blumberg B. RIPPLY3 is a retinoic acid-inducible repressor required for setting the borders of the pre-placodal ectoderm. Development 2012; 139:1213-24. [PMID: 22354841 DOI: 10.1242/dev.071456] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Retinoic acid signaling is a major component of the neural posteriorizing process in vertebrate development. Here, we identify a new role for the retinoic acid receptor (RAR) in the anterior of the embryo, where RAR regulates Fgf8 expression and formation of the pre-placodal ectoderm (PPE). RARα2 signaling induces key pre-placodal genes and establishes the posterolateral borders of the PPE. RAR signaling upregulates two important genes, Tbx1 and Ripply3, during early PPE development. In the absence of RIPPLY3, TBX1 is required for the expression of Fgf8 and hence, PPE formation. In the presence of RIPPLY3, TBX1 acts as a transcriptional repressor, and functions to restrict the positional expression of Fgf8, a key regulator of PPE gene expression. These results establish a novel role for RAR as a regulator of spatial patterning of the PPE through Tbx1 and RIPPLY3. Moreover, we demonstrate that Ripply3, acting downstream of RAR signaling, is a key player in establishing boundaries in the PPE.
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Affiliation(s)
- Amanda Janesick
- Department of Developmental and Cell Biology, 2011 Biological Sciences 3, University of California, Irvine, CA 92697-2300, USA
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Abstract
During early vertebrate development, the embryonic ectoderm becomes subdivided into neural, neural plate border (border) and epidermal regions. The nervous system is derived from the neural and border domains which, respectively, give rise to the central and peripheral nervous systems. To better understand the functional nervous system we need to know how individual neurons are specified and connected. Our understanding of the early development of the peripheral nervous system has been lagging compared to knowledge regarding central nervous system and epidermal cell lineage decision. Recent advances have shown when and how the specification of border cells is initiated. One important insight is that border specification is already initiated at blastula stages, and can be molecularly and temporally distinguished from rostrocaudal regionalisation of the border. From findings in several species, it is clear that Wnt, Bone Morphogenetic Protein and Fibroblast Growth Factor signals play important roles during the specification and regionalisation of the border. In this review, we highlight the individual roles of these signals and compare models of border specification, including a new model that describes how temporal coordination and epistatic interactions of extracellular signals result in the specification and regionalisation of border cells.
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Affiliation(s)
- Cédric Patthey
- Umeå Centre for Molecular Medicine, Building 6M, 4th Floor, Umeå University, S-901 87 Umeå, Sweden
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37
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Beaster-Jones L. Cis-regulation and conserved non-coding elements in amphioxus. Brief Funct Genomics 2012; 11:118-30. [DOI: 10.1093/bfgp/els006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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38
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Betancur P, Sauka-Spengler T, Bronner M. A Sox10 enhancer element common to the otic placode and neural crest is activated by tissue-specific paralogs. Development 2011; 138:3689-98. [PMID: 21775416 DOI: 10.1242/dev.057836] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The otic placode, a specialized region of ectoderm, gives rise to components of the inner ear and shares many characteristics with the neural crest, including expression of the key transcription factor Sox10. Here, we show that in avian embryos, a highly conserved cranial neural crest enhancer, Sox10E2, also controls the onset of Sox10 expression in the otic placode. Interestingly, we show that different combinations of paralogous transcription factors (Sox8, Pea3 and cMyb versus Sox9, Ets1 and cMyb) are required to mediate Sox10E2 activity in the ear and neural crest, respectively. Mutating their binding motifs within Sox10E2 greatly reduces enhancer activity in the ear. Moreover, simultaneous knockdown of Sox8, Pea3 and cMyb eliminates not only the enhancer-driven reporter expression, but also the onset of endogenous Sox10 expression in the ear. Rescue experiments confirm that the specific combination of Myb together with Sox8 and Pea3 is responsible for the onset of Sox10 expression in the otic placode, as opposed to Myb plus Sox9 and Ets1 for neural crest Sox10 expression. Whereas SUMOylation of Sox8 is not required for the initial onset of Sox10 expression, it is necessary for later otic vesicle formation. This new role of Sox8, Pea3 and cMyb in controlling Sox10 expression via a common otic/neural crest enhancer suggests an evolutionarily conserved function for the combination of paralogous transcription factors in these tissues of distinct embryological origin.
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Affiliation(s)
- Paola Betancur
- Division of Biology 139-74, California Institute of Technology, Pasadena, CA 91125, USA
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Burighel P, Caicci F, Manni L. Hair cells in non-vertebrate models: Lower chordates and molluscs. Hear Res 2011; 273:14-24. [DOI: 10.1016/j.heares.2010.03.087] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/11/2010] [Accepted: 03/15/2010] [Indexed: 10/19/2022]
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Roch GJ, Busby ER, Sherwood NM. Evolution of GnRH: diving deeper. Gen Comp Endocrinol 2011; 171:1-16. [PMID: 21185290 DOI: 10.1016/j.ygcen.2010.12.014] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 12/08/2010] [Accepted: 12/10/2010] [Indexed: 12/18/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) plays a central role in vertebrate reproduction. The evolutionary origin of this neuropeptide and its receptor is not obvious, but the advent of genomics makes it possible to examine the roots of GnRH and delve deeper into its ancestral relationships. New peptide sequences identified in invertebrates from annelids to tunicates reveal GnRH-like peptides of 10-12 amino acids. Structural conservation suggests homology between the 15 known invertebrate peptides and the 15 known vertebrate GnRHs. The functions of the invertebrate GnRH-like peptides are not necessarily related to reproduction. We suggest that structurally related families of invertebrate peptides including corazonin and adipokinetic hormone (AKH) form a superfamily of neuropeptides with the GnRH family. GnRH receptors have also been identified in invertebrates from annelids to tunicates suggesting that the origin of GnRH and its receptor extends deep in evolution to the origin of bilaterian animals. To resolve the relationship of invertebrate and vertebrate receptors, we conducted large-scale phylogenetic analysis using maximum likelihood. The data support a superfamily that includes GnRH, AKH and corazonin receptors derived from both published sequences and unpublished gene model predictions. Closely related to the GnRHR superfamily is the vasopressin/oxytocin superfamily of receptors. Phylogenetic analysis suggests a shared ancestry with deep roots. A functional role for GnRH in vertebrates or invertebrates leads to questions about the evolutionary origin of the pituitary. Our analysis suggests a functioning pituitary was the result of genomic duplications in early vertebrates.
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Affiliation(s)
- Graeme J Roch
- Department of Biology, University of Victoria, Victoria, BC, Canada V8W 3N5
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Posnien N, Koniszewski N, Bucher G. Insect Tc-six4 marks a unit with similarity to vertebrate placodes. Dev Biol 2010; 350:208-16. [PMID: 21034730 DOI: 10.1016/j.ydbio.2010.10.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 10/18/2010] [Accepted: 10/19/2010] [Indexed: 11/20/2022]
Abstract
Cranial placodes are specialized ectodermal regions in the developing vertebrate head that give rise to both neural and non-neural cell types of the neuroendocrine system and the sense organs of the visual, olfactory and acoustic systems. The cranial placodes develop from a panplacodal region which is specifically marked by genes of the eyes absent/eya and two "six homeobox" family members (sine oculis/six1 and six4). It had been believed that cranial placodes are evolutionary novelties of vertebrates. However, data from non-vertebrate chordates suggest that placode-like structures evolved in the chordate ancestor already. Here, we identify a morphological structure in the embryonic head of the beetle Tribolium castaneum with placode-like features. It is marked by the orthologs of the panplacodal markers Tc-six4, Tc-eya and Tc-sine oculis/six1 (Tc-six1) and expresses several genes known to be involved in adenohypophyseal placode development in vertebrates. Moreover, it contributes to both epidermal and neural tissues. We identify Tc-six4 as a specific marker for this structure that we term the insect head placode. Finally, we reveal the regulatory gene network of the panplacodal genes Tc-six4, Tc-eya and Tc-six1 and identify them as head epidermis patterning genes. Our finding of a placode-like structure in an insect suggests that a placode precursor was already present in the last common ancestor of bilaterian animals.
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Affiliation(s)
- Nico Posnien
- Center of Molecular Brain Physiology, Georg-August-University Göttingen, Justus-von-Liebig-Weg 11, 37077 Göttingen, Germany
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42
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Caicci F, Degasperi V, Gasparini F, Zaniolo G, Del Favero M, Burighel P, Manni L. Variability of hair cells in the coronal organ of ascidians (Chordata, Tunicata). CAN J ZOOL 2010. [DOI: 10.1139/z10-036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The tunicate ascidians are nonvertebrate chordates that possess mechanoreceptor cells in the coronal organ in the oral siphon, which monitor the incoming water flow. Like vertebrate hair cells, the mechanoreceptor–coronal cells are secondary sensory (axonless) cells accompanied by supporting cells and they exhibit morphological diversities of apical specialisations: they are multiciliate in ascidians of the order Enterogona, whereas they are more complex and possess one or two cilia accompanied by stereovilli, also graded in length, in ascidians of the order Pleurogona. In morphology, embryonic origin, and arrangement, coronal sensory cells closely resemble vertebrate hair cells. We describe here the coronal organs of five ascidians ( Pyura haustor (Stimpson, 1864), Pyura stolonifera (Heller, 1878), Styela gibbsii (Stimpson, 1864), Styela montereyensis (Dall, 1872), and Polyandrocarpa zorritensis (Van Name, 1931)), belonging to Pleurogona, also comprising species of one family (Pyuridae), not yet considered, and thus completing our overview of the order. Each species possesses at least two kinds of secondary sensory cells, some of them characterized by stereovilli graded in length. In some species, the coronal sensory cells exhibit secretory activity; in P. haustor, a mitotic sensory cell has also been found. We compare the coronal organ in both ascidians and with other chordate sensory organs formed of secondary sensory cells, and discuss their possible homologies.
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Affiliation(s)
- Federico Caicci
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Valentina Degasperi
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Fabio Gasparini
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Giovanna Zaniolo
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Marcello Del Favero
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Paolo Burighel
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
| | - Lucia Manni
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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Sato S, Ikeda K, Shioi G, Ochi H, Ogino H, Yajima H, Kawakami K. Conserved expression of mouse Six1 in the pre-placodal region (PPR) and identification of an enhancer for the rostral PPR. Dev Biol 2010; 344:158-71. [PMID: 20471971 DOI: 10.1016/j.ydbio.2010.04.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 04/24/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
All cranial sensory organs and sensory neurons of vertebrates develop from cranial placodes. In chick, amphibians and zebrafish, all placodes originate from a common precursor domain, the pre-placodal region (PPR), marked by the expression of Six1/4 and Eya1/2. However, the PPR has never been described in mammals and the mechanism involved in the formation of PPR is poorly defined. Here, we report the expression of Six1 in the horseshoe-shaped mouse ectoderm surrounding the anterior neural plate in a pattern broadly similar to that of non-mammalian vertebrates. To elucidate the identity of Six1-positive mouse ectoderm, we searched for enhancers responsible for Six1 expression by in vivo enhancer assays. One conserved non-coding sequence, Six1-14, showed specific enhancer activity in the rostral PPR of chick and Xenopus and in the mouse ectoderm. These results strongly suggest the presence of PPR in mouse and that it is conserved in vertebrates. Moreover, we show the importance of the homeodomain protein-binding sites of Six1-14, the Six1 rostral PPR enhancer, for enhancer activity, and that Dlx5, Msx1 and Pax7 are candidate binding factors that regulate the level and area of Six1 expression, and thereby the location of the PPR. Our findings provide critical information and tools to elucidate the molecular mechanism of early sensory development and have implications for the development of sensory precursor/stem cells.
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Affiliation(s)
- Shigeru Sato
- Division of Biology, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
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Kano S. Genomics and Developmental Approaches to an Ascidian Adenohypophysis Primordium. Integr Comp Biol 2010; 50:35-52. [DOI: 10.1093/icb/icq050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Caicci F, Zaniolo G, Burighel P, Degasperi V, Gasparini F, Manni L. Differentiation of papillae and rostral sensory neurons in the larva of the ascidian Botryllus schlosseri (Tunicata). J Comp Neurol 2010; 518:547-66. [PMID: 20020541 DOI: 10.1002/cne.22222] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
During the metamorphosis of tunicate ascidians, the swimming larva uses its three anterior papillae to detect the substrate for settlement, reabsorbs its chordate-like tail, and becomes a sessile oozooid. In view of the crucial role played by the anterior structures and their nerve relations, we applied electron microscopy and immunocytochemistry to study the larva of the colonial ascidian Botryllus schlosseri, following differentiation of the anterior epidermis during late embryogenesis, the larval stage, and the onset of metamorphosis. Rudiments of the papillae appear in the early tail-bud stage as ectodermic protrusions, the apexes of which differentiate into central and peripheral bipolar neurons. Axons fasciculate into two nerves direct to the brain. Distally, the long, rod-like dendritic terminations extend during the larval stage, becoming exposed to sea water. After the larva selects and adheres to the substrate, these neurons retract and regress. Adjacent to the papillae, other scattered neurons insinuate dendrites into the tunic and form the net of rostral trunk epidermal neurons (RTENs) which fasciculate together with the papillary neurons. Our data indicate that the papillae are simple and coniform, the papillary neurons are mechanoreceptors, and the RTENs are chemoreceptors. The interpapillary epidermal area, by means of an apocrine secretion, provides sticky material for temporary adhesion of the larva to the substrate.
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Affiliation(s)
- Federico Caicci
- Dipartimento di Biologia, Università degli Studi di Padova, I-35121 Padova, Italy
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46
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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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Abstract
Source regions for morphogen gradients-organizing regions-can be generated if a local self-enhancing reaction is coupled with a long-ranging reaction that acts antagonistically. Resulting gradients can be translated into patterns of stable gene activities using genes whose products have a positive feedback on the activation on themselves. If several autoregulatory genes compete with each other for activity, cells make an unequivocal choice. Although the signal consists of a smoothly graded distribution, the all-or-nothing response of the cells leads to regions of differently determined cells that are delimited by sharp borders. In some systems, it is not the absolute but the relative level of a gradient that matters. The sequence of head, tentacles, and foot formation in hydra is controlled by a head activation gradient and is an example of this widely used but conceptually rather neglected mode. For subpatterns such as legs and wings, different "compartments" cooperate to produce new signaling substances. Here, morphogen production is restricted to the common borders or where they intersect. The model accounts for the formation of substructures in pairs at the correct positions within the embryo and for the correct orientation and handedness with respect to the main body axes.
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Affiliation(s)
- Hans Meinhardt
- Max-Planck-Institut für Entwicklungsbiologie, Spemannstr. 35, D- 72076 Tübingen.
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Chordate roots of the vertebrate nervous system: expanding the molecular toolkit. Nat Rev Neurosci 2009; 10:736-46. [PMID: 19738625 DOI: 10.1038/nrn2703] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The vertebrate brain is highly complex with millions to billions of neurons. During development, the neural plate border region gives rise to the neural crest, cranial placodes and, in anamniotes, to Rohon-Beard sensory neurons, whereas the boundary region of the midbrain and hindbrain develops organizer properties. Comparisons of developmental gene expression and neuroanatomy between vertebrates and the basal chordate amphioxus, which has only thousands of neurons and lacks a neural crest, most placodes and a midbrain-hindbrain organizer, indicate that these vertebrate features were built on a foundation already present in the ancestral chordate. Recent advances in genomics have provided insights into the elaboration of the molecular toolkit at the invertebrate-vertebrate transition that may have facilitated the evolution of these vertebrate characteristics.
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Plonka PM, Passeron T, Brenner M, Tobin DJ, Shibahara S, Thomas A, Slominski A, Kadekaro AL, Hershkovitz D, Peters E, Nordlund JJ, Abdel-Malek Z, Takeda K, Paus R, Ortonne JP, Hearing VJ, Schallreuter KU. What are melanocytes really doing all day long...? Exp Dermatol 2009; 18:799-819. [PMID: 19659579 PMCID: PMC2792575 DOI: 10.1111/j.1600-0625.2009.00912.x] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Everyone knows and seems to agree that melanocytes are there to generate melanin - an intriguing, but underestimated multipurpose molecule that is capable of doing far more than providing pigment and UV protection to skin (1). What about the cell that generates melanin, then? Is this dendritic, neural crest-derived cell still serving useful (or even important) functions when no-one looks at the pigmentation of our skin and its appendages and when there is essentially no UV exposure? In other words, what do epidermal and hair follicle melanocytes do in their spare time - at night, under your bedcover? How much of the full portfolio of physiological melanocyte functions in mammalian skin has really been elucidated already? Does the presence or absence of melanocytes matter for normal epidermal and/or hair follicle functions (beyond pigmentation and UV protection), and for skin immune responses? Do melanocytes even deserve as much credit for UV protection as conventional wisdom attributes to them? In which interactions do these promiscuous cells engage with their immediate epithelial environment and who is controlling whom? What lessons might be distilled from looking at lower vertebrate melanophores and at extracutaneous melanocytes in the endeavour to reveal the 'secret identity' of melanocytes? The current Controversies feature explores these far too infrequently posed, biologically and clinically important questions. Complementing a companion viewpoint essay on malignant melanocytes (2), this critical re-examination of melanocyte biology provides a cornucopia of old, but under-appreciated concepts and novel ideas on the slowly emerging complexity of physiological melanocyte functions, and delineates important, thought-provoking questions that remain to be definitively answered by future research.
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Affiliation(s)
- P M Plonka
- Department of Biophysics, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, PL-30-387 Kraków, Poland.
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50
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Kaltenbach SL, Yu JK, Holland ND. The origin and migration of the earliest-developing sensory neurons in the peripheral nervous system of amphioxus. Evol Dev 2009; 11:142-51. [DOI: 10.1111/j.1525-142x.2009.00315.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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