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Duan Z, Wang J, Liu S, Xu Q, Chen H, Li C, Hui M, Chen N. Positive selection in cilia-related genes may facilitate deep-sea adaptation of Thermocollonia jamsteci. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175358. [PMID: 39127215 DOI: 10.1016/j.scitotenv.2024.175358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 08/01/2024] [Accepted: 08/05/2024] [Indexed: 08/12/2024]
Abstract
Deep-sea hydrothermal vents are characterized by high hydrostatic pressure, hypoxia, darkness and toxic substances. However, how organisms adapt to such extreme marine ecosystems remain poorly understood. We hypothesize that adaptive evolution plays an essential role in generating novelty for evolutionary adaptation to the deep-sea environment because adaptive evolution has been found to be critical for species origin and evolution. In this project, the chromosome-level genome of the deep-sea hydrothermal vent gastropod T. jamsteci was constructed for the first time to examine molecular mechanisms of its adaptation to the deep-sea environment. The genome size was large (2.54 Gb), ranking at the top of all species in the Vetigastropoda subclass, driven primarily by the bursts of transposable elements (TEs). The transposition of TEs may also trigger chromosomal changes including both inter-chromosomal fusions and intra-chromosomal activities involving chromosome inversions, rearrangements and fusions, as revealed by comparing the genomes of T. jamsteci and its closely related shallow-sea species Gibbula magus. Innovative changes including the expansion of the ABC transporter gene family that may facilitate detoxification, duplication of genes related to endocytosis, immunity, apoptosis, and anti-apoptotic domains that may help T. jamsteci fight against microbial pathogens, were identified. Furthermore, comparative analysis identified positive selection signals in a large number of genes including the hypoxia up-regulated protein 1, which is a chaperone that may promote adaptation of the T. jamsteci to hypoxic deepsea environments, hox2, Rx2, Pax6 and cilia-related genes BBS1, BBS2, BBS9 and RFX4. Notably, because of the critical importance of cilia and IFT in development, positive selection in cilia-related genes may play a critical role in facilitating T. jamsteci to adapt to the high-pressure deep-sea ecosystem. Results from this study thus revealed important molecular clues that may facilitate further research on the adaptation of molluscs to deep-sea hydrothermal vents.
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Affiliation(s)
- Zelin Duan
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Laboratory of Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Jing Wang
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Shuya Liu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China
| | - Qing Xu
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory of Marine Ecology and Environmental Science, Qingdao Marine Science and Technology Center, Qingdao, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443000, China
| | - Hao Chen
- Center of Deep Sea Research, and CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Chaolun Li
- Center of Deep Sea Research, and CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
| | - Min Hui
- Laoshan Laboratory, Qingdao 266237, China; Laboratory of Marine Organism Taxonomy and Phylogeny, Qingdao Key Laboratory of Marine Biodiversity and Conservation, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
| | - Nansheng Chen
- CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laoshan Laboratory, Qingdao 266237, China; Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China; College of Basic Medical Sciences, China Three Gorges University, Yichang 443000, China.
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Leclercq J, Torres-Paz J, Policarpo M, Agnès F, Rétaux S. Evolution of the regulation of developmental gene expression in blind Mexican cavefish. Development 2024; 151:dev202610. [PMID: 39007346 DOI: 10.1242/dev.202610] [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: 12/13/2023] [Accepted: 07/08/2024] [Indexed: 07/16/2024]
Abstract
Developmental evolution and diversification of morphology can arise through changes in the regulation of gene expression or protein-coding sequence. To unravel mechanisms underlying early developmental evolution in cavefish of the species Astyanax mexicanus, we compared transcriptomes of surface-dwelling and blind cave-adapted morphs at the end of gastrulation. Twenty percent of the transcriptome was differentially expressed. Allelic expression ratios in cave X surface hybrids showed that cis-regulatory changes are the quasi-exclusive contributors to inter-morph variations in gene expression. Among a list of 108 genes with change at the cis-regulatory level, we explored the control of expression of rx3, which is a master eye gene. We discovered that cellular rx3 levels are cis-regulated in a cell-autonomous manner, whereas rx3 domain size depends on non-autonomous Wnt and Bmp signalling. These results highlight how uncoupled mechanisms and regulatory modules control developmental gene expression and shape morphological changes. Finally, a transcriptome-wide search for fixed coding mutations and differential exon use suggested that variations in coding sequence have a minor contribution. Thus, during early embryogenesis, changes in gene expression regulation are the main drivers of cavefish developmental evolution.
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Affiliation(s)
- Julien Leclercq
- Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Saclay, 91400 Saclay, France
| | - Jorge Torres-Paz
- Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Saclay, 91400 Saclay, France
| | - Maxime Policarpo
- Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Saclay, 91400 Saclay, France
| | - François Agnès
- Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Saclay, 91400 Saclay, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, CNRS and University Paris-Saclay, 91400 Saclay, France
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3
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Bulk J, Kyrychenko V, Rensinghoff PM, Ghaderi Ardekani Z, Heermann S. Holoprosencephaly with a Special Form of Anophthalmia Result from Experimental Induction of bmp4, Oversaturating BMP Antagonists in Zebrafish. Int J Mol Sci 2023; 24:ijms24098052. [PMID: 37175759 PMCID: PMC10178349 DOI: 10.3390/ijms24098052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/18/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Vision is likely our most prominent sense and a correct development of the eye is at its basis. Early eye development is tightly connected to the development of the forebrain. A single eye field and the prospective telencephalon are situated within the anterior neural plate (ANP). During normal development, both domains are split and consecutively, two optic vesicles and two telencephalic lobes emerge. If this process is hampered, the domains remain condensed at the midline. The resulting developmental disorder is termed holoprosencephaly (HPE). The typical ocular finding associated with intense forms of HPE is cyclopia. However, also anophthalmia and coloboma can be associated with HPE. Here, we report that a correct balance of Bone morphogenetic proteins (BMPs) and their antagonists are important for forebrain and eye field cleavage. Experimental induction of a BMP ligand results in a severe form of HPE showing anophthalmia. We identified a dysmorphic forebrain containing retinal progenitors, which we termed crypt-oculoid. Optic vesicle evagination is impaired due to a loss of rx3 and, consecutively, of cxcr4a. Our data further suggest that the subduction of prospective hypothalamic cells during neurulation and neural keel formation is affected by the induction of a BMP ligand.
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Affiliation(s)
- Johannes Bulk
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany
| | - Valentyn Kyrychenko
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany
| | - Philipp M Rensinghoff
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany
| | - Zahra Ghaderi Ardekani
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany
| | - Stephan Heermann
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany
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4
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Pakari K, Wittbrodt J, Thumberger T. De novo PAM generation to reach initially inaccessible target sites for base editing. Development 2023; 150:286701. [PMID: 36683434 PMCID: PMC10110497 DOI: 10.1242/dev.201115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 12/16/2022] [Indexed: 01/24/2023]
Abstract
Base editing by CRISPR crucially depends on the presence of a protospacer adjacent motif (PAM) at the correct distance from the editing site. Here, we present and validate an efficient one-shot approach termed 'inception' that expands the editing range. This is achieved by sequential, combinatorial base editing: de novo generated synonymous, non-synonymous or intronic PAM sites facilitate subsequent base editing at nucleotide positions that were initially inaccessible, further opening the targeting range of highly precise editing approaches. We demonstrate the applicability of the inception concept in medaka (Oryzias latipes) in three settings: loss of function, by introducing a pre-termination STOP codon in the open reading frame of oca2; locally confined multi-codon changes to generate allelic variants with different phenotypic severity in kcnh6a; and the removal of a splice acceptor site by targeting intronic sequences of rx3. Using sequentially acting base editors in the described combinatorial approach expands the number of accessible target sites by 65% on average. This allows the use of well-established tools with NGG PAM recognition for the establishment of thus far unreachable disease models, for hypomorphic allele studies and for efficient targeted mechanistic investigations in a precise and predictable manner.
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Affiliation(s)
- Kaisa Pakari
- Centre for Organismal Studies Heidelberg (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.,Heidelberg Biosciences International Graduate School (HBIGS), Heidelberg University, Im Neuenheimer Feld 501, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies Heidelberg (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Thomas Thumberger
- Centre for Organismal Studies Heidelberg (COS), Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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5
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Hernández-Bejarano M, Gestri G, Monfries C, Tucker L, Dragomir EI, Bianco IH, Bovolenta P, Wilson SW, Cavodeassi F. Foxd1-dependent induction of a temporal retinal character is required for visual function. Development 2022; 149:285946. [PMID: 36520654 PMCID: PMC9845753 DOI: 10.1242/dev.200938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 11/14/2022] [Indexed: 12/23/2022]
Abstract
Appropriate patterning of the retina during embryonic development is assumed to underlie the establishment of spatially localised specialisations that mediate the perception of specific visual features. For example, in zebrafish, an area involved in high acuity vision (HAA) is thought to be present in the ventro-temporal retina. Here, we show that the interplay of the transcription factor Rx3 with Fibroblast Growth Factor and Hedgehog signals initiates and restricts foxd1 expression to the prospective temporal retina, initiating naso-temporal regionalisation of the retina. Abrogation of Foxd1 results in the loss of temporal and expansion of nasal retinal character, and consequent absence of the HAA. These structural defects correlate with severe visual defects, as assessed in optokinetic and optomotor response assays. In contrast, optokinetic responses are unaffected in the opposite condition, in which nasal retinal character is lost at the expense of expanded temporal character. Our study indicates that the establishment of temporal retinal character during early retinal development is required for the specification of the HAA, and suggests a prominent role of the temporal retina in controlling specific visual functions.
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Affiliation(s)
| | - Gaia Gestri
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK,Authors for correspondence (; )
| | - Clinton Monfries
- St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Lisa Tucker
- St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Elena I. Dragomir
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Isaac H. Bianco
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK,Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, UK
| | - Paola Bovolenta
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid 28049, Spain,CIBER de Enfermedades Raras (CIBERER), Nicolás Cabrera 1, Madrid 28049, Spain
| | - Stephen W. Wilson
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Florencia Cavodeassi
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid 28049, Spain,St George's University of London, Cranmer Terrace, London SW17 0RE, UK,Authors for correspondence (; )
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6
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Agnès F, Torres-Paz J, Michel P, Rétaux S. A 3D molecular map of the cavefish neural plate illuminates eye-field organization and its borders in vertebrates. Development 2022; 149:274971. [DOI: 10.1242/dev.199966] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/18/2022] [Indexed: 01/21/2023]
Abstract
ABSTRACT
The vertebrate retinas originate from a specific anlage in the anterior neural plate called the eye field. Its identity is conferred by a set of ‘eye transcription factors’, whose combinatorial expression has been overlooked. Here, we use the dimorphic teleost Astyanax mexicanus, which develops proper eyes in the wild type and smaller colobomatous eyes in the blind cavefish embryos, to unravel the molecular anatomy of the eye field and its variations within a species. Using a series of markers (rx3, pax6a, cxcr4b, zic1, lhx2, emx3 and nkx2.1a), we draw a comparative 3D expression map at the end of gastrulation/onset of neurulation, which highlights hyper-regionalization of the eye field into sub-territories of distinct sizes, shapes, cell identities and combinatorial gene expression levels along the three body axes. All these features show significant variations in the cavefish natural mutant. We also discover sub-domains within the prospective telencephalon and characterize cell identities at the frontiers of the eye field. We propose putative fates for some of the characterized eye-field subdivisions, and suggest the existence of a trade-off between some subdivisions in the two Astyanax morphs on a micro-evolutionary scale.
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Affiliation(s)
- François Agnès
- Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, CNRS UMR9197, 91190 Gif-sur-Yvette, France
| | - Jorge Torres-Paz
- Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, CNRS UMR9197, 91190 Gif-sur-Yvette, France
| | - Pauline Michel
- Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, CNRS UMR9197, 91190 Gif-sur-Yvette, France
| | - Sylvie Rétaux
- Institut des Neurosciences Paris-Saclay, Université Paris-Saclay, CNRS UMR9197, 91190 Gif-sur-Yvette, France
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7
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Monnot P, Gangatharan G, Baraban M, Pottin K, Cabrera M, Bonnet I, Breau MA. Intertissue mechanical interactions shape the olfactory circuit in zebrafish. EMBO Rep 2022; 23:e52963. [PMID: 34889034 PMCID: PMC8811657 DOI: 10.15252/embr.202152963] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 02/05/2023] Open
Abstract
While the chemical signals guiding neuronal migration and axon elongation have been extensively studied, the influence of mechanical cues on these processes remains poorly studied in vivo. Here, we investigate how mechanical forces exerted by surrounding tissues steer neuronal movements and axon extension during the morphogenesis of the olfactory placode in zebrafish. We mainly focus on the mechanical contribution of the adjacent eye tissue, which develops underneath the placode through extensive evagination and invagination movements. Using quantitative analysis of cell movements and biomechanical manipulations, we show that the developing eye exerts lateral traction forces on the olfactory placode through extracellular matrix, mediating proper morphogenetic movements and axon extension within the placode. Our data shed new light on the key participation of intertissue mechanical interactions in the sculpting of neuronal circuits.
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Affiliation(s)
- Pauline Monnot
- Centre National de la Recherche Scientifique (CNRS)Institut de Biologie Paris‐Seine (IBPS)Developmental Biology LaboratorySorbonne UniversitéParisFrance
- Institut CurieUniversité PSLSorbonne UniversitéCNRS UMR168Laboratoire Physico Chimie CurieParisFrance
- Laboratoire Jean PerrinParisFrance
| | - Girisaran Gangatharan
- Centre National de la Recherche Scientifique (CNRS)Institut de Biologie Paris‐Seine (IBPS)Developmental Biology LaboratorySorbonne UniversitéParisFrance
| | - Marion Baraban
- Centre National de la Recherche Scientifique (CNRS)Institut de Biologie Paris‐Seine (IBPS)Developmental Biology LaboratorySorbonne UniversitéParisFrance
- Laboratoire Jean PerrinParisFrance
| | - Karen Pottin
- Centre National de la Recherche Scientifique (CNRS)Institut de Biologie Paris‐Seine (IBPS)Developmental Biology LaboratorySorbonne UniversitéParisFrance
| | - Melody Cabrera
- Centre National de la Recherche Scientifique (CNRS)Institut de Biologie Paris‐Seine (IBPS)Developmental Biology LaboratorySorbonne UniversitéParisFrance
| | - Isabelle Bonnet
- Institut CurieUniversité PSLSorbonne UniversitéCNRS UMR168Laboratoire Physico Chimie CurieParisFrance
| | - Marie Anne Breau
- Centre National de la Recherche Scientifique (CNRS)Institut de Biologie Paris‐Seine (IBPS)Developmental Biology LaboratorySorbonne UniversitéParisFrance
- Laboratoire Jean PerrinParisFrance
- Institut National de la Santé et de la Recherche Médicale (INSERM)ParisFrance
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Smith SJ, Holley SA. The eye tugs and the nose follows: how inter-tissue adhesion directs olfactory development. EMBO Rep 2022; 23:e54396. [PMID: 34910840 PMCID: PMC8811622 DOI: 10.15252/embr.202154396] [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: 11/25/2021] [Accepted: 12/03/2021] [Indexed: 02/05/2023] Open
Abstract
Embryonic development is a complex process in which cells divide, migrate, and differentiate in a precise spatiotemporal pattern. Cell-cell communication among neighboring cells plays a central role in specifying cell fate and in coordinating development. Embryonic development also relies on physical interaction between cells and coordinated changes in cell shape. A more recently investigated phenomenon is the coupling of development of adjacent tissues via inter-tissue adhesion. In this issue of EMBO Reports, Monnot and colleagues identify a role for inter-tissue adhesion in the development of adjacent sensory organs in the zebrafish. Specifically, eye morphogenesis influences the organ shape and retrograde axon growth in the adjacent olfactory placode via a shared extracellular matrix.
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Affiliation(s)
- Sarah J Smith
- Department of Molecular, Cellular and Developmental BiologyYale UniversityNew HavenCTUSA
| | - Scott A Holley
- Department of Molecular, Cellular and Developmental BiologyYale UniversityNew HavenCTUSA
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Zilova L, Weinhardt V, Tavhelidse T, Schlagheck C, Thumberger T, Wittbrodt J. Fish primary embryonic pluripotent cells assemble into retinal tissue mirroring in vivo early eye development. eLife 2021; 10:e66998. [PMID: 34252023 PMCID: PMC8275126 DOI: 10.7554/elife.66998] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/24/2021] [Indexed: 12/14/2022] Open
Abstract
Organoids derived from pluripotent stem cells promise the solution to current challenges in basic and biomedical research. Mammalian organoids are however limited by long developmental time, variable success, and lack of direct comparison to an in vivo reference. To overcome these limitations and address species-specific cellular organization, we derived organoids from rapidly developing teleosts. We demonstrate how primary embryonic pluripotent cells from medaka and zebrafish efficiently assemble into anterior neural structures, particularly retina. Within 4 days, blastula-stage cell aggregates reproducibly execute key steps of eye development: retinal specification, morphogenesis, and differentiation. The number of aggregated cells and genetic factors crucially impacted upon the concomitant morphological changes that were intriguingly reflecting the in vivo situation. High efficiency and rapid development of fish-derived organoids in combination with advanced genome editing techniques immediately allow addressing aspects of development and disease, and systematic probing of impact of the physical environment on morphogenesis and differentiation.
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Affiliation(s)
- Lucie Zilova
- Centre for Organismal Studies Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Venera Weinhardt
- Centre for Organismal Studies Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Tinatini Tavhelidse
- Centre for Organismal Studies Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Christina Schlagheck
- Centre for Organismal Studies Heidelberg, Heidelberg UniversityHeidelbergGermany
- Heidelberg International Biosciences Graduate School HBIGS and HeiKa Graduate School on “Functional Materials”HeidelbergGermany
| | - Thomas Thumberger
- Centre for Organismal Studies Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Joachim Wittbrodt
- Centre for Organismal Studies Heidelberg, Heidelberg UniversityHeidelbergGermany
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Buono L, Corbacho J, Naranjo S, Almuedo-Castillo M, Moreno-Marmol T, de la Cerda B, Sanabria-Reinoso E, Polvillo R, Díaz-Corrales FJ, Bogdanovic O, Bovolenta P, Martínez-Morales JR. Analysis of gene network bifurcation during optic cup morphogenesis in zebrafish. Nat Commun 2021; 12:3866. [PMID: 34162866 PMCID: PMC8222258 DOI: 10.1038/s41467-021-24169-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 06/03/2021] [Indexed: 01/04/2023] Open
Abstract
Sight depends on the tight cooperation between photoreceptors and pigmented cells, which derive from common progenitors through the bifurcation of a single gene regulatory network into the neural retina (NR) and retinal-pigmented epithelium (RPE) programs. Although genetic studies have identified upstream nodes controlling these networks, their regulatory logic remains poorly investigated. Here, we characterize transcriptome dynamics and chromatin accessibility in segregating NR/RPE populations in zebrafish. We analyze cis-regulatory modules and enriched transcription factor motives to show extensive network redundancy and context-dependent activity. We identify downstream targets, highlighting an early recruitment of desmosomal genes in the flattening RPE and revealing Tead factors as upstream regulators. We investigate the RPE specification network dynamics to uncover an unexpected sequence of transcription factors recruitment, which is conserved in humans. This systematic interrogation of the NR/RPE bifurcation should improve both genetic counseling for eye disorders and hiPSCs-to-RPE differentiation protocols for cell-replacement therapies in degenerative diseases.
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Affiliation(s)
- Lorena Buono
- Centro Andaluz de Biología del Desarrollo-CABD (CSIC/UPO/JA), Seville, Spain
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Seville, Spain
| | - Jorge Corbacho
- Centro Andaluz de Biología del Desarrollo-CABD (CSIC/UPO/JA), Seville, Spain
| | - Silvia Naranjo
- Centro Andaluz de Biología del Desarrollo-CABD (CSIC/UPO/JA), Seville, Spain
| | | | | | - Berta de la Cerda
- Centro Andaluz de Biología Molecular y Medicina Regenerativa-CABIMER (CSIC/US/UPO/JA), Seville, Spain
| | | | - Rocío Polvillo
- Centro Andaluz de Biología del Desarrollo-CABD (CSIC/UPO/JA), Seville, Spain
| | | | - Ozren Bogdanovic
- Genomics and Epigenetics Division, Garvan Institute of Medical Research, Sydney, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Paola Bovolenta
- Centro de Biología Molecular Severo Ochoa (CSIC/UAM), Seville, Spain.
- CIBERER, ISCIII, Madrid, Spain.
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11
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Davis ES, Voss G, Miesfeld JB, Zarate-Sanchez J, Voss SR, Glaser T. The rax homeobox gene is mutated in the eyeless axolotl, Ambystoma mexicanum. Dev Dyn 2021; 250:807-821. [PMID: 32864847 PMCID: PMC8907009 DOI: 10.1002/dvdy.246] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 08/11/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Vertebrate eye formation requires coordinated inductive interactions between different embryonic tissue layers, first described in amphibians. A network of transcription factors and signaling molecules controls these steps, with mutations causing severe ocular, neuronal, and craniofacial defects. In eyeless mutant axolotls, eye morphogenesis arrests at the optic vesicle stage, before lens induction, and development of ventral forebrain structures is disrupted. RESULTS We identified a 5-bp deletion in the rax (retina and anterior neural fold homeobox) gene, which was tightly linked to the recessive eyeless (e) axolotl locus in an F2 cross. This frameshift mutation, in exon 2, truncates RAX protein within the homeodomain (P154fs35X). Quantitative RNA analysis shows that mutant and wild-type rax transcripts are equally abundant in E/e embryos. Translation appears to initiate from dual start codons, via leaky ribosome scanning, a conserved feature among gnathostome RAX proteins. Previous data show rax is expressed in the optic vesicle and diencephalon, deeply conserved among metazoans, and required for eye formation in other species. CONCLUSION The eyeless axolotl mutation is a null allele in the rax homeobox gene, with primary defects in neural ectoderm, including the retinal and hypothalamic primordia.
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Affiliation(s)
- Erik S. Davis
- Department of Cell Biology and Human Anatomy, University of California Davis School of Medicine, Davis, California
| | - Gareth Voss
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, and Ambystoma Genetic Stock Center, University of Kentucky, Lexington, Kentucky
| | - Joel B. Miesfeld
- Department of Cell Biology and Human Anatomy, University of California Davis School of Medicine, Davis, California
| | - Juan Zarate-Sanchez
- Department of Cell Biology and Human Anatomy, University of California Davis School of Medicine, Davis, California
- Davis Senior High School, Davis, California
| | - S. Randal Voss
- Department of Neuroscience, Spinal Cord and Brain Injury Research Center, and Ambystoma Genetic Stock Center, University of Kentucky, Lexington, Kentucky
| | - Tom Glaser
- Department of Cell Biology and Human Anatomy, University of California Davis School of Medicine, Davis, California
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12
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Li Y, Ma H, Chen R, Zhang H, Nakanishi T, Hu J. Maternal Transfer of 2-Ethylhexyl Diphenyl Phosphate Leads to Developmental Toxicity Possibly by Blocking the Retinoic Acid Receptor and Retinoic X Receptor in Japanese Medaka ( Oryzias latipes). ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:5056-5064. [PMID: 33685123 DOI: 10.1021/acs.est.0c06809] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
2-Ethylhexyl diphenyl phosphate (EHDPP) has been detected in wild fish with high concentrations, which may pose a risk in the embryo development considering its potential maternal transfer. In this study, EHDPP was demonstrated to elicit antagonistic activity to medaka retinoic acid receptor (mRAR) and retinoic X receptor (mRXR) with 50% inhibitory concentration of 18 and 36 μM, respectively. After adult female medaka were exposed to EHDPP at 156, 405, and 1161 ng/L for 35 days, the embryonic EHDPP concentrations (364-4824 ng/g lipid weight (lw)) were higher than those in the maternal tissues (15.0-4166 ng/g lw), showing notable maternal transfer. The embryonic concentration of EHDPP decreased limitedly during 1-2 day post-fertilization (dpf, the main developmental window of eye) but then decreased sharply after 2 dpf. The transcript abundance of cyp26a1 was inhibited and subsequent increasing embryonic all-trans RA level was observed in embryos, showing RAR/RXR antagonistic activity. These results may specifically contribute to the increased eye deformity incidences in all exposure groups (up to 8.0%; 51/637) relative to the control (1.0%, 7/733). The response behavior of the larvae to light stimulation was impaired in a dose-dependent manner, demonstrating a vision disorder. Because such developmental toxicities were observed at the environmental level, EHDPP may pose a threat to the survival of wild larvae and therefore a population risk for wild fish.
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Affiliation(s)
- Yu Li
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Haojia Ma
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Ruichao Chen
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Hong Zhang
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
| | - Tsuyoshi Nakanishi
- Laboratory of Hygienic Chemistry and Molecular Toxicology, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Gifu 501-1196, Japan
| | - Jianying Hu
- MOE Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China
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13
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Warren WC, Boggs TE, Borowsky R, Carlson BM, Ferrufino E, Gross JB, Hillier L, Hu Z, Keene AC, Kenzior A, Kowalko JE, Tomlinson C, Kremitzki M, Lemieux ME, Graves-Lindsay T, McGaugh SE, Miller JT, Mommersteeg MTM, Moran RL, Peuß R, Rice ES, Riddle MR, Sifuentes-Romero I, Stanhope BA, Tabin CJ, Thakur S, Yamamoto Y, Rohner N. A chromosome-level genome of Astyanax mexicanus surface fish for comparing population-specific genetic differences contributing to trait evolution. Nat Commun 2021; 12:1447. [PMID: 33664263 PMCID: PMC7933363 DOI: 10.1038/s41467-021-21733-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 02/02/2021] [Indexed: 01/31/2023] Open
Abstract
Identifying the genetic factors that underlie complex traits is central to understanding the mechanistic underpinnings of evolution. Cave-dwelling Astyanax mexicanus populations are well adapted to subterranean life and many populations appear to have evolved troglomorphic traits independently, while the surface-dwelling populations can be used as a proxy for the ancestral form. Here we present a high-resolution, chromosome-level surface fish genome, enabling the first genome-wide comparison between surface fish and cavefish populations. Using this resource, we performed quantitative trait locus (QTL) mapping analyses and found new candidate genes for eye loss such as dusp26. We used CRISPR gene editing in A. mexicanus to confirm the essential role of a gene within an eye size QTL, rx3, in eye formation. We also generated the first genome-wide evaluation of deletion variability across cavefish populations to gain insight into this potential source of cave adaptation. The surface fish genome reference now provides a more complete resource for comparative, functional and genetic studies of drastic trait differences within a species.
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Affiliation(s)
- Wesley C Warren
- Department of Animal Sciences, Institute for Data Science and Informatics, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.
- Department of Surgery, Institute for Data Science and Informatics, Bond Life Sciences Center, University of Missouri, Columbia, MO, USA.
| | - Tyler E Boggs
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA
| | | | - Brian M Carlson
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, KY, USA
| | - Estephany Ferrufino
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, USA
| | - Joshua B Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH, USA
| | - LaDeana Hillier
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Zhilian Hu
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | | | - Johanna E Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, USA
| | - Chad Tomlinson
- McDonnell Genome Institute, Washington University, St Louis, MO, USA
| | - Milinn Kremitzki
- McDonnell Genome Institute, Washington University, St Louis, MO, USA
| | | | | | - Suzanne E McGaugh
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, USA
| | - Jeffrey T Miller
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, USA
| | | | - Rachel L Moran
- Department of Ecology, Evolution, and Behavior, University of Minnesota, Saint Paul, MN, USA
| | - Robert Peuß
- Stowers Institute for Medical Research, Kansas City, MO, USA
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Edward S Rice
- Bond Life Sciences Center, University of Missouri, Columbia, MO, USA
| | - Misty R Riddle
- Genetics Department, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
- Department of Biology, University of Nevada, Reno, NV, USA
| | | | - Bethany A Stanhope
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, USA
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Clifford J Tabin
- Genetics Department, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Sunishka Thakur
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, USA
| | - Yoshiyuki Yamamoto
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Nicolas Rohner
- Stowers Institute for Medical Research, Kansas City, MO, USA.
- Department of Molecular & Integrative Physiology, KU Medical Center, Kansas City, KS, USA.
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14
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Kushawah G, Hernandez-Huertas L, Abugattas-Nuñez del Prado J, Martinez-Morales JR, DeVore ML, Hassan H, Moreno-Sanchez I, Tomas-Gallardo L, Diaz-Moscoso A, Monges DE, Guelfo JR, Theune WC, Brannan EO, Wang W, Corbin TJ, Moran AM, Sánchez Alvarado A, Málaga-Trillo E, Takacs CM, Bazzini AA, Moreno-Mateos MA. CRISPR-Cas13d Induces Efficient mRNA Knockdown in Animal Embryos. Dev Cell 2020; 54:805-817.e7. [DOI: 10.1016/j.devcel.2020.07.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/27/2020] [Accepted: 07/16/2020] [Indexed: 02/08/2023]
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15
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Sifuentes-Romero I, Ferrufino E, Thakur S, Laboissonniere LA, Solomon M, Smith CL, Keene AC, Trimarchi JM, Kowalko JE. Repeated evolution of eye loss in Mexican cavefish: Evidence of similar developmental mechanisms in independently evolved populations. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 334:423-437. [PMID: 32614138 DOI: 10.1002/jez.b.22977] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 05/05/2020] [Accepted: 06/03/2020] [Indexed: 12/21/2022]
Abstract
Evolution in similar environments often leads to convergence of behavioral and anatomical traits. A classic example of convergent trait evolution is the reduced traits that characterize many cave animals: reduction or loss of pigmentation and eyes. While these traits have evolved many times, relatively little is known about whether these traits repeatedly evolve through the same or different molecular and developmental mechanisms. The small freshwater fish, Astyanax mexicanus, provides an opportunity to investigate the repeated evolution of cave traits. A. mexicanus exists as two forms, a sighted, surface-dwelling form and at least 29 populations of a blind, cave-dwelling form that initially develops eyes that subsequently degenerate. We compared eye morphology and the expression of eye regulatory genes in developing surface fish and two independently evolved cavefish populations, Pachón and Molino. We found that many of the previously described molecular and morphological alterations that occur during eye development in Pachón cavefish are also found in Molino cavefish. However, for many of these traits, the Molino cavefish have a less severe phenotype than Pachón cavefish. Further, cave-cave hybrid fish have larger eyes and lenses during early development compared with fish from either parental population, suggesting that some different changes underlie eye loss in these two populations. Together, these data support the hypothesis that these two cavefish populations evolved eye loss independently, yet through some of the same developmental and molecular mechanisms.
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Affiliation(s)
| | - Estephany Ferrufino
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Sunishka Thakur
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | | | - Michael Solomon
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
| | - Courtney L Smith
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, Florida
| | - Jeffrey M Trimarchi
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa
| | - Johanna E Kowalko
- Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, Florida
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16
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Oonuma K, Kusakabe TG. Spatio-temporal regulation of Rx and mitotic patterns shape the eye-cup of the photoreceptor cells in Ciona. Dev Biol 2018; 445:245-255. [PMID: 30502325 DOI: 10.1016/j.ydbio.2018.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/18/2018] [Accepted: 11/18/2018] [Indexed: 10/27/2022]
Abstract
The ascidian larva has a pigmented ocellus comprised of a cup-shaped array of approximately 30 photoreceptor cells, a pigment cell, and three lens cells. Morphological, physiological and molecular evidence has suggested evolutionary kinship between the ascidian larval photoreceptors and vertebrate retinal and/or pineal photoreceptors. Rx, an essential factor for vertebrate photoreceptor development, has also been suggested to be involved in the development of the ascidian photoreceptor cells, but a recent revision of the photoreceptor cell lineage raised a crucial discrepancy between the reported expression patterns of Rx and the cell lineage. Here, we report spatio-temporal expression patterns of Rx at single-cell resolution along with mitotic patterns up to the final division of the photoreceptor-lineage cells in Ciona. The expression of Rx commences in non-photoreceptor a-lineage cells on the right side of the anterior sensory vesicle at the early tailbud stage. At the mid tailbud stage, Rx begins to be expressed in the A-lineage photoreceptor cell progenitors located on the right side of the posterior sensory vesicle. Thus, Rx is specifically but not exclusively expressed in the photoreceptor-lineage cells in the ascidian embryo. Two cis-regulatory modules are shown to be important for the photoreceptor-lineage expression of Rx. The cell division patterns of the photoreceptor-lineage cells rationally explain the generation of the cup-shaped structure of the pigmented ocellus. The present findings demonstrate the complete cell lineage of the ocellus photoreceptor cells and provide a framework elucidating the molecular and cellular mechanisms of photoreceptor development in Ciona.
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Affiliation(s)
- Kouhei Oonuma
- Institute for Integrative Neurobiology and Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan.
| | - Takehiro G Kusakabe
- Institute for Integrative Neurobiology and Department of Biology, Faculty of Science and Engineering, Konan University, Kobe 658-8501, Japan.
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17
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Unraveling the genetic cause of a consanguineous family with unilateral coloboma and retinoschisis: expanding the phenotypic variability of RAX mutations. Sci Rep 2017; 7:9064. [PMID: 28831107 PMCID: PMC5567291 DOI: 10.1038/s41598-017-09276-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 07/25/2017] [Indexed: 01/08/2023] Open
Abstract
Ocular coloboma is a common eye malformation arising from incomplete closure of the human optic fissure during development. Multiple genetic mutations contribute to the disease process, showing extensive genetic heterogeneity and complexity of coloboma spectrum diseases. In this study, we aimed to unravel the genetic cause of a consanguineous family with unilateral coloboma and retinoschisis. The subjects were recruited and underwent specialized ophthalmologic clinical examination. A combination of whole exome sequencing (WES), homozygosity mapping, and comprehensive variant analyses was performed to uncover the causative mutation. Only one homozygous mutation (c.113 T > C, p.I38T) in RAX gene survived our strict variant filtering process, consistent with an autosomal recessive inheritance pattern. This mutation segregated perfectly in the family and is located in a highly conserved functional domain. Crystal structure modeling indicated that I38T affected the protein structure. We describe a patient from a consanguineous Chinese family with unusual coloboma, proven to harbor a novel RAX mutation (c.113 T > C, p.I38T, homozygous), expanding the phenotypic variability of ocular coloboma and RAX mutations.
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18
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Shi D, Tavhelidse T, Thumberger T, Wittbrodt J, Greb T. Bifacial stem cell niches in fish and plants. Curr Opin Genet Dev 2017; 45:28-33. [PMID: 28242480 DOI: 10.1016/j.gde.2017.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/01/2017] [Accepted: 02/07/2017] [Indexed: 12/20/2022]
Abstract
Embryonic development is key for determining the architecture and shape of multicellular bodies. However, most cells are produced postembryonically in, at least partly, differentiated organs. In this regard, organismal growth faces common challenges in coordinating expansion and function of body structures. Here we compare two examples for postembryonic growth processes from two different kingdoms of life to reveal common regulatory principles: lateral growth of plants and the enlargement of the fish retina. In both cases, growth is based on stem cell systems mediating radial growth by a bifacial mode of tissue production. Surprisingly, although being evolutionary distinct, we find similar patterns in regulatory circuits suggesting the existence of preferable solutions to a common developmental problem.
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Affiliation(s)
- Dongbo Shi
- Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Tinatini Tavhelidse
- Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Thomas Thumberger
- Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Thomas Greb
- Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany.
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19
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Orquera DP, de Souza FSJ. Evolution of the Rax family of developmental transcription factors in vertebrates. Mech Dev 2016; 144:163-170. [PMID: 27838261 DOI: 10.1016/j.mod.2016.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 11/01/2016] [Accepted: 11/07/2016] [Indexed: 02/09/2023]
Abstract
Rax proteins comprise a small family of paired-type, homeodomain-containing transcription factors with essential functions in eye and forebrain development. While invertebrates possess only one Rax gene, vertebrates can have several Rax paralogue genes, but the evolutionary history of the members of the family has not been studied in detail. Here, we present a thorough analysis of the evolutionary relationships between vertebrate Rax genes and proteins available in diverse genomic databases. Phylogenetic and synteny analyses indicate that Rax genes went through a duplication in an ancestor of all jawed vertebrates (Gnathostomata), giving rise to the ancestral vertebrate Rax1 and Rax2 genes. This duplication event is likely related to the proposed polyploidisations that occurred during early vertebrate evolution. Subsequent genome-wide duplications in the lineage of ray-finned fish (Actinopterygii) originated new Rax2 paralogues in the genomes of teleosts. In the lobe-finned fish lineage (Sarcopterygii), the N-terminal octapeptide domain of Rax2 was lost in a common ancestor of tetrapods, giving rise to a shorter version of Rax2 in this lineage. Within placental mammals, the Rax2 gene was lost altogether in an ancestor of rodents and lagomorphs (Glires). Finally, we discuss the scientific literature in the light of Rax gene evolution and propose new avenues of research on the function of this important family of transcriptional regulators.
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Affiliation(s)
- Daniela P Orquera
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina
| | - Flávio S J de Souza
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina; Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
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20
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Kraft KF, Massey EM, Kolb D, Walldorf U, Urbach R. Retinal homeobox promotes cell growth, proliferation and survival of mushroom body neuroblasts in the Drosophila brain. Mech Dev 2016; 142:50-61. [PMID: 27455861 DOI: 10.1016/j.mod.2016.07.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/14/2016] [Accepted: 07/18/2016] [Indexed: 12/29/2022]
Abstract
The Drosophila mushroom bodies, centers of olfactory learning and memory in the fly 'forebrain', develop from a set of neural stem cells (neuroblasts) that generate a large number of Kenyon cells (KCs) during sustained cell divisions from embryonic to late pupal stage. We show that retinal homeobox (rx), encoding for an evolutionarily conserved transcription factor, is required for proper development of the mushroom bodies. Throughout development rx is expressed in mushroom body neuroblasts (MBNBs), their ganglion mother cells (MB-GMCs) and young KCs. In the absence of rx function, MBNBs form correctly but exhibit a reduction in cell size and mitotic activity, whereas overexpression of rx increases growth of MBNBs. These data suggest that Rx is involved in the control of MBNB growth and proliferation. Rx also promotes cell cycling of MB-GMCs. Moreover, we show that Rx is important for the survival of MBNBs and Kenyon cells which undergo premature cell death in the absence of rx function. Simultaneous blocking of cell death restores the normal set of MBNBs and part of the KCs, demonstrating that both, impaired proliferation and premature cell death (of MBNBs and KCs) account for the observed defects in mushroom body development. We then show that Rx controls proliferation within the MBNB clones independently of Tailless (Tll) and Prospero (Pros), and does not regulate the expression of other key regulators of MB development, Eyeless (Ey) and Dachshund (Dac). Our data support that the role of Rx in forebrain development is conserved between vertebrates and fly.
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Affiliation(s)
- Karoline F Kraft
- Institute of Genetics, University of Mainz, D-55099 Mainz, Germany
| | - Eva M Massey
- Institute of Genetics, University of Mainz, D-55099 Mainz, Germany
| | - Dieter Kolb
- Institute of Developmental Biology, Saarland University, D-66421 Homburg/Saar, Germany
| | - Uwe Walldorf
- Institute of Developmental Biology, Saarland University, D-66421 Homburg/Saar, Germany
| | - Rolf Urbach
- Institute of Genetics, University of Mainz, D-55099 Mainz, Germany.
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21
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Specification of embryonic stem cell-derived tissues into eye fields by Wnt signaling using rostral diencephalic tissue-inducing culture. Mech Dev 2016; 141:90-99. [PMID: 27151576 DOI: 10.1016/j.mod.2016.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/26/2016] [Accepted: 05/01/2016] [Indexed: 01/13/2023]
Abstract
The eyes are subdivided from the rostral diencephalon in early development. How the neuroectoderm regulates this subdivision, however, is largely unknown. Taking advantage of embryonic stem cell (ESC) culture using a Rax reporter line to monitor rostral diencephalon formation, we found that ESC-derived tissues at day 7 grown in Glasgow Minimum Expression Media (GMEM) containing knockout serum replacement (KSR) exhibited higher levels of expression of axin2, a Wnt target gene, than those grown in chemically defined medium (CDM). Surprisingly, Wnt agonist facilitated eye field-like tissue specification in CDM. In contrast, the addition of Wnt antagonist diminished eye field tissue formation in GMEM+KSR. Furthermore, the morphological formation of the eye tissue anlage, including the optic vesicle, was accompanied by Wnt signaling activation. Additionally, using CDM culture, we developed an efficient method for generating Rax+/Chx10+ retinal progenitors, which could become fully stratified retina. Here we provide a new avenue for exploring the mechanisms of eye field specification in vitro.
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22
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Reis LM, Semina EV. Conserved genetic pathways associated with microphthalmia, anophthalmia, and coloboma. ACTA ACUST UNITED AC 2015; 105:96-113. [PMID: 26046913 DOI: 10.1002/bdrc.21097] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/13/2015] [Indexed: 12/19/2022]
Abstract
The human eye is a complex organ whose development requires extraordinary coordination of developmental processes. The conservation of ocular developmental steps in vertebrates suggests possible common genetic mechanisms. Genetic diseases involving the eye represent a leading cause of blindness in children and adults. During the last decades, there has been an exponential increase in genetic studies of ocular disorders. In this review, we summarize current success in identification of genes responsible for microphthalmia, anophthalmia, and coloboma (MAC) phenotypes, which are associated with early defects in embryonic eye development. Studies in animal models for the orthologous genes identified overlapping phenotypes for most factors, confirming the conservation of their function in vertebrate development. These animal models allow for further investigation of the mechanisms of MAC, integration of various identified genes into common developmental pathways and finally, provide an avenue for the development and testing of therapeutic interventions.
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Affiliation(s)
- Linda M Reis
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Elena V Semina
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Cell Biology Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
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23
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Stemmer M, Thumberger T, Del Sol Keyer M, Wittbrodt J, Mateo JL. CCTop: An Intuitive, Flexible and Reliable CRISPR/Cas9 Target Prediction Tool. PLoS One 2015; 10:e0124633. [PMID: 25909470 PMCID: PMC4409221 DOI: 10.1371/journal.pone.0124633] [Citation(s) in RCA: 625] [Impact Index Per Article: 69.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/17/2015] [Indexed: 12/26/2022] Open
Abstract
Engineering of the CRISPR/Cas9 system has opened a plethora of new opportunities for site-directed mutagenesis and targeted genome modification. Fundamental to this is a stretch of twenty nucleotides at the 5’ end of a guide RNA that provides specificity to the bound Cas9 endonuclease. Since a sequence of twenty nucleotides can occur multiple times in a given genome and some mismatches seem to be accepted by the CRISPR/Cas9 complex, an efficient and reliable in silico selection and evaluation of the targeting site is key prerequisite for the experimental success. Here we present the CRISPR/Cas9 target online predictor (CCTop, http://crispr.cos.uni-heidelberg.de) to overcome limitations of already available tools. CCTop provides an intuitive user interface with reasonable default parameters that can easily be tuned by the user. From a given query sequence, CCTop identifies and ranks all candidate sgRNA target sites according to their off-target quality and displays full documentation. CCTop was experimentally validated for gene inactivation, non-homologous end-joining as well as homology directed repair. Thus, CCTop provides the bench biologist with a tool for the rapid and efficient identification of high quality target sites.
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Affiliation(s)
- Manuel Stemmer
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Thomas Thumberger
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Maria Del Sol Keyer
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Juan L Mateo
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
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24
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Stemmer M, Schuhmacher LN, Foulkes NS, Bertolucci C, Wittbrodt J. Cavefish eye loss in response to an early block in retinal differentiation progression. Development 2015; 142:743-752. [PMID: 25617433 DOI: 10.1242/dev.114629] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The troglomorphic phenotype shared by diverse cave-dwelling animals is regarded as a classical example of convergent evolution. One unresolved question is whether the characteristic eye loss in diverse cave species is based on interference with the same genetic program. Phreatichthys andruzzii, a Somalian cavefish, has evolved under constant conditions in complete darkness and shows severe troglomorphic characteristics, such as complete loss of eyes, pigments and scales. During early embryonic development, a complete eye is formed but is subsequently lost. In Astyanax mexicanus, another blind cavefish, eye loss has been attributed to interference during eye field patterning. To address whether similar pathways have been targeted by evolution independently, we investigated the retinal development of P. andruzzii, studying the expression of marker genes involved in eye patterning, morphogenesis, differentiation and maintenance. In contrast to Astyanax, patterning of the eye field and evagination of the optic vesicles proceeds without obvious deviation. However, the subsequent differentiation of retinal cell types is arrested during generation of the first-born cell type, retinal ganglion cells, which also fail to project correctly to the optic tectum. Eye degeneration in both species is driven by progressive apoptosis. However, it is retinal apoptosis in Phreatichthys that progresses in a wave-like manner and eliminates progenitor cells that fail to differentiate, in contrast to Astyanax, where lens apoptosis appears to serve as a driving force. Thus, evolution has targeted late retinal differentiation events, indicating that there are several ways to discontinue the development and maintenance of an eye.
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Affiliation(s)
- Manuel Stemmer
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
| | | | - Nicholas S Foulkes
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany.,Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Cristiano Bertolucci
- Department of Life Sciences and Biotechnology, University of Ferrara, 44121 Ferrara, Italy
| | - Joachim Wittbrodt
- Centre for Organismal Studies (COS), Heidelberg University, 69120 Heidelberg, Germany
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25
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McGaugh SE, Gross JB, Aken B, Blin M, Borowsky R, Chalopin D, Hinaux H, Jeffery WR, Keene A, Ma L, Minx P, Murphy D, O’Quin KE, Rétaux S, Rohner N, Searle SMJ, Stahl BA, Tabin C, Volff JN, Yoshizawa M, Warren WC. The cavefish genome reveals candidate genes for eye loss. Nat Commun 2014; 5:5307. [PMID: 25329095 PMCID: PMC4218959 DOI: 10.1038/ncomms6307] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
Natural populations subjected to strong environmental selection pressures offer a window into the genetic underpinnings of evolutionary change. Cavefish populations, Astyanax mexicanus (Teleostei: Characiphysi), exhibit repeated, independent evolution for a variety of traits including eye degeneration, pigment loss, increased size and number of taste buds and mechanosensory organs, and shifts in many behavioural traits. Surface and cave forms are interfertile making this system amenable to genetic interrogation; however, lack of a reference genome has hampered efforts to identify genes responsible for changes in cave forms of A. mexicanus. Here we present the first de novo genome assembly for Astyanax mexicanus cavefish, contrast repeat elements to other teleost genomes, identify candidate genes underlying quantitative trait loci (QTL), and assay these candidate genes for potential functional and expression differences. We expect the cavefish genome to advance understanding of the evolutionary process, as well as, analogous human disease including retinal dysfunction.
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Affiliation(s)
- Suzanne E. McGaugh
- The Genome Institute, Washington University, Campus Box 8501, St Louis, Missouri 63108, USA
| | - Joshua B. Gross
- Department of Biological Sciences, University of Cincinnati, 711B Rieveschl Hall, 312 College Drive, Cincinnati, Ohio 45221, USA
| | - Bronwen Aken
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Maryline Blin
- DECA group, Neurobiology and Development Laboratory, CNRS-Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - Richard Borowsky
- Department of Biology, New York University, New York, New York 10003-6688, USA
| | - Domitille Chalopin
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR 5242, UCBL, 46 allée d’Italie, Lyon F-69364, France
| | - Hélène Hinaux
- DECA group, Neurobiology and Development Laboratory, CNRS-Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - William R. Jeffery
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
| | - Alex Keene
- Department of Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Li Ma
- Department of Biology, University of Maryland, College Park, Maryland 20742, USA
| | - Patrick Minx
- The Genome Institute, Washington University, Campus Box 8501, St Louis, Missouri 63108, USA
| | - Daniel Murphy
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SD, UK
| | - Kelly E. O’Quin
- Department of Biology, Centre College, 600 West Walnut St, Danville, Kentucky 40422, USA
| | - Sylvie Rétaux
- DECA group, Neurobiology and Development Laboratory, CNRS-Institut de Neurobiologie Alfred Fessard, 91198 Gif-sur-Yvette, France
| | - Nicolas Rohner
- Harvard Medical School Department of Genetics, 77 Avenue Louis Pasteur; NRB 360, Boston, Massachusetts 02115, USA
| | - Steve M. J. Searle
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Bethany A. Stahl
- Department of Biological Sciences, University of Cincinnati, 711B Rieveschl Hall, 312 College Drive, Cincinnati, Ohio 45221, USA
| | - Cliff Tabin
- Harvard Medical School Department of Genetics, 77 Avenue Louis Pasteur; NRB 360, Boston, Massachusetts 02115, USA
| | - Jean-Nicolas Volff
- Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon, CNRS, UMR 5242, UCBL, 46 allée d’Italie, Lyon F-69364, France
| | - Masato Yoshizawa
- Department of Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Wesley C. Warren
- The Genome Institute, Washington University, Campus Box 8501, St Louis, Missouri 63108, USA
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26
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Yin J, Morrissey ME, Shine L, Kennedy C, Higgins DG, Kennedy BN. Genes and signaling networks regulated during zebrafish optic vesicle morphogenesis. BMC Genomics 2014; 15:825. [PMID: 25266257 PMCID: PMC4190348 DOI: 10.1186/1471-2164-15-825] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 09/24/2014] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The genetic cascades underpinning vertebrate early eye morphogenesis are poorly understood. One gene family essential for eye morphogenesis encodes the retinal homeobox (Rx) transcription factors. Mutations in the human retinal homeobox gene (RAX) can lead to gross morphological phenotypes ranging from microphthalmia to anophthalmia. Zebrafish rx3 null mutants produce a similar striking eyeless phenotype with an associated expanded forebrain. Thus, we used zebrafish rx3-/- mutants as a model to uncover an Rx3-regulated gene network during early eye morphogenesis. RESULTS Rx3-regulated genes were identified using whole transcriptomic sequencing (RNA-seq) of rx3-/- mutants and morphologically wild-type siblings during optic vesicle morphogenesis. A gene co-expression network was then constructed for the Rx3-regulated genes, identifying gene cross-talk during early eye development. Genes highly connected in the network are hub genes, which tend to exhibit higher expression changes between rx3-/- mutants and normal phenotype siblings. Hub genes down-regulated in rx3-/- mutants encompass homeodomain transcription factors and mediators of retinoid-signaling, both associated with eye development and known human eye disorders. In contrast, genes up-regulated in rx3-/- mutants are centered on Wnt signaling pathways, associated with brain development and disorders. The temporal expression pattern of Rx3-regulated genes was further profiled during early development from maternal stage until visual function is fully mature. Rx3-regulated genes exhibited synchronized expression patterns, and a transition of gene expression during the early segmentation stage when Rx3 was highly expressed. Furthermore, most of these deregulated genes are enriched with multiple RAX-binding motif sequences on the gene promoter. CONCLUSIONS Here, we assembled a comprehensive model of Rx3-regulated genes during early eye morphogenesis. Rx3 promotes optic vesicle morphogenesis and represses brain development through a highly correlated and modulated network, exhibiting repression of genes mediating Wnt signaling and concomitant enhanced expression of homeodomain transcription factors and retinoid-signaling genes.
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Affiliation(s)
- Jun Yin
- />UCD Conway Institute, UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4 Ireland
- />Department of Genetics, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Maria E Morrissey
- />UCD Conway Institute, UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4 Ireland
| | - Lisa Shine
- />UCD Conway Institute, UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4 Ireland
| | - Ciarán Kennedy
- />UCD Conway Institute, UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4 Ireland
| | - Desmond G Higgins
- />UCD Conway Institute, UCD School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4 Ireland
| | - Breandán N Kennedy
- />UCD Conway Institute, UCD School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin 4 Ireland
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27
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Zagozewski JL, Zhang Q, Eisenstat DD. Genetic regulation of vertebrate eye development. Clin Genet 2014; 86:453-60. [PMID: 25174583 DOI: 10.1111/cge.12493] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 08/04/2014] [Accepted: 08/20/2014] [Indexed: 01/14/2023]
Abstract
Eye development is a complex and highly regulated process that consists of several overlapping stages: (i) specification then splitting of the eye field from the developing forebrain; (ii) genesis and patterning of the optic vesicle; (iii) regionalization of the optic cup into neural retina and retina pigment epithelium; and (iv) specification and differentiation of all seven retinal cell types that develop from a pool of retinal progenitor cells in a precise temporal and spatial manner: retinal ganglion cells, horizontal cells, cone photoreceptors, amacrine cells, bipolar cells, rod photoreceptors and Müller glia. Genetic regulation of the stages of eye development includes both extrinsic (such as morphogens, growth factors) and intrinsic factors (primarily transcription factors of the homeobox and basic helix-loop helix families). In the following review, we will provide an overview of the stages of eye development highlighting the role of several important transcription factors in both normal developmental processes and in inherited human eye diseases.
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Affiliation(s)
- J L Zagozewski
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
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28
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Sinn R, Peravali R, Heermann S, Wittbrodt J. Differential responsiveness of distinct retinal domains to Atoh7. Mech Dev 2014; 133:218-29. [PMID: 25151399 PMCID: PMC4232737 DOI: 10.1016/j.mod.2014.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/24/2014] [Accepted: 08/11/2014] [Indexed: 02/03/2023]
Abstract
During vertebrate eye development retinal progenitor cells (RPCs) differentiate into all neural cell types of the retina. Retinal ganglion cells (RGCs) represent the first cell type to be generated. For their development, Atoh7, a basic Helix Loop Helix (bHLH) transcription factor is crucial. Atoh7 loss of function results in a massive reduction or even a total loss of RGCs. However, inconsistent results have been obtained in atoh7 gain of function experiments with respect to ganglion cell genesis, implying that the effect of Atoh7 is likely to be dependent on the competence state of the RPC. In this study we addressed the differential susceptibilities of early RPCs to Atoh7 in vivo, using medaka. Unexpectedly, we observed a largely normal development of the dorsal retina, although atoh7 was precociously expressed. However, the development of the retina close to the optic nerve head (part of the ventral retina) was disturbed severely. Photoreceptors were largely absent and the Müller glia cell number was reduced significantly. The majority of cells in this domain were ganglion cells and the abnormal development of this area affected the closure of the optic fissure resulting in coloboma.
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Affiliation(s)
- Rebecca Sinn
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany; Hartmut Hoffmann-Berling International Graduate School (HBIGS), Heidelberg, Germany
| | - Ravindra Peravali
- Institute of Toxicology and Genetics (ITG), Karlsruhe Institute of Technology, Germany
| | - Stephan Heermann
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany; Institute for Anatomy and Cell Biology, Dept. of Molecular Embryology, University Freiburg, Freiburg, Germany
| | - Joachim Wittbrodt
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
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29
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Gill KP, Hewitt AW, Davidson KC, Pébay A, Wong RCB. Methods of Retinal Ganglion Cell Differentiation From Pluripotent Stem Cells. Transl Vis Sci Technol 2014. [DOI: 10.1167/tvst.3.4.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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30
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Gill KP, Hewitt AW, Davidson KC, Pébay A, Wong RCB. Methods of Retinal Ganglion Cell Differentiation From Pluripotent Stem Cells. Transl Vis Sci Technol 2014; 3:7. [PMID: 25774327 DOI: 10.1167/tvst.3.3.7] [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: 02/24/2014] [Accepted: 04/26/2014] [Indexed: 12/22/2022] Open
Abstract
Glaucoma, the worldwide leading cause of irreversible blindness, is characterized by progressive degeneration of the optic nerve and loss of retinal ganglion cells. Research into glaucoma pathogenesis has been hampered by difficulties in isolating and culturing retinal ganglion cells in vitro. However, recent improvements in laboratory techniques have enabled the generation of a variety of mature cell types from pluripotent stem cells, including retinal ganglion cells. Indeed, stem cell-based approaches have the potential to revolutionize the field by providing an unlimited source of cells for replacement therapies and by enabling development of in vitro disease models for drug screening and research. Consequently, research aimed at directing pluripotent stem cells to differentiate into retinal ganglion cells has expanded dramatically during the past decade, resulting in significant advances in technique and efficiency. In this paper, we review the methodology for retinal ganglion cell differentiation from pluripotent stem cells of both mouse and human origin and summarize how these techniques have opened up new avenues for modelling glaucoma. Generation of stem cell-derived retinal ganglion cells will have significant translational values, providing an in vitro platform to study the mechanisms responsible for pathogenesis and for drug screening to improve treatment options, as well as for the development of cell therapies for optic neuropathies such as glaucoma.
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Affiliation(s)
- Katherine P Gill
- Department of Ophthalmology, University of Melbourne, Melbourne East, VIC, Australia
| | - Alex W Hewitt
- Department of Ophthalmology, University of Melbourne, Melbourne East, VIC, Australia
| | - Kathryn C Davidson
- Department of Ophthalmology, University of Melbourne, Melbourne East, VIC, Australia ; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital Melbourne East, VIC, Australia
| | - Alice Pébay
- Department of Ophthalmology, University of Melbourne, Melbourne East, VIC, Australia ; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital Melbourne East, VIC, Australia
| | - Raymond C B Wong
- Department of Ophthalmology, University of Melbourne, Melbourne East, VIC, Australia ; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital Melbourne East, VIC, Australia
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31
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Affiliation(s)
| | | | - Krzysztof Palczewski
- Department of Pharmacology, School of Medicine, Case
Western Reserve University, 2109 Adelbert Road, Cleveland, Ohio 44106-4965,
United States
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32
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Santos-Ledo A, Cavodeassi F, Carreño H, Aijón J, Arévalo R. Ethanol alters gene expression and cell organization during optic vesicle evagination. Neuroscience 2013; 250:493-506. [PMID: 23892006 PMCID: PMC3988994 DOI: 10.1016/j.neuroscience.2013.07.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 06/25/2013] [Accepted: 07/10/2013] [Indexed: 01/12/2023]
Abstract
Ethanol alters eye morphogenesis at early stages of embryogenesis. The expression patterns of some genes important for eye morphogenesis are perturbed. Ethanol is related to alterations in cell morphology. Ethanol interferes with the optic vesicles evagination.
Ethanol has been described as a teratogen in vertebrate development. During early stages of brain formation, ethanol affects the evagination of the optic vesicles, resulting in synophthalmia or cyclopia, phenotypes where the optic vesicles partially or totally fuse. The mechanisms by which ethanol affects the morphogenesis of the optic vesicles are however largely unknown. In this study we make use of in situ hybridization, electron microscopy and immunohistochemistry to show that ethanol has profound effects on cell organization and gene expression during the evagination of the optic vesicles. Exposure to ethanol during early eye development alters the expression patterns of some genes known to be important for eye morphogenesis, such as rx3/1 and six3a. Furthermore, exposure to ethanol interferes with the acquisition of neuroepithelial features by the eye field cells, which is clear at ultrastructual level. Indeed, ethanol disrupts the acquisition of fusiform cellular shapes within the eye field. In addition, tight junctions do not form and retinal progenitors do not properly polarize, as suggested by the mis-localization and down-regulation of zo1. We also show that the ethanol-induced cyclopic phenotype is significantly different to that observed in cyclopic mutants, suggesting a complex effect of ethanol on a variety of targets. Our results show that ethanol not only disrupts the expression pattern of genes involved in retinal morphogenesis, such as rx3 and rx1, but also disrupts the changes in cell polarity that normally occur during eye field splitting. Thus, ethylic teratology seems to be related not only to modifications in gene expression and cell death but also to alterations in cell morphology.
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Affiliation(s)
- A Santos-Ledo
- Departamento de Biología Celular y Patología, IBSAL-Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Spain
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33
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Sinn R, Wittbrodt J. An eye on eye development. Mech Dev 2013; 130:347-58. [PMID: 23684892 DOI: 10.1016/j.mod.2013.05.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 05/04/2013] [Accepted: 05/07/2013] [Indexed: 12/29/2022]
Abstract
The vertebrate eye is composed of both surface ectodermal and neuroectodermal derivatives that evaginate laterally from an epithelial anlage of the forming diencephalon. The retina is composed of a limited number of neuronal and non-neuronal cell types and is seen as a model for the brain with reduced complexity. The eye develops in a stereotypic manner building on evolutionarily conserved molecular networks. Eye formation is initiated at the onset of gastrulation by the determination of the eye field in the anterior neuroectoderm. Homeobox transcription factors, in particular Six3 are crucially involved in the establishment and maintenance of retinal identity. The eye field expands by proliferation as gastrulation proceeds and is initially confined to a single retinal primordium by the differential activity of specifying transcription factors. This central field is subsequently split in response to secreted factors emanating from the ventral midline. Concomitant with medio-lateral patterning at the onset of neurulation, morphogenesis sets in and laterally evaginates the optic vesicle. Strikingly during this process the neuroectoderm in the eye field transiently loses epithelial features and cells migrate individually. In a second morphogenetic event, the vesicle is transformed into the optic cup, concomitant with onset and progression of retinal differentiation. Accompanying optic cup morphogenesis, neural differentiation is initiated from a retinal signalling centre in a stereotypic and species specific manner by secreted signalling factors. Here we will give an overview of key events during vertebrate eye formation and highlight key players in the respective processes.
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Affiliation(s)
- Rebecca Sinn
- Centre for Organismal Studies, COS Heidelberg, University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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34
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Klimova L, Lachova J, Machon O, Sedlacek R, Kozmik Z. Generation of mRx-Cre transgenic mouse line for efficient conditional gene deletion in early retinal progenitors. PLoS One 2013; 8:e63029. [PMID: 23667567 PMCID: PMC3646923 DOI: 10.1371/journal.pone.0063029] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 03/27/2013] [Indexed: 11/18/2022] Open
Abstract
During mouse eye development, all retinal cell types are generated from the population of retina-committed progenitors originating from the neuroepithelium of the optic vesicle. Conditional gene inactivation provides an efficient tool for studying the genetic basis of the developing retina; however, the number of retina-specific Cre lines is limited. Here we report generation of the mRx-Cre BAC transgenic mouse line in which the expression of Cre recombinase is controlled by regulatory sequences of the mouse Rx gene, one of the earliest determinants of retinal development. When mRx-Cre transgenic mice were crossbred with the ROSA26R or ROSA26R-EYFP reporter lines, the Cre activity was observed in the optic sulcus from embryonic day 8.5 onwards and later in all progenitors residing in the neuroepithelium of the optic cup. Our results suggest that mRx-Cre provides a unique tool for functional genetic studies in very early stages of retinal development. Moreover, since eye organogenesis is dependent on the inductive signals between the optic vesicle and head surface ectoderm, the inductive ability of the optic vesicle can be analyzed using mRx-Cre transgenic mice.
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Affiliation(s)
- Lucie Klimova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Genetics and Microbiology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jitka Lachova
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Ondrej Machon
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Radislav Sedlacek
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Zbynek Kozmik
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- * E-mail:
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35
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Gestri G, Link BA, Neuhauss SCF. The visual system of zebrafish and its use to model human ocular diseases. Dev Neurobiol 2012; 72:302-27. [PMID: 21595048 DOI: 10.1002/dneu.20919] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Free swimming zebrafish larvae depend mainly on their sense of vision to evade predation and to catch prey. Hence, there is strong selective pressure on the fast maturation of visual function and indeed the visual system already supports a number of visually driven behaviors in the newly hatched larvae.The ability to exploit the genetic and embryonic accessibility of the zebrafish in combination with a behavioral assessment of visual system function has made the zebrafish a popular model to study vision and its diseases.Here, we review the anatomy, physiology, and development of the zebrafish eye as the basis to relate the contributions of the zebrafish to our understanding of human ocular diseases.
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Affiliation(s)
- Gaia Gestri
- Department of Cell and Developmental Biology, University College, London,UK.
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36
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Muranishi Y, Terada K, Furukawa T. An essential role for Rax in retina and neuroendocrine system development. Dev Growth Differ 2012; 54:341-8. [PMID: 22524605 DOI: 10.1111/j.1440-169x.2012.01337.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In vertebrates, the central nervous system (CNS) develops as a highly hierarchical, patterned organ with a vast diversity of neuronal and glial cell types. The vertebrate retina is developmentally a part of the CNS. Establishment of the vertebrate retina requires a series of developmental steps including specification of the anterior neural plate, evagination of the optic vesicles from the ventral forebrain, and differentiation of cells. The transcription factor RAX is a paired-type homeoprotein that plays a critical role in the eye and forebrain development of vertebrate species. Rax is initially expressed in the anterior neural region of developing mouse embryos, and later in the retina, pituitary gland, hypothalamus, and pineal gland. The targeted deletion of Rax in the mouse results in no eye formation and abnormal forebrain formation. In humans, mutations in the RAX gene lead to anophthalmia and microphthalmia. These observations indicate that RAX plays a pivotal role in the establishment of the retina. In addition, recent studies have reported that retina and pituitary gland tissues can be induced in a culture system from embryonic stem cells, using RAX expression as an indicator of neuronal progenitor cells in the induced tissue, and suggesting that the Rax gene is a key factor in neuronal regeneration. This review highlights the biological functions and molecular mechanisms of RAX in retina, pituitary, hypothalamus, and pineal gland development.
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Affiliation(s)
- Yuki Muranishi
- Department of Developmental Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka, 565-0874, Japan
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37
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Beccari L, Conte I, Cisneros E, Bovolenta P. Sox2-mediated differential activation of Six3.2 contributes to forebrain patterning. Development 2012; 139:151-64. [PMID: 22096077 DOI: 10.1242/dev.067660] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The vertebrate forebrain is patterned during gastrulation into telencephalic, retinal, hypothalamic and diencephalic primordia. Specification of each of these domains requires the concerted activity of combinations of transcription factors (TFs). Paradoxically, some of these factors are widely expressed in the forebrain, which raises the question of how they can mediate regional differences. To address this issue, we focused on the homeobox TF Six3.2. With genomic and functional approaches we demonstrate that, in medaka fish, Six3.2 regulates, in a concentration-dependent manner, telencephalic and retinal specification under the direct control of Sox2. Six3.2 and Sox2 have antagonistic functions in hypothalamic development. These activities are, in part, executed by Foxg1 and Rx3, which seem to be differentially and directly regulated by Six3.2 and Sox2. Together, these data delineate the mechanisms by which Six3.2 diversifies its activity in the forebrain and highlight a novel function for Sox2 as one of the main regulators of anterior forebrain development. They also demonstrate that graded levels of the same TF, probably operating in partially independent transcriptional networks, pattern the vertebrate forebrain along the anterior-posterior axis.
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Affiliation(s)
- Leonardo Beccari
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, c/Nicolas Cabrera 1, Madrid 28049, Spain
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38
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Mongin E, Auer TO, Bourrat F, Gruhl F, Dewar K, Blanchette M, Wittbrodt J, Ettwiller L. Combining computational prediction of cis-regulatory elements with a new enhancer assay to efficiently label neuronal structures in the medaka fish. PLoS One 2011; 6:e19747. [PMID: 21637758 PMCID: PMC3103512 DOI: 10.1371/journal.pone.0019747] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 04/15/2011] [Indexed: 01/12/2023] Open
Abstract
The developing vertebrate nervous system contains a remarkable array of neural cells organized into complex, evolutionarily conserved structures. The labeling of living cells in these structures is key for the understanding of brain development and function, yet the generation of stable lines expressing reporter genes in specific spatio-temporal patterns remains a limiting step. In this study we present a fast and reliable pipeline to efficiently generate a set of stable lines expressing a reporter gene in multiple neuronal structures in the developing nervous system in medaka. The pipeline combines both the accurate computational genome-wide prediction of neuronal specific cis-regulatory modules (CRMs) and a newly developed experimental setup to rapidly obtain transgenic lines in a cost-effective and highly reproducible manner. 95% of the CRMs tested in our experimental setup show enhancer activity in various and numerous neuronal structures belonging to all major brain subdivisions. This pipeline represents a significant step towards the dissection of embryonic neuronal development in vertebrates.
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Affiliation(s)
- Emmanuel Mongin
- McGill Centre for Bioinformatics, McGill University, Montréal, Canada
| | - Thomas O. Auer
- Centre for Organismal Studies COS, University of Heidelberg, Heidelberg, Germany
| | - Franck Bourrat
- MSNC INRA Group, UPR2197 DEPSN Institut Fessard, CNRS, Gif-sur-Yvette, France
| | - Franziska Gruhl
- Centre for Organismal Studies COS, University of Heidelberg, Heidelberg, Germany
| | - Ken Dewar
- McGill University and Genome Quebec Innovation Centre, Montreal, Canada
| | - Mathieu Blanchette
- McGill Centre for Bioinformatics, McGill University, Montréal, Canada
- * E-mail: (MB); (JW); (LE)
| | - Joachim Wittbrodt
- Centre for Organismal Studies COS, University of Heidelberg, Heidelberg, Germany
- Karlsruhe Institute for Technology KIT, Institute for Toxicology and Genetics, Eggenstein-Leopoldshafen, Germany
- * E-mail: (MB); (JW); (LE)
| | - Laurence Ettwiller
- Centre for Organismal Studies COS, University of Heidelberg, Heidelberg, Germany
- * E-mail: (MB); (JW); (LE)
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39
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Martinez-De Luna RI, Kelly LE, El-Hodiri HM. The Retinal Homeobox (Rx) gene is necessary for retinal regeneration. Dev Biol 2011; 353:10-8. [PMID: 21334323 DOI: 10.1016/j.ydbio.2011.02.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 02/04/2011] [Accepted: 02/10/2011] [Indexed: 01/21/2023]
Abstract
The Retinal Homeobox (Rx) gene is essential for vertebrate eye development. Rx function is required for the specification and maintenance of retinal progenitor cells (RPCs). Loss of Rx function leads to a lack of eye development in a variety of species. Here we show that Rx function is also necessary during retinal regeneration. We performed a thorough characterization of retinal regeneration after partial retinal resection in pre-metamorphic Xenopus laevis. We show that after injury the wound is repopulated with retinal progenitor cells (RPCs) that express Rx and other RPC marker genes. We used an shRNA-based approach to specifically silence Rx expression in vivo in tadpoles. We found that loss of Rx function results in impaired retinal regeneration, including defects in the cells that repopulate the wound and the RPE at the wound site. We show that the regeneration defects can be rescued by provision of exogenous Rx. These results demonstrate for the first time that Rx, in addition to being essential during retinal development, also functions during retinal regeneration.
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Affiliation(s)
- Reyna I Martinez-De Luna
- Graduate Program in Molecular, Cellular, and Developmental Biology, College of Biological Sciences, Ohio State University, Columbus, OH, USA
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Abstract
The medaka fish, Oryzias latipes, is an emerging vertebrate model and now has a high quality draft genome and a number of unique mutants. The long history of medaka research in Japan has provided medaka with unique features, which are complementary to other vertebrate models. A large collection of spontaneous mutants collected over a century, the presence of highly polymorphic inbred lines established over decades, and the recently completed genome sequence all give the medaka a big boost. This review focuses on the state of the art in medaka genetics and genomics, such as the first isolation of active transposons in vertebrates, the influence of chromatin structure on sequence variation, fine quantitative trait locus (QTL) analysis, and versatile mutants as human disease models.
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Affiliation(s)
- Hiroyuki Takeda
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan.
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Martinez-de Luna RI, Moose HE, Kelly LE, Nekkalapudi S, El-Hodiri HM. Regulation of retinal homeobox gene transcription by cooperative activity among cis-elements. Gene 2010; 467:13-24. [PMID: 20627122 DOI: 10.1016/j.gene.2010.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/29/2010] [Accepted: 07/06/2010] [Indexed: 12/23/2022]
Abstract
The retinal homeobox (Rx/rax) gene is essential for the development of the eye. Rax is among the earliest genes expressed during eye development, beginning in the prospective eye fields in the anterior neural plate. Additionally Rax expression persists in retinal progenitor cells and in differentiated photoreceptors. We have isolated and characterized a 2.8 kb genomic DNA fragment that regulates expression of Rax in the developing and maturing retina. We have discovered and characterized cis-acting elements that function to specifically control spatial and temporal Rax expression during retinal development. We have found that the regulation of Rax2A promoter activity requires cooperative interactions between positive and negative regulatory elements. Further, a highly conserved genomic element containing SOX, OTX, and POU transcription factor binding sites is necessary but not sufficient for promoter activity in retinal progenitor or stem cells. Finally, a putative binding element for forkhead transcription factors is necessary for promoter activity and can cooperate with other cis-acting elements to drive Rax2A promoter activity.
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Affiliation(s)
- Reyna I Martinez-de Luna
- Graduate Program in Molecular, Cellular, and Developmental Biology, College of Biological Sciences, The Ohio State University, Columbus, OH, USA
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Mazza ME, Pang K, Reitzel AM, Martindale MQ, Finnerty JR. A conserved cluster of three PRD-class homeobox genes (homeobrain, rx and orthopedia) in the Cnidaria and Protostomia. EvoDevo 2010; 1:3. [PMID: 20849646 PMCID: PMC2938728 DOI: 10.1186/2041-9139-1-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 07/05/2010] [Indexed: 01/25/2023] Open
Abstract
Background Homeobox genes are a superclass of transcription factors with diverse developmental regulatory functions, which are found in plants, fungi and animals. In animals, several Antennapedia (ANTP)-class homeobox genes reside in extremely ancient gene clusters (for example, the Hox, ParaHox, and NKL clusters) and the evolution of these clusters has been implicated in the morphological diversification of animal bodyplans. By contrast, similarly ancient gene clusters have not been reported among the other classes of homeobox genes (that is, the LIM, POU, PRD and SIX classes). Results Using a combination of in silico queries and phylogenetic analyses, we found that a cluster of three PRD-class homeobox genes (Homeobrain (hbn), Rax (rx) and Orthopedia (otp)) is present in cnidarians, insects and mollusks (a partial cluster comprising hbn and rx is present in the placozoan Trichoplax adhaerens). We failed to identify this 'HRO' cluster in deuterostomes; in fact, the Homeobrain gene appears to be missing from the chordate genomes we examined, although it is present in hemichordates and echinoderms. To illuminate the ancestral organization and function of this ancient cluster, we mapped the constituent genes against the assembled genome of a model cnidarian, the sea anemone Nematostella vectensis, and characterized their spatiotemporal expression using in situ hybridization. In N. vectensis, these genes reside in a span of 33 kb with the same gene order as previously reported in insects. Comparisons of genomic sequences and expressed sequence tags revealed the presence of alternative transcripts of Nv-otp and two highly unusual protein-coding polymorphisms in the terminal helix of the Nv-rx homeodomain. A population genetic survey revealed the Rx polymorphisms to be widespread in natural populations. During larval development, all three genes are expressed in the ectoderm, in non-overlapping territories along the oral-aboral axis, with distinct temporal expression. Conclusion We report the first evidence for a PRD-class homeobox cluster that appears to have been conserved since the time of the cnidarian-bilaterian ancestor, and possibly even earlier, given the presence of a partial cluster in the placozoan Trichoplax. Very similar clusters comprising these three genes exist in Nematostella and diverse protostomes. Interestingly, in chordates, one member of the ancestral cluster (homeobrain) has apparently been lost, and there is no linkage between rx and orthopedia in any of the vertebrates. In Nematostella, the spatial expression of these three genes along the body column is not colinear with their physical order in the cluster but the temporal expression is, therefore, using the terminology that has been applied to the Hox cluster genes, the HRO cluster would appear to exhibit temporal but not spatial colinearity. It remains to be seen whether the mechanisms responsible for the evolutionary conservation of the HRO cluster are the same mechanisms responsible for cohesion of the Hox cluster and other ANTP-class homeobox clusters that have been widely conserved throughout animal evolution.
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Affiliation(s)
- Maureen E Mazza
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
| | - Kevin Pang
- Kewalo Marine Lab, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui St., Honolulu, HI 96813, USA
| | - Adam M Reitzel
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA.,Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Mark Q Martindale
- Kewalo Marine Lab, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui St., Honolulu, HI 96813, USA
| | - John R Finnerty
- Department of Biology, Boston University, 5 Cummington Street, Boston, MA 02215, USA
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Pan Y, Martinez-De Luna RI, Lou CH, Nekkalapudi S, Kelly LE, Sater AK, El-Hodiri HM. Regulation of photoreceptor gene expression by the retinal homeobox (Rx) gene product. Dev Biol 2010; 339:494-506. [PMID: 20060393 DOI: 10.1016/j.ydbio.2009.12.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 12/04/2009] [Accepted: 12/18/2009] [Indexed: 12/30/2022]
Abstract
The retinal homeobox (Rx) gene product is essential for eye development. However little is known about its molecular function. It has been demonstrated that Rx binds to photoreceptor conserved element (PCE-1), a highly conserved element found in the promoter region of photoreceptor-specific genes such as rhodopsin and red cone opsin. We verify that Rx is co-expressed with rhodopsin and red cone opsin in maturing photoreceptors and demonstrate that Rx binds to the rhodopsin and red cone opsin promoters in vivo. We also find that Rx can cooperate with the Xenopus analogs of Crx and Nrl, otx5b and XLMaf (respectively), to activate a Xenopus opsin promoter-dependent reporter. Finally, we demonstrate that reduction of Rx expression in tadpoles results in decreases in expression of several PCE-1 containing photoreceptor genes, abnormal photoreceptor morphology, and impaired vision. Our data suggests that Rx, in combination with other transcription factors, is necessary for normal photoreceptor gene expression, maintenance, and function. This establishes a direct role for Rx in regulation of genes expressed in a differentiated cell type.
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Affiliation(s)
- Yi Pan
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA
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Brown KE, Keller PJ, Ramialison M, Rembold M, Stelzer EHK, Loosli F, Wittbrodt J. Nlcam modulates midline convergence during anterior neural plate morphogenesis. Dev Biol 2009; 339:14-25. [PMID: 20005219 DOI: 10.1016/j.ydbio.2009.12.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 12/02/2009] [Accepted: 12/03/2009] [Indexed: 01/13/2023]
Abstract
During development, different cell types must undergo distinct morphogenetic programs so that tissues develop the right dimensions in the appropriate place. In early eye morphogenesis, retinal progenitor cells (RPCs) move first towards the midline, before turning around to migrate out into the evaginating optic vesicles. Neighbouring forebrain cells, however, converge rapidly and then remain at the midline. These differential behaviours are regulated by the transcription factor Rx3. Here, we identify a downstream target of Rx3, the Ig-domain protein Nlcam, and characterise its role in regulating cell migration during the initial phase of optic vesicle morphogenesis. Through sophisticated live imaging and comprehensive cell tracking experiments in zebrafish, we show that ectopic expression of Nlcam in RPCs, as is observed in Rx3 mutants, causes enhanced convergence of these cells. Expression levels of Nlcam therefore regulate the migratory properties of RPCs. Our results provide evidence that the two phases of optic vesicle morphogenesis: slowed convergence and outward-directed migration, are under different genetic control. We propose that Nlcam forms part of the guidance machinery directing rapid midline migration of forebrain precursors, where it is normally expressed, and that its ectopic expression upon loss of Rx3 imparts these migratory characteristics upon RPCs.
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Affiliation(s)
- Katherine E Brown
- Developmental Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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Agathocleous M, Harris WA. From Progenitors to Differentiated Cells in the Vertebrate Retina. Annu Rev Cell Dev Biol 2009; 25:45-69. [DOI: 10.1146/annurev.cellbio.042308.113259] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Michalis Agathocleous
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom;
- Gonville and Caius College, University of Cambridge, Cambridge CB2 1TA, United Kingdom;
| | - William A. Harris
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge CB2 3DY, United Kingdom;
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Martinez-Morales JR, Wittbrodt J. Shaping the vertebrate eye. Curr Opin Genet Dev 2009; 19:511-7. [PMID: 19819125 DOI: 10.1016/j.gde.2009.08.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Revised: 07/24/2009] [Accepted: 08/13/2009] [Indexed: 12/11/2022]
Abstract
For over a century, the vertebrate eye has served as a paradigm for organogenesis. It forms through a complex sequence of morphogenetic events, involving the lateral evagination of the optic vesicles and their subsequent folding into the optic cups. Through intensive studies by experimental embryologists, anatomical descriptions of the process were available since many decades. Recent genetic and molecular work has illuminated essential features of the stereotyped cellular behaviour driving eye morphogenesis. The first pieces of the molecular machinery operating in each individual progenitor cell have been identified. These studies now set the groundwork for a system-wide approach towards understanding the cellular and molecular mechanisms involved in shaping the vertebrate eye.
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Fukamachi S, Kinoshita M, Aizawa K, Oda S, Meyer A, Mitani H. Dual control by a single gene of secondary sexual characters and mating preferences in medaka. BMC Biol 2009; 7:64. [PMID: 19788724 PMCID: PMC2761876 DOI: 10.1186/1741-7007-7-64] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 09/29/2009] [Indexed: 12/28/2022] Open
Abstract
Background Animals utilize a wide variety of tactics to attract reproductive partners. Behavioral experiments often indicate an important role for visual cues in fish, but their molecular basis remains almost entirely unknown. Studies on model species (such as zebrafish and medaka) allow investigations into this fundamental question in behavioral and evolutionary biology. Results Through mate-choice experiences using several laboratory strains of various body colors, we successfully identified one medaka mutant (color interfere; ci) that is distinctly unattractive to reproductive partners. This unattractiveness seems to be due to reduced orange pigment cells (xanthophores) in the skin. The ci strain carries a mutation on the somatolactin alpha (SLa) gene, therefore we expected over-expression of SLa to make medaka hyper-attractive. Indeed, extremely strong mating preferences were detected in a choice between the ci and SLa-transgenic (Actb-SLa:GFP) medaka. Intriguingly, however, the strains showed opposite biases; that is, the mutant and transgenic medaka liked to mate with partners from their own strain, similar to becoming sexually isolated. Conclusion This study spotlighted SLa as a novel mate-choice gene in fish. In addition, these results are the first demonstration of a single gene that can pleiotropically and harmoniously change both secondary sexual characters and mating preferences. Although theoretical models have long suggested joint evolution of linked genes on a chromosome, a mutation on a gene-regulatory region (that is, switching on/off of a single gene) might be sufficient to trigger two 'runaway' processes in different directions to promote (sympatric) speciation.
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Affiliation(s)
- Shoji Fukamachi
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany.
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Vitorino M, Jusuf PR, Maurus D, Kimura Y, Higashijima SI, Harris WA. Vsx2 in the zebrafish retina: restricted lineages through derepression. Neural Dev 2009; 4:14. [PMID: 19344499 PMCID: PMC2683830 DOI: 10.1186/1749-8104-4-14] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Accepted: 04/03/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The neurons in the vertebrate retina arise from multipotent retinal progenitor cells (RPCs). It is not clear, however, which progenitors are multipotent or why they are multipotent. RESULTS In this study we show that the homeodomain transcription factor Vsx2 is initially expressed throughout the retinal epithelium, but later it is downregulated in all but a minor population of bipolar cells and all Müller glia. The Vsx2-negative daughters of Vsx2-positive RPCs divide and give rise to all other cell types in the retina. Vsx2 is a repressor whose targets include transcription factors such as Vsx1, which is expressed in the progenitors of distinct non-Vsx2 bipolars, and the basic helix-loop-helix transcription factor Ath5, which restricts the fate of progenitors to retinal ganglion cells, horizontal cells, amacrine cells and photoreceptors fates. Foxn4, expressed in the progenitors of amacrine and horizontal cells, is also negatively regulated by Vsx2. CONCLUSION Our data thus suggest Vsx2-positive RPCs are fully multipotent retinal progenitors and that when Vsx2 is downregulated, Vsx2-negative progenitors escape Vsx2 repression and so are able to express factors that restrict lineage potential.
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Affiliation(s)
- Marta Vitorino
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK.
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The role of Xenopus Rx-L in photoreceptor cell determination. Dev Biol 2009; 327:352-65. [DOI: 10.1016/j.ydbio.2008.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2008] [Revised: 12/02/2008] [Accepted: 12/15/2008] [Indexed: 11/22/2022]
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Cell-autonomous requirement for rx function in the mammalian retina and posterior pituitary. PLoS One 2009; 4:e4513. [PMID: 19229337 PMCID: PMC2641000 DOI: 10.1371/journal.pone.0004513] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 01/08/2009] [Indexed: 11/19/2022] Open
Abstract
Rx is a paired-like homeobox gene that is required for vertebrate eye formation. Mice lacking Rx function do not develop eyes or the posterior pituitary. To determine whether Rx is required cell autonomously in these tissues, we generated embryonic chimeras consisting of wild type and Rx−/− cells. We found that in the eye, Rx-deficient cells cannot participate in the formation of the neuroretina, retina pigment epithelium and the distal part of the optic stalk. In addition, in the ventral forebrain, Rx function is required cell autonomously for the formation of the posterior pituitary. Interestingly, Rx−/− and wild type cells segregate before the morphogenesis of these two tissues begins. Our observations suggest that Rx function is not only required for the morphogenesis of the retina and posterior pituitary, but also prior to morphogenesis, for the sorting out of cells to form distinct fields of retinal/pituitary cells.
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