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Rocha-Martins M. Cell behaviors that pattern developing tissues: the case of the vertebrate nervous system. Curr Top Dev Biol 2023; 159:30-58. [PMID: 38729679 DOI: 10.1016/bs.ctdb.2023.11.003] [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] [Indexed: 05/12/2024]
Abstract
Morphogenesis from cells to tissue gives rise to the complex architectures that make our organs. How cells and their dynamic behavior are translated into functional spatial patterns is only starting to be understood. Recent advances in quantitative imaging revealed that, although highly heterogeneous, cellular behaviors make reproducible tissue patterns. Emerging evidence suggests that mechanisms of cellular coordination, intrinsic variability and plasticity are critical for robust pattern formation. While pattern development shows a high level of fidelity, tissue organization has undergone drastic changes throughout the course of evolution. In addition, alterations in cell behavior, if unregulated, can cause developmental malformations that disrupt function. Therefore, comparative studies of different species and of disease models offer a powerful approach for understanding how novel spatial configurations arise from variations in cell behavior and the fundamentals of successful pattern formation. In this chapter, I dive into the development of the vertebrate nervous system to explore efforts to dissect pattern formation beyond molecules, the emerging core principles and open questions.
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2
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Owen LJ, Rainger J, Bengani H, Kilanowski F, FitzPatrick DR, Papanastasiou AS. Characterization of an eye field-like state during optic vesicle organoid development. Development 2023; 150:dev201432. [PMID: 37306293 PMCID: PMC10445745 DOI: 10.1242/dev.201432] [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: 11/07/2022] [Accepted: 06/02/2023] [Indexed: 06/13/2023]
Abstract
Specification of the eye field (EF) within the neural plate marks the earliest detectable stage of eye development. Experimental evidence, primarily from non-mammalian model systems, indicates that the stable formation of this group of cells requires the activation of a set of key transcription factors. This crucial event is challenging to probe in mammals and, quantitatively, little is known regarding the regulation of the transition of cells to this ocular fate. Using optic vesicle organoids to model the onset of the EF, we generate time-course transcriptomic data allowing us to identify dynamic gene expression programmes that characterize this cellular-state transition. Integrating this with chromatin accessibility data suggests a direct role of canonical EF transcription factors in regulating these gene expression changes, and highlights candidate cis-regulatory elements through which these transcription factors act. Finally, we begin to test a subset of these candidate enhancer elements, within the organoid system, by perturbing the underlying DNA sequence and measuring transcriptomic changes during EF activation.
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Affiliation(s)
- Liusaidh J. Owen
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Jacqueline Rainger
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Hemant Bengani
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Fiona Kilanowski
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - David R. FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Andrew S. Papanastasiou
- MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, UK
- School of Informatics, University of Edinburgh, Edinburgh EH8 9AB, UK
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3
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Adhish M, Manjubala I. Effectiveness of zebrafish models in understanding human diseases-A review of models. Heliyon 2023; 9:e14557. [PMID: 36950605 PMCID: PMC10025926 DOI: 10.1016/j.heliyon.2023.e14557] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 03/01/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
Understanding the detailed mechanism behind every human disease, disorder, defect, and deficiency is a daunting task concerning the clinical diagnostic tools for patients. Hence, a closely resembling living or simulated model is of paramount interest for the development and testing of a probable novel drug for rectifying the conditions pertaining to the various ailments. The animal model that can be easily genetically manipulated to suit the study of the therapeutic motive is an indispensable asset and within the last few decades, the zebrafish models have proven their effectiveness by becoming such potent human disease models with their use being extended to various avenues of research to understand the underlying mechanisms of the diseases. As zebrafish are explored as model animals in understanding the molecular basis and genetics of many diseases owing to the 70% genetic homology between the human and zebrafish genes; new and fascinating facts about the diseases are being surfaced, establishing it as a very powerful tool for upcoming research. These prospective research areas can be explored in the near future using zebrafish as a model. In this review, the effectiveness of the zebrafish as an animal model against several human diseases such as osteoporosis, atrial fibrillation, Noonan syndrome, leukemia, autism spectrum disorders, etc. has been discussed.
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4
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CRISPR-Cas9 F0 knockout approach using predesigned in vitro transcribed guide RNAs partially recapitulates Rx3 function in eye morphogenesis. J Genet 2022. [DOI: 10.1007/s12041-022-01408-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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5
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Diacou R, Nandigrami P, Fiser A, Liu W, Ashery-Padan R, Cvekl A. Cell fate decisions, transcription factors and signaling during early retinal development. Prog Retin Eye Res 2022; 91:101093. [PMID: 35817658 PMCID: PMC9669153 DOI: 10.1016/j.preteyeres.2022.101093] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/30/2022]
Abstract
The development of the vertebrate eyes is a complex process starting from anterior-posterior and dorso-ventral patterning of the anterior neural tube, resulting in the formation of the eye field. Symmetrical separation of the eye field at the anterior neural plate is followed by two symmetrical evaginations to generate a pair of optic vesicles. Next, reciprocal invagination of the optic vesicles with surface ectoderm-derived lens placodes generates double-layered optic cups. The inner and outer layers of the optic cups develop into the neural retina and retinal pigment epithelium (RPE), respectively. In vitro produced retinal tissues, called retinal organoids, are formed from human pluripotent stem cells, mimicking major steps of retinal differentiation in vivo. This review article summarizes recent progress in our understanding of early eye development, focusing on the formation the eye field, optic vesicles, and early optic cups. Recent single-cell transcriptomic studies are integrated with classical in vivo genetic and functional studies to uncover a range of cellular mechanisms underlying early eye development. The functions of signal transduction pathways and lineage-specific DNA-binding transcription factors are dissected to explain cell-specific regulatory mechanisms underlying cell fate determination during early eye development. The functions of homeodomain (HD) transcription factors Otx2, Pax6, Lhx2, Six3 and Six6, which are required for early eye development, are discussed in detail. Comprehensive understanding of the mechanisms of early eye development provides insight into the molecular and cellular basis of developmental ocular anomalies, such as optic cup coloboma. Lastly, modeling human development and inherited retinal diseases using stem cell-derived retinal organoids generates opportunities to discover novel therapies for retinal diseases.
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Affiliation(s)
- Raven Diacou
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Prithviraj Nandigrami
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andras Fiser
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ales Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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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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White RJ, Mackay E, Wilson SW, Busch-Nentwich EM. Allele-specific gene expression can underlie altered transcript abundance in zebrafish mutants. eLife 2022; 11:72825. [PMID: 35175196 PMCID: PMC8884726 DOI: 10.7554/elife.72825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
In model organisms, RNA-sequencing (RNA-seq) is frequently used to assess the effect of genetic mutations on cellular and developmental processes. Typically, animals heterozygous for a mutation are crossed to produce offspring with different genotypes. Resultant embryos are grouped by genotype to compare homozygous mutant embryos to heterozygous and wild-type siblings. Genes that are differentially expressed between the groups are assumed to reveal insights into the pathways affected by the mutation. Here we show that in zebrafish, differentially expressed genes are often over-represented on the same chromosome as the mutation due to different levels of expression of alleles from different genetic backgrounds. Using an incross of haplotype-resolved wild-type fish, we found evidence of widespread allele-specific expression, which appears as differential expression when comparing embryos homozygous for a region of the genome to their siblings. When analysing mutant transcriptomes, this means that the differential expression of genes on the same chromosome as a mutation of interest may not be caused by that mutation. Typically, the genomic location of a differentially expressed gene is not considered when interpreting its importance with respect to the phenotype. This could lead to pathways being erroneously implicated or overlooked due to the noise of spurious differentially expressed genes on the same chromosome as the mutation. These observations have implications for the interpretation of RNA-seq experiments involving outbred animals and non-inbred model organisms.
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Affiliation(s)
- Richard J White
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Eirinn Mackay
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Elisabeth M Busch-Nentwich
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Department of Medicine, University of Cambridge, Cambridge, United Kingdom.,School of Biological and Behavioural Sciences, Faculty of Science and Engineering, Queen Mary University of London, London, United Kingdom
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8
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Devos L, Agnès F, Edouard J, Simon V, Legendre L, El Khallouki N, Barbachou S, Sohm F, Rétaux S. Eye morphogenesis in the blind Mexican cavefish. Biol Open 2021; 10:bio059031. [PMID: 34590124 PMCID: PMC8565469 DOI: 10.1242/bio.059031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 09/24/2021] [Indexed: 01/13/2023] Open
Abstract
The morphogenesis of the vertebrate eye consists of a complex choreography of cell movements, tightly coupled to axial regionalization and cell type specification processes. Disturbances in these events can lead to developmental defects and blindness. Here, we have deciphered the sequence of defective events leading to coloboma in the embryonic eye of the blind cavefish of the species Astyanax mexicanus. Using comparative live imaging on targeted enhancer-trap Zic1:hsp70:GFP reporter lines of both the normal, river-dwelling morph and the cave morph of the species, we identified defects in migratory cell behaviours during evagination that participate in the reduced optic vesicle size in cavefish, without proliferation defect. Further, impaired optic cup invagination shifts the relative position of the lens and contributes to coloboma in cavefish. Based on these results, we propose a developmental scenario to explain the cavefish phenotype and discuss developmental constraints to morphological evolution. The cavefish eye appears as an outstanding natural mutant model to study molecular and cellular processes involved in optic region morphogenesis.
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Affiliation(s)
- Lucie Devos
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
| | - François Agnès
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
| | - Joanne Edouard
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Victor Simon
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Laurent Legendre
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Naima El Khallouki
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Sosthène Barbachou
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Frédéric Sohm
- AMAGEN, CNRS, INRA, Université Paris-Saclay, 91198, Gif sur Yvette, France
| | - Sylvie Rétaux
- Paris-Saclay Institute of Neuroscience, CNRS, Université Paris-Saclay, 91198 Gif sur Yvette, France
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9
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Harding P, Cunha DL, Moosajee M. Animal and cellular models of microphthalmia. THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:2633004021997447. [PMID: 37181112 PMCID: PMC10032472 DOI: 10.1177/2633004021997447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/02/2021] [Indexed: 05/16/2023]
Abstract
Microphthalmia is a rare developmental eye disorder affecting 1 in 7000 births. It is defined as a small (axial length ⩾2 standard deviations below the age-adjusted mean) underdeveloped eye, caused by disruption of ocular development through genetic or environmental factors in the first trimester of pregnancy. Clinical phenotypic heterogeneity exists amongst patients with varying levels of severity, and associated ocular and systemic features. Up to 11% of blind children are reported to have microphthalmia, yet currently no treatments are available. By identifying the aetiology of microphthalmia and understanding how the mechanisms of eye development are disrupted, we can gain a better understanding of the pathogenesis. Animal models, mainly mouse, zebrafish and Xenopus, have provided extensive information on the genetic regulation of oculogenesis, and how perturbation of these pathways leads to microphthalmia. However, differences exist between species, hence cellular models, such as patient-derived induced pluripotent stem cell (iPSC) optic vesicles, are now being used to provide greater insights into the human disease process. Progress in 3D cellular modelling techniques has enhanced the ability of researchers to study interactions of different cell types during eye development. Through improved molecular knowledge of microphthalmia, preventative or postnatal therapies may be developed, together with establishing genotype-phenotype correlations in order to provide patients with the appropriate prognosis, multidisciplinary care and informed genetic counselling. This review summarises some key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future. Plain language summary Animal and Cellular Models of the Eye Disorder, Microphthalmia (Small Eye) Microphthalmia, meaning a small, underdeveloped eye, is a rare disorder that children are born with. Genetic changes or variations in the environment during the first 3 months of pregnancy can disrupt early development of the eye, resulting in microphthalmia. Up to 11% of blind children have microphthalmia, yet currently no treatments are available. By understanding the genes necessary for eye development, we can determine how disruption by genetic changes or environmental factors can cause this condition. This helps us understand why microphthalmia occurs, and ensure patients are provided with the appropriate clinical care and genetic counselling advice. Additionally, by understanding the causes of microphthalmia, researchers can develop treatments to prevent or reduce the severity of this condition. Animal models, particularly mice, zebrafish and frogs, which can also develop small eyes due to the same genetic/environmental changes, have helped us understand the genes which are important for eye development and can cause birth eye defects when disrupted. Studying a patient's own cells grown in the laboratory can further help researchers understand how changes in genes affect their function. Both animal and cellular models can be used to develop and test new drugs, which could provide treatment options for patients living with microphthalmia. This review summarises the key discoveries from animal and cellular models of microphthalmia and discusses how innovative new models can be used to further our understanding in the future.
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Affiliation(s)
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, 11-43 Bath
Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust,
London, UK
- Great Ormond Street Hospital for Children NHS
Foundation Trust, London, UK
- The Francis Crick Institute, London, UK
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10
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Saiz N, Mora-Bitria L, Rahman S, George H, Herder JP, Garcia-Ojalvo J, Hadjantonakis AK. Growth-factor-mediated coupling between lineage size and cell fate choice underlies robustness of mammalian development. eLife 2020; 9:e56079. [PMID: 32720894 PMCID: PMC7513828 DOI: 10.7554/elife.56079] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 07/24/2020] [Indexed: 01/03/2023] Open
Abstract
Precise control and maintenance of population size is fundamental for organismal development and homeostasis. The three cell types of the mammalian blastocyst are generated in precise proportions over a short time, suggesting a mechanism to ensure a reproducible outcome. We developed a minimal mathematical model demonstrating growth factor signaling is sufficient to guarantee this robustness and which anticipates an embryo's response to perturbations in lineage composition. Addition of lineage-restricted cells both in vivo and in silico, causes a shift of the fate of progenitors away from the supernumerary cell type, while eliminating cells using laser ablation biases the specification of progenitors toward the targeted cell type. Finally, FGF4 couples fate decisions to lineage composition through changes in local growth factor concentration, providing a basis for the regulative abilities of the early mammalian embryo whereby fate decisions are coordinated at the population level to robustly generate tissues in the right proportions.
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Affiliation(s)
- Néstor Saiz
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Laura Mora-Bitria
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, Barcelona, Spain
| | - Shahadat Rahman
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Hannah George
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Jeremy P Herder
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
| | - Jordi Garcia-Ojalvo
- Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona Biomedical Research Park, Barcelona, Spain
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States
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11
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Varga M, Csályi K, Bertyák I, Menyhárd DK, Poole RJ, Cerveny KL, Kövesdi D, Barátki B, Rouse H, Vad Z, Hawkins TA, Stickney HL, Cavodeassi F, Schwarz Q, Young RM, Wilson SW. Tissue-Specific Requirement for the GINS Complex During Zebrafish Development. Front Cell Dev Biol 2020; 8:373. [PMID: 32548116 PMCID: PMC7270345 DOI: 10.3389/fcell.2020.00373] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 04/27/2020] [Indexed: 12/13/2022] Open
Abstract
Efficient and accurate DNA replication is particularly critical in stem and progenitor cells for successful proliferation and survival. The replisome, an amalgam of protein complexes, is responsible for binding potential origins of replication, unwinding the double helix, and then synthesizing complimentary strands of DNA. According to current models, the initial steps of DNA unwinding and opening are facilitated by the CMG complex, which is composed of a GINS heterotetramer that connects Cdc45 with the mini-chromosome maintenance (Mcm) helicase. In this work, we provide evidence that in the absence of GINS function DNA replication is cell autonomously impaired, and we also show that gins1 and gins2 mutants exhibit elevated levels of apoptosis restricted to actively proliferating regions of the central nervous system (CNS). Intriguingly, our results also suggest that the rapid cell cycles during early embryonic development in zebrafish may not require the function of the canonical GINS complex as neither zygotic Gins1 nor Gins2 isoforms seem to be present during these stages.
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Affiliation(s)
- Máté Varga
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary.,Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Kitti Csályi
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - István Bertyák
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dóra K Menyhárd
- HAS-ELTE Protein Modeling Research Group and Laboratory of Structural Chemistry and Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Richard J Poole
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Kara L Cerveny
- Biology Department, Reed College, Portland, OR, United States
| | - Dorottya Kövesdi
- Office of Supported Research Groups of the Hungarian Academy of Sciences, Budapest, Hungary.,Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Balázs Barátki
- Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Hannah Rouse
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Zsuzsa Vad
- Department of Genetics, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Thomas A Hawkins
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Heather L Stickney
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Florencia Cavodeassi
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom.,Institute of Medical and Biomedical Education, St. George's University of London, London, United Kingdom
| | - Quenten Schwarz
- Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, SA, Australia
| | - Rodrigo M Young
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
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12
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Solini GE, Pownall ME, Hillenbrand MJ, Tocheny CE, Paudel S, Halleran AD, Bianchi CH, Huyck RW, Saha MS. Xenopus embryos show a compensatory response following perturbation of the Notch signaling pathway. Dev Biol 2020; 460:99-107. [PMID: 31899211 PMCID: PMC7263880 DOI: 10.1016/j.ydbio.2019.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 12/03/2019] [Accepted: 12/24/2019] [Indexed: 11/09/2022]
Abstract
As an essential feature of development, robustness ensures that embryos attain a consistent phenotype despite genetic and environmental variation. The growing number of examples demonstrating that embryos can mount a compensatory response to germline mutations in key developmental genes has heightened interest in the phenomenon of embryonic robustness. While considerable progress has been made in elucidating genetic compensation in response to germline mutations, the diversity, mechanisms, and limitations of embryonic robustness remain unclear. In this work, we have examined whether Xenopus laevis embryos are able to compensate for perturbations of the Notch signaling pathway induced by RNA injection constructs that either upregulate or inhibit this signaling pathway. Consistent with earlier studies, we found that at neurula stages, hyperactivation of the Notch pathway inhibited neural differentiation while inhibition of Notch signaling increases premature differentiation as assayed by neural beta tubulin expression. However, surprisingly, by hatching stages, embryos begin to compensate for these perturbations, and by swimming tadpole stages most embryos exhibited normal neuronal gene expression. Using cell proliferation and TUNEL assays, we show that the compensatory response is, in part, mediated by modulating levels of cell proliferation and apoptosis. This work provides an additional model for addressing the mechanisms of embryonic robustness and of genetic compensation.
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Affiliation(s)
- Grace E Solini
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Mark E Pownall
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Molly J Hillenbrand
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Claire E Tocheny
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Sudip Paudel
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Andrew D Halleran
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Catherine H Bianchi
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Ryan W Huyck
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Margaret S Saha
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA.
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13
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Young RM, Ewan KB, Ferrer VP, Allende ML, Godovac-Zimmermann J, Dale TC, Wilson SW. Developmentally regulated Tcf7l2 splice variants mediate transcriptional repressor functions during eye formation. eLife 2019; 8:e51447. [PMID: 31829936 PMCID: PMC6908431 DOI: 10.7554/elife.51447] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022] Open
Abstract
Tcf7l2 mediates Wnt/β-Catenin signalling during development and is implicated in cancer and type-2 diabetes. The mechanisms by which Tcf7l2 and Wnt/β-Catenin signalling elicit such a diversity of biological outcomes are poorly understood. Here, we study the function of zebrafish tcf7l2alternative splice variants and show that only variants that include exon five or an analogous human tcf7l2 variant can effectively provide compensatory repressor function to restore eye formation in embryos lacking tcf7l1a/tcf7l1b function. Knockdown of exon five specific tcf7l2 variants in tcf7l1a mutants also compromises eye formation, and these variants can effectively repress Wnt pathway activity in reporter assays using Wnt target gene promoters. We show that the repressive activities of exon5-coded variants are likely explained by their interaction with Tle co-repressors. Furthermore, phosphorylated residues in Tcf7l2 coded exon5 facilitate repressor activity. Our studies suggest that developmentally regulated splicing of tcf7l2 can influence the transcriptional output of the Wnt pathway.
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Affiliation(s)
- Rodrigo M Young
- Department of Cell and Developmental BiologyUCLLondonUnited Kingdom
| | - Kenneth B Ewan
- School of Bioscience, Cardiff UniversityCardiffUnited Kingdom
| | | | - Miguel L Allende
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de ChileSantiagoChile
| | | | - Trevor C Dale
- School of Bioscience, Cardiff UniversityCardiffUnited Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental BiologyUCLLondonUnited Kingdom
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14
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Holt RJ, Young RM, Crespo B, Ceroni F, Curry CJ, Bellacchio E, Bax DA, Ciolfi A, Simon M, Fagerberg CR, van Binsbergen E, De Luca A, Memo L, Dobyns WB, Mohammed AA, Clokie SJ, Zazo Seco C, Jiang YH, Sørensen KP, Andersen H, Sullivan J, Powis Z, Chassevent A, Smith-Hicks C, Petrovski S, Antoniadi T, Shashi V, Gelb BD, Wilson SW, Gerrelli D, Tartaglia M, Chassaing N, Calvas P, Ragge NK. De Novo Missense Variants in FBXW11 Cause Diverse Developmental Phenotypes Including Brain, Eye, and Digit Anomalies. Am J Hum Genet 2019; 105:640-657. [PMID: 31402090 PMCID: PMC6731360 DOI: 10.1016/j.ajhg.2019.07.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/09/2019] [Indexed: 12/20/2022] Open
Abstract
The identification of genetic variants implicated in human developmental disorders has been revolutionized by second-generation sequencing combined with international pooling of cases. Here, we describe seven individuals who have diverse yet overlapping developmental anomalies, and who all have de novo missense FBXW11 variants identified by whole exome or whole genome sequencing and not reported in the gnomAD database. Their phenotypes include striking neurodevelopmental, digital, jaw, and eye anomalies, and in one individual, features resembling Noonan syndrome, a condition caused by dysregulated RAS signaling. FBXW11 encodes an F-box protein, part of the Skp1-cullin-F-box (SCF) ubiquitin ligase complex, involved in ubiquitination and proteasomal degradation and thus fundamental to many protein regulatory processes. FBXW11 targets include β-catenin and GLI transcription factors, key mediators of Wnt and Hh signaling, respectively, critical to digital, neurological, and eye development. Structural analyses indicate affected residues cluster at the surface of the loops of the substrate-binding domain of FBXW11, and the variants are predicted to destabilize the protein and/or its interactions. In situ hybridization studies on human and zebrafish embryonic tissues demonstrate FBXW11 is expressed in the developing eye, brain, mandibular processes, and limb buds or pectoral fins. Knockdown of the zebrafish FBXW11 orthologs fbxw11a and fbxw11b resulted in embryos with smaller, misshapen, and underdeveloped eyes and abnormal jaw and pectoral fin development. Our findings support the role of FBXW11 in multiple developmental processes, including those involving the brain, eye, digits, and jaw.
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15
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Cavodeassi F, Wilson SW. Looking to the future of zebrafish as a model to understand the genetic basis of eye disease. Hum Genet 2019; 138:993-1000. [PMID: 31422478 PMCID: PMC6710215 DOI: 10.1007/s00439-019-02055-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023]
Abstract
In this brief commentary, we provide some of our thoughts and opinions on the current and future use of zebrafish to model human eye disease, dissect pathological progression and advance in our understanding of the genetic bases of microphthalmia, andophthalmia and coloboma (MAC) in humans. We provide some background on eye formation in fish and conservation and divergence across vertebrates in this process, discuss different approaches for manipulating gene function and speculate on future research areas where we think research using fish may prove to be particularly effective.
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Affiliation(s)
- Florencia Cavodeassi
- Institute of Medical and Biomedical Education, St. George's, University of London, Cranmer Terrace, London, SW17 0RE, UK.
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, Biosciences, UCL, Gower St, London, WC1E 6BT, UK
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