1
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Marelli E, Hughes J, Scotting PJ. SUMO-dependent transcriptional repression by Sox2 inhibits the proliferation of neural stem cells. PLoS One 2024; 19:e0298818. [PMID: 38507426 PMCID: PMC10954124 DOI: 10.1371/journal.pone.0298818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 01/30/2024] [Indexed: 03/22/2024] Open
Abstract
Sox2 is known for its roles in maintaining the stem cell state of embryonic stem cells and neural stem cells. In particular, it has been shown to slow the proliferation of these cell types. It is also known for its effects as an activating transcription factor. Despite this, analysis of published studies shows that it represses as many genes as it activates. Here, we identify a new set of target genes that Sox2 represses in neural stem cells. These genes are associated with centrosomes, centromeres and other aspects of cell cycle control. In addition, we show that SUMOylation of Sox2 is necessary for the repression of these genes and for its repressive effects on cell proliferation. Together, these data suggest that SUMO-dependent repression of this group of target genes is responsible for the role of Sox2 in regulating the proliferation of neural stem cells.
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Affiliation(s)
- Elisa Marelli
- School of Life Sciences, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom
| | - Jaime Hughes
- School of Life Sciences, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom
| | - Paul J. Scotting
- School of Life Sciences, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom
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2
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Piacentino ML, Fasse AJ, Camacho-Avila A, Grabylnikov I, Bronner ME. SMPD3 expression is spatially regulated in the developing embryo by SOXE factors. Dev Biol 2024; 506:31-41. [PMID: 38052296 PMCID: PMC10872304 DOI: 10.1016/j.ydbio.2023.11.011] [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: 08/10/2023] [Revised: 11/20/2023] [Accepted: 11/29/2023] [Indexed: 12/07/2023]
Abstract
During epithelial-to-mesenchymal transition (EMT), significant rearrangements occur in plasma membrane protein and lipid content that are important for membrane function and acquisition of cell motility. To gain insight into how neural crest cells regulate their lipid content at the transcriptional level during EMT, here we identify critical enhancer sequences that regulate the expression of SMPD3, a gene responsible for sphingomyelin hydrolysis to produce ceramide and necessary for neural crest EMT. We uncovered three enhancer regions within the first intron of the SMPD3 locus that drive reporter expression in distinct spatial and temporal domains, together collectively recapitulating the expression domains of endogenous SMPD3 within the ectodermal lineages. We further dissected one enhancer that is specifically active in the migrating neural crest. By mutating putative transcriptional input sites or knocking down upstream regulators, we find that the SOXE-family transcription factors SOX9 and SOX10 regulate the expression of SMPD3 in migrating neural crest cells. Further, ChIP-seq and nascent transcription analysis reveal that SOX10 directly regulates expression of an SMPD3 enhancer specific to migratory neural crest cells. Together these results shed light on how core components of developmental gene regulatory networks interact with metabolic effector genes to control changes in membrane lipid content.
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Affiliation(s)
- Michael L Piacentino
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA; Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Aria J Fasse
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Alexis Camacho-Avila
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Ilya Grabylnikov
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
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3
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Thiery AP, Buzzi AL, Hamrud E, Cheshire C, Luscombe NM, Briscoe J, Streit A. scRNA-sequencing in chick suggests a probabilistic model for cell fate allocation at the neural plate border. eLife 2023; 12:e82717. [PMID: 37530410 PMCID: PMC10425176 DOI: 10.7554/elife.82717] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 08/01/2023] [Indexed: 08/03/2023] Open
Abstract
The vertebrate 'neural plate border' is a transient territory located at the edge of the neural plate containing precursors for all ectodermal derivatives: the neural plate, neural crest, placodes and epidermis. Elegant functional experiments in a range of vertebrate models have provided an in-depth understanding of gene regulatory interactions within the ectoderm. However, these experiments conducted at tissue level raise seemingly contradictory models for fate allocation of individual cells. Here, we carry out single cell RNA sequencing of chick ectoderm from primitive streak to neurulation stage, to explore cell state diversity and heterogeneity. We characterise the dynamics of gene modules, allowing us to model the order of molecular events which take place as ectodermal fates segregate. Furthermore, we find that genes previously classified as neural plate border 'specifiers' typically exhibit dynamic expression patterns and are enriched in either neural, neural crest or placodal fates, revealing that the neural plate border should be seen as a heterogeneous ectodermal territory and not a discrete transitional transcriptional state. Analysis of neural, neural crest and placodal markers reveals that individual NPB cells co-express competing transcriptional programmes suggesting that their ultimate identify is not yet fixed. This population of 'border located undecided progenitors' (BLUPs) gradually diminishes as cell fate decisions take place. Considering our findings, we propose a probabilistic model for cell fate choice at the neural plate border. Our data suggest that the probability of a progenitor's daughters to contribute to a given ectodermal derivative is related to the balance of competing transcriptional programmes, which in turn are regulated by the spatiotemporal position of a progenitor.
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Affiliation(s)
- Alexandre P Thiery
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King’s College LondonLondonUnited Kingdom
| | - Ailin Leticia Buzzi
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King’s College LondonLondonUnited Kingdom
| | - Eva Hamrud
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King’s College LondonLondonUnited Kingdom
| | - Chris Cheshire
- Bioinformatics and Computational Biology Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Nicholas M Luscombe
- Bioinformatics and Computational Biology Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - James Briscoe
- Bioinformatics and Computational Biology Laboratory, The Francis Crick InstituteLondonUnited Kingdom
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King’s College LondonLondonUnited Kingdom
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4
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Alata Jimenez N, Strobl-Mazzulla PH. Folate Carrier Deficiency Drives Differential Methylation and Enhanced Cellular Potency in the Neural Plate Border. Front Cell Dev Biol 2022; 10:834625. [PMID: 35912103 PMCID: PMC9326018 DOI: 10.3389/fcell.2022.834625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 06/07/2022] [Indexed: 11/28/2022] Open
Abstract
The neural plate border (NPB) of vertebrate embryos segregates from the neural and epidermal regions, and it is comprised of an intermingled group of multipotent progenitor cells. Folate is the precursor of S-adenosylmethionine, the main methyl donor for DNA methylation, and it is critical for embryonic development, including the specification of progenitors which reside in the NPB. Despite the fact that several intersecting signals involved in the specification and territorial restriction of NPB cells are known, the role of epigenetics, particularly DNA methylation, has been a matter of debate. Here, we examined the temporal and spatial distribution of the methyl source and analyzed the abundance of 5mC/5 hmC and their epigenetic writers throughout the segregation of the neural and NPB territories. Reduced representation bisulfite sequencing (RRBS) on Reduced Folate Carrier 1 (RFC1)-deficient embryos leads to the identification of differentially methylated regions (DMRs). In the RFC1-deficient embryos, we identified several DMRs in the Notch1 locus, and the spatiotemporal expression of Notch1 and its downstream target gene Bmp4 were expanded in the NPB. Cell fate analysis on folate deficient embryos revealed a significant increase in the number of cells coexpressing both neural (SOX2) and NPB (PAX7) markers, which may represent an enhancing effect in the cellular potential of those progenitors. Taken together, our findings propose a model where the RFC1 deficiency drives methylation changes in specific genomic regions that are correlated with a dysregulation of pathways involved in early development such as Notch1 and BMP4 signaling. These changes affect the potency of the progenitors residing in the juncture of the neural plate and NPB territories, thus driving them to a primed state.
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5
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Buzzi AL, Chen J, Thiery A, Delile J, Streit A. Sox8 remodels the cranial ectoderm to generate the ear. Proc Natl Acad Sci U S A 2022; 119:e2118938119. [PMID: 35867760 PMCID: PMC9282420 DOI: 10.1073/pnas.2118938119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
The vertebrate inner ear arises from a pool of progenitors with the potential to contribute to all the sense organs and cranial ganglia in the head. Here, we explore the molecular mechanisms that control ear specification from these precursors. Using a multiomics approach combined with loss-of-function experiments, we identify a core transcriptional circuit that imparts ear identity, along with a genome-wide characterization of noncoding elements that integrate this information. This analysis places the transcription factor Sox8 at the top of the ear determination network. Introducing Sox8 into the cranial ectoderm not only converts non-ear cells into ear progenitors but also activates the cellular programs for ear morphogenesis and neurogenesis. Thus, Sox8 has the unique ability to remodel transcriptional networks in the cranial ectoderm toward ear identity.
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Affiliation(s)
- Ailin Leticia Buzzi
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
| | - Jingchen Chen
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
| | - Alexandre Thiery
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
| | - Julien Delile
- The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, King’s College London, London SE1 9RT, United Kingdom
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6
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Vanni V, Salonna M, Gasparini F, Martini M, Anselmi C, Gissi C, Manni L. Yamanaka Factors in the Budding Tunicate Botryllus schlosseri Show a Shared Spatio-Temporal Expression Pattern in Chordates. Front Cell Dev Biol 2022; 10:782722. [PMID: 35342743 PMCID: PMC8948423 DOI: 10.3389/fcell.2022.782722] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 02/09/2022] [Indexed: 01/22/2023] Open
Abstract
In vertebrates, the four transcription factors Sox2, c-Myc, Pou5f1 and Klf4 are involved in the differentiation of several tissues during vertebrate embryogenesis; moreover, they are normally co-expressed in embryonic stem cells and play roles in pluripotency, self-renewal, and maintenance of the undifferentiated state in adult cells. The in vitro forced co-expression of these factors, named Yamanaka factors (YFs), induces pluripotency in human or mouse fibroblasts. Botryllus schlosseri is a colonial tunicate undergoing continuous stem cell-mediated asexual development, providing a valuable model system for the study of pluripotency in the closest living relatives of vertebrates. In this study, we identified B. schlosseri orthologs of human Sox2 and c-Myc genes, as well as the closest homologs of the vertebrate-specific Pou5f1 gene, through an in-depth evolutionary analysis of the YF gene families in tunicates and other deuterostomes. Then, we studied the expression of these genes during the asexual cycle of B. schlosseri using in situ hybridization in order to investigate their possible involvement in tissue differentiation and in pluripotency maintenance. Our results show a shared spatio-temporal expression pattern consistent with the reported functions of these genes in invertebrate and vertebrate embryogenesis. Moreover, Myc, SoxB1 and Pou3 were expressed in candidate stem cells residing in their niches, while Pou2 was found expressed exclusively in the immature previtellogenic oocytes, both in gonads and circulating in the colonial vascular system. Our data suggest that Myc, SoxB1 and Pou3 may be individually involved in the differentiation of the same territories seen in other chordates, and that, together, they may play a role in stemness even in this colonial ascidian.
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Affiliation(s)
- Virginia Vanni
- Department of Biology, University of Padova, Padova, Italy
| | - Marika Salonna
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | | | | | - Chiara Anselmi
- Stanford University, Hopkins Marine Station, Pacific Grove, CA, United States.,Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA, United States
| | - Carmela Gissi
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy.,IBIOM, Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Consiglio Nazionale Delle Ricerche, Bari, Italy.,CoNISMa, Consorzio Nazionale Interuniversitario per le Scienze Del Mare, Roma, Italy
| | - Lucia Manni
- Department of Biology, University of Padova, Padova, Italy
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7
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Riley BB. Comparative assessment of Fgf's diverse roles in inner ear development: A zebrafish perspective. Dev Dyn 2021; 250:1524-1551. [PMID: 33830554 DOI: 10.1002/dvdy.343] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/26/2021] [Accepted: 03/26/2021] [Indexed: 01/21/2023] Open
Abstract
Progress in understanding mechanisms of inner ear development has been remarkably rapid in recent years. The research community has benefited from the availability of several diverse model organisms, including zebrafish, chick, and mouse. The complexity of the inner ear has proven to be a challenge, and the complexity of the mammalian cochlea in particular has been the subject of intense scrutiny. Zebrafish lack a cochlea and exhibit a number of other differences from amniote species, hence they are sometimes seen as less relevant for inner ear studies. However, accumulating evidence shows that underlying cellular and molecular mechanisms are often highly conserved. As a case in point, consideration of the diverse functions of Fgf and its downstream effectors reveals many similarities between vertebrate species, allowing meaningful comparisons the can benefit the entire research community. In this review, I will discuss mechanisms by which Fgf controls key events in early otic development in zebrafish and provide direct comparisons with chick and mouse.
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Affiliation(s)
- Bruce B Riley
- Biology Department, Texas A&M University, College Station, Texas, USA
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8
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Abstract
Neural crest stem/progenitor cells arise early during vertebrate embryogenesis at the border of the forming central nervous system. They subsequently migrate throughout the body, eventually differentiating into diverse cell types ranging from neurons and glia of the peripheral nervous system to bones of the face, portions of the heart, and pigmentation of the skin. Along the body axis, the neural crest is heterogeneous, with different subpopulations arising in the head, neck, trunk, and tail regions, each characterized by distinct migratory patterns and developmental potential. Modern genomic approaches like single-cell RNA- and ATAC-sequencing (seq) have greatly enhanced our understanding of cell lineage trajectories and gene regulatory circuitry underlying the developmental progression of neural crest cells. Here, we discuss how genomic approaches have provided new insights into old questions in neural crest biology by elucidating transcriptional and posttranscriptional mechanisms that govern neural crest formation and the establishment of axial level identity. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Shashank Gandhi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA; ,
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, USA; ,
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9
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Schock EN, LaBonne C. Sorting Sox: Diverse Roles for Sox Transcription Factors During Neural Crest and Craniofacial Development. Front Physiol 2020; 11:606889. [PMID: 33424631 PMCID: PMC7793875 DOI: 10.3389/fphys.2020.606889] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 11/09/2020] [Indexed: 12/31/2022] Open
Abstract
Sox transcription factors play many diverse roles during development, including regulating stem cell states, directing differentiation, and influencing the local chromatin landscape. Of the twenty vertebrate Sox factors, several play critical roles in the development the neural crest, a key vertebrate innovation, and the subsequent formation of neural crest-derived structures, including the craniofacial complex. Herein, we review the specific roles for individual Sox factors during neural crest cell formation and discuss how some factors may have been essential for the evolution of the neural crest. Additionally, we describe how Sox factors direct neural crest cell differentiation into diverse lineages such as melanocytes, glia, and cartilage and detail their involvement in the development of specific craniofacial structures. Finally, we highlight several SOXopathies associated with craniofacial phenotypes.
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Affiliation(s)
- Elizabeth N Schock
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States
| | - Carole LaBonne
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States.,NSF-Simons Center for Quantitative Biology, Northwestern University, Evanston, IL, United States
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10
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Thawani A, Groves AK. Building the Border: Development of the Chordate Neural Plate Border Region and Its Derivatives. Front Physiol 2020; 11:608880. [PMID: 33364980 PMCID: PMC7750469 DOI: 10.3389/fphys.2020.608880] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/19/2020] [Indexed: 01/04/2023] Open
Abstract
The paired cranial sensory organs and peripheral nervous system of vertebrates arise from a thin strip of cells immediately adjacent to the developing neural plate. The neural plate border region comprises progenitors for four key populations of cells: neural plate cells, neural crest cells, the cranial placodes, and epidermis. Putative homologues of these neural plate border derivatives can be found in protochordates such as amphioxus and tunicates. In this review, we summarize key signaling pathways and transcription factors that regulate the inductive and patterning events at the neural plate border region that give rise to the neural crest and placodal lineages. Gene regulatory networks driven by signals from WNT, fibroblast growth factor (FGF), and bone morphogenetic protein (BMP) signaling primarily dictate the formation of the crest and placodal lineages. We review these studies and discuss the potential of recent advances in spatio-temporal transcriptomic and epigenomic analyses that would allow a mechanistic understanding of how these signaling pathways and their downstream transcriptional cascades regulate the formation of the neural plate border region.
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Affiliation(s)
- Ankita Thawani
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
| | - Andrew K Groves
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
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11
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Serrano Nájera G, Weijer CJ. Cellular processes driving gastrulation in the avian embryo. Mech Dev 2020; 163:103624. [PMID: 32562871 PMCID: PMC7511600 DOI: 10.1016/j.mod.2020.103624] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/18/2020] [Accepted: 05/28/2020] [Indexed: 01/18/2023]
Abstract
Gastrulation consists in the dramatic reorganisation of the epiblast, a one-cell thick epithelial sheet, into a multilayered embryo. In chick, the formation of the internal layers requires the generation of a macroscopic convection-like flow, which involves up to 50,000 epithelial cells in the epiblast. These cell movements locate the mesendoderm precursors into the midline of the epiblast to form the primitive streak. There they acquire a mesenchymal phenotype, ingress into the embryo and migrate outward to populate the inner embryonic layers. This review covers what is currently understood about how cell behaviours ultimately cause these morphogenetic events and how they are regulated. We discuss 1) how the biochemical patterning of the embryo before gastrulation creates compartments of differential cell behaviours, 2) how the global epithelial flows arise from the coordinated actions of individual cells, 3) how the cells delaminate individually from the epiblast during the ingression, and 4) how cells move after the ingression following stereotypical migration routes. We conclude by exploring new technical advances that will facilitate future research in the chick model system.
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Affiliation(s)
- Guillermo Serrano Nájera
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Cornelis J Weijer
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
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12
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Cell fate decisions during the development of the peripheral nervous system in the vertebrate head. Curr Top Dev Biol 2020; 139:127-167. [PMID: 32450959 DOI: 10.1016/bs.ctdb.2020.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Sensory placodes and neural crest cells are among the key cell populations that facilitated the emergence and diversification of vertebrates throughout evolution. Together, they generate the sensory nervous system in the head: both form the cranial sensory ganglia, while placodal cells make major contributions to the sense organs-the eye, ear and olfactory epithelium. Both are instrumental for integrating craniofacial organs and have been key to drive the concentration of sensory structures in the vertebrate head allowing the emergence of active and predatory life forms. Whereas the gene regulatory networks that control neural crest cell development have been studied extensively, the signals and downstream transcriptional events that regulate placode formation and diversity are only beginning to be uncovered. Both cell populations are derived from the embryonic ectoderm, which also generates the central nervous system and the epidermis, and recent evidence suggests that their initial specification involves a common molecular mechanism before definitive neural, neural crest and placodal lineages are established. In this review, we will first discuss the transcriptional networks that pattern the embryonic ectoderm and establish these three cell fates with emphasis on sensory placodes. Second, we will focus on how sensory placode precursors diversify using the specification of otic-epibranchial progenitors and their segregation as an example.
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13
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Characterization of gonad differentially expressed SoxB2 genes in mud crab Scylla paramamosain. Gene 2020; 740:144507. [DOI: 10.1016/j.gene.2020.144507] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 01/26/2020] [Accepted: 02/21/2020] [Indexed: 12/25/2022]
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14
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Liu K, Ma W, Li C, Li J, Zhang X, Liu J, Liu W, Wu Z, Zang C, Liang Y, Guo J, Li L. Advances in Transcription Factors Related to Neuroglial Cell Reprogramming. Transl Neurosci 2020; 11:17-27. [PMID: 32161682 PMCID: PMC7053399 DOI: 10.1515/tnsci-2020-0004] [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: 08/23/2019] [Accepted: 01/07/2020] [Indexed: 11/27/2022] Open
Abstract
Neuroglial cells have a high level of plasticity, and many types of these cells are present in the nervous system. Neuroglial cells provide diverse therapeutic targets for neurological diseases and injury repair. Cell reprogramming technology provides an efficient pathway for cell transformation during neural regeneration, while transcription factor-mediated reprogramming can facilitate the understanding of how neuroglial cells mature into functional neurons and promote neurological function recovery.
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Affiliation(s)
- Kuangpin Liu
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Wei Ma
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Chunyan Li
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Junjun Li
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Xingkui Zhang
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Jie Liu
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Wei Liu
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Zheng Wu
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, Yunnan, China
| | - Chenghao Zang
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, Yunnan, China
| | - Yu Liang
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
| | - Jianhui Guo
- Second Department of General Surgery, First People's Hospital of Yunnan Province, Kunming, Yunnan, China
| | - Liyan Li
- Institute of Neuroscience, Kunming Medical University, Kunming, Yunnan, China
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15
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Iida H, Furukawa Y, Teramoto M, Suzuki H, Takemoto T, Uchikawa M, Kondoh H. Sox2 gene regulation via the D1 enhancer in embryonic neural tube and neural crest by the combined action of SOX2 and ZIC2. Genes Cells 2020; 25:242-256. [PMID: 31997540 DOI: 10.1111/gtc.12753] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/26/2020] [Accepted: 01/27/2020] [Indexed: 01/12/2023]
Abstract
The transcription factor (TF) SOX2 regulates various stem cells and tissue progenitors via functional interactions with cell type-specific partner TFs that co-bind to enhancer sequences. Neural progenitors are the major embryonic tissues where SOX2 assumes central regulatory roles. In order to characterize the partner TFs of SOX2 in neural progenitors, we investigated the regulation of the D1 enhancer of the Sox2 gene, which is activated in the embryonic neural tube (NT) and neural crest (NC), using chicken embryo electroporation. We identified essential TF binding sites for a SOX, and two ZIC TFs in the activation of the D1 enhancer. By comparison of dorso-ventral and antero-posterior patterns of D1 enhancer activation, and the effect of mutations on the enhancer activation patterns with TF expression patterns, we determined SOX2 and ZIC2 as the major D1 enhancer-activating TFs. Binding of these TFs to the D1 enhancer sequence was confirmed by chromatin immunoprecipitation analysis. The combination of SOX2 and ZIC2 TFs activated the enhancer in both the NT and NC. These results indicate that SOX2 and ZIC2, which have been known to play major regulatory roles in neural progenitors, do functionally cooperate. In addition, the recently demonstrated SOX2 expression during the NC development is accounted for at least partly by the D1 enhancer activity. Deletion of the D1 enhancer sequence from the mouse genome, however, did not affect the mouse development, indicating functional redundancies of other enhancers.
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Affiliation(s)
- Hideaki Iida
- Faculty of Life Sciences and Institutes for Protein Dynamics and Comprehensive Research, Kyoto Sangyo University, Kyoto, Japan
| | - Yoko Furukawa
- Faculty of Life Sciences and Institutes for Protein Dynamics and Comprehensive Research, Kyoto Sangyo University, Kyoto, Japan
| | - Machiko Teramoto
- Faculty of Life Sciences and Institutes for Protein Dynamics and Comprehensive Research, Kyoto Sangyo University, Kyoto, Japan
| | - Hitomi Suzuki
- Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Tatsuya Takemoto
- Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Masanori Uchikawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Hisato Kondoh
- Faculty of Life Sciences and Institutes for Protein Dynamics and Comprehensive Research, Kyoto Sangyo University, Kyoto, Japan
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16
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Inomata C, Yuikawa T, Nakayama-Sadakiyo Y, Kobayashi K, Ikeda M, Chiba M, Konishi C, Ishioka A, Tsuda S, Yamasu K. Involvement of an Oct4-related PouV gene, pou5f3/pou2, in neurogenesis in the early neural plate of zebrafish embryos. Dev Biol 2020; 457:30-42. [DOI: 10.1016/j.ydbio.2019.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 09/09/2019] [Accepted: 09/10/2019] [Indexed: 01/03/2023]
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17
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Prajapati RS, Hintze M, Streit A. PRDM1 controls the sequential activation of neural, neural crest and sensory progenitor determinants. Development 2019; 146:dev.181107. [PMID: 31806661 DOI: 10.1242/dev.181107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 11/27/2019] [Indexed: 12/25/2022]
Abstract
During early embryogenesis, the ectoderm is rapidly subdivided into neural, neural crest and sensory progenitors. How the onset of lineage determinants and the loss of pluripotency markers are temporally and spatially coordinated in vivo is still debated. Here, we identify a crucial role for the transcription factor PRDM1 in the orderly transition from epiblast to defined neural lineages in chick. PRDM1 is initially expressed broadly in the entire epiblast, but becomes gradually restricted as cell fates are specified. We find that PRDM1 is required for the loss of some pluripotency markers and the onset of neural, neural crest and sensory progenitor specifier genes. PRDM1 directly activates their expression by binding to their promoter regions and recruiting the histone demethylase Kdm4a to remove repressive histone marks. However, once neural lineage determinants become expressed, they in turn repress PRDM1, whereas prolonged PRDM1 expression inhibits neural, neural crest and sensory progenitor genes, suggesting that its downregulation is necessary for cells to maintain their identity. Therefore, PRDM1 plays multiple roles during ectodermal cell fate allocation.
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Affiliation(s)
- Ravindra S Prajapati
- Centre for Craniofacial & Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
| | - Mark Hintze
- Centre for Craniofacial & Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
| | - Andrea Streit
- Centre for Craniofacial & Regenerative Biology, Faculty of Dental, Oral and Craniofacial Sciences, King's College London, London SE1 9RT, UK
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18
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Buitrago-Delgado E, Schock EN, Nordin K, LaBonne C. A transition from SoxB1 to SoxE transcription factors is essential for progression from pluripotent blastula cells to neural crest cells. Dev Biol 2018; 444:50-61. [PMID: 30144418 DOI: 10.1016/j.ydbio.2018.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/10/2018] [Accepted: 08/21/2018] [Indexed: 01/30/2023]
Abstract
The neural crest is a stem cell population unique to vertebrate embryos that gives rise to derivatives from multiple embryonic germ layers. The molecular underpinnings of potency that govern neural crest potential are highly conserved with that of pluripotent blastula stem cells, suggesting that neural crest cells may have evolved through retention of aspects of the pluripotency gene regulatory network (GRN). A striking difference in the regulatory factors utilized in pluripotent blastula cells and neural crest cells is the deployment of different sub-families of Sox transcription factors; SoxB1 factors play central roles in the pluripotency of naïve blastula and ES cells, whereas neural crest cells require SoxE function. Here we explore the shared and distinct activities of these factors to shed light on the role that this molecular hand-off of Sox factor activity plays in the genesis of neural crest and the lineages derived from it. Our findings provide evidence that SoxB1 and SoxE factors have both overlapping and distinct activities in regulating pluripotency and lineage restriction in the embryo. We hypothesize that SoxE factors may transiently replace SoxB1 factors to control pluripotency in neural crest cells, and then poise these cells to contribute to glial, chondrogenic and melanocyte lineages at stages when SoxB1 factors promote neuronal progenitor formation.
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Affiliation(s)
- Elsy Buitrago-Delgado
- Dept. of Molecular Biosciences, Northwestern University, Evanston, IL 60208, United States
| | - Elizabeth N Schock
- Dept. of Molecular Biosciences, Northwestern University, Evanston, IL 60208, United States
| | - Kara Nordin
- Dept. of Molecular Biosciences, Northwestern University, Evanston, IL 60208, United States
| | - Carole LaBonne
- Dept. of Molecular Biosciences, Northwestern University, Evanston, IL 60208, United States; Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL 60208, United States.
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19
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Rogers CD, Sorrells LK, Bronner ME. A catenin-dependent balance between N-cadherin and E-cadherin controls neuroectodermal cell fate choices. Mech Dev 2018; 152:44-56. [PMID: 30009960 PMCID: PMC6112866 DOI: 10.1016/j.mod.2018.07.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/16/2018] [Accepted: 07/02/2018] [Indexed: 01/19/2023]
Abstract
Characterizing endogenous protein expression, interaction and function, this study identifies in vivo interactions and competitive balance between N-cadherin and E-cadherin in developing avian (Gallus gallus) neural and neural crest cells. Numerous cadherin proteins, including neural cadherin (Ncad) and epithelial cadherin (Ecad), are expressed in the developing neural plate as well as in neural crest cells as they delaminate from the newly closed neural tube. To clarify independent or coordinate function during development, we examined their expression in the cranial region. The results revealed surprising overlap and distinct localization of Ecad and Ncad in the neural tube. Using a proximity ligation assay and co-immunoprecipitation, we found that Ncad and Ecad formed heterotypic complexes in the developing neural tube, and that modulation of Ncad levels led to reciprocal gain or reduction of Ecad protein, which then alters ectodermal cell fate. Here, we demonstrate that the balance of Ecad and Ncad is dependent upon the availability of β-catenin proteins, and that alteration of either classical cadherin modifies the proportions of the neural crest and neuroectodermal cells that are specified.
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Affiliation(s)
- Crystal D Rogers
- Department of Biology, California State University, Northridge, Northridge, CA 91330, United States of America.
| | - Lisa K Sorrells
- Department of Biology, California State University, Northridge, Northridge, CA 91330, United States of America.
| | - Marianne E Bronner
- Division of Biology and Biological Engineering 139-74, California Institute of Technology, Pasadena, CA 91125, United States of America.
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20
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Betters E, Charney RM, Garcia-Castro MI. Early specification and development of rabbit neural crest cells. Dev Biol 2018; 444 Suppl 1:S181-S192. [PMID: 29932896 DOI: 10.1016/j.ydbio.2018.06.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/01/2018] [Accepted: 06/18/2018] [Indexed: 11/19/2022]
Abstract
The phenomenal migratory and differentiation capacity of neural crest cells has been well established across model organisms. While the earliest stages of neural crest development have been investigated in non-mammalian model systems such as Xenopus and Aves, the early specification of this cell population has not been evaluated in mammalian embryos, of which the murine model is the most prevalent. Towards a more comprehensive understanding of mammalian neural crest formation and human comparative studies, we have used the rabbit as a mammalian system for the study of early neural crest specification and development. We examine the expression profile of well-characterized neural crest markers in rabbit embryos across developmental time from early gastrula to later neurula stages, and provide a comparison to markers of migratory neural crest in the chick. Importantly, we apply explant specification assays to address the pivotal question of mammalian neural crest ontogeny, and provide the first evidence that a specified population of neural crest cells exists in the rabbit gastrula prior to the overt expression of neural crest markers. Finally, we demonstrate that FGF signaling is necessary for early rabbit neural crest formation, as SU5402 treatment strongly represses neural crest marker expression in explant assays. This study pioneers the rabbit as a model for neural crest development, and provides the first demonstration of mammalian neural crest specification and the requirement of FGF signaling in this process.
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Affiliation(s)
- Erin Betters
- School of Medicine Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
| | - Rebekah M Charney
- School of Medicine Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA
| | - Martín I Garcia-Castro
- School of Medicine Division of Biomedical Sciences, University of California, Riverside, CA 92521, USA.
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21
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Vermillion KL, Bacher R, Tannenbaum AP, Swanson S, Jiang P, Chu LF, Stewart R, Thomson JA, Vereide DT. Spatial patterns of gene expression are unveiled in the chick primitive streak by ordering single-cell transcriptomes. Dev Biol 2018; 439:30-41. [PMID: 29678445 DOI: 10.1016/j.ydbio.2018.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 01/07/2023]
Abstract
During vertebrate development, progenitor cells give rise to tissues and organs through a complex choreography that commences at gastrulation. A hallmark event of gastrulation is the formation of the primitive streak, a linear assembly of cells along the anterior-posterior (AP) axis of the developing organism. To examine the primitive streak at a single-cell resolution, we measured the transcriptomes of individual chick cells from the streak or the surrounding tissue (the rest of the area pellucida) in Hamburger-Hamilton stage 4 embryos. The single-cell transcriptomes were then ordered by the statistical method Wave-Crest to deduce both the relative position along the AP axis and the prospective lineage of single cells. The ordered transcriptomes reveal intricate patterns of gene expression along the primitive streak.
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Affiliation(s)
| | - Rhonda Bacher
- Department of Biostatistics, University of Florida, Gainesville, FL 32611, USA
| | | | - Scott Swanson
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Peng Jiang
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Li-Fang Chu
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - Ron Stewart
- Morgridge Institute for Research, Madison, WI 53715, USA
| | - James A Thomson
- Morgridge Institute for Research, Madison, WI 53715, USA; Department of Cell&Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA; Department of Molecular, Cellular,&Developmental Biology, University of California, Santa Barbara, CA 93106, USA
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22
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Han JY, Lee HG, Park YH, Hwang YS, Kim SK, Rengaraj D, Cho BW, Lim JM. Acquisition of pluripotency in the chick embryo occurs during intrauterine embryonic development via a unique transcriptional network. J Anim Sci Biotechnol 2018; 9:31. [PMID: 29644074 PMCID: PMC5891889 DOI: 10.1186/s40104-018-0246-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/26/2018] [Indexed: 12/18/2022] Open
Abstract
Background Acquisition of pluripotency by transcriptional regulatory factors is an initial developmental event that is required for regulation of cell fate and lineage specification during early embryonic development. The evolutionarily conserved core transcriptional factors regulating the pluripotency network in fishes, amphibians, and mammals have been elucidated. There are also species-specific maternally inherited transcriptional factors and their intricate transcriptional networks important in the acquisition of pluripotency. In avian species, however, the core transcriptional network that governs the acquisition of pluripotency during early embryonic development is not well understood. Results We found that chicken NANOG (cNANOG) was expressed in the stages between the pre-ovulatory follicle and oocyte and was continuously detected in Eyal-Giladi and Kochav stage I (EGK.I) to X. However, cPOUV was not expressed during folliculogenesis, but began to be detectable between EGK.V and VI. Unexpectedly, cSOX2 could not be detected during folliculogenesis and intrauterine embryonic development. Instead of cSOX2, cSOX3 was maternally inherited and continuously expressed during chicken intrauterine development. In addition, we found that the pluripotency-related genes such as cENS-1, cKIT, cLIN28A, cMYC, cPRDM14, and cSALL4 began to be dramatically upregulated between EGK.VI and VIII. Conclusion These results suggest that chickens have a unique pluripotent circuitry since maternally inherited cNANOG and cSOX3 may play an important role in the initial acquisition of pluripotency. Moreover, the acquisition of pluripotency in chicken embryos occurs at around EGK.VI to VIII.
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Affiliation(s)
- Jae Yong Han
- 1Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Korea.,2Institute for Biomedical Sciences, Shinshu University, Minamiminowa, Nagano, 399-4598 Japan
| | - Hyo Gun Lee
- 1Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Korea
| | - Young Hyun Park
- 1Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Korea
| | - Young Sun Hwang
- 1Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Korea
| | - Sang Kyung Kim
- 1Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Korea
| | - Deivendran Rengaraj
- 3Department of Animal Science and Technology, Chung-Ang University, Anseong, Gyeonggi-do 17546 Korea
| | - Byung Wook Cho
- 4Department of Animal Science, College of Natural Resources and Life Sciences, Pusan National University, Miryang, 50463 Korea
| | - Jeong Mook Lim
- 1Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826 Korea
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23
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Xia X, Huo W, Wan R, Wang P, Zhang L, Chang Z. Molecular cloning, characterization, and expression profiles of the
Sox3
gene in Chinese loach
Paramisgurnus dabryanus. Evol Dev 2018; 20:108-118. [DOI: 10.1111/ede.12252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaohua Xia
- College of Life ScienceHenan Normal UniversityXinxiangHenanPeople's Republic of China
| | - Weiran Huo
- College of Life ScienceHenan Normal UniversityXinxiangHenanPeople's Republic of China
| | - Ruyan Wan
- College of Life ScienceHenan Normal UniversityXinxiangHenanPeople's Republic of China
| | - Peijin Wang
- College of Life ScienceHenan Normal UniversityXinxiangHenanPeople's Republic of China
| | - Linxia Zhang
- College of Life ScienceHenan Normal UniversityXinxiangHenanPeople's Republic of China
| | - Zhongjie Chang
- College of Life ScienceHenan Normal UniversityXinxiangHenanPeople's Republic of China
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24
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Nasal and otic placode specific regulation of Sox2 involves both activation by Sox-Sall4 synergism and multiple repression mechanisms. Dev Biol 2018; 433:61-74. [DOI: 10.1016/j.ydbio.2017.11.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/02/2017] [Accepted: 11/10/2017] [Indexed: 01/21/2023]
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25
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Hintze M, Prajapati RS, Tambalo M, Christophorou NAD, Anwar M, Grocott T, Streit A. Cell interactions, signals and transcriptional hierarchy governing placode progenitor induction. Development 2017; 144:2810-2823. [PMID: 28684624 PMCID: PMC5560042 DOI: 10.1242/dev.147942] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 06/21/2017] [Indexed: 12/18/2022]
Abstract
In vertebrates, cranial placodes contribute to all sense organs and sensory ganglia and arise from a common pool of Six1/Eya2+ progenitors. Here we dissect the events that specify ectodermal cells as placode progenitors using newly identified genes upstream of the Six/Eya complex. We show in chick that two different tissues, namely the lateral head mesoderm and the prechordal mesendoderm, gradually induce placode progenitors: cells pass through successive transcriptional states, each identified by distinct factors and controlled by different signals. Both tissues initiate a common transcriptional state but over time impart regional character, with the acquisition of anterior identity dependent on Shh signalling. Using a network inference approach we predict the regulatory relationships among newly identified transcription factors and verify predicted links in knockdown experiments. Based on this analysis we propose a new model for placode progenitor induction, in which the initial induction of a generic transcriptional state precedes regional divergence.
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Affiliation(s)
- Mark Hintze
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Ravindra Singh Prajapati
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Monica Tambalo
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Nicolas A D Christophorou
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Maryam Anwar
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Timothy Grocott
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
| | - Andrea Streit
- Department of Craniofacial Development & Stem Cell Biology, King's College London, Dental Institute, London SE1 9RT, UK
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26
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Cyclin-Dependent Kinase-Dependent Phosphorylation of Sox2 at Serine 39 Regulates Neurogenesis. Mol Cell Biol 2017; 37:MCB.00201-17. [PMID: 28584195 DOI: 10.1128/mcb.00201-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/25/2017] [Indexed: 01/05/2023] Open
Abstract
Sox2 is known to be important for neuron formation, but the precise mechanism through which it activates a neurogenic program and how this differs from its well-established function in self-renewal of stem cells remain elusive. In this study, we identified a highly conserved cyclin-dependent kinase (Cdk) phosphorylation site on serine 39 (S39) in Sox2. In neural stem cells (NSCs), phosphorylation of S39 enhances the ability of Sox2 to negatively regulate neuronal differentiation, while loss of phosphorylation is necessary for chromatin retention of a truncated form of Sox2 generated during neurogenesis. We further demonstrated that nonphosphorylated cleaved Sox2 specifically induces the expression of proneural genes and promotes neurogenic commitment in vivo Our present study sheds light on how the level of Cdk kinase activity directly regulates Sox2 to tip the balance between self-renewal and differentiation in NSCs.
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27
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Human Mesenchymal Stem Cells from Adipose Tissue Differentiated into Neuronal or Glial Phenotype Express Different Aquaporins. Mol Neurobiol 2016; 54:8308-8320. [PMID: 27921242 DOI: 10.1007/s12035-016-0312-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/21/2016] [Indexed: 12/31/2022]
Abstract
Aquaporins (AQPs) are 13 integral membrane proteins that provide selective pores for the rapid movement of water and other uncharged solutes, across cell membranes. Recently, AQPs have been focused for their role in production, circulation, and homeostasis of the cerebrospinal fluid and their importance in several human diseases is becoming clear. This study investigated the time course (0, 14, and 28 days) of AQP1, 4, 7, 8, and 9 during the neural differentiation of human mesenchymal stem cells (MSCs) from adipose tissue (AT). For this purpose, two different media, enriched with serum or B-27 and N1 supplements, were applied to give a stimulus toward neural lineage. After 14 days, the cells were cultured with neuronal or glial differentiating medium for further 14 days. The results confirmed that AT-MSCs could be differentiated into neurons, astrocytes, and oligodendrocytes, expressing not only the typical neural markers but also specific AQPs depending on differentiated cell type. Our data demonstrated that at 28 days, AT-MSCs express only AQP1; astrocytes AQP1, 4, and 7; oligodendrocytes AQP1, 4, and 8; and finally neurons AQP1 and 7. This study provides fundamental insight into the biology of the mesenchymal stem cells and it suggests that AQPs can be potential neural markers.
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28
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Peretz Y, Eren N, Kohl A, Hen G, Yaniv K, Weisinger K, Cinnamon Y, Sela-Donenfeld D. A new role of hindbrain boundaries as pools of neural stem/progenitor cells regulated by Sox2. BMC Biol 2016; 14:57. [PMID: 27392568 PMCID: PMC4938926 DOI: 10.1186/s12915-016-0277-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/21/2016] [Indexed: 01/28/2023] Open
Abstract
Background Compartment boundaries are an essential developmental mechanism throughout evolution, designated to act as organizing centers and to regulate and localize differently fated cells. The hindbrain serves as a fascinating example for this phenomenon as its early development is devoted to the formation of repetitive rhombomeres and their well-defined boundaries in all vertebrates. Yet, the actual role of hindbrain boundaries remains unresolved, especially in amniotes. Results Here, we report that hindbrain boundaries in the chick embryo consist of a subset of cells expressing the key neural stem cell (NSC) gene Sox2. These cells co-express other neural progenitor markers such as Transitin (the avian Nestin), GFAP, Pax6 and chondroitin sulfate proteoglycan. The majority of the Sox2+ cells that reside within the boundary core are slow-dividing, whereas nearer to and within rhombomeres Sox2+ cells are largely proliferating. In vivo analyses and cell tracing experiments revealed the contribution of boundary Sox2+ cells to neurons in a ventricular-to-mantle manner within the boundaries, as well as their lateral contribution to proliferating Sox2+ cells in rhombomeres. The generation of boundary-derived neurospheres from hindbrain cultures confirmed the typical NSC behavior of boundary cells as a multipotent and self-renewing Sox2+ cell population. Inhibition of Sox2 in boundaries led to enhanced and aberrant neural differentiation together with inhibition in cell-proliferation, whereas Sox2 mis-expression attenuated neurogenesis, confirming its significant function in hindbrain neuronal organization. Conclusions Data obtained in this study deciphers a novel role of hindbrain boundaries as repetitive pools of neural stem/progenitor cells, which provide proliferating progenitors and differentiating neurons in a Sox2-dependent regulation. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0277-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yuval Peretz
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Noa Eren
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Ayelet Kohl
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Gideon Hen
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Karina Yaniv
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Karen Weisinger
- Department of Stem Cell and Regenerative Biology, Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA
| | - Yuval Cinnamon
- Institute of Animal Sciences, Department of Poultry and Aquaculture Sciences, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel.
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29
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Mak SS, Alev C, Nagai H, Wrabel A, Matsuoka Y, Honda A, Sheng G, Ladher RK. Characterization of the finch embryo supports evolutionary conservation of the naive stage of development in amniotes. eLife 2015; 4:e07178. [PMID: 26359635 PMCID: PMC4608004 DOI: 10.7554/elife.07178] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 09/10/2015] [Indexed: 02/06/2023] Open
Abstract
Innate pluripotency of mouse embryos transits from naive to primed state as the inner cell mass differentiates into epiblast. In vitro, their counterparts are embryonic (ESCs) and epiblast stem cells (EpiSCs), respectively. Activation of the FGF signaling cascade results in mouse ESCs differentiating into mEpiSCs, indicative of its requirement in the shift between these states. However, only mouse ESCs correspond to the naive state; ESCs from other mammals and from chick show primed state characteristics. Thus, the significance of the naive state is unclear. In this study, we use zebra finch as a model for comparative ESC studies. The finch blastoderm has mESC-like properties, while chick blastoderm exhibits EpiSC features. In the absence of FGF signaling, finch cells retained expression of pluripotent markers, which were lost in cells from chick or aged finch epiblasts. Our data suggest that the naive state of pluripotency is evolutionarily conserved among amniotes.
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Affiliation(s)
- Siu-Shan Mak
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Cantas Alev
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Hiroki Nagai
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Anna Wrabel
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, Kobe, Japan
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Yoko Matsuoka
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Akira Honda
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Guojun Sheng
- Laboratory for Early Embryogenesis, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Raj K Ladher
- Laboratory for Sensory Development, RIKEN Center for Developmental Biology, Kobe, Japan
- National Center for Biological Sciences, Bengaluru, India
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30
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Canning DR, Brelsford NR, Lovett NW. Chondroitin sulfate effects on neural stem cell differentiation. In Vitro Cell Dev Biol Anim 2015; 52:35-44. [PMID: 26288008 DOI: 10.1007/s11626-015-9941-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/10/2015] [Indexed: 11/25/2022]
Abstract
We have investigated the role chondroitin sulfate has on cell interactions during neural plate formation in the early chick embryo. Using tissue culture isolates from the prospective neural plate, we have measured neural gene expression profiles associated with neural stem cell differentiation. Removal of chondroitin sulfate from stage 4 neural plate tissue leads to altered associations of N-cadherin-positive neural progenitors and causes changes in the normal sequence of neural marker gene expression. Absence of chondroitin sulfate in the neural plate leads to reduced Sox2 expression and is accompanied by an increase in the expression of anterior markers of neural regionalization. Results obtained in this study suggest that the presence of chondroitin sulfate in the anterior chick embryo is instrumental in maintaining cells in the neural precursor state.
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Affiliation(s)
- David R Canning
- Department of Biological Sciences, Murray State University, Murray, KY, 42071, USA.
| | - Natalie R Brelsford
- Department of Biological Sciences, Murray State University, Murray, KY, 42071, USA
| | - Neil W Lovett
- Department of Biological Sciences, Murray State University, Murray, KY, 42071, USA
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Cheah PS, Thomas PQ. SOX3 expression in the glial system of the developing and adult mouse cerebellum. SPRINGERPLUS 2015; 4:400. [PMID: 26261758 PMCID: PMC4527974 DOI: 10.1186/s40064-015-1194-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/29/2015] [Indexed: 11/17/2022]
Abstract
Background The cerebellum plays a vital role in equilibrium, motor control, and motor learning. The discrete neural and glial fates of cerebellar cells are determined by the molecular specifications (e.g. transcription factors) of neuroprogenitor cells that are influenced by local microenvironment signals. In this study, we evaluated the expression and function of Sox3, a single-exon gene located on the X chromosome, in the developing cerebellum. Result In the embryonic and early postnatal cerebellum, SOX3-positive-cells were detected in the ventricular zone, indicating that SOX3 expression is present in a subset of the cerebellar precursor cell population. In the young adult cerebellum, this expression was diminished in cerebellar cells, suggesting its limited role in cerebellar progenitors. SOX3-positive-cells were also found in the cerebellar mantle zone. Further immunohistochemistry analyses revealed that SOX3 was not expressed in Purkinje neurons. Using glial markers in the early postnatal cerebellum, we found that virtually all of the SOX3-positive-cells were glial cells, although not all glial cells were SOX3-positive-cells. We also determined the impact of transgenic expression using a loss-of-function (Sox3 null) model. We did not observe any developmental defects in the cerebellum of the Sox3 null mice. Conclusions Our results indicate that the SOX3 protein is not expressed in cerebellar neurons and is instead expressed exclusively in the cerebellar glial system in a subset of mature glial cells. Although the expression of Sox3 cerebellar glial development is lineage-restricted, it appears that the absence of Sox3 in the ventricular germinal epithelium and migrating glia does not affect cerebellar development, suggesting functional redundancy with other SoxB1 subgroup genes. Electronic supplementary material The online version of this article (doi:10.1186/s40064-015-1194-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pike-See Cheah
- Department of Human Anatomy, Faculty of Medicine, Health Sciences, University Putra Malaysia, 43400 Serdang, Selangor Malaysia ; Neurobiology and Genetics Group, Genetics and Regenerative Medicine Research Center, Faculty of Medicine and Health Sciences, University Putra Malaysia, 43400 Serdang, Malaysia
| | - Paul Q Thomas
- Discipline of Biochemistry, School of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, Australia
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Expression of a novel serine/threonine kinase gene, Ulk4, in neural progenitors during Xenopus laevis forebrain development. Neuroscience 2015; 290:61-79. [DOI: 10.1016/j.neuroscience.2014.12.060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/30/2014] [Accepted: 12/31/2014] [Indexed: 01/11/2023]
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Edlund RK, Birol O, Groves AK. The role of foxi family transcription factors in the development of the ear and jaw. Curr Top Dev Biol 2015; 111:461-95. [PMID: 25662269 DOI: 10.1016/bs.ctdb.2014.11.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mammalian outer, middle, and inner ears have different embryonic origins and evolved at different times in the vertebrate lineage. The outer ear is derived from first and second branchial arch ectoderm and mesoderm, the middle ear ossicles are derived from neural crest mesenchymal cells that invade the first and second branchial arches, whereas the inner ear and its associated vestibule-acoustic (VIIIth) ganglion are derived from the otic placode. In this chapter, we discuss recent findings in the development of these structures and describe the contributions of members of a Forkhead transcription factor family, the Foxi family to their formation. Foxi transcription factors are critical for formation of the otic placode, survival of the branchial arch neural crest, and developmental remodeling of the branchial arch ectoderm.
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Affiliation(s)
- Renée K Edlund
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Onur Birol
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA; Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA.
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PFKFB4 controls embryonic patterning via Akt signalling independently of glycolysis. Nat Commun 2015; 6:5953. [PMID: 25601028 DOI: 10.1038/ncomms6953] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 11/26/2014] [Indexed: 12/25/2022] Open
Abstract
How metabolism regulators play roles during early development remains elusive. Here we show that PFKFB4 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4), a glycolysis regulator, is critical for controlling dorsal ectoderm global patterning in gastrulating frog embryos via a non-glycolytic function. PFKFB4 is required for dorsal ectoderm progenitors to proceed towards more specified fates including neural and non-neural ectoderm, neural crest or placodes. This function is mediated by Akt signalling, a major pathway that integrates cell homeostasis and survival parameters. Restoring Akt signalling rescues the loss of PFKFB4 in vivo. In contrast, glycolysis is not essential for frog development at this stage. Our study reveals the existence of a PFKFB4-Akt checkpoint that links cell homeostasis to the ability of progenitor cells to undergo differentiation, and uncovers glycolysis-independent functions of PFKFB4.
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Whittington N, Cunningham D, Le TK, De Maria D, Silva EM. Sox21 regulates the progression of neuronal differentiation in a dose-dependent manner. Dev Biol 2015; 397:237-47. [PMID: 25448693 PMCID: PMC4325979 DOI: 10.1016/j.ydbio.2014.11.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 11/12/2014] [Indexed: 12/27/2022]
Abstract
Members of the SoxB transcription factor family play critical roles in the regulation of neurogenesis. The SoxB1 proteins are required for the induction and maintenance of a proliferating neural progenitor population in numerous vertebrates, however the role of the SoxB2 protein, Sox21, is less clear due to conflicting results. To clarify the role of Sox21 in neurogenesis, we examined its function in the Xenopus neural plate. Here we report that misexpression of Sox21 expands the neural progenitor domain, and represses neuron formation by binding to Neurogenin (Ngn2) and blocking its function. Conversely, we found that Sox21 is also required for neuron formation, as cells lacking Sox21 undergo cell death and thus are unable to differentiate. Together our data indicate that Sox21 plays more than one role in neurogenesis, where a threshold level is required for cell viability and normal differentiation of neurons, but a higher concentration of Sox21 inhibits neuron formation and instead promotes progenitor maintenance.
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Affiliation(s)
- Niteace Whittington
- Department of Biology, Georgetown University, 37th and O Streets NW, Regents Hall 408, Washington, DC 20057, USA.
| | - Doreen Cunningham
- Department of Biology, Georgetown University, 37th and O Streets NW, Regents Hall 408, Washington, DC 20057, USA.
| | - Thien-Kim Le
- Department of Biology, Georgetown University, 37th and O Streets NW, Regents Hall 408, Washington, DC 20057, USA.
| | - David De Maria
- Department of Biology, Georgetown University, 37th and O Streets NW, Regents Hall 408, Washington, DC 20057, USA.
| | - Elena M Silva
- Department of Biology, Georgetown University, 37th and O Streets NW, Regents Hall 408, Washington, DC 20057, USA.
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Cell adhesion properties of neural stem cells in the chick embryo. In Vitro Cell Dev Biol Anim 2014; 51:507-14. [PMID: 25487674 DOI: 10.1007/s11626-014-9851-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 11/20/2014] [Indexed: 12/21/2022]
Abstract
The nervous system of vertebrates is derived from an early embryonic region referred to as the neural plate. In the chick embryo, the neural plate is populated by neural stem cells specified from the epiblast shortly after the onset of gastrulation. Accompanying the formation of the plate, chondroitin sulfate glycosaminoglycans are expressed in the basal extracellular matrix. We describe in vitro experiments measuring cell adhesion of epiblast cells during the formation of the neural plate. Our findings may suggest that neural stem cells are set apart from non-neural epiblast by changes in relative cell-cell and cell-substrate adhesion. Specifically, changes in cell adhesion separating neural stem cells from the non-neural epiblast may be augmented by the presence of exogenous chondroitin-6-sulfate in the epiblast basal lamina at the time neural progenitors are specified in the epiblast.
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Transcriptome analysis of chicken ES, blastodermal and germ cells reveals that chick ES cells are equivalent to mouse ES cells rather than EpiSC. Stem Cell Res 2014; 14:54-67. [PMID: 25514344 PMCID: PMC4305369 DOI: 10.1016/j.scr.2014.11.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 11/19/2014] [Accepted: 11/24/2014] [Indexed: 12/21/2022] Open
Abstract
Pluripotent Embryonic Stem cell (ESC) lines can be derived from a variety of sources. Mouse lines derived from the early blastocyst and from primordial germ cells (PGCs) can contribute to all somatic lineages and to the germ line, whereas cells from slightly later embryos (EpiSC) no longer contribute to the germ line. In chick, pluripotent ESCs can be obtained from PGCs and from early blastoderms. Established PGC lines and freshly isolated blastodermal cells (cBC) can contribute to both germinal and somatic lineages but established lines from the former (cESC) can only produce somatic cell types. For this reason, cESCs are often considered to be equivalent to mouse EpiSC. To define these cell types more rigorously, we have performed comparative microarray analysis to describe a transcriptomic profile specific for each cell type. This is validated by real time RT-PCR and in situ hybridisation. We find that both cES and cBC cells express classic pluripotency-related genes (including cPOUV/OCT4, NANOG, SOX2/3, KLF2 and SALL4), whereas expression of DAZL, DND1, DDX4 and PIWIL1 defines a molecular signature for germ cells. Surprisingly, contrary to the prevailing view, our results also suggest that cES cells resemble mouse ES cells more closely than mouse EpiSC.
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38
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Can the ‘neuron theory’ be complemented by a universal mechanism for generic neuronal differentiation. Cell Tissue Res 2014; 359:343-84. [DOI: 10.1007/s00441-014-2049-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 10/23/2014] [Indexed: 12/19/2022]
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Freese NH, Lam BA, Staton M, Scott A, Chapman SC. A novel gain-of-function mutation of the proneural IRX1 and IRX2 genes disrupts axis elongation in the Araucana rumpless chicken. PLoS One 2014; 9:e112364. [PMID: 25372603 PMCID: PMC4221472 DOI: 10.1371/journal.pone.0112364] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 10/14/2014] [Indexed: 12/02/2022] Open
Abstract
Axis elongation of the vertebrate embryo involves the generation of cell lineages from posterior progenitor populations. We investigated the molecular mechanism governing axis elongation in vertebrates using the Araucana rumpless chicken. Araucana embryos exhibit a defect in axis elongation, failing to form the terminal somites and concomitant free caudal vertebrae, pygostyle, and associated tissues of the tail. Through whole genome sequencing of six Araucana we have identified a critical 130 kb region, containing two candidate causative SNPs. Both SNPs are proximal to the IRX1 and IRX2 genes, which are required for neural specification. We show that IRX1 and IRX2 are both misexpressed within the bipotential chordoneural hinge progenitor population of Araucana embryos. Expression analysis of BRA and TBX6, required for specification of mesoderm, shows that both are downregulated, whereas SOX2, required for neural patterning, is expressed in ectopic epithelial tissue. Finally, we show downregulation of genes required for the protection and maintenance of the tailbud progenitor population from the effects of retinoic acid. Our results support a model where the disruption in balance of mesoderm and neural fate results in early depletion of the progenitor population as excess neural tissue forms at the expense of mesoderm, leading to too few mesoderm cells to form the terminal somites. Together this cascade of events leads to axis truncation.
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Affiliation(s)
- Nowlan H. Freese
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, United States of America
| | - Brianna A. Lam
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, United States of America
| | - Meg Staton
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Allison Scott
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, United States of America
| | - Susan C. Chapman
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, United States of America
- * E-mail:
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40
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Mandalos N, Rhinn M, Granchi Z, Karampelas I, Mitsiadis T, Economides AN, Dollé P, Remboutsika E. Sox2 acts as a rheostat of epithelial to mesenchymal transition during neural crest development. Front Physiol 2014; 5:345. [PMID: 25309446 PMCID: PMC4162359 DOI: 10.3389/fphys.2014.00345] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/22/2014] [Indexed: 12/19/2022] Open
Abstract
Precise control of self-renewal and differentiation of progenitor cells into the cranial neural crest (CNC) pool ensures proper head development, guided by signaling pathways such as BMPs, FGFs, Shh and Notch. Here, we show that murine Sox2 plays an essential role in controlling progenitor cell behavior during craniofacial development. A “Conditional by Inversion” Sox2 allele (Sox2COIN) has been employed to generate an epiblast ablation of Sox2 function (Sox2EpINV). Sox2EpINV/+(H) haploinsufficient and conditional (Sox2EpINV/mosaic) mutant embryos proceed beyond gastrulation and die around E11. These mutant embryos exhibit severe anterior malformations, with hydrocephaly and frontonasal truncations, which could be attributed to the deregulation of CNC progenitor cells during their epithelial to mesenchymal transition. This irregularity results in an exacerbated and aberrant migration of Sox10+ NCC in the branchial arches and frontonasal process of the Sox2 mutant embryos. These results suggest a novel role for Sox2 as a regulator of the epithelial to mesenchymal transitions (EMT) that are important for the cell flow in the developing head.
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Affiliation(s)
- Nikolaos Mandalos
- Stem Cell Biology Laboratory, Division of Molecular Biology and Genetics, Biomedical Sciences Research Centre "Alexander Fleming" Vari-Attica, Greece
| | - Muriel Rhinn
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM, U964, CNRS, UMR7104, Université de Strasbourg Illkirch, France
| | - Zoraide Granchi
- Orofacial Development and Regeneration Unit, Faculty of Medicine, Institute of Oral Biology, University of Zurich, ZZM Zurich, Switzerland
| | - Ioannis Karampelas
- Stem Cell Biology Laboratory, Division of Molecular Biology and Genetics, Biomedical Sciences Research Centre "Alexander Fleming" Vari-Attica, Greece ; Department of Neurosurgery, University Hospitals Case Medical Center Cleveland, OH, USA
| | - Thimios Mitsiadis
- Orofacial Development and Regeneration Unit, Faculty of Medicine, Institute of Oral Biology, University of Zurich, ZZM Zurich, Switzerland
| | | | - Pascal Dollé
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM, U964, CNRS, UMR7104, Université de Strasbourg Illkirch, France
| | - Eumorphia Remboutsika
- Stem Cell Biology Laboratory, Division of Molecular Biology and Genetics, Biomedical Sciences Research Centre "Alexander Fleming" Vari-Attica, Greece
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Liu YR, Laghari ZA, Novoa CA, Hughes J, Webster JRM, Goodwin PE, Wheatley SP, Scotting PJ. Sox2 acts as a transcriptional repressor in neural stem cells. BMC Neurosci 2014; 15:95. [PMID: 25103589 PMCID: PMC4148960 DOI: 10.1186/1471-2202-15-95] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/30/2014] [Indexed: 12/30/2022] Open
Abstract
Background The transcription factor, Sox2, is central to the behaviour of neural stem cells. It is also one of the key embryonic stem cell factors that, when overexpressed can convert somatic cells into induced pluripotent cells. Although generally studied as a transcriptional activator, recent evidence suggests that it might also repress gene expression. Results We show that in neural stem cells Sox2 represses as many genes as it activates. We found that Sox2 interacts directly with members of the groucho family of corepressors and that repression of several target genes required this interaction. Strikingly, where many of the genes activated by Sox2 encode transcriptional regulators, no such genes were repressed. Finally, we found that a mutant form of Sox2 that was unable to bind groucho was no longer able to inhibit differentiation of neural stem cells to the same extent as the wild type protein. Conclusions These data reveal a major new mechanism of action for this key transcription factor. In the context of our understanding of endogenous stem cells, this highlights the need to determine how such a central regulator can distinguish which genes to activate and which to repress. Electronic supplementary material The online version of this article (doi:10.1186/1471-2202-15-95) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | - Paul J Scotting
- Centre for Genetics and Genomics, School of Life Sciences, Queen's Medical Centre, Nottingham NG7 2UH, England.
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Foxi3 is necessary for the induction of the chick otic placode in response to FGF signaling. Dev Biol 2014; 391:158-69. [PMID: 24780628 DOI: 10.1016/j.ydbio.2014.04.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 03/19/2014] [Accepted: 04/20/2014] [Indexed: 01/06/2023]
Abstract
Vertebrate cranial sensory organs are derived from region at the border of the anterior neural plate called the pre-placodal region (PPR). The otic placode, the anlagen of the inner ear, is induced from PPR ectoderm by FGF signaling. We have previously shown that competence of embryonic ectoderm to respond to FGF signaling during otic placode induction correlates with the expression of PPR genes, but the molecular basis of this competence is poorly understood. Here, we characterize the function of a transcription factor, Foxi3 that is expressed at very early stages in the non-neural ectoderm and later in the PPR of chick embryos. Ablation experiments showed that the underlying hypoblast is necessary for the initiation of Foxi3 expression. Mis-expression of Foxi3 was sufficient to induce markers of non-neural ectoderm such as Dlx5, and the PPR such as Six1 and Eya2. Electroporation of Dlx5, or Six1 together with Eya1 also induced Foxi3, suggesting direct or indirect positive regulation between non-neural ectoderm genes and PPR genes. Knockdown of Foxi3 in chick embryos prevented the induction of otic placode markers, and was able to prevent competent cranial ectoderm from expressing otic markers in response to FGF2. In contrast, Foxi3 expression alone was not sufficient to confer competence to respond to FGF on embryonic ectoderm. Our analysis of PPR and FGF-responsive genes after Foxi3 knockdown at gastrula stages suggests it is not necessary for the expression of PPR genes at these stages, nor for the transduction of FGF signals. The early expression but late requirement for Foxi3 in ear induction suggests it may have some of the properties associated with pioneer transcription factors.
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Blanc S, Ruggiero F, Birot AM, Acloque H, Décimo D, Lerat E, Ohlmann T, Samarut J, Mey A. Subcellular localization of ENS-1/ERNI in chick embryonic stem cells. PLoS One 2014; 9:e92039. [PMID: 24643087 PMCID: PMC3958431 DOI: 10.1371/journal.pone.0092039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 02/19/2014] [Indexed: 11/18/2022] Open
Abstract
The protein of retroviral origin ENS-1/ERNI plays a major role during neural plate development in chick embryos by controlling the activity of the epigenetic regulator HP1γ, but its function in the earlier developmental stages is still unknown. ENS-1/ERNI promoter activity is down-regulated upon differentiation but the resulting protein expression has never been examined. In this study, we present the results obtained with custom-made antibodies to gain further insights into ENS-1 protein expression in Chicken embryonic stem cells (CES) and during their differentiation. First, we show that ENS-1 controls the activity of HP1γ in CES and we examined the context of its interaction with HP1γ. By combining immunofluorescence and western blot analysis we show that ENS-1 is localized in the cytoplasm and in the nucleus, in agreement with its role on gene's promoter activity. During differentiation, ENS-1 decreases in the cytoplasm but not in the nucleus. More precisely, three distinct forms of the ENS-1 protein co-exist in the nucleus and are differently regulated during differentiation, revealing a new level of control of the protein ENS-1. In silico analysis of the Ens-1 gene copies and the sequence of their corresponding proteins indicate that this pattern is compatible with at least three potential regulation mechanisms, each accounting only partially. The results obtained with the anti-ENS-1 antibodies presented here reveal that the regulation of ENS-1 expression in CES is more complex than expected, providing new tracks to explore the integration of ENS-1 in CES cells regulatory networks.
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Affiliation(s)
- Sophie Blanc
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS UMR 5242, INRA USC 1370, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Florence Ruggiero
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS UMR 5242, INRA USC 1370, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Anne-Marie Birot
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS UMR 5242, INRA USC 1370, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Hervé Acloque
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS UMR 5242, INRA USC 1370, Ecole Normale Supérieure de Lyon, Lyon, France
- Laboratoire de Génétique Cellulaire-INRA, ENVT, Castanet Tolosan, France
| | - Didier Décimo
- CIRI, International Center for Infectiology Research, Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Emmanuelle Lerat
- Université de Lyon, Lyon, France; Université Lyon 1, Villeurbanne, France; CNRS, UMR5558, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France
| | - Théophile Ohlmann
- CIRI, International Center for Infectiology Research, Université de Lyon, INSERM U1111, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Jacques Samarut
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS UMR 5242, INRA USC 1370, Ecole Normale Supérieure de Lyon, Lyon, France
- * E-mail: (JS); (AM)
| | - Anne Mey
- Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS UMR 5242, INRA USC 1370, Ecole Normale Supérieure de Lyon, Lyon, France
- * E-mail: (JS); (AM)
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Papanayotou C, De Almeida I, Liao P, Oliveira NMM, Lu SQ, Kougioumtzidou E, Zhu L, Shaw A, Sheng G, Streit A, Yu D, Wah Soong T, Stern CD. Calfacilitin is a calcium channel modulator essential for initiation of neural plate development. Nat Commun 2013; 4:1837. [PMID: 23673622 PMCID: PMC3674269 DOI: 10.1038/ncomms2864] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 04/10/2013] [Indexed: 11/09/2022] Open
Abstract
Calcium fluxes have been implicated in the specification of the vertebrate embryonic nervous system for some time, but how these fluxes are regulated and how they relate to the rest of the neural induction cascade is unknown. Here we describe Calfacilitin, a transmembrane calcium channel facilitator that increases calcium flux by generating a larger window current and slowing inactivation of the L-type CaV1.2 channel. Calfacilitin binds to this channel and is co-expressed with it in the embryo. Regulation of intracellular calcium by Calfacilitin is required for expression of the neural plate specifiers Geminin and Sox2 and for neural plate formation. Loss-of-function of Calfacilitin can be rescued by ionomycin, which increases intracellular calcium. Our results elucidate the role of calcium fluxes in early neural development and uncover a new factor in the modulation of calcium signalling.
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Affiliation(s)
- Costis Papanayotou
- Department of Cell and Developmental Biology, University College London, Gower Street (Anatomy Building), London WC1E 6BT, UK.
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Setting appropriate boundaries: fate, patterning and competence at the neural plate border. Dev Biol 2013; 389:2-12. [PMID: 24321819 DOI: 10.1016/j.ydbio.2013.11.027] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 11/20/2022]
Abstract
The neural crest and craniofacial placodes are two distinct progenitor populations that arise at the border of the vertebrate neural plate. This border region develops through a series of inductive interactions that begins before gastrulation and progressively divide embryonic ectoderm into neural and non-neural regions, followed by the emergence of neural crest and placodal progenitors. In this review, we describe how a limited repertoire of inductive signals-principally FGFs, Wnts and BMPs-set up domains of transcription factors in the border region which establish these progenitor territories by both cross-inhibitory and cross-autoregulatory interactions. The gradual assembly of different cohorts of transcription factors that results from these interactions is one mechanism to provide the competence to respond to inductive signals in different ways, ultimately generating the neural crest and cranial placodes.
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46
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Cattell MV, Garnett AT, Klymkowsky MW, Medeiros DM. A maternally established SoxB1/SoxF axis is a conserved feature of chordate germ layer patterning. Evol Dev 2013; 14:104-15. [PMID: 23016978 DOI: 10.1111/j.1525-142x.2011.00525.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Despite deep evolutionary roots in the metazoa, the gene regulatory network driving germ layer specification is surprisingly labile both between and within phyla. In Xenopus laevis, SoxB1- and SoxF-type transcription factors are intimately involved in germ-layer specification, in part through their regulation of Nodal signaling. However, it is unclear if X. laevis is representative of the ancestral vertebrate condition, as the precise roles of SoxF and SoxB1 in germ-layer specification vary among vertebrates, and there is no evidence that SoxF mediates germ-layer specification in any invertebrate. To better understand the evolution of germ-layer specification in the vertebrate lineage, we analyzed the expression of soxB1 and soxF genes in embryos and larvae of the basal vertebrate lamprey, and the basal chordate amphioxus. We find that both species maternally deposit soxB1 mRNA in the animal pole, soxF mRNA in the vegetal hemisphere, and zygotically express soxB1 and soxF throughout nascent ectoderm and mesendoderm, respectively. We also find that soxF is excluded from the vegetalmost blastomeres in lamprey and that, in contrast to vertebrates, amphioxus does not express soxF in the oral epithelium. In the context of recent work, our results suggest that a maternally established animal/vegetal Sox axis is a deeply conserved feature of chordate development that predates the role of Nodal in vertebrate germ-layer specification. Furthermore, exclusion of this axis from the vegetal pole in lamprey is consistent with the presence of an extraembryonic yolk mass, as has been previously proposed. Finally, conserved expression of SoxF in the forming mouth across the vertebrates, but not in amphioxus, lends support to the idea that the larval amphioxus mouth is nonhomologous to the vertebrate mouth.
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Affiliation(s)
- Maria V Cattell
- Ecology and Evolutionary Biology, University of Colorado-Boulder, CO 80309-0334, USA
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Rogers N, Cheah PS, Szarek E, Banerjee K, Schwartz J, Thomas P. Expression of the murine transcription factor SOX3 during embryonic and adult neurogenesis. Gene Expr Patterns 2013; 13:240-8. [PMID: 23665444 DOI: 10.1016/j.gep.2013.04.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 04/24/2013] [Accepted: 04/26/2013] [Indexed: 11/18/2022]
Abstract
Previous studies have shown that Sox3 is expressed in nascent neuroprogenitor cells and is functionally required in mammals for development of the dorsal telencephalon and hypothalamus. However, Sox3 expression during embryonic and adult neurogenesis has not been examined in detail. Using a SOX3-specific antibody, we show that murine SOX3 expression is maintained throughout telencephalic neurogenesis and is restricted to progenitor cells with neuroepithelial and radial glial morphologies. We also demonstrate that SOX3 is expressed within the adult neurogenic regions and is coexpressed extensively with the neural stem cell marker SOX2 indicating that it is a lifelong marker of neuroprogenitor cells. In contrast to the telencephalon, Sox3 expression within the developing hypothalamus is upregulated in developing neurons and is maintained in a subset of differentiated hypothalamic cells through to adulthood. Together, these data show that Sox3 regulation is region-specific, consistent with it playing distinct biological roles in the dorsal telencephalon and hypothalamus.
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Affiliation(s)
- Nicholas Rogers
- Discipline of Biochemistry, School of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, Australia
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Khan MAF, Soto-Jimenez LM, Howe T, Streit A, Sosinsky A, Stern CD. Computational tools and resources for prediction and analysis of gene regulatory regions in the chick genome. Genesis 2013; 51:311-24. [PMID: 23355428 PMCID: PMC3664090 DOI: 10.1002/dvg.22375] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 01/16/2013] [Accepted: 01/17/2013] [Indexed: 11/07/2022]
Abstract
The discovery of cis-regulatory elements is a challenging problem in bioinformatics, owing to distal locations and context-specific roles of these elements in controlling gene regulation. Here we review the current bioinformatics methodologies and resources available for systematic discovery of cis-acting regulatory elements and conserved transcription factor binding sites in the chick genome. In addition, we propose and make available, a novel workflow using computational tools that integrate CTCF analysis to predict putative insulator elements, enhancer prediction, and TFBS analysis. To demonstrate the usefulness of this computational workflow, we then use it to analyze the locus of the gene Sox2 whose developmental expression is known to be controlled by a complex array of cis-acting regulatory elements. The workflow accurately predicts most of the experimentally verified elements along with some that have not yet been discovered. A web version of the CTCF tool, together with instructions for using the workflow can be accessed from http://toolshed.g2.bx.psu.edu/view/mkhan1980/ctcf_analysis. For local installation of the tool, relevant Perl scripts and instructions are provided in the directory named "code" in the supplementary materials.
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Affiliation(s)
- Mohsin A F Khan
- Department of Cell & Developmental Biology, University College London, London, United Kingdom
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Kharazi A, Levy ML, Visperas MC, Lin CM. Chicken embryonic brain: an in vivo model for verifying neural stem cell potency. J Neurosurg 2013; 119:512-9. [PMID: 23451907 DOI: 10.3171/2013.1.jns12698] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT The multipotency of neural stem cells (NSCs) can be assessed in vitro by detection of stage-specific markers in response to a suitable differentiation signal. This test is frequently used because it is fast and affordable. However, it is not clear how the in vitro potential for multilineage differentiation and stem cell marker expression would reflect the ability of NSCs to engraft into the brain following transplantation. The authors undertook this study to directly compare the in vitro potency and in vivo migration of human NSCs (hNSCs) expanded under conditions of gradually increased concentration of fetal bovine serum (FBS) as a maturation factor. METHODS Human NSCs isolated from fetal brain were propagated in serum free media (SF-hNSCs) and in media containing 0.1% and 0.2% serum. At Passage 4 in tissue culture the NSCs were harvested and either differentiated in vitro or transplanted into the lateral ventricle of chicken embryonic brain at the late stage of its development (Hamburger and Hamilton Stage 26). The in vitro differentiation was evaluated by immunostaining with neural or glial specific markers, and the in vivo migration was assessed using immunohistology. RESULTS The authors found that SF-hNSCs successfully engrafted into the chicken embryonic brain, which correlated with their ability to differentiate in vitro. NSCs grown at as low as 0.1% concentration of FBS failed to demonstrate the robust in vivo migration pattern but still preserved the capability to differentiate in vitro. Furthermore, NSCs generated in media containing a higher concentration of FBS (0.2%) lost both the in vivo engraftment and in vitro differentiation potential. CONCLUSIONS The present study suggests that marker expression and in vitro differentiation assays might not provide adequate information regarding the behavior of NSCs following their transplantation. The in vivo migration following injection into chicken embryonic brain may provide an important assay of the potency of NSCs.
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Affiliation(s)
- Alex Kharazi
- Department of Research and Development, Stemedica Cell Technologies, Inc., San Diego, CA, USA
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Kuo CL, Lam CM, Hewitt JE, Scotting PJ. Formation of the embryonic organizer is restricted by the competitive influences of Fgf signaling and the SoxB1 transcription factors. PLoS One 2013; 8:e57698. [PMID: 23469052 PMCID: PMC3585176 DOI: 10.1371/journal.pone.0057698] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/23/2013] [Indexed: 11/18/2022] Open
Abstract
The organizer is one of the earliest structures to be established during vertebrate development and is crucial to subsequent patterning of the embryo. We have previously shown that the SoxB1 transcription factor, Sox3, plays a central role as a transcriptional repressor of zebrafish organizer gene expression. Recent data suggest that Fgf signaling has a positive influence on organizer formation, but its role remains to be fully elucidated. In order to better understand how Fgf signaling fits into the complex regulatory network that determines when and where the organizer forms, the relationship between the positive effects of Fgf signaling and the repressive effects of the SoxB1 factors must be resolved. This study demonstrates that both fgf3 and fgf8 are required for expression of the organizer genes, gsc and chd, and that SoxB1 factors (Sox3, and the zebrafish specific factors, Sox19a and Sox19b) can repress the expression of both fgf3 and fgf8. However, we also find that these SoxB1 factors inhibit the expression of gsc and chd independently of their repression of fgf expression. We show that ectopic expression of organizer genes induced solely by the inhibition of SoxB1 function is dependent upon the activation of fgf expression. These data allow us to describe a comprehensive signaling network in which the SoxB1 factors restrict organizer formation by inhibiting Fgf, Nodal and Wnt signaling, as well as independently repressing the targets of that signaling. The organizer therefore forms only where Nodal-induced Fgf signaling overlaps with Wnt signaling and the SoxB1 proteins are absent.
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Affiliation(s)
- Cheng-Liang Kuo
- Centre for Genetics and Genomics, School of Biology, University of Nottingham, QMC, Nottingham, United Kingdom
| | - Chi Man Lam
- Centre for Genetics and Genomics, School of Biology, University of Nottingham, QMC, Nottingham, United Kingdom
| | - Jane E. Hewitt
- Centre for Genetics and Genomics, School of Biology, University of Nottingham, QMC, Nottingham, United Kingdom
| | - Paul J. Scotting
- Centre for Genetics and Genomics, School of Biology, University of Nottingham, QMC, Nottingham, United Kingdom
- * E-mail:
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