1
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Rao SB, Brundu F, Chen Y, Sun Y, Zhu H, Shprintzen RJ, Tomer R, Rabadan R, Leong KW, Markx S, Xu B, Gogos JA. Aberrant pace of cortical neuron development in brain organoids from patients with 22q11.2 deletion syndrome and schizophrenia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.04.557612. [PMID: 37873382 PMCID: PMC10592956 DOI: 10.1101/2023.10.04.557612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Adults and children afflicted with the 22q11.2 deletion syndrome (22q11.2DS) exhibit cognitive, social, and emotional impairments, and are at significantly heightened risk for schizophrenia (SCZ). The impact of this deletion on early human brain development, however, has remained unclear. Here we harness organoid models of the developing human cerebral cortex, cultivated from subjects with 22q11.2DS and SCZ, as well as unaffected control samples, to identify cell-type-specific developmental abnormalities arising from this genomic lesion. Leveraging single-cell RNA-sequencing in conjunction with experimental validation, we find that the loss of genes within the 22q11.2 locus leads to a delayed development of cortical neurons. This compromised development was reflected in an elevated proportion of actively proliferating neural progenitor cells, coupled with a decreased fraction of more mature neurons. Furthermore, we identify perturbed molecular imprints linked to neuronal maturation, observe the presence of sparser neurites, and note a blunted amplitude in glutamate-induced Ca2+ transients. The aberrant transcription program underlying impaired development contains molecular signatures significantly enriched in neuropsychiatric genetic liability. MicroRNA profiling and target gene investigation suggest that microRNA dysregulation may drive perturbations of genes governing the pace at which maturation unfolds. Using protein-protein interaction network analysis we define complementary effects stemming from additional genes residing within the deleted locus. Our study uncovers reproducible neurodevelopmental and molecular alterations due to 22q11.2 deletions. These findings have the potential to facilitate disease modeling and promote the pursuit of therapeutic interventions.
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2
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Caranica C, Lu M. A data-driven optimization method for coarse-graining gene regulatory networks. iScience 2023; 26:105927. [PMID: 36698721 PMCID: PMC9868542 DOI: 10.1016/j.isci.2023.105927] [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: 08/09/2022] [Revised: 12/19/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
One major challenge in systems biology is to understand how various genes in a gene regulatory network (GRN) collectively perform their functions and control network dynamics. This task becomes extremely hard to tackle in the case of large networks with hundreds of genes and edges, many of which have redundant regulatory roles and functions. The existing methods for model reduction usually require the detailed mathematical description of dynamical systems and their corresponding kinetic parameters, which are often not available. Here, we present a data-driven method for coarse-graining large GRNs, named SacoGraci, using ensemble-based mathematical modeling, dimensionality reduction, and gene circuit optimization by Markov Chain Monte Carlo methods. SacoGraci requires network topology as the only input and is robust against errors in GRNs. We benchmark and demonstrate its usage with synthetic, literature-based, and bioinformatics-derived GRNs. We hope SacoGraci will enhance our ability to model the gene regulation of complex biological systems.
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Affiliation(s)
- Cristian Caranica
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA,Center for Theoretical Biological Physics, Northeastern University, Boston, MA 02115, USA
| | - Mingyang Lu
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA,Center for Theoretical Biological Physics, Northeastern University, Boston, MA 02115, USA,The Jackson Laboratory, Bar Harbor, ME 04609, USA,Corresponding author
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3
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Bartlett T. Fusion of single-cell transcriptome and DNA-binding data, for genomic network inference in cortical development. BMC Bioinformatics 2021; 22:301. [PMID: 34088262 PMCID: PMC8176738 DOI: 10.1186/s12859-021-04201-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 05/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Network models are well-established as very useful computational-statistical tools in cell biology. However, a genomic network model based only on gene expression data can, by definition, only infer gene co-expression networks. Hence, in order to infer gene regulatory patterns, it is necessary to also include data related to binding of regulatory factors to DNA. RESULTS We propose a new dynamic genomic network model, for inferring patterns of genomic regulatory influence in dynamic processes such as development. Our model fuses experiment-specific gene expression data with publicly available DNA-binding data. The method we propose is computationally efficient, and can be applied to genome-wide data with tens of thousands of transcripts. Thus, our method is well suited for use as an exploratory tool for genome-wide data. We apply our method to data from human fetal cortical development, and our findings confirm genomic regulatory patterns which are recognised as being fundamental to neuronal development. CONCLUSIONS Our method provides a mathematical/computational toolbox which, when coupled with targeted experiments, will reveal and confirm important new functional genomic regulatory processes in mammalian development.
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Affiliation(s)
- Thomas Bartlett
- University College London, Gower Street, London, WC1E 6BT, UK.
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4
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Hadjivasiliou Z, Moore RE, McIntosh R, Galea GL, Clarke JDW, Alexandre P. Basal Protrusions Mediate Spatiotemporal Patterns of Spinal Neuron Differentiation. Dev Cell 2020; 49:907-919.e10. [PMID: 31211994 PMCID: PMC6584357 DOI: 10.1016/j.devcel.2019.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 02/26/2019] [Accepted: 05/20/2019] [Indexed: 12/22/2022]
Abstract
During early spinal cord development, neurons of particular subtypes differentiate with a sparse periodic pattern while later neurons differentiate in the intervening space to eventually produce continuous columns of similar neurons. The mechanisms that regulate this spatiotemporal pattern are unknown. In vivo imaging in zebrafish reveals that differentiating spinal neurons transiently extend two long protrusions along the basal surface of the spinal cord before axon initiation. These protrusions express Delta protein, consistent with the hypothesis they influence Notch signaling at a distance of several cell diameters. Experimental reduction of Laminin expression leads to smaller protrusions and shorter distances between differentiating neurons. The experimental data and a theoretical model support the proposal that neuronal differentiation pattern is regulated by transient basal protrusions that deliver temporally controlled lateral inhibition mediated at a distance. This work uncovers a stereotyped protrusive activity of newborn neurons that organize long-distance spatiotemporal patterning of differentiation.
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Affiliation(s)
- Zena Hadjivasiliou
- Department of Biochemistry, Science II, University of Geneva, Geneva, Switzerland; Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1N 1EH, UK
| | - Rachel E Moore
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE1 1UL, UK
| | - Rebecca McIntosh
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE1 1UL, UK; Developmental Biology and Cancer, UCL GOS Institute of Child Health, London WC1N 1EH, UK
| | - Gabriel L Galea
- Developmental Biology and Cancer, UCL GOS Institute of Child Health, London WC1N 1EH, UK
| | - Jonathan D W Clarke
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London SE1 1UL, UK.
| | - Paula Alexandre
- Developmental Biology and Cancer, UCL GOS Institute of Child Health, London WC1N 1EH, UK.
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5
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Young RM, Ewan KB, Ferrer VP, Allende ML, Godovac-Zimmermann J, Dale TC, Wilson SW. Developmentally regulated Tcf7l2 splice variants mediate transcriptional repressor functions during eye formation. eLife 2019; 8:e51447. [PMID: 31829936 PMCID: PMC6908431 DOI: 10.7554/elife.51447] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022] Open
Abstract
Tcf7l2 mediates Wnt/β-Catenin signalling during development and is implicated in cancer and type-2 diabetes. The mechanisms by which Tcf7l2 and Wnt/β-Catenin signalling elicit such a diversity of biological outcomes are poorly understood. Here, we study the function of zebrafish tcf7l2alternative splice variants and show that only variants that include exon five or an analogous human tcf7l2 variant can effectively provide compensatory repressor function to restore eye formation in embryos lacking tcf7l1a/tcf7l1b function. Knockdown of exon five specific tcf7l2 variants in tcf7l1a mutants also compromises eye formation, and these variants can effectively repress Wnt pathway activity in reporter assays using Wnt target gene promoters. We show that the repressive activities of exon5-coded variants are likely explained by their interaction with Tle co-repressors. Furthermore, phosphorylated residues in Tcf7l2 coded exon5 facilitate repressor activity. Our studies suggest that developmentally regulated splicing of tcf7l2 can influence the transcriptional output of the Wnt pathway.
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Affiliation(s)
- Rodrigo M Young
- Department of Cell and Developmental BiologyUCLLondonUnited Kingdom
| | - Kenneth B Ewan
- School of Bioscience, Cardiff UniversityCardiffUnited Kingdom
| | | | - Miguel L Allende
- FONDAP Center for Genome Regulation, Facultad de Ciencias, Universidad de ChileSantiagoChile
| | | | - Trevor C Dale
- School of Bioscience, Cardiff UniversityCardiffUnited Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental BiologyUCLLondonUnited Kingdom
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6
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Young RM, Hawkins TA, Cavodeassi F, Stickney HL, Schwarz Q, Lawrence LM, Wierzbicki C, Cheng BYL, Luo J, Ambrosio EM, Klosner A, Sealy IM, Rowell J, Trivedi CA, Bianco IH, Allende ML, Busch-Nentwich EM, Gestri G, Wilson SW. Compensatory growth renders Tcf7l1a dispensable for eye formation despite its requirement in eye field specification. eLife 2019; 8:e40093. [PMID: 30777146 PMCID: PMC6380838 DOI: 10.7554/elife.40093] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 01/26/2019] [Indexed: 12/18/2022] Open
Abstract
The vertebrate eye originates from the eye field, a domain of cells specified by a small number of transcription factors. In this study, we show that Tcf7l1a is one such transcription factor that acts cell-autonomously to specify the eye field in zebrafish. Despite the much-reduced eye field in tcf7l1a mutants, these fish develop normal eyes revealing a striking ability of the eye to recover from a severe early phenotype. This robustness is not mediated through genetic compensation at neural plate stage; instead, the smaller optic vesicle of tcf7l1a mutants shows delayed neurogenesis and continues to grow until it achieves approximately normal size. Although the developing eye is robust to the lack of Tcf7l1a function, it is sensitised to the effects of additional mutations. In support of this, a forward genetic screen identified mutations in hesx1, cct5 and gdf6a, which give synthetically enhanced eye specification or growth phenotypes when in combination with the tcf7l1a mutation.
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Affiliation(s)
- Rodrigo M Young
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Thomas A Hawkins
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Florencia Cavodeassi
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Heather L Stickney
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Quenten Schwarz
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Lisa M Lawrence
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Claudia Wierzbicki
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Bowie YL Cheng
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Jingyuan Luo
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | | | - Allison Klosner
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Ian M Sealy
- Wellcome Sanger InstituteWellcome Genome CampusHinxtonUnited Kingdom
- Department of MedicineUniversity of CambridgeCambridgeUnited Kingdom
| | - Jasmine Rowell
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Chintan A Trivedi
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Isaac H Bianco
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Miguel L Allende
- Center for Genome RegulationFacultad de Ciencias, Universidad de ChileSantiagoChile
| | - Elisabeth M Busch-Nentwich
- Wellcome Sanger InstituteWellcome Genome CampusHinxtonUnited Kingdom
- Department of MedicineUniversity of CambridgeCambridgeUnited Kingdom
| | - Gaia Gestri
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental BiologyUniversity College LondonLondonUnited Kingdom
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7
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Ramakrishnan AB, Sinha A, Fan VB, Cadigan KM. The Wnt Transcriptional Switch: TLE Removal or Inactivation? Bioessays 2017; 40. [PMID: 29250807 DOI: 10.1002/bies.201700162] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/12/2017] [Indexed: 01/06/2023]
Abstract
Many targets of the Wnt/β-catenin signaling pathway are regulated by TCF transcription factors, which play important roles in animal development, stem cell biology, and oncogenesis. TCFs can regulate Wnt targets through a "transcriptional switch," repressing gene expression in unstimulated cells and promoting transcription upon Wnt signaling. However, it is not clear whether this switch mechanism is a general feature of Wnt gene regulation or limited to a subset of Wnt targets. Co-repressors of the TLE family are known to contribute to the repression of Wnt targets in the absence of signaling, but how they are inactivated or displaced by Wnt signaling is poorly understood. In this mini-review, we discuss several recent reports that address the prevalence and molecular mechanisms of the Wnt transcription switch, including the finding of Wnt-dependent ubiquitination/inactivation of TLEs. Together, these findings highlight the growing complexity of the regulation of gene expression by the Wnt pathway.
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Affiliation(s)
| | - Abhishek Sinha
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048
| | - Vinson B Fan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048
| | - Ken M Cadigan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109-1048
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8
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Hahn C, Genner MJ, Turner GF, Joyce DA. The genomic basis of cichlid fish adaptation within the deepwater "twilight zone" of Lake Malawi. Evol Lett 2017; 1:184-198. [PMID: 30283648 PMCID: PMC6124600 DOI: 10.1002/evl3.20] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 06/01/2017] [Accepted: 07/11/2017] [Indexed: 12/21/2022] Open
Abstract
Deepwater environments are characterized by low levels of available light at narrow spectra, great hydrostatic pressure, and low levels of dissolved oxygen—conditions predicted to exert highly specific selection pressures. In Lake Malawi over 800 cichlid species have evolved, and this adaptive radiation extends into the “twilight zone” below 50 m. We use population‐level RAD‐seq data to investigate whether four endemic deepwater species (Diplotaxodon spp.) have experienced divergent selection within this environment. We identify candidate genes including regulators of photoreceptor function, photopigments, lens morphology, and haemoglobin, many not previously implicated in cichlid adaptive radiations. Colocalization of functionally linked genes suggests coadapted “supergene” complexes. Comparisons of Diplotaxodon to the broader Lake Malawi radiation using genome resequencing data revealed functional substitutions and signatures of positive selection in candidate genes. Our data provide unique insights into genomic adaptation within deepwater habitats, and suggest genome‐level specialization for life at depth as an important process in cichlid radiation.
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Affiliation(s)
- Christoph Hahn
- Evolutionary and Environmental Genomics Group (@EvoHull), School of Environmental Sciences University of Hull Hull HU5 7RX United Kingdom.,Institute of Zoology University of Graz A-8010 Graz Austria
| | - Martin J Genner
- School of Biological Sciences University of Bristol Bristol Life Sciences Building, 24 Tyndall Avenue Bristol BS8 1TQ United Kingdom
| | - George F Turner
- School of Biological Sciences Bangor University Bangor Gwynedd LL57 2UW Wales United Kingdom
| | - Domino A Joyce
- Evolutionary and Environmental Genomics Group (@EvoHull), School of Environmental Sciences University of Hull Hull HU5 7RX United Kingdom
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9
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Abstract
Wnt/β-catenin signaling is highly conserved throughout metazoans, is required for numerous essential events in development, and serves as a stem cell niche signal in many contexts. Misregulation of the pathway is linked to several human pathologies, most notably cancer. Wnt stimulation results in stabilization and nuclear import of β-catenin, which then acts as a transcriptional co-activator. Transcription factors of the T-cell family (TCF) are the best-characterized nuclear binding partners of β-catenin and mediators of Wnt gene regulation. This review provides an update on what is known about the transcriptional activation of Wnt target genes, highlighting recent work that modifies the conventional model. Wnt/β-catenin signaling regulates genes in a highly context-dependent manner, and the role of other signaling pathways and TCF co-factors in this process will be discussed. Understanding Wnt gene regulation has served to elucidate many biological roles of the pathway, and we will use examples from stem cell biology, metabolism, and evolution to illustrate some of the rich Wnt biology that has been uncovered.
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Affiliation(s)
| | - Ken M Cadigan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
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10
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Ku AT, Shaver TM, Rao AS, Howard JM, Rodriguez CN, Miao Q, Garcia G, Le D, Yang D, Borowiak M, Cohen DN, Chitsazzadeh V, Diwan AH, Tsai KY, Nguyen H. TCF7L1 promotes skin tumorigenesis independently of β-catenin through induction of LCN2. eLife 2017; 6:e23242. [PMID: 28467300 PMCID: PMC5438253 DOI: 10.7554/elife.23242] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 04/29/2017] [Indexed: 12/14/2022] Open
Abstract
The transcription factor TCF7L1 is an embryonic stem cell signature gene that is upregulated in multiple aggressive cancer types, but its role in skin tumorigenesis has not yet been defined. Here we document TCF7L1 upregulation in skin squamous cell carcinoma (SCC) and demonstrate that TCF7L1 overexpression increases tumor incidence, tumor multiplicity, and malignant progression in the chemically induced mouse model of skin SCC. Additionally, we show that downregulation of TCF7L1 and its paralogue TCF7L2 reduces tumor growth in a xenograft model of human skin SCC. Using separation-of-function mutants, we show that TCF7L1 promotes tumor growth, enhances cell migration, and overrides oncogenic RAS-induced senescence independently of its interaction with β-catenin. Through transcriptome profiling and combined gain- and loss-of-function studies, we identified LCN2 as a major downstream effector of TCF7L1 that drives tumor growth. Our findings establish a tumor-promoting role for TCF7L1 in skin and elucidate the mechanisms underlying its tumorigenic capacity.
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Affiliation(s)
- Amy T Ku
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, United States
| | - Timothy M Shaver
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
| | - Ajay S Rao
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
| | - Jeffrey M Howard
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
| | - Christine N Rodriguez
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States
| | - Qi Miao
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
| | - Gloria Garcia
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
| | - Diep Le
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
| | - Diane Yang
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States
| | - Malgorzata Borowiak
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- McNair Medical Institute, Baylor College of Medicine, Houston, United States
| | - Daniel N Cohen
- Department of Pathology and Immunology, Michael E. DeBakey VA Medical Center, Baylor College of Medicine, Houston, United States
| | - Vida Chitsazzadeh
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, Houston, United States
| | - Abdul H Diwan
- Department of Dermatology, Baylor College of Medicine, Houston, United States
| | - Kenneth Y Tsai
- Department of Tumor Biology, Moffitt Cancer Center, Tampa, United States
- Department of Anatomic Pathology, Moffitt Cancer Center, Tampa, United States
| | - Hoang Nguyen
- Stem Cell and Regenerative Medicine Center, Baylor College of Medicine, Houston, United States
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, United States
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, United States
- Program in Developmental Biology, Baylor College of Medicine, Houston, United States
- Department of Dermatology, Baylor College of Medicine, Houston, United States
- Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, United States
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11
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Juárez-Morales JL, Martinez-De Luna RI, Zuber ME, Roberts A, Lewis KE. Zebrafish transgenic constructs label specific neurons in Xenopus laevis spinal cord and identify frog V0v spinal neurons. Dev Neurobiol 2017; 77:1007-1020. [PMID: 28188691 DOI: 10.1002/dneu.22490] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 01/26/2017] [Accepted: 02/08/2017] [Indexed: 12/19/2022]
Abstract
A correctly functioning spinal cord is crucial for locomotion and communication between body and brain but there are fundamental gaps in our knowledge of how spinal neuronal circuitry is established and functions. To understand the genetic program that regulates specification and functions of this circuitry, we need to connect neuronal molecular phenotypes with physiological analyses. Studies using Xenopus laevis tadpoles have increased our understanding of spinal cord neuronal physiology and function, particularly in locomotor circuitry. However, the X. laevis tetraploid genome and long generation time make it difficult to investigate how neurons are specified. The opacity of X. laevis embryos also makes it hard to connect functional classes of neurons and the genes that they express. We demonstrate here that Tol2 transgenic constructs using zebrafish enhancers that drive expression in specific zebrafish spinal neurons label equivalent neurons in X. laevis and that the incorporation of a Gal4:UAS amplification cassette enables cells to be observed in live X. laevis tadpoles. This technique should enable the molecular phenotypes, morphologies and physiologies of distinct X. laevis spinal neurons to be examined together in vivo. We have used an islet1 enhancer to label Rohon-Beard sensory neurons and evx enhancers to identify V0v neurons, for the first time, in X. laevis spinal cord. Our work demonstrates the homology of spinal cord circuitry in zebrafish and X. laevis, suggesting that future work could combine their relative strengths to elucidate a more complete picture of how vertebrate spinal cord neurons are specified, and function to generate behavior. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 1007-1020, 2017.
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Affiliation(s)
- José L Juárez-Morales
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244.,Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, United Kingdom
| | - Reyna I Martinez-De Luna
- The Center for Vision Research, Department of Ophthalmology, SUNY Upstate Medical University, Institute for Human Performance, 505 Irving Ave. Syracuse, New York, 13210
| | - Michael E Zuber
- The Center for Vision Research, Department of Ophthalmology, SUNY Upstate Medical University, Institute for Human Performance, 505 Irving Ave. Syracuse, New York, 13210
| | - Alan Roberts
- School of Biological Sciences, Bristol University, 24 Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Katharine E Lewis
- Department of Biology, Syracuse University, 107 College Place, Syracuse, New York, 13244
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12
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Ghosh S, Hui SP. Regeneration of Zebrafish CNS: Adult Neurogenesis. Neural Plast 2016; 2016:5815439. [PMID: 27382491 PMCID: PMC4921647 DOI: 10.1155/2016/5815439] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022] Open
Abstract
Regeneration in the animal kingdom is one of the most fascinating problems that have allowed scientists to address many issues of fundamental importance in basic biology. However, we came to know that the regenerative capability may vary across different species. Among vertebrates, fish and amphibians are capable of regenerating a variety of complex organs through epimorphosis. Zebrafish is an excellent animal model, which can repair several organs like damaged retina, severed spinal cord, injured brain and heart, and amputated fins. The focus of the present paper is on spinal cord regeneration in adult zebrafish. We intend to discuss our current understanding of the cellular and molecular mechanism(s) that allows formation of proliferating progenitors and controls neurogenesis, which involve changes in epigenetic and transcription programs. Unlike mammals, zebrafish retains radial glia, a nonneuronal cell type in their adult central nervous system. Injury induced proliferation involves radial glia which proliferate, transcribe embryonic genes, and can give rise to new neurons. Recent technological development of exquisite molecular tools in zebrafish, such as cell ablation, lineage analysis, and novel and substantial microarray, together with advancement in stem cell biology, allowed us to investigate how progenitor cells contribute to the generation of appropriate structures and various underlying mechanisms like reprogramming.
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Affiliation(s)
- Sukla Ghosh
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Subhra Prakash Hui
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
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13
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Mathews CA, Stern JS. The First World Congress on Tourette Syndrome and Tic Disorders: Controversies and Hot Topics in Etiology and Treatment. Front Neurosci 2016; 10:246. [PMID: 27375411 PMCID: PMC4894886 DOI: 10.3389/fnins.2016.00246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/18/2016] [Indexed: 12/27/2022] Open
Abstract
The first World Congress on Tourette Syndrome and Tic Disorders was held in London, June 2016 by the Tourette Association of America, Tourettes Action (UK), and the European Society for the Study of Tourette Syndrome. Presentations arising from large-scale collaborative projects were an important component of the scientific programme. This article focuses on areas raised in the hot topics session and two moderated debates, which covered emerging research in etiology and treatment. The hot topics ranged across genetics, arguably including the first confirmed Tourette Syndrome (TS) susceptibility gene NRXN1, neurocognition, and neurophysiology, including the possibility of a neurocognitive endophenotype for TS and the use of depth and cortical surface electrodes to investigate the neurophysiology of tics on the background of the evolving field of deep brain stimulation (DBS), to novel treatment approaches such as dental orthotics and an online behavioral intervention. The debates aired controversies in treatment; pharmacotherapy vs. behavioral treatment and the place of medical cannabinoids. These sessions demonstrate the vibrancy of a field that has considerably expanded in the last decade, the significant progress that has been made, and the direction that some of the most fruitful next phases of research will take.
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Affiliation(s)
- Carol A Mathews
- Department of Psychiatry, College of Medicine, University of Florida Gainesville, Florida, USA
| | - Jeremy S Stern
- Department of Neurology, St George's University of London London, UK
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14
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Gaston-Massuet C, McCabe MJ, Scagliotti V, Young RM, Carreno G, Gregory LC, Jayakody SA, Pozzi S, Gualtieri A, Basu B, Koniordou M, Wu CI, Bancalari RE, Rahikkala E, Veijola R, Lopponen T, Graziola F, Turton J, Signore M, Mousavy Gharavy SN, Charolidi N, Sokol SY, Andoniadou CL, Wilson SW, Merrill BJ, Dattani MT, Martinez-Barbera JP. Transcription factor 7-like 1 is involved in hypothalamo-pituitary axis development in mice and humans. Proc Natl Acad Sci U S A 2016; 113:E548-57. [PMID: 26764381 PMCID: PMC4747739 DOI: 10.1073/pnas.1503346113] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aberrant embryonic development of the hypothalamus and/or pituitary gland in humans results in congenital hypopituitarism (CH). Transcription factor 7-like 1 (TCF7L1), an important regulator of the WNT/β-catenin signaling pathway, is expressed in the developing forebrain and pituitary gland, but its role during hypothalamo-pituitary (HP) axis formation or involvement in human CH remains elusive. Using a conditional genetic approach in the mouse, we first demonstrate that TCF7L1 is required in the prospective hypothalamus to maintain normal expression of the hypothalamic signals involved in the induction and subsequent expansion of Rathke's pouch progenitors. Next, we reveal that the function of TCF7L1 during HP axis development depends exclusively on the repressing activity of TCF7L1 and does not require its interaction with β-catenin. Finally, we report the identification of two independent missense variants in human TCF7L1, p.R92P and p.R400Q, in a cohort of patients with forebrain and/or pituitary defects. We demonstrate that these variants exhibit reduced repressing activity in vitro and in vivo relative to wild-type TCF7L1. Together, our data provide support for a conserved molecular function of TCF7L1 as a transcriptional repressor during HP axis development in mammals and identify variants in this transcription factor that are likely to contribute to the etiology of CH.
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Affiliation(s)
- Carles Gaston-Massuet
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Mark J McCabe
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Valeria Scagliotti
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Rodrigo M Young
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Gabriela Carreno
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Louise C Gregory
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Sujatha A Jayakody
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Sara Pozzi
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Angelica Gualtieri
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - Basudha Basu
- Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029
| | - Markela Koniordou
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Chun-I Wu
- Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, Illinois, IL 60607
| | - Rodrigo E Bancalari
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Elisa Rahikkala
- Research Unit for Pediatrics, Dermatology, Clinical Genetics, Obstetrics and Gynecology (PEDEGO) and Medical Research Center (MRC) Oulu, University of Oulu, FIN-90029, Oulu, Finland; Department of Clinical Genetics, Oulu University Hospital, FIN-90029, Oulu, Finland
| | - Riitta Veijola
- Department of Pediatrics, PEDEGO and MRC Oulu, Oulu University Hospital, University of Oulu, FIN-90014, Oulu, Finland
| | - Tuija Lopponen
- Department of Child Neurology, Kuopio University Hospital, FIN 70029, Kuopio, Finland
| | - Federica Graziola
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, United Kingdom
| | - James Turton
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Massimo Signore
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Seyedeh Neda Mousavy Gharavy
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Nicoletta Charolidi
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Sergei Y Sokol
- Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029
| | - Cynthia Lilian Andoniadou
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom
| | - Stephen W Wilson
- Department of Cell and Developmental Biology, University College London, London WC1E 6BT, United Kingdom
| | - Bradley J Merrill
- Department of Biochemistry and Molecular Genetics, University of Illinois, Chicago, Illinois, IL 60607
| | - Mehul T Dattani
- Genetics and Epigenetics in Health and Disease Section, Genetics and Genomic Medicine Programme, University College London Institute of Child Health, London WC1N 1EH, United Kingdom
| | - Juan Pedro Martinez-Barbera
- Birth Defects Research Centre, Developmental Biology and Cancer Programme, University College London Institute of Child Health, London, WC1N 1EH, United Kingdom;
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Tcf3 promotes cell migration and wound repair through regulation of lipocalin 2. Nat Commun 2014; 5:4088. [PMID: 24909826 PMCID: PMC4052366 DOI: 10.1038/ncomms5088] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/09/2014] [Indexed: 01/25/2023] Open
Abstract
Cell migration is an integral part of re-epithelialization during skin wound healing, a complex process involving molecular controls that are still largely unknown. Here we identify a novel role for Tcf3, an essential transcription factor regulating embryonic and adult skin stem cell functions, as a key effector of epidermal wound repair. We show that Tcf3 is upregulated in skin wounds and that Tcf3 overexpression accelerates keratinocyte migration and skin wound healing. We also identify Stat3 as an upstream regulator of Tcf3. We show that the pro-migration effects of Tcf3 are non-cell autonomous and occur independently of its ability to interact with β-catenin. Finally, we identify lipocalin-2 as the key secreted factor downstream of Tcf3 that promotes cell migration in vitro and wound healing in vivo. Our findings provide new insights into the molecular controls of wound-associated cell migration and identify potential therapeutic targets for the treatment of defective wound repair.
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Kuwahara A, Sakai H, Xu Y, Itoh Y, Hirabayashi Y, Gotoh Y. Tcf3 represses Wnt-β-catenin signaling and maintains neural stem cell population during neocortical development. PLoS One 2014; 9:e94408. [PMID: 24832538 PMCID: PMC4022625 DOI: 10.1371/journal.pone.0094408] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/15/2014] [Indexed: 01/02/2023] Open
Abstract
During mouse neocortical development, the Wnt–β-catenin signaling pathway plays essential roles in various phenomena including neuronal differentiation and proliferation of neural precursor cells (NPCs). Production of the appropriate number of neurons without depletion of the NPC population requires precise regulation of the balance between differentiation and maintenance of NPCs. However, the mechanism that suppresses Wnt signaling to prevent premature neuronal differentiation of NPCs is poorly understood. We now show that the HMG box transcription factor Tcf3 (also known as Tcf7l1) contributes to this mechanism. Tcf3 is highly expressed in undifferentiated NPCs in the mouse neocortex, and its expression is reduced in intermediate neuronal progenitors (INPs) committed to the neuronal fate. We found Tcf3 to be a repressor of Wnt signaling in neocortical NPCs in a reporter gene assay. Tcf3 bound to the promoter of the proneural bHLH gene Neurogenin1 (Neurog1) and repressed its expression. Consistent with this, Tcf3 repressed neuronal differentiation and increased the self-renewal activity of NPCs. We also found that Wnt signal stimulation reduces the level of Tcf3, and increases those of Tcf1 (also known as Tcf7) and Lef1, positive mediators of Wnt signaling, in NPCs. Together, these results suggest that Tcf3 antagonizes Wnt signaling in NPCs, thereby maintaining their undifferentiated state in the neocortex and that Wnt signaling promotes the transition from Tcf3-mediated repression to Tcf1/Lef1-mediated enhancement of Wnt signaling, constituting a positive feedback loop that facilitates neuronal differentiation.
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Affiliation(s)
- Atsushi Kuwahara
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Sakai
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yuanjiang Xu
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yasuhiro Itoh
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yusuke Hirabayashi
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
- * E-mail:
| | - Yukiko Gotoh
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
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Beck AP, Watt RM, Bonner J. Dissection and lateral mounting of zebrafish embryos: analysis of spinal cord development. J Vis Exp 2014:e50703. [PMID: 24637734 PMCID: PMC4140612 DOI: 10.3791/50703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The zebrafish spinal cord is an effective investigative model for nervous system research for several reasons. First, genetic, transgenic and gene knockdown approaches can be utilized to examine the molecular mechanisms underlying nervous system development. Second, large clutches of developmentally synchronized embryos provide large experimental sample sizes. Third, the optical clarity of the zebrafish embryo permits researchers to visualize progenitor, glial, and neuronal populations. Although zebrafish embryos are transparent, specimen thickness can impede effective microscopic visualization. One reason for this is the tandem development of the spinal cord and overlying somite tissue. Another reason is the large yolk ball, which is still present during periods of early neurogenesis. In this article, we demonstrate microdissection and removal of the yolk in fixed embryos, which allows microscopic visualization while preserving surrounding somite tissue. We also demonstrate semipermanent mounting of zebrafish embryos. This permits observation of neurodevelopment in the dorso-ventral and anterior-posterior axes, as it preserves the three-dimensionality of the tissue.
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18
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Sorrell MRJ, Dohn TE, D'Aniello E, Waxman JS. Tcf7l1 proteins cell autonomously restrict cardiomyocyte and promote endothelial specification in zebrafish. Dev Biol 2013; 380:199-210. [PMID: 23707897 DOI: 10.1016/j.ydbio.2013.05.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 05/12/2013] [Accepted: 05/13/2013] [Indexed: 11/24/2022]
Abstract
Tcf7l1 (formerly Tcf3) proteins are conserved transcription factors whose function as transcriptional repressors is relieved through interactions with β-catenin. Although the functions of Tcf7l1 proteins have been studied in many developmental contexts, whether this conserved mediator of Wnt signaling is required for appropriate cardiomyocyte (CM) development has not been investigated. We find that Tcf7l1 proteins are necessary during two developmental periods to limit CM number in zebrafish embryos: prior to gastrulation and after the initial wave of CM differentiation. In contrast to partially redundant roles in anterior neural patterning, we find that Tcf7l1a and Tcf7l1b have non-redundant functions with respect to restricting CM specification during anterior mesodermal patterning, suggesting that between the two zebrafish Tcf7l1 paralogs there is a limit to the transcriptional repression provided during early CM specification. Using cell transplantation experiments, we determine that the Tcf7l1 paralogs are required cell autonomously to restrict CM specification and promote endothelial cell (EC) specification, which is overtly similar to the ability of Wnt signaling to direct a transformation between these progenitors in embryonic stem cells. Therefore, these results argue that during anterior-posterior patterning of the mesoderm Tcf7l1 proteins are cell autonomously required to limit Wnt signaling, which balances CM and EC progenitor specification within the anterior lateral plate mesoderm. This study expands our understanding of the in vivo developmental requirements of Tcf7l1 proteins and the mechanisms directing CM development in vertebrates.
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Affiliation(s)
- Mollie R J Sorrell
- Molecular Cardiovascular Biology Division and The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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19
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Abstract
The Wnt pathway is a major embryonic signaling pathway that controls cell proliferation, cell fate, and body-axis determination in vertebrate embryos. Soon after egg fertilization, Wnt pathway components play a role in microtubule-dependent dorsoventral axis specification. Later in embryogenesis, another conserved function of the pathway is to specify the anteroposterior axis. The dual role of Wnt signaling in Xenopus and zebrafish embryos is regulated at different developmental stages by distinct sets of Wnt target genes. This review highlights recent progress in the discrimination of different signaling branches and the identification of specific pathway targets during vertebrate axial development.
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Affiliation(s)
- Hiroki Hikasa
- Division of Cancer Genetics, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
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20
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Cavodeassi F, Houart C. Brain regionalization: Of signaling centers and boundaries. Dev Neurobiol 2012; 72:218-33. [DOI: 10.1002/dneu.20938] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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21
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Lin J, Wang X, Dorsky RI. Progenitor expansion in apc mutants is mediated by Jak/Stat signaling. BMC DEVELOPMENTAL BIOLOGY 2011; 11:73. [PMID: 22136118 PMCID: PMC3247185 DOI: 10.1186/1471-213x-11-73] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 12/02/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND Mutations in APC, a negative regulator of the Wnt/ß-catenin pathway, can cause cancer as well as profound developmental defects. In both cases, affected cells adopt a proliferative progenitor state and fail to differentiate. While the upregulation of some target genes of Wnt/ß-catenin signaling has been shown to mediate these phenotypes in individual tissues, it is unclear whether a common mechanism underlies the defects in APC mutants. RESULTS Here we show that stat3, a known oncogene and a target of ß-catenin in multiple tissues, is upregulated in apc mutant zebrafish embryos. We further demonstrate that Jak/Stat signaling is necessary for the increased level of proliferation and neural progenitor gene expression observed in apc mutants. CONCLUSIONS Together, our data suggest that the regulation of Jak/Stat signaling may represent a conserved mechanism explaining the expansion of undifferentiated cells downstream of APC mutations.
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Affiliation(s)
- Junji Lin
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
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22
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Kim S, Chung AY, Kim D, Kim YS, Kim HS, Kwon HW, Huh TL, Park HC. Tcf3 function is required for the inhibition of oligodendroglial fate specification in the spinal cord of zebrafish embryos. Mol Cells 2011; 32:383-8. [PMID: 21904879 PMCID: PMC3887649 DOI: 10.1007/s10059-011-0152-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 08/11/2011] [Accepted: 08/12/2011] [Indexed: 12/20/2022] Open
Abstract
The generation of various subtypes of neurons and glial cells at the right time and place is crucial for the proper development of the vertebrate CNS. Although the mechanisms and factors for the regulation of neuronal diversity in the CNS have been well studied, the mechanisms regulating the sequential production of neuronal and glial cells from neural precursors remain poorly understood. This study shows that Tcf3, a member of the Lef/Tcf family of proteins, is required to inhibit the premature oligodendroglial fate specification of spinal cord precursors using the transgenic zebrafish, which expresses a dominant repressor form of Tcf3 under the control of a heat-shock inducible promoter. In addition, the data revealed that Tcf3 function in oligodendroglial fate specification is mediated independently of canonical Wnt signaling. Altogether, these results show a novel function for Tcf3 in regulating the timing of oligodendroglial fate specification in the spinal cord.
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Affiliation(s)
| | | | | | - Young-Seop Kim
- Department of Genetic Engineering, Kyungpook National University, Daegu 702-701, Korea
| | - Hyung-Seok Kim
- Department of Genetic Engineering, Kyungpook National University, Daegu 702-701, Korea
| | - Hyung-Wook Kwon
- World Class University Biomodulation Major, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea
| | - Tae-Lin Huh
- Department of Genetic Engineering, Kyungpook National University, Daegu 702-701, Korea
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Repressor transcription factor 7-like 1 promotes adipogenic competency in precursor cells. Proc Natl Acad Sci U S A 2011; 108:16271-6. [PMID: 21914845 DOI: 10.1073/pnas.1109409108] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The identification of factors that define adipocyte precursor potential has important implications for obesity. Preadipocytes are fibroblastoid cells committed to becoming round lipid-laden adipocytes. In vitro, this differentiation process is facilitated by confluency, followed by adipogenic stimuli. During adipogenesis, a large number of cytostructural genes are repressed before adipocyte gene induction. Here we report that the transcriptional repressor transcription factor 7-like 1 (TCF7L1) binds and directly regulates the expression of cell structure genes. Depletion of TCF7L1 inhibits differentiation, because TCF7L1 indirectly induces the adipogenic transcription factor peroxisome proliferator-activated receptor γ in a manner that can be replaced by inhibition of myosin II activity. TCF7L1 is induced by cell contact in adipogenic cell lines, and ectopic expression of TCF7L1 alleviates the confluency requirement for adipocytic differentiation of precursor cells. In contrast, TCF7L1 is not induced during confluency of non-adipogenic fibroblasts, and, remarkably, forced expression of TCF7L1 is sufficient to commit non-adipogenic fibroblasts to an adipogenic fate. These results establish TCF7L1 as a transcriptional hub coordinating cell-cell contact with the transcriptional repression required for adipogenic competency.
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Abstract
Wnt signaling pathways control lineage specification in vertebrate embryos and regulate pluripotency in embryonic stem (ES) cells, but how the balance between progenitor self-renewal and differentiation is achieved during axis specification and tissue patterning remains highly controversial. The context- and stage-specific effects of the different Wnt pathways produce complex and sometimes opposite outcomes that help to generate embryonic cell diversity. Although the results of recent studies of the Wnt/β-catenin pathway in ES cells appear to be surprising and controversial, they converge on the same conserved mechanism that leads to the inactivation of TCF3-mediated repression.
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Affiliation(s)
- Sergei Y Sokol
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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25
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Kim HS, Dorsky RI. Tcf7l1 is required for spinal cord progenitor maintenance. Dev Dyn 2011; 240:2256-64. [PMID: 21932308 DOI: 10.1002/dvdy.22716] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2011] [Indexed: 01/02/2023] Open
Abstract
Neural progenitor cells must be maintained during development in order to produce the full complement of neuronal and glial derivatives. While molecular pathways have been identified that inhibit progenitor differentiation, it is unclear whether the progenitor state itself is actively maintained. In this study, we have investigated the role of Tcf7l1 (formerly named Tcf3) in maintaining spinal progenitor characteristics and allowing the continued production of neurons and glia following primary neurogenesis. We find that spinal cord progenitor markers are progressively lost in embryos lacking Tcf7l1, and that the number of proliferative progenitors decreases accordingly. Furthermore, we show that the production of both neuronal and glial secondary derivatives of the pMN progenitor pool requires Tcf7l1. Together, these results indicate that Tcf7l1 plays an important role in spinal cord progenitor maintenance, indicating that this core function is conserved throughout multiple epithelial cell populations.
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Affiliation(s)
- Hyung-Seok Kim
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, USA
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26
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Wang H, Lei Q, Oosterveen T, Ericson J, Matise MP. Tcf/Lef repressors differentially regulate Shh-Gli target gene activation thresholds to generate progenitor patterning in the developing CNS. Development 2011; 138:3711-21. [PMID: 21775418 DOI: 10.1242/dev.068270] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During neural tube development, Shh signaling through Gli transcription factors is necessary to establish five distinct ventral progenitor domains that give rise to unique classes of neurons and glia that arise in specific positions along the dorsoventral axis. These cells are generated from progenitors that display distinct transcription factor gene expression profiles in specific domains in the ventricular zone. However, the molecular genetic mechanisms that control the differential spatiotemporal transcriptional responses of progenitor target genes to graded Shh-Gli signaling remain unclear. The current study demonstrates a role for Tcf/Lef repressor activity in this process. We show that Tcf3 and Tcf7L2 (Tcf4) are required for proper ventral patterning and function by independently regulating two Shh-Gli target genes, Nkx2.2 and Olig2, which are initially induced in a common pool of progenitors that ultimately segregate into unique territories giving rise to distinct progeny. Genetic and functional studies in vivo show that Tcf transcriptional repressors selectively elevate the strength and duration of Gli activity necessary to induce Nkx2.2, but have no effect on Olig2, and thereby contribute to the establishment of their distinct expression domains in cooperation with graded Shh signaling. Together, our data reveal a Shh-Gli-independent transcriptional input that is required to shape the precise spatial and temporal response to extracellular morphogen signaling information during lineage segregation in the CNS.
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Affiliation(s)
- Hui Wang
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA
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27
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Modulation of Tcf3 repressor complex composition regulates cdx4 expression in zebrafish. EMBO J 2011; 30:2894-907. [PMID: 21666599 DOI: 10.1038/emboj.2011.184] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 05/18/2011] [Indexed: 01/31/2023] Open
Abstract
The caudal homeobox (cdx) gene family is critical for specification of caudal body formation and erythropoiesis. In zebrafish, cdx4 expression is controlled by the Wnt pathway, but the molecular mechanism of this regulation is not fully understood. Here, we provide evidence that Tcf3 suppresses cdx4 expression through direct binding to multiple sites in the cdx4 gene regulatory region. Tcf3 requires corepressor molecules such as Groucho (Gro)/TLE and HDAC1 for activity. Using zebrafish embryos and cultured mammalian cells, we show that the transcription factor E4f1 derepresses cdx4 by dissociating corepressor proteins from Tcf3 without inhibiting its binding to cis-regulatory sites in the DNA. Further, the E3 ubiquitin ligase Lnx2b, acting as a scaffold protein irrespective of its enzymatic activity, counteracts the effects of E4f1. We propose that the modulation of Tcf3 repressor function by E4f1 assures precise and robust regulation of cdx4 expression in the caudal domain of the embryo.
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28
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Ulloa F, Martí E. Wnt won the war: antagonistic role of Wnt over Shh controls dorso-ventral patterning of the vertebrate neural tube. Dev Dyn 2010; 239:69-76. [PMID: 19681160 DOI: 10.1002/dvdy.22058] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The spinal cord has been used as a model to dissect the mechanisms that govern the patterning of tissues during animal development, since the principles that rule the dorso-ventral patterning of the neural tube are applicable to other systems. Signals that determine the dorso-ventral axis of the spinal cord include Sonic hedgehog (Shh), acting as a bona fide morphogenetic signal to determine ventral progenitor identities, and members of the Bmp and the Wnt families, acting in the dorsal neural tube. Although Wnts have been initially recognized as important in proliferation of neural progenitor cells, their role in the dorso-ventral patterning has been controversial. In this review, we discuss recent reports that show an important contribution of the Wnt canonical pathway in dorso-ventral pattern formation. These data allow building a model by which the ventralizing activity of Shh is antagonized by Wnt activity through the expression of Gli3, a potent inhibitor of the Shh pathway. Therefore, antagonistic interactions between canonical Wnt, promoting dorsal identities, and Shh pathways, inducing ventral ones, would define the dorso-ventral patterning of the developing central nervous system.
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Affiliation(s)
- Fausto Ulloa
- Institute for Research in Biomedicine, Parc Cientific de Barcelona; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Department of Cell Biology, University of Barcelona, Barcelona, Spain
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