1
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Pereira A, Diwakar J, Masserdotti G, Beşkardeş S, Simon T, So Y, Martín-Loarte L, Bergemann F, Vasan L, Schauer T, Danese A, Bocchi R, Colomé-Tatché M, Schuurmans C, Philpott A, Straub T, Bonev B, Götz M. Direct neuronal reprogramming of mouse astrocytes is associated with multiscale epigenome remodeling and requires Yy1. Nat Neurosci 2024; 27:1260-1273. [PMID: 38956165 PMCID: PMC11239498 DOI: 10.1038/s41593-024-01677-5] [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: 09/16/2022] [Accepted: 05/10/2024] [Indexed: 07/04/2024]
Abstract
Direct neuronal reprogramming is a promising approach to regenerate neurons from local glial cells. However, mechanisms of epigenome remodeling and co-factors facilitating this process are unclear. In this study, we combined single-cell multiomics with genome-wide profiling of three-dimensional nuclear architecture and DNA methylation in mouse astrocyte-to-neuron reprogramming mediated by Neurogenin2 (Ngn2) and its phosphorylation-resistant form (PmutNgn2), respectively. We show that Ngn2 drives multilayered chromatin remodeling at dynamic enhancer-gene interaction sites. PmutNgn2 leads to higher reprogramming efficiency and enhances epigenetic remodeling associated with neuronal maturation. However, the differences in binding sites or downstream gene activation cannot fully explain this effect. Instead, we identified Yy1, a transcriptional co-factor recruited by direct interaction with Ngn2 to its target sites. Upon deletion of Yy1, activation of neuronal enhancers, genes and ultimately reprogramming are impaired without affecting Ngn2 binding. Thus, our work highlights the key role of interactors of proneural factors in direct neuronal reprogramming.
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Affiliation(s)
- Allwyn Pereira
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
- Nantes Université, CHU Nantes, INSERM, TaRGeT - Translational Research in Gene Therapy, UMR 1089, Nantes, France
| | - Jeisimhan Diwakar
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Helmholtz Pioneer Campus, Helmholtz Center Munich, Neuherberg, Germany
| | - Giacomo Masserdotti
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
| | - Sude Beşkardeş
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Helmholtz Pioneer Campus, Helmholtz Center Munich, Neuherberg, Germany
| | - Tatiana Simon
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
| | - Younju So
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
| | - Lucía Martín-Loarte
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
| | - Franziska Bergemann
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
| | - Lakshmy Vasan
- Biological Science Platform, Sunnybrook Research Institute; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Tamas Schauer
- Biomedical Center Munich (BMC), Bioinformatic Core Facility, Faculty of Medicine, LMU Munich, Planegg, Germany
- Institute of Stem Cells and Epigenetics, Helmholtz Center Munich, Neuherberg, Germany
| | - Anna Danese
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
| | - Riccardo Bocchi
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany
- Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Maria Colomé-Tatché
- Institute of Computational Biology, Helmholtz Center Munich, Neuherberg, Germany
- Biomedical Center Munich (BMC), Physiological Chemistry, Faculty of Medicine, LMU Munich, Planegg, Germany
| | - Carol Schuurmans
- Biological Science Platform, Sunnybrook Research Institute; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Anna Philpott
- Wellcome-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Tobias Straub
- Biological Science Platform, Sunnybrook Research Institute; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Boyan Bonev
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany.
- Helmholtz Pioneer Campus, Helmholtz Center Munich, Neuherberg, Germany.
| | - Magdalena Götz
- Biomedical Center Munich (BMC), Physiological Genomics, LMU Munich, Planegg, Germany.
- Institute of Stem Cell Research, Helmholtz Center Munich, BMC LMU Munich, Planegg, Germany.
- Excellence Cluster of Systems Neurology (SYNERGY), Munich, Germany.
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2
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Péron S, Miyakoshi LM, Brill MS, Manzano-Franco D, Serrano-López J, Fan W, Marichal N, Ghanem A, Conzelmann KK, Karow M, Ortega F, Gascón S, Berninger B. Programming of neural progenitors of the adult subependymal zone towards a glutamatergic neuron lineage by neurogenin 2. Stem Cell Reports 2023; 18:2418-2433. [PMID: 37995703 PMCID: PMC10724369 DOI: 10.1016/j.stemcr.2023.10.019] [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: 08/21/2021] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/25/2023] Open
Abstract
Although adult subependymal zone (SEZ) neural stem cells mostly generate GABAergic interneurons, a small progenitor population expresses the proneural gene Neurog2 and produces glutamatergic neurons. Here, we determined whether Neurog2 could respecify SEZ neural stem cells and their progeny toward a glutamatergic fate. Retrovirus-mediated expression of Neurog2 induced the glutamatergic lineage markers TBR2 and TBR1 in cultured SEZ progenitors, which differentiated into functional glutamatergic neurons. Likewise, Neurog2-transduced SEZ progenitors acquired glutamatergic neuron hallmarks in vivo. Intriguingly, they failed to migrate toward the olfactory bulb and instead differentiated within the SEZ or the adjacent striatum, where they received connections from local neurons, as indicated by rabies virus-mediated monosynaptic tracing. In contrast, lentivirus-mediated expression of Neurog2 failed to reprogram early SEZ neurons, which maintained GABAergic identity and migrated to the olfactory bulb. Our data show that NEUROG2 can program SEZ progenitors toward a glutamatergic identity but fails to reprogram their neuronal progeny.
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Affiliation(s)
- Sophie Péron
- Research Group "Adult Neurogenesis and Cellular Reprogramming", Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Leo M Miyakoshi
- Physiological Genomics, Institute of Physiology, Ludwig-Maximilians University Munich, Munich, Germany
| | - Monika S Brill
- Institute of Neuronal Cell Biology, Technical University Munich, Munich, Germany; Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Diana Manzano-Franco
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute - CSIC, Madrid, Spain
| | - Julia Serrano-López
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Universidad Complutense de Madrid (UCM), Madrid, Spain; Instituto Universitario de Investigación en Neuroquímica (IUIN), Madrid, Spain; Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Wenqiang Fan
- Research Group "Adult Neurogenesis and Cellular Reprogramming", Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany
| | - Nicolás Marichal
- Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Alexander Ghanem
- Max von Pettenkofer Institute and Gene Center, Ludwig Maximilians-University Munich, Munich, Germany
| | - Karl-Klaus Conzelmann
- Max von Pettenkofer Institute and Gene Center, Ludwig Maximilians-University Munich, Munich, Germany
| | - Marisa Karow
- Institute of Biochemistry, Friedrich-Alexander Universität Nürnberg-Erlangen, Erlangen, Germany
| | - Felipe Ortega
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Universidad Complutense de Madrid (UCM), Madrid, Spain; Instituto Universitario de Investigación en Neuroquímica (IUIN), Madrid, Spain; Instituto de Investigación Sanitaria San Carlos (IdISSC), Madrid, Spain
| | - Sergio Gascón
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute - CSIC, Madrid, Spain.
| | - Benedikt Berninger
- Research Group "Adult Neurogenesis and Cellular Reprogramming", Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg University, Mainz, Germany; Centre for Developmental Neurobiology, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK; Focus Program Translational Neurosciences, Johannes Gutenberg University, Mainz, Germany.
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3
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Abstract
Cochlear hair cells (HCs) in the inner ear are responsible for sound detection. For HC fate specification, the master transcription factor Atoh1 is both necessary and sufficient. Atoh1 expression is dynamic and tightly regulated during development, but the cis-regulatory elements mediating this regulation remain unresolved. Unexpectedly, we found that deleting the only recognized Atoh1 enhancer, defined here as Eh1, failed to impair HC development. By using the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq), we discovered two additional Atoh1 enhancers: Eh2 and Eh3. Notably, Eh2 deletion was sufficient for impairing HC development, and concurrent deletion of Eh1 and Eh2 or all three enhancers resulted in nearly complete absence of HCs. Lastly, we showed that Atoh1 binds to all three enhancers, consistent with its autoregulatory function. Our findings reveal that the cooperative action of three distinct enhancers underpins effective Atoh1 regulation during HC development, indicating potential therapeutic approaches for HC regeneration.
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4
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Benavidez JM, Kim JH, Greenwald I. Influences of HLH-2 stability on anchor cell fate specification during Caenorhabditis elegans gonadogenesis. G3 GENES|GENOMES|GENETICS 2022; 12:6520806. [PMID: 35134193 PMCID: PMC8982380 DOI: 10.1093/g3journal/jkac028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/24/2022] [Indexed: 11/25/2022]
Abstract
The Caenorhabditis elegans E protein ortholog HLH-2 is required for the specification and function of the anchor cell, a unique, terminally differentiated somatic gonad cell that organizes uterine and vulval development. Initially, 4 cells—2 α cells and their sisters, the β cells—have the potential to be the sole anchor cell. The β cells rapidly lose anchor cell potential and invariably become ventral uterine precursor cells, while the 2 α cells interact via LIN-12/Notch to resolve which will be the anchor cell and which will become another ventral uterine precursor cell. HLH-2 protein stability is dynamically regulated in cells with anchor cell potential; initially present in all 4 cells, HLH-2 is degraded in presumptive ventral uterine precursor cells while remaining stable in the anchor cell. Here, we demonstrate that stability of HLH-2 protein is regulated by the activity of lin-12/Notch in both α and β cells. Our analysis provides evidence that activation of LIN-12 promotes degradation of HLH-2 as part of a negative feedback loop during the anchor cell/ventral uterine precursor cell decision by the α cells, and that absence of lin-12 activity in β cells increases HLH-2 stability and may account for their propensity to adopt the anchor cell fate in a lin-12 null background. We also performed an RNA interference screen of 232 ubiquitin-related genes and identified 7 genes that contribute to HLH-2 degradation in ventral uterine precursor cells; however, stabilizing HLH-2 by depleting ubiquitin ligases in a lin-12(+) background does not result in supernumerary anchor cells, suggesting that LIN-12 activation does not oppose hlh-2 activity solely by causing HLH-2 protein degradation. Finally, we provide evidence for lin-12-independent transcriptional regulation of hlh-2 in β cells that correlates with known differences in POP-1/TCF levels and anchor cell potential between α and β cells. Together, our results indicate that hlh-2 activity is regulated at multiple levels to restrict the anchor cell fate to a single cell.
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Affiliation(s)
- Justin M Benavidez
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Jee Hun Kim
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Iva Greenwald
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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5
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Soares DS, Homem CC, Castro DS. Function of Proneural Genes Ascl1 and Asense in Neurogenesis: How Similar Are They? Front Cell Dev Biol 2022; 10:838431. [PMID: 35252201 PMCID: PMC8894194 DOI: 10.3389/fcell.2022.838431] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/24/2022] [Indexed: 12/31/2022] Open
Abstract
Proneural genes were initially identified in Drosophila, where pioneer work on these important regulators of neural development was performed, and from which the term proneural function was coined. Subsequently, their counterparts in vertebrates were identified, and their function in neural development extensively characterized. The function of proneural transcription factors in flies and vertebrates is, however, very distinct. In flies, proneural genes play an early role in neural induction, by endowing neural competence to ectodermal cells. In contrast, vertebrate proneural genes are expressed only after neural specification, in neural stem and progenitor cells, where they play key regulatory functions in quiescence, proliferation, and neuronal differentiation. An exception to this scenario is the Drosophila proneural gene asense, which has a late onset of expression in neural stem cells of the developing embryo and larvae, similar to its vertebrate counterparts. Although the role of Asense remains poorly investigated, its expression pattern is suggestive of functions more in line with those of vertebrate proneural genes. Here, we revise our current understanding of the multiple activities of Asense and of its closest vertebrate homologue Ascl1 in neural stem/progenitor cell biology, and discuss possible parallels between the two transcription factors in neurogenesis regulation.
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Affiliation(s)
- Diogo S. Soares
- i3S Instituto de Investigação e Inovação em Saúde, IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Catarina C.F. Homem
- CEDOC, Nova Medical School, Faculdade de Ciências Médicas da Universidade Nova de Lisboa, Lisboa, Portugal
- *Correspondence: Catarina C.F. Homem, ; Diogo S. Castro,
| | - Diogo S. Castro
- i3S Instituto de Investigação e Inovação em Saúde, IBMC Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- *Correspondence: Catarina C.F. Homem, ; Diogo S. Castro,
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6
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Mechanisms of Binding Specificity among bHLH Transcription Factors. Int J Mol Sci 2021; 22:ijms22179150. [PMID: 34502060 PMCID: PMC8431614 DOI: 10.3390/ijms22179150] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 08/14/2021] [Accepted: 08/18/2021] [Indexed: 12/25/2022] Open
Abstract
The transcriptome of every cell is orchestrated by the complex network of interaction between transcription factors (TFs) and their binding sites on DNA. Disruption of this network can result in many forms of organism malfunction but also can be the substrate of positive natural selection. However, understanding the specific determinants of each of these individual TF-DNA interactions is a challenging task as it requires integrating the multiple possible mechanisms by which a given TF ends up interacting with a specific genomic region. These mechanisms include DNA motif preferences, which can be determined by nucleotide sequence but also by DNA’s shape; post-translational modifications of the TF, such as phosphorylation; and dimerization partners and co-factors, which can mediate multiple forms of direct or indirect cooperative binding. Binding can also be affected by epigenetic modifications of putative target regions, including DNA methylation and nucleosome occupancy. In this review, we describe how all these mechanisms have a role and crosstalk in one specific family of TFs, the basic helix-loop-helix (bHLH), with a very conserved DNA binding domain and a similar DNA preferred motif, the E-box. Here, we compile and discuss a rich catalog of strategies used by bHLH to acquire TF-specific genome-wide landscapes of binding sites.
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7
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Johnson RI. Hexagonal patterning of the Drosophila eye. Dev Biol 2021; 478:173-182. [PMID: 34245727 DOI: 10.1016/j.ydbio.2021.07.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 07/04/2021] [Accepted: 07/06/2021] [Indexed: 10/24/2022]
Abstract
A complex network of transcription factor interactions propagates across the larval eye disc to establish columns of evenly-spaced R8 precursor cells, the founding cells of Drosophila ommatidia. After the recruitment of additional photoreceptors to each ommatidium, the surrounding cells are organized into their stereotypical pattern during pupal development. These support cells - comprised of pigment and cone cells - are patterned to encapsulate the photoreceptors and separate ommatidia with an hexagonal honeycomb lattice. Since the proteins and processes essential for correct eye patterning are conserved, elucidating how these function and change during Drosophila eye patterning can substantially advance our understanding of transcription factor and signaling networks, cytoskeletal structures, adhesion complexes, and the biophysical properties of complex tissues during their morphogenesis. Our understanding of many of these aspects of Drosophila eye patterning is largely descriptive. Many important questions, especially relating to the regulation and integration of cellular events, remain.
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Affiliation(s)
- Ruth I Johnson
- Biology Department, Wesleyan University, 52 Lawn Avenue, Middletown, CT, USA.
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8
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Zhang T, Liu T, Mora N, Guegan J, Bertrand M, Contreras X, Hansen AH, Streicher C, Anderle M, Danda N, Tiberi L, Hippenmeyer S, Hassan BA. Generation of excitatory and inhibitory neurons from common progenitors via Notch signaling in the cerebellum. Cell Rep 2021; 35:109208. [PMID: 34107249 DOI: 10.1016/j.celrep.2021.109208] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 03/29/2021] [Accepted: 05/11/2021] [Indexed: 12/17/2022] Open
Abstract
Brain neurons arise from relatively few progenitors generating an enormous diversity of neuronal types. Nonetheless, a cardinal feature of mammalian brain neurogenesis is thought to be that excitatory and inhibitory neurons derive from separate, spatially segregated progenitors. Whether bi-potential progenitors with an intrinsic capacity to generate both lineages exist and how such a fate decision may be regulated are unknown. Using cerebellar development as a model, we discover that individual progenitors can give rise to both inhibitory and excitatory lineages. Gradations of Notch activity determine the fates of the progenitors and their daughters. Daughters with the highest levels of Notch activity retain the progenitor fate, while intermediate levels of Notch activity generate inhibitory neurons, and daughters with very low levels of Notch signaling adopt the excitatory fate. Therefore, Notch-mediated binary cell fate choice is a mechanism for regulating the ratio of excitatory to inhibitory neurons from common progenitors.
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Affiliation(s)
- Tingting Zhang
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France; Doctoral School of Biomedical Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Tengyuan Liu
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France; Doctoral School of Biomedical Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Natalia Mora
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France
| | - Justine Guegan
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France
| | - Mathilde Bertrand
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France
| | - Ximena Contreras
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Andi H Hansen
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Carmen Streicher
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Marica Anderle
- Armenise-Harvard Laboratory of Brain Disorders and Cancer, CIBIO, University of Trento, Via Sommarive 9, 38123 Trento, Italy
| | - Natasha Danda
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France
| | - Luca Tiberi
- Armenise-Harvard Laboratory of Brain Disorders and Cancer, CIBIO, University of Trento, Via Sommarive 9, 38123 Trento, Italy
| | - Simon Hippenmeyer
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Bassem A Hassan
- Institut du Cerveau (ICM), Sorbonne Université, INSERM, CNRS, Hôpital Pitié-Salpêtrière, Paris, France.
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9
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Iyer AA, Groves AK. Transcription Factor Reprogramming in the Inner Ear: Turning on Cell Fate Switches to Regenerate Sensory Hair Cells. Front Cell Neurosci 2021; 15:660748. [PMID: 33854418 PMCID: PMC8039129 DOI: 10.3389/fncel.2021.660748] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/08/2021] [Indexed: 12/15/2022] Open
Abstract
Non-mammalian vertebrates can restore their auditory and vestibular hair cells naturally by triggering the regeneration of adjacent supporting cells. The transcription factor ATOH1 is a key regulator of hair cell development and regeneration in the inner ear. Following the death of hair cells, supporting cells upregulate ATOH1 and give rise to new hair cells. However, in the mature mammalian cochlea, such natural regeneration of hair cells is largely absent. Transcription factor reprogramming has been used in many tissues to convert one cell type into another, with the long-term hope of achieving tissue regeneration. Reprogramming transcription factors work by altering the transcriptomic and epigenetic landscapes in a target cell, resulting in a fate change to the desired cell type. Several studies have shown that ATOH1 is capable of reprogramming cochlear non-sensory tissue into cells resembling hair cells in young animals. However, the reprogramming ability of ATOH1 is lost with age, implying that the potency of individual hair cell-specific transcription factors may be reduced or lost over time by mechanisms that are still not clear. To circumvent this, combinations of key hair cell transcription factors have been used to promote hair cell regeneration in older animals. In this review, we summarize recent findings that have identified and studied these reprogramming factor combinations for hair cell regeneration. Finally, we discuss the important questions that emerge from these findings, particularly the feasibility of therapeutic strategies using reprogramming factors to restore human hearing in the future.
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Affiliation(s)
- Amrita A. Iyer
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
| | - Andrew K. Groves
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
- Program in Genetics & Genomics, Houston, TX, United States
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, United States
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10
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Oproescu AM, Han S, Schuurmans C. New Insights Into the Intricacies of Proneural Gene Regulation in the Embryonic and Adult Cerebral Cortex. Front Mol Neurosci 2021; 14:642016. [PMID: 33658912 PMCID: PMC7917194 DOI: 10.3389/fnmol.2021.642016] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 01/26/2021] [Indexed: 12/21/2022] Open
Abstract
Historically, the mammalian brain was thought to lack stem cells as no new neurons were found to be made in adulthood. That dogma changed ∼25 years ago with the identification of neural stem cells (NSCs) in the adult rodent forebrain. However, unlike rapidly self-renewing mature tissues (e.g., blood, intestinal crypts, skin), the majority of adult NSCs are quiescent, and those that become 'activated' are restricted to a few neurogenic zones that repopulate specific brain regions. Conversely, embryonic NSCs are actively proliferating and neurogenic. Investigations into the molecular control of the quiescence-to-proliferation-to-differentiation continuum in the embryonic and adult brain have identified proneural genes encoding basic-helix-loop-helix (bHLH) transcription factors (TFs) as critical regulators. These bHLH TFs initiate genetic programs that remove NSCs from quiescence and drive daughter neural progenitor cells (NPCs) to differentiate into specific neural cell subtypes, thereby contributing to the enormous cellular diversity of the adult brain. However, new insights have revealed that proneural gene activities are context-dependent and tightly regulated. Here we review how proneural bHLH TFs are regulated, with a focus on the murine cerebral cortex, drawing parallels where appropriate to other organisms and neural tissues. We discuss upstream regulatory events, post-translational modifications (phosphorylation, ubiquitinylation), protein-protein interactions, epigenetic and metabolic mechanisms that govern bHLH TF expression, stability, localization, and consequent transactivation of downstream target genes. These tight regulatory controls help to explain paradoxical findings of changes to bHLH activity in different cellular contexts.
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Affiliation(s)
- Ana-Maria Oproescu
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
| | - Sisu Han
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, Biological Sciences Platform, Toronto, ON, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
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11
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Fu Y, Yuan SS, Zhang LJ, Ji ZL, Quan XJ. Atonal bHLH transcription factor 1 is an important factor for maintaining the balance of cell proliferation and differentiation in tumorigenesis. Oncol Lett 2020; 20:2595-2605. [PMID: 32782577 PMCID: PMC7400680 DOI: 10.3892/ol.2020.11833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 09/06/2019] [Indexed: 12/15/2022] Open
Abstract
Establishing the link between cellular processes and oncogenesis may aid the elucidation of targeted and effective therapies against tumor cell proliferation and metastasis. Previous studies have investigated the mechanisms involved in maintaining the balance between cell proliferation, differentiation and migration. There is increased interest in determining the conditions that allow cancer stem cells to differentiate as well as the identification of molecules that may serve as novel drug targets. Furthermore, the study of various genes, including transcription factors, which serve a crucial role in cellular processes, may present a promising direction for future therapy. The present review described the role of the transcription factor atonal bHLH transcription factor 1 (ATOH1) in signaling pathways in tumorigenesis, particularly in cerebellar tumor medulloblastoma and colorectal cancer, where ATOH1 serves as an oncogene or tumor suppressor, respectively. Additionally, the present review summarized the associated therapeutic interventions for these two types of tumors and discussed novel clinical targets and approaches.
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Affiliation(s)
- Ying Fu
- Key Laboratory of Diabetes Prevention and Research, Endocrinology Center, Lu He Hospital, Capital Medical University, Beijing 101149, P.R. China
| | - Sha-Sha Yuan
- Key Laboratory of Diabetes Prevention and Research, Endocrinology Center, Lu He Hospital, Capital Medical University, Beijing 101149, P.R. China
| | - Li-Jie Zhang
- Key Laboratory of Diabetes Prevention and Research, Endocrinology Center, Lu He Hospital, Capital Medical University, Beijing 101149, P.R. China
| | - Zhi-Li Ji
- Key Laboratory of Diabetes Prevention and Research, Endocrinology Center, Lu He Hospital, Capital Medical University, Beijing 101149, P.R. China
| | - Xiao-Jiang Quan
- Key Laboratory of Diabetes Prevention and Research, Endocrinology Center, Lu He Hospital, Capital Medical University, Beijing 101149, P.R. China.,Laboratory of Brain Development, Institut du Cerveau et de la Moelle Épinière, Hôpital Pitié-Salpêtrière, 75013 Paris, France
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12
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Shan Y, Zhang Y, Zhao Y, Wang T, Zhang J, Yao J, Ma N, Liang Z, Huang W, Huang K, Zhang T, Su Z, Chen Q, Zhu Y, Wu C, Zhou T, Sun W, Wei Y, Zhang C, Li C, Su S, Liao B, Zhong M, Zhong X, Nie J, Pei D, Pan G. JMJD3 and UTX determine fidelity and lineage specification of human neural progenitor cells. Nat Commun 2020; 11:382. [PMID: 31959746 PMCID: PMC6971254 DOI: 10.1038/s41467-019-14028-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 12/13/2019] [Indexed: 02/08/2023] Open
Abstract
Neurogenesis, a highly orchestrated process, entails the transition from a pluripotent to neural state and involves neural progenitor cells (NPCs) and neuronal/glial subtypes. However, the precise epigenetic mechanisms underlying fate decision remain poorly understood. Here, we delete KDM6s (JMJD3 and/or UTX), the H3K27me3 demethylases, in human embryonic stem cells (hESCs) and show that their deletion does not impede NPC generation from hESCs. However, KDM6-deficient NPCs exhibit poor proliferation and a failure to differentiate into neurons and glia. Mechanistically, both JMJD3 and UTX are found to be enriched in gene loci essential for neural development in hNPCs, and KDM6 impairment leads to H3K27me3 accumulation and blockade of DNA accessibility at these genes. Interestingly, forced expression of neuron-specific chromatin remodelling BAF (nBAF) rescues the neuron/glia defect in KDM6-deficient NPCs despite H3K27me3 accumulation. Our findings uncover the differential requirement of KDM6s in specifying NPCs and neurons/glia and highlight the contribution of individual epigenetic regulators in fate decisions in a human development model. Neurogenesis is an ordered transition from pluriptotent cells to neural precursor cells (NPCs) to neurons. Here the authors show that loss of the lysine demethylases JMJD3 and UTX leads reduced DNA accessibility at neurogenesis loci in human NPCs, and that the chromatin remodeller BAF can rescue differentiation defects.
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Affiliation(s)
- Yongli Shan
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Yanqi Zhang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Yuan Zhao
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Tianyu Wang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Jingyuan Zhang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Jiao Yao
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Ning Ma
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China
| | - Zechuan Liang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Wenhao Huang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Ke Huang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Tian Zhang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Zhenghui Su
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Qianyu Chen
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Yanling Zhu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Chuman Wu
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Tiancheng Zhou
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Wei Sun
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Yanxing Wei
- Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Cong Zhang
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Chenxu Li
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Shuquan Su
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Baojian Liao
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Mei Zhong
- Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Xiaofen Zhong
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Jinfu Nie
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Duanqing Pei
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China.,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China
| | - Guangjin Pan
- CAS Key Laboratory of Regenerative Biology, Joint School of Life Sciences, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou Medical University, Guangzhou, 510530, China. .,Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China. .,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China. .,Shandong Medicinal Biotechnology Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250012, China. .,Centre for Regenerative Medicine and Health, Hong Kong Institute of Science and Innovation, Chinese Academy of Sciences, Hong Kong, China.
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13
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Abstract
In utero electroporation is a rapid and powerful technique to study the development of many brain regions. This approach presents several advantages over other methods to study specific steps of brain development in vivo, from proliferation to synaptic integration. Here, we describe in detail the individual steps necessary to carry out the technique. We also highlight the variations that can be implemented to target different cerebral structures and to study specific steps of development.
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14
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Ramaekers A, Claeys A, Kapun M, Mouchel-Vielh E, Potier D, Weinberger S, Grillenzoni N, Dardalhon-Cuménal D, Yan J, Wolf R, Flatt T, Buchner E, Hassan BA. Altering the Temporal Regulation of One Transcription Factor Drives Evolutionary Trade-Offs between Head Sensory Organs. Dev Cell 2019; 50:780-792.e7. [PMID: 31447264 DOI: 10.1016/j.devcel.2019.07.027] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 04/24/2019] [Accepted: 07/25/2019] [Indexed: 12/30/2022]
Abstract
Size trade-offs of visual versus olfactory organs is a pervasive feature of animal evolution. This could result from genetic or functional constraints. We demonstrate that head sensory organ size trade-offs in Drosophila are genetically encoded and arise through differential subdivision of the head primordium into visual versus non-visual fields. We discover that changes in the temporal regulation of the highly conserved eyeless/Pax6 gene expression during development is a conserved mechanism for sensory trade-offs within and between Drosophila species. We identify a natural single nucleotide polymorphism in the cis-regulatory region of eyeless in a binding site of its repressor Cut that is sufficient to alter its temporal regulation and eye size. Because eyeless/Pax6 is a conserved regulator of head sensory placode subdivision, we propose that its temporal regulation is key to define the relative size of head sensory organs.
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Affiliation(s)
- Ariane Ramaekers
- Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Université, Inserm, CNRS, Paris, France.
| | - Annelies Claeys
- VIB Center for Brain and Disease, VIB, Leuven, Belgium; Center for Human Genetics, University of Leuven School of Medicine, Leuven, Belgium
| | - Martin Kapun
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Emmanuèle Mouchel-Vielh
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement, Institut de Biologie Paris Seine, LBD-IBPS), Paris, France
| | - Delphine Potier
- Aix-Marseille Université, CNRS, INSERM, CIML, Marseille, France
| | - Simon Weinberger
- VIB Center for Brain and Disease, VIB, Leuven, Belgium; Center for Human Genetics, University of Leuven School of Medicine, Leuven, Belgium
| | - Nicola Grillenzoni
- Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Université, Inserm, CNRS, Paris, France
| | - Delphine Dardalhon-Cuménal
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement, Institut de Biologie Paris Seine, LBD-IBPS), Paris, France
| | - Jiekun Yan
- VIB Center for Brain and Disease, VIB, Leuven, Belgium; Center for Human Genetics, University of Leuven School of Medicine, Leuven, Belgium
| | - Reinhard Wolf
- Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Erich Buchner
- Institute for Clinical Neurobiology, University Hospital Würzburg, Würzburg, Germany
| | - Bassem A Hassan
- Institut du Cerveau et de la Moelle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Sorbonne Université, Inserm, CNRS, Paris, France.
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15
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Zhang X, McGrath PS, Salomone J, Rahal M, McCauley HA, Schweitzer J, Kovall R, Gebelein B, Wells JM. A Comprehensive Structure-Function Study of Neurogenin3 Disease-Causing Alleles during Human Pancreas and Intestinal Organoid Development. Dev Cell 2019; 50:367-380.e7. [PMID: 31178402 DOI: 10.1016/j.devcel.2019.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 02/25/2019] [Accepted: 05/06/2019] [Indexed: 01/09/2023]
Abstract
Neurogenin3 (NEUROG3) is required for endocrine lineage formation of the pancreas and intestine. Patients with NEUROG3 mutations are born with congenital malabsorptive diarrhea due to complete loss of enteroendocrine cells, whereas endocrine pancreas development varies in an allele-specific manner. These findings suggest a context-dependent requirement for NEUROG3 in pancreas versus intestine. We utilized human tissue differentiated from NEUROG3-/- pluripotent stem cells for functional analyses. Most disease-associated alleles had hypomorphic or null phenotype in both tissues, whereas the S171fsX68 mutation had reduced activity in the pancreas but largely null in the intestine. Biochemical studies revealed NEUROG3 variants have distinct molecular defects with altered protein stability, DNA binding, and gene transcription. Moreover, NEUROG3 was highly unstable in the intestinal epithelium, explaining the enhanced sensitivity of intestinal defects relative to the pancreas. These studies emphasize that studies of human mutations in the endogenous tissue context may be required to assess structure-function relationships.
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Affiliation(s)
- Xinghao Zhang
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Patrick S McGrath
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Joseph Salomone
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Mohamed Rahal
- Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Heather A McCauley
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Jamie Schweitzer
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Rhett Kovall
- Department of Molecular Genetics, Biochemistry, & Microbiology, University of Cincinnati, Cincinnati, OH 45229, USA
| | - Brian Gebelein
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - James M Wells
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Center for Stem Cell and Organoid Medicine (CuSTOM), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Division of Endocrinology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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16
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Aydin B, Kakumanu A, Rossillo M, Moreno-Estellés M, Garipler G, Ringstad N, Flames N, Mahony S, Mazzoni EO. Proneural factors Ascl1 and Neurog2 contribute to neuronal subtype identities by establishing distinct chromatin landscapes. Nat Neurosci 2019; 22:897-908. [PMID: 31086315 PMCID: PMC6556771 DOI: 10.1038/s41593-019-0399-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 03/28/2019] [Indexed: 11/29/2022]
Abstract
Developmental programs that generate the astonishing neuronal diversity of the nervous system are not completely understood and thus present a significant challenge for clinical applications of guided cell differentiation strategies. Using direct neuronal programming of embryonic stem cells, we found that two main vertebrate proneural factors, Ascl1 and Neurog2, induce different neuronal fates by binding to largely different sets of genomic sites. Their divergent binding patterns are not determined by the previous chromatin state but are distinguished by enrichment of specific E-box sequences which reflect the binding preferences of the DNA-binding domains. The divergent Ascl1 and Neurog2 binding patterns result in distinct chromatin accessibility and enhancer activity profiles that differentially shape the binding of downstream transcription factors during neuronal differentiation. This study provides a mechanistic understanding of how transcription factors constrain terminal cell fates, and it delineates the importance of choosing the right proneural factor in neuronal reprogramming strategies.
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Affiliation(s)
- Begüm Aydin
- Department of Biology, New York University, New York, NY, USA.,Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA
| | - Akshay Kakumanu
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Mary Rossillo
- Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY, USA
| | - Mireia Moreno-Estellés
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Görkem Garipler
- Department of Biology, New York University, New York, NY, USA.,Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA
| | - Niels Ringstad
- Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY, USA
| | - Nuria Flames
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
| | - Esteban O Mazzoni
- Department of Biology, New York University, New York, NY, USA. .,Neuroscience Institute, Department of Neuroscience and Physiology, NYU School of Medicine, New York, NY, USA.
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17
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García-Morales D, Navarro T, Iannini A, Pereira PS, Míguez DG, Casares F. Dynamic Hh signalling can generate temporal information during tissue patterning. Development 2019; 146:dev.176933. [PMID: 30918051 DOI: 10.1242/dev.176933] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 03/19/2019] [Indexed: 12/28/2022]
Abstract
The differentiation of tissues and organs requires that cells exchange information in space and time. Spatial information is often conveyed by morphogens: molecules that disperse across receiving cells to generate signalling gradients. Cells translate such concentration gradients into space-dependent patterns of gene expression and cellular behaviour. But could morphogen gradients also convey developmental time? Here, by investigating the developmental role of Hh on a component of the Drosophila visual system, the ocellar retina, we have discovered that ocellar cells use the non-linear gradient of Hh as a temporal cue, collectively performing the biological equivalent of a mathematical logarithmic transformation. In this way, a morphogen diffusing from a non-moving source is decoded as a wave of differentiating photoreceptors that travels at constant speed throughout the retinal epithelium.
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Affiliation(s)
- Diana García-Morales
- CABD (CSIC-Universidad Pablo de Olavide-Junta de Andalucía), GEM-DMC2 Unit, Campus UPO, 41013 Seville, Spain
| | - Tomás Navarro
- CABD (CSIC-Universidad Pablo de Olavide-Junta de Andalucía), GEM-DMC2 Unit, Campus UPO, 41013 Seville, Spain
| | - Antonella Iannini
- CABD (CSIC-Universidad Pablo de Olavide-Junta de Andalucía), GEM-DMC2 Unit, Campus UPO, 41013 Seville, Spain
| | - Paulo S Pereira
- Instituto de Biologia Molecular e Celular/i3S, Universidade do Porto, 4200-135 Porto, Portugal
| | - David G Míguez
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Campus de Cantoblanco, 28049 Madrid, Spain
| | - Fernando Casares
- CABD (CSIC-Universidad Pablo de Olavide-Junta de Andalucía), GEM-DMC2 Unit, Campus UPO, 41013 Seville, Spain
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18
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Abstract
In this review from Murre, the evolution of HLH genes, the structures of HLH domains, and the elaborate activities of HLH proteins in multicellular life are discussed. Helix–loop–helix (HLH) proteins are dimeric transcription factors that control lineage- and developmental-specific gene programs. Genes encoding for HLH proteins arose in unicellular organisms >600 million years ago and then duplicated and diversified from ancestral genes across the metazoan and plant kingdoms to establish multicellularity. Hundreds of HLH proteins have been identified with diverse functions in a wide variety of cell types. HLH proteins orchestrate lineage specification, commitment, self-renewal, proliferation, differentiation, and homing. HLH proteins also regulate circadian clocks, protect against hypoxic stress, promote antigen receptor locus assembly, and program transdifferentiation. HLH proteins deposit or erase epigenetic marks, activate noncoding transcription, and sequester chromatin remodelers across the chromatin landscape to dictate enhancer–promoter communication and somatic recombination. Here the evolution of HLH genes, the structures of HLH domains, and the elaborate activities of HLH proteins in multicellular life are discussed.
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Affiliation(s)
- Cornelis Murre
- Division of Biological Sciences, University of California at San Diego, La Jolla, California 92903, USA
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19
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Mattiske T, Tan MH, Dearsley O, Cloosterman D, Hii CS, Gécz J, Shoubridge C. Regulating transcriptional activity by phosphorylation: A new mechanism for the ARX homeodomain transcription factor. PLoS One 2018; 13:e0206914. [PMID: 30419043 PMCID: PMC6231642 DOI: 10.1371/journal.pone.0206914] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 10/22/2018] [Indexed: 01/08/2023] Open
Abstract
Aristaless-related homeobox (ARX) gene encodes a paired-type homeodomain transcription factor with critical roles in development. Here we identify that ARX protein is phosphorylated. Using mass spectrometry and in vitro kinase assays we identify phosphorylation at serines 37, 67 and 174. Through yeast-2-hybrid and CoIP we identified PICK1 (Protein interacting with C kinase 1) binding with the C-terminal region of ARX. PICK1 is a scaffold protein known to facilitate phosphorylation of protein partners by protein kinase C alpha (PRKCA). We confirm that ARX is phosphorylated by PRKCA and demonstrate phosphorylation at serine 174. We demonstrate that phosphorylation is required for correct transcriptional activity of the ARX protein using transcriptome-wide analysis of gene expression of phospho-null mutants (alanines replacing serines) compared to ARX wild-type (ARX-WT) overexpressed in pancreatic alpha TC cells. Compared to untransfected cells, ARX-WT overexpression significantly altered expression of 70 genes (Log2FC >+/-1.0, P-value <0.05). There were fewer genes with significantly altered expression compared to untransfected cells with the double phospho-null mutant Ser37Ala+Ser67Ala (26%) and Ser174Ala (39%), respectively. We demonstrate that the c-terminal region of ARX required to bind PICK1 causes a shift in PICK1 subcellular localisation to the nucleus to co-locate with the ARX protein, and truncation of this C-terminal region leads to the same loss of transcriptional activation as S174A mutant. In conclusion, we show that ARX is phosphorylated at several sites and that this modification affects its transcriptional activity.
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Affiliation(s)
- Tessa Mattiske
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | - May H. Tan
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
| | - Oliver Dearsley
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
| | | | - Charles S. Hii
- Department of Immunopathology, SA-Pathology, Adelaide, Australia
| | - Jozef Gécz
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- Healthy Mothers and Babies, South Australian Health and Medical Research Institute, Adelaide, Australia
| | - Cheryl Shoubridge
- Adelaide Medical School, University of Adelaide, Adelaide, Australia
- Robinson Research Institute, University of Adelaide, Adelaide, Australia
- * E-mail:
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20
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Hardwick LJ, Philpott A. Interaction between opposing modes of phospho-regulation of the proneural proteins Ascl1 and Ngn2. Wellcome Open Res 2018; 3:129. [PMID: 30430141 PMCID: PMC6206610 DOI: 10.12688/wellcomeopenres.14848.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2018] [Indexed: 12/17/2022] Open
Abstract
From the relatively simple nervous system of Drosophila to the elaborate mammalian cortex, neurogenesis requires exceptional spatial and temporal precision to co-ordinate progenitor cell proliferation and subsequent differentiation to a diverse range of neurons and glia. A limited number of transiently expressed proneural basic-helix-loop-helix (bHLH) transcription factors, for example achaete-scute-complex (as-c) and atonal (ato) in Drosophila and the vertebrate homologues Ascl1 and Neurogenin2 (Ngn2), are able to orchestrate the onset of neuronal determination, context-dependent subtype selection and even influence later aspects of neuronal migration and maturation. Within the last decade, two models have emerged to explain how the temporal activity of proneural determination factors is regulated by phosphorylation at distinct sites. One model describes how cell-cycle associated phosphorylation on multiple sites in the N and C termini of vertebrate proneural proteins limits neuronal differentiation in cycling progenitor cells. A second model describes phosphorylation on a single site in the bHLH domain of Drosophila atonal that acts as a binary switch, where phosphorylation terminates proneural activity. Here we combine activating mutations of phosphorylation sites in the N- and C- termini with an inhibitory phospho-mimetic mutation in the bHLH domain of Ascl1 and Ngn2 proteins, and test their functions in vivo using Xenopus embryos to determine which mode of phospho-regulation dominates. Enhancing activity by preventing N- and C terminal phosphorylation cannot overcome the inhibitory effect of mimicking phosphorylation of the bHLH domain. Thus we have established a hierarchy between these two modes of proneural protein control and suggest a model of temporal regulation for proneural protein activity.
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Affiliation(s)
- Laura J.A. Hardwick
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 1QR, UK
- Department of Oncology, University of Cambridge, Cambridge, CB2 0XZ, UK
- Peterhouse, University of Cambridge, Cambridge, CB2 1RD, UK
| | - Anna Philpott
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 1QR, UK
- Department of Oncology, University of Cambridge, Cambridge, CB2 0XZ, UK
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21
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Cell cycle-dependent phosphorylation and regulation of cellular differentiation. Biochem Soc Trans 2018; 46:1083-1091. [PMID: 30242121 DOI: 10.1042/bst20180276] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/02/2018] [Accepted: 08/03/2018] [Indexed: 02/07/2023]
Abstract
Embryogenesis requires an exquisite regulation of cell proliferation, cell cycle withdrawal and differentiation into a massively diverse range of cells at the correct time and place. Stem cells also remain to varying extents in different adult tissues, acting in tissue homeostasis and repair. Therefore, regulated proliferation and subsequent differentiation of stem and progenitor cells remains pivotal throughout life. Recent advances have characterised the cell cycle dynamics, epigenetics, transcriptome and proteome accompanying the transition from proliferation to differentiation, revealing multiple bidirectional interactions between the cell cycle machinery and factors driving differentiation. Here, we focus on a direct mechanistic link involving phosphorylation of differentiation-associated transcription factors by cell cycle-associated Cyclin-dependent kinases. We discuss examples from the three embryonic germ layers to illustrate this regulatory mechanism that co-ordinates the balance between cell proliferation and differentiation.
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22
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Le Dréau G, Escalona R, Fueyo R, Herrera A, Martínez JD, Usieto S, Menendez A, Pons S, Martinez-Balbas MA, Marti E. E proteins sharpen neurogenesis by modulating proneural bHLH transcription factors' activity in an E-box-dependent manner. eLife 2018; 7:37267. [PMID: 30095408 PMCID: PMC6126921 DOI: 10.7554/elife.37267] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 08/09/2018] [Indexed: 12/18/2022] Open
Abstract
Class II HLH proteins heterodimerize with class I HLH/E proteins to regulate transcription. Here, we show that E proteins sharpen neurogenesis by adjusting the neurogenic strength of the distinct proneural proteins. We find that inhibiting BMP signaling or its target ID2 in the chick embryo spinal cord, impairs the neuronal production from progenitors expressing ATOH1/ASCL1, but less severely that from progenitors expressing NEUROG1/2/PTF1a. We show this context-dependent response to result from the differential modulation of proneural proteins’ activity by E proteins. E proteins synergize with proneural proteins when acting on CAGSTG motifs, thereby facilitating the activity of ASCL1/ATOH1 which preferentially bind to such motifs. Conversely, E proteins restrict the neurogenic strength of NEUROG1/2 by directly inhibiting their preferential binding to CADATG motifs. Since we find this mechanism to be conserved in corticogenesis, we propose this differential co-operation of E proteins with proneural proteins as a novel though general feature of their mechanism of action. The brain and spinal cord are made up of a range of cell types that carry out different roles within the central nervous system. Each type of neuron is uniquely specialized to do its job. Neurons are produced early during development, when they differentiate from a group of cells called neural progenitor cells. Within these groups, molecules called proneural proteins control which types of neurons will develop from the neural progenitor cells, and how many of them. Proneural proteins work by binding to specific patterns in the DNA, called E-boxes, with the help of E proteins. E proteins are typically understood to be passive partners, working with each different proneural protein indiscriminately. However, Le Dréau, Escalona et al. discovered that E proteins in fact have a much more active role to play. Using chick embryos, it was found that E proteins influence the way different proneural proteins bind to DNA. The E proteins have preferences for certain E-boxes in the DNA, just like proneural proteins do. The E proteins enhanced the activity of the proneural proteins that share their E-box preference, and reined in the activity of proneural proteins that prefer other E-boxes. As a result, the E proteins controlled the ability of these proteins to instruct neural progenitor cells to produce specific, specialized neurons, and thus ensured that the distinct types of neurons were produced in appropriate amounts. These findings will help shed light on the roles E proteins play in the development of the central nervous system, and the processes that control growth and lead to cell diversity. The results may also have applications in the field of regenerative medicine, as proneural proteins play an important role in cell reprogramming.
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Affiliation(s)
- Gwenvael Le Dréau
- Department of Developmental Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - René Escalona
- Department of Developmental Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Raquel Fueyo
- Department of Molecular Genomics, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Antonio Herrera
- Department of Developmental Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Juan D Martínez
- Department of Developmental Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Susana Usieto
- Department of Developmental Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Anghara Menendez
- Department of Cell Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Sebastian Pons
- Department of Cell Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Marian A Martinez-Balbas
- Department of Molecular Genomics, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
| | - Elisa Marti
- Department of Developmental Biology, Instituto de Biología Molecular de Barcelona, Barcelona, Spain
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23
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Li T, Bellen HJ, Groves AK. Using Drosophila to study mechanisms of hereditary hearing loss. Dis Model Mech 2018; 11:11/6/dmm031492. [PMID: 29853544 PMCID: PMC6031363 DOI: 10.1242/dmm.031492] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Johnston's organ - the hearing organ of Drosophila - has a very different structure and morphology to that of the hearing organs of vertebrates. Nevertheless, it is becoming clear that vertebrate and invertebrate auditory organs share many physiological, molecular and genetic similarities. Here, we compare the molecular and cellular features of hearing organs in Drosophila with those of vertebrates, and discuss recent evidence concerning the functional conservation of Usher proteins between flies and mammals. Mutations in Usher genes cause Usher syndrome, the leading cause of human deafness and blindness. In Drosophila, some Usher syndrome proteins appear to physically interact in protein complexes that are similar to those described in mammals. This functional conservation highlights a rational role for Drosophila as a model for studying hearing, and for investigating the evolution of auditory organs, with the aim of advancing our understanding of the genes that regulate human hearing and the pathogenic mechanisms that lead to deafness.
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Affiliation(s)
- Tongchao Li
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Andrew K Groves
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA .,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
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24
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Baker NE, Brown NL. All in the family: proneural bHLH genes and neuronal diversity. Development 2018; 145:145/9/dev159426. [PMID: 29720483 DOI: 10.1242/dev.159426] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Proneural basic Helix-Loop-Helix (bHLH) proteins are required for neuronal determination and the differentiation of most neural precursor cells. These transcription factors are expressed in vastly divergent organisms, ranging from sponges to primates. Here, we review proneural bHLH gene evolution and function in the Drosophila and vertebrate nervous systems, arguing that the Drosophila gene atonal provides a useful platform for understanding proneural gene structure and regulation. We also discuss how functional equivalency experiments using distinct proneural genes can reveal how proneural gene duplication and divergence are interwoven with neuronal complexity.
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Affiliation(s)
- Nicholas E Baker
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461 USA
| | - Nadean L Brown
- Department of Cell Biology and Human Anatomy, University of California, One Shields Avenue, Davis, CA 95616 USA
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25
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Mora N, Oliva C, Fiers M, Ejsmont R, Soldano A, Zhang TT, Yan J, Claeys A, De Geest N, Hassan BA. A Temporal Transcriptional Switch Governs Stem Cell Division, Neuronal Numbers, and Maintenance of Differentiation. Dev Cell 2018; 45:53-66.e5. [DOI: 10.1016/j.devcel.2018.02.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 02/12/2018] [Accepted: 02/26/2018] [Indexed: 01/06/2023]
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26
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Lloret-Fernández C, Maicas M, Mora-Martínez C, Artacho A, Jimeno-Martín Á, Chirivella L, Weinberg P, Flames N. A transcription factor collective defines the HSN serotonergic neuron regulatory landscape. eLife 2018; 7:32785. [PMID: 29553368 PMCID: PMC5916565 DOI: 10.7554/elife.32785] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 03/16/2018] [Indexed: 01/02/2023] Open
Abstract
Cell differentiation is controlled by individual transcription factors (TFs) that together activate a selection of enhancers in specific cell types. How these combinations of TFs identify and activate their target sequences remains poorly understood. Here, we identify the cis-regulatory transcriptional code that controls the differentiation of serotonergic HSN neurons in Caenorhabditis elegans. Activation of the HSN transcriptome is directly orchestrated by a collective of six TFs. Binding site clusters for this TF collective form a regulatory signature that is sufficient for de novo identification of HSN neuron functional enhancers. Among C. elegans neurons, the HSN transcriptome most closely resembles that of mouse serotonergic neurons. Mouse orthologs of the HSN TF collective also regulate serotonergic differentiation and can functionally substitute for their worm counterparts which suggests deep homology. Our results identify rules governing the regulatory landscape of a critically important neuronal type in two species separated by over 700 million years.
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Affiliation(s)
- Carla Lloret-Fernández
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Miren Maicas
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Carlos Mora-Martínez
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Alejandro Artacho
- Departamento de Genómica y Salud, Centro Superior de Investigación en Salud Pública, FISABIO, Valencia, Spain
| | - Ángela Jimeno-Martín
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Laura Chirivella
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
| | - Peter Weinberg
- Department of Biological Sciences, Howard Hughes Medical Institute, Columbia University Medical Center, New York, United States
| | - Nuria Flames
- Developmental Neurobiology Unit, Instituto de Biomedicina de Valencia IBV-CSIC, Valencia, Spain
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27
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Subcellular localisation modulates ubiquitylation and degradation of Ascl1. Sci Rep 2018; 8:4625. [PMID: 29545540 PMCID: PMC5854709 DOI: 10.1038/s41598-018-23056-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Accepted: 03/01/2018] [Indexed: 12/31/2022] Open
Abstract
The proneural transcription factor Ascl1 is a master regulator of neurogenesis, coordinating proliferation and differentiation in the central nervous system. While its expression is well characterised, post-translational regulation is much less well understood. Here we demonstrate that a population of chromatin-bound Ascl1 can be found associated with short chains of ubiquitin while cytoplasmic Ascl1 harbours much longer ubiquitin chains. Only cytoplasmic ubiquitylation targets Ascl1 for destruction, which occurs by conjugation of ubiquitin to lysines in the basic helix-loop-helix domain of Ascl1 and requires the E3 ligase Huwe1. In contrast, chromatin-bound Ascl1 associated with short ubiquitin-chains, which can occur on lysines within the N-terminal region or the bHLH domain and is not mediated by Huwe1, is not targeted for ubiquitin-mediated destruction. We therefore offer further insights into post-translational regulation of Ascl1, highlighting complex regulation of ubiquitylation and degradation in the cytoplasm and on chromatin.
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28
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Dennis DJ, Han S, Schuurmans C. bHLH transcription factors in neural development, disease, and reprogramming. Brain Res 2018; 1705:48-65. [PMID: 29544733 DOI: 10.1016/j.brainres.2018.03.013] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 03/07/2018] [Accepted: 03/10/2018] [Indexed: 01/16/2023]
Abstract
The formation of functional neural circuits in the vertebrate central nervous system (CNS) requires that appropriate numbers of the correct types of neuronal and glial cells are generated in their proper places and times during development. In the embryonic CNS, multipotent progenitor cells first acquire regional identities, and then undergo precisely choreographed temporal identity transitions (i.e. time-dependent changes in their identity) that determine how many neuronal and glial cells of each type they will generate. Transcription factors of the basic-helix-loop-helix (bHLH) family have emerged as key determinants of neural cell fate specification and differentiation, ensuring that appropriate numbers of specific neuronal and glial cell types are produced. Recent studies have further revealed that the functions of these bHLH factors are strictly regulated. Given their essential developmental roles, it is not surprising that bHLH mutations and de-regulated expression are associated with various neurological diseases and cancers. Moreover, the powerful ability of bHLH factors to direct neuronal and glial cell fate specification and differentiation has been exploited in the relatively new field of cellular reprogramming, in which pluripotent stem cells or somatic stem cells are converted to neural lineages, often with a transcription factor-based lineage conversion strategy that includes one or more of the bHLH genes. These concepts are reviewed herein.
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Affiliation(s)
- Daniel J Dennis
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, ON M4N3M5, Canada
| | - Sisu Han
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, ON M4N3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Carol Schuurmans
- Sunnybrook Research Institute, 2075 Bayview Ave, Toronto, ON M4N3M5, Canada; Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
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29
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Adnani L, Han S, Li S, Mattar P, Schuurmans C. Mechanisms of Cortical Differentiation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 336:223-320. [DOI: 10.1016/bs.ircmb.2017.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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30
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Miesfeld JB, Glaser T, Brown NL. The dynamics of native Atoh7 protein expression during mouse retinal histogenesis, revealed with a new antibody. Gene Expr Patterns 2018; 27:114-121. [PMID: 29225067 PMCID: PMC5835195 DOI: 10.1016/j.gep.2017.11.006] [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: 10/12/2017] [Revised: 11/17/2017] [Accepted: 11/28/2017] [Indexed: 12/19/2022]
Abstract
The Atoh7 transcription factor catalyzes the rate-limiting step in the specification of retinal ganglion cells (RGCs). As a tool to study vertebrate retinal development, we validate an antibody that recognizes human and mouse Atoh7 polypeptide, using informative knockout and transgenic mouse tissues and overexpression experiments. The transient features of Atoh7 protein expression during retinal neurogenesis match the expected pattern at the tissue and cellular level. Further, we compare endogenous Atoh7 to established RGC markers, reporter mouse lines and cell cycle markers, demonstrating the utility of the antibody to investigate molecular mechanisms of retinal histogenesis.
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Affiliation(s)
- Joel B Miesfeld
- Department of Cell Biology & Human Anatomy, University of California, Davis School of Medicine, One Shields Avenue, Davis, CA 95616, United States
| | - Tom Glaser
- Department of Cell Biology & Human Anatomy, University of California, Davis School of Medicine, One Shields Avenue, Davis, CA 95616, United States
| | - Nadean L Brown
- Department of Cell Biology & Human Anatomy, University of California, Davis School of Medicine, One Shields Avenue, Davis, CA 95616, United States.
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31
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Gálvez H, Tena JJ, Giraldez F, Abelló G. The Repression of Atoh1 by Neurogenin1 during Inner Ear Development. Front Mol Neurosci 2017; 10:321. [PMID: 29104531 PMCID: PMC5655970 DOI: 10.3389/fnmol.2017.00321] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/21/2017] [Indexed: 01/01/2023] Open
Abstract
Atonal homolog 1 (Atoh1) and Neurogenin1 (Neurog1) are basic Helix-Loop-Helix (bHLH) transcription factors crucial for the generation of hair cells (HCs) and neurons in the inner ear. Both genes are induced early in development, but the expression of Atoh1 is counteracted by Neurog1. As a result, HC development is prevented during neurogenesis. This work aimed at understanding the molecular basis of this interaction. Atoh1 regulation depends on a 3'Atoh1-enhancer that is the site for Atoh1 autoregulation. Reporter assays on chick embryos and P19 cells show that Neurog1 hampers the autoactivation of Atoh1, the effect being cell autonomous and independent on Notch activity. Assay for Transposase-Accessible Chromatin with high throughput sequencing (ATAC-Seq) analysis shows that the region B of the 3'Atoh1-enhancer is accessible during development and sufficient for both activation and repression. Neurog1 requires the regions flanking the class A E-box to show its repressor effect, however, it does not require binding to DNA for Atoh1 repression. This depends on the dimerization domains Helix-1 and Helix-2 and the reduction of Atoh1 protein levels. The results point towards the acceleration of Atoh1 mRNA degradation as the potential mechanism for the reduction of Atoh1 levels. Such a mechanism dissociates the prevention of Atoh1 expression in neurosensory progenitors from the unfolding of the neurogenic program.
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Affiliation(s)
- Héctor Gálvez
- DCEXS, Universitat Pompeu Fabra (UPF) - Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
| | - Juan J Tena
- Centro Andaluz de Biología del Desarrollo, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | - Fernando Giraldez
- DCEXS, Universitat Pompeu Fabra (UPF) - Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
| | - Gina Abelló
- DCEXS, Universitat Pompeu Fabra (UPF) - Parc de Recerca Biomèdica de Barcelona (PRBB), Barcelona, Spain
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32
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Lin H, Zhu X, Chen G, Song L, Gao L, Khand AA, Chen Y, Lin G, Tao Q. KDM3A-mediated demethylation of histone H3 lysine 9 facilitates the chromatin binding of Neurog2 during neurogenesis. Development 2017; 144:3674-3685. [DOI: 10.1242/dev.144113] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 08/25/2017] [Indexed: 12/26/2022]
Abstract
Neurog2 is a crucial regulator of neuronal fate specification and differentiation in vivo and in vitro. However, it remains unclear how Neurog2 transactivates neuronal genes that are silenced by repressive chromatin. Here, we provide evidence that the histone H3 lysine 9 demethylase KDM3A facilitates the Xenopus Neurog2 (formerly known as Xngnr1) chromatin accessibility during neuronal transcription. Loss-of-function analyses reveal that KDM3A is not required for the transition of naive ectoderm to neural progenitor cells but is essential for primary neuron formation. ChIP series followed by qPCR analyses reveal that Neurog2 promotes the removal of the repressive H3K9me2 marks and addition of active histone marks, including H3K27ac and H3K4me3, at the NeuroD1 and Tubb2b promoters; this activity depends on the presence of KDM3A because Neurog2, via its C-terminal domain, interacts with KDM3A. Interestingly, KDM3A is dispensable for the neuronal transcription initiated by Ascl1, a proneural factor related to neurogenin in the bHLH family. In summary, our findings uncover a crucial role for histone H3K9 demethylation during Neurog2-mediated neuronal transcription and help in the understanding of the different activities of Neurog2 and Ascl1 in initiating neuronal development.
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Affiliation(s)
- Hao Lin
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
| | - Xuechen Zhu
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
| | - Geng Chen
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
| | - Lei Song
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
| | - Li Gao
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
| | - Aftab A. Khand
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
| | - Ying Chen
- Tongji University School of Life Sciences and Technology, Shanghai, China 200092
| | - Gufa Lin
- Tongji University School of Life Sciences and Technology, Shanghai, China 200092
| | - Qinghua Tao
- MOE Key Laboratory of Protein Sciences, Tsinghua University School of Life Sciences, Beijing, China 100084
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33
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The Potential of Targeting Brain Pathology with Ascl1/Mash1. Cells 2017; 6:cells6030026. [PMID: 28832532 PMCID: PMC5617972 DOI: 10.3390/cells6030026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 08/21/2017] [Accepted: 08/23/2017] [Indexed: 01/08/2023] Open
Abstract
The proneural factor Achaete-scute complex-like 1 (Ascl1/Mash1) acts as a pioneering transcription factor that initializes neuronal reprogramming. It drives neural progenitors and non-neuronal cells to exit the cell cycle, and promotes neuronal differentiation by activating neuronal target genes, even those that are normally repressed. Importantly, force-expression of Ascl1 was shown to drive proliferative reactive astroglia formed during stroke and glioblastoma stem cells towards neuronal differentiation, and this could potentially diminish CNS damage resulting from their proliferation. As a pro-neural factor, Ascl1 also has the general effect of enhancing neurite growth by damaged or surviving neurons. Here, a hypothesis that brain pathologies associated with traumatic/ischemic injury and malignancy could be targeted with pro-neural factors that drives neuronal differentiation is formulated and explored. Although a good number of caveats exist, exogenous over-expression of Ascl1, alone or in combination with other factors, may be worth further consideration as a therapeutic approach in brain injury and cancer.
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An Atoh1-S193A Phospho-Mutant Allele Causes Hearing Deficits and Motor Impairment. J Neurosci 2017; 37:8583-8594. [PMID: 28729444 DOI: 10.1523/jneurosci.0295-17.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/20/2017] [Accepted: 06/29/2017] [Indexed: 12/21/2022] Open
Abstract
Atonal homolog 1 (Atoh1) is a basic helix-loop-helix (bHLH) transcription factor that is essential for the genesis, survival, and maturation of a variety of neuronal and non-neuronal cell populations, including those involved in proprioception, interoception, balance, respiration, and hearing. Such diverse functions require fine regulation at the transcriptional and protein levels. Here, we show that serine 193 (S193) is phosphorylated in Atoh1's bHLH domain in vivo Knock-in mice of both sexes bearing a GFP-tagged phospho-dead S193A allele on a null background (Atoh1S193A/lacZ) exhibit mild cerebellar foliation defects, motor impairments, partial pontine nucleus migration defects, cochlear hair cell degeneration, and profound hearing loss. We also found that Atoh1 heterozygous mice of both sexes (Atoh1lacZ/+) have adult-onset deafness. These data indicate that different cell types have different degrees of vulnerability to loss of Atoh1 function and that hypomorphic Atoh1 alleles should be considered in human hearing loss.SIGNIFICANCE STATEMENT The discovery that Atonal homolog 1 (Atoh1) governs the development of the sensory hair cells in the inner ear led to therapeutic efforts to restore these cells in cases of human deafness. Because prior studies of Atoh1-heterozygous mice did not examine or report on hearing loss in mature animals, it has not been clinical practice to sequence ATOH1 in people with deafness. Here, in seeking to understand how phosphorylation of Atoh1 modulates its effects in vivo, we discovered that inner ear hair cells are much more vulnerable to loss of Atoh1 function than other Atoh1-positive cell types and that heterozygous mice actually develop hearing loss late in life. This opens up the possibility that missense mutations in ATOH1 could increase human vulnerability to loss of hair cells because of aging or trauma.
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Sallé J, Gervais L, Boumard B, Stefanutti M, Siudeja K, Bardin AJ. Intrinsic regulation of enteroendocrine fate by Numb. EMBO J 2017; 36:1928-1945. [PMID: 28533229 DOI: 10.15252/embj.201695622] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 12/25/2022] Open
Abstract
How terminal cell fates are specified in dynamically renewing adult tissues is not well understood. Here we explore terminal cell fate establishment during homeostasis using the enteroendocrine cells (EEs) of the adult Drosophila midgut as a paradigm. Our data argue against the existence of local feedback signals, and we identify Numb as an intrinsic regulator of EE fate. Our data further indicate that Numb, with alpha-adaptin, acts upstream or in parallel of known regulators of EE fate to limit Notch signaling, thereby facilitating EE fate acquisition. We find that Numb is regulated in part through its asymmetric and symmetric distribution during stem cell divisions; however, its de novo synthesis is also required during the differentiation of the EE cell. Thus, this work identifies Numb as a crucial factor for cell fate choice in the adult Drosophila intestine. Furthermore, our findings demonstrate that cell-intrinsic control mechanisms of terminal cell fate acquisition can result in a balanced tissue-wide production of terminally differentiated cell types.
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Affiliation(s)
- Jérémy Sallé
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Louis Gervais
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Benjamin Boumard
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France.,Département de Biologie, École Normale Supérieure de Lyon, Lyon, France
| | - Marine Stefanutti
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Katarzyna Siudeja
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Allison J Bardin
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France .,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
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36
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Costa A, Powell LM, Lowell S, Jarman AP. Atoh1 in sensory hair cell development: constraints and cofactors. Semin Cell Dev Biol 2017; 65:60-68. [DOI: 10.1016/j.semcdb.2016.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/26/2016] [Accepted: 10/13/2016] [Indexed: 11/28/2022]
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37
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Gálvez H, Abelló G, Giraldez F. Signaling and Transcription Factors during Inner Ear Development: The Generation of Hair Cells and Otic Neurons. Front Cell Dev Biol 2017; 5:21. [PMID: 28393066 PMCID: PMC5364141 DOI: 10.3389/fcell.2017.00021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 03/02/2017] [Indexed: 12/21/2022] Open
Abstract
Integration between cell signals and bHLH transcription factors plays a prominent role during the development of hair cells of the inner ear. Hair cells are the sensory receptors of the inner ear, responsible for the mechano-transduction of sound waves into electrical signals. They derive from multipotent progenitors that reside in the otic placode. Progenitor commitment is the result of cell signaling from the surrounding tissues that result in the restricted expression of SoxB1 transcription factors, Sox2 and Sox3. In turn, they induce the expression of Neurog1 and Atoh1, two bHLH factors that specify neuronal and hair cell fates, respectively. Neuronal and hair cell development, however, do not occur simultaneously. Hair cell development is prevented during neurogenesis and prosensory stages, resulting in the delay of hair cell development with respect to neuron production. Negative interactions between Neurog1 and Atoh1, and of Atoh1 with other bHLH factors driven by Notch signaling, like Hey1 and Hes5, account for this delay. In summary, the regulation of Atoh1 and hair cell development relies on interactions between cell signaling and bHLH transcription factors that dictate cell fate and timing decisions during development. Interestingly, these mechanisms operate as well during hair cell regeneration after damage and during stem cell directed differentiation, making developmental studies instrumental for improving therapies for hearing impairment.
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Affiliation(s)
- Héctor Gálvez
- Developmental Biology, CEXS, Parc de Recerca Biomèdica de Barcelona, Universitat Pompeu Fabra Barcelona, Spain
| | - Gina Abelló
- Developmental Biology, CEXS, Parc de Recerca Biomèdica de Barcelona, Universitat Pompeu Fabra Barcelona, Spain
| | - Fernando Giraldez
- Developmental Biology, CEXS, Parc de Recerca Biomèdica de Barcelona, Universitat Pompeu Fabra Barcelona, Spain
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38
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Guillemot F, Hassan BA. Beyond proneural: emerging functions and regulations of proneural proteins. Curr Opin Neurobiol 2016; 42:93-101. [PMID: 28025176 DOI: 10.1016/j.conb.2016.11.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 11/25/2016] [Accepted: 11/28/2016] [Indexed: 11/28/2022]
Abstract
Proneural proteins, which include Ascl1, Atoh1 and Neurogenins épinière in vertebrates and Achaete-Scute proteins and Atonal in Drosophila, are expressed in the developing nervous system throughout the animal kingdom and have an essential and well-characterised role in specifying the neural identity of progenitors. New properties and additional roles of these factors have emerged in recent years, including the regulation of stem cell proliferation and the capacity to reprogram many types of cells into neurons. This review will focus on these recent findings. The review will also discuss the mechanisms that allow proneural proteins to induce the transcription of their target genes in different chromatin contexts and the phosphorylation events and other post-transcriptional mechanisms that regulate the proneural proteins themselves.
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Affiliation(s)
| | - Bassem A Hassan
- Sorbonne Universités, UPMC Univ Paris 06, Inserm, CNRS, Institut du Cerveau et la Moëlle Epinière (ICM) - Hôpital Pitié-Salpêtrière, Boulevard de l'hôpital, F-75013 Paris, France.
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39
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An evolutionary conserved interaction between the Gcm transcription factor and the SF1 nuclear receptor in the female reproductive system. Sci Rep 2016; 6:37792. [PMID: 27886257 PMCID: PMC5122895 DOI: 10.1038/srep37792] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 11/01/2016] [Indexed: 01/08/2023] Open
Abstract
NR5A1 is essential for the development and for the function of steroid producing glands of the reproductive system. Moreover, its misregulation is associated with endometriosis, which is the first cause of infertility in women. Hr39, the Drosophila ortholog of NR5A1, is expressed and required in the secretory cells of the spermatheca, the female exocrine gland that ensures fertility by secreting substances that attract and capacitate the spermatozoids. We here identify a direct regulator of Hr39 in the spermatheca: the Gcm transcription factor. Furthermore, lack of Gcm prevents the production of the secretory cells and leads to female sterility in Drosophila. Hr39 regulation by Gcm seems conserved in mammals and involves the modification of the DNA methylation profile of mNr5a1. This study identifies a new molecular pathway in female reproductive system development and suggests a role for hGCM in the progression of reproductive tract diseases in humans.
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40
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Bandyopadhyay M, Bishop CP, Bidwai AP. The Conserved MAPK Site in E(spl)-M8, an Effector of Drosophila Notch Signaling, Controls Repressor Activity during Eye Development. PLoS One 2016; 11:e0159508. [PMID: 27428327 PMCID: PMC4948772 DOI: 10.1371/journal.pone.0159508] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/05/2016] [Indexed: 12/12/2022] Open
Abstract
The specification of patterned R8 photoreceptors at the onset of eye development depends on timely inhibition of Atonal (Ato) by the Enhancer of split (E(spl) repressors. Repression of Ato by E(spl)-M8 requires the kinase CK2 and is inhibited by the phosphatase PP2A. The region targeted by CK2 harbors additional conserved Ser residues, raising the prospect of regulation via multi-site phosphorylation. Here we investigate one such motif that meets the consensus for modification by MAPK, a well-known effector of Epidermal Growth Factor Receptor (EGFR) signaling. Our studies reveal an important role for the predicted MAPK site of M8 during R8 birth. Ala/Asp mutations reveal that the CK2 and MAPK sites ensure that M8 repression of Ato and the R8 fate occurs in a timely manner and at a specific stage (stage-2/3) of the morphogenetic furrow (MF). M8 repression of Ato is mitigated by halved EGFR dosage, and this effect requires an intact MAPK site. Accordingly, variants with a phosphomimetic Asp at the MAPK site exhibit earlier (inappropriate) activity against Ato even at stage-1 of the MF, where a positive feedback-loop is necessary to raise Ato levels to a threshold sufficient for the R8 fate. Analysis of deletion variants reveals that both kinase sites (CK2 and MAPK) contribute to ‘cis’-inhibition of M8. This key regulation by CK2 and MAPK is bypassed by the E(spl)D mutation encoding the truncated protein M8*, which potently inhibits Ato at stage-1 of R8 birth. We also provide evidence that PP2A likely targets the MAPK site. Thus multi-site phosphorylation controls timely onset of M8 repressor activity in the eye, a regulation that appears to be dispensable in the bristle. The high conservation of the CK2 and MAPK sites in the insect E(spl) proteins M7, M5 and Mγ, and their mammalian homologue HES6, suggest that this mode of regulation may enable E(spl)/HES proteins to orchestrate repression by distinct tissue-specific mechanisms, and is likely to have broader applicability than has been previously recognized.
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Affiliation(s)
- Mohna Bandyopadhyay
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Clifton P. Bishop
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
| | - Ashok P. Bidwai
- Department of Biology, West Virginia University, Morgantown, West Virginia, United States of America
- * E-mail:
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Abstract
Building a nervous system requires a precise sequence of genetic transitions, mediated in part by the temporal and spatial regulation of transcription factors. Quan et al. add to our understanding of this regulation by describing an evolutionarily conserved post-translational mechanism that rapidly extinguishes proneural protein activity in neural precursors.
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Affiliation(s)
- Richard S Mann
- Departments of Biochemistry and Molecular Biophysics and Systems Biology, Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.
| | - Clare E Howard
- Department of Biochemistry and Molecular Biophysics, Zuckerman Mind Brain Behavior Institute, Medical Scientist Training Program, Columbia University, New York, NY 10027, USA
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