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Bachu VS, Kandoi S, Park KU, Kaufman ML, Schwanke M, Lamba DA, Brzezinski JA. An enhancer located in a Pde6c intron drives transient expression in the cone photoreceptors of developing mouse and human retinas. Dev Biol 2022; 488:131-150. [PMID: 35644251 PMCID: PMC10676565 DOI: 10.1016/j.ydbio.2022.05.012] [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: 01/27/2022] [Revised: 04/29/2022] [Accepted: 05/19/2022] [Indexed: 02/04/2023]
Abstract
How cone photoreceptors are formed during retinal development is only partially known. This is in part because we do not fully understand the gene regulatory network responsible for cone genesis. We reasoned that cis-regulatory elements (enhancers) active in nascent cones would be regulated by the same upstream network that controls cone formation. To dissect this network, we searched for enhancers active in developing cones. By electroporating enhancer-driven fluorescent reporter plasmids, we observed that a sequence within an intron of the cone-specific Pde6c gene acted as an enhancer in developing mouse cones. Similar fluorescent reporter plasmids were used to generate stable transgenic human induced pluripotent stem cells that were then grown into three-dimensional human retinal organoids. These organoids contained fluorescently labeled cones, demonstrating that the Pde6c enhancer was also active in human cones. We observed that enhancer activity was transient and labeled a minor population of developing rod photoreceptors in both mouse and human systems. This cone-enriched pattern argues that the Pde6c enhancer is activated in cells poised between rod and cone fates. Additionally, it suggests that the Pde6c enhancer is activated by the same regulatory network that selects or stabilizes cone fate choice. To further understand this regulatory network, we identified essential enhancer sequence regions through a series of mutagenesis experiments. This suggested that the Pde6c enhancer was regulated by transcription factor binding at five or more locations. Binding site predictions implicated transcription factor families known to control photoreceptor formation and families not previously associated with cone development. These results provide a framework for deciphering the gene regulatory network that controls cone genesis in both human and mouse systems. Our new transgenic human stem cell lines provide a tool for determining which cone developmental mechanisms are shared and distinct between mice and humans.
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Affiliation(s)
- Vismaya S Bachu
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sangeetha Kandoi
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, USA
| | - Ko Uoon Park
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Michael L Kaufman
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Michael Schwanke
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Deepak A Lamba
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, University of California San Francisco, San Francisco, CA, USA
| | - Joseph A Brzezinski
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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2
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Young BK, Ramakrishnan C, Ganjawala T, Wang P, Deisseroth K, Tian N. An uncommon neuronal class conveys visual signals from rods and cones to retinal ganglion cells. Proc Natl Acad Sci U S A 2021; 118:e2104884118. [PMID: 34702737 PMCID: PMC8612366 DOI: 10.1073/pnas.2104884118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 01/01/2023] Open
Abstract
Neurons in the central nervous system (CNS) are distinguished by the neurotransmitter types they release, their synaptic connections, morphology, and genetic profiles. To fully understand how the CNS works, it is critical to identify all neuronal classes and reveal their synaptic connections. The retina has been extensively used to study neuronal development and circuit formation. Here, we describe a previously unidentified interneuron in mammalian retina. This interneuron shares some morphological, physiological, and molecular features with retinal bipolar cells, such as receiving input from photoreceptors and relaying visual signals to retinal ganglion cells. It also shares some features with amacrine cells (ACs), particularly Aii-ACs, such as their neurite morphology in the inner plexiform layer, the expression of some AC-specific markers, and possibly the release of the inhibitory neurotransmitter glycine. Thus, we unveil an uncommon interneuron, which may play an atypical role in vision.
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Affiliation(s)
- Brent K Young
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT 84132
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84114
| | | | - Tushar Ganjawala
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48202
| | - Ping Wang
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT 84132
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Ning Tian
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, UT 84132;
- Interdepartmental Neuroscience Program, University of Utah, Salt Lake City, UT 84114
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84132
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84132
- Veterans Affairs Medical Center, Salt Lake City, UT 84148
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3
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Retinal Lineage Therapeutic Specific Effect of Human Orbital and Abdominal Adipose-Derived Mesenchymal Stem Cells. Stem Cells Int 2021; 2021:7022247. [PMID: 34712333 PMCID: PMC8548122 DOI: 10.1155/2021/7022247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/09/2021] [Accepted: 09/02/2021] [Indexed: 12/14/2022] Open
Abstract
Retinal degenerative diseases are one of the main causes of complete blindness in aged population. In this study, we compared the therapeutic potential for retinal degeneration of human mesenchymal stem cells derived from abdominal subcutaneous fat (ABASCs) or from orbital fat (OASCs) due to their accessibility and mutual embryonic origin with retinal tissue, respectively. OASCs were found to protect RPE cells from cell death and were demonstrated to increase early RPE precursor markers, while ABASCs showed a raise in retinal precursor marker expression. Subretinal transplantation of OASCs in a mouse model of retinal degeneration led to restoration of the RPE layer while transplantation of ABASCs resulted in a significant restoration of the photoreceptor layer. Taken together, we demonstrated a lineage-specific therapeutic effect for either OASCs or ABASCs in retinal regeneration.
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Kaufman ML, Goodson NB, Park KU, Schwanke M, Office E, Schneider SR, Abraham J, Hensley A, Jones KL, Brzezinski JA. Initiation of Otx2 expression in the developing mouse retina requires a unique enhancer and either Ascl1 or Neurog2 activity. Development 2021; 148:dev199399. [PMID: 34143204 PMCID: PMC8254865 DOI: 10.1242/dev.199399] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 05/10/2021] [Indexed: 11/20/2022]
Abstract
During retinal development, a large subset of progenitors upregulates the transcription factor Otx2, which is required for photoreceptor and bipolar cell formation. How these retinal progenitor cells initially activate Otx2 expression is unclear. To address this, we investigated the cis-regulatory network that controls Otx2 expression in mice. We identified a minimal enhancer element, DHS-4D, that drove expression in newly formed OTX2+ cells. CRISPR/Cas9-mediated deletion of DHS-4D reduced OTX2 expression, but this effect was diminished in postnatal development. Systematic mutagenesis of the enhancer revealed that three basic helix-loop-helix (bHLH) transcription factor-binding sites were required for its activity. Single cell RNA-sequencing of nascent Otx2+ cells identified the bHLH factors Ascl1 and Neurog2 as candidate regulators. CRISPR/Cas9 targeting of these factors showed that only the simultaneous loss of Ascl1 and Neurog2 prevented OTX2 expression. Our findings suggest that Ascl1 and Neurog2 act either redundantly or in a compensatory fashion to activate the DHS-4D enhancer and Otx2 expression. We observed redundancy or compensation at both the transcriptional and enhancer utilization levels, suggesting that the mechanisms governing Otx2 regulation in the retina are flexible and robust.
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Affiliation(s)
- Michael L. Kaufman
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Noah B. Goodson
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ko Uoon Park
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Michael Schwanke
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Emma Office
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Sophia R. Schneider
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Joy Abraham
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Austin Hensley
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Kenneth L. Jones
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Joseph A. Brzezinski
- Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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5
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George SM, Lu F, Rao M, Leach LL, Gross JM. The retinal pigment epithelium: Development, injury responses, and regenerative potential in mammalian and non-mammalian systems. Prog Retin Eye Res 2021; 85:100969. [PMID: 33901682 DOI: 10.1016/j.preteyeres.2021.100969] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/23/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022]
Abstract
Diseases that result in retinal pigment epithelium (RPE) degeneration, such as age-related macular degeneration (AMD), are among the leading causes of blindness worldwide. Atrophic (dry) AMD is the most prevalent form of AMD and there are currently no effective therapies to prevent RPE cell death or restore RPE cells lost from AMD. An intriguing approach to treat AMD and other RPE degenerative diseases is to develop therapies focused on stimulating endogenous RPE regeneration. For this to become feasible, a deeper understanding of the mechanisms underlying RPE development, injury responses and regenerative potential is needed. In mammals, RPE regeneration is extremely limited; small lesions can be repaired by the expansion of adjacent RPE cells, but large lesions cannot be repaired as remaining RPE cells are unable to functionally replace lost RPE tissue. In some injury paradigms, RPE cells proliferate but do not regenerate a morphologically normal monolayer, while in others, proliferation is pathogenic and results in further disruption to the retina. This is in contrast to non-mammalian vertebrates, which possess tremendous RPE regenerative potential. Here, we discuss what is known about RPE formation during development in mammalian and non-mammalian vertebrates, we detail the processes by which RPE cells respond to injury, and we describe examples of RPE-to-retina and RPE-to-RPE regeneration in non-mammalian vertebrates. Finally, we outline barriers to RPE-dependent regeneration in mammals that could potentially be overcome to stimulate a regenerative response from the RPE.
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Affiliation(s)
- Stephanie M George
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Fangfang Lu
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA; Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, 410011, China
| | - Mishal Rao
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Lyndsay L Leach
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Jeffrey M Gross
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA; Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA.
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6
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Chan CSY, Lonfat N, Zhao R, Davis AE, Li L, Wu MR, Lin CH, Ji Z, Cepko CL, Wang S. Cell type- and stage-specific expression of Otx2 is regulated by multiple transcription factors and cis-regulatory modules in the retina. Development 2020; 147:dev.187922. [PMID: 32631829 DOI: 10.1242/dev.187922] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 06/22/2020] [Indexed: 12/22/2022]
Abstract
Transcription factors (TFs) are often used repeatedly during development and homeostasis to control distinct processes in the same and/or different cellular contexts. Considering the limited number of TFs in the genome and the tremendous number of events that need to be regulated, re-use of TFs is necessary. We analyzed how the expression of the homeobox TF, orthodenticle homeobox 2 (Otx2), is regulated in a cell type- and stage-specific manner during development in the mouse retina. We identified seven Otx2 cis-regulatory modules (CRMs), among which the O5, O7 and O9 CRMs mark three distinct cellular contexts of Otx2 expression. We discovered that Otx2, Crx and Sox2, which are well-known TFs regulating retinal development, bind to and activate the O5, O7 or O9 CRMs, respectively. The chromatin status of these three CRMs was found to be distinct in vivo in different retinal cell types and at different stages. We conclude that retinal cells use a cohort of TFs with different expression patterns and multiple CRMs with different chromatin configurations to regulate the expression of Otx2 precisely.
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Affiliation(s)
- Candace S Y Chan
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA 94304, USA
| | - Nicolas Lonfat
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Rong Zhao
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Alexander E Davis
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA 94304, USA
| | - Liang Li
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA 94304, USA.,Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, 410011, China
| | - Man-Ru Wu
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA 94304, USA
| | - Cheng-Hui Lin
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA 94304, USA
| | - Zhe Ji
- Department of Bioengineering, Northwestern University, Evanston, IL 60208, USA
| | - Constance L Cepko
- Departments of Genetics and Ophthalmology, Blavatnik Institute, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Sui Wang
- Department of Ophthalmology, Mary M. and Sash A. Spencer Center for Vision Research, Byers Eye Institute, Stanford University, Stanford, CA 94304, USA
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7
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Markitantova Y, Simirskii V. Inherited Eye Diseases with Retinal Manifestations through the Eyes of Homeobox Genes. Int J Mol Sci 2020; 21:E1602. [PMID: 32111086 PMCID: PMC7084737 DOI: 10.3390/ijms21051602] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/21/2020] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Retinal development is under the coordinated control of overlapping networks of signaling pathways and transcription factors. The paper was conceived as a review of the data and ideas that have been formed to date on homeobox genes mutations that lead to the disruption of eye organogenesis and result in inherited eye/retinal diseases. Many of these diseases are part of the same clinical spectrum and have high genetic heterogeneity with already identified associated genes. We summarize the known key regulators of eye development, with a focus on the homeobox genes associated with monogenic eye diseases showing retinal manifestations. Recent advances in the field of genetics and high-throughput next-generation sequencing technologies, including single-cell transcriptome analysis have allowed for deepening of knowledge of the genetic basis of inherited retinal diseases (IRDs), as well as improve their diagnostics. We highlight some promising avenues of research involving molecular-genetic and cell-technology approaches that can be effective for IRDs therapy. The most promising neuroprotective strategies are aimed at mobilizing the endogenous cellular reserve of the retina.
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8
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Clark BS, Stein-O'Brien GL, Shiau F, Cannon GH, Davis-Marcisak E, Sherman T, Santiago CP, Hoang TV, Rajaii F, James-Esposito RE, Gronostajski RM, Fertig EJ, Goff LA, Blackshaw S. Single-Cell RNA-Seq Analysis of Retinal Development Identifies NFI Factors as Regulating Mitotic Exit and Late-Born Cell Specification. Neuron 2019; 102:1111-1126.e5. [PMID: 31128945 PMCID: PMC6768831 DOI: 10.1016/j.neuron.2019.04.010] [Citation(s) in RCA: 255] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 02/07/2019] [Accepted: 04/03/2019] [Indexed: 12/26/2022]
Abstract
Precise temporal control of gene expression in neuronal progenitors is necessary for correct regulation of neurogenesis and cell fate specification. However, the cellular heterogeneity of the developing CNS has posed a major obstacle to identifying the gene regulatory networks that control these processes. To address this, we used single-cell RNA sequencing to profile ten developmental stages encompassing the full course of retinal neurogenesis. This allowed us to comprehensively characterize changes in gene expression that occur during initiation of neurogenesis, changes in developmental competence, and specification and differentiation of each major retinal cell type. We identify the NFI transcription factors (Nfia, Nfib, and Nfix) as selectively expressed in late retinal progenitor cells and show that they control bipolar interneuron and Müller glia cell fate specification and promote proliferative quiescence.
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Affiliation(s)
- Brian S Clark
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Genevieve L Stein-O'Brien
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Institute for Data Intensive Engineering and Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Fion Shiau
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gabrielle H Cannon
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Emily Davis-Marcisak
- Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thomas Sherman
- Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Clayton P Santiago
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thanh V Hoang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Fatemeh Rajaii
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rebecca E James-Esposito
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Richard M Gronostajski
- Department of Biochemistry, Genetics, Genomics and Bioinformatics Graduate Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Elana J Fertig
- Department of Oncology, Division of Biostatistics and Bioinformatics, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Institute for Data Intensive Engineering and Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Institute for Computational Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Mathematical Institute for Data Science, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Applied Mathematics and Statistics, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Loyal A Goff
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; McKusick-Nathans Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Center for Human Systems Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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9
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Tang X, Jiao L, Zheng M, Yan Y, Nie Q, Wu T, Wan X, Zhang G, Li Y, Wu S, Jiang B, Cai H, Xu P, Duan J, Lin X. Tau Deficiency Down-Regulated Transcription Factor Orthodenticle Homeobox 2 Expression in the Dopaminergic Neurons in Ventral Tegmental Area and Caused No Obvious Motor Deficits in Mice. Neuroscience 2018; 373:52-59. [PMID: 29337233 PMCID: PMC5819331 DOI: 10.1016/j.neuroscience.2018.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 12/22/2017] [Accepted: 01/03/2018] [Indexed: 12/24/2022]
Abstract
Tau protein participates in microtubule stabilization, axonal transport, and protein trafficking. Loss of normal tau function will exert a negative effect. However, current knowledge on the impact of tau deficiency on the motor behavior and related neurobiological changes is controversial. In this study, we examined motor functions and analyzed several proteins implicated in the maintenance of midbrain dopaminergic (DA) neurons (mDANs) function of adult and aged tau+/+, tau+/-, tau-/- mice. We found tau deficiency could not induce significant motor disorders. However, we discovered lower expression levels of transcription factors Orthodenticle homeobox 2 (OTX2) of mDANs in older aged mice. Compared with age-matched tau+/+ mice, there were 54.1% lower (p = 0.0192) OTX2 protein (OTX2-fluorescence intensity) in VTA DA neurons of tau+/- mice and 43.6% lower (p = 0.0249) OTX2 protein in VTA DA neurons of tau-/- mice at 18 months old. Combined with the relevant reports, our results suggested that tau deficiency alone might not be enough to mimic the pathology of Parkinson's disease. However, OTX2 down-regulation indicates that mDANs of tau-deficient mice will be more sensitive to toxic damage from MPTP.
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Affiliation(s)
- Xiaolu Tang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Luyan Jiao
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Meige Zheng
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Yan Yan
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Qi Nie
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Ting Wu
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Xiaomei Wan
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Guofeng Zhang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Yonglin Li
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Song Wu
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Bin Jiang
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China
| | - Huaibin Cai
- Transgenics Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangdong 510120, China.
| | - Jinhai Duan
- Department of Neurology & Guangdong Institute of Geriatrics, Guangdong General Hospital, #106, Zhongshan 2nd Road, Guanzhou 510080, China.
| | - Xian Lin
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China; Department of Anatomy & Research Center for Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, #74, Zhongshan 2nd Road, Guangzhou 510080, China.
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10
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Goodson NB, Nahreini J, Randazzo G, Uruena A, Johnson JE, Brzezinski JA. Prdm13 is required for Ebf3+ amacrine cell formation in the retina. Dev Biol 2017; 434:149-163. [PMID: 29258872 DOI: 10.1016/j.ydbio.2017.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/01/2017] [Accepted: 12/02/2017] [Indexed: 10/18/2022]
Abstract
Amacrine interneurons play a critical role in the processing of visual signals within the retina. They are highly diverse, representing 30 or more distinct subtypes. Little is known about how amacrine subtypes acquire their unique gene expression and morphological features. We characterized the gene expression pattern of the zinc-finger transcription factor Prdm13 in the mouse. Consistent with a developmental role, Prdm13 was expressed by Ptf1a+ amacrine and horizontal precursors. Over time, Prdm13 expression diverged from the transiently expressed Ptf1a and marked just a subset of amacrine cells in the adult retina. While heterogeneous, we show that most of these Prdm13+ amacrine cells express the transcription factor Ebf3 and the calcium binding protein calretinin. Loss of Prdm13 did not affect the number of amacrine cells formed during development. However, we observed a modest loss of amacrine cells and increased apoptosis that correlated with the onset timing of Ebf3 expression. Adult Prdm13 loss-of-function mice had 25% fewer amacrine cells, altered calretinin expression, and a lack of Ebf3+ amacrines. Forcing Prdm13 expression in retinal progenitor cells did not significantly increase amacrine cell formation, Ebf3 or calretinin expression, and appeared detrimental to the survival of photoreceptors. Our data show that Prdm13 is not required for amacrine fate as a class, but is essential for the formation of Ebf3+ amacrine cell subtypes. Rather than driving subtype identity, Prdm13 may act by restricting competing fate programs to maintain identity and survival.
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Affiliation(s)
- Noah B Goodson
- University of Colorado Denver, Department of Ophthalmology, United States; University of Colorado Denver, Neuroscience Graduate Program, United States
| | - Jhenya Nahreini
- University of Colorado Denver, Department of Ophthalmology, United States
| | - Grace Randazzo
- University of Colorado Denver, Department of Ophthalmology, United States
| | - Ana Uruena
- University of Texas Southwestern Medical Center, Department of Neuroscience, United States
| | - Jane E Johnson
- University of Texas Southwestern Medical Center, Department of Neuroscience, United States
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11
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Ogawa M, Saitoh F, Sudou N, Sato F, Fujieda H. Cell type-specific effects of p27 KIP1 loss on retinal development. Neural Dev 2017; 12:17. [PMID: 28931408 PMCID: PMC5607500 DOI: 10.1186/s13064-017-0094-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/14/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cyclin-dependent kinase (CDK) inhibitors play an important role in regulating cell cycle progression, cell cycle exit and cell differentiation. p27KIP1 (p27), one of the major CDK inhibitors in the retina, has been shown to control the timing of cell cycle exit of retinal progenitors. However, the precise role of this protein in retinal development remains largely unexplored. We thus analyzed p27-deficient mice to characterize the effects of p27 loss on proliferation, differentiation, and survival of retinal cells. METHODS Expression of p27 in the developing and mature mouse retina was analyzed by immunohistochemistry using antibodies against p27 and cell type-specific markers. Cell proliferation and differentiation were examined in the wild-type and p27-deficient retinas by immunohistochemistry using various cell cycle and differentiation markers. RESULTS All postmitotic retinal cell types expressed p27 in the mouse retinas. p27 loss caused extension of the period of proliferation in the developing retinas. This extra proliferation was mainly due to ectopic cell cycle reentry of differentiating cells including bipolar cells, Müller glial cells and cones, rather than persistent division of progenitors as previously suggested. Aberrant cell cycle activity of cones was followed by cone death resulting in a significant reduction in cone number in the mature p27-deficient retinas. CONCLUSIONS Although expressed in all retinal cell types, p27 is required to maintain the quiescence of specific cell types including bipolar cells, Müller glia, and cones while it is dispensable for preventing cell cycle reentry in other cell types.
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Affiliation(s)
- Mariko Ogawa
- Department of Anatomy, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Fuminori Saitoh
- Department of Anatomy, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Norihiro Sudou
- Department of Anatomy, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan
| | - Fumi Sato
- Department of Anatomy, School of Medicine, Toho University, 5-21-16 Omorinishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Hiroki Fujieda
- Department of Anatomy, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan.
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12
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Analysis of expression of transcription factors in early human retina. Int J Dev Neurosci 2017; 60:94-102. [PMID: 28377129 DOI: 10.1016/j.ijdevneu.2017.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 01/04/2017] [Accepted: 01/21/2017] [Indexed: 01/19/2023] Open
Abstract
The retina originates in the central nervous system. Due to its accessibility and simplicity, the retina has become an invaluable model for studying the basic mechanisms involved in development. To date, considerable knowledge regarding the interactions among genes that coordinate retinal development has been gained from extensive research in model animals. However, our understanding of retinal development in humans remains undeveloped. Here, we analyze the expression of transcription factors that are involved in the early development of the retina in human embryos at 6-12 weeks post-conception. Our work demonstrates that early developing neural retinas can be divided into two layers, the outer and inner neuroblast layers. Eye-field transcription factors and those related to the early development of the retina have distinct expression patterns in the two layers. Cell-type-specific transcription factors emerge at 8 weeks. These data provide clear and systemic structures for early retinal development in human.
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13
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Survival of a Novel Subset of Midbrain Dopaminergic Neurons Projecting to the Lateral Septum Is Dependent on NeuroD Proteins. J Neurosci 2017; 37:2305-2316. [PMID: 28130357 PMCID: PMC5354344 DOI: 10.1523/jneurosci.2414-16.2016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/07/2016] [Accepted: 11/30/2016] [Indexed: 11/21/2022] Open
Abstract
Midbrain dopaminergic neurons are highly heterogeneous. They differ in their connectivity and firing patterns and, therefore, in their functional properties. The molecular underpinnings of this heterogeneity are largely unknown, and there is a paucity of markers that distinguish these functional subsets. In this paper, we report the identification and characterization of a novel subset of midbrain dopaminergic neurons located in the ventral tegmental area that expresses the basic helix-loop-helix transcription factor, Neurogenic Differentiation Factor-6 (NEUROD6). Retrograde fluorogold tracing experiments demonstrate that Neurod6+ midbrain dopaminergic neurons neurons project to two distinct septal regions: the dorsal and intermediate region of the lateral septum. Loss-of-function studies in mice demonstrate that Neurod6 and the closely related family member Neurod1 are both specifically required for the survival of this lateral-septum projecting neuronal subset during development. Our findings underscore the complex organization of midbrain dopaminergic neurons and provide an entry point for future studies of the functions of the Neurod6+ subset of midbrain dopaminergic neurons.SIGNIFICANCE STATEMENT Midbrain dopaminergic neurons regulate diverse brain functions, including voluntary movement and cognitive and emotive behaviors. These neurons are heterogeneous, and distinct subsets are thought to regulate different behaviors. However, we currently lack the means to identify and modify gene function in specific subsets of midbrain dopaminergic neurons. In this study, we identify the transcription factor NEUROD6 as a specific marker for a novel subset of midbrain dopaminergic neurons in the ventral midbrain that project to the lateral septum, and we reveal essential roles for Neurod1 and Neurod6 in the survival of these neurons during development. Our findings highlight the molecular and anatomical heterogeneity of midbrain dopaminergic neurons and contribute to a better understanding of this functionally complex group of neurons.
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14
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Shekhar K, Lapan SW, Whitney IE, Tran NM, Macosko EZ, Kowalczyk M, Adiconis X, Levin JZ, Nemesh J, Goldman M, McCarroll SA, Cepko CL, Regev A, Sanes JR. Comprehensive Classification of Retinal Bipolar Neurons by Single-Cell Transcriptomics. Cell 2016; 166:1308-1323.e30. [PMID: 27565351 DOI: 10.1016/j.cell.2016.07.054] [Citation(s) in RCA: 695] [Impact Index Per Article: 86.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/10/2016] [Accepted: 07/28/2016] [Indexed: 12/15/2022]
Abstract
Patterns of gene expression can be used to characterize and classify neuronal types. It is challenging, however, to generate taxonomies that fulfill the essential criteria of being comprehensive, harmonizing with conventional classification schemes, and lacking superfluous subdivisions of genuine types. To address these challenges, we used massively parallel single-cell RNA profiling and optimized computational methods on a heterogeneous class of neurons, mouse retinal bipolar cells (BCs). From a population of ∼25,000 BCs, we derived a molecular classification that identified 15 types, including all types observed previously and two novel types, one of which has a non-canonical morphology and position. We validated the classification scheme and identified dozens of novel markers using methods that match molecular expression to cell morphology. This work provides a systematic methodology for achieving comprehensive molecular classification of neurons, identifies novel neuronal types, and uncovers transcriptional differences that distinguish types within a class.
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Affiliation(s)
- Karthik Shekhar
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Sylvain W Lapan
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Irene E Whitney
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02130, USA
| | - Nicholas M Tran
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02130, USA
| | - Evan Z Macosko
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | | | - Xian Adiconis
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Joshua Z Levin
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - James Nemesh
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Melissa Goldman
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Steven A McCarroll
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
| | - Constance L Cepko
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
| | - Aviv Regev
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Department of Biology and Koch Institute, MIT, Cambridge, MA 02139, USA.
| | - Joshua R Sanes
- Center for Brain Science and Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02130, USA.
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15
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Bachmann C, Nguyen H, Rosenbusch J, Pham L, Rabe T, Patwa M, Sokpor G, Seong RH, Ashery-Padan R, Mansouri A, Stoykova A, Staiger JF, Tuoc T. mSWI/SNF (BAF) Complexes Are Indispensable for the Neurogenesis and Development of Embryonic Olfactory Epithelium. PLoS Genet 2016; 12:e1006274. [PMID: 27611684 PMCID: PMC5017785 DOI: 10.1371/journal.pgen.1006274] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 08/03/2016] [Indexed: 01/06/2023] Open
Abstract
Neurogenesis is a key developmental event through which neurons are generated from neural stem/progenitor cells. Chromatin remodeling BAF (mSWI/SNF) complexes have been reported to play essential roles in the neurogenesis of the central nervous system. However, whether BAF complexes are required for neuron generation in the olfactory system is unknown. Here, we identified onscBAF and ornBAF complexes, which are specifically present in olfactory neural stem cells (oNSCs) and olfactory receptor neurons (ORNs), respectively. We demonstrated that BAF155 subunit is highly expressed in both oNSCs and ORNs, whereas high expression of BAF170 subunit is observed only in ORNs. We report that conditional deletion of BAF155, a core subunit in both onscBAF and ornBAF complexes, causes impaired proliferation of oNSCs as well as defective maturation and axonogenesis of ORNs in the developing olfactory epithelium (OE), while the high expression of BAF170 is important for maturation of ORNs. Interestingly, in the absence of BAF complexes in BAF155/BAF170 double-conditional knockout mice (dcKO), OE is not specified. Mechanistically, BAF complex is required for normal activation of Pax6-dependent transcriptional activity in stem cells/progenitors of the OE. Our findings unveil a novel mechanism mediated by the mSWI/SNF complex in OE neurogenesis and development.
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Affiliation(s)
| | - Huong Nguyen
- University Medical Center, Georg-August-University, Goettingen, Germany
| | | | - Linh Pham
- University Medical Center, Georg-August-University, Goettingen, Germany
| | - Tamara Rabe
- Max-Planck-Institute for Biophysical Chemistry, Goettingen, Germany
| | - Megha Patwa
- University Medical Center, Georg-August-University, Goettingen, Germany
| | - Godwin Sokpor
- University Medical Center, Georg-August-University, Goettingen, Germany
| | - Rho H. Seong
- Department of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea
| | - Ruth Ashery-Padan
- Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Tel Aviv, Israel
| | - Ahmed Mansouri
- Max-Planck-Institute for Biophysical Chemistry, Goettingen, Germany
- DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Goettingen, Germany
| | - Anastassia Stoykova
- Max-Planck-Institute for Biophysical Chemistry, Goettingen, Germany
- DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Goettingen, Germany
| | - Jochen F. Staiger
- University Medical Center, Georg-August-University, Goettingen, Germany
- DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Goettingen, Germany
| | - Tran Tuoc
- University Medical Center, Georg-August-University, Goettingen, Germany
- DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Goettingen, Germany
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16
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Differentiation/Purification Protocol for Retinal Pigment Epithelium from Mouse Induced Pluripotent Stem Cells as a Research Tool. PLoS One 2016; 11:e0158282. [PMID: 27385038 PMCID: PMC4934919 DOI: 10.1371/journal.pone.0158282] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/13/2016] [Indexed: 01/12/2023] Open
Abstract
Purpose To establish a novel protocol for differentiation of retinal pigment epithelium (RPE) with high purity from mouse induced pluripotent stem cells (iPSC). Methods Retinal progenitor cells were differentiated from mouse iPSC, and RPE differentiation was then enhanced by activation of the Wnt signaling pathway, inhibition of the fibroblast growth factor signaling pathway, and inhibition of the Rho-associated, coiled-coil containing protein kinase signaling pathway. Expanded pigmented cells were purified by plate adhesion after Accutase® treatment. Enriched cells were cultured until they developed a cobblestone appearance with cuboidal shape. The characteristics of iPS-RPE were confirmed by gene expression, immunocytochemistry, and electron microscopy. Functions and immunologic features of the iPS-RPE were also evaluated. Results We obtained iPS-RPE at high purity (approximately 98%). The iPS-RPE showed apical-basal polarity and cellular structure characteristic of RPE. Expression levels of several RPE markers were lower than those of freshly isolated mouse RPE but comparable to those of primary cultured RPE. The iPS-RPE could form tight junctions, phagocytose photoreceptor outer segments, express immune antigens, and suppress lymphocyte proliferation. Conclusion We successfully developed a differentiation/purification protocol to obtain mouse iPS-RPE. The mouse iPS-RPE can serve as an attractive tool for functional and morphological studies of RPE.
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17
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Alfano G, Shah AZ, Jeffery G, Bhattacharya SS. First insights into the expression of VAX2 in humans and its localization in the adult primate retina. Exp Eye Res 2016; 148:24-29. [DOI: 10.1016/j.exer.2016.05.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/29/2016] [Accepted: 05/09/2016] [Indexed: 01/21/2023]
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18
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Mullally M, Albrecht C, Horton M, Laboissonniere LA, Goetz JJ, Chowdhury R, Manning A, Wester AK, Bose Q, Trimarchi JM. Expression Profiling of Developing Zebrafish Retinal Cells. Zebrafish 2016; 13:272-80. [PMID: 26982811 DOI: 10.1089/zeb.2015.1184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
During retinal development, a variety of different types of neurons are produced. Understanding how each of these types of retinal nerve cells is generated is important from a developmental biology perspective. It is equally important if one is interested in how to regenerate cells after an injury or a disease. To gain more insight into how retinal neurons develop in the zebrafish, we performed single-cell mRNA profiling and in situ hybridizations (ISHs) on retinal sections and whole-mount zebrafish. Through the series of ISHs, designed and performed solely by undergraduate students in the laboratory, we were able to retrospectively identify our single-cell mRNA profiles as most likely coming from developing amacrine cells. Further analysis of these profiles will reveal genes that can be mutated using genome editing techniques. Together these studies increase our knowledge of the genes driving development of different cell types in the zebrafish retina.
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Affiliation(s)
- Madelyn Mullally
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Caitlin Albrecht
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Mary Horton
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | | | - Jillian J Goetz
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Rebecca Chowdhury
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Alicia Manning
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Andrea K Wester
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Quinton Bose
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
| | - Jeffrey M Trimarchi
- Department of Genetics, Development and Cell Biology, Iowa State University , Ames, Iowa
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19
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Kaur R, Aiken C, Morrison LC, Rao R, Del Bigio MR, Rampalli S, Werbowetski-Ogilvie T. OTX2 exhibits cell-context-dependent effects on cellular and molecular properties of human embryonic neural precursors and medulloblastoma cells. Dis Model Mech 2015; 8:1295-309. [PMID: 26398939 PMCID: PMC4610233 DOI: 10.1242/dmm.020594] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 07/29/2015] [Indexed: 12/14/2022] Open
Abstract
Medulloblastoma (MB) is the most common malignant primary pediatric brain tumor and is currently divided into four subtypes based on different genomic alterations, gene expression profiles and response to treatment: WNT, Sonic Hedgehog (SHH), Group 3 and Group 4. This extensive heterogeneity has made it difficult to assess the functional relevance of genes to malignant progression. For example, expression of the transcription factor Orthodenticle homeobox2 (OTX2) is frequently dysregulated in multiple MB variants; however, its role may be subtype specific. We recently demonstrated that neural precursors derived from transformed human embryonic stem cells (trans-hENs), but not their normal counterparts (hENs), resemble Groups 3 and 4 MB in vitro and in vivo. Here, we tested the utility of this model system as a means of dissecting the role of OTX2 in MB using gain- and loss-of-function studies in hENs and trans-hENs, respectively. Parallel experiments with MB cells revealed that OTX2 exerts inhibitory effects on hEN and SHH MB cells by regulating growth, self-renewal and migration in vitro and tumor growth in vivo. This was accompanied by decreased expression of pluripotent genes, such as SOX2, and was supported by overexpression of SOX2 in OTX2+ SHH MB and hENs that resulted in significant rescue of self-renewal and cell migration. By contrast, OTX2 is oncogenic and promotes self-renewal of trans-hENs and Groups 3 and 4 MB independent of pluripotent gene expression. Our results demonstrate a novel role for OTX2 in self-renewal and migration of hENs and MB cells and reveal a cell-context-dependent link between OTX2 and pluripotent genes. Our study underscores the value of human embryonic stem cell derivatives as alternatives to cell lines and heterogeneous patient samples for investigating the contribution of key developmental regulators to MB progression. Summary: Human embryonic stem cell neural derivatives can be used to model the molecular and cellular properties of medulloblastoma.
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Affiliation(s)
- Ravinder Kaur
- Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9
| | - Christopher Aiken
- Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9
| | - Ludivine Coudière Morrison
- Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9
| | - Radhika Rao
- Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine (inStem), NCBS-TIFR Campus, GKVK PO, Bellary Road, Bangalore 560065, India
| | - Marc R Del Bigio
- Department of Pathology, University of Manitoba, 401 Brodie Centre, 727 McDermot Avenue, Winnipeg, Manitoba, Canada, R3E 3P5 Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada
| | - Shravanti Rampalli
- Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine (inStem), NCBS-TIFR Campus, GKVK PO, Bellary Road, Bangalore 560065, India
| | - Tamra Werbowetski-Ogilvie
- Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9
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20
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Sigulinsky CL, German ML, Leung AM, Clark AM, Yun S, Levine EM. Genetic chimeras reveal the autonomy requirements for Vsx2 in embryonic retinal progenitor cells. Neural Dev 2015; 10:12. [PMID: 25927996 PMCID: PMC4450477 DOI: 10.1186/s13064-015-0039-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/14/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Vertebrate retinal development is a complex process, requiring the specification and maintenance of retinal identity, proliferative expansion of retinal progenitor cells (RPCs), and their differentiation into retinal neurons and glia. The homeobox gene Vsx2 is expressed in RPCs and required for the proper execution of this retinal program. However, our understanding of the mechanisms by which Vsx2 does this is still rudimentary. To define the autonomy requirements for Vsx2 in the regulation of RPC properties, we generated chimeric mouse embryos comprised of wild-type and Vsx2-deficient cells. RESULTS We show that Vsx2 maintains retinal identity in part through the cell-autonomous repression of the retinal pigment epithelium determinant Mitf, and that Lhx2 is required cell autonomously for the ectopic Mitf expression in Vsx2-deficient cells. We also found significant cell-nonautonomous contributions to Vsx2-mediated regulation of RPC proliferation, pointing to an important role for Vsx2 in establishing a growth-promoting extracellular environment. Additionally, we report a cell-autonomous requirement for Vsx2 in controlling when neurogenesis is initiated, indicating that Vsx2 is an important mediator of neurogenic competence. Finally, the distribution of wild-type cells shifted away from RPCs and toward retinal ganglion cell precursors in patches of high Vsx2-deficient cell density to potentially compensate for the lack of fated precursors in these areas. CONCLUSIONS Through the generation and analysis of genetic chimeras, we demonstrate that Vsx2 utilizes both cell-autonomous and cell-nonautonomous mechanisms to regulate progenitor properties in the embryonic retina. Importantly, Vsx2's role in regulating Mitf is in part separable from its role in promoting proliferation, and proliferation is excluded as the intrinsic timer that determines when neurogenesis is initiated. These findings highlight the complexity of Vsx2 function during retinal development and provide a framework for identifying the molecular mechanisms mediating these functions.
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Affiliation(s)
- Crystal L Sigulinsky
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Interdepartmental Program in Neuroscience, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Massiell L German
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Amanda M Leung
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Anna M Clark
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Edward M Levine
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
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The guanine nucleotide exchange factor Vav3 regulates differentiation of progenitor cells in the developing mouse retina. Cell Tissue Res 2014; 359:423-440. [PMID: 25501893 DOI: 10.1007/s00441-014-2050-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 11/03/2014] [Indexed: 10/24/2022]
Abstract
The seven main cell types in the mammalian retina arise from multipotent retinal progenitor cells, a process that is tightly regulated by intrinsic and extrinsic signals. However, the molecular mechanisms that control proliferation, differentiation and cell-fate decisions of retinal progenitor cells are not fully understood yet. Here, we report that the guanine nucleotide exchange factor Vav3, a regulator of Rho-GTPases, is involved in retinal development. We demonstrate that Vav3 is expressed in the mouse retina during the embryonic period. In order to study the role of Vav3 in the developing retina, we generate Vav3-deficient mice. The loss of Vav3 results in an accelerated differentiation of retinal ganglion cells and cone photoreceptors during early and late embryonic development. We provide evidence that more retinal progenitor cells express the late progenitor marker Sox9 in Vav3-deficient mice than in wild-types. This premature differentiation is compensated during the postnatal period and late-born cell types such as bipolar cells and Müller glia display normal numbers. Taken together, our data imply that Vav3 is a regulator of retinal progenitor cell differentiation, thus highlighting a novel role for guanine nucleotide exchange factors in retinogenesis.
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Trost A, Schroedl F, Marschallinger J, Rivera FJ, Bogner B, Runge C, Couillard-Despres S, Aigner L, Reitsamer HA. Characterization of dsRed2-positive cells in the doublecortin-dsRed2 transgenic adult rat retina. Histochem Cell Biol 2014; 142:601-17. [PMID: 25138677 DOI: 10.1007/s00418-014-1259-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2014] [Indexed: 10/24/2022]
Abstract
Doublecortin (DCX) is predominantly expressed in neuronal precursor cells and young immature neurons of the developing and adult brain, where it is involved in neuronal differentiation, migration and plasticity. Moreover, its expression pattern reflects neurogenesis, and transgenic DCX promoter-driven reporter models have been previously used to investigate adult neurogenesis. In this study, we characterize dsRed2 reporter protein-expressing cells in the adult retina of the transgenic DCX promoter-dsRed2 rat model, with the aim to identify cells with putative neurogenic activity. Additionally, we confirmed the expression of the dsRed2 protein in DCX-expressing cells in the adult hippocampal dentate gyrus. Adult DCX-dsRed2 rat retinas were analyzed by immunohistochemistry for expression of DCX, NF200, Brn3a, Sox2, NeuN, calbindin, calretinin, PKC-a, Otx2, ChAT, PSA-NCAM and the glial markers GFAP and CRALBP, followed by confocal laser-scanning microscopy. In addition, brain sections of transgenic rats were analyzed for dsRed2 expression and co-localization with DCX, NeuN, GFAP and Sox2 in the cortex and dentate gyrus. Endogenous DCX expression in the adult retina was confined to horizontal cells, and these cells co-expressed the DCX promoter-driven dsRed2 reporter protein. In addition, we encountered dsRed2 expression in various other cell types in the retina: retinal ganglion cells (RGCs), a subpopulation of amacrine cells, a minority of bipolar cells and in perivascular cells. Since also RGCs expressed dsRed2, the DCX-dsRed2 rat model might offer a useful tool to study RGCs in vivo under various conditions. Müller glial cells, which have previously been identified as cells with stem cell features and with neurogenic potential, did express neither endogenous DCX nor the dsRed2 reporter. However, and surprisingly, we identified a perivascular glial cell type expressing the dsRed2 reporter, enmeshed with the glia/stem cell marker GFAP and colocalizing with the neural stem cell marker Sox2. These findings suggest the so far undiscovered existence of perivascular associated cell with neural stem cell-like properties in the adult retina.
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Affiliation(s)
- A Trost
- Ophthalmology/Optometry, Paracelsus Medical University, Müllner Hauptstrasse 48, 5020, Salzburg, Austria,
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Leivada E, Boeckx C. Schizophrenia and cortical blindness: protective effects and implications for language. Front Hum Neurosci 2014; 8:940. [PMID: 25506321 PMCID: PMC4246684 DOI: 10.3389/fnhum.2014.00940] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 11/04/2014] [Indexed: 01/20/2023] Open
Abstract
The repeatedly noted absence of case-reports of individuals with schizophrenia and congenital/early developed blindness has led several authors to argue that the latter can confer protective effects against the former. In this work, we present a number of relevant case-reports from different syndromes that show comorbidity of congenital and early blindness with schizophrenia. On the basis of these reports, we argue that a distinction between different types of blindness in terms of the origin of the visual deficit, cortical or peripheral, is crucial for understanding the observed patterns of comorbidity. We discuss the genetic underpinnings and the brain structures involved in schizophrenia and blindness, with insights from language processing, laying emphasis on the three structures that particularly stand out: the occipital cortex, the lateral geniculate nucleus (LGN), and the pulvinar. Last, we build on previous literature on the nature of the protective effects in order to offer novel insights into the nature of the protection mechanism from the perspective of the brain structures involved in each type of blindness.
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Affiliation(s)
- Evelina Leivada
- Department of Linguistics, Universitat de BarcelonaBarcelona, Spain
| | - Cedric Boeckx
- Department of Linguistics, Universitat de BarcelonaBarcelona, Spain
- Catalan Institute for Advanced Studies and Research (ICREA)Barcelona, Spain
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Zou M, Luo H, Xiang M. Selective neuronal lineages derived from Dll4-expressing progenitors/precursors in the retina and spinal cord. Dev Dyn 2014; 244:86-97. [PMID: 25179941 DOI: 10.1002/dvdy.24185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND During retinal and spinal cord neurogenesis, Notch signaling plays crucial roles in regulating proliferation and differentiation of progenitor cells. One of the Notch ligands, Delta-like 4 (Dll4), has been shown to be expressed in subsets of retinal and spinal cord progenitors/precursors and involved in neuronal subtype specification. However, it remains to be determined whether Dll4 expression has any progenitor/precursor-specificity contributing to its functional specificity during neural development. RESULTS We generated a Dll4-Cre BAC transgenic mouse line that drives Cre recombinase expression mimicking that of the endogenous Dll4 in the developing retina and spinal cord. By fate-mapping analysis, we found that Dll4-expressing progenitors/precursors give rise to essentially all cone, amacrine and horizontal cells, a large portion of rod and ganglion cells, but only few bipolar and Müller cells. In the spinal cord, Dll4-expressing progenitors/precursors generate almost all V2a and V2c cells while producing only a fraction of the cells for other interneuron and motor neuron subtypes along the dorsoventral axis. CONCLUSIONS Our data suggest that selective expression of Dll4 in progenitors/precursors contributes to its functional specificity in neuronal specification and that the Dll4-Cre line is a valuable tool for gene manipulation to study Notch signaling.
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Affiliation(s)
- Min Zou
- Center for Advanced Biotechnology and Medicine and Department of Pediatrics, Rutgers University-Robert Wood Johnson Medical School, Piscataway, New Jersey
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25
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Tran NM, Chen S. Mechanisms of blindness: animal models provide insight into distinct CRX-associated retinopathies. Dev Dyn 2014; 243:1153-66. [PMID: 24888636 DOI: 10.1002/dvdy.24151] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/24/2014] [Accepted: 05/10/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The homeodomain transcription factor CRX is a crucial regulator of mammalian photoreceptor gene expression. Mutations in the human CRX gene are associated with dominant inherited retinopathies Retinitis Pigmentosa (RP), Cone-Rod Dystrophy (CoRD), and Leber Congenital Amaurosis (LCA), of varying severity. In vitro and in vivo assessment of mutant CRX proteins have revealed pathogenic mechanisms for several mutations, but no comprehensive mutation-disease correlation has yet been reported. RESULTS Here we describe four different classes of disease-causing CRX mutations, characterized by mutation type, pathogenetic mechanism, and the molecular activity of the mutant protein: (1) hypomorphic missense mutations with reduced DNA binding, (2) antimorphic missense mutations with variable DNA binding, (3) antimorphic frameshift/nonsense mutations with intact DNA binding, and (4) antimorphic frameshift mutations with reduced DNA binding. Mammalian models representing three of these classes have been characterized. CONCLUSIONS Models carrying Class I mutations display a mild dominant retinal phenotype and recessive LCA, while models carrying Class III and IV mutations display characteristically distinct dominant LCA phenotypes. These animal models also reveal unexpected pathogenic mechanisms underlying CRX-associated retinopathies. The complexity of genotype-phenotype correlation for CRX-associated diseases highlights the value of developing comprehensive "true-to-disease" animal models for understanding pathologic mechanisms and testing novel therapeutic approaches.
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Affiliation(s)
- Nicholas M Tran
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, Missouri
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Goetz JJ, Farris C, Chowdhury R, Trimarchi JM. Making of a retinal cell: insights into retinal cell-fate determination. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 308:273-321. [PMID: 24411174 DOI: 10.1016/b978-0-12-800097-7.00007-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Understanding the process by which an uncommitted dividing cell produces particular specialized cells within a tissue remains a fundamental question in developmental biology. Many tissues are well suited for cell-fate studies, but perhaps none more so than the developing retina. Traditionally, experiments using the retina have been designed to elucidate the influence that individual environmental signals or transcription factors can have on cell-fate decisions. Despite a substantial amount of information gained through these studies, there is still much that we do not yet understand about how cell fate is controlled on a systems level. In addition, new factors such as noncoding RNAs and regulators of chromatin have been shown to play roles in cell-fate determination and with the advent of "omics" technology more factors will most likely be identified. In this chapter we summarize both the traditional view of retinal cell-fate determination and introduce some new ideas that are providing a challenge to the older way of thinking about the acquisition of cell fates.
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Affiliation(s)
- Jillian J Goetz
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Caitlin Farris
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Rebecca Chowdhury
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Jeffrey M Trimarchi
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA.
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Changes in Otx2 and parvalbumin immunoreactivity in the superior colliculus in the platelet-derived growth factor receptor-β knockout mice. BIOMED RESEARCH INTERNATIONAL 2013; 2013:848265. [PMID: 24319691 PMCID: PMC3844215 DOI: 10.1155/2013/848265] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 09/30/2013] [Indexed: 12/11/2022]
Abstract
The superior colliculus (SC), a relay nucleus in the subcortical visual pathways, is implicated in socioemotional behaviors. Homeoprotein Otx2 and β subunit of receptors of platelet-derived growth factor (PDGFR-β) have been suggested to play an important role in development of the visual system and development and maturation of GABAergic neurons. Although PDGFR-β-knockout (KO) mice displayed socio-emotional deficits associated with parvalbumin (PV-)immunoreactive (IR) neurons, their anatomical bases in the SC were unknown. In the present study, Otx2 and PV-immunolabeling in the adult mouse SC were investigated in the PDGFR-β KO mice. Although there were no differences in distribution patterns of Otx2 and PV-IR cells between the wild type and PDGFR-β KO mice, the mean numbers of both of the Otx2- and PV-IR cells were significantly reduced in the PDGFR-β KO mice. Furthermore, average diameters of Otx2- and PV-IR cells were significantly reduced in the PDGFR-β KO mice. These findings suggest that PDGFR-β plays a critical role in the functional development of the SC through its effects on Otx2- and PV-IR cells, provided specific roles of Otx2 protein and PV-IR cells in the development of SC neurons and visual information processing, respectively.
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Brzezinski JA, Uoon Park K, Reh TA. Blimp1 (Prdm1) prevents re-specification of photoreceptors into retinal bipolar cells by restricting competence. Dev Biol 2013; 384:194-204. [PMID: 24125957 DOI: 10.1016/j.ydbio.2013.10.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/02/2013] [Accepted: 10/04/2013] [Indexed: 12/14/2022]
Abstract
During retinal development, photoreceptors and bipolar cells express the transcription factor Otx2. Blimp1 is transiently expressed in Otx2+ cells. Blimp1 deletion results in excess bipolar cell formation at the expense of photoreceptors. In principle, Blimp1 could be expressed only in Otx2+ cells that are committed to photoreceptor fate. Alternatively, Blimp1 could be expressed broadly in Otx2+ cells and silenced to allow bipolar cell development. To distinguish between these alternatives, we followed the fate of Blimp1 expressing cells using Blimp1-Cre mice and Lox-Stop-Lox reporter strains. We observed that Blimp1+ cells gave rise to all photoreceptors, but also to one third of bipolar cells, consistent with the latter alternative: that Blimp1 inhibits bipolar competence in Otx2+ cells and must be silenced to allow bipolar cell generation. To further test this hypothesis, we looked for transitioning rod photoreceptors in Blimp1 conditional knock-out (CKO) mice carrying the NRL-GFP transgene, which specifically labels rods. Control animals lacked NRL-GFP+ bipolar cells. In contrast, about half of the precociously generated bipolar cells in Blimp1 CKO mice co-expressed GFP, suggesting that rods become re-specified as bipolar cells. Birthdating analyses in control and Blimp1 CKO mice showed that bipolar cells were birthdated as early as E13.5 in Blimp1 CKO mice, five days before this cell type was generated in the wild-type retina. Taken together, our data suggest that early Otx2+ cells upregulate photoreceptor and bipolar genes, existing in a bistable state. Blimp1 likely forms a cross-repressive network with pro-bipolar factors such that the winner of this interaction stabilizes the photoreceptor or bipolar state, respectively.
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Affiliation(s)
- Joseph A Brzezinski
- Department of Ophthalmology. University of Colorado School of Medicine, Aurora, CO 80045, USA.
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Ballios BG, Clarke L, Coles BLK, Shoichet MS, Van Der Kooy D. The adult retinal stem cell is a rare cell in the ciliary epithelium whose progeny can differentiate into photoreceptors. Biol Open 2012; 1:237-46. [PMID: 23213414 PMCID: PMC3507281 DOI: 10.1242/bio.2012027] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Self-renewing, multipotential retinal stem cells (RSCs) reside in the pigmented ciliary epithelium of the peripheral retina in adult mammals. RSCs can give rise to rhodopsin positive-cells, which can integrate into early postnatal retina, and represent a potentially useful option for cellular therapy. The ability to purify a stem cell population and direct the differentiation toward a particular cell lineage is a challenge facing the application of stem cells in regenerative medicine. Here we use cell sorting to prospectively enrich mouse RSCs based on size, granularity and low expression of P-cadherin and demonstrate that only rare cells with defined properties proliferate to form colonies. We show that clonally-derived mouse and human RSC progeny are multipotent and can differentiate into mature rhodopsin-positive cells with high efficiency using combinations of exogenous culture additives known to influence neural retinal development, including taurine and retinoic acid. This directed RSC differentiation follows the temporal sequence of photoreceptor differentiation in vivo, and the cells exhibit morphology, protein and gene expression consistent with primary cultures of rods in vitro. These results demonstrate that the RSC, an adult stem cell, can be enriched and directed to produce photoreceptors as a first step toward a targeted cell replacement strategy to treat retinal degenerative disease.
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Affiliation(s)
- Brian G Ballios
- Institute of Medical Science, University of Toronto, 1 King's College Circle , Toronto, Ontario M5S 1A8 , Canada
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The role of Zic family zinc finger transcription factors in the proliferation and differentiation of retinal progenitor cells. Biochem Biophys Res Commun 2011; 415:42-7. [PMID: 22024047 DOI: 10.1016/j.bbrc.2011.10.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 10/03/2011] [Indexed: 02/07/2023]
Abstract
Members of the Zic family of zinc finger transcription factors play critical roles in a variety of developmental processes. Using DNA microarray analysis, we found that Zics are strongly expressed in SSEA-1-positive early retinal progenitors in the peripheral region of the mouse retina. Reverse-transcription polymerase chain reaction using mRNA from the retina at various developmental stages showed that Zic1 and Zic2 are expressed in the embryonic retina and then gradually disappear during retinal development. Zic3 is also expressed in the embryonic retina; its expression level slightly decreases but it is expressed until adulthood. We overexpressed Zic1, Zic2, or Zic3 in retinal progenitors at embryonic day 17.5 and cultured the retina as explants for 2 weeks. The number of rod photoreceptors was fewer than in the control, but no other cell types showed significant differences between control and Zic overexpressing cells. The proliferation activity of normal retinal progenitors decreased after 5 days in culture, as observed in normal in vivo developmental processes. However, Zic expressing retinal cells continued to proliferate at days 5 and 7, suggesting that Zics sustain the proliferation activities of retinal progenitor cells. Since the effects of Zic1, 2, and 3 are indistinguishable in terms of differentiation and proliferation of retinal progenitors, the redundant function of Zics in retinal development is suggested.
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Emerson MM, Cepko CL. Identification of a retina-specific Otx2 enhancer element active in immature developing photoreceptors. Dev Biol 2011; 360:241-55. [PMID: 21963459 DOI: 10.1016/j.ydbio.2011.09.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2011] [Revised: 09/09/2011] [Accepted: 09/13/2011] [Indexed: 01/20/2023]
Abstract
The homeodomain protein, Otx2, is a critical regulator of vertebrate photoreceptor genesis. However, the genetic elements that define the expression of Otx2 during photoreceptor development are unknown. Therefore, we sought to identify an Otx2 enhancer element that functions in photoreceptor development in order to better understand this specification event. Using the technique of electroporation, we tested a number of evolutionarily conserved elements (ECRs) for expression in the developing retina, and identified ECR2 as having robust activity in the retina. We have characterized this element using a number of assays, including Cre-fate mapping experiments. We found that ECR2 recapitulates expression/function of Otx2 primarily in newly postmitotic photoreceptor cells (PRs), as well as in a subset of retinal progenitor cells (RPCs). ECR2 was also found to be expressed in a subset of horizontal cells (HCs), in keeping with the role of Otx2 in HC development. Furthermore, we determined that the ECR2 element is not active in other Otx2-positive cells such as retinal bipolar cells (BPs), retinal pigmented epithelium (RPE), or the tectum, suggesting that the transcriptional networks controlling Otx2 expression in these cells are unique from those of developing PRs and HCs. These results reveal a distinct molecular state in dividing retinal cells and their newly postmitotic progeny, and provide genetic access to an early and critical transcriptional node involved in the genesis of vertebrate PRs.
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Affiliation(s)
- Mark M Emerson
- Department of Genetics, Department of Ophthamology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
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Zhang X, Serb JM, Greenlee MHW. Mouse retinal development: a dark horse model for systems biology research. Bioinform Biol Insights 2011; 5:99-113. [PMID: 21698072 PMCID: PMC3118678 DOI: 10.4137/bbi.s6930] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The developing retina is an excellent model to study cellular fate determination and differentiation in the context of a complex tissue. Over the last decade, many basic principles and key genes that underlie these processes have been experimentally identified. In this review, we construct network models to summarize known gene interactions that underlie determination and fundamentally affect differentiation of each retinal cell type. These networks can act as a scaffold to assemble subsequent discoveries. In addition, these summary networks provide a rational segue to systems biology approaches necessary to understand the many events leading to appropriate cellular determination and differentiation in the developing retina and other complex tissues.
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Affiliation(s)
- Xia Zhang
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA
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Kokkinopoulos I, Shahabi G, Colman A, Jeffery G. Mature peripheral RPE cells have an intrinsic capacity to proliferate; a potential regulatory mechanism for age-related cell loss. PLoS One 2011; 6:e18921. [PMID: 21526120 PMCID: PMC3081302 DOI: 10.1371/journal.pone.0018921] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 03/25/2011] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mammalian peripheral retinal pigmented epithelium (RPE) cells proliferate throughout life, while central cells are senescent. It is thought that some peripheral cells migrate centrally to correct age-related central RPE loss. METHODOLOGY/PRINCIPAL FINDINGS We ask whether this proliferative capacity is intrinsic to such cells and whether cells located centrally produce diffusible signals imposing senescence upon the former once migrated. We also ask whether there are regional differences in expression patterns of key genes involved in these features between the centre and the periphery in vivo and in vitro. Low density RPE cultures obtained from adult mice revealed significantly greater levels of proliferation when derived from peripheral compared to central tissue, but this significance declined with increasing culture density. Further, exposure to centrally conditioned media had no influence on proliferation in peripheral RPE cell cultures at the concentrations examined. Central cells expressed significantly higher levels of E-Cadherin revealing a tighter cell adhesion than in the peripheral regions. Fluorescence-labelled staining for E-Cadherin, F-actin and ZO-1 in vivo revealed different patterns with significantly increased expression on central RPE cells than those in the periphery or differences in junctional morphology. A range of other genes were investigated both in vivo and in vitro associated with RPE proliferation in order to identify gene expression differences between the centre and the periphery. Specifically, the cell cycle inhibitor p27(Kip1) was significantly elevated in central senescent regions in vivo and mTOR, associated with RPE cell senescence, was significantly elevated in the centre in comparison to the periphery. CONCLUSIONS These data show that the proliferative capacity of peripheral RPE cells is intrinsic and cell-autonomous in adult mice. These differences between centre and periphery are reflected in distinct patterns in junctional markers. The regional proliferation differences may be inversely dependent to cell-cell contact.
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Affiliation(s)
- Ioannis Kokkinopoulos
- Institute of Ophthalmology, University College London, London, United Kingdom
- School of Biomedical and Health Sciences Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Golnaz Shahabi
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Alan Colman
- Singapore Stem Cell Consortium, Singapore, Singapore
| | - Glen Jeffery
- Institute of Ophthalmology, University College London, London, United Kingdom
- * E-mail:
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Dixit R, Zimmer C, Waclaw RR, Mattar P, Shaker T, Kovach C, Logan C, Campbell K, Guillemot F, Schuurmans C. Ascl1 Participates in Cajal–Retzius Cell Development in the Neocortex. Cereb Cortex 2011; 21:2599-611. [DOI: 10.1093/cercor/bhr046] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Westenskow PD, McKean JB, Kubo F, Nakagawa S, Fuhrmann S. Ectopic Mitf in the embryonic chick retina by co-transfection of β-catenin and Otx2. Invest Ophthalmol Vis Sci 2010; 51:5328-35. [PMID: 20463321 PMCID: PMC3066625 DOI: 10.1167/iovs.09-5015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 03/26/2010] [Accepted: 04/15/2010] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Development of the retinal pigment epithelium (RPE) is controlled by intrinsic and extrinsic regulators including orthodenticle homeobox 2 (Otx2) and the Wnt/β-catenin pathway, respectively. Otx2 and β-catenin are necessary for the expression of the RPE key regulator microphthalmia-associated transcription factor (Mitf); however, neither factor is sufficient to promote Mitf expression in vivo. The study was conducted to determine whether Otx2 and β-catenin act in a combinatorial manner and tested whether co-expression in the presumptive chick retina induces ectopic Mitf expression. METHODS The sufficiency of Wnt/β-catenin activation and/or Otx2 expression to induce RPE-specific gene expression was examined in chick optic vesicle explant cultures or in the presumptive neural retina using in ovo-electroporation. Luciferase assays were used to examine the transactivation potentials of Otx2 and β-catenin on the Mitf-D enhancer and autoregulation of the Mitf-D and Otx2T0 enhancers. RESULTS In optic vesicles explant cultures, RPE-specific gene expression was activated by lithium chloride, a Wnt/β-catenin agonist. However, in vivo, Mitf was induced only in the presumptive retina if both β-catenin and Otx2 are co-expressed. Furthermore, both Mitf and Otx2 can autoregulate their own enhancers in vitro. CONCLUSIONS The present study provides evidence that β-catenin and Otx2 are sufficient, at least in part, to convert retinal progenitor cells into presumptive RPE cells expressing Mitf. Otx2 may act as a competence factor that allows RPE specification in concert with additional RPE-promoting factors such as β-catenin.
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Affiliation(s)
- Peter D. Westenskow
- From the Department of Ophthalmology and Visual Sciences, Moran Eye Center, and
- the Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah; and
| | - Jon B. McKean
- From the Department of Ophthalmology and Visual Sciences, Moran Eye Center, and
| | - Fumi Kubo
- the RIKEN Advanced Science Institute, Wako, Saitama, Japan
| | | | - Sabine Fuhrmann
- From the Department of Ophthalmology and Visual Sciences, Moran Eye Center, and
- the Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah; and
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Inoue T, Coles BLK, Dorval K, Bremner R, Bessho Y, Kageyama R, Hino S, Matsuoka M, Craft CM, McInnes RR, Tremblay F, Prusky GT, van der Kooy D. Maximizing functional photoreceptor differentiation from adult human retinal stem cells. Stem Cells 2010; 28:489-500. [PMID: 20014120 DOI: 10.1002/stem.279] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Retinal stem cells (RSCs) are present in the ciliary margin of the adult human eye and can give rise to all retinal cell types. Here we show that modulation of retinal transcription factor gene expression in human RSCs greatly enriches photoreceptor progeny, and that strong enrichment was obtained with the combined transduction of OTX2 and CRX together with the modulation of CHX10. When these genetically modified human RSC progeny are transplanted into mouse eyes, their retinal integration and differentiation is superior to unmodified RSC progeny. Moreover, electrophysiologic and behavioral tests show that these transplanted cells promote functional recovery in transducin mutant mice. This study suggests that gene modulation in human RSCs may provide a source of photoreceptor cells for the treatment of photoreceptor disease.
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Affiliation(s)
- Tomoyuki Inoue
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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Bassett EA, Williams T, Zacharias AL, Gage PJ, Fuhrmann S, West-Mays JA. AP-2alpha knockout mice exhibit optic cup patterning defects and failure of optic stalk morphogenesis. Hum Mol Genet 2010; 19:1791-804. [PMID: 20150232 DOI: 10.1093/hmg/ddq060] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Appropriate development of the retina and optic nerve requires that the forebrain-derived optic neuroepithelium undergoes a precisely coordinated sequence of patterning and morphogenetic events, processes which are highly influenced by signals from adjacent tissues. Our previous work has suggested that transcription factor activating protein-2 alpha (AP-2alpha; Tcfap2a) has a non-cell autonomous role in optic cup (OC) development; however, it remained unclear how OC abnormalities in AP-2alpha knockout (KO) mice arise at the morphological and molecular level. In this study, we show that patterning and morphogenetic defects in the AP-2alpha KO optic neuroepithelium begin at the optic vesicle stage. During subsequent OC formation, ectopic neural retina and optic stalk-like tissue replaced regions of retinal pigment epithelium. AP-2alpha KO eyes also displayed coloboma in the ventral retina, and a rare phenotype in which the optic stalk completely failed to extend, causing the OCs to be drawn inward to the midline. We detected evidence of increased sonic hedgehog signaling in the AP-2alpha KO forebrain neuroepithelium, which likely contributed to multiple aspects of the ocular phenotype, including expansion of PAX2-positive optic stalk-like tissue into the OC. Our data suggest that loss of AP-2alpha in multiple tissues in the craniofacial region leads to severe OC and optic stalk abnormalities by disturbing the tissue-tissue interactions required for ocular development. In view of recent data showing that mutations in human TFAP2A result in similar eye defects, the current findings demonstrate that AP-2alpha KO mice provide a valuable model for human ocular disease.
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Affiliation(s)
- Erin A Bassett
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada
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Rapicavoli NA, Blackshaw S. New meaning in the message: Noncoding RNAs and their role in retinal development. Dev Dyn 2009; 238:2103-14. [DOI: 10.1002/dvdy.21844] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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Das G, Choi Y, Sicinski P, Levine EM. Cyclin D1 fine-tunes the neurogenic output of embryonic retinal progenitor cells. Neural Dev 2009; 4:15. [PMID: 19416500 PMCID: PMC2694796 DOI: 10.1186/1749-8104-4-15] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 05/05/2009] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Maintaining the correct balance of proliferation versus differentiation in retinal progenitor cells (RPCs) is essential for proper development of the retina. The cell cycle regulator cyclin D1 is expressed in RPCs, and mice with a targeted null allele at the cyclin D1 locus (Ccnd1-/-) have microphthalmia and hypocellular retinas, the latter phenotype attributed to reduced RPC proliferation and increased photoreceptor cell death during the postnatal period. How cyclin D1 influences RPC behavior, especially during the embryonic period, is unclear. RESULTS In this study, we show that embryonic RPCs lacking cyclin D1 progress through the cell cycle at a slower rate and exit the cell cycle at a faster rate. Consistent with enhanced cell cycle exit, the relative proportions of cell types born in the embryonic period, such as retinal ganglion cells and photoreceptor cells, are increased. Unexpectedly, cyclin D1 deficiency decreases the proportions of other early born retinal neurons, namely horizontal cells and specific amacrine cell types. We also found that the laminar positioning of horizontal cells and other cell types is altered in the absence of cyclin D1. Genetically replacing cyclin D1 with cyclin D2 is not efficient at correcting the phenotypes due to the cyclin D1 deficiency, which suggests the D-cyclins are not fully redundant. Replacement with cyclin E or inactivation of cyclin-dependent kinase inhibitor p27Kip1 restores the balance of RPCs and retinal cell types to more normal distributions, which suggests that regulation of the retinoblastoma pathway is an important function for cyclin D1 during embryonic retinal development. CONCLUSION Our findings show that cyclin D1 has important roles in RPC cell cycle regulation and retinal histogenesis. The reduction in the RPC population due to a longer cell cycle time and to an enhanced rate of cell cycle exit are likely to be the primary factors driving retinal hypocellularity and altered output of precursor populations in the embryonic Ccnd1-/- retina.
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Affiliation(s)
- Gaurav Das
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA.
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Sugiyama S, Prochiantz A, Hensch TK. From brain formation to plasticity: insights on Otx2 homeoprotein. Dev Growth Differ 2009; 51:369-77. [PMID: 19298552 DOI: 10.1111/j.1440-169x.2009.01093.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The shaping of neuronal circuits is essential during postnatal brain development. A window of neuronal remodeling by sensory experience typically occurs during a unique time in early life. The many types of behavior and perception, like human language, birdsong, hearing and vision are refined by experience during these distinct 'critical periods'. The onset of critical periods for vision is delayed in animals that remain in complete darkness from birth. It is then predicted that a 'messenger' within the visual pathway signals the amount of sensory experience that has occurred. Our recent results indicate that Otx2 homeoprotein, an essential morphogen for embryonic head formation, is reused later in life as this 'messenger' for critical period plasticity. The homeoprotein is stimulated by visual experience to propagate into the visual cortex, where it is internalized by GABAergic interneurons, especially Parvalbumin-positive cells (PV-cells). Otx2 promotes the maturation of PV-cells, consequently activating critical period onset in the visual cortex. Here, we discuss recent data that are beginning to illuminate the physiological function of non-cell autonomous homeoproteins, as well as the restriction of their transfer to PV-cells in vivo.
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Affiliation(s)
- Sayaka Sugiyama
- Department of Neurology, FM Kirby Neurobiology Center, Children's Hospital Boston, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
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Koshimizu H, Senatorov V, Loh YP, Gozes I. Neuroprotective protein and carboxypeptidase E. J Mol Neurosci 2009; 39:1-8. [PMID: 19165633 DOI: 10.1007/s12031-008-9164-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 11/09/2008] [Indexed: 12/14/2022]
Abstract
This review outlines the neuroprotective activities and structural specificities of two distinct proteins, activity-dependent neuroprotective protein, a protein assigned transcription factor/chromatin remodeling activity, and carboxypeptidase E, a classic exopeptidase. Future studies will elucidate how these two versatile proteins converge onto a similar endpoint: neuroprotection.
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Affiliation(s)
- Hisatsugu Koshimizu
- Section on Cellular Neurobiology, Program on Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Esumi N, Kachi S, Hackler L, Masuda T, Yang Z, Campochiaro PA, Zack DJ. BEST1 expression in the retinal pigment epithelium is modulated by OTX family members. Hum Mol Genet 2008; 18:128-41. [PMID: 18849347 DOI: 10.1093/hmg/ddn323] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A number of genes preferentially expressed in the retinal pigment epithelium (RPE) are associated with retinal degenerative disease. One of these, BEST1, encodes bestrophin-1, a protein that when mutated causes Best macular dystrophy. As a model for RPE gene regulation, we have been studying the mechanisms that control BEST1 expression, and recently demonstrated that members of the MITF-TFE family modulate BEST1 transcription. The human BEST1 upstream region from -154 to +38 bp is sufficient to direct expression in the RPE, and positive-regulatory elements exist between -154 and -104 bp. Here, we show that the -154 to -104 bp region is necessary for RPE expression in transgenic mice and contains a predicted OTX-binding site (Site 1). Since another non-canonical OTX site (Site 2) is located nearby, we tested the function of these sites using BEST1 promoter/luciferase constructs by in vivo electroporation and found that mutation of both sites reduces promoter activity. Three OTX family proteins - OTX1, OTX2 and CRX - bound to both Sites 1 and 2 in vitro, and all of them increased BEST1 promoter activity. Surprisingly, we found that human and bovine RPE expressed not only OTX2 but also CRX, the CRX genomic region in bovine RPE was hypersensitive to DNase I, consistent with active transcription, and that both OTX2 and CRX bound to the BEST1 proximal promoter in vivo. These results demonstrate for the first time CRX expression in the RPE, and suggest that OTX2 and CRX may act as positive modulators of the BEST1 promoter in the RPE.
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Affiliation(s)
- Noriko Esumi
- The Guerrieri Center for Genetic Engineering and Molecular Ophthalmology at The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287-9289, USA
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Elucidating the phenomenon of HESC-derived RPE: anatomy of cell genesis, expansion and retinal transplantation. Exp Neurol 2008; 214:347-61. [PMID: 18926821 DOI: 10.1016/j.expneurol.2008.09.007] [Citation(s) in RCA: 216] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 08/12/2008] [Accepted: 09/05/2008] [Indexed: 01/12/2023]
Abstract
Healthy Retinal Pigment Epithelium (RPE) cells are required for proper visual function and the phenomenon of RPE derivation from Human Embryonic Stem Cells (HESC) holds great potential for the treatment of retinal diseases. However, little is known about formation, expansion and expression profile of RPE-like cells derived from HESC (HESC-RPE). By studying the genesis of pigmented foci we identified OTX1/2-positive cell types as potential HESC-RPE precursors. When pigmented foci were excised from culture, HESC-RPE expanded to form extensive monolayers, with pigmented cells at the leading edge assuming a precursor role: de-pigmenting, proliferating, expressing keratin 8 and subsequently re-differentiating. As they expanded and differentiated in vitro, HESC-RPE expressed markers of both developing and mature RPE cells which included OTX1/2, Pax6, PMEL17 and at low levels, RPE65. In vitro, without signals from a developing retinal environment, HESC-RPE could produce regular, polarised monolayers with developmentally important apical and basal features. Following transplantation of HESC-RPE into the degenerating retinal environment of Royal College of Surgeons (RCS) dystrophic rats, the cells survived in the subretinal space, where they maintained low levels of RPE65 expression and remained out of the cell cycle. The HESC-RPE cells responded to the in vivo environment by downregulating Pax6, while maintaining expression of other markers. The presence of rhodopsin-positive material within grafted HESC-RPE indicates that in the future, homogenous transplants of this cell type may be capable of supporting visual function following retinal dystrophy.
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Huang ZJ, Di Cristo G. Time to change: retina sends a messenger to promote plasticity in visual cortex. Neuron 2008; 59:355-8. [PMID: 18701062 DOI: 10.1016/j.neuron.2008.07.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Maturation of GABA inhibitory circuitry in primary visual cortex activates the critical period of plasticity, but the underlying mechanisms are not well understood. In the August 8th issue of Cell, Sugiyama et al. demonstrate that visual experience promotes the passage of a retina-derived homeoprotein along the visual pathway, which nurtures subclasses of cortical interneurons implicated in regulating critical period plasticity.
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Affiliation(s)
- Z Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
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45
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A core paired-type and POU homeodomain-containing transcription factor program drives retinal bipolar cell gene expression. J Neurosci 2008; 28:7748-64. [PMID: 18667607 DOI: 10.1523/jneurosci.0397-08.2008] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The diversity of cell types found within the vertebrate CNS arises in part from action of complex transcriptional programs. In the retina, the programs driving diversification of various cell types have not been completely elucidated. To investigate gene regulatory networks that underlie formation and function of one retinal circuit component, the bipolar cell, transcriptional regulation of three bipolar cell-enriched genes was analyzed. Using in vivo retinal DNA transfection and reporter gene constructs, a 200 bp Grm6 enhancer sequence, a 445 bp Cabp5 promoter sequence, and a 164 bp Chx10 enhancer sequence, were defined, each driving reporter expression specifically in distinct but overlapping bipolar cell subtypes. Bioinformatic analysis of sequences revealed the presence of potential paired-type and POU homeodomain-containing transcription factor binding sites, which were shown to be critical for reporter expression through deletion studies. The paired-type homeodomain transcription factors (TFs) Crx and Otx2 and the POU homeodomain factor Brn2 are expressed in bipolar cells and interacted with the predicted binding sequences as assessed by electrophoretic mobility shift assay. Grm6, Cabp5, and Chx10 reporter activity was reduced in Otx2 loss-of-function retinas. Endogenous gene expression of bipolar cell molecular markers was also dependent on paired-type homeodomain-containing TFs, as assessed by RNA in situ hybridization and reverse transcription-PCR in mutant retinas. Cabp5 and Chx10 reporter expression was reduced in dominant-negative Brn2-transfected retinas. The paired-type and POU homeodomain-containing TFs Otx2 and Brn2 together appear to play a common role in regulating gene expression in retinal bipolar cells.
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Experience-Dependent Transfer of Otx2 Homeoprotein into the Visual Cortex Activates Postnatal Plasticity. Cell 2008; 134:508-20. [DOI: 10.1016/j.cell.2008.05.054] [Citation(s) in RCA: 363] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2007] [Revised: 04/22/2008] [Accepted: 05/05/2008] [Indexed: 11/21/2022]
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Fuhrmann S, Riesenberg AN, Mathiesen AM, Brown EC, Vetter ML, Brown NL. Characterization of a transient TCF/LEF-responsive progenitor population in the embryonic mouse retina. Invest Ophthalmol Vis Sci 2008; 50:432-40. [PMID: 18599572 DOI: 10.1167/iovs.08-2270] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE High mobility group (HMG) transcription factors of the T-cell-specific transcription factor/lymphoid enhancer binding factor (TCF/LEF) family are a class of intrinsic regulators that are dynamically expressed in the embryonic mouse retina. Activation of TCF/LEFs is a hallmark of the Wnt/beta-catenin pathway; however, the requirement for Wnt/beta-catenin and noncanonical Wnt signaling during mammalian retinal development remains unclear. The goal of the study was to characterize more fully a TCF/LEF-responsive retinal progenitor population in the mouse embryo and to correlate this with Wnt/beta-catenin signaling. METHODS TCF/LEF activation was analyzed in the TOPgal (TCF optimal promoter) reporter mouse at embryonic ages and compared to Axin2 mRNA expression, an endogenous readout of Wnt/beta-catenin signaling. Reporter expression was also examined in embryos with a retina-specific deletion of the beta-catenin gene (Ctnnb1), using Six3-Cre transgenic mice. Finally, the extent to which TOPgal cells coexpress cell cycle proteins, basic helix-loop-helix (bHLH) transcription factors, and other retinal cell markers was tested by double immunohistochemistry. RESULTS TOPgal reporter activation occurred transiently in a subpopulation of embryonic retinal progenitor cells. Axin2 was not expressed in the central retina, and TOPgal reporter expression persisted in the absence of beta-catenin. Although a proportion of TOPgal-labeled cells were proliferative, most coexpressed the cyclin-dependent kinase inhibitor p27/Kip1. CONCLUSIONS TOPgal cells give rise to the four earliest cell types: ganglion, amacrine, horizontal, and photoreceptor. TCF/LEF activation in the central retina does not correlate with Wnt/beta-catenin signaling, pointing to an alternate role for this transcription factor family during retinal development.
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Affiliation(s)
- Sabine Fuhrmann
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah 84132, USA.
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Kim DS, Ross SE, Trimarchi JM, Aach J, Greenberg ME, Cepko CL. Identification of molecular markers of bipolar cells in the murine retina. J Comp Neurol 2008; 507:1795-810. [PMID: 18260140 PMCID: PMC2665264 DOI: 10.1002/cne.21639] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Retinal bipolar neurons serve as relay interneurons that connect rod and cone photoreceptor cells to amacrine and ganglion cells. They exhibit diverse morphologies essential for correct routing of photoreceptor cell signals to specific postsynaptic amacrine and ganglion cells. The development and physiology of these interneurons have not been completely defined molecularly. Despite previous identification of genes expressed in several bipolar cell subtypes, molecules that mark each bipolar cell type still await discovery. In this report, novel genetic markers of murine bipolar cells were found. Candidates were initially generated by using microarray analysis of single bipolar cells and mining of retinal serial analysis of gene expression (SAGE) data. These candidates were subsequently tested for expression in bipolar cells by RNA in situ hybridization. Ten new molecular markers were identified, five of which are highly enriched in their expression in bipolar cells within the adult retina. Double-labeling experiments using probes for previously characterized subsets of bipolar cells were performed to identify the subtypes of bipolar cells that express the novel markers. Additionally, the expression of bipolar cell genes was analyzed in Bhlhb4 knockout retinas, in which rod bipolar cells degenerate postnatally, to delineate further the identity of bipolar cells in which novel markers are found. From the analysis of Bhlhb4 mutant retinas, cone bipolar cell gene expression appears to be relatively unaffected by the degeneration of rod bipolar cells. Identification of molecular markers for the various subtypes of bipolar cells will lead to greater insights into the development and function of these diverse interneurons.
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Affiliation(s)
- Douglas S Kim
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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Mandel S, Spivak-Pohis I, Gozes I. ADNP differential nucleus/cytoplasm localization in neurons suggests multiple roles in neuronal differentiation and maintenance. J Mol Neurosci 2008; 35:127-41. [PMID: 18286385 DOI: 10.1007/s12031-007-9013-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2007] [Accepted: 10/01/2007] [Indexed: 11/26/2022]
Abstract
Complete deficiency in activity-dependent neuroprotective protein (ADNP) results in neural tube closure defects and death at gestation day 9 in mice. ADNP-deficient embryos exhibit dramatic increases in gene transcripts associated with lipid metabolism coupled to reduction in organogenesis/neurogenesis-related transcripts. In the pluripotent teratocarcinoma cell line P19, ADNP was shown to interact with specific chromatin regions in the neurodifferentiated state, which was associated with binding to the heterochromatin protein 1 alpha. In this study, using P19 cells as a differentiation model, we showed that ADNP expression and cytoplasm/nucleus distribution is unique in neuronal-differentiated cells compared to cardiovascular and nondifferentiated pluripotent cells. ADNP-like immunohistochemical localization to the neuronal cytoplasm and neurites was shown in this study not only in the cellular model but also in the brain cerebral cortex and olfactory bulb. Small hairpin RNA ADNP downregulation was used to further investigate ADNP involvement in p19 neurodifferentiation. An approximately 80% robust reduction in ADNP led to a substantial reduction in embryoid body formation and a significant reduction (approximately 50%) in neurite numbers. These results position ADNP in direct association with neuronal cell differentiation and maturation.
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Affiliation(s)
- Shmuel Mandel
- Department of Human Molecular Genetics and Biochemistry, Sackler Medical School, Tel Aviv University, Tel Aviv, 69978, Israel
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A new GFP-tagged line reveals unexpected Otx2 protein localization in retinal photoreceptors. BMC DEVELOPMENTAL BIOLOGY 2007; 7:122. [PMID: 17980036 PMCID: PMC2204009 DOI: 10.1186/1471-213x-7-122] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 11/02/2007] [Indexed: 12/03/2022]
Abstract
Background Dynamic monitoring of protein expression and localization is fundamental to the understanding of biological processes. The paired-class homeodomain-containing transcription factor Otx2 is essential for normal head and brain development in vertebrates. Recent conditional knockout studies have pointed to multiple roles of this protein during late development and post-natal life. Yet, later expression and functions remain poorly characterized as specific reagents to detect the protein at any stage of development are still missing. Results We generated a new mouse line harbouring an insertion of the GFP gene within the Otx2 coding sequence to monitor the gene activity while preserving most of its functions. Our results demonstrate that this line represents a convenient tool to capture the dynamics of Otx2 gene expression from early embryonic stages to adulthood. In addition, we could visualize the intracellular location of Otx2 protein. In the retina, we reinterpret the former view of protein distribution and show a further level of regulation of intranuclear protein localization, which depends on the cell type. Conclusion The GFP-tagged Otx2 mouse line fully recapitulates previously known expression patterns and brings additional accuracy and easiness of detection of Otx2 gene activity. This opens up the way to live imaging of a highly dynamic actor of brain development and can be adapted to any mutant background to probe for genetic interaction between Otx2 and the mutated gene.
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