1
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Liu H, Lu A, Kelley KA, Forrest D. Noncoding Mutations in a Thyroid Hormone Receptor Gene That Impair Cone Photoreceptor Function. Endocrinology 2023; 164:6984996. [PMID: 36631163 PMCID: PMC10091487 DOI: 10.1210/endocr/bqad006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 01/04/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
The function of a hormone receptor requires mechanisms to control precisely where, when, and at what level the receptor gene is expressed. An intriguing case concerns the selective induction of thyroid hormone receptor β2 (TRβ2), encoded by Thrb, in the pituitary and also in cone photoreceptors, in which it critically regulates expression of the opsin photopigments that mediate color vision. Here, we investigate the physiological significance of a candidate enhancer for induction of TRβ2 by mutagenesis of a conserved intron region in its natural context in the endogenous Thrb gene in mice. Mutation of e-box sites for bHLH (basic-helix-loop-helix) transcription factors preferentially impairs TRβ2 expression in cones whereas mutation of nearby sequences preferentially impairs expression in pituitary. A deletion encompassing all sites impairs expression in both tissues, indicating bifunctional activity. In cones, the e-box mutations disrupt chromatin acetylation, blunt the developmental induction of TRβ2, and ultimately impair cone opsin expression and sensitivity to longer wavelengths of light. These results demonstrate the necessity of studying an enhancer in its natural chromosomal context for defining biological relevance and reveal surprisingly critical nuances of level and timing of enhancer function. Our findings illustrate the influence of noncoding sequences over thyroid hormone functions.
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Affiliation(s)
- Hong Liu
- NIDDK, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ailing Lu
- NIDDK, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kevin A Kelley
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Douglas Forrest
- NIDDK, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, MD 20892, USA
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2
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Liao L, Yao Z, Kong J, Zhang X, Li H, Chen W, Xie Q. Transcriptomic analysis reveals the dynamic changes of transcription factors during early development of chicken embryo. BMC Genomics 2022; 23:825. [PMID: 36513979 PMCID: PMC9746114 DOI: 10.1186/s12864-022-09054-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The transition from fertilized egg to embryo in chicken requires activation of hundreds of genes that were mostly inactivated before fertilization, which is accompanied with various biological processes. Undoubtedly, transcription factors (TFs) play important roles in regulating the changes in gene expression pattern observed at early development. However, the contribution of TFs during early embryo development of chicken still remains largely unknown that need to be investigated. Therefore, an understanding of the development of vertebrates would be greatly facilitated by study of the dynamic changes in transcription factors during early chicken embryo. RESULTS In the current study, we selected five early developmental stages in White Leghorn chicken, gallus gallus, for transcriptome analysis, cover 17,478 genes with about 807 million clean reads of RNA-sequencing. We have compared global gene expression patterns of consecutive stages and noted the differences. Comparative analysis of differentially expressed TFs (FDR < 0.05) profiles between neighboring developmental timepoints revealed significantly enriched biological categories associated with differentiation, development and morphogenesis. We also found that Zf-C2H2, Homeobox and bHLH were three dominant transcription factor families that appeared in early embryogenesis. More importantly, a TFs co-expression network was constructed and 16 critical TFs were identified. CONCLUSION Our findings provide a comprehensive regulatory framework of TFs in chicken early embryo, revealing new insights into alterations of chicken embryonic TF expression and broadening better understanding of TF function in chicken embryogenesis.
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Affiliation(s)
- Liqin Liao
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,grid.484195.5Guangdong Provincial Key Lab of Agro Animal Genomics and Molecular Breeding, Guangzhou, 510642 China ,South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou, 510642 P. R. China ,Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 P. R. China
| | - Ziqi Yao
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,grid.484195.5Guangdong Provincial Key Lab of Agro Animal Genomics and Molecular Breeding, Guangzhou, 510642 China
| | - Jie Kong
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,grid.484195.5Guangdong Provincial Key Lab of Agro Animal Genomics and Molecular Breeding, Guangzhou, 510642 China ,South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou, 510642 P. R. China
| | - Xinheng Zhang
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,grid.484195.5Guangdong Provincial Key Lab of Agro Animal Genomics and Molecular Breeding, Guangzhou, 510642 China ,South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou, 510642 P. R. China
| | - Hongxin Li
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,grid.484195.5Guangdong Provincial Key Lab of Agro Animal Genomics and Molecular Breeding, Guangzhou, 510642 China ,Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 P. R. China
| | - Weiguo Chen
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou, 510642 P. R. China
| | - Qingmei Xie
- grid.20561.300000 0000 9546 5767Heyuan Branch, Guangdong Provincial Laboratory of Lingnan Modern Agricultural Science and Technology, College of Animal Science, South China Agricultural University, Guangzhou, 510642 China ,grid.484195.5Guangdong Provincial Key Lab of Agro Animal Genomics and Molecular Breeding, Guangzhou, 510642 China ,South China Collaborative Innovation Center for Poultry Disease Control and Product Safety, Guangzhou, 510642 P. R. China ,Key Laboratory of Animal Health Aquaculture and Environmental Control, Guangzhou, Guangdong 510642 P. R. China
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Olmos-Carreño CL, Figueres-Oñate M, Scicolone GE, López-Mascaraque L. Cell Fate of Retinal Progenitor Cells: In Ovo UbC-StarTrack Analysis. Int J Mol Sci 2022; 23:ijms232012388. [PMID: 36293245 PMCID: PMC9604099 DOI: 10.3390/ijms232012388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/28/2022] Open
Abstract
Clonal cell analysis outlines the ontogenic potential of single progenitor cells, allowing the elucidation of the neural heterogeneity among different cell types and their lineages. In this work, we analyze the potency of retinal stem/progenitor cells through development using the chick embryo as a model. We implemented in ovo the clonal genetic tracing strategy UbC-StarTrack for tracking retinal cell lineages derived from individual progenitors of the ciliary margin at E3.5 (HH21-22). The clonal assignment of the derived-cell progeny was performed in the neural retina at E11.5-12 (HH38) through the identification of sibling cells as cells expressing the same combination of fluorophores. Moreover, cell types were assessed based on their cellular morphology and laminar location. Ciliary margin derived-cell progenies are organized in columnar associations distributed along the peripheral retina with a limited tangential dispersion. The analysis revealed that, at the early stages of development, this region harbors multipotent and committed progenitor cells.
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Affiliation(s)
- Cindy L. Olmos-Carreño
- Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN), CONICET and Departamento de Biología Celular, Histología, Embriología y Genética, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, 28002 Madrid, Spain
| | - María Figueres-Oñate
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, 28002 Madrid, Spain
- Correspondence: (M.F.-O.); (L.L.-M.)
| | - Gabriel E. Scicolone
- Instituto de Biología Celular y Neurociencias “Prof. E. De Robertis” (IBCN), CONICET and Departamento de Biología Celular, Histología, Embriología y Genética, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
| | - Laura López-Mascaraque
- Instituto Cajal-CSIC, Molecular, Cellular and Developmental Neurobiology Department, 28002 Madrid, Spain
- Correspondence: (M.F.-O.); (L.L.-M.)
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4
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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: 3] [Impact Index Per Article: 1.5] [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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5
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Kumamoto T, Ohtaka-Maruyama C. Visualizing Cortical Development and Evolution: A Toolkit Update. Front Neurosci 2022; 16:876406. [PMID: 35495046 PMCID: PMC9039325 DOI: 10.3389/fnins.2022.876406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/17/2022] [Indexed: 11/13/2022] Open
Abstract
Visualizing the process of neural circuit formation during neurogenesis, using genetically modified animals or somatic transgenesis of exogenous plasmids, has become a key to decipher cortical development and evolution. In contrast to the establishment of transgenic animals, the designing and preparation of genes of interest into plasmids are simple and easy, dispensing with time-consuming germline modifications. These advantages have led to neuron labeling based on somatic transgenesis. In particular, mammalian expression plasmid, CRISPR-Cas9, and DNA transposon systems, have become widely used for neuronal visualization and functional analysis related to lineage labeling during cortical development. In this review, we discuss the advantages and limitations of these recently developed techniques.
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Affiliation(s)
- Takuma Kumamoto
- Developmental Neuroscience Project, Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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6
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Sanketi BD, Kurpios NA. In Ovo Gain- and Loss-of-Function Approaches to Study Gut Morphogenesis. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2438:163-181. [PMID: 35147942 DOI: 10.1007/978-1-0716-2035-9_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The polarity of cellular components is essential for cellular shape changes, oriented cell migration, and modulating intra- and intercellular mechanical forces. However, many aspects of polarized cell behavior-especially dynamic cell shape changes during the process of morphogenesis-are almost impossible to study in cells cultured in plastic dishes. Avian embryos have always been a treasured model system to study vertebrate morphogenesis for developmental biologists. Avian embryos recapitulate human biology particularly well in the early stages due to their flat disc gastruloids. Since avian embryos can be manipulated in ovo they present paramount opportunities for highly localized targeting of genetic mechanisms during cellular and developmental processes. Here, we review the application of these methods for both gain of function and loss of function of a gene of interest at a specific developmental stage during left-right (LR) asymmetric gut morphogenesis. These tools present a powerful premise to investigate various polarized cellular activities and molecular processes in vivo in a reproducible manner.
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Affiliation(s)
- Bhargav D Sanketi
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA
| | - Natasza A Kurpios
- Department of Molecular Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY, USA.
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7
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Chen X, Emerson MM. Notch signaling represses cone photoreceptor formation through the regulation of retinal progenitor cell states. Sci Rep 2021; 11:14525. [PMID: 34267251 PMCID: PMC8282820 DOI: 10.1038/s41598-021-93692-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 06/25/2021] [Indexed: 11/29/2022] Open
Abstract
Notch signaling is required to repress the formation of vertebrate cone photoreceptors and to maintain the proliferative potential of multipotent retinal progenitor cells. However, the mechanism by which Notch signaling controls these processes is unknown. Recently, restricted retinal progenitor cells with limited proliferation capacity and that preferentially generate cone photoreceptors have been identified. Thus, there are several potential steps during cone genesis that Notch signaling could act. Here we use cell type specific cis-regulatory elements to localize the primary role of Notch signaling in cone genesis to the formation of restricted retinal progenitor cells from multipotent retinal progenitor cells. Localized inhibition of Notch signaling in restricted progenitor cells does not alter the number of cones derived from these cells. Cell cycle promotion is not a primary effect of Notch signaling but an indirect effect on progenitor cell state transitions that leads to depletion of the multipotent progenitor cell population. Taken together, this suggests that the role of Notch signaling in cone photoreceptor formation and proliferation are both mediated by a localized function of Notch in multipotent retinal progenitor cells to repress the formation of restricted progenitor cells.
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Affiliation(s)
- Xueqing Chen
- Biology PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Mark M Emerson
- Biology PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA.
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA.
- Biochemistry PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA.
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8
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A defined subset of clonal retinal stem cell spheres is biased to RPE differentiation. iScience 2021; 24:102574. [PMID: 34151227 PMCID: PMC8188557 DOI: 10.1016/j.isci.2021.102574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/24/2021] [Accepted: 05/18/2021] [Indexed: 11/19/2022] Open
Abstract
Retinal stem cells (RSCs) are rare pigmented cells found in the pigmented ciliary layer of the mammalian retina. Studies show that RSCs can replicate to maintain the stem cell pool and produce retinal progenitors that differentiate into all retinal cell types. We classified RSCs based on their level and distribution of pigment into heavily pigmented (HP), lightly pigmented (LP), and centrally pigmented (CP) spheres. We report that CP spheres are capable of generating large cobblestone lawns of retinal pigment epithelial (RPE) cells. The other clonal sphere types (HP and LP) primarily produce cells with neural morphology and fewer RPE cells. The RSCs are homogeneous, but their downstream progenitors are different. We found that CP spheres contain highly proliferative populations of early RPE progenitors that respond to proliferative signals from the surrounding non-pigmented cells. HP and LP spheres contain late RPE progenitors which are not affected by proliferative signals. Three types of clonal retinal stem cell spheres form from the same single stem cell Centrally pigmented spheres contain populations of early RPE progenitors Heavily and lightly pigmented spheres contain populations of late RPE progenitors Downstream RPE progenitors are different due to extrinsic and intrinsic factors
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9
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Lonfat N, Wang S, Lee C, Garcia M, Choi J, Park PJ, Cepko C. Cis-regulatory dissection of cone development reveals a broad role for Otx2 and Oc transcription factors. Development 2021; 148:dev198549. [PMID: 33929509 PMCID: PMC8126413 DOI: 10.1242/dev.198549] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/31/2021] [Indexed: 11/20/2022]
Abstract
The vertebrate retina is generated by retinal progenitor cells (RPCs), which produce >100 cell types. Although some RPCs produce many cell types, other RPCs produce restricted types of daughter cells, such as a cone photoreceptor and a horizontal cell (HC). We used genome-wide assays of chromatin structure to compare the profiles of a restricted cone/HC RPC and those of other RPCs in chicks. These data nominated regions of regulatory activity, which were tested in tissue, leading to the identification of many cis-regulatory modules (CRMs) active in cone/HC RPCs and developing cones. Two transcription factors, Otx2 and Oc1, were found to bind to many of these CRMs, including those near genes important for cone development and function, and their binding sites were required for activity. We also found that Otx2 has a predicted autoregulatory CRM. These results suggest that Otx2, Oc1 and possibly other Onecut proteins have a broad role in coordinating cone development and function. The many newly discovered CRMs for cones are potentially useful reagents for gene therapy of cone diseases.
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Affiliation(s)
- Nicolas Lonfat
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Su Wang
- Department of Biomedical Informatics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - ChangHee Lee
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Mauricio Garcia
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Jiho Choi
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Peter J. Park
- Department of Biomedical Informatics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
| | - Connie Cepko
- Department of Genetics, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
- Department of Ophthalmology, Blavatnik Institute; Harvard Medical School, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
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10
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Schick E, Gonzalez KC, Dutta P, Hossain K, Ghinia Tegla MG, Emerson MM. Early cis-regulatory events in the formation of retinal horizontal cells. Dev Biol 2021; 476:88-100. [PMID: 33774011 DOI: 10.1016/j.ydbio.2021.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 11/25/2022]
Abstract
During retinal development, multipotent and restricted progenitor cells generate all of the neuronal cells of the retina. Among these are horizontal cells, which are interneurons that modulate the light-induced signal from photoreceptors. This study utilizes the identification of novel cis-regulatory elements as a method to examine the gene regulatory networks that direct the development of horizontal cells. Here we describe a screen for cis-regulatory elements, or enhancers, for the horizontal cell-associated genes PTF1A, ONECUT1 (OC1), TFAP2A (AP2A), and LHX1. The OC1ECR22 and Tfap2aACR5 elements were shown to be potential enhancers for OC1 and TFAP2A, respectively, and to be specifically active in developing horizontal cells. The OC1ECR22 element is activated by PTF1A and RBPJ, which translates to regulation of OC1 expression and suggests that PTF1A is a direct activator of OC1 expression in developing horizontal cells. The region within the Tfap2aACR5 element that is responsible for its activation was determined to be a 100 bp sequence named Motif 4. Both OC1ECR22 and Tfap2aACR5 are negatively regulated by the nuclear receptors THRB and RXRG, as is the expression of OC1 and AP2A, suggesting that nuclear receptors may have a role in the negative regulation of horizontal cell development.
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Affiliation(s)
- Estie Schick
- Biology PhD Program, Graduate Center, City University of New York, New York, NY, 10016, USA
| | - Kevin C Gonzalez
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Pooja Dutta
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Kazi Hossain
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Miruna G Ghinia Tegla
- Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA
| | - Mark M Emerson
- Biology PhD Program, Graduate Center, City University of New York, New York, NY, 10016, USA; Department of Biology, The City College of New York, City University of New York, New York, NY, 10031, USA; Biochemistry PhD Program, Graduate Center, City University of New York, New York, NY, 10016, USA.
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11
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Direct Readout of Neural Stem Cell Transgenesis with an Integration-Coupled Gene Expression Switch. Neuron 2020; 107:617-630.e6. [PMID: 32559415 PMCID: PMC7447981 DOI: 10.1016/j.neuron.2020.05.038] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 04/22/2020] [Accepted: 05/26/2020] [Indexed: 12/29/2022]
Abstract
Stable genomic integration of exogenous transgenes is essential in neurodevelopmental and stem cell studies. Despite tools driving increasingly efficient genomic insertion with DNA vectors, transgenesis remains fundamentally hindered by the impossibility of distinguishing integrated from episomal transgenes. Here, we introduce an integration-coupled On genetic switch, iOn, which triggers gene expression upon incorporation into the host genome through transposition, thus enabling rapid and accurate identification of integration events following transfection with naked plasmids. In vitro, iOn permits rapid drug-free stable transgenesis of mouse and human pluripotent stem cells with multiple vectors. In vivo, we demonstrate faithful cell lineage tracing, assessment of regulatory elements, and mosaic analysis of gene function in somatic transgenesis experiments that reveal neural progenitor potentialities and interaction. These results establish iOn as a universally applicable strategy to accelerate and simplify genetic engineering in cultured systems and model organisms by conditioning transgene activation to genomic integration. A gene expression switch powered by genomic integration Accelerated readout of additive transgenesis with one or multiple vectors Faithful lineage tracing and mosaic analysis by somatic transfection Near-universal applicability in cultured cells and animal models
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12
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Ghinia Tegla MG, Buenaventura DF, Kim DY, Thakurdin C, Gonzalez KC, Emerson MM. OTX2 represses sister cell fate choices in the developing retina to promote photoreceptor specification. eLife 2020; 9:e54279. [PMID: 32347797 PMCID: PMC7237216 DOI: 10.7554/elife.54279] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 04/28/2020] [Indexed: 12/20/2022] Open
Abstract
During vertebrate retinal development, subsets of progenitor cells generate progeny in a non-stochastic manner, suggesting that these decisions are tightly regulated. However, the gene-regulatory network components that are functionally important in these progenitor cells are largely unknown. Here we identify a functional role for the OTX2 transcription factor in this process. CRISPR/Cas9 gene editing was used to produce somatic mutations of OTX2 in the chick retina and identified similar phenotypes to those observed in human patients. Single cell RNA sequencing was used to determine the functional consequences OTX2 gene editing on the population of cells derived from OTX2-expressing retinal progenitor cells. This confirmed that OTX2 is required for the generation of photoreceptors, but also for repression of specific retinal fates and alternative gene regulatory networks. These include specific subtypes of retinal ganglion and horizontal cells, suggesting that in this context, OTX2 functions to repress sister cell fate choices.
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Affiliation(s)
| | - Diego F Buenaventura
- Department of Biology, The City College of New York, City University of New York (CUNY)New YorkUnited States
- PhD Program in Biology, The Graduate Center of the City University of New York (CUNY)New YorkUnited States
| | - Diana Y Kim
- Department of Biology, The City College of New York, City University of New York (CUNY)New YorkUnited States
| | - Cassandra Thakurdin
- Department of Biology, The City College of New York, City University of New York (CUNY)New YorkUnited States
| | - Kevin C Gonzalez
- Department of Biology, The City College of New York, City University of New York (CUNY)New YorkUnited States
| | - Mark M Emerson
- Department of Biology, The City College of New York, City University of New York (CUNY)New YorkUnited States
- PhD Program in Biology, The Graduate Center of the City University of New York (CUNY)New YorkUnited States
- PhD Program in Biochemistry, The Graduate Center of the City University of New York (CUNY)New YorkUnited States
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Patoori S, Jean-Charles N, Gopal A, Sulaiman S, Gopal S, Wang B, Souferi B, Emerson MM. Cis-regulatory analysis of Onecut1 expression in fate-restricted retinal progenitor cells. Neural Dev 2020; 15:5. [PMID: 32192535 PMCID: PMC7082998 DOI: 10.1186/s13064-020-00142-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/27/2020] [Indexed: 01/03/2023] Open
Abstract
Background The vertebrate retina consists of six major classes of neuronal cells. During development, these cells are generated from a pool of multipotent retinal progenitor cells (RPCs) that express the gene Vsx2. Fate-restricted RPCs have recently been identified, with limited mitotic potential and cell fate possibilities compared to multipotent RPCs. One population of fate-restricted RPCs, marked by activity of the regulatory element ThrbCRM1, gives rise to both cone photoreceptors and horizontal cells. These cells do not express Vsx2, but co-express the transcription factors (TFs) Onecut1 and Otx2, which bind to ThrbCRM1. The components of the gene regulatory networks that control the transition from multipotent to fate-restricted gene expression are not known. This work aims to identify and evaluate cis-regulatory elements proximal to Onecut1 to identify the gene regulatory networks involved in RPC fate-restriction. Method We identified regulatory elements through ATAC-seq and conservation, followed by reporter assays to screen for activity based on temporal and spatial criteria. The regulatory elements of interest were subject to deletion and mutation analysis to identify functional sequences and evaluated by quantitative flow cytometry assays. Finally, we combined the enhancer::reporter assays with candidate TF overexpression to evaluate the relationship between the TFs, the enhancers, and early vertebrate retinal development. Statistical tests included ANOVA, Kruskal-Wallis, or unpaired t-tests. Results Two regulatory elements, ECR9 and ECR65, were identified to be active in ThrbCRM1(+) restricted RPCs. Candidate bHLH binding sites were identified as critical sequences in both elements. Overexpression of candidate bHLH TFs revealed specific enhancer-bHLH interactions. Nhlh1 overexpression expanded ECR65 activity into the Vsx2(+) RPC population, and overexpression of NeuroD1/NeuroG2/NeuroD4 had a similar effect on ECR9. Furthermore, bHLHs that were able to activate ectopic ECR9 reporter were able to induce endogenous Otx2 expression. Conclusions This work reports a large-scale screen to identify spatiotemporally specific regulatory elements near the Onecut1 locus. These elements were used to identify distinct populations in the developing retina. In addition, fate-restricted regulatory elements responded differentially to bHLH factors, and suggest a role for retinal bHLHs upstream of the Otx2 and Onecut1 genes during the formation of restricted RPCs from multipotent RPCs.
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Affiliation(s)
- Sruti Patoori
- Biology PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA.,Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Nathalie Jean-Charles
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Ariana Gopal
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Sacha Sulaiman
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Sneha Gopal
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA.,Present Address: Doctoral program in Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Brian Wang
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA
| | - Benjamin Souferi
- Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA.,Present Address: Touro College of Osteopathic Medicine, New York, NY, 10027, USA
| | - Mark M Emerson
- Biology PhD Program, The Graduate Center, The City University of New York, New York, NY, 10016, USA. .,Department of Biology, The City College of New York, The City University of New York, New York, NY, 10031, USA. .,Biochemistry PhD Program, Graduate Center, City University of New York, New York, NY, 10016, USA.
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Quinn PM, Wijnholds J. Retinogenesis of the Human Fetal Retina: An Apical Polarity Perspective. Genes (Basel) 2019; 10:E987. [PMID: 31795518 PMCID: PMC6947654 DOI: 10.3390/genes10120987] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/20/2022] Open
Abstract
The Crumbs complex has prominent roles in the control of apical cell polarity, in the coupling of cell density sensing to downstream cell signaling pathways, and in regulating junctional structures and cell adhesion. The Crumbs complex acts as a conductor orchestrating multiple downstream signaling pathways in epithelial and neuronal tissue development. These pathways lead to the regulation of cell size, cell fate, cell self-renewal, proliferation, differentiation, migration, mitosis, and apoptosis. In retinogenesis, these are all pivotal processes with important roles for the Crumbs complex to maintain proper spatiotemporal cell processes. Loss of Crumbs function in the retina results in loss of the stratified appearance resulting in retinal degeneration and loss of visual function. In this review, we begin by discussing the physiology of vision. We continue by outlining the processes of retinogenesis and how well this is recapitulated between the human fetal retina and human embryonic stem cell (ESC) or induced pluripotent stem cell (iPSC)-derived retinal organoids. Additionally, we discuss the functionality of in utero and preterm human fetal retina and the current level of functionality as detected in human stem cell-derived organoids. We discuss the roles of apical-basal cell polarity in retinogenesis with a focus on Leber congenital amaurosis which leads to blindness shortly after birth. Finally, we discuss Crumbs homolog (CRB)-based gene augmentation.
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Affiliation(s)
- Peter M.J. Quinn
- Department of Ophthalmology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands;
| | - Jan Wijnholds
- Department of Ophthalmology, Leiden University Medical Center, 2300 RC Leiden, The Netherlands;
- The Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, 1105 BA Amsterdam, The Netherlands
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