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Goes CP, Botezelli VS, De La Cruz SM, Cruz MC, Azambuja AP, Simoes-Costa M, Yan CYI. ASCL1 promotes Scrt2 expression in the neural tube. Front Cell Dev Biol 2024; 12:1324584. [PMID: 38655067 PMCID: PMC11036302 DOI: 10.3389/fcell.2024.1324584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 03/05/2024] [Indexed: 04/26/2024] Open
Abstract
ASCL1 is a transcription factor that directs neural progenitors towards lineage differentiation. Although many of the molecular mechanisms underlying its action have been described, several of its targets remain unidentified. We identified in the chick genome a putative enhancer (cE1) upstream of the transcription factor Scratch2 (Scrt2) locus with a predicted heterodimerization motif for ASCL1 and POU3F2. In this study, we investigated the role of ASCL1 and this enhancer in regulating the expression of the Scrt2 in the embryonic spinal cord. We confirmed that cE1 region interacted with the Scrt2 promoter. cE1 was sufficient to mediate ASCL1-driven expression in the neural tube through the heterodimerization sites. Moreover, Scrt2 expression was inhibited when we removed cE1 from the genome. These findings strongly indicate that ASCL1 regulates Scrt2 transcription in the neural tube through cE1.
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Affiliation(s)
- Carolina Purcell Goes
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Vitória Samartin Botezelli
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Shirley Mirna De La Cruz
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
- Facultad de Ciencias de la Salud, Universidad Científica del Sur, Lima, Peru
| | - Mário Costa Cruz
- Core Research Facilities (CEFAP), Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Ana Paula Azambuja
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, United States
- Department of Systems Biology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Marcos Simoes-Costa
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, United States
- Department of Systems Biology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Chao Yun Irene Yan
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
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England SJ, Rusnock AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular analyses of zebrafish V0v spinal interneurons and identification of transcriptional regulators downstream of Evx1 and Evx2 in these cells. Neural Dev 2023; 18:8. [PMID: 38017520 PMCID: PMC10683209 DOI: 10.1186/s13064-023-00176-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/12/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. METHODS To identify candidate members of V0v gene regulatory networks, we FAC-sorted wild-type and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. RESULTS Our data reveal two molecularly distinct subtypes of zebrafish V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuron expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. CONCLUSIONS This study identifies two molecularly distinct subsets of zebrafish V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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Affiliation(s)
| | | | - Amra Mujcic
- Biology Department, Syracuse University, Syracuse, NY, USA
| | | | - Sarah de Jager
- Physiology, Development and Neuroscience Department, Cambridge University, Cambridge, UK
| | | | - José L Juárez-Morales
- Biology Department, Syracuse University, Syracuse, NY, USA
- Programa de IxM-CONAHCYT, Centro de Investigaciones Biológicas del Noroeste, S.C. (CIBNOR), La Paz, Baja California Sur, México
| | | | - Ginny Grieb
- Biology Department, Syracuse University, Syracuse, NY, USA
| | - Santanu Banerjee
- Biological Sciences Department, SUNY-Cortland, Cortland, NY, USA
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3
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England SJ, Woodard AK, Mujcic A, Kowalchuk A, de Jager S, Hilinski WC, Juárez-Morales JL, Smith ME, Grieb G, Banerjee S, Lewis KE. Molecular Analyses of V0v Spinal Interneurons and Identification of Transcriptional Regulators Downstream of Evx1 and Evx2 in these Cells. RESEARCH SQUARE 2023:rs.3.rs-3290462. [PMID: 37693471 PMCID: PMC10491344 DOI: 10.21203/rs.3.rs-3290462/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Background V0v spinal interneurons are highly conserved, glutamatergic, commissural neurons that function in locomotor circuits. We have previously shown that Evx1 and Evx2 are required to specify the neurotransmitter phenotype of these cells. However, we still know very little about the gene regulatory networks that act downstream of these transcription factors in V0v cells. Methods To identify candidate members of V0v gene regulatory networks, we FAC-sorted WT and evx1;evx2 double mutant zebrafish V0v spinal interneurons and expression-profiled them using microarrays and single cell RNA-seq. We also used in situ hybridization to compare expression of a subset of candidate genes in evx1;evx2 double mutants and wild-type siblings. Results Our data reveal two molecularly distinct subtypes of V0v spinal interneurons at 48 h and suggest that, by this stage of development, evx1;evx2 double mutant cells transfate into either inhibitory spinal interneurons, or motoneurons. Our results also identify 25 transcriptional regulator genes that require Evx1/2 for their expression in V0v interneurons, plus a further 11 transcriptional regulator genes that are repressed in V0v interneurons by Evx1/2. Two of the latter genes are hmx2 and hmx3a. Intriguingly, we show that Hmx2/3a, repress dI2 interneuronal expression of skor1a and nefma, two genes that require Evx1/2 for their expression in V0v interneurons. This suggests that Evx1/2 might regulate skor1a and nefma expression in V0v interneurons by repressing Hmx2/3a expression. Conclusions This study identifies two molecularly distinct subsets of V0v spinal interneurons, as well as multiple transcriptional regulators that are strong candidates for acting downstream of Evx1/2 to specify the essential functional characteristics of these cells. Our data further suggest that in the absence of both Evx1 and Evx2, V0v spinal interneurons initially change their neurotransmitter phenotypes from excitatory to inhibitory and then, later, start to express markers of distinct types of inhibitory spinal interneurons, or motoneurons. Taken together, our findings significantly increase our knowledge of V0v and spinal development and move us closer towards the essential goal of identifying the complete gene regulatory networks that specify this crucial cell type.
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Xu Y, Zhao H, Wang Z, Gao H, Liu J, Li K, Song Z, Yuan C, Lan X, Pan C, Zhang S. Developmental exposure to environmental levels of cadmium induces neurotoxicity and activates microglia in zebrafish larvae: From the perspectives of neurobehavior and neuroimaging. CHEMOSPHERE 2022; 291:132802. [PMID: 34752834 DOI: 10.1016/j.chemosphere.2021.132802] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/15/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Cadmium (Cd) is a worldwide environmental pollutant that postures serious threats to humans and ecosystems. Over the years, its adverse effects on the central nervous system (CNS) have been concerned, whereas the underlying cellular/molecular mechanisms remain unclear. In this study, taking advantages of zebrafish model in high-throughput imaging and behavioral tests, we have explored the potential developmental neurotoxicity of Cd at environmentally relevant levels, from the perspectives of neurobehavior and neuroimaging. Briefly, Cd2+ exposure resulted in a general impairment of zebrafish early development. Zebrafish neurobehavioral patterns including locomotion and reactivity to environmental signals were significantly perturbed upon Cd2+ exposure. Importantly, a combination of in vivo two-photon neuroimaging, flow cytometry and gene expression analyses revealed notable neurodevelopmental disorders as well as neuroimmune responses induced by Cd2+ exposure. Both cell-cycle arrest and apoptosis contributed jointly to a significant decrease of neuronal density in zebrafish larvae exposed to Cd2+. The dramatic morphological alterations of microglia from multi-branched to amoeboid, the microgliosis, as well as the modulation of gene expression profiles demonstrated a strong activation of microglia and neuroinflammation triggered by environmental levels of Cd2+. Together, our study points to the developmental toxicity of Cd in inducing CNS impairment and neuroinflammation thereby providing visualized etiological evidence of this heavy metal induced neurodevelopmental disorders. It's tempting to speculate that this research model might represent a promising tool not only for understanding the molecular mechanisms of Cd-induced neurotoxicity, but also for developing pharmacotherapies to mitigate the neurological damage resulting from exposure to Cd, and other neurotoxicants.
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Affiliation(s)
- Yanyi Xu
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Haiyu Zhao
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China.
| | - Zuo Wang
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Hao Gao
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Junru Liu
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Kemin Li
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Zan Song
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Cong Yuan
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China
| | - Xianyong Lan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi Province, China
| | - Chuanying Pan
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, 712100, Shaanxi Province, China
| | - Shengxiang Zhang
- School of Life Sciences, Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, Lanzhou University, No. 222 South Tianshui Road, Lanzhou, 730000, Gansu Province, China.
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Yu J, Xiong C, Zhuo B, Wen Z, Shen J, Liu C, Chang L, Wang K, Wang M, Wu C, Wu X, Xu X, Ruan H, Li G. Analysis of Local Chromatin States Reveals Gene Transcription Potential during Mouse Neural Progenitor Cell Differentiation. Cell Rep 2021; 32:107953. [PMID: 32726618 DOI: 10.1016/j.celrep.2020.107953] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/25/2020] [Accepted: 07/02/2020] [Indexed: 01/23/2023] Open
Abstract
Chromatin dynamics play a critical role in cell fate determination and maintenance by regulating the expression of genes essential for development and differentiation. In mouse embryonic stem cells (mESCs), maintenance of pluripotency coincides with a poised chromatin state containing active and repressive histone modifications. However, the structural features of poised chromatin are largely uncharacterized. By adopting mild time-course MNase-seq with computational analysis, the low-compact chromatin in mESCs is featured in two groups: one in more open regions, corresponding to an active state, and the other enriched with bivalent histone modifications, considered the poised state. A parameter called the chromatin opening potential index (COPI) is also devised to quantify the transcription potential based on the dynamic changes of MNase-seq signals at promoter regions. Use of COPI provides effective prediction of gene activation potential and, more importantly, reveals a few developmental factors essential for mouse neural progenitor cell (NPC) differentiation.
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Affiliation(s)
- Juan Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Chaoyang Xiong
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Baowen Zhuo
- Baoan Maternal and Child Health Hospital, Jinan University, Shenzhen 518102, China
| | - Zengqi Wen
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jie Shen
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Cuifang Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Luyuan Chang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Kehui Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Min Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Chenyi Wu
- Molecular Biophysics Laboratories, School of Biological Sciences, University of Portsmouth, Portsmouth PO1 2DY, UK
| | - Xudong Wu
- Department of Cell Biology, Tianjin Medical University, Qixiangtai Road 22, Tianjin 300070, China
| | - Xueqing Xu
- Baoan Maternal and Child Health Hospital, Jinan University, Shenzhen 518102, China.
| | - Haihe Ruan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Guohong Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
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Goes CP, Vieceli FM, De La Cruz SM, Simões-Costa M, Yan CYI. Scratch2, a Snail Superfamily Member, Is Regulated by miR-125b. Front Cell Dev Biol 2020; 8:769. [PMID: 32984310 PMCID: PMC7477046 DOI: 10.3389/fcell.2020.00769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 07/21/2020] [Indexed: 12/16/2022] Open
Abstract
Scratch2 is a transcription factor expressed in a very restricted population of vertebrate embryonic neural cell precursors involved in their survival, differentiation, and migration. The mechanisms that control its expression remain unknown and could contribute towards our understanding of gene regulation during neural differentiation and evolution. Here we investigate the role of microRNAs (miRNAs) in the Scrt2 post-transcriptional regulatory mechanism. We identified binding sites for miR-125b and -200b in the Scrt2 3′UTR in silico. We confirmed the repressive-mediated activity of the Scrt2 3′UTR through electroporation of luciferase constructs into chick embryos. Further, both CRISPR/Cas9-mediated deletion of miR-125b/-200b responsive elements from chicken Scrt2 3′UTR and expression of miRNAs sponges increased Scrt2 expression field, suggesting a role for these miRNAs as post-transcriptional regulators of Scrt2. The biological effect of miR-125b titration was much more pronounced than that of miR-200b. Therefore, we propose that, after transcription, miR-125b fine-tunes the Scrt2 expression domain.
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Affiliation(s)
- Carolina Purcell Goes
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.,Department of Molecular Biology and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | - Felipe Monteleone Vieceli
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Shirley Mirna De La Cruz
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Marcos Simões-Costa
- Department of Molecular Biology and Genetics, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY, United States
| | - Chao Yun Irene Yan
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Wu TS, Cheng YC, Chen PJ, Huang YT, Yu FY, Liu BH. Exposure to aflatoxin B 1 interferes with locomotion and neural development in zebrafish embryos and larvae. CHEMOSPHERE 2019; 217:905-913. [PMID: 30466059 DOI: 10.1016/j.chemosphere.2018.11.058] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 05/19/2023]
Abstract
Aflatoxin B1 (AFB1) is the major mycotoxin that contaminates aquafeeds and regarded as a causative agent in illnesses and the mortality of aquacultural species. However, the effects of AFB1 on developing fish and associated toxic mechanism are still unknown. This study examines the behavioral changes, neuronal morphology and gene expression in zebrafish embryos and larvae upon exposure to aflatoxin solutions. Treatment of 6 h post fertilization (hpf) embryos with AFB1 at 15-75 ng/mL significantly changed the swimming patterns of seven days post-fertilization (dpf) zebrafish larvae. Larvae in the 15 ng/mL group demonstrated a hypolocomotor activity in free swimming, but hyperlocomotion was observed in the larvae exposed to 30-75 ng/mL AFB1. AFB1 at 75 ng/mL also significantly reduced the startle response of 7 dpf larvae after tapping stimulus. Exposure to AFB1 resulted in an aberrant morphology of trigeminal ganglion and hindbrain neurons in transgenic embryos (HuC:eGFP); this finding was supported by acetylated alpha-tubulin staining in wild-type fish. Additionally, AFB1 altered the levels of neurotoxic markers, including gfap and huC. The transcriptomic profile of AFB1-treated embryos revealed several differentially expressed genes that are related to neuroactivity and neurogenesis. PCR analysis verified that AFB1 significantly down-regulated the expression of ngfa and atp1b1b genes and increased that of prtga gene. The results herein indicate the toxicological impacts of AFB1 on the behaviors and neurodevelopment of fish in the early embryonic stage. Disruption of neural formation and synapse dysfunction may be responsible for the behavioral alteration.
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Affiliation(s)
- Ting-Shuan Wu
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ya-Chih Cheng
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Pei-Jen Chen
- Department of Agricultural Chemistry, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
| | - Ying-Tzu Huang
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Feng-Yih Yu
- Department of Biomedical Sciences, Chung Shan Medical University, Taiwan; Department of Medical Research, Chung Shan Medical University Hospital, Taichung, Taiwan.
| | - Biing-Hui Liu
- Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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Paul V, Tonchev AB, Henningfeld KA, Pavlakis E, Rust B, Pieler T, Stoykova A. Scratch2 modulates neurogenesis and cell migration through antagonism of bHLH proteins in the developing neocortex. ACTA ACUST UNITED AC 2012. [PMID: 23180754 DOI: 10.1093/cercor/bhs356] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Scratch genes (Scrt) are neural-specific zinc-finger transcription factors (TFs) with an unknown function in the developing brain. Here, we show that, in addition to the reported expression of mammalian Scrt2 in postmitotic differentiating and mature neurons in the developing and early postnatal brain, Scrt2 is also localized in subsets of mitotic and neurogenic radial glial (RGP) and intermediate (IP) progenitors, as well as in their descendants-postmitotic IPs and differentiating neurons at the border subventricular/intermediate zone. Conditional activation of transgenic Scrt2 in cortical progenitors in mice promotes neuronal differentiation by favoring the direct mode of neurogenesis of RGPs at the onset of neurogenesis, at the expense of IP generation. Neuronal amplification via indirect IP neurogenesis is thereby extenuated, leading to a mild postnatal reduction of cortical thickness. Forced in vivo overexpression of Scrt2 suppressed the generation of IPs from RGPs and caused a delay in the radial migration of upper layer neurons toward the cortical plate. Mechanistically, our results indicate that Scrt2 negatively regulates the transcriptional activation of the basic helix loop helix TFs Ngn2/NeuroD1 on E-box containing common target genes, including Rnd2, a well-known major effector for migrational defects in developing cortex. Altogether, these findings reveal a modulatory role of Scrt2 protein in cortical neurogenesis and neuronal migration.
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Affiliation(s)
- Vanessa Paul
- Research Group Molecular Developmental Neurobiology, Max-Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
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Jung SH, Kim HS, Ryu JH, Gwak JW, Bae YK, Kim CH, Yeo SY. Her4-positive population in the tectum opticum is proliferating neural precursors in the adult zebrafish brain. Mol Cells 2012; 33:627-32. [PMID: 22570150 PMCID: PMC3887756 DOI: 10.1007/s10059-012-0091-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Accepted: 04/04/2012] [Indexed: 11/25/2022] Open
Abstract
Previous studies have shown that Notch signaling not only regulates the number of early differentiating neurons, but also maintains proliferating neural precursors in the neural tube. Although it is well known that Notch signaling is closely related to the differentiation of adult neural stem cells, none of transgenic zebrafish provides a tool to figure out the relationship between Notch signaling and the differentiation of neural precursors. The goal of this study was to characterize Her4-positive cells by comparing the expression of a fluorescent Her4 reporter in Tg[her4-dRFP] animals with a GFAP reporter in Tg[gfap-GFP] adult zebrafish. BrdU incorporation indicated that dRFP-positive cells were proliferating and a double labeling assay revealed that a significant fraction of the Her4-dRFP positive population was also GFAP-GFP positive. Our observations suggest that a reporter line with Notch-dependent gene expression can provide a tool to examine proliferating neural precursors and/or neuronal/glial precursors in the development of the adult nervous system to examine the model in which Notch signaling maintains proliferating neural precursors in the neural tube.
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Affiliation(s)
- Seung-Hyun Jung
- Department of Biology and GRAST, Chungnam National University, Daejeon 305-764,
Korea
| | - Hyung-Seok Kim
- Department of Genetic Engineering, Kyungpook National University, Daegu 702-701,
Korea
| | - Jae-Ho Ryu
- Department of Biology and GRAST, Chungnam National University, Daejeon 305-764,
Korea
| | - Jung-Woo Gwak
- Department of Biotechnology, Division of Applied Chemistry and Biotechnology, Hanbat National University, Daejeon 305-719,
Korea
| | - Young-Ki Bae
- Research Institute, National Cancer Center, Goyang 410-769,
Korea
| | - Cheol-Hee Kim
- Department of Biology and GRAST, Chungnam National University, Daejeon 305-764,
Korea
| | - Sang-Yeob Yeo
- Department of Biotechnology, Division of Applied Chemistry and Biotechnology, Hanbat National University, Daejeon 305-719,
Korea
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