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Martinez De La Cruz B, Markus R, Malla S, Haig MI, Gell C, Sang F, Bellows E, Sherif MA, McLean D, Lourdusamy A, Self T, Bodi Z, Smith S, Fay M, Macdonald IA, Fray R, Knight HM. Modifying the m 6A brain methylome by ALKBH5-mediated demethylation: a new contender for synaptic tagging. Mol Psychiatry 2021; 26:7141-7153. [PMID: 34663904 PMCID: PMC8872986 DOI: 10.1038/s41380-021-01282-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/02/2021] [Accepted: 08/25/2021] [Indexed: 02/08/2023]
Abstract
Synaptic plasticity processes, which underlie learning and memory formation, require RNA to be translated local to synapses. The synaptic tagging hypothesis has previously been proposed to explain how mRNAs are available at specific activated synapses. However how RNA is regulated, and which transcripts are silenced or processed as part of the tagging process is still unknown. Modification of RNA by N6-methyladenosine (m6A/m) influences the cellular fate of mRNA. Here, by advanced microscopy, we showed that m6A demethylation by the eraser protein ALKBH5 occurs at active synaptic ribosomes and at synapses during short term plasticity. We demonstrated that at activated glutamatergic post-synaptic sites, both the YTHDF1 and YTHDF3 reader and the ALKBH5 eraser proteins increase in co-localisation to m6A-modified RNAs; but only the readers showed high co-localisation to modified RNAs during late-stage plasticity. The YTHDF1 and YTHFDF3 readers also exhibited differential roles during synaptic maturation suggesting that temporal and subcellular abundance may determine specific function. m6A-sequencing of human parahippocampus brain tissue revealed distinct white and grey matter m6A methylome profiles indicating that cellular context is a fundamental factor dictating regulated pathways. However, in both neuronal and glial cell-rich tissue, m6A effector proteins are themselves modified and m6A epitranscriptional and posttranslational modification processes coregulate protein cascades. We hypothesise that the availability m6A effector protein machinery in conjunction with RNA modification, may be important in the formation of condensed synaptic nanodomain assemblies through liquid-liquid phase separation. Our findings support that m6A demethylation by ALKBH5 is an intrinsic component of the synaptic tagging hypothesis and a molecular switch which leads to alterations in the RNA methylome, synaptic dysfunction and potentially reversible disease states.
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Affiliation(s)
- Braulio Martinez De La Cruz
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK ,grid.415971.f0000 0004 0605 8588Present Address: MRC Laboratory of Molecular Cell Biology, UCL, London, UK
| | - Robert Markus
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Sunir Malla
- grid.4563.40000 0004 1936 8868Deep Seq: Next Generation Sequencing Facility, University of Nottingham, Nottingham, UK
| | - Maria Isabel Haig
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Chris Gell
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Fei Sang
- grid.4563.40000 0004 1936 8868Deep Seq: Next Generation Sequencing Facility, University of Nottingham, Nottingham, UK
| | - Eleanor Bellows
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Mahmoud Awad Sherif
- grid.4563.40000 0004 1936 8868Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Denise McLean
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Anbarasu Lourdusamy
- grid.4563.40000 0004 1936 8868Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Tim Self
- grid.4563.40000 0004 1936 8868School of Life Sciences Imaging Facility, University of Nottingham, Nottingham, UK
| | - Zsuzsanna Bodi
- grid.4563.40000 0004 1936 8868Division of Plant Sciences, School of Biosciences, University of Nottingham, Nottingham, UK
| | - Stuart Smith
- grid.4563.40000 0004 1936 8868Children’s Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Michael Fay
- grid.4563.40000 0004 1936 8868Nanoscale and Microscale Research Centre, University of Nottingham, Nottingham, UK
| | - Ian A. Macdonald
- grid.4563.40000 0004 1936 8868Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Rupert Fray
- grid.4563.40000 0004 1936 8868Division of Plant Sciences, School of Biosciences, University of Nottingham, Nottingham, UK
| | - Helen Miranda Knight
- Division of Cells, Organisms and Molecular Genetics, School of Life Sciences, University of Nottingham, Nottingham, UK.
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Abe T, Kanemitu Y, Nakasone M, Kawahata I, Yamakuni T, Nakajima A, Suzuki N, Nishikawa M, Hishinuma T, Tomioka Y. SLC10A4 is a protease-activated transporter that transports bile acids. J Biochem 2013; 154:93-101. [DOI: 10.1093/jb/mvt031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Tian D, Litvak V, Toledo-Rodriguez M, Carmon S, Lev S. Nir2, a novel regulator of cell morphogenesis. Mol Cell Biol 2002; 22:2650-62. [PMID: 11909959 PMCID: PMC133726 DOI: 10.1128/mcb.22.8.2650-2662.2002] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cell morphogenesis requires dynamic reorganization of the actin cytoskeleton, a process that is tightly regulated by the Rho family of small GTPases. These GTPases act as molecular switches by shuttling between their inactive GDP-bound and active GTP-bound forms. Here we show that Nir2, a novel protein related to Drosophila retinal degeneration B (RdgB), markedly affects cell morphology through a novel Rho-inhibitory domain (Rid) which resides in its N-terminal region. Rid exhibits sequence homology with the Rho-binding site of formin-homology (FH) proteins and leads to an apparent loss of F-actin staining when ectopically expressed in mammalian cells. We also show that Rid inhibits Rho-mediated stress fiber formation and lysophosphatidic acid-induced RhoA activation. Biochemical studies demonstrated that Nir2, via Rid, preferentially binds to the inactive GDP-bound form of the small GTPase Rho. Microinjection of antibodies against Nir2 into neuronal cells markedly attenuates neurite extension, whereas overexpression of Nir2 in these cells attenuates Rho-mediated neurite retraction. These results implicate Nir2 as a novel regulator of the small GTPase Rho in actin cytoskeleton reorganization and cell morphogenesis.
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Affiliation(s)
- Donghua Tian
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
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Chen A, Laskar-Levy O, Ben-Aroya N, Koch Y. Transcriptional regulation of the human GnRH II gene is mediated by a putative cAMP response element. Endocrinology 2001; 142:3483-92. [PMID: 11459794 DOI: 10.1210/endo.142.8.8302] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Human neuronal medulloblastoma cells (TE-671) were recently demonstrated to express the two forms of GnRH (GnRH-I and GnRH-II). We have used this cell line as a model system to demonstrate regulation of the human GnRH-II gene by cAMP. RT-PCR and Southern hybridization demonstrated that GnRH-II mRNA is strongly up-regulated ( approximately 6-fold) by (Bu)(2)cAMP. The concentration of GnRH-II that was released into the medium of TE-671 cells treated with the cAMP analog was significantly higher than that of the untreated cells. TE-671 cells that were stimulated by (Bu)(2)cAMP demonstrated morphological changes and strong immunoreactive GnRH-II staining in part of the cell population. After screening of the GnRH-II promoter sequence, we identified a putative cAMP response element consensus site. The GnRH-I and GnRH-II promoters were isolated by PCR using human genomic DNA and cloned into the luciferase reporter plasmid. By measuring the basal activity of the promoters that were transfected to TE-671 cells, we found a much stronger basal activity of the GnRH-II promoter compared with that of GnRH-I. Treatment of transfected TE-671 cells with (Bu)(2)cAMP resulted in a strong activation of the GnRH-II promoter compared with a modest activation of the GnRH-I promoter. To determine the functionality of this putative cAMP response element site, we mutated this site. TE-671 cells that were transfected with cAMP response element mutant constructs demonstrated a diminished basal activity of the GnRH-II promoter. Treatment of the transfected cells with the cAMP analog demonstrated a decrease to 0.03% of the activity of the mutated promoter compared with that of the wild type. These results clearly demonstrate the importance of the putative cAMP response element site for the basal activity as well as for induction of the GnRH-II promoter by cAMP.
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Affiliation(s)
- A Chen
- Department of Neurobiology, Weizmann Institute of Science, Rehovot 76100, Israel
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Levavi-Sivan B, Park BH, Fuchs S, Fishburn CS. Human D3 dopamine receptor in the medulloblastoma TE671 cell line: cross-talk between D1 and D3 receptors. FEBS Lett 1998; 439:138-42. [PMID: 9849894 DOI: 10.1016/s0014-5793(98)01356-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In search of a cell line in which the D3 dopamine receptor is expressed endogenously, we found that the neuron-derived human medulloblastoma cell line TE671 expresses the human D3 (hD3) and D1 (hD1) receptor, but neither the D2 or D4 receptors. Exposure of TE671 cells to the D3 agonist 7-OH-DPAT (DPAT), or to the D1 agonist SKF-38393 (SKF) increased the expression of hD3 or hD1 mRNA, respectively. Moreover, whereas DPAT had no effect on hD1 mRNA levels, stimulating the cells with SKF caused an increase in both hD1 and hD3 transcript levels. These results suggest (i) that following ligand stimulation, hD3 and hD1 receptors are upregulated to enhance their own receptor expression, and (ii) that upregulation of hD1 receptor transcripts leads to a stimulation of the hD3 dopamine receptor transcripts.
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Affiliation(s)
- B Levavi-Sivan
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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Paulson HL, Das SS, Crino PB, Perez MK, Patel SC, Gotsdiner D, Fischbeck KH, Pittman RN. Machado-Joseph disease gene product is a cytoplasmic protein widely expressed in brain. Ann Neurol 1997; 41:453-62. [PMID: 9124802 DOI: 10.1002/ana.410410408] [Citation(s) in RCA: 207] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Machado-Joseph disease (MJD) is one of at least six neurodegenerative diseases caused by expansion of a CAG repeat encoding a polyglutamine tract in the disease protein. To study the molecular mechanism of disease, we isolated both normal and expanded repeat MJD1 cDNAs, and generated antiserum against the recombinant gene product, called ataxin-3. Using this antiserum, we demonstrate that in disease tissue, both the normal and mutant ataxin-3 protein are expressed throughout the body and in all regions of the brain examined, including areas generally spared by disease. In brain, certain regions (the striatum, for example) express ataxin-3 in only a limited subset of neurons. Immunolocalization studies in normal and disease brain, and in transfected cells, indicate that ataxin-3 is predominantly a cytoplasmic protein that localizes to neuronal processes as well. We conclude that in MJD, as in other polyglutamine repeat diseases, cellular expression of the disease gene is not itself sufficient to cause neuronal degeneration; other cell-specific factors must be invoked to explain the restricted neuropathology seen in MJD. The restricted expression of ataxin-3 in certain regions, however, may influence the pattern of neurodegeneration and provide clues to the protein's function.
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Affiliation(s)
- H L Paulson
- Department of Pharmacology, University of Pennsylvania, Philadelphia 19104, USA
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Abstract
In our studies we explored the functional relevance of nAChR diversity, in part from the perspective of nAChR as ideal targets for regulatory influences, including those mediated via actions of ligands at other "interacting" receptors. We explored possible mechanisms for nAChR regulation and roles played by nAChR subtype and subunit diversity in those processes. We showed that regulatory factors can influence nAChR numbers at transcriptional and posttranscriptional levels and can affect nAChR function and subcellular distribution. We also demonstrated that nAChR expression can be influenced (1) by nicotinic ligands, (2) by second messengers, (3) by growth factors, (4) by agents targeting the nucleus, and (5) by agents targeting the cytoskeleton. We found common effects of some regulatory influences on more than one nAChR subtype, and we found instances where regulatory influences differ for different cell and nAChR types. Even from the very limited number of these initial studies, it is evident that nAChR subunit and subtype diversity, which alone can provide diversity in nAChR functions, localization, and ligand sensitivity, dovetails with diversity in cellular signaling mechanisms that can affect nAChR expression to amplify the potential functional plasticity of cholinoceptive cells. As examples, we discussed potential roles for nAChR diversity and regulatory plasticity in synapse remodeling and in changes in neuronal circuit conditions. These examples illustrate how nAChR diversity could play important roles in the regulation of nervous system function.
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Affiliation(s)
- R J Lukas
- Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013, USA
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Affiliation(s)
- D N Levy
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia 19104, USA
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Dufay N, Belin MF, Confavreux C, Touraine-Moulin F, Derrington EA. Cholera toxin beta subunit induces the differentiation of human medulloblastoma cell line DEV in a neuronal pathway. Eur J Neurosci 1994; 6:1633-40. [PMID: 7850027 DOI: 10.1111/j.1460-9568.1994.tb00554.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Medulloblastomas are primitive neuroectodermal tumours that are thought to arise from multipotent precursor cells in the cerebellum. Medulloblastoma cells may be undifferentiated or exhibit glial, neuronal or ependymal characteristics, suggesting that they may conserve their ability to differentiate in appropriate circumstances. Medulloblastoma cell lines may thus provide models to study the commitment and differentiation of multipotent CNS progenitor cells. A human medulloblastoma cell line, DEV, has previously been shown to differentiate in an astrocytic pathway after infection by the retrovirus HTLV-1. In this study immunofluorescence flow cytometry shows that cholera toxin beta subunit (CT beta), which binds to the ganglioside GM1, induces a twofold increase in the number of DEV cells differentiating towards a neuronal pathway, as shown by the increased proportion and labelling intensity of cells stained by an anti-neurofilament antibody. Immunocytochemistry shows that after 3 days in culture with CT beta, DEV cells develop processes which stain positive for neurofilaments and MAP-1. This suggests that CT beta induces DEV cells to express a more neuronal phenotype.
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Affiliation(s)
- N Dufay
- INSERM CJF 90-10, Laboratoire Anatomie Pathologique, Hôpital Neurologique de Lyon, France
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Levy DN, Fernandes LS, Williams WV, Weiner DB. Induction of cell differentiation by human immunodeficiency virus 1 vpr. Cell 1993; 72:541-50. [PMID: 8440020 DOI: 10.1016/0092-8674(93)90073-y] [Citation(s) in RCA: 184] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cell lines from rhabdomyosarcomas, which are tumors of muscle origin, have been used as models of CD4-independent HIV infection. These cell lines can be induced to differentiate in vitro. We report here that the vpr gene of HIV1 is sufficient for the differentiation of the human rhabdomyosarcoma cell line TE671. Differentiated cells are characterized by great enlargement, altered morphology, lack of replication, and high level expression of the muscle-specific protein myosin. We have also observed the morphological differentiation and inhibition of proliferation of two other transformed cell lines. vpr-transfected cells remain fully viable in culture for extended periods. These observations elucidate a potential role for vpr in the virus life cycle and raise the possibility that some aspects of HIV-induced pathologies may be caused by a disturbance of cells by vpr.
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Affiliation(s)
- D N Levy
- Department of Medicine, University of Pennsylvania, Philadelphia
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Giraudon P, Dufay N, Hardin H, Reboul A, Tardy M, Belin MF. Differentiation of a medulloblastoma cell line towards an astrocytic lineage using the human T lymphotropic retrovirus-1. Neuroscience 1993; 52:1069-79. [PMID: 8450975 DOI: 10.1016/0306-4522(93)90553-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Constituent cells of medulloblastoma, the most common brain tumor occurring in childhood, resemble the primitive neuroepithelial cells normally found in the developing nervous system. However, mutational events prevent their further differentiation. We used the human T cell lymphotrophic virus type 1 to activate these deregulated immature cells by means of its transactivating protein Tax. Concomitant with viral infection was a decrease in cell proliferation characterized by inhibition of [3H]thymidine incorporation and in the number of cells in the G2/M phase of the cell cycle. Morphological changes suggested that medulloblastoma cells differentiated along the astrocytic lineage. The glial phenotype was confirmed by the induction of the glial fibrillary acidic protein and the glial enzyme glutamine synthetase. A direct viral effect and/or secondary effects to viral infection via paracrine/autocrine pathways could counterbalance the maturational defect in these medulloblastoma cells.
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Affiliation(s)
- P Giraudon
- CJF 90-10 INSERM, Faculté de Médecine Alexis Carrel, Lyon, France
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12
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Lukas RJ, Bencherif M. Heterogeneity and regulation of nicotinic acetylcholine receptors. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1992; 34:25-131. [PMID: 1587717 DOI: 10.1016/s0074-7742(08)60097-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- R J Lukas
- Division of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona 85013
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13
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Bencherif M, Lukas RJ. Differential regulation of nicotinic acetylcholine receptor expression by human TE671/RD cells following second messenger modulation and sodium butyrate treatments. Mol Cell Neurosci 1991; 2:52-65. [DOI: 10.1016/1044-7431(91)90039-q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/1991] [Indexed: 11/24/2022] Open
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