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H 2O 2 and Engrailed 2 paracrine activity synergize to shape the zebrafish optic tectum. Commun Biol 2020; 3:536. [PMID: 32994473 PMCID: PMC7524761 DOI: 10.1038/s42003-020-01268-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 09/02/2020] [Indexed: 12/23/2022] Open
Abstract
Although a physiological role for redox signaling is now clearly established, the processes sensitive to redox signaling remains to be identified. Ratiometric probes selective for H2O2 have revealed its complex spatiotemporal dynamics during neural development and adult regeneration and perturbations of H2O2 levels disturb cell plasticity and morphogenesis. Here we ask whether endogenous H2O2 could participate in the patterning of the embryo. We find that perturbations of endogenous H2O2 levels impact on the distribution of the Engrailed homeoprotein, a strong determinant of midbrain patterning. Engrailed 2 is secreted from cells with high H2O2 levels and taken up by cells with low H2O2 levels where it leads to increased H2O2 production, steering the directional spread of the Engrailed gradient. These results illustrate the interplay between protein signaling pathways and metabolic processes during morphogenetic events.
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2
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Rampon C, Gauron C, Lin T, Meda F, Dupont E, Cosson A, Ipendey E, Frerot A, Aujard I, Le Saux T, Bensimon D, Jullien L, Volovitch M, Vriz S, Joliot A. Control of brain patterning by Engrailed paracrine transfer: a new function of the Pbx interaction domain. Development 2015; 142:1840-9. [PMID: 25926358 PMCID: PMC4440920 DOI: 10.1242/dev.114181] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 03/02/2015] [Indexed: 12/28/2022]
Abstract
Homeoproteins of the Engrailed family are involved in the patterning of mesencephalic boundaries through a mechanism classically ascribed to their transcriptional functions. In light of recent reports on the paracrine activity of homeoproteins, including Engrailed, we asked whether Engrailed intercellular transfer was also involved in brain patterning and boundary formation. Using time-controlled activation of Engrailed combined with tools that block its transfer, we show that the positioning of the diencephalic-mesencephalic boundary (DMB) requires Engrailed paracrine activity. Both zebrafish Eng2a and Eng2b are competent for intercellular transfer in vivo, but only extracellular endogenous Eng2b, and not Eng2a, participates in DMB positioning. In addition, disruption of the Pbx-interacting motif in Engrailed, known to strongly reduce the gain-of-function phenotype, also downregulates Engrailed transfer, thus revealing an unsuspected participation of the Pbx interaction domain in this pathway.
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Affiliation(s)
- Christine Rampon
- Université Paris Diderot, Sorbonne Paris Cité, Paris 75205, Cedex 13, France Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Carole Gauron
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Thibault Lin
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Francesca Meda
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France École Normale Supérieure, Institute of Biology at the Ecole Normale Supérieure (IBENS), CNRS UMR8197, INSERM U1024, PSL Research University, Paris F-75005, France
| | - Edmond Dupont
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Adrien Cosson
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Eliane Ipendey
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France École Normale Supérieure, Institute of Biology at the Ecole Normale Supérieure (IBENS), CNRS UMR8197, INSERM U1024, PSL Research University, Paris F-75005, France
| | - Alice Frerot
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Isabelle Aujard
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, UMR 8640 CNRS-ENS-UPMC PASTEUR, 24, rue Lhomond, Paris 75005, France
| | - Thomas Le Saux
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, UMR 8640 CNRS-ENS-UPMC PASTEUR, 24, rue Lhomond, Paris 75005, France
| | - David Bensimon
- École Normale Supérieure, Institute of Biology at the Ecole Normale Supérieure (IBENS), CNRS UMR8197, INSERM U1024, PSL Research University, Paris F-75005, France Laboratoire de Physique Statistique, UMR CNRS-ENS 8550, Paris F-75005, France Department of Chemistry and Biochemistry, UCLA, Los Angeles, CA 90095-1569, USA
| | - Ludovic Jullien
- Ecole Normale Supérieure-PSL Research University, Département de Chimie, UMR 8640 CNRS-ENS-UPMC PASTEUR, 24, rue Lhomond, Paris 75005, France
| | - Michel Volovitch
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France École Normale Supérieure, Institute of Biology at the Ecole Normale Supérieure (IBENS), CNRS UMR8197, INSERM U1024, PSL Research University, Paris F-75005, France
| | - Sophie Vriz
- Université Paris Diderot, Sorbonne Paris Cité, Paris 75205, Cedex 13, France Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
| | - Alain Joliot
- Center for Interdisciplinary Research in Biology (CIRB) - CNRS UMR 7241, INSERM U1050, Labex MemoLife, PSL Research University, Collège de France, Paris F-75005, France
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3
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Villarroel-Campos D, Gonzalez-Billault C. The MAP1B case: an old MAP that is new again. Dev Neurobiol 2014; 74:953-71. [PMID: 24700609 DOI: 10.1002/dneu.22178] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/27/2014] [Accepted: 03/31/2014] [Indexed: 12/24/2022]
Abstract
The functions of microtubule-associated protein 1B (MAP1B) have historically been linked to the development of the nervous system, based on its very early expression in neurons and glial cells. Moreover, mice in which MAP1B is genetically inactivated have been used extensively to show its role in axonal elongation, neuronal migration, and axonal guidance. In the last few years, it has become apparent that MAP1B has other cellular and molecular functions that are not related to its microtubule-stabilizing properties in the embryonic and adult brain. In this review, we present a systematic review of the canonical and novel functions of MAP1B and propose that, in addition to regulating the polymerization of microtubule and actin microfilaments, MAP1B also acts as a signaling protein involved in normal physiology and pathological conditions in the nervous system.
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Affiliation(s)
- David Villarroel-Campos
- Laboratory of Cell and Neuronal Dynamics (Cenedyn), Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
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4
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Fournier L, Gauron C, Xu L, Aujard I, Le Saux T, Gagey-Eilstein N, Maurin S, Dubruille S, Baudin JB, Bensimon D, Volovitch M, Vriz S, Jullien L. A blue-absorbing photolabile protecting group for in vivo chromatically orthogonal photoactivation. ACS Chem Biol 2013; 8:1528-36. [PMID: 23651265 DOI: 10.1021/cb400178m] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The small and synthetically easily accessible 7-diethylamino-4-thiocoumarinylmethyl photolabile protecting group has been validated for uncaging with blue light. It exhibits a significant action cross-section for uncaging in the 470-500 nm wavelength range and a low light absorption between 350 and 400 nm. These attractive features have been implemented in living zebrafish embryos to perform chromatic orthogonal photoactivation of two biologically active species controlling biological development with UV and blue-cyan light sources, respectively.
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Affiliation(s)
- Ludovic Fournier
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
| | - Carole Gauron
- Collège de France, Center
for Interdisciplinary Research in Biology (CIRB), CNRS, UMR 7241, INSERM, U1050, 11, Place Marcelin Berthelot,
75231 Paris Cedex 05, France
| | - Lijun Xu
- Ecole Normale Supérieure,
Département de Physique and Département de Biologie,
Laboratoire de Physique Statistique, UMR CNRS-ENS 8550, 24 rue Lhomond, F-75231 Paris, France
| | - Isabelle Aujard
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
| | - Thomas Le Saux
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
- UPMC, 4, Place Jussieu,
75232 Paris Cedex 05, France,
| | - Nathalie Gagey-Eilstein
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
| | - Sylvie Maurin
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
| | - Sylvie Dubruille
- Institut Curie, Centre de Recherche, CNRS, UMR 176, 26, rue d’Ulm, Paris F-75248,
France
| | - Jean-Bernard Baudin
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
| | - David Bensimon
- Ecole Normale Supérieure,
Département de Physique and Département de Biologie,
Laboratoire de Physique Statistique, UMR CNRS-ENS 8550, 24 rue Lhomond, F-75231 Paris, France
- Department of Chemistry
and Biochemistry, University of California, Los Angeles, Los Angeles,
California, United States
| | - Michel Volovitch
- Collège de France, Center
for Interdisciplinary Research in Biology (CIRB), CNRS, UMR 7241, INSERM, U1050, 11, Place Marcelin Berthelot,
75231 Paris Cedex 05, France
| | - Sophie Vriz
- Collège de France, Center
for Interdisciplinary Research in Biology (CIRB), CNRS, UMR 7241, INSERM, U1050, 11, Place Marcelin Berthelot,
75231 Paris Cedex 05, France
| | - Ludovic Jullien
- Ecole Normale Supérieure,
Département de Chimie, UMR CNRS-ENS-UPMC 8640 PASTEUR, 24, rue Lhomond, 75231 Paris Cedex 05, France
- UPMC, 4, Place Jussieu,
75232 Paris Cedex 05, France,
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5
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Di Lullo E, Haton C, Le Poupon C, Volovitch M, Joliot A, Thomas JL, Prochiantz A. Paracrine Pax6 activity regulates oligodendrocyte precursor cell migration in the chick embryonic neural tube. Development 2011; 138:4991-5001. [PMID: 22028031 DOI: 10.1242/dev.066282] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Homeoprotein transcription factors play fundamental roles in development, ranging from embryonic polarity to cell differentiation and migration. Research in recent years has underscored the physiological importance of homeoprotein intercellular transfer in eye field development, axon guidance and retino-tectal patterning, and visual cortex plasticity. Here, we have used the embryonic chick neural tube to investigate a possible role for homeoprotein Pax6 transfer in oligodendrocyte precursor cell (OPC) migration. We report the extracellular expression of Pax6 and the effects of gain and loss of extracellular Pax6 activity on OPCs. Open book cultures with recombinant Pax6 protein or Pax6 blocking antibodies, as well as in ovo gene transfer experiments involving expression of secreted Pax6 protein or secreted Pax6 antibodies, provide converging evidences that OPC migration is promoted by extracellular Pax6. The paracrine effect of Pax6 on OPC migration is thus a new example of direct non-cell autonomous homeoprotein activity.
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Affiliation(s)
- Elizabeth Di Lullo
- Collège de France, Center for Interdisciplinary Research in Biology, 11 place Marcelin Berthelot, Paris F-75005, France
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6
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Merianda TT, Lin AC, Lam JSY, Vuppalanchi D, Willis DE, Karin N, Holt CE, Twiss JL. A functional equivalent of endoplasmic reticulum and Golgi in axons for secretion of locally synthesized proteins. Mol Cell Neurosci 2008; 40:128-42. [PMID: 19022387 DOI: 10.1016/j.mcn.2008.09.008] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 09/26/2008] [Indexed: 12/27/2022] Open
Abstract
Subcellular localization of protein synthesis provides a means to regulate the protein composition in far reaches of a cell. This localized protein synthesis gives neuronal processes autonomy to rapidly respond to extracellular stimuli. Locally synthesized axonal proteins enable neurons to respond to guidance cues and can help to initiate regeneration after injury. Most studies of axonal mRNA translation have concentrated on cytoplasmic proteins. While ultrastructural studies suggest that axons do not have rough endoplasmic reticulum or Golgi apparatus, mRNAs for transmembrane and secreted proteins localize to axons. Here, we show that growing axons with protein synthetic activity contain ER and Golgi components needed for classical protein synthesis and secretion. Isolated axons have the capacity to traffic locally synthesized proteins into secretory pathways and inhibition of Golgi function attenuates translation-dependent axonal growth responses. Finally, the capacity for secreting locally synthesized proteins in axons appears to be increased by injury.
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Affiliation(s)
- Tanuja T Merianda
- Nemours Biomedical Research, Alfred I duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19803, USA
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7
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Holst MI, Maercker C, Pintea B, Masseroli M, Liebig C, Jankowski J, Miething A, Martini J, Schwaller B, Oberdick J, Schilling K, Baader SL. Engrailed-2 regulates genes related to vesicle formation and transport in cerebellar Purkinje cells. Mol Cell Neurosci 2008; 38:495-504. [DOI: 10.1016/j.mcn.2008.04.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2008] [Revised: 04/23/2008] [Accepted: 04/24/2008] [Indexed: 11/25/2022] Open
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8
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Wei ZX, Yi YH, Sun WW, Wang R, Su T, Bai YJ, Liao WP. Expression changes of microtubule associated protein 1B in the brain of Fmr1 knockout mice. Neurosci Bull 2008; 23:203-8. [PMID: 17687394 PMCID: PMC5550582 DOI: 10.1007/s12264-007-0030-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE To explore the regulatory effect of fragile X mental retardation protein (FMRP) on the translation of microtubule associated protein 1B (MAP1B). METHODS The expressions of MAP1B protein and MAP1B mRNA in the brains of 1-week and 6-week old fragile X mental retardation-1 (Fmr1) knockout (KO) mice were investigated by immunohistochemistry, Western blot, and in situ hybridization, with the age-matched wild type mice (WT) as controls. RESULTS The mean optical density (MOD) of MAP1B was significantly decreased in each brain region in KO6W compared with WT6W, whereas in KO1W, this decrease was only found in the hippocampus and cerebellum. MAP1B in 6-week mice was much less than that in 1-week mice of the same genotype. The results of Western blot and in situ hybridization showed that MAP1B protein and MAP1B mRNA were significantly decreased in the hippocampus of both KO1W and KO6W. CONCLUSION The decreased MAP1B protein and MAP1B mRNA in the Fmr1 knockout mice indicate that FMRP may positively regulate the expression of MAP1B.
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Affiliation(s)
- Zhao-Xia Wei
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
| | - Yong-Hong Yi
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
| | - Wei-Wen Sun
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
| | - Rong Wang
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
| | - Tao Su
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
| | - Yong-Jie Bai
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
| | - Wei-Ping Liao
- Neurology Department of the Second Affiliated Hospital and Institute of Neuroscience of Guangzhou Medical College, Guangzhou, 510260 China
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9
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Riederer BM. Microtubule-associated protein 1B, a growth-associated and phosphorylated scaffold protein. Brain Res Bull 2006; 71:541-58. [PMID: 17292797 DOI: 10.1016/j.brainresbull.2006.11.012] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 11/28/2006] [Indexed: 11/25/2022]
Abstract
Microtubule-associated protein 1B, MAP1B, is one of the major growth associated and cytoskeletal proteins in neuronal and glial cells. It is present as a full length protein or may be fragmented into a heavy chain and a light chain. It is essential to stabilize microtubules during the elongation of dendrites and neurites and is involved in the dynamics of morphological structures such as microtubules, microfilaments and growth cones. MAP1B function is modulated by phosphorylation and influences microtubule stability, microfilaments and growth cone motility. Considering its large size, several interactions with a variety of other proteins have been reported and there is increasing evidence that MAP1B plays a crucial role in the stability of the cytoskeleton and may have other cellular functions. Here we review molecular and functional aspects of this protein, evoke its role as a scaffold protein and have a look at several pathologies where the protein may be involved.
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Affiliation(s)
- Beat M Riederer
- Département de Biologie Cellulaire et de Morphologi), Université de Lausanne, 9 rue du Bugnon, CH-1005 Lausanne, Switzerland.
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10
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Zhao L, Ku L, Chen Y, Xia M, LoPresti P, Feng Y. QKI binds MAP1B mRNA and enhances MAP1B expression during oligodendrocyte development. Mol Biol Cell 2006; 17:4179-86. [PMID: 16855020 PMCID: PMC1635361 DOI: 10.1091/mbc.e06-04-0355] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Microtubule-associated protein 1B (MAP1B) is essential for neural development. Besides the abundant expression in neurons, MAP1B recently was found in myelinating oligodendroglia. Moreover, MAP1B deficiency causes delayed myelin development, suggesting the functional importance of MAP1B in oligodendroglia. However, molecular mechanisms that control MAP1B expression in oligodendroglia remain elusive. We report here that MAP1B mRNA is markedly up-regulated in the oligodendroglia cell line CG4 upon induced differentiation, leading to elevated MAP1B protein production. A coordinated regulation of homeoprotein transcription factors was observed during CG4 cell differentiation, which recapitulates the regulation in neurons that promotes MAP1B transcription. Hence, transcriptional regulation of MAP1B appears to be a common mechanism in both neurons and oligodendroglia. In addition, we found posttranscriptional regulation of MAP1B mRNA by the selective RNA-binding protein QKI in oligodendroglia. The 3'UTR of MAP1B mRNA interacts with QKI, and oligodendroglia-specific QKI-deficiency in the quakingviable mutant mice resulted in reduced MAP1B mRNA expression. Moreover, RNAi-mediated QKI-knockdown caused destabilization of the MAP1B mRNA in CG4 cells. Furthermore, forced expression of exogenous QKI was sufficient for promoting MAP1B expression. Because QKI is absent in neurons, QKI-dependent stabilization of MAP1B mRNA provides a novel mechanism for advancing MAP1B expression specifically in oligodendroglia during brain development.
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Affiliation(s)
- Lixia Zhao
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Li Ku
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Yuntao Chen
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | - Mingjing Xia
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
| | | | - Yue Feng
- *Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322; and
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11
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Brunet I, Weinl C, Piper M, Trembleau A, Volovitch M, Harris W, Prochiantz A, Holt C. The transcription factor Engrailed-2 guides retinal axons. Nature 2005; 438:94-8. [PMID: 16267555 PMCID: PMC3785142 DOI: 10.1038/nature04110] [Citation(s) in RCA: 216] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 08/04/2005] [Indexed: 11/08/2022]
Abstract
Engrailed-2 (En-2), a homeodomain transcription factor, is expressed in a caudal-to-rostral gradient in the developing midbrain, where it has an instructive role in patterning the optic tectum--the target of topographic retinal input. In addition to its well-known role in regulating gene expression through its DNA-binding domain, En-2 may also have a role in cell-cell communication, as suggested by the presence of other domains involved in nuclear export, secretion and internalization. Consistent with this possibility, here we report that an external gradient of En-2 protein strongly repels growth cones of Xenopus axons originating from the temporal retina and, conversely, attracts nasal axons. Fluorescently tagged En-2 accumulates inside growth cones within minutes of exposure, and a mutant form of the protein that cannot enter cells fails to elicit axon turning. Once internalized, En-2 stimulates the rapid phosphorylation of proteins involved in translation initiation and triggers the local synthesis of new proteins. Furthermore, the turning responses of both nasal and temporal growth cones in the presence of En-2 are blocked by inhibitors of protein synthesis. The differential guidance of nasal and temporal axons reported here suggests that En-2 may participate directly in topographic map formation in the vertebrate visual system.
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Affiliation(s)
- Isabelle Brunet
- CNRS UMR 8542, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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12
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Lu R, Wang H, Liang Z, Ku L, O'donnell WT, Li W, Warren ST, Feng Y. The fragile X protein controls microtubule-associated protein 1B translation and microtubule stability in brain neuron development. Proc Natl Acad Sci U S A 2004; 101:15201-6. [PMID: 15475576 PMCID: PMC524058 DOI: 10.1073/pnas.0404995101] [Citation(s) in RCA: 245] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2004] [Indexed: 01/28/2023] Open
Abstract
The fragile X mental retardation protein (FMRP) is a selective RNA-binding protein implicated in regulating translation of its mRNA ligands. The absence of FMRP results in fragile X syndrome, one of the leading causes of inherited mental retardation. Delayed dendritic spine maturation was found in fragile X mental retardation patients as well as in Fmr1 knockout (KO) mice, indicating the functional requirement of FMRP in synaptic development. However, the biochemical link between FMRP deficiency and the neuronal impairment during brain development has not been defined. How FMRP governs normal synapse development in the brain remains elusive. We report here that the developmentally programmed FMRP expression represses the translation of microtubule associated protein 1B (MAP1B) and is required for the accelerated decline of MAP1B during active synaptogenesis in neonatal brain development. The lack of FMRP results in misregulated MAP1B translation and delayed MAP1B decline in the Fmr1 KO brain. Furthermore, the aberrantly elevated MAP1B protein expression leads to abnormally increased microtubule stability in Fmr1 KO neurons. Together, these results indicate that FMRP plays critical roles in controlling cytoskeleton organization during neuronal development, and the abnormal microtubule dynamics is a conceivable underlying factor for the pathogenesis of fragile X mental retardation.
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Affiliation(s)
- Robert Lu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
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13
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Abstract
During the past fifteen years, a variety of peptides have been characterized for their ability to translocate into live cells. Most are efficient vectors that can internalize hydrophilic cargoes, and so provide a valuable biological (and potentially therapeutic) tool for targeting proteins into cells. Furthermore, translocation of cell-permeable peptides across the plasma membrane and their subsequent access to the cytosol, even when fused to large hydrophilic proteins, is challenging the perception of the plasma membrane as an impermeable barrier.
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Affiliation(s)
- Alain Joliot
- Homeoprotein Cell Biology Group, CNRS UMR 8542, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris, Cedex 05 France.
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14
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Gonzalez-Billault C, Jimenez-Mateos EM, Caceres A, Diaz-Nido J, Wandosell F, Avila J. Microtubule-associated protein 1B function during normal development, regeneration, and pathological conditions in the nervous system. ACTA ACUST UNITED AC 2004; 58:48-59. [PMID: 14598369 DOI: 10.1002/neu.10283] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Microtubule-associated protein 1B is the first MAP to be expressed during the development of the nervous system. Several different approaches have revealed that MAP1B function is associated with microtubule and actin microfilament polymerization and dynamics. In recent years, the generation of molecular models to inactivate MAP1B function in invertebrates and mammals has sparked some controversy about the real role of MAP1B. Despite discrepancies between some studies, it is clear that MAP1B plays a principal role in the development of the nervous system. In this article, we summarize the evidence for MAP1B function in a wide variety of cellular processes implicated in the proper construction of the nervous system. We also discuss the role of MAP1B in pathological processes.
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15
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Jankowski J, Holst MI, Liebig C, Oberdick J, Baader SL. Engrailed-2 negatively regulates the onset of perinatal Purkinje cell differentiation. J Comp Neurol 2004; 472:87-99. [PMID: 15024754 DOI: 10.1002/cne.20059] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The transcription factor Engrailed-2 is expressed in cerebellar Purkinje cells (PCs) throughout embryonic development but is downregulated in PCs after birth. Since the onset of PC differentiation coincides with this change of gene expression, we asked whether downregulation of Engrailed-2 is necessary for proper timing of PC differentiation. To investigate this, we used an L7En-2 transgenic mouse model in which Engrailed-2 expression in PCs is maintained beyond the day of birth. In these L7En-2 mice the onset of parvalbumin expression was delayed in all PCs by about 3 days; the spatial expression pattern, however, remained comparable to wildtype cerebella. Furthermore, parvalbumin expression resembled the known pattern of normal PC maturation, suggesting a direct link between parvalbumin expression and PC differentiation. Consistent with a delay of PC differentiation, we found that PCs of L7En-2 cerebella displayed a reduced tendency to align in the typical monolayer. The average size of L7En-2 PCs was reduced and the dendritic arbor developed more slowly than in wildtype PCs. In contrast, major morphological features of PCs were comparable in L7En-2 and wildtype cerebella after postnatal day 11. In addition, we observed a transient reduction of PC survival in organotypic slice cultures of L7En-2 cerebella in comparison with wildtype slice cultures. Since PC survival parallels PC differentiation in vitro, we propose that the observed delay in PC differentiation upon Engrailed-2 overexpression is an intrinsic property of Engrailed-2 activity, and that downregulation of Engrailed-2 in wildtype PCs around the day of birth is critical for the timing of distinct steps of PC differentiation.
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Affiliation(s)
- Jakob Jankowski
- Institute of Anatomy, Anatomy and Cell Biology, University of Bonn, 53115 Bonn, Germany
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Emery DL, Royo NC, Fischer I, Saatman KE, McIntosh TK. Plasticity following Injury to the Adult Central Nervous System: Is Recapitulation of a Developmental State Worth Promoting? J Neurotrauma 2003; 20:1271-92. [PMID: 14748977 DOI: 10.1089/089771503322686085] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The adult central nervous system (CNS) appears to initiate a transient increase in plasticity following injury, including increases in growth-related proteins and generation of new cells. Recent evidence is reviewed that the injured adult CNS exhibits events and patterns of gene expression that are also observed during development and during regeneration following damage to the mature peripheral nervous system (PNS). The growth of neurons during development or regeneration is correlated, in part, with a coordinated expression of growth-related proteins, such as growth-associated-protein-43 (GAP-43), microtubule-associated-protein-1B (MAP1B), and polysialylated-neural-cell-adhesion-molecule (PSA-NCAM). For each of these proteins, evidence is discussed regarding its specific role in neuronal development, signals that modify its expression, and reappearance following injury. The rate of adult hippocampal neurogenesis is also affected by numerous endogenous and exogenous factors including injury. The continuing study of developmental neurobiology will likely provide further gene and protein targets for increasing plasticity and regeneration in the mature adult CNS.
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Affiliation(s)
- Dana L Emery
- Head Injury Center, Department of Neurosurgery, University of Pennsylvania, USA
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17
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Foucher I, Montesinos ML, Volovitch M, Prochiantz A, Trembleau A. Joint regulation of the MAP1B promoter by HNF3beta/Foxa2 and Engrailed is the result of a highly conserved mechanism for direct interaction of homeoproteins and Fox transcription factors. Development 2003; 130:1867-76. [PMID: 12642491 DOI: 10.1242/dev.00414] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The MAP1B (Mtap1b) promoter presents two evolutionary conserved overlapping homeoproteins and Hepatocyte nuclear factor 3beta (HNF3beta/Foxa2) cognate binding sites (defining putative homeoprotein/Fox sites, HF1 and HF2). Accordingly, the promoter domain containing HF1 and HF2 is recognized by cerebellum nuclear extracts containing Engrailed and Foxa2 and has regulatory functions in primary cultures of embryonic mesmetencephalic nerve cells. Transfection experiments further demonstrate that Engrailed and Foxa2 interact physiologically in a dose-dependent manner: Foxa2 antagonizes the Engrailed-driven regulation of the MAP1B promoter, and vice versa. This led us to investigate if Engrailed and Foxa2 interact directly. Direct interaction was confirmed by pull-down experiments, and the regions participating in this interaction were identified. In Foxa2 the interacting domain is the Forkhead box DNA-binding domain. In Engrailed, two independent interacting domains exist: the homeodomain and a region that includes the Pbx-binding domain. Finally, Foxa2 not only binds Engrailed but also Lim1, Gsc and Hoxa5 homeoproteins and in the four cases Foxa2 binds at least the homeodomain. Based on the involvement of conserved domains in both classes of proteins, it is proposed that the interaction between Forkhead box transcription factors and homeoproteins is a general phenomenon.
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Affiliation(s)
- Isabelle Foucher
- CNRS UMR 8542, Ecole Normale Supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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18
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Nakayama A, Murakami H, Maeyama N, Yamashiro N, Sakakibara A, Mori N, Takahashi M. Role for RFX transcription factors in non-neuronal cell-specific inactivation of the microtubule-associated protein MAP1A promoter. J Biol Chem 2003; 278:233-40. [PMID: 12411430 DOI: 10.1074/jbc.m209574200] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Microtubule-associated protein MAP1A is expressed abundantly in mature neurons and is necessary for maintenance of neuronal morphology and localization of some molecules in association with the microtubule-based cytoskeleton. Previous studies indicated that its complementary expression together with MAP1B during nervous system development is regulated at the transcriptional level and that the mouse Map1A gene is transcribed under the control of 5' and intronic promoters. In this study, we investigated the regulatory mechanisms that govern the neuronal cell-specific activation of the MAP1A 5' promoter. We found that two regulatory factor for X box (RFX) binding sites in exon1 of both the mouse and human genes are important for effective transcriptional repression observed only in non-neuronal cells by reporter assays. Among RFX transcription factor family members, RFX1 and 3 mainly interact with repressive elements in vitro. Cotransfection studies indicated that RFX1, which is expressed ubiquitously, down-regulated the MAP1A 5' promoter activity in non-neuronal cells. Unexpectedly, RFX3, which is abundantly expressed in neuronal cells, down-regulated the transactivity as well, when it was expressed in non-neuronal cells. Both RFX1 and 3 did not down-regulate the transactivity in neuronal cells. These results suggest that RFX1 and 3 are pivotal factors in down-regulation of the MAP1A 5' promoter in non-neuronal cells. The cell type-specific down-regulation, however, does not depend simply on which RFX interacts with the elements, but seems to depend on underlying profound mechanisms.
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Affiliation(s)
- Atsuo Nakayama
- Department of Pathology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Aichi, Japan.
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19
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Foucher I, Volovitch M, Frain M, Kim JJ, Souberbielle JC, Gan L, Unterman TG, Prochiantz A, Trembleau A. Hoxa5 overexpression correlates with IGFBP1 upregulation and postnatal dwarfism: evidence for an interaction between Hoxa5 and Forkhead box transcription factors. Development 2002; 129:4065-74. [PMID: 12163409 DOI: 10.1242/dev.129.17.4065] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Transgenic mice expressing the homeobox gene Hoxa5 under the control of Hoxb2 regulatory elements present a growth arrest during weeks two and three of postnatal development, resulting in proportionate dwarfism. These mice present a liver phenotype illustrated by a 12-fold increase in liver insulin-like growth factor binding protein 1 (IGFBP1) mRNA and a 50% decrease in liver insulin-like growth factor 1 (IGF1) mRNA correlated with a 50% decrease in circulating IGF1. We show that the Hoxa5 transgene is expressed in the liver of these mice, leading to an overexpression of total (endogenous plus transgene) Hoxa5 mRNA in this tissue. We have used several cell lines to investigate a possible physiological interaction of Hoxa5 with the main regulator of IGFBP1 promoter activity, the Forkhead box transcription factor FKHR. In HepG2 cells, Hoxa5 has little effect by itself but inhibits the FKHR-dependent activation of the IGFBP1 promoter. In HuF cells, Hoxa5 cooperates with FKHR to dramatically enhance IGFBP1 promoter activity. This context-dependent physiological interaction probably corresponds to the existence of a direct interaction between Hoxa5 and FKHR and FoxA2/HNF3β, as demonstrated by pull-down experiments achieved either in vitro or after cellular co-expression. In conclusion, we propose that the impaired growth observed in this transgenic line relates to a liver phenotype best explained by a direct interaction between Hoxa5 and liver-specific Forkhead box transcription factors, in particular FKHR but also Foxa2/HNF3β. Because Hoxa5 and homeogenes of the same paralog group are normally expressed in the liver, the present results raise the possibility that homeoproteins, in addition to their established role during early development, regulate systemic physiological functions.
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Affiliation(s)
- Isabelle Foucher
- CNRS UMR 8542, Ecole normale supérieure, 46 rue d'Ulm, 75230 Paris Cedex 05, France
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Picker A, Scholpp S, Böhli H, Takeda H, Brand M. A novel positive transcriptional feedback loop in midbrain-hindbrain boundary development is revealed through analysis of the zebrafish pax2.1 promoter in transgenic lines. Development 2002; 129:3227-39. [PMID: 12070097 DOI: 10.1242/dev.129.13.3227] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pax2.1 gene encodes a paired-box transcription factor that is one of the earliest genes to be specifically activated in development of the midbrain and midbrain-hindbrain boundary (MHB), and is required for the development and organizer activity of this territory. To understand how this spatially restricted transcriptional activity of pax2.1 is achieved, we have isolated and characterized the pax2.1-promoter using a lacZ and a GFP reporter gene in transient injection assays and transgenic lines. Stable transgenic expression of this reporter gene shows that a 5.3-kb fragment of the 5′ region contains most, but not all, elements required for driving pax2.1 expression. The expressing tissues include the MHB, hindbrain, spinal cord, ear and pronephros. Transgene activation in the pronephros and developing ear suggests that these pax2.1-expressing tissues are composed of independently regulated subdomains. In addition, ectopic but spatially restricted activation of the reporter genes in rhombomeres 3 and 5 and in the forebrain, which do not normally express endogenous pax2.1, demonstrates the importance of negative regulation of pax2.1.
Comparison of transgene expression in wild-type and homozygous pax2.1 mutant no isthmus (noi) embryos reveals that the transgene contains control element(s) for a novel, positive transcriptional feedback loop in MHB development. Transcription of endogenous pax2.1 at the MHB is known to be initially Pax2.1 independent, during activation in late gastrulation. In contrast, transgene expression requires the endogenous Pax2.1 function. Transplantations, mRNA injections and morpholino knock-down experiments show that this feedback regulation of pax2.1 transcription occurs cell-autonomously, and that it requires eng2 and eng3 as known targets for Pax2.1 regulation. We suggest that this novel feedback loop may allow continuation of pax2.1 expression, and hence development of the MHB organizer, to become independent of the patterning machinery of the gastrula embryo.
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Affiliation(s)
- Alexander Picker
- Max-Planck-Institute of Molecular Cell Biology and Genetics (Dresden), Pfotenhauerstr. 108, 01307 Dresden, Germany
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