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Wyart C, Carbo-Tano M, Cantaut-Belarif Y, Orts-Del'Immagine A, Böhm UL. Cerebrospinal fluid-contacting neurons: multimodal cells with diverse roles in the CNS. Nat Rev Neurosci 2023; 24:540-556. [PMID: 37558908 DOI: 10.1038/s41583-023-00723-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2023] [Indexed: 08/11/2023]
Abstract
The cerebrospinal fluid (CSF) is a complex solution that circulates around the CNS, and whose composition changes as a function of an animal's physiological state. Ciliated neurons that are bathed in the CSF - and thus referred to as CSF-contacting neurons (CSF-cNs) - are unusual polymodal interoceptive neurons. As chemoreceptors, CSF-cNs respond to variations in pH and osmolarity and to bacterial metabolites in the CSF. Their activation during infections of the CNS results in secretion of compounds to enhance host survival. As mechanosensory neurons, CSF-cNs operate together with an extracellular proteinaceous polymer known as the Reissner fibre to detect compression during spinal curvature. Once activated, CSF-cNs inhibit motor neurons, premotor excitatory neurons and command neurons to enhance movement speed and stabilize posture. At longer timescales, CSF-cNs instruct morphogenesis throughout life via the release of neuropeptides that act over long distances on skeletal muscle. Finally, recent evidence suggests that mouse CSF-cNs may act as neural stem cells in the spinal cord, inspiring new paths of investigation for repair after injury.
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Affiliation(s)
- Claire Wyart
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France.
| | - Martin Carbo-Tano
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France
| | - Yasmine Cantaut-Belarif
- Institut du Cerveau (ICM), INSERM U1127, UMR CNRS 7225 Paris, Sorbonne Université, Paris, France
| | | | - Urs L Böhm
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
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Jurčić N, Michelle C, Trouslard J, Wanaverbecq N, Kastner A. Evidence for PKD2L1-positive neurons distant from the central canal in the ventromedial spinal cord and medulla of the adult mouse. Eur J Neurosci 2021; 54:4781-4803. [PMID: 34097332 DOI: 10.1111/ejn.15342] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 05/20/2021] [Accepted: 05/23/2021] [Indexed: 11/29/2022]
Abstract
Neurons in contact with the cerebrospinal fluid (CSF) are found around the medullo-spinal central canal (CC) in adult mice. These neurons (CSF-cNs), located within or below the ependymal cell layer, known as the stem cell niche, present a characteristic morphology with a dendrite projecting to the CC and ending with a protrusion. They are GABAergic, present an intermediate neuronal maturity and selectively express PKD2L1, a member of the transient receptor potential channel superfamily with sensory properties. Using immunohistological and electrophysiological recording techniques in mice, we characterize the properties of a new population of PKD2L1 positive cells that is distant from the CC in a zone enriched with astrocytes and ependymal fibers of the ventro-medial spinal cord and medulla. They appear around embryonic day 16 and their number increases up to early postnatal days. With development and the reorganization of the CC region, they progressively become more distant from the CC, suggesting some migratory capabilities. These neurons share functional and phenotypical properties with CSF-cNs but appear subdivided in two groups. One group, present along the midline, has a bipolar morphology and extends a long dendrite along ependymal fibers and towards the CC. The second group, localized in more ventro-lateral regions, has a multipolar morphology and no apparent projection to the CC. Altogether, we describe a novel population of PKD2L1+ neurons distant from the CC but with properties similar to CSF-cNs that might serve to sense modification in the composition of either CSF or interstitial liquid, a function that will need to be confirmed.
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Affiliation(s)
- Nina Jurčić
- Institut de Neurosciences de la Timone, Aix-Marseille Univ and CNRS UMR 7289, SpiCCI Team, Marseille, France
| | - Caroline Michelle
- Institut de Neurosciences de la Timone, Aix-Marseille Univ and CNRS UMR 7289, SpiCCI Team, Marseille, France
| | - Jérôme Trouslard
- Institut de Neurosciences de la Timone, Aix-Marseille Univ and CNRS UMR 7289, SpiCCI Team, Marseille, France
| | - Nicolas Wanaverbecq
- Institut de Neurosciences de la Timone, Aix-Marseille Univ and CNRS UMR 7289, SpiCCI Team, Marseille, France
| | - Anne Kastner
- Institut de Neurosciences de la Timone, Aix-Marseille Univ and CNRS UMR 7289, SpiCCI Team, Marseille, France
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Tonelli Gombalová Z, Košuth J, Alexovič Matiašová A, Zrubáková J, Žežula I, Giallongo T, Di Giulio AM, Carelli S, Tomašková L, Daxnerová Z, Ševc J. Majority of cerebrospinal fluid‐contacting neurons in the spinal cord of
C57Bl/6N
mice is present in ectopic position unlike in other studied experimental mice strains and mammalian species. J Comp Neurol 2020; 528:2523-2550. [DOI: 10.1002/cne.24909] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Zuzana Tonelli Gombalová
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Ján Košuth
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Anna Alexovič Matiašová
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Jarmila Zrubáková
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Ivan Žežula
- Institute of Mathematics, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Toniella Giallongo
- Laboratories of Pharmacology, Department of Health SciencesUniversity of Milan Milan Italy
- Pediatric Clinical Research Center "Fondazione Romeo e Enrica Invernizzi", L. Sacco Department of Biomedical and Clinical ScienceUniversity of Milan Milan Italy
| | - Anna Maria Di Giulio
- Laboratories of Pharmacology, Department of Health SciencesUniversity of Milan Milan Italy
- Pediatric Clinical Research Center "Fondazione Romeo e Enrica Invernizzi", L. Sacco Department of Biomedical and Clinical ScienceUniversity of Milan Milan Italy
| | - Stephana Carelli
- Laboratories of Pharmacology, Department of Health SciencesUniversity of Milan Milan Italy
- Pediatric Clinical Research Center "Fondazione Romeo e Enrica Invernizzi", L. Sacco Department of Biomedical and Clinical ScienceUniversity of Milan Milan Italy
| | - Lenka Tomašková
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Zuzana Daxnerová
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
| | - Juraj Ševc
- Institute of Biology and Ecology, Faculty of ScienceP.J. Šafárik University in Košice Košice Slovak Republic
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Sharples SA, Koblinger K, Humphreys JM, Whelan PJ. Dopamine: a parallel pathway for the modulation of spinal locomotor networks. Front Neural Circuits 2014; 8:55. [PMID: 24982614 PMCID: PMC4059167 DOI: 10.3389/fncir.2014.00055] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 05/11/2014] [Indexed: 12/24/2022] Open
Abstract
The spinal cord contains networks of neurons that can produce locomotor patterns. To readily respond to environmental conditions, these networks must be flexible yet at the same time robust. Neuromodulators play a key role in contributing to network flexibility in a variety of invertebrate and vertebrate networks. For example, neuromodulators contribute to altering intrinsic properties and synaptic weights that, in extreme cases, can lead to neurons switching between networks. Here we focus on the role of dopamine in the control of stepping networks in the spinal cord. We first review the role of dopamine in modulating rhythmic activity in the stomatogastric ganglion (STG) and the leech, since work from these preparations provides a foundation to understand its role in vertebrate systems. We then move to a discussion of dopamine’s role in modulation of swimming in aquatic species such as the larval xenopus, lamprey and zebrafish. The control of terrestrial walking in vertebrates by dopamine is less studied and we review current evidence in mammals with a focus on rodent species. We discuss data suggesting that the source of dopamine within the spinal cord is mainly from the A11 area of the diencephalon, and then turn to a discussion of dopamine’s role in modulating walking patterns from both in vivo and in vitro preparations. Similar to the descending serotonergic system, the dopaminergic system may serve as a potential target to promote recovery of locomotor function following spinal cord injury (SCI); evidence suggests that dopaminergic agonists can promote recovery of function following SCI. We discuss pharmacogenetic and optogenetic approaches that could be deployed in SCI and their potential tractability. Throughout the review we draw parallels with both noradrenergic and serotonergic modulatory effects on spinal cord networks. In all likelihood, a complementary monoaminergic enhancement strategy should be deployed following SCI.
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Affiliation(s)
- Simon A Sharples
- Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Department of Comparative Biology and Experimental Medicine, University of Calgary Calgary, AB, Canada
| | - Kathrin Koblinger
- Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Department of Comparative Biology and Experimental Medicine, University of Calgary Calgary, AB, Canada
| | - Jennifer M Humphreys
- Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Department of Comparative Biology and Experimental Medicine, University of Calgary Calgary, AB, Canada
| | - Patrick J Whelan
- Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada ; Department of Comparative Biology and Experimental Medicine, University of Calgary Calgary, AB, Canada ; Department of Physiology and Pharmacology, University of Calgary Calgary, AB, Canada ; Department of Clinical Neurosciences, University of Calgary Calgary, AB, Canada
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Orts-Del’Immagine A, Kastner A, Tillement V, Tardivel C, Trouslard J, Wanaverbecq N. Morphology, distribution and phenotype of polycystin kidney disease 2-like 1-positive cerebrospinal fluid contacting neurons in the brainstem of adult mice. PLoS One 2014; 9:e87748. [PMID: 24504595 PMCID: PMC3913643 DOI: 10.1371/journal.pone.0087748] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 12/30/2013] [Indexed: 11/18/2022] Open
Abstract
The mammalian spinal cord and medulla oblongata harbor unique neurons that remain in contact with the cerebrospinal fluid (CSF-cNs). These neurons were shown recently to express a polycystin member of the TRP channels family (PKD2L1) that potentially acts as a chemo- or mechanoreceptor. Recent studies carried out in young rodents indicate that spinal CSF-cNs express immature neuronal markers that appear to persist even in adult cells. Nevertheless, little is known about the phenotype and morphological properties of medullar CSF-cNs. Using immunohistochemistry and confocal microscopy techniques on tissues obtained from three-month old PKD2L1:EGFP transgenic mice, we analyzed the morphology, distribution, localization and phenotype of PKD2L1(+) CSF-cNs around the brainstem and cervical spinal cord central canal. We show that PKD2L1(+) CSF-cNs are GABAergic neurons with a subependymal localization, projecting a dendrite towards the central canal and an axon-like process running through the parenchyma. These neurons display a primary cilium on the soma and the dendritic process appears to bear ciliary-like structures in contact with the CSF. PKD2L1(+) CSF-cNs present a conserved morphology along the length of the medullospinal central canal with a change in their density, localization and dendritic length according to the rostro-caudal axis. At adult stages, PKD2L1(+) medullar CSF-cNs appear to remain in an intermediate state of maturation since they still exhibit characteristics of neuronal immaturity (DCX positive, neurofilament 160 kDa negative) along with the expression of a marker representative of neuronal maturation (NeuN). In addition, PKD2L1(+) CSF-cNs express Nkx6.1, a homeodomain protein that enables the differentiation of ventral progenitors into somatic motoneurons and interneurons. The present study provides valuable information on the cellular properties of this peculiar neuronal population that will be crucial for understanding the physiological role of CSF-cNs in mammals and their link with the stem cells contained in the region surrounding the medullospinal central canal.
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Affiliation(s)
- Adeline Orts-Del’Immagine
- Aix-Marseille Université (AMU), Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-moteur et Neurovégétatif (PPSN) - EA 4674, Faculté des Sciences St. Jérôme, Marseille, France
| | - Anne Kastner
- Aix-Marseille Université (AMU), Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-moteur et Neurovégétatif (PPSN) - EA 4674, Faculté des Sciences St. Jérôme, Marseille, France
| | - Vanessa Tillement
- Aix-Marseille Université (AMU), Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-moteur et Neurovégétatif (PPSN) - EA 4674, Faculté des Sciences St. Jérôme, Marseille, France
| | - Catherine Tardivel
- Aix-Marseille Université (AMU), Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-moteur et Neurovégétatif (PPSN) - EA 4674, Faculté des Sciences St. Jérôme, Marseille, France
| | - Jérôme Trouslard
- Aix-Marseille Université (AMU), Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-moteur et Neurovégétatif (PPSN) - EA 4674, Faculté des Sciences St. Jérôme, Marseille, France
| | - Nicolas Wanaverbecq
- Aix-Marseille Université (AMU), Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-moteur et Neurovégétatif (PPSN) - EA 4674, Faculté des Sciences St. Jérôme, Marseille, France
- * E-mail:
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Aromatic L-amino acid decarboxylase (AADC) is crucial for brain development and motor functions. PLoS One 2013; 8:e71741. [PMID: 23940784 PMCID: PMC3734303 DOI: 10.1371/journal.pone.0071741] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/02/2013] [Indexed: 01/01/2023] Open
Abstract
Aromatic L-amino acid decarboxylase (AADC) deficiency is a rare pediatric neuro-metabolic disease in children. Due to the lack of an animal model, its pathogenetic mechanism is poorly understood. To study the role of AADC in brain development, a zebrafish model of AADC deficiency was generated. We identified an aadc gene homolog, dopa decarboxylase (ddc), in the zebrafish genome. Whole-mount in situ hybridization analysis showed that the ddc gene is expressed in the epiphysis, locus caeruleus, diencephalic catecholaminergic clusters, and raphe nuclei of 36-h post-fertilization (hpf) zebrafish embryos. Inhibition of Ddc by AADC inhibitor NSD-1015 or anti-sense morpholino oligonucleotides (MO) reduced brain volume and body length. We observed increased brain cell apoptosis and loss of dipencephalic catecholaminergic cluster neurons in ddc morphants (ddc MO-injected embryos). Seizure-like activity was also detected in ddc morphants in a dose-dependent manner. ddc morphants had less sensitive touch response and impaired swimming activity that could be rescued by injection of ddc plasmids. In addition, eye movement was also significantly impaired in ddc morphants. Collectively, loss of Ddc appears to result in similar phenotypes as that of ADCC deficiency, thus zebrafish could be a good model for investigating pathogenetic mechanisms of AADC deficiency in children.
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A regulatory toolbox of MiniPromoters to drive selective expression in the brain. Proc Natl Acad Sci U S A 2010; 107:16589-94. [PMID: 20807748 DOI: 10.1073/pnas.1009158107] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Pleiades Promoter Project integrates genomewide bioinformatics with large-scale knockin mouse production and histological examination of expression patterns to develop MiniPromoters and related tools designed to study and treat the brain by directed gene expression. Genes with brain expression patterns of interest are subjected to bioinformatic analysis to delineate candidate regulatory regions, which are then incorporated into a panel of compact human MiniPromoters to drive expression to brain regions and cell types of interest. Using single-copy, homologous-recombination "knockins" in embryonic stem cells, each MiniPromoter reporter is integrated immediately 5' of the Hprt locus in the mouse genome. MiniPromoter expression profiles are characterized in differentiation assays of the transgenic cells or in mouse brains following transgenic mouse production. Histological examination of adult brains, eyes, and spinal cords for reporter gene activity is coupled to costaining with cell-type-specific markers to define expression. The publicly available Pleiades MiniPromoter Project is a key resource to facilitate research on brain development and therapies.
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Aromatic l-amino acid decarboxylase expression profiling and isoform detection in the developing porcine brain. Brain Res 2010; 1308:1-13. [DOI: 10.1016/j.brainres.2009.10.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 10/12/2009] [Accepted: 10/19/2009] [Indexed: 02/07/2023]
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Tyramine as an independent transmitter and a precursor of octopamine in the locust central nervous system: An immunocytochemical study. J Comp Neurol 2009; 512:433-52. [DOI: 10.1002/cne.21911] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Characterization of the Regulatory Region of the Dopa Decarboxylase Gene in Medaka: An in vivo Green Fluorescent Protein Reporter Assay Combined with a Simple TA-Cloning Method. Mol Biotechnol 2008; 41:224-35. [DOI: 10.1007/s12033-008-9120-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 10/16/2008] [Indexed: 12/30/2022]
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Menheniott TR, Woodfine K, Schulz R, Wood AJ, Monk D, Giraud AS, Baldwin HS, Moore GE, Oakey RJ. Genomic imprinting of Dopa decarboxylase in heart and reciprocal allelic expression with neighboring Grb10. Mol Cell Biol 2008; 28:386-96. [PMID: 17967881 PMCID: PMC2223316 DOI: 10.1128/mcb.00862-07] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 06/14/2007] [Accepted: 10/08/2007] [Indexed: 11/20/2022] Open
Abstract
By combining a tissue-specific microarray screen with mouse uniparental duplications, we have identified a novel imprinted gene, Dopa decarboxylase (Ddc), on chromosome 11. Ddc_exon1a is a 2-kb transcript variant that initiates from an alternative first exon in intron 1 of the canonical Ddc transcript and is paternally expressed in trabecular cardiomyocytes of the embryonic and neonatal heart. Ddc displays tight conserved linkage with the maternally expressed and methylated Grb10 gene, suggesting that these reciprocally imprinted genes may be coordinately regulated. In Dnmt3L mutant embryos that lack maternal germ line methylation imprints, we show that Ddc is overexpressed and Grb10 is silenced. Their imprinting is therefore dependent on maternal germ line methylation, but the mechanism at Ddc does not appear to involve differential methylation of the Ddc_exon1a promoter region and may instead be provided by the oocyte mark at Grb10. Our analysis of Ddc redefines the imprinted Grb10 domain on mouse proximal chromosome 11 and identifies Ddc_exon1a as the first example of a heart-specific imprinted gene.
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Affiliation(s)
- Trevelyan R Menheniott
- King's College London, Department of Medical and Molecular Genetics, 8th Floor Guy's Tower, London SE1 9RT, England
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Alkema MJ, Hunter-Ensor M, Ringstad N, Horvitz HR. Tyramine Functions Independently of Octopamine in the Caenorhabditis elegans Nervous System. Neuron 2005; 46:247-60. [PMID: 15848803 DOI: 10.1016/j.neuron.2005.02.024] [Citation(s) in RCA: 265] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 12/23/2004] [Accepted: 02/18/2005] [Indexed: 10/25/2022]
Abstract
Octopamine biosynthesis requires tyrosine decarboxylase to convert tyrosine into tyramine and tyramine beta-hydroxylase to convert tyramine into octopamine. We identified and characterized a Caenorhabditis elegans tyrosine decarboxylase gene, tdc-1, and a tyramine beta-hydroxylase gene, tbh-1. The TBH-1 protein is expressed in a subset of TDC-1-expressing cells, indicating that C. elegans has tyraminergic cells that are distinct from its octopaminergic cells. tdc-1 mutants have behavioral defects not shared by tbh-1 mutants. We show that tyramine plays a specific role in the inhibition of egg laying, the modulation of reversal behavior, and the suppression of head oscillations in response to anterior touch. We propose a model for the neural circuit that coordinates locomotion and head oscillations in response to anterior touch. Our findings establish tyramine as a neurotransmitter in C. elegans, and we suggest that tyramine is a genuine neurotransmitter in other invertebrates and possibly in vertebrates as well.
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Affiliation(s)
- Mark J Alkema
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Dugast-Darzacq C, Egloff S, Weber MJ. Cooperative dimerization of the POU domain protein Brn-2 on a new motif activates the neuronal promoter of the human aromatic L-amino acid decarboxylase gene. ACTA ACUST UNITED AC 2004; 120:151-63. [PMID: 14741405 DOI: 10.1016/j.molbrainres.2003.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The neuronal promoter of the human aromatic L-amino acid decarboxylase (AADC) gene contains a perfectly palindromic element (TB) that conforms to the structure of a POU domain protein binding site of the MORE+2 type. The TB motif (located at nts -900/-872 relative to the neuronal cap site) bears striking similarities with the dimeric Pit-1 binding site from growth hormone gene promoter (GH-1), and it enhanced the activity of the minimal tk promoter in transfected SK-N-BE neuroblastoma cells. In transfected COS-7 cells, the expression of a 3xTB-tk-luc was stimulated up to 11-fold by the overexpressed Brn-2 protein. In AADC gene neuronal promoter, we previously characterized a bipartite regulatory element (ONF for octamer-like/NF-Y, nts -86/-57) that binds Brn-2 and NF-Y proteins in a cooperative manner. We now show that both TB and ONF sites participate in the activation of the neuronal promoter by Brn-2. EMSA experiments showed that the recombinant Brn-2 POU domain dimerized on the TB element in a cooperative manner. By site directed mutagenesis of the POU domain of Brn-2, the dimerization interface on the TB element was localized to the hydrophobic pocket of the POU specific domain and the C-terminal part of the POU homeodomain.
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Affiliation(s)
- Claire Dugast-Darzacq
- Laboratoire de Biologie Moléculaire Eucaryote, CNRS UMR 5099/IFR 109, 118 route de Narbonne, 31062, Cedex, Toulouse, France.
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