title: Individual Neuronal Subtypes Exhibit Diversity in CNS Myelination Mediated by Synaptic Vesicle Release.
abstract: Regulation of myelination by oligodendrocytes in the CNS has important consequences for higher-order nervous system function (e.g., [1-4]), and there is growing consensus that neuronal activity regulates CNS myelination (e.g., [5-9]) through local axon-oligodendrocyte synaptic-vesicle-release-mediated signaling [10-12]. Recent analyses have indicated that myelination along axons of distinct neuronal subtypes can differ [13, 14], but it is not known whether regulation of myelination by activity is common to all neuronal subtypes or only some. This limits insight into how specific neurons regulate their own conduction. Here, we use a novel fluorescent fusion protein reporter to study myelination along the axons of distinct neuronal subtypes over time in zebrafish. We find that the axons of reticulospinal and commissural primary ascending (CoPA) neurons are among the first myelinated in the zebrafish CNS. To investigate how activity regulates myelination by different neuronal subtypes, we express tetanus toxin (TeNT) in individual reticulospinal or CoPA neurons to prevent synaptic vesicle release. We find that the axons of individual tetanus toxin expressing reticulospinal neurons have fewer myelin sheaths than controls and that their myelin sheaths are 50% shorter than controls. In stark contrast, myelination along tetanus-toxin-expressing CoPA neuron axons is entirely normal. These results indicate that while some neuronal subtypes modulate myelination by synaptic vesicle release to a striking degree in vivo, others do not. These data have implications for our understanding of how different neurons regulate myelination and thus their own function within specific neuronal circuits.
authors.affiliation: Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Koudelka
authors.affiliation: Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: Matthew G
authors.initials: MG
authors.lastname: Voas
authors.affiliation: Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.
authors.forename: Rafael G
authors.initials: RG
authors.lastname: Almeida
authors.affiliation: Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.
authors.forename: Marion
authors.initials: M
authors.lastname: Baraban
authors.affiliation: Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK.
authors.forename: Jan
authors.initials: J
authors.lastname: Soetaert
authors.affiliation: MRC Centre for Developmental Neurobiology, New Hunt's House, King's College London, Guy's Hospital Campus, London SE1 1UL, UK.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Meyer
authors.affiliation: Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA.
authors.forename: William S
authors.initials: WS
authors.lastname: Talbot
authors.affiliation: Centre for Neuroregeneration, MS Society Centre for Translational Research, Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK. Electronic address: david.lyons@ed.ac.uk.
authors.forename: David A
authors.initials: DA
authors.lastname: Lyons
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D009186:Myelin Sheath / Q000502:physiology*; D009435:Synaptic Transmission; D013572:Synaptic Vesicles / Q000378:metabolism*; D015027:Zebrafish / Q000502:physiology*