PUBLICATION
alphaII-Spectrin Is Essential for Assembly of the Nodes of Ranvier in Myelinated Axons
- Authors
- Voas, M.G., Lyons, D.A., Naylor, S.G., Arana, N., Rasband, M.N., and Talbot, W.S.
- ID
- ZDB-PUB-070303-44
- Date
- 2007
- Source
- Current biology : CB 17(6): 562-568 (Journal)
- Registered Authors
- Arana, Naomi, Lyons, David A., Naylor, Stephen, Talbot, William S., Voas, Matthew G.
- Keywords
- none
- MeSH Terms
-
- Animals
- Axons/metabolism*
- Axons/ultrastructure
- Microscopy, Electron, Transmission
- Molecular Sequence Data
- Mutation
- Ranvier's Nodes/metabolism*
- Ranvier's Nodes/ultrastructure
- Sodium Channels/metabolism
- Spectrin/genetics
- Spectrin/physiology*
- Zebrafish/metabolism*
- PubMed
- 17331725 Full text @ Curr. Biol.
Citation
Voas, M.G., Lyons, D.A., Naylor, S.G., Arana, N., Rasband, M.N., and Talbot, W.S. (2007) alphaII-Spectrin Is Essential for Assembly of the Nodes of Ranvier in Myelinated Axons. Current biology : CB. 17(6):562-568.
Abstract
Saltatory conduction in myelinated axons requires organization of the nodes of Ranvier, where voltage-gated sodium channels are prominently localized [1]. Previous results indicate that alphaII-spectrin, a component of the cortical cytoskeleton [2], is enriched at the paranodes [3, 4], which flank the node of Ranvier, but alphaII-spectrin's function has not been investigated. Starting with a genetic screen in zebrafish, we discovered in alphaII-spectrin (alphaII-spn) a mutation that disrupts nodal sodium-channel clusters in myelinated axons of the PNS and CNS. In alphaII-spn mutants, the nodal sodium-channel clusters are reduced in number and disrupted at early stages. Analysis of chimeric animals indicated that alphaII-spn functions autonomously in neurons. Ultrastructural studies show that myelin forms in the posterior lateral line nerve and in the ventral spinal cord in alphaII-spn mutants and that the node is abnormally long; these findings indicate that alphaII-spn is required for the assembly of a mature node of the correct length. We find that alphaII-spectrin is enriched in nodes and paranodes at early stages and that the nodal expression diminishes as nodes mature. Our results provide functional evidence that alphaII-spectrin in the axonal cytoskeleton is essential for stabilizing nascent sodium-channel clusters and assembling the mature node of Ranvier.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping