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Translocation of myelin basic protein mRNA in oligodendrocytes requires microtubules and kinesin
J H Carson1, K Worboys, K Ainger
1Department of Biochemistry, University of Connecticut Health Center, Farmington 06030, USA. jcarson@nso2.uchc.edu
Abstract:
Myelin basic protein (MBP) mRNA is localized to the myelin membranes of oligodendrocytes. When exogenous MBP mRNA is microinjected into oligodendrocytes in culture, it is transported along the processes and localized to the myelin compartment in a multistep intracellular RNA trafficking pathway. In the work described here, oligodendrocytes were treated with agents that affect the cytoskeleton including: nocodazole, to disrupt microtubules; taxol, to stabilize microtubules; cytochalasin, to disrupt microfilaments; and kinesin anti-sense oligonucleotide, to suppress kinesin expression. Digoxigenin-labeled MBP mRNA was microinjected into the treated cells and the extent of translocation of the microinjected RNA was determined by confocal microscopy. Nocodazole, taxol, and kinesin anti-sense oligonucleotide inhibited translocation of microinjected MBP mRNA, while cytochalasin B and kinesin sense oligonucleotide did not. These results indicate that translocation of MBP mRNA in oligodendrocytes requires intact microtubules and kinesin but does not require intact microfilaments. The results are discussed in relation to the current multistep model for intracellular RNA trafficking in oligodendrocytes.
Insights
Myelin basic protein (MBP) mRNA transport in oligodendrocytes depends on microtubules and kinesin. Disrupting these components inhibits RNA translocation to myelin.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Myelin basic protein (MBP) mRNA is crucial for myelin sheath formation in oligodendrocytes.
- Intracellular RNA trafficking pathways guide mRNA localization within cells.
Purpose of the Study:
- To investigate the role of the cytoskeleton in the intracellular transport of MBP mRNA in oligodendrocytes.
- To determine the specific cytoskeletal elements and motor proteins involved in MBP mRNA translocation.
Main Methods:
- Oligodendrocytes were treated with cytoskeleton-disrupting/stabilizing agents (nocodazole, taxol, cytochalasin B) and kinesin modulators (anti-sense/sense oligonucleotides).
- Exogenous digoxigenin-labeled MBP mRNA was microinjected into treated oligodendrocytes.
- Confocal microscopy was used to quantify the translocation of microinjected MBP mRNA.
Main Results:
- Microtubule disruption (nocodazole) and stabilization (taxol) inhibited MBP mRNA translocation.
- Suppression of kinesin expression via anti-sense oligonucleotides also inhibited MBP mRNA translocation.
- Disruption of microfilaments (cytochalasin B) did not affect MBP mRNA translocation.
Conclusions:
- MBP mRNA translocation in oligodendrocytes requires intact microtubules.
- Kinesin motor proteins are essential for the transport of MBP mRNA along microtubules.
- Microfilaments are not required for this specific RNA trafficking pathway.