Related Experiment Videos
Distribution of myelin basic protein and P2 mRNAs in rabbit spinal cord oligodendrocytes
C S Gillespie1, B D Trapp, D R Colman
1Division of Cell Biology and Biochemistry, School of Molecular and Biological Sciences, University of Stirling, Scotland.
Abstract:
Myelin basic protein (MBP) and P2 protein are small positively charged proteins found in oligodendrocytes of rabbit spinal cord. Both proteins become incorporated into compact myelin. We have begun investigations into the mechanisms by which MBP and P2 become incorporated into the myelin membrane. We find that P2, like the MBPs, is synthesized on free polysomes in rabbit spinal cord. Cell fractionation experiments reveal that rabbit MBP mRNAs are preferentially segregated to the peripheral myelinating regions whereas P2 mRNAs are predominantly localized within the perikaryon of the cell. In vitro synthesized rabbit MBP readily associates with membranes added to translation mixtures, whereas P2 protein does not. It is possible that P2 requires a "receptor" molecule, perhaps a membrane-anchored protein, for association with the cytoplasmic face of the myelin membrane.
Insights
Myelin basic protein (MBP) and P2 protein are key to myelin formation. MBP readily associates with membranes, while P2 protein may require a receptor for myelin membrane incorporation.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Myelin basic protein (MBP) and P2 protein are essential positively charged proteins in rabbit spinal cord oligodendrocytes.
- Both MBP and P2 are integral components of compact myelin.
Purpose of the Study:
- To investigate the distinct mechanisms of MBP and P2 protein incorporation into the myelin membrane.
- To understand the synthesis and localization of MBP and P2 during myelination.
Main Methods:
- Analysis of protein synthesis on free polysomes.
- Cell fractionation to determine mRNA localization (MBP vs. P2).
- In vitro translation assays to assess membrane association.
Main Results:
- Both MBP and P2 proteins are synthesized on free polysomes in rabbit spinal cord.
- MBP mRNA is preferentially localized to peripheral myelinating regions, while P2 mRNA is mainly in the perikaryon.
- In vitro synthesized MBP associates with membranes, but P2 protein does not.
Conclusions:
- MBP and P2 proteins exhibit differential mechanisms for myelin membrane incorporation.
- P2 protein's lack of direct membrane association suggests a potential requirement for a receptor molecule.