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In vitro acylation of myelin PLP and DM-20 in the quaking mouse brain
H C Agrawal1, D Agrawal, T Yoshimura
1Department of Pediatrics, Washington University School of Medicine, St. Louis, MO 63110.
Abstract:
Both proteolipid proteins (PLP) and DM-20 were found to be present by the immunoblot technique in myelin isolated from quaking mouse brain; however, the relative concentration of these proteins in myelin from quaking brain was substantially reduced when compared to the control. Brain slices from littermate control and quaking mice were incubated with [3H]palmitic acid to determine the incorporation of fatty acid into myelin proteolipid proteins. Fluorography of gels containing myelin proteins from control and quaking mice brain revealed that both PLP and DM-20 were acylated. The incorporation of [3H]palmitic acid into quaking myelin PLP and DM-20 was reduced by 75% and 20% respectively of those in control brain. The significance of differential acylation of quaking myelin PLP and DM-20 is discussed with respect to availability of non-acylated pools of proteolipid proteins and the activities of acylating enzymes.
Insights
Quaking mice exhibit reduced levels of myelin proteolipid proteins (PLP) and DM-20. Fatty acid incorporation into these proteins is significantly impaired in quaking mice, suggesting altered acylation processes.
Area of Science:
- Neuroscience
- Biochemistry
- Molecular Biology
Background:
- The myelin sheath, crucial for nerve impulse conduction, is rich in proteolipid proteins (PLP) and its isoform DM-20.
- The quaking mouse model exhibits dysmyelination, characterized by reduced myelin content and altered protein composition.
Purpose of the Study:
- To investigate the acylation status of PLP and DM-20 in the myelin of quaking mice.
- To compare fatty acid incorporation into PLP and DM-20 between control and quaking mouse brains.
Main Methods:
- Immunoblotting was used to detect PLP and DM-20 in isolated myelin from control and quaking mouse brains.
- Brain slices were incubated with [3H]palmitic acid, followed by fluorography to assess fatty acid incorporation into myelin proteins.
Main Results:
- Myelin from quaking mice showed substantially reduced concentrations of both PLP and DM-20 compared to controls.
- Fluorography revealed that both PLP and DM-20 are acylated in control and quaking mouse brains.
- Fatty acid incorporation into quaking myelin PLP and DM-20 was reduced by 75% and 20%, respectively, compared to controls.
Conclusions:
- Acylation of PLP and DM-20 is significantly impaired in the quaking mouse model.
- Differential acylation of PLP and DM-20 in quaking mice may relate to the availability of non-acylated protein pools or altered acylating enzyme activity.