Myelin basic protein-specific protein methylase I activity in shiverer mutant mouse brain

Area of Science:

• Neuroscience
• Biochemistry
• Genetics

Background:

• Myelin basic protein (MBP) is crucial for myelin sheath formation.
• Shiverer (shi/shi) mutant mice exhibit dysmyelination.
• Protein-arginine N-methyltransferase (PRMT) enzymes play roles in protein modification.

Purpose of the Study:

• To investigate myelin basic protein (MBP)-specific protein-arginine N-methyltransferase (PRMT) activity in shiverer mutant mice.
• To compare PRMT activity during myelination in shiverer mutants versus normal littermates and jimpy mice.

Main Methods:

• Enzyme activity assays measuring S-adenosyl-L-[methyl-14C]methionine incorporation.
• Comparison of enzyme activity in homozygous shiverer (shi/shi) mutant brains and normal littermate brains at different ages.
• Analysis of brain weight and protein concentration.

Main Results:

• Shiverer mutant brains show significantly higher MBP-specific PRMT activity at the onset of myelination compared to normal brains.
• Enzyme activity increases with myelination in normal brains but decreases in shiverer mutants.
• No significant differences in brain weight or protein concentration were observed between shiverer and normal brains.
• Histone-specific PRMT activity remained unaffected in shiverer brains.

Conclusions:

• MBP-specific PRMT activity is altered in shiverer mutant mice during the critical myelination period.
• The altered enzyme activity pattern in shiverer mutants contrasts with normal development and the jimpy mouse model.
• These findings suggest a specific role for MBP-specific PRMT in myelin formation and shiverer pathogenesis.