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Disturbed oligodendrocyte development and recovery from hypomyelination in a c-myc transgenic mouse mutant
J M Orian1, A J Ahern, M M Ayers
1Department of Neuroinflammation, Imperial College School of Medicine, Charing Cross Campus, London, United Kingdom. orian@bioserve.latrobe.edu.u
Abstract:
The complexity of interactions underlying the elaboration of myelin has been extensively demonstrated. We provide evidence that signals promoting myelination are not confined to the normal developmental time window for myelination and persist well into adult life. The 2-50 mutant, described previously, carries a c-myc transgene regulated by a myelin basic protein promoter. This mutant is characterised by severe hypomyelination and abnormal oligodendrocytes in early life, followed by loss of the phenotype and normal longevity. We show that c-myc expression in early oligodendrocyte development results in a substantial reduction of cells of this lineage. However, apparent complete recovery, associated with loss of c-myc expression, axonal survival, and gradual myelin accumulation, is observed by 4 months of age. Thus, stimulation of myelination continues during adult life until normal myelin levels are established. We propose that this mutant may contribute to the characterisation of oligodendrocyte responses to myelinating signals.
Insights
Myelination signals persist into adulthood, not just development. A c-myc mutant shows early hypomyelination that recovers, revealing ongoing oligodendrocyte responses to myelinating signals.
Area of Science:
- Neuroscience
- Cell Biology
- Developmental Biology
Background:
- Myelination is crucial for nervous system function.
- Oligodendrocytes are the myelin-producing cells in the central nervous system.
- The developmental timing of myelination is not fully understood.
Purpose of the Study:
- To investigate if myelination signals persist beyond the typical developmental window.
- To characterize the role of c-myc in oligodendrocyte development and myelination.
- To explore oligodendrocyte responses to myelinating signals in adult life.
Main Methods:
- Utilized a transgenic mouse model (2-50 mutant) with a c-myc transgene under a myelin basic protein promoter.
- Observed oligodendrocyte populations and myelination status at different developmental time points.
- Assessed c-myc expression levels and correlated them with cellular phenotypes.
Main Results:
- Early c-myc expression in oligodendrocytes led to reduced cell numbers and severe hypomyelination.
- The mutant mice exhibited a loss of the hypomyelination phenotype by 4 months of age.
- Recovery was associated with decreased c-myc expression, axonal survival, and myelin accumulation.
Conclusions:
- Myelination signals are active during adult life, continuing until normal myelin levels are achieved.
- c-myc dysregulation in early oligodendrocyte development causes transient hypomyelination.
- The 2-50 mutant provides a model for studying oligodendrocyte responses to myelination stimuli in adulthood.