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Updated: May 7, 2026
Mouse Models of Periventricular Leukomalacia
Published on: May 18, 2010
Absence of MBP 3' UTR in Mice Disrupts mRNA Transport, Myelination, and Motor Learning
Joseph C Nowacki1, Haidyn L Bulen2, Lindsey M Meservey3
1National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
Abstract:
Myelin sheath maturation requires compaction, a cellular phenomenon mediated by local translation of myelin basic protein (MBP), which acts as a molecular zipper to join adjacent membranes and extrude the cytoplasm. Contrary to decades-old microinjection experiments indicating that Mbp mRNA transport is restricted to microtubules, we now show using smFISH that endogenous Mbp mRNA granules indeed localize along actin. To validate the in vivo necessity of Mbp mRNA transport and its dependence on the 3' UTR (untranslated region), we replaced the endogenous Mbp 3' UTR with polyA tail sequences. Though these mice have decreased Mbp mRNA levels, this alone could not account for their striking phenotypes - hypomyelination, baseline tremors, and motor learning defects. Thus, we cultured oligodendrocytes from these mice and found defects in both Mbp mRNA localization and local translation. These results demonstrate that the 3' UTR of a locally translated structural protein is critical for both developmental and activity-induced myelination.
Insights
Myelin basic protein (MBP) mRNA localization is critical for myelin sheath development. Our study shows MBP mRNA travels along actin filaments, not microtubules, impacting myelination and motor function.
Area of Science:
- Neuroscience
- Cell Biology
- Molecular Biology
Background:
- Myelin sheath maturation is essential for proper nervous system function.
- Local translation of myelin basic protein (MBP) is crucial for myelin compaction.
- Previous research suggested Mbp mRNA transport is restricted to microtubules.
Purpose of the Study:
- To investigate the transport mechanism of endogenous Mbp mRNA.
- To determine the role of the 3' untranslated region (UTR) in Mbp mRNA transport and function.
- To elucidate the impact of impaired Mbp mRNA transport on myelination and motor behavior.
Main Methods:
- Single-molecule fluorescence in situ hybridization (smFISH) to track Mbp mRNA localization.
- Generation of genetically modified mice with altered Mbp 3' UTR sequences.
- Culturing of oligodendrocytes from these mice to assess mRNA localization and translation.
- Phenotypic analysis including motor learning and tremor assessment.
Main Results:
- Endogenous Mbp mRNA granules were found to localize along actin filaments, challenging previous findings.
- Mice with modified Mbp 3' UTR exhibited hypomyelination, tremors, and motor learning deficits.
- Oligodendrocytes from these mice showed defects in both Mbp mRNA localization and local translation.
Conclusions:
- The 3' UTR of Mbp mRNA is critical for its proper localization and local translation.
- Actin-based transport of Mbp mRNA is essential for developmental and activity-induced myelination.
- Disruptions in Mbp mRNA transport lead to significant neurological deficits.
