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Establishment of a stable, acetylated microtubule bundle during neuronal commitment
M M Falconer1, U Vielkind, D L Brown
1Department of Biology, University of Ottawa, Ontario, Canada.
Cell Motility and the Cytoskeleton
|January 1, 1989
Summary
Stable microtubule (MT) modifications, including acetylation and detyrosination, initiate during neuronal commitment in P19 cells before differentiation. These early MT changes precede neurite formation and MAP 2 detection, suggesting a novel role for MT stability in early neurogenesis.
Area of Science:
- Cell Biology
- Neuroscience
- Developmental Biology
Background:
- Posttranslational modifications of alpha-tubulin, such as acetylation and detyrosination, are linked to stable microtubule (MT) populations in neuronal processes.
- P19 embryonal carcinoma cells offer a model to study MT changes during neurogenesis, encompassing both commitment and differentiation phases.
Purpose of the Study:
- To investigate the changes in microtubule (MT) isotype and stability during neurogenesis using the P19 cell line.
- To determine when MT modifications associated with stable MTs first appear during neuronal commitment and differentiation.
Main Methods:
- Utilized indirect immunofluorescence microscopy to observe microtubule (MT) arrays in P19 cells.
- Examined MT modifications, including acetylation and detyrosination, following neuronal induction with retinoic acid (RA).
- Assessed the presence of microtubule-associated proteins (MAPs), including MAP 2, during differentiation.
Main Results:
- Uncommitted P19 cells exhibit minimal acetylated and detyrosinated MTs.
- Neuronal induction with retinoic acid (RA) triggers MT modifications during commitment, preceding observable morphological changes.
- A transiently enlarged MT population forms, including a novel, colchicine-stable array of acetylated MTs, even before microtubule-associated protein (MAP) detection.
- Evidence suggests the acetylated MT bundle extends to form neurites, with MAP 2 appearing around neurite extension.
Conclusions:
- Stable microtubule (MT) populations in mature neurons may originate during the neuronal commitment phase.
- Early MT acetylation and stabilization occur prior to significant morphological differentiation and MAP 2 expression.
- This study provides the first evidence linking MT stability initiation to neuronal commitment.