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Updated: May 17, 2026
Live Cell Imaging to Assess the Dynamics of Metaphase Timing and Cell Fate Following Mitotic Spindle Perturbations
Published on: September 20, 2019
Microtubule dynamics alter the interphase nucleus
Gabi Gerlitz1, Orly Reiner, Michael Bustin
1Protein Section, Laboratory of Metabolism, National Cancer Institute, US National Institutes of Health, Bethesda, MD 20892, USA. gabi.gerlitz@gmail.com
Abstract:
Microtubules are known to drive chromosome movements and to induce nuclear envelope breakdown during mitosis and meiosis. Here we show that microtubules can enforce nuclear envelope folding and alter the levels of nuclear envelope-associated heterochromatin during interphase, when the nuclear envelope is intact. Microtubule reassembly, after chemically induced depolymerization led to folding of the nuclear envelope and to a transient accumulation of condensed chromatin at the site nearest the microtubule organizing center (MTOC). This microtubule-dependent chromatin accumulation next to the MTOC is dependent on the composition of the nuclear lamina and the activity of the dynein motor protein. We suggest that forces originating from simultaneous polymerization of microtubule fibers deform the nuclear membrane and the underlying lamina. Whereas dynein motor complexes localized to the nuclear envelope that slide along the microtubules transfer forces and/or signals into the nucleus to induce chromatin reorganization and accumulation at the nuclear membrane folds. Thus, our study identified a molecular mechanism by which mechanical forces generated in the cytoplasm reshape the nuclear envelope, alter the intranuclear organization of chromatin, and affect the architecture of the interphase nucleus.
Insights
Microtubules mechanically deform the nuclear envelope during interphase, causing folding and relocating heterochromatin. This process involves the microtubule organizing center (MTOC) and dynein motor proteins, impacting nuclear architecture.
Area of Science:
- Cell Biology
- Cytoskeleton Dynamics
- Nuclear Architecture
Background:
- Microtubules are crucial for chromosome segregation during cell division.
- The nuclear envelope's role in interphase nuclear organization is less understood.
- Cytoplasmic forces influencing nuclear structure are an active area of research.
Purpose of the Study:
- To investigate the role of microtubules in shaping the interphase nuclear envelope.
- To determine how microtubules affect heterochromatin organization within the nucleus.
- To elucidate the molecular mechanisms linking microtubule dynamics to nuclear architecture.
Main Methods:
- Chemically induced depolymerization and reassembly of microtubules.
- Microscopy to observe nuclear envelope morphology and chromatin distribution.
- Investigating the roles of nuclear lamina composition and dynein motor activity.
Main Results:
- Microtubule reassembly induced nuclear envelope folding.
- Condensed chromatin transiently accumulated near the microtubule organizing center (MTOC).
- This accumulation depended on nuclear lamina and dynein motor protein activity.
Conclusions:
- Cytoplasmic mechanical forces from microtubules can deform the interphase nuclear envelope.
- Dynein motor proteins mediate force/signal transfer to reorganize intranuclear chromatin.
- Microtubules actively influence interphase nuclear architecture by altering chromatin organization.
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