Related Experiment Videos
Interpolar spindle microtubules in PTK cells
D N Mastronarde1, K L McDonald, R Ding
1Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder 80309-0347.
The Journal of Cell Biology
|December 1, 1993
Summary
Interpolar microtubules (ipMTs) bundle and rearrange during mitosis, but their minus ends do not slide significantly. Minus ends of ipMTs release from kinetochore MTs, enabling spindle elongation.
Area of Science:
- Cell Biology
- Cytoskeleton Dynamics
- Mitotic Spindle Organization
Background:
- Spindle microtubules are crucial for chromosome segregation during cell division.
- Interpolar microtubules (ipMTs) and kinetochore microtubules (kMTs) have distinct roles in spindle formation and function.
Purpose of the Study:
- To investigate the structural organization and dynamics of interpolar microtubules (ipMTs) during mitosis in PtK1 cells.
- To elucidate the relationship between ipMTs and kinetochore microtubules (kMTs) throughout different mitotic stages.
Main Methods:
- 3D reconstruction of spindle microtubules using serial section electron microscopy.
- Computer image processing to analyze microtubule organization and spatial distribution.
- Quantitative analysis of microtubule minus and plus end positions and associations.
Main Results:
- ipMTs form antiparallel bundles that become more pronounced during anaphase.
- ipMT minus ends are distributed broadly, unlike kMT minus ends which are pole-associated.
- ipMT minus ends associate with kMT bundles during anaphase A, but release during anaphase B, correlating with spindle elongation.
Conclusions:
- Microtubule sliding between ipMTs contributes minimally to anaphase B spindle elongation.
- The release of ipMT minus ends from kMTs is a key event facilitating spindle pole separation and elongation.
- Specific interactions between ipMT and kMT minus ends are suggested during early anaphase.