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Cytoplasmic dynein is required for poleward chromosome movement during mitosis in Drosophila embryos
D J Sharp1, G C Rogers, J M Scholey
1Section of Molecular and Cellular Biology, University of California-Davis, 1 Shields Avenue, Davis, California 95616, USA.
Abstract:
The movement of chromosomes during mitosis occurs on a bipolar, microtubule-based protein machine, the mitotic spindle. It has long been proposed that poleward chromosome movements that occur during prometaphase and anaphase A are driven by the microtubule motor cytoplasmic dynein, which binds to kinetochores and transports them toward the minus ends of spindle microtubules. Here we evaluate this hypothesis using time-lapse confocal microscopy to visualize, in real time, kinetochore and chromatid movements in living Drosophila embryos in the presence and absence of specific inhibitors of cytoplasmic dynein. Our results show that dynein inhibitors disrupt the alignment of kinetochores on the metaphase spindle equator and also interfere with kinetochore- and chromatid-to-pole movements during anaphase A. Thus, dynein is essential for poleward chromosome motility throughout mitosis in Drosophila embryos.
Insights
Cytoplasmic dynein is essential for chromosome movement during mitosis. Inhibiting this motor protein disrupts chromosome alignment and poleward transport in Drosophila embryos.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Mitosis involves precise chromosome segregation, crucial for cell division.
- The mitotic spindle, a microtubule-based machine, orchestrates chromosome movement.
- Cytoplasmic dynein is hypothesized to drive poleward chromosome transport via kinetochore binding.
Purpose of the Study:
- To investigate the role of cytoplasmic dynein in chromosome motility during mitosis.
- To experimentally validate the hypothesis that cytoplasmic dynein drives poleward chromosome movements.
Main Methods:
- Utilized time-lapse confocal microscopy for real-time visualization.
- Observed kinetochore and chromatid movements in living Drosophila embryos.
- Assessed effects of specific cytoplasmic dynein inhibitors.
Main Results:
- Dynein inhibition disrupted kinetochore alignment at the metaphase spindle equator.
- Inhibitors interfered with kinetochore and chromatid-to-pole movements during anaphase A.
- Confirmed dynein's essential role in poleward chromosome motility.
Conclusions:
- Cytoplasmic dynein is indispensable for poleward chromosome motility throughout mitosis.
- The findings support the hypothesis of dynein's function in chromosome segregation.
- This study provides critical insights into the mechanics of chromosome movement.