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A potential role for human cohesin in mitotic spindle aster assembly
H C Gregson1, J A Schmiesing, J S Kim
1Department of Biological Chemistry, College of Medicine, University of California, Irvine, CA 92697-1700, USA.
The Journal of Biological Chemistry
|October 9, 2001
Summary
Cohesin is essential for sister chromatid cohesion. New findings reveal cohesin also localizes to spindle poles during mitosis, interacting with NuMA and potentially aiding spindle assembly.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- The cohesin complex (SMC1, SMC3, SA, Rad21) is crucial for sister chromatid cohesion in eukaryotes.
- While cohesin functions in interphase cohesion, most is cytoplasmic during metaphase.
- Antibody injection targeting SMC1 disrupts metaphase, suggesting a vital mitotic role.
Purpose of the Study:
- To investigate the subcellular localization and mitotic function of human cohesin.
- To explore cohesin's interaction with spindle pole-associated factors during mitosis.
Main Methods:
- Re-examination of cohesin component localization in human cells.
- Co-immunoprecipitation to study protein interactions.
- In vitro assays to assess spindle assembly in the absence of cohesin.
Main Results:
- Cohesin localizes to spindle poles during mitosis and interacts with NuMA.
- This interaction with NuMA is maintained during interphase.
- Cohesin also associates with the nuclear matrix.
- Mitotic spindle asters fail to form in vitro without cohesin.
Conclusions:
- Human cohesin plays a significant role in mitosis beyond sister chromatid cohesion.
- Cohesin's interaction with NuMA suggests a novel function in mitotic spindle organization.
- Cohesin may be involved in spindle assembly during mitosis.