Affiliation:
1. Department of Molecular and Cell Biology, 311 Life Sciences Addition, University of California, Berkeley, CA 94720-3200, USA
Abstract
To facilitate their accurate distribution by the mitotic spindle, sister chromatids are tethered during DNA replication, attached by their kinetochores and bi-oriented on the spindle, and then simultaneously released at the metaphase to anaphase transition, allowing for their segregation to opposite spindle poles. The highly conserved cohesin complex is fundamental to this process, yet its role in mitosis is not fully understood. We show that depletion of cohesin from Xenopus egg extracts impairs sister chromatid cohesion and kinetochore-microtubule interactions, causing defective spindle attachments and chromosome alignment during metaphase and mis-segregation during anaphase. In the absence of cohesin, sister kinetochore pairing and centromeric localization of chromosomal passenger proteins INCENP and aurora B were lost upon bipolar spindle attachment. However, kinetochores remained paired with normal passenger localization if bipolar spindle formation was prevented by inhibiting the kinesin-5 motor (Eg5). These observations indicate that cohesin is not required to establish sister association, but is necessary to maintain cohesion in the presence of bipolar spindle forces. Co-depletion of cohesin together with another major SMC complex, condensin, revealed cumulative effects on spindle assembly and chromosome architecture. These data underscore the essential requirement for cohesin in sister chromatid cohesion, kinetochore and spindle function.
Publisher
The Company of Biologists
Reference36 articles.
1. Chen, H., Hughes, D. D., Chan, T. A., Sedat, J. W. and Agard, D. A. (1996). IVE (Image Visualization Environment): a software platform for all three-dimensional microscopy applications. J. Struct. Biol.116, 56-60.
2. Cleveland, D. W., Mao, Y. and Sullivan, K. F. (2003). Centromeres and kinetochores: from epigenetics to mitotic checkpoint signaling. Cell112, 407-421.
3. Desai, A., Murray, A., Mitchison, T. J. and Walczak, C. E. (1999). The use of Xenopus egg extracts to study mitotic spindle assembly and function in vitro. Methods Cell Biol.61, 385-412.
4. Downes, C. S., Mullinger, A. M. and Johnson, R. T. (1991). Inhibitors of DNA topoisomerase II prevent chromatid separation in mammalian cells but do not prevent exit from mitosis. Proc. Natl. Acad. Sci. USA88, 8895-8899.
5. Dynek, J. N. and Smith, S. (2004). Resolution of sister telomere association is required for progression through mitosis. Science304, 97-100.
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