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1 Program in Molecular Biology, University of Colorado Health Sciences Center, Aurora, Colorado 80045, USA; 2 Department of Biochemistry and Molecular Genetics, University of Colorado Health Sciences Center, Aurora, Colorado 80045, USA
Sister chromatid cohesion, conferred by the evolutionarily conserved cohesin complex, is essential for proper chromosome segregation. Cohesin binds to discrete sites along chromosome arms, and is especially enriched surrounding centromeres, but past studies have not clearly defined the roles of arm and pericentromeric cohesion in chromosome segregation. To address this issue, we developed a technique that specifically reduced pericentromeric cohesin association on a single chromosome without affecting arm cohesin binding. Under these conditions, we observed more extensive stretching of centromeric chromatin and elevated frequencies of chromosome loss, suggesting that pericentromeric cohesin enrichment is essential for high-fidelity chromosome transmission. The magnitude of pericentromeric cohesin association was negatively correlated with tension between sister kinetochores, with the highest levels of association in cells lacking kinetochoremicrotubule attachments. Pericentromeric cohesin recruitment required evolutionarily conserved components of the inner and central kinetochore. Together, these observations suggest that pericentromeric cohesin levels reflect the balance of opposing forces: the kinetochore-mediated enhancement of cohesin binding and the disruption of binding by mechanical tension at kinetochores. The involvement of conserved kinetochore components suggests that this pathway for pericentromeric cohesin enrichment may have been retained in higher eukaryotes to promote chromosome biorientation and accurate sister chromatid segregation.
[Keywords: Chromosome biorientation; sister chromatid cohesion; cohesin; kinetochore; mitosis; genomic integrity]
Received October 2, 2006; revised version accepted December 5, 2006.
E-MAIL paul.megee{at}uchsc.edu; FAX (303) 724-3215.
Supplemental material is available at http://www.genesdev.org.
Article published online ahead of print. Article and publication date are online at http://www.genesdev.org/cgi/doi/10.1101/gad.1498707
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Genes & Dev. 2007 21: 238-241.
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