Displacement and re-accumulation of centromeric cohesin during transient pre-anaphase centromere splitting |
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Authors: | Maria T Ocampo-Hafalla Yuki Katou Katsuhiko Shirahige Frank Uhlmann |
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Institution: | (1) Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London, WC2A 3PX, UK;(2) Center for Biological Resources and Informatics, Division of Gene Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan |
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Abstract: | The ring-shaped cohesin complex links sister chromatids until their timely segregation during mitosis. Cohesin is enriched
at centromeres where it provides the cohesive counterforce to bipolar tension produced by the mitotic spindle. As a consequence
of spindle tension, centromeric sequences transiently split in pre-anaphase cells, in some organisms up to several micrometers.
This ‘centromere breathing’ presents a paradox, how sister sequences separate where cohesin is most enriched. We now show
that in the budding yeast Saccharomyces cerevisiae, cohesin binding diminishes over centromeric sequences that split during breathing. We see no evidence for cohesin translocation
to surrounding sequences, suggesting that cohesin is removed from centromeres during breathing. Two pools of cohesin can be
distinguished. Cohesin loaded before DNA replication, which has established sister chromatid cohesion, disappears during breathing.
In contrast, cohesin loaded after DNA replication is partly retained. As sister centromeres re-associate after transient separation,
cohesin is reloaded in a manner independent of the canonical cohesin loader Scc2/Scc4. Efficient centromere re-association
requires the cohesion establishment factor Eco1, suggesting that re-establishment of sister chromatid cohesion contributes
to the dynamic behaviour of centromeres in mitosis. These findings provide new insights into cohesin behaviour at centromeres.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. |
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