Conserved features of cohesin binding along fission yeast chromosomes
1 Chromosome Segregation Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields, London WC2A 3PX, UK
2 Bioinformatics and Biostatistics Service, Cancer Research UK London Research Institute, Lincoln's Inn Fields, London WC2A 3PX, UK
3 Current address: National Cancer Institute, NIH, Bethesda, MD 20892, USA
4 Current address: Trinity Centre for High Performance Computing, Trinity College, Dublin 2, Ireland
Genome Biology 2009, 10:R52 doi:10.1186/gb-2009-10-5-r52Published: 19 May 2009
Cohesin holds sister chromatids together to enable their accurate segregation in mitosis. How, and where, cohesin binds to chromosomes are still poorly understood, and recent genome-wide surveys have revealed an apparent disparity between its chromosomal association patterns in different organisms.
Here, we present the high-resolution analysis of cohesin localization along fission yeast chromosomes. This reveals that several determinants, thought specific for different organisms, come together to shape the overall distribution. Cohesin is detected at chromosomal loading sites, characterized by the cohesin loader Mis4/Ssl3, in regions of strong transcriptional activity. Cohesin also responds to transcription by downstream translocation and accumulation at convergent transcriptional terminators surrounding the loading sites. As cells enter mitosis, a fraction of cohesin leaves chromosomes in a cleavage-independent reaction, while a substantial pool of cohesin dissociates when it is cleaved at anaphase onset. We furthermore observe that centromeric cohesin spreads out onto chromosome arms during mitosis, dependent on Aurora B kinase activity, emphasizing the plasticity of cohesin behavior.
Our findings suggest that features that were thought to differentiate cohesin between organisms collectively define the overall behavior of fission yeast cohesin. Apparent differences between organisms might reflect an emphasis on different aspects, rather than different principles, of cohesin action.