IMA Postdoc Seminar (May 20, 2008)

Speaker: Duncan Clarke (University of Minnesota)

Title: The cohesin ring is required for centrosome integrity

Abstract: Cohesin is a protein complex which forms a ring structure involved in tethering newly replicated DNA molecules until chromosome segregation in mitosis. We present the unexpected finding that Cohesin Rings are, in addition, needed for the integrity of the centrosome, an organelle that organizes the nucleation of microtubules to form the mitotic spindle. Time lapse microscopy of centrosomes and spindles in living cells revealed that in cells lacking Cohesin, the centrosomes become split during mitosis forming supernumerary spindle poles. This causes the chromosomes to segregate unevenly, leading to aneuploidy. We conclude that the Cohesin Ring is needed for the integrity of the centrosome during mitosis and therefore for proper chromosome segregation.