Figure 5

Irreparable merotelic kinetochore misattachments upon condensin depletion from complex centromeres. Shape and color coding generally follows Fig. 2, stars represent Aurora B molecules. (A) A 'simple' kinetochore, such as in budding yeast, with one (or few) microtubule-attachment modules, is not exposed to merotely upon decondensation of centromeric chromatin. However, the homologous Aurora B-centered machinery is present to correct syntelic misattachments. (B) Human centromeres and kinetochores suffer irreparable amount of merotely upon loss of condensin. Below: two scenarios that block repair of merotelic kinetochores deduced from analysis of condensin-depleted sister kinetochores in (40). Left - artificial balance of tension created by hyper-merotely; stretching both centromeres and kinetochores is illustrated. Right - centromere decondensation may result in individual microtubule-binding modules being removed from the zone where Aurora B is localized; a putative centromeric DNA break is depicted by a gap in the dotted line.