Fig. 4.

Chromosome segregation in meiosis. In metaphase I bivalents, cohesin complexes are located at the interchromatid domain along the arms and at the inner centromere domain below the closely associated sister kinetochores. At the onset of anaphase I, only the cohesin complexes at the arms are cleaved by separase to allow segregation of recombined homologues to opposite poles. Centromere cohesins are protected by SGO/PP2A. In metaphase II chromosomes, sister kinetochores attach to microtubules from opposite poles, and cohesin complexes are found at the inner centromere domain. In late prometaphase II chromosomes in mammals, the interaction of microtubules from opposite poles with sister kinetochores generates tension across the centromere and triggers the redistribution of SGO2 and probably PP2A delocalization from centromeres. During the metaphase II/anaphase II transition, separase is now able to cleave remaining centromeric cohesin complexes to trigger chromatid segregation. The chromosomes depicted are telocentric