Fig. 6.

The potential role of centromeres in genome-wide mobility. (A) Comparison between the moving volumes of centromeres and the genomic loci. On the basis of the mean distances shown in Fig. 4A, cells were classified into two groups in which mean distances between centromeres and the genomic loci were below or above 1.0 µm. In individual cells, the moving volumes of centromeres and the genomic loci were estimated as described in Fig. 2A. The moving volumes of centromeres and the genomic loci at the last time-point (5 minutes) are plotted. The dotted circle represents cells with a moving volume of less than 0.4 µm³ for the genomic loci. (B) Representative data showing a 5-minute tracking of centromeres (Mis12–mCherry, red) and the c417 Pol III gene locus (green) in cells with mean distances below (left) and above 1.0 µm (right). Scale bar: 1 µm. (C) A model for the role of centromeric motion in the mobility of other genomic regions. Microtubule polymerization in cytoplasm actively pushes centromeres in nucleoplasm. Centromeres transiently associate with genomic loci carrying Pol III genes and retrotransposons. These associations are mediated by condensin. Centromeres and their associating genomic loci migrate in a coordinated fashion. Because Pol IIl genes and retrotransposons are dispersed throughout the genome, centromeric motion regulated by cytoplasmic microtubules can potentially impact genome-wide mobility.