Fig. 3.

The activity status of NORs as determined by UBF loading. (A) Immuno-FISH performed metaphase spreads prepared from hTert-RPE1, 1BR3, and CCD-1079Sk cells visualizing rDNA (red) and UBF (green). Chromosomes were stained with DAPI. Active NORs are indicated by either an asterisk or a number. Enlarged versions of three numbered chromosomes from each cell type are shown at the right. (B) Silver staining performed on metaphase spreads prepared from hTert-RPE1 and CCD-1079Sk cells. Silver-positive NORs are indicated by red circles.